ED Droit
Gabonese professional risks law. Study in the light of French law.
by Romaric Leonce NGAMBA MBONGO (COMPTRASEC - Centre de Droit Comparé de Travail et de la Sécurité Sociale)
The defense will take place at h00 - Salle des thèses Université de Bordeaux site Pessac-Montesquieu 16 Avenue Léon Duguit, 33608 Pessac Cedex
in front of the jury composed of
- Maryse BADEL - Professeure des universités - Université de Bordeaux - Directeur de these
- Jean-Claude JAMES - Professeur agrégé - Université Omar BONGO - Rapporteur
- Romain MARIE - Professeur des universités - Université Lyon 2 Lumière - Rapporteur
- Isabelle DESBARATS - Professeure des universités - Université Toulouse 1 Capitole - Examinateur
- Loic LEROUGE - Directeur de recherche - Université de Bordeaux - Examinateur
The study of Gabonese law on occupational risks involves determining the criteria for the application of legislation on occupational risks under the social security scheme. Since the adoption of the social security code in 1975, this legislation has been linked to the employment contract. If in the past, this affiliation had a progressive character in that it guaranteed all employees the benefit of protection against the three legal forms of occupational risks (work accidents, commuting accidents, and occupational diseases), it now tends to reveal shortcomings regarding the personal and material scopes of this legislation, as well as concerning the benefits. Indeed, the legislation on occupational risks struggles to cover workers classified as employees and self-employed workers, meaning those who do not hold an employment contract. The legislation on professional risks indeed struggles to cover workers who are similar to employees and independent workers, that is to say, people who do not hold an employment contract. It also excludes certain workers such as public agents, who nonetheless benefit from the administrative provisions outlined by the civil service regulations, and domestic workers who, due to employers' refusal to pay social contributions, are deprived of any protection. The inadequacy of the employer's authority, an indicator of legal subordination and of the presence of an employment contract, in relation to the diseases listed in the tables of occupational diseases, similarly reflects this insufficiency and calls for a reference to what could be called the the « risk of employment ». Finally, the principle of automatic and flat-rate compensation resulting from the legal link between the employment contract and the legislation on occupational hazards often leads to depriving the employee or their beneficiaries of full compensation for damages resulting from the occurrence of the risk. The existing legislative and regulatory framework indeed imposes on them a remaining charge and exposes them to incomplete compensation. In light of these shortcomings, a overhaul of the legal framework related to occupational risks seems necessary and urgent.
ED Sciences de la Vie et de la Santé
Impact of exogenous G-CSF on the pro-tumoral functions of immunosuppressives myeloid cells induced by breast cancers
by Alexandra MOISAND (Immunologie Conceptuelle, Expérimentale et Translationnelle)
The defense will take place at 14h00 - Salle de conférence Centre d'Appui à la Recherche et de Formation 146 rue Léo Saignat 33000 Bordeaux
in front of the jury composed of
- Nicolas LARMONIER - Professeur des universités - Université de Bordeaux - Directeur de these
- Philippe SAAS - Professeur des universités - praticien hospitalier - Université de Grenoble - Rapporteur
- Elise DELUCHE - Professeure des universités - praticienne hospitalière - CHU Limoges - Rapporteur
- Sandrine POGLIO - Maîtresse de conférences - Université de Bordeaux - Examinateur
- Léonie ALRAN - Praticienne hospitalière - Institut Bergonié - Examinateur
To this day, breast cancers represent the first feminine cancer in France as the incidence and mortality rates testify. The high heterogeneity associated with these cancers is a known factor impacting therapeutic strategies for patients. In this context, the development of immunotherapies for breast cancers remains limited, notably due to a marked resistance. Among the multiple mechanisms explaining this phenomenon, the cellular interactions occurring within the tumor microenvironment, especially ones involving immunosuppressive myeloid cells, have been proposed to play a central role. The dynamics of their recruitment and activation are currently well known; however, doubts still subside on whether these same mechanisms can be influenced by therapeutical interventions. This is particularly the case for prophylactic, or exogenous, G-CSF, which is used alongside myeloablative chemotherapies. This doctoral research thus aimed at evaluating the potential modulating effect of exogenous G-CSF on the expansion and the pro-tumoral functions of immunosuppressive myeloid cells in breast cancers.
