ED Mathématiques et Informatique
A micrograin formalism for the rendering of porous materials
by Simon LUCAS (LaBRI - Laboratoire Bordelais de Recherche en Informatique)
The defense will take place at 14h30 - Ada Lovelace 200 Av. de la Vieille Tour, 33405 Talence
in front of the jury composed of
- Pascal BARLA - Chargé de recherche - INRIA Bordeaux - Directeur de these
- Holly RUSHMEIER - Professeure - Yale University - Rapporteur
- Nicolas HOLZSCHUCH - Directeur de recherche - INRIA Rhône-Alpes - Rapporteur
- Romain PACANOWSKI - Chargé de recherche - INRIA Bordeaux - CoDirecteur de these
- Lionel SIMONOT - Maître de conférences - Université de Poitiers - Examinateur
- Daniel MENEVEAUX - Professeur - Université de Poitiers - Examinateur
This thesis focuses on the impact of microscopic structures on material appearance, with a particular emphasis on porous materials. We first evaluated existing appearance models by conducting light transport simulations on sphere aggregates representing porous volumes. We found that none of the existing models accurately matched the simulations, with most errors arising from surface effects. This opened the path to the development of a specialized Bidirectional Scattering Distribution Function (BSDF) model for rendering porous layers, such as those found on surfaces covered with dust, rust, or dirt. Our model extends the Trowbridge-Reitz (GGX) distribution to handle pores between elliptical opaque micrograins and introduces a view- and light-dependent filling factor to blend porous and base layers. By adding height-normal and light-view correlations in the masking and shadowing terms, our model produces realistic effects seen in real world materials that were previously hardly obtainable like retro-reflection and height-color correlations. To improve the rendering efficiency of micrograin materials, we introduce an efficient importance sampling routine for visible Normal Distribution Functions (vNDF). Through numerical simulations, we validate the accuracy of our model. Finally, our work provides a comprehensive formalism for rendering porous layers and opens many perspectives of futur work.
Strategies in problem-solving : a model to cluster problem-solving behaviours
by Axel PALAUDE (LaBRI - Laboratoire Bordelais de Recherche en Informatique)
The defense will take place at 9h00 - Centre Broca Nouvelle Aquitaine, 3ème étage Institut des Maladies Neurodégénératives Université de Bordeaux 146, rue Léo Saignat 33076 Bordeaux Cedex
in front of the jury composed of
- Thierry VIEVILLE - Directeur de recherche - Centre INRIA de l'Université de Bordeaux - Directeur de these
- Yann SECQ - Maître de conférences - Université de Lille - Examinateur
- Morgane CHEVALIER - Professeure des universités - Haute Ecole Pédagogique de Vaud - Examinateur
- Gayo DIALLO - Professeur des universités - ISPED / Université de Bordeaux - Examinateur
- Sophie MORLAIX - Professeure des universités - Université de Bourgogne - Rapporteur
- Iza MARFISI - Maîtresse de conférences - Le Mans Université - Rapporteur
Learning regulation is the set of skills that facilitate learning. This includes motivational and emotional skills, as well as meta-cognition skills, such as monitoring goals and strategies. Learning situations are present in every-day life, and mostly take the form of open problems, problems for which there is an unknown solution or method to achieve them. Open problem solving requires learning unknown elements, which requires regulation skills. Understanding the strategies used by learners to solve open-ended problems allows us to better understand the regulation processes and therefore the learning process. Regulatory processes can be influenced and trained, and this understanding of the processes could lead, to better-suited teaching methods. This thesis presents a model representing the learning process of a learner confronted with an open problem, as well as a method allowing, based on external observations of actions carried out by learners, to group problem-solving sequences depending on the strategies used. The analysis methods use clustering algorithms, which using dynamic time warping as a measure of similarity between problem-solving sequences. This dynamic time warping measure is applied to symbolic data, which can be compared through the use of proper metrics. In the context of small datasets, a meta-clustering method is presented for robustness purposes. Two case studies use the method defined here to show the potential uses of such a method but also to discuss its limitations. The first, CreaCube, is the study of a creative problem-solving task, in which we try to understand the processes of creativity. Second, Outer Wilds tries to extend the analysis to long problems.
Modelling of aeroelasticity in large transformations by partitioned coupling: application to large wind turbines.
by Caroline LE GUERN (IMB - Institut de Mathématiques de Bordeaux)
The defense will take place at 15h30 - AMPHI_SE-052 1-4 Av. du Bois Préau, 92852 Rueil-Malmaison
in front of the jury composed of
- Michel BERGMANN - Professeur - Université de Bordeaux - Directeur de these
- Axelle VIRé - Full professor - TU Delft - Examinateur
- Matteo CAPALDO - Docteur - TotalEnergies - Examinateur
- Angelo IOLLO - Professeur - Université de Bordeaux - Examinateur
- Joris DEGROOTE - Full professor - Ghent University - Rapporteur
- Niels SøRENSEN - Full professor - Technical University of Denmark - Rapporteur
The increasing size and complexity of modern wind turbines, particularly those in offshore settings, present significant challenges for aeroelastic modelling. These turbines are characterised by long and slender blades that are highly flexible, making them susceptible to deformation under varying aerodynamic loads. This flexibility introduces unsteady inflow conditions due to the blades' motions. The aerodynamic behaviour of wind turbines is often modelled using the Blade Element Momentum (BEM) theory, which is computationally efficient but considered a low-fidelity approach, requiring empirical corrections to account for unsteady conditions. In this thesis, a medium-fidelity approach, the Free Vortex Wake (FVW) method, is chosen for aeroelastic simulations. Unlike BEM, the FVW method directly captures complex phenomena such as non-uniform inflow, unsteady blade-element behaviour, and blade-wake interactions, providing a more accurate representation of the aerodynamic forces. However, due to its computational intensity, the FVW method is not yet suitable as a practical design tool compared to the more efficient BEM approach. To optimise the use of FVW methods in aeroelastic simulations, this work explores different partitioned coupling techniques. Aeroelastic modelling of wind turbines is here achieved by coupling a structural Finite Element (FE) solver with a FVW solver using partitioned time integration coupling approaches like the Conventional Serial Staggered (CSS) scheme and a subcycling technique. The CSS scheme allows each solver to operate independently and exchange data at every time step, but it can become restrictive when different time discretisations are needed for the fluid and structural solvers. In contrast, the subcycling technique allows each solver to use different time steps, with data exchange occurring only at the larger time step intervals, offering a more flexible approach. This work compares these coupling techniques across different model problems to assess their accuracy, stability, and computational cost under various conditions. First, a simplified linear problem is used, where a structural oscillator equation is coupled with wake dynamics modelled by a Van der Pol equation. This allows for an initial evaluation of the numerical properties of each coupling method. Next, a more complex pitch-heave problem is introduced, using a simplified finite element model for the structure and a Python-based, lifting-line filament FVW code for the aerodynamics. This python code was specifically developed for this thesis, providing a user-friendly solver for testing aerodynamic or fluid-structure interactions problems. Finally, these partitioned approaches were implemented within an advanced aero-servo-elastic modelling tool to analyse their effects on a large-scale wind turbine problem. The analysis reveals how different coupling methods impact the computational efficiency of aeroelastic simulations, demonstrating that subcycling can significantly reduce computation times while preserving accuracy when using FVW methods for aerodynamic modelling.
