169 research outputs found

    Utilisation de la grille pour la simulation de température de brillance dans une atmosphÚre nuageuse composée de cirrus

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    Utilisation de la grille pour la simulation de température de brillance dans une atmosphÚre nuageuse composée de cirru

    L’indemnisation des victimes d’accidents de la circulation en Europe

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    International audienceÀ une Ă©poque oĂč, Ă  l’intĂ©rieur de l’Union europĂ©enne, la circulation automobile s’effectue pratiquement sans obstacle d’un pays Ă  l’autre, et oĂč les frontiĂšres sont presque invisibles, il peut paraĂźtre paradoxal que les rĂšgles d’indemnisation des victimes d’accidents automobiles restent profondĂ©ment diffĂ©rentes d’un pays Ă  l’autre. Alors que certains pays ont mis en place des rĂ©gimes d’indemnisation spĂ©cifiques, d’autres continuent d’appliquer les rĂšgles du droit commun de la responsabilitĂ© civile, plus ou moins favorables aux victimes.Le prĂ©sent ouvrage, issu d’un sĂ©minaire organisĂ© Ă  Luxembourg les 14 et 15 dĂ©cembre 2012 par le Groupe europĂ©en de recherche sur la responsabilitĂ© civile et l’assurance (GRERCA) avec le concours du Groupe de droit privĂ© europĂ©en de l’UniversitĂ© du Luxembourg, dresse pour la premiĂšre fois un Ă©tat des lieux mettant en Ă©vidence les ressemblances et les divergences en la matiĂšre entre les principaux droits nationaux des pays d’Europe, tant en ce qui concerne les conditions et l’étendue du droit Ă  indemnisation que la mise en oeuvre procĂ©durale et le rĂŽle de l’assurance. Les prĂ©sentations thĂ©oriques des diffĂ©rents systĂšmes sont illustrĂ©es par la rĂ©solution comparative d’un certain nombre de cas pratiques

    Comprehensive tool for calculation of radiative fluxes: illustration of shortwave aerosol radiative effect sensitivities to the details in aerosol and underlying surface characteristics

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    The evaluation of aerosol radiative effect on broadband hemispherical solar flux is often performed using simplified spectral and directional scattering characteristics of atmospheric aerosol and underlying surface reflectance. In this study we present a rigorous yet fast computational tool that accurately accounts for detailed variability of both spectral and angular scattering properties of aerosol and surface reflectance in calculation of direct aerosol radiative effect. The tool is developed as part of the GRASP (Generalized Retrieval of Aerosol and Surface Properties) project. We use the tool to evaluate instantaneous and daily average radiative efficiencies (radiative effect per unit aerosol optical thickness) of several key atmospheric aerosol models over different surface types. We then examine the differences due to neglect of surface reflectance anisotropy, nonsphericity of aerosol particle shape and accounting only for aerosol angular scattering asymmetry instead of using full phase function. For example, it is shown that neglecting aerosol particle nonsphericity causes mainly overestimation of the aerosol cooling effect and that magnitude of this overestimate changes significantly as a function of solar zenith angle (SZA) if the asymmetry parameter is used instead of detailed phase function. It was also found that the nonspherical–spherical differences in the calculated aerosol radiative effect are not modified significantly if detailed BRDF (bidirectional reflectance distribution function) is used instead of Lambertian approximation of surface reflectance. Additionally, calculations show that usage of only angular scattering asymmetry, even for the case of spherical aerosols, modifies the dependence of instantaneous aerosol radiative effect on SZA. This effect can be canceled for daily average values, but only if sun reaches the zenith; otherwise a systematic bias remains. Since the daily average radiative effect is obtained by integration over a range of SZAs, the errors vary with latitude and season. In summary, the present analysis showed that use of simplified assumptions causes systematic biases, rather than random uncertainties, in calculation of both instantaneous and daily average aerosol radiative effect. Finally, we illustrate application of the rigorous aerosol radiative effect calculations performed as part of GRASP aerosol retrieval from real POLDER/PARASOL satellite observations