Study of the bioaccessibility and bioavailability of polyphenols from a grape and blueberry extract and carotenoids from a saffron extract
by Lisa TEXIER (Oenologie)
The defense will take place at 9h00 - Amphithéâtre Institut des Sciences de la Vigne et du Vin, 210 Chemin de Leysotte, 33140 Villenave d'Ornon, France
in front of the jury composed of
- Stephanie KRISA - Professeure des universités - Université de Bordeaux - Directeur de these
- Sylvain GUYOT - Directeur de recherche - INRAE Rennes - Rapporteur
- Claudine MANACH - Ingénieure de recherche - INRAE - Université Clermont-Auvergne - Rapporteur
- Emmanuelle REBOUL - Directrice de recherche - INRAE - Aix-Marseille Université - Examinateur
- Benoit CUDENNEC - Professeur des universités - Université de Lille - Examinateur
Demographic aging is one of the greatest economic and societal challenges of the 21st century. While increased life expectancy represents a major achievement, it is accompanied by a rising prevalence of chronic diseases. In this context, nutrition, as a modifiable behavioral factor, paves the way for preventive approaches to promote healthy aging. Certain dietary patterns, such as the Mediterranean diet, a source of polyphenols and carotenoids, have been associated with protective effects on health. Inspired by these observations, the dietary supplement industry has developed ingredients concentrated in these phytonutrients to support healthy aging. Nevertheless, despite documented benefits, the bioavailability of some of these compounds remains poorly understood, limiting the identification of the forms responsible for the observed effects. It is within this context that the work described in this manuscript was conducted, focusing on two ingredients: Memophenol™, an extract of grape and wild blueberry, and Safr'Inside™, a saffron extract. The study focused on their main polyphenols and carotenoids, namely catechin and epicatechin for Memophenol™, and crocins for Safr'Inside™. Their bioaccessibility was first assessed using the in vitro gastrointestinal model INFOGEST 2.0. The results suggest that co-ingestion with a meal promotes the preservation of the compounds during digestion, whereas administration in the form of capsules or gummies has only a limited effect on their bioaccessibility. Furthermore, phase II metabolism was investigated using human and rat liver protein extracts. Glucuronides formed in vitro from catechin and epicatechin were identified, and their formation was enzymatically characterized. New metabolites derived from crocetin (glucuronides and isomers) were also found using human microsomes. Finally, the metabolized forms produced in vitro were detected in vivo in blood samples following ingestion of the ingredients during clinical studies, reinforcing the relevance of our model. This work highlights, for the first time, novel metabolized forms of polyphenols and carotenoids from commercial ingredients, opening new perspectives for understanding their benefits in the context of healthy aging.
Deciphering the role of very long chain fatty acids (VLCFA)-lipids in auxin cell signaling and in the control of de novo organogenesis in Arabidopsis thaliana.
