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The battle of Tannenberg and Masurian Lakes proved to be very important battles. Both General Paul Von Hindenburg and Erich Ludendorff were instrumental in the battle to which they were touted the name “heroes of Tannenberg”. The plan was for the French and British armies to hold the German armies in the west as the Russian armies which were much larger than the Germans could organize themselves. The German commander positioned six of his divisions behind the Angerapp River west of Gumbinnen leaving a two division and a regular division near Allenstein to protect the slow advancing divisions of the Russian armies. Advanced elements clashed at Stalluponen on August 17 after which Pritwitz attacked with his three main corps at Gumbinnen three days later simultaneously. This caused much loss to the Russian army which lead to them retreating.
This would lead to the battle of Tannenberg. The Russians lack of good quality railroad networking seemed to really go against them. This aside from the fact that their trains operated on different rail gauging than the Germans. Prittwitz decided to take advantage of the lateness of Samsonov’s advance meaning the German forces could face the Russian forces separately as opposed to singly which is what Russia planned on in the first case. The German train lines dispatched three corps south to meet Samsonov leaving only Calvary and Landwehr to the west of Gumbinnen. The second army’s remaining five corps had inadequate supply lines back to Poland and virtually no communication between their other armies.
The Battle of the Masurian Lakes was another German offensive attack this time it was located in the eastern front. This battle again pushed the Russian army back this time significantly backwards. Although the tenth Russian army showed hampering further progress from Germany. This battle although another success for Germany was not as successful as Tannenberg where The... [continues]
Cite This Essay
(2013, 02). The Battle of Tannenberg and Masurian Lakes. StudyMode.com. Retrieved 02, 2013, from http://www.studymode.com/essays/The-Battle-Of-Tannenberg-And-Masurian-1429828.html
"The Battle of Tannenberg and Masurian Lakes" StudyMode.com. 02 2013. 02 2013 <http://www.studymode.com/essays/The-Battle-Of-Tannenberg-And-Masurian-1429828.html>.
"The Battle of Tannenberg and Masurian Lakes." StudyMode.com. 02, 2013. Accessed 02, 2013. http://www.studymode.com/essays/The-Battle-Of-Tannenberg-And-Masurian-1429828.html. | <urn:uuid:54648094-62fe-4546-9a37-54ebf77d4aa0> | CC-MAIN-2013-20 | http://www.studymode.com/essays/The-Battle-Of-Tannenberg-And-Masurian-1429828.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368700563008/warc/CC-MAIN-20130516103603-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.954262 | 579 | 3.75 | 4 |
Cowmen vs. Crops in 1870ís Conflict
by Derryl Dumermuth
††† It is generally conceded that the first Caucasian to view the San Joaquin Valley was Don Pedro Fages, a Spanish officer and later governor of both Baja and Alta California. It was the fall of 1772 and he entered the great valley through Tejon Pass.
††† When Mexico gained its independence from Spain in 1821, the government in faraway Mexico City rewarded influential and loyal citizens with "Land Grants", called ranchos, ranging in size from 4,500 to 50,000 acres. Soon, uninvited Americans began crowding out the native Yokuts and the Mexican ranchers
††† The Bear Flag Rebellion of 1846 wrested control of California from Mexico and was validated by the Treaty of Guadalupe Hidalgo in 1848 at the conclusion of the war with Mexico. Two years later California was admitted to the Union as a free state. Ten days before the signing of the treaty, James Marshall discovered gold on the south fork of the American River, and the "Gold Rush" was on.
††† Cattle, which had been selling for two dollars a head, mostly for hides and tallow, suddenly found an easily accessible market. Now the same cows were worth 30 to 70 dollars as beef to feed the tens of thousands of hungry miners.
††† By 1860, most of the easily found gold had been dug out of the hills. Many of the miners returned to their families in the east - a few rich, most impoverished. But a substantial number decided to stay in California, swelling the population of the few cities and creating a land boom in the San Joaquin Valley.
††† Until the arrival of the railroad in 1872, the economy of the Central Valley was based primarily on cattle and sheep, grazing free-range on the abundant grass. Row and tree crops had been limited by the prohibitive cost of transportation to market.
††† The flood of farmers into the valley changed the dynamics of the economy forever. In the musical "Oklahoma" the cast sings "The Farmer and the Cowman Should be Friends". But the truth of the matter was that they must be enemies. The cowman's free-range cattle trampled and destroyed the farmer's crops, and the farmers plowed the grassland that ranchers depended on to feed their animals. Farmers often resorted to shooting trespassing cattle. The two groups could not coexist without changes in the law.
††† Barbed wire had been invented in the 1870's, but was still not common in the west. The cost of enclosing a quarter section of farmland with a board or rail fence was estimated at $2,230, an astronomical sum out of the reach of early-day farmers. They supported passage of a state law (the No Fence Law) aimed at forcing cattlemen to control their animals, a measure first proposed by Stephen Barton, editor of the Visalia Times. Tulare at that time was represented in the state senate by Thomas Fowler, a wealthy cattleman who had blocked several attempts to pass the no-fence law.
††† The 1873 election was bitterly contested with Fowler opposed by Tipton Lindsay, who supported the law. Lindsay won the senate seat, and at the same time Fresno County elected John W. Fergusun, also a "no-fence man, to the assembly. In the next session of the legislature the measure was introduced by these two men and, after much controversy, was made law.
††† Application of the law forced ranchers to prevent their livestock from trespassing onto the property of others and held them liable for damage or injuries in the event the animals strayed onto the ever-increasing acres of cultivated land.
††† Derryl Dumermuth is a retired TUHS mathematics teacher, author of "A Town Called Tulare", and co-author with his wife, Wanda, of "Tulare Legends and Trivia from A to Z". Both books were written as fund-raisers for the Tulare Historical Museum and can be purchased in the Museum's gift shop.
1.† Free-range longhorns in the San Joaquin Valley.† | <urn:uuid:41ab8078-d820-4ffd-a956-37df458e222d> | CC-MAIN-2013-20 | http://www.tularehistoricalmuseum.org/Gallery%20page%20articles/Cowmen%20vs.%20Cropsr.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368700563008/warc/CC-MAIN-20130516103603-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.97423 | 882 | 3.765625 | 4 |
Building a Bridge Toward a 21st Century Multi-Racial Multi-Cultural Society:
Tearing Down Walls of Hate, Ignorance and Fear
Developing a Common Language for All to Access
Glossary of Terms and Definitions
A : B : C : D : E : F : G : H : I : L : M : N : O : P : Q : R : S : T : W
Literally “mixed” or “hybrid,” this term is increasingly used to identify “the origination of a new people from two ethnically disparate parent peoples.” The primary reference is to the Spanish and Native American cultural heritage of Mexico, but it has also been used to identify Hispanics in the United States.
A group or subgroup, or a member of such, which has limited access to positions of power and therefore little influence upon the larger group, institution, or society.
Since women (who are roughly fifty percent of the population) are often, but not always, referred to as a minority group (some use the phrase “minorities and women” to reference those outside the dominating “majority”), and African Americans and Hispanics retain their “minority” status even if they constitute over fifty percent of the population of an area, it is clear that “minority” is not determined numerically.
The term is considered by some to have derogatory connotations, and some writers seek to avoid the term altogether by using positive designations such as persons of color or “primarily Black” schools and so forth.
This term is used in a variety of ways and is less often defined by its users than terms such as multiculturalism or multicultural education.
One common use of the term refers to the raw fact of cultural diversity: “multicultural education … responds to a multicultural population.”
Another use of the term refers to an ideological awareness of diversity: “[multicultural theorists] have a clear recognition of a pluralistic society.”
Still others go beyond this and understand multicultural as reflecting a specific ideology of inclusion and openness toward “others.”
Perhaps the most common use of this term in the literature is in reference simultaneously to a context of cultural pluralism and an ideology of inclusion or “mutual exchange of and respect for diverse cultures.”
When the term is used to refer to a group of persons (or an organization or institution), it most often refers to the presence of and mutual interaction among diverse persons (in terms of race, class, gender, and so forth) of significant representation in the group. In other words, a few African Americans in a predominantly European American congregation would not make the congregation “multicultural.”
Some, however, do use the term to refer to the mere presence of some non-majority persons somewhere in the designated institution (or group or society), even if there is neither significant interaction nor substantial numerical representation.
Designating a context or ideology of racial pluralism: “Black, White, Asian, Latino/a, Native American persons.” Multicultural generally intends wider diversity, implying recognition also of gender, economic, and political differences.
“Multiracial education” is preferred over multicultural education by some since it conceptually addresses the issue of institutionalized racism more directly.
This list is compiled from a variety of sources by the Office of Racial Justice and Multi-Racial, Multi-Cultural Transformation, United Church of Christ, Cleveland Based Team, Fall 2006 | <urn:uuid:e6971c3b-063e-48e8-88ee-91be194bdb54> | CC-MAIN-2013-20 | http://www.ucc.org/justice/multiracial-multicultural/glossary/m.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368700563008/warc/CC-MAIN-20130516103603-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.925836 | 739 | 3.75 | 4 |
Pediatric Fever Diagnosis
A fever is not a disease, but a symptom. Your child has a fever when the temperature is at or above one of these levels:
- 100.4°F°C) measured rectally
- 100°F (°C) measured orally
- 99°F (°C) measured under the arm
If your child is less than 6 months old, take his/her temperature rectally.
Pediatric fevers can be one of the most challenging symptoms that parents and doctors face. Most fevers are merely the result of minor illnesses, such as colds and viruses. In rare cases, they can be the warning sign of more serious bacterial or viral infections. | <urn:uuid:8a28a2a2-ccde-4651-a425-7d5d4313bc13> | CC-MAIN-2013-20 | http://www.wellstar.org/medical-care/pediatrics/pages/fever-diagnosis.aspx | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368700563008/warc/CC-MAIN-20130516103603-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.927704 | 145 | 3.671875 | 4 |
Analysis and Design of Shallow and Deep Foundations
November 2005, ©2006
This price is valid for United States. Change location to view local pricing and availability.
List of Symbols and Notations.
1. Introduction to Part 1.
1.1 Historical Use of Foundations.
1.2 Kinds of Foundations and their Uses.
Spread Footings and Mats.
1.3 Concepts in Design.
Gain Information of Geology at Site.
Obtain Information on Magnitude and Nature of Loads on Foundation.
Obtain Information on Properties of Soil at Site.
Consideration of Long-term Effects.
Appropriate Attention to Analysis.
Recommendations for Tests of Deep Foundations.
Observe Behavior of Foundation for Completed Structure.
2. Engineering Geology.
2.2 Nature of Soil Affected by Geologic Processes.
Nature of Transported Soil.
Weathering and Residual Soil.
Nature of Soil Affected by Volcanic Processes.
Nature of Glaciated Soil.
2.3 Available Data on Regions in the United States.
2.4 U.S. Geological Survey and State Agencies.
2.5 Examples of Application of Engineering Geology.
2.6 Site Visit.
3. Fundamentals of Soil Mechanics.
3.2 Data Needed to Design Foundations.
Solid and Rock Classification.
Location of the Water Table.
Shear Strength and Density.
Prediction of Changes in Conditions and the Environment.
3.3 Nature of Soil.
Types of Soil and Rock.
Mineralogy of Common Geologic Materials.
Water Content and Void Ratio.
Saturation of Soil.
Atterberg Limits and the Unified Soils Classification System.
3.4 Concept of Effective Stress.
Laboratory Tests for Consolidation of Soils.
Spring and Piston Model of Consolidation.
Determination of Initial Total Stresses.
Calculation of Total and Effective Stresses.
The Role of Effective Stress in Soil Mechanics.
3.5 Analysis of Consolidation and Settlement.
Time Rates of Settlement.
One-Dimensional Consolidation Testing.
The Consolidation Curve.
Calculation of Total Settlement.
Calculation of Settlement due to Consolidation.
Reconstruction of the Field Consolidation Curve.
Effects of Sample Disturbance on Consolidation Properties.
Correlation of Consolidation Indices with Index Tests.
Comments on Accuracy of Settlement Computations.
3.6 Shear Strength of Soils.
Friction Between Two Surfaces in Contact.
Direct Shear Testing.
Triaxial Shear Testing.
Drained Triaxial Tests on Sand.
Triaxial Shear Testing of Saturated Clays.
The SHANSEP Method.
Other Types of Shear Testing for Soils.
Selection of the Appropriate Test Method.
4. Investigation of Subsurface Conditions.
4.2 Methods of Advancing Borings.
Continuous-flight Auger with Hollow Core.
4.3 Methods of Sampling.
Sampling with Thin-Walled Tubes.
Sampling with Thick-Walled Tube.
4.4 In Situ Testing of Soil.
Cone Penetrometer and Piezometer-Cone Penetrometer.
Vane Shear Device.
4.5 Boring Report.
4.6 Subsurface Investigations for Offshore Structures.
5. Principal Types of Foundations.
5.1 Shallow Foundations.
5.2 Deep Foundations.
Driven Piles with Impact Hammer.
5.4 Hybrid Foundation.
6. Designing Stable Foundations.
6.2 Total and Differential Settlement.
6.3 Allowable Settlement of Structures.
Tolerance of Buildings to Settlement.
Exceptional Case of Settlement.
Problems in Proving Settlement.
6.4 Soil Investigations Appropriate to Design.
Soils with Special Characteristics.
6.5 Use of Valid Analytical Methods.
Oil Tank in Norway.
Transcona Elevator in Canada.
Bearing Piles in China.
6.6 Foundations at Unstable Slopes.
Fort Peck Dam.
6.7 Effects of Installation on Quality of Deep Foundations.
6.8 Effects of Installation of Deep Foundations on Nearby Structures.
6.9 Effects of Excavations on Nearby Structures.
6.10 Deleterious Effects of Environment on Foundations.
6.11 Scour of Soil at Foundations.
7. Theories of Bearing Capacity and Settlement.
7.2 Terzaghi's Equations for Bearing Capacity.
7.3 Revised Equations for Bearing Capacity.
7.4 Extended Formulas for Bearing Capacity by J. Brinch Hansen.
Load Inclination Factors.
Base and Ground Inclination.
Passive Earth Pressure.
7.5 Equations for Computing Consolidation Settlement of Shallow.
Foundations on Saturated Clays.
Prediction of Total Settlement due to Loading of Clay Below the Water Table,
Prediction of Time Rate of Settlement due to Loading of Clay Below the Water Table.
8. Principles for the Design of Foundations.
8.2 Standards of Professional Conduct.
8.3 Design Team.
8.4 Codes and Standards.
8.5 Details of Project.
8.6 Factor of Safety.
Selection of Global Factor of Safety.
Selection of Partial Factors of Safety.
8.7 Design Process.
8.8 Specifications and Inspection of Project.
8.9 Observation of Completed Structure.
9. Geotechnical Design of Shallow Foundations.
9.2 Problems with Subsidence.
9.3 Designs to Accommodate Construction.
De-watering During Construction.
Dealing With Nearby Structures.
9.4 Shallow Foundations on Sand.
Immediate Settlement of Shallow Foundations on Sand.
Bearing Capacity of Footings on Sand.
Design of Rafts on Sand.
9.5 Shallow Foundations on Clay.
Settlement from Consolidation.
Immediate Settlement of Shallow Foundations on Clay.
Design of Shallow Foundations on Clay.
Design of Rafts.
9.6 Shallow Foundations Subjected to Vibratory Loading.
9.7 Designs in Special Circumstances.
Design of Shallow Foundations on Collapsible Soil.
Design of Shallow Foundations on Expansive Clay.
Design of Shallow Foundations on Layered Soil.
10. Geotechnical Design of Driven Piles Under Axial Loads.
10.1 Comment on Nature of the Problem.
10.2 Methods of Computation.
Behavior of Axially-Loaded Piles.
Geotechnical Capacity of Axially-Loaded Piles.
10.3 Basic Equation for Computing the Ultimate Geotechnical Capacity of a Single Pile.
Revised Lambda Method.
U.S. Army Corps Method.
10.4 Analyzing the Load-Settlement Relationship of an Axially Loaded Pile.
Methods of Analyses.
Interpretation of Load-Settlement Curves.
10.5 Quality of Results Based on the Proposed Computation Method.
10.6 Example Problems.
10.7 Analysis of Pile Driving.
Reasons for the Problems with Dynamic Formulas.
Dynamic Analysis by Wave Equation.
Effects of Pile Driving.
Effects of Time after Pile Driving with No Load.
11. Geotechnical Design of Drilled Shafts Under Axial Loading.
11.2 Presentation of FHWA Design Procedure.
11.3 Strength and Serviceability Requirements.
11.4 Design Criteria.
Applicability and Deviations.
11.5 General Computations for Axial Capacity of Individual Drilled Shafts.
11.6 Design Equations for Axial Capacity in Compression and in Uplift.
Description of Soil and Rock for Axial Capacity Computations.
Design for Axial Capacity in Cohesive Soils.
Design for Axial Capacity in Granular Soils.
Design for Axial Capacity in Cohesive Intermediate Geomaterials and Jointed Rock.
Design for Axial Capacity in Cohesionless Geomaterials
Design for Axial Capacity in Massive Rock.
Addition of Side Resistance and End Bearing in Rock.
Commentary on Design for Axial Capacity in Karst.
Comparison of Results from Theory and Experiment.
12. Fundamental Concepts Regarding Deep Foundations Under Lateral Loading.
Description of the Problem.
Occurrence of Piles Under Lateral Loading.
12.2 Derivation of the Differential Equation.
Solution of reduced form of differential equation.
12.3 Response of Soil to Lateral Loading.
12.4 Effect of Nature of Loading on Response of Soil.
12.5 Method of Analysis for Introductory Solutions for a Single Pile.
12.6 Example Solution Using Non-dimensional Charts for Analysis of a Single Pile.
13. Analysis of Individual Deep Foundations Under Axial Loading Using t-z Model.
13.1 Short-term Settlement and Uplift.
Settlement and Uplift Movements.
Finite Difference Equations.
Load-Transfer Curves for Side Resistance in Cohesive Soil.
Load-Transfer Curves for End Bearing in Cohesive Soil.
Load-Transfer Curves for Side Resistance in Cohesionless Soil.
Load-Transfer Curves for End Bearing in Cohesionless Soil.
Load-Transfer Curves for Cohesionless Intermediated Geomaterials.
13.2 Design for Vertical Ground Movements Due to Downdrag or Expansive Uplift.
Downward Movements Due to Downdrag.
Upward Movement Due to Expansive Uplift.
14. Analysis and Design by Computer of Piles Subjected to Lateral Loading.
14.1 Nature of the Comprehensive Problem.
14.2 Differential Equation for Comprehensive Solution.
14.3 Recommendations for p-y Curves for Soil and Rock.
Recommendations for p-y Curves for Clays.
Recommendations for p-y Curves for Sands.
Modifications to p-y Curves for Sloping Ground.
Modifications for Raked (Battered Piles).
Recommendations for p-y Curves for Rock.
14.4 Solution of Differential Equation by Computer.
Formula of Equation by Finite Differences.
Equations for Boundary Conditions for Useful Solutions.
14.5 Implementation of Computer Code.
Selection of Length Increment.
Safe Penetration of Pile With No Axial Load.
Buckling of a Pipe Extending Above Ground Line.
Steel Pile Supporting a Retaining Wall.
Drilled Shaft Supporting an Overhead Structure.
15. Analysis of Pile Groups.
15.2 Distribution of Load to Piles in a Group, the Two-Dimensional Problem.
Model of the Problem.
Detailed Step-by-Step Solution Procedure.
15.3 Modification of p-y Curves for Battered Piles.
15.4 Example Solution Showing Distribution of Load to Piles in a Two-Dimensional Group.
Solution by Hand Computations.
15.5 Efficiency of Piles in Groups Under Lateral Loading.
Modifying Lateral Resistance of Closely Spaced Piles.
Customary Methods of Adjusting Lateral Resistance for Close Spacing.
Adjusting for Close Spacing under Lateral Loading by Modified p-y Curves.
15.6 Efficiency of Piles in Groups Under Axial Loading.
Efficiency of Piles in a Group in Cohesionless Soils.
Efficiency of Piles in a Group in Cohesive Soils.
List of All References. | <urn:uuid:c67aed8d-446c-46a4-af74-ad361104e1a5> | CC-MAIN-2013-20 | http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471431591,subjectCd-CE20,descCd-tableOfContents.html?filter=TEXTBOOK | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368700563008/warc/CC-MAIN-20130516103603-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.720424 | 2,561 | 3.59375 | 4 |
<< back to Pacific Northwest projects
Partners for Wildlife
RAPTOR ECOLOGY OF THE SHRUB-STEPPE
The Raptor Ecology of the Shrub-Steppe project focused for several years on identifying and tracking the native ferruginous hawk. Through this project, the migration routes of these birds were determined for the first time.
Raptor Ecology of the Shrub-Steppe is working to save:
Ferruginous Hawk (Buteo regalis)
Often mistaken for an eagle due to its size, proportions and behavior. The female is larger than the male, but there is some overlap between small females and large males in size. Length ranges from 20 to 26 inches (51 to 66 cm), wingspan from 48 to 60 inches (120 to 150 cm), and weight from 2.2 to 4.5 pounds (1,000 to 2,000 g). Adults have long broad wings and a broad gray, rusty or white tail. The legs are feathered to the talons, like the Rough-legged Hawk.
Golden Eagle (Aquila chrysaetos)
Golden eagles are dark brown, with lighter golden-brown plumage on their heads and necks. The wingspan averages over 2 m (7 ft) and up to 1 m (3 ft) in body length. They are extremely swift, and can dive upon their quarry at speeds of more than 150 miles (241 kilometers) per hour. Golden eagle pairs maintain territories that may be as large as 60 square miles (155 square kilometers). They are monogamous and may remain with their mate for several years or possibly for life nesting in high places including cliffs, trees, or telephone poles. They build huge nests to which they may return for several breeding years. Females lay from one to four eggs, and both parents incubate them for 40 to 45 days. Typically, one or two young survive to fledge in about three months.
Shrub-steppe is a type of low rainfall natural grassland. Shrub-steppes are distinguishable from deserts, which are too dry to support a noticeable cover of perennial grasses or other shrubs, while the shrub-steppe has sufficient moisture levels to support a cover of perennial grasses and/or shrubs. Rainfall is less than 180 mm or 7" per year.
The Douglas Creek area in Eastern Washington is prime shrub-steppe habitat that support ferruginous and other species of hawk.
Critical threats to wildlife:
GET THE LATEST NEWS FROM THE FIELD
NORTHWEST NATIVE SPECIES RECOVERY PROJECTS
Woodland Park Zoo’s expertise in captive rearing, captive breeding and research plays an essential role within the Pacific Northwest conservation community. WPZ collaborates with other zoos and aquariums on these and other projects as a member of the Northwest Zoo and Aquarium Alliance.
Member of the | <urn:uuid:4d9296ef-7f99-414b-8236-8cb6f41f6535> | CC-MAIN-2013-20 | http://www.zoo.org/page.aspx?pid=1997 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368700563008/warc/CC-MAIN-20130516103603-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.94568 | 602 | 3.5 | 4 |
Mark Fahnestock of the University of Maryland studied two decades of satellite images of the area and found a key correlation between "ponds" of melted ice and the breakup of the Larsen Ice Shelf. The ice broke up the most during years with a lot of melting.
In 1995, when a 775-square-mile chunk of the ice shelf broke off during a violent storm, the "melt season" lasted 80 days, which was 20 days longer than normal, Fahnestock found.
So what appears to be happening is that rising summertime temperatures cause surface ice to melt, flooding cracks and wedging apart the ice. All it takes is a storm, or a nudge from a drifting chunk of ice, to break off a piece.
Hemming in the Continent
The loss of the Larsen shelf in itself is not all that important, unless you happen to be aboard a ship that has to dodge icebergs in the area, but the finding holds profound implications for the rest of Antarctica.
Researchers at Pennsylvania State University, for example, have shown that the huge shelves of floating ice along Antarctica's coast serve a very useful purpose. In effect, they hold back the glaciers on the mainland, providing a "braking system" that keeps the glaciers from sliding into the sea.
That hasn't been much of a problem along the peninsula, because the glaciers there are wedged in mountain valleys and even with the loss of the braking system, it's hard for them to move very fast. And they are smaller glaciers, at least for Antarctica, so their contribution to sea level rise would be inconsequential, Scambos says.
Not too far away, however, is the Ross Ice Shelf, a humongous chunk of ice that holds back giant glaciers that rest on mud. If the Ross were to disintegrate, those glaciers could slide into the sea, although that could take several decades.
Scientists estimate that if the landlocked ice in just the Western Hemisphere of Antarctica were to be released into the ocean, the seas would rise about 15 feet around the world.
What are the chances of that happening?
Drip by Drip
If the Ross experiences a summertime warming trend over the next 50 years equal to the warming of the Larsen over the last half century, it could also disintegrate. And, Scambos says, we're talking a couple of degrees, not a heat wave.
Of course, that might not happen. No one knows yet exactly how much warmer Antarctica is likely to get over the next few decades. But one thing is clear. It's changing.
"There's something fundamentally different about climate now than over the last several centuries," Scambos says. "The Larsen Ice Shelf had been there for several centuries," and it broke up almost overnight, geologically speaking.
And other areas of Antarctica "are closer than we thought to undergoing the same thing," he adds.
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska. | <urn:uuid:67c52c7d-0340-4f12-be39-3653228c6296> | CC-MAIN-2013-20 | http://abcnews.go.com/Technology/story?id=99055&page=2 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.961582 | 641 | 3.90625 | 4 |
Wind is the oldest form of usable energy. It was first used by Egyptians 5,000 years ago to power their ships, and was later adapted in windmills used to grind wheat and other grains by the Persians in the 7th century. In the 12th century, the Dutch modified and improved upon the windmill design. Like old-fashioned windmills, today’s wind turbines use blades to collect the wind’s kinetic energy. Wind turbines work because the wind flows over the airfoil shaped blades creating lift, like the effect on airplane wings, which causes them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity.
The size of wind turbines varies widely. While small turbines used to power a single home or business may have a capacity of less than 5 kW, some large commercial sized turbines may have a capacity of 5,000 kW, or 5 MW. Larger turbines are often grouped together into wind farms that provide power to the local electrical grid.
Wind Energy in Alaska
Alaska has abundant wind resources suitable for development, mostly located in the western and coastal portions of the state. The availability of wind resources in combination with the high cost of diesel electricity generation in much of rural Alaska makes wind power an economical and clean alternative to traditional fossil fuels. A typical 1000-kW wind turbine can displace about 17,800 gallons of diesel fuel per year, a savings of nearly $55,000 to an electric utility paying $3.10/gallon for diesel fuel. The largest areas of class 7 (superior) wind power in the United States are located in Alaska. Much of coastal Alaska has “good” or “excellent” wind resources.
Development of wind energy resources in Alaskan villages started over a decade ago. Kotzebue Electric Association (KEA) installed three wind turbines in 1997. Since then, the utility has added 11 more turbines that produce up to 950 kW, about 7% of the coop’s annual electricity consumption. KEA hopes eventually to expand this generating potential to 2-4 MW, enough to power Kotzebue during peak load times and displace 1.4 million gallons of diesel annually. The Alaska Village Electric Cooperative (AVEC) produces 1.36 MW of energy with 17 wind turbines located in the villages of Selawik, Hooper Bay, Wales, Toksook Bay, Savoonga, and Kasigluk. Over 20% of annual electricity is produced by wind power in the villages of Kasigluk and Toksook Bay, and AVEC estimates that 30% of electricity demand in these communities could eventually be produced from wind. AVEC plans to install a total of 1.2 MW of additional generating capacity in the villages of Toksook Bay, Chevak, Mekoryuk, Quinhagak and Gambell by 2010. The Chaninik Wind Group is working to install 450 kW of wind capacity in each of the villages of Kongiganak, Kwigillingok, Tuntutuliak, and Kipnuk in 2009. In Kodiak, the Kodiak Electrical Association is installing three 1.5 MW turbines at Pillar Mountain, with generation expected to begin in the fall of 2009. The Tanadgusix Corporation (TDX) on St. Paul Island in the Bering Sea has also been active in developing wind-diesel hybrid generation technology in rural Alaska. TDX built a hybrid system on St. Paul, reducing electricity costs from $0.49 to $0.12 per kWh. Plans are in the works to build similar facilities in the Aleutian villages of Sand Point and Nikolski.
On the Railbelt, several of the major utilities are examining wind power as a way to diversify future sources of energy and hedge against rising natural gas prices. Construction of Anchorage’s first commercial-scale wind farm is underway on Fire Island with plans for the turbines to begin producing power in late 2012. The project is owned by Fire Island Wind LLC, a subsidiary of CIRI, and will use 11 turbines to generate 17.6 MW of electricity, or enough to power about 6,000 homes. Chugach Electric Association has agreed to purchase the wind power for 25 years to supply about 4% of the utility’s load. Golden Valley Electric Association has also made substantial progress towards developing the roughly 25 MW Eva Creek Wind project located near existing transmission lines north of Healy. Together, Fire Island and Eva Creek could provide approximately 5% of the Railbelt’s electrical energy.
Renewable Energy Atlas of Alaska 2009
Energy Information Administration
National Renewable Energy Laboratory
Kotzebue Electric Association
Alaska Village Electric Cooperative
Alaska Center for Economic Development | <urn:uuid:9f1738aa-5a5f-4cbf-a80a-53e2d671daa7> | CC-MAIN-2013-20 | http://alaskarenewableenergy.org/renewable-energy/alaskas-resources/wind/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.931404 | 980 | 3.796875 | 4 |
Shelly Hellums and Mindy Hutton
Kilby Laboratory School, Lauderdale County
L.E. Willson Elementary, Sheffield City/ Alabama Virtual Library
In the first of the series, this podcast provides a tutorial on how to use the basic search function in the Kids InfoBits database of the Alabama Virtual Library. Items discussed include an overview of the categories within the database, narrowing search results, and using information to create products in the elementary classroom. An example of a project-based assessment is included within the podcast.
Content Areas: Science, Technology Education, Professional Development
Alabama Course of Study Alignments and/or Professional Development Standard Alignments:
[TC2] (3-5) 2: Use various technology applications, including word processing and multimedia software.
[TC2] (3-5) 8: Collect information from a variety of digital sources.
[TC2] (3-5) 9: Use technology tools to organize, interpret, and display data.
[TC2] (3-5) 10: Use digital environments to collaborate and communicate.
AQTS_1.A.2: Academic Discipline(s) [Knowledge of ways to organize and present content so that it is meaningful and engaging to all learners whom they teach (pedagogical content knowledge).]
AQTS_1.A.5: Academic Discipline(s) [Ability to help students make connections across the curriculum in order to promote retention and transfer of knowledge to real-life settings.]
AQTS_1.B.3: Curriculum [Ability to select content and appropriately design and develop instructional activities to address the scope and sequence of the curriculum.]
AQTS_3.A.3: Oral and Written Communications [Knowledge of media communication technologies that enrich learning opportunities.]
AQTS_3.D.1: Technology [Knowledge of available and emerging technologies that support the learning of all
AQTS_3.D.2: Technology [Knowledge of the wide range of technologies that support and enhance instruction,
including classroom and school resources as well as distance learning and online learning
AQTS_3.D.3: Technology [Ability to integrate technology into the teaching of all content areas.]
AQTS_3.D.4: Technology [Ability to facilitate students' individual and collaborative use of technology, including
classroom resources as well as distance and online learning opportunities when available
AQTS_3.D.6: Technology [Ability to evaluate students' technology proficiency and students' technology-based
products within content areas.] | <urn:uuid:13a17921-753b-480d-a6fb-a6bae6c2b356> | CC-MAIN-2013-20 | http://alex.state.al.us/podcast_view.php?podcast_id=892 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.873036 | 541 | 3.546875 | 4 |
As many alumni probably know, an exoplanet is a planet outside of our solar system that orbits a star other than the sun. Speculation about exoplanets has existed for centuries, with one of the earliest known references dating to the sixteenth century when Giordano Bruno, and Italian philosopher, put forward the view that fixed stars could be similar to our sun and likewise accompanied by their own planets. In 1988 the first exoplanet was detected.
Today, astronomers have confirmed detection of 529 such planets, and more than 1200 additional planets await confirmation. The vast majority of these exoplanet candidates were discovered as part of NASA’s Kepler mission, which launched in 2009 with the goal of locating Earth-size planets in Earth-like orbit around sun-like stars. MIT’s Sara Seager, the Ellen Swallow Richards Professor of Planetary Science and Professor of Physics, is on the Kepler team, which recently released a slew of data to the public. Seager gave a talk about exoplanets on February 9 and touched on several of the points below.
10 Things You May Not Know About Exoplanets
(as of February 2011)
- The Kepler space telescope detects exoplanet candidates by looking at one large area of the sky and measuring the brightness of more than 100,000 stars every 30 minutes. Tiny “winks” in star brightness (which can last anywhere from an hour to half a day) occur when a planet passes in front of the star. This is called the “transit method” of detection. See Occultation-Graph animation (QuickTime, 1 MB).
- Exoplanets are confirmed by observing several transits that have the same dip in star light, time to transit the star, and amount of time between successive transits. It takes about 1000 people-hours to confirm an exoplanet.
- Before Kepler, there were a total of about 520 known exoplanets, but last year the Kepler team announced 700 new exoplanet candidates, and in early February 2011 they unveiled 500 more.
- Of the 1235 exoplanet candidates identified by Kepler to-date, 54 are in the habitable zone (the region where water can exist as a liquid on the surface of a planet), and five are near Earth-sized. The five near Earth-sized planets orbit small, low-luminosity stars that are very different from our sun. The remaining 49 habitable zone candidates range from super-Earth size (up to twice the size of Earth) to larger than Jupiter.
- About 60 to 80 percent of the 1200 Kepler candidates are considered likely to be real planets.
- Professor Seager calls Kepler-11, which was revealed in the recent batch of Kepler findings, “the most fascinating planetary system ever discovered.” Kepler-11 has six confirmed transiting planets, five of which are so close to one another that they gravitationally perturb each other’s orbits, enabling scientists to calculate each of the planets’ masses–and with additional Kepler data–their densities. Seager says the planets’ densities are so low that they probably have low-density material like gas or ice in layers above any rocky/iron interior, making the Kepler-11 planets “unlike any planet in our own solar system.” View an animation of Kepler-11 below:
Excited about exoplanets?? Check back tomorrow for a post about how to get involved. | <urn:uuid:3b2dad75-24bf-449a-a3c6-cb42f9d968b8> | CC-MAIN-2013-20 | http://alum.mit.edu/pages/sliceofmit/2011/02/15/exoplanets/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.949861 | 712 | 3.96875 | 4 |
The brains of people with Alzheimer’s contain large numbers of plaques and tangles. Plaques are formed from beta-amyloid. Tangles are made of a protein called tau. Like beta-amyloid, tangles can also damage the brain and thus contribute to the devastating loss of mental function in Alzheimer’s disease. Scientists have known for a while that tangles are caused when the tau protein does not fold properly. All proteins need to fold to have normal function. When a protein does not fold properly, it not only loses its own function, but also may damage many other proteins in cells, especially in the brain. Fisher Center scientists recently discovered that they could prevent the formation of tangles in a model of Alzheimer’s disease by supplying a drug that blocks a type of protein known as a “chaperone” or “stress protein.” This could lead to treatments that prevent much of the devastating damage to brain cells that occurs in Alzheimer’s. Such treatment might be applied alongside an anti-amyloid treatment and this combination may turn out to be especially beneficial. | <urn:uuid:629ecc20-11c3-4bee-acd7-e59f3c79935c> | CC-MAIN-2013-20 | http://alzinfo.org/08/alzheimers/recruiting-stress-proteins-to-clean-up-tangles-in-the-brain | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.957464 | 232 | 3.9375 | 4 |
We have a guest post from Martin Still. Martin is Deputy Science Team Lead and Guest Observer Office Director for Kepler. He’s writing today to tell you about an interesting class of objects you might encounter when classifying Kepler light curves
Dwarf novae are binary stars consisting of a white dwarf and main sequence companion. The binary orbit of period a few hours is small enough that the outer atmosphere of the main sequence star is being stripped through gravitational influence by the white dwarf, and gas is falling in a steady stream towards the surface of the white dwarf. The light from the binary stars is dominated not by the stellar components but the accreting material configured around the white dwarf within an accretion disk. The brightness of the accretion disk is coupled strongly to the temperature and density of the disk. Brightness changes over the timescales of a few days and several magnitudes indicate changes in the density and temperature of the disk. Coherent oscillations in the light curves of dwarf novae on timescales of a few hours indicate the orbital period of the binary and tidally-driven distortions in the accretion disk. To identify dwarf novae, look for targets that brighten by an order of magnitude or more over a few days and decay on a similar timescale. Coherent modulation on periods of a few hours are also expected, but not essential for characterization as a dwarf nova. 16 dwarf novae are currently known in the Kepler field, perhaps several hundred more are suspected to reside there. Some of them will be faint, blended background sources behind brighter Kepler targets. Dwarf novae are scientifically important because they are the cleanest objects in the galaxy for studying accretion disks – those structures that surround e.g. active galactic nuclei, cataclysmic variables and symbiotic stars. Planets around stars form from similar disks around proto-stars. Without a detailed understanding of accretion disks, the evolution and structure of the universe on many scales cannot be understood.
If you spot light curves like these, please post them in Talk here.
Here’s an example of a dwarf novae light curve, you can see the huge brightness humps are when the outbursts are occuring
or you might spot in one of the light curves you’re reviewing on the main Planet Hunters site something like this: | <urn:uuid:48666973-b705-4e92-88cd-6b63d651afd4> | CC-MAIN-2013-20 | http://blog.planethunters.org/2012/04/07/dwarf-novae/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.933607 | 474 | 3.515625 | 4 |
Lichens are composite organisms consisting of a fungus growing symbiotically with either a green alga or a cyanobacterium. They have distinctive reproductive structures that release spores. They commonly encrust rocks, branches, or anything else that does not move fast!
Some 1700 different kinds of lichen occur in New Zealand (Galloway 2007).
Galloway DJ (2007) Flora of New Zealand. Lichens. Volume Two. Manaaki Whenua Press, Lincoln. | <urn:uuid:cd0ec742-895b-4201-9e2f-5c1c1e81a80f> | CC-MAIN-2013-20 | http://collections.tepapa.govt.nz/theme.aspx?irn=2098 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.856559 | 98 | 3.515625 | 4 |
[A:] I sure can. There are quite a few definitions relating to cost. We will consider the following seven terms: Marginal Cost, Total Cost, Fixed Cost, Total Variable Cost, Average Total Cost, Average Fixed Cost, and Average Variable Cost. When asked to compute these seven figures on an assignment or on a test, the data you need is likely to come in one of three forms.
- In a table which gives you total cost and quantity produced.
- A linear equation relating total cost (TC) and quantity produced (Q). This would be an equation like TC = 400Q + 20, or TC = 50 + 6Q.
- A non-linear equation relating total cost (TC) and quantity produced (Q). This would be an equation like TC = 34Q3 – 24Q + 9 or TC = Q – log(Q).
We will look at all seven of these terms using the data on the bottom of this article. You may want to print this page out as a reference so you don't have to keep scrolling back and forth. Lets get started!
Marginal CostMarginal Cost is the cost a company incurs when producing one more good. Suppose we're producing two goods, and we would like to know how much costs would increase if we increase production to three goods. This difference is the marginal cost of going from two to three. It can be calculated by:
Marginal Cost(2 to 3) = Total Cost of Producing 3 – Total Cost of Producing 2.
Looking at our data, it costs 600 to produce three goods and 390 to produce two goods. The difference between the two figures is 210, so that is our marginal cost.
Sometimes your chart will give you the marginal cost, and you'll need to figure out the total cost. We might have that the cost of producing one good is 250, and the marginal cost of producing another good is 140. Then we can figure out the total cost of producing two goods by:
Total Cost of Producing 2 = Total Cost of Producing 1 + Marginal Cost(1 to 2)
In our case the total cost would be 250 + 140 = 390. So the total cost of producing two goods is 390.
Total CostThe total cost is simply all the costs incurred in producing a certain number of goods. That question is easy to answer here, as we can just read it off of our chart. So the total cost of producing three goods is 600 and the total cost of producing five goods is 1200. If you're given marginal cost data instead of total cost data, you can compute the total by the example given in the marginal cost section.
Fixed CostFixed costs are the costs that are independent of the number of goods you produce, or more simply the costs you incur when you do not produce any goods. We see from our chart that when we produce zero goods our costs are 130. So our fixed cost of production is 130.
Total Variable CostsThese are just the opposite of fixed costs; these are the costs that do change when we produce more. We calculate the total variable cost of producing 4 units by:
Total Variable Cost of Producing 4 units = Total Cost of Producing 4 Units – Total Cost of Producing 0 units.
In our case it costs us 840 to produce 4 units and 130 to produce 0. Then our total variable costs when we produce 4 units is 710 since 810-130=710. Similarly our total variable costs when we produce 5 units is 1070.
Average Total CostsOur average total cost is our fixed costs over the number of units we produce. So if we produce five units our formula is:
Average Total Cost of Producing 5 = Total Cost of Producing 5 units / Number of Units
With our data we have an average total cost of producing five units of 200, as the total cost of producing five units is 1200 and 1200/5 = 240. The average total cost of producing four units is 210 as 840/4 = 210.
Average Fixed CostsOur average fixed cost is our fixed costs over the number of units we produce, given by the formula:
Average Fixed Cost = Fixed Costs / Number of Units
So our average fixed cost of producing five units is our total fixed costs (130), divided by the number of units (5), which gives us an average fixed cost of producing five units of 26 (26 = 130/5). Similarly the average fixed cost of producing two units is 65 as 130/2 = 65.
Average Variable CostsAs you might have guessed, our formula for average variable costs is:
Average Variable Cost = Total Variable Costs / Number of Units
We saw that the total variable cost of producing four units is 710 and 870 for six units. Then the average variable cost of producing four units is 177.5 (710/4) and the AVC of producing five units is 214 (1070/5).
Be sure to continue to section 2 where we look at calculating all seven cost measures when given a linear equation.
Total Cost and Quantity Data | <urn:uuid:a0c394a4-93ba-4724-8a85-c8c62e426d2d> | CC-MAIN-2013-20 | http://economics.about.com/cs/studentresources/a/costs.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.927086 | 1,034 | 4.40625 | 4 |
It wasn’t long ago that wolves were thought to be found only in Europe, Asia, and North America.
However, there were always wolf-like golden jackals that had scientists perplexed for many years.
Earlier texts listed these animals as Canis lupus lupaster, usually called the Egyptian wolf, but by the late twentieth century, it was assumed that they were nothing more than wolf-like golden jackals. The scientific name for this wolf-like golden jackal was Canis aureus lupaster.
Then, in the January of last year, a study that compared the mitochondrial DNA of wolves and golden jackals, including these wolfish ones, revealed that the wolfish jackals were not golden jackals at all.
Instead, it was found that they represented a primitive mitochondrial lineage within Canis lupus.
So they were wolves after all.
However, that study also revealed that these wolves were also found in Ethiopia. Not to be confused with the critically endangered Ethiopian wolf (Canis simensis), the African wolves were an early branch of the Canis lupus species that invaded Africa and then became genetically isolated from the main wolf lineages of Eurasia and North America. This exact same issue exists with Himalayan and certain wolves from the Indian subcontinent. Their mitochondrial lineages are very old.
The discovery of Canis lupus wolves in Ethiopia was a bit of a shock, and the question that everyone want to know was exactly how extensive the African wolf’s range was. | <urn:uuid:2212c396-9ae8-49b5-963d-0392240d8170> | CC-MAIN-2013-20 | http://forteanzoology.blogspot.com/2012/08/retrieverman-on-african-wolves.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.981071 | 318 | 3.828125 | 4 |
The Early Han Dynasty
206 BCE - 9 AD
From the turbulent Ch'in dynasty a rebel leader, Liu Pang, arose to seize control of the former Ch'in empire. He proclaimed himself emperor in 206 BCE. He established the Han dynasty which would become the most durable dynasty of the imperial age. The Han empire was established using what the Ch'in had already set up. The only difference is that some of the policies were modified, especially those that had caused the Ch'in collapse. Taxes were also reduced drastically, while the government played a smaller role in the economic policies.
One of important contributions of the Han was the establishment of Confucianism as the official ideaology over Legalism. The Confucianism was not the pure studies of Confucius, but a conglomeration of various other philosphies and superstitions to augment the complex and sparse teachings of Confucius. This changed the way that the empire was run. Before, emperors appointed people to positions regardless of thier competence. Now, the emperors chose the people they thought were the best suited for the job based on merit. Written examinations were used to identify the best qualified people for the job. In the 2nd cnetury BCE, an imperial university was established to teach students the five classics of the Confucian school to prepare them to become bureaucrats.
The height of the Han empire was under the rule of Emperor Wu Ti, who ruled the Han empire from 140 to 87 BCE. Emperor Wu wanted to expand his kingdom and did, but at a price. The once abundent coffers of the Han kingdom, collected in the days when the government was hands off regarding the economy, were empty. This led to the re-establishing of the legalist philosophy; taxes and old policies were reinstated. This did not go well with the people and large land owners opposed the centeral government by refusing to pay taxes. The government overlooked the large land cases and over-taxed the peasants. The peasants did not like the change and a revolt ensued.
Go to Xin dynasty
Go Back to Dynasty Shelf | <urn:uuid:c7d30c07-b135-45ea-8536-402b7897a5e5> | CC-MAIN-2013-20 | http://library.thinkquest.org/12255/library/dynasty/earlyHan.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.978549 | 428 | 4.03125 | 4 |
History of Social Work
Social workers have played an important role in the advancement of human civilization since long ago. They uphold social justice by reducing inequality and promoting human rights. Social workers try to improve the quality of life of unfortunate people in the society and help them realize their true potential. This is done through counseling, mediating between the needy and charitable organizations or the government, and other activities. Social work helps to solve a lot of problems in the society, and it contributes significantly towards the cultural and moral advancement of humankind.
Origins and Modern History of Social Work
All major religions encourage people to help the poor, and some of these religions were formed thousands of years ago. Therefore, it can be said that social work originated in the ancient times, when human beings started to perform charity work. In the western world, the first documented instance of organized social work occurred during the 3rd century, right after the Christian Church was legalized by Roman Emperor Constantine I. The church set up hospitals, poorhouses, orphanages, and homes for the elderly, and these establishments received grants from the Roman Empire. By the 6th century, the church had developed an elaborate system for distributing food and other consumables to the poor. Later on, it would encourage the European public to offer direct relief to the unfortunate.
During the 19th century, the industrial revolution led to a lot of social problems in England and the United States, including poverty, diseases, mental disorders, prostitution, and others. As such, there was a great need for social work. Churches and governments established effective systems and laws to provide assistance for the needy, and many individuals started to form groups and organizations to perform social work.
Jane Addams, Mother of Social Work
Jane Addams was one of the first social workers in the US. When she was 27 years old, she visited the Toynbee Hall settlement house in London, and she developed an aspiration to open a similar house in Chicago. In 1889, she partnered with her friend Ellen Starr to set up a settlement house called the Hull-House. They gave speeches about the social problems that were plaguing their neighborhood, raised funds, and encouraged young women to become volunteer social workers. After two years, the Hull-House was providing assistance to around 2,000 people every week. As she became more famous in Chicago, she began to take on greater civic responsibilities, such as founding a school of philanthropy, conducting investigations on social problems, and campaigning for peace. For her extraordinary efforts in social work, Jane Addams was awarded the Nobel Peace Prize in the year 1931.
