ED Mathématiques et Informatique
Deep Wall Models for Aerodynamic Simulations
by Michele ROMANELLI (IMB - Institut de Mathématiques de Bordeaux)
The defense will take place at 14h00 - Ada Lovelace Centre Inria de l'Université de Bordeaux, 200 avenue de la Vieille Tour , 33400 Talence
in front of the jury composed of
- Heloïse BEAUGENDRE - Directrice de recherche - Bordeaux INP - Directeur de these
- Michel BERGMAN - Directeur de recherche - Université de Bordeaux IMB - CoDirecteur de these
- Pierre SAGAUT - Directeur de recherche - Université d'Aix-Marseille - Rapporteur
- Lars DAVIDSON - Professor - Université de technologie Chalmers - Rapporteur
- Camilla FIORINI - Maîtresse de conférences - Conservatoire National des Arts et Métiers - Examinateur
- Raphaël LOUBèRE - Directeur de recherche - Université de Bordeaux IMB - Examinateur
Reynolds-Averaged Navier-Stokes (RANS) simulations are widely used in the industrial domain. However, their accuracy heavily relies on the solution of near-wall flows, typically requiring a very fine mesh to properly capture the steep gradients developing in the boundary layer. This results in a substantial impact on the computational cost of the simulation. Wall laws allow to speed up of these calculations by replacing the costly resolution of the boundary layer with modeling. In this context, deep learning-based approaches are being explored and the flexibility of neural networks offers undeniable potential in modeling near-wall flows. This work aims to develop a wall law based on deep learning that can accurately reproduce the evolution of the internal region of the boundary layer, thereby providing boundary conditions for the RANS calculations occurring far from the wall. A preliminary approach involves training a neural network on wall-resolved data to reconstruct dimensionless velocity profiles and model the evolution of the boundary layer near the wall. In accordance with analytical wall laws, velocity is a function of the distance to the wall and the pressure gradient, with these variables being non-dimensionalized using a characteristic friction velocity, which is iteratively estimated using a Newton-Raphson algorithm. To reduce the cost associated with the iterative estimation of the wall shear stress, a new approach entirely based on deep learning has been developed. It directly imposes the friction at the interface between the modeled region and the RANS calculation, fixing the normal derivative of the velocity field, which is estimated using two interconnected neural networks: one estimating the wall shear stress and the other evaluating the dimensionless normal derivative of the velocity. The neural networks are trained on fully resolved RANS simulations of turbulent flows over various two-dimensional bump geometries. The performance of this wall model, in term of accuracy and computational cost, is then compared to wall-resolved calculations for flow configurations not included in the training dataset.
ED Sciences Chimiques
NONLINEAR OPTICAL PROPERTIES OF MOLECULAR PHOTOSWITCHES: COMPUTATIONAL STUDY OF CHEMICAL SUBSTITUTION, CONFORMATIONAL DYNAMICS AND ENVIRONMENT EFFECTS
by Angela DELLAI (Institut des Sciences Moléculaires)
The defense will take place at 10h00 - ISM Conference Room Bâtiment A12, Université de Bordeaux 351 Cr de la Libération, 33405 Talence
in front of the jury composed of
- Frédéric CASTET - Professor - Université de Bordeaux - Directeur de these
- Miroslav MEDVED - Associate Professor - Matej Bel University in Banska Bystrica - Rapporteur
- Luca MUCCIOLI - Associate Professor - University of Bologna - Rapporteur
- Claire TONNELé - Chargée de recherche - Donostia International Physics Center - Examinateur
- Benoît CHAMPAGNE - Professeur - University of Namur - Examinateur
- Vincent RODRIGUEZ - Professeur - Université de Bordeaux - Examinateur
This thesis focuses on the characterization of the second-order nonlinear optical (NLO) properties of molecular photoswitches by means of computational chemistry. In particular, we implement computational approaches to investigate the second harmonic generation (SHG) process occurring in two families of photoswitches, namely Donor-Acceptor Stenhouse Adducts (DASAs) and azobenzene derivatives (AZOs). The different chapters of the thesis address various aspects influencing the SHG responses of the photoswitches, including their substitution pattern, their conformational dynamics, as well as their surrounding. In a first part, we study the effect of the push-pull character of a series of DASA and AZO derivatives, by functionalizing their extremities with various electron-donating and electron-withdrawing chemical substituents. The NLO responses in solution are calculated using the density functional theory (DFT) on the basis of the equilibrium geometries of the chromophores, and using implicit continuum models for treating solute-solvent interactions. This approach is shown to provide first hyperpolarizability (β) values in good qualitative agreement with the experimental data obtained from Hyper-Rayleigh Scattering (HRS) measurements, allowing reliable structure-property relationships to be established. In a second part, we implement a computational approach combining molecular dynamics simulation (MD) and DFT calculations, in order to include the effects of structural dynamics and a better description of solute-solvent interactions in the NLO responses of the photoswitches. The investigations are conducted on a representative DASA derivative. We first show that the thermalized conformational dynamics enhances the molecular first hyperpolarizability, giving rise to improved agreement with HRS measurements. We also demonstrate that the fluctuations of the β values along the structural dynamics are correlated with the bond order alternation (BOA), which provides a measure of the π-electron conjugation over the molecule. In a second step, we elaborate different computational approaches going beyong the implicit continuum models to improve the description of solute-solvent interactions. In the final part of the thesis, the mixed quantum/classical computational methodology is employed to characterize the NLO responses of self-assembled monolayers (SAMs) functionalized with AZO derivatives, bearing either a donor or acceptor substituent on their external phenyl. Herein, we investigate how the nature of the substituent impacts the spatial organization of the molecular photoswitches within the SAMs, as well as the magnitude of their NLO responses.
