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Not enough H<sub>2</sub>O<sub>2</sub> to warm early Mars
No full textInternational audienceThere exists strong geomorphological, sedimentary and mineralogical evidence that Mars had an active surface hydrological cycle during the Noachian period, about 3.8 Gyr ago (Ga). However, how surface temperatures compatible with perennial liquid water could be sustained in spite of a Sun that only had 75% of its present-day brightness has remained elusive, leading to the faint young Sun paradox for Mars. Recently, the greenhouse effect of hydrogen peroxide (H2O2) has been proposed as a solution by Ito et al. (2020). Radiative transfer models have shown that a few ppmv of H2O2 in a 1 or 2 bar CO2 atmosphere could solve the faint young Sun paradox on early Mars. In a warm and wet CO2 atmosphere, H2O2 is produced by photochemistry and contributes to the stability of the CO2 atmosphere along with the HOx (H, OH and HO2) catalytic cycles. Nevertheless, a thorough assessment of the viability of such a high H2O2 abundance is still lacking. Using 1D and 3D climate models coupled with a C–H–O photochemistry solver, we show that in the most favorable case for H2O2 to build up, its steady-state abundance is several orders of magnitude short from its required abundance of ∼ 1 ppmv to have a significant radiative effect. Furthermore, we also show that a transient warming episode associated with massive H2O2 release cannot exceed 10 Martian years. We therefore rule out H2O2 as a warming agent for early Mars
Déploiement des renouvelables en Afrique : entre injustice et leviers juridiques pour une transition juste
No full textNational audienceAlors qu’on fête l’anniversaire de 10 ans de l’Accord de Paris sur le changement climatique, certains concepts posés par ce texte présentent encore de contours peu définis et soulèvent plus d’interrogations qu’ils n’apportent de réponses. La justice climatique demeure ainsi une notion mouvante de par les effets du changement climatique lui-même. Nos configurations sociales et politiques en font un concept en constante transformation y compris juridique. Cette journée internationale se pose comme un moment de réflexion systémique et comparée autour de la Justice climatique et de la Transition Juste. L’espace étudié est ouvert aux problématiques climatiques et aux vulnérabilités d’autres continents, notamment le Sud Global. Les temporalités accordent une place aux générations futures. Issue d’un projet de recherche transformateur, la démarche est innovante et pionnière car elle est portée par la jeune recherche. À partir d’un nouveau format dénommé « incubateur », la journée d’étude vise à échanger et débattre sur ces thèmes croisés
Evaluating the applicability of ESGO quality indicators in the surgical management of endometrial cancer: Insights from a Francogyn cohort
No full textInternational audienceBackground: Endometrial cancer (EC) is a significant health concern in France, necessitating high-quality surgical care to improve patient outcomes. The European Society of Gynaecological Oncology (ESGO) established quality indicators (QIs) to standardize and improve management.Objective: This study evaluates the applicability of ESGO QIs in a real-world setting across 13 centers in France.Methods: This retrospective multicenter cohort study included 2789 patients surgically treated for EC from 2001 to 2020. Demographic data, surgical techniques, adherence to ESGO QIs and trends over time were analyzed. Key indicators analyzed included multidisciplinary team discussions, pre-operative imaging adequacy, surgical techniques employed, and molecular classifications.Results: All patients were discussed in multidisciplinary meetings. Adequate preoperative imaging was achieved in 80.63 % of cases. Minimally invasive surgery was performed in 66.12 % of early-stage patients, showing a significant year-on-year increase from 12 % in 2001 to 85 % in 2020. Among obese patients, 60.78 % underwent laparoscopic procedures, with a conversion rate to open surgery of 3.57 %. Molecular classification results highlighted 35 % of patients as low risk and 32 % as high risk.Conclusion: Our findings indicate that adherence to actual ESGO QIs has substantially improved the quality of surgical management for endometrial cancer in France, despite some areas requiring further enhancement. A coordinated political approach is essential to address existing barriers and ensure consistent implementation of these quality standards across all centers, ultimately aiming to elevate patient care and outcomes in the French healthcare system
Involvement of Taiman in juvenile hormone signaling controlling sexual maturation in a male moth