Social Work in America
Before the 18th century, public health was the only form of social welfare that was available in the US. During the early part of the next century, almhouses were set up in a number of major cities around the country, and these almhouses were transformed into hospitals later on. Mass migrations to the US in the 19th century resulted in serious social problems, and this called for a more efficient way to provide aid to the unfortunate. The establishment of settlement houses and social work departments sparked the beginning of modern social work in the US. By 1911, there were more than 40 social work departments in 14 cities, and the number grew to 200 in 1913. Now, social work in the US is regarded as one of the most efficient and effective in the world.
Social Work in the UK
Social upheaval and mass migration contributed significantly to the evolution of social work in the UK. The populations of cities were increasing dramatically during the industrial revolution, and many people were afflicted by poverty and diseases. The UK government responded by offering free treatment in hospitals, and hospital almoners were recruited to help in the treatment of patients. These almoners were regarded as social workers, and their roles began to include other social responsibilities in the following years.
Social work has come a long way to become an important profession in the modern society. The scope of responsibilities of social work has become wider over the years, and social workers require more extensive training to perform their duties effectively. As social problems grow in the modern society, social work will continue to gain importance around the world.
Social Work Resources
To learn more about the history and advances in social work, visit these links:
- Social Work History Station: A web page that offers extensive information on the history of social work.
- Evolution of Social Work: A timeline that reveals the evolution of social work throughout history.
- Biography of Jane Addams: Comprehensive account of the life and works of Jane Addams.
- Pioneer Social Workers Database: Huge collection of biographies of important social workers in history.
- Social Work History Resources: Links to websites that provide information on social work history.
If your interested in learning more about Social Work and becoming a Social Worker you may consider a Social Work Degree:
Social Work Degrees – A listing of the various social work degrees available
Online MSW – What elements you should examine when looking for a Online MSW.
Masters Degree Social Work – A degree program for those who do not have their bachelors in social work.
Master of Social Work – A program overview of UNE’s Master of Social Work.
Online MSW Program – A advanced program that enables you to choose two unique concentrations.
Social Worker Degrees - The various degree options for social workers.
Online MSW Degree FAQS – A listing of the frequently asked questions related to an Online MSW Degree.
Masters Degree in Social Work – Why you should consider a masters degree in social work.
POSTED BY: ec_admin - May 12th, 2010 at 03:46pm ( 0 ) | <urn:uuid:37417978-6b97-4f48-9917-05c1e9e4f610> | CC-MAIN-2013-20 | http://mastersinsocialwork.une.edu/history-of-social-work/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.966481 | 1,163 | 3.6875 | 4 |
A key way of understanding our climate and making projections about how it may change in the future is to use climate models.
These are essentially simulations of the Earth’s climate system. They are made up of millions of lines of computer code which represent the physical processes which govern our atmosphere and oceans.
Supercomputers then run the code using observations of modern day climate, with the models able to recreate the past (hindcasting) or give projections of the future (forecasting).
Looking at the past is important for understanding historical changes and influences on climate, and it also allows scientists to gauge how accurate the models are (by comparing model output to reality).
Looking at the future enables researchers to see how things might change given various different scenarios – such as changing levels of greenhouse gases.
The Met Office uses models to look at many different timescales and to study different aspects of the Earth’s climate system.
You can find out more about how climate models work in our YouTube video. | <urn:uuid:2bf2b274-05a5-4916-bdc1-5ac3f42ab22a> | CC-MAIN-2013-20 | http://metofficenews.wordpress.com/2012/05/15/what-are-climate-models/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.924991 | 205 | 4.21875 | 4 |
A Reference Resource
The American Franchise
During Monroe's presidency, five new states had joined the Union: Mississippi (1817), Illinois (1818), Alabama (1819), Maine (1820), and Missouri (1821). Twenty-five percent of the American population was living west of the Appalachians by 1820. According to the Land Act of 1820, farmers could buy eighty acres at $1.25 per acre with a down-payment of $100 in cash. At such prices, nearly 3.5 million acres of land were purchased in 1820 alone, although not all of these sales reflected actual settlement. Land speculation in the West was uncontrolled, as wealthy investors bought giant tracts for resale to farmers and migrants. For these western settlers, the major political issues reflected their need for easy credit to clear the land, good transportation routes to move their products to market, debt relief, and cheap manufactured goods for them to consume.
Although the new states gave a western slant to American politics, most of the settlers still tended to identify with the regions from which they had recently migrated. Importantly, most Americans still thought of themselves as Americans first. With this strongly nationalist temperament, most Americans were swept up in the changes in transportation that began to revolutionize travel and the movement of goods, as well as by the effects of the so-called market revolution. By 1820, there were sixty steamboats on the Mississippi River alone; dozens more operated on the Hudson River and the Great Lakes. James Monroe was the first President to travel on a steamboat, which he did in 1817. That year, Monroe's first as President, the New York legislature authorized funding to build a canal linking the Hudson River with Lake Erie, thus opening a continuous water route connecting the Northwest to New York City. The Erie Canal, a giant ditch stretching 364 miles from Albany to Buffalo that was completed in 1825, was built by thousands of Irish immigrants, local farm boys, and convict laborers.
In New England, a new system of factories, using steam-driven looms, began employing thousands of local farm girls in the production of cloth. In the New England countryside, moreover, farmers began raising livestock and consuming store-bought goods such as sugar, salt, coffee, sacks of western flour, silverware, and dishes. Urban centers of industry were also being transformed. New York City, for example, became the center of a national market of ready-made clothes in the 1820s. The city's manufacturing success was built upon the new supplies of cheap cloth, an expanding supply of female labor, and the emergence of southern and western markets that were accessible via coastal and overland trade routes. Thousands of women worked in sewing to crudely assemble "Negro cottons" for shipment to southern planters as slave clothing. By 1825, shoemakers in Massachusetts manufactured barrels of shoes—uniform in size—for shipment to the slave South.
Below the Mason-Dixon surveyor's line, which separated the borders of the slave South from the North, the invention of the cotton gin in 1793 had revolutionized southern agriculture. By the mid-1820s, cotton and plantation slavery were beginning to dominate the most fertile lands stretching from Georgia to Mississippi. Wealthy planters lived in richly furnished plantation mansions and had begun to create a lifestyle of white mastery over black slaves that shaped every aspect of southern life.
As the market revolution transformed subsistence farmers into commercial farmers who specialized in crops for sale, the average size of the American family began to decline from 6.4 children to 4.9 children; this was especially noticeable in the more commercialized farming areas of the North. Also, women began to labor more intensively in new kinds of household work. Store-purchased white flour and new iron stoves created demands for home-baked cakes, pies, and other fancy goods that had rarely graced the subsistence farmer's table prior to 1820. More and more farm families kept cleaner houses, painted them, and forbade spitting tobacco on parlor floors. | <urn:uuid:78bd70ec-4c2b-460e-a204-ca00227ab693> | CC-MAIN-2013-20 | http://millercenter.org/academic/americanpresident/monroe/essays/biography/8 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.970103 | 831 | 3.890625 | 4 |
ELECTRICAL DIAGRAMS AND SCHEMATICS
Electrical Diagrams and Schematics
Figure 12 Schematic of a Car's Electrical Circuit
When dealing with a large power distribution system, a special type of schematic diagram called
an electrical single line is used to show all or part of the system. This type of diagram depicts
the major power sources, breakers, loads, and protective devices, thereby providing a useful
overall view of the flow of power in a large electrical power distribution system.
On power distribution single lines, even if it is a 3-phase system, each load is commonly
represented by only a simple circle with a description of the load and its power rating (running
power consumption). Unless otherwise stated, the common units are kilowatts (kW). Figure 13
shows a portion of an electrical distribution system at a nuclear power plant. | <urn:uuid:8a726eeb-438b-4120-bcd2-54e07a4ff3f1> | CC-MAIN-2013-20 | http://nuclearpowertraining.tpub.com/h1016v1/css/h1016v1_108.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.833159 | 184 | 3.90625 | 4 |
There are no modern forms, Dicynodonts went
extinct in the Triassic (see Lazarus taxa, below). Dicynodontia
carries no lines to the present day, however, the synapsid line carries
on through the mammalia (Figure 4.1).
Figure 4.1. Diagram showing extinctions and
diversifications of major groups over time. Note the synapsida line
carries on through the mammalia to the present day.
Dicynodont: A Lazarus Taxa?
In 2003, a group claimed to have found a dicynodon fossil attributed to
Late-Cretaceous Australia, approximately 110 million years after the
supposed demise of the dicynodont. This doubles the life history of
these animals and may be a counterpart to the Cerotopsian dinosaurs
during the Cretaceous (Thulborn and Turner, 2003). | <urn:uuid:44c63f78-3e62-4a6b-865b-cdf8ed350f32> | CC-MAIN-2013-20 | http://palaeo.gly.bris.ac.uk/Palaeofiles/Fossilgroups/dicynodontia/modern%20forms.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.855231 | 197 | 3.6875 | 4 |
Australian researchers have found a breakthrough technique that uses eggshells from endangered and extinct birds as a molecular resourcerevealing insights into the behaviour and evolutionary history of Australian feathered fauna.
Murdoch Universitys Dr. James Haile says eggshell has been largely overlooked as a substrate despite its impermeability and resistance to decay, owing largely to the calcium carbonate matrix which acts to protect biomolecules.
Dr. Haile says researchers take the eggs of extinct and endangered birds and grind them down before sequencing the DNA to learn new information about these birds.
For extinct birds such as Madagascars elephant bird, we extract the DNA and compare that to living birds such as emu, cassowary, ostrich and othersfrom that we can see how those birds fit into the broader family tree and at what point they diverged, Dr. Haile says.
For the endangered birds, we take samples of abandoned eggshells and together with DNA samples from chicks and captive birds, develop a population database to get a picture of genetic diversity of the population.
Dr. Haile says the application of his research can help to identify smuggled eggs coming into Australia and learn more about the behavior of Australias endangered birds for conservation strategies.
He says it could even help determine the precise timing of the fragmentation of the supercontinent Gondwana.
For the endangered birds such as Australian megapodes and cockatoos, once you have a data base of genetic information, you can see who is related to who, what is the dispersal of their chicks? How many times a female has mated and if her partner dies will she find another? Dr. Haile says.
Its a way of exploring the private lives of these birds.
For the extinct birds, we know elephant birds were related to emus, cassowaries and others, but we arent sure how closely they were related because bones dont preserve DNA very well due to the heat as well as being very rare.
Elephant bird eggs are the largest ever known, bigger than any dinosaur egg, and very resistant to decay so theyre an ideal but under research source of DNA.
Dr. Haile says future research will improve enrichment techniques to concentrate endogenous DNA from contaminant DNA and will then use that in conjunction with second generation sequencing technologies, which produces up to a million DNA sequences from one sample.
Explore further: Bittersweet: Bait-averse cockroaches shudder at sugar | <urn:uuid:0b205ead-0dd0-458e-bc86-68cabb46357a> | CC-MAIN-2013-20 | http://phys.org/news/2012-01-eggs-reveal-secret-life.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.944963 | 506 | 3.890625 | 4 |
Duane Leavitt, Maine Geological Survey (CREST project)
This activity is designed to engage students in a practical exercise in land use planning; to make the students aware of the positive and negative aspects of land use laws and local zoning ordinances through role-playing. The students represent groups interested in purchasing the same piece of land. Each group must research to devise a plan that is legal and attractive and present proposals to convince the current owners to sell the land to their group. The instructor is advised to use a real plot of land so that real land use laws can be researched.
This description of a site outside SERC has not been vetted by SERC staff and may be incomplete or incorrect. If you
have information we can use to flesh out or correct this record let us know.
Part of the Starting Point collection. The Starting Point collection includes resources addressing the needs of faculty and graduate students designing, developing, and delivering entry-level undergraduate courses in geoscience.
Subject: Environmental Science:Policy:Environmental Decision-Making, Environmental Science:Land Use and Planning Resource Type: Activities:Classroom Activity Grade Level: High School (9-12), Middle (6-8), College Lower (13-14) Environmental Policy: Environmental Decision-Making Earth System Topics: Human Dimensions Topics: /Resources
CMS authors: link to this resource in your page using [resource 22559] | <urn:uuid:767af036-8785-4e0f-9e0c-29638ac12574> | CC-MAIN-2013-20 | http://serc.carleton.edu/resources/22559.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.88547 | 285 | 3.703125 | 4 |
In mathematics, a product is a number or a quantity obtained by multiplying two or more numbers together. For example: 5 × 4 = 20. Here, the number 20 is called the product of 5 and 4. The product of 6 and 4 will be 24, because 6 × 4 = 24.
Capital pi [change]
- (n! means n factorial)
- because we multiply n by itself n times.
- where c is a constant.
From the above equation we can see that any number with an exponent can be represented by a product, though it normally is not desirable.
Unlike summation, the sums of two terms cannot be separated into different sums. That is,
This can be thought of in terms of polynomials: you normally cannot separate terms inside them before they are raised to a power! | <urn:uuid:4373c8a1-bb92-496e-a358-53cf0d4f3dce> | CC-MAIN-2013-20 | http://simple.wikipedia.org/wiki/Product_(mathematics) | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.927594 | 172 | 4.15625 | 4 |
Western Fires Are a Large Public Health Threat Beyond the Region
It’s heartbreaking to watch footage and see photos of the fires rampaging across Colorado and Utah. People are losing their homes, towns are being destroyed, neighborhoods evacuated, firefighters and other emergency responders are stressed to the max.
But one aspect of the blazes has not been widely covered, and that is the public health threat posed by smoke to people many miles away from the fires. The Center for Disease Control reports that smoke from wildfires can hurt your eyes, irritate your respiratory system, and worsen chronic heart and lung diseases. People with heart disease might experience chest pain, shortness of breath and fatigue when they come in contact with smoke while those with pre-existing respiratory conditions such as asthma may experience the inability to breathe normally, wheezing and chest discomfort.
From the CDC website:
Who is at greatest risk from wildfire smoke?
- People who have heart or lung diseases, like congestive heart failure, angina, chronic obstructive pulmonary disease (including emphysema), or asthma, are at higher risk from wildfire smoke. In general, people with these conditions are at higher risk of having health problems than healthy people.
- Older adults are more likely to be affected by smoke. This may be due to their increased risk of heart and lung diseases.
- Children are more likely to be affected by health threats from smoke. Children's airways are still developing and they breathe more air per pound of body weight than adults. In addition, children often spend more time outdoors engaged in activity and play.
The Environmental Protection Agency explains that the biggest threat from smoke comes from fine particles which can cause health problems such as burning eyes, runny nose and illnesses such as bronchitis. Fine particles can also aggravate chronic heart and lung diseases – and even are linked to premature death in people with these conditions.
Though we cannot connect these specific fires and all of the conditions that caused them to climate change, what we’re seeing now foreshadows what we’ll see as climate disruption worsens. | <urn:uuid:dfb80451-5cb2-4f42-b851-646ccf2c38ea> | CC-MAIN-2013-20 | http://switchboard.nrdc.org/blogs/tspencer/western_fires_are_a_large_publ.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+switchboard_all+%28Switchboard%3A+Blogs+from+NRDC%27s+Environmental+Experts%29 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.960446 | 426 | 3.515625 | 4 |
In this experiment you will make your own homemade silly putty also known as a polymer. By varying
the ratio of ingredients and by observing physical properties, you can determine the best recipe for
the putty. So lets get to is and Make Silly Putty
Introduction Make Silly Putty Experiment
You might think that chemists are a bunch of boring scientists who wear lab coats and look at
beakers all day, but did you know that many toys you play with are made using chemistry? Some of
your favorite toys like Gak, Slime and Silly Putty started out as chemistry experiments. In fact, some of
your favorite toys may have been invented by chemists who work for toy companies like: Crayola, Play-
Doh or Mattell.
Chemistry is the study of matter, and how different elements of matter interact. There are many
different kids of matter, which need to be described using the concept of properties. Toys like silly
putty are unique because of they have distinct properties that are different from the properties of other
types of matter. There are two different kinds of properties, chemical properties and physical
Chemical properties are qualities that can be observed during a chemical reaction, like when vinegar
reacts with baking soda. Physical properties are qualities that can be observed during physical
change in the absence of a chemical reaction, like the melting of an ice cube. Physical properties can
be used to describe the state of a chemical, which can be a solid, liquid or a gas. The physical and
chemical properties of Silly Putty are what make it so much fun because it is a polymer that is stretchy
Scientists use properties to describe all of the unique qualities of a chemical or a mixture of
chemicals. To do this they use descriptive language, or words that are used to describe objects.
Some descriptive words used to describe a chemical might be: hot, cold, squishy, hard, soft,
crystalline, granular, smooth, liquid, clear, opaque, runny. There are many different qualities to be
described. You just need to find the right words to use.
The unique physical and chemical properties of a polymer or mixture can be changed by the amount
of each different ingredient used to make them. Sometimes the amount of one ingredient compared
to the amount of another ingredient can make a big difference. This is called a ratio, and a ratio can
be useful to know how much of each ingredient to add to your mixture so you will end up with a
mixture that has desirable properties.
In this experiment you will change the ratio of two basic ingredients in homemade Silly Putty. You will
describe the physical properties of each different mixture using a data table. Then you will choose the
ratio of ingredients to create the best putty product.
Terms, Concepts and Questions to Start Background Research
To do this type of experiment you should know what the following terms mean. Have an adult help you
search the internet, or take you to your local library to find out more!
Elmer's white school glue
Borax (also called 20-Mule Team household cleaner); See "Local Resources for Purchasing
Common Chemicals" on our Guide to Purchasing Chemicals page.
measuring cups and spoons
two recycled glass jars with a lid
Process Make Silly Putty Experiment
- First you will need to prepare solution #1, the 50% glue solution, which is made up of half glue and
- Add one cup of glue and one cup of water to one of the jars.
- Tightly secure the lid to the jar and shake until glue is fully diluted, and no gooey clumps remain.
- Using a permanent marker, label this jar "Solution #1: 50% Glue".
- Next, you will make solution #2, the Borax solution, which is made up of 4% Borax in water. Usually
you would weigh the borax, but you can approximate this solution by adding 2 tsp Borax to 1 cup of
warm water to a jar.
- Tightly secure the lid to the jar and shake until no particles of Borax remain, and the solution is clear.
- Using a permanent marker, label this jar "Solution #2: 4% Borax".
- Now we will add Solution #1 and Solution #2 together in different ratios, to see what properties the
final mixture will have. First we need to make a data table:
-For each mixture, first add the correct amount of Solution #1 (50% Glue) to a Zip-lock baggie.
- Then add the corresponding amount of Solution #2 (4% Borax) to the baggie.
-Seal the baggie, and using your fingers squish the mixture around to mix together the ingredients.
- Write down your observations in your data table.
- When the mixture begins to form a sticky glob, you can take it out of the baggie.
- Write down your description of the physical properties of the material in your table. Remember to
use words like runny, slimy, sticky, hard, soft, bouncy, etc�
- Which ratio of ingredients produced the best product? What will you call your new product?
Now get some friends and try the Make Silly Putty Experiment.
Credits: Sara Agee, Ph.D., Science Buddies
Weird Science Kids
fun cool exciting easy science experiments and
Eduacational Toys for kids | <urn:uuid:e8accb3b-acf3-4d81-a8a2-d3f6cf923c56> | CC-MAIN-2013-20 | http://weirdsciencekids.com/Sillyputty.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.888951 | 1,155 | 3.90625 | 4 |
by James Oberg
First appeared in Air & Space, February/March 1992, pp. 73-79
Reproduced by permission of the author
It was one of the more bizarre proposals offered in response to the funding and design crises surrounding NASA's space station Freedom. In June a shadowy organization calling itself the "Center for Strategic Space Studies" suggested that instead of building Freedom, NASA should take the back-up Skylab on display in the National Air and Space Museum in Washington and launch that.
The disgruntled NASA employees who suggested this idea did it anonymously, perhaps feeling that the space agency has come to enforce unanimity of thought not by encouraging superior ideas but by imposing bureaucratic discipline. And while many were quick to dismiss the proposal as impractical, it did briefly succeed in stirring debate throughout the space community. After all, with Skylab the United States once had a successful manned space station. Yet NASA let it slip through its fingers and fall to Earth in 1979.
In the late 1970s NASA had considered saving Skylab by sending an early space shuttle mission to boost it into a higher, more stable orbit, where astronauts could have studied how it had been affected by its years in space. Even more ambitious studies concluded that Skylab could have been repaired, reopened, and expanded. Had that happened, the history of the US space program might have been very different.
NASA could have begun the shuttle program with an embryonic space platform, a destination to shuttle to. Experiments still in the planning stages in the 1990s might have been carried out in the 1980s, and NASA could have accumulated the experience necessary to advocate, design, and construct a permanent space station.
"It was a very serviceable, useful facility," recalls Jack Lousma, an astronaut who lived aboard it for two months and was later assigned to a shuttle flight that was supposed to rescue it. "It would have made a good follow-on set of missions, a nucleus for expansion."
That would have been a grand role for a spacecraft that started out as a modified propellant tank from a Saturn rocket's upper stage. Refitted as the Orbital Workshop, or OWS, the large tank was given two solar panels and a pair of small modules (an airlock module and a multiple docking adapter) at one end and a solar telescope assembly that swung out to one side. During 1973 and '74, a trio of three-man crews studied the sun and Earth from the space station on missions lasting 28, then 59, and finally 84 days.
For a time, though, Skylab's fate was in doubt. During the launch a meteoroid shield tore off, taking one of the solar panels with it. Then the other panel jammed, and the first crew had to make an emergency spacewalk to deploy it and save the station. The lost meteoroid shield was supposed to double as a sunshade, so the astronauts also had to rig up a replacement shade to bring the workshop's internal temperatures down to tolerable levels. It was an inauspicious beginning, but Alan Bean, who commanded the second mission, recalls, "It got better with time. More things were working at the end of the mission than at the start."
The station, never designed to be resupplied, was retired after the third mission ended on February 8, 1974. On the remote chance somebody else would venture aboard, the departing astronauts left a bag of food, clothing, film, and camera filters near the front hatch, tied securely to the telescope control panel. As they left the station, they removed the inside locking pin from the airlock hatch -- in effect, putting out the welcome mat.
In the end, it was the sun that spelled doom for Skylab. The final crew used their Apollo spacecraft to nudge Skylab high enough to keep the station in orbit until sometime in 1983. But in the late 1970s solar activity intensified, heating and expanding the upper atmosphere enough to increase the drag on the space station. As Skylab's orbit decayed and its life expectancy decreased, the shuttle program encountered more and more delays. Early plans had called for the reboost mission to be undertaken on the sixth shuttle launch, but schedule pressures pushed it as far ahead as the second mission. However, STS-2 wasn't launched until November 12, 1981, more than two years after Skylab's charred remains had dropped across western Australia when the spacecraft fell on July 11, 1979.
Many at NASA were glad to see the end of Skylab. "It could well have been a snare and a delusion," says Joe Loftus, Johnson Space Center's advanced planning director. "It might have confused us, diverted us." That is, he elaborated, the energy expended on the rescue and repair mission might ultimately have been wasted, deflecting attention from more profitable investments in more promising projects.
Alan Bean disagrees: "I think we should have kept it up there. It wouldn't have detracted from anything. Maybe it would have had the opposite effect; we could have really demonstrated space station operations."
When plans to launch a second Skylab were scuttled in 1975, some preliminary thought was given to reopening the first one. With shuttle orbital missions due to start in 1979 and Skylab's orbit thought to be stable at least through the early 1980s, John Yardley, NASA's associate administrator for manned spaceflight, initiated a study to demonstrate what the shuttle could do on a Skylab visit. At the very least, the crew could attach a rocket stage to the station to ensure that when it did return to Earth, it would come down in an ocean.
Over the next year NASA worked to determine the likely condition of the ageing spacecraft. Engineers at the Skylab project office in Huntsville, Alabama, and Skylab contractors such as Martin Marietta were convinced the station would be in surprisingly good shape. More than just a handy target for a shuttle mission, Skylab was potentially a resource of great value.
Granted, the long exposure to space would have taken its toll. The hatch seals would have become brittle, gas pressure would have slipped (particularly within high-voltage components protected by high-pressure gas insulation), contamination would have built up on windows, mirrors, and filters, and mechanical parts would need lubrication. In addition, cosmic radiation and extreme temperature cycling would have degraded electronics and electrical parts.
But the wear and tear was in fact one of Skylab's most attractive traits. The information about effects of long-term space exposure would be vital to the design and construction of a new, permanent space station.
The engineers also catalogued the Skylab systems expected to be operable. These included refrigeration, oxygen/nitrogen distribution, carbon dioxide control (which used a molecular sieve more advanced than anything that has flown since), waste management, medical monitoring, trash disposal, ventilation, and the hatches (spare seals were aboard).The thermal control system would require servicing with cooling fluid. The power, communications, and data management systems would need augmentation. "All other systems should require minor flight activities for reactivation," concluded the final report to NASA headquarters.
Of the 6,000 pounds of water launched in 1973, nearly 2,000 pounds remained (about 180 man-days' worth). "Probably potable, but may taste bad," the engineers concluded. No live organisms were expected, but the water "may be off color." Taste and' color problems might make it useful only for washing (or, later, for electrolysis into breathing oxygen). The water system had valves within the workshop for eventual refilling.
There was an estimated 1,700 pounds (420 man-days) of oxygen in the tanks. Since the refill valves were near the airlock, it would be fairly easy for astronauts to replenish the oxygen during a shuttle visit.
The station's atmosphere did present one basic engineering problem for shuttle missions: Skylab's atmosphere was pressurized at 5 pounds per square inch, but the shuttle's was three times that, equal to sea level on Earth. An astronaut moving from the shuttle to Skylab would have to undergo three hours of pre-breathing in a transfer chamber to adjust to the change. Skylab's workshop could later be raised to 15 psi with no safety problems, but the airlock module and its extravehicular activity hatch could tolerate only 8 or 9 psi. Either these small modules would have to be replaced (or lined with a flexible airtight inner layer) or shuttle pressure could be temporarily reduced, as it is today prior to EVA.
And off-the-shelf shuttle equipment would need extensive modification to be installed in the old station. Merely getting it aboard would have been a problem: Skylab's hatch was only 30 inches in diameter-- half the size of the shuttle's.
Although only a third of Skylab's trash tank had been filled, the latches on the trash airlock had jammed. Alternate systems would probably be needed. But microbiologists were excited at the prospect of studying microbes that had been reproducing in the trash for hundreds of generations in a spacecraft. They also expected to find interesting fungal spores on the walls and in the air (something not expected to excite visiting astronauts).
Skylab's communications system was operable but already obsolete. The shuttle would use higher frequencies than Apollo missions, and already the old ground sites were being phased out. New monitoring sensors would eventually have to be set up in the station and shuttle-compatible radios installed.
Although the solar cells were ageing and good for only a few kilowatts of electrical output, the power buses and batteries were in good shape for reactivation. More power would be needed, however.
Probably the most serious problem in reactivating Skylab would have been the state of the station's attitude control system. One of three momentum wheels necessary to keep the station stable had already failed, and the nitrogen supplies in the thruster system were low. They could be replenished, but that would require an astronaut with a manned maneuvering unit to get to the feed valves. The star tracker (a vital component for attitude control): had also failed.
On the plus side, Skylab rescuers would get their shuttle repair missions "free," since the rescue was considered a good exercise for testing the new spaceship's capabilities. And the needed power and attitude control could be provided by an unmanned vehicle already in development, the Power Extension Package. The PEP was designed to be a space powerhouse, waiting in Earth orbit for those visits when the shuttle needed more electricity for missions with the portable laboratory it sometimes carries called Spacelab. Attracted by the hefty 25 kilowatts generated by the PEP's solar panels, the Skylab rescuers suggested attaching the PEP to the station and using its power, while the PEP's attitude control sensors and thrusters kept the station lined up properly.
In late 1977 NASA headquarters completed a four-phase rescue plan. During the first phase, shuttle astronauts would boost Skylab to a higher orbit to give it an additional five years of life. Various shuttle-based boosting techniques were proposed, including pushing (the off-balance Skylab structure would have been a huge dynamic challenge) and towing (on a cable). Martin Marietta started developing the Tele-operated Reboost System, a cluster of rocket engines that could be attached to Skylab.
Astronauts Fred Haise and Jack Lousma were assigned to the mission and began training to use the TRS.
Once Skylab was high and stable, phase 2 would commence. Engineers would develop refurbishment kits with the necessary tools and parts, and shuttles would make two visits, during which astronauts would enter the station. On the first visit, scheduled for January 1982, they would attach a modified version of the docking adapter built for the Apollo-Soyuz mission. Then they would test the thermal control system, install valves for repressurization, and reactivate all power buses. During the second visit, in August 1983, astronauts would install thermal and electrical units, service the thermal system, and conduct more extensive inspections and checkouts to assess the effects of exposure on solar cells, insulation, windows, seals, paints, film, lubricants, and other materials.
In March 1984 the shuttle crews for phase 3 would attach the PEP to Skylab, refurbish the station's scientific equipment, and operate the station in both tended (30 to 90 days) and unattended modes. They could use the Apollo Telescope Mount (all it required was more film) and the earth resources experiments. Other simple experiments could be taken up and installed as well.
When operations intensified, a large docking/interface module would be attached to the front end of Skylab, with ports for the PEP, the shuttle, and an additional logistics module launched full of supplies. Additional ports would also be available for Spacelab modules. The old Skylab would begin to expand, piece by piece.
Phase 4 would be a five-year plan of growth, with the addition of Spacelab modules and pallets and perhaps a construction platform based upon the shuttle's external tank. There was talk of eventually giving Skylab a larger power module (150 kilowatts) or a large dish antenna (or both) for radio astronomy or power transmission tests.
Once modified to accommodate six to eight astronauts, Skylab could serve as a space depot, experiment hangar, general-purpose laboratory, and habitat for construction crews working on more advanced structures. Equipment for the first three phases was estimated to cost about $60 million, not including launch costs or the power module, which were funded from different budgets.
But NASA, fixated on the shuttle program, wasn't really interested. Neither were those who controlled the purse strings in Washington. "I'd met with House and Senate staffers," recalls Joe Loftus. "In the end it was admitted that there was an argument to preserve Skylab, but it lost out to the fact of the high cost on immediate assets."
Besides, everything in the plan depended on getting Skylab boosted to a safe orbit, and that looked less and less likely as time passed. "It was nothing dramatic." recalls John Rivers, a NASA engineer who worked on the project. "But month by month the overlap between Skylab dying and the shuttle being born just dwindled into negative numbers."
As it became clear that a shuttle boost wasn't going to happen, alternate methods were considered, including expendable rockets. "We offered to fly (the TRS on a Titan III," says Robert J. Molloy, the project's director at Martin Marietta. "That was seen as a bit self-serving, since Martin Marietta manufactured the Titan." It also would have taken two launches to get the entire booster into orbit. An Air Force Atlas Agena also might have done the job. Some even considered going to the Soviets for help, but their manned Soyuz clearly didn't have enough power. (An unmanned space tug named Cosmos- 929 did, but its existence was a secret at the time.)
The main drawback to all the schemes, however, was money. All of them would have diverted funds that were needed for the shuttle. "It was certainly feasible," says Robert Allen, one of the Skylab's manager's, about the rescue plans. "We were making some pretty good studies. It just cost more than we had ever considered."
The proposal finally died. There had been no obvious oversights, just a creeping conspiracy of circumstances that left a problem with no real solution. Besides, NASA hall great hopes for a future beyond Skylab, one that included more advanced stations constructed from three or four space shuttle loads deployed in the 1980s. For some, Skylab's continued existence threatened those plans. 'There was considerable resistance within NASA," says Martin Marietta's Molloy.' "The enthusiasts were those who had worked on Skylab and were quite proud of it, but it interfered with the more global vision of glory shared by the later generation at NASA." Given a risky cheap way and an expensive fancy way, NASA (not for the first or last time) opted for spending a lot of money in the future rather than a little money immediately.
But could Skylab really have been revived? Most likely, yes. When it was turned on briefly by ground command in 1978, the station's power, command and control, and attitude systems all functioned adequately. Years later, when the Soviet Salyut 7 station died and froze, it was revived from conditions far more extreme--and then operated normally. NASA's Long Duration Exposure Facility satellite, retrieved in 1990 after almost a decade in orbit, showed wear and tear but no serious damage.
Would it have been worth the effort? Visits and brief experiments were possible, but the grandiose plans for converting the old station into a space city by small steps would have encountered serious problems. "Whether it was something to build upon was doubtful," says Robert Allen. "Skylab was '60s technology and I seriously doubt that anyone would have wanted to build onto that."
Originally, plans for long-term shuttle visits required the shuttle to shut off its fuel cells and use energy from the station. Later NASA decided that the shuttle would have to keep its fuel cells on line--there was too much danger that once shut off, a fuel cell might not restart properly in space. The long manned missions to Skylab originally envisioned probably wouldn't have been possible.
Perhaps the most damning argument against Skylab was something any real estate agent can appreciate: location. The high-inclination orbit (tilted 50 degrees from the plane of the equator) was not convenient for shuttle missions. To reach Skylab, a shuttle would have to be launched more to the north than usual, sacrificing some of the boost offered by Earth's eastward spin. That wasn't a major penalty for expendable spacecraft and boosters (about 10 percent of maximum payload weight), but because the shuttle carries its heavy wings and engines back to Earth, the weight sacrifices would have to come from the payload. (To avoid this unacceptable loss, Freedom is to be built in an easterly orbit from Florida, with an inclination of 28 degrees.) (NOTE ADDED IN 1999: Now isn't this ironic, that in the end we chose to build the International Space Station at an even higher inclination, 52 degrees, in order to make it accessible to the Russians, and we wound up paying the performance penalty anyway).
But even with its drawbacks, a revived Skylab would have been a tremendous temptation to mission planners. Each incremental improvement--and all the expensive refurbishment and maintenance that would have become necessary year by year--would have seemed only a little bit more to spend. NASA would have been in the position of a poker player unwilling to walk away from the money he had in the pot even as the stakes went higher and higher. Would NASA ever have abandoned a revived Skylab to develop a newer design in a convenient orbit? Bureaucratic inertia might have made that unlikely.
Today the "what ifs" still tease, but the history is already written. Yes, operating a revived and refurbished Skylab would have provided valuable experience in space operations. It would have been better than nothing, which is what NASA has today--ironically, because the very sacrifice of Skylab was thought to be necessary to ensure future programs. One thing Skylab taught is that we should glance back from time to time to avoid old mistakes and gain inspiration from old successes. But to move forward into the future, we don't need to revive the past. | <urn:uuid:ede3ac7a-080b-4e20-a079-7c747fb1db3e> | CC-MAIN-2013-20 | http://www.astronautix.com/articles/skyyfate.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.97637 | 4,018 | 3.640625 | 4 |
The difference is a function of one of nanotechnology's principle phenomena: the traits of a bulk material are different than structures of the same material on the nanoscale.
"When you're working at bigger sizes, the surface is not as important. The surface to volume ratio the number of atoms on the surface divided by the number of atoms in the whole material is a very small number," Agarwal said. "But when you make a very small structure, say 100 nanometers, this number is dramatically increased. Then what is happening on the surface critically determines the device's properties."
Other researchers have tried to make polariton cavities on this small a scale, but the chemical etching method used to fabricate the devices damages the semiconductor surface. The defects on the surface trap the excitons and render them useless.
"Our cadmium sulfide nanowires are self-assembled; we don't etch them. But the surface quality was still a limiting factor, so we developed techniques of surface passivation. We grew a silicon oxide shell on the surface of the wires and greatly improved their optical properties," Agarwal said.
The oxide shell fills the electrical gaps in the nanowire surface, preventing the excitons from getting trapped.
"We also developed tools and techniques for measuring this light-matter coupling strength," Piccione said. "We've quantified the light-matter coupling strength, so we can show that it's enhanced in the smaller structures,"
Being able to quantify this increased coupling strength opens the door for designing nanophotonic circuit elements and devices.
"The stronger you can make light-matter coupling, the better you can make photonic switches," Agarwal said. "Electrical transistors work because
|Contact: Evan Lerner|
University of Pennsylvania | <urn:uuid:341e8709-6383-4afc-b8ce-6344e74e0829> | CC-MAIN-2013-20 | http://www.bio-medicine.org/biology-technology-1/penn-researchers-break-light-matter-coupling-strength-limit-in-nanoscale-semiconductors-19735-2/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.917051 | 373 | 3.953125 | 4 |
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physics of sound production
In stretched strings
any musical instrument that produces sound by the vibration of stretched strings, which may be made of vegetable fibre, metal, animal gut, silk, or artificial materials such as plastic or nylon. In nearly all stringed instruments the sound of the vibrating string is amplified by the use of a resonating chamber or soundboard. The string may be struck, plucked, rubbed (bowed), or, occasionally,...
use in lute
Most lute strings have traditionally been made of animal intestines (gut), metal, or silk, though nylon has become a common replacement for gut. Whatever the material, each string must be of equal thickness throughout its length. Some lutes have only a single string, but the great majority have three, four, or more. Very often there are sets, or courses, of two strings to a pitch, so that an...
What made you want to look up "strings"? Please share what surprised you most... | <urn:uuid:3d2756f0-580d-4fa8-a29b-eb99da33183d> | CC-MAIN-2013-20 | http://www.britannica.com/EBchecked/topic/569222/strings | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.910741 | 239 | 3.78125 | 4 |
British Museum collections, £12.99
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Vandals and the Roman Empire
The Vandals formed a group of Eastern Germanic peoples, originally perhaps from Jutland. They occupied lands between the Oder and Vistula rivers in the first century AD. According to a Roman historian, they lived in waggons and moved from pasture to pasture tending their herds of cattle and horses. While living in the Danube region the Vandals supplied troops for the Roman army and adopted the heretical Arian form of Christianity. Later, when they migrated to areas of the Roman Empire, Arianism set the Vandals apart from native populations.
At the end of 406 the Vandals joined with escaped slaves from Pannonia and other barbarian tribes, including the Suevi, the nomadic Alans, and some Goths, and crossed the frozen Rhine near Mainz into Roman Gaul, probably to escape from domination by the Huns. After ravaging France they crossed the Pyrenees in 409 and eventually settled in southern Spain for a while. They occupied the countryside, but left the towns to the native population. Their name might be preserved in that of Andalusia, but this is uncertain. The Vandals seized Roman ships and made piratical raids around the Mediterranean, even as far as the coasts of Greece.
Allegedly at the invitation of a disgraced Roman governor, Count Boniface, the Vandals crossed to North Africa in 429. A census, taken at that time, numbered 80,000 males amongst them. Under King Gaiseric they went on to establish an autocratic kingdom in what is today eastern Algeria and Tunisia. The kingdom centred on Carthage, the wealthy third city of the empire and Rome's main source of grain. There they built a fleet with which they were able to seize the Balearic Islands, Sardinia, Corsica and western Sicily. They even captured Rome itself briefly in 455, stripping the city of its riches and carrying off the empress Eudoxia and her two daughters. The emperor was forced to recognize Vandal rule after an attempt to recover Africa was defeated in 460 and the Vandal kings issued their own coins as a symbol of their independence. | <urn:uuid:bbee04c1-770a-4f39-81f8-d0c228091de2> | CC-MAIN-2013-20 | http://www.britishmuseum.org/explore/highlights/articles/v/vandals_and_the_roman_empire.aspx | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.97157 | 456 | 3.828125 | 4 |
In Fig. 30-50, a metal rod is forced to move with constant velocity along two parallel metal rails, connected with a strip of metal at one end. A magnetic field of magnitude B = 0.414 T points out of the page. (a) If the rails are separated by 19.9 cm and the speed of the rod is 50.0 cm/s, what is the magnitude of the emf generated in volts? (b) If the rod has a resistance of 20.0 Ω and the rails and connector have negligible resistance, what is the current in amperes in the rod? (c) At what rate is energy being transferred to thermal energy? | <urn:uuid:a532a607-c667-40e6-a21c-fdf1f13263e5> | CC-MAIN-2013-20 | http://www.chegg.com/homework-help/questions-and-answers/fig-30-50-metal-rod-forced-constant-velocity-parallel-metal-rails-connected-strip-metal-en-q1250864 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.931056 | 139 | 3.671875 | 4 |
This brief explanation describes the methods used in the simulation above to determine the Right Ascension (RA) and Declination (Dec) of the Sun, Mercury, Venus, Mars, Jupiter, and Saturn. It assumes some background in astronomy. However, there is a reasonably verbose glossary linked to what may be unfamiliar terms. In truth, this explanation is more for those wishing to know exactly what assumptions underlie the above simulation. However, this explanation does serve as a good case study in how to determine the planets' positions.
The simulation overlays the RA and Dec of the five planets visible to the naked eye and the sun atop an cylindrical projection of the Earth's sky. The name planet roughly translates to "wanderer." Knowing the geocentric model held for so long, many of my students simply assume the planets move about the sky in much the same manner as the moon or sun--steadily creeping eastward. They do not, and I developed this simulation to illustrate their true wandering nature.
Solving Kepler's Equation & Calculating Ephemerides
When first approaching this problem, I knew that I would need to solve Kepler's Equation and have a little fun with reference frames. I was surprised by the explanations available on the web. Most of them fell short of what I was looking for. They were either strictly qualitative or, if quantitative, unnecessarily opaque. This resulted mostly from having too few or poorly executed diagrams and illustrations. There were a few notable exceptions, and I have cited them in the references section. As I never formally studied celestial mechanics, these sources were my teachers and greatly helped acquaint me with the problem and its solutions. What I've attempted to do here is to weave together a relatively cogent "How to" on the solving of Kepler's Equation and the calculation of planetary positions in the Earth's sky.
Johannes Kepler (1571-1630) was a mathematician, astronomer, and Copernican. He believed that the Sun, not the Earth, lay at the center of the universe. He refined Copernicus's view of a heliocentric (Sun-centered) universe, making it into more than simply a competing theory for the geocentric (Earth-centered) model. Under Kepler it would become the superior predictive model. In his work Kepler formulated three laws of planetary motion first set down together in Harmonice Mundi (Harmonies of the World), 1618, and here they are.
2. An imaginary line connecting the sun and a planet sweeps out equal areas in equal times as the planet moves through its orbit. A consequence of this is that a planet moves fastest when closest to the Sun. Newton will have something to say about this.
3. The square of the period of a planet's orbit is proportional to its distance from the Sun cubed. When the units used for distance are Astronomical Units (AU) and time is measured in years, this relationship can be written explicitly as an equation relating the planet's period P and the semi-major axis of its orbit a (eq.1).
Kepler's Laws meant that given only a handful of orbital parameters, one could say where a planet had been and would be. To state this explicitly, astronomers make use of Kepler's Equation (eq.2).
Kepler's equation is a transcendental equation. This means there is no general solution. So to find the location of a planet at a time t, we must solve for that time using some numerical method. First let us work with what we have. NOTE: You may find it helpful to reference Figure 2 (pop-up) to help visualize some of the variables referenced here.
Only e is time independent. So we consult our orbital parameters for its value and then solve for the mean anomaly (eq.3), M in Kepler's Equation (eq.2). The mean anomaly is just the angle with the perihelion that the planet would have if the orbit was an ellipse with eccentricity = 0, i.e., a circle. We call the imaginary planet moving along such an orbit the mean planet. In such a case the planet would move with a velocity V = (2*PI)/Period .
As you can see, the mean anomaly is just the mean planet's velocity times the time elapsed since it was last at the perihelion.
We can now find the eccentric anomaly using some numerical method. This simulation makes use of successive approximation. Once we have a value for E with which we are happy, we can find the true anomaly (eq.4). The true anomaly is the ACTUAL angle between the perihelion and the planet.
From here it is a simple matter to find the planet's radial distance (eq.5) from the sun.
We now have the planet's polar coordinates (r, v) within the plane of its orbit such that the X axis points from the Sun towards the Perihelion, point P.
Now we find the Heliocentric Ecliptic coordinates (x, y, z) for the planet by converting from polar to cartesian coordinates and rotating the frame such that the X axis points towards the first point of Aries.
We then rotate the coordinates into Heliocentric Equatorial coordinates (X, Y, Z), making use the matrix below.
However, our display shows the positions of the planets from the Earth. So we need to switch our vantage point to that of a geocentric system. To do this we first repeat the above process, solving for the Earth's Heliocentric Equatorial coordinates. We want to know the Sun's Geocentric coordinates. So here we will approximate this as the inverse of Earth's heliocentric coordinates. This is the same method used to find the Sun's location for display. It is important to note, however, that this is just an approximation, as what we really find is not the location of the Earth but rather that of the Earth-Moon system's barycenter. This simplification is responsible for limiting the simulation's accuracy. Note: This is not an issue for the Build Your Own Solar System simulation for teachers as the hypothetical "Earth" has no moon in that simulation. We then add the Sun's geocentric coordinates to those of the heliocentric coordinates of our planet. This shifts the coordinates, giving us the Geocentric equatorial coordinates (xp, yp, zp) for the planet.
Having the planet's Geocentric coordinates, it is a simple matter to convert them into Right Ascension and Declination. Note: Watch you signs here; if you're not careful, it WILL get messy.
That's it. We can now solve for many discreet times and collect the data into tables to construct ephemerides. If you are interested in finding more accurate calculations for the planets' positions, consider buying a copy of the Astronomical Almanac from the US Naval Observatory or making use of JPL's Horizons system.
References & Further Reading:
1. To anyone interested in why it is the orbits of the planets are elliptical, I suggest finding a copy of D. & J. Goodstein's Feynman's Lost Lecture: The Motion of Planets Around the Sun. W. W. Norton & Company. New York, NY. 1996.
2. A copy of Kepler's Harmonice Mundi (Harmonies of the World) as well as many other ground breaking texts in astronomy have been compiled into one tome: Stephen Hawking's On The Shoulders of Giants: The Great Works of Physics and Astronomy.
3. For what I found to be the most rigorous on-line handling of this material, try Dr. J. B. Tatum's Celestial Mechanics: http://orca.phys.uvic.ca/~tatum/celmechs.html (Link current as of April 2004).
4. The orbital parameters used here came from the JPL Solar System Dynamics Group's "Planetary Orbital Elements," JPL Solar System Dynamics: http://ssd.jpl.nasa.gov/elem_planets.html. (Link current as of April 2004).
Ascending node: The point of intersection between a planet's orbit and the plane of the Sun's equator, where the planet is moving northward ("upward") across the plane of the Sun's equator.
Celestial sphere: A gigantic imaginary sphere surrounding a stationary Earth upon which the stars are affixed. It was once believed that the celestial sphere was real. However, it is now regarded solely as a convenient descriptive tool.
Descending node: The point of intersection between a planet's orbit and the plane of the Sun's equator, where the planet is moving southward ("downward") across the plane of the Sun's equator.
Eccentricity: A measure of how "elliptical" an eclipse is (measured from 0 to 1). For example, a circle has an eccentricity of zero, not very elliptical. A relationship can be stated mathematically between the semi-major axis a, the semi-minor axis b and the eccentricity e where:
Above are four ellipses with varying eccentricities. The first is a circle.