Optimal stochastic control and application on passive trajectography
by Romain NAMYST (IMB - Institut de Mathématiques de Bordeaux)
The defense will take place at h00 - Salle 1 351, cours de la Libération 33405 Talence Institut de Mathématiques de Bordeaux
in front of the jury composed of
- François DUFOUR - Professeur des universités - Bordeaux INP - Directeur de these
- Antoine GRALL - Professeur des universités - Université de Technologie de Troyes - Rapporteur
- Benoîte DE SAPORTA - Professeur des universités - Université de Montpellier - Rapporteur
- Dann LANEUVILLE - Ingénieur de recherche - Naval Group - Examinateur
- Audrey GIREMUS - Professeure des universités - Université de Bordeaux - Examinateur
- Alexandre GENADOT - Maître de conférences - Université de Bordeaux - CoDirecteur de these
The objective of this thesis is to study optimal control problems in a partially observed discrete-time framework. In particular, we are interested in the stochastic optimal control problem for estimating the position of an underwater target from noisy measurements coming from a sensor owned by an underwater observer. We propose to use the Markov Decision Process (MDP) formalism, which is a family of controlled processes particularly well suited to modelling sequential stochastic optimisation problems. From a theoretical point of view, PDMs have been studied very intensively in the literature. There are numerous techniques for establishing theoretical results showing the existence of optimal strategies or characterising the properties of the value function. These techniques are centred around dynamic programming and linear programming. However, it should be emphasised that such approaches do not provide either explicit solutions (except for very specific cases) or approximations of these optimal solutions, particularly in the context of partial and noisy observations. This thesis will focus on developing new theoretical/numerical approaches to approximation techniques for solving partially observed PDMs, analysing the problem of localisation and tracking in the plane and in a context of angular observations, analysing the convergence of the proposed approximation schemes and implementing an algorithm for solving the problem described at the beginning of this paragraph.
Standardized numerical simulations of cardiac electrical stimulation devices
by Valentin PANNETIER (IMB - Institut de Mathématiques de Bordeaux)
The defense will take place at 10h00 - Salle de conférences Salle de conférence Institut de Mathématiques de Bordeaux UMR 5251 Université de Bordeaux 351, cours de la Libération - F 33 405 TALENCE
in front of the jury composed of
- Yves COUDIÈRE - Professeur des universités - Université de Bordeaux - Directeur de these
- Chloé AUDEBERT - Maîtresse de conférences - Sorbonne Université - Examinateur
- Christèle ETCHEGARAY - Chargée de recherche - Centre Inria de l'université de Bordeaux - Examinateur
- Stéphanie SALMON - Professeure des universités - Université de Reims - Examinateur
- Olivier BERNUS - Professeur des universités - Université de Bordeaux - Examinateur
- Romano SETZU - Docteur - MicroPort CRM - Examinateur
- Marcela SZOPOS - Professeure des universités - Université Paris Cité - Rapporteur
- Youcef MAMMERI - Professeur des universités - Université Jean Monnet - Rapporteur
Cardiovascular diseases are the world's leading cause of death, responsible for around 32% of all deaths in 2019, according to the World Health Organization (WHO). Faced with these pathologies, medical research is making constant progress to develop ever more effective treatments and devices. Among these innovations, implantable pacemakers play a crucial role in the treatment of cardiac rhythm disorders, intervening directly on the heart in the event of malfunction. Despite their importance, the development of these technologies remains slow and costly. It often takes almost a decade from early prototyping to market launch, delaying their impact on human lives. This thesis is part of the European collaborative project SimCardioTest (EU H2020), which aims to accelerate the adoption of numerical tools for the certification of drugs and medical devices, such as implantable pacemakers. One of the main goals of the project is to integrate numerical simulations in the form of in silico clinical trials on a standardized web platform in order to speed up the certification process. During this thesis, several mathematical models were developed and analyzed, ranging from generic three-dimensional models to simplified models with no spatial dimension. All these models include an electrical circuit inspired by a commercial pacemaker, contact models representing the ionic layers on electrode surfaces as equivalent electrical circuits, and cardiac tissue models with or without spatial propagation of cardiac action potentials. The credibility of these models is assessed through comparisons with animal experiments conducted during the thesis, with the aim of demonstrating their ability to reproduce realistic cardiac stimulations. These comparisons are based mainly on the voltages measured by pacemakers, and on the study of threshold curves, also known as Lapicque curves. These curves, widely used clinically to adjust pacemakers, establish the relationship between stimulation duration and amplitude required to induce an effective cardiac contraction. In particular, they enable pacemaker settings to be optimized through individual customization, thereby minimizing energy consumption, maximizing device life, and therefore improving patient's life quality. The adoption of simplified dimensionless models is an valuable strategic step in this thesis. Unlike spatial models, which are very costly to solve numerically, these models are simpler to solve and have enabled several parametric studies to be carried out, in particular to perform calibration using experimental data. Additional sensitivity studies, both local and global, were also carried out to analyze the influence and relevance of the parameters in the developed models.