by Matheus MONTRAZI (Laboratoire de Biogenese Membranaire)
The defense will take place at 14h00 - Colette & Josy Bové 71 Av. Edouard Bourlaux Amphithéâtre Colette & Josy Bové 33140 Villenave-d'Ornon
in front of the jury composed of
- Yohann BOUTTE - Directeur de recherche - Université de Bordeaux - Directeur de these
- Julien GRONNIER - Professeur - Technical University of Munich - Rapporteur
- Juliette JOUHET - Directeur de recherche - Laboratoire de Physiologie Cellulaire & Végétale (LPCV) - Rapporteur
- Soazig GUYOMARC'H - Professeure - University of Montpellier - Examinateur
- Derek MCCUSKER - Directeur de recherche - Institut de Biochimie et Génétique Cellulaires est rattaché au Département Sciences Biologiques et Médicales de l'Université de Bordeaux - Examinateur
La phytohormone auxine déclenche plusieurs voies de signalisation importantes pour le développement des plantes. L'auxine est impliquée dans la division, l'élongation et la différenciation cellulaires. L'un de ces processus est l'assemblage des nanodomaines de ROP6, une GTPase impliquée dans diverses activités cellulaires, notamment le gravitropisme, l'indentation des cellules épidermiques des feuilles et la formation de racines latérales. En effet, l'auxine active ROP6, qui interagit avec la phosphatidylsérine (PS) dans la membrane plasmique (PM) via une interaction électrostatique entre le domaine C-terminal chargé négativement de ROP6 dans sa forme active et la tête polaire chargée positivement de la PS. Comme les nanodomaines sont des phases ordonnées non mobiles, on suppose que les acides gras à très longue chaîne (VLCFA) de la PS et les sphingolipides sont impliqués dans ce processus. Pour étudier cette hypothèse, des plantes ont été traitées avec du métazachlore, un médicament qui raccourcit les chaînes d'acides gras en inhibant les enzymes ketoacyl synthase (KCS), qui sont responsables de l'allongement des chaînes d'acides gras. Les plantes traitées au métazachlore ont été observées par microscopie confocale et par microscopie à épifluorescence à angle variable. Des analyses de mobilité latérale par récupération de fluorescence après photoblanchiment (FRAP) ont montré que la fraction mobile de la PS augmentait sous l'influence du métazachlore, ce qui indique que les chaînes sont impliquées dans la mobilité de la PS. Les images de microscopie à épifluorescence à angle variable (VAEM) ont révélé que le nombre de nanodomaines marqués par le ROP6 diminuait après un traitement au métazachlore. Cela suggère que la longueur de la chaîne joue un rôle dans la formation des nanodomaines ROP6 dans la membrane plasmique. Notamment, le métazachlore raccourcit globalement les chaînes d'acides gras chez les plantes, c'est-à-dire que la PS et les sphingolipides sont affectés simultanément. Afin d'étudier l'effet des sphingolipides, le pool de sphingolipides contenant de très longues chaînes peut être restauré en ajoutant un acide gras à 24 carbones (C24) au milieu de croissance. Des analyses LC-MS/MS ont été réalisées pour quantifier l'effet de l'acide gras sur le pool de sphingolipides. Les analyses FRAP ont montré que le C24 restaure la fraction mobile des lipides de la PS, indiquant que les chaînes de sphingolipides sont impliquées dans la mobilité de la PS. La VAEM a également révélé que le C24 restaure le nombre de clusters ROP6. En collaboration avec des biologistes computationnels, nous avons utilisé des simulations de dynamique moléculaire et mis en évidence l'existence d'un couplage interfeuillets impliquant les VLCFAs de PS et les sphingolipides. Ces résultats ont également montré que le feuillet externe de la MP, qui est beaucoup plus rigide que le feuillet interne. Etant donné que la PS est située dans le feuillet interne de la membrane plasmique et les sphingolipides dans le feuillet externe, les acides gras à très longue chaîne de la PS et des sphingolipides permettraient un couplage entre les deux feuillets de la membrane plasmique, créant ou stabilisant les nanodomaines ROP6. Pour tester l'importance des nanodomaines ROP6 pour le développement des plantes, nous avons analysé les cibles en aval de la signalisation de l'auxine, telles que l'organisation des microtubules, le gravitropisme des racines et l'organogenèse de novo des racines latérales. Le développement des racines latérales est déclenché par l'auxine, et l'un des facteurs de transcription, PUCHI, est impliqué dans l'expression des gènes KCS qui codent pour des enzymes produisant des VLCFA. Le mutant PS synthase pss1 et plusieurs mutants sphingolipides présentent un retard dans le développement des racines latérales suggérant que ces lipides jouent un rôle dans l'organisation spatiale des primordia des racines latérales lors de l'organogenèse de novo.