Ellipse: One of the conic sections, those shapes which are the intersection of a cone and plane. The ellipse is a geometric shape that looks like a squashed circle. You can easily make an ellipse with two thumb tacks and a loop of string. Place the two tacks into a paper and loop the string around them. Place a pencil in the loop of string and move it outwards until the loop becomes taut. Move the pencil around the tacks always keeping the slack out of the loop. The figure drawn is an ellipse. The points where the thumbtacks lie are the foci of the ellipse (singular focus).
Orbital parameters: A set of physical parameters for the orbit of a planet sufficient to predict the position of the planet at a given time t. The orbital parameters used in the simulation above can be found at: http://ssd.jpl.nasa.gov/elem_planets.html (valid as of June 2004).
Retrograde Motion: The westward motion of the planets against the background stars. In order to maintain the Earth's central location and a commitment to perfect circular motion, geocentrists devised a set of epicycles (orbits within orbits) upon which the planets would rotate. The motion of the planet about its epicycle allowed for the presence of retrograde motion. However, heliocentrists' Sun-centered model had no need for epicycles as retrograde motion could bee seen as one planet simply overtaking another as they raced about the Sun. See Animation.
Successive approximation: A numerical method by which a solution is found to an equation by substituting in guesses for the answer on both sides of the equation. The sides are evaluated and the first guess that produces a difference between the sides of less than a pre-defined tolerance is taken to be the answer.
Vector: A quantity consisting of both direction and magnitude (e.g., velocity).
A free tool for creating and observing your own solar system, designed for astronomy teachers & students.
A dynamic illustration (animation) of retrograde motion, portraying the geocentric and heliocentric models.
A dynamic illustration (animation) of a planet's synodic & sidereal period.
An app that helps solve common introductory mechanics problems, consider it training wheels for learning mechanics.
Answers to science questions, brief lessons, and ideas for teachers and students.
An on-line tool and database for running quiz bowl practice rounds in accordance with National Science Bowl rules.
Phylm, pronounced "film," is a portmanteau combining physics and film and the umbrella name given to a number of physics/film projects I've worked on, including an annual Phylm Prize, and a curricular unit for physics teachers.
My first byline, Moving Targets is a Hot Science piece I wrote while interning for NOVA Online, the companion site to PBS's NOVA. It explains how to measure the radial velocities of stars. | <urn:uuid:f788ac53-91e4-494d-9ae7-9281e9dbbdb0> | CC-MAIN-2013-20 | http://www.davidcolarusso.com/astro/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.925138 | 2,552 | 3.515625 | 4 |
In this article, Martin Bond discusses XML and its associated APIs and standards, and how XML can be used to create flexible structured data that is inherently portable. This excerpt is from chapter (Day) 16 of Teach Yourself J2EE in 21 Days, second edition, by Martin Bond, et. al. (Sams, ISBN: 0672325586)
The outermost element in an XML document is called the root element. Each XML document must have one and only one root element, often called the top level element. If there is more than one root element, an error will be generated.
The root element can be preceded by a prolog that contains XML declarations. Comments can be inserted at any point in an XML document. The prolog is optional, but it is good practice to include a prolog with all XML documents giving the XML version being used (all full XML listings in this chapter will include a prolog). A minimal XML document must contain at least one element.
There are two types of XML declaration. XML documents may, and should, begin with an XML declaration, which specifies the version of XML being used. The following is an example of an XML declaration:
<?xml version ="1.0"?>
The XML version element tells the parser that this document conforms to the XML version 1.0 (W3C recommendation 10-February-1998). As with all declarations, the XML declaration, if present, should always be placed in the prolog.
The other type of declaration is called an XML document type declaration and is used to validate the XML. This will be discussed in more detail in the section titled "Creating Valid XML" later in this chapter.
An element must have a start tag and an end tag enclosed in < and > characters. The end tag is the same as the start tag except that it is preceded with a / character. The tags are case sensitive, and the names used for the start and end tags must be exactly the same, for example the tags <Start>...</start> do not make up an element, whereas <Start>...</Start> do (both tags are letter case consistent).
An element name can only contain letters, digits, underscores _, colons :, periods ., and hyphens -. An element name must begin with a letter or underscore.
An element may also optionally have attributes and a body. All the elements in Listing 16.2 are well-formed XML elements. All attributes must be quoted, both single and double quotes are permitted.
Listing 16.2 Valid XML Elements
<start>this is the beginning</start>
<date day="16th" Month="February">My Birthday</date>
<today yesterday="15th" Month="February"></today>
Table 16.1 describes each of these elements.
Table 16.1 XML Elements
XML Element Includes
A start tag, body, and end tag
<tag attribute="text"> text </tag>
An attribute and a body
<tag attribute="text"> </tag>
An attribute but no body
Short form of attribute but no body
A start tag and end tag but no body
Shorthand for the previous tag
Although the body of an element may contain nearly all the printable Unicode characters, certain characters are not allowed in certain places. To avoid confusion (to human readers as well as parsers) the characters in Table 16.2 should not be used in tag or attribute values. If these characters are required in the body of an element, the appropriate symbolic string in Table 16.2 can be used to represent them.
Table 16.2 Special XML Characters
Open angle bracket
Close angle bracket
The elements in an XML document have a tree-like hierarchy, with elements containing other elements and data. Elements must nest—that is, an end tag must close the textually preceding start tag. This means that
<b><i>bold and italic</i></b>
is correct, while
<b><i>bold and italic</b></i>
This chapter is from Teach Yourself J2EE in 21 Days, second edition, by Martin Bond et. al. (Sams, 2004, ISBN: 0-672-32558-6). Check it out at your favorite bookstore today. Buy this book now. | <urn:uuid:a25bd9ad-8d26-4a2b-ba05-59bb05d07879> | CC-MAIN-2013-20 | http://www.devshed.com/c/a/Java/Integrating-XML-with-J2EE/3/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.804169 | 899 | 4.28125 | 4 |
Shift a Cosecant Function on a Graph
The cosecant function is affected by the same multiplication, addition, and subtraction principles that affect the other functions. For example, adding or subtracting a number to or from the cosecant function results in the graph going up or down. Adding or subtracting numbers to the angle variable slides the graph left or right.
The preceding figure shows two slides: moving the graph to the left by 2 units and up by 2 units. The equation of that graph is y = csc (x + 2) + 2.
Although the asymptotes are left out, you can still tell where they are — the shape of the graph is pretty clear.
Multiplying by a number changes the steepness and period of the cosecant function. If you multiply the function by 2, the curve gets steeper and has more space between its bottom and top. If you multiply the angle variable by 2, twice as much of the curve fits in the usual amount of horizontal space. The second figure shows both changes in the graph of y = 2csc 2x. | <urn:uuid:43137a3c-3514-4a08-84a2-a60c4243b7f0> | CC-MAIN-2013-20 | http://www.dummies.com/how-to/content/shift-a-cosecant-function-on-a-graph.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.925687 | 234 | 4.1875 | 4 |
|junior high school first year||To consolidate the grammar 'Whose' and 'It's', and to reinforce the distinction between her/his.||whose, his, hers, mine...||15 mins||a big, opaque bag or box|
Instruct the students, or have the JTE instruct them, to close their eyes and put their heads onto their desks; most of them will be so happy to oblige that you may have trouble getting them erect again later. While your class is 'sleeping', walk around the room appropriating various objects from random sleepers. Snatch things like pens, pen cases, shoes, hair clips (good for a few muffled squeals from the girls which adds interest) erasers, bags, etc., but try to limit yourself to articles which the students know by name, and aren't too personal. After 'liberating' about 10 objects, wake your students and briefly practice the question and answer forms before selecting one of the objects and asking, "Whose is this?" Add some extra interest and humour to the activity at this point by climbing partway into the bag/box in search of an item. Such occasional deviations from the norm help to focus the students' attention.
The first student to raise their hand/stand up can answer, "That's my " or "It's her/his " while pointing at the owner. A correct answer ought to receive a reward of some kind; I use lottery tickets, others have a point tally system with a reward for reaching a nominated goal, others use candy, which is very popular with the students, but which raises some interesting psychological problems. After returning 2 or 3 items, have the identifier come to the front to select the next item, and to ask the question "Whose ..?". At this point the JTE and ALT can take a well earned break and stand back and let the students perform the activity by themselves.
View this page without frames (good for editing or printing)
Complete index ... without frames | <urn:uuid:d4ec87fd-ebe6-4c9c-94ca-ec42b49a32af> | CC-MAIN-2013-20 | http://www.edochan.com/teaching/thief.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.940582 | 414 | 3.53125 | 4 |
Building a Wind Gauge
Measure how strong the wind blows.
Here is a simple wind gauge for use in breezes. It will indicate direction and relative speeds. Use the wind gauge to find out where the wind blows strongest. Compare gauge readings. Do obstacles affect wind speeds and direction?
Left side toward direction wind is blowing from. Bottom parallel to ground.
- Print out the pattern using your Internet browser software.
- Trace the pattern onto cardboard.
- Cut out the light cardboard wind gauge.
- Tie thread or string in hole.
- Move gauge until thread is blowing the same way edge furthest from the string is pointing. This indicates wind direction. Keep pointing the gauge in that direction.
- Where the thread points along arc indicates a relative velocity. Make marks with a pen along the arc to show how hard the wind is blowing.
Reprinted with the permission of the California Energy Commission. © 1994-2008 California Energy Commission.
Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety. | <urn:uuid:d3d2efc8-3810-46b5-8fc9-49a59df1f551> | CC-MAIN-2013-20 | http://www.education.com/science-fair/article/building-wind-gauge/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.874086 | 275 | 3.859375 | 4 |
After the collapse of the Old Kingdom at the end of the 6th Dynasty, there was first a short interregnum (a period of 70 days, misunderstood by later editors of Manetho's 'Aegyptiaca' and turned into the 7th Dynasty). There then followed a long-drawn out fight for the throne (8th Dynasty), during which time no less than 17 kings ruled in less than 20 years, according to the Abydos king list, among others. The kings of Herakleopolis near the Faiyum eventually seized power, although not over all of Egypt. They are called the 9th and 10th Dynasties - the division into two dynasties goes back to the Greek tradition concerning Egyptian history. Many kings followed each other in quick succession. The names of only a few are known, and there are hardly any monuments. In addition to the Herakleopolitans, other kings ruled over southern Egypt from Thebes and in the early 11th Dynasty, which is sometimes included in the 1st Intermediate Period, conflict broke out between the two royal houses. In their inscriptions, the governors of the various nomes and cities not only describe their own achievements as rulers, but also their loyalty to one of the two royal houses. Eventually the Theban king Mentuhotep II succeeded in gaining control over the whole country; it is not clear whether this was a diplomatic or a military victory over Herakleopolis. The 1st Intermediate Period is a period of decay. Not only royal power collapsed, but also that of the government and its many bureaucrats thoughout the land. The quality of the art declined dramatically. Tribes from outside invaded Egypt, and occasionally there was famine. The tombs, pyramids and mortuary temples were plundered, which led to the realisation that no measure was sufficient to guarantee life after death. Despite the omnipresent decay, this was an important mental development. At the same time use of the funerary texts became more widespread. What had previously been a royal prerogative (Pyramid Texts) was now available to an elite level of the population (Coffin Texts). This trend was to continue and would eventually make this textual material available to the poorer levels of the population (Book of the Dead). Towards the end of the 1st Intermediate Period, the artistic production of places such as Gebelein and Asiut once again began to flourish. | <urn:uuid:594a6ce5-4ff8-4382-b934-7c88026035eb> | CC-MAIN-2013-20 | http://www.globalegyptianmuseum.org/glossary.aspx?id=12 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.973921 | 499 | 3.8125 | 4 |
Digital Hearing Aids
The term digital is used for most of today's current technology, from televisions to cell phones. Hearing aids today are also digital, meaning incoming sound is converted into a series of numbers, which is then processed using mathematical equations. Digital processing enables very complex manipulation of sound, for example, to separate speech from noise.
The digital technology within hearing aids also allows to separate sound into different frequency regions and amplify each region selectively, depending on the hearing aid wearer’s hearing loss. The processing within hearing aids also enables different amounts of amplification for soft, moderate, and loud sounds, so sounds are audible, but loud sounds are not uncomfortable or over amplified. And, digital processing enables a natural sound quaity with minimal distortion, resulting in excellent sound quality.
Digital hearing aids are programmable, meaning the hearing aid settings can be precisely fine tuned and special features can be adjusted for each wearer by a hearing aid professional, using special hearing aid software on a computer. Hearing aids are programmed and customized for both the hearing loss and the preferences of the person who wears them.
In addition to basic digital hearing aid technology, many hearing aid manufacturers offer several levels of advanced features made possible with digital processing technology. Digital hearing aids continue to advance and have become much more automatic and are equipped with sophisticated features for people who regularly encounter dynamic listening situations. Examples of of some of these advanced features, what they do and how they benefit the hearing aid wearer are:
- Directional Microphones - Applies preference to sounds in front of the wearer and reduced sound from behind the wearer. This technology has been proven in studies to improve speech understanding in background noise.
- Noise Reduction -Determines if signal contains unwanted background noise and reduced level of background niose if present. Background noise is less annoying and hearing aid wearer's listening comfort is improved in noisy situations.
- Feedback Management - Reduces or eliminates whistling that can often occur with hearing aid use. Hearing aid wearer's comfort is improved from annoying whistling.
- Wind Noise Reduction - Reduces the noise created from wind blowing across the hearing aid's microphone(s). Designed to improve comfort for persons who spend a lot of time outdoors.
- Data Logging/Learning - The ability of the hearing aid to track and learn the hearing aid wearer's preferences in various listening environments. This information can assist the hearing professional in making future programming adjustments and allows the hearing aid to adapt to the wearer's preferences.
- Bluetooth Interface - Establishes a wireless connection between hearing aids and Bluetooth compatible devices. Designed to improve wearer convenience and use with devices such as cell phones, Mp3 players, computers, etc. | <urn:uuid:a3edb3c9-f318-452c-8b24-fdcc36e22e8c> | CC-MAIN-2013-20 | http://www.healthyhearing.com/content/articles/Hearing-aids/Types/166-Digital-hearing-aid-technology-lib | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.923398 | 545 | 3.59375 | 4 |
Scientists have used microscopic water droplets trapped inside ancient salt crystals to take a peek at the contents of Earth's oceans over time, and have found evidence supporting a radical theory that the oceans have changed over the past 500 million years.
"We're not talking about gigantic changes," says Lawrence Hardie, professor of Earth and Planetary Sciences in the Krieger School of Arts and Sciences and the originator of the theory. "It's not going to suddenly change from what it is today, for example, into something that is very alkaline, but we do see changes in the levels of some of the major chemical components dissolved in ocean water, and these changes may be significant enough to affect marine life forms."
Hardie's theory may help scientists understand the origins of Britain's White Cliffs of Dover and other mammoth chalk deposits around the globe. Geologists know that these chalk deposits were formed from the skeletons of microscopic marine creatures called nanoplankton, but they have had difficulty explaining why the nanoplankton were so abundant when the chalk deposits formed, during an era in geological history known as the Cretaceous (Greek for chalk) period.
"The nanoplankton just went whacko, and because the thinking had previously been that sea chemistry was the same in the Cretaceous, it was hard to understand why," Hardie says. "But my theory suggests that there may have been higher levels of calcium dissolved in seawater at that time."
Calcium is a key ingredient in nanoplankton's skeletons and may have fueled both a boom in their population and an increase in the mass of the average skeleton. Hardie is currently working with Steven Stanley, a paleontologist and fellow Hopkins Earth and planetary sciences professor, to see if they can further solidify the potential link using contemporary nanoplankton and seawater altered with added calcium.
First proposed in 1984 but not published until 1990, Hardie's theory about changing seawater chemistry met with heavy resistance. It links changes in the levels of calcium, magnesium, potassium and sulfate ions dissolved in seawater to oscillations in the rate of sea floor spreading at the mid-ocean ridges. The ridges are areas where tectonic plates are pulling apart, exposing underlying lava, which then cools and forms new sea floor.
"The ruling paradigm on seawater chemistry, its major ions and such, was that there had been no change in the past 2 billion years," Hardie says. "The bulk of geochemists who tackled this problem starting in the late 1950s thought that river water coming into the ocean interacts with sediments in the ocean, and that sort of acts like a chemical buffer system to keep the chemistry of seawater the same forever."
The latest evidence to fortify Hardie's theory comes from a project led by former Hardie student Tim Lowenstein, now a professor at Binghamton University. Lowenstein has been studying microscopic drops of brine in salt crystals from various times in Earth's history. The crystals enclose the tiny drops of brine, known as fluid inclusions, as they form from evaporating seawater.
Lowenstein, Hardie and others examined the chemical content of the inclusions with a scanning electron microscope equipped with an X-ray beam adapted for chemical analysis. They found that Hardie's theory accurately predicted what they would find in the inclusions on the basis of the time in history when the salt crystals formed. They published their findings in Science last month.
For Hardie, the results are a vindication. He feels evidence that all might not be right with the "unchanging oceans" model can be traced as far back as the turn of the 20th century, when the German salt industry hired chemist E.H. van't Hoff, winner of the first Nobel Prize in chemistry, to study some of Germany's massive salt deposits.
"He was trying to get some experimental evidence for how these huge masses of salt formed," Hardie says. "They assumed, like everyone else did at the time, that seawater was constant through time. But they looked at these deposits, and they found that there were very few that looked like they had come from something like today's seawater."
Scientists eventually ascribed the differences to changes that had occurred after the salts were buried. But the 1976 discovery of hot brine springs on a midocean Atlantic ridge started Hardie thinking about another possibility.
Hardie became interested in the springs because "the chemistry of the water that comes out of these springs doesn't look anything like seawater, and it also doesn't look anything like river water."
Oceanographers learned that heat from lava at the ridges was creating convection cells that drove seawater into cracks and crevices in the sea floor and out again at the brine springs. The seawater's trip beneath the ocean floor took out magnesium and sulfate and added calcium and potassium.
Hardie developed a theory that envisioned the chemical content of the oceans as the sum of the input from the sea floor brine springs mixed with the influx of material flowing in from the continents through rivers.
"It's a simple model, really, but those are the best ones," he says. "There's no heavy math; it's really nothing more than bean counting."
Using other geological evidence to assess changes in the rate of sea floor spreading, Hardie made predictions for seawater composition at several points in geological history. He previously tested these predictions against evidence found in samples of ancient limestone, salt and other "evaporites."
"Astonishingly, this very simple model does a pretty good job. It gets the boundaries in time between changes in ocean chemistry pretty darn close, give or take 10 million years," he says. Acknowledging with a laugh the irony such a statement carries for nongeologists, he adds, "which for us is pretty close."
Funding for this research was provided by the National Science Foundation's Earth Science Program. Other authors on the Science paper were Michael Timofeeff, Sean Brennan and Robert Demicco, all of Binghamton University. | <urn:uuid:e0519796-fd07-49e8-96bf-6f3c17cc4a7c> | CC-MAIN-2013-20 | http://www.jhu.edu/~gazette/2002/07jan02/07ocean.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.96778 | 1,253 | 4 | 4 |
Video 15: Writing Across the Curriculum
Watch the 30-minute video "Writing Across the Curriculum." If you prefer to watch the video in segments, you can stop at the times suggested below or use the Video Guide (PDF) a detailed outline of the video to help you determine places to stop for discussion.
Answer the questions that follow each segment, jotting down your answers in your notebook.
Error - unable to load content - Flash
Writing Authentically in Content Areas
In the first segment, Katie Wood Ray and Christine Sanchez point to the importance of teaching students to write in a variety of forms and for many purposes.
- What do you imagine the writer's notebook of a mathematician might look like? A scientist? A historian?
- What kind of writing, learning, and questioning might you find in these notebooks?
Preserving Student Choice When Writing in Content Areas
In the final segment, Nicole Outsen encourages her students to choose their own writing topics within the parameters of a social studies unit on the Lewis and Clark expedition and a writing unit on newspaper articles.
- What are the possible benefits of allowing students freedom of choice when writing in various content areas?
- What are some possible genres that students might choose when writing about science? Social studies? Mathematics? | <urn:uuid:575057ac-c4a7-4dc6-a653-bad871babb81> | CC-MAIN-2013-20 | http://www.learner.org/workshops/writing35/session8/sec2p2.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.877838 | 264 | 3.78125 | 4 |
Part 1 - Weapons and Mountings
By Tony DiGiulian
Updated: 16 April 2013
Naval Guns are usually classified by "caliber" (diameter of the bore), "calibers" (length of the barrel described in multiples of the diameter of the bore) and a "Model" or "Reference" designation. Some nations include a modification designation to indicate a change from the original design.
For example, the description: USN 16"/50 Mark 7 Mod 0 means that the gun was developed by the Navy of the United States of America, has a bore 16 inches (40.64 cm) in diameter, a barrel length of 16 x 50 inches = 800 inches (20.320 m) long and is the seventh version of the 16 inch gun with no modifications to the original Mark 7 design.
The way barrel length is measured may differ
between nations and sometimes gun types. Please see Barrel Length
/ Bore Length below. Generally speaking, the longer the barrel,
the more powerful is the gun.
Gun and Mounting Designations of the Major Naval Powers
In the latter half of the 19th century, British cannon designs made a gradual transition from muzzle loading rifles (MLR) to breach loading rifles (BLR, later shortened to just BL). Any breech loader of that period which could fire faster than about two rounds per minute was known as a "quick fire" (QF) cannon, whether it used bag ammunition or cartridge ammunition. However, by the early part of the twentieth century, the BL designation was given only to bag guns while the QF designation was used only for cartridge guns. This separation into BL and QF categories was carried into the designation system, with BL and QF guns of the same caliber being enumerated into different numeric series. Except in gun lists, QF guns were not usually further subdivided into separate and fixed ammunition types. Gun designations during this time were per the diameter of the bore in inches or, for smaller guns, by the nominal weight of the projectile in pounds. A few guns, mainly those developed abroad, were designated by the manufacturer and the bore size in millimeters, such as the Bofors 40 mm and the Oerlikon 20 mm. The bore size was followed by the BL or QF designation and a Mark number using Latin numbers, sometimes followed with one or more asterisks or stars which indicated minor modifications to the original design. For example, the designation 4-in QF Mark XVI* meant a cartridge gun firing a 4 inch (10.2 cm) projectile, with the design being the sixteenth gun in the 4-inch QF series and having had one minor modification to the original design.
Official documents generally follow the nomenclature sequence described above. However, gun breeches were usually engraved slightly differently, with the BL or QF designation being first and then the bore size and mark number following along with a Wire or Steel designation denoting the construction method (see "Wire-Wound" and "Built-up" below). In addition, official documents for gun calibers that never had QF versions almost invariably omit the BL designation. For example, the famous 15-in Mark I is seldom shown with a BL designation, as all 15 inch (38.1 cm) guns were bag guns. Likewise, a few cartridge guns had the QF designation omitted for similar reasons, such as the 20 mm Oerlikon guns.
Many, but not all, larger-caliber weapons designed for the British Army were given mark numbers in the same series as naval guns of that caliber, a practice which occasionally leaves a "hole" in the naval mark number series. I do not usually include a data page for such Army-only weapons, but instead put a "Nomenclature Note" on an appropriate datapage to account for these "missing" mark numbers.
For guns with fractional inch bores, the British practice in official documents was to place the decimal point directly under the inch symbol followed by the tenth inch value, a combination not readily reproducible with modern type fonts. Roughly, this would appear as 4."5 for a 4.5" (11.4 cm) gun. For clarity, I show all such designations as 4.5" (11.4 cm).
Naval mountings had a separate designation, usually incorporating the type of mounting into the designation, and enumerated by the gun caliber. For example, the mounting designation 4.7-in CP Mark XIV meant that the mounting was for 4.7-inch (12 cm) guns, was a "Center Pivot" type, and was the fourteenth mounting in the CP series used for 4.7-inch (12 cm) guns. Similar to guns, asterisks were used to show modifications to the original design, with each additional asterisk identifying a separate modification. A few smaller mountings were designated by their total weight. For example, the 12-pdr 18-cwt was a designation given to a mounting for a 3-inch (7.62 cm) gun firing a 12-pound (5.4 kg) projectile and the gun and mounting together weighed 18-hundredweight or about 2,016 lbs. (914 kg).
Up until shortly after the end of World War II, British weapons were almost always known by their gun designation and not by the designation of the mountings in which they were used. For example, the designation of the 15-in Mark I was for the gun itself, not for its mounting. However, in 1950 the British weapon nomenclature system was changed such that weapons were now known by the designation of the mounting that they were used in and not by the designation of the gun itself. At this same time, Roman numerals were dropped in favor of Arabic numerals.
Some confusion was created under this new designation system as many older weapons were redesignated, even though the weapons and mountings themselves did not change. For example, the weapons used on the Daring class destroyers of the late 1940s were 4.5-in Mark V guns and these were used in 4.5-in Mark VI twin mountings. Under the old nomenclature system, these weapons were referred to as being the 4.5-in Mark V, in other words, by the designation of the gun itself. Under the new system, the guns and mountings together were now referred to as being the 4.5-in Mark 6, which had previously been just the mounting designation. In an effort to reduce confusion, both the original and subsequent designations are given on my data pages for these redesignated weapons, with the newer designations shown in parenthesis.
Under this new nomenclature system, modifications were also now given arabic numerals rather than asterisks, although asterisks were brought forward for those guns having had additional modifications after being redesignated. For example, the 4.5-in Mark IV guns and 4.5-in Mark V mountings taken from scrapped "C" class destroyers and then modified and reused on the Tribal class frigates (Type 81) built in the 1950s were now designated as 4.5-in Mark 5* Mod 2. This designation meant that these mountings had been modified once prior to the change to arabic numbers and then modified twice more after the change.
Weapons designed post-war were designated with an N (apparently for "Navy") such as the 6-in QF N5 guns used on the Tiger class cruisers in Mark 26 twin mountings.
After Britain adopted the metric system in 1965, naval guns and mountings were reclassified in metric units, although English units are still commonly used for many weapons even to the present day.
Note that none of these designation systems include barrel length (calibers) in the designation. For purposes of clarity, I have included barrel length for all gun designations on my British data pages, but strictly speaking, it is incorrect to do so.
Additional information may be found in
the Naval Technical
Board essay Pounders!
Individual guns are identified by the bore in millimeters, the length in calibers of the bore and the year design was started. For example, the designation 380 mm/45 Mle 1935 (Mle = Modèle or "Model") meant a gun whose design was started in 1935, fired a 38 cm (14.96-inch) projectile and whose bore length was 38 x 45 cm long - 17.100 m (673 inches). Mountings were designated with the Model Year, for example, M1932.
Some USA weapons were in French service
for a brief period following World War II, but most have been produced
by France and follow the above designation system.
The methodology of German Naval Gun designations changed three times in the first half of the 20th century. In the period before and during World War I, German guns were designated by their bore diameter in centimeters, "SK" meaning naval cannon, and their nominal overall length in calibers. So, for example, the designation 30.5 cm SK L/50 meant a naval gun firing 30.5 cm (12.008-inch) projectiles with a barrel whose overall length was 30.5 x 50 cm long - 1525.0 cm (600.4 inches). The second method was for guns designed in the period between 1920 and 1940 where the length figure was dropped in favor of the Construction Year (Model Year). For example, under this nomenclature system the guns carried by the Bismarck were designated as 38 cm SK C/34. This designation meant that these were naval guns firing 38 cm (14.96-inch) projectiles whose design was begun in 1934. The third method was adopted in 1940 and under this system guns were designated by their bore in centimeters, "KM" meaning naval cannon and the Construction Year. For example, the designation 10.5 cm KM44 was for a 10.5 cm (4.1-inch) naval gun designed in 1944.
Note that neither of these last two systems included barrel length (calibers) in the designation. For purposes of clarity, I have included barrel length for all gun designations on my German weapons data pages, but strictly speaking, it is incorrect to do so for weapons designed after 1918.
Gun Mountings were designated with the type of mounting and the Construction Year. For example, the designation Drh Tr C/25 was for a turret mounting whose design was started in 1925.
Many postwar guns are foreign designs and are commonly known by the designation given by the producing nation.
Additional information may be found in
Ammunition, Guns and Mountings Definitions.
Prior to the 1920s, most large caliber guns and many smaller caliber guns were imported from Britain. For that reason, most of these guns were designed and designated in inch units. Guns developed in Italy after that time were identified by their bore in millimeters, the length in calibers of the bore and the year design was started either on the gun itself or on the mounting. For example, 135 mm/45 Model 1938 was the designation given to the guns used on the "Capitani Romani" class small cruisers and these were used in Model 1938 turrets. Often the manufacturer's name was also included as part of the designation. Mountings designed by the Italian Navy rather than by a manufacturer were given an RM designation, which stood for "Regia Marina" (Royal Navy).
Some USA weapons were in Italian service following World War II, but most post-war guns have been produced by Italian armament firms and generally follow the above designation system.
It should be noted that many Italian-produced
naval guns even to the present day have been to English measurement units,
not metric. For example, the main guns on the Littorio class battleships
had a bore of 381 mm (15.00 inches), not 380 mm (14.96 inches) as did their
French and German contemporaries. Likewise, the modern-day 76
mm Compact has an actual bore of 76.2 mm (3.00 inches).
The formal gun designation dating from the beginnings of the Imperial Japanese Navy was made up of the barrel or bore length in calibers (kôkei), a type or year type (shiki or nen shiki) which was based upon the original design date of the breech mechanism, the bore diameter and finally the suffix hô (gun). For example, the designation 40 kôkei 11 nen shiki 14 cm hô (40 caliber 11 Year Type 14 cm Gun) would mean a 14 cm/40 (5.5 inch) gun whose breech design was initiated in the 11th year of the Taishô regnal era (1922 A.D.). Imported weapons had an additional designation to indicate the manufacturer.
Following the methodology of their British mentors, bore length was measured starting from the top of the mushroom head (vent axial) of the breech block for bag guns and starting from the inner breech face for cartridge guns. For a few guns, the bore length designation was actually the overall length of the barrel rather than the bore length. Unlike the British, the Japanese did not separate guns of the same caliber into bag and cartridge types.
Prior to 5 October 1917, the bore diameter was measured in English units. Guns with fractional inch bores followed British practice and were designated such as 4 in 7 (4.7 inch - 12 cm) and 5 in 5 (5.5 inch - 14 cm). For clarity, I list these as decimal values, in these instances as 4.7" (12 cm) and 5.5" (14 cm). On 5 October 1917, the Japanese Navy converted to the metric system and most naval guns were then designated with the bore diameter rounded up or down to a whole centimeter number, but not necessarily to the nearest value. For example, 3.0-inch guns were designated as 8 cm rather than 7.62 cm and 16.1-inch guns, originally designated in 1917 as 41 cm, were redesignated in 1922 as 40 cm. However, 5.0-inch guns were designated "correctly" as 12.7 cm rather than "incorrectly" as 13 cm. This may be a good place to note that anyone seeking consistency in Japanese ordnance designations is doomed to disappointment.
The shiki and nen shiki designations (Type and Year Type, which can be considered as being somewhat analogous to a Model Year) are quite complicated. On 25 December 1908, which was the 41st year of the Meiji regnal era, all guns in service in the Imperial Navy were redesignated. Weapons that had been manufactured by the Japanese were designated as 41 shiki hô (41 Type gun or Model 1908) even though most of them had been designed and produced prior to 1906. Guns developed after this time were assigned Year Types based upon when the design of the breech mechanism was begun. Two different calendar systems were used to define the Year Type. Between 1908 and 1927, the Year Type was based upon the year of the current regnal era, followed by the suffix nen (year), such as 11 nen shiki (11 Year Type or Model 1922). Those guns produced between 1927 and 1939 were assigned Year Types using the last two digits of the Imperial Calendar year, which dated from the start of the reign of Emperor Jimmu in 660 B.C., with 1927 A.D. being Imperial Calendar Year 2587. Finally, under the Imperial Calendar system, weapons designed between 2600 and 2605 (1940-45) were designated by using just the last digit of the Imperial year.
The dates in these Type and Year Type designations should be used with caution, as they are not directly equivalent to a Model Year and in fact usually only reflect the date of the first gun design in the series. There are examples of guns with the same Year Type designation having been designed many years apart, especially in the 11 nen shiki (11 Year Type) series. These designations should be looked at as being more equivalent to a "class of weapon" designation rather than as being an actual design date.
It should also be noted that these Japanese Year Type designations do not translate well into English. For example, although a literal translation of 11 nen shiki hô would be 11 Year Type Gun, this sounds "wrong" to English-speakers. For that reason, most English translations of this designation would show it as either 11th Year Type or as Type 11. Neither of these are literally correct translations, but sound "better" to English-speakers. On my data pages, Japanese designations are shown such as 11th Year Type for regnal-era calendar guns and such as Type 94 for Imperial Calendar-era weapons. As noted above, neither of these are literally correct, but I believe them to be more easily understandable by English speakers and better indicate the era in which they were designed.
On my data pages, the Year Type in A.D. is always noted and all known designations that a weapon had during its design and service life are listed.
The gun barrels themselves were designated with a numbering system somewhat similar to the USN Mark and Mod system (see below). The earliest barrel design was designated as Roman numeral I, later minor modifications were given numeric subscripts such as I2, I3, etc. Major changes to the design were given higher Roman numerals, such as II, III, etc. On my datapages, these barrel designations are usually shown such as Model Type I2.
It should be noted that the Japanese Model number system became chaotic towards the end of World War II. New weapons were assigned Year Type designations that had no relationship to the actual date of design, with some apparently chosen simply to fill in missing years in the series. As John Campbell put it, "such are the pitfalls of Japanese ordnance [nomenclature]."
As examples of Japanese designations for naval guns:
Postwar guns are primarily foreign designs and are commonly known by the designation given by the producing nation.
Weapon systems other than naval guns were primarily designated as to when they entered service. For example, the famous Zero fighter plane of World War II derived its name from its designation, Type 0 carrier-based fighter, as its service introduction was in the Imperial Calendar year 2600 (1940).
Additional information may be found in
Ammunition, Guns and Mountings Definitions.
Russia / USSR Designations
Prior to 1917, designations included the
bore size, overall barrel length and the
Obrazets - Pattern (Model)
Year. Guns were designated either by their caliber in inches if it
was a whole number or in millimeters for all others. The Pattern
Year was the date the weapon was accepted into service. After 1917,
a project number was added and all calibers were designated only in millimeters.
As an example of the post-1917 designation system is 130 mm/50 B13 Pattern
1936, which meant that this was a weapon firing 130 mm (5.1-inch) projectiles,
had a barrel 50 calibers long, was designed at the "Bol'shevik" plant as
Project 13 and which entered service in 1936.
United States of America Designations
Up until just after World War II, each caliber of USN guns was identified by its length in calibers, a mark number and a modification number, the original modification designation being "Mod 0". For example, 16"/50 Mark 7 Mod 0 meant a gun firing 16-inch (40.64 cm) projectiles with a barrel 16 x 50 = 800 inches (20.320 m) long, was the seventh gun in the 16-inch (40.64 cm) series and was built to the original design with no modifications. A few smaller guns built or purchased mainly in the latter part of the 19th century were known by the weight of their projectiles; the 1-pounder through 6-pounder. Roman numerals were used for Mark designations until about 1920 when arabic numerals were substituted.
Gun Mod numbers generally indicated changes to the original design for new guns or a change made to a finished gun. For example, a change in the rifling pattern from the original design might be designated as Mod 1 and new guns built with this rifling would be so designated. Guns more heavily modified would be given new Mark numbers, such as the 14-inch (35.56 cm) Mark 4 guns rebuilt during the 1930s and then redesignated as Mark 11 guns.
Mountings originally had a similar designation, being of the form 12" Mark 8 Mod 0 for a mounting using a 12-inch (30.5 cm) weapon. By 1930, the Mark number mounting designation had been dropped for weapons larger than 5 inches (12.7 cm) and new mountings were then known by the ship class they were used on. For example, the mountings for the 16"/50 (40.64 cm) Mark 7 guns used on the Iowa class battleships were designated as 16-inch three-gun mountings Iowa class. Mountings for 5 inch and smaller guns continued to have Mark numbers assigned to them.
Similar to Britain, shortly after World War II the USN designation system was changed from being based upon the gun classification to being based upon the mounting classification. So, a modern designation such as 5"/54 Mark 45 is really the designation of the gun mount, not the weapon itself. Furthermore, starting with the 5"/54 Mark 42, almost all naval guns are now classified into a single "Mark" series, regardless of their caliber. For example, modern guns such as the 5" Mark 45, the 76 mm Mark 75 and the 57 mm Mark 110 are all in the same numeric Mark series.
Additional information may be found in USN Naval Gun Designations.
AA - Anti-Aircraft.
AAA - Anti-Aircraft Artillery. Refers to larger caliber guns used as anti-aircraft weapons, usually any AA gun larger than about 2.5 in (6.4 cm).
AA/Su - Anti-aircraft/Surface. British designation used to denote dual-purpose weapons or fire control systems. This replaced the previous "HA/LA" designation in 1947.
Autofrettage - A process in which a favorable distribution of initial or residual stress in a tube is induced, as in the manufacturing of gun barrels. Literally means "self-hooping" and the process involves expanding a partially machined barrel or liner by applying hydraulic pressure to the interior surface. The metal of the bore is the first to be stretched beyond the elastic limit. The process is continued until the metal at the outer surface just reaches its elastic limit. At this point, the increase of hydraulic pressure in the bore is halted and soon afterwards the pressure is reduced to zero. Since the metal at the bore has received a certain amount of plastic deformation, it would, if left free to do so, retain all of this "set." However, since the metal at the outer surface has received no permanent set, but only a strain within the elastic limit, it attempts to return to its original diameter. The metal between the bore and the outer surface has received some plastic deformation, decreasing outward. The final result is that the bore is forced back to a diameter somewhere between the original diameter and that which was attained under the maximum hydraulic pressure. Thus, the bore has received a certain amount of tangential tension, exactly as in the case of a built-up gun, but with the difference that the autofrettage process results in a indefinite number of layers, each infinitesimal in thickness, and having varying stresses which result in producing the maximum possible strength in the finished gun. This process allows steels with low alloy content to be used to make gun barrels. During the 1920s and 1930s, the US Navy termed this process "manufacture by radial expansion."
Bag Guns - Weapons that used powder bags rather than a cartridge case to hold the propellant. This was the most common ammunition type of the twentieth century for 6 inch (15.2 cm) and larger guns. Guns using powder bags were designated as "Separate Loading" in the USN, a reference to the normal procedure for bag guns of first ramming the projectile and then the powder bags. Smaller calibers generally use a single bag while larger calibers may have as many as six bags. See "Bag Ammunition" on the Ammunition Definitions data page for additional information.
Bayonet Joint - An interrupted-thread method of attaching the gun barrel to the housing in order to make for easier barrel replacements. For many USN guns designed for case ammunition, the housing took the place of the yoke and screw-box liner used on bag guns. This construction method allowed the elimination of the slide cylinder in some weapons.
Barrel Length / Bore Length - One of the more confusing items about gun designations is that the way that the length (calibers) of a gun barrel is measured differs from nation to nation. The USA measured starting from the inner breech face for both bag and cartridge guns. Austria-Hungary (Skoda), Germany and Russia measured the length of the entire barrel. Britain, France, Italy, Japan and Sweden (Bofors) measured starting from the top of the mushroom head (vent axial) of the breech block for bag guns and starting from the inner breech face for cartridge guns. These differing methods have often resulted in nomenclature errors in reference works. For example, the 38 cm SK C/34 guns on the German battleship Bismarck are often noted as being 47 calibers long. Per the German method - overall barrel length - these guns were 51.66 calibers long and per the British/USA method - measured from the inner breech face - they were 48.3 calibers long. As every German document I have seen refers to these guns as being the equivalent of either 51.66 or 52 calibers long, I am not certain why so many authors refer to these guns as being 47 calibers long. My thanks to M.J. Whitley, whose series of books on German Warships of World War II first enlightened me on how the German methods differed from those of other nations. On my webpages, "Gun Length oa" refers to the overall barrel length. "Bore length" is per each nation's specification except where noted.
BL - British designation meaning Breech Loading cannon. In the 1800s the the British used the designation BLR where the "R" stood for Rifle, but after about 1890 the "R" was dropped from new gun designations. By the early part of the twentieth century, BL had become to be used only for bag ammunition guns.
BM - Breech Mechanism.
BMG - Browning Machine Gun. These were recoil-operated machine guns of various calibers originally designed by the USA inventor John Moses Browning (1855 - 1926), the most famous being the "fifty-caliber." The modern version is the 0.50" (12.7 mm) BMG M2HB, with M2HB meaning Mark 2 Heavy Barrel. The M2 designation is why this weapon is often known as the Ma Deuce.
Bolt - The mechanism that positions the cartridge in breechloading guns, closes the breech, and ejects the spent cartridge case.
Bolt Open or Open Bolt - Refers to automatic or semi-automatic weapons that are designed such that the gun bolt is normally held to the rear of the weapon, leaving the breech open. Only after the trigger is activated is the next round pushed into the firing chamber and the breech closed. This design reduces the chances of an accidental "cook off" as no bullet is in the firing chamber until after the trigger is activated.
Bolt Closed or Closed Bolt - Refers to weapons that are designed to hold a bullet in the firing chamber with the bolt closed prior to activating the trigger.
Bore - Inner Diameter (ID) of the barrel. This is measured from land surface to diametrically opposed land surface. For example, the USN 16"/50 (40.64 cm) guns used on the Iowa class battleships had a new gun land to land diameter of 16.00 inches (40.64 cm) while the diameter as measured from the bottom of the groove to the opposite bottom of the groove was 16.30 inches (41.40 cm). "Bore" is also used as a shorthand reference for "Bore Length" - see "Barrel Length / Bore Length" above.
Bore, Squeeze - The bore near the muzzle is slightly reduced in diameter in order to better center the projectile before it leaves the gun. This reduction also flattens out the driving band, thus giving the projectile a better aerodynamic shape. For a related design, see "Probertised" below.
Breech - The rear of the gun. In most 20th century guns, where the shell goes in, hence the name "Breech Loader."
Breech Block, Breech Mechanism or Breech Plug - This is the mechanism at the rear of the gun which closes the bore against the force of the firing charge. For large weapons, such as a battleship's main guns, these are usually of an interrupted-screw construction, which gives a very strong seal. For rapid fire guns, a sliding breech-block is commonly used which may open and close automatically as the gun is fired.
Breech, Four-Motion - Early screw breech design invented by the French where all of the threads were at the same level. Usually there were five or six threaded sections separated by equal width non-threaded sections. These breech blocks were comparatively long as half of the thread was cut away to allow withdrawal, thus reducing their capacity to withstand firing stresses. This type of breech mechanism required that the block be first withdrawn straight back from the gun barrel before it could be moved out of the way of the reloading process and some had to be disconnected entirely from the gun. Closing the breech was a complicated operation, involving four motions: swing the carrier so that the screw could enter the breech, slide the entire breech mechanism forward so as to seat it, turn the screw through part of a turn until the threads meshed with those in the breech, and then lock the mechanism.
Breech, Holmstrom - A type of breech mechanism for bag guns whereby the screw block was operated by a crank that moved parallel to the rear face of the block. Named after the inventor, Carl Holmström.
Breech, Pure-Couple - British Welin Breeches of the early 1900s that used a long, manually operated lever to operate the breech screw. A "couple" consists of two parallel forces that are opposite in direction and do not share a line of action. A couple does not produce any translational movement, only rotation. A "pure couple" always consists of two forces that are equal in magnitude. So, a "pure couple breech mechanism" is one that uses and produces rotational force in order to work the breech plug. See "Breech, Welin" below.
Breech, Single-Motion - See "Breech Mechanism, Smith-Asbury" below.
Breech, Three-Motion - Similar to a Four-Motion Breech, except that the breech was withdrawn into a hinged carrier ring. This meant that the motions were reduced to unlocking, withdrawal and then swinging out of the way.
Breech, Welin - A stepped-thread breech developed during the 1890s and named after the inventor, Axel Welin, a Swedish Ammunition Engineer then residing in London. A Welin breech block has only one third or one quarter of the threads removed, which means that a shorter screw length can be used to obtain the same strength as a four-motion breech mechanism. See the "breech plug" in the illustration above for a typical Welin design. Unlike the four-motion breech, a Welin breech allows the mechanism to be simply unscrewed and swung out of the way, it does not have to be withdrawn straight back from the gun barrel. Variations of the Welin Breech design were used on most bag ammunition guns of the twentieth century.
Breech Block, Vertical Sliding-Wedge - Used on many cartridge guns, this sort of breech mechanism slides vertically in grooves cut in the housing. After the cartridge is inserted, the breech block slides up with the sloping part of the forward face wedging the cartridge home in the chamber. An extractor mechanism catches the cartridge case rim as the breechblock drops after firing, pulling the expended cartridge case out of the gun. A few guns use a similar design, but with the breechblock sliding horizontally. These, of course, are known as "Horizontally Sliding-Wedge" breechblocks.
Breech Mechanism, Smith-Asbury - Introduced in 1916 and named after its inventors, Lt. Cmdr. George Leonard Smith, USN and Draftsman Dorsey Frost Asbury, both of the Naval Gun Factory at the Washington Navy Yard. This mechanism used gearing to fully open a Welin breech by linking the unscrewing, withdrawing and swinging clear movements into one continuous action and for that reason is sometimes known as a "single motion" breech mechanism. The breech threads are undercut at the start so as to allow the block to swing into position.
Built-up Construction - Guns that are manufactured from multiple hoops (tubes) which are joined together with locking rings and overlapping sections to make longer and/or thicker sections. This was the most common process for manufacturing almost all guns until the 1920s when monobloc techniques were introduced for guns smaller than about 6 inches (15.2 cm). See "Monobloc" and "Wire-Wound" below.
Caliber and Calibers - "Caliber" refers to the bore diameter of the gun barrel or to the diameter of the projectiles fired. "Calibers" refers to the length of the gun barrel in multiples of the projectile diameter.
Cartridge Guns - Weapons in which a metallic container, usually brass or steel, is used to hold the propellant. Most commonly used for "Quick Firing" and automatic weapons.
Chamber - Part of the gun in which the propellant charge is placed. In a bag gun, that space between the obturator or breechblock and the forcing cone. In fixed or semi-fixed ammunition, the space occupied by the cartridge case.
Chamber, Fluted - Small longitudinal channels cut in the chamber walls, used in many semi- and fully-automatic weapons. When the cartridge is fired, these channels allow a small portion of the propellant gases to get between the cartridge case and the chamber walls, preventing the cartridge case from "sticking" to the chamber walls, thus making it easier to extract.
Chamber Size - Space available for gas expansion when the projectile is seated in position; measured from the face of the closed breech block, around the base of the projectile, to the rear of the rotating band (or obturator). In fixed ammunition, it is the volume of the cartridge case behind the projectile.
Chrome Plating - In the 1930s, the USN started to chrome plate the bores of most guns to a depth of 0.0005 inches (0.013 mm). This was "hard chrome," which is not the kind that you find on your father's Oldsmobile. This plating increased barrel life by as much as 25%. The plating generally extended over the length of the rifling and shot seating. Chrome plating has also been found to reduce copper deposits.
CIGS - Close In Gun System. A weapon system designed to combat small boats at short ranges - the "Boghammer" threat.
CIWS - Close In Weapons System. A weapon system designed to combat anti-ship missiles or aircraft at short ranges.
