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Streaming over Micro-Perforated walls submitted to acoustic plane wave
No full textInternational audienceMicro-perforated panels (MPPs), lightweight structures, are investigated as alternatives to huge or active devices,to attenuate noise induced by external flow into the passenger compartment of automobile or aircraft cabins. Optimal sound absorption performance is achieved by appropriate selection of MPP geometry. The viscous lossesthrough the apertures dissipate the acoustic energy around the Helmholtz resonance and provide high absorption efficiency over a wide bandwidth. Acoustically induced vorticity, due to streaming at the hole inlet/outlet, could alsocontribute. The experiment quantifies the flow induced by acoustic pressure fluctuations (”streaming”) in the vicinityof the perforations of an MPP placed on a cavity arranged on the wall of a closed tube. Three diameters ofperforations (1mm, 0.6mm and 0.3mm) are tested. The flow induced by an acoustic plane wave parallel to thesurface of the MPP is characterized by TR-PIV (”Time Resolved Particle Image Velocimetry”), a laser optical diagnostics, synchronized with acoustic measurements by microphone. The dynamics of the jets emitted at the holesaccording to their relative position to the wavelength associated with different identified eigenmodes of the closedtube is highlighted. The objective is to estimate the viscous dissipation associated with these micro-jets and tolink it to acoustic absorption
Transidentité et sport de haut niveau: Étude juridique sur l’éligibilité des personnes transgenres dans les compétitions sportives
No full textHigh-intensity interval and moderate-intensity continuous training on cerebral energy metabolism in older rats
No full textInternational audienceAging is associated with metabolic decline in the brain, increasing susceptibility to neurodegenerative diseases. While exercise is a well-established strategy to counteract these changes, no study has directly compared the effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on cortical and hippocampal energy metabolism—key regulators of brain plasticity in aging. To address this gap, we investigated how 4-week MICT and HIIT protocols, structured according to the lactate threshold, affect endurance performance and brain metabolic markers in older Wistar rats. Both training modalities improved endurance, with HIIT demonstrating superior gains in maximal performance. However, molecular analyses revealed that MICT induced more extensive metabolic and angiogenic adaptations in the cortex and hippocampus, including the upregulation of key regulators of energy metabolism and vascularization. RNA sequencing confirmed broader transcriptomic changes following MICT, implicating pathways associated with neurogenesis, metabolic homeostasis, and cellular plasticity. While HIIT provided a time-efficient means of improving cardiovascular endurance and mitochondrial activity through different molecular pathways when compared to MICT, its impact on brain metabolism was more limited. These findings suggest that MICT is the preferred regimen for enhancing cerebral metabolic function and neurovascular adaptation, while HIIT serves as a complementary strategy to involve other brain metabolism-associated pathways and maximize aerobic fitness. A direct comparison of these modalities, as presented here, is essential for refining exercise prescriptions to support brain health in aging
Rencontre autour de la mémoire : pré-actes
No full textInternational audienceLa plupart des sociétés humaines, passées comme actuelles, ont répondu et répondent au décès de leurs membres par la mise en oeuvre, le plus souvent à court terme, de rites de séparation destinés à marquer l’intégration du défunt au monde des morts. Cette séparation, aux dimensions tant symboliques (passage vers l’au-delà) que physiques (mise à distance, voire destruction du cadavre), ne signe cependant que rarement la disparition du lien unissant les vivants à leurs morts, les premiers conservant le souvenir des seconds et pouvant, dans bien des cas, en entretenir la mémoire bien après le temps des funérailles. Cette mémoire, qui s’exprime à différentes échelles – celle de l’individu, de la famille, du groupe –, peut prendre des formes multiples et s’appuyer sur une grande variété de supports. Immatérielle par essence, elle peut parfois s’ancrer matériellement dans un lieu ou un objet. Dépendante des vivants qui la perpétuent, elle s’avère bien souvent mouvante au fil des ans et contrainte en termes de temporalité. Elle peut, en outre, ne pas viser au seul souvenir du défunt et refléter des contextes et enjeux sociétaux lui donnant cadre, sa mise en oeuvre confinant par exemple dans certaines sociétés à la recherche d’une sorte de transcendance de la mort, servant dans d’autres des desseins idéologiques ou politiques.Riche d’enseignements sur les sociétés passées et actuelles, la question de la mémoire des défunts et de son négatif, l’oubli, sera au coeur de la 16e Rencontre du Gaaf. À vocation internationale et pluridisciplinaire, ce colloque se veut être un lieu d’échanges entre chercheurs issus d’horizons divers, invitant les contributions d’archéologues et anthropologues travaillant sur des contextes chrono-géographiques variés, ainsi que d’acteurs d’autres disciplines des sciences sociales (p. ex. historiens, sociologues, ethnologues). Les discussions scientifiques s’articuleront autour de quatre grandes thématiques. Deux d’entre elles aborderont respectivement la question de la matérialité et de la temporalité de la mémoire, en s’intéressant à ses supports physiques (monuments, épitaphes, sources textuelles et iconographie, etc.) et aux différents temps funéraires (lesquels diffèrent selon que l’on aborde la question du côté biologique, du côté social ou du côté idéel). Un troisième thème s’attachera à discuter les ressorts et motivations de la construction, voire de la reconstruction, de la mémoire. Enfin, un dernier thème abordera la problématique selon un angle de vue antagonique, en considérant la dépréciation, la privation ou la négation de cette mémoire, et l’invisibilisation de certains morts ou de certains groupes qui en résulte dans différents contextes