Eco-extraction of natural dyes from tinctorial plants
by Alix GOMBERT (Institut de Chimie & de Biologie des Membranes & des Nano-objets)
The defense will take place at 13h30 - AMPHI 1 ENSMAC 16 Av. Pey Berland, 33600 Pessac
in front of the jury composed of
- savoire RAPHAELLE - Professeure - Bordeaux INP - Directeur de these
- Christelle HARSCOAT-SCHIAVO - Chargée de recherche - CNRS - CoDirecteur de these
- Maryline VIAN - Professeure - Université d'Avignon - Rapporteur
- Séverine CAMY - Professeure - Toulouse INP - Rapporteur
- Laurent DUFOSSé - Professeur - Université de La Réunion - Examinateur
- Thierry MAUGARD - Professeur - Université de La Rochelle - Examinateur
- Pierre WAFFO-TéGUO - Professeur - Université de Bordeaux - Examinateur
- Jean-Yves CLAVIER - Docteur - Supercritical Engineering - Examinateur
Dyes are widely used in various sectors (textile, cosmetic, food), and consumers are seeking natural origins for products. The development of synthetic dyes since the beginning of the 20th century has contributed to the decline of dyeing plant cultivation and of the extraction of dye compounds. The current renewed interest in plant-based dyes requires adapting the extraction methods for these plant compounds. Natural dyes are generally extracted by maceration using hydroalcoholic mixtures. Depending on the plant and the extraction conditions, the yields, compositions of the extracts, and colours obtained can considerably vary. The aim of this work is to study the impact of pressurised processes such as supercritical carbon dioxide (SFE) and pressurised solvents (PSE) as well as an intensification process using ultrasound (UAE) on the extraction of natural dyes in terms of yield, extract composition, and the colour obtained in silk dyeing applications. Two plants were studied, considering their local cultivation and the different chemical nature of the dye molecules: madder (Rubia tincorum L.) and weld (Reseda luteola L.). Madder roots contain anthraquinones (alizarin, purpurin, and their glycosides) with pink-red-orange colours, while flavonoids (luteolin, apigenin, and their glycosides) are the yellow dye compounds present in the aerial parts of weld. Whatever the extraction process, overall dry extract yields are similar to those of maceration, at around 33% and 17% for madder and reseda respectively. On the other hand, anthraquinone and flavonoid yields differ according to the process, as do the colouring molecule compositions of the obtained extracts. In the case of madder extracts, this results in variable textile colours ranging from light orange to dark red, while reseda dyes are more or less yellow. It has been shown that the supercritical process is more selective on orange glycosyl compounds in the case of madder. When extracting dyes from reseda, however, SFE leads to extract both chlorophylls and flavonoids, broadening the range of colours obtained by conventional maceration.
Sandwich structures in ceramic matrix composites. Realisation and characterisation, modelling of the thermo-mechanical behaviour.
by Nicolas ABOUAB (Laboratoire des Composites ThermoStructuraux)
The defense will take place at 14h00 - Amphithéâtre LCTS 3 Allée de la Boétie, 33600 Pessac
in front of the jury composed of
- Jérôme Olivier ROGER - Maître de conférences - Université de Bordeaux - Directeur de these
- Monica FERRARIS - Professeure des universités - Politecnico di Torino - Rapporteur
- Olivier CATY - Maître de conférences - ENSEIRB-MATMECA - CoDirecteur de these
- Zoheir ABOURA - Professeur des universités - UTC - Rapporteur
- Federica DAGHIA - Maîtresse de conférences - ENS Paris-Saclay - Examinateur
- Jean-Marc HEINTZ - Professeur - ENSMAC - Examinateur
Ceramic matrix composites (CMC) are high thermo-mechanical resistant materials with relatively low bulk density. They constitutes then prime materials for aeronautic and aerospace applications. Besides, their stiffness could be even further increased by manufacturing them into sandwich structures. However their great hardness makes them difficult to machine and their processing techniques limit the achievable shape complexity. CMC sandwich structure manufacturing thus requires some specific development. These PhD work therefore constitutes a methodological guide for studying T-shape intersections, here considered as the representative elementary architecture of a sandwich structure made of C/SiC. First of all, different approaches for producing intersections are implemented : by assembling finished plates, by folding and co-densifying pieces of fibre fabric, or by 3D weaving of a single piece preform. The first approach lead to the development of an innovative assembling process by non-reactive infiltration (NoRI). The microstructure and the chemical composition of the resulting joint are analysed by SEM, TEM, EDS and Raman spectroscopy. The T-shape intersections produced according to each of the three approaches are furthermure morphologically characterised and compared through X-ray tomography, optic microscopy and porosimetry. Secondly, mechanical characterisation of the investigated intersections, and their constitutive composites and assembly joints, are conducted at room temperature as well as 1200°C thanks to a specific testing equipment developed during this thesis. Thirdly, two methods of mechanical FE modelling are implemented and tested on the T-shape intersections : a homogeneous method where equivalent properties are identified thanks to testing records, and a meso-informed method using meso-structure data obtained by tomography. Extending theses models into the targeted sandwich structure scale is addressed eventually.
DNA-coated two-patch particles as building blocks for programmed assembly
by Auriane BAGUR (ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux)
The defense will take place at 14h00 - Amphi Centre de Recherche Paul Pascal. 115 Avenue du Dr Albert Schweitzer, 33600 Pessac
in front of the jury composed of
- Etienne DUGUET - Professeur - Université de Bordeaux - Directeur de these
- Massimiliano D'ARIENZO - Associate Professor - University of Milano Bicocca - Rapporteur
- Simon TRICARD - Directeur de recherche - INSA Toulouse - Rapporteur
- Alexa COURTY - Professeure - Sorbonne Université - Examinateur
- Jean-Christophe BARET - Professeur - Université de Bordeaux - Examinateur
- Serge RAVAINE - Professeur - Université de Bordeaux - CoDirecteur de these
Colloidal self-assembly is a powerful strategy for materials design. For example, spherical building blocks can form ordered structures such as face-centered cubic and hexagonal close-packed lattices. However, the use of isotropic building units limits the assembly of more complex structures. In contrast, the use of patchy particles allows to achieve control over the directionality of the interaction and the valence of the particles, allowing access to more sophisticated structures through self-assembly strategies. In this work, we have developed two routes to reliably produce two-patch colloidal particles that can self-assemble driven by DNA hybridization. Our first approach focused on the synthesis of silica/polystyrene monopod-like micron-sized particles via seeded dispersion polymerization. The particles consisted of a PS nodule attached to a single silica core and acted as a mask onto the silica surface for the grafting of DNA strands. Then, the physically entangled polystyrene chains were subsequently dissolved. The remaining PS chains grafted at the silica surface were in turn functionalized with different DNA strands, leading to the formation of bi-patch silica particles. This selective and asymmetric functionalization was crucial for controlling the interactions between particles and enabled us to assemble them into dimers and raspberry-like clusters. The second strategy started with bipod-like silica/polystyrene nanoparticles, synthesized via seeded emulsion polymerization. These bipods were composed of a single silica nanoparticle attached to two PS nodules positioned opposite to each other. The bipods were converted into bi-patch particles by dissolving the PS nodules, followed by selective DNA functionalization of the remaining surface PS chains. Morphological analysis by transmission electron microscopy and atomic force microscopy revealed structural changes before and after functionalization. Mixtures of two batches of bi-patch nanoparticles functionalized with complementary DNA strands allowed us to control the formation of one-dimensional assemblies, referred to as “colloidal polymers”. The chain length of these colloidal polymers can be modulated by varying the incubation time.
