Дисертації з теми "Extinction (biologie) – Modèles mathématiques"
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Gaucel, Sébastien. "Analyse mathématique et simulations d'un modèle prédateur-proie en milieu insulaire hétérogène." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2005. http://tel.archives-ouvertes.fr/tel-00263910.
Fabre, Virginie. "Réponse démographique des Néandertaliens face aux pressions environnementales du stade isotopique 3 : approche par modélisation écologique." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX20711/document.
The Neanderthal population lived and thrived in Europe during about 300ky in Middle Pleistocene. The causes of their disappearance about 30ky ago are strongly debated. Among the current hypotheses developed to explain this demographical crisis, competition with Modern humans, climate changes, epidemic diseases or demographical changes have often been evoked. The aim of this thesis was to re-analyse these assumptions and their determinants by using mathematical modelling. Models are used here to synthesize the data obtained by classical paleoanthropological studies and try to understand the complex and unknown phenomenon relative to the dramatic demographic fluctuation observed in Neanderthal populations during OIS3. Classical mathematical models are firstly used to analyse the influence of both demographical parameters and environmental stresses on the Neanderthal population. Next, we created new deterministic models more specified to the Neanderthal population. After checking the relevance of these models, we used them to analyse the demographical crisis of OIS3 and the information given by modelling have been checked with the information supplied by classical paleoanthropological, zooarchaeological and prehistorical studies. Our results allowed us to exclude the assumption of an epidemic disease or a climate change or even a resource competition as a cause of Neanderthal extinction whereas competition in a broad sense and above all demographic change could have led, under specific conditions, to Neanderthal demise. A demographic modification in the Neanderthal population across the time, in terms of fecundity or maturation speed, could be the reason of Neanderthals disappearance
Ed-Darraz, Abdelkarim. "Modèles de dynamique des populations dans un environnement aléatoire." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066591/document.
This thesis addresses some issues associated with population dynamics in random environment. Random environment is described by a Markov process with values in a finite space and which, involve certain forces on the choice of vital rates, will lead the population dynamics. When the dynamic is modeled by a birth and death process, we will answer the question : When almost surely extinction settled ? (Bacaër and Ed-Darraz, 2014). In (Ed-Darraz and Khaladi, 2015) we are interested to the final size of an epidemic in random environment. J Math Biol. 69 (1) :73-90 Ed-Darraz A, Khaladi M (2015) On the final epidemic size in random environnement, Math. Biosc 266 : 10-14
Zalduendo, Vidal Nicolás Mauricio. "Processus de branchement bi-sexués multi-types." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0285.
The bisexual Galton-Watson process, introduced by Daley, is an extension of the classical Galton-Watson process, but taking into account the mating of females and males, which form couples that can accomplish reproduction. Properties such as extinction conditions and asymptotic behaviour have been studied in the past years in the single-type case, but multi-type versions have only been treated in some particular cases. In this thesis we deal with a general multi-dimensional version of Daley's model, where we consider different types of females and males, which mate according to a “mating function”. We consider that this function is superadditive, which in simple words implies that two groups of females and males will form a larger number of couples together rather than separate. One of the main difficulties in the study of this process is the absence of a linear operator that is the key to understand its behavior in the asexual case, but in our case it turns out to be only concave. To overcome this issue, we use a concave Perron-Frobenius theory which ensures the existence of eigen-elements for some concave operators. Using this tool, we find a necessary and sufficient condition for almost sure extinction as well as laws of large numbers. We also study the convergence of the process in the long-time through the identification of a supermartingale, and the existence of quasi-stationary distributions for the subcritical regime. Finally, some extensions to models with random mating function and models in continuous time are considered
Pellegrin, Xavier. "Oscillations dans des modèles mathématiques issus de la biologie." Paris 7, 2014. http://www.theses.fr/2014PA077263.
