Manuel Arellano
- Published in print:
- 2003
- Published Online:
- July 2005
- ISBN:
- 9780199245284
- eISBN:
- 9780191602481
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/0199245282.001.0001
- Subject:
- Economics and Finance, Econometrics
This book reviews some of the main topics in panel data econometrics. It analyses econometric models with non-exogenous explanatory variables, and the problem of distinguishing between dynamic ...
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This book reviews some of the main topics in panel data econometrics. It analyses econometric models with non-exogenous explanatory variables, and the problem of distinguishing between dynamic responses and unobserved heterogeneity in panel data models. The book is divided into three parts. Part I deals with static models. Part II discusses pure time series models. Part III considers dynamic conditional models.Less
This book reviews some of the main topics in panel data econometrics. It analyses econometric models with non-exogenous explanatory variables, and the problem of distinguishing between dynamic responses and unobserved heterogeneity in panel data models. The book is divided into three parts. Part I deals with static models. Part II discusses pure time series models. Part III considers dynamic conditional models.
John Hicks
- Published in print:
- 1987
- Published Online:
- November 2003
- ISBN:
- 9780198772873
- eISBN:
- 9780191596438
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/0198772874.003.0003
- Subject:
- Economics and Finance, Macro- and Monetary Economics
Static theory has a place of its own as something more than a preliminary to dynamics. There are problems of applied economics where a static approach is perfectly appropriate. However, there are ...
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Static theory has a place of its own as something more than a preliminary to dynamics. There are problems of applied economics where a static approach is perfectly appropriate. However, there are others for which it is not appropriate. This chapter argues dynamic methods are needed for the study of such problems.Less
Static theory has a place of its own as something more than a preliminary to dynamics. There are problems of applied economics where a static approach is perfectly appropriate. However, there are others for which it is not appropriate. This chapter argues dynamic methods are needed for the study of such problems.
Franklin M. Fisher
- Published in print:
- 2006
- Published Online:
- January 2009
- ISBN:
- 9780199298839
- eISBN:
- 9780191711480
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199298839.003.0010
- Subject:
- Economics and Finance, History of Economic Thought
This chapter draws attention to the topic of stability in the 21st century, for it has not yet reached a ‘satisfactory’ conclusion. When rummaging into the equations of a theory — be it simple supply ...
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This chapter draws attention to the topic of stability in the 21st century, for it has not yet reached a ‘satisfactory’ conclusion. When rummaging into the equations of a theory — be it simple supply and demand equation — one always wants to know its stability properties in order to know the predictive power of models for scientific appraisals. Samuelson likened stability behavior to the soul and mind of business. It encompasses both statics and dynamics analyses, that is, instantaneous or timeless determination of economic variables by mutually interdependent relations. There is a formal dependence between comparative statics and dynamics, namely, the Correspondence Principle. Stability concerns are here to stay. All models of reality call upon them to assess their compatibility. Samuelson has grounded stability in dynamics, which is promising for the 21st century economics.Less
This chapter draws attention to the topic of stability in the 21st century, for it has not yet reached a ‘satisfactory’ conclusion. When rummaging into the equations of a theory — be it simple supply and demand equation — one always wants to know its stability properties in order to know the predictive power of models for scientific appraisals. Samuelson likened stability behavior to the soul and mind of business. It encompasses both statics and dynamics analyses, that is, instantaneous or timeless determination of economic variables by mutually interdependent relations. There is a formal dependence between comparative statics and dynamics, namely, the Correspondence Principle. Stability concerns are here to stay. All models of reality call upon them to assess their compatibility. Samuelson has grounded stability in dynamics, which is promising for the 21st century economics.
J. N. Reddy
- Published in print:
- 2004
- Published Online:
- January 2010
- ISBN:
- 9780198525295
- eISBN:
- 9780191711671
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198525295.001.0001
- Subject:
- Physics, Theoretical, Computational, and Statistical Physics
This book presents the theory and computer implementation of the finite element method as applied to nonlinear problems of heat transfer and similar field problems, fluid mechanics (flows of ...
