Juan Luis Vázquez
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780199202973
- eISBN:
- 9780191707919
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199202973.001.0001
- Subject:
- Mathematics, Applied Mathematics
This book is concerned with the quantitative aspects of the theory of nonlinear diffusion equations; equations which can be seen as nonlinear variations of the classical heat equation. They appear as ...
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This book is concerned with the quantitative aspects of the theory of nonlinear diffusion equations; equations which can be seen as nonlinear variations of the classical heat equation. They appear as mathematical models in different branches of physics, chemistry, biology, and engineering, and are also relevant in differential geometry and relativistic physics. Much of the modern theory of such equations is based on estimates and functional analysis. Concentrating on a class of equations with nonlinearities of power type that lead to degenerate or singular parabolicity (equations of porous medium type), the aim of this book is to obtain sharp a priori estimates and decay rates for general classes of solutions in terms of estimates of particular problems. These estimates are the building blocks in understanding the qualitative theory, and the decay rates pave the way to the fine study of asymptotics. Many technically relevant questions are presented and analyzed in detail. A systematic picture of the most relevant phenomena is obtained for the equations under study, including time decay, smoothing, extinction in finite time, and delayed regularity.Less
This book is concerned with the quantitative aspects of the theory of nonlinear diffusion equations; equations which can be seen as nonlinear variations of the classical heat equation. They appear as mathematical models in different branches of physics, chemistry, biology, and engineering, and are also relevant in differential geometry and relativistic physics. Much of the modern theory of such equations is based on estimates and functional analysis. Concentrating on a class of equations with nonlinearities of power type that lead to degenerate or singular parabolicity (equations of porous medium type), the aim of this book is to obtain sharp a priori estimates and decay rates for general classes of solutions in terms of estimates of particular problems. These estimates are the building blocks in understanding the qualitative theory, and the decay rates pave the way to the fine study of asymptotics. Many technically relevant questions are presented and analyzed in detail. A systematic picture of the most relevant phenomena is obtained for the equations under study, including time decay, smoothing, extinction in finite time, and delayed regularity.
David Benatar
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780199296422
- eISBN:
- 9780191712005
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199296422.001.0001
- Subject:
- Philosophy, Moral Philosophy
This book argues for a number of related, highly provocative views: (i) coming into existence is always a serious harm; (ii) procreation is always wrong; (iii) it is wrong not to abort foetuses at ...
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This book argues for a number of related, highly provocative views: (i) coming into existence is always a serious harm; (ii) procreation is always wrong; (iii) it is wrong not to abort foetuses at the earlier stages of gestation; and (iv) it would be better if, as a result of there being no new people, humanity became extinct. Although these conclusions are antagonistic to common and deeply held intuitions, the book argues that these intuitions are unreliable and thus cannot be used to refute it's grim-sounding conclusions.Less
This book argues for a number of related, highly provocative views: (i) coming into existence is always a serious harm; (ii) procreation is always wrong; (iii) it is wrong not to abort foetuses at the earlier stages of gestation; and (iv) it would be better if, as a result of there being no new people, humanity became extinct. Although these conclusions are antagonistic to common and deeply held intuitions, the book argues that these intuitions are unreliable and thus cannot be used to refute it's grim-sounding conclusions.
Jacob Höglund
- Published in print:
- 2009
- Published Online:
- May 2009
- ISBN:
- 9780199214211
- eISBN:
- 9780191706660
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199214211.001.0001
- Subject:
- Biology, Biodiversity / Conservation Biology, Evolutionary Biology / Genetics
Conservation genetics focuses on understanding the role and requirement of genetic variation for population persistence. However, considerable debate now surrounds the role of genetic factors (as ...
