Naomi E. Chayen, John R. Helliwell, and Edward H. Snell
- Published in print:
- 2010
- Published Online:
- May 2010
- ISBN:
- 9780199213252
- eISBN:
- 9780191707575
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199213252.001.0001
- Subject:
- Physics, Crystallography
Structural crystallography provides key information to understand the mechanism involved for biological processes. The technique requires high‐quality crystals. The book Macromolecular ...
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Structural crystallography provides key information to understand the mechanism involved for biological processes. The technique requires high‐quality crystals. The book Macromolecular crystallization and crystal perfection covers the techniques to get these high quality crystals and then obtain the best structural data from them. We focus on two areas, the crystal and the diffraction experiment. We briefly address crystallization theory and then focus on practical crystallization strategies discussing screening and optimization. Where high quality crystals are not initially obtained, remediation strategies and alternative approaches are discussed. Diffraction is covered from both the X‐ray and neutron viewpoint. A physical analysis of long and short‐range order is used to explain features seen in the diffraction pattern and the causes of those features. Diffraction disorders are discussed. Factors that cause degradation to the diffraction and strategies to mitigate those factors are addressed. We then address beamline and detector optimization as a means to improve the data quality. Crystallization is still a largely empirical process and our final chapters focus on the use of powder methods, where crystals are small, complementary techniques where we have no crystals at all and what the future holds with the advent of fourth generation X‐ray sources. Overall the book is aimed at both more experienced researchers and graduate students. We aim for it to become a reference work for all researchers in these interdisciplinary subjects on these topics.Less
Structural crystallography provides key information to understand the mechanism involved for biological processes. The technique requires high‐quality crystals. The book Macromolecular crystallization and crystal perfection covers the techniques to get these high quality crystals and then obtain the best structural data from them. We focus on two areas, the crystal and the diffraction experiment. We briefly address crystallization theory and then focus on practical crystallization strategies discussing screening and optimization. Where high quality crystals are not initially obtained, remediation strategies and alternative approaches are discussed. Diffraction is covered from both the X‐ray and neutron viewpoint. A physical analysis of long and short‐range order is used to explain features seen in the diffraction pattern and the causes of those features. Diffraction disorders are discussed. Factors that cause degradation to the diffraction and strategies to mitigate those factors are addressed. We then address beamline and detector optimization as a means to improve the data quality. Crystallization is still a largely empirical process and our final chapters focus on the use of powder methods, where crystals are small, complementary techniques where we have no crystals at all and what the future holds with the advent of fourth generation X‐ray sources. Overall the book is aimed at both more experienced researchers and graduate students. We aim for it to become a reference work for all researchers in these interdisciplinary subjects on these topics.
Simon Scott
- Published in print:
- 2010
- Published Online:
- January 2011
- ISBN:
- 9780198568360
- eISBN:
- 9780191594748
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198568360.003.0005
- Subject:
- Mathematics, Analysis
In this chapter details of the construction of the fundamental trace functionals on pseudodifferential operators are given. The approach to traces taken here is through an analysis of the singularity ...
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In this chapter details of the construction of the fundamental trace functionals on pseudodifferential operators are given. The approach to traces taken here is through an analysis of the singularity structure of the operator Schwartz kernel. This allows for a dual perspective on traces, viewed either from the microanalytic approach of pseudodifferential methods or from the approach favoured in applications in geometric analysis, differential geometry, and theoretical physics, of subtracting-off the singular part of the kernel. Regularized traces arise via subtracting-off from the Schwartz kernel the meromorphic continuation of homogeneous distributions defined by the pseudodifferential operator symbol, linking trace regularization methods with traditional distributional analysis. Exact formulae are computed for regularized trace functionals for log-classical pseudodifferential operators, allowing, in particular, precise formulae for the zeta determinant. The final part of the chapter analyses the principal multiplicative functional on the semiqroup of pseudodifferential operators.Less
In this chapter details of the construction of the fundamental trace functionals on pseudodifferential operators are given. The approach to traces taken here is through an analysis of the singularity structure of the operator Schwartz kernel. This allows for a dual perspective on traces, viewed either from the microanalytic approach of pseudodifferential methods or from the approach favoured in applications in geometric analysis, differential geometry, and theoretical physics, of subtracting-off the singular part of the kernel. Regularized traces arise via subtracting-off from the Schwartz kernel the meromorphic continuation of homogeneous distributions defined by the pseudodifferential operator symbol, linking trace regularization methods with traditional distributional analysis. Exact formulae are computed for regularized trace functionals for log-classical pseudodifferential operators, allowing, in particular, precise formulae for the zeta determinant. The final part of the chapter analyses the principal multiplicative functional on the semiqroup of pseudodifferential operators.
