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Molecular gas in a system of two interacting galaxies overlapping on the line-of-sight
No full textGalaxy interactions can disturb gas in galactic discs, compress it, excite it, and enhance star formation. An intriguing system likely consisting of two interacting galaxies overlapping on the line-of-sight was previously studied through ionised gas observations from the integral-field spectrograph Mapping Nearby Galaxies at APO (MaNGA). A decomposition into two components using MaNGA spectra, together with a multi-wavelength study, allowed to characterise the system as a minor-merger with interaction-induced starformation, and maybe AGN activity. We use new interferometric observations of the CO(1-0) gas of this system from the NOrthern Extended Millimeter Array (NOEMA) to confront and combine the spatially-resolved ionised and molecular gas observations. Mock NOEMA and MaNGA data are computed from simulated systems of two discs and compared to the observations. The NOEMA observations of the molecular gas, dynamically colder than the ionised gas, help to precise the configuration of the system, which we revisit as being a major merger. Combination of ionised and molecular gas data allow us to study the star-formation efficiency of the system.</div
Waiting time during admission procedures increases social inequalities in higher education
No full textInternational audienceMany domains in life require people to wait to access better outcomes, such as waiting in line to access prized tickets for a show, waiting to obtain a job offer from a selective firm, or being waitlisted for a prestigious university. Although waiting might be perceived as a fair mechanism to allocate resources, it may have unintended consequences on social inequalities as individuals from lower socioeconomic backgrounds (SES) may be less likely to wait. In this study, we investigate socioeconomic differences in waiting behavior during the higher education admission process in France. To do so, we leveraged a unique national database that recorded the admission behavior of every high schooler in France over a period of three years. During the admissions process, students faced a trade-off: They could either accept an immediate offer from a university or wait in the hope of receiving a preferred offer later. Results collected among 274,316 students reveal that low-SES students were significantly less likely to wait for preferred offers, even when controlling for objective costs and benefits of waiting. This led low-SES students to ultimately enroll in programs they liked less and that were less prestigious. These results highlight how admission procedures generating uncertainty and requiring students to wait may inadvertently exacerbate educational inequalities. Such systems, while efficient, can end up favoring students who wait more. This research contributes to current discussions on admission procedure fairness by illustrating that seemingly neutral algorithms can in fact deepen social inequalities if their design rewards patience
Agnelage d’automne dans le Sud de la France: implications pour l’acquisation et la gestion des ressources au Néolithique
No full textInternational audienceL’organisation des tâches agropastorales et la disponibilité saisonnière des productions animales sont étroitement liées au calendrier de reproduction des troupeaux domestiques. Au Néolithique, les sociétés agropastorales ont dû composer saisonnièrement avec les contraintes environnementales et la physiologie animale. Sous les latitudes tempérées, les brebis alternent annuellement entre une période de fertilité et un repos sexuel, un cycle principalement calé sur la photopériode. Dans le bassin méditerranéen, le cadre climatique, ainsi que l’existence de races ovines méditerranéennes ayant une forte capacité au désaisonnement, ont permis l’émergence de l’agnelage d’automne, contrastant avec le modèle dominant des mises bas printanières en Europe tempérée. Pour reconstuire la saison de naissance des moutons au Néolithique, nous nous appuyons sur l’analyse séquentielle des isotopes stable de l’oxygène (δ18O) dans l’émail dentaire. Des agnelages d’automne ont déjà été observés dès le 6e millénaire avant notre ère dans le sud de la France et en Espagne. Dans le cadre du programme AUTUMN LAMBS, nous élargissons les recherches dans le Sud de la France, tant sur le plan géographique que chronologique afin de mieux comprendre les conditions socio-économiques et paléoenvironnementales ayant conduit à l’émergence et la perduration de ces systèmes d’élevage. Nous présenterons les nouveaux résultats de l’analyse de huit contextes du Sud de la France datés du 6e au 4e millénaires avant notre ère (Montélimar-Daurelle, Grotte Lombard, Les Bréguières, Montou, Mourre de la Barque, Pendimoun, Pertus II, et le Taï), ainsi que de trois contextes d’Europe continentale du 4e millénaires (Arbon Bleiche 3, Chalain 19, Clairvaux XIV). Nos résultats confirment la présence des naissances automnales en Méditerranée dans le Cardial et leur persistance sur la diachronie dans des complexes chronoculturels du VBQ, Chasséen et Ferrières. Ces agnelages d’automne confirment la capacité physiologique des moutons néolithiques au désaisonnement, ainsi que la maîtrise des interactions socio-sexuelles au sein du troupeau par les éleveurs. De plus, ces résultats reflètent un environnement propice, offrant des ressources fourragères suffisantes pour soutenir la lactation en automne, typique du climat méditerranéen. La combinaison d’un agnelage automnal et printanier permettait aux éleveurs de disposer de produits animaux, notamment du lait, sur un temps plus long de l’année, leur offrant ainsi un avantage significatif dans l’acquisition des ressources