ED Sciences et environnements
Development of new statistical learning algorithms to couple climate projections and past observations in order to reduce the uncertainties of future climate change.
by Valentin PORTMANN (Environnements et Paléoenvironnements Océaniques et Continentaux)
The defense will take place at h00 - Salle Univers B18N, Allée Geoffroy Saint-Hilaire - 33615 PESSAC
in front of the jury composed of
- Anne GÉGOUT-PETIT - Professeur des universités - Université de Lorraine - Rapporteur
- Florian SÉVELLEC - Directeur de recherche - Université de Brest - Rapporteur
- Aurélien RIBES - Cadre scientifique - Institut de Mathématiques de Toulouse - Examinateur
- Juliette MIGNOT - Directeur de recherche - Sorbonne Université - Examinateur
Climate changes due to human greenhouse gas emissions. Climate models can be used to project how it will evolve based on future human emission scenarios (SSPs). However, the results of the various climate models developed around the world differ quantitatively, generating considerable uncertainty, subsequently called model uncertainty. This model uncertainty is particularly strong for the Atlantic Meridional Overturning Circulation (AMOC), a system of ocean currents that affects climatic conditions in many regions of the globe. Indeed, although all CMIP6 climate models predict a slowdown in the AMOC, the magnitude varies greatly: on average, they project an AMOC slowdown of 33 ± 36% by 2100 (90% confidence, SSP2-4.5 scenario). To reduce model uncertainty, observational constraint (OC) methods have recently been developed. These methods constrain climate models projections using actual observations of one (univariate) or several (multivariate) variables. However, these approaches are difficult to use because in the literature (i) the statistical foundations on which they are based are not always identical and often lack clarity, (ii) the approaches are very diverse and often univariate, and (iii) the choice of observable variables is subjective. This thesis consists of three articles, each addressing one of these three issues. (i) The first article proposes a rigorous statistical model for multivariate linear CO, called ClimLoco1.0. It takes into account the uncertainty in the actual observation and the uncertainty arising from the limited number of climate models, both of which are often neglected or poorly considered in the literature. For the sake of pedagogy, the article gradually details the construction of ClimLoco1.0 and provides graphical interpretations of the mathematical results obtained. (ii) The second article compares the performance of four CO approaches using cross-validation. The future AMOC is constrained either by the past AMOC (univariate) or by the past AMOC, surface temperature and salinity of various subjectively selected ocean regions (multivariate). The most effective approach is Ridge regression in the multivariate case, which is particularly suited to our study. It provides an estimate of the AMOC slowdown by 2100 of 51 ± 8% (SSP2-4.5). This slowdown, which is greater than that estimated by the multi-model average (33%), is mainly due to the consideration of the bias in climate models concerning surface salinity in the South Atlantic. This is consistent with the literature linking this bias to the salt-advection positive feedback, a key mechanism for AMOC stability. (iii) The third article uses a specific clustering method to create groups of regions associated with numerous climate variables. These groups are interpreted to identify the mechanisms that explain the model uncertainty of the future AMOC. They are also summarised by synthetic variables that are used in the ClimLoco1.0 method to constrain this model uncertainty. This method suggests that model uncertainty is explained in particular by the salt-advection positive feedback and deep water upwelling, in line with the literature. Constrained by the observation of these synthetic variables, the estimate of AMOC slowdown by 2100 is 45 ± 10% (SSP2-4.5). The last two articles estimate a similar AMOC slowdown, which is greater and less uncertain than that estimated by the simple multi-model average. It therefore seems appropriate that this result be taken into account in order to improve climate projections and associated adaptation strategies.