Nasr Ghoniem and Daniel Walgraef
- Published in print:
- 2008
- Published Online:
- May 2008
- ISBN:
- 9780199298686
- eISBN:
- 9780191720222
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199298686.001.0001
- Subject:
- Physics, Condensed Matter Physics / Materials
In materials, critical phenomena such as phase transitions, plastic deformation and fracture are intimately related to self-organization. Understanding the origin of spatio-temporal order in systems ...
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In materials, critical phenomena such as phase transitions, plastic deformation and fracture are intimately related to self-organization. Understanding the origin of spatio-temporal order in systems far from thermal equilibrium and the selection mechanisms of spatial structures and their symmetries is a major theme of present day research on the structure of continuous matter. Furthermore, the development of methods for producing spatially-ordered and self-assembled microstructure in solids by non-equilibrium methods opens the door to many technological applications. In order to describe and understand the behaviour of such materials, dynamical concepts related to non-equilibrium phenomena, irreversible thermodynamics, nonlinear dynamics, and bifurcation theory, are required. The generic presence of defects and their crucial influence on pattern formation and critical phenomena in extended systems is now well-established. Similar to observations in hydrodynamical, liquid crystal, and laser systems, defects in materials have a profound effect. This book is divided into two volumes. The first volume is devoted to the most basic concepts of the physics, mechanics, and mathematical theory utilized in the analysis of non-equilibrium materials. The book presents a background on material deformation, defect theory, transport processes, and the statistical mechanics and thermodynamics of phase transitions. Mathematical concepts of non-linear dynamics, such as bifurcation and instability theory, the dynamics of complex systems near pattern forming instabilities, the generic aspects of pattern formation, selection and stability are presented. Stochastic and numerical methods used in this field are also introduced. The methods and techniques developed in the first volume are applied in the second volume to specific problems in various advanced technologies.Less
In materials, critical phenomena such as phase transitions, plastic deformation and fracture are intimately related to self-organization. Understanding the origin of spatio-temporal order in systems far from thermal equilibrium and the selection mechanisms of spatial structures and their symmetries is a major theme of present day research on the structure of continuous matter. Furthermore, the development of methods for producing spatially-ordered and self-assembled microstructure in solids by non-equilibrium methods opens the door to many technological applications. In order to describe and understand the behaviour of such materials, dynamical concepts related to non-equilibrium phenomena, irreversible thermodynamics, nonlinear dynamics, and bifurcation theory, are required. The generic presence of defects and their crucial influence on pattern formation and critical phenomena in extended systems is now well-established. Similar to observations in hydrodynamical, liquid crystal, and laser systems, defects in materials have a profound effect. This book is divided into two volumes. The first volume is devoted to the most basic concepts of the physics, mechanics, and mathematical theory utilized in the analysis of non-equilibrium materials. The book presents a background on material deformation, defect theory, transport processes, and the statistical mechanics and thermodynamics of phase transitions. Mathematical concepts of non-linear dynamics, such as bifurcation and instability theory, the dynamics of complex systems near pattern forming instabilities, the generic aspects of pattern formation, selection and stability are presented. Stochastic and numerical methods used in this field are also introduced. The methods and techniques developed in the first volume are applied in the second volume to specific problems in various advanced technologies.
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/9780195367607.003.0012
- Subject:
- Psychology, Cognitive Neuroscience, Cognitive Psychology
Much can be learned about the visual system by studying clinical defects and abnormalities. This chapter reviews defects of depth perception that result from brain damage or genetic defects such as ...
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Much can be learned about the visual system by studying clinical defects and abnormalities. This chapter reviews defects of depth perception that result from brain damage or genetic defects such as albinism, with particular attention paid to the signs and symptoms of loss of binocularity. The discussions cover stereoanomalies; brain damage and stereopsis; abnormal interocular transfer; binocularity and proprioception; and albinism.Less
Much can be learned about the visual system by studying clinical defects and abnormalities. This chapter reviews defects of depth perception that result from brain damage or genetic defects such as albinism, with particular attention paid to the signs and symptoms of loss of binocularity. The discussions cover stereoanomalies; brain damage and stereopsis; abnormal interocular transfer; binocularity and proprioception; and albinism.
