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The Dehn Twist Action for Quantum Representations of Mapping Class Groups
No full text20 pages, 2 figuresInternational audienceWe calculate the Dehn twist action on the spaces of conformal blocks of a not necessarily semisimple modular category. In particular, we give the order of the Dehn twists under the mapping class group representations of closed surfaces. For Dehn twists about non-separating simple closed curves, we prove that this order is the order of the ribbon twist, thereby generalizing a result that De Renzi-Gainutdinov-Geer-Patureau-Mirand-Runkel obtained for the small quantum group. In the separating case, we express the order using the order of the ribbon twist on monoidal powers of the canonical end. As an application, we prove that the Johnson kernel of the mapping class group acts trivially if and only if for the canonical end the ribbon twist and double braiding with itself are trivial. We give a similar result for the visibility of the Torelli group
Representability of G-functions as rational functions in hypergeometric series
No full textAccepté dans le Bulletin des sciences mathématiquesInternational audienceFres\'an and Jossen have given a negative answer to a question of Siegel about the representability of every -function as a polynomial with algebraic coefficients in -functions of type with , and rational parameters . In this paper, we study, in a more general context, a similar question for -functions asked by Fischler and the second author: can every -function be represented as a polynomial with algebraic coefficients in -functions of type with , rational parameters and algebraic over with ? They have shown the answer to be negative under a generalization of Grothendieck's Period Conjecture and a technical assumption on the~'s. Using differential Galois theory, we prove that, for every , there exists a -function which can not be represented as a rational function with coefficients in of solutions of linear differential equations with coefficients in and at most singularities in . As a corollary, we deduce that not all -functions can be represented as a rational function in hypergeometric series of the above mentioned type, when the 's are rational functions with degrees of their numerators and denominators bounded by an arbitrarily large fixed constant. This provides an unconditional negative answer to the question asked by Fischler and the second author for such~'s
Projet Collectif de Recherche « Juliobona, capitale des Calètes ». Résultats de l’année 2024. Rapport d’opération
No full textOptimizing Predictive Maintenance in Vehicular Systems via Positive Influence Dominating Sets
No full textInternational audienceModern vehicular systems consist of interconnected components forming complex networks of dependencies. Failures in one component can propagate to others, creating significant challenges for predictive maintenance. Addressing these challenges requires strategies that balance inspection costs with system reliability. This paper introduces an approach based on graph theory to model the dependency relationships between the engine components. By utilizing the Positive Influence Dominating Set (PIDS) concept, we identify critical components whose maintenance ensures comprehensive system coverage. Several algorithms are evaluated over the proposed model, examining trade-offs between accuracy and computational efficiency. The results provide valuable insights into algorithm selection and demonstrate the model's potential to optimize maintenance scheduling for complex vehicular systems
Phylogeny of Arbacia Gray, 1835 (Echinoidea) reveals diversification patterns in the Atlantic and Pacific Oceans
No full textInternational audienceAim : The aim of the current study is to conduct a comprehensive phylogenetic analysis of the genus Arbacia to elucidate the evolution and phylogenetic relationships among all extant species and reevaluate the presence of geographic structure within species that have wide, fragmented distributions.Location : Specimens of Arbacia were collected from 34 localities spanning the Atlantic and Pacific Oceans, and the Mediterranean Sea.Methods : We obtained sequences from three mitochondrial markers (COI, 16S and the control region and adjacent tRNAs) and two nuclear markers (28S and 18S; the latter ultimately excluded from the final analyses). Phylogenetic trees were constructed using maximum likelihood and Bayesian inference approaches. A time‐calibrated phylogenetic tree was inferred using a relaxed Bayesian molecular clock and three fossil calibration points.Results : Our analysis supports the monophyly of the genus Arbacia , including the species Arbacia nigra (previously assigned to the monotypic genus Tetrapygus ). The new phylogenetic topology suggests an alternative biogeographic scenario of initial divergence between Atlantic and Pacific subclades occurring approximately 9 million years ago. The dispersal and subsequent diversification of the Pacific subclade to the southeast Pacific coincides with the onset of glacial and interglacial cycles in Patagonia. In the Atlantic subclade, the split between A. punctulata and A. lixula occurred 3.01–6.30 (median 3.74 million years ago), possibly associated with the strengthening of the Gulf Stream current connecting the western and eastern Atlantic. Our study also reveals significant genetic and phylogeographic structures within both Atlantic species, indicating ongoing differentiation processes between populations.Main Conclusion : Our study provides valuable insights into the evolutionary history and biogeography of the genus Arbacia and highlights the complex interplay between historical climate changes and oceanic currents in shaping the distribution and diversification of echinoids in the Atlantic and Pacific Oceans
Using the NanoBioAnalytical (NBA) Platform to Decipher Extracellular Vesicles Secreted by Microvascular Endothelial Cells Under Benzo[a]pyrene Exposure