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This book presents the theory and computer implementation of the finite element method as applied to nonlinear problems of heat transfer and similar field problems, fluid mechanics (flows of incompressible fluids), and solid mechanics (elasticity, beams and plates). Both geometric as well as material nonlinearities are considered, and static and transient (that is, time-dependent) responses are studied. Although there exist a number of books on nonlinear finite elements that serve as good references for engineers who are familiar with the subject and wish to learn advanced topics or the latest developments, there is currently no book that is suitable as a textbook for a first course on nonlinear finite element analysis. This book fills the void in the market, providing a clear understanding of the concepts of nonlinear finite element analyses through detailed theoretical formulations and computer implementation steps, examples and exercises, in a tutorial, user-oriented style. In addition, the book is a useful reference for industrial engineers and scientists, and serves as a prelude to more advanced books on the subject.Less
This book presents the theory and computer implementation of the finite element method as applied to nonlinear problems of heat transfer and similar field problems, fluid mechanics (flows of incompressible fluids), and solid mechanics (elasticity, beams and plates). Both geometric as well as material nonlinearities are considered, and static and transient (that is, time-dependent) responses are studied. Although there exist a number of books on nonlinear finite elements that serve as good references for engineers who are familiar with the subject and wish to learn advanced topics or the latest developments, there is currently no book that is suitable as a textbook for a first course on nonlinear finite element analysis. This book fills the void in the market, providing a clear understanding of the concepts of nonlinear finite element analyses through detailed theoretical formulations and computer implementation steps, examples and exercises, in a tutorial, user-oriented style. In addition, the book is a useful reference for industrial engineers and scientists, and serves as a prelude to more advanced books on the subject.
Mauro Fabrizio and Morro Angelo
- Published in print:
- 2003
- Published Online:
- September 2007
- ISBN:
- 9780198527008
- eISBN:
- 9780191713316
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198527008.003.0007
- Subject:
- Mathematics, Applied Mathematics
This chapter provides a wide class of mathematical problems which originates from the application of Maxwell’s differential equations to electromagnetic systems. Static, stationary, and transient ...
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This chapter provides a wide class of mathematical problems which originates from the application of Maxwell’s differential equations to electromagnetic systems. Static, stationary, and transient problems are investigated for dielectrics or conductors with instantaneous response or with memory, subject to various boundary conditions. The main concern is to establish existence, uniqueness, and stability of the solution. This objective is realized by applying different mathematical techniques both to adhere to the features of the model and to offer a profitable set of approaches.Less
This chapter provides a wide class of mathematical problems which originates from the application of Maxwell’s differential equations to electromagnetic systems. Static, stationary, and transient problems are investigated for dielectrics or conductors with instantaneous response or with memory, subject to various boundary conditions. The main concern is to establish existence, uniqueness, and stability of the solution. This objective is realized by applying different mathematical techniques both to adhere to the features of the model and to offer a profitable set of approaches.
Robert James Matthys
- Published in print:
- 2004
- Published Online:
- January 2010
- ISBN:
- 9780198529712
- eISBN:
- 9780191712791
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198529712.003.0003
- Subject:
- Physics, History of Physics
Making a pendulum bigger or smaller involves more than just a linear scaling up or down of the pendulum's dimensions. If you want to make a larger or smaller pendulum than the one you have now, how ...