ED Sciences Chimiques
Fluorescent and Functional Organic Nanoparticles for Biosensing and Bioimaging
by Ophélie DAL PRA (Institut des Sciences Moléculaires)
The defense will take place at 14h00 - Salle de conférence, 3ème étage EST Batiment A12 Institut des Sciences Moléculaires Bâtiment A12 — 351 Cours de la Libération 33405 TALENCE cedex
in front of the jury composed of
- Gilles CLAVIER - Directeur de recherche - ENS Paris-Saclay - Rapporteur
- Andreas REISCH - Maître de conférences - Université de Strasbourg - Rapporteur
- Suzanne FERY-FORGUES - Directrice de recherche - Université Toulouse III - Paul Sabatier - Examinateur
- Morgane ROSENDALE - Chargée de recherche - Université de Bordeaux - Examinateur
- Jean-Baptiste VERLHAC - Professeur des universités - Université de Bordeaux - Examinateur
Thanks to their high brightness and photostability, fluorescent nanoparticles are a promising alternative to organic fluorophores, especially in the fields of biomedical imaging and biosensors. For these applications, the most established nanoparticles are Quantum Dots, as well as silica or polymer nanoparticles that are doped with fluorophores or lanthanides. An alternative to these nanomaterials is the use of fluorescent organic nanoparticles (dFONs) obtained by nanoprecipitation of dedicated hydrophobic dyes in water. Thanks to the high concentration of fluorophores in the core of dFONs, they can exhibit exceptional brightness and photostability. Their preparation method is simple and can be used on a wide variety of chromophores, enabling modulation of their brightness and emission wavelength. However, the challenge for these dFONs lies in the development of efficient and robust functionalization methods, which would facilitate their use as biomarkers or biosensors. This work focuses on the development of new functional dye structures and the preparation of surface-reactive organic nanoparticles for bioimaging. The first section presents the synthesis and characterization of a new dye bearing maleimide functions. The dFONs obtained from this dye are thiol-reactive, and could be used as blue-emitting intracellular glutathione sensors, allowing both 1- and 2-photon excitation. The covalent surface functionalization of these dFONs with various biomolecules is presented as part of a proof-of-concept study. In addition, studies on non-functionalized model chromophores were carried out to better understand the impact of dye structural modification on the photophysical properties of the resulting dFONs and their behaviour in the cellular environment. The limitation of this first dye is its blue emission wavelength, which is poorly suited to biological tissues. With this in mind, the next section presents red-emitting dyes whose synthesis can be modulated, thus allowing the introduction of reactive functions. In particular, it was shown that these new red dFONs could internalize into eukaryotic cells and label lipid droplets (under 1- and 2-photon excitation). However, this work on dFONs has also highlighted their limitations in terms of surface functionalization, notably in regard to maintaining dFONs integrity. In the future, it would be interesting to develop a covalent link between chromophores within dFONs to improve their cohesion and enable them to be used as biomarkers in complex biological environments.
Research on the precursors of molecular markers of "dried fruit" aromas in red grapes from Vitis Vinifera
by Dalila LAMLIJI (Institut des Sciences Moléculaires)
The defense will take place at 14h00 - Amphithéâtre G Bâtiment Licence - A29 Amphithéâtre G Université de Bordeaux - Campus Talence 33400 Talence
in front of the jury composed of
- Svitlana SHINKARUK-POIX - Ingénieure de recherche - Bordeaux Sciences Agro - Directeur de these
- Florine CAVELIER - Directrice de recherche - Institut des Biomolécules Max Mousseron UMR 5247 IBMM - Rapporteur
- Chrystel LOPIN-BON - Professeur des universités - Université d'Orléans - ICOA UMR 7311 - Rapporteur
- Jean-Christophe BARBE - Professeur des universités - BORDEAUX SCIENCES AGRO - Examinateur
The aromatic quality of wine, closely related to the presence of volatile compounds, is influenced by multiple factors, including grape variety, ripeness, winemaking methods, and climatic conditions. These compounds are often present in grapes in a bound form (as precursors) and are therefore non-odorants. The presence of aromas associated with overripe grapes, as 'dried fruit' notes (prune, fig), is particularly sensitive to theclimate change, especially in wine regions such as Bordeaux. This thesis aims to elucidate the origin of the compounds responsible for the 'dried fruit' aromas in red wines, specifically caramel-scented furanone (4-hydroxy-2,5-dimethyl-3(2H)-furanone) and prune kernel-like 3-methyl-2,4-nonanedione (MND). Based on literature and preliminary experiments, we hypothesized the existence of glycosylated precursors and pro-precursors and developed a strategy to identify them in grapes and wines. This research was extended to two other furanones of oenological interest, sotolon (3-hydroxy-4,5-dimethylfuran-2(5H)-one) and abhexon (2-hydroxy-5-methyl-3-hexanone). Our approach is structured around two complementary strategies. The first includes the synthesis of glycosylated standards of the target compounds, considering their stereochemistry. Several O-glucosidation strategies were optimized using three different glucose donors. Various deprotection methods were tested, followed by a multi-step purification process involving silica chromatography and high-performance liquid chromatography (HPLC). The synthesized compounds were then characterized by nuclear magnetic resonance (NMR) to identify the formed isomers and by high-resolution mass spectrometry (HRMS). The optimization of analysis conditions in LC-MS/MS and HRMS of wines, musts, and red grape berries of different varieties (Merlot, Cabernet Sauvignon, and Grenache) allowed us to validate, for the first time, the existence of the glycosylated precursor of furanone in its β-form in oenological samples. The second strategy focuses on uisng glucosidase enzymes immobilized on γ-Fe₂O₃/polymer core-shell magnetic nanoparticles to release volatile aromas from their bound forms. The biofunctionalized nanoparticles were characterized by transmission electron microscopy (TEM) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. The enzymatic activity of the grafted glucosidases was tested in must and wine model solutions . Preliminary results show that immobilized β-glucosidases retain good enzymatic activity, while the efficiency of α-glucosidases decreases under oenological conditions, requiring further optimization. These results pave the way for in-depth research into the presence of glycosylated compounds in musts and wines, with the aim of better understanding their formation and, ultimately, optimizing grape maturity for harvesting and red wine aging potential.
