ED Sciences Chimiques
Singlet oxygen-controlled catalysts : conception, synthesis and properties
by Mattéo CAYLA (Institut des Sciences Moléculaires)
The defense will take place at 14h00 - 3N24 Bâtiment A12, Université de Bordeaux, 351 Cr de la Libération, 33405 Talence
in front of the jury composed of
- Brigitte BIBAL - Professeure des universités - Université de Bordeaux - Directeur de these
- Karinne MIQUEU - Directrice de recherche - Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - Université de Pau et des Pays de l'Adour - Rapporteur
- Damien BONNE - Professeur des universités - Institut des Sciences Moléculaires de marseille iSm2 - Université Aix Marseille - Rapporteur
- Yann FERRAND - Directeur de recherche - Institut Européen de Chimie et Biologie - Université de Bordeaux - Examinateur
- Guy ROYAL - Professeur des universités - Université Grenoble Alpes - Examinateur
- Alain FRITSCH - Professeur des universités - Université de Bordeaux - CoDirecteur de these
Switchable catalysis aims to control catalytic activity by modulating the system's behavior in a reversible manner. The known stimuli that regulate artificial catalytic systems are chemical (molecules, ions), physical (temperature, light) or electrochemical (redox). These control tools have been implemented in many switchable units with different specificities. To broaden the field of applications of switchable catalysis, an innovative strategy would consist in introducing a new stimulus that induces unprecedented modulations. This doctoral work aimed to show that catalysis can be modulated by singlet oxygen. Its use in [4+2] cycloaddition with flat 9,10-diphenylanthracene derivatives allows the quantitative formation of the corresponding endoperoxides. The concave geometry of the latter allowed by the peroxo bridge offers a new tridimensional environment to activate the substrate compared to the initial anthracene-based compound. A new family of modular catalysts have been designed from BINOL (1,1'-bi-2-naphtol) based chiral phosphoric acids, substituted by anthracene moieties. The cycloaddition reaction of singlet oxygen onto these derivatives was optimized to efficiently obtain molecules whose geometry and nature of the catalytic site are modified. The catalytic properties of the anthracene- and endoperoxide-based architectures were evaluated using three model reactions (oxetane desymmetrization, aza-Friedel-Crafts and 2-naphtol derivatives dearomatization). These reactions were then studied by molecular modelling to obtain more details about the catalytic activity of these new catalysts. The obtained results are an initial base for the proof of concept for the interest in the new catalysts, despite the chemical complexity of the endoperoxide chiral phosphoric acids. Modelling of the reactions brought a more detailed comprehension of these compounds and their activity, and of possible improvements on catalysts structures and optimization of catalysed reactions.
Magnetic chromium-pyrazine materials: from layered ferrimagnets to their molecular analogues
by Vincent NADURATA (Centre de Recherche Paul Pascal)
The defense will take place at 10h00 - Amphithéâtre Centre de Recherche Paul Pascal 115 Avenue du Dr Albert Schweitzer, 33600 Bordeaux, France
in front of the jury composed of
- Rodolphe CLERAC - Directeur de recherche - Université de Bordeaux - Directeur de these
- Dawid PINKOWICZ - Professeur des universités - Jagiellonian University - Rapporteur
- Corine MATHONIERE - Professeure des universités - Université de Bordeaux - CoDirecteur de these
- Stergios PILIGKOS - Professeur des universités - University of Copenhagen - Rapporteur
- Eric COLLET - Professeure des universités - Université de Rennes - Examinateur
- Cécile ZAKRI - Professeure des universités - Université de Bordeaux - Examinateur
The use of redox-active ligands in coordination chemistry has led to a multitude of materials with exceptional magnetic and electronic properties. In the pursuit of lightweight, multifunctional molecule-based magnets, the redox-active pyrazine has emerged as an excellent bridging ligand candidate due to its ability to facilitate strong magnetic exchange between metal centres. In this thesis, we study the magnetic exchange in chromium-pyrazine materials. First, Chapter 1 lays a context for this work, while Chapter 2 develops a theoretical toolbox for the electronic characterisation of the materials presented in the following. Three experimental chapters present the major findings of this work. In a series of layered ferrimagnets, we show that the interlayer magnetic interactions can be tuned by varying the quantity and nature of the intercalated species, leading to a modulation of the coercive field and ordering temperature (Chapter 3). Post-synthetic modification of such materials can lead to even more dramatic changes in the magnetic properties: conversion from a hard to a soft magnetic phase is induced by axial ligand coordination to square-planar chromium (Chapter 4). Finally, the molecular origins of strong magnetic exchange and electronic delocalisation are probed in a miniaturised molecular analogue bearing a single chromium-pyrazine-chromium bridge (Chapter 5). Chapter 6 ties these results together and explores the many avenues which future investigations based on this work may take.