Ln this report, we focus on mathematical analysis of two models coming from biology. The first model, a Kuramoto model, describes the time-evolution of a large number of mean-field coupled phase oscillators. The second one is an original oscillation model, based on a singuiar perturbation of a delayed differential equation. It had been introduced in relation with oscillatory patterns observed in neural networks, and it is subject fo mathematical analysis since the 1980's
Djermoune, Makhlouf. "Explosion et extinction de la température dans les matériaux viscoplastiques thermo-adoucissants." Metz, 1999. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1999/Djermoune.Makhlouf.SMZ9946.pdf.
Yoccoz, Gilles Nigel. "Le rôle du modèle euclidien d'analyse des données en biologie évolutive." Lyon 1, 1988. http://www.theses.fr/1988LYO10111.
Cardin-Bernier, Guillaume. "Simplification de modèles mathématiques représentant des cultures cellulaires." Thèse, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/8159.
Baup, Stéphane. "Elimination de pesticides sur lit de charbon actif en grain en présence de matière organique naturelle : élaboration d'un protocole couplant expériences et calculs numériques afin de simuler les équilibres et les cinétiques compétitifs d'adsorption." Poitiers, 2000. https://tel.archives-ouvertes.fr/tel-00983252.
Consalvi, Jean-Louis. "Développement d'un modèle diphasique dédié au calcul de l'interaction d'un brouillard d'eau et d'un feu en milieu compartimenté : application à la lutte incendie." Aix-Marseille 1, 2002. http://www.theses.fr/2002AIX11058.
Costa, Manon. "Modélisation probabiliste et éco-évolutionnaire des communautés proies-prédateurs." Palaiseau, Ecole polytechnique, 2015. http://www.theses.fr/2015EPXX0038.
Lesquoy-de, Turckheim Élisabeth. "Statistique et biologie : quelques exemples de modélisation." Paris 11, 1985. http://www.theses.fr/1985PA112382.
This thesis is a collection of five papers. Three of them are collective papers including biologists and show an example of the uses of statistics in biology. One is a methodological hint about regression models and the last presents the probabilistic bases for modelling survival analysis with point processes
Mirrahimi, Sepideh. "Phénomènes de concentration dans certaines EDPs issues de la biologie." Paris 6, 2011. http://www.theses.fr/2011PA066165.
Gosselin, Frédéric. "Modèles stochastiques d'extinction de population : propriétés mathématiques et leurs applications." Paris 6, 1997. http://www.theses.fr/1997PA066358.
Mesplé, Fabrice. "Modélisation des processus biologiques et physico-chimiques dans un écosystème aquatique eutrophe : le lagunage à haut rendement." Montpellier 1, 1993. http://www.theses.fr/1993MON13514.
Diaz-Zuccarini, Vanessa Alexandra. "Étude des conditions d'efficacité du ventricule gauche par optimisation téléonomique d'un modèle de son fonctionnement." Lille 1, 2003. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2003/50376-2003-287-288.pdf.
Devys, Anne. "Modélisation, analyse mathématique et simulation numérique de problèmes issus de la biologie." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10087/document.
We investigate four models coming from biological contexts. The first one concerns a model describing the growth of a population of tumors. This model leads to a McKendrick–Von Foerster equation : a conservation law with a non–local boundary condition. We prove the existence and unicity of a solution, then we study, using the general relative entropy, its asymptotic behavior. We provide numerical simulations using WENO scheme. The second part concerns the modelisation of the respiration. First we study the air flux in the bronchial tree using a mulstiscale model. The system present non–usual dissipative boundary conditions. The numerical scheme we use is based on a decomposition idea that reduce the system to the resolution of Stokes problems with standard Dirichlet–Neumann conditions. Then, we propose a model concerning the gas exchanges bringing to light the heterogeneity of the absorption of oxygen along the bronchial tree. The third part concerns the MAPK cascade in Xenopus oocytes. The modelisation leads to an equation of KPP type. A mathematical study shows the existence of travelling waves. Then we provide a detailed numerical study of the system. Finally, the last part, concerns the system of Patlak–Keller–Segel 1D after blow–up. The mathematical study provide a description of the system after blow–up, based on the notion of default meausure. Then we propose a numerical scheme, adopting the optimal transport viewpoint and allowing to simulate the system after blow–up
Poreau, Brice. "Biologie et complexité : histoire et modèles du commensalisme." Phd thesis, Université Claude Bernard - Lyon I, 2014. http://tel.archives-ouvertes.fr/tel-01063917.