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Making a pendulum bigger or smaller involves more than just a linear scaling up or down of the pendulum's dimensions. If you want to make a larger or smaller pendulum than the one you have now, how should the dimensions change? It turns out that not all of the dimensions should change linearly with pendulum length. The free length of the suspension spring should be scaled directly proportional to the pendulum's length. James has shown that the vertical distance from the pendulum's axis of rotation up to the free top edge of the suspension spring is directly proportional to the spring's thickness. So the spring's thickness is then scaled directly proportional to the suspension spring's length (and incidentally, also directly proportional to the pendulum's length also). The suspension spring's width is adjusted to keep the static and bending stresses approximately constant for all pendulum lengths.Less
Making a pendulum bigger or smaller involves more than just a linear scaling up or down of the pendulum's dimensions. If you want to make a larger or smaller pendulum than the one you have now, how should the dimensions change? It turns out that not all of the dimensions should change linearly with pendulum length. The free length of the suspension spring should be scaled directly proportional to the pendulum's length. James has shown that the vertical distance from the pendulum's axis of rotation up to the free top edge of the suspension spring is directly proportional to the spring's thickness. So the spring's thickness is then scaled directly proportional to the suspension spring's length (and incidentally, also directly proportional to the pendulum's length also). The suspension spring's width is adjusted to keep the static and bending stresses approximately constant for all pendulum lengths.
Morwenna Ludlow
- Published in print:
- 2007
- Published Online:
- January 2008
- ISBN:
- 9780199280766
- eISBN:
- 9780191712906
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199280766.003.0021
- Subject:
- Religion, Early Christian Studies
This concluding chapter draws together some more general answers to the question of why Gregory has been interpreted in so many different ways, first looking at the question from the perspective of ...
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This concluding chapter draws together some more general answers to the question of why Gregory has been interpreted in so many different ways, first looking at the question from the perspective of Gregory's readers and secondly by focussing on Gregory himself as a writer. It suggests that most accounts of Christian theology implicitly rely on one of three broad historiographical models. The first is the ‘static’ model, which views both theology and the Church as basically unchanging and thus also tends to see the development of doctrine in terms of the working-out of the logical implications of the first revelations of truths about God. The second is the ‘reformatory’ model, which shares with the static model a high evaluation of the original revelation of divine truth, but unlike it thinks that at some point the original revelation became degraded to such an extent that it was held by no Christian group in a satisfactory form. The thirds is the ‘ adaptive’ model — Christianity also changes across time, but not according to a pattern of original truth, fall, and reform.Less
This concluding chapter draws together some more general answers to the question of why Gregory has been interpreted in so many different ways, first looking at the question from the perspective of Gregory's readers and secondly by focussing on Gregory himself as a writer. It suggests that most accounts of Christian theology implicitly rely on one of three broad historiographical models. The first is the ‘static’ model, which views both theology and the Church as basically unchanging and thus also tends to see the development of doctrine in terms of the working-out of the logical implications of the first revelations of truths about God. The second is the ‘reformatory’ model, which shares with the static model a high evaluation of the original revelation of divine truth, but unlike it thinks that at some point the original revelation became degraded to such an extent that it was held by no Christian group in a satisfactory form. The thirds is the ‘ adaptive’ model — Christianity also changes across time, but not according to a pattern of original truth, fall, and reform.
Tatiana Sitnikova, Phillip J. Holcomb, and Gina R. Kuperberg
- Published in print:
- 2008
- Published Online:
- May 2008
- ISBN:
- 9780195188370
- eISBN:
- 9780199870462
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195188370.003.0026
- Subject:
- Psychology, Cognitive Neuroscience
This chapter begins with a discussion of evidence for distinctions between two semantic comprehension systems in the language domain: a system that maps the perceived information on graded semantic ...
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This chapter begins with a discussion of evidence for distinctions between two semantic comprehension systems in the language domain: a system that maps the perceived information on graded semantic representations and a system that utilizes particular semantic requirements of verbs. It then reviews similar research using static and motion pictures. It argues that the two mechanisms of language comprehension might be analogous to the systems that use graded semantic representations and action-based requirements to make sense of the visual world. The experiments that are reviewed in this chapter examine questions of both how comprehenders understand relationships between the elements within individual events and how they understand the relationships between events. Experiments that have used event-related potentials (ERPs) are also highlighted.Less
This chapter begins with a discussion of evidence for distinctions between two semantic comprehension systems in the language domain: a system that maps the perceived information on graded semantic representations and a system that utilizes particular semantic requirements of verbs. It then reviews similar research using static and motion pictures. It argues that the two mechanisms of language comprehension might be analogous to the systems that use graded semantic representations and action-based requirements to make sense of the visual world. The experiments that are reviewed in this chapter examine questions of both how comprehenders understand relationships between the elements within individual events and how they understand the relationships between events. Experiments that have used event-related potentials (ERPs) are also highlighted.
