ED Mathématiques et Informatique
Distributed algorithms and local structures in graphs
by Timothé PICAVET (LaBRI - Laboratoire Bordelais de Recherche en Informatique)
The defense will take place at 14h00 - AMPHI LaBRI, 351, cours de la Libération F-33405 Talence cedex
in front of the jury composed of
- Cyril GAVOILLE - Professeur - Université de Bordeaux - Directeur de these
- Marthe BONAMY - Directrice de recherche - Université de Bordeaux, CNRS - CoDirecteur de these
- Maria CHUDNOVSKY - Professor - Princeton University - Examinateur
- Nicolas BOUSQUET - Chargé de recherche - Université Lyon 1 - Rapporteur
- Jean-François MARCKERT - Directeur de recherche - Université de Bordeaux - Examinateur
- Nati LINIAL - Professor - The Hebrew University of Jerusalem - Examinateur
- Christoph LENZEN - Professor - Max-Planck-Institut für Informatik - Rapporteur
In this thesis, we study constant-time distributed algorithms in the LOCAL model, that is, algorithms whose number of rounds is independent of the number of vertices, applied to the approximation of domination problems within various graph classes. We provide approximation algorithms for MDS on parameterized graph families whose approximation factor does not depend on the parameter. First, we prove that a LOCAL algorithm that produces a good approximation on planar graphs can be transformed into a LOCAL algorithm that produces a good approximation on graphs embeddable in a surface of Euler genus. Building on the algorithm of Heydt et al., we derive a (34+ε)-approximation for bounded-genus graphs. This result significantly improves the previous state of the art, namely the 24g+O(1) bound established by Amiri et al., as well as the 91+ε factor obtained by Czygrinow et al. in the particular case of orientable surfaces. We then generalize this result in two directions: first, by considering other graph problems studied in distributed algorithms, and second, by extending our results to graph classes beyond bounded genus. We prove these results through a series of meta-theorems concerning certain minimization problems. Second, we show that certain structured graphs (namely those excluding a minor H of pathwidth at most 2), admit a deterministic distributed algorithm running in f(H) rounds that computes a 50-approximation for the MDS problem. Although fast distributed approximation algorithms for these problems were already known for H-minor-free graphs, all of them had an approximation factor depending on H. A new key ingredient in the analysis of these various distributed algorithms is the use of asymptotic dimension, a geometric notion introduced by Gromov in 1993.
ED Entreprise Economie Société
CSR as a driver of organizational citizenship behaviors : contributions of employer brand and organizational trust.
by Haifa BOURAS (IRGO - Institut de Recherche en Gestion des Organisations)
The defense will take place at 9h30 - C107 PUSG - Université de Bordeaux C104 35 avenue Abadie 33072 Bordeaux
in front of the jury composed of
- Laïla BENRAISS-NOAILLES - Professeure des universités - Université de Bordeaux - Directeur de these
- Catherine VIOT - Professeure des universités - Université de bordeaux - CoDirecteur de these
- André LE ROUX - Professeur des universités - IAE de Poitiers - Rapporteur
- Ewan OIRY - Professeur des universités - IAE de Lyon - Université Jean Moulin Lyon 3 - Rapporteur
- Marc VALAX - Professeur des universités - IAE Nice Université Côte d'Azur - Examinateur
- Julien CUSIN - Professeur des universités - Université de Bordeaux - Examinateur
Organizational citizenship behaviors are an important element in improving organizational efficiency and performance (Podsakoff et al., 1997; Podsakoff and Mackenzie, 2014). In our study, we focus on the concept of corporate social responsibility (CSR), which is a key factor enabling employees to adopt these behaviors (Thomas and Albishri, 2024; Winarno et al., 2024). Furthermore, a company perceived as socially engaged and responsible benefits from a strong employer brand (Jones, 2014; Kim and Park, 2023; Khan et al., 2024) ; this allows it to attract talent and boost the engagement of existing employees. Moreover, the employer brand, by forging a distinct brand image, along with organizational trust, can play a key role in strengthening this relationship. In this study, we will explore the roles of employer brand and organizational trust in the relationship between perceived CSR and organizational citizenship behaviors. To do so, we will begin with an exploratory qualitative study of knowledge workers, specifically engineers working in France. Following this, we will conduct a quantitative study with the same population but on a larger sample, in order to generalize the results and test the effects between variables.