André, Jean-Baptiste. "Niveaux de sélection chez les microparasites : virulence, coopération, mutation." Montpellier 2, 2003. http://www.theses.fr/2003MON20172.
Elhallaoui, Menana. "Modélisation moléculaire d'antagonistes non compétitifs du récepteur NMDA [N-Méthyl-D-aspartate]." Bordeaux 2, 1994. http://www.theses.fr/1994BOR2B003.
Duverger, Corinne. "Théorie évolutionnaire et modèles métaphoriques : étude des liens entre l'économie et la biologie." Dijon, 1993. http://www.theses.fr/1993DIJOE011.
This work is concerned by the links between economy and biology in order to understand why economists use biological theory of natural selection. In the first part, we have studied the nature and the function of metaphor and examined links between metaphor and economic models. We have not omitted the relations with the philosophical literature about the cognitive force and linguistic structure of metaphor. And so, we have explained why the gary Becker's model of altruism is perfectible. In the second part, we have studied the links between the theory of games and the evolutionary theory. And we have shown the evolutionary stable strategy can be used in economy and biology
Baratchart, Etienne. "Etude quantitative des aspects dynamiques et spatiaux du développement métastatique à l'aide de modèles mathématiques." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0023/document.
In this thesis, a quantitative study of the metastatic process in the mouse has been performed thanks to mathematical modeling. Precisely, longitudinal data of the total metastatic burden and MRI data on the macrometastatic size distribution are confronted to a mathematical model describing the metastatic process by the independent growths of metastatic foci starting from one or few cells. This \standard" theory, able to describe the dynamics of the total metastatic burden, is on the other hand unable to describe the observed metastatic size distributions. Indeed, this model predicts many small metastases, whereas the observed metastases are much larger and fewer. In order to explain these differences, we proposed two hypotheses that were not taken into account in the initial theory. In the first one, metastases that are growing in close vicinity could merge, resulting in one larger metastasis. In the second one, metastatic foci could attract arriving circulating tumor cells, resulting also in fewer foci but much larger ones. These hypotheses have been tested experimentally by our biologists collaborators, and in silico thanks to a spatial model of tumor growth. The results of this study show that the previously suggested phenomena could have a substantial impact on the number and the sizes of the metastatic foci during metastatic development. Another part of this thesis is devoted to the numerical and mathematical analysis of the previous spatial model. This model takes into account the effect of the pressure on the proliferation of tumor cells. Numerical convergence of the numerical method that has been used and data assimilation on imaging data of pulmonary metastases are presented. Finally, a last part deals with the interactions between metastasis and its supportive stroma. Recent studies shed light on the implication of hematopoietic progenitors in the formation of a permissive soil in the future metastatic site, a phenomenon so-called premetastatic niche. In this thesis, a mathematical model describing the premetastatic and metastatic dynamics is proposed to study quantitative aspects of this phenomenon
Mercado, Cabrera Antonio. "Modélisation de la cinétique chimique d'un plasma en extinction dans un disjoncteur basse tension." Toulouse 3, 2003. http://www.theses.fr/2003TOU30007.
Yeramian, Edouard. "Étude expérimentale et théorique de récepteurs de neuromédiateurs et développement de méthodologies pour l'analyse des signaux." Châtenay-Malabry, Ecole centrale de Paris, 1986. http://www.theses.fr/1986ECAP0032.
Nguyen, Huu Tri. "Echelles de temps et dynamique spatiotemporelle de populations." Aix-Marseille 2, 2007. http://theses.univ-amu.fr.lama.univ-amu.fr/2007AIX22099.pdf.