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Conservation genetics focuses on understanding the role and requirement of genetic variation for population persistence. However, considerable debate now surrounds the role of genetic factors (as opposed to non-genetic factors such as habitat destruction, etc.) in population extinction, and a synthesis is now timely. Can extinction be explained by habitat destruction alone or is lack of genetic variation a part of the explanation? The book reviews the arguments for a role of genetics in the present biodiversity crisis. It describes the methods used to study genetic variation in endangered species and examines the influence of genetic variation in the extinction of species. To date, conservation genetics has predominantly utilized neutral genetic markers, e.g., microsatellites. However, with the recent advances in molecular genetics and genomics it will soon be possible to study ‘direct gene action’, following the fate of genetic variation at the level of DNA, through expression, to proteins in order to determine how such phenotypes fare in populations of free living organisms. This book explores these exciting avenues of future research potential, integrating ecological quantitative genetics with the new genome science. It is now more important than ever that we ask relevant questions about the evolutionary fate of endangered populations throughout the globe and incorporate our knowledge of evolutionary processes and the distribution of genetic diversity into effective conservation planning and action.Less
Conservation genetics focuses on understanding the role and requirement of genetic variation for population persistence. However, considerable debate now surrounds the role of genetic factors (as opposed to non-genetic factors such as habitat destruction, etc.) in population extinction, and a synthesis is now timely. Can extinction be explained by habitat destruction alone or is lack of genetic variation a part of the explanation? The book reviews the arguments for a role of genetics in the present biodiversity crisis. It describes the methods used to study genetic variation in endangered species and examines the influence of genetic variation in the extinction of species. To date, conservation genetics has predominantly utilized neutral genetic markers, e.g., microsatellites. However, with the recent advances in molecular genetics and genomics it will soon be possible to study ‘direct gene action’, following the fate of genetic variation at the level of DNA, through expression, to proteins in order to determine how such phenotypes fare in populations of free living organisms. This book explores these exciting avenues of future research potential, integrating ecological quantitative genetics with the new genome science. It is now more important than ever that we ask relevant questions about the evolutionary fate of endangered populations throughout the globe and incorporate our knowledge of evolutionary processes and the distribution of genetic diversity into effective conservation planning and action.
Wallace Matson
- Published in print:
- 2011
- Published Online:
- January 2012
- ISBN:
- 9780199812691
- eISBN:
- 9780199919420
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199812691.003.0025
- Subject:
- Philosophy, History of Philosophy
Humankind, still adapted to the hunter-gatherer life, has moved with astonishing speed into an utterly different lifestyle, offering numerous advantages but also multiplying dangers: civilization. ...
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Humankind, still adapted to the hunter-gatherer life, has moved with astonishing speed into an utterly different lifestyle, offering numerous advantages but also multiplying dangers: civilization. The Milesians added science, which translated into advanced technologies. Is this progress? Certainly, in a way. But on the whole, and sub specie aeternitatis, a good thing for animals like us? Alas, probably not. Having attained a glimpse of The Grand Unified Theory of Everything is the highest achievement of the human spirit, but …Less
Humankind, still adapted to the hunter-gatherer life, has moved with astonishing speed into an utterly different lifestyle, offering numerous advantages but also multiplying dangers: civilization. The Milesians added science, which translated into advanced technologies. Is this progress? Certainly, in a way. But on the whole, and sub specie aeternitatis, a good thing for animals like us? Alas, probably not. Having attained a glimpse of The Grand Unified Theory of Everything is the highest achievement of the human spirit, but …
Russell Lande, Steinar Engen, and Bernt-Erik Saether
- Published in print:
- 2003
- Published Online:
- April 2010
- ISBN:
- 9780198525257
- eISBN:
- 9780191584930
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198525257.001.0001
- Subject:
- Biology, Ecology
All populations fluctuate stochastically, creating a risk of extinction that does not exist in deterministic models, with fundamental consequences for both pure and applied ecology. This book ...
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All populations fluctuate stochastically, creating a risk of extinction that does not exist in deterministic models, with fundamental consequences for both pure and applied ecology. This book provides an introduction to stochastic population dynamics, combining classical background material with a variety of modern approaches, including previously unpublished results by the authors, illustrated with examples from bird and mammal populations, and insect communities. Demographic and environmental stochasticity are introduced with statistical methods for estimating them from field data. The long-run growth rate of a population is explained and extended to include age structure with both demographic and environmental stochasticity. Diffusion approximations facilitate the analysis of extinction dynamics and the duration of the final decline. Methods are developed for estimating delayed density dependence from population time series using life history data. Metapopulation viability and the spatial scale of population fluctuations and extinction risk are analyzed. Stochastic dynamics and statistical uncertainty in population parameters are incorporated in Population Viability Analysis and strategies for sustainable harvesting. Statistics of species diversity measures and species abundance distributions are described, with implications for rapid assessments of biodiversity, and methods are developed for partitioning species diversity into additive components. Analysis of the stochastic dynamics of a tropical butterfly community in space and time indicates that most of the variance in the species abundance distribution is due to ecological heterogeneity among species, so that real communities are far from neutral.Less
All populations fluctuate stochastically, creating a risk of extinction that does not exist in deterministic models, with fundamental consequences for both pure and applied ecology. This book provides an introduction to stochastic population dynamics, combining classical background material with a variety of modern approaches, including previously unpublished results by the authors, illustrated with examples from bird and mammal populations, and insect communities. Demographic and environmental stochasticity are introduced with statistical methods for estimating them from field data. The long-run growth rate of a population is explained and extended to include age structure with both demographic and environmental stochasticity. Diffusion approximations facilitate the analysis of extinction dynamics and the duration of the final decline. Methods are developed for estimating delayed density dependence from population time series using life history data. Metapopulation viability and the spatial scale of population fluctuations and extinction risk are analyzed. Stochastic dynamics and statistical uncertainty in population parameters are incorporated in Population Viability Analysis and strategies for sustainable harvesting. Statistics of species diversity measures and species abundance distributions are described, with implications for rapid assessments of biodiversity, and methods are developed for partitioning species diversity into additive components. Analysis of the stochastic dynamics of a tropical butterfly community in space and time indicates that most of the variance in the species abundance distribution is due to ecological heterogeneity among species, so that real communities are far from neutral.