V. E. Fortov, I. T. Iakubov, and A. G. Khrapak
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780199299805
- eISBN:
- 9780191714948
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199299805.003.0005
- Subject:
- Physics, Nuclear and Plasma Physics
The description of the thermodynamics of the strongly ionized plasma starts by discussing the most popular and well-studied model of the one-component plasma (OCP), which represents a system of point ...
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The description of the thermodynamics of the strongly ionized plasma starts by discussing the most popular and well-studied model of the one-component plasma (OCP), which represents a system of point ions placed in a homogeneous medium of charges of opposite sign. The results of calculations by the Monte Carlo method of the binary correlation function, static structure factor, dielectric permeability, isothermal compressibility, and internal and free energies are presented. The region of existence of Wigner crystallization is determined. Pseudopotential models of multicomponent plasma are considered. The advantages and disadvantages of the quasiclassical approximation, density functional, and quantum Monte Carlo methods are discussed. A number of the proposed models in the region of increased nonideality lose thermodynamic stability, which is attributed to the possibility of a phase transition and the separation of the system into phases of different densities.Less
The description of the thermodynamics of the strongly ionized plasma starts by discussing the most popular and well-studied model of the one-component plasma (OCP), which represents a system of point ions placed in a homogeneous medium of charges of opposite sign. The results of calculations by the Monte Carlo method of the binary correlation function, static structure factor, dielectric permeability, isothermal compressibility, and internal and free energies are presented. The region of existence of Wigner crystallization is determined. Pseudopotential models of multicomponent plasma are considered. The advantages and disadvantages of the quasiclassical approximation, density functional, and quantum Monte Carlo methods are discussed. A number of the proposed models in the region of increased nonideality lose thermodynamic stability, which is attributed to the possibility of a phase transition and the separation of the system into phases of different densities.
John Hicks
- Published in print:
- 1987
- Published Online:
- November 2003
- ISBN:
- 9780198772873
- eISBN:
- 9780191596438
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/0198772874.003.0002
- Subject:
- Economics and Finance, Macro- and Monetary Economics
This chapter discusses the concept of equilibrium in a static economy. The static economy (in which wants are unchanging, and resources unchanging) is in a state of equilibrium when all the ...
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This chapter discusses the concept of equilibrium in a static economy. The static economy (in which wants are unchanging, and resources unchanging) is in a state of equilibrium when all the ‘individuals’ in it are choosing those quantities, which, out of the alternatives available to them, they prefer to produce and to consume. The crucial assumption of static theory (without which idea of the static economy could not have been developed as it has been developed) is that a static economy (static, because tastes and resources are unchanging) can be treated as if it were in equilibrium: the quantities produced and consumed will be (near enough) the equilibrium quantities that have just been described.Less
This chapter discusses the concept of equilibrium in a static economy. The static economy (in which wants are unchanging, and resources unchanging) is in a state of equilibrium when all the ‘individuals’ in it are choosing those quantities, which, out of the alternatives available to them, they prefer to produce and to consume. The crucial assumption of static theory (without which idea of the static economy could not have been developed as it has been developed) is that a static economy (static, because tastes and resources are unchanging) can be treated as if it were in equilibrium: the quantities produced and consumed will be (near enough) the equilibrium quantities that have just been described.
John Hicks
- Published in print:
- 1987
- Published Online:
- November 2003
- ISBN:
- 9780198772873
- eISBN:
- 9780191596438
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/0198772874.003.0005
- Subject:
- Economics and Finance, Macro- and Monetary Economics
This chapter discusses the method of Marshall. Marshall knew that static method (hitherto the only method of economic theory) led, when carried right through, to the stationary state, and no further. ...