ED Sociétés, Politique, Santé Publique
From emotion to sharing: The influence of emotional cues on the attentional and motivational processes driving the diffusion of misinformation
by Aurélien BREST (Laboratoire de Psychologie)
The defense will take place at 9h30 - Denucé Campus Victoire, 3ter place de la Victoire 33000 Bordeaux
in front of the jury composed of
- Théodore ALEXOPOULOS - Professeur des universités - Université de Bordeaux - Directeur de these
- Marie-Pierre FAYANT - Professeur des universités - Université Paris Cité - CoDirecteur de these
- Leila SELIMBEGOVIC - Professeure des universités - Université de Poitiers - Rapporteur
- Pascal WAGNER-EGGER - Professeur titulaire - Université de Fribourg - Rapporteur
- Mathieu CASSOTTI - Professeure des universités - Université Paris Cité - Examinateur
- Annique SMEDING - Professeure des universités - Université Savoie Mont Blanc - Examinateur
The circulation of socio-political misinformation on social media has become a central concern in contemporary democracies. A substantial body of research has sought to identify the factors that lead individuals to share such information with their peers. Two main theoretical models dominate the literature. The first emphasizes social motivations tied to political identity, which guide diffusion behaviors by strengthening individuals' willingness to defend their ingroup. The second highlights the role of inattention and information-processing modes, positing that the diffusion of misinformation primarily results from a neglect of its veracity. Although often presented as competing explanations, these two models can be considered complementary in accounting for the spread of misinformation. The proposed integration rests on analyzing the influence of emotional cues—both the emotional connotation of misinformation and individuals' affective reactions—on the diffusion process. This influence would operate at at two stages of diffusion: during the selection stage, when individuals direct their attention toward particular pieces of information, and during the evaluation stage, when they determine whether it is pertinent to share the selected information. This manuscript advances the hypothesis that emotional cues are a key driver of misinformation spread. The emotional connotation of misinformation should increase its probability of being selected, especially when it is concordant with preexisting beliefs. In addition, affective reactions—most notably anger elicited by contexts perceived as threatening or unjust—should raise the probability of sharing by prompting individuals to evaluate misinformation in terms of their motivation to defend their cause. From an empirical standpoint, this work underscores the importance of further investigating the role of attentional mechanisms in the diffusion of misinformation and highlights the central role of anger in this process. From a theoretical standpoint, the integrative framework advanced here provides research directions that require further elaboration, particularly by clarifying how social motivations and inattention interact during the selection and evaluation stages of misinformation.
Choosing private religious education: motivations and strategies of families in Gabon
by Nancy DELICAT MOUNDOUBE (Laboratoire Cultures, Education, Sociétés)
The defense will take place at 9h30 - Salle du conseil 3 Ter place de la Victoire 33000 Bordeaux
in front of the jury composed of
- Jean-François BRUNEAUD - Professeur - Université de Bordeaux - Directeur de these
- Sabatier FABIEN - Professeur - STAPS - CoDirecteur de these
- Zarrouk SONDESS - Professeure - Université de Haute-Alsace - Rapporteur
- Françoise LORCERIE - Directrice de recherche émérite - Iremam - Rapporteur
- Géraldine FARGES - Professeure - Université Bourgogne Europe - Examinateur
Choosing a school for one's child may initially seem like desirable practice. However, it can also be perceived as a contentious issue (Ben Ayed, 2011). It is contentious because some researchers view these choice practices as an expression of "school consumerism" (Ballion, 1982) or a "close relationship with school segregation" (Van Zanten, 2009, p. 25). It is in this sense that we became interested in families' choices of private religious education in Gabon. Considering that the Gabonese scientific landscape addressing school choice processes is, to date, relatively unexplored, this thesis aims to clarify the issue and provide insight into the construction of quality judgments of a good religious school. The problem posed by this research is the issue of the hierarchy of religious educational offerings in Gabon, particularly in Libreville. This problem leads us to formulate the following general question: Why and how to choose a school for your child, in anticipation of the confessional school offerings, in Libreville This thesis, situated within a comprehensive interpretative framework, draws inspiration from Van Zanten's (2009) interactionist sociology on school choices, from family sociology (de Singly, 2010 and Déchaux, 2010), while paying particular attention to the impact of capital in the sociology of social reproduction according to the perspective of Bourdieu (1979) and Bourdieu and Passeron (2011). Based on forty-five semi-structured interviews conducted with parents residing in three municipalities of the capital (Libreville, Akanda, Owendo). The inductive analysis of the data reveals a significant variability in family choice processes, developed according to conditions, differentiated resources, subjective perceptions, and objective constraints. Indeed, these are strongly indexed based on the availability of educational services in the families' areas of residence and conditioned by the parents' socioeconomic status, the child's status within the family, and their relationship with the various heads of family.
