Dissertations / Theses on the topic 'Échelles biologiques'
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Nguepedja, Nankep Mac jugal. "Modélisation stochastique de systèmes biologiques multi-échelles et inhomogènes en espace." Thesis, Rennes, École normale supérieure, 2018. http://www.theses.fr/2018ENSR0012/document.
The growing needs of precise predictions for complex systems lead to introducing stronger mathematical models, taking into account an increasing number of parameters added to time: space, stochasticity, scales of dynamics. Combining these parameters gives rise to spatial --or spatially inhomogeneous-- multiscale stochastic models. However, such models are difficult to study and their simulation is extremely time consuming, making their use not easy. Still, their analysis has allowed one to develop powerful tools for one scale models, among which are the law of large numbers (LLN) and the central limit theorem (CLT), and, afterward, to derive simpler models and accelrated algorithms. In that deduction process, the so-called hybrid models and algorithms have arisen in the multiscale case, but without any prior rigorous analysis. The question of hybrid approximation then shows up, and its consistency is a particularly important motivation of this PhD thesis.In 2012, criteria for hybrid approximations of some homogeneous regulation gene network models were established by Crudu, Debussche, Muller and Radulescu. The aim of this PhD thesis is to complete their work and generalize it afterward to a spatial framework.We have developed and simplified different models. They all are time continuous pure jump Markov processes. The approach points out the conditions allowing on the the one hand deterministic approximations by solutions of evolution equations of type reaction-advection-diffusion, and, on the other hand, hybrid approximations by hybrid stochastic processes. In the field of biochemical reaction networks, we establish a CLT. It corresponds to a hybrid approximation of a simplified homogeneous model (due to Crudu et al.). Then a LLN is obtained for a spatial model with two time scales. Afterward, a hybrid approximation is established, for a two time-space scales spatial model. Finally, the asymptotic behaviour in large population and long time are respectively presented for a model of cholera epidemic, through a LLN followed by the upper bound for compact sets, in the context of a corresponding large deviation principle (LDP).Interesting future works would be, among others, to study other spatial geometries, to generalize the CLT, to complete the LDP estimates, and to study complex systems from other fields
Trebulle, Pauline. "Modélisation multi-échelles de réseaux biologiques pour l’ingénierie métabolique d'un châssis biotechnologique." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLA022/document.
Metabolism defines the set of biochemical reactions within an organism, allowing it to survive and adapt to different environments. Regulating these reactions requires complex processes involving many effectors interacting together at different scales.Developing models of these regulatory networks is therefore an essential step in better understanding the precise mechanisms governing living systems and ultimately enabling the design of synthetic, self-regulating and adaptive systems at the genome level. As part of this interdisciplinary work, we propose to use an iterative network inference and interrogation approach to guide the engineering of the metabolism of the yeast of industrial interest Yarrowia lipolytica.Based on transcriptomic data, the first network for the regulation of adaptation to nitrogen limitation and lipid production in this yeast was inferred.The interrogation of this network has then allowed to to highlight and experimentally validate the impact of several regulators on lipid accumulation. In order to further explore the relationships between regulation and metabolism, a new method, CoRegFlux, has been proposed for the prediction of metabolic phenotype based on the influence profiles of regulators in the studied conditions. This R package, available on the Bioconductor platform, was then used to better understand adaptation to nitrogen limitation and to identify phenotypes of interest for strain engineering, particularly for the production of lipids and amino acid derivatives such as violacein.Thus, through an iterative approach, this work provides new insights into the interactions between regulation and metabolism in Y. lipolytica, conserved regulatory module in this yeast and contributes to the development of innovative integrative methods for computer-assisted strain design
Puech, Camille. "Hétérogénéité des pratiques agricoles biologiques et conventionnelles dans les paysages bretons : effets sur les communautés d'insectes auxiliaires à différentes échelles." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S117/document.
Due to the loss of biodiversity and increasing food insecurity, modern agriculture must evolve toward a more sustainable management of agricultural landscapes. Organic Farming (OF) is considered as a promising solution to meet this challenge. Organic practices are indeed generally more favorable to pest natural enemies than Conventional Farming (CF), suggesting that pesticides could be replaced by biological control. However, studies evaluating these effects are contradictory, probably because they do not consider the diversity of practices implemented in OF and CF. On a broader scale, practices have rarely been considered in the description of landscape heterogeneity, although the nature and configuration of farmland must affect species. The target of this PhD work is to evaluate the effects of the diversity and spatial organization of organic and conventional farming practices on insect natural enemies, at field and landscape scales. A fieldwork was conducted in 2012 and 2013 in Brittany. Forty pairs of organic and conventional winter wheat fields were selected, distributed along a landscape gradient of OF area. In each field, aphid natural enemies (ladybirds, carabid beetles, parasitoids) were sampled. We interviewed farmers to characterize farming practices implemented in fields and their surrounding landscape. We observed a wide diversity of farming practices in OF and CF. At field scale, effects of practices on the diversity of natural enemies were strong, OF being overall more favorable. Considering a finer description of practices allowed us identifying those really affecting insects, and showing they can be enhanced regardless of the farming type. At landscape scale, we found no effect of the OF area and configuration on natural enemies. With a more detailed description of practices, we however highlighted the importance of some farming strategies, at some scales. Based on these results, we open up avenues to manage agricultural landscapes. Methodological issues related to the description of farming practices on large areas are also discussed
Blanck, Aurélie. "Variabilité des traits d'histoire de vie de poissons d'eau douce Européens à différentes échelles spatiales et niveaux biologiques : (population et espèce)." Lyon 1, 2007. http://www.theses.fr/2007LYO10071.