ED Sciences de la Vie et de la Santé
Islet cell-types and functional networks in nutrient handling: Analyses using novel models and development of microfluidic electrophysiology
by Marie LALLOUET (Institut de Chimie & de Biologie des Membranes & des Nano-objets)
The defense will take place at 14h00 - ithéâtre LaBRI Domaine universitaire, 351, cours de la Libération, 33405 Talence, A30
in front of the jury composed of
- Jochen LANG - Professeur des universités - Université de Bordeaux - Directeur de these
- Magalie RAVIER - Chargée de recherche - INSERM 661, Institut de Génomique Fonctionnelle - Rapporteur
- Jonas JEAN-CHRISTOPHE - Professeur - Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain - Rapporteur
- Agnès NADJAR - Professeur - Neurcentre Magendie - Examinateur
- Isabelle DUPIN - Professeur - Centre de recherche Cardio-Thoracique de Bordeaux, INSERM U1045 - Examinateur
- Raphael SCHARFMANN - Directeur de recherche - Institut Cochin, INSERM - Examinateur
Pancreatic islets play a central role in nutritional homeostasis and are at the heart of diabetes-related mechanisms. This micro-organ consists of several distinct cell types: alpha cells, which secrete glucagon; beta cells, which secrete insulin; delta cells, which secrete somatostatin; and gamma cells, which secrete pancreatic polypeptide (PPY). The activity of the islets depends on interactions between these different cell types, although the precise contribution of some, such as delta and gamma cells, remains poorly understood. Furthermore, there is therapeutic potential in the mechanisms of cell interconversion within the islets. This interdisciplinary project aims to explore the role of these cells through: 1) innovative genetic mouse models to ablate certain hormones or cell types, human pseudo-islets of defined composition, as well as interconverted cells (University of Geneva); 2) the use of microfluidic electrophysiology for short- and long-term monitoring (CBMN). This work will lead to the development of a new physiological model of pancreatic islets, applicable both to mice and humans in silico, with direct implications for the development of new therapies.
New experimental approaches to better understand and diagnose oculocutaneous albinism.
by Vincent MICHAUD (Maladies Rares : Génétique et Métabolisme)
The defense will take place at 14h00 - Salle de Conférence IBGC CNRS UMR5095 1 rue Camille Saint-Saëns CS 61390 33077 BORDEAUX cedex
in front of the jury composed of
- Sophie JAVERZAT - Professeure des universités - Université de Bordeaux - Directeur de these
- Jean MULLER - Maître de conférences - praticien hospitalier - Université de Strasbourg - Rapporteur
- Nicolas CHASSAING - Maître de conférences - praticien hospitalier - Université de Toulouse - Examinateur
- Juliette MAZEREEUW-HAUTIER - Professeur des universités - praticien hospitalier - Université de Toulouse - Rapporteur
Albinism is a group of clinically heterogeneous genetic disorders. Ophthalmologic features are constant including nystagmus, foveal hypoplasia and chiasmal misrouting. Cutaneous features are more variable with hypopigmentation of the skin, hair, and iris. In affected patients, hypopigmentation results directly from a defect in melanin synthesis in skin melanocytes. Ophthalmologic features are due to a signaling defect between the retinal pigmented epithelium and the neuronal retina during development. To date, twenty genes have been identified, defining twenty types of albinism, classified into three forms: oculocutaneous, ocular, or syndromic. Sequencing of these twenty genes confirms the diagnosis in 70% of cases, leaving a significant number of patients without genetic determinism. Among these, patients may bear one or two variants of unknown significance (VUS). This study focuses on 5 major genes which cause autosomal recessive oculocutaneous albinism: TYR, TYRP1, DCT, OCA2 and SLC45A2. The five corresponding proteins have a specific role in melanin synthesis either as a melanogenic enzyme (TYR, TYRP1 and DCT) or as a melanosomal pH regulator (OCA2, SLC45A2). Their precise functions in a given context (species, cell type, developmental stage) remain poorly documented. The first objective of this work is to improve the diagnosis of patients with albinism by multiple approaches of cohort analysis, functional tests and rescue test of VUS. The second objective is the design of melanocyte cell models knock-out (KO) for the 5 genes in order to study their molecular and pigmentary phenotype. First, we report the statistical analysis of a cohort of patients carrying two frequent missense variants in TYR gene classified as VUS. This study shows that the combination of these two missense variants is pathogenic if included in a haplotype with a promoter variant which has important implications in diagnosis strategies. Then we present solid strategies to characterize synonymous and missense variants of OCA2 gene classified as VUS. These analyses prove the pathogenic effect of these variants by increasing skipping of exon 10 of OCA2 gene. We also show that splicing anomalies can be detected from a simple blood sample. In order to increase knowledge on the role of each of the proteins encoded by the five genes of interest (TYR, OCA2, TYRP1, SLC45A2 and DCT), we designed MNT1 melanocyte cell models that are each KO for one of the 5 genes using the CRISPR-Cas9 system. We compare these 5 models by different analyses to assess their melanin production capacity and their molecular characteristics. A comparative proteomic assay allows us to reveal the common and specific regulations between these genes. Finally, the KO model for TYR is used in a rescue test to assess pathogenicity of TYR VUS. This test shows us that missense variants can be reclassified as benign or pathogenic depending on their ability to restore the pigmentary phenotype in this model. Analysis of these cellular models provides new knowledge on melanin biosynthesis physiology. The techniques developed for the analysis of variants will be transferred in a hospital setting to significantly improve diagnosis.