Hydrogen-deuterium exchange coupled to native mass spectrometry of nucleic acids
by Matthieu RANZ (Acides nucléiques : Régulations Naturelles et Artificielles)
The defense will take place at 14h00 - Amphithéâtre Bâtiment Bordeaux Biologie Santé (RDC) Bâtiment Bordeaux Biologie Santé, 2 rue du Dr Hoffman Martinot, 33000 Bordeaux
in front of the jury composed of
- ERIC LARGY - Maître de conférences - Université de Bordeaux - Directeur de these
- Emmanuelle LEIZE-WAGNER - Directrice de recherche - Unversité de Strasbourg - Rapporteur
- Brahim HEDDI - Chargé de recherche - Laboratoire de biologie et pharmacologie appliquée (LBPA) - Rapporteur
- Jean-Louis MERGNY - Directeur de recherche - LABORATOIRE D'OPTIQUE ET BIOSCIENCES - Examinateur
- Cherine BECHARA - Professeure - Université de Montpellier - Examinateur
- Karen GAUDIN - Professeure - Univeristé de Bordeaux - Examinateur
- Julien MARCOUX - Directeur de recherche - IPBS-Toulouse - Examinateur
G-rich DNA oligonucleotides can form non-canonical secondary structures called G-quadruplexes (G4). These structures consist of stacks of G-tetrads, formed by the association of 4 guanines linked together by a double network of 8 hydrogen bonds and stabilized by interactions with a metal cation (usually K+ or Na+). G4s are involved in the regulation of several critical biological processes, particularly in telomeres and oncogene promoters, and are considered as promising therapeutic targets due to their structure, which is very distinct from the canonical double helix. Current high-resolution structural characterization methods are only limited to the characterization of unique conformers. However, G4s often adopt several conformations in dynamic equilibrium. To overcome this limitation, we introduce hydrogen-deuterium exchange coupled with mass spectrometry (HDX/MS). This technique, already commonly used for protein characterization, has been recently adapted for the study of DNA oligonucleotides. HDX is based on the ability of the amino and imino protons of G4s to exchange with the deuterons of the solvent, which can be quantified by MS. Their exchange rate depends on the involvement of the protons in hydrogen bonds, their protection from the solvent and therefore on the structure of the oligonucleotide. Here, we couple HDX with native mass spectrometry, which allows the study of non-covalent complexes resolved in mass. The aim of this thesis is to develop, understand, and exploit the native HDX/MS technique for the study of G4s. This approach is divided into five parts. The first presents the methods and tools for interpreting native HDX/MS results applied to G4s. It notably demonstrated that exchange kinetics reflect a precise number of G-tetrads and that exchange rates are proportional to the stability of oligonucleotides in solution. The study of isotopic distributions across the exchange also provides information on the unfolding rate, which allows to detect weakly folded intermediates, invisible with other techniques. In the second part, we established the influence of fundamental parameters (pH, temperature, cation, ionic strength) on the measured exchange kinetics. Then, by coupling HDX with ion mobility mass spectrometry in the third part, we characterized structural dynamics of noncovalent complexes of same mass, in particular those formed by the human telomeric sequence. In the fourth part, we applied HDX/MS developments to the study of complexes formed by G4s and small molecules/peptides. We established trends between binding modes and the HDX/MS kinetics measured simultaneously on different mass-separated species, alongside affinity measurements (KD). In a fifth, more exploratory part, we examined the structural impact of nucleotides located on 5' and 3' ends on a telomeric sequence of fixed length. HDX was here included in a multi-technique analytical approach. The association of HDX and native MS with other techniques is therefore promising and could help to characterize more complex systems (DNA/proteins complexes, mRNAs).
Linear block copolysaccharides of chitosan and dextran for nucleic acid delivery
by Elise COURTECUISSE (Laboratoire de Chimie des Polymères Organiques)
The defense will take place at 9h30 - Amphi 1 Bâtiment A 16 Avenue Pey Berland 33600 Pessac
in front of the jury composed of
- Christophe SCHATZ - Maître de conférences - Bordeaux INP - Directeur de these
- Alexandra MONTEMBAULT - Professeure - Université Claude Bernard Lyon 1 - Rapporteur
- Luc PICTON - Professeur - Université de Rouen - Rapporteur
- Lourdes Mónica BRAVO-ANAYA - Chargée de recherche - CNRS - Examinateur
- Chantal PICHON - Professeure - Université d'Orléans - Examinateur
- Gilles JOUCLA - Maître de conférences - Bordeaux INP - Examinateur
- Bertrand GARBAY - Professeur - Bordeaux INP - Examinateur
- Bjørn E. CHRISTENSEN - Professeur - Norwegian University of Science and Technology - Examinateur
Chitosan, the only positively charged polysaccharide in acidic medium, can form polyelectrolyte complexes with negatively charged molecules. This property makes it a promising candidate for the design of non-viral nucleic acid delivery systems. However, at physiological pH, its low degree of protonation renders it insoluble, promoting the aggregation and precipitation of complexes. Chemical modifications of chitosan affect its integrity and, in some cases, compromise its complexation properties. This study explores two strategies to stabilize the complexes formed between chitosan and DNA. The first approach is based on the use of linear block copolysaccharides chitosan-b-dextran. Due to its hydrophilic nature and ability to limit aggregation, dextran improves the solubility and dispersion of the complexes in aqueous media. The integrity of chitosan is preserved by using a diamine as linker to couple polysaccharide blocks through their reducing ends. Among the commercial diamines tested, O,O'-1,3-propanediylbishydroxylamine (PDHA) was preferred due to the stability of the oxime bonds formed, eliminating the need for a reduction step. The second approach combines the acetylation of chitosan with the addition of zinc ions to the complexes formed with DNA. Degrees of acetylation greater than 40%, in combination with zinc forming coordination bonds with chitosan and DNA, resulted in particularly stable complexes under physiological conditions. Both strategies were evaluated through transfection tests of the eGFP plasmid on HEK 293 cells. Although the expression of the fluorescent protein was lower than that obtained with a commercial transfection agent like PEI, the addition of a dextran block significantly improved the transfection rates compared to chitosan alone.