ED Sciences de la Vie et de la Santé
Deciphering Sézary Syndrome tumoral heterogeneity through bioinformatic approach
by Nasir Mahmood ABBASI (BoRdeaux Institute of onCology)
The defense will take place at 14h00 - Bâtiment CARF (ex-CGFB) - Salle de Conférence 146 Rue Léo Saignat, 33000 Bordeaux
in front of the jury composed of
- Solène EVRARD - Professeure des universités - praticienne hospitalière - Université de Toulouse - Rapporteur
- Antonin MARCHAIS - Chargé de recherche - Université Paris-Sud, Orsay - Rapporteur
- Laurence LAMANT - Professeure des universités - praticienne hospitalière - Université de Toulouse - Examinateur
- Domitille CHALOPIN - Maîtresse de conférences - Université de Bordeaux - Examinateur
- Audrey GROS - Professeure des universités - praticienne hospitalière - Université de Bordeaux - Directeur de these
- Slim KARKAR - Maître de conférences - Université de Bordeaux - CoDirecteur de these
Abstract Sézary Syndrome (SS) is a rare and aggressive leukemic variant of cutaneous T-cell lymphoma (CTCL), characterized by the presence of circulating clonal CD4⁺ T lymphocytes. While transcriptional heterogeneity has been extensively studied in patient samples, multi-omic characterization of patient-derived cell line models has remained limited due to the lack of cell lines faithfully recapitulating the molecular and phenotypic features observed in patients. Single-cell multi-omic profiling, including transcriptomics, surface protein quantification, and analysis of T-cell receptor diversity and clonal expansion, was performed across seven cell lines derived from three patients with SS. This approach confirmed substantial heterogeneity within SS cell lines at both the transcriptional and metabolic levels. We also sought to characterize the phenotype and functional state of Sézary cells, revealing Th1, Th2, or Treg-like depending on the cell line. As conventional annotation methods did not allow precise phenotypic definition, a pseudotemporal trajectory analysis based on a reference of CD4⁺ T cells from healthy donors showed that Sézary cells span the CD4⁺ T-cell differentiation continuum, encompassing naïve, TCM, and TEM/Temra states. Transcription factor analysis identified three dominant regulatory states: an inflammatory/survival program associated with NF-κB/AP-1, a proliferative state associated with MYC/E2F with consistent downregulation of FOXO1, and an interferon response state (IRF1, STAT2). Differential gene expression analysis revealed upregulation of genes involved in metabolism and proliferation (SLC25A5, COX5A, GTSF1, YWHAH, and CLIC1) and downregulation of immune signaling genes (FOXP1, CD247, and IL7R), as well as negative regulators of T-cell proliferation and survival (PIK3IP1, TXNIP, RASA3, and several ZFP family members) in Sézary cells. Notably, CLIC1 (Chloride Intracellular Channel 1), encoding a membrane chloride channel involved in redox homeostasis, proliferation, and cell survival, was consistently overexpressed across all cell lines compared to normal CD4⁺ T cells. In vitro pharmacological inhibition using IAA-94 reduced cell growth, supporting a functional role for CLIC1 in redox homeostasis and cell survival. Ligand-receptor analysis identified recurrent chemokine-mediated interactions, notably involving the CCL5–CCR4 axis, as well as consistent CXCL10-associated signaling. These results demonstrate that the tumor heterogeneity previously described in primary patient samples is preserved in vitro, confirming the relevance of these cell lines as models for functional studies. Finally, CLIC1 overexpression and its involvement in tumor biology suggest that its inhibition may represent a promising therapeutic strategy in Sézary syndrome.