Spin crossover in self-assembled monolayers: towards switchable molecular devices
by Rebecca RODRIGUES DE MIRANDA (ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux)
The defense will take place at 15h00 - Amphithéatre ICMCB – UMR5026 87, Avenue du Docteur Schweitzer 33600 Pessac
in front of the jury composed of
- Patrick ROSA - Chargé de recherche - ICMCB - Université de Bordeaux - Directeur de these
- Christian A. NIJHUIS - Professeure des universités - Universiteit Twente - Examinateur
- Lorenzo POGGINI - Chargé de recherche - Università degli Studi di Firenze - Examinateur
- Vellutini LUC - Professeur des universités - ISM - Université de Bordeaux - Examinateur
- Anna PROUST - Professeure des universités - Sorbonne Université - Rapporteur
- E. Carolina SAñUDO - Associate Professor - Universitat de Barcelona - Rapporteur
The continual quest for ever-smaller technological components has led to massive research efforts in the fields of molecular electronics and, more recently, spintronics. These components should be simultaneously more powerful and less energy-hungry, and in this context, spin crossover (SCO) molecules have far-reaching potential. These transition metal complexes can be switched between two distinct states by a multitude of stimuli, and exhibit substantial changes in their chemical and physical properties upon switching, giving them many prospective applications. This thesis presents several new iron (II) SCO molecules with a thermal - and in some cases photo-induced - switching that is dependent on the degree of steric hindrance of the ligands. Typically, SCO in monolayers is significantly altered due to molecule-substrate interactions, but the molecules presented in this thesis exhibit a rarely observed non-quenched SCO thanks to an alkyl spacer separating the SCO moiety from the coinage metal substrates. The SCO of the molecules in bulk was followed by magnetometry (vibrating sample magnetometry, VSM, and superconducting quantum interference device, or SQUID, magnetometry), variable-temperature nuclear magnetic resonance (NMR) and Raman spectroscopies, as well as X-ray photoelectron and absorption spectroscopies (XPS and XAS, respectively). The SCO behaviour of the monolayers was characterised by XPS and XAS. Thanks to a flexible synthesis route, these novel molecules can form both self-assembled monolayers (SAMs) and break junctions, depending on the number and nature of the anchoring groups. SAMs have been prepared on ultra-flat gold, silver and copper substrates. The morphology, chemical composition, and packing of these monolayers were characterised by atomic force microscopy (AFM), time-of-flight secondary ion mass spectrometry (ToF-SIMS), XPS semi-quantitative analysis, polarisation modulation infrared reflection absorption spectroscopy (PM-IRRAS), and electrochemistry, supported by density functional theory (DFT) calculations. In order to turn these SAMs into switchable devices, eutectic Gallium Indium (eGaIn) was used as a top electrode. This alloy is a soft and deformable non-Newtonian fluid capable of forming non-damaging contacts with molecules. The electrical properties of large-area molecular junctions were thus measured, initially at room temperature, and then above and below, in order to follow the changes in transport behaviour with temperature. Single molecule junctions were formed using two different methods, both at room temperature: scanning tunnelling microscopy (STM) in solution, and single-walled carbon nanotube nanogap junctions in the solid state. Though the changes in electronic behaviour of the SAMs with temperature could not be conclusively assigned to SCO, this thesis shows that, with some fine-tuning, these systems are feasible as switchable components. The easily tuneable synthesis route gives this family of molecules countless potential applications, and opens up numerous different avenues for future research. The presented molecular junction systems help pave the way towards stable, low-power, multi-addressable, and switchable molecular devices that function at ambient conditions.
ED Droit
Judicial jurisdiction confronted by Third Parties situations. A study of private international law
by Marion SOURICE (INSTITUT DE RECHERCHE EN DROIT DES AFFAIRES ET DU PATRIMOINE)
The defense will take place at 14h00 - Salle Manon Cormier Batiment G 16 avenue Léon Duguit 33608 Pessac
in front of the jury composed of
- Sandrine CHAILLE DE NERE - Professeur des universités - Université de Bordeaux - Directeur de these
- Sarah LAVAL - Professeur des universités - Université Littoral Côte d'Opale - Rapporteur
- Philippe GUEZ - Professeur des universités - Université Paris Nanterre - Rapporteur
- Jean-Sébastien QUEGUINER - Professeur des universités - Université de Rennes - Examinateur
As a result of the complexification and internationalisation of legal relations, private international law is increasingly confronted with the figure of the third party, as illustrated by the development of European case law relating to third parties situations. Although the issues arising from this confrontation have mainly been studied in relation to applicable law, the confrontation of private international law with these situations is a source of many uncertainties which are very present in relation to judicial jurisdiction. The study of judicial jurisdiction from the perspective of third parties raises questions about the ability of the European system to respond in a predictable way to these complex situations, which often have strong national characteristics. In the absence of European substantive law on which to base an autonomous interpretation of the various European rules, their implementation is based on foundations that rarely lead to coherent solutions, despite the far-reaching changes in the case law solutions adopted in application of the Brussels I bis Regulation. The difficulties are mainly focused in the area of obligations, where the dichotomy between contract and tort is undermined by situations that are constantly in the grey area and where the grounds of jurisdiction adopted are difficult to implement because of the peculiar configuration of the disputes. Thus situations involving third parties reveal the conceptual weaknesses of the various European rules, which need to be studied carefully in order to offer ideas on which to build a possible overhaul of the European system of jurisdiction.