The objective of improving understanding of life-history traits of organisms and their variation is recurrent in ecology. It is now widely accepted that environmental constraints in freshwaters play a key role in life-history trait variations in fish. In this context, this work aims to study the relationships between life-history traits of European freshwater fish and their environment focusing on different biological levels (population and species) and different spatial scales (continental, regional and local scales). Using biological and environmental data from published sources at the European scale and from field work in the Rhone river basin, this work illustrates (1) the effect of temperature at the continental and regional scales on several population traits, that are not confirmed for all species and (2) the weak effect of hydraulics at the continental and regional scales on population traits. By contrast, this work identifies more important relationships between hydraulics and traits than between temperature and traits at the species level. Microhabitat hydraulics seems to provide a template for species ecological strategies with fast-flowing and shallow microhabitats (riffles) selecting opportunistic species. The comparison between the intraspecific variation in traits and the interspecific variation in traits illustrates the relevance of using traits estimated at the species level and at the regional scale, and traits such as fecundity and traits associated with body size estimated at the species level from literature, in interspecific and inter-communities comparative approaches. By integrating variation of multiple traits in different biological levels and at different spatial scales, my thesis provides interesting elements for ecologists of different disciplines such as population biology and dynamics, species biology, community ecology and evolutionary ecology
Grulois, Daphné. "Etude de la dispersion et du recrutement à différentes échelles spatiales chez Undaria pinnatifida, une macro-algue introduite le long des côtes bretonnes." Paris 6, 2010. http://hal.upmc.fr/tel-01111061.
Weil, Sarah Sophie. "Le rôle des traits des espèces dans la dispersion à différentes échelles - de la compréhension du passé profond aux processus actuels." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. https://thares.univ-grenoble-alpes.fr/2023GRALV030.pdf.
A pressing challenge in ecology is to unravel the mechanisms that underlie the distribution of life at a global scale. Rare dispersal events across biogeographic barriers and establishment in new regions are central to this: these events determine the distribution of both the dispersing species and of species in the receiving community, and they can open opportunities for speciation. On smaller scales, dispersal is integral to species’ persistence, allowing them to respond to changes in their environment directly through movement or indirectly through adaptation. Not all species have the same ability to disperse and establish. Better understanding these differences has gained new urgency today if we are to accurately assess risks, challenges and conservation opportunities in the context of biological invasions, land-use and climate change. Species’ traits are thought to be an important factor in successful dispersal. For example, large species are often better dispersers than small species, and plants with seeds that can float are more likely to disperse over island archipelagos than those with seeds that sink. However, there have been few tests of theory on how species traits might support dispersal at large biogeographic scales. In this thesis, I combine biogeographic, macroecological and macroevolutionary approaches to identify the role of body size and life-history traits in dispersal, and to test the transferability of trait-dispersal relationships across scales. First, I quantify and compare the role of traits in biogeographic histories of 56 tetrapod clades. Second, I discuss in a conceptual synthesis if and how information from macroevolutionary and biogeographic studies can be used to better understand species present-day biological invasions, as well as present-day extinction risk due to changing environmental conditions. Third, I test conceptual considerations from this work on empirical data, linking the patterns observed in past biogeographic dispersal to present-day biological invasions and range shifts. Together these three strands highlight the importance of taxonomic, geographical and temporal contexts in the role of species traits in dispersal, which is an important step forward to better predictions of species’ abilities to respond to changing environmental conditions
Vallet, Jeanne. "Gradient d'urbanisation et communautés végétales d'espaces boisésApproche à plusieurs échelles dans trois agglomérations du Massif armoricain." Phd thesis, Université d'Angers, 2009. http://tel.archives-ouvertes.fr/tel-00409694.
Vallet, Jeanne. "Gradient d'urbanisation et communautés végétales d'espaces boisés : Approche à plusieurs échelles dans trois agglomérations du Massif armoricain." Phd thesis, Université d'Angers, 2009. http://tel.archives-ouvertes.fr/tel-00464972.
Kohler, Sophie. "Contribution au développement et à la dosimétrie multi-échelles de dispositifs pour l’exposition de cellules biologiques à des impulsions électriques nanosecondes et subnanosecondes de haute intensité." Limoges, 2013. http://aurore.unilim.fr/theses/nxfile/default/e4cb8901-5864-474c-9cc5-9b5baced9a6a/blobholder:0/2013LIMO4021.pdf.
For sufficiently high intensities, in vitro experimental studies have shown that the biological effects of microsecond pulses are located at the plasma membrane, while those of nanosecond pulses may as well occur at intracellular membranes. The biophysical mecanisms underlying the observed biological effects are not yet clear. In addition, numerical studies have suggested that electric pulses with subnanosecond duration may be able to trigger biological effects directly inside the intracellular organelles. In this work, we propose and study an in vitro exposure system as well as experimental and numerical dosimetry techniques with the purpose of investigating the effects of intense nanosecond and subnanosecond pulsed electric fields. We show the ability of a novel generator based on a coaxial structure to produce the expected pulses. We then propose the use of transverse electromagnetic (TEM) cells to deliver the pulses to biological cells contained in a plastic dish. An electro-optic probe is characterized and validated for macrodosimetric measurements inside the cell culture medium. We also show that the TEM cell-based setup is adapted for intracellular measurements using microfluorimetry techniques. Lastly, we report a numerical tool for dosimetric studies at atomic scale. The method that has been developed combines results of molecular dynamics simulations to a quasi-electrostatic approach using a 3D finite-difference-method code
Nguyen, Nhi Gia Vinh. "Conception de modèles multi-échelles pour l’aide à la décision environnementale : application au contrôle des invasions de cicadelles brunes dans le Delta du Mékong (Vietnam)." Paris 6, 2013. http://www.theses.fr/2013PA066472.
In South-East Asia, the problem of controlling the invasions of rice pests is a major economical problem, which is tackled by multiple scientific disciplines and is dealt with by several decisional scales. This PhD thesis contribute to the researches undertaken since 40 years on the eradication (or at least the control) of the rice pest named Brown plant hopper (BPH) by proposing a design methodology of dynamically scaling models as a foundation for decision support systems dedicated to the assessment of regional and local control policies. It has been applied to and validated on different scenarios of BPH migrations in the Vietnamese Mekong Delta, where four different geographical and political levels have been coupled in the same framework (village, commune, province, and region), each of them represented with its own dynamics (social, biological, ecological ones) but also with its relationships with the other levels. The main contribution of this research is an agent-based multi-level modeling system that allows modelers to simulate and evaluate different control policies against invasions of the Brown plant hoppers at different scales of time and space. This system couples and organizes several sub-models with separate functions: growth and migration models of BPH that take ecological and environmental processes into account at different spatial and temporal scales, social models of the various stakeholders (from farmers to political deciders), models dedicated to the up- and downscaling processes occurring between the levels of representation
Surget, Gwladys. "Processus adaptatifs des végétaux marins face au changement climatique à différentes échelles de temps et d'espace : dynamique de populations, métabolomique, écophysiologie et potentiels de valorisation." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0056/document.
