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human accelerated regions ( hars ), first described in august 2006, are a set of 49 segments of the human genome that are conserved throughout vertebrate evolution but are strikingly different in humans. they are named according to their degree of difference between humans and chimpanzees ( har1 showing the largest degree of human - chimpanzee differences ). found by scanning through genomic databases of multiple species, some of these highly mutated areas may contribute to human - specific traits. others may represent loss of functional mutations, possibly due to the action of biased gene conversion rather than adaptive evolution. several of the hars encompass genes known to produce proteins important in neurodevelopment. har1 is a 106 - base pair stretch found on the long arm of chromosome 20 overlapping with part of the rna genes har1f and har1r. har1f is active in the developing human brain. the har1 sequence is found ( and conserved ) in chickens and chimpanzees but is not present in fish or frogs that have been studied. there are 18 base pair mutations different between humans and chimpanzees, far more than expected by its history of conservation. har2 includes hacns1 a gene enhancer " that may have contributed to the evolution of the uniquely opposable human thumb, and possibly also modifications in the ankle or foot that allow humans to walk on two legs ". evidence to date shows that of the 110, 000 gene enhancer sequences identified in the human genome, hacns1 has undergone the most change during the evolution of humans following the split with the ancestors of chimpanzees. the substitutions in har2 may have resulted in loss of binding sites for a repressor, possibly due to biased gene conversion. = = har genes = = har01 : har1f & har1r har02 : centg2 including the hacns1 module har03 : mad1l1 har04 :? har05 : wnk1 har06 : wwox har07 :? har08 : pou6f2 har09 : ptprt har10 : fhit har11 : dmd har12 :? har20 : ppargc1a har21 : npas3 - association with psychiatric disorders har23 : mgc27016 har24 :
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##r10 : fhit har11 : dmd har12 :? har20 : ppargc1a har21 : npas3 - association with psychiatric disorders har23 : mgc27016 har24 : skap2 har28 : adgrl4 ( latrophilin ) har31 : auts2 har33 : tbc1d22a har38 : itpr1 har40 : zbtb16 har43 : agbl4 har44 : fhit har45 : pola har47 : klhl14 ( kelch - like protein ) = = = human accelerated regions = = = the har regions may be downloaded from : ncbi : https : / / www. ncbi. nlm. nih. gov / geo / query / acc. cgi? acc = gse180714 ucsc genome browser : https : / / genome. ucsc. edu / cgi - bin / hgtracks? db = hg38 & lastvirtmodetype = default & lastvirtmodeextrastate = & virtmodetype = default & virtmode = 0 & nonvirtposition = & position = chry % 3a12356610 % 2d12382346 & hgsid = 2451636823 _ q4hu6krd6b9l1onskk5jmrwgm1ol = = see also = = ultra - conserved element = = references = =
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the moving magnet and conductor problem is a famous thought experiment, originating in the 19th century, concerning the intersection of classical electromagnetism and special relativity. in it, the current in a conductor moving with constant velocity, v, with respect to a magnet is calculated in the frame of reference of the magnet and in the frame of reference of the conductor. the observable quantity in the experiment, the current, is the same in either case, in accordance with the basic principle of relativity, which states : " only relative motion is observable ; there is no absolute standard of rest ". however, according to maxwell's equations, the charges in the conductor experience a magnetic force in the frame of the magnet and an electric force in the frame of the conductor. the same phenomenon would seem to have two different descriptions depending on the frame of reference of the observer. this problem, along with the fizeau experiment, the aberration of light, and more indirectly the negative aether drift tests such as the michelson – morley experiment, formed the basis of einstein's development of the theory of relativity. = = introduction = = einstein's 1905 paper that introduced the world to relativity opens with a description of the magnet / conductor problem : it is known that maxwell's electrodynamics – as usually understood at the present time – when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena. take, for example, the reciprocal electrodynamic action of a magnet and a conductor. the observable phenomenon here depends only on the relative motion of the conductor and the magnet, whereas the customary view draws a sharp distinction between the two cases in which either the one or the other of these bodies is in motion. for if the magnet is in motion and the conductor at rest, there arises in the neighborhood of the magnet an electric field with a certain definite energy, producing a current at the places where parts of the conductor are situated. but if the magnet is stationary and the conductor in motion, no electric field arises in the neighborhood of the magnet. in the conductor, however, we find an electromotive force, to which in itself there is no corresponding energy, but which gives rise – assuming equality of relative motion in the two cases discussed – to electric currents of the same path and intensity as those produced by the electric forces in the former case. an overriding requirement on the descriptions in different frameworks is that they be consistent. consistency is an issue because newton
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in the two cases discussed – to electric currents of the same path and intensity as those produced by the electric forces in the former case. an overriding requirement on the descriptions in different frameworks is that they be consistent. consistency is an issue because newtonian mechanics predicts one transformation ( so - called galilean invariance ) for the forces that drive the charges and cause the current, while electrodynamics as expressed by maxwell's equations predicts that the fields that give rise to these forces transform differently ( according to lorentz invariance ). observations of the aberration of light, culminating in the michelson – morley experiment, established the validity of lorentz invariance, and the development of special relativity resolved the resulting disagreement with newtonian mechanics. special relativity revised the transformation of forces in moving reference frames to be consistent with lorentz invariance. the details of these transformations are discussed below. in addition to consistency, it would be nice to consolidate the descriptions so they appear to be frame - independent. a clue to a framework - independent description is the observation that magnetic fields in one reference frame become electric fields in another frame. likewise, the solenoidal portion of electric fields ( the portion that is not originated by electric charges ) becomes a magnetic field in another frame : that is, the solenoidal electric fields and magnetic fields are aspects of the same thing. that means the paradox of different descriptions may be only semantic. a description that uses scalar and vector potentials φ and a instead of b and e avoids the semantical trap. a lorentz - invariant four vector aα = ( φ / c, a ) replaces e and b and provides a frame - independent description ( albeit less visceral than the e – b – description ). an alternative unification of descriptions is to think of the physical entity as the electromagnetic field tensor, as described later on. this tensor contains both e and b fields as components, and has the same form in all frames of reference. = = background = = electromagnetic fields are not directly observable. the existence of classical electromagnetic fields can be inferred from the motion of charged particles, whose trajectories are observable. electromagnetic fields do explain the observed motions of classical charged particles. a strong requirement in physics is that all observers of the motion of a particle agree on the trajectory of the particle. for instance, if one observer notes that a particle collides with the center of a bullseye, then all observers must reach the same conclusion
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requirement in physics is that all observers of the motion of a particle agree on the trajectory of the particle. for instance, if one observer notes that a particle collides with the center of a bullseye, then all observers must reach the same conclusion. this requirement places constraints on the nature of electromagnetic fields and on their transformation from one reference frame to another. it also places constraints on the manner in which fields affect the acceleration and, hence, the trajectories of charged particles. perhaps the simplest example, and one that einstein referenced in his 1905 paper introducing special relativity, is the problem of a conductor moving in the field of a magnet. in the frame of the magnet, a conductor experiences a magnetic force. in the frame of a conductor moving relative to the magnet, the conductor experiences a force due to an electric field. the magnetic field in the magnet frame and the electric field in the conductor frame must generate consistent results in the conductor. at the time of einstein in 1905, the field equations as represented by maxwell's equations were properly consistent. newton's law of motion, however, had to be modified to provide consistent particle trajectories. = = transformation of fields, assuming galilean transformations = = assuming that the magnet frame and the conductor frame are related by a galilean transformation, it is straightforward to compute the fields and forces in both frames. this will demonstrate that the induced current is indeed the same in both frames. as a byproduct, this argument will also yield a general formula for the electric and magnetic fields in one frame in terms of the fields in another frame. in reality, the frames are not related by a galilean transformation, but by a lorentz transformation. nevertheless, it will be a galilean transformation to a very good approximation, at velocities much less than the speed of light. unprimed quantities correspond to the rest frame of the magnet, while primed quantities correspond to the rest frame of the conductor. let v be the velocity of the conductor, as seen from the magnet frame. = = = magnet frame = = = in the rest frame of the magnet, the magnetic field is some fixed field b ( r ), determined by the structure and shape of the magnet. the electric field is zero. in general, the force exerted upon a particle of charge q in the conductor by the electric field and magnetic field is given by ( si units ) : f = q ( e + v × b ), { \ displaystyle \ math
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zero. in general, the force exerted upon a particle of charge q in the conductor by the electric field and magnetic field is given by ( si units ) : f = q ( e + v × b ), { \ displaystyle \ mathbf { f } = q \ left ( \ mathbf { e } + \ mathbf { v } \ times \ mathbf { b } \ right ), } where q { \ displaystyle q } is the charge on the particle, v { \ displaystyle \ mathbf { v } } is the particle velocity and f is the lorentz force. here, however, the electric field is zero, so the force on the particle is f = q v × b. { \ displaystyle \ mathbf { f } = q \ mathbf { v } \ times \ mathbf { b }. } = = = conductor frame = = = in the conductor frame, there is a time - varying magnetic field b ′ related to the magnetic field b in the magnet frame according to : b ′ ( r ′, t ′ ) = b ( r t ′ ) { \ displaystyle \ mathbf { b }'( \ mathbf { r'}, t') = \ mathbf { b } ( \ mathbf { r _ { t'} } ) } where r t ′ = r ′ + v t ′ { \ displaystyle \ mathbf { r _ { t'} } = \ mathbf { r'} + \ mathbf { v } t'} in this frame, there is an electric field, and its curl is given by the maxwell - faraday equation : ∇ × e ′ = − ∂ b ′ ∂ t ′. { \ displaystyle { \ boldsymbol { \ nabla } } \ times \ mathbf { e }'= - { \ frac { \ partial \ mathbf { b }'} { \ partial t'} }. } this yields : e ′ = v × b. { \ displaystyle \ mathbf { e }'= \ mathbf { v } \ times \ mathbf { b }. } a charge q in the conductor will be at rest in the conductor frame. therefore, the magnetic force term of the lorentz force has no effect, and the force on the charge is given by f ′ = q e ′ = q v × b. { \ displaystyle \ mathbf { f }'= q \ mathbf { e } '
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of the lorentz force has no effect, and the force on the charge is given by f ′ = q e ′ = q v × b. { \ displaystyle \ mathbf { f }'= q \ mathbf { e }'= q \ mathbf { v } \ times \ mathbf { b }. } this demonstrates that the force is the same in both frames ( as would be expected ), and therefore any observable consequences of this force, such as the induced current, would also be the same in both frames. this is despite the fact that the force is seen to be an electric force in the conductor frame, but a magnetic force in the magnet's frame. = = = galilean transformation formula for fields = = = a similar sort of argument can be made if the magnet's frame also contains electric fields. ( the ampere - maxwell equation also comes into play, explaining how, in the conductor's frame, this moving electric field will contribute to the magnetic field. ) the result is that, in general, e ′ = e + v × b b ′ = b − 1 c 2 v × e, { \ displaystyle { \ begin { aligned } \ mathbf { e }'& = \ mathbf { e } + \ mathbf { v } \ times \ mathbf { b } \ \ [ 1ex ] \ mathbf { b }'& = \ mathbf { b } - { \ frac { 1 } { c ^ { 2 } } } \ mathbf { v } \ times \ mathbf { e }, \ end { aligned } } } with c the speed of light in free space. by plugging these transformation rules into the full maxwell's equations, it can be seen that if maxwell's equations are true in one frame, then they are almost true in the other, but contain incorrect terms proportional to the quantity v / c raised to the second or higher power. accordingly, these are not the exact transformation rules, but are a close approximation at low velocities. at large velocities approaching the speed of light, the galilean transformation must be replaced by the lorentz transformation, and the field transformation equations also must be changed, according to the expressions given below. = = transformation of fields as predicted by maxwell's equations = = in a frame moving at velocity v, the e - field in the moving frame when there is no e - field in the stationary magnet frame maxwell
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according to the expressions given below. = = transformation of fields as predicted by maxwell's equations = = in a frame moving at velocity v, the e - field in the moving frame when there is no e - field in the stationary magnet frame maxwell's equations transform as : e ′ = γ v × b { \ displaystyle \ mathbf { e }'= \ gamma \ mathbf { v } \ times \ mathbf { b } } where γ = 1 1 − ( v / c ) 2 { \ displaystyle \ gamma = { \ frac { 1 } { \ sqrt { 1 - { ( v / c ) } ^ { 2 } } } } } is called the lorentz factor and c is the speed of light in free space. this result is a consequence of requiring that observers in all inertial frames arrive at the same form for maxwell's equations. in particular, all observers must see the same speed of light c. that requirement leads to the lorentz transformation for space and time. assuming a lorentz transformation, invariance of maxwell's equations then leads to the above transformation of the fields for this example. consequently, the force on the charge is f ′ = q e ′ = q γ v × b. { \ displaystyle \ mathbf { f }'= q \ mathbf { e }'= q \ gamma \ mathbf { v } \ times \ mathbf { b }. } this expression differs from the expression obtained from the nonrelativistic newton's law of motion by a factor of γ { \ displaystyle \ gamma }. special relativity modifies space and time in a manner such that the forces and fields transform consistently. = = modification of dynamics for consistency with maxwell's equations = = the lorentz force has the same form in both frames, though the fields differ, namely : f = q [ e + v × b ]. { \ displaystyle \ mathbf { f } = q \ left [ \ mathbf { e } + \ mathbf { v } \ times \ mathbf { b } \ right ]. } see figure 1. to simplify, let the magnetic field point in the z - direction and vary with location x, and let the conductor translate in the positive x - direction with velocity v. consequently, in the magnet frame where the conductor is moving, the lorentz force points in the negative y - direction, perpendicular to both the velocity, and the b - field. the force
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conductor translate in the positive x - direction with velocity v. consequently, in the magnet frame where the conductor is moving, the lorentz force points in the negative y - direction, perpendicular to both the velocity, and the b - field. the force on a charge, here due only to the b - field, is f y = − q v b, { \ displaystyle f _ { y } = - qvb, } while in the conductor frame where the magnet is moving, the force is also in the negative y - direction, and now due only to the e - field with a value : f y ′ = q e ′ = − q γ v b. { \ displaystyle { f _ { y } }'= qe'= - q \ gamma vb. } the two forces differ by the lorentz factor γ. this difference is expected in a relativistic theory, however, due to the change in space - time between frames, as discussed next. relativity takes the lorentz transformation of space - time suggested by invariance of maxwell's equations and imposes it upon dynamics as well ( a revision of newton's laws of motion ). in this example, the lorentz transformation affects the x - direction only ( the relative motion of the two frames is along the x - direction ). the relations connecting time and space are ( primes denote the moving conductor frame ) : x ′ = γ ( x − v t ), x = γ ( x ′ + v t ′ ), t ′ = γ ( t − v x c 2 ), t = γ ( t ′ + v x ′ c 2 ). { \ displaystyle { \ begin { aligned } x'& = \ gamma \ left ( x - vt \ right ), & x & = \ gamma \ left ( x'+ vt'\ right ), \ \ [ 1ex ] t'& = \ gamma \ left ( t - { \ tfrac { vx } { c ^ { 2 } } } \ right ), & t & = \ gamma \ left ( t'+ { \ tfrac { vx'} { c ^ { 2 } } } \ right ). \ end { aligned } } } these transformations lead to a change in the y - component of a force : f y ′ = γ f y. { \ displaystyle { f _ { y } }'= \ gamma f _ { y }. } that is, within lorentz
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transformations lead to a change in the y - component of a force : f y ′ = γ f y. { \ displaystyle { f _ { y } }'= \ gamma f _ { y }. } that is, within lorentz invariance, force is not the same in all frames of reference, unlike galilean invariance. but, from the earlier analysis based upon the lorentz force law : γ f y = − q γ v b, f y ′ = − q γ v b, { \ displaystyle \ gamma f _ { y } = - q \ gamma vb, \ quad { f _ { y } }'= - q \ gamma vb, } which agrees completely. so the force on the charge is not the same in both frames, but it transforms as expected according to relativity. = = see also = = = = references and notes = = = = further reading = = einstein, a. ( 1916 ). relativity : the special and general theory. new york : crown. isbn 0 - 517 - 02961 - 8. { { cite book } } : isbn / date incompatibility ( help ) feynman, richard p. ; leighton, robert b. ; sands, matthew ( 2006 ). the feynman lectures on physics. vol. 2. pearson / addison - wesley. pp. 13 – 6 chapter 13. isbn 0 - 8053 - 9045 - 6. ( the relativity of magnetic and electric fields ) misner, charles ; thorne, kip s. & wheeler, john archibald ( 1973 ). gravitation. san francisco : w. h. freeman. isbn 0 - 7167 - 0344 - 0. landau, l. d. & lifshitz, e. m. ( 1975 ). classical theory of fields ( fourth revised english ed. ). oxford : pergamon. isbn 0 - 08 - 018176 - 7. jackson, john d. ( 1998 ). classical electrodynamics ( 3rd ed. ). wiley. isbn 0 - 471 - 30932 - x. c møller ( 1976 ). the theory of relativity ( second ed. ). oxford uk : oxford university press. isbn 0 - 19 - 560539 - x. oclc 220221617. = = external links = = magnets and conductors in special relativity
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signal chain, or signal - processing chain is a term used in signal processing and mixed - signal system design to describe a series of signal - conditioning electronic components that receive input ( data acquired from sampling either real - time phenomena or from stored data ) sequentially, with the output of one portion of the chain supplying input to the next. signal chains are often used in signal processing applications to gather and process data or to apply system controls based on analysis of real - time phenomena. = = definition = = this definition comes from common usage in the electronics industry and can be derived from definitions of its parts : signal : " the event, phenomenon, or electrical quantity, that conveys information from one point to another ". chain : " 1. any series of items linked together. 2. pertaining to a routine consisting of segments which are run through the computer in tandem, only one segment being within the computer at any one time and each segment using the output from the previous program as its input ". the concept of a signal chain is familiar to electrical engineers, but the term has many synonyms such as circuit topology. the goal of any signal chain is to process a variety of signals to monitor or control an analog -, digital -, or analog - digital system. = = see also = = audio signal flow daisy chain ( electrical engineering ) feedback = = references = = = = external links = = signal chain basics from www. planetanalog. com
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megakaryocyte – erythroid progenitor cells ( meps ), among other blood cells, are generated as a result of hematopoiesis, which occurs in the bone marrow. hematopoietic stem cells ( hsc ) can differentiate into one of two progenitor cells : the common lymphoid progenitor and the common myeloid progenitor. meps derive from the common myeloid progenitor lineage. megakaryocyte – erythroid progenitor cells must commit to becoming either platelet - producing megakaryocytes via megakaryopoiesis or erythrocyte - producing erythroblasts via erythropoiesis. most of the blood cells produced in the bone marrow during hematopoiesis come from megakaryocyte – erythroid progenitor cells. = = references = =