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This chapter discusses the method of Marshall. Marshall knew that static method (hitherto the only method of economic theory) led, when carried right through, to the stationary state, and no further. The theory of a stationary state seemed to him to be of little interest; if it was worthwhile to elaborate it at all, that was chiefly in order that it should not be mistaken for something else. What then was to be done? There was, he thought, no alternative to statics. If a complete static theory led nowhere, we must make do with an incomplete static theory. That, in short, is the method of Marshall. There is no question that it is a powerful method; for many problems of economics it is as good a method as we are likely to get. It is not at all a dynamic method; it is a resuscitation of statics. It was a special method which would only work in special cases. It would only work so long as the things that had been put into the ‘pound’ would stay there.Less
This chapter discusses the method of Marshall. Marshall knew that static method (hitherto the only method of economic theory) led, when carried right through, to the stationary state, and no further. The theory of a stationary state seemed to him to be of little interest; if it was worthwhile to elaborate it at all, that was chiefly in order that it should not be mistaken for something else. What then was to be done? There was, he thought, no alternative to statics. If a complete static theory led nowhere, we must make do with an incomplete static theory. That, in short, is the method of Marshall. There is no question that it is a powerful method; for many problems of economics it is as good a method as we are likely to get. It is not at all a dynamic method; it is a resuscitation of statics. It was a special method which would only work in special cases. It would only work so long as the things that had been put into the ‘pound’ would stay there.
Walter van de Leur
- Published in print:
- 2002
- Published Online:
- September 2008
- ISBN:
- 9780195124484
- eISBN:
- 9780199868711
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195124484.003.0009
- Subject:
- Music, History, Western
This chapter plots the development in Strayhorn’s later arranging and composing. By the mid-1950s, Strayhorn had expanded his music writing with numerous individual elements into a mature and ...
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This chapter plots the development in Strayhorn’s later arranging and composing. By the mid-1950s, Strayhorn had expanded his music writing with numerous individual elements into a mature and distinctive style that showed an increased complexity on all levels, while at the same time it had an unsurpassed emotional quality. The chapter looks at the most important components in his later-year composing, including chromaticism, melodic cells, classical construction, angular lines, static harmony, harmonic ambiguity, complex modulations, widened tonality, linear and through-composed forms, multiple-thematic writing, complex through-imitation, clusters, layering of chords, and rhythmic gestures. Examples are drawn from Cashmere Cutie, Pretty Girl, U.M.M.G., Ballad for Very Tired and Very Sad Lotus Eaters, Up and Down, Orson, Day Dream, and Take the “A” Train (1956).Less
This chapter plots the development in Strayhorn’s later arranging and composing. By the mid-1950s, Strayhorn had expanded his music writing with numerous individual elements into a mature and distinctive style that showed an increased complexity on all levels, while at the same time it had an unsurpassed emotional quality. The chapter looks at the most important components in his later-year composing, including chromaticism, melodic cells, classical construction, angular lines, static harmony, harmonic ambiguity, complex modulations, widened tonality, linear and through-composed forms, multiple-thematic writing, complex through-imitation, clusters, layering of chords, and rhythmic gestures. Examples are drawn from Cashmere Cutie, Pretty Girl, U.M.M.G., Ballad for Very Tired and Very Sad Lotus Eaters, Up and Down, Orson, Day Dream, and Take the “A” Train (1956).
Marian Klamer
- Published in print:
- 2008
- Published Online:
- January 2009
- ISBN:
- 9780199238385
- eISBN:
- 9780191716768
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199238385.003.0009
- Subject:
- Linguistics, Semantics and Pragmatics
This chapter discusses semantic parameters relevant to the alignment systems of nine lesser-known languages of eastern Indonesia. The alignment is primarily determined by the proto-Agent feature ...