Aggregation of variables methods allow reducing complexity of models in population dynamics by building simplified models governing fewer variables. We first use those methods to study spatial host-parasitoids models on patches. Those models are composed of a local interaction submodel and a dispersal submodel. Dispersal consists in k events of elementary dispersal on the nearest neighbours. We study the influence of parameter k on global dynamics and persistence of the system. We then develop a model of a virus in a marine environment to study the “plankton paradox”: plankton dynamics violate the principle of competitive exclusion. The study of our system shows that the presence of a virus enables the coexistence of two different species of bacteria
Bonneau, Stephane. "Chemins minimaux en analyse d’images : nouvelles contributions et applications à l’imagerie biologique." Paris 9, 2006. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=2006PA090062.
Introduced first in image analysis to globally minimize the geodesic active contour functionnal, minimal paths techniques are robust tools for extracting open and closed contours from images. Minimal paths are computed by solving the Eikonal equation on a discrete grid with an efficient algorithm called Fast Marching. In this thesis, we present novel approaches based on minimal paths. The interest of these techniques is illustrated by the analysis of biological images. This thesis consists of three parts. In the first part, we review the relevant litterature in boundary-based deformable models and minimal paths techniques. In the second part, we propose a new approach for automatically detecting and tracking, in sequences of 2D fluorescence images, punctual objects which are intermittently visible. Trajectories of moving objects, considered as minimal paths in a spatiotemporal space, are retrieved using a perceptual grouping approach based on front propagation in the 2D+T volume. The third part adresses the problem of surface extraction in 3D images. First, we introduce a front propagation approach to distribute a set of points on a closed surface. Then, we propose a method to extract a surface patch from a single point by constructing a dense network of minimal paths. We finally present an extension of this method to extract a closed surface, in a fast and robust manner, from a few points lying on the surface
Calvez, Vincent. "Modèles et analyses mathématiques pour les mouvements collectifs de cellules." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2007. http://tel.archives-ouvertes.fr/tel-00255811.
Dans une première partie nous étudions plusieurs variantes du modèle PKS classique, incluant notamment une diffusion non-linéaire des cellules, ou bien une loi de diffusion chimique à noyau de Green logarithmique. Puis nous montrons l'existence globale pour une masse sous-critique du modèle PKS classique dans tout l'espace $\mathbb{R}^2$.
On complexifie ensuite le modèle de base en ajoutant un intermédiaire chimique réactionnel, ce qui modifie l'homogénéité du système. Enfin les conditions d'existence globale pour le modèle cinétique ODA avec effets délocalisants sont affaiblies par rapport aux travaux précédents.
Dans une deuxième partie nous appliquons le modèle phénoménologique de PKS, et son principe de masse critique, à un processus d'auto-organisation remarquable dans le cerveau: la sclérose concentrique de Baló. Un couplage adéquat entre un front de propagation et une instabilité de PKS décrit raisonnablement les motifs en anneaux de la maladie.
La troisième partie adopte le point de vue du transport optimal de masse pour analyser le modèle de PKS unidimensionnel modifié auparavant (afin de partager les caractéristiques de PKS 2D). Bien que la fonctionnelle d'énergie ne soit pas convexe par déplacement, nous démontrons la convergence vers un unique état d'équilibre, lorsqu'il existe. Ces nouvelles idées sont mises en oeuvre numériquement~: un flot gradient discret pour la distance de Wasserstein est analysé, puis simulé en dimension un d'espace.
Plusieurs annexes viennent compléter ce travail, dont une annexe qui regroupe tous les aspects numériques de la thèse.
Liu, Ming Gang. "Etude de la texture des membranes et de leur interaction avec des suspensions au cours d'une filtration dynamique." Compiègne, 1992. http://www.theses.fr/1992COMPD496.
Joron, Mathieu. "Coloration avertissante et mimétisme müllérien : le problème de la diversification." Montpellier 2, 2000. http://www.theses.fr/2000MON20197.