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sentence - final particles, including modal particles and interactional particles, are minimal lexemes ( words ) that occur at the end of a sentence and that do not carry referential meaning, but may relate to linguistic modality, register or other pragmatic effects. sentence - final particles are common in chinese, including particles such as mandarin le, ne, ba, ou, a, la, ya, and ma /, and cantonese lo and ge. these particles act as qualifiers of the clause or sentence they end. sentence - final particles are also present in japanese and many east asian languages, such as thai, and especially in languages that have undergone heavy sino - tibetan influence, such as the monguor languages. = = examples = = = = = chinese = = = yuen ren chao has described sentence - final particles as " phrase suffixes " : just as a word suffix is in construction with the word preceding it, a sentence - final particle or phrase suffix is " in construction with a preceding phrase or sentence, though phonetically closely attached to the syllable immediately preceding it ". according to chao, the sentence - final particle is phonetically close to the last word before it, but syntactically it is equidistant from every word in the whole predicate. while sentence - final particles usually do not carry meaning themselves or denote anything explicit, they may be derived from words that do carry meaning when they occur in other contexts and serve different functions. all of the sentence - final particles of standard chinese are unstressed and, unlike most syllables in the language, do not carry tone. le ( ) : expressing a completed action ( could be in the past, present, or future, depending on time markers ), or a change in state. ba ( ) : soliciting approval, softening an imperative or giving an expression, could also express mocking, sarcasm, or passive aggressiveness depending on tone and context. ou ( ) : adds friendliness or intimacy, used frequently after warnings. ma ( ) : expresses that the speaker believes something is obvious or simple, sometimes signifying frustration or impatience. can also be used to intensify a command or suggestion. a ( ) or ya ( ) : expresses excitement or emphasis. can be used in a question. the combination le a may be contracted as la ( ). ne ( ) : question particle that elicits elaboration on a topic
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) or ya ( ) : expresses excitement or emphasis. can be used in a question. the combination le a may be contracted as la ( ). ne ( ) : question particle that elicits elaboration on a topic previously discussed. can also be used to soften a question. ma ( / ) : forms a tag question. a major use of sentence - final particles in mandarin chinese specifically is thought to be as a signal of the speaker's attitude, the intended force of the statement to which the particle is attached, and " how the utterance is to be taken by the hearer. " for example, the addition of a particle may soften the tone of a question that might sound presumptuous or inappropriate without the particle. as such, sentence - final particles in this sense often perform an interpersonal function, rather than a grammatical one. nevertheless, there are cases in which sentence - final particles do perform grammatical functions, such as mandarin ma /, the " question particle, " which changes the grammatical mood of a sentence to interrogative. likewise, even though sentence - final particles can usually be omitted from a sentence without making the sentence ungrammatical or changing its meaning, some particles do contain information critical to the interpretation of an utterance's meaning, such as mandarin le. = = = japanese = = = in japanese, there are many sentence - final particles that are used in formal as well as colloquial speech. some examples include : か ka : question. it turns a declarative sentence into a question. っけ kke : doubt. used when one is unsure of something. for example, 日 たったっけ ？ ( kino datta kke ), " was it yesterday? ". often used when talking to oneself. な na : emotion. used when one wants to express a personal feeling. may be used to state a fact in which one has emotional investment, to express one's admiration or emotional excitement, to soften an imperative, or to encourage agreement, as a mild imperative. なあ na : a lengthened version of the above, expresses strong emotion, either to encourage agreement, as above, or to express one's desires, e. g. 司 を 食 ( sushi wo tabetai naa ), " i want to eat sushi ( so badly right now! ) ". ね ne : agreement. used when the speaker wants to verify or
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, e. g. 司 を 食 ( sushi wo tabetai naa ), " i want to eat sushi ( so badly right now! ) ". ね ne : agreement. used when the speaker wants to verify or otherwise show agreement, reach consensus, or build solidarity with the listener. の no : emphatic / informal interrogative / indirect imperative. may be used to form informal questions, or to give some sort of emphasis to one's statement. depending on intonation and context, it may soften a statement ( particularly in women's language ), or to strongly assert one's belief in something. in this sense, it may also act as an indirect imperative, by indicating what the speaker believes should happen, thus, what the listener is expected to do. さ sa : casualness, assertiveness. contrasts with ne in that, where ne helps build solidarity and agreement, sa is often used to assert the speaker's own ideas or opinions. it is often used repeatedly in conversation to retain a listener's attention. wa : soft declarative or emphatic. used primarily by women, this particle has a meaning similar to yo, but it is less assertive. よ yo : assertive. it means that you are asserting what preceded the particle as information you are confident in, particularly when supplying information the listener is believed not to know. せ ze : informal hortative / emphatic. used to push someone to do something, or to remind them of something. in certain contexts, it can carry a threatening overtone. そ zo : assertive, emphatic. used to strongly assert the speaker's decisions and opinions, and serves to discourage dissent or protest. = = = english = = = english also has some words and phrases that act somewhat like sentence final particles, but primarily only in colloquial speech. however, there are others, called tag questions, which are less colloquial and can be used for any situation. all are generally discourse particles rather than modal particles. for example : " man " in " don't do it, man. " " right " in " the blue one, right? " " no " in " you want to go, no? " " don't you " in " you want to, don't you? " " are they " in " they're not hurt, are they? " " aren't they " in " they're
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go, no? " " don't you " in " you want to, don't you? " " are they " in " they're not hurt, are they? " " aren't they " in " they're here, aren't they? " " is it " in " the plate isn't broken, is it? " " isn't it " in " the plane is here, isn't it? " all but the first are tag questions. notice how when the main sentence is affirmative, the tag question is negative, and vice versa. = = = portuguese = = = portuguese uses several sentence - final particles. for example : " ne " : mainly used to seek confirmation or agreement. it may also be used to denote sarcasm or to express that a statement is obvious. " sim " : mainly used to emphasize a statement. it's often translated as " do " as in : " eu sei, sim. " = " i do know. " " la " : used with some verbs to emphasize a negation as in " sei la. " = " i don't know. " " ja " : has many different uses, one of them is to express surprise. " o " : rarely used in writing, but common in speech. used to draw the listener's attention to something. " ai " : has many different uses, one of them is to soften a request or to make a sentence sound more colloquial. = = = spanish = = = in the same way that certain words and phrases are used as sentence final particles above in the section on english ( as discourse particles ), some spanish words and phrases can be used this way as well ; once again, these are usually called tag questions. for example : " verdad " ( right ) in " te gustan los libros, ¿ verdad? " ( you ( informal ) like books, right? ) " no " ( no ) in " le toca pasar la aspiradora, ¿ no? " ( it's your ( formal ) turn to vacuum, no? ) " no es verdad " ( isn't that right ) in " eres de peru, ¿ no es verdad? " ( you're ( informal ) from peru, isn't that right? ) note that in spanish, the question marks are placed around the tag question, and not around the entire sentence ( although english only
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¿ no es verdad? " ( you're ( informal ) from peru, isn't that right? ) note that in spanish, the question marks are placed around the tag question, and not around the entire sentence ( although english only uses the single final question mark, it is implied that the entire sentence, and not just the tag, is the question ). = = references = = = = external links = = thai particles ( large list of thai particles and exclamations with explanations and example sentences ). the typological value of the chinese modality particles (. doc )
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in public services, automatic enrolment defines programmes where citizens are automatically included unless they opt out. = = examples = = there are various examples of automatic enrolment schemes in public services across the world. examples of the use of automatic enrolment schemes in the public sector include in the enrolment of citizens into pension schemes and organ donation programmes. = = = pensions = = = italy have an automatic enrolment programme as of 2007. new zealand as of 2007. the united kingdom as of 2012. turkey as of 2017. lithuania as of 2019. poland as of 2019. ireland are planning on adopting the system, expected to commence in 2024. some countries have pursued schemes similar to automatic enrolment as seen in the above nations but have adopted slightly different approaches. singapore is a nation that compels its citizens to save 30 % of their income into a savings account, without the option of opting out. the savings go into the country's central provident fund. = = = = united kingdom = = = = automatic enrolment was introduced in the united kingdom in 2012. the scheme initially covered all uk citizens in work aged between 22 and the state pension age who earned more than £8, 105 a year ( this amount rose to £10, 000 in 2015 ), as well as all those not already enrolled in a workplace pension scheme. the uk's pensions regulator hailed the success of auto - enrolment in 2019, with figures showing that 10 million more workers were now enrolled and saving into their pensions than in 2012. there has been widespread calls from within the pensions industry for the uk government to increase the contribution level at which workers are automatically enrolled. it has been questioned as to whether the current rate of 8 % is large enough to provide a healthy retirement income. industry figures often call for the contribution rate to be scaled up to above 12 % but some have even called for it to go as high as 16 %. however, there are some who question how this would affect the incomes of those on lower salaries. = = = organ donation = = = organ donation in some countries such as austria = = benefits and drawbacks = = automatic enrolment is recommended in the book nudge by thaler and sunstein, as it promotes higher participation rates than when citizens are left to arrange their own pensions. libertarians argue against automatic enrolment as it impinges on an individual's freedom of choice. = = references = = = = external links = = https : / / web
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rates than when citizens are left to arrange their own pensions. libertarians argue against automatic enrolment as it impinges on an individual's freedom of choice. = = references = = = = external links = = https : / / web. archive. org / web / 20161118041846 / https : / / naeh. co. uk / national auto enrolment helpline
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in computing, terse rdf triple language ( turtle ) is a syntax and file format for expressing data in the resource description framework ( rdf ) data model. turtle syntax is similar to that of sparql, an rdf query language. it is a common data format for storing rdf data, along with n - triples, json - ld and rdf / xml. rdf represents information using semantic triples, which comprise a subject, predicate, and object. each item in the triple is expressed as a web uri. turtle provides a way to group three uris to make a triple, and provides ways to abbreviate such information, for example by factoring out common portions of uris. for example, information about huckleberry finn could be expressed as : < http : / / example. org / books / huckleberry _ finn > < http : / / example. org / relation / author > < http : / / example. org / person / mark _ twain >. = = history = = turtle was defined by dave beckett as a subset of tim berners - lee and dan connolly's notation3 ( n3 ) language, and a superset of the minimal n - triples format. unlike full n3, which has an expressive power that goes much beyond rdf, turtle can only serialize valid rdf graphs. turtle is an alternative to rdf / xml, the original syntax and standard for writing rdf. as opposed to rdf / xml, turtle does not rely on xml and is generally recognized as being more readable and easier to edit manually than its xml counterpart. sparql, the query language for rdf, uses a syntax similar to turtle for expressing query patterns. in 2011, a working group of the world wide web consortium ( w3c ) started working on an updated version of rdf, with the intention of publishing it along with a standardised version of turtle. this turtle specification was published as a w3c recommendation on 25 february 2014. a significant proportion of rdf toolkits include turtle parsing and serializing capability. some examples of such toolkits are redland, rdf4j, jena, python's rdflib and javascript's n3. js. = = example = = the following example defines 3 prefixes ( " rdf ", " dc ", and " ex " ), and uses them in expressing a statement about the editorship of the
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##script's n3. js. = = example = = the following example defines 3 prefixes ( " rdf ", " dc ", and " ex " ), and uses them in expressing a statement about the editorship of the rdf / xml document : ( turtle examples are also valid notation3 ). the example encodes an rdf graph made of four triples, which express these facts : the w3c technical report on rdf syntax and grammar has the title rdf / xml syntax specification ( revised ). that report's editor is a certain individual, who in turn has full name dave beckett. has a home page at a certain place. here are the triples made explicit in n - triples notation : the mime type of turtle is text / turtle. the character encoding of turtle content is always utf - 8. = = named graphs = = trig rdf syntax extends turtle with support for named graphs. = = see also = = n - triples notation3 ( n3 ) lv2 = = references = = = = external links = = turtle specification turtle tl ; dr cheatsheet on enola. dev
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the ecosystem approach is a conceptual framework for resolving ecosystem issues. the idea is to protect and manage the environment through the use of scientific reasoning. another point of the ecosystem approach is preserving the earth and its inhabitants from potential harm or permanent damage to the planet itself. with the preservation and management of the planet through an ecosystem approach, the future monetary and planetary gain are the by - product of sustaining and / or increasing the capacity of that particular environment. this is possible as the ecosystem approach incorporates humans, the economy, and ecology to the solution of any given problem. the initial idea for an ecosystem approach would come to light during the second meeting ( november 1995 ) at the conference of the parties ( cop ) it was the central topic in implementation and framework for the convention on biological diversity ( cbd ), it would further elaborate on the ecosystem approach as using varies methodologies for solving complex issues. throughout, the use and incorporation of ecosystem approaches, two similar terms have been created in that time : ecosystem - based management and ecosystem management. the convention on biological diversity has seen ecosystem - based management as a supporting topic / concept for the ecosystem approach. similarly, ecosystem management has a minor difference with the two terms. conceptual the differences between the three terms come from a framework structure and the different methods used in solving complex issues. the key component and definition between the three terms refer to the concept of conservation and protection of the ecosystem. the use of the ecosystem approach has been incorporated with managing water, land, and living organisms ecosystems and advocating the nourishment and sustainment of those ecological space. since the ecosystem approach is a conceptual model for solving problems, the key idea could combat various problems. = = history = = on december 29, 1993, the convention on biological diversity ( cbd ) was signed and applied as a multilateral treaty. with the purpose of achieving : biodiversity sustainability of species diversity endorse genetic diversity ( e. g. to maintain and endorses livestock, crops, and wildlife ) two years after the cbd was signed, during the second meeting of the conference of the parties ( november 1995 ) the representatives of the signed treaty would agree upon employing a strategy to combat the intricate and actively changing ecosystem. the ecosystem approach would represent as the equalizer for obtaining knowledge and creating countermeasures in preventing the endangerment of any ecological environment. with the acknowledgment of the ecosystem approach, during the fifth meeting of the conference of the parties, a group consensus agreed on a concrete definition and elaboration
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##measures in preventing the endangerment of any ecological environment. with the acknowledgment of the ecosystem approach, during the fifth meeting of the conference of the parties, a group consensus agreed on a concrete definition and elaboration for the ecosystem approach would be needed, and the parties would request subsidiary body on scientific technical and technological advice ( sbstta ) to create a guideline with 12 principles and a description of the ecosystem approach. the final results are given at cop 5 decision v / 6 summary. during the seventh meeting of the conference of the parties, further iteration on the ecosystem approach would be seen as a priority, during the meeting the parties would agree new implementation and strategical development could be incorporated with the ecosystem approach into the cbd. furthermore, creating a new relationship with sustaining forest organization and the ecosystem approach was talked about. all topics and discussion regarding seventh meeting are given at cop 7 decision vll / 11 summary. = = ecosystem approach and management = = with the development and use of the ecosystem approach, different variation to that form have been created and used. the two being ecosystem management and ecosystem - based management, the framework of the three methods are still the same ( the conservation and protection of the ecosystem ). the distinguishing part beings with how to initiate the approach of solving the problem. ecosystem - based management ( ebm ) is used for projects that incorporate interaction of different levels : organisms, the ecosystem, and the human component ; however, its varies from the other methods as the scale of the problem is larger and intricate. the objectives should be straightforward and condensed with important systematic information. also, ebm considers social and cultural aspects into the solution not just only scientific reasoning. with ecosystem management, the process is similar to ebm ; however, factors such as socioeconomics and politics can impact the decision and solution. a cultural aspect is also considered when creating a solution. = = ecosystem approach for self - reliance = = the ecosystem approach is currently being used in the fields of environmental and ocean management ( i. e. the ecosystem approach does not stop there ; it is being used in various fields and sub - fields as well ). the goal is to address the current problems facing those fields through the use of conceptual thinking and approach that would determine a viable and sustaining solution. one example, in particular, would be pertaining to fishery ( a commercial industry in capturing and selling of fishes ). in recent years, inland fisheries have quintupled from 2 million metric tons to 11 million metric tons in the span
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sustaining solution. one example, in particular, would be pertaining to fishery ( a commercial industry in capturing and selling of fishes ). in recent years, inland fisheries have quintupled from 2 million metric tons to 11 million metric tons in the span of 60 years from 1950 to 2010. through the use of the ecosystem approach more specifically the ecosystem approach to fisheries ( eaf ), sometimes referred to as ecosystem - based fisheries. eaf is seen as a framework to creating local strategies for each specific fishery ecosystem and implementing the new strategies gradually with the already existing rules and regulation. with the use of eaf if successful fishery industries could generate substantial income ; as well as, improve the fragile ecosystem of aquarium species. = = see also = = ecosystem convention on biological diversity the conference of the parties ecosystem management ecosystem - based management fishery ecosystem based fisheries = = references = =
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human ecosystems are human - dominated ecosystems of the anthropocene era that are viewed as complex cybernetic systems by conceptual models that are increasingly used by ecological anthropologists and other scholars to examine the ecological aspects of human communities in a way that integrates multiple factors as economics, sociopolitical organization, psychological factors, and physical factors related to the environment. a human ecosystem has three central organizing concepts : human environed unit ( an individual or group of individuals ), environment, interactions and transactions between and within the components. the total environment includes three conceptually distinct, but interrelated environments : the natural, human constructed, and human behavioral. these environments furnish the resources and conditions necessary for life and constitute a life - support system. = = further reading = = basso, keith 1996 “ wisdom sits in places : landscape and language among the western apache. ” albuquerque : university of new mexico press. douglas, mary 1999 “ implicit meanings : selected essays in anthropology. ” london and new york : routledge, taylor & francis group. nadasdy, paul 2003 “ hunters and bureaucrats : power, knowledge, and aboriginal - state relations in the southwest yukon. ” vancouver and toronto : ubc press. = = references = = = = see also = = media ecosystem urban ecosystem total human ecosystem