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This chapter discusses semantic parameters relevant to the alignment systems of nine lesser-known languages of eastern Indonesia. The alignment is primarily determined by the proto-Agent feature ‘volition’ and the proto-Patient feature ‘undergoer of change of state’. The distinction between dynamic and static predicates plays only a limited role.Less
This chapter discusses semantic parameters relevant to the alignment systems of nine lesser-known languages of eastern Indonesia. The alignment is primarily determined by the proto-Agent feature ‘volition’ and the proto-Patient feature ‘undergoer of change of state’. The distinction between dynamic and static predicates plays only a limited role.
Ian P. Howard and Brian J. Rogers
- Published in print:
- 2008
- Published Online:
- May 2009
- ISBN:
- 9780195367607
- eISBN:
- 9780199867264
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195367607.003.0024
- Subject:
- Psychology, Cognitive Neuroscience, Cognitive Psychology
This chapter reviews static monocular cues to depth. Topics covered include syntax of edges, corners, and surfaces; interposition, shading and shadows; accommodation and image blur; and vergence as a ...
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This chapter reviews static monocular cues to depth. Topics covered include syntax of edges, corners, and surfaces; interposition, shading and shadows; accommodation and image blur; and vergence as a cue to distance.Less
This chapter reviews static monocular cues to depth. Topics covered include syntax of edges, corners, and surfaces; interposition, shading and shadows; accommodation and image blur; and vergence as a cue to distance.
Marie-Anne Mayoux-Benhamou, Marc Wybier, Jacques Patrick Barbet, Sylvain Labbé, and Michel Revel
- Published in print:
- 1992
- Published Online:
- March 2012
- ISBN:
- 9780195068207
- eISBN:
- 9780199847198
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195068207.003.0020
- Subject:
- Neuroscience, Sensory and Motor Systems
Neck muscles have both dynamic and static functionalities, since they move the head in all directions and since they also have a postural role as antagonists of gravity. The static function depends ...
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Neck muscles have both dynamic and static functionalities, since they move the head in all directions and since they also have a postural role as antagonists of gravity. The static function depends on the strength and endurance of these muscles. The spine is a single weight-bearing column, and it depends solely upon muscular strength for both its lateral and its anteroposterior stabilization. The normal curvature observed in the sagittal plane is constantly subject to gravitational torques, which tends to increase lordosis and cause the head to fall forward. The neck muscles must work against these two effects of gravity. Calculating the absolute force given by neck muscles in static situations needs an accurate knowledge of forces present and of lever arms involved.Less
Neck muscles have both dynamic and static functionalities, since they move the head in all directions and since they also have a postural role as antagonists of gravity. The static function depends on the strength and endurance of these muscles. The spine is a single weight-bearing column, and it depends solely upon muscular strength for both its lateral and its anteroposterior stabilization. The normal curvature observed in the sagittal plane is constantly subject to gravitational torques, which tends to increase lordosis and cause the head to fall forward. The neck muscles must work against these two effects of gravity. Calculating the absolute force given by neck muscles in static situations needs an accurate knowledge of forces present and of lever arms involved.
Gary Goertz and James Mahoney
- Published in print:
- 2012
- Published Online:
- October 2017
- ISBN:
- 9780691149707
- eISBN:
- 9781400845446
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691149707.003.0005
- Subject:
- Sociology, Social Research and Statistics
This chapter shows that the quantitative and qualitative cultures differ on the issue of symmetry. Whereas quantitative research tends to analyze relationships that are symmetric, qualitative ...