Grange, Sophie. "Le grand dilemme des équidés sauvages : coexister avec les bovidés et éviter les grands prédateurs." Poitiers, 2006. http://www.theses.fr/2006POIT2319.
The Plains zebra is currently the most widespread wild equid; however there is still little information on the regulation/limitation of their populations. Comparative studies on the relative abundance and the population dynamics of Plains zebras and grazing bovids support the hypothesis that predation has a greater impact on the number of zebras in African ecosystems, and probably also play an important role in the limitation of some zebra populations. Given these findings, it will be necessary to link population models of zebra and their main predators. However a major problem is the lack of accurate data on zebra survival rates. The study on the population dynamics of Plains zebra in Hwange National Park (Zimbabwe) is the first one to use a capture-mark-recapture method based on photo-identification. After only one year and a half, this method already proves to be promising to study zebra population dynamics. This thesis also shows that the feralization of domestic horses leads to an unnatural population dynamics, which means that Camargue horses cannot be used as surrogates of wild equids to restore natural ecosystems. In terms of species conservation it is therefore now important to acquire a good knowledge on the regulating/limiting factors acting on current wild equid populations in order to facilitate translocations and reintroductions in their natural ecosystems
Géan, Julie. "Réalisation de systèmes membranaires modèles et étude de leur organisation par microscopie à l'angle de Brewster, spéctroscopie PM-IRRAS et dichroi͏̈sme circulaire vibrationnel." Bordeaux 1, 2003. http://www.theses.fr/2003BOR12896.
Martens, Johannes. "L' évolution des organisations biologiques : vers une théorie unifiée de la coopération et du conflit." Paris 1, 2012. http://www.theses.fr/2012PA010737.
Beau, Noëlle. "Application du maximum de vraisemblance à la comparaison de deux méthodes de dosage biologique : cas des variances inconnues." Paris 11, 1990. http://www.theses.fr/1990PA11P171.
Pradel, Roger. "Estimation et comparaison de probabilités de survie par suivi individuel et utilisation en biologie des populations." Montpellier 2, 1992. http://www.theses.fr/1992MON20152.
Firippi, Eleni. "Analyse mathématique, couplage et contrôle pour modèles d'oscillateurs biologiques synthétiques." Thesis, Université Côte d'Azur, 2020. http://theses.univ-cotedazur.fr/2020COAZ4105.
Biological oscillators are present in most living organisms and play major roles in their development and regulation. Synthetic biology is a rising multidisciplinary field that aims to create new circuits from biomolecular elements, with the goal to better understand the dynamics underlying complex biological systems. Mathematical models play a crucial role in the study and improvement of synthetic gene circuit design, to ensure the desired functionality of the new genetic circuits, as well as to provide predictions on the efficient and robust performance of the implementation. To contribute to the design and analysis of synthetic oscillators, in a first step, we analytically study a two-gene synthetic oscillator, applying both bifurcation analysis and the piecewise affine (PWA) framework, and propose a variant of the model to enhance its oscillatory capacity. In a second step, inspired by circadian rhythms, we study a network of N two-gene synthetic PWA oscillators, and compare the effect of three different coupling topologies on the dynamics and synchronization properties of the network. In a third step, motivated by the interconnection of the cell cycle and circadian clock, we analyze the coupling of the two-gene oscillator with two other synthetic oscillators: the repressilator and a reduced cell cycle model. Two main bidirectional coupling schemes are considered and we perform a "controller-follower" analysis to characterize the capacity of each system to determine or control the period of the coupled system. Based on this analysis, we can identify the coupling schemes admitting a wider range of dynamical responses, as well as suggest strategies for period-control of two coupled oscillators and tunability of a system through the coupling with another system
Motsch, Sébastien. "Modélisation mathématique des déplacements d'animaux et dérivation de modèles macroscopiques." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/841/.