Eduard Feireisl
- Published in print:
- 2003
- Published Online:
- September 2007
- ISBN:
- 9780198528388
- eISBN:
- 9780191713590
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198528388.003.0004
- Subject:
- Mathematics, Applied Mathematics
The concept of a variational solution to the full Navier-Stokes-Fourier system is introduced in this chapter. Each equation of the complete system, that means, the equation of continuity, the ...
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The concept of a variational solution to the full Navier-Stokes-Fourier system is introduced in this chapter. Each equation of the complete system, that means, the equation of continuity, the momentum equation, and the energy equation, is treated separately. The basic facts of the theory of renormalized solutions of the continuity equation are reviewed. Moreover, the renormalized solutions of the thermal energy are introduced as a suitable tool to deal with possible concentrations of temperature.Less
The concept of a variational solution to the full Navier-Stokes-Fourier system is introduced in this chapter. Each equation of the complete system, that means, the equation of continuity, the momentum equation, and the energy equation, is treated separately. The basic facts of the theory of renormalized solutions of the continuity equation are reviewed. Moreover, the renormalized solutions of the thermal energy are introduced as a suitable tool to deal with possible concentrations of temperature.
Eduard Feireisl
- Published in print:
- 2003
- Published Online:
- September 2007
- ISBN:
- 9780198528388
- eISBN:
- 9780191713590
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198528388.003.0006
- Subject:
- Mathematics, Applied Mathematics
Given the rather poor a priori estimates available, the methods of weak convergence play a decisive role in the mathematical theory to be developed in this book. Both ‘classical’ problems of this ...
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Given the rather poor a priori estimates available, the methods of weak convergence play a decisive role in the mathematical theory to be developed in this book. Both ‘classical’ problems of this approach — the presence of oscillations and concentrations in sequences of approximate solutions — are present. The well-known results of the theory of compensated compactness are used in order to cope with possible density oscillations. More specifically, the fundamental properties of the effective viscous pressure discovered by P.-L. Lions are discussed together with an alternative proof of ‘continuity’ of this quantity via the famous div-curl lemma. Next, the concept of oscillation defect measure is introduced, and its relation to the propagation of oscillations and the renormalized continuity equation is established. Furthermore, the whole machinery is applied to the problem of propagation of density oscillations in a sequence of solutions, and it is shown that the oscillations decay in time at a uniform rate independent of the choice of initial data provided the pressure is a monotone function of the density. The weak sequential stability (compactness) of the set of weak solutions is established for optimal values of the ‘adiabatic’ exponent. In particular, the physically interesting case of the monoatomic gas in the isentropic regime in three space dimensions can be treated — a problem left open in current theory. Possible concentrations in the temperature are treated via the method of renormalization (rescaling). A ‘renormalized’ formulation of the thermal energy equation is supplemented with the concept of a renormalized limit, usefulness of which being demonstrated on the problem of weak sequential stability and the study of possible concentrations of the temperature in the thermal energy equation.Less
Given the rather poor a priori estimates available, the methods of weak convergence play a decisive role in the mathematical theory to be developed in this book. Both ‘classical’ problems of this approach — the presence of oscillations and concentrations in sequences of approximate solutions — are present. The well-known results of the theory of compensated compactness are used in order to cope with possible density oscillations. More specifically, the fundamental properties of the effective viscous pressure discovered by P.-L. Lions are discussed together with an alternative proof of ‘continuity’ of this quantity via the famous div-curl lemma. Next, the concept of oscillation defect measure is introduced, and its relation to the propagation of oscillations and the renormalized continuity equation is established. Furthermore, the whole machinery is applied to the problem of propagation of density oscillations in a sequence of solutions, and it is shown that the oscillations decay in time at a uniform rate independent of the choice of initial data provided the pressure is a monotone function of the density. The weak sequential stability (compactness) of the set of weak solutions is established for optimal values of the ‘adiabatic’ exponent. In particular, the physically interesting case of the monoatomic gas in the isentropic regime in three space dimensions can be treated — a problem left open in current theory. Possible concentrations in the temperature are treated via the method of renormalization (rescaling). A ‘renormalized’ formulation of the thermal energy equation is supplemented with the concept of a renormalized limit, usefulness of which being demonstrated on the problem of weak sequential stability and the study of possible concentrations of the temperature in the thermal energy equation.