Three model species with a large distribution along European coasts, along a latitudinal gradient from Norway to Portugal was chosen: Sargassum muticum, Codium fragile and Gracilaria vermiculophylla. The aims of this PhD thesis were to study the phenology, ecophysiology and the metabolom of these non-native marine macrophytes and their ability to cope with a variation of environmental factors 1) at a population scale, 2) along the latitudinal gradient (in relation with the global climatic change) and to propose 3) bio-inspired molecules for industrial purposes. The latitudinal gradient corresponding to a thermic gradient, allows to imitate the global warming as climatic change ¡mpacts are most of the time only visible at decennial scale.Monitorings of ecology, metabolome and potential impacts of these macroalgae, at a population scale, allowed to study the development and life cycle of these models. In particular, G. vermiculophylla exhibited a specific phenology (with a majority of small vegetative fragments, <3cm) in the Bay of Brest and a highly tolerance to burial until 12 cm depth in the sediment by acclimatizing its metabolome together with the ability to maintain a dormancy physiology. This engineer species modifies deeply muddy shores of this Bay. Latitunal gradients's monitoring highlighted the phenological plasticity and a contrasted invasive potential of C.fragile between latitudes. During low spring tides, species exhibited an acclimation of their photophysiology between latitudes with photoinhibition process related to induce environmental stress. Furthermore, this work showed the multifunctional properties of polyphenols enriched extracts with antioxidant, photoprotective or osteogenic activities, highlighting the emergence of original bio-inspired pathways for cosmetic or biomaterial applications
Rocca, Alexandre. "Formal methods for modelling and validation of biological models." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAM028/document.
The purpose of this thesis is the modelling and analysis of biological systems with mechanistic models (in opposition with black-box models).In particular we use two mathematical formalisms for mechanism modelling: hybrid dynamical systems and polynomial Ordinary Differential Equations (ODEs).Biological systems modelling give rise to numerous problem and in this work we address three of them.First, the parameters in the differential equations are often uncertain or unknown.Consequently, we aim at generating a subset of valid parameter sets such that the models satisfy constraints deducted from some experimental data.This problem is addressed in the literature under the denomination of parameter synthesis, parameter estimation, parameter fitting, or parameter identification following the context.Then, if no valid parameter is found, one solution is to revise the model. This can be done by substituting a law in place of a constant parameter.In the literature, models with uncertain parts are known as grey models, and their studies can be found under the term of model identification.Finally, it may be necessary to ensure the correctness of the built models using validation, or verification, methods for a continuous over-approximation of the determined valid parameters.In this thesis we study the parameter synthesis problem, in the Haemoglobin production model case study, using an adaptation of the classical method based on Monte-Carlo sampling, and numerical simulations.To perform model revision of hybrid dynamical systems we propose an iterative scheme of an optimal control method based on occupation measures, and convex relaxations.Finally, we assess the quality of a model using set-based simulations, and reachability analysis.For this purpose, we propose two methods: the first one, which relies on Bernstein expansion, is an extension for hybrid dynamical systems of the reachability tool sapo , while the other uses Krivine-Stengle representations to perform the reachability analysis of polynomial ODEs.We also provide a methodology to generate hybrid dynamical systems modelling biological experimental protocols.All of these proposed methods were applied in different case studies.We first propose a model of haemoglobin production during the differentiation of an erythrocyte in the bone marrow.To develop this model we first applied the Monte-Carlo based parameters synthesis, followed by the model revision to correctly fit to the experimental data.We also propose a hybrid model of Cadmium flux in rats in the context of an experimental protocol, as well as a preliminary study of the effect of low dose Cadmium on a Glucose response.Finally, we apply the reachability analysis techniques for the validation on large parameters set of the iron homoeostasis model developed by Nicolas Mobilia during his Phd.We note the haemoglobin production model, as well as the glucose reponse model can be formalised, in their experimental context, as hybrid dynamical systems. Thus, they serve as proof of concept for the methodology of biological experimental protocols modelling
Marchadour, Charlotte. "Spectroscopie RMN cérébrale pour l’étude du milieu intracellulaire in vivo : développements méthodologiques pour la diffusion à courtes échelles de temps et pour la mesure du pH en détection 31P." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112111/document.
NMR spectroscopy is a unique modality to evaluate intracellular environment in vivo. Indeed observed molecules are specifically intracellular and generally have a biochemistry role and a specific cellular compartmentation. That could be a useful tool to understand cell functioning in their environment. My thesis work consisted in development of new sequence in both diffusion and phosphorus NMR spectroscopy.My first study was to develop a diffusion-weighted spectroscopy at ultra-short diffusion time to look at the anomalous diffusion in the rat brain. ADC evolution as a function of time shows that brain metabolites motion is mainly due to random diffusion and that active transport (if exist) are negligible. Data modeling evidences that diffusion at short diffusion time is sensitive to cytoplasm viscosity and short scale crowding. In collaboration with the pharmaceutical company, this technique was chosen to follow up transgenic mice (rTg4510), model of tau pathology. Preliminary results show significant differences of ADC at an early stage of neurodegenerescence (3 and 6 months).Phosphorus spectroscopy allows observation of metabolites directly implicated in energetic processes. During this thesis, localization sequences were developed to measure intracellular pH in the primate striatum. These sequences are supposed to be used to evaluate the potential of pH as a biomarker of neurodegenerescence in a phenotypic model of the Huntington disease in the non-human primate
Boyé, Aurélien. "Diversité taxinomique et fonctionnelle des habitats benthiques dans l'espace et dans le temps : une perspective régionale et décennale Constancy despite variability: Local and regional macrofaunal diversity in intertidal seagrass beds ?, in Journal of Sea Research 130, December 2017." Thesis, Brest, 2018. http://www.theses.fr/2018BRES0110.
