Structures observed on the spot radiance fields during the FIRE experiment

Three Spot images taken during the FIRE experiment on stratocumulus are analyzed. From this high resolution data detailed observations of the true cloud radiance field may be made. The structure and inhomogeneity of these radiance fields hold important implications for the radiation budget, while the fine scale structure in radiance field provides information on cloud dynamics. Wieliki and Welsh, and Parker et al., have quantified the inhomogeneities of the cumulus clouds through a careful examination of the distribution of cloud (and hole) size as functions of an effective cloud diameter and radiance threshold. Cahalan (1988) has compared for different cloud types of (stratocumulus, fair weather cumulus, convective clouds in the ITCZ) the distributions of clouds (and holes) sizes, the relation between the size and the perimeter of these clouds (and holes), and examining the possibility of scale invariance. These results are extended from LANDSAT resolution (57 m and 30 m) to the Spot resolution (10 m) resolution in the case of boundary layer clouds. Particular emphasis is placed on the statistics of zones of high and low reflectivity as a function of a threshold reflectivity

Full field investigation of salt deformation at room temperature: cooperation of crystal plasticity and grain sliding

International audienceWe observed with optical and scanning electron microscopy halite samples during uniaxial compression. Surface displacement fields were retrieved from digital images taken at different loading stages thanks to digital image correlation (DIC) techniques, on the basis of which we could 1) compute global and local strain fields, 2) identify two co-operational deformation mechanisms. The latter were 1) crystal slip plasticity (CSP), as evidenced by the occurrence of slip lines and computed discrete intracrystalline slip bands at the grain surfaces, 2) interfacial micro-cracking and grain boundary sliding (GBS), as evidenced by the computed relative interfacial displacements. The heterogeneities of the strain fields at the aggregate and at the grain scale, and the local contributions of each mechanism were clearly related to the microstructure, i.e. the relative crystallographic orientations of neighboring grains and the interfacial orientations with respect to the principal stress

Rainfall estimation in the Sahel : the EPSAT-NIGER experiment

Le projet EPSAT-Niger (Estimation des Précipitations par Satellite-expérience Niger) est une expérience destinée à améliorer notre connaissance des systèmes précipitants de l'Afrique soudano-sahélienne, et à mettre au point des algorithmes opérationnels d'estimation des pluies sur cette région. Elle s'appuie sur l'utilisation conjointe d'un réseau de pluviographes (93 postes sur 16.000 km2) et d'un radar météorologique bande C. Sa durée prévue est de trois ans (1990-1992). La géométrie du réseau, une grille régulière dont la maille mesure 12.5 km de côté, dotée d'une cible où la distance entre postes descend à 1 km, a permis de mener à bien des études préliminaires sur la répartition des pluies à différentes échelles de temps et d'espace. Le gradient pluviométrique Sud-Nord des moyennes interannuelles est fortement altéré quand on travaille sur une saison particulière. La variabilité locale des cumuls saisonniers peut être extrêmement importante. Des écarts de 60 % sur moins de 10 km ont été enregistrés. L'exploitation conjointe des données sol et radar conduit à mettre en évidence certaines particularités des lignes de grains et s'avère prometteuse pour mettre au point une vérité sol adaptée à la validation des données satellitaires. (Résumé d'auteur

Automatic cloud screening in NOAA-AVHRR day-time imagery

International audienceWe evaluate how much of the cloud cover can be retrieved using only visible and near infrared informations from a wide-field sensor without thermal infrared channel, such as the projected VEGETATION radiometer of the French Space Agency. AVHRR day-time imagery is used in order to simulate this radiometer. An algorithm is written making only use of the first two AVHRR channels, and is called the WSD algorithm. IN order to assess the accuracy of its retrieval of the cloud cover, its results are compared to what is called a reference algorithm which on the contrary makes use of all spectral channels, and is based upon the published work of Saunders and Kriebel. The main originality of the first test of the WSD algorithm is the combination of dynamic thresholding of both reflectance and ratio histograms in an iterative fashion. It increases the efficiency of the cloud screening in the following ways: increase the number of clouds detected, decrease the number of actually clear pixels declared as cloudy, make the detection rather insensitive to predefined values. The WSD algorithm is completed by a thresholding on the local variance of the AVHRR 2 reflectance over the ocean. The study shows that cloud screening within a single AVHRR image is possible over Western Europe with visible only. For this area, visible range is more efficient for screening than thermal infra-red. Over the desertic soils of Niger, this is no longer true and both wavelength ranges are required for cloud filtering. This study was funded by Centre National d'Etudes Spatiales (CNES)

Mastocytosis in mice expressing human Kit receptor with the activating Asp816Val mutation

