226280 research outputs found
Sort by
Renormalization of the Quantum Stress Tensor Fluctuations and the Limits of Semiclassical Gravity
No full textInternational audienceWe analyze the expectation value of the energy-momentum tensor and its fluctuations in quantum field theory on curved spacetimes . A necessary condition for the conceptual consistency of semiclassical gravity, where represent the sources of the Einstein equations, is that the fluctuations of the energy momentum tensor remain small compared to its expectation value. We study the renormalization of both the energy-momentum tensor and the fluctuation tensor for suitable Hadamard states, using the operator product expansion for a free scalar field on a fixed curved background. We show that squeezed vacua -- arising naturally in black hole evaporation and in inflationary cosmology -- fail to satisfy the semiclassicality criterion
Pseudopaline-mediated zinc uptake by Pseudomonas aeruginosa drives clinically relevant phenotypes and infection outcomes
No full textInternational audienceBiological metals are vital trace elements required by metalloproteins, which are involved in virtually every cellular, structural, and catalytic function of the bacterial cell. Bacterial pathogenesis involves a tug-of-war between the host's nutritional immunity sequestering essential metals and the invading pathogens that deploy adapted high-metal affinity uptake strategies, such as metallophores, in order to efficiently circumvent these defense mechanisms. Pseudopaline is a metallophore produced and secreted by Pseudomonas aeruginosa to acquire zinc when the bioavail ability of this metal is severely restricted, as in the presence of a strong metal che lator such as EDTA, or during infections when the nutritional immunity of the host is active. We show that when facing strong metal chelation, the general Znu zinc uptake pathway becomes ineffective and only the pseudopaline pathway is capable of supplying the bacteria with the necessary zinc to maintain their growth, establishing that the pseudopaline pathway is the last-resort pathway for the bacteria to acquire zinc under such restricted growth conditions. Based on this statement, the present study explores the pleiotropic role of pseudopaline-mediated zinc acquisition on clinically relevant phenotypes such as biofilm formation and associated antibiotic tolerance, as well as its capacity to determine infection outcomes using cell-culture and murine models. The expression of pseudopaline-dependent phenotypes in such a diversity of biological contexts demonstrates the essentiality of this specific metal uptake system for P. aeruginosa pathogenicity during infection. We therefore identify this machinery as a promising therapeutic target for P. aeruginosa infections
Questionnaires d’enquête : extrait du projet RADHY-Buëch
No full textCe document est en lien avec la démarche géoprospective du projet RADHY Buëch exposée dans l'article :"La géoprospective comme aide à la réflexion sur les futurs possibles de l’eau et de sa gestion : exemple d’une recherche en cours dans le bassin-versant du Buëch", Revue GéocarrefourThis document presents two questionnaires from a survey conducted as part of the geoprospective component of the RADHY-Buëch research project. The survey aims to elicit the perspectives of local stakeholders on the possible futures of water and its management in the Buëch region. These perspectives will then be used to develop scenarios for potential futures and local adaptations. To this end, an online survey combined with interviews was conducted in June and July 2020.Questionnaire 1 – The Buëch Today – focuses on the perception of the Buëch basin and the current water system within this region.Questionnaire 2 – The Buëch in the Future – focuses on the vision of the perceived and desired future of the Buëch region and its water system in light of ongoing environmental and societal changes.Le document présente les deux questionnaires d'une enquête réalisée dans le cadre du volet géoprospectif du projet de recherche RADHY-Buëch. L'enquête a pour objectif de faire émerger les visions qu’ont les acteurs du territoire des futurs possibles de l’eau et de sa gestion dans le Buëch, à partir desquelles seront construits des scénarios des futurs possibles et des adaptations locales. Pour ce faire, une enquête en ligne couplée à un entretien a été menée en juin et juillet 2020.Le questionnaire 1 - Le Buëch aujourd’hui - porte sur la perception du bassin du Buëch et du système eau actuel au sein de ce territoire.Le questionnaire 2 - le Buëch dans le futur - porte sur la vision du futur perçu et souhaité du territoire du Buëch et du système eau face au changements environnementaux et sociétaux en cours