The modeling of animals displacements can occur at two different scales. One may either describes the trajectories of each individual using the so-called individual based models (at a "microscopic" scale), or we can describe the dynamics of the all group with "macroscopic" quantities (density, flux. . . ). In this thesis, we want to connect these two descriptions, the microscopic and the macroscopic scale. Therefore, we can link individual and global dynamics. In a first part, we have introduced a new model for fish displacement called "Persistent Turning Walker" (PTW) based on experimental data. We have given two methods to derive a diffusion equation from this model, a method using tools from functional analysis and a second method using probabilistic tools. The originality of the PTW model mainly relies in the use of curvature to describe individual displacement, this novelty has been used to extend other types of models and to analyse experimental trajectories. In a second part, we have studied the so-called Vicsek model which is an individual based model widespread used in the modeling of animals displacements. We have derived for the first time a macroscopic model from this model (a non-conservative hyperbolic system with a geometric constraint). The numerical simulations of the macroscopic model obtained have shown the relevance of the macroscopic model to describe the microscopic dynamics of the Vicsek model at large scales. Key words : Mathematical biology, Individual based model, Stochastic diffential equation, Kinetic equation, Asymptotic analysis, Diffusion approximation, Hyperbolic systems
Martin, Hugo. "Étude de données et analyse de modèles intégro-différentiels en biologie cellulaire." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS668.
In this dissertation, we are interested in the study of some dynamics in molecular biology, making us of mathematical analysis of established models, modelling and data analysis. The first two chapters focus on growth-fragmentation equations with linear growth rate. We are first interested in the recent so-called incremental model, describing a bacterial population. We prove the existence and uniqueness of the solution of the eigenproblem in a weighted Lebesgue space. Then we study the asymptotic behaviour of measures solutions of the growth-fragmentation equation in the equal mitosis case. A solution is then expressed as a semigroup acting on an initial condition. We extend to this framework a known phenomenon of long time oscillating dynamics, which results here in a weak convergence of the solution towards a periodic family of measures. The third chapter deals with the joint dynamics between mesenchymal, pre-adipocyte and adipocyte cells. We propose a non-linear model in which the growth rate depends on the average size of the latter and analyze it using both analytical and numerical approaches. In the last chapter, we carry out a statistical analysis of experimental data from individual yeast lines. In particular, we highlight the existence of distinct phenomena between early arrests and replicative senescence. Finally, we propose a refinement of an existing model, now able to describe the generation of onset of senescence for all the lineages
Guziolowski, Carito. "Étude des réseaux biologiques à grande échelle par modélisation statique et résolution des contraintes." Rennes 1, 2010. http://www.theses.fr/2010REN1S006.
Il existe plusieurs approches qui modélisent des réseaux de régulation génétiques afin d'élucider la dynamique d'un système biologique. Cependant, ces approches concernent des modèles à petite-échelle. Dans cette thèse nous utilisons un approche formelle sur les réseaux de régulation à grande-échelle qui modélise les variations des concentrations des molécules d'une cellule entre deux états stationnaires. On teste la cohérence entre la topologie du réseau et des données d'expression génétique en utilisant une règle causale de consistance. Les résultats de cette approche sont : test de la consistance entre les données et un réseau, diagnostic des régions du réseau inconsistantes avec les données expérimentales, et inférence des variations des éléments du réseau. Notre méthode raisonne sur la topologie globale du réseau en utilisant des algorithmes efficaces basés sur des diagrammes de décision, des graphes de dépendance, ou la programmation par ensemble réponse. Nous avons proposé des programmes et des outils bioinformatiques basés sur ces algorithmes qui automatisent ces raisonnements. On a validé cette approche en utilisant des réseaux transcriptionnels des espèces E. Coli et S. Cerevisiae, et le réseau de signalisation de l'oncogène EWS-FLI1. Nos résultats principaux sont: (1) un pourcentage élevé de validation des prédictions sur la variation des molécules du réseau, (2) des corrections manuelles et automatiques efficaces du modèle et/ou données, (3) l'inférence automatique des rôles des facteurs de transcription, et (4) raisonnement automatique sur les causes qui influencent des phénotypes importants dans des réseaux de signalisation
Niknahad, Ghar Makher Hamid. "Minéralisation du soufre associée à la décomposition des matières organiques dans les sols et relations avec les dynamiques du carbone et de l'azote." Paris, AgroParisTech, 2008. http://www.theses.fr/2008AGPT0051.