Endothelial cell-induced macrophage efferocytosis alterations: analysis of the mechanisms andtherapeutic approach to correct vasculopathy and fibrosis in systemic sclerosis
by Agathe DEPAIRE (Immunologie Conceptuelle, Expérimentale et Translationnelle)
The defense will take place at 14h00 - Amphithéâtre Bâtiment BBS Amphithéâtre - Bâtiment Bordeaux Biologie Santé, Université de Bordeaux Site de Carreire, 2 Rue Dr Hoffmann Martinot, 33076 Bordeaux Cedex
in front of the jury composed of
- Yves DELNESTE - Directeur de recherche - Université de Nantes-Angers - Rapporteur
- Laurence MICHEL - Chargée de recherche - Université de Paris - Rapporteur
- Valérie LECUREUR - Professeure des universités - Université de Rennes - Examinateur
- Thierry MARTIN - Professeur des universités - praticien hospitalier - Hopitaux Universitaires de Strasbourg - Examinateur
Systemic sclerosis (SSc) is an incurable chronic fibrotic autoimmune disease. The concept of unresolved tissue repair, leading to persistent fibrosis, has emerged based on chronic sterile inflammation, which transforms a controlled repair response into pathological fibrosis. Effective inflammation resolution relies on macrophages' (Mϕ) efferocytosis, the clearance of apoptotic cells. Recently, my team demonstrated the role of IL-1β-stimulated cutaneous microvascular endothelial cells (MVEC) in modulating macrophage polarization towards a mixed M1/M2 inflammatory profile, implicating this process in cutaneous sclerodermic fibrosis. Transcriptomic analysis from skin biopsies highlighted a gene signature associated with reduced efferocytosis in SSc patients compared to controls. This study aimed, through in vitro analyses of purified cells from SSc patients' or healthy donors' skin, to determine whether MVEC and IL-1β contribute to efferocytosis alteration during SSc and evaluate the consequences on fibroblast activation and endothelial-mesenchymal transition (EMT). Monocyte-derived macrophages were generated in the presence of supernatant from MVEC either activated (MVECIL-1β-Mϕ) or not (MVEC-Mϕ) by IL-1β. Our results show a significant reduction in the phagocytosis of apoptotic Jurkat cells (apoJK) by MVECIL-1β-Mϕ, associated with decreased expression of certain direct or indirect receptors involved in efferocytosis. Conversely, adding IL-1β during MDM0 (positive control for phagocytosis) differentiation did not alter their overall efferocytic profile, suggesting that IL-1β's inhibitory effect manifests only in the presence of the endothelial secretome. We then studied the effects of post-efferocytosis macrophage secretome on fibroblast activation and EMT. MVECIL-1β-Mϕ promoted a pro-remodeling and inflammatory fibroblast phenotype, unaffected by TGF-β, and more pronounced in sclerodermic efferocytic conditions. Regarding EMT, our results indicate that MVECIL-1β-Mϕ appears to initiate EMT only in SSc conditions, increasing α-SMA and fibronectin expression in CMECs. However, MVEC-Mϕ promoted a pro-fibrotic fibroblast phenotype only in the presence of efferocytic supernatant combined with TGF-β and did not induce EMT initiation. As part of this CIFRE thesis, we explored the anti-inflammatory and pro-resolutive potential of Résolvix, a drug candidate developed by MIP, based on the secretome of Mϕ from healthy subjects who had undergone efferocytosis. Our results show that in the presence of Résolvix, sclerodermic fibroblasts from patients in the early disease stages exhibited a reduced fibrotic profile, favoring a non-inflammatory remodeling phenotype. This result suggests that Résolvix could limit inflammation and fibrosis in patients, and its in vitro testing may help stratify those likely to benefit from the treatment. Our data suggest that efferocytosis plays a variable role depending on MVEC activation, potentially reflecting a sequential role in SSc, where IL-1β is elevated in patients' skin during early stages and TGF-β during later stages. These findings suggest that restoring effective efferocytosis may limit inflammation and fibrosis in scleroderma. Résolvix, by providing anti-inflammatory and pro-resolutive mediators, could restore an anti-inflammatory tissue environment and limit fibrosis, especially in early-stage scleroderma patients.