No full textInternational audienceIn insects, juvenile hormone (JH) is essential for orchestrating reproductive events. For example, in the male moth Agrotis ipsilon, the behavioral response to female sex pheromone is linked to neuronal sensitivity in the primary olfactory centers (antennal lobes, ALs), and the maturation of accessory sex glands (ASGs) are known to be age-and JH-dependent. The molecular basis of this regulatory action of JH is not fully deciphered, and we show here that the heterodimerizing partner of Methoprene-tolerant called Taiman (Tai) is essential for the sexual maturation of male A. ipsilon. Tai expression in ALs and ASGs is elevated from the third day of adult life and is responsible for the acquisition of behavioral responsiveness to the sex pheromone and ASG maturation. Tai-deficient old males exhibited altered sexual behavior and delayed ASG maturation. Moreover, the expression levels of Tai and Krüppel homolog 1 (Kr-h1), an early JH-induced transcription factor, were reduced in ALs and ASGs of JH-deprived and Tai-deficient old males, respectively. Exogenous JH injection into young males resulted in precocious sexual maturation and this JH induction was suppressed by Tai silencing. Our results demonstrate that Tai is an actor of the JH signaling pathway that operates in ALs and ASGs to promote pheromone information processing and consequently the display of sexual behavior in synchrony with ASG maturation, ultimately optimizing male reproductive success. Thus, this study provides additional insights into the molecular mechanisms underlying hormonal regulation of sexual maturation in insects
The BIOMASP+ project on biosphere-atmosphere exchanges and their role in air pollution in the subtropical megacity of São Paulo: motivations, methods and preliminary observations
No full textInternational audienceAir pollution, especially in urban areas, is the result of a complex mixture of natural and anthropogenic emissions and their atmospheric processing. It causes millions of premature deaths worldwide and affects plant metabolism, which in turn alters the emissions of Biogenic Volatile Organic Compound (BVOCs) by plants. By taking the subtropical Metropolitan Area of São Paulo (MASP) as a natural laboratory, the BIOMASP+ project (BIOsphere-atmosphere interactions in the Metropolitan Area of São Paulo - plus) a ims to evaluate the interplay between the biosphere and secondary pollution (ozone and SOA formation and aging). The Brazilian Atlantic Forest (Mata Atlântica) is the target ecosystem as the fifth biodiversity hotspot in the world. Here we present the scientific motivations of the project, its methodology and the preliminary observations from the Special Observation Periods of year 2023 (SOP1, 2, 3 and 4). BIOMASP+ is (i) integrative, by combining in-situ/remote/laboratory observations andmodeling, (ii) multidisciplinary, addressing micrometeorology, urban climate, atmospheric chemistry and biology. The project involves multiple nested scales: from leaf to above-canopy levels, from very short time (microseconds) to multi-year scale, from few millimeters (turbulence scale) to synoptic scale. In particular, the experimental effort relies on the implementation of two contrasting supersites (primary forest and urban forest) with a 30-m and 20-m flux towers, respectively, and a variety of state-of-the-art instruments. Ambient observations and the quantification of BVOC emissions have highlighted the complex interactions between meteorology, atmospheric composition of pollution, biogenic emissions of representative remnants of the Atlantic Forest and anthropogenic emissions
Econometrics at the Extreme: From Quantile Regression to QFAVAR 1
No full textThis paper surveys quantile modelling from its theoretical origins to current advances. We organize the literature and present core econometric formulations and estimation methods for: (i) cross-sectional quantile regression; (ii) quantile time-series models and their time-series properties; (iii) quantile vector autoregressions for multivariate data; (iv) quantile panel models for longitudinal data; and (v) quantile factor-augmented models for information compression in data-rich environments. Each section outlines theoretical foundations and developments, followed by representative empirical applications. Finally, the survey highlights open gaps in quantile modelling. By studying distributional dynamics beyond averages, quantile methods provide policymakers and regulators with tools to design interventions that are robust to risks and effective across the entire spectrum of possible outcomes
Mid- and Far-Infrared Spectral Signatures of Mineral Dust from Low- to High-Latitude Regions: significance and implications
No full textInternational audienceMineral dust absorbs and scatters solar and infrared radiation, thereby affecting the radiance spectrum at the surface and top-of-atmosphere and the atmospheric heating rate. While half of the outgoing thermal radiation is emitted in the far infrared (FIR, 15–100 μm), knowledge of the optical properties and thermal radiative effects of dust is currently limited to the mid-infrared region (MIR, 3–15 μm). In this study we performed pellet spectroscopy measurements to evaluate the MIR and FIR contribution to dust absorbance and explore the variability and spectral diversity of the dust signature within the 2.5–25 μm range. Thirteen dust samples re-suspended from parent soils with contrasting mineralogy were investigated, including low and mid latitude dust (LMLD) sources