Holocene climatic changes in the Kerguelen archipelago (South Indian Ocean) based on marine and lacustrine palaeoclimatic archives
No full textInternational audienceClimatic variability in the Southern Hemisphere is largely controlled by the latitudinal position of the Southern Hemisphere Westerly Winds (SHW), whose migration influences precipitation, temperature, and Antarctic upwelling. This study presents the results of analyses of two lacustrine sediment cores from Lake Armor, located on the subantarctic Kerguelen Islands (49 • 15′S, 69 • 10′E), within the SHW belt. Lipid biomarkers (Glycerol Dialkyl Glycerol Tetraethers, n-alkanes, and their hydrogen isotopes) were used to reconstruct mean annual air temperature above freezing (MAF) and humidity conditions. These records are compared with a high-resolution diatom-based summer sea surface temperature (SST) reconstruction from marine core MD11-3353, situated 150 km southwest of Lake Armor. In the late glacial and Early Holocene, our results reveal a period of warm air temperature, comparable to current values and very warm sea surface temperature, 5°C above the current values. Around 9000 cal a BP, an abrupt transition occurred, marked by a cooling of 5°C in SST and 1.5°C in MAF, interpreted as a northward migration of the SHW and associated oceanic fronts. The Mid-to-Late Holocene period is characterized by pronounced MAF variability, including a notably warm interval between 3000 and 2000 cal a BP, when n-alkane dD suggests the prevalence of wetter conditions. Since ~250 cal a BP, a southward migration of the SHW has produced a 2.5°C rise in MAF. Our findings are overall consistent with previous studies from the Indian Ocean, but permit us to go a step further as by comparing SSTs and air temperatures. This suggests that SST is not a reliable predictor of air temperature on the Kerguelen Islands, particularly during the Early Holocene. We hence argue that Kerguelen air temperature is predominantly controlled by the position of westerly winds, as an indicator of reorganisations in air mass trajectories
Genomics of Long-Term Complications of Childhood Leukemia: Rationale and Design of the GenLEA Study
No full textCited by: 0International audienceBackground: Survivors of childhood acute leukemia are at risk of long-term treatment-related complications, but the role of genetic susceptibility remains unclear. We describe here the GenLEA project, which was established to investigate genetic determinants of long-term complications. Methods: GenLEA builds on the French LEA cohort, which prospectively follows acute leukemia survivors since 2004 through standardized dedicated consultations every 2 to 4 years. Patients were selected from the nested CryoLEA biobank. Cases were defined as survivors with at least one of four major complications (anthracycline-related cardiomyopathy, secondary malignant neoplasms, metabolic syndrome, or osteonecrosis) while controls were survivors without these complications, selected with the objective of a 1:3 case-to-control ratio. Genetic data were generated using genome-wide genotyping and whole-exome sequencing. Results: After quality control, 743 patients were included for analyses (241 cases and 502 controls). Fifty-one percent were male with a median age at diagnosis of 7.3 years (IQR 3.9–13.0), and median follow-up reached 14 years (IQR 7.9–19.8). Among the cases, 44 had cardiomyopathy, 50 osteonecrosis, 37 secondary malignant neoplasms, and 163 metabolic syndrome. Planned analyses include genome-wide association studies (GWAS) and downstream analyses such as transcriptome-wide association studies (TWAS) and Mendelian randomization on genotyping data, as well as gene-based tests on exome sequencing data. Perspectives: By integrating these approaches with high-quality clinical information, GenLEA offers a unique opportunity to identify molecular determinants of late complications after childhood acute leukemia. This collaborative resource will support replication efforts, meta-analyses, and ultimately the development of personalized long-term follow-up strategies. © 2026 Wiley Periodicals LLC
Renforcer les perspectives critiques : un appel à l'ouverture en management des systèmes d'information
No full textInternational audienceThis editorial is a call to the IS community to mobilize critical perspectives. To this end, thiseditorial presents the theoretical and conceptual origins of critical perspectives as well as their evolution in IS. Drawing on recent and diverse articles in the literature, the authors argue for the relevance of critical perspectives in illuminating current issues in ISCet éditorial est un appel à la communauté MSI pour mobiliser ces perspectives. Il présente les origines théoriques et conceptuelles des perspectives critiques ainsi que leur évolution en MSI. En s'appuyant sur des articles récents et variés dans la littérature, les autrices argumentent de la pertinence des perspectives critiques pour éclairer des enjeux actuels en MSI.</div