No full textInternational audienceRecent advances in the clinical extracellular vesicles (EVs) field highlight their potential as biomarkers for diverse diseases and therapeutic applications. This study provides an in-depth characterization of 10k EVs from human microvascular endothelial cells (HMEC-1) exposed to benzo[a]pyrene (B[a]P), a polycyclic aromatic hydrocarbon found in food and smoke. Given EVs’ complexity, with numerous surface and cargo proteins, phenotyping remains challenging. Here, we introduce a multiplex biosensor, in µarray format, for profiling EVs from distinct cellular conditions, employing a multimodal approach that combines surface plasmon resonance imaging (SPRi) and in situ atomic force microscopy (AFM) to decipher EVs’ biochemical and biophysical properties. SPRi experiments showed notable EV capture differences on ligands such as Anti-CD36, Anti-CD81, and Anti-ApoA between treated and control conditions, likely due to B[a]P exposure. A complementary AFM study and statistical analyses revealed size differences between EVs from treated and control samples, with ligands like Annexin-V, Anti-CD36, and Anti-VEGFR1 emerging as ligands specific to potential cytotoxicity biomarkers. Our findings suggest that B[a]P exposure may increase EV size and alter marker expression, indicating phenotypic shifts in EVs under cytotoxic stress. The original combination of SPRi and AFM reveals valuable data on the phenotypical and morphological heterogeneities of EV subsets linked to cytotoxic stresses and highlights the potential of EVs as specific toxicological markers
Bone mineral density in French adults with early-treated phenylketonuria
No full textInternational audiencePhenylketonuria (PKU) treatment requires a low-phenylalanine (Phe) diet limiting natural protein intake, using medical low-protein foods and Phe-free amino acids (AA) supplements along with micronutriments' supplies. Current recommendations suggest maintaining this diet for life to prevent neuro-psychological effects of high Phe concentrations. The long-term consequences of such a diet are poorly understood, particularly on bone health. Our study aimed to assess the prevalence of low bone mineral density (BMD) (Z-score ≤ -2, for vertebral and/or femoral site) in adults with PKU and to investigate associated risk factors, in the French ECOPHEN cohort. The study included 171 patients with 67.3 % of women and a median age of 27 years old. The median femoral and vertebral Z-scores of BMD were both - 0.6. Only 11.4 % of patients had a low BMD. Compared to patients with normal BMD, patients with low BMD had a lower body mass index (BMI) (median 20.4 versus 24.4 kg/m2, p = 0.002), and were more likely to have never stopped their diet (58.8 % versus 31.8 %, p = 0.029). They also had higher total protein intake (1.1 versus 0.9 g/kg/day, p = 0.015), with more proteins from AA supplements (0.80 vs 0.53 g/kg/day, p = 0.010). In multivariate analysis, younger patients born after 1990 and who never stopped diet had a 4.7 times risk to have low BMD (p = 0.005), after adjustment on age, sex, BMI. In summary, our study identified a subgroup of PKU adult patients with low BMD and showed that prolonged low natural protein diet is associated with low BMD
Characterization of coastal habitats and marine benthic communities of the sub-Antarctic Crozet archipelago using underwater imagery
No full textInternational audienceAbstract Sub-Antarctic marine life exhibits unique ecological traits and pronounced endemicity levels. Despite their ecological uniqueness and high conservation value, studies on sub-Antarctic benthic communities are scarce. Using underwater video imagery, we assessed the nearshore diversity and structure of faunal and algal communities of the Crozet archipelago along 12 scuba and remotely operated vehicle transects performed at Baie du Marin and Crique du Sphinx ( Ile de la Possession ). The influence of habitat types on species distribution was evaluated in relation to the setting up of submarine cables. A total of 51 faunal (mainly represented by Echinodermata and Porifera) and 14 algal (mainly represented by Rhodophyta) taxa were identified. The high habitat heterogeneity found in shallow waters (from 0 to 20 m depth) enhances the species richness and diversity, whereas deeper (> 20 m depth) areas were dominated by large sandy stretches and a lower diversity. Rocky habitats had the highest richness and diversity values, promoting local diversity. Submarine cables act as a hard substrate for species, whose suspended sections influence the composition and structure of benthic communities. This study improves our limited knowledge of benthic habitats and diversity from Crozet and constitutes a baseline for further monitoring of marine communities for conservation strategies related to this part of the French Southern Territories National Nature Reserve
Technosols made of urban wastes are suitable habitats for flora and soil macrofauna
No full textInternational audienceCities are increasingly recognized as specific ecosystems, in which green infrastructures, gardens, parks… can offer new habitats to flora and fauna. Cities also have a limited ability to recycle waste, which could be improved by transforming certain construction waste into Technosols. Here, we show that Technosols made of “fine earth”, excavated from deep soil horizons and usually deposited in landfills by the building sector, can promote plant growth, plant diversity and soil macrofauna. A four-year follow-up showed diversity and abundance levels comparable to temperate meadows. It also suggests a strong potential in terms of carbon storage. This solution could thus simultaneously supply a resource for local green spaces, reduce construction waste in landfills, lessen topsoil removal from neighboring environments, helping cities to take their part in climate change mitigation and biodiversity conservation efforts
Autour du sensorium commune. Olfaction, harmonie et système nerveux du XVIe au XIXe siècle
No full textInternational audienceQuel rapport entre les odeurs, la musique et l'exploration scientifique du système nerveux ? Cette intervention explore comment la compréhension scientifique de l'olfaction évolue tout au long des XVIIIe et XIXe siècles, dans les cultures lettrées et savantes, à la faveur de réflexions multisensorielles associant étroitement la perception des odeurs à celle des sons. Ces croyances répandues favorisent des conceptions du corps humain comme un curieux instrument harmonique, notamment grâce à un organe fascinant : le système nerveux