Doreen Kimura
- Published in print:
- 1993
- Published Online:
- January 2008
- ISBN:
- 9780195054927
- eISBN:
- 9780199872268
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195054927.003.0005
- Subject:
- Psychology, Neuropsychology
This chapter examines the co-occurrence of speech and nonspeech oral-movement defects, and the relation between oral-movement control and manual-movement control. The repetition of single syllables ...
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This chapter examines the co-occurrence of speech and nonspeech oral-movement defects, and the relation between oral-movement control and manual-movement control. The repetition of single syllables and the reproduction of single oral movements correlate significantly and are critically dependent on the left anterior region. Left posterior systems apparently play a very minor role in controlling speech or nonspeech oral movements of this kind. However, the posterior region does take part in selecting oral movements when more than one must be produced. Within the posterior region, temporal and parietal systems make somewhat different contributions. The parietal lobe in many persons is critical for the selection of articulatory/motor acts irrespective of whether these involve speech or not. The temporal lobe appears to be critical for selection of speech at a word (rather than an articulatory) level and when damaged results in poor repetition of multisyllabic words or phrases.Less
This chapter examines the co-occurrence of speech and nonspeech oral-movement defects, and the relation between oral-movement control and manual-movement control. The repetition of single syllables and the reproduction of single oral movements correlate significantly and are critically dependent on the left anterior region. Left posterior systems apparently play a very minor role in controlling speech or nonspeech oral movements of this kind. However, the posterior region does take part in selecting oral movements when more than one must be produced. Within the posterior region, temporal and parietal systems make somewhat different contributions. The parietal lobe in many persons is critical for the selection of articulatory/motor acts irrespective of whether these involve speech or not. The temporal lobe appears to be critical for selection of speech at a word (rather than an articulatory) level and when damaged results in poor repetition of multisyllabic words or phrases.
Anne-Lise Christensen
- Published in print:
- 2009
- Published Online:
- February 2010
- ISBN:
- 9780195176704
- eISBN:
- 9780199864706
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195176704.003.0001
- Subject:
- Neuroscience, History of Neuroscience
In this context the first chapter concentrates on Luria's theories and his work in science, stressing individuality and variability. In his diagnostic methods two issues are emphasized: (1) the ...
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In this context the first chapter concentrates on Luria's theories and his work in science, stressing individuality and variability. In his diagnostic methods two issues are emphasized: (1) the concept of function, considered as complex functional systems, not localized, but distributed as networks across broader areas of the brain, and (2) the right technique for the careful analysis of these networks, since each local lesion of the cortex results in a very specific type of disturbance. It is suggested that the application of these principles to the examination of the brain injured patient will lead not only to a more precise and early diagnosis but at the same time provide the possibility for a careful planning of the most effective treatment procedure and planning of rehabilitation.Less
In this context the first chapter concentrates on Luria's theories and his work in science, stressing individuality and variability. In his diagnostic methods two issues are emphasized: (1) the concept of function, considered as complex functional systems, not localized, but distributed as networks across broader areas of the brain, and (2) the right technique for the careful analysis of these networks, since each local lesion of the cortex results in a very specific type of disturbance. It is suggested that the application of these principles to the examination of the brain injured patient will lead not only to a more precise and early diagnosis but at the same time provide the possibility for a careful planning of the most effective treatment procedure and planning of rehabilitation.
Richard Fumerton
- Published in print:
- 2010
- Published Online:
- September 2010
- ISBN:
- 9780199226078
- eISBN:
- 9780191594236
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199226078.003.0006
- Subject:
- Philosophy, Moral Philosophy, Metaphysics/Epistemology
This chapter discusses disagreements in philosophy. It acknowledges that learning of peer disagreement provides a reason against a philosophical belief one holds, but argues that one can discount ...
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This chapter discusses disagreements in philosophy. It acknowledges that learning of peer disagreement provides a reason against a philosophical belief one holds, but argues that one can discount this sort of reason against one's view on the grounds that most philosophers are unreliable on the sort of issue in question, a fact that makes it likely that the philosopher with whom one disagrees is also unreliable. However, this way of out the sceptical puzzle posed by disagreements leads to another problem, since the reliability of a philosopher making such an argument is also called into question.Less
This chapter discusses disagreements in philosophy. It acknowledges that learning of peer disagreement provides a reason against a philosophical belief one holds, but argues that one can discount this sort of reason against one's view on the grounds that most philosophers are unreliable on the sort of issue in question, a fact that makes it likely that the philosopher with whom one disagrees is also unreliable. However, this way of out the sceptical puzzle posed by disagreements leads to another problem, since the reliability of a philosopher making such an argument is also called into question.