This thesis takes advantage of long-term monitoring data covering a regional scale to better apprehend the maindrivers of the diversity of coastal seafloors. Through consideration of multiple spatial and temporal scales and different facets o fcommunity diversity, the main objective of this work was to provide a better predictive understanding of the responses of benthic communities to environmental changes. In particular, this thesis addressed the potential consequences of the on-going homogenisation of the seafloor and the global loss of biogenic habitats, havens of diversity made by foundation species. Through comparison of two such habitats, intertidal seagrass meadows and subtidal maerl beds, with bare sediment devoid of foundationspecies, this thesis has highlighted the key role of biogenicstructures for long-term maintenance of the diversity andfunctioning of benthic communities. Indeed, these habitats mediate the dynamics and responses of benthic communities to environmental conditions, ensure a greater stability of their spatial structures at regional scale, and appeared essential for the long-term maintenance of the ecological functions benthic invertebrates are associated with. This work also highlighted that foundation species may affect benthic communities through different mechanisms, and that has implications on the structure and vulnerability of these communities. Lastly, this the sisemphasized a strong spatial and temporal stability of community richness despite important underlying changes in composition and there by stressed the need to better characterise these compositional variations to guide conservation. These variations contributed, for instance, to an unexpectedly high taxonomic and functional richness of bare sediment at regional scale,similar to those of biogenic habitats, despite being locally depauperate. Overall, broad-scale monitoring programs are fundamental assets to bridge local empirical and theoretical ecological knowledge to the broader scales at which society manage and benefits from natural ecosystems
Louvet, Benjamin. "Automates cellulaires pour la modélisation multi-échelle des systèmes biologiques." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22479/document.
This PhD thesis project is part of a research program in the fields of biology, physics and computer science aiming to propose a simulation approach for performing experiments in silico. For this, we propose to develop a software platform dedicated to multi-scale modeling of biological systems that can be combined with particle physics simulation tools. We also propose a general individual-based model of biological cell in which data obtained from in vitro experiments can be used. We present the development of this platform and the validation process of its functionalities through the implementation of cellular automata from the literature. We then present the design of the biological cell model by giving the hypothesis we made, how we model and how we parameterize the model. Starting from a simple biological system, bacteria, observed in liquid culture, our model uses a multi-scale middle-out approach. We focus on the cell and we model internal processes, assuming that all their properties come from genetic information carried out by the cell’s genome. This model allows to consider the cell behavior, and then to obtain the behavior of a cell population. Data from fluxomic experiments have been used in this model to parameterize the biochemical processes. The results we obtain allow us to consider the model as validated as simulation results match the experimental data
Martinez, Aude. "Modifications N-terminales des protéines : approche multi-échelles et signification biologique." Paris 11, 2010. http://www.theses.fr/2010PA112081.
Co- and post-translational modifications strongly affect proteins final functionality. Among those, the most frequents are early modifications affecting the N-terminus of the protein. This work deals with four such : N-terminal methionine excision (NME), N-myristoylation (MYR), N--acetylation (NAA) and S-palmitoylation. On one side, my work consisted in managing some experimental data for different organisms coming from different kingdoms and elaborating predictive patterns for NME and NAA. On the other side, I performed experiments about MYR with two NMTs originating from the animal and plant kingdom on a 288 peptides set expected to sample the proteome diversity. About 30% were identified as potential MYR substrates. My data reveal specificity differences between the two enzymes. In the end, it was not possible to elaborate a more accurate predictive motif than the one already elaborated. In order to complete this work, I investigated the MYR impact on the subcellular localisation of some of those peptides. It could confirm that efficient MYR as evidenced in vitro induce in vivo localisation of the the protein in the membranes. Those in vivo results reinforce the significance of our in vitro analyse and help understanding myristoylation status of our different peptides. Specificity features of each of those modifications were used to elaborate the predictive platform TermiNator (http://www. Isv. Cnrs-gif. Fr/terminator3/). TermiNator is available for all the scientist community. Any proteome can be annotated for those four N-terminal modifications with this unique tool
Tadrist, Loïc. "Mécanique du feuillage en vent : Approche multi-échelle et conséquences biologiques." Palaiseau, Ecole polytechnique, 2015. https://tel.archives-ouvertes.fr/tel-01115618/document.
A wind gust and the leaves already move. On land, the Beaufort scale is defined through the observation of foliage motion. The leaves motion in wind is the result of fluid-structure interaction between the tree and wind. The effect of wind on the tree is on the one hand static, the leaves reconfigure, change their orientation, and gather themselves, and on the other hand dynamic, when leaves and branches move. Those mechanical effects are explored at the leaf scale, highlighting the effect of the Cauchy number, which scales the aerodynamic efforts and the leaf rigidity, onto the static reconfiguration of leaves, and the effect of reduced velocity, which compares the solid time and the fluid time, onto the trigger of leaf flutter. These results at the leaf scale are broadenned to the whole foliage. Eventually, the models of foliage movement are used to compute global biological traits such as light interception or perceptive effects such as the dynamic motion of the foliage
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
Puillat, Ingrid. "Etude des tourbillons de moyenne échelle du bassin algérien et de leurs conséquences biologiques." Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22107.
Veber, Philippe. "Modélisation grande échelle de réseaux biologiques : vérification par contraintes booléennes de la cohérence des données." Phd thesis, Université Rennes 1, 2007. http://tel.archives-ouvertes.fr/tel-00185895.
Ballutaud, Marine. "L'utilisation d'un cadre de travail mécaniste pour améliorer les outils basés sur les isotopes stables en écologie trophique." Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR058.