Les fouilles d’Henri Delporte à Châtelperron (1951-1962) ou comment un malentendu peut emporter l’éponymie… Quelques réflexions à partir de la révision du stratotype de la « Grotte Effondrée » (Palier sud)
No full textInternational audienceLorsqu’il entreprend de nouvelles fouilles sur le site de la « Grotte des Fées » à Châtelperron (Allier) en 1951, Henri Delporte souhaite contribuer à la « définition de l’industrie de Châtelperron » en répondant à cette question lancinante : « forme-t-elle vraiment le Périgordien I de quelques auteurs ? » (Delporte, 1951). Au rang des interrogations majeures que cette problématique recouvre, se trouve le problème de la filiation culturelle entre le Moustérien et l’industrie de Châtelperron d’une part et entre cette dernière et celle de La Gravette d’autre part. Pour résoudre ces tensions, le préhistorien fait donc le choix de mettre en œuvre une fouille stratigraphique (1951-1954 ; 1962) visant à décrire la séquence de la « Grotte Effondrée » où les fouilles du XIXe siècle ont formellement mis en lumière les vestiges attribués par Henri Breuil à l’Aurignacien inférieur (1906). Les observations qu’il est amené à effectuer sur le terrain lui permettent d’affirmer qu’en dépit du caractère pluristratifié de cette séquence, il n’existe dans l’industrie de Châtelperron aucune coexistence des formes moustériennes et du Paléolithique supérieur attestant le passage des unes vers les autres. Parallèlement, l’étude typologique de l’outillage le conduit à postuler une évolution interne de cette industrie qui ne peut selon lui traduire un phylum avec celle de La Gravette, qui appartient à une phase « nettement individualisée de l’évolution humaine » (Delporte, 1955) et répond à ses propres nécessités évolutives. Ce double constat entraîne Delporte à distinguer « deux cycles de civilisation différents : le Castelperronien et le Gravettien » (Delporte, 1954). Dans le cadre de cette communication, nous tenterons de montrer qu’une mauvaise appréciation des faits archéologiques peut mener, en régime de contradiction, à poser les termes d’une nomenclature chrono-stratigraphique encore en vigueur aujourd’hui. À travers la réévaluation critique des travaux effectués dans les années 1950, nous essayerons de percevoir comment, loin d’être un obstacle, une erreur d’interprétation entendue comme une vérité en sursis peut paradoxalement se trouver au fondement d’un large consensus scientifique. DELPORTE H. (1951) – Formulaire de demande d’autorisation de sondage pour 1951, dossier administratif des fouilles de Châtelperron (1951-1965), Archives du Service régional de l’archéologie d’Auvergne-Rhône-Alpes. DELPORTE H. (1954) – Le Périgordien, Bulletin de la Société préhistorique française, t. 51, p. 44-48. DELPORTE H. (1955) – De la complexité du fait paléolithique à la lumière de fouilles nouvelles (Châtelperron et Germolles), Pallas, III, Annales de la Faculté des Lettres de Toulouse, p. 153-162
Non-Local Correlation Effects in DC and Optical Conductivity of the Hubbard Model
No full textConductivity is one of the most direct probes of electronic systems, yet its theoretical description remains challenging in the presence of strong non-local correlations. In this Letter, we analyze the conductivity of the half-filled single-band Hubbard model and identify the role of spatial correlations across the Mott transition. We show that in the correlated metallic regime, an accurate description of the conductivity requires not only the correct spectral function but also the inclusion of complex multi-electron processes encoded in vertex corrections. The crossover to the Mott insulating regime is marked by a vanishing contribution of vertex corrections to the DC conductivity. However, in the Mott insulating case, vertex corrections remain significant for the optical conductivity
Other spaces’ and dark places: reading heterotopia in Japanese literature and culture
No full textThis special issue of the Japan Forum titled ‘“Other spaces” and dark places: reading heterotopia in Japanese literature and culture’ takes inspiration from Michel Foucault’s theory of ‘heterotopia’ to examine sites that, while closely tied to the temporal and spatial network of Japanese contemporary daily life, also stand apart from the everyday. The spaces we examine vary in nature and across time periods: from the geospatial to the metaphorical, the real to the imagined, the Occupation period to fictional futures. The special issue contains the works of the following scholars: Stephen Dodd, Filippo Cervelli, Thomas Lamarre, Seiji Lippit, Thomas Garcin and Linda Flores. In our explorations of diverse sites such as nightclubs, futuristic societies, university clubs, black markets, convenience stores and narrative space, we demonstrate methods for reading these spaces which are closely intertwined with everyday society but also serve to critique or offer respite from the very society they mirror or represent
Highly selective cannibalism in the Late Pleistocene of Northern Europe reveals Neandertals were targeted prey