K. David Harrison
- Published in print:
- 2007
- Published Online:
- January 2010
- ISBN:
- 9780195181920
- eISBN:
- 9780199870622
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195181920.001.0001
- Subject:
- Linguistics, Historical Linguistics
It is commonly agreed by linguists and anthropologists that the majority of languages spoken now around the globe will likely disappear within our lifetime. The phenomenon known as language death has ...
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It is commonly agreed by linguists and anthropologists that the majority of languages spoken now around the globe will likely disappear within our lifetime. The phenomenon known as language death has started to accelerate as the world has grown smaller. This extinction of languages, and the knowledge therein, has no parallel in human history. This book focuses on the essential questions: What is lost when a language dies?; What forms of knowledge are embedded in a language's structure and vocabulary?; And how harmful is it to humanity that such knowledge is lost forever? The book spans the globe from Siberia to North America to the Himalayas and elsewhere, to look at the human knowledge that is slowly being lost as the languages which express it fade from sight. It uses fascinating anecdotes and portraits of some of these languages' last remaining speakers, in order to demonstrate that this knowledge about ourselves and the world is inherently precious, and once gone, will be lost forever. This knowledge is not only our cultural heritage (oral histories, poetry, stories, etc.) but very useful knowledge about plants, animals, the seasons, and other aspects of the natural world—not to mention our understanding of the capacities of the human mind.Less
It is commonly agreed by linguists and anthropologists that the majority of languages spoken now around the globe will likely disappear within our lifetime. The phenomenon known as language death has started to accelerate as the world has grown smaller. This extinction of languages, and the knowledge therein, has no parallel in human history. This book focuses on the essential questions: What is lost when a language dies?; What forms of knowledge are embedded in a language's structure and vocabulary?; And how harmful is it to humanity that such knowledge is lost forever? The book spans the globe from Siberia to North America to the Himalayas and elsewhere, to look at the human knowledge that is slowly being lost as the languages which express it fade from sight. It uses fascinating anecdotes and portraits of some of these languages' last remaining speakers, in order to demonstrate that this knowledge about ourselves and the world is inherently precious, and once gone, will be lost forever. This knowledge is not only our cultural heritage (oral histories, poetry, stories, etc.) but very useful knowledge about plants, animals, the seasons, and other aspects of the natural world—not to mention our understanding of the capacities of the human mind.
Stuart L. Pimm and Clinton N. Jenkins
- Published in print:
- 2010
- Published Online:
- February 2010
- ISBN:
- 9780199554232
- eISBN:
- 9780191720666
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199554232.003.0011
- Subject:
- Biology, Ecology, Biodiversity / Conservation Biology
Stuart L. Pimm and Clinton N. Jenkins explore why extinctions are the critical issue for conservation science. Extinctions are irreversible, unlike many other environmental threats that we can ...
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Stuart L. Pimm and Clinton N. Jenkins explore why extinctions are the critical issue for conservation science. Extinctions are irreversible, unlike many other environmental threats that we can reverse. Current and recent rates of extinction are 100 times faster than the background rate, while future rates may be 1000 times faster. Species most likely to face extinction are rare; rare either because they have very small geographic ranges or have a low population density with a larger range. Small‐ranged terrestrial vertebrate species tend to be concentrated in a few areas that often do not hold the greatest number of species. Similar patterns apply to plants and many marine groups. Extinctions occur most often when human impacts collide with the places having many rare species. While habitat loss is the leading cause of extinctions, global warming is expected to cause extinctions that are additive to those caused by habitat loss.Less
Stuart L. Pimm and Clinton N. Jenkins explore why extinctions are the critical issue for conservation science. Extinctions are irreversible, unlike many other environmental threats that we can reverse. Current and recent rates of extinction are 100 times faster than the background rate, while future rates may be 1000 times faster. Species most likely to face extinction are rare; rare either because they have very small geographic ranges or have a low population density with a larger range. Small‐ranged terrestrial vertebrate species tend to be concentrated in a few areas that often do not hold the greatest number of species. Similar patterns apply to plants and many marine groups. Extinctions occur most often when human impacts collide with the places having many rare species. While habitat loss is the leading cause of extinctions, global warming is expected to cause extinctions that are additive to those caused by habitat loss.