in Africa, America, Asia, and Middle East, and high latitude dust (HLD) from Iceland. Results show that the absorbance of dust in the FIR up to 25 μm is comparable in intensity to that in the MIR. Also, spectrally different absorption (position and shape of the peaks) is observed for HLD compared to LMLD, due to differences in mineralogical composition. Corroborated with the few available literature data on absorption properties of natural dust and single minerals up to 100 μm wavelength, these data suggest the relevance of MIR and FIR interactions to the dust radiative effect for low to high latitude sources. Furthermore, the dust spectral signatures in the MIR and FIR could potentially be used to characterise the mineralogy and differentiate the origin of airborne particles based on infrared remote sensing observations
Matriarchy, Gender and Power: Interdisciplinary perspectives
No full textInternational audienceThis book explores the conceptualizations of female power through the notion of matriarchy in a variety of historical, cultural and epistemological contexts.Matriarchy has been both marginalized, and even derided, as an object of study albeit consistently referred to as a symbol of female power. The lack of serious engagement with matriarchy has stifled critical inquiry into alternative ways of organizing gendered power, and this gap is that this book seeks to address. Re-examining matriarchy from a scientific and interdisciplinary perspective, this book aims to move beyond the simplistic binaries of male vs. female power through diverse enquiries into the concept of matriarchy that conceptualizes power not as domination, but as interconnection, nurturing, and community-oriented leadership. Through this approach, the contributions examine the emancipatory possibilities of matriarchy, while also acknowledging the limitations and challenges that come with it.An interdisciplinary approach having international scope, this work will appeal to postgraduate students and academic researchers of Sociology, Anthropology, History, Art History, Asian Studies, American Studies, African American and Africana Studies, Women’s Studies, Gender Studies, and Law
Cadres et dirigeants d'établissement scolaire : comprendre et réguler la relation au temps et au travail
No full textInternational audienceCette communication s'inscrit ans le cadre du Colloque "La direction dans tous ses états" qui s'est déroulé à l'Université Catholique de l'Ouest à Angers et qui porte sur un travail pluriannuel de recherche réalisé par un collectif de chercheurs - Paola Duperray Laurence Durat, Simon Mallard, Gwenola Reto, Rozenn Decret-Rouillard, Bernard Mercier et Bruno Grave). Les auteurs de cette communication (Paola Duperray, Rozenn Decret-Rouillard et Gwenola Reto) ont présenté un premier état de leurs résultats. Claire Ravez a réagi en proposant une synthèse de ses observations et commentaires.La gestion du temps constitue un enjeu central pour les directions scolaires. Pour ces professionnels, ce temps est marqué par des temporalités multiples et imbriquées. Certaines, plus structurantes et valorisantes, leur permettent d’exercer pleinement leur rôle ; d’autres, plus fragmentées et imprévisibles, peuvent engendrer une surcharge cognitive et un sentiment d’éparpillement. Or, loin d’être une contrainte purement externe, la gestion du temps est également une construction sociale et subjective, influencée par les normes professionnelles et les attentes institutionnelles. Alors, comprendre ces différentes grammaires temporelles et apprendre à les réguler est l'objectif de cet atelier. En objectivant et en déculpabilisant sa relation au temps, nous chercherons à renforcer l’efficacité des cadres et chefs d'établissement, tout en préservant leur équilibre professionnel. Pour ceux-ci en effet, il ne s’agit pas seulement de mieux « gérer » le temps, mais aussi de réinterroger ses usages, d’en identifier les leviers et les zones de tension, et d’ouvrir des marges de manœuvre pour un exercice plus apaisé et efficient de leur fonction
The rise of lichens during the colonization of terrestrial environments
No full textInternational audienceThe origin of terrestrial life and ecosystems fundamentally changed the biosphere. Lichens, symbiotic fungi-algae partnerships, are crucial to nutrient cycling and carbon fixation today, yet their evolutionary history during the evolution of terrestrial ecosystems remains unclear due to a scarce fossil record. We demonstrate that the enigmatic Devonian fossil Spongiophyton from Brazil captures one of the earliest and most widespread records of lichens. The presence of internal hyphae networks, algal cells, possible reproductive structures, calcium oxalate pseudomorphs, abundant nitrogenous compounds, and fossil lipid composition confirms that it was among the first widespread representatives of lichenized fungi in Earth’s history. Spongiophyton abundance and wide paleogeographic distribution in Devonian successions reveal an ecologically prominent presence of lichens during the late stages of terrestrial colonization, just before the evolution of complex forest ecosystems