ED Sciences Physiques et de l'Ingénieur
Linearization of a digital reception chain for a wideband receiver
by Stanislas DUBOIS (Laboratoire de l'Intégration du Matériau au Système)
The defense will take place at 10h00 - Amphithéâtre Jean-Paul Dom IMS Bordeaux - UMR 5218 351 Cours de la Libération, 33405 Talence Cedex, France
in front of the jury composed of
- Dominique DALLET - Professeur des universités - Bordeaux INP - Directeur de these
- Chadi JABBOUR - Maître de conférences - Telecom Paris - Rapporteur
- Christelle AUPETIT-BERTHELEMOT - Professeur des universités - ENSIL-ENSCI-Université de Limoges/Xlim - Examinateur
- Guillaume FERRE - Professeur des universités - Bordeaux INP - CoDirecteur de these
- Salvador MIR - Directeur de recherche - Laboratoire TIMA/CNRS/UGA - Rapporteur
- Jean-Michel HODE - senior expert - THALES DMS - Examinateur
Whether in the context of digital communications, radar or electronic warfare, the transmission and reception chains performing these functions are made up of non-linear components. The latter carry out on the signals of interest the crucial operations of amplification, frequency transposition, and conversion from the analog world of propagation of these signals to the digital world of their processing. In all the contexts mentioned, the instantaneous dynamics is a key performance criterion, determining the spectral leakage at transmission, constraining the flow rate at reception of communication signals, or qualifying the capacity to receive echoes of different powers in radar. Increasing the instantaneous dynamics can be done through the design of the chains, both in the choice of components and in their ordering, and then involves a long and tedious design process, resulting in a sacrifice in terms of cost, size or consumption. The other way of increasing the instantaneous dynamics, which is the subject of this manuscript, is linearization by digital processing, based on behavioral modeling of the transmission or reception chain. This linearization is based on three intrinsically intertwined phases, behavioral modeling, identification of model parameters, and compensation of non-linear faults. After introducing the application context of this work, we begin this manuscript with the development of continuous-time models, based on the derivative of the signal. We thus opt to escape from the formalism of the Volterra series, based on the concept of memory effect, in order to rediscover the physical intuition of the description of the distortion with respect to instantaneous variations of the signal. We then split the identification of the parameters of these models into two phases. Characterization, first of all, brings together methods based on multi-tone signals, combining a relatively simple formalism and easy implementation. This first phase is therefore applied to the study of non-linear behavior, and to the sizing of the model. The second phase, calibration, designates the identification of the parameters of this model from white noise, by correlation, therefore requiring a heavier formalism but allowing a more exhaustive identification, intended for an embedded deployment on FPGA. As such, a first rewriting of the proposed model is introduced, on the basis of orthogonal functions, for the diagonalization of the correlation system. A second rewriting is carried out to apply the theory of multi-rate filtering to the elimination of the aliased distortion in the sampling band. The last object of this thesis work is the application of the methods presented to the realization of a calibration implemented in situ, so as to be able to adapt dynamically to the variation of the non-linear distortion of the chain with regard to the evolution of the airborne radar environment. This implementation assumes the use of the transmission chain in order to inject the calibration stimulus into the reception chain. We thus propose a method allowing the distinction of the non-linear contributions of the transmission and reception chains to the observation of the output of their cascade, in order to identify only the defects of the reception chain, for the linearization of the signal captured by the antenna.