Marian Stamp Dawkins
- Published in print:
- 2007
- Published Online:
- January 2008
- ISBN:
- 9780198569350
- eISBN:
- 9780191717512
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198569350.003.0003
- Subject:
- Biology, Animal Biology
Sometimes single observations, such as the sighting of an animal thought to be extinct, or a chimpanzee making tools, are enough to change forever the way people think about the world. This chapter ...
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Sometimes single observations, such as the sighting of an animal thought to be extinct, or a chimpanzee making tools, are enough to change forever the way people think about the world. This chapter explores the situations when single observations are enough to destroy a hypothesis and the situations in which they are not. By emphasizing the power of the single unexpected or quantitative observation, the chapter paradoxically paves the way for an understanding of why, in most situations, repeated observations with large sample sizes are needed.Less
Sometimes single observations, such as the sighting of an animal thought to be extinct, or a chimpanzee making tools, are enough to change forever the way people think about the world. This chapter explores the situations when single observations are enough to destroy a hypothesis and the situations in which they are not. By emphasizing the power of the single unexpected or quantitative observation, the chapter paradoxically paves the way for an understanding of why, in most situations, repeated observations with large sample sizes are needed.
Richard Kraut
- Published in print:
- 2012
- Published Online:
- January 2012
- ISBN:
- 9780199844463
- eISBN:
- 9780199919550
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199844463.003.0027
- Subject:
- Philosophy, Moral Philosophy
At some time in the future, the human species will come to an end. The laws that govern the matter of our universe make this inevitable, but it is an event that may occur far sooner than need be. ...
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At some time in the future, the human species will come to an end. The laws that govern the matter of our universe make this inevitable, but it is an event that may occur far sooner than need be. This is a catastrophe that even we or our children may see looming for those who are alive several generations later. What reason would there be, in those circumstances, to take preventive action? Do earlier generations have reason to thwart a doomsday that will occur not to themselves, nor to any children or grandchildren they have, but to still more distant generations? This chapter argues that the things that are good for human beings are very great goods for those human beings, in comparison with the benefits that other living things possess. We should want others to have those goods, and the strength of our desire should be commensurate with the magnitude of those goods. We should not care just about the generation to which we belong.Less
At some time in the future, the human species will come to an end. The laws that govern the matter of our universe make this inevitable, but it is an event that may occur far sooner than need be. This is a catastrophe that even we or our children may see looming for those who are alive several generations later. What reason would there be, in those circumstances, to take preventive action? Do earlier generations have reason to thwart a doomsday that will occur not to themselves, nor to any children or grandchildren they have, but to still more distant generations? This chapter argues that the things that are good for human beings are very great goods for those human beings, in comparison with the benefits that other living things possess. We should want others to have those goods, and the strength of our desire should be commensurate with the magnitude of those goods. We should not care just about the generation to which we belong.
Daniel Oro
- Published in print:
- 2020
- Published Online:
- May 2020
- ISBN:
- 9780198849834
- eISBN:
- 9780191884368
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198849834.001.0001
- Subject:
- Biology, Ecology, Animal Biology
In social animals, perturbations may trigger specific behavioural responses with consequences for dispersal and complex population dynamics. Perturbations raise the need for information gathering in ...
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In social animals, perturbations may trigger specific behavioural responses with consequences for dispersal and complex population dynamics. Perturbations raise the need for information gathering in order to reduce uncertainty and increase resilience. Updated information is then shared within the group and social behaviours emerge as a self-organized process. This social information factoralizes with the size of the group, and it is finally used for making crucial decisions about, for instance, when to leave the patch and where to go. Indeed, evolution has favoured philopatry over dispersal, and this trade-off is challenged by perturbations. When perturbations accumulate over time, they may decrease the suitability of the patch and erode the philopatric state until crossing a tipping point, beyond which most individuals decide to disperse to better areas. Initially, the decision to disperse is led by a few individuals, and this decision is copied by the rest of the group in an autocatalytic way. This feedback process of social copying is termed runaway dispersal. Furthermore, social copying enhances the evolution of cultural and technological innovation, which may cause additional nonlinearities for population dynamics. Social information gathering and social copying have also occurred in human evolution, especially after perturbations such as climate extremes and warfare. In summary, social feedback processes cause nonlinear population dynamics including hysteresis and critical transitions (from philopatry to patch collapses and invasions), which emerge from the collective behaviour of large ensembles of individuals.Less
In social animals, perturbations may trigger specific behavioural responses with consequences for dispersal and complex population dynamics. Perturbations raise the need for information gathering in order to reduce uncertainty and increase resilience. Updated information is then shared within the group and social behaviours emerge as a self-organized process. This social information factoralizes with the size of the group, and it is finally used for making crucial decisions about, for instance, when to leave the patch and where to go. Indeed, evolution has favoured philopatry over dispersal, and this trade-off is challenged by perturbations. When perturbations accumulate over time, they may decrease the suitability of the patch and erode the philopatric state until crossing a tipping point, beyond which most individuals decide to disperse to better areas. Initially, the decision to disperse is led by a few individuals, and this decision is copied by the rest of the group in an autocatalytic way. This feedback process of social copying is termed runaway dispersal. Furthermore, social copying enhances the evolution of cultural and technological innovation, which may cause additional nonlinearities for population dynamics. Social information gathering and social copying have also occurred in human evolution, especially after perturbations such as climate extremes and warfare. In summary, social feedback processes cause nonlinear population dynamics including hysteresis and critical transitions (from philopatry to patch collapses and invasions), which emerge from the collective behaviour of large ensembles of individuals.