Cup Obturation - I cannot possibly improve upon Mr. Ruffell's description (Off-Site at Royal New Zealand Artillery Comrades Association).
cwt - Hundredweight. British unit of measurement that was used to designate smaller weapons by the weight of the gun and mounting. One hundredweight is 112 pounds (50.8024 kg).
De Bange Obturator System - See "Obturator" below.
DEF - Direct Electric Firing, usually abbreviated as "E." British gun prefix designation meaning that the gun was fired by electric arcing.
DP - Dual Purpose. These guns are intended to be used against both surface and aircraft targets. Maximum elevation of these guns is usually greater than 50 degrees.
EMF - Electro Mechanical Firing, usually abbreviated as "F." British gun prefix designation meaning that the gun was fired by electromotive force, i.e., a solenoid activating a striker pin.
EFC or ESR - A means of estimating the remaining accuracy life of a weapon. Accuracy life for a gun or liner is usually expressed as "EFC" meaning Equivalent Full Charges or as "ESR" for Equivalent Service Rounds. On my webpages, this is the number specified. A gun or liner has reached the end of its accuracy life when the projectiles and propellant charges assigned for its use give range patterns that exceed an arbitrarily adopted size, generally something like 10 percent larger than those with a new barrel. For large caliber guns, life is roughly the same as the number of AP shells that can be fired with full charges before the barrel needs to be replaced or relined. Compared to rounds fired with full charges, Practice Rounds and shells fired with reduced charges generally cause less wear, while proof charges and super charges cause more wear. The amount of wear immediately forward of the origin of the rifling is the most important value used in determining the remaining life. The three main causes of bore erosion are thermal stress, mechanical wear and chemical erosion. The greatest source of wear is from the propellant gasses, which corrode the rifling via heat and chemical action.
FER - Fatigue Equivalent Rounds. The mechanical fatigue life of a gun barrel or liner expressed as the number of mechanical cycles the gun barrel or liner can withstand before needing to be replaced. This has replaced EFC/ESR for some modern weapons.
Firing Lock or Primer Chamber - A feature of the breech mechanism used for bag guns, this is a small enclosure into which the igniter or primer is inserted. See "Primer vent or vent axial" below.
FLAK - FliegerAbwehrKanone. German designation for AA weapons (FLAK guns). Literally means "Flier Defense Cannon." During World War I, this term was used by Allied airmen to describe the shell bursts from such weapons, which has become the current accepted meaning of the term.
Forcing Cone or Seat - The forward end of the gun chamber where it necks down to the start of the rifled portion of the barrel. This guides the projectile as it is being rammed.
GAU - US Military designation for airborne guns and gun systems.
Grooves - A rifled gun is so called on account of the spiral grooves which are cut into the surface of the bore and into which the soft metal projectile driving bands are forced during its travel down the bore. See "Rifling" and "Twist" below.
Grooves, Plain-Section - A rifling pattern where the bottom of each groove is concentric with with the bore and the sides of which terminate in a small radius.
Grooves, Hook-Section - A rifling pattern which has a "driving" side which exerts a high pressure on the projectile driving band while the other side of the groove has a gentler slope which exerts little pressure on the driving band. In a gun with RH twist, the driving side is on the right hand side.
GWS - Gun Weapon System.
HA - High Angle. British designation used to denote DP or AAA guns or directors. Meant that the gun could be elevated past about 50 degrees or that the director was intended for AA use. Replaced by "AA" in 1947.
HA/LA - High Angle/Low Angle. British designation of World War II equivalent to DP. Meant that a gun or director was intended for use against both surface and aircraft targets. This designation was replaced by AA/Su (anti-aircraft/surface) in 1947.
Hoop or Tube - A section of the gun barrel. See "Built-up Construction," "Monobloc Construction" and "Wire-wound Construction."
Hornrings - Rings shrunk onto German heavy guns to which the piston rods of the recoil and run-out cylinders were attached.
IV - Initial Velocity. Velocity of the projectile upon leaving the barrel of the gun. Equivalent to "Muzzle Velocity."
KM - Kanone Marine. German for "Naval Cannon." Usually followed by the model year. For example, KM42 meant a naval gun designed in 1942. This designation system was used for some guns designed between 1940 and 1945.
LA - Low Angle. British designation used to denote SP guns or directors. Means that they are intended for use solely against surface targets. Replaced by "Su" for surface in 1947.
Lands - The bore surface between rifling grooves inside the gun barrel. See "Rifling," below.
Life - See "EFC or ESR," above.
Liner - A replaceable tube within the gun barrel. The useful life of a gun is measured by how much rifling remains. By having the rifling milled into a replaceable liner, the life of the gun barrel itself is increased by many times. A "Loose Liner" or "Loose Barrel Construction" means that the gun was built with a small clearance between the outer diameter of the liner and the inner diameter of the next outer part. When firing, the gas pressure elastically expands the liner but otherwise the clearance remains. This method of construction makes it easy to replace the liner after removal of the locking devices. The replacement method for standard liners is much more complicated. The USN used a "gun pit" into which the barrel was lowered. Heat was then applied to the outside of the barrel while cold air was pumped through the bore. The result was that the barrel expanded while the liner contracted, thus opening a small clearance around the liner. The liner could then be extracted from the barrel. Liners are usually coated with graphite in an effort to ease assembly and disassembly.
Locking Ring - A short cylindrical casting used for joining gun barrel tubes together. See "Hoop" above.
MG - Machine Gun.
MK or Mk - Abbreviation for "Mark."
MLR - British designation meaning Muzzle Loading Rifle.
Monobloc Construction - A gun built from a single tube apart from the breech-ring and breech mechanism rather than a multi-tube built-up design. During the 1920ís, when centrifugal spun castings came into being, it became possible to make cylindrical castings with a precise wall thickness and density with no cracks. The inside diameter of these spun castings could be controlled to the point where very little machining had to be done to true-up the inside diameter. The general process was to make three tubes; the gun barrel itself, the breech ring and a liner, which together made up the gun barrel. These three tubes were assembled onto each other, usually by autofretting techniques, with the breech ring making a thicker and thus stronger section at the breech end of the gun. Later designs for guns smaller than about 6 inches (15.2 cm) further simplified the manufacturing process by eliminating the separate liner. Monobloc construction makes for a straighter, stronger barrel than does built-up construction and overcomes some of the problems with having to make one solid casting with a thickening at the breech. This older style of casting had cooling problems due to the uneven wall thickness which could lead to cracks developing.
Mushroom head - A component of Welin breech-blocks, this is the forward part of the breech-block, between the chamber and the obturator. See the diagrams for the "Breech-block" and "Obturator."
Muzzle - The fore or "Business End" of the gun. Where the shell comes out.
Muzzle Bell or Swell - Many guns have a barrel thickening at the muzzle. This is meant to strengthen the gun barrel at the muzzle and so prevent the guns from splitting. This feature is also known as the muzzle "tulip", "lilly" or "flare." Modern weapons use higher quality steel and so lack a bell, or instead have lugs, which are utilized when the liner is replaced (the lugs serve to anchor the tool used for pulling the liner out).
Muzzle Brake - A device on the muzzle which diverts part of the propellant gasses to the sides or rear in order to reduce the recoil force.
Muzzle Droop - As in any unsupported structure, a gun barrel bends due to the action of gravity. The vertical distance that the muzzle end of a gunbarrel moves from its "ideal" position is called droop. Gun barrels are usually orientated in their mountings in the direction that produces the least amount of droop.
MV - Muzzle Velocity. The velocity of the projectile as it leaves the gun barrel. Equivalent to "Initial Velocity."
Nendo Shiki - Japanese for "Year Type." See "Japanese Designations," above.
Obturator - For breech loading guns, this is a device for making the breech gas-tight, preventing any escape of propellant gas while the breech is closed. For bag guns using Welin breech blocks, the De Bange obturator system (named after Captain de Bange of the French Army, who invented it in 1872) was commonly used. The De Bange obturator system consists of a doughnut-shaped washer pad, also known as a "gas check pad," that is located between the mushroom head and the screw breech. See the breech illustrations for details. When the breech is closed, rotating the screw squeezes the pad against a conical section of the gun barrel. When the gun is fired, the mushroom head is driven back against the pad which forces it tighter into the conical seating and thus seals the barrel. For guns using cartridge ammunition, the cartridge case itself becomes part of the obturator system. Generally speaking, both the cartridge case lip and cartridge case mouth are used to seal the barrel. The cartridge case lip is forced tightly against the breech when closed while the chamber of the gun is designed such that the expansion of the mouth of the cartridge case when the gun fires helps to seal the barrel. Also see "Obturator" under Projectile Definitions.
Pdr. - A way designating weapons in terms of the weight of the projectile they fired. For example, the British 2-pdr. AA gun fired a shell weighing about two pounds (0.9 kg). For reasons that can only be described as traditional, the British, alone of all modern nations, clung to this method of designation well into the twentieth century, long after other nations had switched to designating weapons by their bore diameter.
Pom-pom - This term originated with the British 1-pdr. used during the Boer War and was later applied to the 2-pdrs. of World War I and II. Reportedly, this was the sound made by large automatic guns when firing.
Primer Channel - See "Firing Lock" above.
Primer Vent or Vent Axial - A feature of the breech mechanism used for bag guns, this is a hollow tube running from the firing lock or primer chamber through the stem to the front of the mushroom head. When the igniter or primer is fired, it generates a flame which travels through this tube into the propellant charges. See the above obturator illustration.
Probertised - A gun barrel where the rifling grooves near the muzzle gradually disappear until the last section of the barrel becomes smoothbored. When a projectile travels through this section, its driving bands get flattened against the shell body, giving the projectile a smoother shape and thus improving its aerodynamics. Named after the inventor, British Colonel Probert of the Woolwich Arsenal.
QF - British designation meaning Quick Firing cannon. In the late 19th and early 20th centuries, this term was used to define any gun that could be fired several times per minute whether it used bag or cartridge ammunition. By the 1920s this designation was given only to guns that used metallic cartridge cases.
QFC - Quick Firing, Converted. Early British Bag guns modified to use cartridge cases.
Receiver - The main portion of the weapon, to which the barrel and operating mechanism are attached.
Rib-Rifling - Rifling pattern where the grooves are very wide and the lands are very narrow. Lands are known as Ribs for this kind of rifling.
Rifling - The bores of most gun barrels have grooves milled into them in a spiral pattern. These grooves engage the Driving Bands on the projectiles and thus impart a spin to them as they leave the barrel. Spinning the projectiles makes them more stable in flight which greatly increases their accuracy and range. It also makes them more likely to land nose first, which is very important for an armor-piercing shell. The way the grooves are milled varies greatly. Some manufacturers prefer a uniform pattern, others prefer grooves that vary in depth and width as they progress through the weapon. See "Twist" below.
RF - Rapid Fire. USN term equivalent to QF during the end of the 19th century and first half of the twentieth century. At the end of World War II, this term was used to describe large caliber guns with automatic shell-handling equipment such as those carried by the USS Des Moines (CA-134) class heavy cruisers.
ROF - Rate of Fire. Usually shown in terms of RPM - Rounds per Minute. ROF may be affected both positively and negatively by many different elements, too numerous to list here. ROF figures given on my data pages for manually-operated guns represent nominal values and should not be interpreted as being literally correct under all circumstances. ROF figures on my data pages for automatic weapons are usually the cyclic values, with practical values given where possible. It should be noted that an air-cooled automatic or semi-automatic gun can be fired continuously at its maximum cyclic rate for only a short period, otherwise its barrel will start to soften or melt. Automatic guns using a water jacket, especially those with a recirculation method including a radiator, may fire continuously at their maximum cyclic rate for much longer periods, as the cooling water helps to keep the barrel below the melting point.
rpgpm - Rounds per gun per minute. The rate of fire of each gun in a multiple gun mounting.
RPM - Rounds per Minute. On my data pages for multiple gun mountings, this is always listed in terms of rpgpm.
Screw box liner - The barrel sectional casting to which a screw breech block screws into when closing. Known as the "breech bush" in British weapons.
Sear - Holds the firing pin in a cocked position against the compression of a spring until the trigger is activated, which allows the spring to drive the firing pin into the primer.
Separate Loading - See "Bag Guns" above.
SF - Slow Firing. This may not have been an official designation, but instead may have been a way of differentiating those guns that were not "QF" or "RF" types.
SK - Schnelladekanone or Schnellfeurkanone. German for "Fast Firing Cannon," equivalent to QF or RF. Also listed as being for "Schiffskanone" or "Ship Cannon." See "German Designations" above.
Slide cylinder - The part of the gun forward of the rear cylinder which fits in the slide and moves through it during recoil. Keys are usually inserted between the slide and the slide cylinder to prevent rotation of the gun due to the reaction of the projectile on the rifling. See "Slide" below.
Smoothbore - A gun barrel or gun barrel section that does not have any rifling.
SP - Single Purpose. Means that the weapon is intended for use only against surface targets. Maximum elevation of these guns is usually less than 45 degrees.
STAAG - Stabilized Tachymetric Anti-Aircraft Gun.
Su - Surface. British designation for SP guns. This replaced the previous "LA" in 1947.
Stabilized - When a mounting is referred to as "stabilized," it means that it contains some method for correcting for the deck inclination caused by the rolling and pitching of the ship. Usually, this involves more than two axis of motion (traverse, elevation) and requires gyroscopes.
Striker Gear - The firing pin and associated mechanisms used in percussion firing.
Tampion or Tompion - A plug that goes into the muzzle of the gun. Keeps the sea spray out of the barrel. In the USN, pronounced "tom-kin."
Taper wound or Taper winding - British method of wire-wound gun construction in which a single length of wire is used rather than multiple lengths. Introduced following World War I. See "Wire-wound Construction" below.
TBK - Torpedoboots Kanone. German for "Torpedo Boat Cannon." Also shown as Tbts K.
Trunnion - The cylinders upon which the gun barrel pivots up and down.
Tube - Gun barrel section. See "Built-up Construction," "Monobloc Construction" and "Wire-wound Construction."
Twist - Rifling grooves make a spiral towards the gun muzzle. The length of the barrel necessary for the grooves to make one complete revolution is called "Twist." This is usually expressed in calibers but sometimes appears in measurement units (inches or meters). On my data pages, Twist is specified in calibers, with "RH 1 in 25" meaning that, when looking at the top of the barrel from the breech end of the gun, that the spiral goes in a right-hand direction and that it takes 25 calibers for the grooves to make one complete revolution. Depending upon the internal ballistics desired, the spiral may be of a uniform pattern, where the angle of inclination remains constant throughout the bore, or it may be of a parabolic pattern with the twist increasing as it nears the muzzle. The steepness of the twist is related to the length and weight of the projectiles fired. Twist is intended to make a projectile spin at a stabilizing rate as it exits the barrel. Generally speaking, a longer, heavier projectile must spin faster than a shorter, lighter projectile in order to remain stable in flight. As a rule of thumb, a projectile fired from a smaller caliber gun spins close to 100% of the rate determined by the muzzle velocity divided by the twist length. By contrast, due to slippage caused by inertia, large-caliber projectiles spin at about 90% of the rate determined by the muzzle velocity divided by the twist length. As an example of calculating spin rate, for a 16 inch (40.64 cm) gun with a uniform twist of 1 in 25, the barrel length required for the twist to make one full rotation would be 16 x 25 = 400 inches or 33.33 feet (10.16 m). Nominally, this twist would mean that a projectile with a muzzle velocity of 2,500 fps (762 mps) would be rotating as it left the muzzle at about 75 RPS or 4,500 RPM, but because of slippage it is actually rotating at about 67.5 RPS or 4,050 RPM. Because of gyroscopic and corolis effects, a shell fired from a gun with RH twist will tend to drift to the right while one fired from a gun with LH twist will drift to the left. Drift due to the corolis effect is near zero at the equator and at its maximum at the earth's poles. The amount of drift is also affected by the direction of fire. Fire control systems have input settings for the ship's latitude and the direction of fire so as to correct for these effects. Note: I have never found a naval cannon with LH twist, they all have RH twist. I have found a few small-arms that use LH twist, including the famous Colt black-powder pistols of the mid-1800s, but most small-arms use RH twist.
UBK - Untersee-Boots Kanone. German for "U-boat Cannon." Also shown as "Ubts K."
Water-cooled - A weapon which uses a water-jacket around the gun barrel. These are used on machine guns and rapid-fire weapons in order to keep the barrel from softening or melting during prolonged firings. The development of higher-quality alloys in recent years has reduced or eliminated the need for water jackets on many newer weapons.
Wire-wound Construction - A method of strengthening built-up gun barrels by using long lengths of wire wrapped around an inner tube. This method of construction was used extensively by the British roughly between 1880 and 1925. Few nations other than Japan adopted this technique as it greatly complicated the manufacturing process. The wire was about 0.1 inches (2.5 mm) thick and had a rectangular cross-section or was sometimes ribbon-shaped. The wire was quite strong with tensile strengths of up to 200,000 psi (14,000 kg/cm2) and very long lengths of wire were used. For example, the British 15-in/42 Mark I used about 170 miles (274 km) of wire on top of the "A" tube. A "B" tube was then shrunk on overtop the wire-wound section. It should be noted that wire-winding strengthened the gun barrel only in regards to resisting the gas pressure generated by the burning propellant. There is some controversy as to whether or not this type of construction weakened the overall barrel strength and increased the amount of muzzle droop. The British gradually replaced wire-winding construction with monobloc and built-up construction techniques and by 1930 no longer used it all. The last Japanese weapon using wire-winding was the 46 cm Type 94 guns used on the Yamato class battleships.
Working Pressure - The pressure generated inside the barrel by the burning propellant. This pressure is measured at the breech of the gun. Because of the pressure gradient in the barrel, the peak pressure at the base of the projectile is at a smaller value. A reasonable rule of thumb is that the pressure at the breech is between 1.16 to 1.2 times greater than the pressure seen at the base of the projectile. It should be noted that the pressure values found in reference works for older guns are not particularly accurate. Pressure was measured by the size of a copper cylinder that was crushed when the gun was fired. The size of the cylinder crushed was converted to "copper units of pressure (CUP)." Historically, the chamber pressure for U.S. Naval guns has been specified in long tons copper per square inch (tsi). To convert to true pressure, the copper tsi is multiplied by 2.688 to get pounds per square inch (psi). The copper cylinder method has been made obsolete by the invention of piezoelectric strain gauges which have made pressure measurements much more precise. Copper tubes are still used by both the US Army and Navy for tests where only peak pressure testing is required, such as for barrel proof or ammunition lot acceptance. Modern smaller caliber guns are usually rated in terms of psi (pounds per square inch) or MPa (megapascals).
Yoke - The large ring surrounding the breech end of the barrel which provides a connection between the barrel and the recoil system. Shoulders on the gun prevent movement between the barrel and the yoke. In guns designed for case ammunition, the yoke is replaced by a housing.
/ Turret Definitions
AB - Armstrong Broadside. Inclined ramp type mounting used for British 6" (15.2 cm) guns of the 1880s.
ACAD - Automatique Contre-Avions Double. French for "Automatic AA Twin Mounting."
B - British designation for "Barbette" which at one time was used to denote a turret mounting.
Balanced Turret - Most turreted gun mountings of the 19th century were "unbalanced," that is, the center of rotation was not the same as the center of mass. Thus, when they were trained abeam, they induced a list on the ship, some so badly that the gun muzzles actually went into the water when the ship rolled in even moderate seas. By about the 1890s, "balanced" designs began to be introduced which did have the center of mass and rotation at the same or nearly the same point.
Barbette - The fixed armored ring around the trunk of the mounting. This usually extends from the gunhouse down to the armored or protective deck.
Base Ring - US designation. The entire gun mounting turns on a bearing race which for larger guns is big enough such that there is a space in the center where ammunition can be fed to the gun. All of the fully enclosed and most of the open mountings for the 5"/38 (12. 7 cm) were base ring types. Mountings for many smaller guns developed during World War II, such as the quad 40 mm Bofors, were base ring types as this design distributed the weight of the gun and mounting better than did a pedestal type.
BD - Between Decks. British designation for gun mountings that extended down into the ship while the guns themselves were above the deck. Before World War I, all British Capital ships had secondary guns that mounted directly on the weather deck with nothing piercing that deck down into the ship below. In the 1930s, new gun mounts were developed where the bulk of the mounting was below the weather deck. The term "BD" was used to distinguish this sort of mounting from the previous ones. See "UD" below.
Blast Bags, Bloomers or Gun Bucklers - Canvas, rubber or neoprene covers around the barrel of a gun where it enters the gun port. Gun ports by their nature represent holes in the glacis plate of a turret. When the guns are fired, these holes can allow overpressure or "blast" to enter the the turret, which can disrupt the operation of the turret and injure the gun crew. These holes may also permit water to enter the mounting. The use of blast bags over the gun ports provide some measure of protection from these hazards. Also see "Gun Port Shield" below.
Bogie or Shell Bogie - A wheeled device for moving projectiles around a gun mounting, usually moving on rails. A typical application was for moving projectiles from the fixed portion of the ship onto the rotating turret stalk.
BSG - Bettungschiess-Gerüst. German for "platform firing framework." These were mountings for large caliber guns used as coastal artillery and resembled a railway mounting without the rail bogies. They were supported on a concrete platform by a central pivot and ball race with a roller or bogie at the rear running on a circular arc.
CAD - Contre-Avions Double. French for "AA Twin Mounting."
CADAM - Cadence Améliorée. French for "improved firing." A program for French guns such as the 100 mm/55 Model 1968 intended to increase their firing rate.
CAQ - Contre-Avions Quadruple. French for "AA Quad Mounting."
Carriage - That part of the mounting which is carried in or upon the stand into which the trunnions seat. The carriage moves with the gun in train, but is fixed in elevation with the gun pivoting upon its trunnions for elevation changes.
CAS - Contre-Avions Simple. French for "AA Single Mounting."
Casemate - An armored enclosure containing a gun mounting. Unlike a turret, this enclosure does not rotate.
CP - Centre Pivot. British designation for a gun mounting that has a central axis for rotation on the horizontal axis. These mountings generally used a circular mounting plate bolted to the deck and supported by a below-deck, ring-shaped bulkhead known as the "gun support," which was used mainly for stowage. A lower roller path was machined on the base ring, with a similar upper roller path machined on the bottom of the turntable platform. Between the two machine paths were a ring of horizontal rollers which carried the weight of the mounting and gun. At the center of the turntable was a light cage which contained the vertical thrust rollers. This was the actual "center pivot" point. Electric cabling containing the fire control and illumination circuits ran through the center pivot. This cabling had enough slack to allow the mounting to train to its limit stops. In the USN, this type of mounting was called a "Pedestal" - see below.
Central Pivot - In the USN, this was a compact gun mounting with the center of rotation just below the gun barrel. Used a short "U" shaped bracket whose arms held the trunnions while the base of the "U" was mounted atop a small-diameter turntable.
Delay coil - When guns are mounted closely together in a turret, the shells may strike each other in flight or the individual airflow of one projectile may disrupt the adjacent projectiles, causing obvious problems. Starting in the 1920s, the USN alleviated this problem on their three-gun and triple mountings by installing a device which caused a brief delay, about 0.060 seconds, between when the outer guns fired and when the inner gun fired. Another method of reducing shell interference was used by the British in their "Town" and "Colony" six-inch (15.2 cm) cruisers of World War II, where the center gun of each triple turret was set back 30 inches (76.2 cm) from the outer two guns. This allowed all three guns to be fired simultaneously, at the cost of some complications in the design and construction of the gun house.
DCA - Défense Contre Avions. French for "Defense against aircraft" or anti-aircraft weapon.
Dopp MPL - Doppelt Mittel-Pivot-Lafette. German for "Twin central pivot mounting."
DrhL - Drehscheiben-Lafette. German for "turntable mounting." Generally used for turret mountings.
Drh Tr - Drehturm. Another German abbreviation for "Turret."
Elevation - The angle to which a gun can be moved on the vertical axis past the horizontal. For instance, a gun with a 90 degree elevation would be pointing straight up. A gun at 0 degree elevation would be pointing at the horizon. A gun with -10 degree elevation would be pointing below the horizon.
Gunhouse - The armored portion of the rotating structure extending above the barbette.
Gun Pit - A depression or opening on the gun deck into which the breech end of the weapon is lowered when the gun is raised to high elevations. This allows the trunnions of the gun to be mounted lower, thus lowering the overall height of the mounting while still allowing for high gun elevations.
Gun Port Shield - Curved armor plate attached to a gun barrel such that it seals the gun port in the glacis plate, regardless of the elevation of the gun. Gun ports are by their very nature weak points in the armor protection of a gun mounting or turret. Gun shields seal these openings and are intended to provide at least some measure of protection from shell splinters. In addition, many gun shields are designed so as to keep water and weather out of the interior of the mounting or turret. Some images of gun shields may be seen in these photographs of a USN 6"/47DP and a German 38 cm SK C/34.
Handling Room - Compartment just below the gun mounting where ammunition brought up from lower storage locations is loaded into hoists or scuttles for transferring up to the guns.
Kenyon Doors - British shell-handling device replacing shell bogies in some large-caliber mountings designs of the early 1900s. This was a tilting door which provided a flash-tight means of transferring shells between the shell room and the turret stalk, essentially similar to what the USN called a "scuttle" in their mountings. Named after the inventor, Thomas Kenyon. See this image of HIJMS Kongo from Vickers Photographic Archive for a photograph of a Kenyon Door as used on that ship.
Kst.Drh.L - Küsten-Drehscheiben-Lafette. German for "coastal turntable (turret) mounting."
1) For smaller weapons, this is a metal or plastic box which contains multiple rounds. This is attached to the weapon and supplies rounds into the firing chamber.
2) Compartment on a ship where ammunition is stored.
MPL - Mittel-Pivot-Lafette. German for "central pivot mounting."
P - Pedestal. British designation for a compact gun mounting with the center of rotation just below the gun barrel. A short "U" shaped bracket held the trunnions with the base of the "U" mounted atop a small-diameter turntable. Similar in design to a Central Pivot mounting as used in the USN.
Passing Box - A small container mounted between compartments with a flap or door on each end and used to provide a flash-tight method of moving powder bags from one compartment to another. Usually there is a mechanical connection such that only one flap can be open at a time.
Pedestal - In the USN, this is a mounting where the entire gun carriage turns on a roller-race. The carriage is usually slab-sided with the sides running all the way down to a platform whose bottom forms the top of the roller race.
Pintle - A flexible mounting where the gun is mounted at the top of a vertical post or rod.
Powder Room - A compartment where propellant charges are stored.
Projectile or Shell Flat - Usually refers to that portion of a magazine directly adjacent to the rotating structure of a turret. May also be used to refer to that portion of the rotating structure onto which projectiles are moved from their storage locations in the magazines.
Recoil Cylinders and Counter-Recoil Cylinders - Recoil Cylinders absorb the forces generated when the gun is fired. These normally consist of a hydraulic system using a piston whose rod is surrounded by a spiral spring. The cylinders are normally secured to a stationary part of the mount while the piston rods are secured to the gun. When the gun fires, the piston moves through the cylinder and the recoil force is checked by the friction of the hydraulic fluid as it passes from one side of the piston to other side via apertures not filled by the piston, such as grooves in the wall of the cylinder. By varying the width of these grooves, the amount of friction generated as the piston moves can be increased or decreased as desired. During the recoil stroke, the spiral spring is compressed. This compression force is used to push the gun back into battery. As the piston returns to its starting point, the hydraulic fluid again moves through the apertures, aiding in controlling the counter-recoil stroke. The counter-recoil stroke can be violent and in larger guns counter-recoil cylinders are used to better control the speed of the return stroke. A counter-recoil cylinder is essentially a recoil cylinder designed so as to produce the most friction as the gun returns to battery.
RP - Remote Power. World War II British designation for gun mounts equipped with RPC. Usually followed by a number which represented the type of power control. The RP10 series were hydraulically operated while the RP50 series were electrically operated.
RPC - Remote Power Control. Also known as "Auto Control" in the USN. This is a subject in itself. In its barest essentials, this means that the gun director and associated components automatically control the laying of the guns without manual intervention by the gun crew.
Scuttle - In the USN, a shell or powder handling device that allows a flash-tight transfer from one compartment to another, such as from a handling room up to a gunhouse. Commonly, this was a handle-operated rotating hollow drum with an opening on one side, with the opening accessible from only one compartment at a time. For example, a scuttle going between a handling room and a gunhouse would be loaded on the handling room side with a powder bag. Moving the handle rotated the opening in the drum over to the gunhouse on the other side, thus keeping the two compartments isolated from one another. At right is a picture of a scuttle used to transfer powder bags from a magazine onto a powder hoist on USS Iowa BB-61.
Sighting port - An opening for a gun-sight in the front of the gun-shield or turret glacis plate.
Sighting hood - Armored cover protecting the gun-sights protruding through the roof of a gunhouse or turret, although many of these were completely open to the front. On British capital ships of the World War I-era, superfiring turrets could not fire within 30 degrees of the axis because the blast effects would have penetrated into the lower turrets via the front openings in the sighting hoods. These hoods also represented a weak point in the protection of the turret and acted as shell traps. Several ships were damaged during World War I when German shells hit these ports, perhaps most notably on Q turret of HMS Tiger during the Battle of Jutland (Skagerrak) in 1915.
Shell Ring - On USN battleships and cruisers built in the 1930s-40s most of the projectiles were stored on fixed and rotating rings which were part of the upper and lower shell flats. Each storage flat was sub-divided into three concentric rings. The outer, or fixed ring, is attached to the stool and does not rotate. The center ring, or shell-handling platform, is part of the rotating structure including the gunhouse and contains the projectile hoists. It also mounts the parbuckling gear for moving the projectiles from their storage locations and onto the hoists. No projectiles are stored on this ring. The inner, or rotating ring, is a power driven platform resting on rollers which can be rotated in either direction and is supported by the rotating structure. The inner ring may be locked to the rotating structure (center ring) or to the stool as needed. Normally, the shells on this ring are the ones fed to the guns while those on the outer ring are moved only during non-firing periods.
Sleeving - In a multi-gun turret, if each individual gun can be raised independently of the other guns, then the guns are said to be individually sleeved. Guns that are not individually sleeved are said to share a "cradle" (UK usage) or a "slide" (USA usage). See "Turret Definitions," below.
Slide - The slide is that non-recoiling part of the mounting through which or upon which the gun or the gun slide cylinder moves in recoil and counter-recoil motions. The slide moves with the gun in train and elevation.
Stabilized mounting - A type of mounting which keeps the weapon at a constant point of aim regardless of the movement of the ship. May use as many as four different axes of motion; elevation, train, crosswise tilt (roll correction) and lateral tilt (pitch correction).
Stalk - That portion of the rotating structure of a turret that extends down into the ship.
Stand - That part of the mounting which is secured to the structure of the ship and in or upon which the carriage rests and is moved in train.
Stool - The fixed circular foundation bulkhead that supports the rotating elements of the gun house.
Superfiring - A gun mounted such that it can fire overtop another mounting without elevating its gun barrels from the horizontal is said to be superfiring. For example, on most ships with two forward turrets mounted on the centerline, the second turret from the bow is mounted higher than the first turret such that it may fire forward at almost any elevation. The second turret is thus superfiring.
Swashplate Engine - This was a type of steam-powered reciprocating engine employed by the British that used a circular plate (swashplate) in place of a crankshaft. These swashplate engines contained multiple pistons which were used to press down in sequence near the outer edge of the plate, making it wobble as it rotated about its center. Using a swashplate engine for turret training and elevation had the advantage of smoother incremental movements, as the jerking caused by the back and forth motion of the pistons was not directly coupled to the driveshaft.
Train - The angle to which a gun or turret can be rotated on the horizontal axis. For instance, a bow gun or turret pointing directly forward is said to be trained to 0 degrees. If it could rotate to point directly astern, then it would be trained to 180 degrees.
Transferable Mounting - A British term used in the early part of the twentieth century, meaning that the gun mounting was simply bolted to the deck with no other connections and so could be easily removed and used elsewhere. Replaced by "UD" (see below) in most official publications.
Turret - There is always a controversy about whether a particular rotating enclosed gun emplacement should be called a "Turret" or a "Mount." In the USN, the difference between a turret and a mount is that a "Turret" is built into the ship, has a stalk that extends well below the weather deck and includes a barbette, while a "Mount" is not part of the ship's structure and does not include a barbette. As a general rule, 5 inch (12.7 cm) and smaller guns are in "Mounts" while 6 inch (15.2 cm) and larger guns are in "Turrets." Other navies had similar distinctions.
Turret Definitions - In the USN, when multi-gun turrets are described as "two-gun" or "three-gun" it means that their guns are individually sleeved and that each gun can elevate independently of the others. When the mounting is described as "twin" or "triple" it means that all guns share a single slide or cradle and that individual guns can not elevate independently from the others. Other nations do not use these distinctions. On my weapon pages, the description for each weapon will indicate whether the mountings were individually sleeved or not.
UD - Upper Deck. British designation of the 1930s and 1940s referring to a gun-mounting that did not pierce the deck on which it was mounted. See "Transferable Mounting" and "BD," above.
VB and VCP - Vavasseur Barbette and Vavasseur Central Pivot Mountings. British gun mountings of the late 1800s that used inclined ramps to help absorb recoil forces. Named after Joseph Vavasseur (1834 - 1908) who at one point was connected with the Armstrong-Whitworth Co. and who is best remembered for inventing the process of using hydraulic pressure to fit copper driving bands onto projectiles in 1874.
Forward to "Gun Data" Part 3 - Miscellaneous
Back to the Naval Weapons Index Page
25 August 2008 - Benchmark
30 January 2009 - Updated British Nomenclature, added definition for Holmstrom breech mechanism
05 November 2009 - Added French mounting designations
17 September 2010 - Added more French designations
16 April 2013 - Minor changes to the Japanese and United States gun designation descriptions | <urn:uuid:326a1bd0-686b-4e7a-b49b-6e735bb00a4d> | CC-MAIN-2013-20 | http://www.navweaps.com/Weapons/Gun_Data.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.96149 | 16,772 | 3.6875 | 4 |
Liquid lakes buried thousands of meters below the Antarctic ice sheet are likely the home to unique habitats and creatures that thrive in them. Exploration of those lakes will therefore require extreme care and an international cooperative effort, according to a team of authors writing in the Dec. 6 issue of Nature.
The pressure exerted by the continent-wide ice sheet together with heat generated by the Earth from below and the enormous insulating properties of the overlying ice sheet, may mean that liquid water exists in many -- if not all -- of the lakes. That may mean that they harbor life, according to a team of authors, led by Martin Siegert of Bristol University.
Microbiologists funded by the National Science Foundation (NSF), working with ice samples gathered from deep beneath Russia's Vostok Station -- that is thought to be refrozen water from Lake Vostok itself -- have argued that microbes may survive in extreme cold and darkness under more than 4,000 meters of ice. John Priscu of Montana State University, one of those NSF-funded biologists, is a co-author of the paper.
Antarctica is home to more than 70 lakes that lie thousands of meters under the ice sheet. The lakes include one under the South Pole and another, Lake Vostok, deep in the Antarctic interior, that is comparable in size and depth to one of the North American Great Lakes.
Given the conditions in the lakes, the authors state, it is reasonable to believe "that subglacial lakes house a variety of microorganisms potentially unique to subglacial Antarctica and, if they are isolated hydrologically, unique to each lake."
In the Nature article, Priscu and his colleagues also argue that the sediments at the bottom of Lake Vostok, and in other lakes, may also sustain life.
They caution, though, that developing both the technology and the experimental protocols to explore those lakes without contaminating the waters or harming any microbial communities that may exist there will be an extremely complex undertaking that will require "significant multinational cooperation."
The United States Antarctic Program, which is managed by NSF and which coordinates almost all U.S. research in Antarctica, already has taken some non-invasive steps to explore Lake Vostok. During the 2000-2001 research season, researchers from the University of Texas at Austin conducted a detailed aerogeophysical survey of the lake, including radar sounding, laser altimetry, magnetics, and gravity. Their maps are being analyzed by researchers at Lamont Doherty Earth Observatory at Columbia University. The goal of the work is to more thoroughly understand its physical and geographical boundaries.
In 1999, two NSF-funded teams, one headed by Priscu and another headed by David Karl of the University of Hawaii, published papers in Science describing evidence that viable microbes lived in the "accreted," or melted and refrozen ice from Lake Vostok.
Priscu and his co-authors write in the Nature article that these investigations into the nature of Lake Vostok "have helped to define the next generation of research objectives, and it is likely that several exciting bio-geochemical-physical systems will be documented during the next decade."
Recognizing the scientific and technological challenges and opportunities of such an undertaking, NSF's Office of Polar Programs has established an NSF committee to study the possible scientific exploration of the lakes.
Karl Erb, who heads the U.S. Antarctic Program, cautioned committee members that future workshops to discuss whether and how to proceed with scientific exploration will need to explore how advanced technologies, including technologies that may as yet not be developed, can enable scientists to achieve their research goals. He noted that the workshops will "bring out the likely interplay between science goals and technology requirements: The goals should define the requirements but the state of the technology may proscribe the goals."
He also adds that any scientific exploration of subglacial lakes, including Lake Vostok, should include international and interagency participation.
Read about the Vostok research conducted by Priscu and by Karl at: http://www.nsf.gov/od/lpa/news/press/99/pr9972.htm
Read a report on an NSF-funded 1998 workshop, "Lake Vostok: A Curiosity or a Focus for Interdisciplinary Study?" at: http://www.ldeo.columbia.edu/vostok/
NSF's Office of Polar Programs has established a committee to study the possible scientific exploration of subglacial Antarctic lakes. Read the committee's charge at: http://www.nsf.gov/od/opp/antarct/subglclk.htm
The international Scientific Committee on Antarctic Research maintains a site on the exploration of subglacial lakes at: http://salegos-scar.montana.edu/
Editors: For available photography and b-roll, call Dena Headlee, (703) [email protected] | <urn:uuid:922314b1-c91c-4f9d-9c99-da95962471e0> | CC-MAIN-2013-20 | http://www.nsf.gov/od/lpa/news/press/01/pr0194.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.924305 | 1,029 | 4.0625 | 4 |
Most people are familiar with the problem of lead poisoning in children. But, what many donít know is that adults are also affected. While in children lead exposure typically occurs in or around the home, for adults itís primarily a workplace problem.
Workers in over 120 different industries are exposed to lead. Construction workers might come across lead when performing demolition; painters may come into contact with it when sanding or scraping old lead-based paint; radiator repair workers can be exposed to lead when welding or soldering parts.
Many of these workers donít recognize that theyíre handling materials that contain lead. Even those that do frequently donít understand why it presents a hazard.
Lead can enter the body in one of two ways: small lead particles can be inhaled directly or they can settle on things like food and drinks and subsequently be ingested. (Most lead cannot enter the body through the skin.) Lead particles are generated in a variety of different ways. Melting or soldering a lead-containing alloy, for example, creates lead fumes; cutting, grinding, or polishing a material that contains lead generates lead dust; and spraying a lead-containing paint or glaze forms a lead mist.
After entering the body, lead circulates in the blood and is stored in the bones. Over time, lead levels build up in the body and cause a variety of health problems. Leadís effect on the nervous system can result in headaches, irritability, difficulty sleeping, poor concentration, and memory loss; its effects on the gastrointestinal system include nausea, constipation, diarrhea, lack of appetite, and abdominal pain. Damage to the bone marrow caused by lead can result in a reduced red blood cell count called anemia. Severe lead poisoning can be fatal.
But exposure to leadóparticularly at low levelsódoesnít always cause symptoms. Even when symptoms are present, theyíre often subtle and may mimic other illnesses. This can make lead poisoning difficult to diagnose. In fact, serious and sometimes irreversible health problems occur before lead poisoning is detected.
Thatís why itís important to be regularly tested for lead exposure if you work with it. A blood test can be used to measure the amount of lead in your blood. If your blood lead level is found to be high, your employer must remove you from the area or task where your exposure to lead is occurring. Your body will then naturally eliminate lead over time and your blood lead level will gradually decline. In cases of severe poisoning, medications may be necessary to treat the poisoning.
California state law requires that employers take precautions to protect workers from lead exposure. The General Industry Lead Advisor
enforced by the California Occupational Safety and Health Administration (Cal/OSHA) requires that employers:
Train employees how to work with lead safely. Health and safety training on the hazards of lead must be conducted annually.
Provide medical monitoring. Medical examinations and blood lead testing must be made available to employees exposed to air lead levels at or above an Ďaction levelí established by Cal/OSHA. (The action level is 30 micrograms of lead per cubic meter of air averaged over an 8-hour period.)
When air lead levels exceed the permissible exposure level, the employer must also:
Furnish protective clothing and equipment. Appropriate protective work clothing and equipment must be provided to employees.
Provide a change room and shower facilities. Separate storage facilities for work clothing and equipment and for street clothing must be available to prevent cross contamination with lead.
Provide a clean lunchroom. Eating, drinking, and smoking in areas where air lead levels are elevated must be prohibited.
Unfortunately, not all employers abide by these regulations. For example, studies have found that only a small percentage of employers in lead industries provide routine blood lead testing for lead-exposed employees.
If you work with lead (or believe you might) and feel that your employer is not taking the appropriate precautions to protect you, contact Cal/OSHA. Cal/OSHA will not tell your employer who made the call. For help finding the office nearest you, contact the Cal/OSHA Worker Hotline
at (866) 924-9757.
Occupational Lead Poisoning Prevention Program (California Department of Public Health)
Safety and Health Topics: Lead (U.S. Occupational Safety & Health Administration)
Workplace Safety and Health Topics- Lead (Centers for Disease Control and Prevention) | <urn:uuid:0c837586-f2eb-4cd8-a77b-e7c5095989c7> | CC-MAIN-2013-20 | http://www.publichealth.lacounty.gov/eh/TEA/ToxicEpi/leadintheworkplace.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.935199 | 911 | 3.5 | 4 |
Questions about Head Lice:
1. Where do head lice come from?
Head lice are human parasites and do not come from the air or ground. In fact, head lice have probably been here since the beginning of time. Head lice and nits that have dried up have been found on the hair and scalps of Egyptian mummies.
2. How are head lice spread?
Head lice can be acquired when there is direct contact of the head or hair of someone infested with head lice. Lice can also be spread through the sharing of hats, brushes, helmets, hair accessories and other items. There is also the chance of spreading head lice through pillowslips.
3. How widespread are head lice?
The Centers for Disease Control does not track the number of head lice cases, because it’s not considered a disease. This makes it difficult to track head lice cases; however, schools and manufacturers of lice products estimate head lice cases at 12-25 million infestations a year in the United States. Most children infested with head lice are under twelve years of age.
4. Do head lice transmit or carry any disease?
While many have thought head lice to be only a nuisance, recent scientific study shows that head lice are the same species as body louse which has long been associated with diseases such as typhus and relapsing fever. Disease transmission through head louse should not be underestimated.
5. Can our family pet get head lice?
People cannot catch head lice from pets. They are human parasites and require human blood to survive.
6. How can I verify successful treatment of head lice?
You must first define treatment. Someone can be treated for head lice and still be infested. The ultimate determination that someone is no longer infested can only be accomplished with a thorough manual screening to confirm that all lice and nits are dead. | <urn:uuid:79de3cc1-d52f-409b-8c21-769449ddc0f3> | CC-MAIN-2013-20 | http://www.quitnits.us/category/about-head-lice/faqs-common-myths-facts/head-lice-faqs/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.959602 | 410 | 3.765625 | 4 |
Jan. 12, 2010 Scientists in Vienna have developed a new technique for producing vaccines for H1N1 -- so-called swine flu -- based on insect cells. The research, published in the Biotechnology Journal, reveals how influenza vaccines can be produced faster than through the traditional method of egg-based production, revealing a new strategy for the fight against influenza pandemics.
"Recent outbreaks of influenza highlight the importance of a rapid and sufficient vaccine supply for pandemic and inter pandemic strains," said co-author Florian Krammer from the University of Natural Resources and Applied Life Science in Vienna. "However, classical manufacturing methods for vaccines fail to satisfy this demand."
Traditional influenza vaccines, which are produced in embryonated chicken eggs, can be manufactured in the quantities needed for seasonal strains of influenza. Yet because of limited egg supply this method may be insufficient in a pandemic scenario, such as the current H1N1 'swine flu' pandemic.
The team's new method turns to insect cell based technology to create recombinant influenza virus-like particles (VLPs), which resemble virus particles but lack the viral nucleic acid, so they are not infectious.
The Austrian team took just ten weeks to produce swine-origin pandemic H1N1 influenza VLPs for immunological study in mice. This shows that production of a mock-up vaccine is feasible in this time range, outcompeting conventional production methods which take months.
Using insect cells also bypasses the disadvantages of egg-based production, such as limited production capacity, allergic reactions to egg proteins and biosafety issues.
"Our work demonstrates that recombinant influenza virus-like particles are a very fast, safe and efficient alternative to conventional influenza vaccines and represents a significant new approach for newly emerging influenza strains like swine-origin H1N1 or H5N1," concluded Krammer.
"Virus-like particles will be one solution to tackle the biological variability of influenza pandemics," said journal editor Professor Alois Jungbauer. "Mutated strains can be quickly engineered. So in this respect the teams' work is an extremely valuable contribution to modern vaccine production."
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Note: If no author is given, the source is cited instead. | <urn:uuid:b3f88112-ccb0-409b-a91e-7f49ac32a2f3> | CC-MAIN-2013-20 | http://www.sciencedaily.com/releases/2010/01/100104191928.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.918555 | 493 | 3.75 | 4 |
Early American song began with the first settlers and continued through the Age of Reconstruction. Songs written during these years were inspired by political events and transcended their era to become the soundtrack of American history.
Traditionally, music had been limited to the region in which it developed. Until 1825, only a few popular songs had achieved permanence in the fabric of American popular music. The primary reason for this was a lack of distribution means--no radio or phonograph, an immobile population, and no machinery for plugging or producing a written reference for the song. With its creation in the mid-1800s, sheet music provided songs with an outlet for distribution and merchandising and introduced Americans to different sounds previously isolated to their regions.
In Colonial America, inspirations for song depended heavily on English, Irish and Scottish ballads as well as the hymnals of the religious society. Americans of the Colonial period sang of events and people of current interest. They introduced the musical style that would later adapt itself to documenting patriotism, politics and heroism.
With the Declaration of Independence, patriotic marches were introduced, and these dominated the American song until the late 1700s.) dominated the American song until the late 1700s. Despite this dominance, other musical styles eventually began to surface along with the diversifying American culture. Negro songs were introduced in the late 1700s, and popular music adopted simple melody--a balance between text and tune and a sameness of rhythm.
The period before the Civil War is widely recognized as the period of the torch song and minstrelsy. Minstrel shows showcased songs and acknowledged songwriters individually for the first time, and as the shows traveled, more American regions were exposed to the songs. By the late 1850s, printed sheet music was available and transformed the way Americans were exposed to music. Fans were able to play and hear their favorite songs anywhere--not just at a minstrel show or concert or by word of mouth, but right in their homes.
With the start of the Civil War, American songwriting once again voiced patriotism and sentiment. During the Age of Reconstruction, American music reverted back to the old themes of sentimentality, comedy and religion. During that time, the epicenter of the music publishing and songwriting business was being established in New York. All regional melodies and genres were converging and musical influences previously segregated regionally, were combining to create the American popular song.
America the Beautiful first appeared in print in the weekly journal The Congregationalist, on July 4, 1895. The lyrics were written while on an 1893 summer lecture series at Colorado College in Colorado Springs.
