Sélection des sites et des proies par les Barges à queue noire Limosa limosa islandica s’alimentant sur les herbiers de zoostères et les vasières du centre de la côte atlantique française

Characeae surveys and water physico-chemical studies have been performed during four years (2007-2011) on 41 wetlands of Numidia (NE Algeria). Among the 12 species inventoried in the region, four are rare in North Africa and one, Nitella batrachosperma, is new for Algeria. Comparison between Characeae communities and phosphate contents shows that (1) Characeae have nearly disappeared from habitats that contain high levels of orthophosphates (> 780 μg.l-1), (2) three species of Chara (C. globularis, C. gymnophylla and C. vulgaris) characterize medium-polluted habitats (213-780 μg.l-1), where they are often present as discontinuous populations, and (3) the Nitella (N. opaca and N. translucens) are good indicators of low water pollution (< 70 μg.l-1). In addition to the sole presence of a given species, the physiological appearance of the plants has to be taken into consideration as a sign of a healthy population.Dans une population en expansion, certains individus sont voués à explorer et exploiter de nouveaux habitats de moindre qualité. Sur la façade ouest européenne, la Barge à queue noire Limosa limosa islandica, qui se reproduit exclusivement en Islande, est l’une des rares espèces de limicoles avec une tendance démographique positive. Les côtes françaises accueillent 28 % de la population au milieu de l’hiver, le reste se distribuant sur les îles britanniques et la péninsule ibérique. Contrairement à la Grande Bretagne et l’Irlande, la population française se concentre sur un nombre restreint de sites mais avec de fortes concentrations. Les Pertuis Charentais accueillent plus de 65 % de la population nationale (ca 18 000 individus). Dans cette étude, nous décrivons comment la sélection des proies et les stratégies d’alimentation en milieux intertidaux sont liées à la sélection des sites à l’échelle locale and peuvent expliquer la distribution des oiseaux en période de non reproduction. La sélection des sites et des espèces-proies par les barges a été étudiée par la description du régime alimentaire et de la ressource trophique sur six zones d’alimentation sur les quatre principaux sites hivernages. Dans les Pertuis Charentais, il a été confirmé que ces barges occupent une niche écologique herbivore sur le nouveau site d’hivernage de l’île de Ré, où elles s’alimentent de Zostères naines Zostera noltii. La barge garde un régime carnivore sur les sites continentaux, où elle s’alimente principalement du bivalve Macoma balthica. Sur ces sites, les barges ciblent la proie la plus rentable. À l’exception du dérangement humain, la distribution des individus dans les Pertuis Charentais semble être déterminée par la distribution, l’abondance et l’accessibilité de seulement deux espèces-proies parmi un large éventail d’espèces benthiques

Urban Climate, Human behavior & Energy consumption: from LCZ mapping to simulation and urban planning (the MapUCE project)

International audienceThe MApUCE project aims to integrate in urban policies and most relevant legal documents quantitative data from urban microclimate, climate and energy.The primary objective of this project is to obtain climate and energy quantitative data from numerical simulations, focusing on urban microclimate and building energy consumption in the residential and service sectors, which represents in France 41% of the final energy consumption. Both aspects are coupled as building energy consumption is highly meteorologically dependent (e.g. domestic heating, air-conditioning) and heat waste impact the Urban Heat Island. We propose to develop, using national databases, a generic and automated method for generating Local Climate Zones (LCZ) for all cities in France, including the urban architectural, geographical and sociological parameters necessary for energy and microclimate simulations.As will be presented, previous projects on adaptation of cities to climate change have shown that human behavior is a very potent level to address energy consumption reduction, as much as urban forms or architectural technologies. Therefore, in order to further refine the coupled urban climate and energy consumption calculations, we will develop within TEB (and its Building Energy Module) a model of energy consumer behavior.The second objective of the project is to propose a methodology to integrate quantitative data in urban policies. Lawyers analyze the potential levers in legal and planning documents. A few “best cases” are also studied, in order to evaluate their performances. Finally, based on urban planning agencies requirements, we will define vectors to include quantified energy-climate data to legal urban planning documents. These vectors have to be understandable by urban planners and contain the relevant information.To meet these challenges, the project is organized around strongly interdisciplinary partners in the following fields: law, urban climate, building energetics, architecture, sociology, geography and meteorology, as well as the national federation of urban planning agencies.In terms of results, the cross-analysis of input urban parameters and urban micro-climate-energy simulated data will be available on-line as standardized maps for each of the studied cities. The urban parameter production tool as well as the models will be available as open-source. LCZ and associated urban (and social!) indicators may be integrated within the WUDAPT database