Juan Luis Vázquez
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780199202973
- eISBN:
- 9780191707919
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199202973.003.0010
- Subject:
- Mathematics, Applied Mathematics
This chapter addresses the question of extending the theory and estimates of the FDE to cover the singular range m ≤ 0, that has only been partially considered in previous chapters. This completes ...
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This chapter addresses the question of extending the theory and estimates of the FDE to cover the singular range m ≤ 0, that has only been partially considered in previous chapters. This completes the scope of the investigation about decay, smoothing effects, and best constants. But the range offers the possibility of learning about a novel and quite interesting dynamical issue: instantaneous extinction, which is tied to boundary layers at the initial time. The second part of the chapter discusses the question of local estimates improving on the results of previous sections. Finally an open problem is presented.Less
This chapter addresses the question of extending the theory and estimates of the FDE to cover the singular range m ≤ 0, that has only been partially considered in previous chapters. This completes the scope of the investigation about decay, smoothing effects, and best constants. But the range offers the possibility of learning about a novel and quite interesting dynamical issue: instantaneous extinction, which is tied to boundary layers at the initial time. The second part of the chapter discusses the question of local estimates improving on the results of previous sections. Finally an open problem is presented.
Juan Luis Vázquez
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780199202973
- eISBN:
- 9780191707919
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199202973.003.0006
- Subject:
- Mathematics, Applied Mathematics
This chapter studies the smoothing effect and decay rates for the FDE in the subcritical range m < mc , and also for the critical exponent mc = (n - 2)/n. ...
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This chapter studies the smoothing effect and decay rates for the FDE in the subcritical range m < mc , and also for the critical exponent mc = (n - 2)/n. While advancing some of the results, which are valid for the whole subcritical range m < mc , it focuses on the case m > 0. The chapter is organized as follows. Section 5.2 contains the proof of extinction of solutions in the Marcinkiewicz space Mp* (R n), that is characterized as the natural extinction space among all the spaces Mp (R n) and Lp (R n). Section 5.3 considers the question of necessary conditions and the continuity of the extinction time T as a function of u0. Section 5.4 deals with the construction of the global self-similar solutions that increase their space decay rate for positive time. Section 5.5 explains how and where whole mass is lost in the process of extinction. Section 5.6 studies forward effects when dealing with the critical exponent m = mc with starting space L1 . Finally, Section 5.7 discusses extinction as a form of blow-up after a suitable change of variables.Less
This chapter studies the smoothing effect and decay rates for the FDE in the subcritical range m < mc , and also for the critical exponent mc = (n - 2)/n. While advancing some of the results, which are valid for the whole subcritical range m < mc , it focuses on the case m > 0. The chapter is organized as follows. Section 5.2 contains the proof of extinction of solutions in the Marcinkiewicz space Mp* (R n), that is characterized as the natural extinction space among all the spaces Mp (R n) and Lp (R n). Section 5.3 considers the question of necessary conditions and the continuity of the extinction time T as a function of u0. Section 5.4 deals with the construction of the global self-similar solutions that increase their space decay rate for positive time. Section 5.5 explains how and where whole mass is lost in the process of extinction. Section 5.6 studies forward effects when dealing with the critical exponent m = mc with starting space L1 . Finally, Section 5.7 discusses extinction as a form of blow-up after a suitable change of variables.
Juan Luis Vázquez
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780199202973
- eISBN:
- 9780191707919
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199202973.003.0008
- Subject:
- Mathematics, Applied Mathematics
This chapter deals with the actual asymptotic behaviour of the solutions of the FDE in the exponent range 0 < m < mc . This behaviour depends on the class of initial data. The ...