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in political science, a revolution ( latin : revolutio,'a turn around') is a rapid, fundamental transformation of a society's class, state, ethnic or religious structures. according to sociologist jack goldstone, all revolutions contain " a common set of elements at their core : ( a ) efforts to change the political regime that draw on a competing vision ( or visions ) of a just order, ( b ) a notable degree of informal or formal mass mobilization, and ( c ) efforts to force change through noninstitutionalized actions such as mass demonstrations, protests, strikes, or violence. " revolutions have occurred throughout human history and varied in their methods, durations and outcomes. some revolutions started with peasant uprisings or guerrilla warfare on the periphery of a country ; others started with urban insurrection aimed at seizing the country's capital city. revolutions can be inspired by the rising popularity of certain political ideologies, moral principles, or models of governance such as nationalism, republicanism, egalitarianism, self - determination, human rights, democracy, liberalism, fascism, or socialism. a regime may become vulnerable to revolution due to a recent military defeat, or economic chaos, or an affront to national pride and identity, or persistent repression and corruption. revolutions typically trigger counter - revolutions which seek to halt revolutionary momentum, or to reverse the course of an ongoing revolutionary transformation. notable revolutions in recent centuries include the american revolution ( 1765 – 1783 ), french revolution ( 1789 – 1799 ), haitian revolution ( 1791 – 1804 ), spanish american wars of independence ( 1808 – 1826 ), revolutions of 1848 in europe, mexican revolution ( 1910 – 1920 ), xinhai revolution in china in 1911, revolutions of 1917 – 1923 in europe ( including the russian revolution and german revolution ), chinese communist revolution ( 1927 – 1949 ), decolonization of africa ( mid - 1950s to 1975 ), algerian war of independence ( 1954 - 1962 ), cuban revolution in 1959, iranian revolution and nicaraguan revolution in 1979, worldwide revolutions of 1989, and arab spring in the early 2010s. = = etymology = = the french noun revolucion traces back to the 13th century, and the english equivalent " revolution " to the late 14th century. the word was limited then to mean the revolving motion of celestial bodies. " revolution " in the sense of abrupt change in a social order was first recorded in the mid - 15th century. by 1688, the political meaning of the word was familiar enough that the replacement of james
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then to mean the revolving motion of celestial bodies. " revolution " in the sense of abrupt change in a social order was first recorded in the mid - 15th century. by 1688, the political meaning of the word was familiar enough that the replacement of james ii with william iii was termed the " glorious revolution ". = = definition = = " revolution " is now employed most often to denote a change in social and political institutions. jeff goodwin offers two definitions. first, a broad one, including " any and all instances in which a state or a political regime is overthrown and thereby transformed by a popular movement in an irregular, extraconstitutional or violent fashion ". second, a narrow one, in which " revolutions entail not only mass mobilization and regime change, but also more or less rapid and fundamental social, economic or cultural change, during or soon after the struggle for state power ". jack goldstone defines a revolution thusly : " [ revolution is ] an effort to transform the political institutions and the justifications for political authority in society, accompanied by formal or informal mass mobilization and noninstitutionalized actions that undermine authorities. this definition is broad enough to encompass events ranging from the relatively peaceful revolutions that toppled communist regimes to the violent islamic revolution in afghanistan. at the same time, this definition is strong enough to exclude coups, revolts, civil wars, and rebellions that make no effort to transform institutions or the justification for authority. " goldstone's definition excludes peaceful transitions to democracy through plebiscite or free elections, as occurred in spain after the death of francisco franco, or in argentina and chile after the demise of their military juntas. early scholars often debated the distinction between revolution and civil war. they also questioned whether a revolution is purely political ( i. e., concerned with the restructuring of government ) or whether " it is an extensive and inclusive social change affecting all the various aspects of the life of a society, including the economic, religious, industrial, and familial as well as the political ". = = types = = there are numerous typologies of revolution in the social science literature. alexis de tocqueville differentiated between : sudden and violent revolutions that seek not only to establish a new political system but to overhaul an entire society, and ; slow and relentless revolutions that involve sweeping transformations of the entire society and may take several generations to bring about ( such as changes in religion ). one of the marxist typologies divides revolutions into : pre
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but to overhaul an entire society, and ; slow and relentless revolutions that involve sweeping transformations of the entire society and may take several generations to bring about ( such as changes in religion ). one of the marxist typologies divides revolutions into : pre - capitalist early bourgeois bourgeois bourgeois - democratic early proletarian socialist charles tilly, a modern scholar of revolutions, differentiated between : coup d'etat ( a top - down seizure of power ), e. g., poland, 1926 civil war revolt, and " great revolution " ( a revolution that transforms economic and social structures as well as political institutions, such as the french revolution of 1789, russian revolution of 1917, or islamic revolution of iran in 1979 ). mark katz identified six forms of revolution : rural revolution urban revolution coup d'etat, e. g., egypt, 1952 revolution from above, e. g., mao zedong's great leap forward of 1958 revolution from without, e. g., the allied invasions of italy in 1943 and of germany in 1945 revolution by osmosis, e. g., the gradual islamization of several countries. these categories are not mutually exclusive ; the russian revolution of 1917 began with an urban revolution to depose the czar, followed by a rural revolution, followed by the bolshevik coup in november. katz also cross - classified revolutions as follows : central : countries, usually great powers, which play a leading role in a revolutionary wave ; e. g., the ussr, nazi germany, iran since 1979 aspiring revolutions, which follow the central revolution subordinate or puppet revolutions rival revolutions, in which a former alliance is broken, such as yugoslavia after 1948, and china after 1960. a further dimension to katz's typology is that revolutions are either against ( anti - monarchy, anti - dictatorial, anti - communist, anti - democratic ) or for ( pro - fascism, pro - communism, pro - nationalism, etc. ). in the latter cases, a transition period is generally necessary to decide which direction to take to achieve the desired form of government. other types of revolution, created for other typologies, include proletarian or communist revolutions ( inspired by the ideas of marxism that aim to replace capitalism with communism ) ; failed or abortive revolutions ( that are not able to secure power after winning temporary victories or amassing large - scale mobilizations ) ; or violent vs. nonviolent revolutions. the term revolution has also been used to denote great changes outside the political sphere. such revolutions, often
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that are not able to secure power after winning temporary victories or amassing large - scale mobilizations ) ; or violent vs. nonviolent revolutions. the term revolution has also been used to denote great changes outside the political sphere. such revolutions, often labeled social revolutions, are recognized as major transformations in a society's culture, philosophy, or technology, rather than in its political system. some social revolutions are global in scope, while others are limited to single countries. commonly cited examples of social revolution are the industrial revolution, scientific revolution, commercial revolution, and digital revolution. these revolutions also fit the " slow revolution " type identified by tocqueville. = = studies of revolution = = political and socioeconomic revolutions have been studied in many social sciences, particularly sociology, political science and history. scholars of revolution differentiate four generations of theoretical research on the subject of revolution. theorists of the first generation, including gustave le bon, charles a. ellwood, and pitirim sorokin, were mainly descriptive in their approach, and their explanations of the phenomena of revolutions were usually related to social psychology, such as le bon's crowd psychology theory. the second generation sought to develop detailed frameworks, grounded in social behavior theory, to explain why and when revolutions arise. their work can be divided into three categories : psychological, sociological and political. the writings of ted robert gurr, ivo k. feierbrand, rosalind l. feierbrand, james a. geschwender, david c. schwartz, and denton e. morrison fall into the first category. they utilized theories of cognitive psychology and frustration - aggression theory to link the cause of revolution to the state of mind of the masses. while these theorists varied in their approach as to what exactly incited the people to revolt ( e. g., modernization, recession, or discrimination ), they agreed that the primary cause for revolution was a widespread frustration with the socio - political situation. the second group, composed of academics such as chalmers johnson, neil smelser, bob jessop, mark hart, edward a. tiryakian, and mark hagopian, drew on the work of talcott parsons and the structural - functionalist theory in sociology. they saw society as a system in equilibrium between various resources, demands, and subsystems ( political, cultural, etc. ). as in the psychological school, they differed in their definitions of what causes disequilibrium, but agreed that it is a state of severe disequilibrium that
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, demands, and subsystems ( political, cultural, etc. ). as in the psychological school, they differed in their definitions of what causes disequilibrium, but agreed that it is a state of severe disequilibrium that is responsible for revolutions. the third group, including writers such as charles tilly, samuel p. huntington, peter ammann, and arthur l. stinchcombe, followed a political science path and looked at pluralist theory and interest group conflict theory. those theories view events as outcomes of a power struggle between competing interest groups. in such a model, revolutions happen when two or more groups cannot come to terms within the current political system's normal decision - making process, and when they possess the required resources to employ force in pursuit of their goals. the second - generation theorists regarded the development of revolutionary situations as a two - step process : " first, a pattern of events arises that somehow marks a break or change from previous patterns. this change then affects some critical variable — the cognitive state of the masses, the equilibrium of the system, or the magnitude of conflict and resource control of competing interest groups. if the effect on the critical variable is of sufficient magnitude, a potentially revolutionary situation occurs. " once this point is reached, a negative incident ( a war, a riot, a bad harvest ) that in the past might not have been enough to trigger a revolt, will now be enough. however, if authorities are cognizant of the danger, they can still prevent revolution through reform or repression. in his influential 1938 book the anatomy of revolution, historian crane brinton established a convention by choosing four major political revolutions — england ( 1642 ), thirteen colonies of america ( 1775 ), france ( 1789 ), and russia ( 1917 ) — for comparative study. he outlined what he called their " uniformities ", although the american revolution deviated somewhat from the pattern. as a result, most later comparative studies of revolution substituted china ( 1949 ) in their lists, but they continued brinton's practice of focusing on four. in subsequent decades, scholars began to classify hundreds of other events as revolutions ( see list of revolutions and rebellions ). their expanded notion of revolution engendered new approaches and explanations. the theories of the second generation came under criticism for being too limited in geographical scope, and for lacking a means of empirical verification. also, while second - generation theories may have been capable of explaining a specific revolution, they could not adequately explain why revolutions failed to occur in other
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generation came under criticism for being too limited in geographical scope, and for lacking a means of empirical verification. also, while second - generation theories may have been capable of explaining a specific revolution, they could not adequately explain why revolutions failed to occur in other societies experiencing very similar circumstances. the criticism of the second generation led to the rise of a third generation of theories, put forth by writers such as theda skocpol, barrington moore, jeffrey paige, and others expanding on the old marxist class - conflict approach. they turned their attention to " rural agrarian - state conflicts, state conflicts with autonomous elites, and the impact of interstate economic and military competition on domestic political change. " in particular, skocpol's states and social revolutions ( 1979 ) was a landmark book of the third generation. skocpol defined revolution as " rapid, basic transformations of society's state and class structures... accompanied and in part carried through by class - based revolts from below ", and she attributed revolutions to " a conjunction of multiple conflicts involving state, elites and the lower classes ". in the late 1980s, a new body of academic work started questioning the dominance of the third generation's theories. the old theories were also dealt a significant blow by a series of revolutionary events that they could not readily explain. the iranian and nicaraguan revolutions of 1979, the 1986 people power revolution in the philippines, and the 1989 autumn of nations in europe, asia and africa saw diverse opposition movements topple seemingly powerful regimes amidst popular demonstrations and mass strikes in nonviolent revolutions. for some historians, the traditional paradigm of revolutions as class struggle - driven conflicts centered in europe, and involving a violent state versus its discontented people, was no longer sufficient to account for the multi - class coalitions toppling dictators around the world. consequently, the study of revolutions began to evolve in three directions. as goldstone describes it, scholars of revolution : extended the third generation's structural theories to a more heterogeneous set of cases, " well beyond the small number of'great'social revolutions ". called for greater attention to conscious agency and contingency in understanding the course and outcome of revolutions. observed how studies of social movements — for women's rights, labor rights, and u. s. civil rights — had much in common with studies of revolution and could enrich the latter. thus, " a new literature on'contentious politics'has developed that attempts to combine insights from the literature on social movements and revolutions to better understand both phenomena
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. civil rights — had much in common with studies of revolution and could enrich the latter. thus, " a new literature on'contentious politics'has developed that attempts to combine insights from the literature on social movements and revolutions to better understand both phenomena. " the fourth generation increasingly turned to quantitative techniques when formulating its theories. political science research moved beyond individual or comparative case studies towards large - n statistical analysis assessing the causes and implications of revolution. the initial fourth - generation books and journal articles generally relied on the polity data series on democratization. such analyses, like those by a. j. enterline, zeev maoz, and edward d. mansfield and jack snyder, identified a revolution by a significant change in the country's score on polity's autocracy - to - democracy scale. since the 2010s, scholars like jeff colgan have argued that the polity data series — which evaluates the degree of democratic or autocratic authority in a state's governing institutions based on the openness of executive recruitment, constraints on executive authority, and political competition — is inadequate because it measures democratization, not revolution, and doesn't account for regimes which come to power by revolution but fail to change the structure of the state and society sufficiently to yield a notable difference in the polity score. instead, colgan offered a new data set to single out governments that " transform the existing social, political, and economic relationships of the state by overthrowing or rejecting the principal existing institutions of society. " this data set has been employed to make empirically based contributions to the literature on revolution by finding links between revolution and the likelihood of international disputes. revolutions have been further examined from an anthropological perspective. drawing on victor turner's writings on ritual and performance, bjorn thomassen suggested that revolutions can be understood as " liminal " moments : modern political revolutions very much resemble rituals and can therefore be studied within a process approach. this would imply not only a focus on political behavior " from below ", but also a recognition of moments where " high and low " are relativized, subverted, or made irrelevant, and where the micro and macro levels fuse together in critical conjunctions. economist douglass north raised a note of caution about revolutionary change, how it " is never as revolutionary as its rhetoric would have us believe ". while the " formal rules " of laws and constitutions can be changed virtually overnight, the " informal constraints " such as institutional inertia and cultural inheritance do not change quickly and thereby slow down
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as revolutionary as its rhetoric would have us believe ". while the " formal rules " of laws and constitutions can be changed virtually overnight, the " informal constraints " such as institutional inertia and cultural inheritance do not change quickly and thereby slow down the societal transformation. according to north, the tension between formal rules and informal constraints is " typically resolved by some restructuring of the overall constraints — in both directions — to produce a new equilibrium that is far less revolutionary than the rhetoric. " = = see also = = = = references = = = = = bibliography = = = fukuyama, francis ( 1992 ). the end of history and the last man. penguin. isbn 978 - 0 - 140 - 13455 - 1. getachew, adom ( 2019 ). worldmaking after empire : the rise and fall of self - determination. princeton university press. isbn 978 - 0 - 691 - 17915 - 5. gunitsky, seva ( 2017 ). aftershocks. princeton university press. isbn 978 - 0 - 691 - 17233 - 0. gunitsky, seva ( 2018 ). " democratic waves in historical perspective ". perspectives on politics. 16 ( 3 ) : 634 – 651. doi : 10. 1017 / s1537592718001044. issn 1537 - 5927. s2cid 149523316. gunitsky, seva ( 2021 ), bartel, fritz ; monteiro, nuno p. ( eds. ), " great powers and the spread of autocracy since the cold war ", before and after the fall : world politics and the end of the cold war, cambridge university press, pp. 225 – 243, doi : 10. 1017 / 9781108910194. 014, isbn 978 - 1 - 108 - 84334 - 8, s2cid 244851964 katz, mark n. ( 1997 ). revolutions and revolutionary waves. st martin's press. isbn 978 - 0 - 312 - 17322 - 7. peter kropotkin ( 1906 ), memoirs of a revolutionist. london : swan sonnenschein & co., ltd. reus - smit, christian ( 2013 ). individual rights and the making of the international system. cambridge university press. doi : 10. 1017 / cbo9781139046527. isbn 978 - 0 - 521 - 85777 - 2.
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2013 ). individual rights and the making of the international system. cambridge university press. doi : 10. 1017 / cbo9781139046527. isbn 978 - 0 - 521 - 85777 - 2. = = further reading = = beissinger, mark r. 2022. the revolutionary city : urbanization and the global transformation of rebellion. princeton university press beissinger, mark r. ( 2024 ). " the evolving study of revolution ". world politics. beck, colin j. ( 2018 ). " the structure of comparison in the study of revolution ". sociological theory. 36 ( 2 ) : 134 – 161. doi : 10. 1177 / 0735275118777004. s2cid 53669466. edelstein, dan ( 2025 ). the revolution to come : a history of an idea from thucydides to lenin. princeton university press. isbn 9780691231853. goldstone, jack a. ( 1982 ). " the comparative and historical study of revolutions ". annual review of sociology. 8 : 187 – 207 ness, immanuel, ed. ( 2009 ). the international encyclopedia of revolution and protest : 1500 to the present. malden, ma : wiley & sons. isbn 978 - 1 - 405 - 18464 - 9. strang, david ( 1991 ). " global patterns of decolonization, 1500 - 1987 ". international studies quarterly. 35 ( 4 ) : 429 – 454. doi : 10. 2307 / 2600949. issn 0020 - 8833. jstor 2600949. = = external links = = arendt, hannah ( 1963 ). iep. utm. edu. on revolution. penguin classics. new ed edition : february 8, 1991. isbn 0 - 14 - 018421 - x.