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Reconstruction of Mantle Circulation Using Sequential Data Assimilation

Cette thèse vise à proposer de nouvelles méthodes permettant de reconstruire la circulation dans le manteau terrestre et l'évolution de la tectonique de surface pour les deux cents derniers millions d'années. Nous utilisons des modèles numériques de convection mantellique dans lesquels la dynamique de surface est comparable à la tectonique terrestre. En combinant ces modèles avec des reconstructions de la tectonique des plaques il est possible d'estimerla structure et l'évolution du champ de température dans le manteau. Jusqu'à présent, l'inclusion des reconstructions de la tectonique des plaques se faisait en imposant des conditions aux limites du modèle (équilibre des forces, vitesses imposées...). Ces techniques, bien que permettant de tester la validité de différents scénarios tectoniques alternatifs, n'autorisent pas de rétroaction dynamique de la convection mantellique sur la tectonique de surface.Dans ce travail, nous avons développé des techniques d'assimilation de données permettant d'intégrer les reconstructions de la tectonique des plaques dans un modèle numérique tout en laissant se développer de manière auto-cohérente cette rétroaction. Les techniques développées permettent également de prendre en compte les incertitudes associées aux reconstructions de la tectonique des plaques et de calculer les erreurs sur l'estimation finale de la circulationmantellique.Dans un premier temps, nous avons développé un filtre de Kalman suboptimal qui permet d'estimer la structure et l'évolution de la circulation mantellique la plus probable à partir d'un modèle numérique de convection et d'une sérietemporelle d'observations de surface, ainsi que de leurs incertitudes respectives.Ce filtre a été testé sur des expériences synthétiques. Celles-ci consistent à tenter de retrouver une évolution témoin à partir d'une série temporelle de données issues de cette évolution. Ces expériences ont montré qu'il était possible, enprincipe, de reconstruire la structure et l'évolution de l'ensemble du manteau à partir d'observations de vitesses et de flux de chaleur à la surface.Dans un second temps, nous avons développé un filtre de Kalman d'ensemble. Ce filtre permet non seulement d'estimer de manière plus précise la géométrie des structures mantelliques, mais aussi les incertitudes sur cette estimation.This dissertation focuses on the developpement of data assimilation methods to reconstruct the circulation of the Earth's mantle and the evolution of its surface tectonics for the last 200~Myrs. We use numerical models of mantle convection in which the surface dynamics is similar to the Earth's. By combining these models with plate tectonics reconstructions, it is possible to estimate the structure and evolution of the temperature field of the mantle. So far, the assimilation of plate tectonics reconstructions was done by imposing specific boundary conditions in the model (force balance, imposed velocities...). These techniques, although insightful to test the likeliness of alternative tectonic scenarios, do not allow the full expression of the dynamical feedback between mantle convection and surface tectonics. We develop sequential data assimilation techniques able to assimilate plate tectonics reconstructions in a numerical model while simultaneously letting this dynamicalfeedback develop self-consistently. Moreover, these techniques take into account errors in plate tectonics reconstructions, and compute the error on the final estimation of mantle circulation.First, we develop a suboptimal Kalman filter. This filter estimates the most likely structure and evolution of mantle circulation from a numerical model of mantle convection, a time series of surface observations and the uncertainty on both. This filter was tested on synthetic experiments. The principle of a synthetic experiment is to apply the data assimilation algorithm to a set of synthetic observations obtained from a reference run, and to then compare the obtained estimation of the evolution with the reference evolution. The synthetic experiments we conducted showed that it was possible, in principle, to reconstruct the structure and evolution of the whole mantle from surface velocities and heat flux observations.Second, we develop an Ensemble Kalman Filter. Instead of estimating the most likely evolution, an ensemble of possible evolutions are computed. This technique leads to a better estimation of the geometry of mantle structures and a more complete estimation of the uncertainties associated