ED Droit
Fundamental rights of employers
by Pauline FLEURY (COMPTRASEC - Centre de Droit Comparé de Travail et de la Sécurité Sociale)
The defense will take place at 14h00 - Salle des thèses 16 avenue Léon Duguit, 33600 PESSAC
in front of the jury composed of
- Gilles AUZERO - Professeur des universités - Université de Bordeaux - Directeur de these
- Elsa PESKINE - Professeure des universités - Université Paris Nanterre - Rapporteur
- Alexandre FABRE - Professeur des universités - Université Paris 1 Panthéon Sorbonne - Rapporteur
- Véronique CHAMPEIL-DESPLATS - Professeure des universités - Université Paris Nanterre - Examinateur
- Christophe RADE - Professeur des universités - Université de Bordeaux - Examinateur
The impact of fundamental rights upon labor law is not a new topic. Numerous works have brilliantly analyzed the contribution of fundamental rights to the protection of employees. However, until now, the employer's fundamental rights have received little interest. Usually, employers are not understood as the subject of such rights. Vested with authority over others and often embodied by a legal entity, employers do not fit with the figure of the oppressed individual seeking protection of their basic rights. However, the present thesis aims to demonstrate that the employer, regardless of its legal form, holds fundamental rights and freedoms, which can have a significant impact on the employment relationship. Invoked vertically against public authorities, these rights contribute to challenge labor law, in the name of economic priorities. On the other hand, invoked horizontally – either against employees or against other actors such as trade unions or social security funds – the employer's fundamental rights struggle to be asserted. Ultimately, the study highlights the growing submission of labor law to the fundamental rights' logic. A constant process of balancing the rights and freedoms of each contract's parties is now required, reinforcing the role of judges. It is also the very logic of fundamental rights and freedoms that is affected by these developments. No longer serving solely to protect individuals against abuses of power, these rights are also being mobilized by powerful economic operators, in order to strengthen their own authority.
A critical essay on the law of retention : Avocacy for a reform of OHADA's law
by Ismael GUINDO (INSTITUT DE RECHERCHE EN DROIT DES AFFAIRES ET DU PATRIMOINE)
The defense will take place at 14h00 - Manon Cormier 16 Avenue Léon Duguit, 33600 Pessac
in front of the jury composed of
- Denis POHE-TOKPA - Maître de conférences - Université de Bordeaux - Directeur de these
- Moussa THIOYE - Professeur des universités - Université Toulouse Capitole - Rapporteur
- Yodé Jean-Didier KAKALY - Professeur des universités - Université Alassane Ouattara - Rapporteur
- Bernard SAINTOURENS - Professeur émérite - Université de Bordeaux - Examinateur
In a vision of attractiveness and competitiveness in the life of affairs, the ohada's law wants to be a tool of juridical security so that to attract foreign investors and permit a dynamism of national investments. However, the aroused hopes by this juridical system are far to be consolidated. The results of the OHADA remain unclear after more than thirty (30) years of existence. From this remark and by the prism of the law of sureties, we are free to ask questions on the capacity of the OHADA's law to bring sufficient guaranties in the relationship between the creditor and the debtor. The particular case of the retention law which effectiveness is compromised for its inadequate appproach, is an indicator on the necessity of a new approach of the law of sureties in its enirety. Shouldn't we rethink the skeleton and the structuration of the law of sureties in african law ? This current study suggests an approach which priorises the realities of the juridical environnment of the OHADA so that to find a deep reshape which will give back to the OHADA law its real position that it must hold face to the economic challenges of its space.
The evolution of defence cooperation in Europe. Research on a method revealing the specifity of the European Union.
by Anne-Hélène BERTANA (CENTRE DE RECHERCHES ET DE DOCUMENTATION EUROPÉENNES ET INTERNATIONALES)
The defense will take place at 14h00 - 1K Pôle juridique et judiciaire de l'université de Bordeaux 35 place Pey-Berland 33000 Bordeaux
in front of the jury composed of
- Anne-Marie TOURNEPICHE - Professeur des universités - Université de Bordeaux - Directeur de these
- Elsa BERNARD - Professeur des universités - Université de Lillle - Rapporteur
- Didier BLANC - Professeur des universités - Université Toulouse Capitole - Rapporteur
- Nabli BELIGH - Professeur des universités - Université Paris Est Créteil - Examinateur
- Olivier DUBOS - Professeur des universités - Université de Bordeaux - Examinateur
The defence cooperation within the EU, which can possibly evolve into a common defence, is singular. Firstly, because defence is a sovereign domain, so the States tend to limit their legal commitments. Consequently, it's an intergovernmental cooperation, even if most of the EU's policies are based on the integration method. This cooperation is influenced by the failure of the EDC, the mixed results of the WEU and its coexistence with NATO. However, its inclusion in the EU legal order differentiates this defence cooperation, because of its link with the processes of integration. It is therefore anchored by an unprecedented legal base, with an evolutionary nature which allows a gradual intensification of cooperation towards a shift to the integration method. Furthermore, EU instruments support this process. As the defence cooperation is included in an international integration organisation, it allows a global approach to security and defence issues, linked with other policies useful for addressing security challenges. The various supranational bodies and institutions of the Union contribute to promoting the development of defence cooperation and the establishment of a common defence. Ultimately, some elements of the EU integration method are progressively incorporated into the intergovernmental functioning of defence cooperation. Nevertheless, the outcome of this process remains dependent on the political choices related to the modalities of cooperation, which need to be transformed to achieve integration, and to the relations with NATO. Therefore, the evolution of the methods used to develop and to implement the defence policy reveals the EU distinctive dynamism and appears as an institutional and legal response to the challenges raised by defence cooperation in Europe.