Victor F. Petrenko and Robert W. Whitworth
- Published in print:
- 2002
- Published Online:
- February 2010
- ISBN:
- 9780198518945
- eISBN:
- 9780191707247
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198518945.003.0006
- Subject:
- Physics, Crystallography
Point defects are atomic or molecular sites that differ from the normal sites in the lattice. In ice these are not only the usual vacancies, interstitials, or impurity atoms but also the protonic ...
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Point defects are atomic or molecular sites that differ from the normal sites in the lattice. In ice these are not only the usual vacancies, interstitials, or impurity atoms but also the protonic point defects: H3O+ ions, OH- ions, and Bjerrum defects. The Bjerrum L-defect is a bond with no proton on it and the D-defect is a bond with two protons associated with it. This chapter starts with the theory of vacancies and interstitials and their role in molecular diffusion. With rapid drop in temperature these condense to form prismatic dislocation loops. Apart from their role in the electrical properties, the protonic point defects account for anelastic relaxation and effects arising from the exchange of H and D isotopes. The structure and mobility of these defects are important topics for theoretical modelling. The chapter concludes with nuclear magnetic resonance, muon spin resonance, chemical impurities, electronic defects, and photoconductivity.Less
Point defects are atomic or molecular sites that differ from the normal sites in the lattice. In ice these are not only the usual vacancies, interstitials, or impurity atoms but also the protonic point defects: H3O+ ions, OH- ions, and Bjerrum defects. The Bjerrum L-defect is a bond with no proton on it and the D-defect is a bond with two protons associated with it. This chapter starts with the theory of vacancies and interstitials and their role in molecular diffusion. With rapid drop in temperature these condense to form prismatic dislocation loops. Apart from their role in the electrical properties, the protonic point defects account for anelastic relaxation and effects arising from the exchange of H and D isotopes. The structure and mobility of these defects are important topics for theoretical modelling. The chapter concludes with nuclear magnetic resonance, muon spin resonance, chemical impurities, electronic defects, and photoconductivity.
ROBERT V. DODGE
- Published in print:
- 2012
- Published Online:
- May 2012
- ISBN:
- 9780199857203
- eISBN:
- 9780199932597
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199857203.003.0012
- Subject:
- Economics and Finance, Behavioural Economics
This chapter focuses on the best-known game in game theory, the prisoner's dilemma. It begins with the development of the game at the RAND Corporation. Classical economics is based on the idea that ...
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This chapter focuses on the best-known game in game theory, the prisoner's dilemma. It begins with the development of the game at the RAND Corporation. Classical economics is based on the idea that the greatest good is achieved by pursuing individual self-interest and this simple two-by-two game demonstrates that the “rational” choice could be to behave in a seemingly non-rational way; that the superior outcome could be achieved through cooperation. The standard story developed by Albert Tucker that gave the game the name “prisoner's dilemma” is described. The basic prisoner's dilemma matrix is presented and the ranking of utility payoffs is listed along with the names for the payoffs used by Sugden and many others: the “trust” payoff, the “nasty” payoff, the “sucker” payoff. Examples of the prisoner's dilemmas from everyday life and international relations are given, as is Schelling's struggle against the prisoner's dilemma of the Cold War arms race, where he worked to achieve gains in arms control. The final part of the chapter mentions references to the prisoner's dilemma in recent journalism from around the world, showing its wide acceptance as a term for situations in which individual self interest harms group benefit.Less
This chapter focuses on the best-known game in game theory, the prisoner's dilemma. It begins with the development of the game at the RAND Corporation. Classical economics is based on the idea that the greatest good is achieved by pursuing individual self-interest and this simple two-by-two game demonstrates that the “rational” choice could be to behave in a seemingly non-rational way; that the superior outcome could be achieved through cooperation. The standard story developed by Albert Tucker that gave the game the name “prisoner's dilemma” is described. The basic prisoner's dilemma matrix is presented and the ranking of utility payoffs is listed along with the names for the payoffs used by Sugden and many others: the “trust” payoff, the “nasty” payoff, the “sucker” payoff. Examples of the prisoner's dilemmas from everyday life and international relations are given, as is Schelling's struggle against the prisoner's dilemma of the Cold War arms race, where he worked to achieve gains in arms control. The final part of the chapter mentions references to the prisoner's dilemma in recent journalism from around the world, showing its wide acceptance as a term for situations in which individual self interest harms group benefit.