Reconstitution de la convection du manteau terrestre par assimilation de données séquentielle

This dissertation focuses on the developpement of data assimilation methods to reconstruct the circulation of the Earth's mantle and the evolution of its surface tectonics for the last 200~Myrs. We use numerical models of mantle convection in which the surface dynamics is similar to the Earth's. By combining these models with plate tectonics reconstructions, it is possible to estimate the structure and evolution of the temperature field of the mantle. So far, the assimilation of plate tectonics reconstructions was done by imposing specific boundary conditions in the model (force balance, imposed velocities...). These techniques, although insightful to test the likeliness of alternative tectonic scenarios, do not allow the full expression of the dynamical feedback between mantle convection and surface tectonics. We develop sequential data assimilation techniques able to assimilate plate tectonics reconstructions in a numerical model while simultaneously letting this dynamicalfeedback develop self-consistently. Moreover, these techniques take into account errors in plate tectonics reconstructions, and compute the error on the final estimation of mantle circulation.First, we develop a suboptimal Kalman filter. This filter estimates the most likely structure and evolution of mantle circulation from a numerical model of mantle convection, a time series of surface observations and the uncertainty on both. This filter was tested on synthetic experiments. The principle of a synthetic experiment is to apply the data assimilation algorithm to a set of synthetic observations obtained from a reference run, and to then compare the obtained estimation of the evolution with the reference evolution. The synthetic experiments we conducted showed that it was possible, in principle, to reconstruct the structure and evolution of the whole mantle from surface velocities and heat flux observations.Second, we develop an Ensemble Kalman Filter. Instead of estimating the most likely evolution, an ensemble of possible evolutions are computed. This technique leads to a better estimation of the geometry of mantle structures and a more complete estimation of the uncertainties associated.Cette thèse vise à proposer de nouvelles méthodes permettant de reconstruire la circulation dans le manteau terrestre et l'évolution de la tectonique de surface pour les deux cents derniers millions d'années. Nous utilisons des modèles numériques de convection mantellique dans lesquels la dynamique de surface est comparable à la tectonique terrestre. En combinant ces modèles avec des reconstructions de la tectonique des plaques il est possible d'estimerla structure et l'évolution du champ de température dans le manteau. Jusqu'à présent, l'inclusion des reconstructions de la tectonique des plaques se faisait en imposant des conditions aux limites du modèle (équilibre des forces, vitesses imposées...). Ces techniques, bien que permettant de tester la validité de différents scénarios tectoniques alternatifs, n'autorisent pas de rétroaction dynamique de la convection mantellique sur la tectonique de surface.Dans ce travail, nous avons développé des techniques d'assimilation de données permettant d'intégrer les reconstructions de la tectonique des plaques dans un modèle numérique tout en laissant se développer de manière auto-cohérente cette rétroaction. Les techniques développées permettent également de prendre en compte les incertitudes associées aux reconstructions de la tectonique des plaques et de calculer les erreurs sur l'estimation finale de la circulationmantellique.Dans un premier temps, nous avons développé un filtre de Kalman suboptimal qui permet d'estimer la structure et l'évolution de la circulation mantellique la plus probable à partir d'un modèle numérique de convection et d'une sérietemporelle d'observations de surface, ainsi que de leurs incertitudes respectives.Ce filtre a été testé sur des expériences synthétiques. Celles-ci consistent à tenter de retrouver une évolution témoin à partir d'une série temporelle de données issues de cette évolution. Ces expériences ont montré qu'il était possible, enprincipe, de reconstruire la structure et l'évolution de l'ensemble du manteau à partir d'observations de vitesses et de flux de chaleur à la surface.Dans un second temps, nous avons développé un filtre de Kalman d'ensemble. Ce filtre permet non seulement d'estimer de manière plus précise la géométrie des structures mantelliques, mais aussi les incertitudes sur cette estimation

