No. Galis F, Metz JAJ: Why are there so many Cichlid Species? On the Interplay of Speciation and ... more No. Galis F, Metz JAJ: Why are there so many Cichlid Species? On the Interplay of Speciation and Adaptive Radiation.
International Journal of Bifurcation and Chaos, Feb 1, 2000
We investigate the local bifurcations experienced by a time-discrete dynamical system from popula... more We investigate the local bifurcations experienced by a time-discrete dynamical system from population biology when there is an attractor in an invariant subspace that loses stability. The system describes competition between two species in a constant environment; invariant subspaces contain single-species attractors; the loss of stability of the attractor in one invariant subspace means that the corresponding species (i.e. the "resident" species) becomes invadable by its competitor. The global dynamics may be understood by examining the sign structure of Lyapunov exponents transverse to the invariant subspace. When the transverse Lyapunov exponent (computed for the natural measure) changes from negative to positive on varying a parameter, the system experiences a so-called blowout bifurcation. We unfold two generic scenarios associated with blowout bifurcations: (1) a codimension-2 bifurcation involving heteroclinic chaos and on–off intermittency and (2) a sequence of riddling bifurcations that cause asymptotic indeterminacy. An ingredient that both scenarios have in common is the fact that the "resident" species subspace contains multiple invariant sets with transverse Lyapunov exponents that do not change sign simultaneously. This simple model adds on a short list of archetypical systems that are needed to investigate the structure of blowout bifurcations. From a biological viewpoint, the results imply that mutual invasibility in a constant environment is neither a necessary nor a sufficient condition for coexistence.
HAL (Le Centre pour la Communication Scientifique Directe), 2000
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
Supporting Material for the paper: "Local adaptation, dispersal evolution, and the spatial e... more Supporting Material for the paper: "Local adaptation, dispersal evolution, and the spatial eco-evolutionary dynamics of invasion"<br>
Keywords: Non-Linear Dynamics Note: Abstract Reference LANOS-CONF-1998-029 Record created on 2004... more Keywords: Non-Linear Dynamics Note: Abstract Reference LANOS-CONF-1998-029 Record created on 2004-12-03, modified on 2017-05-12
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
The Journal of the Acoustical Society of America, 2020
Natural soundscapes correspond to the acoustical patterns produced by biological and geophysical ... more Natural soundscapes correspond to the acoustical patterns produced by biological and geophysical sound sources at different spatial and temporal scales for a given habitat. This pilot study aims to characterize the temporal-modulation information available to humans when perceiving variations in soundscapes within and across natural habitats. This is addressed by processing soundscapes from a previous study [Krause, Gage, and Joo. (2011). Landscape Ecol. 26, 1247] via models of human auditory processing extracting modulation at the output of cochlear filters. The soundscapes represent combinations of elevation, animal, and vegetation diversity in four habitats of the biosphere reserve in the Sequoia National Park (Sierra Nevada, USA). Bayesian statistical analysis and support vector machine classifiers indicate that: (i) amplitude-modulation (AM) and frequency-modulation (FM) spectra distinguish the soundscapes associated with each habitat; and (ii) for each habitat, diurnal and sea...
With thousands of exoplanets now identified, the characterization of habitable planets and the po... more With thousands of exoplanets now identified, the characterization of habitable planets and the potential identification of inhabited ones is a major challenge for the coming decades. We review the current working definition of habitable planets, the upcoming observational prospects for their characterization and present an innovative approach to assess habitability and inhabitation. This integrated method couples for the first time the atmosphere and the interior modeling with the biological activity based on ecosystem modeling. We review here the first applications of the method to asses the likelihood and impact of methanogenesis for Enceladus, primitive Earth, and primitive Mars. Informed by these applications for solar system situations where habitability and inhabitation is questionned, we show how the method can be used to inform the design of future space observatories by considering habitability and inhabitation of Earth-like exoplanets around sun-like stars. Résumé. Avec des milliers d'exoplanètes identifiées, la caractérisation des planètes habitables et l'identification potentielle de celles qui seraient habitées est un défi majeur pour les décennies à venir. Nous rappelons en premier lieu la définition des planètes habitables et les perspectives d'observation à venir pour leur caractérisation. Nous présentons ensuite une approche innovante pour évaluer l'habitabilité et l'habitation pour des systèmes extraterrestres. Cette méthode intégrée couple pour la première fois la modélisation de l'atmosphère et de l'intérieur planétaires avec l'activité biologique basée sur la modélisation des écosystèmes.
No. Galis F, Metz JAJ: Why are there so many Cichlid Species? On the Interplay of Speciation and ... more No. Galis F, Metz JAJ: Why are there so many Cichlid Species? On the Interplay of Speciation and Adaptive Radiation.