The models of constitutional justice : between inedequacy and innovation. Toward a multidimensional analysis of comparative constitutional justice
by Marta AURINO (CENTRE D'ÉTUDES ET DE RECHERCHES COMPARATIVES SUR LES CONSTITUTIONS, LES LIBERTÉS ET L'ÉTAT)
The defense will take place at 13h30 - 1 K 35 Pl. Pey Berland, 33000, Bordeaux
in front of the jury composed of
- Fabrice HOURQUEBIE - Professeur des universités - Université de Bordeaux - Directeur de these
- Caterina SEVERINO - Professeure des universités - Science Po Aix - Rapporteur
- Ines CIOLLI - Professeure associée - Università di Roma La Sapienza - Rapporteur
- Laura CAPPUCCIO - Professeure associée - Università di Napoli Federico II - Directeur de these
- Nicoletta PERLO - Professeure des universités - Université de Bourgogne - Examinateur
- Charles-Édouard SENAC - Professeur des universités - Université de Bordeaux - Examinateur
- Arthur DYEVRE - Professeur associé - KU Leuven - Examinateur
- Alberto LUCARELLI - Professeur des universités - Università degli Studi di Napoli Federico II - Examinateur
This thesis proposes a reassessment of traditional models of constitutional justice through a comparative and empirical approach. The classical distinction between the American and European models, when confronted with the growing diversity of constitutional justice systems worldwide, reveals significant conceptual limitations. To address these challenges, two analytical pathways emerge: one aimed at developing new theoretical models based on revised criteria, and the other focused on creating innovative analytical tools better suited to contemporary complexities. It is this latter, less explored approach that forms the core of this work. Drawing on an empirical analysis of constitutional justice systems globally, and employing correspondence analysis methods, a multidimensional analytical tool has been developed. This tool allows for the representation of the diversity of legal systems in a fluid and evolving framework, accounting for contextual variations and the multiple interactions influencing constitutional litigation. Rather than classifying systems according to fixed criteria, it positions them within an open dynamic, reflecting the complexity of their interactions. The central objective is to better understand the role of the constitutional judge by examining their participation in the decision-making process, with a focus on constitutional review standards, access to justice, and the competencies of Constitutional Courts. By adopting an empirical and multidimensional methodology, this work seeks to transcend traditional frameworks in order to embrace the complexity and multiplicity of contemporary legal realities while creating a didactic tool
illiberalism, neoliberalism's heir or foe? An investigation into the concept of illiberalism
by Raphaël MORISSET (INSTITUT DE RECHERCHE MONTESQUIEU)
The defense will take place at 14h00 - salle des thèses Bâtiment C 16 avenue Léon Duguit 33608 Pessac
in front of the jury composed of
- Patrick TROUDE-CHASTENET - Professeur émérite - Université de Bordeaux - Directeur de these
- Frédérique RUEDA - Professeure des universités - Université de Bordeaux - CoDirecteur de these
- Marlène LARUELLE - Professeure des universités - George Washington University - Rapporteur
- Rafaël COS - Professeur des universités - Université de Bordeaux - Examinateur
- Luca TOMINI - Associate Professor - Université Libre de Bruxelles - Examinateur
- Benjamin BOUDOU - Professeur des universités - Université de Rouen - Rapporteur
The aim of this dissertation is to question the relevance of the concept of illiberalism, in other words, to assess the reliability and usefulness of a concept that is subject to contradictory and rival appropriations at the ideological level. This research takes the form of a survey, which maps the uses of the concept of illiberalism from the 1990s to the present day. In order to clarify the existence of contradictions and misunderstandings in the conceptualisation of illiberalism due to the ‘essentially contested' nature of liberalism, this dissertation defends the use of the theoretical tools of the ‘Wittgensteinian' political theory of Hanna Pitkin and Michael Freeden. The use of this conceptual framework allows us to defend the use of the concept of illiberalism in order to render intelligible the existence of an ‘illiberal ideology', and to describe the continuity between the questioning of liberalism initiated by the « Reagan-Thatcher Revolution » and amplified by the arrival in power of an ethno-nationalist right-wing from the 2010s onwards.
ED Entreprise Economie Société
Essays on the distributional impacts and social acceptability of carbon pricing policy in china.
by Badreddine ABOUFARASSE (BSE - Bordeaux sciences économiques)
The defense will take place at 9h00 - Salle des thèses BSE Université de Bordeaux Avenue Léon Duguit, Bât. H2 33608 PESSAC CEDEX
in front of the jury composed of
- Catherine FIGUIERE - Professeure des universités - Université de Grenoble Alpes - Rapporteur
- Sébastien MARCHAND - Maître de conférences - Université Clermont Auvergne - Rapporteur
- Sébastien LECOCQ - Chargé de recherche - Université de Bordeaux - Examinateur
- Aomar IBOURK - Professeur des universités - Université Cady Ayyad - Examinateur
- Matthieu CLEMENT - Professeur des universités - Université de Bordeaux - Directeur de these
- André MEUNIE - Maître de conférences - Université de Bordeaux - CoDirecteur de these
This dissertation examines the distributional impacts of carbon tax policy and public acceptability of environmental taxation in China. Employing original empirical methodologies and extensive household data, the research offers a comprehensive analysis of the regressive nature of carbon taxation and its broader social implications. The first chapter introduces a non-parametric joint distribution dynamics approach to investigate the co-evolution of income and CO2 emissions across more than 2,700 Chinese counties. The findings challenge the traditional Environmental Kuznets Curve (EKC) by revealing multiple equilibria, particularly a poverty-environment trap where poorer regions are caught in low-income and high emissions cycles. These results call for targeted policy interventions to promote economic growth while reducing emissions, focusing on regional coordination. Chapter two delves into the relationship between poverty, household consumption, and carbon emissions, highlighting the carbon intensity of poverty-stricken households. The chapter identifies five distinct household consumption profiles, offering key insights into the heterogeneous carbon consumption behaviors of poverty-stricken households. The findings underscore the importance of differentiated policy strategies to manage the transition to a low-carbon economy without exacerbating poverty. In the third chapter, the regressive impact of carbon taxation is assessed. The results show that lower-income households bear a disproportionate share of the carbon tax burden, particularly in rural areas. A series of regressivity analyses and the application of Suits and Kakwani indices confirm that carbon taxes exacerbate existing economic inequalities. The analysis calls for targeted compensatory mechanisms, including subsidies and cleaner energy access, to mitigate the tax's regressive effects. The fourth chapter uses micro-simulations to explore the short-run distributional and poverty impacts of energy price changes and carbon tax implementation. The results demonstrate that energy price increases, particularly for electricity and motor fuels, disproportionately affect lower-income households, contributing to regressive welfare effects. A simulated carbon tax, applied at the provincial level and set at USD 50/tCO2, results in significant emissions reductions but also leads to considerable welfare losses for lower-income households. Redistribution of tax revenues through lump-sum transfers and targeted cash transfers provides potential mitigation strategies, though their effectiveness varies. This dissertation contributes to the growing literature on environmental taxation by offering new insights into the complex relationships between carbon emissions, poverty, income inequality, and policy interventions. The findings underscore the critical importance of designing equitable carbon tax policies in China, with attention to both environmental and social justice.