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This chapter deals with the actual asymptotic behaviour of the solutions of the FDE in the exponent range 0 < m < mc . This behaviour depends on the class of initial data. The chapter is interested in ‘small solutions’ that extinguish in finite time, according to the results of Chapter 5. It concentrates on solutions that start with initial data in L 1(R n), or solutions that fall into this class for positive times prior to extinction. In the range m < mc the ZKB solutions provide the clue to the asymptotics for all non-negative solutions with L 1-data.Less
This chapter deals with the actual asymptotic behaviour of the solutions of the FDE in the exponent range 0 < m < mc . This behaviour depends on the class of initial data. The chapter is interested in ‘small solutions’ that extinguish in finite time, according to the results of Chapter 5. It concentrates on solutions that start with initial data in L 1(R n), or solutions that fall into this class for positive times prior to extinction. In the range m < mc the ZKB solutions provide the clue to the asymptotics for all non-negative solutions with L 1-data.
Richard C. Tinsley
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198529873
- eISBN:
- 9780191712777
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198529873.003.0007
- Subject:
- Biology, Disease Ecology / Epidemiology
There is good physiological documentation of the survival of parasites (generally the ‘off-host’ stages) in environments that would be considered hostile to life and characterized by freezing, ...
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There is good physiological documentation of the survival of parasites (generally the ‘off-host’ stages) in environments that would be considered hostile to life and characterized by freezing, extreme desiccation, and so on. Equivalent adaptations may occur in free-living organisms, and are not therefore a feature of parasitism. However, these mechanisms are relevant to the ability of some parasites to persist in ecosystems at the margins of survival of life (as in hot and cold deserts). It is a feature of many such severe environments that constraints are relaxed periodically, even if very briefly, creating a ‘window of opportunity’ when transfer from host to host may occur. It is of even greater interest that, in some cases, transmission may continue even when external conditions appear to be most extreme and when it might be predicted that transmission should be arrested. In these situations, the host is typically regarded as the ‘safe’ environment while the external environment is viewed as hostile. In contrast, there is now abundant evidence that the host actually represents the most hostile environment in the parasite’s life cycle, constituting a finely tuned ‘killing machine’. The mechanisms of the various lethal factors are well documented, together with the reciprocal parasite adaptations for evasion and suppression of attack. This review takes an ecological perspective. Variations in parasite infectivity for particular host types and in host susceptibility to infection determine that some ‘environments’ (hosts) are more hostile than others. The shifting balance between prevailing host and parasite types determines the ability of parasites to persist in the spectrum of environments within the ecosystem. Even the ‘favourable’ environments (in which surviving infections reproduce) may be responsible for major mortality within parasite populations and this contributes to the regulation of the interactions.Less
There is good physiological documentation of the survival of parasites (generally the ‘off-host’ stages) in environments that would be considered hostile to life and characterized by freezing, extreme desiccation, and so on. Equivalent adaptations may occur in free-living organisms, and are not therefore a feature of parasitism. However, these mechanisms are relevant to the ability of some parasites to persist in ecosystems at the margins of survival of life (as in hot and cold deserts). It is a feature of many such severe environments that constraints are relaxed periodically, even if very briefly, creating a ‘window of opportunity’ when transfer from host to host may occur. It is of even greater interest that, in some cases, transmission may continue even when external conditions appear to be most extreme and when it might be predicted that transmission should be arrested. In these situations, the host is typically regarded as the ‘safe’ environment while the external environment is viewed as hostile. In contrast, there is now abundant evidence that the host actually represents the most hostile environment in the parasite’s life cycle, constituting a finely tuned ‘killing machine’. The mechanisms of the various lethal factors are well documented, together with the reciprocal parasite adaptations for evasion and suppression of attack. This review takes an ecological perspective. Variations in parasite infectivity for particular host types and in host susceptibility to infection determine that some ‘environments’ (hosts) are more hostile than others. The shifting balance between prevailing host and parasite types determines the ability of parasites to persist in the spectrum of environments within the ecosystem. Even the ‘favourable’ environments (in which surviving infections reproduce) may be responsible for major mortality within parasite populations and this contributes to the regulation of the interactions.
Sadiah Qureshi
- Published in print:
- 2013
- Published Online:
- January 2014
- ISBN:
- 9780197265413
- eISBN:
- 9780191760464
- Item type:
- chapter
- Publisher:
- British Academy
- DOI:
- 10.5871/bacad/9780197265413.003.0012
- Subject:
- History, World Modern History
Early modern writers had long noted the apparent decimation of some indigenous peoples. However, such discussions took on a new and urgent form in the nineteenth century as a new scientific ...
