595 research outputs found

    Problem solving methods as Lessons Learned System instrumentation into a PLM tool

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    Among the continuous improvement tools of the performance in enterprise, the experience feedback represents undoubtedly an effective lever of progress by offering important prospects for a progression in almost all the industrial sectors. However, several reserves to its use slow down the diffusion of its employment. We are interested in the installation of experience feedback system in a partner enterprise. In this paper, we propose an instrumentation of a Lessons Learned System (LLS) by problem solving methods (PSM) and its integration with a product lifecycle management (PLM). These proposals support an improvement of LLS performance and a facility of his application

    Photofocusing: Light and flow of phototactic microswimmer suspension

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    We explore in this paper the phenomenon of photofocusing: a coupling between flow vorticity and biased swimming of microalgae toward a light source that produces a focusing of the microswimmer suspension. We combine experiments that investigate the stationary state of this phenomenon as well as the transition regime with analytical and numerical modeling. We show that the experimentally observed scalings on the width of the focalized region and the establishment length as a function of the flow velocity are well described by a simple theoretical model

    Proposition d'amélioration d'un systÚme de retour d'expérience

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    L’objet de cette communication est de prĂ©senter des travaux portant sur le dĂ©ploiement d’un systĂšme de retour d’expĂ©rience dans un progiciel PLM (Product Lifecycle Management). Ces travaux sont rĂ©alisĂ©s en partenariat avec la sociĂ©tĂ© Saft Bordeaux, spĂ©cialisĂ©e dans la conception et la fabrication de systĂšmes de batteries complexes. Nous commençons par dĂ©finir la notion de systĂšme de retour d’expĂ©rience avec ses trois phases clefs (capitalisation, traitement et exploitation) qui le composent. Puis, Ă  l’aide d’un audit rĂ©alisĂ© auprĂšs d’une trentaine d’acteurs impliquĂ©s dans le dĂ©veloppement des produits, nous analysons les pratiques et outils actuellement employĂ©s Ă  la Saft. De cette analyse, nous identifions les freins et les attentes des acteurs pour pouvoir rĂ©aliser un retour d’expĂ©rience efficient. Enfin, face Ă  ces rĂ©sultats, nous prĂ©sentons les principes de la solution mise en oeuvre et les intĂ©rĂȘts d’avoir couplĂ© un systĂšme REx (Retour d'ExpĂ©rience) Ă  un PLM. Nous concluons en prĂ©sentant les perspectives importantes qu’offre un tel travail

    On the Adam-Gibbs-Wolynes scenario for the viscosity increase in glasses

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    We reformulate the interpretation of the mean-field glass transition scenario for finite dimensional systems, proposed by Wolynes and collaborators. This allows us to establish clearly a temperature dependent length xi* above which the mean-field glass transition picture has to be modified. We argue in favor of the mosaic state introduced by Wolynes and collaborators, which leads to the Adam-Gibbs relation between the viscosity and configurational entropy of glass forming liquids. Our argument is a mixture of thermodynamics and kinetics, partly inspired by the Random Energy Model: small clusters of particles are thermodynamically frozen in low energy states, whereas large clusters are kinetically frozen by large activation energies. The relevant relaxation time is that of the smallest `liquid' clusters. Some physical consequences are discussed.Comment: 8 page

    UV photodesorption of methanol in pure and CO-rich ices: desorption rates of the intact molecule and of the photofragments

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    Wavelength dependent photodesorption rates have been determined using synchrotron radiation, for condensed pure and mixed methanol ice in the 7 -- 14 eV range. The VUV photodesorption of intact methanol molecules from pure methanol ices is found to be of the order of 10−5^{-5} molecules/photon, that is two orders of magnitude below what is generally used in astrochemical models. This rate gets even lower (<< 10−6^{-6} molecules/photon) when the methanol is mixed with CO molecules in the ices. This is consistent with a picture in which photodissociation and recombination processes are at the origin of intact methanol desorption from pure CH3_3OH ices. Such low rates are explained by the fact that the overall photodesorption process is dominated by the desorption of the photofragments CO, CH3_3, OH, H2_2CO and CH3_3O/CH2_2OH, whose photodesorption rates are given in this study. Our results suggest that the role of the photodesorption as a mechanism to explain the observed gas phase abundances of methanol in cold media is probably overestimated. Nevertheless, the photodesorption of radicals from methanol-rich ices may stand at the origin of the gas phase presence of radicals such as CH3_3O, therefore opening new gas phase chemical routes for the formation of complex molecules.Comment: 13 pages, 2 figures, 1 tabl

    Etude différentielle des protéines membranaires exprimées à la surface de l'hématie infectée par Plasmodium falciparum, en fonction de la symptomatologie

