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Documents  92C30 | enregistrements trouvés : 10

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- 177 p.
ISBN 978-0-8218-2816-8

Proceedings of symposia in applied mathematics , 0059

Localisation : Collection 1er étage

modélisation mathématique appliquée à la biologie # EDP # équation différentielle # équation réaction/diffusion # processus naissance et mort #dynamique # bifurcation

92C05 ; 92C20 ; 92C30 ; 92C37 ; 92D10 ; 92D30

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Research talks;Dynamical Systems and Ordinary Differential Equations;Mathematics in Science and Technology

Oxygen is essential for burning food and generate energy, but may become limiting for aquatic organisms that rely on gas exchange under water. This is because breathing under water is challenging: the diffusion of oxygen is orders of magnitude lower in water than in air, while the higher density and viscosity of water greatly enhance the cost of breathing. Given that oxygen may be also be a limiting resource, respiration physiology may be relevant to understand energy budgets in aquatic ectotherms.
Traditionally, respiration physiology has focused on the benefits of extracting sufficient amounts of oxygen and thus prevent asphyxiation. However, breathing oxygen is intrinsically dangerous: while a shortage of oxygen quickly leads to asphyxiation, too much oxygen is toxic. Therefore, the ability to regulate oxygen consumption rates (i.e. respiratory control) is at a premium; good respiratory control will enable ectotherms to balance oxygen toxicity against the risk of asphyxiation across a wide range of temperatures.
In this presentation I will focus on the effects of body size and temperature on this balancing act with regard to oxygen uptake and consumption. Body size is intimately tied to oxygen budgets and hence energy budgets through size related changes in oxygen requirements and respiratory surfaces. Furthermore, a larger body size may represent a respiratory advantage that helps to overcome viscosity. Given that viscous forces are larger in cold water, this respiratory advantage represents a novel explanation for the pattern of larger body sizes in cold water, with polar gigantism as the extreme manifestation.
Temperature is also intimately tied to oxygen budgets and hence energy budgets through thermal controls on metabolism and temperature related changes in the availability of dissolved oxygen (notably diffusivity, viscosity and solubility). Thus, differences in temperatures may act more strongly on ectotherms that rely on aquatic rather than on aerial gas exchange. Comparing four different insect orders, I demonstrate that thermal tolerance is indeed affected more by the prevalent oxygen conditions in species with poor respiration control. In conclusion, the ability to regulate gas exchange (i.e. respiratory control) is thus a key attribute of species that helps to explain thermal responses from an oxygen perspective.
Oxygen is essential for burning food and generate energy, but may become limiting for aquatic organisms that rely on gas exchange under water. This is because breathing under water is challenging: the diffusion of oxygen is orders of magnitude lower in water than in air, while the higher density and viscosity of water greatly enhance the cost of breathing. Given that oxygen may be also be a limiting resource, respiration physiology may be ...

92D25 ; 92D50 ; 92C15 ; 92C30

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Research talks;Mathematics in Science and Technology

In this talk we overview some of the challenges of cardiac modeling and simulation of the electrical depolarization of the heart. In particular, we will present a strategy allowing to avoid the 3D simulation of the thin atria depolarization but only solve an asymptotic consistent model on the mid-surface. In a second part, we present a strategy for estimating a cardiac electrophysiology model from front data measurements using sequential parallel data assimilation strategy. In this talk we overview some of the challenges of cardiac modeling and simulation of the electrical depolarization of the heart. In particular, we will present a strategy allowing to avoid the 3D simulation of the thin atria depolarization but only solve an asymptotic consistent model on the mid-surface. In a second part, we present a strategy for estimating a cardiac electrophysiology model from front data measurements using sequential ...

92C30 ; 35Q92 ; 65C20

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Research talks;Dynamical Systems and Ordinary Differential Equations;Mathematics in Science and Technology

Energy investment into maturation encompasses any expenses linked to tissue differentiation, i.e. re-organization of body structure during development. This is different from growth which can be conceptualized as synthesis of more of the same. Energy invested into growth is fixed into the biomass of the organism (with some overheads), but energy invested in maturation is oxidized as metabolic work making it more difficult to quantify in practice. Nonetheless it can be quantified and it can even represent a substantial part of the energy budget of living organisms. In this talk I will give an overview of different studies where investment in maturity was quantified. The focus will be on 4 different types of organisms: cnidarians, ctenophores, teleost fish and frogs. I will further discuss what type of eco-physiological effects might be expected when an organism modifies its investment into these processes. Some intriguing literature studies will be presented which can be re-interpreted in perhaps unexpected ways when investment into maturation is taken into account. This raises the question of just how important and how flexible such costs might actually be. Maturity can be used as a quantifier for internal time. Seven criteria were proposed which should be respected by any such metric: (1) independent of morphology, (2) independent of body size, (3) depend on one a priori homologous event, (4) unaffected by changes in temperature, (5) similar between closely related species, (6) increase with clock time, and (7) physically quantifiable (Reiss 1989). We showed that the maturity concept of Dynamic Energy Budget theory complies with all those criteria and on the basis of this information and the studies presented above I will finish by discussing the potential role of maturity in shaping metabolic flexibility. Energy investment into maturation encompasses any expenses linked to tissue differentiation, i.e. re-organization of body structure during development. This is different from growth which can be conceptualized as synthesis of more of the same. Energy invested into growth is fixed into the biomass of the organism (with some overheads), but energy invested in maturation is oxidized as metabolic work making it more difficult to quantify in ...

92D25 ; 92D40 ; 92C30

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- 202 p.
ISBN 978-3-540-25439-3

Lecture notes in mathematics , 1867

Localisation : Collection 1er étage

mathématique de la biologie # modèle biologique # physiologie # biochimie

92C30 ; 92C40 ; 92-06 ; 00B15

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- 90 p.

CBMS-NSF regional conference series in applied mathematics , 0010

Localisation : Collection 1er étage

analyse par traceur de système physiologique # biologie et mathématique # cinétique d'ensyme # diffusion en biologie # flux de sang # population de cellule # système circulatoire

92Bxx ; 92C30 ; 92C35 ; 92C45 ; 92Cxx

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- 766 p.
ISBN 978-0-387-98381-3

Interdisciplinary applied mathematics , 0008

Localisation : Ouvrage RdC (KEEN)

physiologie # biomathématique # biochimie # cinétique # physiologie cellulaire # physiologie des systèmes # modèle mathématique

92C30 ; 92-01 ; 92C40 ; 92C45

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- 354 p.
ISBN 978-0-387-95072-3

Texts in applied mathematics , 0010

Localisation : Ouvrage RdC (HOPP)

modélisation # simulation informatique # biomathématique # biométrie # population # physiologie # hérédité # épidémiologie # système nerveux # exercice # MATLAB

92-01 ; 92B05 ; 92D99 ; 92C30 ; 92D25 ; 92D30

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- 32 p.

Actualités scientifiques et industrielles , 0931

Localisation : Ouvrage RdC (BOIV)

biochimie # biologie # chimie # colloidaux # virus

92C30 ; 94C40

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- 127 p.

Localisation : Ouvrage RdC (PERE)

animation virtuelle # axe médian # carpe # carte de distances # distance discrète # dynamique # détection de contact # imagerie médicale # intégration différentielle # modèle physique # modélisation 3D

68U10 ; 92-04 ; 92C10 ; 92C25 ; 92C30

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