Heading a government department. Prosopography of the senior management of the French State (1990-2025)
by Nicolas BINA (Centre Emile Durkheim)
The defense will take place at 14h00 - Salle de comité de direction 20 place des vins de France, 75012 Paris
in front of the jury composed of
- Cécile VIGOUR - Directrice de recherche - Université de Bordeaux - Directeur de these
- Delphine DULONG - Professeure des universités - Université Paris 1 – Panthéon Sorbonne - Rapporteur
- François-Xavier DUDOUET - Directeur de recherche - Université PSL Paris-Dauphine - Rapporteur
- Camille BEDOCK - Chargée de recherche - Université de Bordeaux Sciences Po Bordeaux - Examinateur
- Natacha GALLY - Maîtresse de conférences - Université Paris 2 - Panthéon-Assas - Examinateur
- Sarah KOLOPP - Maîtresse de conférences - Université Paris 1 – Panthéon Sorbonne - Examinateur
- Jean-Michel EYMERI-DOUZANS - Professeur des universités - UT Capitole Sciences Po Toulouse - Examinateur
At the crossroads of ministers, cabinets and the administrations they lead, directors of central administrations occupy little-known positions within the French civil service. At the crossroads of research on institutions and the state, elites and gender, this study sheds light on the role, socialization and practices of these individuals appointed by the Council of Ministers. Taking the act of appointment to these positions as the starting point for a longitudinal study of careers, this thesis analyses the trajectories, socio-professional characteristics and perceptions of all individuals appointed to these positions between January 1st 1990 and January 1st 2025 (n = 1,446) across all ministries. Based on a mixed-methods survey, the research draws on the analysis of a new database and some twenty semi-structured interviews with (former) directors. Built around career progression (geographical origins, educational and career paths, professional practices and margins), this research provides a complete prosopography of a social group at the very top of the state and highlights the common socialization factors among its members. Access to these positions depends on a combination of numerous and diverse resources accumulated over the course of individual careers. "Sons of the Republic" or from the state nobility, such individuals have more diverse origins than studies on similar populations suggest. While the study of academic backgrounds reveals three main categories (generalists, specialists and technicians), the longitudinal analysis of careers shows career paths that bear the mark of ministerial departments. The study of ministerial cabinets, as places where certain functions are performed and as environments for daily interactions, does not constitute a sine qua non condition in order to be appointed to these functions. This work also shows the daily practices, which do not differ significantly between departments, and the thwarted feminization of these administrative environments, which continue to reproduce inequalities despite the greater presence of female directors. The study of the edges of these functions offers a new perspective on little-known aspects of these professional environments perceived by the power of their attributes and outlines a form of impoverished nobility. Central administration directors ultimately appear as a social group at the core of the state, shaped by both generalist and specialist logics, organized around professional bodies and roles, appointments, and career paths. By studying a single function in all its components for the first time, from above and through practices, this research highlights the contributions of the methods used and opens up fruitful avenues for further research into other professional groups and institutions.