ED Sciences de la Vie et de la Santé
Study of PCSK9 convertase in liver sinusoidal endothelial cells during colorectal carcinoma liver metastasis
by Ander MARTIN SAN SEBASTIAN (BoRdeaux Institute of onCology)
The defense will take place at 10h00 - Salon de grados de medicina Facultad de Medicina y Enfermería UPV/EHU, Barrio Sarriena, s/n, 48940 Leioa, Biscay
in front of the jury composed of
- Cesar Augusto MARTIN PLAGARO - Full professor - University of the Basque Country - Examinateur
- Iñigo MARTINEZ ZUBIAURRE - Full professor - The artic University of Norway - Rapporteur
- Ana Luisa CORREIA - Directrice de recherche - Fundation Champalimaud - Rapporteur
- Valérie DESVERGNES - Directrice de recherche - Université de Bordeaux - Examinateur
- Manuel FUENTES GARCíA - Associate Professor - Universidad de Salamanca / Instituto de Biología Molecular y celular del Cancer - Examinateur
Colorectal cancer (CRC) is a leading cause of cancer-related deaths, mainly due to its high potential for metastasis, particularly to the liver. The liver's direct blood supply from the colon makes it a frequent target for CRC metastasis, worsening patient outcomes. Understanding the molecular mechanisms of this process is essential for developing new therapies. Metastasis is a complex process involving local invasion, entry into the bloodstream, survival in circulation, and eventual colonization in distant organs. One key factor in this process is epithelial-mesenchymal transition (EMT), where cancer cells gain the ability to migrate. In the liver, liver sinusoidal endothelial cells (LSECs) interact with CRC cells, promoting tumor survival, immune evasion, and angiogenesis. Recent research highlights the role of PCSK9, a protein primarily involved in cholesterol metabolism, in cancer progression, particularly CRC metastasis to the liver. PCSK9 has been found to influence several cancer-related processes such as EMT, cell proliferation, and immune evasion. Elevated levels of PCSK9 in CRC suggest that it contributes to metastasis, particularly by influencing LSECs. This study investigates how PCSK9 affects LSECs and facilitates liver metastasis. The hypothesis is that PCSK9, upregulated in LSECs in response to tumor signals, promotes tumor cell adhesion, migration, and growth in the liver. Researchers cultured human and murine LSECs and CRC cell lines, inducing a cancer stem cell-like state in CRC cells. Conditioned media from these CRC cells were used to activate LSECs. The effects of PCSK9 on LSECs were studied using inhibitors and siRNA technology. Key findings include the upregulation of PCSK9 in LSECs when exposed to CRC cell signals, increased proliferation and migration of LSECs in response to PCSK9, and a significant reduction in these processes when PCSK9 was inhibited. The study also identified an interaction between PCSK9 and fatty acid-binding protein 5 (FABP5), which regulates the Wnt/β-catenin pathway, a key driver of cell proliferation and angiogenesis. Inhibiting PCSK9 reduced Wnt/β-catenin activity, thereby limiting LSEC activation. In vivo studies using a murine model confirmed that inhibiting PCSK9, especially through siRNA-loaded nanoparticles targeting LSECs, significantly reduced the size of liver metastases. This supports the therapeutic potential of PCSK9 inhibitors in reducing CRC liver metastasis. In conclusion, this study demonstrates that PCSK9 plays a crucial role in promoting CRC liver metastasis by enhancing LSEC activity. Targeting PCSK9, particularly with nanoparticle-based siRNA delivery, offers a promising therapeutic strategy for CRC patients with liver metastasis. Further research is needed to fully understand PCSK9's role in cancer and explore its clinical potential.
Role(s) of glycerol metabolism in the biology of African trypanosomes
by Mohammad EL KADRI (Microbiologie fondamentale et Pathogénicité)
The defense will take place at 13h30 - L'amphithéâtre de l'ENSTBB 146, rue Léo Saignat - Case 87 33076 Bordeaux Cedex
in front of the jury composed of
- Frédéric BRINGAUD - Directeur de recherche - Université de Bordeaux - Directeur de these
- Keith MATTHEWS - Professeur des universités - University of Edinburgh - Rapporteur
- Annette MACLEOD - Professeure des universités - College of Medical, Veterinary and Life Sciences Wellcome Centre for Integrative Parasitology University of Glasgow - Rapporteur
- Brice ROTUREAU - Directeur de recherche - Trypanosome Cell Biology Unit INSERM U1201 Institut Pasteur - Examinateur
- Najma RACHIDI - Chargée de recherche - Unité de Parasitologie moléculaire et signalisation Institut Pasteur - Examinateur
- Laure BEVEN - Professeure des universités - UMR BFP INRAE Bordeaux-Aquitaine - Examinateur
Trypanosoma brucei, an extracellular parasite responsible for African trypanosomiasis, must adapt to distinct environments in its mammalian hosts and the tsetse fly vector. In the mammalian bloodstream, glucose serves as the primary carbon source, fueling the parasite's central carbon metabolism and ATP production, which supports its rapid growth. Once the parasites reach high cell densities, a quorum-sensing mechanism induces a transition from proliferative slender forms to growth-arrested stumpy forms (stumpy-QS). These stumpy forms help prevent host mortality by limiting parasitaemia and are primed for transmission to the tsetse fly. However, it has been demonstrated that glycerol can effectively replace glucose in feeding the parasite's central carbon metabolism, suggesting a significant role in vivo. This aligns with findings that trypanosomes predominantly reside in the extravascular spaces of tissues such as the skin and adipose tissue, where interstitial glycerol concentrations are 5 to 20 times higher than in plasma. Glycerol is released from adipocytes through both lipolysis and lipolysis-independent processes such as glycolysis, and it has been suggested that trypanosome-induced adipocyte lipolysis may even protect the host against trypanosome infection. Together, these data suggest that interactions between adipocytes and trypanosomes, potentially mediated by glycerol, play a critical role in the parasite's life cycle. This thesis explores the impact of glycerol on bloodstream form (BSF) Trypanosoma brucei. Our findings demonstrated that glycerol induces the differentiation of slender BSF into growth-arrested forms that resemble stumpy-QS, but with enhanced survival. Furthermore, under tissue-like conditions, characterized by glycerol levels between 0.2-0.5 mM and glucose at 4 mM, proliferative intermediate forms were generated, which were capable of differentiating into the insect vector stage (procyclics) and sustaining infections in tsetse flies. Additionally, glycerol extended the lifespan of quorum-sensing-induced stumpy forms, which normally have a limited lifespan of a few days. All these data led us to propose a revised model for transmission, in which quorum sensing-induced stumpy-QS forms protect the host from high parasitaemia, while glycerol from adipocytes induces intermediate-Glyc or long-lived stumpy forms that facilitate transmission to the fly. Another key aspect of my thesis concerns the dissection of the signalling pathway involved in glycerol-induced differentiation. By exploiting the extended lifespan of stumpy-Glyc cells in culture, we selected mutants resistant to glycerol-induced differentiation through extended in vitro culturing in a glycerol-containing medium. Comparative genomic analyses between these mutants and cells grown in glucose, which are sensitive to glycerol-induced differentiation, identified candidate mutations associated with the resistance phenotype. Notably, these mutations were found to affect the protein kinase A regulatory subunit (PKAR), whose role in the signalling pathway was validated. Finally, we explored whether T. brucei can metabolize glycerol secreted by adipocytes even in the presence of excess glucose. To investigate this, we used an in vitro co-culture system using a transwell assay, which allowed us to analyse the interactions between parental and mutant trypanosomes and adipocytes. We examined growth and exometabolome profiles using nuclear magnetic resonance (NMR)-based metabolite profiling, coupled with 13C-labeling to trace specific metabolites. Our data showed that T. brucei efficiently utilized glycerol secreted by adipocytes to support its central carbon metabolism, even when glucose was abundant. Together, these data demonstrated that glycerol is a key player in the biology of Trypanosoma brucei.