Mastocytosis is a rare neoplastic disease characterized by a pathologic accumulation of tissue mast cells (MCs). Mastocytosis is often associated with a somatic point mutation in the Kit protooncogene leading to an Asp/Val substitution at position 816 in the kinase domain of this receptor. The contribution of this mutation to mastocytosis development remains unclear. In addition, the clinical heterogeneity presented by mastocytosis patients carrying the same mutation is unexplained. We report that a disease with striking similarities to human mastocytosis develops spontaneously in transgenic mice expressing the human Asp816Val mutant Kit protooncogene specifically in MCs. This disease is characterized by clinical signs ranging from a localized and indolent MC hyperplasia to an invasive MC tumor. In addition, bone marrow–derived MCs from transgenic animals can be maintained in culture for >24 mo and acquire growth factor independency for proliferation. These results demonstrate a causal link in vivo between the Asp816Val Kit mutation and MC neoplasia and suggest a basis for the clinical heterogeneity of human mastocytosis

SUB-OCEAN: subsea dissolved methane measurements using an embedded laser spectrometer technology

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Environmental Science and Technology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.est.7b06171.We present a novel instrument, the Sub-Ocean probe, allowing in situ and continuous measurements of dissolved methane in seawater. It relies on an optical feedback cavity enhanced absorption technique designed for trace gas measurements and coupled to a patent-pending sample extraction method. The considerable advantage of the instrument compared with existing ones lies in its fast response time of the order of 30 s, that makes this probe ideal for fast and continuous 3D-mapping of dissolved methane in water. It could work up to 40 MPa of external pressure and it provides a large dynamic range, from subnmol of CH4 per liter of seawater to mmol L-1. In this work, we present laboratory calibration of the instrument, intercomparison with standard method and field results on methane detection. The good agreement with the headspace equilibration technique followed by gas-chromatography analysis supports the utility and accuracy of the instrument. A continuous 620-m depth vertical profile in the Mediterranean Sea was obtained within only 10 min and it indicates background dissolved CH4 values between 1 and 2 nmol L-1 below the pycnocline, similar to previous observations conducted in different ocean settings. It also reveals a methane maximum at around 6 m of depth that may reflect local production from bacterial transformation of dissolved organic matter

Laboratoire d’analyse secondaire et de méthodes appliquées à la sociologie

Michel Forsé, directeur de recherche au CNRS avec Yaël Brinbaum, Vérène Chevalier, Evelyne Desbois, Marie-Odile Lebeaux, Florence Maillochon, Sophie Pochic, Roxane Silberman, Marion Selz, chercheurs ou ingénieurs au CNRS et Colin Marchika et Ionela Roharik, ingénieurs au CESTA Méthodes quantitatives en sociologie Conduit sous les auspices du LASMAS-IdL et partie prenante du DEA de sociologie, cet enseignement répond à une demande grandissante de formation en méthodologie quantitative pour les..

Laboratoire d’analyse secondaire et de méthodes appliquées à la sociologie

Michel Forsé, directeur de recherche au CNRSYaël Brinbaum, Vérène Chevalier, Évelyne Desbois, Marie-Odile Lebeaux, Florence Maillochon, Sophie Pochic, Roxane Silberman, Marion Selz, chercheurs ou ingénieurs au CNRSColin Marchika et lonela Roharik, ingénieurs au CESTA Méthodes quantitatives en sociologie Conduit sous les auspices du LASMAS et partie prenante du DEA « sociologie », cet enseignement répond à une demande grandissante de formation en méthodologie quantitative pour les sciences soc..

Laboratoire d’analyse secondaire et de méthodes appliquées à la sociologie

Michel Forsé, directeur de recherche au CNRSYaël Brinbaum, Vérène Chevalier, Évelyne Desbois, Marie-Odile Lebeaux, Florence Maillochon, Sophie Pochic, Roxane Silberman, Marion Selz, chercheurs ou ingénieurs au CNRSColin Marchika et lonela Roharik, ingénieurs au CESTA Méthodes quantitatives en sociologie Conduit sous les auspices du LASMAS et partie prenante du DEA « sociologie », cet enseignement répond à une demande grandissante de formation en méthodologie quantitative pour les sciences soc..

Reemergence of Syphilis in Martinique, 2001–2008

Syphilis reemerged in Martinique in 2004 and initially affected 3 HIV-infected patients. By March 2008, syphilis was diagnosed for 37 men and 18 women. As of October 31, 2009, this outbreak had not yet been brought under control. It initially affected mainly men who had sex with men before it spread to heterosexual persons, minority group members, and crack cocaine users