    ModĂšle de comportement communicatif conventionnel pour un agent en interaction avec des humains (Approche par jeux de dialogue)

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    Cette thĂšse a pour objectif l amĂ©lioration des capacitĂ©s communicatives des agents logiciels en interaction avec des humains. Dans ce but, nous proposons une mĂ©thodologie basĂ©e sur l Ă©tude d un corpus d interactions Homme-Homme orientĂ©es vers la rĂ©alisation d une tĂąche. Nous proposons un cadre qui s appuie sur les jeux de dialogue afin de modĂ©liser des motifs dialogiques observĂ©s. Nous illustrons la spĂ©cification de tels jeux depuis des motifs extraits en appliquant l'ensemble des Ă©tapes de noter mĂ©thodologie Ă  un corpus. Les jeux spĂ©cifiĂ©s sont validĂ©s en montrant qu ils dĂ©crivent de façon appropriĂ©e les motifs apparaissant dans le corpus de rĂ©fĂ©rence. Enfin, nous montrons l intĂ©rĂȘt interprĂ©tatif et gĂ©nĂ©ratif de notre modĂšle pour le fondement du comportement communicatif conventionnel d un agent interagissant avec un humain. Nous implĂ©mentons ce modĂšle dans le module Dogma, exploitable par un agent dans un dialogue impliquant deux interlocuteurs.This research work aims at improving the communicative behaviour of software agents interacting with humans. To this purpose, we present a data-driven methodology based on the study of a task oriented corpus consisting of Human-Human interactions. We present a framework to specify dialogue games from observed interaction patterns based on the notion of social commitments and conversational gameboard. We exemplify the specification of dialogue games by implementing all the steps of our methodology ona task-oriented corpus. The produced games are validated by showing that they appropriately describe the patterns appearing in a reference corpus. Eventually, we show that an agent can take advantage of our model to regulate its conventional communicative behaviour on both interpretative and generative levels. We implement this model into Dogma, a module that can be used by an agent to manage its communicative behaviour in a two-interlocutor dialogue.ROUEN-INSA Madrillet (765752301) / SudocSudocFranceF

    Effects of mixing state on optical and radiative properties of black carbon in the European Arctic

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    Atmospheric aging promotes internal mixing of black carbon (BC), leading to an enhancement of light absorption and radiative forcing. The relationship between BC mixing state and consequent absorption enhancement was never estimated for BC found in the Arctic region. In the present work, we aim to quantify the absorption enhancement and its impact on radiative forcing as a function of microphysical properties and mixing state of BC observed in situ at the Zeppelin Arctic station (78 degrees N) in the spring of 2012 during the CLIMSLIP (Climate impacts of short-lived pollutants in the polar region) project. Single-particle soot photometer (SP2) measurements showed a mean mass concentration of refractory black carbon (rBC) of 39 ngm(-3), while the rBC mass size distribution was of lognormal shape, peaking at an rBC mass-equivalent diameter (D-rBC) of around 240 nm. On average, the number fraction of particles containing a BC core with D-rBC > 80 nm was less than 5% in the size range (overall optical particle diameter) from 150 to 500 nm. The BC cores were internally mixed with other particulate matter. The median coating thickness of BC cores with 220 nm <D-rBC <260 nm was 52 nm, resulting in a core-shell diameter ratio of 1.4, assuming a coated sphere morphology. Combining the aerosol absorption coefficient observed with an Aethalometer and the rBC mass concentration from the SP2, a mass absorption cross section (MAC) of 9.8 m(2) g(-1) was inferred at a wavelength of 550 nm. Consistent with direct observation, a similar MAC value (8.4m(2) g(-1) at 550 nm) was obtained indirectly by using Mie theory and assuming a coated-sphere morphology with the BC mixing state constrained from the SP2 measurements. According to these calculations, the lensing effect is estimated to cause a 54% enhancement of the MAC compared to that of bare BC particles with equal BC core size distribution. Finally, the ARTDECO radiative transfer model was used to estimate the sensitivity of the radiative balance to changes in light absorption by BC as a result of a varying degree of internal mixing at constant total BC mass. The clear-sky noontime aerosol radiative forcing over a surface with an assumed wavelength-dependent albedo of 0.76-0.89 decreased, when ignoring the absorption enhancement, by -0.12 Wm(-2) compared to the base case scenario, which was constrained with mean observed aerosol properties for the Zeppelin site in Arctic spring. The exact magnitude of this forcing difference scales with environmental conditions such as the aerosol optical depth, solar zenith angle and surface albedo. Nevertheless, our investigation suggests that the absorption enhancement due to internal mixing of BC, which is a systematic effect, should be considered for quantifying the aerosol radiative forcing in the Arctic region.Peer reviewe