The impact of global change on marine ecosystems is unprecedented. In order to preserve ecosystems, trophic metrics are used as indicators of their functioning. Trophic interactions are easily deduced from stable isotopes by inference. However, isotopic inferences are based on the assumption of isotopic equilibrium. This PhD thesis work aims to highlight the need to overcome this assumption by developing dynamic isotope models, thanks to the isotope turnover rate. The approach developed is to build a mechanistic framework via a dynamic model, to create a virtual experiment that allows us to assess the inferences. First, the development of a dynamic mixing model improved the individualdiet estimates, which are biased by 50 % with a static snapshot approach. This bias in diet estimates decreases to 15 % once λ is taken into account, with a static approach integrating isotopic values. For an unbiased and dynamic estimation, the application of the dynamic mixing model is required with an accurate and dynamic estimation of λ. Secondly, the implementation of isotope dynamics to ecosystem models allowed to confirm at the community level, that nitrogen does reflect the average food web structure in a case of opportunistic predation. However, the difference of one trophic level was observed for some top predators, between the estimates by diet matrices and those by nitrogen.The integration of isotope dynamics mechanisms into inferences is a major advance, since it modifies our insight into of trophic interactions in marine ecosystems
Echairi, Abdelwahad. "Effets du cuivre sur quelques indicateurs de la qualité biologique des sols viticoles : étude à différentes échelles." Dijon, 2008. http://www.theses.fr/2008DIJOS008.
Copper-based fungicides are used for more than a century by vine growers to fight against mildew (and other diseases). As a result, copper accumulates in soil, reaching high concentrations, with potential harmful effects on soil biocenosis. In spite of this threat, copper-based products are still in use, especially in organic farming. In this work, we tried to make clear the effects of copper on some aspects of biological quality of vineyards in “real” conditions, on the short, medium and long term. Long term effects were studied in a region (Champagne) through soil samples representing a large range of copper concentrations. Two different sites, in Burgundy and Champagne were used to study the medium-term effects (decade). Finally, to study in details the short term effects (1-4 years) we used an experimental approach, in three different locations, copper additions being the only source of variation. Biological indicators (microbial biomass, C & N mineralization, nitrification) were used for routine analysis. In addition, two fungal populations of interest for vine growing and wine making were studied: mycorrhizal-arbuscular fungi (MA) and yeasts able to grow on vine juice. The main characteristics of the soil samples were measured simultaneously, including total and EDTA-extractable copper. Microbial biomass is a reliable indicator of soil quality but, for low levels of Cu, spatio-temporal variations were higher than the effects of copper addition. The same observations were made for C and N mineralization activities. Nitrification activity (ammonium oxidation) turned out to be less affected by copper additions than by previous nitrogen additions (as reduced forms: organic N and ammonium N). Therefore, nitrification is not a reliable indicator of Cu contamination. Our results also showed that MA fungal populations are of potential interest to assess the effects of cultural practices, including copper additions, provided the other sources of variation are under control. These populations can be characterized both quantitatively (spore numbers) and qualitatively (diversity of morphological types). Significant differences between treatments were observed in our experiments. However, the efficiency of these populations (for P uptake) are not addressed by these tests. Populations of yeasts are also potentially interesting to study the effects of Cu in vineyards. We developed a protocol to assess both genotypic and phenotypic diversity of these fungal populations. Genotypic characterization was based on 18S rDNA PCR-RFLP and polymorphism of D1-D2 region of 26S rDNA. Phenotypic characterization was limited to the assessment of copper tolerance by measuring growth rate on a medium containing increasing Cu concentrations. The results showed no correlation between genotypic and phenotypic characterization. Many strains were able to grow on media containing high concentrations of copper, even when they were isolated from soil samples without previous Cu application
Amblard-Gross, Géraldine. "Bryophytes et biomonitoring des retombées atmosphériques en métaux et éléments traces : caractérisation de la variabilité à différentes échelles d'utilisation." Metz, 2000. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2000/Amblard_Gross.Geraldine.SMZ0029.pdf.
Nguyen, Manh Tu, and Manh Tu Nguyen. "Identification multi-échelle du champ d'élasticité apparent stochastique de microstructures hétérogènes : application à un tissu biologique." Phd thesis, Université Paris-Est, 2013. http://tel.archives-ouvertes.fr/tel-00977384.
Nguyen, Manh Tu. "Identification multi-échelle du champ d'élasticité apparent stochastique de microstructures hétérogènes : application à un tissu biologique." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1135/document.
In the framework of linear elasticity 3D for complex microstructures that cannot be simply described in terms of components such as biological tissues, we propose, in this research work, a methodology for multiscale experimental identification of the apparent elasticity random field of the microstructure at mesoscopic scale using displacement field measurements at macroscopic scale and mesoscopic scale. We can then use this methodology in the case of changing scale to obtain the mechanical properties at macroscale. In this context, the major issue is the experimental identification by solving a statistical inverse problem of the stochastic modeling introduced for the apparent elasticity random field at mesoscale. This experimental identification allows to validate the modeling and makes it useful for existing materials with complex microstructures. This research work is proposed in this context in which experimentation and experimental validation based on simultaneous measurements of field imaging at macroscale and mesoscale are made on the cortical bonemakes it useful for existing materials with complex microstructures. This research work is proposed in this context in which experimentation and experimental validation based on simultaneous measurements of field imaging at macroscale and mesoscale are made on the cortical bone
Hadji, Mohamed. "Contributions à l'étude d'un processeur s'intégrant dans un réseau systolique linéaire dédié à la comparaison des séquences biologiques." Rennes 1, 1995. http://www.theses.fr/1995REN10044.
Yvoz, Séverin. "Analyse multi-échelles des compromis entre services écosystémiques fournis par la flore adventice." Thesis, Bourgogne Franche-Comté, 2021. http://www.theses.fr/2021UBFCK008.