International Journal of Bifurcation and Chaos, Feb 1, 2000
We investigate the local bifurcations experienced by a time-discrete dynamical system from popula... more We investigate the local bifurcations experienced by a time-discrete dynamical system from population biology when there is an attractor in an invariant subspace that loses stability. The system describes competition between two species in a constant environment; invariant subspaces contain single-species attractors; the loss of stability of the attractor in one invariant subspace means that the corresponding species (i.e. the "resident" species) becomes invadable by its competitor. The global dynamics may be understood by examining the sign structure of Lyapunov exponents transverse to the invariant subspace. When the transverse Lyapunov exponent (computed for the natural measure) changes from negative to positive on varying a parameter, the system experiences a so-called blowout bifurcation. We unfold two generic scenarios associated with blowout bifurcations: (1) a codimension-2 bifurcation involving heteroclinic chaos and on–off intermittency and (2) a sequence of riddling bifurcations that cause asymptotic indeterminacy. An ingredient that both scenarios have in common is the fact that the "resident" species subspace contains multiple invariant sets with transverse Lyapunov exponents that do not change sign simultaneously. This simple model adds on a short list of archetypical systems that are needed to investigate the structure of blowout bifurcations. From a biological viewpoint, the results imply that mutual invasibility in a constant environment is neither a necessary nor a sufficient condition for coexistence.
HAL (Le Centre pour la Communication Scientifique Directe), 2000
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
Supporting Material for the paper: "Local adaptation, dispersal evolution, and the spatial e... more Supporting Material for the paper: "Local adaptation, dispersal evolution, and the spatial eco-evolutionary dynamics of invasion"<br>
Keywords: Non-Linear Dynamics Note: Abstract Reference LANOS-CONF-1998-029 Record created on 2004... more Keywords: Non-Linear Dynamics Note: Abstract Reference LANOS-CONF-1998-029 Record created on 2004-12-03, modified on 2017-05-12
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
The Journal of the Acoustical Society of America, 2020
Natural soundscapes correspond to the acoustical patterns produced by biological and geophysical ... more Natural soundscapes correspond to the acoustical patterns produced by biological and geophysical sound sources at different spatial and temporal scales for a given habitat. This pilot study aims to characterize the temporal-modulation information available to humans when perceiving variations in soundscapes within and across natural habitats. This is addressed by processing soundscapes from a previous study [Krause, Gage, and Joo. (2011). Landscape Ecol. 26, 1247] via models of human auditory processing extracting modulation at the output of cochlear filters. The soundscapes represent combinations of elevation, animal, and vegetation diversity in four habitats of the biosphere reserve in the Sequoia National Park (Sierra Nevada, USA). Bayesian statistical analysis and support vector machine classifiers indicate that: (i) amplitude-modulation (AM) and frequency-modulation (FM) spectra distinguish the soundscapes associated with each habitat; and (ii) for each habitat, diurnal and sea...
With thousands of exoplanets now identified, the characterization of habitable planets and the po... more With thousands of exoplanets now identified, the characterization of habitable planets and the potential identification of inhabited ones is a major challenge for the coming decades. We review the current working definition of habitable planets, the upcoming observational prospects for their characterization and present an innovative approach to assess habitability and inhabitation. This integrated method couples for the first time the atmosphere and the interior modeling with the biological activity based on ecosystem modeling. We review here the first applications of the method to asses the likelihood and impact of methanogenesis for Enceladus, primitive Earth, and primitive Mars. Informed by these applications for solar system situations where habitability and inhabitation is questionned, we show how the method can be used to inform the design of future space observatories by considering habitability and inhabitation of Earth-like exoplanets around sun-like stars. Résumé. Avec des milliers d'exoplanètes identifiées, la caractérisation des planètes habitables et l'identification potentielle de celles qui seraient habitées est un défi majeur pour les décennies à venir. Nous rappelons en premier lieu la définition des planètes habitables et les perspectives d'observation à venir pour leur caractérisation. Nous présentons ensuite une approche innovante pour évaluer l'habitabilité et l'habitation pour des systèmes extraterrestres. Cette méthode intégrée couple pour la première fois la modélisation de l'atmosphère et de l'intérieur planétaires avec l'activité biologique basée sur la modélisation des écosystèmes.
In this article, we apply the perspective of intraorganismal ecology by investigating a family of... more In this article, we apply the perspective of intraorganismal ecology by investigating a family of ecological models suitable to describe a gene therapy for a particular metabolic disorder, the adenosine deaminase deficiency. The gene therapy is modeled as the prospective ecological invasion of an organ (here, bone marrow) by genetically modified stem cells, which then operate niche construction in the cellular environment by releasing an enzyme they synthesize. We show that depending on the order chosen for the model (a choice that cannot be made on a priori assumptions), different kinds of dynamics are expected, possibly leading to different therapeutic strategies. This drives us to discuss several features of the extension of ecology to intraorganismal ecology.
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Papers by Régis Ferrière