Identification of the role of astrocyte-derived extracellular vesicles during basal synaptic transmission and long-term plasticity.
by Rebecca HEKKING (Neurocentre Magendie)
The defense will take place at 14h00 - Salle des conférences de l'Institut François Magendie Institut François Magendie, 146 rue Léo Saignat, 33077 Bordeaux Cedex
in front of the jury composed of
- Aude PANATIER - Directrice de recherche - Université de Bordeaux - Directeur de these
- Carole ESCARTIN - Directrice de recherche - Université Paris-Saclay - Rapporteur
- Christophe LEFEBVRE - Professeur des universités - Université de Lille - Rapporteur
- Cécile MALNOU - Professeure des universités - Université Toulouse III CHU Purpan - Examinateur
- Jean-Christophe DELPECH - Maître de conférences - Université de Bordeaux - Examinateur
Brain function relies on the transfer of information between neurons, which occurs at a subcellular structure called the synapse. Interestingly, the efficiency of a synapse can be modified under certain conditions, potentiating or inhibiting information transfer. Over the past 20 years, astrocytes, a type of glial cells, have been identified as key neuronal partners that are able to regulate synaptic transmission. Several pathways allowing astrocytes to regulate synaptic function have already been elucidated, such as for instance ion clearance, neurotransmitter recycling or release of soluble factors. Another interesting but under-investigated pathway would be through the release of extracellular vesicles. Extracellular vesicles (EVs) are small membrane-bound particles that contain bioactive molecules such as proteins, nucleic acids, and lipids. Most cells release these vesicles which allow them to exchange cellular components with neighbouring -but also sometimes distant- cells. EVs have been linked to many biological processes, such as immune function or spreading of neurodegenerative diseases. Some studies suggest that astrocytes also release EVs, yet it is still unclear whether these astrocyte-derived vesicles are involved in synaptic functions. This thesis aims at elucidating whether astrocyte-derived extracellular vesicles play a key role in the regulation of synaptic transmission and plasticity. To address this question, we have designed two complementary studies. We first isolated astrocyte-derived EVs in vitro in order to investigate their release rate and their content. We have shown on one hand that exposing astrocyte cultures to ATP in vitro leads to an increase in the amount of small EVs released within 30 min of the stimulus. Furthermore, the microRNA content of these vesicles is altered in response to the stimulus. A bioinformatics analysis predicted that the altered EV content could eventually affect signalling pathways involved in synaptic transmission in recipient cells. These changes seem to be induced specifically by ATP, since exposure to the excitatory neurotransmitter glutamate or to the inhibitory neurotransmitter GABA did not modify the amount of small EVs released within 30 min of the stimulation. We also studied the involvement of astrocyte-derived EVs in vivo. To this end, we developed a tool that allows us to inhibit EV release from astrocytes in the adult mouse brain. Our tool uses the Cas9 enzyme, i.e. the well-known molecular scissors that can specifically cut DNA at a chosen locus in order to modify an organism's genome. We used Cas9 to invalidate a gene involved in EV biogenesis, thereby inhibiting small EV release. We specifically implemented the Cas9 system in astrocytes using a custom-designed viral approach. Using this tool, our preliminary data suggest that inhibiting the release of small EVs from astrocytes alters a form synaptic plasticity in the hippocampus of adult male mice. To conclude, our findings suggest that small astrocyte-derived extracellular vesicles could indeed be involved in the regulation of some forms of synaptic plasticity and will hopefully encourage further studies to understand the underlying mechanisms.
Research on the molecular markers of bitterness in dry and sweet white wines. Molecular interpretation and practical applications
by Tom ESTIER (Oenologie)
The defense will take place at 14h00 - Amphithéâtre Institut des Sciences de la Vigne et du Vin - 210 chemin de Leysotte 33140 Villenave d'Ornon
in front of the jury composed of
- AXEL MARCHAL - Professeur - Université de Bordeaux - Directeur de these
- Guyot SYLVAIN - Directeur de recherche - Unité INRAE 1268 BIA - Rapporteur
- Séverine DERBRé - Professeure - Université d'Angers - Rapporteur
- Mehdi BENIDDIR - Professeur - Université Paris-Saclay - Examinateur
- Stéphane QUIDEAU - Professeur - Université de Bordeaux - Examinateur
- Eric FRéROT - Distinguished Scientist - DSM Firmenich - Examinateur
In white wines, sweetness and sourness are usually the two poles balancing the taste properties. However, the bitter flavour can sometimes disturb this balance, potentially reducing the quality and value of the wines. Knowledge about the molecular origin of this flavour in white wines is insufficient, and empirical observations linked to the perception of bitterness during the winemaking or aging of white wines suggest the existence of still-unknown molecular markers. The first focus of this work was to examine the current existing knowledge regarding the bitterness of white wines by investigating the influence of a selection of the most described bitter molecules on the taste balance of these wines. The combined use of sensory analysis methods and quantification by LC-HRMS revealed that these compounds had a moderate individual effect but appeared to contribute to the bitterness of white wines through perceptual interactions. Subsequently, the implementation of a fractionation protocol guided by gustatometry from dry and sweet white wines characterized by bitter notes, allowed the purification of ten bitter compounds. In parallel, the development of an LC-HRMS untargeted metabolomics approach coupled with multivariate statistical analysis methods enabled the identification of new markers and the study of their impact on the taste of wines. These results paved the way for improving the laboratory's dereplication performance through the construction of a spectral database from more than 200 non-volatile wine compounds. This database was used for untargeted differential analyses, focused on the effect of dry wines fining and sweet wines bottle aging on their chemical composition in relation to bitterness. Finally, throughout this work, the impact of different viticultural and oenological parameters on the concentrations of known bitter compounds and newly identified markers was studied to clearly identify practices linked to the management of bitterness in white wines.