Weeds contribute to the provision of various ecosystem services, negative when linked to their harmfulness (disservices) and positive due to the provision of trophic resources (floral resources, seeds) to pollinators and pest natural enemies (services). In this PhD thesis, we analysed how crop management strategies (coherent crop sequences and associated farming practices) implemented by farmers within a small agricultural landscape modulate the weed contribution to (dis)services provision. We also assessed the relative contribution of field cores and field edges (narrow area between the 1st row of the crop and the boundary) to these services. At the annual scale, we show that crop type highly impacts the (dis)services provision, through an effect on the composition of the weed assemblages, but also on the growth rate of individual weed plants and their probability to reach the flowering and seeding stages. Services are thereby higher and more stable within year in the less competitive crops. Similarly, and despite the small area they cover, field edges play a major role in the provision of services at the field scale because they harbour higher weed abundance and richness with individual plants that contribute more to services than the plants located in field cores. At the pluriannual scale, crop management strategy (and notably the crop sequence), drives the level of (dis)services provision. We observe positive correlations between services and disservices, however we managed to identify weed species which provide, in specific growing conditions (crop type, location in the field), the best (dis)services bundles. By a statistical simulation method focussing on the effect of the crop management strategy assemblage at the studied small landscape scale, we show that scenarii composed of a large number of strategies in even proportions are those that deliver the best compromises. Scenarii in which field size was reduced (and which therefore increased the area of field edges in the landscape) resulted in the increase of both services and disservices provision but a higher temporal stability in the provision of services. These results suggest that crop diversification, in space and time, could be an interesting solution to increase weed contribution to ecosystem services provision, without producing too much disservices
Ben, Hassan Ines. "Analyse multi-échelle de la filtration sur microsive de particules modèles inertes et biologiques : caractérisation in situ du dépôt par microscopie confocale." Phd thesis, INSA de Toulouse, 2014. http://tel.archives-ouvertes.fr/tel-01073549.
Djaffardjy, Marine. "Pipelines d'Analyse Bioinformatiques : solutions offertes par les Systèmes de Workflows, Cadre de représentation et Étude de la Réutilisation." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASG059.
Bioinformatics is a multidisciplinary field that combines biology, computer science, and statistics, aiming to gain a better understanding of living mechanisms. It relies primarily on the analysis of biological data. Major technological improvements, especially sequencing technologies, gave rise to an exponential increase of data, laying out new challenges in data analysis and management.In order to analyze this data, bioinformaticians use pipelines, which chain computational tools and processes. However, the reproducibility crisis in scientific research highlights the necessity of making analyses reproducible and reusable by others.Scientific workflow systems have emerged as a solution to make pipelines more structured, understandable, and reproducible. Workflows describe procedures with multiple coordinated steps involving tasks and their data dependencies. These systems assist bioinformaticians in designing and executing workflows, facilitating their sharing and reuse. In bioinformatics, the most popular workflow systems are Galaxy, Snakemake, and Nextflow.However, the reuse of workflows faces challenges, including the heterogeneity of workflow systems, limited accessibility to workflows, and the need for public workflow databases. Additionally, indexing and developing workflow search engines are necessary to facilitate workflow discovery and reuse.In this study, we developed an analysis method for workflow specifications to extract several representative characteristics from a dataset of workflows. The goal was to propose a standardized representation framework independent of the specification language. Additionally, we selected a set of workflow characteristics and indexed them into a relational database and a structured semantic format. Finally, we established an approach to detect similarity between workflows and between processors, enabling us to observe the reuse practices adopted by workflow developers
Djoudi, El Aziz. "Structuration multi-échelle des communautés d'Arthropodes en agro-écosystèmes." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1B056.
In this study, we got interested in quantifying how local and landscape metrics structure arthropod communities in agro-ecosystems. For that, we used a long-term monitoring design located in ‘Ille-Et-Vilaine’ (Brittany, France), composed by spatially pair-matched fields under organic vs. conventional farming systems. First, we found that landscape heterogeneity, also interacting with farming systems, drives the diversity and abundance of trophic groups for both ground- and vegetation-dwelling arthropods. In a second chapter, we showed the importance of landscape context in shaping assemblages of predatory arthropods, and suggested that mechanisms behind the distribution of individual species strongly differ between spiders and carabids. Lastly, we highlighted the importance of distinguishing between resident (emergent) and mobile (circulating) individuals when assessing the differential role of local vs. landscape factors in community assembly. Overall, our results show a strong and positive effect of organic farming on arthropod populations, assemblages and communities, both at local and landscape scales, as well as in interaction with other landscape metrics. We also highlighted the relevance of using different levels of biological organization, and related response variables, when assessing the structure and functioning of arthropod communities in agroecosystems
Taupier-Letage, Isabelle. "Biodynamique du bassin algérien : estimation de la réponse biologique à certaines structures hydrodynamiques de moyenne échelle par télédétection (AVHRR et CZCS) et mesures in situ." Aix-Marseille 2, 1988. http://www.theses.fr/1988AIX22049.
Chifflet, Marina. "Interprétation par modélisation des processus physiques et biologiques observés à courte échelle de temps sur la colonne d'eau : Application à la mer Ligure en Mai 1995 (Campagne Dynaproc)." Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22064.
Ayata, Sakina-Dorothée. "Importance relative des facteurs hydroclimatiques et des traits d'histoire de vie sur la dispersion larvaire et la connectivité à différentes échelles spatiales (Manche, Golfe Gascogne)." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00517082.
Pottier, Julien. "Structures spatiales et traits biologiques du voisinage de la plante au paysage : le cas des digues restaurées des canaux de dérivation du Rhône." Phd thesis, Grenoble 1, 2008. http://www.theses.fr/2008GRE10061.