Another World Is Possible—It Is Already Here: A Review and Research Agenda on Alternative Organizing
No full textInternational audienceAmid multiple crises on a planetary scale, alternative organizing offers plural possibilities for reconfiguring societal relations and bringing into being a more livable world. Despite growing interest, the literature on alternative organizing remains fragmented, marked by a narrow and selective integration of disciplinary and geographic knowledge communities. This fragmentation leads to ambiguities and contradictions in concepts and theory development. To address these issues, we review 50 years of research on alternative organizing, following three steps. First, we map the genealogy of research on alternative organizing, identify its relations with institutional orders, and distinguish key perspectives. Second, we develop an integrative framework that (a) identifies three constitutive dimensions of alternative organizing—imaginaries, alterity, and subjectivities—and (b) synthesizes the processes, frictions, and outcomes for societal transformation. Drawing on this framework, we suggest avenues to attune to the ways alternative organizing unsettles dominant orders and cultivates the present and future, other-wise
How Particle Size Affects Consolidation Behavior, Strain and Properties of Li 6 PS 5 Cl Fast Ionic Conductors
No full textInternational audienceSolid‐state battery fabrication requires the densification of solid electrolytes to achieve optimal cycling performance and high energy density. However, the underlying compaction mechanisms of these electrolytes remain poorly understood. Here, we investigate the effect of pressure consolidation on the ionic conductor Li 6 PS 5 Cl with particle size distributions (PSD) ranging from 4 to 40 µm. Heckel analysis reveals that samples with smaller PSDs exhibit higher compressibility at lower pressures. X‐ray diffraction peak profiling shows that applied pressure induces lattice strain, leading to peak broadening, while pair distribution function analysis demonstrates a reduction in coherence length upon pressing. Dark‐field X‐ray microscopy further provides spatially resolved orientation maps, uncovering intragranular structural variations within individual Li 6 PS 5 Cl agglomerates after compression. To better understand the origin of stress fluctuations, we performed discrete element method simulations using the experimental PSDs. The results indicate that smaller particles and broader PSDs experience higher stresses, whereas monodisperse systems do not exhibit significant stress fluctuations with position or particle size. This suggests that the high strain observed cannot be attributed solely to smaller particles, but rather to size inhomogeneity. Overall, these findings highlight that both particle size and its distribution play a critical role in processing solid electrolytes for solid‐state batteries
Divorce in time of war and displacement, between social anxiety and changing family practices: the case of northwest region of Syria in 2022
No full textInternational audienceThis paper expands the research on familial change in the context of war and displacement in Syria. It examines the multiple factors contributing to an actual or perceived increase in divorce rates among Syrian couples, and why it has become such a widely debated topic of concern in a society where divorce is still considered taboo. This paper looks more closely at the case of the northwestern region of Syria that welcomed almost 2.87 million internally displaced persons in 2022. Moving beyond analyses that focus primarily on economic explanations for familial change, we argue that divorce should be understood as the result of interlocking social, economic and political factors. First, we argue that displacement created new marital norms and practices, as a result of the dissolution of kinship networks. Secondly, displacement led to the loss of livelihoods and worsened living conditions, resulting in a consequent reorganisation of roles among family members, and potential tensions. Third, the unclear jurisprudence that characterises the region conveys a sense of instability and lack of family-law regulation, which complicates family reunification and the application of court decisions in divorce proceedings