ED Sciences Physiques et de l'Ingénieur
Software Maintainability Model Based on Static Analysis of the Code Property Graph
by Sébastien BERTRAND (Laboratoire de l'Intégration du Matériau au Système)
The defense will take place at 13h45 - Le petit amphi (O-108) Ecole Nationale Supérieure de Cognitique (ENSC-Bordeaux INP) 109, Avenue Roul, 33405 Talence
in front of the jury composed of
- Jean-Marc ANDRE - Professeur des universités - Université de Bordeaux - Directeur de these
- Olivier BARAIS - Professeur des universités - Université de Rennes - Rapporteur
- Laurent CHAUDRON - Professeur des universités - Theorik-Lab - Rapporteur
- Benoit LE BLANC - Professeur des universités - Université de Bordeaux - Examinateur
Context. The high cost of software maintenance is a major challenge in software engineering. Maintainability is an intrinsic quality corresponding to the ease with which software can be modified, and it plays a crucial role in reducing these maintenance costs. Evaluating maintainability is complex. Although it is an emergent property of the objective structure of the source code, its evaluation is subjective, as it depends on developers and the context. Aim. We aim to establish how to evaluate software maintainability through static code analysis in order to identify the fundamental structural quantities that characterize it. Indeed, current maintainability models tend to reduce maintainability to a single score based solely on software metrics (such as the number of lines or predicates). However, these metrics are often poorly defined and only partially reflect the structure of the code. Approach. We chose to represent the source code of programs in the form of code graphs, as we believe it is an ideal, comprehensive, and underutilized representation for the static analysis of program structure. We then formalized the metrics through declarative queries on the graphs. Finally, we replicated and extended a study by Schnappinger et al. to validate our approach and study the problem of maintainability prediction, particularly the influence of size on prediction. Results. As part of this work, we developed Javanalyser, an open-source tool that automatically generates code graphs by syntax analysis of Java programs. We then formalized 33 static metrics that successfully allowed us to replicate the study of Schnappinger et al. The extension of the study confirmed the strong influence of size on metrics and maintainability, even though other metrics also play a significant role. All our work, data, and code are published under an open-source license. Conclusions. Our work has demonstrated the potential of code graphs for analyzing the structure of industrial Java programs. Based on these graphs, we propose a generalization of existing metrics to better represent this structure. We then construct a multi-dimensional maintainability model capable of adapting to the variability of developers. Future research involve experimentally validating our proposals and exploring the possibilities of an automated discussion with developers.
ED Sociétés, Politique, Santé Publique
Post-Traumatic Stress Disorder and Complex Post-Traumatic Stress Disorder among LGBTQIA+ individuals : Prevalences and associated factors.
by William PERAUD BERTHELOT (Laboratoire de Psychologie)
The defense will take place at 14h15 - Amphithéâtre Gintrac Université de Bordeaux, 3ter Place de la Victoire, 33000 Bordeaux.
in front of the jury composed of
- Bruno QUINTARD - Professeur des universités - Université de Bordeaux - Directeur de these
- Elodie CHARBONNIER - Maîtresse de conférences - Université de Nîmes - Rapporteur
- Olivier VECHO - Maître de conférences - Université Paris Nanterre - Rapporteur
- Nicole RASCLE - Professeure des universités - Université de Bordeaux - Examinateur
Title : Post-Traumatic Stress Disorder and Complex Post-Traumatic Stress Disorder among LGBTQIA+ individuals : Prevalences and associated factors Abstract : Context: LGBTQIA+ individuals make up 9% of the population (IPSOS, 2023). The LGBTQIA+ acronym encompasses people with diverse profiles regarding their sexual orientation, gender identity, anatomical characteristics, or, more broadly, their relationship to heterosexual and cisgender norms. LGBTQIA+ individuals gather the main risk factors for developing Post-Traumatic Stress Disorder (PTSD) or Complex Post-Traumatic Stress Disorder (C-PTSD). Method: The first article establishes the translation and cross-cultural validation of the International Trauma Questionnaire (ITQ; Cloitre et al., 2018), a self-report questionnaire that assesses PTSD and C-PTSD symptoms according to the criteria of the Eleventh International Classification of Diseases (ICD-11). The second article is a systematic literature review aimed at collecting prevalence data on PTSD and C-PTSD in LGBTQIA+ individuals and identifying factors associated with PTSD and C-PTSD symptoms. The third article is a standardized study conducted in France among the general adult population, including LGBTQIA+ individuals, to compare exposure to violence, its traumatic impacts (PTSD, C-PTSD), and explore factors that may influence traumatic symptoms. Discussion: The results of this doctoral research emphasize that considering exposure to violence in LGBTQIA+ individuals is a public health issue. It is now essential to support existing actions and propose new prevention and care measures for the benefit of these individuals. Keywords: LGBTQIA+; Post-Traumatic Stress Disorder; Complex Post-Traumatic Stress Disorder; Violence Exposure; ICD-11 ; Sexual and gender minorities
Deciphering the molecular signature of covert cerebral small vessel disease (cSVD) with a focus on multi-omics biomarkers
by Ilana CARO (Bordeaux Population Health Research Center)
The defense will take place at 14h00 - Amphithéâtre PA Louis, ISPED Amphithéâtre PA Louis, ISPED, 146 rue Léo Saignat, 33076 Bordeaux cedex
in front of the jury composed of
- Stéphanie DEBETTE - Professeure des universités - praticienne hospitalière - Université de Bordeaux - Directeur de these
- Emmanuelle GéNIN - Directrice de recherche - Génétique Génomique fonctionnelle et Biotechnologies - GGB (UMR 1078), Université de Bretagne Occidentale - Rapporteur
- Hans Jörgen GRABE - Professor - University Medicine Greifswald; German Center for Neurodegenerative Diseases (DZNE), Site Rostock/Greifswald - Rapporteur
- Cécilia SAMIERI - Directrice de recherche - Bordeaux Population Health research center (BPH) U1219 - Université de Bordeaux - Examinateur
- Monique BRETELER - Professor - Population Health Sciences, German Center for Neurodegenerative Diseases (DZNE) - Examinateur
- Thierry COUFFINHAL - Professeur des universités - praticien hospitalier - Biologie des maladies cardiovasculaires, U1034, Université de Bordeaux, INSERM - Examinateur
Covert cerebral small vessel disease (cSVD) is extremely common in the general population with increasing age and represents the leading vascular contribution to cognitive decline and dementia including Alzheimer disease (AD). Thus, cSVD represents a major opportunity to detect pre-diagnosis disturbances and prevent those conditions. cSVD is driven by a mix of genetic and environmental factors. However, the underlying mechanisms of cSVD are unknown and molecular biomarkers unavailable. Thus, capturing the impact of genetic, epigenetic and environmental factors using high-throughput technologies may lead to the identification of novel biomarkers and new insights into the pathogenesis of cSVD. These have the potential to contribute to rapid applications for routine research or clinical practice given ease of access and low cost. The objective is to identify biomarkers of cerebral small vessel disease and provide new insights into cerebral small vessel disease pathogenesis and its contribution to dementia and AD using cutting-edge multiomics approaches including proteomics, miRNA and epigenomics. Leveraging rich omics data from large population-based cohort studies this project is articulated around the 3 following main axes: (i) Identifying miRNAs and sncRNAs associated with cSVD (ii) Identifying proteins associated with cSVD (iii) Deciphering an epigenomics signature of cSVD The research conducted during this thesis will allow a better understanding of the mechanisms underlying cSVD leading to cognitive decline, dementia and AD. This will generate novel easy-access circulating biomarkers for cSVD detection and prognostic stratification, by facilitating the identification of individuals at high risk for better prevention of cSVD progression and complications in the population. It also has a strong potential to reveal novel biological pathways of cSVD and decipher underlying molecular mechanisms that could reveal novel biotargets of cSVD.