The spatial patterning of organisms and the resultant consequences are central questions within the science ofboth pure and applied ecology. Spatial heterogeneity is indeed of primary interest within the field of ecological restoration for both the conception and evaluation of projects. The work that has been developed during this PhD project encompasses a study of spatial patterning set against a background of ecological restoration. The study was carried out with a model study system, within an anthropogenic system: the banks of channels deriving the river Rhône. The links between plant spatial patterns and their biological traits have been analysed in this model system with an underlying aim of understanding their role in both community structuring and functioning within a hierarchical system. This approach is based upon the analysis of spatial patterns &om the plant neighbourhood through to the landscape scale. Ln doing so, this needed to combine concepts and methodological techniques derived &om remote sensing, spatial statistics and functional ecology. The results provided an explanation of the development of spatial pattern of vegetation, at various scales, in interpreting the role ofbiological traits related to endogenous processes and/or plant responses to exogenous factors. A synthesis of the results from this study led to the development of a conceptual model that integrates the role of spatial vegetation pattern, plant traits and their interrelationships in the functioning of plant communities. The results from this work also offer practical management perspectives for the evaluation of restoration projects
Pottier, Julien. "Structures spatiales et traits biologiques du voisinage de la plante au paysage : le cas des digues restaurées des canaux de dérivation du Rhône." Phd thesis, Université Joseph Fourier (Grenoble), 2008. http://tel.archives-ouvertes.fr/tel-00482451.
Pallud, Céline. "Étude multi-échelles du fonctionnement hydrodynamique et microbiologique d'un sol soumis à un apport de solutés : application à l'ammonium et au 2,4-D." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10178.
Barbarin, Marine. "Environnement & espaces portuaires : suivi de la qualité du milieu pour une meilleure compréhension de l’effet de variables environnementales à une échelle spatio-temporelle." Electronic Thesis or Diss., La Rochelle, 2022. http://www.theses.fr/2022LAROS045.
Coastal areas are important interface environments between marine and terrestrial ecosystems and are populated by abundant living communities. Among these coastal areas, the Charente coastline is an area of strong economic activities related, among others, to aquaculture, fishing and tourism, thus requiring a good quality of water and environment. However, this coastal area is under the influence of many contaminants: phytosanitary products, hydrocarbons, heavy metals, etc., of which water is the main vector. In order to preserve the Pertuis, the Marine Natural Park has set up a management plan determining the measures of protection, knowledge, enhancement and sustainable development to be implemented for the next 15 years. The QUALIPERTUIS project aims to combine a phase of laboratory tests and on-site measurements in order to provide a new perspective on the causes of bivalve mortality, as well as to understand more broadly the impact of environmental factors influencing the sanitary state of bivalves in port areas and coastal waters. In partnership with the La Rochelle Marina and Port Atlantique La Rochelle, environmental biomonitoring studies have been set up in port areas and in the Pertuis with three species of bivalve molluscs: the black scallop Mimachlamys varia, the hollow oyster Crassostrea gigas and the blue mussel Mytilus edulis. Seasonal environmental monitoring has been carried out on a total of thirteen study sites, distributed in the port areas and the Pertuis
Zhang, Bo. "Contributions à la microscopie à fluorescence en imagerie biologique : modélisation de la PSF, restauration d'images et détection super-résolutive." Phd thesis, Télécom ParisTech, 2007. http://pastel.archives-ouvertes.fr/pastel-00003273.
Henriques, Justine. "Scale-up d'un procédé continu aérobie à lit fluidisé granulaire pour le traitement des effluents." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0021.
Due to more stringent regulations, wastewater processes need to be more compact and effective. The utilization of aerobic granular sludge conjugates compactness and productivity with the control of the operational. Granulation, which need specific conditions, are mostly operated in batch reactors. To improve the capacity of treatment, this study investigates process conditions for an optimal operation for a continuous reactor working with aerobic granular sludge. First of all, granulation technique is optimized in a laboratory batch reactor (SBR) and results reveal that food to microorganism ratio, shear and selection pressure applied influence pellets’ formation and their properties. Then, this optimized method is successfully scaled-up. After that, the utilization of granules in continuous is studied and this mode increases the reactor capacity while the granular structure is maintained. The utilization of an industrial influent shows reserved results. A commercial software was used to simulate experimental results obtained for a fluidized reactor using pellets. The model, proposed by the software, shows inconsistencies in batch mode. The MBBR model seems more appropriate to simulate continuous mode although the whole pellet is not considered. So, the utilization of aerobic granular sludge in a continuous reactor is a promising technology but further research is needed in the long term operation and its modeling
Ghoussein, Youssra. "Ecologie des plantes aquatiques et amphibies invasives et Télédétection : Application à la Jacinthe d’eau au Liban et à la Jussie en France." Thesis, Rennes, Agrocampus Ouest, 2020. http://www.theses.fr/2020NSARD090.
Invasive aquatic and amphibious plants are a major threat for aquatic ecosystems and wetlands worldwide. Water hyacinth (Eichhornia crassipes) and "the" Jussie – Water primroses (Ludwigia peploides and Ludwigia grandiflora), are two biological models are two biological models that cause ecological, economic and health problems. The study of ecology and biology as well as distribution and distribution is an interdisciplinary study to better know these species in their colonized environments. They invaded two physical environments with different characteristics. In Lebanon, since 2006,the Water hyacinth has invaded the Al Kabir Al Janoubi River over a large part, from the estuary towards the upstream part of the river at the level of the Syrian tributary “Al Arousse”. With the amplification of the problems arising from the colonization of the Al Kabir River Water hyacinth, and in the absence of previous studies, we sought to know its ecology, biology, geographicaldistribution and colonization dynamics. In France, Water primrose has been introduced in the 1830s. Today it invades many rivers and ponds; it now colonizes wetlands with the appearance of a terrestrial form in grasslands, causing a real ecological and economic problem. Given the wealth of studies concerning the ecology and biology of the Water Primrose in France, our mission in this study is to study its distribution and to follow its dynamics in wetlands. To study the distribution of these two invasive species, remote sensing tools have been implemented: hyperspectral and multispectral data, with high and very hi
Lesart, Anne-Cécile. "Modélisation théorique du développement tumoral sous fenêtre dorsale : Vers un outil clinique d'individualisation et d'optimisation de la thérapie." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-01061838.
Paumelle, Martin. "Description multi-dimensionnelle de l'environnement à l'échelle des territoires : contribution pour la recherche de déterminants environnementaux dans l'étiologie des maladies chroniques." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILR050.