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bayes linear statistics is a subjectivist statistical methodology and framework. traditional subjective bayesian analysis is based upon fully specified probability distributions, which are very difficult to specify at the necessary level of detail. bayes linear analysis attempts to solve this problem by developing theory and practise for using partially specified probability models. bayes linear in its current form has been primarily developed by michael goldstein. mathematically and philosophically it extends bruno de finetti's operational subjective approach to probability and statistics. = = motivation = = consider first a traditional bayesian analysis where you expect to shortly know d and you would like to know more about some other observable b. in the traditional bayesian approach it is required that every possible outcome is enumerated i. e. every possible outcome is the cross product of the partition of a set of b and d. if represented on a computer where b requires n bits and d m bits then the number of states required is 2 n + m { \ displaystyle 2 ^ { n + m } }. the first step to such an analysis is to determine a person's subjective probabilities e. g. by asking about their betting behaviour for each of these outcomes. when we learn d conditional probabilities for b are determined by the application of bayes'rule. practitioners of subjective bayesian statistics routinely analyse datasets where the size of this set is large enough that subjective probabilities cannot be meaningfully determined for every element of d × b. this is normally accomplished by assuming exchangeability and then the use of parameterized models with prior distributions over parameters and appealing to the de finetti's theorem to justify that this produces valid operational subjective probabilities over d × b. the difficulty with such an approach is that the validity of the statistical analysis requires that the subjective probabilities are a good representation of an individual's beliefs however this method results in a very precise specification over d × b and it is often difficult to articulate what it would mean to adopt these belief specifications. in contrast to the traditional bayesian paradigm bayes linear statistics following de finetti uses prevision or subjective expectation as a primitive, probability is then defined as the expectation of an indicator variable. instead of specifying a subjective probability for every element in the partition d × b the analyst specifies subjective expectations for just a few quantities that they are interested in or feel knowledgeable about. then instead of conditioning an adjusted expectation is computed by a rule that is a generalization of bayes'rule that is
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the partition d × b the analyst specifies subjective expectations for just a few quantities that they are interested in or feel knowledgeable about. then instead of conditioning an adjusted expectation is computed by a rule that is a generalization of bayes'rule that is based upon expectation. the use of the word linear in the title refers to de finetti's arguments that probability theory is a linear theory ( de finetti argued against the more common measure theory approach ). = = example = = in bayes linear statistics, the probability model is only partially specified, and it is not possible to calculate conditional probability by bayes'rule. instead bayes linear suggests the calculation of an adjusted expectation. to conduct a bayes linear analysis it is necessary to identify some values that you expect to know shortly by making measurements d and some future value which you would like to know b. here d refers to a vector containing data and b to a vector containing quantities you would like to predict. for the following example b and d are taken to be two - dimensional vectors i. e. b = ( y 1, y 2 ), d = ( x 1, x 2 ). { \ displaystyle b = ( y _ { 1 }, y _ { 2 } ), ~ d = ( x _ { 1 }, x _ { 2 } ). } in order to specify a bayes linear model it is necessary to supply expectations for the vectors b and d, and to also specify the correlation between each component of b and each component of d. for example the expectations are specified as : e ( y 1 ) = 5, e ( y 2 ) = 3, e ( x 1 ) = 5, e ( x 2 ) = 3 { \ displaystyle e ( y _ { 1 } ) = 5, ~ e ( y _ { 2 } ) = 3, ~ e ( x _ { 1 } ) = 5, ~ e ( x _ { 2 } ) = 3 } and the covariance matrix is specified as : x 1 x 2 y 1 y 2 x 1 1 u γ γ x 2 u 1 γ γ y 1 γ γ 1 v y 2 γ γ v 1. { \ displaystyle { \ begin { array } { c | cccc } & x _ { 1 } & x _ { 2 } & y _ { 1 } & y _ { 2 } \ \ \ hline x _ { 1 } & 1 & u & \ gamma & \ gamma \ \ x _ { 2 } &
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_ { 1 } & x _ { 2 } & y _ { 1 } & y _ { 2 } \ \ \ hline x _ { 1 } & 1 & u & \ gamma & \ gamma \ \ x _ { 2 } & u & 1 & \ gamma & \ gamma \ \ y _ { 1 } & \ gamma & \ gamma & 1 & v \ \ y _ { 2 } & \ gamma & \ gamma & v & 1 \ \ \ end { array } }. } the repetition in this matrix, has some interesting implications to be discussed shortly. an adjusted expectation is a linear estimator of the form c 0 + c 1 x 1 + c 2 x 2 { \ displaystyle c _ { 0 } + c _ { 1 } x _ { 1 } + c _ { 2 } x _ { 2 } } where c 0, c 1 { \ displaystyle c _ { 0 }, c _ { 1 } } and c 2 { \ displaystyle c _ { 2 } } are chosen to minimise the prior expected loss for the observations i. e. y 1, y 2 { \ displaystyle y _ { 1 }, y _ { 2 } } in this case. that is for y 1 { \ displaystyle y _ { 1 } } e ( [ y 1 − c 0 − c 1 x 1 − c 2 x 2 ] 2 ) { \ displaystyle e ( [ y _ { 1 } - c _ { 0 } - c _ { 1 } x _ { 1 } - c _ { 2 } x _ { 2 } ] ^ { 2 } ) \, } where c 0, c 1, c 2 { \ displaystyle c _ { 0 }, c _ { 1 }, c _ { 2 } \, } are chosen in order to minimise the prior expected loss in estimating y 1 { \ displaystyle y _ { 1 } } in general the adjusted expectation is calculated with e d ( x ) = i = 0 k h i d i. { \ displaystyle e _ { d } ( x ) = \ sum _ { i = 0 } ^ { k } h _ { i } d _ { i }. } setting h 0, …, h k { \ displaystyle h _ { 0 }, \ dots, h _ { k } } to minimise from a proof provided in ( goldstein and wooff 2007 ) it can be shown that : e d ( x ) = e ( x
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k { \ displaystyle h _ { 0 }, \ dots, h _ { k } } to minimise from a proof provided in ( goldstein and wooff 2007 ) it can be shown that : e d ( x ) = e ( x ) + c o v ( x, d ) v a r ( d ) − 1 ( d − e ( d ) ). { \ displaystyle e _ { d } ( x ) = e ( x ) + \ mathrm { cov } ( x, d ) \ mathrm { var } ( d ) ^ { - 1 } ( d - e ( d ) ). \, } for the case where var ( d ) is not invertible the moore – penrose pseudoinverse should be used instead. furthermore, the adjusted variance of the variable x after observing the data d is given by v a r d ( x ) = v a r ( x ) − c o v ( x, d ) v a r ( d ) − 1 c o v ( d, x ). { \ displaystyle \ mathrm { var } _ { d } ( x ) = \ mathrm { var } ( x ) - \ mathrm { cov } ( x, d ) \ mathrm { var } ( d ) ^ { - 1 } \ mathrm { cov } ( d, x ). } = = see also = = imprecise probability = = external links = = bayes linear methods = = references = = goldstein, m. ( 1981 ) revising previsions : a geometric interpretation ( with discussion ). journal of the royal statistical society, series b, 43 ( 2 ), 105 - 130 goldstein, m. ( 2006 ) subjectivism principles and practice. bayesian analysis ] [ 1 ] michael goldstein, david wooff ( 2007 ) bayes linear statistics, theory & methods, wiley. isbn 978 - 0 - 470 - 01562 - 9 de finetti, b. ( 1931 ) " probabilism : a critical essay on the theory of probability and on the value of science, " ( translation of 1931 article ) in erkenntnis, volume 31, september 1989. the entire double issue is devoted to de finetti's philosophy of probability. de finetti, b. ( 1937 ) “ la prevision : ses lois logiques, ses sources subjectives, ” annales de l'institut henri poincare, - " foresight : its logical laws,
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of probability. de finetti, b. ( 1937 ) “ la prevision : ses lois logiques, ses sources subjectives, ” annales de l'institut henri poincare, - " foresight : its logical laws, its subjective sources, " ( translation of the 1937 article in french ) in h. e. kyburg and h. e. smokler ( eds ), studies in subjective probability, new york : wiley, 1964. de finetti, b. ( 1974 ) theory of probability, ( translation by a machi and afm smith of 1970 book ) 2 volumes, new york : wiley, 1974 - 5.
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reproductive value is a concept in demography and population genetics that represents the discounted number of future female children that will be born to a female of a specific age. ronald fisher first defined reproductive value in his 1930 book the genetical theory of natural selection where he proposed that future offspring be discounted at the rate of growth of the population ; this implies that sexually reproductive value measures the contribution of an individual of a given age to the future growth of the population. = = definition = = consider a species with a life history table with survival and reproductive parameters given by ℓ x { \ displaystyle \ ell _ { x } } and m x { \ displaystyle m _ { x } }, where ℓ x { \ displaystyle \ ell _ { x } } = probability of surviving from age 0 to age x { \ displaystyle x } and m x { \ displaystyle m _ { x } } = average number of offspring produced by an individual of age x. { \ displaystyle x. } in a population with a discrete set of age classes, fisher's reproductive value is calculated as v x = y = x ∞ λ − ( y − x + 1 ) ℓ y ℓ x m y { \ displaystyle v _ { x } = \ sum _ { y = x } ^ { \ infty } \ lambda ^ { - ( y - x + 1 ) } { \ frac { \ ell _ { y } } { \ ell _ { x } } } m _ { y } } where λ { \ displaystyle \ lambda } is the long - term population growth rate given by the dominant eigenvalue of the leslie matrix. when age classes are continuous, v ( x ) = x ∞ e − r ( y − x ) ℓ ( y ) ℓ ( x ) m ( y ) d y { \ displaystyle v ( x ) = \ int _ { x } ^ { \ infty } e ^ { - r ( y - x ) } { \ frac { \ ell ( y ) } { \ ell ( x ) } } m ( y ) dy } where r { \ displaystyle r } is the intrinsic rate of increase or malthusian growth rate. = = see also = = population dynamics euler – lotka equation leslie matrix senescence = = notes = = fisher, r. a. 1930. the genetical theory of natural selection. oxford university press, oxford. keyfitz, n
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= = see also = = population dynamics euler – lotka equation leslie matrix senescence = = notes = = fisher, r. a. 1930. the genetical theory of natural selection. oxford university press, oxford. keyfitz, n. and caswell, h. 2005. applied mathematical demography. springer, new york. 3rd edition. doi : 10. 1007 / b139042 = = references = =
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a sudden stop in capital flows is defined as a sudden slowdown in private capital inflows into emerging market economies, and a corresponding sharp reversal from large current account deficits into smaller deficits or small surpluses. sudden stops are usually followed by a sharp decrease in output, private spending and credit to the private sector, and real exchange rate depreciation. the term " sudden stop " was inspired by a banker ’ s comment on a paper by rudiger dornbusch and alejandro werner about mexico, that " it is not speed that kills, it is the sudden stop. " sudden stops are commonly described as periods that contain at least one observation where the year - on - year fall in capital flows lies at least two standard deviations below its sample mean. the start of the sudden stop period is determined by the first time the annual change in capital flows falls one standard deviation below the mean and the end of the sudden stop period is determined once the annual change in capital flows exceeds one standard deviation below its sample mean. = = economic impact = = the balance of payments identity establishes that the current account is equal to the capital account plus the accumulation of international reserves. therefore, a large slowdown in capital inflows is met either by a loss of international reserves and / or a lower current account deficit, both of which have negative economic effects. a reduction in the current account deficit is achieved through a decrease in domestic aggregate demand for tradable goods. since tradable and non - tradable goods are complements, this also reduces demand for non - tradable goods. the demand for tradable goods reflects in a reduction in imports ; however, the lower demand for non - tradable goods translates into lower output and real depreciation of the currency ( lower relative price of non tradable to tradable goods ). firms producing non - tradable goods face an increase in the real cost of financing, as the cost of loans in terms of the price of non - tradable goods rises. these firms get lower revenues, which reduce their ability to repay their loans. as a result, banks face a higher rate of non - performing loans from this sector. in this situation, banks become more cautious and decrease loans, which worsens the economic recession. a collapse in asset prices also contributes to a sharp slowdown in economic activity. the value of loan collaterals are severely reduced which further impacts the situation of the financial system and reduces credit, reflecting in lower consumption and investment.
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##ns the economic recession. a collapse in asset prices also contributes to a sharp slowdown in economic activity. the value of loan collaterals are severely reduced which further impacts the situation of the financial system and reduces credit, reflecting in lower consumption and investment. furthermore, lower asset prices have negative wealth effects for consumers, which further reduce consumption spending. the features of sudden stops are similar to those of balance of payment crises in terms of devaluations of the domestic currency followed by periods of output loss. however, sudden stops are characterized by sharper recessions and a larger fall in the price of non - tradable to tradable goods. a similar argument relates large changes in relative prices of tradable and non - tradable goods with the effects of a sudden stop. the mechanism is explained by a credit based approach to currency crises, where countries with less developed financial markets experience a sharper output fall during a sudden stop episode, regardless of whether the country has a fixed or floating exchange rate regime, as the source of the crisis is through the deterioration of private firms ’ balance sheets. therefore, a higher proportion of foreign currency debt increases the vulnerability to currency devaluations. different to first generation crisis models, in their model crises may occur even under low unemployment and sound fiscal policies. an additional effect of sudden stops and third generation crises in emerging markets are related to financial institutions and sudden stops in short term capital inflows, in comparison to previous crises where the main features were related to fiscal imbalances or weakness in real activity. in this type of model, international financial markets play a key role, where small open economies face a problem of international illiquidity during the crisis episodes, associated with the collapse of the financial system. due to the inherent structure of the banking system, banks transform maturity from liquid deposits to illiquid assets, which creates vulnerability to bank runs. even in situations where banks might be solvent, in the short run bank runs create an illiquidity problem, where banks would need to borrow funds to meet the temporary deposit withdrawals. however, under this situation, it might be harder to obtain foreign funds, as foreign creditors may also panic depending on the degree of commitment to repay international debts. moreover, the higher the level of short term debt the higher the exposure to illiquidity problems. this models is particularly related to the situation in emerging markets, because of the larger role of banks compared to other financial institutions in these economies and because it is more difficult for them to get emergency
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debt the higher the exposure to illiquidity problems. this models is particularly related to the situation in emerging markets, because of the larger role of banks compared to other financial institutions in these economies and because it is more difficult for them to get emergency funds from world markets during crisis periods. an alternative explanation of sudden stops focuses on the interaction of temporary and permanent technology shocks, where highly volatile trend shocks in emerging market economies are closely related to sudden stop episodes. emerging markets are characterized by frequent regime switches related to changes in fiscal, monetary and trade policies, which reflect in more volatile shocks to the trend. the sharp effects of sudden stop episodes are not only related to the large magnitude of the shock, but also to the fact that there is a negative productivity shock with a change in trend. in order to study sudden stop episodes, using data from the 1994 economic crisis in mexico, this model decomposes it to obtain a representation of transitory and permanent technology shocks. the results show that including permanent technology shocks is able to produce the behavior observed during a sudden stop episode. the model predicts a large contraction in output, consumption and investment, as well as a sharp current account reversal. = = empirical issues = = empirical studies mention a group of indicators that may be related to sudden stops. the composition of capital inflows, with a higher proportion of short term financing may be more risky as they generate larger slowdowns in capital inflows. the time profile of maturity debt is important in assessing the potential for sudden reversals in capital flows. the shorter the maturity of a country ’ s debt, the more prone it is for a sudden stop crises. = = = emerging markets = = = some empirical studies focus on the interaction between sudden stops and financial crises in emerging market economies. using a sample of emerging market countries with large capital inflows from latin america, asia and europe, they compare the severity of the sudden stop episodes associated with currency crises and banking crises. the severity of sudden stop episodes in emerging market economies are compared using indicators such as the real depreciation of the currency and indicators of currency and banking crises. results suggest that currency and banking crises in asia in 1995 - 1997 were more severe than the sharpest crises in latin america, in terms of banking bailout costs and the size of capital account reversal. also, emerging economies are more exposed to suffer this type of crisis as well as current - account reversals. another topic of study is the impact of sudden stops on output. sudden stops can be accompanied by a
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and the size of capital account reversal. also, emerging economies are more exposed to suffer this type of crisis as well as current - account reversals. another topic of study is the impact of sudden stops on output. sudden stops can be accompanied by a currency crisis and / or a banking crisis. empirical studies show that the effects of a banking crisis are more pernicious than the effects of a currency crisis, due to the additional effect of the credit channel on output. lower asset prices are a persistent fact after a banking crisis, which indicate a low value of collaterals to loans, and therefore, negatively impact the banking sector and the supply of loans. regarding exports, currency crises show a faster recovery in the export sector, while exports remain low for an average of two years after banking crises. banking crises also present a sharper recession, consistent with the disruption of the financial sector. there is a distinguishable boom – bust cycle, as unsustainable massive capital inflows that precede a sudden stop episode sharply increase economic activity. = = = emerging markets and advanced economies = = = other studies focus on the relationship between current account reversals and sudden stops in both emerging markets and advanced economies. using cross - country data for a sample of 157 countries during the 1970 - 2001 period, the results indicate that 46. 1 % of countries that suffered a sudden stop also faced a current account reversal, while 22. 9 % of countries that faced current account reversals also faced a sudden stop episode. the less - than - one relationship could be related to an effective use of international reserves to offset capital outflows during sudden stops, while during current account reversals, there are some countries that were not receiving large capital inflows, so their deficits were financed through a loss of international reserves. a comparison of the stylized facts observed during sudden stop episodes in emerging market economies and developed countries on the financial crises of the 1990s relate sudden stops in emerging market and advanced economies with the presence of contagion effects. most sudden stop episodes for emerging markets occur around the tequila ( 1994 ), east asian ( 1997 ) and russian ( 1998 ) crises. in the case of developed economies, sudden stop episodes occur around the european exchange rate mechanism ( erm ) ( 1992 – 1993 ) crisis. = = policy measures = = regarding policy measures adopted during sudden stop episodes, the massive slowdown in capital inflows, usually presented as large capital outflows, can be counteracted by exchange rate devaluation, loss of international reserves and
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= policy measures = = regarding policy measures adopted during sudden stop episodes, the massive slowdown in capital inflows, usually presented as large capital outflows, can be counteracted by exchange rate devaluation, loss of international reserves and / or increases in real interest rates. the nominal exchange rate behavior during most sudden stop episodes show that sudden stops in emerging markets are followed by a devaluation of the domestic currency, while most depreciation episodes in developed countries are not related to sudden stop phases. real interest rates sharply increase during sudden stop episodes, especially in the case of emerging market economies. a sharp loss of international reserves is also observed during sudden stop episodes, both in developed countries and emerging markets. the current account balance shows a sharp reduction in current account deficits, with a significantly higher increase in the current account balance in emerging markets. = = see also = = balance of payments bank run capital flight currency crisis domestic liability dollarization financial crisis sovereign default = = references = =
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the sheepeater cliffs are a series of exposed cliffs made up of columnar basalt in yellowstone national park in the united states. the lava was deposited about 500, 000 years ago during one of the periodic basaltic floods in yellowstone caldera, and later exposed by the gardner river. the cliffs are noted as a textbook example of a basaltic flow with well defined joints and hexagonal columns. they were named after a band of eastern shoshone known as tukuaduka ( sheep eaters ). many of the exposed cliffs are located along a steep inaccessible canyon cut by the gardner near bunsen peak, but some of the cliffs located just off the grand loop road can be reached by car. = = references = = = = external links = = national park service video – sheepeater cliffs