ED Sociétés, Politique, Santé Publique
Investigating the role of interoception in the comorbidity between pain and post-traumatic stress disorder: a process-oriented analysis and evaluation of a trauma-informed interoceptive intervention, Trauma Center Trauma-Sensitive Yoga
by Maria ZWIENENBERG (Laboratoire de Psychologie)
The defense will take place at 13h00 - salle Dénucé Université de Bordeaux (Victoire campus) 3ter Pl. de la Victoire, 33000 Bordeaux
in front of the jury composed of
- Greg DECAMPS - Professeur des universités - Université de Bordeaux - Directeur de these
- Marie-Jo BRENNSTUHL - Maîtresse de conférences - Université de Lorraine - Examinateur
- Luisa WEINER - Professeure des universités - Université de Strasbourg - Rapporteur
- Michèle KOLECK - Professeure des universités - Université de Bordeaux - Examinateur
- Aurélie UNTAS - Professeure des universités - Université Paris Cité - Rapporteur
Background Chronic pain and posttraumatic stress disorder (PTSD) frequently co-occur and represent a major public health concern. This comorbidity is associated with heterogeneous clinical presentations, involving complex interactions between physical, emotional, and relational factors. In this context, interoception—defined as the perception and interpretation of internal bodily signals—appears to be a key process for understanding the mechanisms underlying both chronic pain and posttraumatic stress, including its complex forms. However, its multidimensional nature remains insufficiently characterized in these populations, and few interventions specifically targeting interoceptive processes have been developed. Accordingly, the present thesis aimed to examine the role of interoceptive processes in the comorbidity of chronic pain with PTSD and complex PTSD (CPTSD) and to evaluate an interoceptive, trauma-sensitive intervention. Methods First, a systematic review was conducted to synthesize current knowledge on the links between early trauma, PTSD/CPTSD, and chronic pain, and to inform the design of subsequent empirical studies. Drawing on a tertiary care sample from a specialized pain clinic, a cluster analysis was then conducted to identify clinical profiles of patients with chronic pain based on traumatic symptoms, and to describe their sociodemographic, medical, and trauma-related characteristics, as well as interoceptive sensibility and pain-related outcomes. A second study examined associations between interoceptive dimensions and PTSD/CPTSD symptoms using hierarchical regression models adjusted for clinical and sociodemographic covariates. Finally, an exploratory intervention study assessed the acceptability, preliminary effects, and perceived changes associated with Trauma Center Trauma-Sensitive Yoga (TCTSY), using both quantitative pre–post measures and qualitative analyses within a clinical sample, including patients with traumatic distress interfering with standard pain management. Results Cluster analyses revealed four distinct clinical profiles characterized by differing levels of traumatic symptomatology, interoceptive sensibility, emotional distress, and exposure to violence. Regression analyses showed specific associations between certain interoceptive dimensions (emotional awareness, body listening, body trust, and not-worrying) and traumatic symptoms, which varied across PTSD and complex PTSD dimensions. The TCTSY intervention was well accepted and associated with improvements in these interoceptive dimensions, particularly among chronic pain patients with comorbid traumatic stress, compared to those with significant psychological distress without prominent traumatic symptoms. Qualitative findings highlighted broader changes in participants' relationship to pain and their bodies, as well as improvements in their sense of self in everyday life, particularly through an enhanced sense of agency. Discussion These findings highlight the relevance of an integrative approach linking chronic pain, psychological trauma, and interoception, and underscore the central role of interoceptive processes in this comorbidity. They contribute to refining current conceptual models—often centered on PTSD—by situating them within a predictive processing framework and incorporating the specificities of CPTSD. The results also support the relevance of trauma-sensitive interventions targeting interoceptive exposure processes, such as TCTSY, particularly in clinical settings not specialized in trauma, where trauma-related processes may nevertheless interfere with standard care.