Upper-limb force feasible set: theoretical foundations and musculoskeletal model reconstruction
by Gautier LAISNÉ (Laboratoire de l'Intégration du Matériau au Système)
The defense will take place at 10h00 - Ada Lovelace 200 Av. de la Vieille Tour, 33405 Talence
in front of the jury composed of
- Jean-Marc SALOTTI - Professeur - Bordeaux INP - Directeur de these
- Darwin LAU - Associate Professor - The Chinese University of Hong Kong - Rapporteur
- Charles PONTONNIER - Maître de conférences - ENS Rennes - Rapporteur
- Nasser REZZOUG - Maître de conférences - Université de Poitiers - CoDirecteur de these
- Marc GOUTTEFARDE - Directeur de recherche - LIRMM - CNRS - Examinateur
- Christine CHEVALLEREAU - Directrice de recherche - LS2N-CNRS - Examinateur
In physical Human-Robot Interaction, where robots and humans collaborate on shared tasks through physical contact, such as between the robot's end effector and the human's hand, human safety is a primary concern. This necessitates that the collaborative system inherently consider human characteristics to provide appropriate and safe robotic assistance. To achieve this, it is necessary to evaluate the capabilities of the human upper-limb. In biomechanics, these capabilities are defined through force feasible sets at the hand, which represent all the forces a human operator can exert in a given posture. These three-dimensional sets are influenced by individual factors such as anthropometry and muscle strength and the surface of these sets represents the maximum force capabilities of the human upper-limb in all directions. Therefore, force feasible sets are an invaluable tool for guiding robotic assistance, ensuring it respects biomechanical constraints by remaining within the human's exertable force limits. Force feasible sets are challenging to measure directly but can be partially represented in isometric conditions by measuring maximum exerted forces. Musculoskeletal models, which mathematically represent the human skeleton, joints, and muscles, allow for in silico representation of force feasible sets in various postures through geometric operations (Minkowski sum, projection, intersection) on convex sets. However, these operations are computationally expensive. This thesis first focuses on a novel approach to reduce the computational time of one of the most demanding tasks within this framework. Furthermore, existing in silico models often employ various geometric assumptions about how muscle tensions contribute to joint torques, leading to different characterizations of force feasible sets' shapes, including 3D polytopes and ellipsoids. This thesis proposes a unified framework to represent force feasible sets that explicitly incorporates these geometric assumptions. This framework addresses the limitations of current numerical simulations, which struggle to analyze complex scenarios involving more detailed representation of musculoskeletal models and inherently higher computational costs. In this regard, accurate representation of individual force capabilities requires precise parameterization of musculoskeletal model components. Given the set-theoretic nature of force feasible sets, this thesis introduces an adapted sensitivity analysis tailored to assess the influence of parameters on the geometric properties of force feasible sets. This analysis also highlights the challenges of personalizing musculoskeletal models due to biomechanical inter-variability. Finally, an experimental protocol was established to confront in silico personalization processes with experimentally measured maximal isometric force exertions collected across various postures. Through biomechanical assumptions leading to a computationally less expensive representation of force feasible sets as ellipsoids, muscle parameters personalization is achieved, validating in vivo the theoretically-driven results of this thesis.
ED Sciences et environnements
Covariation of bone and dental tissues in modern humans and evolutionary trends in the human lineage.
by Mathilde AUGOYARD (De la Préhistoire à l'Actuel : Culture, Environnement, Anthropologie)
The defense will take place at 14h00 - Amphithéâtre PABA Amphithéâtre PABA, Allée Geoffroy Saint Hilaire (Campus Bordes - Bâtiment B5) 33615 Pessac CEDEX
in front of the jury composed of
- Priscilla BAYLE - Maîtresse de conférences - Université de Bordeaux - UMR5199 - Directeur de these
- Ottmar KULLMER - Professeur - Senckenberg Research Institute and Natural History Museum Frankfurt - Rapporteur
- Alexandra HOUSSAYE - Directrice de recherche - UMR 7179 MNHN/CNRS - Rapporteur
- Isabelle DE GROOTE - Professeure - Department of Archaeology - Ghent University - Examinateur
- Fernando RAMIREZ ROZZI - Directeur de recherche - UMR 7206 - Biodémographie humaine (BioDemo) - Examinateur
- Clément ZANOLLI - Chargé de recherche - Université de Bordeaux - UMR 5199 - CoDirecteur de these
- Christine VESCHAMBRE COUTURE - Professeure des universités - Université de Bordeaux - UMR5199 - Examinateur
Cortical bone and dentine are two biological tissues sharing a common genetic origin, overall structure, composition, and embryological development, distinct from those of enamel. Although these similarities are well-documented during the early stages of ontogeny, no study has explored the possibility of a joint development of these two tissues at later stages of development. However, studies that independently assess cortical bone and dentine proportions have revealed similarities in robustness between these two tissues in various representatives of the human lineage. For example, Neandertals display higher cortical bone volumes in their infra-cranial skeleton and greater dentine robustness compared to modern humans, while the absolute enamel volumes are similar between the two taxa. Biomechanical constraints could explain a significant part of the differences in bone thickness between Neandertals and modern humans. However, studies of immature Neandertal specimens suggest that their cortical bone and dentine robustness may be present from early