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Early modern writers had long noted the apparent decimation of some indigenous peoples. However, such discussions took on a new and urgent form in the nineteenth century as a new scientific understanding of extinction as an endemic natural process was established. Many scholars have explored the notion of dying races in histories of colonial contact, modern land rights, or genocide; yet most have overlooked the new epistemological status of extinction as a mechanism for explaining natural change. This chapter explores how this scientific shift became combined with notions of wilderness in the American context to rationalize policies of Indian dispossession, forced removal from their traditional homelands, and the establishment of the world's first national parks. In doing so, it highlights fruitful directions for future histories of heritage, endangerment, and conservation.Less
Early modern writers had long noted the apparent decimation of some indigenous peoples. However, such discussions took on a new and urgent form in the nineteenth century as a new scientific understanding of extinction as an endemic natural process was established. Many scholars have explored the notion of dying races in histories of colonial contact, modern land rights, or genocide; yet most have overlooked the new epistemological status of extinction as a mechanism for explaining natural change. This chapter explores how this scientific shift became combined with notions of wilderness in the American context to rationalize policies of Indian dispossession, forced removal from their traditional homelands, and the establishment of the world's first national parks. In doing so, it highlights fruitful directions for future histories of heritage, endangerment, and conservation.
David M. Wilkinson
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780198568469
- eISBN:
- 9780191717611
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198568469.003.0010
- Subject:
- Biology, Ecology
The ecology of a planet is influenced by historical processes. At any stage in its development, the current conditions of life on a planet form the starting point from which new conditions develop. ...
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The ecology of a planet is influenced by historical processes. At any stage in its development, the current conditions of life on a planet form the starting point from which new conditions develop. This means that over time, an ever increasing number of historical accidents will be incorporated into the system and so the role of past history will become increasingly important. This happens across a range of scales, from the chance long distance dispersal of seeds, to the survival of mass extinction events. Gould's interpretation of the Burgess Shale is discussed as a well-known example of the potential importance of historical contingency. The idea of historical contingency is a simple one and yet it is crucially important in understanding much of ecology. This constrained the possible subsequent trajectories of ecological development on Earth.Less
The ecology of a planet is influenced by historical processes. At any stage in its development, the current conditions of life on a planet form the starting point from which new conditions develop. This means that over time, an ever increasing number of historical accidents will be incorporated into the system and so the role of past history will become increasingly important. This happens across a range of scales, from the chance long distance dispersal of seeds, to the survival of mass extinction events. Gould's interpretation of the Burgess Shale is discussed as a well-known example of the potential importance of historical contingency. The idea of historical contingency is a simple one and yet it is crucially important in understanding much of ecology. This constrained the possible subsequent trajectories of ecological development on Earth.
Eric Post
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691148472
- eISBN:
- 9781400846139
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691148472.003.0002
- Subject:
- Biology, Ecology
This chapter explores the dynamics of plant and animal species and species assemblages during the Earth's most recent period of rapid warming to garner insights into the potential consequences of ...
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This chapter explores the dynamics of plant and animal species and species assemblages during the Earth's most recent period of rapid warming to garner insights into the potential consequences of future rapid climate change. From the perspective of climate change ecology, the Late Pleistocene and the Pleistocene–Holocene transition are relevant because they represent the end of a prolonged period of climatic fluctuation on multiple temporal scales followed by rapid warming. Not only did Earth's major biomes undergo extensive compositional changes during the late Quaternary and near the termination of the Pleistocene epoch, they also underwent geographically large-scale redistributions, and did so rapidly, in some cases on the scale of decades. If rapid warming during the Pleistocene–Holocene transition contributed to—or even acted as the main driver of—mass extinctions, such a scenario would seem to suggest that contemporary climate change has a similar capacity to precipitate species losses.Less
This chapter explores the dynamics of plant and animal species and species assemblages during the Earth's most recent period of rapid warming to garner insights into the potential consequences of future rapid climate change. From the perspective of climate change ecology, the Late Pleistocene and the Pleistocene–Holocene transition are relevant because they represent the end of a prolonged period of climatic fluctuation on multiple temporal scales followed by rapid warming. Not only did Earth's major biomes undergo extensive compositional changes during the late Quaternary and near the termination of the Pleistocene epoch, they also underwent geographically large-scale redistributions, and did so rapidly, in some cases on the scale of decades. If rapid warming during the Pleistocene–Holocene transition contributed to—or even acted as the main driver of—mass extinctions, such a scenario would seem to suggest that contemporary climate change has a similar capacity to precipitate species losses.