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This chapter shows that the quantitative and qualitative cultures differ on the issue of symmetry. Whereas quantitative research tends to analyze relationships that are symmetric, qualitative research focuses on relationships that have asymmetric qualities. Causal models and explanations can be asymmetric in a variety of ways. This chapter deals mainly (though not exclusively) on the so-called “static causal asymmetry,” in which the explanation of occurrence is not the mirror image of that of nonoccurrence. After comparing symmetric and asymmetric models, the chapter looks at examples of asymmetric explanations using set-theoretic causal models. It highlights the difficulty of translating the fundamental symmetry of standard statistical models into the basic asymmetry of set-theoretic models, as well as the difficulty of capturing the asymmetry of set-theoretic models with the standard symmetric tools of statistics.Less
This chapter shows that the quantitative and qualitative cultures differ on the issue of symmetry. Whereas quantitative research tends to analyze relationships that are symmetric, qualitative research focuses on relationships that have asymmetric qualities. Causal models and explanations can be asymmetric in a variety of ways. This chapter deals mainly (though not exclusively) on the so-called “static causal asymmetry,” in which the explanation of occurrence is not the mirror image of that of nonoccurrence. After comparing symmetric and asymmetric models, the chapter looks at examples of asymmetric explanations using set-theoretic causal models. It highlights the difficulty of translating the fundamental symmetry of standard statistical models into the basic asymmetry of set-theoretic models, as well as the difficulty of capturing the asymmetry of set-theoretic models with the standard symmetric tools of statistics.
A. Schmidt-Rhaesa
- Published in print:
- 2007
- Published Online:
- September 2007
- ISBN:
- 9780198566687
- eISBN:
- 9780191718007
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198566687.003.0007
- Subject:
- Biology, Evolutionary Biology / Genetics
There is a wide variety of different sensory organs, but the basic principles of their function are similar. This chapter summarizes the known sensory structures, and ciliary receptors are briefly ...
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There is a wide variety of different sensory organs, but the basic principles of their function are similar. This chapter summarizes the known sensory structures, and ciliary receptors are briefly discussed. The two sensory structures discussed in detail are static sense organs and photoreceptors. Static sensory organs occur as statocysts in a variety of animals. They differ extremely in shape, composition, and location, making their multiple parallel evolution quite likely. Photoreceptors also occur in abundance and in different forms. Following a review of photoreceptors among animal taxa, it is concluded that the molecular photosensitive system is quite old and that it is, for example, likely that several opsins were present in the bilaterian ancestor. The particular architecture of the photoreceptor (‘eye’) evolved in parallel many times over.Less
There is a wide variety of different sensory organs, but the basic principles of their function are similar. This chapter summarizes the known sensory structures, and ciliary receptors are briefly discussed. The two sensory structures discussed in detail are static sense organs and photoreceptors. Static sensory organs occur as statocysts in a variety of animals. They differ extremely in shape, composition, and location, making their multiple parallel evolution quite likely. Photoreceptors also occur in abundance and in different forms. Following a review of photoreceptors among animal taxa, it is concluded that the molecular photosensitive system is quite old and that it is, for example, likely that several opsins were present in the bilaterian ancestor. The particular architecture of the photoreceptor (‘eye’) evolved in parallel many times over.
Helmut Hofmann
- Published in print:
- 2008
- Published Online:
- September 2008
- ISBN:
- 9780198504016
- eISBN:
- 9780191708480
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198504016.003.0022
- Subject:
- Physics, Nuclear and Plasma Physics
This chapter presents the basic elements of statistical mechanics, and derives differential laws of thermostatics of deformed nuclei. Adiabatic and isothermal susceptibilities are introduced. Density ...
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This chapter presents the basic elements of statistical mechanics, and derives differential laws of thermostatics of deformed nuclei. Adiabatic and isothermal susceptibilities are introduced. Density operators for generalized ensembles are defined, from which various extremal properties are deduced, together with the second law and the meaning of quasi-static processes. Level densities and energy distributions are discussed, for which the Darwin-Fowler procedure and Gaussian approximations are introduced, respectively. Such methods allow for simple but realistic estimates of fluctuations of energy and temperature, and thus help to understand the applicability of the canonical ensemble to nuclei as isolated and self-bound systems. This property reflects itself in inherent uncertainties in the value of temperature, as expressed most clearly by a thermal uncertainty relation. Likewise, there is the obvious lack of extensivity, which is believed to lead to negative specific heats. A critical review upon these issues is given. Finally, general formulas for thermostatic potentials of independent particles are derived.Less
This chapter presents the basic elements of statistical mechanics, and derives differential laws of thermostatics of deformed nuclei. Adiabatic and isothermal susceptibilities are introduced. Density operators for generalized ensembles are defined, from which various extremal properties are deduced, together with the second law and the meaning of quasi-static processes. Level densities and energy distributions are discussed, for which the Darwin-Fowler procedure and Gaussian approximations are introduced, respectively. Such methods allow for simple but realistic estimates of fluctuations of energy and temperature, and thus help to understand the applicability of the canonical ensemble to nuclei as isolated and self-bound systems. This property reflects itself in inherent uncertainties in the value of temperature, as expressed most clearly by a thermal uncertainty relation. Likewise, there is the obvious lack of extensivity, which is believed to lead to negative specific heats. A critical review upon these issues is given. Finally, general formulas for thermostatic potentials of independent particles are derived.