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immunomagnetic separation ( ims ) is a laboratory tool that can efficiently isolate cells out of body fluid or cultured cells. it can also be used as a method of quantifying the pathogenicity of food, blood or feces. dna analysis have supported the combined use of both this technique and polymerase chain reaction ( pcr ). another laboratory separation tool is the affinity magnetic separation ( ams ), which is more suitable for the isolation of prokaryotic cells. ims deals with the isolation of cells, proteins, and nucleic acids through the specific capture of biomolecules through the attachment of small - magnetized particles, beads, containing antibodies and lectins. these beads are coated to bind to targeted biomolecules, gently separated and goes through multiple cycles of washing to obtain targeted molecules bound to these super paramagnetic beads, which can differentiate based on strength of magnetic field and targeted molecules, are then eluted to collect supernatant and then are able to determine the concentration of specifically targeted biomolecules. ims obtains certain concentrations of specific molecules within targeted bacteria. a mixture of cell population will be put into a magnetic field where cells then are attached to super paramagnetic beads, specific example are dynabeads ( 4. 5 - μm ), will remain once excess substrate is removed binding to targeted antigen. dynabeads consists of iron - containing cores, which is covered by a thin layer of a polymer shell allowing the absorption of biomolecules. the beads are coated with primary antibodies, specific - specific antibodies, lectins, enzymes, or streptavidin ; the linkage between magnetized beads coated materials are cleavable dna linker cell separation from the beads when the culturing of cells is more desirable. many of these beads have the same principles of separation ; however, the presence and different strength s of magnetic fields requires certain sizes of beads, based on the ramifications of the separation of the cell population. the larger sized beads ( > 2μm ) are the most commonly used range that was produced by dynal ( dynal [ uk ] ltd., wirral, merseyside, uk ; dynal, inc., lake success, ny ). where as smaller beads ( < 100 nm ) are mostly used for macs system that was produced by miltenyi biotech ( miltenyi biotech ltd., bisley, surrey
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##ynal, inc., lake success, ny ). where as smaller beads ( < 100 nm ) are mostly used for macs system that was produced by miltenyi biotech ( miltenyi biotech ltd., bisley, surrey, uk ; miltenyi biotech inc., auburn, ca ). immunomagnetic separation is used in a variety of scientific fields including molecular biology, microbiology, and immunology. ( 3 ) this technique of separation does not only consist of separation of cells within the blood, but can also be used for techniques of separation from primary tumors and in metastases research, through separation into component parts, creating a singular - cell delay, then allowing the suitable antibody to label the cell. in metastasis research this separation technique may become necessary to separate when given a cell population and wanting to isolate tumors cells in tumors, peripheral blood, and bone marrow. = = technique = = antibodies coating paramagnetic beads will bind to antigens present on the surface of cells thus capturing the cells and facilitate the concentration of these bead - attached cells. the concentration process is created by a magnet placed on the side of the test tube bringing the beads to it. macs systems ( magnetic cell separation system ) : through the usage of smaller super paramagnetic beads ( < 100 nm ), which requires a stronger magnetic field to separate cells. cells are labeled with primary antibodies and then macs beads are coated with specific - specific antibodies. these labeled cell suspension is then put into a separation column in a strong magnetic field. the labeled cells are contained, magnetized, while in the magnetic field and the unlabeled cells are suspended, un - magnetized, to be collected. once removed from magnetic field positive cells are eluted. these macs beads are then incorporated by the cells allowing them to remain in the column because they do not intrude with the cell attachment to the culture surface to cell - cell interactions. a bead removal reagent is then applied to have an enzymatically release of the macs beads allowing those cells to become relabeled with some other marker, which then is sorted. = = references = =
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worksoft, inc. is a software testing company founded in 1998 and headquartered in addison, texas. the company provides an automation platform for test automation, business process discovery, and documentation supporting enterprise applications, including packaged and web apps. in addition to its headquarters in addison, texas, the company has offices in london and munich. = = history = = worksoft was founded in 1998 by linda hayes, a co - founder of autotester, inc, and was initially funded by a contract with fidelity investments for y2k testing. worksoft certify was the first code - less automation tool designed for business analysts and is now a leader in the erp automation industry. texas - based austin ventures and california - based crecendo ventures were major investors. in 2010, worksoft acquired testfactory, a software testing company specializing in sap. in 2019, worksoft was acquired by marlin equity partners for an undisclosed sum. = = products = = worksoft certify is a test automation platform focused on business process testing. worksoft certify can be used to test erp applications, web apps, mobile apps, and more. the software is sap certified for integration with sap applications. other products include worksoft analyze, worksoft business reporting tool ( bpp ), worksoft execution suite, and process capture 2. 0. = = references = =
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the prize for innovation in distributed computing ( also called sirocco award ) is an award presented annually at the conference international colloquium on structural information and communication complexity ( sirocco ) to a living individual ( or individuals ) who have made a major contribution to understanding " the relationships between information and efficiency in decentralized computing ", which is main area of interest for this conference. the award recognizes innovation, in particular, it recognizes inventors of new ideas that were unorthodox and outside the mainstream at the time of their introduction. there are two restrictions for being eligible for this award : ( 1 ) the original contribution must have appeared in a publication at least five years before the year of the award, ( 2 ) one of the articles related to this contribution and authored by this candidate must have appeared in the proceedings of sirocco. the award was presented for the first time in 2009. = = winners = = = = see also = = list of computer science awards = = references = = = = external links = = official website
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hayandose is a cultural category used to express membership and belonging among zapotec migrants, described by cultural anthropologist lourdes gutierrez - najera. hayandose entails a process of creating ethnically - marked spaces among migrants in an effort to combat feelings of marginalization and displacement in a host country. this concept may be compared to the notion of native hubs developed by anthropologist renya ramirez to describe how urban native americans negotiate a transnational existence. = = beyond el barrio = = “ hayandose ”, in beyond el barrio : everyday life in latina / o america, examines the place of indigenous people within the broader scope of latino studies and also within the national political landscape. as argued in the text, indigenous subjects do not easily fit the category of " latino " used to describe national identities ; for example, guatemalan, mexican, ecuadorian. at the same time, indigenous migrants often are targets of racism and prejudice directed towards them. the essay is in conversation with other essays in the volume that interrogate the ways that latinos carve out niches for themselves and thrive in urban spaces within the united states. as the essay hayandose argues, such established spaces allow migrants, struggling with separation from their home country and racist stigmatization in their host country, to engage in a “ meaningful practice of belonging ” in which they are able to express their cultural membership. hayandose marks the point at which people finally feel as though they belong through the discovery of themselves in a foreign place. = = zapotecs / gutierrez - najera = = gutierrez - najera uses zapotecs as an example of migrants who originate from oaxaca, mexico and form their own spaces of belonging in the united states, specifically in los angeles. the zapotecs that gutierrez - najera writes about are from yalalag, a small rural town in the heart of oaxaca. the community of yalaltecos in los angeles comes together collectively and participates in festivals, ceremonies, tandas and other small gatherings where they can gossip in zapotec, share food, dance, financially and emotionally support one another, and engage in other customs and traditions from their place of origin. the existence and practice of customs and traditions that were once thought to be exclusive to yalalag, but that have now permeated american society, demonstrates the transnational character of yalaltecos indigeneity that makes possible the process of hayandose through the seizure and declaration of these ethnically -
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be exclusive to yalalag, but that have now permeated american society, demonstrates the transnational character of yalaltecos indigeneity that makes possible the process of hayandose through the seizure and declaration of these ethnically - marked spaces. yalaltecos living in los angeles have invoked their cultural identity hundreds of miles from home and have used it as a tool to resist the push for assimilation and marginalization within the united states. therefore, the transmission and continuity of culture across national borders are essential for yalaltecos to mark their own space and ultimately find themselves in a hostile environment far from their home country. with this new - found sense of belonging, the opportunity for “ rally [ ing ] for indigenous rights and the development of hometown communities in oaxaca, as well as to organize in the united states around immigrant legislation ” no longer remains out of reach. this claim is reaffirmed by another scholar, annice jacoby, who argues that the affirmation of transnational identities allows “ borders of ownership, space, and social agency ” to be challenged. once a migrant se hayan, or finds themselves, they have gained a sense of belonging by affirming their cultural membership and confronting their marginalization and displacement within a space collectively or individually marked as their own in the host country. this phenomenon then acts as a bridge for migrants to gain social ascendancy and acknowledgment that has the potential to improve lives in the home and host country alike. = = de / territorialization = = hayandose is also reflective of a contemporary cultural process known as de / territorialization. when emigrants moved to the united states they and their culture became deterritorialized. once they moved, however, they are simultaneously reterritorialized as they begin to form a space for themselves and practice their customs and traditions as they did in their home country. the theory of de / territorialization can be seen in the yalalteco community in los angeles through the perseverance of their cultural solidarity from oaxaca to california, and the maintenance of community ties that traverse national boundaries. the theories of de / territorialization and hayandose entail the movement of culture from one place to another, and thus reveal the “ multiple centers ” culture can obtain, as opposed to just a single " center " being the place of origin. because migration causes displacement among emigrants who are forced to adapt to a new environment, culture, and way of living, bringing the culture and customs that they practiced
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can obtain, as opposed to just a single " center " being the place of origin. because migration causes displacement among emigrants who are forced to adapt to a new environment, culture, and way of living, bringing the culture and customs that they practiced in their places of origin to their new location helps to combat these negative feelings and also adds an additional “ center ” to their particular culture. in regards to gutierrez - najera ’ s example, yalaltecos adopted los angeles as an additional “ center ” where their customs and traditions could be expressed as they would have been in yalalag. this sharing of cultures creates a cultural flow between the united states and oaxacan communities that have allowed emigrants not to lose their culture and sense of who they are, but to maintain it and ultimately use it as a powerful tool to engage in practices of belonging that resist sentiments of marginalization and displacement in new locations. = = references = =
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the heat death paradox, also known as thermodynamic paradox, clausius'paradox, and kelvin's paradox, is a reductio ad absurdum argument that uses thermodynamics to show the impossibility of an infinitely old universe. it was formulated in february 1862 by lord kelvin and expanded upon by hermann von helmholtz and william john macquorn rankine. = = the paradox = = assuming that the universe is eternal, a question arises : how is it that thermodynamic equilibrium has not already been achieved? this theoretical paradox is directed at the then - mainstream strand of belief in a classical view of a sempiternal universe, whereby its matter is postulated as everlasting and having always been recognisably the universe. heat death paradox is born of a paradigm resulting from fundamental ideas about the cosmos. it is necessary to change the paradigm to resolve the paradox. the paradox was based upon the rigid mechanical point of view of the second law of thermodynamics postulated by rudolf clausius and lord kelvin, according to which heat can only be transferred from a warmer to a colder object. it notes : if the universe were eternal, as claimed classically, it should already be cold and isotropic ( its objects should have the same temperature, and the distribution of matter or radiation should be even ). kelvin compared the universe to a clock that runs slower and slower, constantly dissipating energy in impalpable heat, although he was unsure whether it would stop for ever ( reach thermodynamic equilibrium ). according to this model, the existence of usable energy, which can be used to perform work and produce entropy, means that the clock has not stopped - since a conversion of heat in mechanical energy ( which kelvin called a rejuvenating universe scenario ) is not contemplated. according to the laws of thermodynamics, any hot object transfers heat to its cooler surroundings, until everything is at the same temperature. for two objects at the same temperature as much heat flows from one body as flows from the other, and the net effect is no change. if the universe were infinitely old, there must have been enough time for the stars to cool and warm their surroundings. everywhere should therefore be at the same temperature and there should either be no stars, or everything should be as hot as stars. the universe should thus achieve, or asymptotically tend to, thermodynamic equilibrium, which corresponds to a
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should therefore be at the same temperature and there should either be no stars, or everything should be as hot as stars. the universe should thus achieve, or asymptotically tend to, thermodynamic equilibrium, which corresponds to a state where no thermodynamic free energy is left, and therefore no further work is possible : this is the heat death of the universe, as predicted by lord kelvin in 1852. the average temperature of the cosmos should also asymptotically tend to kelvin zero, and it is possible that a maximum entropy state will be reached. = = kelvin's solution = = in february 1862, lord kelvin used the existence of the sun and the stars as an empirical proof that the universe has not achieved thermodynamic equilibrium, as entropy production and free work are still possible, and there are temperature differences between objects. helmholtz and rankine expanded kelvin's work soon after. since there are stars and colder objects, the universe is not in thermodynamic equilibrium, so it cannot be infinitely old. = = = modern cosmology = = = the paradox does not arise in the big bang or its successful lambda - cdm refinement, which posit that the universe began roughly 13. 8 billion years ago, not long enough ago for the universe to have approached thermodynamic equilibrium. some proposed further refinements, termed eternal inflation, restore kelvin's idea of unending time in the more complicated form of an eternal, exponentially - expanding multiverse in which mutually - inaccessible baby universes, some of which resemble the universe we inhabit, are continually being born. = = related paradoxes = = olbers'paradox is another paradox which aims to disprove an infinitely old static universe, but it only fits with a static universe scenario. also, unlike kelvin's paradox, it relies on cosmology rather than thermodynamics. the boltzmann brain can also be related to kelvin's, as it focuses on the spontaneous generation of a brain ( filled with false memories ) from entropy fluctuations, in a universe which has been lying in a heat death state for an indefinite amount of time. = = see also = = entropy as an arrow of time heat death of the universe list of paradoxes thermodynamic temperature = = references = =
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circadian rhythm sleep disorders ( crsd ), also known as circadian rhythm sleep – wake disorders ( crswd ), are a family of sleep disorders that affect the timing of sleep. crsds cause a persistent pattern of sleep / wake disturbances that arise either by dysfunction in one's biological clock system, or by misalignment between one's endogenous oscillator and externally imposed cues. as a result of this misalignment, those affected by circadian rhythm sleep disorders can fall asleep at unconventional time points in the day, or experience excessive daytime sleepiness if they resist. these occurrences often lead to recurring instances of disrupted rest and wakefulness, where individuals affected by the disorder are unable to go to sleep and awaken at " normal " times for work, school, and other social obligations. delayed sleep phase disorder, advanced sleep phase disorder, non - 24 - hour sleep – wake disorder and irregular sleep – wake rhythm disorder represent the four main types of crsd. = = overview = = humans, like most living organisms, have various biological rhythms. these biological clocks control processes that fluctuate daily ( e. g., body temperature, alertness, hormone secretion ), generating circadian rhythms. among these physiological characteristics, the sleep – wake propensity can also be considered one of the daily rhythms regulated by the biological clock system. humans'sleeping cycles are tightly regulated by a series of circadian processes working in tandem, allowing for the experience of moments of consolidated sleep during the night and a long wakeful moment during the day. iprgcs ( intrinsically photosensitive retinal ganglion cells ), for example, are involved in modulating the circadian rhythm because of the expression of melanopsin, which absorbs light in the blue part ( around 480 nm ). conversely, disruptions to these processes and the communication pathways between them can lead to problems in sleeping patterns, which are collectively referred to as circadian rhythm sleep disorders. = = normal rhythm = = a circadian rhythm is an entrainable, endogenous, biological activity that has a period of roughly twenty - four hours. this internal time - keeping mechanism is centralized in the suprachiasmatic nucleus ( scn ) of humans, and allows for the internal physiological mechanisms underlying sleep and alertness to become synchronized to external environmental cues, like the light - dark cycle. the scn also sends signals to peripheral clocks in other organs, like the liver, to control processes such
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humans, and allows for the internal physiological mechanisms underlying sleep and alertness to become synchronized to external environmental cues, like the light - dark cycle. the scn also sends signals to peripheral clocks in other organs, like the liver, to control processes such as glucose metabolism. although these rhythms will persist in constant light or dark conditions, different zeitgebers ( time givers such as the light - dark cycle ) give context to the clock and allow it to entrain and regulate expression of physiological processes to adjust to the changing environment. genes that help control light - induced entrainment include positive regulators bmal1 and clock and negative regulators per1 and cry. a full circadian cycle can be described as a twenty - four hour circadian day, where circadian time zero ( ct 0 ) marks the beginning of a subjective day for an organism and ct 12 marks the start of subjective night. humans with regular circadian function have been shown to maintain regular sleep schedules, regulate daily rhythms in hormone secretion, and sustain oscillations in core body temperature. even in the absence of zeitgebers, humans will continue to maintain a roughly 24 - hour rhythm in these biological activities. regarding sleep, normal circadian function allows people to maintain balance rest and wakefulness that allows people to work and maintain alertness during the day's activities, and rest at night. some misconceptions regarding circadian rhythms and sleep commonly mislabel irregular sleep as a circadian rhythm sleep disorder ( crsd ). in order to be diagnosed with crsd, there must be either a misalignment between the timing of the circadian oscillator and the surrounding environment, or failure in the clock entrainment pathway. among people with typical circadian clock function, there is variation in chronotypes, or preferred wake and sleep times, of individuals. although chronotype varies from individual to individual, as determined by rhythmic expression of clock genes, people with typical circadian clock function will be able to entrain to environmental cues. for example, if a person wishes to shift the onset of a biological activity, like waking time, light exposure during the late subjective night or early subjective morning can help advance one's circadian cycle earlier in the day, leading to an earlier wake time. = = diagnosis = = the international classification of sleep disorders classifies circadian rhythm sleep disorder as a type of sleep dyssomnia. although studies suggest that 3 % of the adult population has a crsd, many people are
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earlier wake time. = = diagnosis = = the international classification of sleep disorders classifies circadian rhythm sleep disorder as a type of sleep dyssomnia. although studies suggest that 3 % of the adult population has a crsd, many people are often misdiagnosed with insomnia instead of a crsd. of adults diagnosed with sleep disorders, an estimated 10 % have a crsd and of adolescents with sleep disorders, an estimated 16 % may have a crsd. patients diagnosed with circadian rhythm sleep disorders typically express a pattern of disturbed sleep, whether that be excessive sleep that intrudes on working schedules and daily functions, or insomnia at desired times of sleep. note that having a preference for extreme early or late wake times is not related to a circadian rhythm sleep disorder diagnosis. there must be distinct impairment of biological rhythms that affects the person's desired work and daily behavior. for a crsd diagnosis, a sleep specialist gathers the history of a patient's sleep and wake habits, body temperature patterns, and dim - light melatonin onset ( dlmo ). gathering this data gives insight into the patient's current schedule, as well as the physiological phase markers of the patient's biological clock. the start of the crsd diagnostic process is a thorough sleep history assessment. a standard questionnaire is used to record the sleep habits of the patient, including typical bedtime, sleep duration, sleep latency, and instances of waking up. the professional will further inquire about other external factors that may impact sleep. prescription drugs that treat mood disorders like tricyclic antidepressants, selective serotonin reuptake inhibitors and other antidepressants are associated with abnormal sleep behaviors. other daily habits like work schedule and timing of exercise are also recorded — because they may impact an individual's sleep and wake patterns. to measure sleep variables candidly, patients wear actigraphy watches that record sleep onset, wake time, and many other physiological variables. patients are similarly asked to self - report their sleep habits with a week - long sleep diary to document when they go to bed, when they wake up, etc. to supplement the actigraphy data. collecting this data allows sleep professionals to carefully document and measure patient's sleep habits and confirm patterns described in their sleep history. other additional ways to classify the nature of a patient's sleep and biological clock are the morningness - eveningness questionnaire ( meq ) and the munich chronotype questionnaire, both of which have fairly
