Simulating the midlatitude atmospheric circulation: what might we gain from high-resolution modeling of air-sea interactions?

Purpose of Review. To provide a snapshot of the current research on the oceanic forcing of the atmospheric circulation in midlatitudes and a concise update on previous review papers. Recent findings. Atmospheric models used for seasonal and longer timescales predictions are starting to resolve motions so far only studied in conjunction with weather forecasts. These phenomena have horizontal scales of ~ 10–100 km which coincide with energetic scales in the ocean circulation. Evidence has been presented that, as a result of this matching of scale, oceanic forcing of the atmosphere was enhanced in models with 10–100 km grid size, especially at upper tropospheric levels. The robustness of these results and their underlying mechanisms are however unclear. Summary. Despite indications that higher resolution atmospheric models respond more strongly to sea surface temperature anomalies, their responses are still generally weaker than those estimated empirically from observations. Coarse atmospheric models (grid size greater than 100 km) will miss important signals arising from future changes in ocean circulation unless new parameterizations are developed

LRCH Proteins: A Novel Family of Cytoskeletal Regulators

Background: Comparative genomics has revealed an unexpected level of conservation for gene products across the evolution of animal species. However, the molecular function of only a few proteins has been investigated experimentally, and the role of many animal proteins still remains unknown. Here we report the characterization of a novel family of evolutionary conserved proteins, which display specific features of cytoskeletal scaffolding proteins, referred to as LRCHs. Principal Findings: Taking advantage of the existence of a single LRCH gene in flies, dLRCH, we explored its function in cultured cells, and show that dLRCH act to stabilize the cell cortex during cell division. dLRCH depletion leads to ectopic cortical blebs and alters positioning of the mitotic spindle. We further examined the consequences of dLRCH deletion throughout development and adult life. Although dLRCH is not essential for cell division in vivo, flies lacking dLRCH display a reduced fertility and fitness, particularly when raised at extreme temperatures. Conclusion/Significance: These results support the idea that some cytoskeletal regulators are important to buffer environmental variations and ensure the proper execution of basic cellular processes, such as the control of cell shape

A SARS-CoV-2 protein interaction map reveals targets for drug repurposing

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 2.3 million people, killed over 160,000, and caused worldwide social and economic disruption1,2. There are currently no antiviral drugs with proven clinical efficacy, nor are there vaccines for its prevention, and these efforts are hampered by limited knowledge of the molecular details of SARS-CoV-2 infection. To address this, we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), identifying 332 high-confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (29 FDA-approved drugs, 12 drugs in clinical trials, and 28 preclinical compounds). Screening a subset of these in multiple viral assays identified two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the Sigma1 and Sigma2 receptors. Further studies of these host factor targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19

Storm Track Response to Oceanic Eddies in Idealized Atmospheric Simulations

International audienceLarge-scale oceanic fronts, such as in western boundary currents, have been shown to play an important role in the dynamics of atmospheric storm tracks. Little is known about the influence of mesoscale oceanic eddies on the free troposphere, although their imprint on the atmospheric boundary layer is well documented. The present study investigates the response of the tropospheric storm track to the presence of sea surface temperature (SST) anomalies associated with an eddying ocean. Idealized experiments are carried out in a configuration of a zonally reentrant channel representing the midlatitudes. The SST field is composed of a large-scale zonally symmetric front to which are added mesoscale eddies localized close to the front. Numerical simulations show a robust signal of a poleward shift of the storm track and of the tropospheric eddy-driven jet when oceanic eddies are taken into account. This is accompanied by more intense air–sea fluxes and convective heating above oceanic eddies. Also, a mean heating of the troposphere occurs poleward of the oceanic eddying region, within the storm track. A heat budget analysis shows that it is caused by a stronger diabatic heating within storms associated with more water advected poleward. This additional heating affects the baroclinicity of the flow, which pushes the jet and the storm track poleward

Les indicateurs DCE estuariens : Etat des lieux à l'échelle européenne en avril 2009, mise à jour en décembre 2010 - Rapport