No full textInternational audienceThe Troisième caverne of Goyet has yielded the largest assemblage of Neandertal remains in Northern Europe with clear evidence of anthropogenic modifications. However, its skeletal fragmentation has long limited detailed morphological and behavioural study on the assemblage. In this study, we integrate palaeogenetic, isotopic, morphometric, and structural analyses of the long bones to assess the biological profiles of the Neandertals from Goyet and explore whether they present particularities that could shed light on the formation of this unique cannibalised assemblage. We identify a minimum of six individuals, including four adult or adolescent females. Compared to Homo sapiens and Neandertals—including regional specimens—the females from Goyet display short statures and reduced diaphyseal robusticity of their long bones. They lack skeletal markers associated with high mobility despite isotopic evidence for non-local origins. The overrepresentation of short, morphologically gracile, non-local females, alongside two immature individuals, suggests a strong selection bias in the individuals present at the site. Dated between 41,000 and 45,000 years ago, a period marked by Neandertal cultural diversity, biological decline and the arrival of Homo sapiens in Northern Europe, the cannibalised female and juvenile Neandertals from Goyet indicate exocannibalism, possibly linked to inter-group conflict, territoriality, and/or specific treatment of outsiders
Modeling the PAX5P80R Mutation Reveals HIF2α Activation as a Common Feature and Therapeutic Target in B-cell Acute Lymphoblastic Leukemia
No full textInternational audienceAbstract The transcription factor PAX5 is a major target of genetic alterations in human B-cell precursor acute lymphoblastic leukemia (B-ALL). Among the alterations, the P80R mutation affecting the DNA-binding domain represents the most frequent PAX5 point mutation in B-ALL. In contrast to other somatic PAX5 mutations, PAX5P80R defines a distinct B-ALL subtype characterized by a unique transcriptional program. In this study, we aimed to develop a model to elucidate the mechanism by which PAX5P80R perturbs normal B-cell differentiation and the oncogenic relays involved in PAX5P80R-driven malignant progression. A retroviral complementation approach of Pax5-deficient murine fetal liver cells demonstrated at the functional and molecular levels that PAX5P80R failed to rescue definitive B-cell commitment but maintained the repression of T-cell development. Moreover, PAX5P80R eventually led to clonal B-ALL transformation after transplantation through the acquisition of secondary mutations in genes involved in the JAK/STAT and RAS/MAPK pathways. Finally, transcriptomic analyses combined with pharmacologic investigation revealed ectopic activation of HIF2α as a common feature of B-ALL and identified acriflavine as a potent drug against B-ALL. Hence, this study provides a strategy to model the multistep process of B-ALL and sheds light on the biological mechanism by which the PAX5P80R mutation leads to leukemia. Significance: PAX5P80R perturbs normal B-cell development, leads to clonal transformation, and activates HIF2α as an oncogenic relay, providing mechanistic insights that could improve treatment of B-cell acute lymphoblastic leukemia
Genomics of Neotropical biodiversity indicators: Two butterfly radiations with rampant chromosomal rearrangements and hybridization
No full textInternational audienceA central question in evolutionary biology is what drives the diversification of lineages. Rapid, recent radiations are ideal systems for this question because they still show key morphological and ecological adaptations associated with speciation. While most research on recent radiations focuses on those occurring in insular environments, less attention has been given to continental radiations with complex species interactions. Here, we study the drivers of continental radiations of Melinaea and Mechanitis butterflies (Nymphalidae: Ithomiini), which have rapidly radiated in the continental Neotropics. They are classical models for Amazonian biogeography and color pattern mimicry and have been proposed as biodiversity indicators. We generated reference genomes for five species of each genus and whole-genome resequencing data of most species and subspecies covering a wide geographic range to assess phylogeographic relationships, hybridization patterns, and chromosomal rearrangements. Our data help resolve the classification of these taxonomically challenging butterflies and reveal very high diversification rates. We find rampant evidence of historical hybridization and putative hybrid species in both radiations, which may have facilitated their rapid diversification by enriching the genetic diversity. Moreover, we identified dozens of chromosomal fusions and fissions between congeneric species that have likely expedited reproductive isolation. We conclude that interactions between geography, hybridization and chromosomal rearrangements have contributed to these rapid radiations in the highly diverse Neotropical region. We hypothesize that rapid radiations may be spurred if repeated periods of geographic isolation are combined with lineage-specific rapid accumulation of incompatibilities, followed by secondary contact with some gene exchange
Embracing the Modern Biochemistry of Brain Metabolism
No full textInternational audienceThis editorial challenges the long‐held neuron‐centered view of brain metabolism, relying on ample evidence that it is a cooperative, multicellular process. Astrocytes, oligodendrocytes, and other glia play active roles providing lactate, antioxidant support, and substrate shuttles that fuel neuronal function and memory. Despite mounting data, some critics persist in refuting intercellular metabolic exchange, often guided more by entrenched creeds than concrete evidence, slowing constructive, hypothesis‐driven discourse and delaying clinical and neuroprotective advances. The authors call for a rigorous research agenda: cell‐type‐specific manipulations, advanced biosensors, imaging and biomarkers, and integration with behavior and electrophysiology. They urge redirecting focus from outdated dogma to physiology‐driven exploration of glia–neuron metabolic partnerships. imag