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    La virulence de Plasmodium falciparum est fonction de sa capacité à séquestrer les érythrocytes infectés (iEs) dans les organes profonds de l hÎte. Elle est liée à la mise en place d un trafic protéique conséquent au niveau membranaire et sub-membranaire de l iE. Cet adressage protéique aboutit à l expression d antigÚnes variant de surface, dont P. falciparum Erythrocyte Membrane Protein-1, PfEMP-1. Cet adhésineprésente une affinité pour divers récepteurs de l'hÎte impliqués dans la physiopathologie des formes graves, telles que le paludisme associé à la grossesse (PAM) et le paludisme cérébral (CM). La diversité de liaison de PfEMP-1 est associée à la variabilité de séquence de son domaine extracellulaire. Ce domaine est constitué d une succession de domaines DBL et CIDR en nombre variable. PfEMP-1 est codée par les gÚnes var classifiés en groupes Ups A, B, C, E et B/A, B/C. Des régions de PfEMP-1 constituées d une succession établie de 2 à 4 domaines, nommées Domain Cassette, DC sont retrouvées dans différents isolats. L obtention de données exhaustives par LC-MS/MS a permis d établir un comparatif du protéome membranaire et hypothétique à partir des échantillons PAM et CM en comparaison à des accÚs simples de paludisme (UM). L identification protéique des PfEMP-1 a montré la singularité de l expression d une PfEMP-1 particuliÚre, VAR2CSA chez les PAM. Ces résultats corroborent les analyses des transcrits du gÚne var2csa comme surexprimé chez les PAM, transcrit qu on retrouve également dans les infections de début et de fin de grossesse. Les PfEMP-1 identifiés au sein des CM étaient significativement associés aux groupes Ups A et B/A et la plupart des peptides identifiés étaient associés à la cassette DC8 dont le transcrit était également surexprimé. L analyse de filter-based feature selection a permis d identifier un sous ensemble de 13 et 14 protéines assignées comme protéines membranaires ou hypothétiques, prédictives des formes de paludisme PAM et CM, respectivement. Parmi ces protéines surexprimées chez les PAM, la présence de VAR2CSA valide l approche d analyse. PFI1785w a été identifiée et associée au PAM, quatre autres protéines apparaissent prédictives de cette forme clinique PFB0115w, PFF0325c, PFA_0410w et PF14_0018. Pour les CM, on distingue les protéines PfEMP-2 et antigen-332 comme spécifiques de cette forme clinique. Les autres protéines qui émergent de ce groupe sont des protéines de fonction inconnue, dont trois sont assignées comme des protéines exportées. L obtention et l analyse en LC-MS/MS d extraits protéiques issus d isolats de terrain font l originalité de ce travail et permettent la corrélation entre les données cliniques et biologiques. Cette étude confirme les données de transcrits sur la famille des gÚnes var et suggÚre de nouvelles intéractions protéiques dans le cadre du paludisme associé à la grossesse et cérébral.Plasmodium falciparum is responsible for severe malaria (cerebral malaria, CM and pregnancy associated malaria, PAM). During the intra-erythrocytic maturation of P. falciparum, parasite-derived proteins are expressed, exported and presented at the surface of the infected erythrocyte (iE) membrane. These include Plasmodium falciparum erythrocyte membrane protein-1 (PfEMP-1). PfEMP-1 is a highly polymorphic adherence receptor, variants of which have been assigned to four groups (A-E) based on their sequence homology. Semi-conserved types, defined by tandem runs of specific domains ( domain cassettes (DC)), are also recognized. The PfEMP-1 type expressed determines the iE adherence phenotype, and is associated with the clinical outcome of infection. Parasite isolates from Beninese children or women presenting with, respectively, CM or PAM were collected along with samples from patients with uncomplicated malaria (UM). We assessed the transcript level of var genes by RT-qPCR and the expression of membrane and hypothetical proteins of Plasmodium by LC-MS/MS. Obtaining LC-MS/MS data enabled a comparison of hypothetical and membrane proteome samples from PAM and CM for comparison with UM samples. The proteomics-based identification of PfEMP-1 showed the expression of a particular PfEMP-1, VAR2CSA, in PAM isolates. These results corroborate the analysis of gene transcripts showing that var2csa is overexpressed in PAM, with transcripts found in isolates from infections both early and late in pregnancy. The PfEMP-1 variants identified in CM samples were predominantly from the Ups groups A and B/A, and most of the peptides identified by LC-MS/MS were associated with the DC8 cassette for which the transcripts were also overexpressed. Analysis using filter-based feature selection identified subsets of 13 and 14 proteins, assigned either as hypothetical or membrane proteins that were predictive of PAM and CM syndromes respectively. The presence of VAR2CSA amongst the proteins overexpressed in PAM samples validates the analytical approach. PFI1785w has previously been identified and associated with the PAM, whilst four other proteins, PFB0115w, PFF0325c, PFA_0410w and PF14_0018, appear to be also predictive of the syndrome. PfEMP-2 protein and antigen-332 were found to be specifically expressed in CM samples. Three other proteins, assigned as exported but with unknown function, were also associated with CM samples. Obtaining and analyzing LC-MS/MS-derived data from protein extracts of field isolates represents the originality of this work and it allowed the identification of correlations between clinical and biological data. This study confirms the transcriptional data relating to the var gene family and provides evidence of new protein interactions in the context both of malaria associated with pregnancy and of cerebral malaria.PARIS5-Bibliotheque electronique (751069902) / SudocPARIS-BIUM-Bib. électronique (751069903) / SudocSudocFranceF

    One year OSIRHYS IV project synthesis: mechanical behaviour of 700 bar type iv high pressure vessel code qualification.

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    International audienceIn this paper we present results of the OSIRHYS IV French project which aims to develop andvalidate models and methods for composite high pressure design and optimization withbehavior uncertainties knowledge. Models of the five partners of this project are presentedand burst simulation results are compared for three test temperatures (-40°C, 15°C and85°C)
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