Eric Post
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691148472
- eISBN:
- 9781400846139
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691148472.003.0007
- Subject:
- Biology, Ecology
This chapter examines the relationship between species diversity and ecosystem function and stability. This subject is currently one of the most intensely studied topics in ecology. It is also of ...
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This chapter examines the relationship between species diversity and ecosystem function and stability. This subject is currently one of the most intensely studied topics in ecology. It is also of paramount importance in the study of the ecological consequences of climate change, most probably because of its obvious relevance to ecosystem goods and services. More classically, however, the subject of biodiversity response to climate change relates to what factors set limits to the upper and lower bounds of species diversity and how those factors might be altered by rapid climate change. Of the two processes generating diversity—speciation and immigration—the latter obviously operates at shorter time scales and is likely to respond more immediately to climate change. Of the processes reducing local diversity—extinction and emigration—the latter is, again, likely to operate at shorter time scales, but both processes are likely to be influenced by climate change, although at potentially different timescales.Less
This chapter examines the relationship between species diversity and ecosystem function and stability. This subject is currently one of the most intensely studied topics in ecology. It is also of paramount importance in the study of the ecological consequences of climate change, most probably because of its obvious relevance to ecosystem goods and services. More classically, however, the subject of biodiversity response to climate change relates to what factors set limits to the upper and lower bounds of species diversity and how those factors might be altered by rapid climate change. Of the two processes generating diversity—speciation and immigration—the latter obviously operates at shorter time scales and is likely to respond more immediately to climate change. Of the processes reducing local diversity—extinction and emigration—the latter is, again, likely to operate at shorter time scales, but both processes are likely to be influenced by climate change, although at potentially different timescales.
Eric Post
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691148472
- eISBN:
- 9781400846139
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691148472.003.0009
- Subject:
- Biology, Ecology
This concluding chapter argues that Earth's climate is warming at a pace that may very well be unprecedented, and it is doing so from a higher baseline average temperature than that which was the ...
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This concluding chapter argues that Earth's climate is warming at a pace that may very well be unprecedented, and it is doing so from a higher baseline average temperature than that which was the starting point for the most recent episode of rapid warming, which signaled the end of the Pleistocene and the demise of most of its large mammals. That most recent warming episode also coincided with geographically widespread biome shifts. Perhaps more tellingly, current warming, still in its early stages, has already heralded similarly geographically widespread and taxonomically broad shifts in phenological dynamics, population dynamics, species distributions, and ecosystem carbon dynamics. Indeed, some have asserted that Earth may be on the threshold of the sixth major extinction event.Less
This concluding chapter argues that Earth's climate is warming at a pace that may very well be unprecedented, and it is doing so from a higher baseline average temperature than that which was the starting point for the most recent episode of rapid warming, which signaled the end of the Pleistocene and the demise of most of its large mammals. That most recent warming episode also coincided with geographically widespread biome shifts. Perhaps more tellingly, current warming, still in its early stages, has already heralded similarly geographically widespread and taxonomically broad shifts in phenological dynamics, population dynamics, species distributions, and ecosystem carbon dynamics. Indeed, some have asserted that Earth may be on the threshold of the sixth major extinction event.
David Benatar
- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780199296422
- eISBN:
- 9780191712005
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199296422.003.0006
- Subject:
- Philosophy, Moral Philosophy
This chapter discusses the implications of the earlier arguments for population and extinction. It is argued that the anti-natal view solves various problems in moral theory about population, ...
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This chapter discusses the implications of the earlier arguments for population and extinction. It is argued that the anti-natal view solves various problems in moral theory about population, including many made famous by Derek Parfit. Anti-natalism is compatible with his Theory X. It solves the non-identity problem, avoids the repugnant conclusion and the mere addition problem, and explains asymmetry. Turning to contractarianism, the chapter shows how anti-natalism is a consequence of maximin in John Rawls' original position. It considers the question whether human extinction, an implication of anti-natalism, may be phased or whether it should come as quickly as possible. Finally, it is argued that the state of human extinction, where it is brought about by failing to produce new people (rather than by killing off existing people), is not bad.Less
This chapter discusses the implications of the earlier arguments for population and extinction. It is argued that the anti-natal view solves various problems in moral theory about population, including many made famous by Derek Parfit. Anti-natalism is compatible with his Theory X. It solves the non-identity problem, avoids the repugnant conclusion and the mere addition problem, and explains asymmetry. Turning to contractarianism, the chapter shows how anti-natalism is a consequence of maximin in John Rawls' original position. It considers the question whether human extinction, an implication of anti-natalism, may be phased or whether it should come as quickly as possible. Finally, it is argued that the state of human extinction, where it is brought about by failing to produce new people (rather than by killing off existing people), is not bad.