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patterns described in their sleep history. other additional ways to classify the nature of a patient's sleep and biological clock are the morningness - eveningness questionnaire ( meq ) and the munich chronotype questionnaire, both of which have fairly strong correlations with accurately reporting phase advanced or delayed sleep. questionnaires like the pittsburgh sleep quality index ( psqi ) and the insomnia severity index ( isi ) help gauge the severity of sleep disruption. specifically, these questionnaires can help the professional assess the patient's problems with sleep latency, undesired early - morning wakefulness, and problems with falling or staying asleep. tayside children's sleep questionnaire is a ten - item questionnaire for sleep disorders in children aged between one and five years old. = = types = = currently, the international classification of sleep disorders ( icsd - 3 ) lists 6 disorders under the category of circadian rhythm sleep disorders. crsds can be categorized into two groups based on their underlying mechanisms : the first category is composed of disorders where the endogenous oscillator has been altered, known as intrinsic type disorders. the second category consists of disorders in which the external environment and the endogenous circadian clock are misaligned, called extrinsic type crsds. = = = intrinsic = = = delayed sleep phase disorder ( dspd ) : individuals who have been diagnosed with delayed sleep phase disorder have sleep – wake times that are delayed when compared to normal functioning individuals. people with dspd typically have very long periods of sleep latency when they attempt to go to sleep during conventional sleeping times. similarly, they also have trouble waking up at conventional times. advanced sleep phase disorder ( aspd ) : people with advanced sleep phase disorder exhibit characteristics opposite to those with delayed sleep phase disorder. these individuals have advanced sleep – wake times, so they tend to go to bed and wake up much earlier as compared to normal individuals. aspd is less common than dspd, and is most prevalent within older populations. familial advanced sleep phase syndrome ( fasps ) is linked to an autosomal dominant mode of inheritance. it is associated with a missense mutation in human per2 that replaces serine for glycine at position 662 ( s662g ). irregular sleep – wake rhythm disorder ( iswrd ) is characterized by a normal 24 h sleeping period. however, individuals with this disorder experience fragmented and highly disorganized sleep that can manifest in the
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662 ( s662g ). irregular sleep – wake rhythm disorder ( iswrd ) is characterized by a normal 24 h sleeping period. however, individuals with this disorder experience fragmented and highly disorganized sleep that can manifest in the form of waking frequently during the night and taking naps during the day, yet still maintaining sufficient total time asleep. people with iswrd often experience a range of symptoms from insomnia to excessive daytime sleepiness. non - 24 - hour sleep – wake disorder ( n24swd ) : most common in individuals that are blind and unable to detect light, is characterized by chronic patterns of sleep / wake cycles that are not entrained to the 24 h light – dark environmental cycle. as a result of this, individuals with this disorder will usually experience a gradual yet predictable delay of sleep onset and waking times. patients with dspd may develop this disorder if their condition is untreated. = = = extrinsic = = = shift work sleep disorder ( swsd ) : approximately 9 % of americans who work night or irregular work shifts are believed to experience shift work sleep disorder. night shift work directly opposes the environmental cues that entrain our biological clock, so this disorder arises when an individual's clock is unable to adjust to the socially imposed work schedule. shift work sleep disorder can lead to severe cases of insomnia as well as excessive daytime sleepiness. jet lag : jet lag is best characterized by difficulty falling asleep or staying asleep as a result of misalignment between one's internal circadian system and external, or environmental cues. it is typically associated with rapid travel across multiple time zones. = = alzheimer's disease = = crsd has been frequently associated with excessive daytime sleepiness and nighttime insomnia in patients diagnosed with alzheimer's disease ( ad ), representing a common characteristic among ad patients as well as a risk factor of progressive functional impairments. on one hand, it has been stated that people with ad have melatonin alteration and high irregularity in their circadian rhythm that lead to a disrupted sleep – wake cycle, probably due to damage on hypothalamic scn regions typically observed in ad. on the other hand, disturbed sleep and wakefulness states have been related to worsening of an ad patient's cognitive abilities, emotional state and quality of life. moreover, the abnormal behavioural symptoms of the disease negatively contribute to overwhelming patients'relatives and caregivers as well. however, the impact of sleep –
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to worsening of an ad patient's cognitive abilities, emotional state and quality of life. moreover, the abnormal behavioural symptoms of the disease negatively contribute to overwhelming patients'relatives and caregivers as well. however, the impact of sleep – wake disturbances on the subjective experience of a person with ad is not yet fully understood. therefore, further studies exploring this field have been highly recommended, mainly considering the increasing life expectancy and significance of neurodegenerative diseases in clinical practices. = = treatment = = possible treatments for circadian rhythm sleep disorders include : chronotherapy has been shown to effectively treat delayed sleep phase disorder ; it acts by systematically delaying an individual's bedtime until their sleep – wake times coincide with the conventional 24 h day. light therapy utilizes bright light exposure to induce phase advances and delays in sleep and wake times. this therapy requires 30 – 60 minutes of exposure to a bright ( 5000 – 10000 lux ) white, blue, or natural light at a set time until the circadian clock is aligned with the desired schedule. treatment is initially administered either upon awakening or before sleeping, and if successful may be continued indefinitely or performed less frequently. though proven very effective in the treatment of individuals with dspd and aspd, the benefits of light therapy on n24swd, shift work disorder, and jet lag have not been studied as extensively. hypnotics have also been used clinically alongside bright light exposure therapy and pharmacotherapy for the treatment of crsds such as advanced sleep phase disorder. additionally, in conjunction with cognitive behavioral therapy, short - acting hypnotics also present an avenue for treating co - morbid insomnia in patients with circadian sleep disorders. melatonin, a naturally occurring biological hormone with circadian rhythmicity, has been shown to promote sleep and entrainment to external cues when administered in drug form ( 0. 5 – 5. 0 mg ). melatonin administered in the evening causes phase advances in sleep – wake times while maintaining duration and quality of sleep. similarly, when administered in the early morning, melatonin can cause phase delays. it has been shown most effective in cases of shift work sleep disorder and delayed phase sleep disorder, but has not been proven particularly useful in cases of jet lag. dark therapy, for example, the use of blue - blocking goggles, is used to block blue and blue - green wavelength light from reaching the eye during evening hours so as not to hinder melatonin production. = = see also
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##g. dark therapy, for example, the use of blue - blocking goggles, is used to block blue and blue - green wavelength light from reaching the eye during evening hours so as not to hinder melatonin production. = = see also = = = = references = = = = external links = = circadian sleep disorders network an american academy of sleep medicine review : circadian rhythm sleep disorders : part i, basic principles, shift work and jet lag disorders. pdf, 24 pages. november 2007. archived 8 august 2017 at the wayback machine an american academy of sleep medicine review : circadian rhythm sleep disorders : part ii, advanced sleep phase disorder, delayed sleep phase disorder, free - running disorder, and irregular sleep – wake rhythm. pdf, 18 pages. november 2007. an american academy of sleep medicine report : practice parameters for the clinical evaluation and treatment of circadian rhythm sleep disorders, november 1, 2007 nasa sleep – wake actigraphy and light exposure during spaceflight - long experiment
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in the field of computational neuroscience, the theory of metastability refers to the human brain's ability to integrate several functional parts and to produce neural oscillations in a cooperative and coordinated manner, providing the basis for conscious activity. metastability, a state in which signals ( such as oscillatory waves ) fall outside their natural equilibrium state but persist for an extended period of time, is a principle that describes the brain's ability to make sense out of seemingly random environmental cues. in the past 25 years, interest in metastability and the underlying framework of nonlinear dynamics has been fueled by advancements in the methods by which computers model brain activity. = = overview = = eeg measures the gross electrical activity of the brain that can be observed on the surface of the skull. in the metastability theory, eeg outputs produce oscillations that can be described as having identifiable patterns that correlate with each other at certain frequencies. each neuron in a neuronal network normally outputs a dynamical oscillatory waveform, but also has the ability to output a chaotic waveform. when neurons are integrated into the neural network by interfacing neurons with each other, the dynamical oscillations created by each neuron can be combined to form highly predictable eeg oscillations. by identifying these correlations and the individual neurons that contribute to predictable eeg oscillations, scientists can determine which cortical domains are processing in parallel and which neuronal networks are intertwined. in many cases, metastability describes instances in which distal parts of the brain interact with each other to respond to environmental stimuli. = = frequency domains of metastability = = it has been suggested that one integral facet of brain dynamics underlying conscious thought is the brain's ability to convert seemingly noisy or chaotic signals into predictable oscillatory patterns. in eeg oscillations of neural networks, neighboring waveform frequencies are correlated on a logarithmic scale rather than a linear scale. as a result, mean frequencies in oscillatory bands cannot link together according to linearity of their mean frequencies. instead, phase transitions are linked according to their ability to couple with adjacent phase shifts in a constant state of transition between unstable and stable phase synchronization. this phase synchronization forms the basis of metastable behavior in neural networks. metastable behavior occurs at the high frequency domain known as 1 / f regime. this regime describes an environment
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between unstable and stable phase synchronization. this phase synchronization forms the basis of metastable behavior in neural networks. metastable behavior occurs at the high frequency domain known as 1 / f regime. this regime describes an environment in which a noisy signal ( also known as pink noise ) has been induced, where the amount of power the signal outputs over a certain bandwidth ( its power spectral density ) is inversely proportional to its frequency. noise at the 1 / f regime can be found in many biological systems – for instance, in the output of a heartbeat in an ecg waveform — but serves a unique purpose for phase synchrony in neuronal networks. at the 1 / f regime, the brain is in the critical state necessary for a conscious response to weak or chaotic environmental signals because it can shift the random signals into identifiable and predictable oscillatory waveforms. while often transient, these waveforms exist in a stable form long enough to contribute to what can be thought of as conscious response to environmental stimuli. = = theories of metastability = = = = = oscillatory activity and coordination dynamics = = = the dynamical system model, which represents networks composed of integrated neural systems communicating with one another between unstable and stable phases, has become an increasingly popular theory underpinning the understanding of metastability. coordination dynamics forms the basis for this dynamical system model by describing mathematical formulae and paradigms governing the coupling of environmental stimuli to their effectors. = = = = history of coordination dynamics and the haken - kelso - bunz ( hkb ) model = = = = the so - named hkb model is one of the earliest and well - respected theories to describe coordination dynamics in the brain. in this model, the formation of neural networks can be partly described as self - organization, where individual neurons and small neuronal systems aggregate and coordinate to either adapt or respond to local stimuli or to divide labor and specialize in function. in the last 20 years, the hkb model has become a widely accepted theory to explain the coordinated movements and behaviors of individual neurons into large, end - to - end neural networks. originally the model described a system in which spontaneous transitions observed in finger movements could be described as a series of in - phase and out - of - phase movements. in the mid - 1980s hkb model experiments, subjects were asked to wave one finger on each hand in two modes of direction : first, known as out of phase, both fingers moving in
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of in - phase and out - of - phase movements. in the mid - 1980s hkb model experiments, subjects were asked to wave one finger on each hand in two modes of direction : first, known as out of phase, both fingers moving in the same direction back and forth ( as windshield wipers might move ) ; and second, known as in - phase, where both fingers come together and move away to and from the midline of the body. to illustrate coordination dynamics, the subjects were asked to move their fingers out of phase with increasing speed until their fingers were moving as fast as possible. as movement approached its critical speed, the subjects ’ fingers were found to move from out - of - phase ( windshield - wiper - like ) movement to in - phase ( toward midline movement ). the hkb model, which has also been elucidated by several complex mathematical descriptors, is still a relatively simple but powerful way to describe seemingly - independent systems that come to reach synchrony just before a state of self - organized criticality. = = = = evolution of cognitive coordination dynamics = = = = in the last 10 years, the hkb model has been reconciled with advanced mathematical models and supercomputer - based computation to link rudimentary coordination dynamics to higher - order processes such as learning and memory. the traditional eeg is still useful to investigate coordination between different parts of the brain. 40 hz gamma wave activity is a prominent example of the brain's ability to be modeled dynamically and is a common example of coordination dynamics. continuous study of these and other oscillations has led to an important conclusion : analyzing waves as having a common signal phase but a different amplitude leads to the possibility that these different signals serve a synergistic function. some unusual characteristics of these waves : they are virtually simultaneous and have a very short onset latency, which implies that they operate faster than synaptic conduction would allow ; and that their recognizable patterns are sometimes interrupted by periods of randomness. the latter idiosyncrasy has served as the basis for assuming an interaction and transition between neural subsystems. analysis of activation and deactivation of regions of the cortex has shown a dynamic shift between dependence and interdependence, reflecting the brain's metastable nature as a function of a coordinated dynamical system. fmri, large - scale electrode arrays, and meg expand upon the patterns seen in eeg by providing visual confirmation of coordinated dynamics. the meg, which provides
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the brain's metastable nature as a function of a coordinated dynamical system. fmri, large - scale electrode arrays, and meg expand upon the patterns seen in eeg by providing visual confirmation of coordinated dynamics. the meg, which provides an improvement over eeg in spatiotemporal characterization, allows researchers to stimulate certain parts of the brain with environmental cues and observe the response in a holistic brain model. additionally, meg has a response time of about one millisecond, allowing for a virtually real - time investigation of the active turning - on and - off of selected parts of the brain in response to environmental cues and conscious tasks. = = = = social coordination dynamics and the phi complex = = = = a developing field in coordination dynamics involves the theory of social coordination, which attempts to relate the dc to normal human development of complex social cues following certain patterns of interaction. this work is aimed at understanding how human social interaction is mediated by metastability of neural networks. fmri and eeg are particularly useful in mapping thalamocortical response to social cues in experimental studies. a new theory called the phi complex has been developed by j. a. scott kelso and fellow researchers at florida atlantic university to provide experimental results for the theory of social coordination dynamics. in kelso's experiments, two subjects were separated by an opaque barrier and asked to wag their fingers ; then the barrier was removed and the subjects were instructed to continue to wag their fingers as if no change had occurred. after a short period, the movements of the two subjects sometimes became coordinated and synchronized ( but other times continued to be asynchronous ). the link between eeg and conscious social interaction is described as phi, one of several brain rhythms operating in the 10 hz range. phi consists of two components : one to favor solitary behavior and another to favor interactive ( interpersonal ) behavior. further analysis of phi may reveal the social and interpersonal implications of degenerative diseases such as schizophrenia — or may provide insight into common social relationships such as the dynamics of alpha and omega - males or the popular bystander effect describing how people diffuse personal responsibility in emergency situations depending on the number of other individuals present. = = = dynamic core = = = a second theory of metastability involves a so - called dynamic core, which is a term to loosely describe the thalamocortical region believed to be the integration center of consciousness. the dynamic core hypothesis ( dch ) reflects the use and disus
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theory of metastability involves a so - called dynamic core, which is a term to loosely describe the thalamocortical region believed to be the integration center of consciousness. the dynamic core hypothesis ( dch ) reflects the use and disuse of interconnected neuronal networks during stimulation of this region. a computer model of 65, 000 spiking neurons shows that neuronal groups existing in the cortex and thalamus interact in the form of synchronous oscillation. the interaction between distinct neuronal groups forms the dynamic core and may help explain the nature of conscious experience. a critical feature of the dch is that instead of thinking binarily about transitions between neural integration and non - integration ( i. e., that the two are either one or the other with no in - between ), the metastable nature of the dynamic core can allow for a continuum of integration. = = = = neural darwinism = = = = one theory used to integrate the dynamic core with conscious thought involves a developing concept known as neural darwinism. in this model, metastable interactions in the thalamocortical region cause a process of selectionism via re - entry ( a phenomenon describing the overall reciprocity and interactivity between signals in distant parts of the brain through coupled signal latency ). neuronal selectivity involves mechanochemical events that take place pre - and post - natally whereby neuronal connections are influenced by environmental experiences. the modification of synaptic signals as it relates to the dynamic core provides further explanation for the dch. despite growing evidence for the dch, the ability to generate mathematical constructs to model and predict dynamic core behavior has been slow to progress. continued development of stochastic processes designed to graph neuronal signals as chaotic and non - linear has provided some algorithmic basis for analyzing how chaotic environmental signals are coupled to enhance selectivity of neural outgrowth or coordination in the dynamic core. = = = global workspace hypothesis = = = the global workspace hypothesis is another theory to elucidate metastability, and has existed in some form since 1983. this hypothesis also focuses on the phenomenon of re - entry, the ability of a routine or process to be used by multiple parts of the brain simultaneously. both the dch and global neuronal workspace ( gnw ) models involve re - entrance, but the gnw model elaborates on re - entrant connectivity between distant parts of the