Sidney Yip
- Published in print:
- 2009
- Published Online:
- February 2010
- ISBN:
- 9780199233854
- eISBN:
- 9780191715532
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199233854.003.0014
- Subject:
- Mathematics, Applied Mathematics
Modeling and simulation across different length and time scales enables atomic-level understanding of materials properties and behavior which manifest at the meso- and macro-scales. Case studies of ...
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Modeling and simulation across different length and time scales enables atomic-level understanding of materials properties and behavior which manifest at the meso- and macro-scales. Case studies of theoretical strength of crystals and defect nucleation and mobility illustrate the recent progress on studying unit processes. A future challenge lies in probing complex functional behavior of real materials.Less
Modeling and simulation across different length and time scales enables atomic-level understanding of materials properties and behavior which manifest at the meso- and macro-scales. Case studies of theoretical strength of crystals and defect nucleation and mobility illustrate the recent progress on studying unit processes. A future challenge lies in probing complex functional behavior of real materials.
Harry Schachter
- Published in print:
- 2005
- Published Online:
- September 2009
- ISBN:
- 9780198525387
- eISBN:
- 9780191723872
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198525387.003.0007
- Subject:
- Neuroscience, Molecular and Cellular Systems
This chapter discusses recent knowledge on gene knockout mice with deficient glycosyltransferases. It covers a large number of gene inactivation of glycosyltransferases, and should be valuable for ...
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This chapter discusses recent knowledge on gene knockout mice with deficient glycosyltransferases. It covers a large number of gene inactivation of glycosyltransferases, and should be valuable for anyone who want to look at the effect of one particular knockout. The pathological consequences of human patients with glycosylation defect are also described.Less
This chapter discusses recent knowledge on gene knockout mice with deficient glycosyltransferases. It covers a large number of gene inactivation of glycosyltransferases, and should be valuable for anyone who want to look at the effect of one particular knockout. The pathological consequences of human patients with glycosylation defect are also described.
Hillary R. Rodman
- Published in print:
- 2006
- Published Online:
- September 2009
- ISBN:
- 9780198528999
- eISBN:
- 9780191723926
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198528999.003.0005
- Subject:
- Neuroscience, Disorders of the Nervous System
This chapter describes the behavioral deficits observed following lesions of the primary visual cortex in both mature and infant macaque monkeys. Overall, the consequences of such lesions are far ...
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This chapter describes the behavioral deficits observed following lesions of the primary visual cortex in both mature and infant macaque monkeys. Overall, the consequences of such lesions are far more severe in adulthood than during development. The chapter also presents anatomical evidence that alterations to the thalamocortical pathways may explain the greater behavioral abilities identified following visual cortex lesions incurred during development, but not maturity.Less
This chapter describes the behavioral deficits observed following lesions of the primary visual cortex in both mature and infant macaque monkeys. Overall, the consequences of such lesions are far more severe in adulthood than during development. The chapter also presents anatomical evidence that alterations to the thalamocortical pathways may explain the greater behavioral abilities identified following visual cortex lesions incurred during development, but not maturity.
Frances M. Platt and Steven U. Walkley
- Published in print:
- 2004
- Published Online:
- September 2009
- ISBN:
- 9780198508786
- eISBN:
- 9780191723803
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198508786.003.0002
- Subject:
- Neuroscience, Disorders of the Nervous System
This chapter begins with a discussion of traditional classification of lysosomal storage diseases. It then discusses the classification of lysosomal diseases based on molecular defect. These include ...