Looking at the view of the Rockies from Pikes Peak, its author, Katharine Lee…
AMERICA THE BEAUTIFUL | <urn:uuid:c2d5efbf-540f-4e41-89d4-1623d037d63d> | CC-MAIN-2013-20 | http://www.songwritershalloffame.org/exhibits/eras/C1001 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.978013 | 564 | 4.25 | 4 |
The rose diagram shows how commonly and how strongly the wind blows from different directions through a typical northern hemisphere summer. The longest spokes point in the directions the wind most commonly blows from and the shade of blue indicates the strength, with the strongest winds shown by dark blue. It is based on 5065 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to Fox Hill Point, located 23 km away (14 miles). There are too few recording stations world wide to use actual wind data. Without question some coastal places have very localized wind effects that would not be predicted by NWW3.
According to the model, the most common wind at Fox Hill Point blows from the SE. If the rose graph shows a fairly circular pattern, it means there is no strong bias in wind direction at Fox Hill Point. Converseley, dominant spokes illustrate favoured directions, and the more dark blue, the stronger the wind. Spokes point in the direction the wind blows from. Over an average northern hemisphere summer, the model suggests that winds are light enough for the sea to be glassy (the lightest shade of blue) about 13% of the time (12 days each northern hemisphere summer) and blows offshore 41% of the time (29 days in an average northern hemisphere summer). In a typical northern hemisphere summer winds stronger than >40kph (25mph) are expected on 2 days at Fox Hill Point
IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean. | <urn:uuid:4fd58ff5-1837-4403-bfa4-a6f72a9cee57> | CC-MAIN-2013-20 | http://www.surf-forecast.com/charts/Fox-Hill-Point/wind/statistics/summer | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.922792 | 348 | 3.625 | 4 |
How to Read Violin Notes for Beginners
4 Simple Steps
With many people looking at saving money when it comes to learning new things, it comes to a number learning how to read violin notes for beginners. This is the easiest part of learning how to play the violin and can be done in a few easy steps.
There are teachers that can help you learn quickly, here is a world renowned concet violinist that can teach you from start to finish from the comfort of your own home, click here to find out more: Study with Eric Lewis.
Over years, many people have learned how to play music by listening and mimicking. This is known as playing by ear and while it is a great skill, it does not get many people very far. It is very important to learn how to read violin notes for beginners and follow the few simple steps listed so that you can become the next famous violinist.
You need to work out which is the treble clef, which is the one that the right hand plays on piano music. It has a very similar looking & symbol, always placed at the start of each line. If you find music with a backwards looking C, then you are looking at the bass clef, which is the wrong one entirely.
You need to understand what each of the notes that sit on the five lines of the stave. These are E, G, B, D, F and you can easily remembered with the phrase “Every Good Boy Does Fine”. Eventually, these notes will come second hand and you will not need to remember the phrase to know what notes you are playing.
You also need to know what the notes in the spaces of the stave lines mean. These are F, A, C, E, which spells out a word all by itself. These are generally easier to remember that those that are on the lines already.
There are notes that can sit above or below the stave lines and you will generally see them with lines drawn through them. All the notes are labeled A-G and are then repeated so it is easy to tell which notes, as long as you know the basic ones.
When you learn how to read violin notes for beginners, it may seem difficult at first and you may benefit from writing the letter names above them so that you do not need to think too much. However, eventually they will all become second nature and you will be able to tell a note the minute that you see it. The hardest part of learning to play the violin is actually learning to play it and getting the technique right.
I’ve haven’t even scratched the surface but here is someone who will take you by the hand and help you learn from A-Z in the privacy and comfort of your own home, click here to find out more: Study with Eric Lewis.
Article Source: http://EzineArticles.com/?expert=Jennifer_Hinds | <urn:uuid:7d3333b0-be87-40f6-b624-fb73946af436> | CC-MAIN-2013-20 | http://www.violinnotes.org/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.977047 | 604 | 3.53125 | 4 |
Planetary Oceanography: Enceladus
|An image taken by the Cassini spacecraft of Saturn's moon Enceladus backlit by the sun. Note the the fountain-like sprays of material being ejected from the south polar region (bottom left). (NASA/JPL/Space Science Institute)|
|Temperature map of Enceladus retrieved by the Cassini spacecraft. Note the intense hot spot at the south pole (bottom). Higher resolution images of this area show even hotter temperatures, associated with young cracks in the crust.|
|The overall shape of Enceladus is unusual as well. (The deviations are highly exaggerated in this picture.) The distance from pole to pole (c) is somewhat smaller than one would expect, if the planet were composed of differentiated rock (tan) and ice (white) layers. We feel this can be explained by the presence of a molten "sea" (blue) beneath the south pole. The south polar surface would be depressed as the ice changed to liquid and contracted.|
Geoffrey Collins (Wheaton College)
When Cassini, NASA?s ongoing mission to Saturn, turned its cameras to the small icy moon Enceladus, the results stunned the planetary science community (Porco et al, 2006). They showed a dramatic geyser-like plume of gas and ice being ejected from the south polar zone, along with an enigmatic hot spot and a violently cracked and disrupted south polar surface. The overall shape of the planet is also somehow affected: it is more oblate than would be expected from its size, orbital position, and likely internal structure.
We believe that the formation of a south polar ?sea? of liquid water beneath the ice crust can explain all these observations. Using the same sorts of models previously applied to Europa and Snowball Earth, we demonstrate (Goodman and Collins, 2006b) that melt-contraction of a thick ice layer would distort the planetary figure, producing the observed oblate shape, while also producing the observed surface terrain disruption and thermal output.
And yet, this is only the beginning. The Cassini spacecraft has only just begun to explore the Saturnian system, and continually poses new puzzles for interested fluid dynamicists, from the sea and geysers of Enceladus to the hydrocarbon rains and rivers of the giant moon Titan.
Porco, C.C., and 24 colleagues, 2006. Cassini observes the active south pole of
Enceladus. Science 311, 1393-1401.
Goodman, J. C. and G. C. Collins, 2006b. Enceladus?s South Polar Sea. Submitted to Icarus. | <urn:uuid:cb0ff5d8-50ff-4099-8175-bfdcdba3b681> | CC-MAIN-2013-20 | http://www.whoi.edu/hpb/viewPage.do?id=6997&cl=3 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.908277 | 555 | 3.71875 | 4 |
Intensive Care Phase
The Burn ICU manages patients after burn injuries. Visiting hours are flexible in this Unit, depending on the patient's condition, how busy the unit is at the time, and the needs of the family.
Medical Treatment in the ICU
Burn patients are monitored closely in the ICU. Patients may be attached to equipment that monitors their heart rate, blood pressure, oxygenation, and the pressure inside the head (intracranial pressure). Patients may have several tubes, wires, and intravenous lines to help the staff assess and treat them. A patient's body may appear swollen due to all of the fluids required for treatment, but this is normal.
The staff may give oxygen via a face mask, nasal prongs, or breathing tube. If a breathing tube is in place, it will be attached to a respirator to help the patient breathe. Patients cannot speak while the tube is in place. The staff closely follows blood gases and chest x-rays to help decide when the breathing tube can be removed. Patients are gradually removed from the ventilator so that they can breathe on their own.
A number of intravenous lines may be placed so that the patient can receive fluids, blood products, and medications, if necessary. Blood transfusions may be needed if the patient shows signs of bleeding. Drugs may also be given to keep the patient's heart rate and blood pressure normal. A patient usually needs to stay in the ICU until the heart rate, blood pressure, and blood tests are stable.
A patient may also have a tube in the nose or mouth that extends down into the stomach. Burns and other medical conditions often cause the stomach not to work properly for several days. The tube keeps the stomach empty until it starts working normally. If surgery has been performed on the abdomen, the patient may also have drains in place. In general, these drains will come out when they stop draining fluid.
Nutritional needs are addressed early in a patient's hospitalization. Feedings may be given through a tube in the mouth or nose until the patient is ready to start eating. Sometimes, however, a person's stomach may not be able to digest food due to the injuries. If this happens, the patient may receive what is referred to as "TPN" for nutrition through an intravenous line.
Patients in the ICU are frequently given medicines to help control pain. These medicines often make patients groggy and confused. Many do not remember their stay in the ICU once they recover and move into a general care burn bed on Bigelow 13.
The burn team visits patients each day between 6:00 and 7:30 am (and as needed) to review progress and plan the daily care. Each day, the team will evaluate each ICU patient and assess whether they’re ready to transition out of ICU care and into a general care burn bed. | <urn:uuid:b9682f2b-70bd-4ae7-ad1c-ba8505639964> | CC-MAIN-2013-20 | http://www2.massgeneral.org/burns/patients/intensive.care.phase.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704218408/warc/CC-MAIN-20130516113658-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.941942 | 592 | 3.71875 | 4 |
A fluorescent lightbulb generates about four times as much light per watt as a standard incandescent lightbulb. This makes fluorescents by far the most economical light source for the home today.
Once used only in kitchens and workplaces because of their harsh light, today's fluorescents produce light in a wide range of whites and colors. Bulbs come in many shapes and sizes, with socket pins to fit fluorescent fixtures or screw-type bases to replace incandescent bulbs.
Because of the power surge needed to start a fluorescent, frequent turning on and off of a fixture wastes power and shortens tube life. When leaving a room for only a short time, it is usually best to leave the light on.
The ordinary fluorescent fixture consists of a bulb and a ballast in a metal channel. The bulb is an airtight glass tube with cathodes--metal conductors of electricity--at both ends. It holds argon gas and mercury vapor, and the interior is coated with phosphor, a substance that can be electrically stimulated to emit light.
The ballast is a transformer that boosts 120-volt household current to the 300-plus volts needed to light the bulb when you turn the fixture on, then reduces voltage to the level needed to keep the bulb lit. When the switch is turned on, power flows between the cathodes, heating the gases and phosphor so they glow, or "fluoresce."
Older fixtures (and many small modern ones) have a small, separate starter built into them to preheat the gases.
Another fluorescent fixture is an instant-start style preferred by industrial users for its low maintenance. However, bulb life is only about 9,000 hours.
Most homes have rapid-start fixtures whose bulbs may last 20,000 hours. As the names imply, the instant-start fixture goes on immediately, while the rapid-start fixture flickers for two or three seconds before lighting completely. The older starter types take 15 to 20 seconds to light properly. Fluorescent bulbs give off less light at temperatures below 50 degrees. If the fixture is to be in an unheated garage or basement, install a cold-rated ballast.
The light output of fluorescent bulbs decreases with time.
Blackening at the ends of a tube means that it's worn out; replace it. If only one end of the tube is discolored, remove it, turn it over and reinstall it. Replace an old or burned-out bulb with a new one of the same type (double-pin or single-pin), length and wattage.
Double-pin rapid-start and older starter-type bulbs are interchangeable. Instant-start bulbs have single pins. If the bulb is missing from a fixture, check the ballast to find the right size.
Dispose of old bulbs carefully. The gases and phosphor aren't poisonous, but the bulb may explode if broken, sending glass fragments flying. Never throw a fluorescent bulb into a fire or incinerator.
Fixing straight-tube fluorescents
Fluorescent problems are rare and usually easy to fix. A starter is inexpensive to replace, but a ballast costs so much that when one fails, it's often more economical to buy a new fixture.
If a fluorescent lamp fails to light, check for a blown fuse or tripped circuit breaker in the main panel. If the tube still doesn't light, or if it flickers or blinks, turn off power to the fixture and twist the tube slightly back and forth to make sure it's firmly seated in the sockets.
If that doesn't work, give the tube a quarter turn toward you and pull it out, handling it carefully. Use long-nose pliers to straighten a bent tube pin. Spray the socket contacts and the pins with electric contact cleaner. Clean a dirty tube with a damp cloth; let it dry before reinstalling it. Tighten the socket screws; replace broken sockets.
To reinstall the tube, line up the pins with the socket slots, push the tube in and give it a quarter turn. Still no light? Install a new tube of the same wattage and type. A new tube may flicker for an hour or two at first. If flickering lasts longer or if the new tube doesn't light, replace the starter with a new one of the same wattage. Rapid- and instant-start fixtures don't have starters. | <urn:uuid:1fb89e59-0663-426a-b23b-3300a728f4a8> | CC-MAIN-2013-20 | http://articles.latimes.com/1997-03-22/home/hm-40780_1_fluorescent-fixture | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.910942 | 906 | 3.515625 | 4 |
October 10, 2012
Few things in paleontology generate as much speculation, and ridicule, as the arms of Tyrannosaurus rex. In a culture where “bigger” is confused with “better,” we can’t seem to get our heads around why such a large predator would have such small forelimbs. Most puzzling of all is that the dinosaur’s arms were not vestigial–they were muscular appendages that must have had some function. But what?
Our understanding of tyrannosaur arms is constrained by what we think that dinosaurs were capable of. The trick is parsing the difference between what T. rex could do and what it actually did. Even though it appears that the forelimbs of the tyrant dinosaurs became smaller as they developed heavier heads capable of crushing bites, this doesn’t necessarily tell us what T. rex and kin used their arms for, if anything.
When I was a kid, though, there was one possibility that popped up in the dinosauriana I loved to browse. As seen in the clip above, from the documentary Dinosaur!, some paleontologists thought that tyrannosaurs could have used their arms to raise themselves off the ground after resting or–as in this case–embarrassingly being knocked to the ground by an Edmontosaurus. For a creature with such tiny arms, researchers speculated, T. rex might have been surprisingly skilled at push-ups.
The idea goes back to Barney Newman, a paleontologist who worked at what is now London’s Natural History Museum. In 1970, after overseeing a reconstruction of T. rex at the museum, Newman wrote a short paper on the posture of the famous dinosaur. Not only did the tyrant have a more bird-like posture than previously thought, Newman wrote, but he finally found a use for those short arms. The heavy construction of the dinosaur’s arms and shoulder girdle showed that the chest and arms of T. rex were surprisingly beefy, and, in Newman’s view, all that muscle and bone acted as a set of brakes.
At rest, Newman suspected, T. rex sat in a kind of crouch with its legs “folded under the body in much the same way as a hen’s,” lower jaw on the ground and palms flat. When the dinosaur stood up, Newman suggested, “The role of the fore-limbs was that of a brake holding the body, so that the force exerted by the extension of the hind-limbs was transmitted to the pelvic region, thus pushing it upwards.”
Newman didn’t say that T. rex pushed the fore-part of its body off the ground. Artists and filmmakers confused what Newman had hypothesized–that the seemingly overbuilt arms of the dinosaur acted as stabilizers as T. rex extended its legs to stand. But, the T. rex stretch meme aside, there’s no reason to think that the theropod actually behaved as Newman supposed.
In Newman’s reconstruction, the wrists of T. rex make the dinosaur’s hands face palms-down. That would have given the tyrant some grip as it stood. But we know that theropod wrists didn’t articulate this way. As paleontologists frequently point out, theropods were clappers, not slappers–their palms faced inwards, towards each other, and flexed more like bird wrists. A wonderful sitting trace of an Early Jurassic theropod confirms this position, as do other smaller theropod skeletons preserved in the act of nesting or resting. In order to achieve a palms-down grip on the ground, T. rex would have had to swing its arms far out to the sides so that the dinosaur’s hands came into the right position.
Dinosaur traces and roosting skeletons also tell us something else. Newman was right that T. rex, like other theropods, probably sat in a very bird-like position. But, like both avian and other non-avian theropods, there’s no indication that tyrannosaurs needed extra stabilization to stand up. The thick heads and heavy tails of tyrannosaurs were counterbalanced over their hips, and they probably sat down and stood up in the typical theropod manner without the need for brakes. Newman’s hypothesis was a clever one for a long-running paleo problem, but what T. rex used those small, strong arms for remains as contentious as ever.
Newman, B. 1970. Stance and gait in the flesh-eating dinosaur Tyrannosaurus. Biological Journal of the Linnean Society, 2. 119-123
Sign up for our free email newsletter and receive the best stories from Smithsonian.com each week. | <urn:uuid:da3b98d4-0ae1-40ba-ac9f-82cf5501a1d1> | CC-MAIN-2013-20 | http://blogs.smithsonianmag.com/dinosaur/2012/10/doing-the-t-rex-stretch/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.967521 | 998 | 3.8125 | 4 |
Third Battle of Ypres
For 18 months the British prepared 21 huge land mines underneath the German lines along the Messines Ridge southeast of Ypres, Belgium, a location that had already seen major battles in 1914 and 1915. The British detonated these massive mines in early June 1917, though only 19 exploded. One exploded in the early 1950s, and one remains unexploded under the ridge (no one knows its exact location). This was to enable the British to gain the heights. The battle began on July 31st, when the British forces charged the German positions.
At first the strategy worked, as the Germans were confused and disorganised by the preliminary bombardment. But the British did not pursue the Germans as quickly as they should have. Rain began to drench the area in one of the wettest summer and autumn period in years, in a low-lying area where years of fighting had destroyed the land drainage system. Soon the Allied forces became bogged down in the mud, and the British only managed to gain a few miles during the following months, finally gaining the ridge of Passchendaele before winter forced an end to the fighting. For the loss of several hundreds of thousands of men , the British achievement was to gain the heights around the Ypres Salient, which meant the area became relatively safer - at least for a few short months until the German Spring Offensive of March, 1918. | <urn:uuid:429a62bd-5de6-41fe-8de5-abb75703b74c> | CC-MAIN-2013-20 | http://conservapedia.com/Third_Battle_of_Ypres | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.980537 | 284 | 3.765625 | 4 |
|Syria Table of Contents
SYRIAN SOCIETY IS a mosaic of social groups of various sizes that lacks both a consistent stratification system linking all together and a set of shared values and loyalties binding the population into one nation. Distinctions of language, region, religion, ethnicity, and way of life cut across the society, producing a large number of separate communities, each marked by strong internal loyalty and solidarity. Although nearly twothirds of the people are Arabic-speaking Sunni Muslims, they do not constitute a unitary social force because of the strongly felt differences among beduin, villager, and urban dweller. A perceptive observer has spoken of the "empty center" of Syrian society, a society lacking an influential group embodying a national consensus.
The ethnic and religious minorities, none of which amounts to more than 15 percent of the population, nevertheless form geographically compact and psychologically significant blocs that function as distinct social spheres and dominate specific regions of the country. Because the religious groups in each locality function as largely independent social universes, a "minority mentality," characterized by suspicion toward those of different groups, is widespread among both minority group members and those of the majority group living in minority-dominated areas where they are therefore outnumbered. Psychologically and politically, religious distinctions are by far the most significant ones. In all groups, loyalty to one's fellow members, rather than to a larger Syrian nation, is a paramount value.
The religious communities are more than groups of coworshipers; they are largely self-contained social systems that regulate much of the daily life of their members and receive their primary loyalty. The independence of the religious communities is a distinctly divisive force in society. Although Islam provides the central symbolic and cultural orientation for about 85 percent of Syrians, minority communities, most with a long history in the region, maintain cultural and religious patterns outside the Muslim consensus.
The religions, sects, and denominations differ widely in formal doctrine and belief. Nevertheless, there exists in Syria a stratum of folk belief and practice common to rural and uneducated persons of many religions. Members of various groups hold certain common beliefs in saints and spirits and observe related practices, such as exorcism and visitation of shrines, regardless of the disapproval of the orthodox religious authorities.
In addition to linguistic and religious dissimilarities, three forms of traditional social and ecological organization further divide the society. Most Syrians, including many members of religious and ethnic minorities, inhabit rural villages and earn their living as subsistence farmers. A dwindling number live the admired nomadic life of the beduin, or tribesman. The remainder, including a substantial number of recent migrants from the countryside, live in cities and towns, many of which date from ancient times. Each of these three represents a distinct, usually hereditary, way of life, followed by particular social groups and separated from the others by such social barriers as marriage restrictions, education, and occupation.
The ascent to power of minority groups and their implementation of Baathist policies of secularism and socialism, has left most non-Muslims financially better off than the average Syrian, putting them in an anomalous position. On the one hand, many have reasserted their solidarity with Syria's opposition to Israel, the West, alleged imperialism, and capitalism. On the other hand, some observers have noted an exodus of numerous urban businessmen, professionals, and managers, particularly Christians and non-Arabs. In response, during the mid- and late-1970s, the government encouraged the return of these émigrés and attempted to develop a climate more favorable to them.
Successive Syrian regimes have attempted to consolidate a Syrian national identity by eliminating the centrifugal effects of sectarianism. Despite these efforts, Syria's postindependence history is replete with conflict between minority groups and the central government.
In part this conflict can be attributed to the French mandatory administration, from which Syria inherited a confessional system of parliamentary representation similar to that of Lebanon, in which specific seats were allocated to Christians, Kurds, Druzes, Alawis, Circassians, Turkomans, and Jews. These ethnic and religious groups were guaranteed 35 of parliament's 142 seats. Minority groups also protested what they believed to be infringement on their political rights, and in 1950 successfully blocked efforts by the Sunni Muslim president to declare Islam the official state religion. A 1953 bill finally abolished the communal system of parliamentary representation;subsequent legislation eliminated separate jurisdictional rights in matters of personal and legal status which the French had granted certain minority groups.
The struggle to balance minority rights and Sunni Islamic majority representation remains a paramount theme in Syrian domestic affairs. In 1987, the Syrian government was dominated by President Hafiz al Assad's Alawi minority. The secular socialism of the ruling Baath (Arab Socialist Resurrection) Party deemphasized Islam as a component of Syrian and Arab nationalism. However, Baath ideology prescribed that non-Muslims respect Islam as their "national culture."
In 1986 educational and cultural institutions remained under close governmental supervision. Such institutions were designed to further government objectives by raising the general level of education and literacy, strengthening awareness of Arab cultural achievements, building public support for official policies resting on the principles of the ruling Baath Party and seeking to foster a sense of Syrian national unity. Public bodies serving these objectives multiplied during the late 1960s and by the mid1980s included the ministries of education, higher education, information, and national guidance and culture. Their activities were complemented by several directorates, authorities, and planning boards. In the consolidated budget for fiscal year ( FY) 1985, nearly LS (Syrian pound) 3.43 billion, or 14.5 percent of the government's expenditure, were earmarked for education of minorities. Despite the educational system's failure to achieve the government's goals, education remained an important channel of upward mobility for minorities.
Source: U.S. Library of Congress | <urn:uuid:5a4860dd-0b0d-4dc5-be98-e0fb3c88de6d> | CC-MAIN-2013-20 | http://countrystudies.us/syria/20.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.954201 | 1,192 | 3.5625 | 4 |
The currency sign (¤) is a character used to denote an unspecified currency. It is often used in place of a symbol that is not present in the font in use; for example, in place of the Colón (₡). It can be described as a circle the size of a lowercase character with four short radiating arms at 45° (NE), 135° (SE), 225°, (SW) and 315° (NW). It is slightly raised above the baseline. It is represented in Unicode as U+00A4 ¤ currency sign (HTML:
The currency sign was once a part of the Mac OS Roman character set, but Apple changed the symbol at that code point to the euro sign (€) in Mac OS 8.5. In non-Unicode Windows character sets, the euro sign was introduced as a new code point. In the Unicode character set, each of the two symbols has its own unique code point across all platforms.
The symbol was first encoded for computers in 1972, as a replacement for the dollar sign in national variants (ISO 646) of ASCII and the International Reference Variant. It was proposed by Italy to allow an alternative to encoding the dollar sign. When ISO 8859 was standardized, it was placed at 0xA4 in the Latin, Arabic and Hebrew character sets. There was not room for it in the Cyrillic set, and it was not included in all later added Latin sets. In particular, Latin 9 replaces it with the euro sign. In Soviet computer systems (usually using some variant of KOI8-R character set) this symbol was placed at the code point used by the dollar sign in ASCII.
Context dependent meaning
Even when it is appropriately used, it has an inherent ambiguous meaning; ¤12.50 can be interpreted as 12.5 units of some currency, but the currency itself is unknown, and can only be determined by information outside the use of the character in itself.
More likely, this sign was intended to mark the position of the national currency symbol into the national variants of ASCII (7-bit, 95 printable characters available), where a specific national body was reluctant to accept the dollar sign ($) as a kind of "universal sign" to denote "currency" or "money". The currency sign ¤ should then be replaced by the appropriate glyph, depending on audience (₤, ¥, ฿, ₱ etc.). But somehow, the neutral currency sign (¤) was to be used as a printable symbol in itself, and this usage was sufficient extended in the years of the first drafts of ISO 8859 to include it.
Using one and the same code point for different national currency symbols can be problematic in international communication. If, for example, an amount of £100 is written in an e-mail or on a website, and the software does not make sure that the same character set is used at both ends, it could be interpreted e.g. as ¥100, which is a much lower value than £100. (To put this into perspective, as of January 2013, ¥100 is worth approximately £0.70.)
|This section does not cite any references or sources. (March 2009)|
- Alternative separator in CSV files
- Delete sign when typing on paper for later OCR processing
- ¤ means delete previous character
- ¤¤ means delete previous word (i.e. back to previous space character)
- ¤¤¤ : delete entire line
- In Microsoft Word, the currency sign is used to indicate the end of a table cell in some viewing modes.
- On the Xbox 360, the currency sign becomes the Microsoft Points symbol when entered.
- In some versions of BASIC (notably in Soviet versions and ABC BASIC), the currency sign was used for string variables instead of the dollar sign. It was located on the keyboard and the character set table at the same position in many national keyboards (like Scandinavian) and eq versions of 7-bit ISO/IEC 646 ASCII, as the dollar sign is in US-ASCII. | <urn:uuid:864a3f40-7c24-4742-a78d-e26a2a2dd405> | CC-MAIN-2013-20 | http://en.wikipedia.org/wiki/%c2%a4 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.944865 | 851 | 3.703125 | 4 |
||This article needs additional citations for verification. (June 2010)
C-type asteroids are carbonaceous asteroids. They are the most common variety, forming around 75% of known asteroids, and an even higher percentage in the outer part of the asteroid belt beyond 2.7 AU, which is dominated by this asteroid type. The proportion of C-types may actually be greater than this, because C-types are much darker than most other asteroid types except D-types and others common only at the extreme outer edge of the asteroid belt.
Asteroids of this class have spectra very similar to those of carbonaceous chondrite meteorites (types CI and CM). The latter are very close in chemical composition to the Sun and the primitive solar nebula, except for the absence of hydrogen, helium and other volatiles. Hydrated (water-containing) minerals are present.
C-type asteroids are extremely dark, with albedos typically in the 0.03 to 0.10 range. Consequently, whereas a number of S-types can normally be viewed with binoculars at opposition, even the largest C-types require a small telescope. The potentially brightest C-type asteroid is 324 Bamberga, but that object's very high eccentricity means it rarely reaches its maximum magnitude.
Their spectra contain moderately strong ultraviolet absorption at wavelengths below about 0.4 μm to 0.5 μm, while at longer wavelengths they are largely featureless but slightly reddish. The so-called "water" absorption feature around 3 μm, which can be an indication of water content in minerals is also present.
The largest unequivocally C-type asteroid is 10 Hygiea, although the SMASS classification places the largest asteroid, 1 Ceres, here as well, because that scheme lacks a G-type.
C-group asteroids
See also asteroid spectral types.
C-group (Tholen)
In the Tholen classification, the C-type is grouped along with three less numerous types into a wider C-group of carbonaceous asteroids which contains:
C-group (SMASS)
In the SMASS classification, the wider C-group contains the types:
- B-type corresponding to the Tholen B and F-types
- a core C-type for asteroids having the most "typical" spectra in the group
- Cg and Cgh types corresponding to the Tholen G-type
- Ch type with an absorption feature around 0.7μm
- Cb type corresponding to transition objects between the SMASS C and B types
See also
- ^ Gradie et al. pp. 316-335 in Asteroids II. edited by Richard P. Binzel, Tom Gehrels, and Mildred Shapley Matthews, Eds. University of Arizona Press, Tucson, 1989, ISBN 0-8165-1123-3
- ^ Norton, O. Richard (2002). The Cambridge Encyclopedia of Meteorites. Cambridge: Cambridge University Press. pp. 121–124. ISBN 0-521-62143-7.
S. J. Bus and R. P. Binzel Phase II of the Small Main-belt Asteroid Spectroscopy Survey: A feature-based taxonomy, Icarus, Vol. 158, pp. 146 (2002). | <urn:uuid:bf20eab2-523c-42fb-98c2-64d34ac2498d> | CC-MAIN-2013-20 | http://en.wikipedia.org/wiki/C-type_asteroid | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.86804 | 686 | 3.578125 | 4 |
Implantation (human embryo)
||This article relies largely or entirely upon a single source. (September 2008)|
In humans (as in all other mammals, except for monotremes), implantation is the very early stage of pregnancy at which the embryo adheres to the wall of the uterus. At this stage of prenatal development, the embryo is a blastocyst. It is by this adhesion that the fetus receives oxygen and nutrients from the mother to be able to grow.
The reception-ready phase of the endometrium of the uterus is usually termed the "implantation window" and lasts about 4 days. The implantation window follows around 6 days after the peak in luteinizing hormone levels. With some disparity between sources, it has been stated to occur from 7 days after ovulation until 9 days after ovulation, or days 6-10 postovulation. On average, it occurs during the 20th to the 23rd day after the last menstrual period.
The implantation window is characterized by changes to the endometrium cells, which aid in the absorption of the uterine fluid. These changes are collectively known as the plasma membrane transformation and bring the blastocyst nearer to the endometrium and immobilize it. During this stage the blastocyst can still be eliminated by being flushed out of the uterus. Scientists have hypothesized that the hormones cause a swelling that fills the flattened out uterine cavity just prior to this stage, which may also help press the blastocyst against the endometrium. The implantation window may also be initiated by other preparations in the endometrium of the uterus, both structurally and in the composition of its secretions.
Adaptation of uterus
To enable implantation, the uterus goes through changes in order to be able to receive the embryo.
Furthermore, the surface of the endometrium produces a kind of rounded cells, which cover the whole area toward the uterine cavity. This happens about 9 to 10 days after ovulation. These cells are called decidual cells, which emphasises that the whole layer of them is shed off in every menstruation if no pregnancy occurs, just as leaves of deciduous trees. The uterine glands, on the other hand, decrease in activity and degenerate already 8 to 9 days after ovulation in absence of pregnancy.
The stromal cells originate from the stromal cells that are always present in the endometrium. However, the decidual cells make up a new layer, the decidua. The rest of the endometrium, in addition, expresses differences between the luminal and the basal sides. The luminal cells form the zona compacta of the endometrium, in contrast to the basalolateral zona spongiosa, which consists of the rather spongy stromal cells.
Decidualization succeeds predecidualization if pregnancy occurs. This is an expansion of it, further developing the uterine glands, the zona compacta and the epithelium of decidual cells lining it. The decidual cells become filled with lipids and glycogen and take the polyhedral shape characteristic for decidual cells.
It is likely that the blastocyst itself makes the main contribution to this additional growing and sustaining of the decidua. An indication of this is that decidualization occurs at a higher degree in conception cycles than in nonconception cycles. Furthermore, similar changes are observed when giving stimuli mimicking the natural invasion of the embryo.
Parts of decidua
The decidua can be organized into separate sections, although they have the same composition.
- Decidua basalis - This is the part of the decidua which is located basalolateral to the embryo after implantation.
- Decidua capsularis - Decidua capsularis grows over the embryo on the luminal side, enclosing it into the endometrium. It surrounds the embryo together with decidua basalis.
- Decidua parietalis - All other decidua on the uterine surface belongs to decidua parietalis.
Decidua throughout pregnancy
After implantation the decidua remains, at least through the first trimester. However, its most prominent time is during the early stages of pregnancy, during implantation. Its function as a surrounding tissue is replaced by the definitive placenta. However, some elements of the decidualization remain throughout pregnancy.
The compacta and spongiosa layers are still observable beneath the decidua in pregnancy. The glands of the spongiosa layer continue to secrete during the first trimester, when they degenerate. However, before that disappearance, some glands secrete unequally much. This phenomenon of hypersecretion is called the Arias-Stella phenomenon, after the pathologist Javier Arias-Stella.
Pinopodes are small, finger-like protrusions from the endometrium. They appear between day 19 and day 21 of gestational age. This corresponds to a fertilization age of approximately 5 to 7 days, which corresponds well with the time of implantation. They only persist for 2 to 3 days. The development of them is enhanced by progesterone but inhibited by estrogens.
Function in implantation
Pinopodes endocytose uterine fluid and macromolecules in it. By doing so, the volume of the uterus decreases, taking the walls closer to the embryoblast floating in it. Thus, the period of active pinocytes might also limit the implantation window.
Function during implantation
Pinopodes continue to absorb fluid, and removes most of it during the early stages of implantation.
Adaptation of secretions
|proteins, glycoproteins and peptides
secreted by the endometrial glands
|Placental protein 14 (PP14) or glycodelin|
|endometrial protein 15|
|Fibroblast growth factor 1|
|Fibroblast growth factor 2|
|Pregnancy-associated plasma protein A
|Stress response protein 27 (SRP-27)|
|Tissue plasminogen activator|
|Progesterone-dependent carbonic anhydrase|
Not only the lining of the uterus transforms, but in addition, the secretion from its epithelial glands changes. This change is induced by increased levels of progesterone from the corpus luteum. The target of the secretions is the embryoblast, and has several functions on it.
The embryoblast spends approximately 72 hours in the uterine cavity before implanting. In that time, it cannot receive nourishment directly from the blood of the mother, and must rely on secreted nutrients into the uterine cavity, e.g. iron and fat-soluble vitamins.
Growth and implantation
In addition to nourishment, the endometrium secretes several steroid-dependent proteins, important for growth and implantation. Cholesterol and steroids are also secreted. Implantation is further facilitated by synthesis of matrix substances, adhesion molecules and surface receptors for the matrix substances.
Implantation is initiated when the blastocyst comes into contact with the uterine wall.
To be able to perform implantation, the blastocyst first needs to get rid of its zona pellucida. This process can be called "hatching".
Lytic factors in the uterine cavity, as well as factors from the blastocyst itself are essential for this process. Mechanisms in the latter are indicated by that the zona pellucida remains intact if an unfertilized egg is placed in the uterus under the same conditions. A substance probably involved is plasmin. Plasminogen, the plasmin precursor, is found in the uterine cavity, and blastocyst factors contribute to its conversion to active plasmin. This hypothesis is supported by lytic effects in vitro by plasmin. Furthermore, plasmin inhibitors also inhibit the entire zona hatching in rat experiments.
The very first, albeit loose, connection between the blastocyst and the endometrium is called the apposition.
On the endometrium, the apposition is usually made where there is a small crypt in it, perhaps because it increases the area of contact with the rather spherical blastocyst.
On the blastocyst, on the other hand, it occurs at a location where there has been enough lysis of the zona pellucida to have created a rupture to enable direct contact between the underlying trophoblast and the decidua of the endometrium. However, ultimately, the inner cell mass, inside the trophoblast layer, is aligned closest to the decidua. Nevertheless, the apposition on the blastocyst is not dependent on if it is on the same side of the blastocyst as the inner cell mass. Rather, the inner cell mass rotates inside the trophoblast to align to the apposition. In short, the entire surface of the blastocyst has a potential to form the apposition to the decidua.
Adhesion is a much stronger attachment to the endometrium than the loose apposition.
The trophoblasts adhere by penetrating the endometrium, with protrusions of trophoblast cells.
There is massive communication between the blastocyst and the endometrium at this stage. The blastocyst signals to the endometrium to adapt further to its presence, e.g. by changes in the cytoskeleton of decidual cells. This, in turn, dislodges the decidual cells from their connection to the underlying basal lamina, which enables the blastocyst to perform the succeeding invasion.
Another ligand-receptor system involved in adhesion is proteoglycan receptors, found on the surface of the decidua of the uterus. Their counterparts, the proteoglycans, are found around the trophoblast cells of the blastocyst. This ligand-receptor system also is present just at the implantation window.
Invasion is an even further establishment of the blastocyst in the endometrium.
The protrusions of trophoblast cells that adhere into the endometrium continue to proliferate and penetrate into the endometrium. As these trophoblast cells penetrate, they differentiate to become a new type of cells, syncytiotrophoblast. The prefix syn- refers to the transformation that occurs as the boundaries between these cells disappear to form a single mass of many cell nuclei (a syncytium). The rest of the trophoblasts, surrounding the inner cell mass, are hereafter called cytotrophoblasts.
Invasion continues with the syncytiotrophoblasts reaching the basal membrane beneath the decidual cells, penetrating it and further invading into the uterine stroma. Finally, the whole embryo is embedded in the endometrium. Eventually, the syncytiotrophoblasts come into contact with maternal blood and form chorionic villi. This is the initiation of forming the placenta.
The blastocyst secretes factors for a multitude of purposes during invasion. It secretes several autocrine factors, targeting itself and stimulating it to further invade the endometrium. Furthermore, secretions loosen decidual cells from each other, prevent the embryo from being rejected by the mother, trigger the final decidualization and prevent menstruation.
The syncytiotrophoblasts dislodges decidual cells in their way, both by degradation of cell adhesion molecules linking the decidual cells together as well as degradation of the extracellular matrix between them.
Cell adhesion molecules are degraded by syncytiotrophoblast secretion of Tumor necrosis factor-alpha. This inhibits the expression of cadherins and beta-catenin. Cadherins are cell adhesion molecules, and beta-catenin helps to anchor them to the cell membrane. Inhibited expression of these molecules thus loosens the connection between decidual cells, permitting the syncytotrophoblasts and the whole embryo with them to invade into the endometrium.
The extracellular matrix is degraded by serine endopeptidases and metalloproteinases. Examples of such metalloproteinases are collagenases, gelatinases and stromelysins. These collagenases digest Type-I collagen, Type-II collagen, Type-III collagen, Type-VII collagen and Type-X collagen. The gelatinases exist in two forms; one digesting Type-IV collagen and one digesting gelatin.
The embryo differs from the cells of the mother, and would be rejected as a parasite by the immune system of the mother if it didn't secrete immunosuppressive agents. Such agents are Platelet-activating factor, human chorionic gonadotropin, early pregnancy factor, immunosuppressive factor, Prostaglandin E2, Interleukin 1-alpha, Interleukin 6, interferon-alpha, leukemia inhibitory factor and Colony-Stimulating Factor.
Factors from the blastocyst also trigger the final formation of decidual cells into their proper form. In contrast, some decidual cells in the proximity of the blastocyst degenerate, providing nutrients for it.
Prevention of menstruation
Human chorionic gonadotropin (hCG) not only acts as an immunosuppressive, but also "notifies" the mother's body that she is pregnant, preventing menstruation by sustaining the function of the corpus luteum.
Other factors secreted by the blastocyst are;
- ovum factor
- Embryo-derived histamine-releasing factor
- Tissue plasminogen activator as well as its inhibitors
- Fibroblast growth factor
- Transforming growth factor alpha
Implantation failure has diverse causes, including abnormal cytokine and hormonal signaling as well as epigenetic alterations. Recurrent implantation failure is a cause of female infertility. Therefore, pregnancy rates can be improved by optimizing endometrial receptivity for implantation. Evaluation of implantation markers may help to predict pregnancy outcome and detect occult implantation deficiency.
Luteal support is the administration of medication, generally progestins, for the purpose of increasing the success rate of implantation and early embryogenesis, thereby complementing the function of the corpus luteum.
- Wilcox AJ, Baird DD, Weinberg CR (1999). "Time of implantation of the Conceptus and loss of pregnancy". New England Journal of Medicine 340 (23): 1796–1799. doi:10.1056/NEJM199906103402304. PMID 10362823.
- Xiao, Y.; Sun, X.; Yang, X.; Zhang, J.; Xue, Q.; Cai, B.; Zhou, Y. (2010). "Leukemia inhibitory factor is dysregulated in the endometrium and uterine flushing fluid of patients with adenomyosis during implantation window". Fertility and Sterility 94 (1): 85–89. doi:10.1016/j.fertnstert.2009.03.012. PMID 19361790.
- Aboubakr M. Elnashar, Gamal I. Aboul-Enein. Endometrial receptivity. Middle East Fertility Society Journal, Vol. 9, No. 1, 2004, pp. 10-24
- 6.2 Implantation stages from embryology.ch at by the universities of Fribourg, Lausanne and Bern (Switzerland). Retrieved May, 2012
- "Implantation stages". Human Embryology. Online course in embryology for medicine students developed by the universities of Fribourg, Lausanne and Bern (Switzerland) with the support of the Swiss Virtual Campus. Retrieved 6 December 2011.
- Boron, Walter; Emile Boulpaep (2004). Medical Physiology: A Cellular And Molecular Approaoch. Oxford: Elsevier. ISBN 1-4160-2328-3. OCLC 61527528.[page needed]
- Cakmak, H.; Taylor, H. S. (2010). "Implantation failure: Molecular mechanisms and clinical treatment". Human Reproduction Update 17 (2): 242–253. doi:10.1093/humupd/dmq037. PMC 3039220. PMID 20729534. | <urn:uuid:4dab5b14-1f06-4bf2-b66a-e923ca785ee6> | CC-MAIN-2013-20 | http://en.wikipedia.org/wiki/Implantation_(human_embryo) | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.873243 | 3,471 | 4.03125 | 4 |
Clever application design and the code writing part should take care of the frequent changes that are done during the development and the maintaining phase of an application. Usually, many changes are involved when a new functionality is added to an application. Those changes in the existing code should be minimized, since it's assumed that the existing code is already unit tested and changes in already written code might affect the existing functionality in an unwanted manner.
The Open Close Principle states that the design and writing of the code should be done in a way that new functionality should be added with minimum changes in the existing code. The design should be done in a way to allow the adding of new functionality as new classes, keeping as much as possible existing code unchanged. The name Open/Closed Principle has been used in two ways. Both ways use inheritance to resolve the apparent dilemma, but the goals, techniques, and results are different.
Meyer's Open/Closed Principle
Bertrand Meyer is generally credited as having originated the term Open/Closed Principle, which appeared in his 1988 book Object Oriented Software Construction. The idea was that once completed, the implementation of a class could only be modified to correct errors; new or changed features would require that a different class be created. That class could reuse coding from the original class through inheritance. The derived subclass might or might not have the same interface as the original class.
Meyer's definition advocates implementation inheritance. Implementation can be reused through inheritance but interface specifications need not be. The existing implementation is closed to modifications, and new implementations need not implement the existing interface.
Polymorphic Open/Closed Principle
During the 1990s, the Open/Closed Principle became popularly redefined to refer to the use of abstracted interfaces, where the implementations can be changed and multiple implementations could be created and polymorphically substituted for each other.
In contrast to Meyer's usage, this definition advocates inheritance from abstract base classes. Interface specifications can be reused through inheritance but implementation need not be. The existing interface is closed to modifications and new implementations must, at a minimum, implement that interface.
Robert C. Martin's 1996 article "The Open-Closed Principle" was one of the seminal writings to take this approach. In 2001 Craig Larman related the Open/Closed Principle to the pattern by Alistair Cockburn called Protected Variations, and to the David Parnas discussion of information hiding.
- SOLID – the "O" in "SOLID" stands for the open/closed principle
- Robert C. Martin "The Open-Closed Principle", C++ Report, January 1996, pp. 1
- Robert C. Martin "The Open-Closed Principle", C++ Report, January 1996
- Craig Larman, "Protected Variation: The Importance of Being Closed", IEEE Software May/June 2001, pp. 89-91 | <urn:uuid:c5bd2213-153e-4590-9838-3b656a23e16d> | CC-MAIN-2013-20 | http://en.wikipedia.org/wiki/Open/closed_principle | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.927726 | 593 | 3.59375 | 4 |
March 03, 2004
Lake Waikaremoana was created only 2,200 years ago (approximately) by a massive rock and earth landslide, which blocked a narrow gorge along the Waikaretaheke River. Water backed up behind this natural dam to form a lake up to 248 metres (814 ft) deep. Another landslide, around 18,000 years ago, formed the nearby lake Lake Waikareiti. Thick sandstone and some limestone bands form tilted escarpments such as the Panekiri Bluffs, seen on the far side of the lake in this picture. Lake Waikaremoana is located in the Te Urewera National Park on New Zealand's North Island. | <urn:uuid:8cd9b84d-0044-4f33-a963-fe16302e2bee> | CC-MAIN-2013-20 | http://epod.usra.edu/blog/2004/03/lake-waikaremoana-.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.959054 | 143 | 3.546875 | 4 |
Dr. Pamela Gore
Georgia Perimeter College
- Briefly contrast weathering and erosion.
- Contrast chemical and physical (or mechanical) weathering.
- List and describe the types of physical (or mechanical) weathering.
- List and describe the types of chemical weathering.
- List the products resulting from the chemical weathering of Igneous rocks.
- List and discuss the factors that influence the type and rate of rock weathering.
This section addresses, in whole or in part, the following Georgia GPS standard(s):
- Describe processes that change rocks and the surface of the Earth.
- Describe soil as consisting of weathered rocks and decomposed organic material.
This section addresses, in whole or in part, the following Benchmarks for Scientific Literacy:
- Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions)
while other changes happen very slowly (such as uplift and wearing down of mountains).
The earth's surface is shaped in part by the motion of water and wind over very long times, which act to level mountain ranges.
- Although weathered rock is the basic component of soil, the composition and texture of soil and its fertility
and resistance to erosion are greatly influenced by plant roots and debris, bacteria, fungi, worms, insects, rodents, and other organisms.
-- INSERT TEXT HERE -->
This section addresses, in whole or in part, the following National Science Education Standards:
- Land forms are the result of a combination of constructive and destructive forces. Constructive forces include crustal deformation, volcanic eruption, and deposition of sediment, while destructive forces include weathering and erosion.
- Some changes in the solid earth can be described as the "rock cycle." Old rocks at the earth's surface weather, forming sediments that are buried, then compacted, heated, and often recrystallized into new rock. Eventually, those new rocks may be brought to the surface by the forces that drive plate motions, and the rock cycle continues.
- Soil consists of weathered rocks and decomposed organic material from dead plants, animals, and bacteria. Soils are often found in layers, with each having a different chemical composition and texture.
- Living organisms have played many roles in the earth system, including affecting the composition of the atmosphere, producing some types of rocks, and contributing to the weathering of rocks.
Weathering is the BREAKDOWN of rock to form sediment.
Erosion is the TRANSPORTATION of rock particles (or sediment) that have formed by weathering processes.
Types of weathering:
A. Physical or mechanical weathering
Frost wedging - water expands when it freezes
Talus slope, Lost River, West Virginia
Shale chips, West Virginia
Exfoliation or unloading -
Thermal expansion -
- repeated daily heating and cooling of rock;
- heat causes expansion; cooling causes contraction.
- different minerals expand and contract at different rates causing stresses along
B. Chemical weathering
Rock reacts with water, gases and solutions (may be acidic); will add or remove elements
Dissolution (or solution)-
- Several common minerals dissolve in water
- Limestone and marble contain calcite and are soluble in acidic water
- Marble tombstones and carvings are particularly susceptible to chemical weathering by dissolution.
Note that the urn and tops of ledges are heavily weathered, but the inscriptions are somewhat sheltered and remain legible.
Photo taken in an above-ground cemetery in New Orleans
- Caves and caverns typically form in limestone
- speleothems are cave formations
- speleothems are made of calcite
- form a rock called travertine
- stalactites - hang from ceiling
- stalagmites - on the ground
- Areas underlain by limestone in humid climates typically have karst topography,
which is characterized by:
- disappearing streams,
General view of karst topography, St. Paul Group, Chambersburg Limestone. Pennsylvania, north of Clear Spring, MD.