ED Sciences de la Vie et de la Santé
Characterization of a patatin-like phospholipase involved in lipid droplet biology in Trypanosoma brucei
by Perrine HERVE (Microbiologie fondamentale et Pathogénicité)
The defense will take place at 10h00 - Amphithéâtre BBS Bâtiment BBS 2 Rue du Dr Hoffmann Martinot 33000 Bordeaux
in front of the jury composed of
- Loïc RIVIERE - Professeur des universités - Université de Bordeaux - Directeur de these
- Catherine JACKSON - Directrice de recherche - Université Paris Cité - Rapporteur
- Rachel CERDAN - Professeure des universités - Université de Montpellier - Rapporteur
- Maude LEVEQUE - Maîtresse de conférences - praticienne hospitalière - Université de Montpellier - Examinateur
- Sébastien MONGRAND - Directeur de recherche - Université de Bordeaux - Examinateur
African trypanosomes are flagellated protozoan parasites responsible for deadly diseases in humans (Human African trypanosomiasis or sleeping sickness) and animals (animal African trypanosomiasis or Nagana). Trypanosoma brucei is the study model for these pathogens. This parasite alternates between a mammal host and a bloodsucking insect that allows vectorial transmission, the tsetse fly, found in Sub-Saharan Africa. During this lifecycle, the pathogen must cross several tissues (skin, bloodstream and lymph and adipose tissue in the mammal; midgut and salivary glands in the insect), and shows great capacities of adaptation in these different environments. To complete this cycle and adapt to its hosts, T. brucei is able to quickly modify its morphology and metabolism. In this context, the mobilization and utilization of lipids is particularly essential to the parasite's survival. These molecules are involved in various cellular processes, including the maintenance and renewal of cellular membranes (made of phospholipids), energy metabolism, cellular signaling pathways and gene expression regulation. This mobilization is made possible by a highly dynamic compartment called lipid droplets. This atypical organelle, surrounded by a monolayer of phospholipids, forms a metabolic platform and represents a growing interest in human health due to its potential roles in metabolic and neurodegenerative diseases, as well as cancers. In protozoan parasites, the very recent interest in lipid droplets shows roles in the survival and virulence in the mammal host. The objective of this thesis was to identify and characterize new proteins associated with the lipid droplets of T. brucei to understand the organelle's function in the parasite. We discovered a new phospholipase of the patatin-like family, which we called TbPat. We showed through different imaging techniques that TbPat localizes to the surface of the lipid droplets of the parasites. The expression of this protein is tightly regulated and can be induced during the formation of new lipid droplets, demonstrating the implication of this protein in the dynamics of the compartment. Overexpression and deletion of the protein significantly impacts the diameter and number of lipid droplets in the parasites, associated with a complete remodeling of their lipid profile. Finally, directed mutagenesis coupled with lipidomic analysis showed that TbPat is an active phospholipase. This project allowed the characterization of the first phospholipase involved in lipid droplet biology in trypanosomes, and paves the way for new studies to elucidate the functions of this organelle in protozoan parasites and in other, more complex eukaryotic cellular types.
Ultrastructural and molecular analysis of cortico-striatal dopamine hub synapses
by Paul LAPIOS (Institut Interdisciplinaire de Neurosciences)
The defense will take place at 9h30 - Salle de conférence CARF Centre d'Appui à la Recherche et à la Formation (CARF) Site Carreire de l'Université de Bordeaux 146, rue Léo Saignat 33076 Bordeaux cedex.
in front of the jury composed of
- David PERRAIS - Directeur de recherche - University of Bordeaux UMR5297 - Directeur de these
- Jean-Antoine GIRAULT - Directeur de recherche émérite - Sorbonne University UMR-S 1270 - Examinateur
- Aude PANATIER - Directrice de recherche - University of Bordeaux U1215 - Examinateur
- Ira MILOSEVIC - Associate Professor - University of Oxford - Rapporteur
- Benoît ZUBER - Professeur - University of Bern - Rapporteur
Dopamine is a neurotransmitter that modulates neuronal activity and governs essential functions such as reward prediction, motivation, and motor control. In the striatum, dopamine typically acts over a large volume through slow-acting metabotropic receptors. However, recent studies have demonstrated that dopamine can also operate in localized hotspots measuring a few cubic micrometers. Additionally, dopamine may trigger excitatory synapse potentiation when released in synchrony with glutamate. Despite these advances, molecular and ultrastructural studies have been limited by technical challenges. During my doctoral training, I developed cutting-edge techniques to explore the molecular and ultrastructural features of dopaminergic terminals and their relationship to synapses in the mouse striatum. In a first piece of work, we aimed at analyzing the composition of dopaminergic (DA) terminals. To that end, we labeled dopaminergic neurons with a green fluorescent reporter under the control of the Dopamine Transporter promoter (DAT-cre line). Following subcellular fractionation of the striatum, we isolated green fluorescent synaptosomes (resealed terminals bound to synaptic partners) with fluorescence-activated synaptosome sorting (FASS). Immunolabeling of these isolated DA synaptosomes confirmed the presence of genuine dopaminergic markers apposed to dopamine receptors. Surprisingly, 30% of dopamine synaptosomes were bound to cortico-striatal excitatory synapses expressing the type 1 vesicular glutamate transporter (GLU). We termed these connections cortico-striatal dopamine hub synapses (DHS). On these samples, I used 6 markers of the GLU pre- and post-synapse to scrutinize the effect of the association in DHS. I could identify that the association in DHS corelates with a molecular remodeling of the cortico-striatal synapses (1). Dopamine hub synapses may thus serve as a structural substrate for localized dopamine activity in the striatum and could further potentiate glutamatergic signaling. Next, I established a cryo-correlative light and electron microscopy (cryo-CLEM) protocol on labeled synaptosomes to determine the ultrastructure of dopamine terminals and DHS in three dimensions. Compared to cortico-striatal pre-synapses, DA synaptosomes were three times smaller and contained ten times fewer synaptic vesicles (SVs). The size and shape of SVs in DA terminals were more heterogeneous; they were generally larger and sometimes elongated. While GLU synapses exhibited active zones (AZ) and postsynaptic densities, DA terminals lacked distinct vesicle clusters or clear synaptic organization. Only 35% of dopamine terminals contained at least one tethered SV required for exocytosis. In these terminals, SVs were more abundant and closer to the plasma membrane, suggestive of a higher release activity. However, primed SVs (tethered within 5 nm of the plasma membrane) were absent. Interestingly, GLU terminals in DHS had more primed SVs compared to regular GLU synapses, implying that the presence of DA terminals reorganizes SVs in glutamatergic terminals. These results suggest that the interaction of DA terminals with synapses modifies the release properties of GLU pre-synapses by a local dopamine-dependent plasticity (2). Given that dopamine dysregulation is implicated in addiction and Parkinson's disease (for which effective treatments are limited), the discovery of this multipartite structure responsible for specific dopamine activity on glutamatergic inputs represent a new conceptual framework for future studies in the field. Modulating the physical interaction between DA and GLU synapses in vivo could provide a new method to influence dopamine signaling in the striatum. (1) Paget-Blanc V et al., (2022) A synaptomic analysis reveals dopamine hub synapses in the mouse striatum. Nat Commun 13:3102 (2) Paul Lapios, Robin Anger, Vincent Paget-Blanc, Vladan Lučić, Rémi Fronzes, Etienne Herzog#, and David Perrais# (2024) In preparation
ED Sciences Physiques et de l'Ingénieur
Teleoperation for the remote expression of technical gestures : application to formulation in chemistry.