Preparing for the Next Generation of Material Environmental Health and Safety (EHS) Concerns: Guidelines for Future Data Curation Collaborations
No full textInternational audienceEmergence of a new class of nanoscaled contaminants, such as micro-and nanoplastics, as well as nanotechnology's current transition into advanced materials have broadened the boundaries of the field. These field-expanding topics exemplify the core role of collaboration in creating "good" and trustable data for future analyses. It is imperative that the environmental health and safety community recalls previous efforts to integrate data surrounding engineered nanomaterials to serve as guidance for the next generation of materials. We therefore describe an international collaboration focused at the early stages in the informatics process, the data curation level. Our experiences are described in nine guidelines that can be adopted by future collaborations. These guidelines were written to be actionable and structured within scalable phases. Guidance is also provided on the necessary personnel roles that should be incorporated into funding plans for developing and using advanced materials. Current shifts in the field demand community consensus to define data that are qualified as "good" and "trustable", which require collaboration at the early stages of the informatics and data generation processes
Ranking Methods for Skyline Queries
No full text{Multi-criteria decision analysis in databases has been actively studied, especially through the Skyline operator. Yet, few approaches offer a relevant comparison of Pareto optimal, or Skyline, points for high cardinality result sets. We propose to improve the dp-idp method, inspired by tf-idf, a recent approach computing a score for each Skyline point, by introducing the concept of dominance hierarchy. As dp-idp lacks efficiency and does not ensure a distinctive rank, we introduce the RankSky method, the adaptation of Google’s well-known PageRank solution, using a square stochastic matrix, a teleportation matrix, a damping factor, and then a row score eigenvector and the IPL algorithm. For the same reasons as RankSky, and also to offer directly embeddable in DBMS solution, we establish the TOPSIS based CoSky method, derived from both information research and multi-criteria analysis. CoSky automatically ponderates normalized attributes using the Gini index, then computes a score using Salton's cosine toward an ideal point. By coupling multilevel Skyline to dp-idp, RankSky or CoSky, we introduce DeepSky. Implementations of dp-idp, RankSky and CoSky are evaluated experimentally
Analyse et identification de Plans de Gestion de Données disciplinaires pouvant être utilisés comme exemple: Produit du Groupe de Travail PGD Disciplinaires de RDA France
No full textRDA France, le chapitre français de la Research Data Alliance (RDA), a mis en place en mars 2023 le groupe de travail RDA France – Plans de Gestion de Données disciplinaires (GT PGD-DISC), avec l’objectif de constituer un corpus de plans de gestion des données (PGD) disciplinaires pouvant être utilisés comme exemple. Ce document décrit en introduction les raisons pour lesquelles RDA France a créé ce groupe de travail et la manière dont le groupe a été constitué (Section 1), puis la méthodologie employée pour élaborer le corpus (Section 2) et le contenu de celui-ci, en termes de données et de métadonnées (Section 3). La maintenance envisagée pour le corpus est décrite en conclusion (Section 4).La Version 1 de la liste de plans de gestion de données disciplinaires résultant du travail du groupe est publiée dans l’entrepôt de l’infrastructure Recherche Data Gouv (https://doi.org/10.57745/ZSWLYJ)
ANR Ecomed, An 1 : retour sur la première année du programme (2024-2025)
No full textECOMED (https://ecomed.hypotheses.org/600
Microbial Ecology of Permafrost Soils: Populations, Processes, and Perspectives
No full textInternational audiencePermafrost microbial research has flourished in the past decades, due in part to improvements in sampling and molecular techniques, but also the increased focus on the permafrost greenhouse gas feedback to climate change and other ecological processes in high latitude and alpine permafrost soils. Permafrost microorganisms are adapted to these extreme environments and remain active at low temperatures and when resources are limited. They are also an important component of global elemental cycles as they regulate organic matter turnover and greenhouse gas production, particularly as permafrost thaws. Here we review the permafrost microbiology literature coupled with an exploration of its historical aspects, with a particular focus on a new understanding advanced by molecular biology techniques. We further identify knowledge gaps and ways forward to improve our understanding of microbial contributions to ecosystem biogeochemistry of permafrost‐affected systems