Note small closed depressions.
Small sinkhole within a larger sinkhole, west of Albany, GA
Street detours around a large sinkhole in Albany, GA near Radium Springs
Chinese Tower Karst. Photo from Microsoft Clip Gallery.
Oxidation - Oxygen combines with iron-bearing silicate minerals causing "rusting".
Iron oxides are produced that are red, orange, or brown in color.
Iron-bearing silicate minerals that undergo oxidation include the following:
Iron oxides are produced by oxidation of iron-bearing silicate minerals.
These minerals are iron oxide minerals:
- Iron oxides are red, orange, or brown in color
- Mafic rocks such as basalt (which may contain olivine, pyroxene, or amphibole)
weather by oxidation to an orange color
- "Georgia Red Clay" derives its color from the oxidation of iron bearing minerals
Broken piece of fine-grained basalt from a dike near Stone Mountain, GA.
Note the black color of the unweathered rock, and the weathering rind colored by iron oxides.
The weathering rind has two distinct layers, an inner yellowish layer and an outer orange layer.
Sample is about 10 cm in width.
Weathering Rind, Wilhite Formation, eastern Tennessee
- Silicate minerals weather by hydrolysis to form CLAY.
- Feldspar alters to clay (kaolinite) plus dissolved materials (ions).
Kaolinite (or kaolin) is a pure, white clay mined in central Georgia along a line from Augusta to Macon to Columbus.
Kaolinite is used for shiny coating on paper, and is used in rubber (tires), paints, plastics, ceramics, and many other products.
References on kaolin mining in Georgia:
Kaolin mine, central Georgia
- Feldspars are stable at high temperatures and pressures (but not at the
temperatures and pressures of the Earth's surface)
- Clays are stable under conditions at the Earth's surface
- Feldspars and clays are similar in composition.
- Feldspar readily alters to clay when in contact with acid and water.
- Iron-bearing silicate minerals weather to form clays by hydrolysis (in addition to
Spheroidal weathering in jointed basalt, Culpeper Basin, Virginia
Spheroidal weathering is caused by chemical weathering of jointed rocks.
The jointed rocks weather to form roughly spherical shapes.
C. Biological weathering
Organisms can assist in breaking down rock into sediment or soil.
Photo from Microsoft Clip Gallery
- Roots of trees and other plants
- Lichens, fungi, and other micro-organisms
- Animals (including humans)
Lichen on boulder, Cartersville, GA
Closeup of lichen, Stone Mountain GA
What happens when granite is weathered?
- First, unweathered granite contains these minerals:
- Na Plagioclase feldspar
- K feldspar
- Lesser amounts of biotite, amphibole, or muscovite
- The feldspars will undergo hydrolysis to form kaolinite (clay) and Na and K ions
- The Na and K ions will be removed through leaching
- The biotite and/or amphibole will undergo hydrolysis to form clay, and oxidation to
form iron oxides.
- The quartz (and muscovite, if present) will remain as residual minerals because they
are very resistant to weathering.
- Weathered rock is called saprolite
- Weathered rock fragments are one of the constituents of soil.
- What happens after this?
- Quartz grains may be eroded, becoming sediment. The quartz in granite is sand-sized; it becomes quartz sand.
The quartz sand will ultimately be transported to
the sea where it accumulates to form beaches.
- Clays will ultimately be eroded and washed out to sea. Clay is fine-grained and
remains suspended in the water column; it may be deposited in quiet water.
- Dissolved ions will be transported by rivers to the sea, and will become part of the salts in the sea.
Rates of weathering
Factors influencing the rate of weathering include:
- Amount of surface area exposed to chemical weathering.
As the rock breaks down into smaller pieces, more surface area is exposed, and the rock weathers faster.
The presence of cracks or joints in the rock can allow water to penetrate and increase the rate of weathering.
- Different minerals weather at different rates.
Marble and limestone, which are composed of calcium carbonate, dissolve readily in weakly acidic solutions.
Silicate minerals weather in the same sequence as they crystallize. (Bowen's Reaction Series). Olivine crystallizes first from a magma, and so is the first to weather.
Quartz crystallizes last from magma, and so it is the most resistant to weathering.
- Climate influences weathering rates, particularly temperature and the availability of water.
Warm temperatures and abundant moisture lead to RAPID WEATHERING.
Return to Earth & Space Science page
Return to Georgia Geoscience Online
Page created by Pamela J.W. Gore
Georgia Perimeter College,
Page created February 25, 2005
Links updated October 13, 2008 | <urn:uuid:f6c32fee-70b0-4757-8492-9f6f57d42b23> | CC-MAIN-2013-20 | http://facstaff.gpc.edu/~pgore/Earth&Space/GPS/Weathering.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.898225 | 2,005 | 3.984375 | 4 |
The Brain Stem
The brain stem connects the cerebrum with the spinal cord. It is the most primitive part of the brain and is involved mainly in regulating vital processes. At the bottom of the brainstem is the medulla oblongata, which has nerve sensors that control many vital processes such as breathing and heartbeat.
Right above the medulla oblongata is the pons, which connects the hemispheres of the cerebellum. Above the pons is the midbrain, which controls eye movement and the size of the pupils. At the top of the brain stem is the diencephalon. The diencephalon contains the thalamus and the hypothalamus
Deep inside the brain stem is the reticular formation, a network of nerve fibers that help regulate the brain's level of awareness. It runs up from the medulla oblongata through the pons and midbrain. Sensory impulses passing through the brainstem stimulate the reticular formation, which then stimulates activity and alertness around the cerebral cortex.
The Medulla Oblongata
The Thalamus and Hypothalamus
The Reticular Formation
The medulla oblongata, found at the bottom of the brain stem, morphs into the pons above it. Below it, the medulla oblongata makes a transition into the spinal chord (at the foramen magnum). Sensory and motor nerve fibers that connect the brain to the rest of the body cross over to the opposite side in the medulla oblongata, which is why the left part of the brain oversees the right side of the body and vice versa.
The pons can be identified as a bulge in the brain stem right in front of the cerebellum. It consists of large nerve fiber bundles that connect the two lobes of the cerebellum. The fibers also connect each side of the cerebellum to the cerebral hemisphere on the opposite side. The structure's main purpose is to relay messages between the cerebral cortex and the medulla oblongata.
The midbrain contains relay stations for neurons transmitting messages to the cerebral cortex. It also has several reflex centers which input sensory commands and output motor commands. Relay and reflex stations for auditory and visual functions are found at the top of the midbrain. A pair of nuclei, the superior colliculus, controls reflex actions of the eye. Another pair of nuclei, the inferior colliculus, controls reflex actions of the ear. At the bottom of the midbrain are relay/reflex centers for pain, temperature, and touch. The red nucleus and substantia nigra, also found at the bottom of the midbrain, are associated with movement.
The thalamus and the hypothalamus are positioned beneath the cerebrum, connecting it to the brainstem. The thalamus is formed by two round masses of gray tissue, and it is found in the middle of the brain between the cerebral hemispheres. It receives most all sensory signals (except for smell), and sends out all motor signals.
The hypothalamus can be found directly below the thalamus at the base of the brain. It controls or is involved in many vital drives and processes such as eating and drinking, body temperature, sleep, emotions, and sexual activity. It controls the function of internal organs through the autonomic nervous system, collaborates with the pituitary gland, and helps coordinate brain stem activity.
The reticular formation is a formation of nuclei that runs up through the brain stem. It helps control respiration, cardiovascular function, digestion, alertness, and sleep. It also decide which of the constant flux of sensory messages are received by the cerebrum. | <urn:uuid:9de1f355-d07e-4649-9295-ee631dd054ca> | CC-MAIN-2013-20 | http://library.thinkquest.org/26812/brainstem.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.911059 | 756 | 4.28125 | 4 |
Search Mathematical Communication:
Topic Teaching Tip(s): General principles of mathematical communication | Using visuals
This webpage includes links to effective mathematical visuals online, including proofs without words. Also included is a list of tools for visualizing math (both commercial and free), and a list of resources both online and in the literature that present pedagogical strategies, theory, research, &/or experience, both for teaching students to communicate math via visualizations, and for using visualizations to help students learn math.
To rate this resource on a 1-5 scheme, click on the appropriate icosahedron:
MathDL Mathematical Communication
This review was published on August 04, 2011 | <urn:uuid:15decfa8-8186-45e9-bc08-aa6aa960023b> | CC-MAIN-2013-20 | http://mathdl.maa.org/mathDL/62/?pa=mathCommunication&sa=viewResourceEntry&resourceId=81 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.874141 | 139 | 3.578125 | 4 |
A Sub Routine is a small self-contained section of code that completes a task or process. If you think about the theory of modular programming where you end up with small solvable problems – these are the sub-routines that together make up the program. There are a number of advantages of using sub routines:
- You can reuse your code :- in a game a player will take many turns and therefore it makes sense to have a sub-routine that deals with player-turns( ). Likewise you’d need to check if someone has won many times and therefore a iswinner( ) subroutine would be useful. Notice that subroutines are written with normal brackets following them.
- It makes your program easier to maintain:- If you only have one place in your program where you write to a file and that process needs to change you only have to maintain one section of code.
- If you need a hashtable routine and have already written one it’s very easy to cut and paste the routine from one program to another.
Earlier we said that subroutines are written with trailing brackets. This is so we can pass values to the subroutines, these inputs are known as parameters or variables e.g.
getSquareArea( sidea, sideb)
When is comes to returning values there are two types of Sub Routine (Procedures and Functions). Procedures don’t return values they just do something. Functions (like Maths ones) do return values using the return keyword.
In Python, like many modern languages, we don’t differentiate between procedures and functions we just have functions. To create a function we use the def keyword e.g.
def getSquare( sidea, sideb) return sidea * sideb
One of the frequent questions regards to returning values from routines is how to return more than one value. Python has a very useful feature that allows us to create a tuple (type of array) on the fly e.g.
def getSquareData ( sidea, sideb) perimeter = sidea + sideb + sidea + sideb area = sidea * sideb return [ perimeter , area ]
Note: return perimeter, area and return (perimeter,area) would also work.
Last snippet :- Python allows you to define default values for your routines so you could declare our getSquare routine as:
def getSquare( sidea = 0, sideb = 0) | <urn:uuid:2504a12e-c259-4617-81ae-e23cf91cfe11> | CC-MAIN-2013-20 | http://moo.compu2learn.co.uk/course/view.php?id=31 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.887301 | 517 | 4.34375 | 4 |
Pauling's idea for a plasma substitute was not an unfamiliar one. Gelatin was already in use as a plasma replica during the
late 1930s and early 1940s, but its viscosity and tendency to condense at room temperature made it a poor candidate. The U.S.
military needed something quick and efficient that could be used in field hospitals with minimal preparation. The Caltech
team, however, was not yet ready to discard gelatin as a potential candidate. Pauling hoped that, through chemical processes,
he might be able to transform standard commercial-grade gelatin into a workable substance.
Between June 1942 and May 1944, Caltech received approximately $20,000 from the CMR in support of the project. During that
time, Pauling and his team were able to successfully develop a possible plasma substitute through the polymerization and oxidation
of gelatin. This substance, first referred to as polyoxy gelatin and eventually known as Oxypolygelatin, was superior to
its unmodified counterpart in several ways. Because it was liquid at room temperature, Oxypolygelatin did not require the
same pre-injection heating that previous substitutes required, allowing it to be used quickly and without the help of heating
implements. Furthermore, thanks to the creation of large chain-like molecules during the preparation process, oxypolygelatin
was retained in the bloodstream for longer periods, allowing the patient's body more time to manufacture natural plasma. Finally,
where gelatin contained pyrogens (fever-causing molecules), Oxypolygelatin did not - a property resulting from the addition
of hydrogen peroxide.
To a chemist's eye, Oxypolygelatin appeared to be an acceptable substitute for human plasma. Pauling knew, however, that his
own tests were not enough to convince the CMR of the substance's viability. He needed a medical expert's stamp of approval.
Pauling called on Dr. Thomas Addis - the renal expert who cured Pauling's near-fatal case of glomerular nephritis - to analyze
the effects of Oxypolygelatin on human organs. Addis accepted the challenge, bringing fellow researcher Dr. Jean Oliver to
the project as well. Over the next two years, Addis and Oliver subjected Oxypolygelatin to a battery of tests, eventually
confirming its potential as a plasma substitute.
Despite Pauling's enthusiasm and Addis' promising results, the CMR did not believe Oxypolygelatin to be sufficiently superior
to the pre-existing gelatin substance and, in the spring of 1944, the committee refused Pauling's request for a renewal of
contract. Surprised by the committee's decision, he submitted a second request, asking that his contract be renewed for the
period of four months, with no additional funding from the OSRD. His request was granted but, due to empty coffers, no progress
was made. Pauling applied again in June, this time requesting extra resources for the project. Again, he was denied.
Frustrated with the lack of support, Pauling and his team scraped together enough residual funds to allow for one more series
of experiments. Pauling began injecting mice and rabbits with his synthetic plasma, carefully monitoring their health and
examining blood samples to determine the effects of the treatment. The results were satisfactory but not enough to put the
project back in the good graces of the CMR. Pauling knew that the only way to stimulate interest (and funding) for the project
was to prove that his substance could be used in humans. In September of 1944, twelve patients at the Los Angeles General
Hospital were injected with Oxypolygelatin, all exhibiting favorable reactions. Pauling had the results he needed. | <urn:uuid:82546e1f-ece8-4d97-bea2-a91e2d3b6325> | CC-MAIN-2013-20 | http://osulibrary.orst.edu/specialcollections/coll/pauling/war/narrative/page33.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.959301 | 781 | 3.609375 | 4 |
Stonehenge is a prehistoric monument located in the English county of Wiltshire, about 2 miles west of Amesbury and 8 miles north of Salisbury. One of the most famous prehistoric sites in the world, Stonehenge is composed of earthworks surrounding a circular setting of large standing stones. Produced by a culture with no written language, dating much earlier than the first cultures that did leave written records, Stonehenge is steeped in wonder and mystery.
Many theories abound about its origin, ranging from the academic worlds of archaeology and anthropology to the mystical realms of the mythological, extraterrestrial, paranormal and supernatural. This multiplicity of theories, some of them very colorful, is often called the "Mystery of Stonehenge." Recently an ambitious group of Michiganders took up the challenge and now openly declare the mystery solved. Given the modern anthropological and archaeological evidence, along with Michigan's unique relationship to these ancient English builders, they may be right.
Vikings, Phoenicians, Egyptians and the lost tribe of Israel in Michigan? According to historians, Michigan may very well have been home to these groups including several other mysterious ancients at some point in its prehistoric past. Following an ancient trail of archaeological evidence, a stone circle similar in character to Stonehenge was found in 1985 on Lake Michigan's Beaver Island that could have been built by any one of these ancient groups. Peculiar to these stones are their exact relationships to star positions, later research revealing an additional alignment with the midsummer solstice. The thing that perplexed archaeologists most was the fact that the bands of Native Americans indigenous to this area never created stone monuments. So who made it? The anthropological fingerprints suggest they were constructed by the same builders of Stonehenge from thousands of years ago.
The first academic effort to survey and understand Stonehenge was made around 1640 by John Aubrey, antiquarian and biographer, England's first archeologist. He declared Stonehenge the work of Druids. This view was greatly popularized by William Stukeley, an English scholar of sacred history and occult sciences. Aubrey also contributed the first measured drawings of the site, which permitted greater analysis of its form and significance. From this work, he was able to demonstrate an astronomical role in the stones' placement. The English architect John Wood was to undertake the first truly accurate survey of Stonehenge in 1740 and also credited the monument to the Druids. Wood's interpretation of the monument as a place of pagan ritual however was vehemently attacked by Stukeley who saw the Druids not as pagans, but as biblical patriarchs. Religious historians suggest that the Druids eventually migrated east becoming the ancient fathers of European Dutch Reformers who in modern times immigrated to the United States concentrating in pockets around West Michigan.
Armed with the knowledge of Michigan's multiple connections to Stonehenge and fueled by a rock-solid upright desire to know the unknown, a group of amateur archaeoastronomical and physiological scientists calling themselves the Michigan DRUIDS endeavored to construct a replica of Stonehenge with the intention of unraveling and unveiling its ancient mysteries. With funding provided by the Foundation for Neolithic Studies, the Stonehenge Rivertown Project, originally commissioned in summer 2008, finally broke permafrost ground several solstices later. On February 13th, 2010 they were successful in completing a 1/3rd scale replica of Stonehenge at the MacKay Jaycees Family Park in Grand Rapids, Michigan. The monument built out of Michigan's most abundant natural raw material is appropriately named Snowhenge.
Standing 6.5 feet tall and 30 feet in diameter and consisting of nearly 1000 cubic feet of packed snow, Snowhenge's 12 pillars and 12 lintels are perfectly aligned astronomical markers. Looking directly through the hole in the center of pillar 3 soon after sunset on Winter Solstice extraordinarily reveals an almost equilateral triangle formed by the visible planets Saturn (left), Mars (top), and Venus (right). A curious carving on pillar 4 shows four stars inside a trapezium which matches the Trapezium Star Cluster in the Orion Nebula. The imaginary end point of a line dissecting the trapezium matches the coordinates of the star Sirius, the brightest star in the Milky Way. An obelisk inside the snow circle marks the passage of the sun as its shadow moves in a figure eight on the ground below. Stone plaques strategically placed on the ground display the constellations of the zodiac. Outside the circle, three pairs of standing snowmen show where the sun rises and sets for each of the solstices and equinoxes. Every key point also has a rock plaque denoting its seasonal significance engraved with a simple phrase like "Midsummer Solstice Sunrise". Others describe local area seasonal events such as "Blandford Sugarbush", "Grand Rapids Festival of the Arts", "28th Street Metro Cruise", "Art Prize" and "Celebration on the Grand". The 12 lintels, supported by 144 rods of ice rebar, also contain markings that coincide with the orbital patterns of Earth and Venus which are designed to forecast solar eclipses, the appearance of comets, and the end of the world on December 23rd of 2012, exactly matching the Mayan calendar prediction. What's most truly remarkable, pillar 1 is precisely parallel with 28th Street! Curiously, the phenomenon known as global warming which has created isolated heat zones around the globe inversely causes cold spots on the opposite side of the globe. Numerous consecutive years of record heat spikes in Perth, Australia are directly responsible for the extraordinary cold snaps at MacKay Jaycees Family Park which will amazingly keep Snowhenge frozen all year round.
Within no time a media frenzy ensued, mobile satellite news trucks flocked to the MacKay Jaycees Family Park to cover the breaking story. In the FOX 17 news interview immediately following the Michigan DRUIDS announcement, Peter Salisbury explained, "When contemplating unexplained prehistoric mysteries, some people exercise unusual logic. Strive toward reasonable answers, that's our motto. The key to solving the ancient enigma of Stonehenge hinges on solving the mystery of who the DRUIDS really were. Stonehenge exists by virtue of its purpose. Knowing who the DRUIDS were and what they stood for, leads us to discover their true purpose for building Stonehenge."
Who were these ancient DRUIDS? There are several prominent theories:
- Healers: Doctors Relieving Unbearable Illnesses with Dolerite Stones
- Priests: Doing Religion Usually In Dark Suits
- Mystics: Delving in Religion Utilizing Incense & Dark Seances
- Engineers: Displacing Rocks Using Intelligence, Determination, and Science
- Architects: Designers Revolutionizing Urban Interior Development with Style
- Astronomers: Dudes Reaching Up Into Dark Sky
- Undertakers: Decomposing Remains Under Immense Distinguishing Sepulchers
There are also many "colorful" theories less accepted by mainstream historians and anthropologists:
- Aliens: Distant Reptiles Up In Deep Space
- ET's: Driving Real UFOs In Deep Space
- Activists: Downtrodden Rebel Underlings Intent on Doing Something
- Pacifists: Drifters Reclining Usually Instead of Doing Stuff
- Politicians: Disguising Rhetoric Under Illusions of Democratic Solutions
- Hippies: Dudes Rocking Using Intense Drugs & Stuff
- Drunks: Drinking Responsibly Under the Influence of Brewed Substances (DRUIBS)
Realizing that building Snowhenge would require a huge collective effort by fellow Druids, Peter Salisbury called together family members, friends and their family members to mimic the kind of work force that built Stonehenge. This solitary act proved to be the golden key that unlocked the mystery. Organizing this band of associated individuals into a single, massive, communal effort required one special belief. This mystical, magical, non-religious singular faith was a common conviction that this project was going to be FUN!
Meticulous research exploring the world archive of ancient manuscripts and glyphs, countless hours spent painstakingly excavating digs at stone circle sites around the globe, and after nearly two dozen keystrokes pressed executing exhaustive Google Internet searches, Peter Salisbury discovered an astonishing truth! The ancient DRUIDS were NOT some neo-pagan religious organization, but instead were the ancient forerunners to the Freemasons, an exclusive fraternity known as Doing Ridiculously Unbelievable Inexplicable Designs with Stone. Their intention was to instill awe and wonder in the eyes of the beholder, to make the onlooker think inquisitively. Loosely translated, Stonehenge in primitive Celtic is "Stohn-hendjeh" meaning "How dey do dat?" and in old Welsh dialect it's the close variant "Stohn-whendgeh" meaning "Why dey do dat?”. The movement caught on rapidly, spreading quickly around the ancient globe with chapters opening up at Easter Island in Chille, Mancho Picho in Peru, Chichen Itza in Yucatan Mexico and most prominently at the Giza Plateau in Cairo, Egypt. No matter the project however, the underlining purpose in all their efforts was to bring families together, all in the name of fun. Respectively, the Michigan DRUIDS derive their name from the original ancient DRUIDS calling themselves, Deliberately Replicating Unbelievable Inexplicable Designs with Snow (aka: Doing Ridiculous Undertakings In Deep Snow).
Modern anthropological and archaeological evidence has conclusively determined that Stonehenge was NOT a religious temple, a supernatural site for healing, an astronomical calendar, a Neolithic burial site, an extraterrestrial landing zone, or even really big park benches. Contemporary human psychology has solved the mystery, now declaring that Stonehenge was just a bunch of friends having some good ol' fashioned family fun with their spouses and kids. The ancient DRUIDS did it with stone, the Michigan DRUIDS do it with snow. No matter the medium, the DRUIDS purpose remains the same - do it bigger, live it larger, play it harder, have some fun. | <urn:uuid:ded92b1d-1f99-403d-8bf2-b835993a42fb> | CC-MAIN-2013-20 | http://snowhenge.blogspot.com/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.939987 | 2,115 | 3.625 | 4 |
The Convention on the Rights of the Child defines children as every "human being below the age of eighteen years unless under the law applicable to the child, majority is attained earlier". Some English definitions of the word child include the fetus and the unborn. Biologically, childhood is between birth and puberty. In a developmental definition, childhood is the age group between infancy and adulthood. Some classify Youth or adolescence between childhood and adulthood. Legally, being considered "youth" might give special treatment under the law (e.g. criminal law or entitlements). In general, children have different rights than adults, and they are under the care of an adult until they reach legal maturity.
It is quite recent, that children are considered a unique and separate population group that deservice special children's policy. Not so long ago, children were view as property, completely at the disposal of the adults surrounding them. The international law, and in particular the growing consensus on the extension of basic human rights in the twentieth century led to the acceptance of the autonomy of children as well as the acknowledgment of the child as an individual human being with special needs and rights.
The Convention on the Rights of the Child was adopted in 1989. It is a set of universally agreed standard and obligations to protect the rights of children regardless of race, colour, gender, language, religion, opinions, origins, wealth, birth status or ability. It is the first legally binding international instrument to incorporate the full range of human rights—civil, cultural, economic, political and social rights. it was signed by 192 of the 192 UN member countries.
In 2002, leaders from 189 countries came together at the United Nations for a Special Session of the UN General Assembly on Children. This led to an international agreement on protecting and promoting children's rights, called A World Fit for Children. This agreement sets 21 time-bound goals for children's well-being in the next decade, to be achieved in conjunction with the Millennium Development Goals.
Key Numbers on Children worldwide
In 2009, 6,775 million children and young people aged 0-14 lived in this world. This is an increase from 5,2 billions in 1990. The number of young people will increase further, numbering in 2025 (projected) 7,950 million. This increase in absolute numbers stands in contrast to the relative share of this age group to the total world population. The share of children and young people aged 0-14 in the world population has decreased from 32.9% in 1990 to 27.5% in 2009. This reflects a growth rate of 1.3% annually which is however projected to decrease to 1.1% in the period 2009/2015 and further decrease to 0.9% between 2015-2025. This trend is the same for all countries but there are regional differences in both absolute and relative changes.
World Bank Infant Mortality map
(Iframe URL not in list of trusted pages)
- Adolescent fertility rate
- The 2010 Global Education Digest: Datasets
- Tertiary attainment
- Child Marriage
- African Child Policy Forum
- The Children's Society
- The Good Childhood Index
- ↑ http://www2.ohchr.org/english/law/crc.htm
- ↑ Ben-Arieh, A. (2006). "Measuring and monitoring the well-being of young children around the world". Background paper prepares for the Education for All Global Monitoring Report 2007, UNESCO. Available at: http://unesdoc.unesco.org/images/0014/001474/147444e.pdf
- ↑ Table with Population Data from The World Bank. Retrieved on 24 June, 2011, from: http://data.worldbank.org/sites/default/files/gstable6.pdf and can be compiled from here (Population): http://data.worldbank.org/data-catalog/global-statistics
OECD countries: Statistics on Child well-being | <urn:uuid:408f8ba9-f7ec-48ff-8e7f-effe5c0717e4> | CC-MAIN-2013-20 | http://wikiprogress.org/index.php/Children | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.912282 | 816 | 4.375 | 4 |
This booklet is a short analysis of the role of the Penn family and other early Quakers in the Transatlantic Slave Trade and European expansionism in the North Americas.
As far as I am aware this story, the links between the different generations of the Penn family, has never before been told. It is pertinent to ask, “Why is this so?” The Penn family was at the heart of the English Revolution in the 17th Century and of every important event of British colonial expansionism from the colonisation of Ireland, Jamaica and the East Coast of North America. Yet, especially in Bristol, where the family had such strong connections, citizens are unaware of either the Penn family’s role in shaping the way we live or that their actions created social and class tensions that are still being played out today.
In fact, the Penn family, when it is referred to at all, is portrayed in Bristol as being either brave seafarers (Admiral Sir William Penn is celebrated in Bristol’s St Mary Redcliffe Church) or with kindly, if not saintly, reverence (such as the statue of William Penn in Millennium Square and his introspective Quaker writings that can be found in most, if not all, of the city’s Quaker Meeting Rooms).
What is never mentioned in public is the full story of the Penns, including that: | <urn:uuid:e330ff27-9d45-405c-b577-f9f4f1025cd0> | CC-MAIN-2013-20 | http://www.activedistributionshop.org/shop/pamphlets/2381-the-life-family-of-william-penn-.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.969351 | 281 | 3.671875 | 4 |
Eyelash vipers are arguably the world's most beautiful snakes - and one of its most dangerous. Found in Central and South America, these small, slender venomous snakes are far from typical pit-vipers. Distinctive modified scales over their eyes have the appearance of eyelashes, and go a some way to help camouflage these otherwise highly coloured snakes. Unusually, the scales of eyelash vipers are rough, which offers protection from the branches in their forest homes. Eyelash vipers have accidently been sent all over the world in shipments of bananas.
Scientific name: Bothriechis schlegelii
The following habitats are found across the Eyelash viper distribution range. Find out more about these environments, what it takes to live there and what else inhabits them.
Discover what these behaviours are and how different plants and animals use them.
Additional data source: Animal Diversity Web
The eyelash viper (Bothriechis schlegelii) is a venomous pit viper species found in Central and South America. Small and arboreal, these snakes are characterized by their wide array of color variations, as well as the superciliary scales over the eyes. Often present in zoological exhibits. Named after the German ornithologist, Hermann Schlegel. For other common names see below. No subspecies are currently recognized.
Take a trip through the natural world with our themed collections of video clips from the natural history archive.
Slow motion filming techniques transform amazing wildlife moments into full scale events, and simple action into incredibly detailed video sequences. | <urn:uuid:ab689a50-35eb-4b13-9901-ffc0f0f79f3a> | CC-MAIN-2013-20 | http://www.bbc.co.uk/nature/life/Bothriechis_schlegelii | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.920029 | 328 | 3.609375 | 4 |
Why does lava erupt from a volcano?
What is pyroclastic flow?
By studying volcanoes today, can scientists guess what volcanoes might have been like on Earth long ago?
How hot is the lava in a volcano?
How is magma formed?
How many volcanoes are there on our planet?
What is a caldera?
Is a volcano a mountain?
Are lava and magma the same thing?
Is there a new volcano forming in Hawaii?
How do people who live near active volcanoes adapt to their environment?
How do islands form?
What is ash?
Is the Yellowstone volcano going to explode soon?
What are supervolcanoes?
Is there is ice at the bottom of a volcano?
Can you tell me more about the Lengai volcano?
Is it true that volcanic ash can affect the climate?
Can you tell me about Krakatoa?
Can you tell me about Mount St. Helens?
What is Mount Pinatubo?
What does a volcanologist do?
What is an atoll?
When I explore a volcano, what are some tips I should follow?
How can I make a volcano for my science project?
Here are some questions about this topic.
Click the question to read the answer!
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In 1803, John Dalton of England introduced the atomic idea to chemistry (and is called the Father of Modern Atomic Theory for his efforts). However, it would be false to assume that atomic ideas disappeared completely from the intellectual map for over 2000 years. For, although atomic thinkers between the Greeks and Dalton were few, there is a fairly continuous line from the Greeks to John Dalton.
Much of the following is based on these articles:
1) "The Origins of the Atomic Theory" by J.R. Partington. Annals of Science, vol 4, no. 3 (July, 1939)
2) "The Atomic View of Matter in the XVth, XVIth, and XVIIth Centuries" by G.B. Stones. Isis, vol. 10, part 2, No. 34 (January 1928).
I. Atomism in Antiquity
The atomic ideas of Leucippus and Democritus (from about 440 BC) were opposed by Aristotle about 100 years or so later. Those who acknowledged Aristotle as their master opposed atoms. Since Epicurus was an atomist, he was opposed by his rivals, the Stoics. Cicero, Seneca and Galen all spoke against atoms.
Hero of Alexandria (150 A.D.?) makes use of atoms to explain compression and rarefaction (to thin something out; become less dense). Hero denied the existence of an extended vacuum, but allowed for a vacuum between atoms. One proof he cited was that fire could enter into a material, showing that it had openings, i.e., a vacuum. He pointed out that the pores of a diamond were too small to let in fire and so the stone was incombustible. (In the 1700's, both Lavosier and Priestly were able to burn diamonds with large lenses that concentrated the sunlight.)
Important figures within the Church spoke against atoms. Dionysios (Bishop of Alexandria 200 A.D.), Lactantius (died 324 A.D.) and Augustine (354-430 A.D.) are names cited by Partington.
II. Atomism in the Middle Ages
Isidore, Bishop of Seville (560-636), the Venerable Bede (672-735), and Hrabanus Maurus (776-856) all used the word "atom" to refer to discontunities in bodies. William of Conches (1080-1154) and Vincent of Beauvais (died ca. 1264-8) both showed knowledge of atomic thinking in their writing. William openly taught about the ideas of Democritus. Vincent wrote a great encyclopedia, but only gave short quotations about atoms.
Giles of Rome (ca. 1247-1316) taght that there are natural minima below which physical substances cannot exist. This implies an atomic theory of matter. He also investigated the nature of the vacuum using a clepsydra (a water clock) and a siphon, showing that the void exerted a force of suction.
The works of Aristotle were rediscovered by Western Europe about 1200, in Latin translations of Arabic translations from the original Greek. Much scholastic discussion followed among such people as St. Thomas Aquinas (1225-74) and Roger Bacon (1214-92). Over time, the Catholic Church began to elevate Aristotle's writings to the same level as Scripture and had associated atomic thinking with Godlessness. (Quite frankly, the ChemTeam does not know how the process took place, but it did. On a side issue, the Church also did the same thing with Ptolemy in astronomy. When Galileo opposed the Church (in the 1630's?), he was found guilty of heresy. Only recently (around the late 1980's-early 1990's) has the Church formally admitted its error.)
De Rerum Natura was rediscovered in 1417 (and printed in 1473, reprinted in 1486) and became the prime source (still true today) for the ideas of Leucippus and Democritus. You may ask how William of Conches knew of Democritus. Scattered about the libraries of churches in Europe were a few copies of De Rerum Natura. Stones, in his article, cites three known to have existed in William's lifetime. Other copies certainly also existed at that time.
III. Atomism in the Renaissance
A) Nicholas of Cusa (1401-1464) wrote:
"What dost thou understand by an atom?
"Under mental consideration that which is continuous becomes divided into the ever divisible, and the multitude of parts progresses to infinity. But by actual division we arrive at an actually indivisible part which I call an atom. For an atom is a quantity, which on account of its smallness is actually indivisible."
B) Girolamo Fracastoro (1478-1553) was a physician who wrote about atomism. In fact, the phrase "seeds of disease" is asociated with his name. In discussion the mechanism of infection, he supposed the existence of minute indivisible substances which convey the disease. he called these semina. Interestingly, Lucretius (in Book VI) refers to seeds helpful to life and seeds which cause disease and death. In a different book, Fracastoro indicates his agreement with Democritus and puts forward an atomistic point of view concerning chemical reactions.
C) Peter Ramus (1515-1572) broke with Aristotle early in his life. (Remember, the Catholic Church had long ago elevated Aristotle's works to Scripture. In essence, both were considered to be infallible.) At age 21, he presented a thesis based on this idea: "all that Aristotle has said is false." His opponents could not just appeal to the authority of Aristotle to refute him, since that would be begging the question. After attacking his ideas for a whole day and being refuted, Ramus was finally awarded his degree with honors.
In 1543, he wrote two books (aganist Aristotle) that provoked violent reaction. Their publication was banned, the books were burned, and Ramus was silenced by order of the Pope, Francis I. After the Pope died a year later, Ramus resumed teaching and was appointed professor in 1551.
However, he embraced the Reformed faith (Martin Luther had nailed his "95 Theses" to church door at the University of Wittenberg on October 31, 1517.) and was forced to flee from Paris. His home was pillaged and his library burned. He returned eventually, but ultimately died in the massacre of St. Bartholomew in Paris in 1572.
Although it appears that Ramus did not write about atomism as such, he was in the forefront of the attack on the authority of Aristotle.
D) In 1588, Giordano Bruno wrote:
"The division of natural things has a limit; an indivisible something exists. The division of natural things attains the smallest and last parts which are not perceptible by the aid of human instruments."
E) Partington lists five other names of people alive through in the 1500's and 1600's who wrote about atoms. Of interest is Sebastin Basso, who wrote of particles of the first, second, and third order, that is to say, structures BUILT UP by bringing atoms together. What we might call a molecule today. J.C. Magnenus attempted to calculate the size of an atom.
F) Daniel Sennert (1572-1637) was an atomist during the time Rene Descartes (1596-1650) and Francis Bacon (1561-1626) were alive. Both Bacon and Descartes, although intellectual giants of that era, were not too convinced about atomism.
Sennert taught that there must be atoms of more than one type and that atoms joined together to form composite bodies (I think he called these secondary atoms, but I am not sure). He used the fact that vapor from wine penetrated 4 layers of paper to show the smallness of atoms. Another example was that a large volume of vapor yielded a small drop of liquid.
He also taught that atoms retain their essential form. For example, melt some pure gold and pure silver together until completely mixed. On treating the mixture with nitric acid, the silver is dissolved and the gold remains.
G) Partington dates the real beginning of the revival of atomic thinking to the invention of the barometer in 1634 by Evangalestia Torricelli. Above the mercury of the barometer was a vacuum. An important position of Aristotle (and the Church) was that the vacuum did not exist. This invention (and the air pump by Otto von Guericke in 1654) dealt a severe, if not crippling, blow to the non-existence of the vacuum.
IV. Pierre Gassendi (1592-1655)
Gassendi is considered by many to be the reviver of atomism, but as you have seen, atomism never really went away, it was just on the fringes. However, Gassendi was successful in making atomism more widely known and acceptable, especially by separating a belief in atomism from athesism.
Before going into his teachings, it is interesting to note that in 1624, the Parliment of Paris had issued a decree that anyone holding or teaching a position opposed to Aristotle (including atomism) was liable to be put to death. Gassendi has influential friends, so he was left alone.
In 1649 he published his major work on atomism: Syntagma philosophiae Epicuri. It is divided into three sections: Logic, Physics, and Ethics.
Before even discussing atoms, Gassendi devotes three chapters to discussing the void and its necessity. He dwells on Torricelli and his experiments at length.
He describes the Greek position: atoms cannot be created nor destroyed, they are solid, they have weight, and cannot be subdivided. Gassendi taught that atoms are not just geometric points, but that they have a definite size, although it is very small.
However, he differs from the Greeks in that atoms have not been in existence forever, but were made by God. The atoms move not a se ipsis (of themselves), but Dei gratia (as a gift of God). This is the idea which freed atomism from athesism.
Gassendi allows for the union of atoms to form groups, which he calls moleculae or corpuscula. However, these groups are not held together by attractive forces, but by mechanical forces such as hooks-and-eyes or antlers.
V. From Gassendi to Dalton: Just Under 150 years
Robert Boyle (1627-91) was an atomist, although he liked the word "corpuscle." In 1661, published the "Sceptical Chymist." In it, he insists that the chemical elements must be actual, physical substances rather than the "principles" the alchemists thought of (the "principle of salt", the "principle of gold" and so on). Boyle says:
"I can easily enough sublime gold into the form of red Chrystalls of a considerable length; and many other ways may Gold be disguis'd, and help to constitute Bodies of very different Natures both from It and from one another, and nevertheless be afterwards reduc'd to the self-same Numerical, Yellow, Fixt, Ponderous, and Malleable Gold as it was before its commixture."
Later on in the book, he says of atoms (oops, sorry Bob, corpuscles) of gold:
"though they may not be primary Concretions of the most minute Particles of matter, but confessedly mixt Bodies, are able to concurre plentifully in the composition of several very differing bodies without losing their own Nature or Texture, or having their cohesion violated by the divorce of their associated parts or ingredients.
Again, he says:
"the difference of Bodies may depend meerly upon that of the schemes whereinto their Common matter is put . . . so that according as the small parts of matter reccede from each other, or work upon each other . . . a Body of this or that denomination is producd."
Incidently, two of the last non-believers in the reality of atoms were Wilhelm Ostwald and Ernst Mach. (I am not including those who are not in the mainstream of science, Ostwald and Mach were both respected scientists.) In 1908, Ostwald explicitly stated his belief in the reality of atoms in the introduction to his textbook Outline of General Chemistry. In 1915, Mach was still writing in an anti-atomistic way. The following year, Mach died, aged 78.
Since then, no one of any scientific substance has questioned the reality of atoms.
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By Robert Morningside
The Hopi believe the Creator of Man is a woman.
The Sumerians believed the Creator of Man was a woman.
The Hopi believe the Father Creator is KA.
The Sumerians believed the Father Essence was KA.
The Hopi believe Taiowa, the Sun God, is the Creator of the Earth.
The Sumerians believe TA.EA was the Creator.
The Hopi believe two brothers had guardianship of the Earth.
The Sumerians believed two brothers had dominion over the Earth.
The Hopi believe Alo to be spiritual guides.
The Sumerians believed AL.U to be beings of Heaven.
The Hopi believe Kachinas (Kat'sinas) are the spirits of nature
and the messengers and teachers sent by the Great Spirit.
The Sumerians believed KAT.SI.NA were righteous ones sent of God.
The Hopi believe Eototo is the Father of Katsinas.
The Sumerians believed EA.TA was the Father of all beings.
The Hopi believe Chakwaina is the Chief of Warriors.
The Sumerians believed TAK.AN.U was the Heavenly Destroyer.
The Hopi believe Nan-ga-Sohu is the Chasing Star Katsina.
The Sumerians believed NIN.GIR.SU to be the Master of Starships.
The Hopi believe Akush to be the Dawn Katsina.
The Sumerians believed AK.U to be Beings of light.
The Hopi believe Danik to be Guardians in the Clouds.
The Sumerians believed DAK.AN to be Sky Warriors.
The Hopi believe Sotunangu is a Sky Katsina.
The Sumerians believed TAK.AN.IKU were Sky Warriors.
The Hopi name for the Pleaides is ChooChookam.
The Sumerians believed SHU. SHU.KHEM were the supreme Stars.
The Hopi believe Tapuat is the name of Earth.
The Sumerians believed Tiamat was the name of Earth.
The Hopi call a snake Chu'a.
The Sumerians called a snake SHU.
The Hopi word for "dead" is Mokee.
The Sumerians used KI. MAH to mean "dead."
The Hopi use Omiq to mean above, up.
The Sumerians used AM.IK to mean looking to Heaven.
The Hopi believe Tuawta is One Who Sees Magic.
The Sumerians believed TUAT.U was One from the Other World.
The Hopi believe Pahana was the Lost Brother who would
one day return to assist the Hopi and humankind.
The Sumerians would recognize PA.HA.NA
as an Ancestor from heaven who would return.
In the beginning there were only two: Tawa, the Sun God, and Spider Woman (Kokyanwuhti), the Earth Goddess. All the mysteries and the powers in the Above belonged to Tawa, while Spider Woman controlled the magic of the Below.
There was neither man nor woman, bird nor beast, no living thing until these Two willed it to be.
In time they decided there should be other gods to share their labors, so Tawa divided himself and there came Muiyinwuh, God of All Life Germs and Spider Woman divided herself and there came Huzruiwuhti, Woman of the Hard Substances (turquoise, silver, coral, shell,etc.).
Huzruiwuhti became the wife of Tawa and with him produced Puukonhoya, the Youth, and Palunhoya, the Echo, and later, Hicanavaiya, Man-Eagle, Plumed Serpent and many others.
Then did Tawa and Spider Woman have the Great Thought, they would make the Earth to be between the Above and the Below. As Tawa thought the features of the Earth, Spider women formed them from clay.
Then did Tawa think of animals and beasts and plants, all the while Spider Woman formed them from the clay. At last they decided they had enough, then they made great magic and breathed life into their creatures. Now Tawa decided they should make creatures in their image to lord over all the rest. Spider Woman again formed them from clay. Again the Two breathed life into their creations. Spider Woman called all the people so created to follow where she led.
Through all the Four Great Caverns of the Underworld she led them, until they finally came to an opening, a sipapu, which led to the earth above.
Once upon a time, when our people first came up from the villages of the underworld, there was no sun. There was no moon. They saw only dreary darkness and felt the coldness. They looked hard for firewood, but in the darkness they found little.
One day as they stumbled around, they saw a light in the distance. The Chief sent a messenger to see what caused the light. As the messenger approached it, he saw a small field containing corn, beans, squash, watermelons, and other foods. All around the field a great fire was burning. Nearby stood a straight, handsome man wearing around his neck a turquoise necklace of four strands. Turquoise pendants hung from his ears.
"Who are you?" the owner of the field asked the messenger.
"My people and I have come from the cave world below," the messenger replied. "And we suffer from the lack of light and the lack of food."
"My name is Skeleton," said the owner of the field. He showed the stranger the terrible mask he often wore and then gave him some food. "Now return to your people and guide them to my field."
When all the people had arrived, Skeleton began to give them food from his field. They marvelled that, although the crops seemed so small, there was enough food for everyone. He gave them ears of corn for roasting; he gave them beans, squashes, and watermelons. The people built fires for themselves and were happy.
Later, Skeleton helped them prepare fields of their own and to make fires around them. There they planted corn and soon harvested a good crop.
"Now we should move on," the people said. "We want to find the place where we will live always."
Away from the fires it was still dark. The Great Chiefs, at a council with Skeleton, decided to make a moon like the one they had enjoyed in the underworld.
They took a piece of well-prepared buffalo hide and cut from it a great circle. They stretched the circle tightly over a wooden hoop and then painted it carefully with white paint. When it was entirely dry, they mixed some black paint and painted, all around its edge, completing the picture of the moon. When all of this was done, they attached a stick to the disk and placed it on a large square of white cloth. Thus they made a symbol of the moon.
Then the Great Chiefs selected one of the young men and bade him
to stand on top of the moon symbol. They took up the cloth by its corners and began to swing it back and forth, higher and higher. As they were swinging it, they sang a magic song. Finally, with a mighty heave, they threw the moon disk upward. It continued to fly swiftly, upward and eastward.
As the people watched, they suddenly saw light in the eastern sky. The light became brighter and brighter. Surely something was burning there, they thought. Then something bright with light rose in the east. That was the moon!
Although the moon made it possible for the people to move around with less stumbling, its light was so dim that frequently the workers in the fields would cut up their food plants instead of the weeds. It was so cold that fires had to be kept burning around the fields all the time.
Again the Great Chiefs held a council with Skeleton, and again they decided that something better must be done.
This time, instead of taking a piece of buffalo hide, they took a piece of warm cloth that they themselves had woven while they were still in the underworld. They fashioned this as they had fashioned the disk of buffalo hide, except that this time they painted the face of the circle with a copper-coloured paint.
They painted eyes and a mouth on the disk and decorated the forehead with colours that the Great Chiefs decided upon according to their desires. Around the circle, they then wove a ring of corn husks, arranged in a zig zag design. Around the circle of corn husks, they threaded a string of red hair from some animal. To the back of the disk, they fastened a small ring of corn husks. Through that ring they poked a circle of eagle feathers.
To the top of each eagle feather, the old Chief tied a few little red feathers taken from the top of the head of a small bird. On the forehead of the circle, he attached an abalone shell. Then the sun disk was completed.
Again the Great Chiefs chose a young man to stand on top of the disk, which they had placed on a large sheet. As they had done with the moon disk, they raised the cloth by holding its corners. Then they swung the sun disk back and forth, back and forth, again and again. With a mighty thrust, they threw the man and the disk far into the air. It travelled fast into the eastern sky and disappeared.
All the people watched it carefully. In a short time, they saw light in the east as if a great fire were burning. Soon the new sun rose and warmed the earth with its kindly rays.
Now with the moon to light the earth at night and the sun to light and warm it by day, all the people decided to pick up their provisions and go on. As they started, the White people took a trail that led them far to the south. The Hopis took one to the north, and the Pueblos took one midway between the two. Thus they wandered on to the places where they were to live.
The Hopis wandered a long time, building houses and planting crops until they reached the mesas where they now live. The ruins of the ancient villages are scattered to the very beginnings of the great river of the canyon--the Colorado.
When the world was new, the ancient people and the ancient creatures did not live on the top of the earth. They lived under it. All was darkness, all was blackness, above the earth as well as below it.
There were four worlds: this one on top of the earth, and below it three cave worlds, one below the other. None of the cave worlds was large enough for all the people and the creatures.
They increased so fast in the lowest cave world that they crowded it. They were poor and did not know where to turn in the blackness. When they moved, they jostled one another. The cave was filled with the filth of the people who lived in it. No one could turn to spit without spitting on another. No one could cast slime from his nose without its falling on someone else. The people filled the place with their complaints and with their expressions of disgust.
Some people said, "It is not good for us to live in this way."
"How can it be made better?" one man asked.
"Let it be tried and seen!" answered another.
Two Brothers, one older and one younger, spoke to the priest- chiefs of the people in the cave world, "Yes, let it be tried and seen. Then it shall be well. By our wills it shall be well."