developmental stages. This implies that the joint thickening of these two tissues could be primarily influenced by genetic and developmental factors, rather than functional ones. In this doctoral research, we aim to understand whether the structural and developmental affinities between cortical bone and dentine lead to covariation in their volumes in immature individuals, and later in adulthood. To do so, we built a sample of 12 immature individuals and 70 adults. Using microtomographic acquisitions of the arm, forearm bones, and anterior dentition, we conducted a methodological approach combining the quantification of cortical bone and dentine volumes with the analysis of their topographic distribution. We highlight strong positive correlations between cortical bone and dentine volumes, while correlations with enamel are weak or null. The bone-dentine covariation signal is stronger in adults, possibly due to a desynchronization between bone and dental development in immature individuals. The strength of this signal relied on the type of bone and its laterality, which may reflect functional differences between the dominant and non-dominant limbs. Furthermore, the intensity of the signal varied with the chronology of dental formation, with radicular dentine volumes of canines showing the highest correlations with cortical bone, followed by lateral and central incisors. The development of cortical bone and radicular dentine in canines aligns with the pubertal growth spurt period. This suggests that the bone-dentine covariation signal is primarily driven by hormonal factors, further supported by the sexual dimorphism observed in tissue volumes. To investigate the potential for a common evolutionary origin of the bone-dentine covariation between fossil and extant hominins, we conducted a preliminary analysis on chimeric individuals of Paranthropus, Australopithecus, and Neandertals. Most individuals showed a deviation from the modern human bone-dentine relationship, characterized by higher dentine volumes in fossil taxa and cortical bone volumes similar to those of modern humans. A slowdown in growth and development has been described in Homo sapiens compared to fossil hominins, which may explain the unique bone-dentine relationship seen in this taxon. This doctoral thesis provides an original contribution to the study of bone and dental tissue volumes and distribution in various fossil and extant hominin taxa, offering insights into the impact of genetic, environmental, and evolutionary factors acting on their development.
Dynamics of particulate organic matter composition at the continent-ocean interface
by Florian FERCHICHE (Environnements et Paléoenvironnements Océaniques et Continentaux)
The defense will take place at 9h00 - Salle de conférence - Bâtiment Sud Station marine d'Arcachon 2 rue du Professeur Jolyet 33120 Arcachon
in front of the jury composed of
- Nicolas SAVOYE - Physicien CNAP - Université de Bordeaux - Directeur de these
- Yoann COPARD - Professeur des universités - Université de Rouen - Rapporteur
- Tarik MEZIANE - Professeur des universités - Museum National d'Histoire Naturelle - Rapporteur
- Arnaud HUGUET - Chargé de recherche - Sorbonne université - Examinateur
- Nadia SéNéCHAL - Professeure des universités - Université de Bordeaux - Examinateur
Particulate organic matter (POM) plays a key role in the functioning of the ecosystems of the continent-ocean aquatic continuum. POM can be composed of several sources produced in situ (phytoplankton, microphytobenthos, macroalgae) or imported from adjacent ecosystems (terrestrial POM, anthropogenic POM, river, estuarine or marine phytoplankton). Along the fluvial-estuarine continuum, the contribution of each source to the composition of POM varies seasonally and between ecosystems and is strongly influenced by environmental processes (e.g. primary production, deposition-resuspension, remineralisation). This thesis aims to improve (1) the characterisation of the isotopic and elemental signatures of POM sources, (2) the quantification of the composition of POM originating from rivers and being transformed in estuarine systems, (3) the description of the spatiotemporal variability of POM and (4) the understanding of the environmental forcings of this variability. To this end, the composition of POM was estimated using mixing models over twenty-four temperate fluvial-estuarine systems using isotopic and elemental ratios of carbon and nitrogen (δ13C, δ15N and C/N), as well as hydrogen as prospective methodological work (δ2H). The spatiotemporal variability of each of the POM sources was then linked to environmental parameters using multivariate statistics to determine their forcings. Finally, a comparison of systems based on the dynamics of POM composition was proposed. Four types were identified among the twenty-three rivers studied: (1) rivers with POM dominated by labile terrestrial material over the annual cycle, (2) rivers with POM composed of labile terrestrial material and phytoplankton, with marked seasonality due to seasonal blooms or (3) with no marked seasonality, and finally (4) rivers with POM composed of labile terrestrial POM, refractory POM and phytoplankton, linked to contrasting seasonal conditions. The five estuaries studied showed contrasting dynamics in terms of POM composition. In the Elorn and Leyre, riverine POM is replaced at low salinity by phytoplankton produced in the estuary throughout the year. The Aulne functioning is similar but there is a transport of riverine POM further downstream during winter. The Loire estuary POM is composed solely of autotrophic POM, alive in spring or degraded in winter. Finally, the Gironde estuary POM is dominated by refractory terrestrial material throughout the annual cycle. Along the fluvial-estuarine continuum, the fluvial POM has a contrasting composition and spatio-temporal dynamics. The composition of this river-borne POM is then transformed along the estuary into a refractory form by degradation and/or is supplemented by autotrophic living POM produced in situ.