The action and public inaction of the State of Senegal in relation to migration to Europe. Evaluative analysis based on the emigration of Senegalese in France, Spain and Italy
by Abdoulaye FATY (Les Afriques dans le Monde)
The defense will take place at 14h30 - Visioconférence totale
in front of the jury composed of
- Jean-Noël FERRIE - Professeur des universités - Université de Bordeaux - Directeur de these
- Ismaila Madior FALL - Professeur des universités - Université Cheikh Anta Diop de Dakar - CoDirecteur de these
- Mamadou BADJI - Professeur des universités - Université Cheikh Anta Diop de Dakar - Examinateur
- Yousrabi ABOURABI - Professeure associée - Université Internationale de Rabat - Examinateur
- Ali BENSAAD - Professeur des universités - Université Paris 8 - Rapporteur
- Doudou Dieye GUEYE - Professeur - Université Assane Seck de Ziguinchor - Rapporteur
The objective of this thesis is to better understand Senegal's migration policy with the particular concern of taking a critical look at the way in which the Senegalese authorities try to both respond to European demands - in exchange for relatively more funds to reduce migratory flows while avoiding blocking these flows which have an economically and socially recognized contribution to the stability of the country. Indeed, we note a contradiction between the two demands of which the State of Senegal adopts the "theory of blame avoidance". In other words, the weight of public opinion on public decisions on both sides should not be underestimated. As evidenced by the negotiations on readmission agreements which are progressing slowly in Senegal 9%. This work states and validates two following interpretative hypotheses. First, bilateral and/or multilateral cooperation is rather, for Senegal, a strategy for capturing resources (Transfer of funds from international migrants, Emergency Trust Fund, Official Development Assistance, Foreign Direct Investments), in other words that the State's decisions are based on a one-stop shop logic; Then, the "sprinkled" public responses do not constitute structural and effective measures in the face of the expectations of migrants and candidates for emigration as well as its strategic partners such as the EU and destination countries. Also, we should specify that we have chosen process tracing, which is recognized today as a research protocol in political science, particularly in qualitative analyses of public policies. Using this method, we will analyze the processes, decision sequences and major events to understand the attitude of the State of Senegal, the influence of the expectations of the different networks of actors involved.
The relationship to voting and politics of the cohorts born and socialised in democracy : new civic cultures ?
by Lucas ORMIERE (Centre Emile Durkheim)
The defense will take place at 14h00 - Salle Copernic Sciences Po Bordeaux 11 Allée Ausone 33600 PESSAC
in front of the jury composed of
- Vincent TIBERJ - Professeur des universités - Sciences Po Bordeaux - Directeur de these
- Héloïse NEZ - Professeure des universités - Université Paris-Cité - Département sciences sociales de l'Institut des humanités, sciences et sociétés - Rapporteur
- Jean-Yves DORMAGEN - Professeur des universités - Université de Montpellier - Faculté de Droit et de Science politique - Rapporteur
- Guillermo CORDERO GARCÍA - Professeur des universités - praticien hospitalier - Universidad Autónoma de Madrid - Facultad de Derecho - Departamento de Ciencia Política y RR.II - CoDirecteur de these
- Carolina GALAIS - Professeure associée - Universitat Autònoma de Barcelona - Campus de Bellaterra -Departament de Ciència Política i Dret Públic. - Examinateur
- Sophie DUCHESNE - Directrice de recherche - Sciences Po Bordeaux - Examinateur
This thesis proposes to study the relationship to voting in Spain of cohorts born and socialised in a democracy, in order to compare them with their elders. The existing literature has not examined the differences of electoral cultures between these ‘newcomers', the generations of the Transition and the older generations. All too rarely, the analysis has been based on age rather than cohorts and a longitudinal approach. Yet international research points to the responsibility of the younger generations in the decline of electoral participation in Western democracies (Blais et al., 2004; Blais & Rubenson, 2013). Spain is an exception, however, because unlike the other democracies, voter turnout in first-order elections has hardly declined at all. This is paradoxical, since it could have been postulated that these ‘critical generations' (Lorente & García-Albacete, 2019, 2021), who were less religious and less secure during the Great Recession, should have abstained even more than their counterparts in other countries. This thesis proposes to solve this conundrum using mixed methods. Firstly, we carry out a longitudinal study using post-election surveys conducted by the Centro de Investigaciones Sociológicas between 1979 and 2024. Several aspects of the cohorts' “voting cultures” are analysed: 1.) inter- and intra-generational inequalities in general and second-order elections (European elections and national referendums) since 1979; 2.) the perception of voting as a “civic duty” from 1980 to 2019, the acceptability of abstention (in 1990 and 2005), and declared voting habits “in general” and according to the type of election. Several logistic regressions and additional general mixed models (GAMMs) are used to distinguish age, period and cohort effects, the ‘Gordian knot' of APC methods (Bell, 2020). Then, to expand on the results of the quantitative analysis, we questioned the voting perceptions of members of the various cohorts, through a campaign of 46 semi-structured interviews. These cohorts, born and socialised in a democracy, have developed a different voting culture to their elders, who were socialised during the Transition, Francoism and the Civil War. Their turnout remains high at general elections, and is higher than that of new generations in other Western democracies. The Great Recession has led to a high degree of politicisation. However, their voting is more irregular and fluctuates according to the intensity of election campaigns and the type of elections. Their abstention becomes more widespread during second-order elections. What's more, intra-generational inequalities based on educational level and social class are much greater among them than in previous generations. 6 These results can also be explained by the individualisation of their voting behaviour, which has already been observed in other countries. These cohorts, particularly those most interested in politics and with the highest levels of education, are fully committed to a citizenship of ‘right' voting, which is a far cry from the citizenship of ‘duty' of the cohorts socialised under the Transition and Franco. These results underline the importance of the role of political parties and the media in mobilising these ‘new' citizens to vote, whose representations and expectations of voting are different from those of other generations.