by Erwann LANDAIS (Institut national de recherche en informatique et en automatique - Bordeaux - Sud-Ouest)
The defense will take place at 9h30 - Salle Ada Lovelace INRIA Bordeaux Sud Ouest, 200 avenue de la Vieille Tour, 33400 Talence
in front of the jury composed of
- Vincent PADOIS - Directrice de recherche - INRIA Bordeaux Sud Ouest - Directeur de these
- Caroline MORICOT - Maîtresse de conférences - Université Paris 1 Panthéon-Sorbonne - Rapporteur
- Marie BABEL - Professeure des universités - INSA Rennes - Rapporteur
- Pauline MAURICE - Chargée de recherche - CNRS, LORIA - Examinateur
- Martin HACHET - Directeur de recherche - Inria Bordeaux Sud Ouest - Examinateur
- Gérard POISSON - Professeur des universités - Université d'Orléans - Examinateur
- Nasser REZZOUG - Maître de conférences - Université de Poitiers - CoDirecteur de these
Teleoperation enables a task to be carried out remotely by a human expert. This remote control is often a guarantee of greater safety and comfort, or simply of feasibility in hazardous environments. However, it can also mean a loss of efficiency, or added complexity. To avoid these pitfalls, it is necessary to consider 1) what constitutes an operator's expertise for a given task, 2) the constraints encountered in carrying it out, and 3) the form of a teleoperation system adapted to it. An example of a task that could benefit from teleoperation is the task of finding solvents for chemical compounds, which is one of Syensqo's areas of expertise. This involves characterizing the solubility of a solute in a set of solvents, in order to determine the optimum solvent for that solute. This task, based on visual, cognitive and manual expertise, is performed by a small number of expert technicians. Performing this task relies on an empirical, tedious and sometimes dangerous process, motivating the distancing of technicians from the experimental environment through robotic assistance. Using this task as a case study, this thesis aims to answer the following questions: on the one hand, how can an operator's expertise be preserved when performing a task using a teleoperated system? And on the other hand, how can the suitability of a teleoperation solution for performing an expert task be assessed? To answer these questions, a broad-spectrum literature review was carried out and two experimental studies were conducted. In these, the relevance of remote task performance modalities was analyzed in relation to the manual mode. To enable these studies to be carried out under secure conditions, the proposed modalities were tested on a reading task. The texts read are inscribed on capsules, placed in vials carried by a robot controlled by the user. The user observes the vials remotely via a camera. In the first study, user control is limited to real-time modification of the robot's temporal profile (speed, direction of travel) along a set of pre-determined Cartesian paths. Different types of modulation (on visual feedback, or on the robot's trajectory) are evaluated. The results of this experiment show that these modalities enable the task to be carried out, but lead to a degradation in performance that disqualifies their applicability. This degradation is due to the lack of richness in the proposed interactions. In the second study, a robot was designed to achieve a range of motion similar to that observed in technicians, and intuitive interfaces were used to define the desired movement of the vial in real time. The study shows that controlling the robot via these interfaces does not achieve an efficiency similar to that of the manual mode. However, the performance achieved is encouraging, and the study identifies several avenues of improvement for the efficient and reliable deporting of the technical gesture in chemistry. Finally, beyond the application framework, this work establishes a comprehensive methodology for evaluating the performance of teleoperation modalities.