The Two Brothers pierced the roofs of the caves and descended to the lowest world, where people lived. The Two Brothers sowed one plant after another, hoping that one of them would grow up to the opening through which they themselves had descended and yet would have the strength to bear the weight of men and creatures. These, the Two Brothers hoped, might climb up the plant into the second cave world. One of these plants was a cane.
At last, after many trials, the cane became so tall that it grew through the opening in the roof, and it was so strong that men could climb to its top. It was jointed so that it was like a ladder, easily ascended. Ever since then, the cane has grown in joints as we see it today along the Colorado River.
Up this cane many people and beings climbed to the second cave world. When a part of them had climbed out, they feared that that cave also would be too small. It was so dark that they could not see how large it was. So they shook the ladder and caused those who were coming up it to fall back. Then they pulled the ladder out. It is said that those who were left came out of the lowest cave later. They are our brothers west of us.
After a long time the second cave became filled with men and beings, as the first had been. Complaining and wrangling were heard as in the beginning. Again the cane was placed under the roof vent, and once more men and beings entered the upper cave world. Again, those who were slow to climb out were shaken back or left behind. Though larger, the third cave was as dark as the first and second. The Two Brothers found fire. Torches were set ablaze, and by their light men built their huts and kivas, or travelled from place to place.
While people and the beings lived in this third cave world, times of evil came to them. Women became so crazed that they neglected all things for the dance. They even forgot their babies. Wives became mixed with wives, so that husbands did not know their own from others. At that time there was no day, only night, black night. Throughout this night, women danced in the kivas (men's "clubhouses"), ceasing only to sleep. So the fathers had to be the mothers of the little ones. When these little ones cried from hunger, the fathers carried them to the kivas, where the women were dancing. Hearing their cries, the mothers came and nursed them, and then went back to their dancing. Again the fathers took care of the children.
These troubles caused people to long for the light and to seek again an escape from darkness. They climbed to the fourth world, which was this world. But it too was in darkness, for the earth was closed in by the sky, just as the cave worlds had been closed in by their roofs. Men went from their lodges and worked by the light of torches and fires. They found the tracks of only one being, the single ruler of the unpeopled world, the tracks of Corpse Demon or Death. The people tried to follow these tracks, which led eastward. But the world was damp and dark, and people did not know what to do in the darkness. The waters seemed to surround them, and the tracks seemed to lead out into the waters.
With the people were five beings that had come forth with them from the cave worlds: Spider, Vulture, Swallow, Coyote, and Locust. The people and these beings consulted together, trying to think of some way of making light. Many, many attempts were made, but without success. Spider was asked to try first. She spun a mantle of pure white cotton. It gave some light but not enough. Spider therefore became our grandmother.
Then the people obtained and prepared a very white deerskin that had not been pierced in any spot. From this they made a shield case, which they painted with turquoise paint. It shed forth such brilliant light that it lighted the whole world. It made the light from the cotton mantle look faded. So the people sent the shield-light to the east, where it became the moon.
Down in the cave world Coyote had stolen a jar that was very heavy, so very heavy that he grew weary of carrying it. He decided to leave it behind, but he was curious to see what it contained. Now that light had taken the place of darkness, he opened the jar. From it many shining fragments and sparks flew out and upward, singeing his face as they passed him. That is why the coyote has a black face to this day. The shining fragments and sparks flew up to the sky and became stars.
By these lights the people found that the world was indeed very small and surrounded by waters, which made it damp. The people appealed to Vulture for help. He spread his wings and fanned the waters, which flowed away to the east and to the west until mountains began to appear.
Across the mountains the Two Brothers cut channels. Water rushed through the channels, and wore their courses deeper and deeper. Thus the great canyons and valleys of the world were formed. The waters have kept on flowing and flowing for ages. The world has grown drier, and continues to grow drier and drier.
Now that there was light, the people easily followed the tracks of Death eastward over the new land that was appearing. Hence Death is our greatest father and master. We followed his tracks when we left the cave worlds, and he was the only being that awaited us on the great world of waters where this world is now.
Although all the water had flowed away, the people found the earth soft and damp. That is why we can see today the tracks of men and of many strange creatures between the place toward the west and the place where we came from the cave world.
Since the days of the first people, the earth has been changed to stone, and all the tracks have been preserved as they were when they were first made.
When people had followed in the tracks of Corpse Demon but a short distance, they overtook him. Among them were two little girls. One was the beautiful daughter of a great priest. The other was the child of somebody-or-other She was not beautiful, and she was jealous of the little beauty. With the aid of Corpse Demon the jealous girl caused the death of the other child. This was the first death.
When people saw that the girl slept and could not be awakened, that she grew cold and that her heart had stopped beating, her father, the great priest, grew angry.
"Who has caused my daughter to die?" he cried loudly.
But the people only looked at each other.
"I will make a ball of sacred meal," said the priest. "I will throw it into the air, and when it falls it will strike someone on the head. The one it will strike I shall know as the one whose magic and evil art have brought my tragedy upon me."
The priest made a ball of sacred flour and pollen and threw it into the air. When it fell, it struck the head of the jealous little girl, the daughter of somebody-or-other. Then the priest exclaimed, "So you have caused this thing! You have caused the death of my daughter."
He called a council of the people, and they tried the girl. They would have killed her if she had not cried for mercy and a little time. Then she begged the priest and his people to return to the hole they had all come out of and look down it.
"If you still wish to destroy me, after you have looked into the hole," she said, "I will die willingly."
So the people were persuaded to return to the hole leading from the cave world. When they looked down, they saw plains of beautiful flowers in a land of everlasting summer and fruitfulness. And they saw the beautiful little girl, the priest's daughter, wandering among the flowers. She was so happy that she paid no attention to the people. She seemed to have no desire to return to this world.
"Look!" said the girl who had caused her death. "Thus it shall be with all the children of men."
"When we die," the people said to each other, "we will return to the world we have come from. There we shall be happy. Why should we fear to die? Why should we resent death?"
So they did not kill the little girl. Her children became the powerful wizards and witches of the world, who increased in numbers as people increased. Her children still live and still have wonderful and dreadful powers.
Then the people journeyed still farther eastward. As they went, they discovered Locust in their midst.
"Where did you come from?" they asked.
"I came out with you and the other beings," he replied.
"Why did you come with us on our journey?" they asked.
"So that I might be useful," replied Locust.
But the people, thinking that he could not be useful, said to him, "You must return to the place you came from."
But Locust would not obey them. Then the people became so angry at him that they ran arrows through him, even through his heart. All the blood oozed out of his body and he died. After a long time he came to life again and ran about, looking as he had looked before, except that he was black.
The people said to one another, "Locust lives again, although we have pierced him through and through. Now he shall indeed be useful and shall journey with us. Who besides Locust has this wonderful power of renewing his life? He must possess the medicine for the renewal of the lives of others. He shall become the medicine of mortal wounds and of war."
So today the locust is at first white, as was the first locust that came forth with the ancients. Like him, the locust dies, and after he has been dead a long time, he comes to life again-- black. He is our father, too. Having his medicine, we are the greatest of men. The locust medicine still heals mortal wounds.
After the ancient people had journeyed a long distance, they became very hungry. In their hurry to get away from the lower cave world, they had forgotten to bring seed. After they had done much lamenting, the Spirit of Dew sent the Swallow back to bring the seed of corn and of other foods. When Swallow returned, the Spirit of Dew planted the seed in the ground and chanted prayers to it. Through the power of these prayers, the corn grew and ripened in a single day.
So for a long time, as the people continued their journey, they carried only enough seed for a day's planting. They depended upon the Spirit of Dew to raise for them in a single day an abundance of corn and other foods. To the Corn Clan, he gave this seed, and for a long time they were able to raise enough corn for their needs in a very short time.
But the powers of the witches and wizards made the time for raising foods grow longer and longer. Now, sometimes, our corn does not have time to grow old and ripen in the ear, and our other foods do not ripen. If it had not been for the children of the little girl whom the ancient people let live, even now we would not need to watch our cornfields whole summers through, and we would not have to carry heavy packs of food on our journeys.
As the ancient people travelled on, the children of the little girl tried their powers and caused other troubles. These mischief-makers stirred up people who had come out of the cave worlds before our ancients had come. They made war upon our ancients. The wars made it necessary for the people to build houses whenever they stopped travelling. They built their houses on high mountains reached by only one trail, or in caves with but one path leading to them, or in the sides of deep canyons. Only in such places could they sleep in peace.
Only a small number of people were able to climb up from their secret hiding places and emerge into the Fourth World. Legends reveal the Grand Canyon is where these people emerged. From there they began their search for the homes the Two Brothers intended for them.
These few were the Hopi Indians that now live on the Three Mesas of northeastern Arizona.
NATIVE AMERICAN CREATION MYTHS
NATIVE AMERICAN INDEX
CREATION BY COUNTRIES INDEX
ALPHABETICAL INDEX OF ALL FILES
CRYSTALINKS HOME PAGE
PSYCHIC READING WITH ELLIE
2012 THE ALCHEMY OF TIME | <urn:uuid:46e3a162-5b8d-4773-9f89-f60b21dd9d72> | CC-MAIN-2013-20 | http://www.crystalinks.com/hopicreation.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.985262 | 5,122 | 3.65625 | 4 |
In this back-to-school issue of Class Ideas, we're focusing on a social issue of increasing importance in today's digital world: cyberbullying. It is estimated that nearly half of children and teens have been bullied at least once via cell phone, Internet, or other digital technology. Though cyberbullying typically take place away from school, teachers and schools have a definite role to play in prevention, as this month's article points out. And to increase your understanding of cyberbullying and its dimensions, we're also offering downloadable activity pages from Didax's new grade-level series Bullying in a Cyber World, as well as a terrific special on these books and other Didax anti-bullying resources.
We hope the information you find in this issue will help you get the new school year off to a great start!
1. What is it?
According to StopCyberbullying.org, cyberbullying is "when a child, preteen or teen is tormented, threatened, harassed, humiliated, embarrassed or otherwise targeted by another child, preteen or teen using the Internet, interactive and digital technologies or mobile phones. It has to have a minor on both sides, or at least have been instigated by a minor against another minor. Once adults become involved, it is plain and simple cyber-harassment or cyberstalking. Adult cyber-harassment or cyberstalking is NEVER called cyberbullying."
2. How is it different from face-to-face bullying?
Cyberbullying involves technology, either cell phones or social networking sites or other means. It is unlike face-to-face bullying in that a child may be a cyberbully one moment and a victim the next. Children often change roles, going from victim to bully and back again.
3. What are the consequences for the children involved?
Cyberbullying can have very serious consequences. Children have been known to kill or commit suicide after being involved in a cyberbullying incident. Most of the time the cyberbullying does not go that far, although parents often attempt to pursue criminal charges. At a minimum, a child caught cyberbullying can lose his or her ISP or IM accounts as a terms-of-service violation. If hacking or password and identity theft is involved, it can be a serious criminal matter under state and federal law.
4. As a teacher, what can I look for to tell me that cyberbullying is affecting my class?
Be aware of the emotional state of your students. Does a student seem depressed? Withdrawn? Are his grades suddenly dropping? Look for changes in usual relationships, such as a student suddenly being excluded from her usual lunch table. Younger kids who are being cyberbullied may start being absent from school more often. In middle school, trouble may erupt in the back of the classroom over a cyberbullying incident the night before.
5. As a teacher, how can I deal with it?
The first step is to take it seriously, says Michelle Boykins, director of communications and marketing for the National Crime Prevention Council. "It's not just kids being kids. We have to make sure cyberbullying is not a rite of passage. If we don't change the culture, then we are helping young people be victimized."
It is important to know how to intervene when kids make social mistakes, says one bullying prevention coordinator. Let the student know that their cyberbullying behavior is wrong and guide them to another alternative. Educating students about the consequences they may incur as cyberbullies (such as losing their ISP or IM accounts) helps. Teaching them to respect others and to take a stand against bullying of all kinds helps too.
An education campaign to raise awareness among kids and teens about the consequences of cyberbullying is a second line of defense. The campaign should address ways in which students can become inadvertent cyberbullies, how to be accountable for one's actions, and the importance of not standing by and allowing bullying (in any form) to be acceptable. Students need to be taught not to ignore the pain of others.
Teaching kids to "Take five!" before responding to something they encounter online is a good place to start. Techniques to help calm down include yoga or deep breathing, running, playing catch or shooting hoops, hugging a stuffed animal, or talking on the phone with friends. If children know how to find their center again, they will often not become a cyberbully, even inadvertently. Teaching them the consequences of their actions (such as the FBI showing up at their door if a serious law is violated) helps sometimes.
Perhaps the most important thing you can do is to give children ways to avoid being victimized. Remind them to never put anything sensitive or embarassing into an electronic format and send it to someone. The more embarrassing the material is, the more likely it is to become public.
Finally, let kids know you care and will advocate for them if there is a problem. Some experts suggest having an anonymous way to report cyberbullying incidents, such as a drop box, hotline, or e-mail address. Make sure children understand that reporting cyberbullying isn't the same as tattling.
6. Why is it the school's problem?
School is the center of students' lives. Online harassment may take place during evenings or on weekends, but the fallout is often seen at school and can interfere with the educational environment. In the worst case, students are so worried about cyberbullying that they can't focus on their studies or are afraid to come to school. The problem then becomes a school climate and safety issue.
7. How can my school deal with it?
Schools can be very effective brokers in working with the parents to stop cyberbullying situations. They can also educate students about cyberethics and the law. If schools are creative, they can even handle off-campus cyberbullying without exceeding their legal authority. Experts recommend adding a provision to the school's acceptable use policy reserving the right to discipline the student for actions taken off-campus if those actions are intended to have an effect on another student or they adversely affect the safety and well-being of students while in school. This makes it a contractual, not a constitutional, issue.
Join us in October for a sneak peak at an exciting new tool for practicing and reinforcing the content from the Common Core State Standards. Common Core Collaborative Cards are an easy and effective way to group students by standard, get them talking about different approaches to the same concept, and prepare them for additional meaningful tasks in the same domain. You won't want to miss this issue of Class Ideas! | <urn:uuid:50bf3d30-bde3-44bc-9cbd-ce21a35952d4> | CC-MAIN-2013-20 | http://www.didax.com/newsletter/archive.cfm/NewsletterID/90/ad/46/src/90.cfm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.964794 | 1,367 | 3.890625 | 4 |
An oft quoted statistic says that between 70-80 percent of what people learn comes from visual stimulus. There is just something about seeing how something works that enables us to form a lasting memory of the information. As such, video is an excellent way to engage students in lessons as well as increase their retention of the subject.
For those looking to increase their use of video in education, there are almost as many ways to use video as there are videos available for use. Whether creating your own videos or using those available to you, here are a few ideas to get you started.
Demonstrate a tough to visualize concept
For concepts that really need to be seen in order for students to fully understand, videos provide a way to show students as well as tell them.
-Possible topics: famine experienced around the world, geometry, the effects of natural disasters, animals interacting in the wild
Show an experiment that cannot be done in class
Whether due to the cost of the materials needed or the danger of the experiment, there are some things that just cannot be demonstrated at school. For these occasions, video provides a way for students to experience the experiment without having to complete it themselves
-Possible uses: rocket launches, flame throwers, chemical reactions
Take students on a virtual field trip
It is not always practical to take an entire class, or school, to an off-campus location so that they can experience it. For students in rural areas, a trip to a museum may not be possible, for others, their teachers simply wants them to experience something that cannot reasonable be accomplished
-Possible uses: trips to a world-renown museum, trips to space, underwater adventures
Bring cultures from around the world to life
For many classes, understanding the way people live in other areas of the world is a large part of the curriculum. In this case, video provides a simple way to expose students to both the sights and sounds of other cultures – allow students to see how they live, what they eat, and what they wear, as well as hear what the language sounds like.
-Possible uses: video chat with a class in another country, teach a foreign language, compare vegetation around the world
Many students are already creating and sharing digital content outside the classroom. Harness their creativity and encourage them to use their skills to create a video for class.
Possible uses: video book report, teach a lesson
Become an expert
An additional benefit of using video in the classroom is that it allows teachers to shine in all subjects, not just those they are comfortable with. If someone is somewhat less knowledgeable about a particular subject they are teaching, it is possible to find a video that will explain it in a way students will understand. Video enables everyone to be an expert in every field.
With all the benefits and possibilities presented by using video in the classroom, it is a tool every teacher can and should be using. Not only does video increase retention of subject matter, video can be used to stimulate interest by creating a visual for an otherwise detached student.
What is your favorite way to use video in your class? | <urn:uuid:fd6a2a0c-ee72-4a6c-ada8-b9b347ab25e6> | CC-MAIN-2013-20 | http://www.edudemic.com/2012/11/6-simple-ways-to-use-video-in-education/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.952138 | 637 | 3.8125 | 4 |
In the United States, very old adding machines were usually (always?) built to read in dollars and cents. They required the user to pull a crank to add numbers. The numbers were input by pressing keys on a large keypad: for instance, the amount $30.72 was input using keys corresponding to "$30", "70¢", and "2¢", and then pulling the crank. Subtraction was impossible, except by adding the complement of a number (for instance, subtract $2.50 by adding $9,997.50).
A later adding machine, called the Comptometer, did not require that a crank be pulled to add. Numbers were input simply by pressing keys. The machine was thus driven by finger power.
Some adding machines were electromechanical -- an old-style mechanism, but driven by electric power.
Some "ten-key" machines had input of numbers as on a modern calculator -- 30.72 was input as "3", "0", "7", "2". These machines could subtract as well as add. Some could even multiply!
These old machines could be a royal pain to maintain and often gave wrong answers. It was probably better to learn to use an abacus.
Modern adding machines are like simple calculators. They often have a different input system, though.
|To figure out this:||Type this on the adding machine:|
|2+17+5=?||2 + 17 + 5 + T|
|19-7=?||19 + 7 - T|
|38-24+10=?||38 + 24 - 10 + T|
|7×6=?||7 × 6 =|
|18/3=?||18 ÷ 3 =|
|(1.99×3)+(.79×8)+(4.29×6)=?||1.99 × 3 = + .79 × 8 = + 4.29 × 6 = + T|
William Seward Burroughs received a patent for his adding machine in 1885. The Burroughs Adding Machine Company evolved to produce electronic billing machines and mainframes, and eventually merged with Sperry to form Unisys. The grandson of the inventor of the adding machine is Beat author William S. Burroughs (best known for Naked Lunch.)
The Adding Machine is also a 1923 expressionist play by the American playwright Elmer Rice. The play dramatizes | <urn:uuid:1a17f882-8031-4490-a97c-6790bb00bf02> | CC-MAIN-2013-20 | http://www.fact-index.com/a/ad/adding_machine.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.960364 | 509 | 3.515625 | 4 |
Ask the Experts
Group B Strep
What is Group B strep?
Your doctor is referring to a test that is routinely given to all women between weeks 35 and 37 of pregnancy. The procedure involves swabbing your vagina and rectum and examining the secretions for the presence of Group B streptococcus (GBS).
GBS is a bacterium that lives in the vagina and intestinal tract of many healthy women without causing symptoms or illness. However, the presence of GBS in the vagina during childbirth poses a risk of serious illness or death to a newborn. Babies most at risk include those whose health is compromised as a result of prematurity; a long, stressful labor; low birth weight; or illness.
About 10 to 30 percent of pregnant women test positive for GBS. If you do, you will be given intravenous antibiotics during labor to limit the risk of transmission to your baby. (If you go into premature labor and have not been screened, you also should receive antibiotics as a precaution.) This type of treatment is highly effective:98 to 99 percent of babies born to women with GBS are not affected by the bacterium. | <urn:uuid:9168577f-3326-4efe-8461-a5b2d5302c89> | CC-MAIN-2013-20 | http://www.fitpregnancy.com/pregnancy/group-b-strep | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.962385 | 238 | 3.671875 | 4 |
The faster a particle travels through vacuum, the more likely it is that the particle will interact with virtual particles contained in the vacuum. (At a quantum level, a vacuum is far from being empty.) Based on this quantum phenomena, scientists have predicted a maximum energy with which particles can travel long distances through vacuum (or the "empty space" in the universe). If the kinetic energy ("speed") of a particle exceeds this limit, the particle will eventually get involved in a collision with a virtual particle in the vacuum, creating new particles, each real and with lower kinetic energy.
Related article at http://www.europhysicsnews.org/full/12/article4/article4.html
Kurt Riesselmann, Fermilab
|last modified 12/16/2003 [email protected]| | <urn:uuid:bf3e53b2-524d-426b-9c2c-afdea229e130> | CC-MAIN-2013-20 | http://www.fnal.gov/pub/inquiring/questions/vacuum_velocity.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.855655 | 171 | 3.765625 | 4 |
When people first begin to speak, they start with nouns. That is, they name things. It is such a basic thing that it is easy to lose sight of what an intriguing and powerful thing it is to call something by "its" name.
Place names carry stories, history, culture and values. Learning the history that lies behind the familiar names of Western Canadian places is one way of learning about the people who have lived here. Every student can be charmed by the everyday names of the streets, buildings, roads and monuments that are part of their lives, and they can play a big role in helping others learn about where these names come from.
In our own community, names are not just history. Do long time members of the community know the roads, streets, buildings, and the landscape by the same names as we see on the maps today?
As we raise questions using old maps, historical documents, local histories and lore, we know that other questions, issues and debates will arise. As we pose these kinds of questions to students, we can call on what their families and neighbors know about the community. What names remain puzzles for everyone? That's where the heart of the inquiry will lie: What is there about naming that intrigued these students?
Further explanation of teacher planning, resources, assessment, curricular connections can be found at the following external link:
(There is no video for this section) | <urn:uuid:e5414cf5-4f7a-4c2a-8b39-31731fa373b9> | CC-MAIN-2013-20 | http://www.galileo.org/initiatives/ntw/davisburg/teacher-planning.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.956232 | 289 | 3.828125 | 4 |
Sclerotinia Blight -- Sclerotinia sclerotiorum
Host: More than 360 plants, including Anemone coronaria, Aquilegia spp., begonia, calceolaria, ornamental pepper, chrysanthemum, dahlia hybrids, forsythia, gerbera, petunia, Gloxinia.
Symptoms: This fungus is most damaging in outdoor soils. However, it may cause root, crown and stem rots in greenhouses. White strands of mycelium form on infected plant parts. The mycelium produces a dense mat on the surface of the soil at the base of the plant. The foliage may also become infected when the leaves come in contact with the ground. Sclerotinia are black, lumpy structures that look like charcoal.
Conditions Favoring Disease: Infection by this disease is dependent on high soil moisture for an extended period of time. Outdoors, the growing area must be at moisture field capacity for 10 days before germination will occur.
How Pathogen Survives/Disperses: The primary source of infection, resistant fungal structures called sclerotia, are found in soil and plant debris. Optimum temperatures for germination of sclerotia are 55° to 59°F. Some germination may occur over a wider temperature range — 30° to 79°F.
Photo and write up provided by Syngenta Professional Products | <urn:uuid:1ad52a6c-517d-41a4-8306-28e6f96c2471> | CC-MAIN-2013-20 | http://www.gpnmag.com/sclerotinia-blight-isclerotinia-sclerotiorumi | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.874173 | 299 | 3.515625 | 4 |
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Taken from Lessons on the Northwest Ordinance of 1787
Learning materials for secondary school courses in American history, government, and civics
by John J. Patrick
developed by the ERIC Clearinghouse for Social Studies/Social Science Education
Preview of Main Points
This lesson defines the Northwest Ordinance. Main ideas in the document are clarified and discussed. Ideas on governance and civil liberties and rights are highlighted.
This lesson is suitable for use in American history courses in junior high/middle schools and in high school courses in American history, government, and civics. Teachers of junior high/middle school students, however, might want to assign only items 1 to 3 at the end of the lesson; items 4 to 6 are more complicated and challenging. High school history and government teachers might want to have their students read the Northwest Ordinance in addition to the material for students provided in this lesson.
Students are expected to:
Suggestions for Teaching the Lesson
Opening the Lesson. Ask students to read the introduction to this lesson, which is covered in the first two paragraphs on the first page of the lesson. Then ask them if they have ever heard of the Northwest Ordinance. Poll students informally to find out what they know about this document and its significance in American history. Use this introduction to the lesson to establish the main purposes or objectives of the subsequent reading assignment.
Developing the Lesson
Have students read the entire lesson. Assign items 1 to 3 at the end of the lesson. High school teachers also might want to have students read the entire document after they read the lesson, which can serve as an introduction and overview of main ideas in the document. Teachers who choose this approach will find it convenient to make and distribute copies of the Northwest Ordinance.
Conduct a class discussion of responses to items 1 to 3 at the end of this lesson. Make use of the table in the lesson to focus attention of students on main provisions of the governance procedures in the Northwest Ordinance.
Concluding the Lesson
Teachers of eighth grade students might want to conclude the lesson with a discussion of the relative importance of different civil liberties and rights in the Northwest Ordinance.
High school teachers, and some eighth grade teachers, might conclude the lesson by assigning items 4 to 6 at the end of the lesson. Item 4 is the most complicated and challenging of these items and perhaps should be reserved for high school students only.
Teachers who assign item 6, the essay, might wish to select two or three students to read their essays to the class and to invite responses to the essays as a way of launching a class discussion about the importance of the Northwest Ordinance today and in the past. | <urn:uuid:a19524ac-33d5-4e1b-be69-b5381f7c8cc4> | CC-MAIN-2013-20 | http://www.in.gov/history/2692.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.936122 | 588 | 4.1875 | 4 |
Math Practice Online > free > lessons > Florida > 9th grade > Applied Linear Equations 2
If your child needs math practice, click here.
Applied Linear Equations 2
Creates word problems like these:
- What slope is perpendicular to slope 3/4?
- Based on equations, are the two lines parallel, perpendicular,or neither?
- Give the equation of the line that is perpendicular to y=x+3 and goes through point (3,4)
- Give the equation of the line that is parallel to y=x+3 and goes through point (3,4)
This topic aligns to the following state standards
Although this topic is important and recommended, it does not specifically align with your state's standards.
Copyright Accurate Learning Systems Corporation 2008.
MathScore is a registered trademark. | <urn:uuid:88eb3631-cb7e-41ab-950f-26ec53d3b72c> | CC-MAIN-2013-20 | http://www.mathscore.com/math/free/lessons/Florida/9th_grade/Applied_Linear_Equations_2.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.888984 | 173 | 3.640625 | 4 |
HAIR loss is one of the most distressing side effects for cancer patients undergoing chemotherapy. People are sometimes so worried about it that they don't come forward for cancer screening. But soon a cream or gel could prevent patients going bald.
Stephen Davis and his colleagues at the drugs company Glaxo Wellcome in Research Triangle Park, North Carolina, applied a drug called GW8510 to the scalps of rats before treatment with Etoposide, a common chemotherapy. Half the animals suffered no hair loss, and it was significantly reduced in the rest. Rats that didn't receive any GW8510, however, lost most of their hair. "It was just stunning," Davis says.
Most chemotherapy drugs attack rapidly dividing cells. Unfortunately, they kill not only fast-growing cancers but also healthy cells that divide rapidly, such as those surrounding the hair follicles. This is why people's hair falls out.
GW8510 works by temporarily preventing cells from ...
To continue reading this article, subscribe to receive access to all of newscientist.com, including 20 years of archive content. | <urn:uuid:bb807324-e767-429e-bd71-c304e821ffeb> | CC-MAIN-2013-20 | http://www.newscientist.com/article/mg16622342.900-keeping-up-appearances.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.974888 | 222 | 3.515625 | 4 |
Butterflies - The Heliconians
( Originally Published 1917 )
This is a tropical family with only a single species migrating northward to our Southern states. The butters flies of this group are characterized by having the wings so long and narrow that their length is usually twice as great as their width. The front legs in both sexes are so poorly developed that they are considered a modification approaching the complete dwarfing found in the Brush-footed butterflies.
The Zebra Butterfly
Heliconius Charitonius While the butterflies of temperate North America show many examples of marvelous beauty and coloring, one must go to the tropics to see the culmination of what nature has done in painting the outstretched membranes of butterfly wings with gorgeous colors. The great butterfly tribes that swarm in tropical forests seldom reach our temperate clime, and even when they do they are likely to show only a suggestion of the splendid size and rich coloring to be seen farther south. The Zebra butterfly (Heliconius charitonius) belongs to one of these tropical tribes. It shows its affinities by its coloring and the curious shape of its wings. In most of our northern butterflies, the wings are about as long as they are wide, but in the tropical family, Heliconidae, they are very much longer than wide. This gives the insect an entirely different look from our common forms so that one recognizes it at once as a stranger within our gates. Indeed, it does not penetrate far into our region, being found commonly only in Florida and one or two other neighboring states, its principal home being in tropical America.
The Zebra butterfly is well named, Across the brownish black wings there runs a series of yellow stripes, three on each front wing and one on each hind wing, with a sub-marginal row of white spots on each of the latter. The under surface is much like the upper, except that the color ing is distinctly paler. It is very variable in size: some specimens may be but two and a half inches across the expanded wings, while others are four inches.
The Zebra caterpillars feed upon the leaves of the passion flower. When full grown they are about an inch and a half long, whitish, more or less marked with brownish black spots arranged in transverse rows, and partially covered with longitudinal rows of barbed black spines.
They change to chrysalids which are remarkable for their irregular shape, with two leaf like projections on the head which the insect can move in a most curious fashion.
One of the most notable things about this insect is the fact that the male butterflies are attracted to the chrysalids of the females even before the latter emerge. Many observers have reported upon this curious phenomenon and have recorded experiments demonstrating that it is a general habit with the species.
The Roosting Habits
The adult butterflies flock together at night and rest upon the Spanish moss which festoons so many of the trees in the Far South, or upon dead branches. They take positions with heads upward and wings closed, many of them often flocking together to roost, and wandering out to the near-by fields when the morning sun gives them renewed activity. But these butterflies are essentially forest insects. Reliable observers have noticed that when one emerges from a chrysalis it flies up in the air and makes straight for the nearest woods. Others have noticed that when a butterfly in a field is alarmed it also makes for the woods. And in the regions where the species is abundant the butterflies are most likely to be found in paths and glades in the forest. Thus they show the influence of their ancestral habitat in the tropical wilderness.
There seems to be a certain amount of ceremony attending the flocking together at night for roosting purposes. A famous English naturalist, Philip Henry Gosse, saw the performance in the West Indies many years ago and described it in these words:
"Passing along a rocky foot-path on a steep wooded mountain side, in the' Parish of St. Elizabeth (Jamaica), about the end of August, 1845, my attention was attracted, just before sunset, by a swarm of these butterflies in a sort of rocky recess, overhung by trees and creepers. They were about twenty in number, and were dancing to and fro, exactly in the manner of gnats, or as Hepioli play at the side of a wood. After watching them awhile, I noticed that some of them were resting with closed wings at the extremities of one or two depending vines. One after another fluttered from the group of dancers to the re posing squadron, and alighted close to the others, so that at length, when only two or three of the fliers were left, the rest were collected in groups of half a dozen each, so close together that each group might have been grasped in the hand. When once one had alighted, it did not in general fly again, but a new-comer, fluttering at the group, seeking to find a place, sometimes disturbed one recently settled, when the wings were thrown open, and one or two flew up again. As there were no leaves on the hanging stalks, the appearance presented by these beautiful butterflies, so crowded together, their long, erect wings pointing in different directions, was not a little curious. I was told by per-sons residing near that every evening they thus assembled, and that I had not seen a third part of the numbers often collected in that spot." | <urn:uuid:679ef44f-98f3-4184-9909-3eabf30c6eae> | CC-MAIN-2013-20 | http://www.oldandsold.com/articles30/butterflies-37.shtml | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.969557 | 1,128 | 3.890625 | 4 |
Immanuel Kant (1724–1804) is one of the greatest figures in philosophy. Kant was a professor of philosophy and sciences, and eventually logic and metaphysics at the University of Königsberg.
Kant called his insights on knowledge “the Copernican revolution in philosophy” (comparing his impact on philosophy to Copernicus’ impact on astronomy). He believed that ideas can have truth independant of reality outside of our minds, that reality is known only when it conforms to the mind that holds its knowledge. According to Kant, all that which lies outside of experience is unknowable, but, contrary to the phenomenological view of German idealism that would come later, it is necessary to presume that outside things exist. Kant's view is known as transcendental idealism.
Kant also discusses the flaws in the metaphysical, that many metaphysical concepts, such as the existence of god(s) or freedom, can neither be disproven nor proven with proper reasoning alone. Kant illustrates the necessity for belief in subjective reality.
Name: Immanuel Kant
Born: April 22, 1724, Königsberg, Prussia
Died: February 12, 1804, Königsberg
Awards: Berlin Academy Prize, 1754 | <urn:uuid:1afa3fc8-1f32-4ec4-bac0-18041c479c45> | CC-MAIN-2013-20 | http://www.philosophy-index.com/kant/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.950637 | 261 | 4.1875 | 4 |
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Teacher Resources by Grade
|1st - 2nd||3rd - 4th|
|5th - 6th||7th - 8th|
|9th - 10th||11th - 12th|
A Collaboration of Sites and Sounds: Using Wikis to Catalog Protest Songs
|Grades||9 – 12|
|Lesson Plan Type||Standard Lesson|
|Estimated Time||Two 50-minute sessions|
MATERIALS AND TECHNOLOGY
- Internet access
- A recording of Kanye West's "Diamonds from Sierra Leone"
- Additional recordings of protest songs (See this List of protest songs from the Protest Songs from the Ontario Coalition Against Poverty)
- "Wiki: Don't Lose That Number" (one copy per student)
- "Make Way for Wikis" (one copy per student)
- Online Self-reflection Checklist
- Protest Song Lyrics Research Guide (three copies per student)
- Wiki Rubric
- Group Participation Assessment Sheet
- If your classroom does not have computer access, arrange for class time in the computer lab.
- Look into your administration's policies about students publishing on the Internet. Even if the rules prohibit this practice, many aspects of this lesson can be carried out off-line; the wiki component can be replaced by ideas in the Extensions section.
- Make appropriate copies of the Research Guide, "Make Way for Wikis," "Wiki: Don't Lose That Number," and Group Participation Assessment Sheet.
- Set up a wiki account with third-party server (unless you have some technical knowledge and would rather start one from scratch) such as Seedwiki or the password-protected PB Wiki.
- Visit the example wiki, and bookmark it for instructional use.
- Make copies of the Wiki Rubric for the students.
- Test the Online Self-reflection Checklist on your computers to familiarize yourself with the tool and ensure that you have the Flash plug-in installed. You can download the plug-in from the technical support page. | <urn:uuid:686865f2-063f-4f7c-ab2b-0675348756f8> | CC-MAIN-2013-20 | http://www.readwritethink.org/classroom-resources/lesson-plans/collaboration-sites-sounds-using-979.html?tab=3 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.851022 | 501 | 3.5625 | 4 |
Module 8—Introduction to Amplifiers
Pages i - ix
1-1 to 1-10
, 1-11 to 1-20
1-21 to 1-30
, 1-31 to 1-40
2-1 to 2-10
, 2-11 to 2-20
2-21 to 2-30
, 2-31 to 2-35
3-1 to 3-10
,3-11 to 3-20
3-21 to 3-30
, 3-31 to 3-40
3-41 to 3-50
, 3-51 to 3-60
3-61 to 3-70
, AI-1 to AI-3
Figure 1-9.—Direct-coupled transistor amplifiers.
Notice that the output (collector) of Q1 is connected directly to the input (base) of Q2. The network of R4, R5, and R6 is a voltage divider used to provide the bias and operating voltages for Q1 and Q2. The entire circuit provides two stages of amplification.
Direct coupling provides a good frequency response since no frequency-sensitive components (inductors and capacitors) are used. The frequency response of a circuit using direct coupling is affected only by the amplifying device itself.
Direct coupling has several disadvantages, however. The major problem is the power supply requirements for direct-coupled amplifiers. Each succeeding stage requires a higher voltage. The load and voltage divider resistors use a large amount of power and the biasing can become very complicated. In addition, it is difficult to match the impedance from stage to stage with direct coupling. (Impedance matching is covered a little later in this chapter.)
The direct-coupled amplifier is not very efficient and the losses increase as the number of stages increase. Because of the disadvantages, direct coupling is not used very often.
The most commonly used coupling in amplifiers is RC coupling. An RC-coupling network is shown in figure 1-10.
Figure 1-10.—RC-coupled transistor amplifier.
The network of R1, R2, and C1 enclosed in the dashed lines of the figure is the coupling network. You may notice that the circuitry for Q1 and Q2 is incomplete. That is intentional so that you can concentrate on the coupling network.
R1 acts as a load resistor for Q1 (the first stage) and develops the output signal of that stage. Do you remember how a capacitor reacts to ac and dc? The capacitor, C1, "blocks" the dc of Q1's collector, but "passes" the ac output signal. R2 develops this passed, or coupled, signal as the input signal to Q2 (the second stage). This arrangement allows the coupling of the signal while it isolates the biasing of each stage. This solves many of the problems associated with direct coupling.
RC coupling does have a few disadvantages. The resistors use dc power and so the amplifier has low efficiency. The capacitor tends to limit the low-frequency response of the amplifier and the amplifying device itself limits the high-frequency response. For audio amplifiers this is usually not a problem; techniques for overcoming these frequency limitations will be covered later in this module.
Before you move on to the next type of coupling, consider the capacitor in the RC coupling. You probably remember that capacitive reactance (X C) is determined by the following formula:
This explains why the low frequencies are limited by the capacitor. As frequency decreases, XC increases. This causes more of the signal to be "lost" in the capacitor.
The formula for XC also shows that the value of capacitance (C) should be relatively high so that capacitive reactance (XC) can be kept as low as possible. So, when a capacitor is used as a coupling element, the capacitance should be relatively high so that it will couple the entire signal well and not reduce or distort the signal.
Impedance coupling is very similar to RC coupling. The difference is the use of an impedance device
(a coil) to replace the load resistor of the first stage.
Figure 1-11 shows an impedance-coupling network between two stages of amplification. L1 is the load for Q1 and develops the output signal of the first stage. Since the d.c. resistance of a coil is low, the efficiency of the amplifier stage is increased. The amount of signal developed in the output of the stage depends on the inductive reactance of L1. Remember the formula for inductive reactance:
Figure 1-11.—Impedance-coupled transistor amplifier.
The formula shows that for inductive reactance to be large, either inductance or frequency or both must be high. Therefore, load inductors should have relatively large amounts of inductance and are most effective at high frequencies. This explains why impedance coupling is usually not used for audio amplifiers.
The rest of the coupling network (C1 and R1) functions just as their counterparts (C1 and R2) in the RC-coupling network. C1 couples the signal between stages while blocking the d.c. and R1 develops the input signal to the second stage (Q2).
Figure 1-12 shows a transformer-coupling network between two stages of amplification. The transformer action of T1 couples the signal from the first stage to the second stage. In figure 1-12, the primary of T1 acts as the load for the first stage (Q1) and the secondary of T1 acts as the developing impedance for the second stage (Q2). No capacitor is needed because transformer action couples the signal between the primary and secondary of T1.
Figure 1-12.—Transformer-coupled transistor amplifier.
The inductors that make up the primary and secondary of the transformer have very little dc resistance, so the efficiency of the amplifiers is very high. Transformer coupling is very often used for the final output (between the final amplifier stage and the output device) because of the impedance-matching qualities of the transformer. The frequency response of transformer-coupled amplifiers is limited by the inductive reactance of the transformer just as it was limited in impedance coupling.
Q-12. What is the purpose of an amplifier-coupling network? Q-13. What are four methods of coupling amplifier stages?
Q-14. What is the most common form of coupling?
Q-15. What type coupling is usually used to couple the output from a power amplifier?
Q-16. What type coupling would be most useful for an audio amplifier between the first and second stages?
Q-17. What type of coupling is most effective at high frequencies?
IMPEDANCE CONSIDERATIONS FOR AMPLIFIERS
It has been mentioned that efficiency and impedance are important in amplifiers. The reasons for this may not be too clear. You have been shown that any amplifier is a current-control device. Now there are two other principles you should try to keep in mind. First, there is no such thing as "something for nothing" in electronics. That means every time you do something to a signal it costs something. It might mean a loss in fidelity to get high power. Some other compromise might also be made when a circuit is designed. Regardless of the compromise, every stage will require and use power. This brings up the second principle-do things as efficiently as possible. The improvement and design of electronic circuits is an attempt to do things as cheaply as possible, in terms of power, when all the other requirements (fidelity, power output, frequency range, etc.) have been met.
This brings us to efficiency. The most efficient device is the one that does the job with the least loss of power. One of the largest losses of power is caused by impedance differences between the output of one circuit and the input of the next circuit. Perhaps the best way to think of an impedance difference (mismatch) between circuits is to think of different-sized water pipes. If you try to connect a one-inch water pipe to a two-inch water pipe without an adapter you will lose water. You must use an adapter. An
impedance-matching device is like that adapter. It allows the connection of two devices with different impedances without the loss of power.
Figure 1-13 shows two circuits connected together. Circuit number 1 can be considered as an a.c. source (ES) whose output impedance is represented by a resistor (R1). It can be considered as an a.c. source because the output signal is an a.c. voltage and comes from circuit number 1 through the output impedance. The input impedance of circuit number 2 is represented by a resistor in series with the source. The resistance is shown as variable to show what will happen as the input impedance of circuit number 2 is changed.
Figure 1-13.—Effect of impedance matching in the coupling of two circuits.
The chart below the circuit shows the effect of a change in the input impedance of circuit number 2 (R2) on current (I), signal voltage developed at the input of circuit number 2 (ER2), the power at the output of circuit number 1 (PR1), and the power at the input to circuit number 2 (PR2).
Two important facts are brought out in this chart. First, the power at the input to circuit number 2 is greatest when the impedances are equal (matched). The power is also equal at the output of circuit number 1 and the input of circuit number 2 when the impedance is matched. The second fact is that the largest voltage signal is developed at the input to circuit number 2 when its input impedance is much larger than the output impedance of circuit number 1. However, the power at the input of circuit number 2
is very low under these conditions. So you must decide what conditions you want in coupling two circuits together and select the components appropriately.
Two important points to remember about impedance matching are as follows. (1) Maximum power transfer requires matched impedance. (2) To get maximum voltage at the input of a circuit requires an intentional impedance mismatch with the circuit that is providing the input signal.
Impedance Characteristics of Amplifier Configurations
Now that you have seen the importance of impedance matching the stages in an electronic device, you may wonder what impedance characteristics an amplifier has. The input and output impedances of a transistor amplifier depend upon the configuration of the transistor. In Module 7, Introduction to
Solid-State Devices and Power Supplies, you were introduced to the three transistor configurations; the common emitter, the common base, and the common collector. Examples of these configurations and their impedance characteristics are shown in figure 1-14.
Figure 1-14.—Transistor amplifier configurations and their impedance characteristics.
NOTE: Only approximate impedance values are shown. This is because the exact impedance values will vary from circuit to circuit. The impedance of any particular circuit depends upon the device (transistor) and the other circuit components. The value of impedance can be computed by dividing the signal voltage by the signal current. Therefore:
The common-emitter configuration provides a medium input impedance and a medium output impedance. The common-base configuration provides a low input impedance and a high output impedance. The common-collector configuration provides a high input impedance and a low output impedance. The common-collector configuration is often used to provide impedance matching between a high output impedance and a low input impedance.
If the amplifier stage is transformer coupled, the turns ratio of the transformer can be selected to provide impedance matching. In NEETS Module 2, Introduction to Alternating Current and Transformers, you were shown the relationship between the turns ratio and the impedance ratio in a transformer. The relationship is expressed in the following formula:
As you can see, impedance matching between stages can be accomplished by a combination of the amplifier configuration and the components used in the amplifier circuit.
Q-18. What impedance relationship between the output of one circuit and the input of another circuit will provide the maximum power transfer?
Q-19. If maximum current is desired at the input to a circuit, should the input impedance of that circuit be lower than, equal to, or higher than the output impedance of the previous stage?
Q-20. What are the input- and output-impedance characteristics of the three transistor configurations?
& Q-21. What transistor circuit configuration should be used to match a high output impedance to a low input impedance?
Q-22. What type of coupling is most useful for impedance matching?
Perhaps you have been around a public address system when a squeal or high-pitched noise has come from the speaker. Someone will turn down the volume and the noise will stop. That noise is an indication that the amplifier (at least one stage of amplification) has begun oscillating. Oscillation is covered in detail in NEETS Module 9, Introduction to Wave-Generation and Wave-Shaping Circuits. For now, you need only realize that the oscillation is caused by a small part of the signal from the amplifier output being sent back to the input of the amplifier. This signal is amplified and again sent back to the input where it is amplified again. This process continues and the result is a loud noise out of the speaker. The process of sending part of the output signal of an amplifier back to the input of the amplifier is called FEEDBACK.
There are two types of feedback in amplifiers. They are POSITIVE FEEDBACK, also called REGENERATIVE FEEDBACK, and NEGATIVE FEEDBACK, also called DEGENERATIVE FEEDBACK. The difference between these two types is whether the feedback signal is in phase or out of phase with the input signal.
Positive feedback occurs when the feedback signal is in phase with the input signal. Figure 1-15 shows a block diagram of an amplifier with positive feedback. Notice that the feedback signal is in phase with the input signal. This means that the feedback signal will add to or "regenerate" the input signal. The result is a larger amplitude output signal than would occur without the feedback. This type of feedback is what causes the public address system to squeal as described above.
Figure 1-15.—Positive feedback in an amplifier.
Figure 1-16 is a block diagram of an amplifier with negative feedback. In this case, the feedback signal is out of phase with the input signal. This means that the feedback signal will subtract from or "degenerate" the input signal. This results in a lower amplitude output signal than would occur without the feedback.
Figure 1-16.—Negative feedback in an amplifier.
Sometimes feedback that is not desired occurs in an amplifier. This happens at high frequencies and limits the high-frequency response of an amplifier. Unwanted feedback also occurs as the result of some circuit components used in the biasing or coupling network. The usual solution to unwanted feedback is a feedback network of the opposite type. For example, a positive feedback network would counteract unwanted, negative feedback.
Feedback is also used to get the ideal input signal. Normally, the maximum output signal is desired from an amplifier. The amount of the output signal from an amplifier is dependent on the amount of the input signal. However, if the input signal is too large, the amplifying device will be saturated and/or cut off during part of the input signal. This causes the output signal to be distorted and reduces the fidelity of the amplifier. Amplifiers must provide the proper balance of gain and fidelity.
Figure 1-17 shows the way in which feedback can be used to provide the maximum output signal without a loss in fidelity. In view A, an amplifier has good fidelity, but less gain than it could have. By adding some positive feedback, as in view B, the gain of the stage is increased. In view C, an amplifier has so much gain and such a large input signal that the output signal is distorted. This distortion is caused by the amplifying device becoming saturated and cutoff. By adding a negative feedback system, as in view D, the gain of the stage is decreased and the fidelity of the output signal improved.
Figure 1-17A.-Feedback uses in amplifiers.
Figure 1-17B.—Feedback uses in amplifiers.
Figure 1-17C.—Feedback uses in amplifiers.
Figure 1-17D.—Feedback uses in amplifiers.
Positive and negative feedback are accomplished in many ways, depending on the reasons requiring the feedback. A few of the effects and methods of accomplishing feedback are presented next.