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This chapter begins with a discussion of traditional classification of lysosomal storage diseases. It then discusses the classification of lysosomal diseases based on molecular defect. These include a substrate-based classification scheme and a scheme that is based on a molecular mechanism leading to storage. Both have different roles to play in aiding our understanding of these disorders and their biochemical and molecular relationships. However, it is certainly the case that a mechanism-based understanding is the only route to the rational development of therapies. It also gives a different perspective on the disease process, emphasizing the complexities of the underlying pathogenic cascades.Less
This chapter begins with a discussion of traditional classification of lysosomal storage diseases. It then discusses the classification of lysosomal diseases based on molecular defect. These include a substrate-based classification scheme and a scheme that is based on a molecular mechanism leading to storage. Both have different roles to play in aiding our understanding of these disorders and their biochemical and molecular relationships. However, it is certainly the case that a mechanism-based understanding is the only route to the rational development of therapies. It also gives a different perspective on the disease process, emphasizing the complexities of the underlying pathogenic cascades.
JACK ROSENBLUTH
- Published in print:
- 1995
- Published Online:
- May 2009
- ISBN:
- 9780195082937
- eISBN:
- 9780199865802
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195082937.003.0021
- Subject:
- Neuroscience, Disorders of the Nervous System
Glial cells exert a reciprocal influence on axons, affecting both structure and function in ways that have important physiological consequences. The functional abnormalities associated with myelin ...
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Glial cells exert a reciprocal influence on axons, affecting both structure and function in ways that have important physiological consequences. The functional abnormalities associated with myelin pathology arise not from myelin defects alone, but from a combination of the myelin damage per se and secondary alterations in the demyelinated or dysmyelinated axons, involving changes in the structural differentiation of the axon and in the complement and distribution of axolemmal ion channels. This chapter reviews this subject using as prototypical examples studies previously carried out on congenitally myelin-deficient animals, and on acutely and chronically injured myelinated nerve fibers.Less
Glial cells exert a reciprocal influence on axons, affecting both structure and function in ways that have important physiological consequences. The functional abnormalities associated with myelin pathology arise not from myelin defects alone, but from a combination of the myelin damage per se and secondary alterations in the demyelinated or dysmyelinated axons, involving changes in the structural differentiation of the axon and in the complement and distribution of axolemmal ion channels. This chapter reviews this subject using as prototypical examples studies previously carried out on congenitally myelin-deficient animals, and on acutely and chronically injured myelinated nerve fibers.
Victor F. Petrenko and Robert W. Whitworth
- Published in print:
- 2002
- Published Online:
- February 2010
- ISBN:
- 9780198518945
- eISBN:
- 9780191707247
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198518945.003.0004
- Subject:
- Physics, Crystallography
Ice has a large dielectric permittivity arising from the reorientation of molecular dipoles in an electric field. This reorientation occurs by the motion of protonic point defects — H3O+ and OH- ions ...
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Ice has a large dielectric permittivity arising from the reorientation of molecular dipoles in an electric field. This reorientation occurs by the motion of protonic point defects — H3O+ and OH- ions and Bjerrum L- and D-defects. The permittivity exhibits an almost ideal Debye relaxation and there is also a d.c. conductivity that arises from the migration of protons through the lattice. This chapter first treats the overall process of relaxation, then the theory of the thermodynamic equilibrium permittivity, and after that the interpretation of the dielectric and conduction properties in terms of protonic point defects according to the Jaccard theory. It then considers the effect of electrodes, and the various times constants involved. It concludes with a summary of the essential equations describing the electrical properties of ice.Less
Ice has a large dielectric permittivity arising from the reorientation of molecular dipoles in an electric field. This reorientation occurs by the motion of protonic point defects — H3O+ and OH- ions and Bjerrum L- and D-defects. The permittivity exhibits an almost ideal Debye relaxation and there is also a d.c. conductivity that arises from the migration of protons through the lattice. This chapter first treats the overall process of relaxation, then the theory of the thermodynamic equilibrium permittivity, and after that the interpretation of the dielectric and conduction properties in terms of protonic point defects according to the Jaccard theory. It then considers the effect of electrodes, and the various times constants involved. It concludes with a summary of the essential equations describing the electrical properties of ice.
Nasr M. Ghoniem and Daniel D. Walgraef
- Published in print:
- 2008
- Published Online:
- May 2008
- ISBN:
- 9780199298686
- eISBN:
- 9780191720222
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199298686.003.0003
- Subject:
- Physics, Condensed Matter Physics / Materials
Defects play a critical role in many material phenomena, and their relationship to instabilities and pattern formation is well-established. This chapter presents a brief description of the main types ...