    NS2 Protein of Hepatitis C Virus Interacts with Structural and Non-Structural Proteins towards Virus Assembly

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    Growing experimental evidence indicates that, in addition to the physical virion components, the non-structural proteins of hepatitis C virus (HCV) are intimately involved in orchestrating morphogenesis. Since it is dispensable for HCV RNA replication, the non-structural viral protein NS2 is suggested to play a central role in HCV particle assembly. However, despite genetic evidences, we have almost no understanding about NS2 protein-protein interactions and their role in the production of infectious particles. Here, we used co-immunoprecipitation and/or fluorescence resonance energy transfer with fluorescence lifetime imaging microscopy analyses to study the interactions between NS2 and the viroporin p7 and the HCV glycoprotein E2. In addition, we used alanine scanning insertion mutagenesis as well as other mutations in the context of an infectious virus to investigate the functional role of NS2 in HCV assembly. Finally, the subcellular localization of NS2 and several mutants was analyzed by confocal microscopy. Our data demonstrate molecular interactions between NS2 and p7 and E2. Furthermore, we show that, in the context of an infectious virus, NS2 accumulates over time in endoplasmic reticulum-derived dotted structures and colocalizes with both the envelope glycoproteins and components of the replication complex in close proximity to the HCV core protein and lipid droplets, a location that has been shown to be essential for virus assembly. We show that NS2 transmembrane region is crucial for both E2 interaction and subcellular localization. Moreover, specific mutations in core, envelope proteins, p7 and NS5A reported to abolish viral assembly changed the subcellular localization of NS2 protein. Together, these observations indicate that NS2 protein attracts the envelope proteins at the assembly site and it crosstalks with non-structural proteins for virus assembly

    The search for translational pain outcomes to refine analgesic development: Where did we come from and where are we going?

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    Pain measures traditionally used in rodents record mere reflexes evoked by sensory stimuli; the results thus may not fully reflect the human pain phenotype. Alterations in physical and emotional functioning, pain-depressed behaviors and facial pain expressions were recently proposed as additional pain outcomes to provide a more accurate measure of clinical pain in rodents, and hence to potentially enhance analgesic drug development. We aimed to review how preclinical pain assessment has evolved since the development of the tail flick test in 1941, with a particular focus on a critical analysis of some nonstandard pain outcomes, and a consideration of how sex differences may affect the performance of these pain surrogates. We tracked original research articles in Medline for the following periods: 1973-1977, 1983-1987, 1993-1997, 2003-2007, and 2014-2018. We identified 606 research articles about alternative surrogate pain measures, 473 of which were published between 2014 and 2018. This indicates that preclinical pain assessment is moving toward the use of these measures, which may soon become standard procedures in preclinical pain laboratories.FPU grant from the Spanish Ministry of Education, Culture and SportsSpanish Ministry of Economy and Competitiveness (MINECO, grant SAF2016-80540-R)RamĂłn Areces FoundationJunta de AndalucĂ­a (grant CTS 109)Esteve PharmaceuticalsEuropean Regional Development Fund (ERDF
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