Lê, Cao Kim-Anh. "Outils statistiques pour la sélection de variables et l'intégration de données "omiques"." Toulouse, INSA, 2008. http://eprint.insa-toulouse.fr/archive/00000225/.
Recent advances in biotechnology allow the monitoring of large quantities of biological data of various types, such as genomics, proteomics, metabolomics, phenotypes. . . , that are often characterized by a small number of samples or observations. The aim of this thesis was to develop, or adapt, appropriate statistical methodologies to analyse highly dimensional data, and to present efficient tools to biologists for selecting the most biologically relevant variables. In the first part, we focus on microarray data in a classification framework, and on the selection of discriminative genes. In the second part, in the context of data integration, we focus on the selection of different types of variables with two-block omics data. Firstly, we propose a wrapper method, which agregates two classifiers (CART or SVM) to select discriminative genes for binary or multiclass biological conditions. Secondly, we develop a PLS variant called sparse PLS that adapts l1 penalization and allows for the selection of a subset of variables, which are measured from the same biological samples. Either a regression or canonical analysis frameworks are proposed to answer biological questions correctly. We assess each of the proposed approaches by comparing them to similar methods known in the literature on numerous real data sets. The statistical criteria that we use are often limited by the small number of samples. We always try, therefore, to combine statistical assessments with a thorough biological interpretation of the results. The approaches that we propose are easy to apply and give relevant results that answer the biologists needs
Malgras, Jacques. "Applications, à des données de la biologie des populations et de l'écologie, de méthodes d'analyse des séries temporelles." Lyon 1, 1996. http://www.theses.fr/1996LYO10240.
Chamoun, Georges. "ÉTUDE MATHÉMATIQUE ET NUMÉRIQUE DE MODÈLES EN CHIMIOTAXIE-FLUIDE ET APPLICATIONS À LA BIOLOGIE." Phd thesis, Ecole Centrale de Nantes (ECN), 2014. http://tel.archives-ouvertes.fr/tel-01015918.
Masci, Pierre. "Control and optimization of ecosystems in bioreactors for bioenergy production." Nice, 2010. http://www.theses.fr/2010NICE4064.
Some alternative biofuels, produced by microbial ecosystems, are presently studied with the aim of limiting the unreasoned resource consumption of energetic resources, and greenhouse gases emissions which modify the climate. In this thesis we have considered bioreactors based on oleaginous microalgae, and on anaerobic bacterial ecosystems which degrade wastes and produce methane. The aims of these works were to better understand these processes and to improve their performances. First we have developed and studied models of microalgal cultures in photobioreactors, in which algal pigments cause strong light attenuation. For anaerobic digestion we have used an existing model. By rigorous mathematical analysis of these models, we proposed strategies for optimizing their productivity. Then the study of natural selection between several microbial species, in these two ecosystems, leads to the protection of the species which wins the competition. And finally we showed how it’s possible in each ecosystem to control competition and drive natural selection, in order to advantage species which efficient characteristics, inducing better performances
Voelker, François. "Étude des réversions d'auxotrophie chez une souche de Corynebacterium glutamicum productrice de L-lysine : effets de l'environnement sur les cinétiques de production de révertants et de L-lysine et essai de modélisation." Compiègne, 1996. http://www.theses.fr/1996COMPD868.
Dérédec, Anne. "De la menace à l’outil : modélisation de l’impact du parasitisme en biologie de la conservation." Paris 11, 2005. http://www.theses.fr/2005PA112351.