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Defects play a critical role in many material phenomena, and their relationship to instabilities and pattern formation is well-established. This chapter presents a brief description of the main types of crystal defects, describing their geometry and main characteristics. It then focuses on determining their elastic field and interaction forces.Less
Defects play a critical role in many material phenomena, and their relationship to instabilities and pattern formation is well-established. This chapter presents a brief description of the main types of crystal defects, describing their geometry and main characteristics. It then focuses on determining their elastic field and interaction forces.
Erich H. Kisi and Christopher J. Howard
- Published in print:
- 2008
- Published Online:
- January 2009
- ISBN:
- 9780198515944
- eISBN:
- 9780191705663
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198515944.003.0009
- Subject:
- Physics, Condensed Matter Physics / Materials
This chapter describes how diffraction peaks can be broadened, and sometimes their intensities altered, by microstructural effects. Much of the theory was developed for X-rays, but is also applicable ...
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This chapter describes how diffraction peaks can be broadened, and sometimes their intensities altered, by microstructural effects. Much of the theory was developed for X-rays, but is also applicable in the neutron case. Peaks are broadened due to small crystallite size, or the presence of microstrains, or both. The analysis may involve deconvolution, individual peak fitting, whole pattern fitting, and the Scherrer equation. Methods for handling anisotropic broadening are presented. The Williamson-Hall plot is shown to be useful when size and strain broadening both are present. The effects on peak shapes of chemical and physical gradients are considered in detail: strain gradients for example lead to domain wall scattering. The theory of broadening due to dislocations is presented, and illustrated by application to LaNi5. The effects of planar defects, such as stacking faults and twin boundaries, are also considered. Finally, the effect on intensities of texture (preferred orientation) is discussed.Less
This chapter describes how diffraction peaks can be broadened, and sometimes their intensities altered, by microstructural effects. Much of the theory was developed for X-rays, but is also applicable in the neutron case. Peaks are broadened due to small crystallite size, or the presence of microstrains, or both. The analysis may involve deconvolution, individual peak fitting, whole pattern fitting, and the Scherrer equation. Methods for handling anisotropic broadening are presented. The Williamson-Hall plot is shown to be useful when size and strain broadening both are present. The effects on peak shapes of chemical and physical gradients are considered in detail: strain gradients for example lead to domain wall scattering. The theory of broadening due to dislocations is presented, and illustrated by application to LaNi5. The effects of planar defects, such as stacking faults and twin boundaries, are also considered. Finally, the effect on intensities of texture (preferred orientation) is discussed.
Ezra Susser, Sharon Schwartz, Alfredo Morabia, and Evelyn J. Bromet
- Published in print:
- 2006
- Published Online:
- September 2009
- ISBN:
- 9780195101812
- eISBN:
- 9780199864096
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195101812.003.06
- Subject:
- Public Health and Epidemiology, Public Health, Epidemiology
This chapter describes different risk factor study designs. Study designs can be viewed as techniques for organizing observations in ways that can reveal the causes of disease. The risk factor study ...
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This chapter describes different risk factor study designs. Study designs can be viewed as techniques for organizing observations in ways that can reveal the causes of disease. The risk factor study designs attempt to do this by mimicking the counterfactual, which is the true test of causal effects. When the mimicry is successful, studies isolate the effects of the exposure on the disease. In regard to this mimicry, the randomized controlled trial is the simplest and most direct, but practical for only a small number of exposures. The cohort study is much more widely applicable, but selection into exposure is not random. The case-control study is more complex and indirect but often the most useful. Although the specific techniques differ among designs, the underlying strategy is the same—the examination of fully comparable groups of exposed and unexposed individuals to isolate the effects of specific risk factors. The chapter illustrates how each study was used to investigate the causal effect of low prenatal folate intake on neural tube defects (NTDs).Less
This chapter describes different risk factor study designs. Study designs can be viewed as techniques for organizing observations in ways that can reveal the causes of disease. The risk factor study designs attempt to do this by mimicking the counterfactual, which is the true test of causal effects. When the mimicry is successful, studies isolate the effects of the exposure on the disease. In regard to this mimicry, the randomized controlled trial is the simplest and most direct, but practical for only a small number of exposures. The cohort study is much more widely applicable, but selection into exposure is not random. The case-control study is more complex and indirect but often the most useful. Although the specific techniques differ among designs, the underlying strategy is the same—the examination of fully comparable groups of exposed and unexposed individuals to isolate the effects of specific risk factors. The chapter illustrates how each study was used to investigate the causal effect of low prenatal folate intake on neural tube defects (NTDs).