Among chronic diseases, Crohn's disease (CD) and end-stage renal disease (ESRD) have a multifactorial etiology that remains partly unknown, with a strong suspicion of an environmental link. The spatial distribution of their incidence has been mapped at the municipal level in Northern France, using two health registers (Epimad and Nephronor). These spatial disparities in incidence serve as the starting point to investigate potential environmental determinants that may be involved in the onset of these diseases.The characterization of the environment and its link to health is often approached in a fragmented manner, focusing on a specific emission source, pollutant, or exposure medium. While these approaches are necessary, they may be limited in comprehending the complexity of the relationship between the environment and health, especially for multifactorial diseases with unknown environmental risk factors. In such cases, it is relevant to prioritize territorial and multidimensional strategies before potentially targeting specific environmental risk factors. In this context, how can multiple open environmental data sources be leveraged to identify territorial determinants of multifactorial diseases?The main objective of this thesis is to offer an integrated description of the environment at the territorial level to inform the etiology of the studied diseases. The strategy involved collecting and reusing open environmental data. This approach identified 24 data sources and generated 113 spatial indicators at the municipal level for four departments. These indicators allow for the characterization of contamination levels in various media (air, water, soil), pollutant emissions, the location of emission sources, land use, agricultural practices, the natural features of territories, and climate. Several methodologies were used to exploit these indicators and characterize the environment from a multidimensional perspective.A first approach involved developing composite spatial indices. These indices synthesize information from many indicators into a single global measure. Initially, vulnerability and resilience indices were calculated. They characterize the uneven spatial distribution of environmental determinants that have a beneficial or detrimental impact on health. Subsequently, composite indices of multi-media contamination (air, water, soil) were constructed.A second approach was developed using multivariate classification methods to create territorial typologies and describe the environmental profiles of municipalities. These results provide a more complex view of territories and have allowed to understand how environmental pressures are distributed in space and overlap with each other.Finally, the results of these multidimensional approaches were linked to spatial variations in the incidence of chronic diseases, suggesting potential connections between the environment and the occurrence of these pathologies. For ES-CKD, associations were observed with urban pressure and fine particulate air pollution, corroborating existing literature. For CD, links were suggested with agricultural practices, the natural characteristics of territories, and metallic soil pollution. Further epidemiological approaches are now needed to test these hypotheses and advance research in this area
Sala, Lorenzo. "Modélisation mathématique et simulation de flux sanguins oculaires et leur interactions." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAD021.
Optic neuropathies such as glaucoma are often late-onset, progressive and incurable diseases. Despite the recent progress in clinical research, there are still numerous open questions regarding the etiology of these disorders and their pathophysiology. Furthermore, data on ocular posterior tissues are difficult to estimate noninvasively and their clinical interpretation remains challenging due to the interaction among multiple factors that are not easily isolated. The recent use of mathematical models applied to biomedical problems has helped unveiling complex mechanisms of the human physiology. In this very compelling context, our contribution is devoted to designing a mathematical and computational model coupling tissue perfusion and biomechanics within the human eye. In this thesis we have developed a patient-specific Ocular Mathematical Virtual Simulator (OMVS), which is able to disentangle multiscale and multiphysics factors in a accessible environment by employing advanced and innovative mathematical models and numerical methods. Moreover, the proposed framework may serve as a complementary method for data analysis and visualization for clinical and experimental research, and a training application for educational purposes
Cyr, Frédéric. "Les impacts de la dispersion historique sur la variabilité génétique à différentes échelles spatiales : connaître l'histoire pour mieux comprendre le présent." Thèse, 2012. http://hdl.handle.net/1866/9763.
Current genetic variability depends on a complex combination of historical and contemporary factors. Therefore, an unbiased interpretation of the impact of current processes requires a deep understanding of historical processes that shaped genetic variability. Based on the premise that spatially close populations should share a common recent history, many studies conducted at small spatial scale do not take into account the effect of historical processes. This thesis aims to verify the validity of this assumption by estimating the effect of historical dispersion at large and small spatial scales. The aim of the first part of this thesis was to evaluate the impact of the historical dispersion on the distribution of organisms, at large spatial scale. The freshwater mussels of the genus Floater (Pyganodon spp.) were used as biological model. The dispersal of freshwater mussels occurs when larvae parasitize fish. Also, a series of null models has been developed to evaluate the co-occurrence between parasites and their hosts. The distinct associations of the Newfoundland floater (P. fragilis) with euryhaline fish species can explain its distribution. These associations also promoted differentiation with its sister taxon: the Eastern floater (P. cataracta). This study demonstrated the effects of historical biological associations on the current distribution of species at a large spatial scale. The aim of the second part of this thesis was to evaluate the impact of historical dispersal on the genetic variability, at small spatial scale. This time populations of rock bass (Ambloplites rupestris) and sunfish (Lepomis gibbosus) in adjacent drainages were used as biological model. The striking differences observed between the two species suggest opposing colonization patterns. Rock bass have colonized the drainage from a downstream source, resulting in low genetic diversity upstream and a strong differentiation between drainages. However, the sunfish have colonized the system from upstream, resulting in a high genetic diversity and low differentiation upstream, inducing at the same time a false signal of gene flow between drainages. The present study shows that the historical dispersion may hinder the ability to estimate the actual connectivity at small spatial scale, thus invalidating the premise tested in this thesis. The impacts of historical processes on genetic variability are not easy to demonstrate. The aim of the third part of this thesis was to develop a method to facilitate their detection. The proposed method is very flexible and facilitates the comparison between genetic variability and multiple dispersal hypotheses. The method could be used to compare dispersal hypotheses based on the historic or the current landscape and allow the assessment of historical and contemporary processes on genetic variability. The performances of the method are presented in several simulation scenarios, of increasing complexity. Despite an overall impact of differentiation, the number of individuals or the number of loci sampled, the method is highly effective. To illustrate the potential of the method, two contrasted data sets from previously published studies, were re-analyzed. This thesis demonstrates the impacts of historical dispersal on genetic variability at different spatial scales. Potential historical effects must be taken into account before assessing the impacts of ecological processes on genetic variability. In short, we must bridge the gap between ecology and evolution.