The current erosion of biodiversity makes crucial the understanding of the mechanisms involved in population decline. As parasites strongly affect the dynamics of their hosts, their impact needs to be accurately modeled. The Allee effect is implicated in numerous extinction events. It shares common characteristics with parasitism that make their combined effect difficult to predict. To analyse the impact of the Allee effect on a host population facing an infection, we built a simple model of ordinary differential equations of type SI. This model highlights that the Allee effect of a host population can protect it from invasion of microparasits. However, if infection succeeds in spreading, the Allee effect increases the detrimental consequences of parasites on theirhosts. In order to protect ecosystems from pest species, a new method is currently under development : virus-vectored immunocontraception. It consists in genetically modifying viruses so that they would sterilize the target species. This method has been theoretically studied only through asexual models, yet it sterilizes only one sex. In order to estimate the error made by neglecting this characteristic when assessing the control success, we built a stochastic individual based model and ran simulations. We show that asexual models generally fail to predict the impact of this method on pest dynamics and highlight the necessity to take account of the mating system of the target species. Considering parasitism in turn as a tool in conservation biology, this work gives rise to some reflection on modelling and highlights the importance of an in-depth knowledge of the biological situations considered
Cregut, David. "Application de la modélisation moléculaire à l'étude stsructurale de la tropomyosine et des annexines : une approche complémentaire de l'expérience." Montpellier 2, 1995. http://www.theses.fr/1995MON20026.
Zulkower, Valentin. "Etude de la dynamique des mécanismes de la répression catabolique : des modèles mathématiques aux données expérimentales." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAM080/document.
Carbon Catabolite Repression (CCR) is a wide-spread mode of regulation in bacteria by which the enzymes necessary for the uptake and utilization of some carbon sources are repressed in presence of a preferred carbon source, e.g., glucose in the case of Escherichia coli . We propose a joint mathematical and experimental approach to separate and evaluate the importance of the different components of CCR. In particular, we show that both cyclic AMP and the global physiology of the cell play a major role in the regulation of the cAMP-dependent genes affected by CCR. We also present methodological improvements for the study of gene regulatory networks in general. In partic- ular, we examine the applicability of the Quasi-Steady-State-Approximation to reduce mathematical gene expression models, and provide robust meth- ods for the robust estimation of growth rate, promoter activity, and protein concentration from noisy kinetic reporter experiments
Lardeux, Frédéric. "Biologie, écologie et dynamique de population de l'éperlan (Osmerus eperlanus, L. ) (poisson, clupéiforme, L. ) dans l'estuaire de la Loire (France)." Brest, 1986. http://www.theses.fr/1986BRES2031.
Taing, Cécile. "Dynamique de concentration dans des équations aux dérivées partielles non locales issues de la biologie." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS077.
This thesis focuses on the dynamics of Dirac mass concentrations in non-local partial differential and integro-differential equations motivated by evolutionary biology. We consider population models structured in phenotypical traits and, taking into account adaptation and mutation phenomena, we aim to describe the selection of the fittest traits in a given environment. The mathematical modeling of these biological problems leads to nonlinear and nonlocal equations, with a small parameter that induces two time-scales. The asymptotic solutions to these equations are population distributions on the traits space and concentrate in Dirac masses located on the dominant traits. In the first part, we study the Dirac mass dynamics in a chemostat model, using a Hamilton-Jacobi formulation. The chemostat model is a system of equations describing the dynamics of consumers and nutrients in a bioreactor. In a second part, we investigate a competition model structured in age and phenotypical traits. By means of an appropriate factorization, we obtain the asymptotic limit of the solution as a decomposition into two profiles, one in age, the other in traits. When mutations are introduced, a Hamilton-Jacobi equation arises and we prove a uniqueness result of the solution to this equation in the framework of viscosity solutions. The last part is devoted to sexual population models. These models under investigation include asymmetric trait heredity or asymmetric trait-dependent fecundity between the parents: each individual inherits mostly its traits from the female
Canu, Stéphane. "La continuation appliquée aux modèles biologiques." Compiègne, 1986. http://www.theses.fr/1986COMPI237.