ED Sociétés, Politique, Santé Publique
RESILIENCE OF HEALTHCARE SYSTEMS TO MAJOR EPIDEMICS IN AFRICA: THE IMPACT OF COVID-19 ON THE CONTROL OF PRIORITY DISEASES IN TOGO
by Yao KONU (Bordeaux Population Health Research Center)
The defense will take place at 9h00 - Salle de visioconférence n°4 146 Rue Léo Saignat, 33000 Bordeaux, France
in front of the jury composed of
- DIDIER KOUMAVI EKOUEVI - Professeur - Université de Bordeaux - Directeur de these
- Karine LACOMBE - Professeure des universités - praticienne hospitalière - Sorbonne Université - Rapporteur
- Pierre-Marie PREUX - Professeur des universités - praticien hospitalier - Université de Limoges - Rapporteur
- Dominique SALMON - Professeure des universités - praticienne hospitalière - Université Paris Descartes - Examinateur
- Amadou ALIOUM - Professeur des universités - Université de Bordeaux - Examinateur
Context: The resilience of a healthcare system is its ability to prepare for, manage and learn from shocks. Particularly during health crises such as the COVID-19 pandemic, health systems must simultaneously fulfill two functions: responding to the crisis and maintaining the provision of essential health services. In sub-Saharan Africa, the management of HIV, malaria and tuberculosis is essential. Indeed, it is on this continent that the burden of these three major infectious diseases is heaviest. In Togo, the first case of COVID-19 was reported on March 6, 2020. In response to the pandemic, the government has promoted various general and public health measures. These measures are likely to have adversely affected access to and utilization of care for the three major infectious diseases. That said, few data are available on the effect of the COVID-19 pandemic on health system indicators and performance in sub-Saharan Africa, and more specifically in Togo. The aim of this thesis is to contribute to the resilience of healthcare systems in the face of major epidemics in Africa. Methods: In this thesis, we i) described the COVID-19 epidemic in Togo and its management by the health authorities through a narrative review ; ii) measured the intensity of the epidemic shock through a series of seroprevalence studies in the general population and in specific populations and finally ii) described the impact of the pandemic on the use of services related to the fight against HIV, malaria and tuberculosis in Togo via a time series analysis to measure changes in levels between the prepandemic (January 2019 to March 2020) and perpandemic (April 2020 to December 2021) periods. The agreement of Togo's Bioethics Committee for Health Research will be obtained. At the end of this project, we will have taken stock and produced factual data on the impact of the COVID-19 pandemic on the fight against HIV, malaria and tuberculosis in Togo. Results: We report a high prevalence of SARS-CoV-2 in the general population in 2021 (65.5%; confidence interval (CI95%): 64.3 -66.6) and among street adolescents in 2022 (63.5%; CI95%: 57.8-69.0). HIV, malaria and tuberculosis services were generally maintained in Togo despite the COVID-19 pandemic. Overall, there was a decrease in six of the nine included indicators, ranging from 19.3% (Incidence Rate Ratio (IRR): 0.807; CI95%: 0.682-0.955) for hospitalization of malaria patients to 36.9% (IRR: 0.631; CI95%: 0.457-0.871) for GeneXpert diagnosis of tuberculosis, immediately following the declaration of the COVID-19 pandemic. The trend remained constant between the COVID-19 pre-pandemic and pandemic periods for all malaria indicators. A significant monthly downward trend was observed for initiation of antiretroviral therapy (IRR: 0.909; CI95%: 0.892-0.926) and positive TB microscopy (IRR: 0.919; CI95%: 0.880-0.960). Conclusion: This thesis work has provided epidemiological data on the COVID-19 epidemic in Togo and on the effect of the pandemic on the use of services for three priority diseases. These results should serve as a basis for anticipating the consequences of future health crises linked to emerging infectious diseases in Togo and beyond in Africa.
School inclusion of students with special educational needs and teacher training: a study of teachers in Haiti and France.
by Amente DESINOR (Laboratoire Cultures, Education, Sociétés)
The defense will take place at 14h30 - visioconférence
in front of the jury composed of
- Régis MALET - Professeure des universités - Université de Bordeaux - Directeur de these
- Sylvie CONDETTE - Professeure des universités - Université de lile - Rapporteur
- Magdalena KOHOUT-DIAZ - Professeure des universités - Université de Bordeaux - Examinateur
- Lijuan WANG - Chargée de recherche - Université de Oulu - Examinateur
- Damus OBRILLANT - Professeur associé - Université Sherbrooke –Québec - Examinateur
- Francklin BENJAMIN - Professeur associé - Université Quisqueya et université d'État d'Haïti - Examinateur
- Komlan Kwassi AGBOVI - Professeur des universités - Université de Lomé - Rapporteur
The education of pupils with special needs calls into question the way in which teachers are trained in the exercise of their profession. This requires teachers to be prepared to deal with the difference and diversity of pupils, as required by the new inclusive paradigm. One of the ways in which teachers can help is by providing appropriate teaching in the classroom to meet the particular needs of their pupils. So the question is, how can these teachers be supported to meet these new challenges? The aim of this thesis is to study the schooling of pupils with special educational needs and teacher training in Haiti, taking into account contextual variables in other countries, particularly France. A first study addresses some of the factors involved in school inclusion, paying particular attention to teacher training and pedagogical practices, as well as to the difficulties encountered by teachers. This research is not a comparative study, but rather a case study of the two countries mentioned. The analysis of the first study is based on declarative data collected using a mixed-method approach, including questionnaires and semi-structured interviews with primary and secondary school teachers in France and Haiti. The second study involved a training program for fifteen Haitian teachers. The results show that most teachers use a variety of pedagogical practices, mainly derived from traditional methods. At the same time, the effect of training on the practices implemented by the teachers was analyzed. The results indicate that training influences teachers' practices, as shown by the number of teachers who adopted certain practices after training to better welcome pupils.
SCIENCE AND ITS FOOTPRINT. A SOCIOLOGY OF SCIENTIFIC MOBILIZATIONS ON CO2e
by Antoine HARDY (Centre Emile Durkheim)
The defense will take place at 13h30 - Salle Copernic Sciences Po Bordeaux 11 All. Ausone, 33600 Pessac
in front of the jury composed of
- Daniel COMPAGNON - Professeur des universités - Université de Bordeaux - Directeur de these
- Johanna SIMEANT-GERMANOS - Professeur des universités - ENS / CMH - Rapporteur
- Morgan JOUVENET - Directeur de recherche - Laboratoire Printemps - UVSQ - Rapporteur
- Isabelle BRUNO - Maître de conférences - Université de Lille / Ceraps - Examinateur
- Olivier MARTIN - Professeur des universités - Cerlis - Examinateur
- Soraya BOUDIA - Professeur des universités - Cermes3 - Examinateur
This dissertation focuses on the social “traces” of climate geophysics within the public research sector in France at the turn of the 2020s. It follows an attempt to “decarbonise” research and its implications for the construction and circulation of knowledge and the authority of science. Drawing on a processual and interactionist sociology, this dissertation explores the social world of carbon quantification in public laboratories: actors who organise themselves to produce new data through a quantification process in order to analyse greenhouse gas emissions at laboratory scale, expressed in carbon dioxide equivalents, and to try to identify and implement measures to reduce them. Using qualitative data rooted in the sociology of science and situated at the intersection of the social studies of quantification and environmental sociology, this research aims to understand why and how these actors seek to impose constraints on themselves at a given moment. It identifies different ways of working, knowing, and engaging in research professions, the values that underpin these activities, and how scientific work, or what it should be, is normatively charged. The dissertation describes and analyses a reconfiguration of the moral background of science within this social world, leading its actors to question practices and representations that were previously unquestioned, or not questioned on this basis, and thereby to engage with the epistemic, material, and ethical boundaries of science.