ED Sociétés, Politique, Santé Publique
Cost-effectiveness evaluation of a model of social inclusion and personalised care for people with Alzheimer's disease and related disorders: the "Village Landais Henri Emmanuelli" as an alternative model to nursing homes
by Damien KRIER (Bordeaux Population Health Research Center)
The defense will take place at 14h00 - Site Carreire, Salle de conférence de la plateforme génomique 146, rue Léo Saignat 33076 Bordeaux cedex
in front of the jury composed of
- JEROME WITTWER - Professeur des universités - Université de Bordeaux - Directeur de these
- Hélène AMIEVA - Professeure des universités - Université de Bordeaux, Bordeaux Population Health - CoDirecteur de these
- Agnès GRAMAIN - Professeure des universités - Université de Lorraine - Rapporteur
- Thomas RAPP - Professeur des universités - Université Paris Cité - Rapporteur
- Roméo FONTAINE - Chargé de recherche - INED - Examinateur
- Jean-Luc NOVELLA - Professeur des universités - praticien hospitalier - CHU de Reims - Examinateur
Population ageing is leading to an increase in cases of Alzheimer's disease and related disorders, often associated with dementia. The "Village Landais Henri Emmanuelli" (VLHE) is a unique initiative in France aimed at improving the quality of life for patients, their carers, and healthcare professionals. This thesis evaluates the efficiency of the VLHE compared to a traditional nursing home (NH), focusing on its clinical and economic impacts. The VLHE is the subject of a prospective observational study, the results of which served as the basis for this work. In the absence of a direct counterfactual, control groups consisting of individuals admitted to EHPAD were created using several data sources. The thesis is organised into four chapters: a literature review followed by three comparative analyses on institutional care costs, the use of hospital services, and the clinical progression of individuals with dementia admitted to either VLHE or NH. Clinically, the median survival for individuals with dementia newly admitted to care is approximately 38 months, with no significant difference between those in NH and VLHE. The severity of cognitive impairment, as well as comorbidities such as a history of cancer and hypertension, significantly influence residents' survival. A decline in cognitive and functional abilities is observed following admission to both NH and VLHE, with a potential slowing of this decline in VLHE residents during the first year, although this difference is not statistically significant compared to NH residents. Economically, costs are higher at VLHE, primarily due to a higher staffing ratio, but with reduced use of hospital services and improved end-of-life care. This work provides insights into improving dementia care and highlights the need for further research to validate and expand upon these findings.
Speaking in nursery School : characteristics of verbal productions of talkative or untalkative children and professional language gestures in three activities
by Julie SANCHEZ-GIL (Laboratoire d'épistémologie et didactiques disciplinaires, professionnelle et comparée de Bordeaux)
The defense will take place at 9h00 - Amphithéâtre Averoès 49 rue de l'Ecole Normale 33021 Bordeaux
in front of the jury composed of
- Martine JAUBERT - Professeure des universités - Université de Bordeaux, INSPE de l'académie de Bordeaux - Directeur de these
- Anne CLERC-GEORGY - Professeure des universités - Haute Ecole Pédagogique du canton de Vaud en Suisse - Rapporteur
- Michel GRANDATY - Professeure des universités - Université de Toulouse Jean Jaurès - Examinateur
- Christophe RONVEAUX - Maître de conférences - Université de Genève - Examinateur
- Mylène EYQUEM - Professeure des universités - Université de La Réunion - Rapporteur
Oral language is omnipresent in the classroom, especially in nursery school. However, its teaching remains complex and little implemented, even though it is one of the vectors of school success. This thesis examines the effects of three language activities implemented by a teacher with small groups of kindergarten pupils, selected on the basis of the quantitative and qualitative heterogeneity of their speech. It is part of a socioconstructivist framework that considers the role of interactions between children and their environment in language acquisition to be fundamental. Thus, in our study, carried out in a school context, verbal interactions between teacher and pupils are crucial to the learning of new discourse practices. Our analyses are based on quantitative observables (percentage of speaking time, utterances produced, LME, etc.) and qualitative observables (content of utterances), which enable us to draw up language portraits of the pupils and assess their variations according to the grouping modalities and activities proposed. This study shows that the variation in grouping modalities helps students learn to construct themselves as interlocutors in different contexts. But above all, this research shows that the choice of language activities has a far greater impact than grouping modalities on students' language productions, and more particularly on those of “little” talkers. Our study shows that it is important to vary the language activities aimed at students, so as to inscribe them in different discourse genres and teach them to use a variety of linguistic tools. This research also shows that the nature of the verbal productions of “high” talkers is more heterogeneous than those