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Photobleaching Effects on the Radiation-Induced Attenuation of Germanosilicate Optical Fibers at Low Temperature
No full textInternational audienc
Abelian reduction in differential-algebraic and bimeromorphic geometry
No full textInternational audienceA new tool for the model theory of differentially closed fields and of compact complex manifolds is here developed. In such settings, it is shown that a type internal to the field of constants (resp. to the projective line) admits a maximal image whose binding group is an abelian variety. The properties of such "abelian reductions" are investigated in the Galois-theoretic framework provided by stability theory.Several geometric consequences for the birational geometry of algebraic vector fields of characteristic zero are then deduced. In particular, (1) it is shown that if some cartesian power of an algebraic vector field admits a nontrivial rational first integral then already the second power does, (2) two-dimensional isotrivial algebraic vector fields are classified up to birational equivalence, and (3) algebraic vector fields whose finite covers admit no nontrivial factors are studied in arbitrary dimension.Analogues of these results in bimeromorphic geometry are also obtained
Repudiato patrum stemmate. The Topos of origins in the early Latin Lives of saints
No full textInternational audienc
Sharp propagation of chaos for McKean-Vlasov equation with non constant diffusion coefficient
No full textInternational audienceWe present a method to obtain sharp local propagation of chaos results for a system of N particles with a diffusion coefficient that it not constant and may depend of the empirical measure. This extends the recent works of Lacker [14] and Wang [24] to the case of non constant diffusions. The proof relies on the BBGKY hierarchy to obtain a system of differential inequalities on the relative entropy of k particles, involving the fisher information
Gene expression shifts in emperor penguin adaptation to the extreme antarctic environment
No full textSpecial Issue: ECOLOGY OF GENE EXPRESSIONInternational audienceGene expression can accelerate ecological divergence by rapidly tweaking the response of an organism to novel environments, with more divergent environments exerting stronger selection and supposedly, requiring faster adaptive responses. Organisms adapted to extreme environments provide ideal systems to test this hypothesis, particularly when compared to related species with milder ecological niches. The Emperor penguin (Aptenodytes forsteri) is the only endothermic vertebrate breeding in the harsh Antarctic winter, in stark contrast with the less cold-adapted sister species, the King penguin (A. patagonicus). Assembling the first de novo transcriptomes and analysing multi-tissue (brain, kidney, liver, muscle, skin) RNA-Seq data from natural populations of both species, we quantified the shifts in tissue-enhanced genes, co-expression gene networks, and differentially expressed genes characterising Emperor penguin adaptation to the extreme Antarctic. Our analyses revealed the crucial role played by muscle and liver in temperature homeostasis, fasting, and whole-body energy metabolism (glucose/insulin regulation, lipid metabolism, fatty acid beta-oxidation, and blood coagulation). Repatterning at the regulatory level appears as more important in the brain of the Emperor penguin, showing the lowest signature of differential gene expression, but the largest co-expression gene network shift. Nevertheless, over-expressed genes related to mTOR signalling in the brain and the liver support their central
Candidatures aux élections et cause des immigrés
No full textInternational audienceDepuis les années 1968, les militants de la cause immigrée intègrent dans leurs revendications l’accès égal aux droits civiques, dont le droit de vote et d’éligibilité réclamé par diverses actions comme celle que rappelle la notice biographique de Paul Oriol dans cette rubrique. Ces militants s’investissent dans le champ des élections en menant des campagnes incitant les enfants français d’immigrés à s’inscrire sur les listes électorales ou encore en tentant de faire intégrer dans les programmes des partis politiques des revendications propres à cette cause – depuis l’intérieur à travers des « commissions immigration » comme au sein du Parti socialiste (PS) ou du Parti socialiste unifié (PSU), ou depuis l’extérieur en saisissant l’opportunité des campagnes pour négocier avec ces partis. Enfin, certains militants étrangers exclus de la citoyenneté intègrent les élections à leur registre d’action en votant ou en se présentant de façon symbolique avec un programme défendant les immigrés, comme Djellali Kamal en 1974 et Saïd Bouamama en 1989. D’autres, Français issus de l’immigration, ont mis en place des listes indépendantes des partis ou ont été investis comme « candidats d’ouverture » – comme Djida Tazdaït et Léla Bencharif en 1989 – pour le compte d’organisations constitutives de la cause des immigrés avec pour mission de porter les revendications de cette dernière
Fluorescent nanoparticles for security tags against the looting of archaeological artefacts
No full textInternational audienceSeveral security solutions exist to reduce the risk of looting and theft of cultural artefacts, including systematic tagging to deter illicit trade. This study explores the integration of fluorescent nanoparticles with unique optical properties into ready-to-use conservation varnishes for archaeologists. Various nanomaterials (carbon dots, chalcogenides, and perovskite quantum dots) were incorporated into conservation resins to develop diverse tagging solutions compatible with archaeological artefacts. Their stability was assessed through accelerated aging by comparing their initial fluorescence brightness and its reduction after aging. Paraloid-based tags provided superior protection to alternative resins, while perovskite quantum dots exhibited instability under harsh conditions compared to other nanomaterials. Potential interferences with composition analysis were also evaluated by determining which tags could be detected using ED-XRF and WD-XRF. This study complements existing security tagging methods and may contribute to the broader adoption and improvement of traceable tagging solutions
Apprendre à respecter les limites planétaires
No full textFestival des initiatives locales et positivesConférence publique donnée dans le cadre du « Festival des initiatives locales et positives » 2025 organisé par l'association "Groseille et ciboulette"