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by multiple parts of the brain simultaneously. both the dch and global neuronal workspace ( gnw ) models involve re - entrance, but the gnw model elaborates on re - entrant connectivity between distant parts of the brain and long - range signal flow. workspace neurons are similar anatomically but separated spatially from each other. one interesting aspect of the gnw is that with sufficient intensity and length over which a signal travels, a small initiation signal can be compounded to activate an " ignition " of a critical spike - inducing state. this idea is analogous to a skier on the slope of a mountain, who, by disrupting a few blocks of ice with his skis, initiates a giant avalanche in his wake. to help prove the circuit - like amplification theory, research has shown that inducing lesions in long - distance connections corrupts performance in integrative models. a popular experiment to demonstrate the global workspace hypothesis involves showing a subject a series of backward - masked visual words ( e. g., " the dog sleeps quietly " is shown as " ylteiuq speels god eht " ) and then asking the subject to identify the forward " translation " of these words. not only did fmri detect activity in the word - recognition portion of the cortex, but additionally, activity is often detected in the parietal and prefrontal cortices. in almost every experiment, conscious input in word and audition tasks shows a much wider use of integrated portions of the brain than in identical unconscious input. the wide distribution and constant signal transfer between different areas of the brain in experimental results is a common method to attempt to prove the neural workspace hypothesis. more studies are being conducted to determine precisely the correlation between conscious and unconscious task deliberation in the realm of the global workspace. = = = the operational architectonics theory of brain – mind = = = although the concept of metastability has been around in neuroscience for some time, the specific interpretation of metastability in the context of brain operations of different complexity has been developed by andrew and alexander fingelkurts within their model of operational architectonics of brain – mind functioning. metastability is basically a theory of how global integrative and local segregative tendencies coexist in the brain. the operational architectonics is centered on the fact that in the metastable regime of brain functioning, the individual parts of the brain exhibit tendencies to function autonomously at the same time
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and local segregative tendencies coexist in the brain. the operational architectonics is centered on the fact that in the metastable regime of brain functioning, the individual parts of the brain exhibit tendencies to function autonomously at the same time as they exhibit tendencies for coordinated activity. in accordance with operational architectonics, the synchronized operations produced by distributed neuronal assemblies constitute the metastable spatial - temporal patterns. they are metastable because intrinsic differences in the activity between neuronal assemblies are sufficiently large that they each do their own job ( operation ), while still retaining a tendency to be coordinated together in order to realize the complex brain operation. = = the future of metastability = = in addition to study investigating the effects of metastable interactions on traditional social function, much research will likely focus on determining the role of the coordinated dynamic system and the global workspace in the progression of debilitating diseases such as alzheimer's disease, parkinson's disease, stroke, and schizophrenia. an interest in the effect of a traumatic or semi - traumatic brain injury ( tbi ) on the coordinated dynamical system has developed in the last five years as the number of tbi cases has risen from war - related injuries. = = see also = = cognitive psychology electroencephalogram = = references = =
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the term center or centre is used in various contexts in abstract algebra to denote the set of all those elements that commute with all other elements. the center of a group g consists of all those elements x in g such that xg = gx for all g in g. this is a normal subgroup of g. the similarly named notion for a semigroup is defined likewise and it is a subsemigroup. the center of a ring ( or an associative algebra ) r is the subset of r consisting of all those elements x of r such that xr = rx for all r in r. the center is a commutative subring of r. the center of a lie algebra l consists of all those elements x in l such that [ x, a ] = 0 for all a in l. this is an ideal of the lie algebra l. = = see also = = centralizer and normalizer center ( category theory ) = = references = =
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the effects of the covid - 19 pandemic, a global pandemic of coronavirus disease 2019 ( covid - 19 ) caused by severe acute respiratory syndrome coronavirus 2 ( sars cov ‑ 2 ), have been broad, affecting general society, the global economy, culture, ecology, politics, and other areas. these aspects are discussed across many articles : = = economic impact = = 2020 russia – saudi arabia oil price war 2020 stock market crash charitable activities related to the covid - 19 pandemic moldovan – romanian collaboration during the covid - 19 pandemic covid - 19 recession financial market impact of the covid - 19 pandemic impact of the covid - 19 pandemic on mink farming = = = by country = = = economic impact of the covid - 19 pandemic in canada economic impact of the covid - 19 pandemic in india indian migrant workers during the covid - 19 pandemic economic impact of the covid - 19 pandemic in the republic of ireland covid - 19 pandemic unemployment payment july jobs stimulus economic recovery plan 2021 economic impact of the covid - 19 pandemic in malaysia economic impact of the covid - 19 pandemic in new zealand economic impact of the covid - 19 pandemic in russia economic impact of the covid - 19 pandemic in the united kingdom economic impact of the covid - 19 pandemic in the united states = = = by industry = = = impact of the covid - 19 pandemic on aviation impact of the covid - 19 pandemic on airlines world's longest domestic flight impact of the covid - 19 pandemic on the cannabis industry impact of the covid - 19 pandemic on consumer products impact of the covid - 19 pandemic on the food industry impact of the covid - 19 pandemic on the meat industry in canada impact of the covid - 19 pandemic on the meat industry in the united states impact of the covid - 19 pandemic on the restaurant industry impact of the covid - 19 pandemic on the restaurant industry in the united states impact of the covid - 19 pandemic on journalism impact of the covid - 19 pandemic on retail impact of the covid - 19 pandemic on tourism travel restrictions related to the covid - 19 pandemic = = impact on culture and entertainment = = impact of the covid - 19 pandemic
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- 19 pandemic on retail impact of the covid - 19 pandemic on tourism travel restrictions related to the covid - 19 pandemic = = impact on culture and entertainment = = impact of the covid - 19 pandemic on cinema list of films impacted by the covid - 19 pandemic impact of the covid - 19 pandemic on education 2020 uk gcse and a - level grading controversy homeschooling during the covid - 19 pandemic impact of the covid - 19 pandemic on education in ghana impact of the covid - 19 pandemic on education in the republic of ireland impact of the covid - 19 pandemic on education in the united kingdom impact of the covid - 19 pandemic on education in the united states impact of the covid - 19 pandemic on sports by type impact of the covid - 19 pandemic on association football impact of the covid - 19 pandemic on combat sports impact of the covid - 19 pandemic on cricket impact of the covid - 19 pandemic on disc golf impact of the covid - 19 pandemic on gaelic games impact of the covid - 19 pandemic on motorsport impact of the covid - 19 pandemic on rugby league by country impact of the covid - 19 pandemic on sports in the republic of ireland impact of the covid - 19 pandemic on philippine sports suspension of the 2019 – 20 nba season impact of the covid - 19 pandemic on television impact of the covid - 19 pandemic on television in the united states list of american television series impacted by the covid - 19 pandemic impact of the covid - 19 pandemic on the arts and cultural heritage covid - 19 pandemic in popular culture impact of the covid - 19 pandemic on the fashion industry impact of the covid - 19 pandemic on the music industry impact of the covid - 19 pandemic on the performing arts impact of the covid - 19 pandemic on the video game industry impact of the covid - 19 pandemic on the walt disney company = = impact on information = = media coverage of the covid - 19 pandemic misinformation related to the covid - 19 pandemic covid - 19 misinformation by governments covid - 19 misinformation by china covid - 19 misinformation by the united states
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19 pandemic misinformation related to the covid - 19 pandemic covid - 19 misinformation by governments covid - 19 misinformation by china covid - 19 misinformation by the united states covid - 19 misinformation in canada covid - 19 misinformation in the philippines list of unproven methods against covid - 19 plandemic wikipedia's response to the covid - 19 pandemic = = impact on society and rights = = gendered impact of the covid - 19 pandemic human rights issues related to the covid - 19 pandemic covid - 19 pandemic on human rights in argentina impact of the covid - 19 pandemic on children impact of the covid - 19 pandemic on foster care in the united states impact of the covid - 19 pandemic on healthcare workers legal issues impact of the covid - 19 pandemic on abortion in the united states impact of the covid - 19 pandemic on crime impact of the covid - 19 pandemic on domestic violence impact of the covid - 19 pandemic on prisons impact of the covid - 19 pandemic on long - term care facilities impact of the covid - 19 pandemic on the lgbt community impact of the covid - 19 pandemic on public transport impact of the covid - 19 pandemic on religion impact of the covid - 19 pandemic on funerals impact of the covid - 19 pandemic on hajj impact of the covid - 19 pandemic on the catholic church xenophobia and racism related to the covid - 19 pandemic mental health during the covid - 19 pandemic social impact of the covid - 19 pandemic coronavirus party impact of the covid - 19 pandemic on social media social impact of the covid - 19 pandemic in malaysia social impact of the covid - 19 pandemic in new zealand social impact of the covid - 19 pandemic in russia social impact of the covid - 19 pandemic in the republic of ireland social impact of the covid - 19 pandemic in the united kingdom social impact of the covid - 19 pandemic in the united states impact of the covid - 19 pandemic on african - american communities impact of the covid - 19 pandemic on native american tribes and tribal communities social stigma associated with
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impact of the covid - 19 pandemic in the united states impact of the covid - 19 pandemic on african - american communities impact of the covid - 19 pandemic on native american tribes and tribal communities social stigma associated with covid - 19 strikes during the covid - 19 pandemic workplace hazard controls for covid - 19 = = political impact = = by country : impact of the covid - 19 pandemic on politics in malaysia impact of the covid - 19 pandemic on politics in the republic of ireland impact of the covid - 19 pandemic on politics in russia european union response to the covid - 19 pandemic impact of the covid - 19 pandemic on international relations federal aid during the covid - 19 pandemic in canada international aid related to the covid - 19 pandemic international reactions to the covid - 19 pandemic in italy global ceasefire list of covid - 19 pandemic legislation national responses to the covid - 19 pandemic british government response to the covid - 19 pandemic german government response to the covid - 19 pandemic ghanaian government response to the covid - 19 pandemic indian government response to the covid - 19 pandemic indian state government responses to the covid - 19 pandemic irish government response to the covid - 19 pandemic new zealand government response to the covid - 19 pandemic nigerian government response to the covid - 19 pandemic philippine government response to the covid - 19 pandemic russian government responses to the covid - 19 pandemic swedish government response to the covid - 19 pandemic united states responses to the covid - 19 pandemic u. s. federal government response to the covid - 19 pandemic trump administration communication during the covid - 19 pandemic u. s. state and local government responses to the covid - 19 pandemic california government response to the covid - 19 pandemic eastern states multi - state council midwest governors regional pact new york state government response to the covid - 19 pandemic texas government response to the covid - 19 pandemic western states pact vietnamese government response to the covid - 19 pandemic protests over responses to the covid - 19 pandemic protests over covid - 19 policies in italy protests over covid - 19 policies in germany covid - 19 anti - lockdown protests in new zealand 2020 – 2021
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- 19 pandemic protests over responses to the covid - 19 pandemic protests over covid - 19 policies in italy protests over covid - 19 policies in germany covid - 19 anti - lockdown protests in new zealand 2020 – 2021 serbian protests covid - 19 anti - lockdown protests in the united kingdom covid - 19 anti - lockdown protests in the united states 2020 united states anti - lockdown protests open the states united nations'response to the covid - 19 pandemic world health organization's response to the covid - 19 pandemic = = others = = anthropause covid - 19 lockdowns evacuations related to the covid - 19 pandemic evacuations by india related to the covid - 19 pandemic evacuations by the philippines related to the covid - 19 pandemic food security during the covid - 19 pandemic impact of the covid - 19 pandemic on animals impact of the covid - 19 pandemic on hospitals impact of the covid - 19 pandemic on icu capacity impact of the covid - 19 pandemic on language impact of the covid - 19 pandemic on other health issues impact of the covid - 19 pandemic on overseas filipinos impact of the covid - 19 pandemic on people with disabilities impact of the covid - 19 pandemic on science and technology impact of the covid - 19 pandemic on the environment impact of the covid - 19 pandemic on migration impact of the covid - 19 pandemic on the military withdrawal of u. s. troops from iraq pandemic fatigue shortages related to the covid - 19 pandemic covid - 19 pandemic deaths list of deaths due to covid - 19 covid - 19 pandemic death rates by country
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eating your own dog food or " dogfooding " is the practice of using one's own products or services. this can be a way for an organization to test its products in real - world usage using product management techniques. hence dogfooding can act as quality control, and eventually a kind of testimonial advertising. once in the market, dogfooding can demonstrate developers'confidence in their own products. = = origin of the term = = in 2006, warren harrison, the editor - in - chief of ieee software recounted that in the 1970s television advertisements for alpo dog food, spokesperson and actor lorne greene pointed out that he fed alpo to his own dogs. another possible origin he remembered was that the president of kal kan pet food was said to eat a can of his dog food at annual shareholders'meetings. in 1988, microsoft manager paul maritz sent brian valentine, test manager for microsoft lan manager, an email titled " eating our own dogfood ", challenging him to increase internal usage of the company's product. from there, the usage of the term spread through the company. = = real world usage = = infoworld commented that this needs to be a transparent and honest process : watered - down examples, such as auto dealers'policy of making salespeople drive the brands they sell, or coca - cola allowing no pepsi products in corporate offices … are irrelevant. in this sense, a corporate culture of not supporting the competitor is not the same as a philosophy of " eating your own dog food ". the latter focuses on the functional aspects of the company's own product. dogfooding allows employees to test their company's products in real - life situations ; a perceived, but still controversial, advantage beyond marketing, which gives management a sense of how the product might be used — all before launch to consumers. in software development, dogfooding can occur in multiple stages : first, a stable version of the software is used with just a single new feature added. then, multiple new features can be combined into a single version of the software and tested together. this allows several validations before the software is released. the practice enables proactive resolution of potential inconsistency and dependency issues, especially when several developers or teams work on the same product. the risks of public dogfooding, specifically that a company may have difficulties using its own products, may reduce the frequency of publicized dogfooding. = = examples = = in february 1980,
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developers or teams work on the same product. the risks of public dogfooding, specifically that a company may have difficulties using its own products, may reduce the frequency of publicized dogfooding. = = examples = = in february 1980, apple computer president michael scott wrote a memo announcing effective immediately!! no more typewriters are to be purchased, leased etc., etc. [ … ] we believe the typewriter is obsolete. let's prove it inside before we try and convince our customers. he set a goal to remove all typewriters from the company by 1 january 1981. by 1987, atari corp. was in the process of using the atari st throughout the company. the development of windows nt at microsoft involved over 200 developers in small teams, and it was held together by dave cutler's february 1991 insistence on dogfooding. microsoft developed the operating system on computers running nt daily builds. the software was initially crash prone, but the immediate feedback of code breaking the build, the loss of pride, and the knowledge of impeding the work of others were all powerful motivators. windows developers would typically dogfood or self - host windows starting from the early ( alpha ) builds, while the rest of the employees would start from the more stable beta builds that were also available to msdn subscribers. in 2005, infoworld reported that a tour of microsoft's network operations center showed pretty much beyond a reasonable doubt that microsoft does run its 20, 000 - plus node, international network on 99 percent windows technology, including servers, workstations, and edge security. infoworld argued that microsoft's use of windows for its high - traffic operations tipped many doubters over to windows'side of the fence. microsoft's internal email system initially ran on xenix. the only employees using microsoft mail worked on the software itself, and used it as a client for xenix mail servers. when asked why microsoft used unix, it publicly moved to using microsoft exchange. during the 1993 - 1996 migration, the internal test environment was codenamed " dogfood ". in 1997, an email storm known as the bedlam dl3 incident made microsoft build more robust features into microsoft exchange server to avoid lost and duplicate emails and network and server down - time, although dogfooding is rarely so dramatic. a second email storm in 2006 was handled perfectly by the system. in 1999, hewlett - packard staff referred to a project using hp's own products as " project al
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down - time, although dogfooding is rarely so dramatic. a second email storm in 2006 was handled perfectly by the system. in 1999, hewlett - packard staff referred to a project using hp's own products as " project alpo " ( referring to a brand of dog food ). around the same time, mozilla also practised dogfooding under that exact name. government green public procurement that allows testing of proposed environmental policies has been compared to dogfooding. on 1 june 2011, youtube added a license feature to its video uploading service allowing users to choose between a standard or creative commons license. the license label was followed by the message " ( shh! – internal dogfood ) " that appeared on all youtube videos lacking commercial licensing. a youtube employee confirmed that this referred to products that are tested internally. oracle corporation stated that as of october 2016 it runs oracle linux with more than 42, 000 servers [ to ] support more than 4 million external users and 84, 000 internal users. more than 20, 000 developers at oracle use oracle linux. after the crowdstrike outages in july 2024, ceo adam meyers testified before the us congress that " dogfooding " ( increasing its internal testing before deployment ) was one measure the company had put in place to prevent future problems. = = criticisms and support = = forcing those who design products to actually use and rely on them is sometimes thought to improve quality and usability, but software developers may be blind to usability and may have knowledge to make software work that an end user will lack. microsoft's chief information officer noted in 2008 that, previously, we tended not to go through the actual customer experience. we were always upgrading from a beta, not from production disk to production disk. dogfooding may happen too early to be viable, and those forced to use the products may get used to applying workarounds or may assume that someone else has reported the problem. dogfooding may be unrealistic, as customers will always have a choice of different companies'products to use together, and the product may not be used as intended. the process can lead to a loss of productivity and demoralisation, or at its extreme to " not invented here " syndrome, i. e. only using internal products. in 1989, donald knuth published a paper recounting lessons from the development of his tex typesetting software, in which the benefits of the approach were mentioned : thus, i came to
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syndrome, i. e. only using internal products. in 1989, donald knuth published a paper recounting lessons from the development of his tex typesetting software, in which the benefits of the approach were mentioned : thus, i came to the conclusion that the designer of a new system must not only be the implementor and the first large - scale user ; the designer should also write the first user manual. the separation of any of these four components would have hurt tex significantly. if i had not participated fully in all these activities, literally hundreds of improvements would never have been made, because i would never have thought of them or perceived why they were important. = = alternative terms = = in 2007, jo hoppe, the cio of pegasystems, said that she uses the alternative phrase " drinking our own champagne ". novell's head of public relations bruce lowry, commenting on his company's use of linux and openoffice. org, said that he also prefers this phrase. in 2009, the new cio of microsoft, tony scott, argued that the phrase " dogfooding " was unappealing and should be replaced by " icecreaming ", with the aim of developing products as ice cream that our customers want to consume. a less controversial and common alternative term used in some contexts is self - hosting, where developers'workstations would, for instance, get updated automatically overnight to the latest daily build of the software or operating system on which they work. developers of ibm's mainframe operating systems have long used the term " eating our own cooking ". = = see also = = alpha test self - hosting software prototyping user innovation = = references = = = = external links = = what is the work of dogs in this country? ( joel spolsky on fogbugz's dogfooding, joel on software, 2001 - 05 - 05 )'chowing down on dogfood'( google dogfooding blogger )