Ensemble Kalman filter for the reconstruction of the Earth's mantle circulation

International audienceRecent advances in mantle convection modeling led to the release of a new generation of convection codes, able to self-consistently generate plate-like tectonics at their surface. Those models physically link mantle dynamics to surface tectonics. Combined with plate tectonic reconstructions, they have the potential to produce a new generation of mantle circulation models that use data assimilation methods and where uncertainties in plate tectonic reconstructions are taken into account. We provided a proof of this concept by applying a suboptimal Kalman filter to the reconstruction of mantle circulation (Bocher et al., 2016). Here, we propose to go one step further and apply the ensemble Kalman filter (EnKF) to this problem. The EnKF is a sequential Monte Carlo method particularly adapted to solve high-dimensional data assimilation problems with nonlinear dynamics. We tested the EnKF using synthetic observations consisting of surface velocity and heat flow measurements on a 2-D-spherical annulus model and compared it with the method developed previously. The EnKF performs on average better and is more stable than the former method. Less than 300 ensemble members are sufficient to reconstruct an evolution. We use covariance adaptive inflation and localization to correct for sampling errors. We show that the EnKF results are robust over a wide range of covariance localization parameters. The reconstruction is associated with an estimation of the error, and provides valuable information on where the reconstruction is to be trusted or not

Drawing everyday sexism in academia: Observations and analysis of a community-based initiative

Sexist behaviour in the workplace contributes to create a hostile environment, hindering the chance of women and gender non-conforming individuals to pursue an academic career, but also reinforcing gender stereotypes that are harmful to their progress and recognition. The Did this really happen?! project aims at publishing real-life, everyday sexism in the form of comic strips. Its major goal is to raise awareness about unconscious biases that transpire in everyday interactions in academia and increase the visibility of sexist situations that arise within the scientific community, especially to those who might not notice it. Through the website didthisreallyhappen.net, we collect testimonies about everyday sexism occurring in the professional academic environment (universities, research institutes, scientific conferences…). We translate these stories into comics and publish them anonymously without any judgement or comments on the website. By now, we have collected over 100 testimonies. From this collection, we identified six recurrent patterns: (1) behaviours that aim at maintaining women in stereotypical feminine roles, (2) behaviours that aim at maintaining men in stereotypical masculine roles, (3) the questioning of the scientific skills of female researchers, (4) situations where women have the position of an outsider, especially in informal networking contexts, (5) the objectification of women, and (6) the expression of neosexist views. We first present a detailed analysis of these categories, then we report on the different ways we interact and engage with the Earth science community, the scientific community at large and the public in this project.ISSN:1680-7340ISSN:1680-735

Drawing everyday sexism in academia: observations and analysis of a community-based initiative

International audienceAbstract. Sexist behaviour in the workplace contributes to create a hostile environment, hindering the chance of women and gender non-conforming individuals to pursue an academic career, but also reinforcing gender stereotypes that are harmful to their progress and recognition. The Did this really happen?! project aims at publishing real-life, everyday sexism in the form of comic strips. Its major goal is to raise awareness about unconscious biases that transpire in everyday interactions in academia and increase the visibility of sexist situations that arise within the scientific community, especially to those who might not notice it. Through the website didthisreallyhappen.net, we collect testimonies about everyday sexism occurring in the professional academic environment (universities, research institutes, scientific conferences…). We translate these stories into comics and publish them anonymously without any judgement or comments on the website. By now, we have collected over 100 testimonies. From this collection, we identified six recurrent patterns: (1) behaviours that aim at maintaining women in stereotypical feminine roles, (2) behaviours that aim at maintaining men in stereotypical masculine roles, (3) the questioning of the scientific skills of female researchers, (4) situations where women have the position of an outsider, especially in informal networking contexts, (5) the objectification of women, and (6) the expression of neosexist views. We first present a detailed analysis of these categories, then we report on the different ways we interact and engage with the Earth science community, the scientific community at large and the public in this project