[Departement_IRSTEA]Eaux [TR1_IRSTEA]QUASARE [Relecteur_IRSTEA]Bagot, C. ; Bruchon, F. ; Dauvin, J.C. ; Desroy, N. ; Fisson, C. ; Lévêque, C. ; Ruellet, T. ; Sottolichio, A.La Directive européenne Cadre sur l'Eau (DCE Directive 2000/60/CE) vise à atteindre le « bon état » écologique et chimique des masses d'eau souterraine et de surface, ou le « bon potentiel » pour les Masses d'Eau de surface Fortement Modifiées (MEFM), d'ici à 2015. L'évaluation de l'état des masses d'eau de surface dites « de transition », telles que les estuaires, se fait via l'utilisation d'indicateurs biologiques (basés sur le phytoplancton, la flore aquatique, les invertébrés benthiques et l'ichtyofaune), chimiques et hydromorphologiques (Directive 2000/60/CE). Le développement de ces indicateurs est à la charge de chaque Etat Membre et pose aujourd'hui encore de nombreuses questions. En France, le projet BEEST - « Vers une approche multicritère du Bon Etat/potentiel écologique des grands Estuaires atlantiques Seine, Loire et Gironde » - est un projet national de recherche appliquée, multipartenarial et interdisciplinaire, qui a pour objectif principal d'appuyer les gestionnaires français dans la mise en place de la DCE sur ces trois estuaires. Il est co-financé par le MEEDDAT (Ministère de l'Energie, de l'Ecologie, du Développement Durable et de l'Aménagement du Territoire), l'ONEMA (Office National de l'Eau et des Milieux Aquatiques) et des partenaires locaux des trois estuaires : le GIP Seine-Aval, le GIP Loire Estuaire et le SMIDDEST. La présente synthèse, qui porte sur les indicateurs DCE estuariens à l'échelle européenne, se place dans le cadre du projet BEEST et a pour objectifs : (i) d'identifier les questions clefs sur lesquelles la dynamique française rencontre encore des problèmes pour la création d'indicateurs DCE en estuaires de Seine, Loire et Gironde, (ii) de rechercher comment ces questions ont été traitées par les autres Etats Membres et si possible d'identifier des pistes de solution et/ou des contacts clefs sur lesquels les équipes françaises qui le souhaitent pourront s'appuyer, (iii) de présenter, à l'échelle européenne, une synthèse claire et succincte des démarches d'élaboration des indicateurs DCE estuariens, de leur état d'avancement, ainsi qu'une liste des principaux contacts et références bibliographiques, et enfin (iv) d'apporter ainsi des éléments au projet BEEST et plus largement au groupe national DCE eaux littorales pour faire les meilleurs choix en matière d'élaboration d'indicateurs estuariens. Afin de répondre au mieux aux questions posées, cette synthèse se focalise sur les pays de l'écorégion Atlantique Nord-Est telle que définie par l'Union Européenne (Anonyme, 2007b), et qui possèdent des masses d'eau de transition estuariennes : Allemagne, Belgique, Pays-Bas, Portugal, Espagne, Irlande, Royaume-Uni et France. L'ensemble des paramètres biologiques cités précédemment, les paramètres physico-chimiques généraux (Directive 2000/60/CE), et les paramètres hydromorphologiques sont étudiés. Pour chacun d'entre eux, les éléments suivants sont présentés : (i) un bref rappel des exigences DCE vis-à-vis de cet indicateur, (ii) son état d'avancement en France ainsi que les principaux problèmes rencontrés pour sa construction et/ou son utilisation en Seine, Loire et Gironde, (iii) un état des lieux des démarches adoptées par les autres Etats Membres, et éventuellement (iv) un approfondissement sur quelques points jugés pertinents. Enfin, quelques points de discussion ainsi que des perspectives de travail ressortant de cette étude sont présentés

Response of Surface Wind Divergence to Mesoscale SST Anomalies under Different Wind Conditions

International audienceThe response of the atmospheric boundary layer to mesoscale sea surface temperature (SST) is often characterized by a link between wind stress divergence and downwind SST gradients. In this study, an idealized simulation representative of a storm track above a prescribed stationary SST field is examined in order to determine in which background wind conditions that relationship occurs. The SST field is composed of a midlatitude large-scale frontal zone and mesoscale SST anomalies. It is shown that the divergence of the surface wind can correlate either with the Laplacian of the atmospheric boundary layer temperature or with the downwind SST gradient. The first case corresponds to background situations of weak winds or of unstable boundary layers, and the response is in agreement with an Ekman balance adjustment in the boundary layer. The second case corresponds to background situations of stable boundary layers, and the response is in agreement with downward mixing of momentum. Concerning the divergence of the wind stress, it generally resembles downwind SST gradients for stable and unstable boundary layers, in agreement with past studies. For weak winds, a correlation with the temperature Laplacian is, however, found to some extent. In conclusion, our study reveals the importance of the large-scale wind conditions in modulating the surface atmospheric response with different responses in the divergences of surface wind and wind stress