As you have seen, positive feedback is accomplished by adding part of the output signal in phase with the input signal. In a common-base transistor amplifier, it is fairly simple to provide positive feedback. Since the input and output signals are in phase, you need only couple part of the output signal back to the input. This is shown in figure 1-18.
Introduction to Matter, Energy, and Direct Current,
to Alternating Current and Transformers, Introduction to Circuit Protection,
Control, and Measurement
, Introduction to Electrical Conductors, Wiring Techniques,
and Schematic Reading
, Introduction to Generators and Motors
Introduction to Electronic Emission, Tubes, and Power Supplies,
Introduction to Solid-State Devices and Power Supplies
Introduction to Amplifiers, Introduction to
Wave-Generation and Wave-Shaping Circuits
, Introduction to Wave Propagation, Transmission
Lines, and Antennas
, Microwave Principles,
, Introduction to Number Systems and Logic Circuits, Introduction
to Microelectronics, Principles of Synchros, Servos, and Gyros
Introduction to Test Equipment
, Radar Principles,
The Technician's Handbook,
Master Glossary, Test Methods and Practices,
Introduction to Digital Computers,
Magnetic Recording, Introduction to Fiber Optics | <urn:uuid:07ed37e7-0640-47f5-9d57-cf23089c8269> | CC-MAIN-2013-20 | http://www.rfcafe.com/references/electrical/NEETS%20Modules/NEETS-Module-08-1-11-1-20.htm | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.906177 | 3,728 | 3.90625 | 4 |
Back in the 1950s astronomers discovered a strange population of stars on the lam. Known as OB runaways, these massive stars tear through space at surprisingly high speed—sometimes hundreds of kilometers per second.
How they got going so fast is an open question. It's been proposed that other, exploding stars could be the reason. A supernova, after all, packs enough punch to launch a neighboring star outward at high speed. But a new study published online by the journal Science supports an alternative idea. [Michiko S. Fujii and Simon Portegies Zwart, "The Origin of OB Runaway Stars"]
The mechanism involves a bully binary—that's the astronomers' actual language. The bully is a pair of supersize stars orbiting each other within a larger star cluster. If a third star ventures too close, the bully binary flings it clear like a slingshot. Voila! A runaway. According to the new study, bully binaries form naturally and can each fling out dozens of runaways. And the number of massive stars ejected this way matches up well with actual observations of OB runaways.
So who can blame the runaway stars for fleeing an unfair fight? As it's been said: "Discretion is the better part of valor."
[The above text is a transcript of this podcast.] | <urn:uuid:46fe2d0a-6a49-4d97-851b-81d9e7d55644> | CC-MAIN-2013-20 | http://www.scientificamerican.com/podcast/episode.cfm?id=runaway-stars-may-be-fleeing-bigger-11-11-21 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.900583 | 271 | 3.5625 | 4 |
As we begin our journey into Common Core, we need a way to keep our standards organized. I put together some pages that you can use in a 3-ring binder, folder, or whatever you choose. You can use these pages to organize, record information, or help you map out the science standards and list how you plan to meet them. I plan to write how I am meeting that standard in the text box below the standard. We have been told that the wording on the science standards may change, but the content will not. If the wording changes, I will revise these and send out a new copy! I hope these pages help you in our journey into Common Core! *These are not lesson plans* This product is the Science CCSS laid out in a format that will allow you to plan. We just want to make sure there isn't any confusion!! Thank you!!
*We added a checklist so you can track your students' progress through these standards!*
Text by Kevin and Amanda; Graphics by www.scrappindoodles.com
I'm sorry that our description and thumbnails did not give you a clear idea as to what this product might be. I'm not sure what you thought you were purchasing, but we are sorry it is not what you expected.
October 1, 2012
This was good information as we're switching to common core english and math this year.
Thanks for being proactive in creating this document. It allows teachers to start gathering resources to meet these new standards that will be required curriculum in the future. When I was having printing problems (not their fault), Brittany was quick to respond to my questions. She went above and beyond what most people might expect in a speedy fashion. Teachers provide such great support for each other!
Just the individual standards. That is a good idea though. We will work on that and hopefully have it added soon. If it's something you would like, leave your e-mail and when we add it. Are you looking for a spreadsheet so you can check off when the standard has been mastered?
Hello, I just purchased your product and printed out the 3 pictures for the science strands to create a science notebook for my students. Unfortunately, the patterns and cycles picture keeps printing with a black ink streak under the word cycles and from the clouds across to the side of the page. It happened both times I printed it. It does not show that in the picture. Can you help me get this from happening? Love your product!
Thank you! Have you tried opening it in Adobe Reader? Are you opening it on a Mac? Sometimes that will cause problems. If nothing else works I'd be happy to e-mail you a copy! Just send me your e-mail! | <urn:uuid:375e219f-7e38-44c3-9deb-c6e0734bebf8> | CC-MAIN-2013-20 | http://www.teacherspayteachers.com/Product/Science-First-Grade-Common-Core-251384 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.954873 | 562 | 3.5625 | 4 |
Astronomers have found hints of a massive, distant, still unseen object at the edge of the solar system. It could be a 10th planet or perhaps a failed companion star, and has an orbit that is 3 trillion miles away.
Two teams of scientists, from England and the University of Louisiana, independently report this conclusion based on the highly elliptical orbits of comets that originate from an icy cloud of debris far beyond Pluto. ?We were driven to this by rejecting everything else we could think of,? says University of Louisiana physicist Daniel Whitmire.
A couple years ago, Whitmire, along fellow physicists John Matese and Patrick Whitman, noticed the farthest points of the comets? orbits didn?t appear random but were bunched together. ?We accidentally noticed they weren?t uniform,? Whitmire says.
They tried to explain the clumping as the gravitational pull from some stars in the Milky Way. ?That ultimately didn?t work,? Whitmire says. ?We?ve gone through several other models trying to explain this.?
At the same time, John Murray, a planetary scientist at The Open University in Great Britain, made a similar observation about comets. ?I started puzzling what this might could be,? he says.
The most obvious but seemingly unlikely explanation would be a planet. ?I thought we?d better rule that out,? he says. But as he analyzed the orbits, the farthest points appeared to fall on a circular orbital path ? ?which is exactly what you would expect if there was a planet out there.?
The planet is estimated to have a mass as large as one to10 Jupiters. As it orbits, its gravitational wake disturbs the icy debris of the outer solar system, causing some of it to plunge toward the sun as comets. No one has yet directly observed a 10th planet, and there could be another cause for the cluster of comets. Both Murray and the University of Louisiana physicists put the planet in an orbit about 3 trillion miles, or half a light year, from the sun. The nearest star is four light-years away. In a scaled-down version of the solar system, if the Earth is one inch from the sun, Pluto, the ninth planet, would be about a yard from the sun. The new planet would be a half-mile away from the sun.
At that distance, the 10th planet is be too dim to be seen by telescopes, although there is some hope that if it exists, the next generation of space-based infrared telescopes might be able to observe it.
Murray thinks the planet may have been wandering through the galaxy before being captured by our solar system?s gravity. Whitmire suggests it?s a ?brown dwarf,? or a failed star, a companion to the sun.
?It?s possibly suggestive,? says Brian Marsden, associate director for planetary sciences at the Harvard-Smithsonian Center for Astrophysics. ?I don?t want to bet on it. We?re certainly not going to name it.?
Whitmire says, ?Until it?s found, you can never be overly confident. We know in science you can be fooled by statistics.? He adds, ?If I was betting, it?s better than 50-50 odds that it?s there.?
To learn more, read ?Dark Matter, Missing Planets & New Comets? by Tom van Flandern,click here.
NOTE: This news story, previously published on our old site, will have any links removed. | <urn:uuid:f142a29f-09b8-4a88-a84d-ff6ade74d372> | CC-MAIN-2013-20 | http://www.unknowncountry.com/news/does-planet-x-exist | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.963464 | 732 | 3.59375 | 4 |
According to the UN Intergovernmental Panel on Climate Change, climate change models suggest that average global temperatures will likely rise by 2 to 11.5 degrees F (1.1 to 6.4 degrees C) by the end of this century. The consequences of an increase of just a few degrees are dire. Apparently, taking clear and effective steps to reduce global warming, like cutting down carbon emissions and stimulating carbon absorption, are almost impossible in today’s politically inept world, and instead we ought to seek salvation in SciFi project in space. The latest such audacious idea comes from Scottish scientists who suggest that a massive dust cloud spewed away from a neighboring asteroid, just at the right distance away from Earth and concentration, could filter away some of the sun’s radiation and cool the planet down.
It’s not like this is the craziest anti-global warming scientific project we’ve ever heard, though. There have been many voices advocating geoengineering, massive engineering projects with a global scale impact, as a solution for today’s shaken climate, and the tomorrow’s uncertain future. Geo-engineering plankton blooms, via marine iron fertilization, are said to absorb some of the excess carbon dioxide we’ve emitted into the atmosphere. Another idea is to place some huge pipes in oceanic depths, in order to bring the nutrient-rich waters from the ocean floor to the surface where they might mix and stimulate the growth of those algae blooms. Or, just what might be the craziest one yet, deploying a giant mirror in space as a means of reflecting the sun’s radiation. A mirror just as this, or a set of connecting mirrors, would have to be huge in order to disperse enough radiation for the project to become feasible – yet mankind has been toiling away for the past decade to build a tiny space station. Seeing how the cost per pound for space launches is in the thousands of dollars range, this sounds plain wrong.
Having in mind just these past few examples of geoengineering, deploying a giant dust cloud, kept in position by an asteroid’s gravity, in order to shade the Earth might not sound that preposterous … or does it? A similar idea has been proposed in past, in the form of a simple dust cloud which could block the sun’s radiation, however the risk of getting dispersed by the gravitational pull of the sun, moon and planets is too great to work. The gravitational pull of an asteroid, though, would lock such a cloud dust in position and make the idea work, in theory at least .
“I would like to make it clear that I would never suggest geoengineering in place of reducing our carbon emissions,” said Russell Bewick, a space scientist at the University of Strathclyde in Scotland. Instead, he said, “We can buy time to find a lasting solution to combat Earth’s climate change. The dust cloud is not a permanent cure, but it could offset the effects of climate change for a given time to allow slow-acting measures like carbon capture to take effect.”
The key lies in canceling out external gravitational pull. In a sort of gravitational tug-of-war, lies a point where the sun and Earth’s gravitation cancel themselves out – this is called the Lagrange point L1, located at around four times the distance from the Earth to the moon.
The researchers calculate that the largest near-Earth asteroid, 1036 Ganymed, could maintain a dust cloud large enough to block out 6.58 percent of the solar radiation that would normally reach Earth, more than enough to combat any current global warming trends. The asteroid, once in place, would be fitted with a “mass driver,” a kind of electromagnetic catapult that would provide the power both to move the asteroid into position and to blast the cloud of dust, once created, from its surface.
Not that simple, as you might imagine
“The company Planetary Resources recently announced their intention to mine asteroids,” Bewick said. “The study that they base their plans on reckons that it will be possible to capture an asteroid with a mass of 500,000 kilograms (1.1 million lbs.) by 2025. Comparing this to the mass of Ganymed makes the task of capturing it seem unfeasible, at least in everything except the very far term. However, smaller asteroids could be moved and clustered at the first Lagrange point.”
“A very large asteroid is a potential threat to Earth, and therefore great care and testing would be required in the implementation of this scenario,” Bewick said. “Due to this, the political challenges would probably match the scale of the engineering challenge. Even for the capture of much smaller asteroids, there will likely be reservations from all areas of society, though the risks would be much less.”
Add the current economical, political and the simple fact that the world simply can not be mobilized towards a common, global goal in today’s society and leaders’ philosophy, to the slew of challenges revolving around the project.
Scientists will detail their findings in the Nov. 12 edition of the journal Advances in Space Research. | <urn:uuid:2f364e2e-f0b3-4327-9eb6-767eeda5a710> | CC-MAIN-2013-20 | http://www.zmescience.com/ecology/environmental-issues/reducing-global-warming-asteroid-9312323/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368707184996/warc/CC-MAIN-20130516122624-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.947911 | 1,081 | 3.703125 | 4 |
The first volume of the New England Journal of Medicine and Surgery, and the Collateral Branches of Science, published in 1812, gives a sense of the constraints faced by surgeons, and the mettle required of patients, in the era before anesthesia and antisepsis. In the April issue for that year, John Collins Warren, surgeon at the Massachusetts General Hospital and son of one of the founders of Harvard Medical School, published a case report describing a new approach to the treatment of cataracts.1 Until that time, the prevalent method of cataract treatment was “couching,” a procedure that involved inserting a curved needle into the orbit and using it to push the clouded lens back and out of the line of sight.2 Warren’s patient had undergone six such attempts without lasting success and was now blind. Warren undertook a more radical and invasive procedure — actual removal of the left cataract. He described the operation, performed before the students of Harvard Medical School.
Click the pic to read this fascinating history. | <urn:uuid:7633d78c-396e-4691-b770-18c9054e09c5> | CC-MAIN-2013-20 | http://apowl.com/two-hundred-years-of-surgery/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.951565 | 213 | 3.53125 | 4 |
Pathophysiology of Diarrhea
Diarrhea is an increase in the volume of stool or frequency of defecation. It is one of the most common clinical signs of gastrointestinal disease, but also can reflect primary disorders outside of the digestive system. Certainly, disorders affecting either the small or large bowel can lead to diarrhea.
For many people, diarrhea represents an occasional inconvenience or annoyance, yet at least 2 million people in the world, mostly children, die from the consequences of diarrhea each year.
There are numerous causes of diarrhea, but in almost all cases, this disorder is a manifestation of one of the four basic mechanisms described below. It is also common for more than one of the four mechanisms to be involved in the pathogenesis of a given case.
Absorption of water in the intestines is dependent on adequate absorption of solutes. If excessive amounts of solutes are retained in the intestinal lumen, water will not be absorbed and diarrhea will result. Osmotic diarrhea typically results from one of two situations:
A distinguishing feature of osmotic diarrhea is that it stops after the patient is fasted or stops consuming the poorly absorbed solute.
Large volumes of water are normally secreted into the small intestinal lumen, but a large majority of this water is efficienty absorbed before reaching the large intestine. Diarrhea occurs when secretion of water into the intestinal lumen exceeds absorption.
Many millions of people have died of the secretory diarrhea associated with cholera. The responsible organism, Vibrio cholerae, produces cholera toxin, which strongly activates adenylyl cyclase, causing a prolonged increase in intracellular concentration of cyclic AMP within crypt enterocytes. This change results in prolonged opening of the chloride channels that are instrumental in secretion of water from the crypts, allowing uncontrolled secretion of water. Additionally, cholera toxin affects the enteric nervous system, resulting in an independent stimulus of secretion.
Exposure to toxins from several other types of bacteria (e.g. E. coli heat-labile toxin) induce the same series of steps and massive secretory diarrhea that is often lethal unless the person or animal is aggressively treated to maintain hydration.
In addition to bacterial toxins, a large number of other agents can induce secretory diarrhea by turning on the intestinal secretory machinery, including:
In most cases, secretory diarrheas will not resolve during a 2-3 day fast.
Inflammatory and Infectious Diarrhea
The epithelium of the digestive tube is protected from insult by a number of mechanisms constituting the gastrointestinal barrier, but like many barriers, it can be breached. Disruption of the epithelium of the intestine due to microbial or viral pathogens is a very common cause of diarrhea in all species. Destruction of the epithelium results not only in exudation of serum and blood into the lumen but often is associated with widespread destruction of absorptive epithelium. In such cases, absorption of water occurs very inefficiently and diarrhea results. Examples of pathogens frequently associated with infectious diarrhea include:
The immune response to inflammatory conditions in the bowel contributes substantively to development of diarrhea. Activation of white blood cells leads them to secrete inflammatory mediators and cytokines which can stimulate secretion, in effect imposing a secretory component on top of an inflammatory diarrhea. Reactive oxygen species from leukocytes can damage or kill intestinal epithelial cells, which are replaced with immature cells that typically are deficient in the brush border enyzmes and transporters necessary for absorption of nutrients and water. In this way, components of an osmotic (malabsorption) diarrhea are added to the problem.
Diarrhea Associated with Deranged Motility
In order for nutrients and water to be efficiently absorbed, the intestinal contents must be adequately exposed to the mucosal epithelium and retained long enough to allow absorption. Disorders in motility than accelerate transit time could decrease absorption, resulting in diarrhea even if the absorptive process per se was proceeding properly.
Alterations in intestinal motility (usually increased propulsion) are observed in many types of diarrhea. What is not usally clear, and very difficult to demonstrate, is whether primary alterations in motility are actually the cause of diarrhea or simply an effect.
|Index of: The Small Intestine: Introduction and Index|
Last updated on July 27, 2006
|Author: R. Bowen|
|Send comments via form or email to [email protected]| | <urn:uuid:f1330f6d-a32d-4153-877e-76df287cdb88> | CC-MAIN-2013-20 | http://arbl.cvmbs.colostate.edu/hbooks/pathphys/digestion/smallgut/diarrhea.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.922782 | 927 | 3.734375 | 4 |
GRE Math Trick: Ratio Tables
When a GRE quantitative problem features multiple ratios, many of you suffer headaches. This is because the “math” way of solving the problem is brutal, and students who don’t use logic will dive head-first into a morass of ugly substitutions, mistakenly assuming that the GRE is a math test. Here’s the kind of problem I’m talking about:
In a particular mixed candy bag, the ratio of Skittles to M&M’s is 4 to 5, while the ratio of Reese’s Pieces to M&M’s is 9 to 7. What is the ratio of Skittles to Reese’s Pieces?
The “math” way to do this problem is to set up two equations, solve one for M&M’s, and plug that value into the other one. If that sounds painful, that’s because it is. Don’t do this. Make a simple table instead:
S | M | R
4 : 5
7 : 9
Take a moment to confirm that you understand where the numbers above are coming from. They’re just a translation of the information in the word problem.
The question asks for the ratio of S to R. Can you just say it’s 4 to 9? No way. The value connecting them — the M — is different. It’s 5 in one ratio and 7 in the other. So, rewrite the ratios to make the M term the same in both, creating a kind of “bridge.”
Multiply the first ratio by 7: 7×(4:5) = 28:35
Multiply the second ratio by 5: 5×(7:9) = 35:45
Next, check out your new table:
S | M | R
28 : 35
35 : 45
Now you can just “walk across the bridge,” as it were — the ratio of S to R is simply 28:45. Try this technique on your next multiple-ratios problem and let us know how it goes! | <urn:uuid:823cfeaa-1b36-4c9a-a3cb-b54cf71afbb0> | CC-MAIN-2013-20 | http://blog.kaplangradprep.com/2013/03/06/gre-math-trick-ratio-tables/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.916631 | 450 | 3.578125 | 4 |
Easter/Empty Tomb- (Pre K – K) lesson plan with: Objectives, Word Wall, Bible Story with questions, Songs and/or Finger Plays, Activities, Crafts, Games, Snacks, Coloring/Puzzles
Easter/Empty Tomb- lesson plan for 1st grade on up with: Objectives, Review, Vocabulary Words, Bible Story with questions, Activities, Crafts, Games, Snacks, Puzzles/Mazes/Worksheets
avemariapress.com- Easter/Resurrection Lesson Plan: Compare and Contrast the Gospel Accounts of the Resurrection
sundayschoolsources.com- Jesus' Burial and Resurrection lesson with discussions, songs, crafts, games, questions, worksheets, memory work, etc.
Roll the Stone Away
Two Angles in White
lessons with puzzles, coloring sheet, Bible readings, questions, memory verses, key points, object lesson, drama, puppets, etc. (These files are set up and formatted so that they can be easily made into weekly booklets for your children's ministry, youth ministry, etc., with 4 sheets of legal paper and two staples).
mssscrafts.com- The Resurrection with tons of resources for illustrating the story, coloring pages/activity sheets, crafts, and songs.
dltk-bible.com- Jesus is Alive! lesson with introduction, message, welcome, craft/baking time, Bible story time, and closing.
calvarycurriculum.com- Jesus is Risen! #238 lesson with memory verses, circle the correct words, true or false, fill in the blanks, puzzles, and color sheets.
calvarycurriculum.com- Peter & John Visit Jesus' Tomb lesson #239 with memory verses, circle the correct words, true or false, fill in the blanks, puzzles, and color sheets.
thereligionteacher.com- Catholic Easter Activities
lambsongs.co.nz- Easter booklets and coloring books (in color or black and white)
sermons4kids.com- He’s Alive
lambsongs.co.nz- 5 booklets to print out for the children to color
Easter Lapbooks- Make an Easter lapbook to celebrate the Easter season.
Introduce craft: Did they find Jesus in the tomb on Easter? Let’s make something that shows what they found.
The Empty Tomb- A cute craft that the children will get to "roll the stone away" on Jesus' tomb to retell the story of the resurrection. (Preschool Christian Crafts by Linda Standke, page 57 & 58).
Resurrection Story Wheel- Children turn their story wheel dials to retell the Bible story they learned over and over again. (Preschool Christian Crafts by Linda Standke. Directions on page 37 - 39, craft template on page 40 & 42.)
Easter- Bible Story Wheel (Bible Wheels to Make and Enjoy by Carmen Sorvillo, page 57 & 58.)
catholicicing.com- Printable Resurrection Set
Introduce craft: Who died for our sins and rose again on the third day?
annieshomepage.com- Jelly Bean Prayer
Prayer with activities to go with it: cards and jar craft
kinderart.com- Jelly Bean Sweet Jar (craft)
mama-jean.blogspot.com- Jelly Bean Prayer label (printable)
churchhousecollection.blogspot.com- Jelly Bean Prayer Toilet Paper Roll Craft For Easter
Introduce craft: Remember the caterpillar we made at Lent? We made a caterpillar to remind us that we are to change during Lent and become more like Jesus. Now the caterpillar has changed. What did he change into? A butterfly. Let’s have our caterpillars change into a butterfly.
Butterfly- A butterfly is made from using the child's handprints. The butterfly represents how the caterpillar changed and became a butterfly and received new life. (From the Hands of a Child by Anthony Flores, page 40).
crafts.kaboose.com- Coffee Filter Butterfly
Make a beautiful butterfly using a coffee filter.
freepreschoolcrafts.com- Plastic Bag Butterfly
Make this butterfly according to the directions or use a painted clothes pin for the body that has googly eyes glued on it. Gather the plastic bag together at the center and slide it between the clamps of the clothes pin. Shape some pipe cleaner into antennae and glue the center of the pipe cleaner between the clamps of the clothespin. You can make this into a magnet by putting a sticky magnet on the back of the clothespin.
Introduce craft: Who died for our sins and rose again on the third day?
christiancrafters.com- The Colors of Christ Cross
crafts.kaboose.com- change the colors of the beads to make this cross
*Tip: Hot glue the blue, white, and red beads together.
Introduce game: What was rolled away from the tomb where Jesus laid?
Who’s Got The Stone?
Need: One small rock
Directions: One student is picked to be “It”. All the students (except "It") put both of their hands together and form a cup with just a little hole up on top. The teacher walks around and pretends to put the stone in someone's hand. One student will actually get the stone. The student who is “It” is then asked by the teacher, "Who's got the stone?". Whoever has the stone is "It". (Game is like “Button, Button, Who’s Got the Button?).
You Can’t Keep Jesus Down- Your children will discover that even thought people tried to keep Jesus in the grave, they couldn’t; just as Jesus said. (The Encyclopedia of Bible Games for Children’s Ministry, page 148).
kidssundayschool.com- In the Tomb, Out of the Tomb
A good energy burner, game can be adjusted to fit many different themes.
christianpreschoolprintables.com- Easter Bingo
This is a fun game you can play with your classroom around Easter time. The pictures depicted tell the true Easter story of the resurrection of Jesus Christ. (Scroll down to this.)
Impossible Knot! (Jesus Rises From the Dead)- This game will seem impossible to kids at first, just as Jesus’ resurrection must have seemed impossible at the time. (The Encyclopedia of Bible Games for Children’s Ministry by Group Publishing, page 100 & 101.)
Sight Seeing (Jesus Appears to Mary)- As kids explore Jesus’ appearance to Mary, they will learn that god always keeps his word, no matter how hard it is to believe. (The Encyclopedia of Bible Games for Children’s Ministry by Group Publishing, page 102 & 103.)
Easter- lots of games listed in this lesson (scroll down to Games)
The Empty Tomb File Folder Game- The objective of the game is to get to the empty tomb first. Players take turns spinning the spinner and then moving their marker ahead to the next space of that color. (Like Candy Land)
Jelly Bean Prayer File Folder Game- The objective of the game is to collect the most Jelly Bean jar cards by answering questions about Jesus and get to FINISH.
first-school.ws- He Is Risen
Children color then make an easy puzzle that they can put together.
sermons4kids.com- The Empty Tomb (maze)
The Empty Tomb- lots of puzzles posted in this lesson (scroll down to Puzzles)
Easter Match Up (worksheet)- Match the words in the first column to the best available answer in the second column. For younger students you can write the words from the first column on the board and read these words to the students. Read each sentence under the second column to the students and put them into a question. Example: Who did not know if the body had been stolen or if Jesus had really come alive again? The student then answers the question and the teacher then writes the correct number for the answer beside the word.
Pflaum Publishers- Click on PGW Online Activities. Sign up for FREE. Inside you'll find features on Saints of the Season, Feasts of the Season, Catholic Culture, and Family Prayer - plus reproducible activities for preschool through junior high.
sadlierreligion.com- Kindergarten activity sheet (mobile)
sadlierreligion.com- 1st grade activity sheet
During Easter we celebrate that Jesus rose to new life. Trace the words on the Easter banner. Decorate the banner with signs of new life.
sadlierreligion.com- 2nd grade activity sheet
During the Easter season the Church sings the song of “Alleluia.” The word Alleluia means “Praise God!” Write a song to celebrate the Easter season. Include an Alleluia in your song.
sadlierreligion.com- 3rd grade activity sheet
Make an Easter Cross
sadlierreligion.com- 4th grade activity sheet
With a partner, write dialogue for a skit that tells a story of “meeting” the risen Jesus in someone around you. Use the lines below to get started. Be creative! Include props in your skit, too.
sadlierreligion.com- 5th grade activity sheet
How does your parish celebrate the Easter season? Record your observations below.
sadlierreligion.com- 6th grade activity sheet
Complete the following Easter season questionnaire. | <urn:uuid:3d7f3bb4-0b07-4c62-b11c-eecb2fe3e585> | CC-MAIN-2013-20 | http://catholicblogger1.blogspot.com/2011/03/easter.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.899818 | 2,033 | 3.640625 | 4 |
The middle school youth will come to a better understanding of the use and meaning of sacramentals, how they remind us of the Sacraments and keep us focused on God.
According to the Catechism of the Catholic Church, “Sacramentals are sacred signs instituted by the Church. They prepare men to receive the fruit of the Sacraments and sanctify different circumstances of life” (1677). Sacramentals are closely tied to our liturgical ceremonies that come to us from the Catholic Church. They are meant to remind us of the seven Sacraments. Within each Sacrament, we receive grace to live our lives for God. As an extension, sacramentals remind us of the sacred signs and symbols in each of the Sacraments. Sacramentals remind us of our Catholic faith in everyday life. They are often small images or items that remind us of Jesus, the Church or the Sacraments. When displayed, they tell others we are Catholic.
There are many examples of sacramentals. Although there are some universal sacramentals like a crucifix or rosary, the Catechism says that the Church allows for people to have sacramentals that may be specific to a culture as long as it expresses a truth of the Catholic faith (1679). Other examples of sacramentals include holy water, relics, statues of saints, prayer cards, or devotionals to a particular saint. | <urn:uuid:88bb0f62-2bef-42fd-b3b5-1cdfc93c3e7b> | CC-MAIN-2013-20 | http://catholicyouthministry.com/sacramentals/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.943014 | 283 | 3.8125 | 4 |
Today, on November 19, is World Toilet Day, declared by the World Toilet Organization – who would have thought something like that exists?
But there’s a meaning to it, befauce over 2.6 billion people don’t have toilets at all – and for many more, the situation isn’t much better. Which isn’t all too good for people’s health, much too often there’s bad hygiene, and the excrements are discharged directly into the environment.
The United Nations claim that more than 5 million children die every year from sanitation related diseases such as diarrhoea. More than a billion people without sanitary facilities relieve themselves on streets and in rivers, heavily polluting the water. The most important source of water contamination in developing countries is due to the lack of adequate sanitation facilities. Although public toilets are available in most countries, most of them are poorly maintained.
The WTO envisages clean, safe, affordable, ecologically sound and sustainable sanitation. It aims to advocate sustainable toilet systems through capacity building and public education, and by implementing real time projects.
- “Ihre Gesundheit liegt uns sehr am Herzen” 2010-04-14 (2)
- Freedom? 2007-07-31
- Spiritual healing and publishing your phone number 2008-10-23 (6)
- “Das Geheimnis der Zauberhände” 2008-07-29 (10)
- 20 Years Ago or
How to turn 5 digits into a song 2010-02-11 (1) | <urn:uuid:5dc4b826-767f-4a47-8197-ced5d1663d44> | CC-MAIN-2013-20 | http://cimddwc.net/2007/11/19/welt-toiletten-tag/?langswitch_lang=en | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.89466 | 336 | 3.578125 | 4 |
Crocodilians are members of the taxon Crocodilia and include the crocodiles, alligators, gavials, and caimans. With some possible exceptions, crocodilians are more closely related to birds than to any other living reptile.
Crocodilians are large reptiles with powerful limbs and tails and heavy plates of bone (osteoderms) beneath the skin. All crocodilian species have webbed feet, a transparent membrane drawn across the eye underwater, nostrils at the top of the snout, and other adaptations for an aquatic lifestyle. Crocodilians also have well-developed senses of smell, sight, and hearing. Of the 23 crocodilian species that exist in the world, the American crocodile and the American alligator are native to the United States. A third species, the common caiman, is an introduced species in Florida.
- Britton, Adam. "World Countries Containing Crocodilians." Species Distribution Maps. Crocodilian Species List. http://www.flmnh.ufl.edu/cnhc/csl-maps.htm (Accessed: 2007)
- Pough, Harvey F., Robin M. Andrews, John E. Cadle, Martha L. Crump, Alan H. Savitzky, and Kentwood D. Wells. Herpetology. 3rd Ed. Upper Saddle River, New Jersey: Pearson Education, Inc., 2004.
- Uetz, Peter. "Family Crocodylidae (Crocodiles and Relatives)." The Reptile Database. http://www.tigr.org/reptiles/families/Crocodylidae.html. Accessed June 24, 2008.
- Uetz, Peter. "How Many Species?" The Reptile Database. http://www.reptile-database.org. Accessed June 24, 2008.
No one has provided updates yet. | <urn:uuid:a7ffb095-c591-4f48-a9d4-8cc5d98d1d24> | CC-MAIN-2013-20 | http://eol.org/data_objects/14922355 | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.822608 | 400 | 3.859375 | 4 |
A gender stereotype is a set of beliefs about the characteristics of men and women.
According to the cognitive approach to gender stereotypes, people tend to exaggerate
the differences between the sexes when they are actually relatively small. Nonetheless,
these stereotypes guide the way we process information and influence our cognitive processes.A gender stereotype contributes to us having different schemas
for male and female behavior,it can lead us to interpreting things as male or female,
and tends to make us see the male experience as normative while we look for reasons that
the female deviates from that norm. We also remember gender-consistent information better
than gender-inconsistent information as with the experiment measuring ERP responses to
"The doctor prepared himself for the operation" versus "the doctor prepared herself for
the operation".A much larger effect was noticed when the pronoun disagreed with the
expectation formed by a gender stereotype.
One phenomenon associated with gender stereotypes and our cognitive processes is Claude Steel's hypothesis of stereotype threat. This hypothesis proposes that negative group stereotypes cause anxiety and can hurt test performance. In a research study conducted atNew York University, women with high ability in math outperformed their male counterparts on a math test when the test was described as free from gender differences. Another group took the same test under normal testing conditions with no additional description of the test and only performed just as well as the men. In a seperate study under this same condition, the women performed significantly worse than the men. While some claim the effect of this stereotype anxiety is relatively small, it is worth considering when we talk about congnitive differences between men and women. Another issue to be mindful of with this topic is when and how these stereotypes are acquired. Several studies have been done with toddlers asking them to asess toys as being for boys, for girls, or for boys and girls and have shown that environmentalfactors (like parents) can give a child percieved social constraints that lead to gender stereotyping
This site created by Emma Stitt
Picture credit goes to jewishphilosopher.blogspot.com,wandco.com, and wordpress.com | <urn:uuid:6abca91d-97cb-42bb-987c-a7b9dfa6138b> | CC-MAIN-2013-20 | http://faculty.mercer.edu/spears_a/studentpages/gender_stereotypes/webpage.html | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.948005 | 438 | 3.828125 | 4 |
- The Skeleton
- The Axial Skeleton
- The Appendicular Skeleton
- Bones of the Upper Appendage (Arm)
- Bones of the Lower Appendage (Leg)
- The Joints
- Types of Functional Joints
- Types of Structural Joints
- Types of Synovial Joints
- Joint Range of Motion
- Joints of the Upper Appendage (Arm)
- Joints of the Lower Appendage (Leg)
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Our musculoskeletal system is made up of muscles, tendons, ligaments, bones, cartilage, joints and bursae. Our muscles work with the nervous system to contract when stimulated with impulses (messages through the receptor arc) from motor nerves. The muscles are attached to the bones with ligaments. Our skeletal system is made mostly of bones and cartilage. Bones attach to bones with cartilage or ligaments. Bursae are small fluid filled at friction points near joints to protect ligaments and tendons from rubbing against bare bones.
Our skeleton forms a strong, solid internal framework of bones for our body, yet our bones only make up about 14% of our total body weight. Bones get their elasticity from tough elastic ropelike fibers of collagen. The core of some small bones is called marrow, it is soft and jellylike. The hard outside of bones is reinforces by strong rods called osteons.Bones have special cells called osteoblasts that make new bone and osteoclasts that break up the old bone. Bones grow by getting longer on the ends called the epiphyseal plate or growth plate. Bones are made rigid by hard deposits of minerals like phosphate and calcium. The bones of the skeleton support our skin, give our body shape, protect and support our organs and make it possible for us to move by acting as single and double levers. Bones do not move on their own; muscles move our bones by pulling on them. Muscles cannot push against the bone, so muscles come in pairs, one muscle pulls the bone one way and the paired muscle pulls the bone back the other way. We have a total of 233 bones. Some bones come in pairs that are almost identical in size and shape — the bones in the left arm are the same as the bones in the right arm. There are also single bones in the median plane of our body — the vertebrae in our back and neck. However, since our bones are constantly being rebuilt as we get older, both their structure and form can change. Our bones can be rigidly connected to each other or joined by rubbery cartilage, or flexibly linked by muscular or ligamentous joints. An adult skeleton has 206 bones, although some people have extra bones in their spine (backbone). A baby’s skeleton has 300 bones or more. As the baby grows, some of the bones fuse such as the bones in the skull and the pelvis. Most girls and women have smaller skeletons than boys and men of the same age. There are two main parts of the skeleton—the axial skeleton and the appendicular skeleton.
The Axial Skeleton
The axial skeleton (trunk) is made up of the 80 bones in our upper body. Bones of the axial skeleton include:
- Skull (facial and cranial bones)
- Vertebrae in the spine (backbones)
- Sternum (breastbone)
The Appendicular Skeleton
There are 126 bones in the arms, shoulders, hips, and legs. The appendicular skeleton is made up of our limbs or appendages—two arms and two legs—our pelvis and right and left shoulders. Our arms hang from our shoulders and legs attached to our hips.
- Shoulder girdle—scapula (shoulder blade), clavicle (collar bone)
- Humerus—long bone of the upper arm
- Radius—long bone of the forearm; connects with the humerus to form the elbow
- Ulna—long bone of the forearm; connects with the humerus to form the elbow
- Carpals—8 small bones of the wrist
- Metacarpals—small bones of the hand
- Phalanges—14 bones of the fingers (3 in each finger) and thumb (2 in the thumb)
Bones of the Lower Appendage (Leg)
- Pelvic Girdle—made up of the right and left hip bones which are joined in the back with the sacrum and in the front at the symphysis pubis
- Hipbone—made of the ilium, pubis and ischium
- Femur—long bone of the thigh and longest bone in the body; connects with pelvis to form and hip joint and the tibia and fibula to form the knee joint
- Tibia—long bone of the lower leg (shin bone); connects with the femur to form the knee
- Fibula—thinner, long bone of the lower leg
- Patella—kneecap (Learn more about knee anatomy)
- Tarsals—small bones of the hand
- Phalanges—bones of the toes (3 in each toe and 2 in the big toe)
Joints—also called articulations—are formed where the surfaces of two or more bones meet and articulate with each other. There are about 400 joints in the human body. Joints allow both movement and flexibility. Joints are classified by how much movement they allow—function—or what they are made of—structure. Joints are usually classified structurally by the tissue that connects them. The tissue could be cartilage, fibrous tissue, synovial fluid, or some combination of the three. Functionally, joints can be classified by the degree of movement possible, the number of bones involved, and the complexity of the joint. Most body joints allow us to move, and some only allow movement in certain ways. Fixed or immovable joints allow no movement. A dislocated joint happens when the bones of the joint are forced out-of-place, usually while playing sports but can also happen with accidents. There are 3 major functional joints and 3 major types of structural joints.
Types of Functional Joints
- immovable (synarthrosis) joints—the bones are held together by fibrous tissue so they don’t move at all; example is the skull bones
- slightly movable (amphiarthrosis) joints—the bones are held together by cartilage that allows only a little movement; examples are the joints in the spine
- freely movable (diarthrosis) joints—also called synovial joints, allow the most movement; examples are hip and knee joints
Types of Structural Joints
- fibrous: the articular surfaces (point on the bone’s surface where the two bones meet) are held together by fibrous connective tissue. Very little movement is possible. Examples of fibrous joints are sutures, syndesmoses, and gomphoses.
- cartilaginous (amphiarthroses): the bones in cartilaginous joints are held together by cartilage which allows slight movement.
- synchondroses-these are temporary joints where the cartilage converts to bone by the time we are adults. The growth plates of long bones are examples of this type of joint.
- symphyses-these joints have a pad of fibrocartilage separating the bones; an example is the symphysis pubis
- synovial-the bony surfaces on the ends of the bones are covered with articular cartilage and separated by a slippery, lubricating fluid called synovia. They bones are held together in the joint by ligaments lined with synovial membranes which produce the synovial fluid. These freely moving joints are mostly found in our arms and legs. Synovial joints also include:
- a joint cavity or joint space: space between the articulating surfaces; articulating surfaces are the bone surfaces that move against each other when the joint moves. The articulating surfaces are covered with a layer of hyaline cartilage that cushions and protects the bones. The synovial membrane defines the boundaries of the joint space—everything outside of the synovial membrane is outside the joint space. The synovial membrane is wrapped by layers of connective tissue that form the joint capsule.
- an articular capsule: a sac-like structure that surrounds the joint and has an outer layer lined with a synovial membrane (synovium) that makes the synovial fluid. Synovial fluid acts as a lubricant, forms a fluid seal and helps distribute the force placed on the joint.
- reinforcing ligaments: tough, fibrous connective tissues that connect the bones and reinforce the joint capsule. On the outside of the joint capsule are thick strap-like bands, called collateral ligaments. These ligaments direct the force that travels through the joint and keep the joint on track. Outside of these structures are the muscles that travel across the joint.
Based on the type of movement the joint allows and its structure, synovial joints can be put into several categories.
- gliding (plane) joint: have flat or slightly curved articular surfaces and allow gliding movements. The way they are bound together by the ligaments may not allow movement in all directions. Examples of a gliding joint are the intertarsal and intercarpal joints of the hands and feet.
- hinge joint: have a convex (curved outward) part of bone that fits into the concave (curved inward) part of another bone. The action of the hinge joint is like that of a door hinge and motion is limited to bending and straightening. Our elbows and knees are examples of hinge joints.
- pivot (swivel) joint: have a bone with a rounded end fitting into a groove in another bone. Pivot joints allow one bone to pivot on the other bone. An example is head of the radius rotates within the groove of the ulna.
- condylar (ellipsoidal) joint: these joints have a bony surface that is oval-shaped fitting into a concave surface of another bone. These joints allow bending, straightening, abduction, adduction and circumduction. An example of condular joints are in the hands.
- saddle joint: these joints are simialr to condylar joints but allow more movement. The only saddle joints are in the thumb.
- ball-and-socket joint: these bones fit together like a ball in a socket: the round end of one bone fits into the concave socket of the other bone. The only ball-and-socket joints are the shoulders and hips.
Joint Range of Motion
Range-of-motion means how far and in what direction a joint can move. All joints have a normal range of motion–that is when they are healthy and normal they should be able to move a certain distance and direction. Range of motion is measured in angles using a goniometer. A joint has a limited range of motion when it cannot move to it’s full range. Limited motion can be cause be injury, a mechanical problem or a disease process. When you have a physical exam, your range of motion is checked to see if you have full or limited range of motion. Surgery can also cause limit the range of motion in a joint. These are degrees of normal ranges of motion:
- shoulder: bend from 0-90°; straighten 90-0 °; move away from the body 0-90° ; move towards the body 90-0° ; rotate away form the center of the body 0-90° ; rotate toward the center of the body 90-0°
- elbow: bend from 0-90°; straighten 90-0 °; move away from the body 0-90° ; move towards the body 90-0° ; rotate away form the center of the body 0-90° ; rotate toward the center of the body 90-0°
- wrist: bend from 0-90°; straighten 0-70 °; move away from the body 0-25° ; move towards the body 0-65°
- metacarpophalangeal fingers: bend down 0-90°; straighten 0-30°
- interphalangeal – proximal: bend 0-120°; straighten 120-0°
- interphalangeal – distal: bend 0-80°; straighten 80-0°
- metacarpophalangeal-thumb: bend 0-70°; straighten 60-0°; abduct 0-50°; adduct 40-0°
- interphalangeal – thumb: bend 0-90°; straighten 90-0°
- hip: bend from 0-125°; straighten 115-0°; move away from the body 0-45° ; move towards the body 45-0° ; rotate away form the center of the body 0-45° ; rotate toward the center of the body 45-0° ; abduction 0-25°; adduction 20-0°
- knee: bend from 0-130°; straighten 120-0°
- ankle: bend downward 0-50°; move upward 0-20°
- foot: turn inward 0-35°; turn outward 0-25°
- metatarsophalangeal toes: bend down 0-35°; bend up 0-80°
- interphalangeal: bend down 0-50°; bend up 50-80°
Joints of the Upper Appendage (Arm)
- Shoulder—links the arm to the trunk. It is located away from the trunk so the arm can move freely. The arm hangs vertically beside the trunk.
- Elbow—the elbow can bend from 15 – 180 °. When the elbow is bent, the shoulder and metacarpus are in the same plane.
- Carpal—wrist joint
- Phalangeal—finger joints
Joints of the Lower Appendage (Leg)
- Hip—links the leg to the trunk. The leg hangs vertically below the trunk. The hip joint is where the hipbone joins the femur. The hip joint can bend from 0-125 ° and straightened from 115 to 0 °.
- Knee—the knee can bend from 0 – 130 ° and extend from 120 – 0 °. The knee is formed by the tibia, fibular, femur and patella.
- Metatarsal—joints in the foot
- Phalangeal—joints in the toes | <urn:uuid:490db4d9-f5cd-46cb-8c16-3555613de1aa> | CC-MAIN-2013-20 | http://healthpages.org/anatomy-function/musculoskeletal-system-bones-joints-cartilage-ligaments/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.901075 | 3,081 | 4.1875 | 4 |
Eating disorders occur most often in young adolescents and teens; however, young children can develop eating disorders as well. Healthcare professionals are seeing a disturbing trend of children as young as age 5 developing eating disorders. While these eating disturbances often seem similar to the anorexia nervosa and bulimia, most commonly found in young teen girls, those occurring at a very young age often have other causes.
With this disorder, children use food refusal as a means of manipulation. The behavior is often erratic and inconsistent. While this tactic is certainly frustrating for parents, it is sometimes associated with a recent source of stress or sadness and is not usually thought of as a threat to health.
With restrictive eating, very young children eat a variety of foods, but clearly restrict portions. The underlying causes of this disorder remain unclear and although children exhibiting restrictive eating habits may have low weight or growth for their age, they generally eat a balanced diet, albeit portion restricted, causing medical staff to consider them healthy in most cases. As with most eating disturbances in very young children, restrictive eating seems to have no basis in a preoccupation with body image and weight.
Selective eating disorder syndrome can begin as early as infancy and can mimic the common picky eating habits of many infants and toddlers. Children exhibiting picky eating behavior usually overcome their aversion to other foods relatively quickly before any nutritional threat is imminent. Those with selective eating disorder only eat foods from very narrow categories, often those high in simple carbohydrates.
Recognizing the symptoms of selective eating and taking steps to mitigate negative nutritional and psychological consequences can stop the child from developing a full-blown disorder that threatens health and well-being. Children with true selective eating disorder have an aversion to certain food textures and smells. They associate the texture, odor, or both with a traumatic incident, which they now associate with food. When coaxed to try the food group associated with the event, they often gag, cough, or choke. This disorder is often associated with an underlying psychological condition involving anxiety or autism.
Food Avoidance Emotional Disorder
Children can exhibit symptoms of food avoidance emotional disorder (FAED) very early in life. With this disorder, children can be as thin or thinner than those with untreated anorexia nervosa. The difference being that these children often feel shame at their thin bodies and know that their eating habits are irrational. Symptoms are closely related to obsessive-compulsive disorder. Many times, children with this disorder do not know exactly why they cannot overcome their eating issues, but desperately want to eat like their peers. They are often plagued with intense worry, sadness, and anxiety. Untreated, atypical eating disorders, such as FAED, can result in profound health and social issues for the child.
Eating disorders in very young children can often mirror those of adolescents and teens with anorexia nervosa or bulimia, but generally manifest themselves much differently in the mind of the child patient. Anorexics and bulimics usually have profound body image and self-esteem issues because of their emotional stresses. Very young children with eating disorders do not have body image concerns. They exhibit no fear of becoming overweight. These children often have a first or second degree relative with an eating disorder, which indicates a genetic factor in the disease. Many have anxiety disorders and fear of separation from their primary parent (usually their mother). Other contributing factors include perfectionism, inability to effectively cope with daily stresses, and depression marked by tearfulness.
Eating disorders in pre-pubescent children are new to prominence in the medical community. Consequently, specific treatments have not been established, but possible treatment options can be administered by a pediatric physician or psychiatrist. Concerned parents can stay informed and involved by keeping regular appointments with their child’s pediatrician. Those who strongly suspect the onset of an eating disorder in their prepubescent child should bring the child in for evaluation by a pediatric psychiatrist. The psychiatric physician may prescribe medication to attenuate the underlying anxiety or obsessive-compulsive condition thought to cause the child difficulty. Both individual and family therapy may benefit the family unit and the child specifically. | <urn:uuid:01388b0f-0053-49b6-9dc3-c0cbe616cb91> | CC-MAIN-2013-20 | http://medtopicwriter.com/2011/01/29/eating-disorders-in-very-young-children/ | s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368696383508/warc/CC-MAIN-20130516092623-00041-ip-10-60-113-184.ec2.internal.warc.gz | en | 0.970832 | 838 | 3.765625 | 4 |
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