Helmut Hofmann
- Published in print:
- 2008
- Published Online:
- September 2008
- ISBN:
- 9780198504016
- eISBN:
- 9780191708480
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198504016.003.0024
- Subject:
- Physics, Nuclear and Plasma Physics
This chapter presents a short review of path integrals in quantum mechanics. This is followed by a detailed discussion of the evaluation of the semi-classical propagator, involving quadratic ...
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This chapter presents a short review of path integrals in quantum mechanics. This is followed by a detailed discussion of the evaluation of the semi-classical propagator, involving quadratic expansions of the action and the calculation of determinants. The concept of functionals is introduced for multi-dimensional cases, using a system linearly coupled to many oscillators as an example. The use of path integrals in statistical mechanics is described and quantum corrections to the classical limit are obtained. The connection with Green functions and level density is presented, with an excursion to periodic orbit theory and to the Gutzwiller formula for the oscillating part of the single particle level density. Many-body systems with separable interactions are treated by the Hubbard-Stratonovich transformation. For quantum corrections to the partition function, the static- and perturbed static path approximations are developed. The breakdown for unstable modes is discussed and a possible extension to damped motion is sketched.Less
This chapter presents a short review of path integrals in quantum mechanics. This is followed by a detailed discussion of the evaluation of the semi-classical propagator, involving quadratic expansions of the action and the calculation of determinants. The concept of functionals is introduced for multi-dimensional cases, using a system linearly coupled to many oscillators as an example. The use of path integrals in statistical mechanics is described and quantum corrections to the classical limit are obtained. The connection with Green functions and level density is presented, with an excursion to periodic orbit theory and to the Gutzwiller formula for the oscillating part of the single particle level density. Many-body systems with separable interactions are treated by the Hubbard-Stratonovich transformation. For quantum corrections to the partition function, the static- and perturbed static path approximations are developed. The breakdown for unstable modes is discussed and a possible extension to damped motion is sketched.
Sergey N. Dorogovtsev
- Published in print:
- 2010
- Published Online:
- May 2010
- ISBN:
- 9780199548927
- eISBN:
- 9780191720574
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199548927.003.0005
- Subject:
- Physics, Theoretical, Computational, and Statistical Physics
This chapter considers networks with an arbitrary degree distribution, in which the degrees of nodes are uncorrelated, including the degrees of the nearest-neighbour nodes. The two kinds of these ...
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This chapter considers networks with an arbitrary degree distribution, in which the degrees of nodes are uncorrelated, including the degrees of the nearest-neighbour nodes. The two kinds of these networks are considered in detail. The first is the configuration model (a random graph with a given degree sequence) and the second is the static model (a random graph with a given sequence of desired degrees). The basic properties of these locally tree-like networks are discussed. The chapter also considers bipartite uncorrelated networks.Less
This chapter considers networks with an arbitrary degree distribution, in which the degrees of nodes are uncorrelated, including the degrees of the nearest-neighbour nodes. The two kinds of these networks are considered in detail. The first is the configuration model (a random graph with a given degree sequence) and the second is the static model (a random graph with a given sequence of desired degrees). The basic properties of these locally tree-like networks are discussed. The chapter also considers bipartite uncorrelated networks.