of “low” talkers. In fact, a language profile common to the “big talkers” in our study emerges during the three activities proposed, since they speak spontaneously, follow up on the teacher's speeches as well as those of their peers, and the content of their speeches is varied. The language profile of “small” talkers is more heterogeneous, and depends more on the activities proposed. Nevertheless, we note some common features, such as the fact that most of them follow on from the teacher's speeches, and often after questioning on her part, or the fact that the content of their speeches is more stable than that of “big” talkers. Finally, the last part of our thesis focuses on the professional language gestures (LPG) mobilized in each of the activities, depending on whether the students are “small” or “big” talkers. This research, carried out with groups of four students, shows that working with a small number of students enables the teacher to feedback and adjust the LPGs to the needs of the students, the latter being different in the “small” and “large” talker groups, which explains why the number of LPGs and the nature of the latter vary according to the group. However, the teacher's representations of “little” and “big” talkers can sometimes have an effect on the LPGs mobilized during the activities.
Development of a method for designing a virtual reality training tool for intervention training on high-risk industrial fires: taking into account the needs of trainers and trainees
by Sarah MORELOT (Bordeaux Population Health Research Center)
The defense will take place at 14h00 - Bat E, Amphithéatre 15, rue Naudet CS 10207 33175 Gradignan Cedex France
in front of the jury composed of
- Philippe ALLAIN - Professeur des universités - Université d'angers - Rapporteur
- Julien NELSON - Maître de conférences - Université Paris Cité - Examinateur
- Alain GARRIGOU - Professeur des universités - Université de Bordeaux - Directeur de these
- Valérie SAINT DIZIER - Professeure des universités - Université de Lorraine - Examinateur
- Bernard N'KAOUA - Professeur des universités - Université de Bordeaux - CoDirecteur de these
- Catherine DELGOUELT - Professeure des universités - CNAM - Rapporteur
This thesis deals with the development of a method for designing a virtual reality tool for fire training. Fire is a major catastrophe, and the human and material costs can be extremely high. In recent years, new technologies have been used to develop ever more effective fire-fighting and prevention tools. In this context, the emergence of virtual reality offers new prospects for improving fire training. Technological advances are leading to the digitization of professional training courses. These new technologies are freeing us from the constraints of the real world and opening a whole new world of possibilities. However, it is legitimate to ask how these technologies have been thought out and developed from the point of view of pedagogical objectives and learning processes. Indeed, these technologies sometimes mobilize logics that respond more to marketing issues than to the development of trainees' ability to act. And yet, working in a new world of digital technologies radically transforms our relationship with work situations. Our research work is positioned in this context of digitization of work, questions about its impact on users' work activities (trainers and trainees), and methods for designing environments using virtual reality for fire training. The aim of our thesis is to develop a method for redesigning a virtual environment for fire training. To achieve this, we adopted a multi-disciplinary approach, drawing on both activity-based ergonomics and cognitive science methodologies for designing user-friendly digital tools. The ergonomic approach enabled us to gain a better understanding of the work situation, its determinants, the activity deployed and the impact of the introduction of a digital tool on work activity and on workers. In addition, the cognitive science perspective has enabled us to gain a better understanding of the methods used to design this type of digital tool, as well as their characteristics and capacity to enhance learning. Our work has mobilized these two disciplines with different and complementary methodologies and approaches. Our concern for synthesis was to meet the challenges associated with these specific work situations (fire safety), but also to meet the challenges associated with the characteristics of digital tools and their ability to promote the development of procedural skills (sensory-motor learning) and conceptual skills of trainees, while taking into account the needs of trainers to lead their training situations so that their work is not hindered by this tool. Despite the diversity of approaches to designing virtual environments, developing useful tools that are usable and acceptable to both end-users remain a major challenge. A specific co-design method has been developed, enabling the results of work situation analyses and tools to be used as design resources. It places particular emphasis on including users in the process, thus promoting a participative approach. The challenge in designing virtual training environments (VTE) lies in the design of three fundamental elements: the training scenario, the behavioral interface and the man-machine interface. This co-design methodology aims to provide a systematic approach to designing virtual environments so that they are more useful, usable and acceptable.