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planetary science ( or more rarely, planetology ) is the scientific study of planets ( including earth ), celestial bodies ( such as moons, asteroids, comets ) and planetary systems ( in particular those of the solar system ) and the processes of their formation. it studies objects ranging in size from micrometeoroids to gas giants, with the aim of determining their composition, dynamics, formation, interrelations and history. it is a strongly interdisciplinary field, which originally grew from astronomy and earth science, and now incorporates many disciplines, including planetary geology, cosmochemistry, atmospheric science, physics, oceanography, hydrology, theoretical planetary science, glaciology, and exoplanetology. allied disciplines include space physics, when concerned with the effects of the sun on the bodies of the solar system, and astrobiology. there are interrelated observational and theoretical branches of planetary science. observational research can involve combinations of space exploration, predominantly with robotic spacecraft missions using remote sensing, and comparative, experimental work in earth - based laboratories. the theoretical component involves considerable computer simulation and mathematical modelling. planetary scientists are generally located in the astronomy and physics or earth sciences departments of universities or research centres, though there are several purely planetary science institutes worldwide. generally, planetary scientists study one of the earth sciences, astronomy, astrophysics, geophysics, or physics at the graduate level and concentrate their research in planetary science disciplines. there are several major conferences each year, and a wide range of peer reviewed journals. some planetary scientists work at private research centres and often initiate partnership research tasks. = = history = = the history of planetary science may be said to have begun with the ancient greek philosopher democritus, who is reported by hippolytus as saying the ordered worlds are boundless and differ in size, and that in some there is neither sun nor moon, but that in others, both are greater than with us, and yet with others more in number. and that the intervals between the ordered worlds are unequal, here more and there less, and that some increase, others flourish and others decay, and here they come into being and there they are eclipsed. but that they are destroyed by colliding with one another. and that some ordered worlds are bare of animals and plants and all water. in more modern times, planetary science began in astronomy, from studies of the unresolved planets. in this sense, the original planetary astronomer would be galileo, who discovered the four largest moons of jupiter, the mountains on the
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plants and all water. in more modern times, planetary science began in astronomy, from studies of the unresolved planets. in this sense, the original planetary astronomer would be galileo, who discovered the four largest moons of jupiter, the mountains on the moon, and first observed the rings of saturn, all objects of intense later study. galileo's study of the lunar mountains in 1609 also began the study of extraterrestrial landscapes : his observation " that the moon certainly does not possess a smooth and polished surface " suggested that it and other worlds might appear " just like the face of the earth itself ". advances in telescope construction and instrumental resolution gradually allowed increased identification of the atmospheric as well as surface details of the planets. the moon was initially the most heavily studied, due to its proximity to the earth, as it always exhibited elaborate features on its surface, and the technological improvements gradually produced more detailed lunar geological knowledge. in this scientific process, the main instruments were astronomical optical telescopes ( and later radio telescopes ) and finally robotic exploratory spacecraft, such as space probes. the solar system has now been relatively well - studied, and a good overall understanding of the formation and evolution of this planetary system exists. however, there are large numbers of unsolved questions, and the rate of new discoveries is very high, partly due to the large number of interplanetary spacecraft currently exploring the solar system. = = disciplines = = planetary science studies observational and theoretical astronomy, geology ( astrogeology ), atmospheric science, and an emerging subspecialty in planetary oceans, called planetary oceanography. = = = planetary astronomy = = = this is both an observational and a theoretical science. observational researchers are predominantly concerned with the study of the small bodies of the solar system : those that are observed by telescopes, both optical and radio, so that characteristics of these bodies such as shape, spin, surface materials and weathering are determined, and the history of their formation and evolution can be understood. theoretical planetary astronomy is concerned with dynamics : the application of the principles of celestial mechanics to the solar system and extrasolar planetary systems. observing exoplanets and determining their physical properties, exoplanetology, is a major area of research besides solar system studies. every planet has its own branch. = = = planetary geology = = = in planetary science, the term geology is used in its broadest sense, to mean the study of the surface and interior parts of planets and moons, from their core to their magnetosphere. the
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own branch. = = = planetary geology = = = in planetary science, the term geology is used in its broadest sense, to mean the study of the surface and interior parts of planets and moons, from their core to their magnetosphere. the best - known research topics of planetary geology deal with the planetary bodies in the near vicinity of the earth : the moon, and the two neighboring planets : venus and mars. of these, the moon was studied first, using methods developed earlier on the earth. planetary geology focuses on celestial objects that exhibit a solid surface or have significant solid physical states as part of their structure. planetary geology applies geology, geophysics and geochemistry to planetary bodies. = = = = planetary geomorphology = = = = geomorphology studies the features on planetary surfaces and reconstructs the history of their formation, inferring the physical processes that acted on the surface. planetary geomorphology includes the study of several classes of surface features : impact features ( multi - ringed basins, craters ) volcanic and tectonic features ( lava flows, fissures, rilles ) glacial features aeolian features space weathering – erosional effects generated by the harsh environment of space ( continuous micrometeorite bombardment, high - energy particle rain, impact gardening ). for example, the thin dust cover on the surface of the lunar regolith is a result of micrometeorite bombardment. hydrological features : the liquid involved can range from water to hydrocarbon and ammonia, depending on the location within the solar system. this category includes the study of paleohydrological features ( paleochannels, paleolakes ). the history of a planetary surface can be deciphered by mapping features from top to bottom according to their deposition sequence, as first determined on terrestrial strata by nicolas steno. for example, stratigraphic mapping prepared the apollo astronauts for the field geology they would encounter on their lunar missions. overlapping sequences were identified on images taken by the lunar orbiter program, and these were used to prepare a lunar stratigraphic column and geological map of the moon. = = = = cosmochemistry, geochemistry and petrology = = = = one of the main problems when generating hypotheses on the formation and evolution of objects in the solar system is the lack of samples that can be analyzed in the laboratory, where a large suite of tools are available, and the full body of knowledge derived from terrestrial geology can be
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generating hypotheses on the formation and evolution of objects in the solar system is the lack of samples that can be analyzed in the laboratory, where a large suite of tools are available, and the full body of knowledge derived from terrestrial geology can be brought to bear. direct samples from the moon, asteroids and mars are present on earth, removed from their parent bodies, and delivered as meteorites. some of these have suffered contamination from the oxidising effect of earth's atmosphere and the infiltration of the biosphere, but those meteorites collected in the last few decades from antarctica are almost entirely pristine. the different types of meteorites that originate from the asteroid belt cover almost all parts of the structure of differentiated bodies : meteorites even exist that come from the core - mantle boundary ( pallasites ). the combination of geochemistry and observational astronomy has also made it possible to trace the hed meteorites back to a specific asteroid in the main belt, 4 vesta. the comparatively few known martian meteorites have provided insight into the geochemical composition of the martian crust, although the unavoidable lack of information about their points of origin on the diverse martian surface has meant that they do not provide more detailed constraints on theories of the evolution of the martian lithosphere. as of july 24, 2013, 65 samples of martian meteorites have been discovered on earth. many were found in either antarctica or the sahara desert. during the apollo era, in the apollo program, 384 kilograms of lunar samples were collected and transported to the earth, and three soviet luna robots also delivered regolith samples from the moon. these samples provide the most comprehensive record of the composition of any solar system body besides the earth. the numbers of lunar meteorites are growing quickly in the last few years – as of april 2008 there are 54 meteorites that have been officially classified as lunar. eleven of these are from the us antarctic meteorite collection, 6 are from the japanese antarctic meteorite collection and the other 37 are from hot desert localities in africa, australia, and the middle east. the total mass of recognized lunar meteorites is close to 50 kg. = = = = planetary geophysics and space physics = = = = space probes made it possible to collect data in not only the visible light region but in other areas of the electromagnetic spectrum. the planets can be characterized by their force fields : gravity and their magnetic fields, which are studied through geophysics and space physics. measuring the changes in acceleration experienced by spacecraft as they orbit
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the visible light region but in other areas of the electromagnetic spectrum. the planets can be characterized by their force fields : gravity and their magnetic fields, which are studied through geophysics and space physics. measuring the changes in acceleration experienced by spacecraft as they orbit has allowed fine details of the gravity fields of the planets to be mapped. for example, in the 1970s, the gravity field disturbances above lunar maria were measured through lunar orbiters, which led to the discovery of concentrations of mass, mascons, beneath the imbrium, serenitatis, crisium, nectaris and humorum basins. if a planet's magnetic field is sufficiently strong, its interaction with the solar wind forms a magnetosphere around a planet. early space probes discovered the gross dimensions of the terrestrial magnetic field, which extends about 10 earth radii towards the sun. the solar wind, a stream of charged particles, streams out and around the terrestrial magnetic field, and continues behind the magnetic tail, hundreds of earth radii downstream. inside the magnetosphere, there are relatively dense regions of solar wind particles, the van allen radiation belts. planetary geophysics includes, but is not limited to, seismology and tectonophysics, geophysical fluid dynamics, mineral physics, geodynamics, mathematical geophysics, and geophysical surveying. = = = = planetary geodesy = = = = planetary geodesy ( also known as planetary geodetics ) deals with the measurement and representation of the planets of the solar system, their gravitational fields and geodynamic phenomena ( polar motion in three - dimensional, time - varying space ). the science of geodesy has elements of both astrophysics and planetary sciences. the shape of the earth is to a large extent the result of its rotation, which causes its equatorial bulge, and the competition of geologic processes such as the collision of plates and of vulcanism, resisted by the earth's gravity field. these principles can be applied to the solid surface of earth ( orogeny ; few mountains are higher than 10 km ( 6 mi ), few deep sea trenches deeper than that because quite simply, a mountain as tall as, for example, 15 km ( 9 mi ), would develop so much pressure at its base, due to gravity, that the rock there would become plastic, and the mountain would slump back to a height of roughly 10 km ( 6 mi ) in a geologically insignificant time. some or all of these geologic principles can be applied to other planets besides earth
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to gravity, that the rock there would become plastic, and the mountain would slump back to a height of roughly 10 km ( 6 mi ) in a geologically insignificant time. some or all of these geologic principles can be applied to other planets besides earth. for instance on mars, whose surface gravity is much less, the largest volcano, olympus mons, is 27 km ( 17 mi ) high at its peak, a height that could not be maintained on earth. the earth geoid is essentially the figure of the earth abstracted from its topographic features. therefore, the mars geoid ( areoid ) is essentially the figure of mars abstracted from its topographic features. surveying and mapping are two important fields of application of geodesy. = = = planetary atmospheric science = = = an atmosphere is an important transitional zone between the solid planetary surface and the higher rarefied ionizing and radiation belts. not all planets have atmospheres : their existence depends on the mass of the planet, and the planet's distance from the sun – too distant and frozen atmospheres occur. besides the four giant planets, three of the four terrestrial planets ( earth, venus, and mars ) have significant atmospheres. two moons have significant atmospheres : saturn's moon titan and neptune's moon triton. a tenuous atmosphere exists around mercury. the effects of the rotation rate of a planet about its axis can be seen in atmospheric streams and currents. seen from space, these features show as bands and eddies in the cloud system and are particularly visible on jupiter and saturn. = = = planetary oceanography = = = = = = exoplanetology = = = exoplanetology studies exoplanets, the planets existing outside our solar system. until recently, the means of studying exoplanets have been extremely limited, but with the current rate of innovation in research technology, exoplanetology has become a rapidly developing subfield of astronomy. = = comparative planetary science = = planetary science frequently makes use of the method of comparison to give a greater understanding of the object of study. this can involve comparing the dense atmospheres of earth and saturn's moon titan, the evolution of outer solar system objects at different distances from the sun, or the geomorphology of the surfaces of the terrestrial planets, to give only a few examples. the main comparison that can be made is to features on the earth, as it is much more accessible and allows a much greater range of measurements to be made. earth analog studies are particularly common in planetary
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terrestrial planets, to give only a few examples. the main comparison that can be made is to features on the earth, as it is much more accessible and allows a much greater range of measurements to be made. earth analog studies are particularly common in planetary geology, geomorphology, and also in atmospheric science. the use of terrestrial analogs was first described by gilbert ( 1886 ). = = in fiction = = in frank herbert's 1965 science fiction novel dune, the major secondary character liet - kynes serves as the " imperial planetologist " for the fictional planet arrakis, a position he inherited from his father pardot kynes. in this role, a planetologist is described as having skills of an ecologist, geologist, meteorologist, and biologist, as well as basic understandings of human sociology. the planetologists apply this expertise to the study of entire planets. in the dune series, planetologists are employed to understand planetary resources and to plan terraforming or other planetary - scale engineering projects. this fictional position in dune has had an impact on the discourse surrounding planetary science itself and is referred to by one author as a " touchstone " within the related disciplines. in one example, a publication by sybil p. seitzinger in the journal nature opens with a brief introduction on the fictional role in dune, and suggests we should consider appointing individuals with similar skills to liet - kynes to help with managing human activity on earth. = = professional activity = = = = = journals = = = = = = professional bodies = = = this non - exhaustive list includes those institutions and universities with major groups of people working in planetary science. alphabetical order is used. division for planetary sciences ( dps ) of the american astronomical society american geophysical union meteoritical society europlanet = = = = government space agencies = = = = canadian space agency ( csa ) china national space administration ( cnsa, people's republic of china ). centre national d'etudes spatiales french national centre of space research deutsches zentrum fur luft - und raumfahrt e. v., ( german : abbreviated dlr ), the german aerospace center european space agency ( esa ) indian space research organisation ( isro ) israel space agency ( isa ) italian space agency japan aerospace exploration agency ( jaxa ) nasa ( national aeronautics and space administration, united states of america ) jpl gsfc ames national space organization ( taiwan ). russian federal space agency uk space agency ( uksa )
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( isa ) italian space agency japan aerospace exploration agency ( jaxa ) nasa ( national aeronautics and space administration, united states of america ) jpl gsfc ames national space organization ( taiwan ). russian federal space agency uk space agency ( uksa ). = = = major conferences = = = lunar and planetary science conference ( lpsc ), organized by the lunar and planetary institute in houston. held annually since 1970, occurs in march. division for planetary sciences ( dps ) meeting held annually since 1970 at a different location each year, predominantly within the mainland us. occurs around october. american geophysical union ( agu ) annual fall meeting in december in san francisco. american geophysical union ( agu ) joint assembly ( co - sponsored with other societies ) in april – may, in various locations around the world. meteoritical society annual meeting, held during the northern hemisphere summer, generally alternating between north america and europe. european planetary science congress ( epsc ), held annually around september at a location within europe. smaller workshops and conferences on particular fields occur worldwide throughout the year. = = see also = = areography ( geography of mars ) planetary cartography planetary coordinate system selenography – study of the surface and physical features of the moon theoretical planetology timeline of solar system exploration = = references = = = = further reading = = carr, michael h., saunders, r. s., strom, r. g., wilhelms, d. e. 1984. the geology of the terrestrial planets. nasa. morrison, david. 1994. exploring planetary worlds. w. h. freeman. isbn 0 - 7167 - 5043 - 0 hargitai h et al. ( 2015 ) classification and characterization of planetary landforms. in : hargitai h ( ed ) encyclopedia of planetary landforms. springer. doi : 10. 1007 / 978 - 1 - 4614 - 3134 - 3 https : / / link. springer. com / content / pdf / bbm % 3a978 - 1 - 4614 - 3134 - 3 % 2f1. pdf hauber e et al. ( 2019 ) planetary geologic mapping. in : hargitai h ( ed ) planetary cartography and gis. springer. page d ( 2015 ) the geology of planetary landforms. in : hargitai h ( ed ) encyclopedia of planetary landforms. springer. rossi, a. p., van gasselt s ( eds ) ( 2018 ) planetary geology. springer
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Planetary geodesy
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( 2015 ) the geology of planetary landforms. in : hargitai h ( ed ) encyclopedia of planetary landforms. springer. rossi, a. p., van gasselt s ( eds ) ( 2018 ) planetary geology. springer = = external links = = planetary science research discoveries ( articles ) the planetary society ( world's largest space - interest group : see also their active news blog ) planetary exploration newsletter ( psi - published professional newsletter, weekly distribution ) women in planetary science ( professional networking and news )
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in mathematics, the relative interior of a set is a refinement of the concept of the interior, which is often more useful when dealing with low - dimensional sets placed in higher - dimensional spaces. formally, the relative interior of a set s { \ displaystyle s } ( denoted relint ( s ) { \ displaystyle \ operatorname { relint } ( s ) } ) is defined as its interior within the affine hull of s. { \ displaystyle s. } in other words, relint ( s ) : = { x ∈ s : there exists > 0 such that b ( x ) ∩ aff ( s ) ⊆ s }, { \ displaystyle \ operatorname { relint } ( s ) : = \ { x \ in s : { \ text { there exists } } \ epsilon > 0 { \ text { such that } } b _ { \ epsilon } ( x ) \ cap \ operatorname { aff } ( s ) \ subseteq s \ }, } where aff ( s ) { \ displaystyle \ operatorname { aff } ( s ) } is the affine hull of s, { \ displaystyle s, } and b ( x ) { \ displaystyle b _ { \ epsilon } ( x ) } is a ball of radius { \ displaystyle \ epsilon } centered on x { \ displaystyle x }. any metric can be used for the construction of the ball ; all metrics define the same set as the relative interior. a set is relatively open iff it is equal to its relative interior. note that when aff ( s ) { \ displaystyle \ operatorname { aff } ( s ) } is a closed subspace of the full vector space ( always the case when the full vector space is finite dimensional ) then being relatively closed is equivalent to being closed. for any convex set c ⊆ r n { \ displaystyle c \ subseteq \ mathbb { r } ^ { n } } the relative interior is equivalently defined as relint ( c ) : = { x ∈ c : for all y ∈ c, there exists some λ > 1 such that λ x + ( 1 − λ ) y ∈ c } = { x ∈ c : for all y = x ∈ c, there exists some z ∈ c such that x ∈ ( y, z ) }. { \ displaystyle { \ begin { aligned } \ operatorname { relint }
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Relative interior
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} = { x ∈ c : for all y = x ∈ c, there exists some z ∈ c such that x ∈ ( y, z ) }. { \ displaystyle { \ begin { aligned } \ operatorname { relint } ( c ) & : = \ { x \ in c : { \ text { for all } } y \ in c, { \ text { there exists some } } \ lambda > 1 { \ text { such that } } \ lambda x + ( 1 - \ lambda ) y \ in c \ } \ \ & = \ { x \ in c : { \ text { for all } } y \ neq x \ in c, { \ text { there exists some } } z \ in c { \ text { such that } } x \ in ( y, z ) \ }. \ end { aligned } } } where x ∈ ( y, z ) { \ displaystyle x \ in ( y, z ) } means that there exists some 0 < λ < 1 { \ displaystyle 0 < \ lambda < 1 } such that x = λ z + ( 1 − λ ) y { \ displaystyle x = \ lambda z + ( 1 - \ lambda ) y }. = = comparison to interior = = the interior of a point in an at least one - dimensional ambient space is empty, but its relative interior is the point itself. the interior of a line segment in an at least two - dimensional ambient space is empty, but its relative interior is the line segment without its endpoints. the interior of a disc in an at least three - dimensional ambient space is empty, but its relative interior is the same disc without its circular edge. = = properties = = = = see also = = interior ( topology ) – largest open subset of some given set algebraic interior – generalization of topological interior quasi - relative interior – generalization of algebraic interior = = references = = zalinescu, constantin ( 30 july 2002 ). convex analysis in general vector spaces. river edge, n. j. london : world scientific publishing. isbn 978 - 981 - 4488 - 15 - 0. mr 1921556. oclc 285163112 – via internet archive. = = further reading = = boyd, stephen ; lieven vandenberghe ( 2004 ). convex optimization. cambridge : cambridge university press. p. 23. isbn 0 - 521 - 83378 - 7.
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Relative interior
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