43 research outputs found

    The graphical modeling as a support tool for planning and monitoring sustainable construction projects and public infrastructure

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    International audienceVisual communication through graphical scheduling methods is often the point of failure for the planning and monitoring of construction projects. The proposed chronographic model studies the graphical visual representation of the schedule in the spatial dimension. This model classifies the scheduling entities, especially the activities, the resources and the area of work, into three types of entities. These entity types symbolize the construction operations, establish the relationships between them, and determine the direction of flow of information. Using these entities, the planner can define the graphical approach in order to display the schedule information under diverse, compatible layouts and switch between these layouts. The primary goal is for all stakeholders to have a better understanding of the scheduling logic. This paper describes the meta-model that is used to structure these entities into classes, define their classification criteria with the visual representation of the scheduling approaches, and infer the relationships amongst them. The use of the Entity Relationship (ER) model to create the meta-model ensures uniqueness and stability. The result is the development and implementation of a meta-model that allows the planner to display the schedule information's under diverse approaches, add/edit entities, organize them into classes and infer their behavior towards each other in order to gain a better understanding of their roles. The validation process is done through the generation of the ER conceptual data model, adapted to the Chronographic construction scheduling approach that embraces change while maintaining consistency and self-validation despite the addition of new entities in classes.La communication visuelle par des méthodes de planification graphiques est souvent le point d'échec pour la planification et le contrôle de projets de construction. Le modèle de "chronographique" proposé étudie la représentation visuelle graphique du planning dans l'espace. Ce modèle classifie les entités de planification, particulièrement les activités, les ressources et la zone de travail, dans trois types d'entités. Ces types d'entité symbolisent les opérations de construction, établissent les relations entre elles et déterminent la direction des flux d'informations. En utilisant ces entités, le planificateur peut définir l'approche graphique pour afficher les informations du planning sous des représentations diverses, compatibles et même passer d'une représentation à une autre. Le but principal pour toutes les parties prenantes est d'obtenir une meilleure compréhension de la logique de planification. Cet article décrit le meta-modèle qui est utilisé pour structurer ces entités dans des classes, définir leurs critères de classification avec la représentation visuelle des approches de planification et déduire les relations entre elles. L'utilisation du modèle Entité-Relation (ER) pour créer le meta-modèle, assure l'unicité et la stabilité de cette structure. Le résultat est la mise en œuvre d'un meta-modèle et le développement d'un logiciel qui permet au planificateur d'afficher les informations du planning dans des approches diverses, ajouter/éditer des entités, les organiser dans des classes et déduire leur comportement des unes par rapport aux autres pour obtenir une meilleure compréhension de leurs rôles. Le processus de validation est fait par la génération du modèle conceptuel de données, modèle adapté à la méthode chronographique de construction de planning qui associe la possibilité de changement tout en entretenan la cohérence des informations et l'auto-validation malgré l'ajout de nouvelles entités

    Replication, Pathogenesis and Transmission of Pandemic (H1N1) 2009 Virus in Non-Immune Pigs

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    The declaration of the human influenza A pandemic (H1N1) 2009 (H1N1/09) raised important questions, including origin and host range [1,2]. Two of the three pandemics in the last century resulted in the spread of virus to pigs (H1N1, 1918; H3N2, 1968) with subsequent independent establishment and evolution within swine worldwide [3]. A key public and veterinary health consideration in the context of the evolving pandemic is whether the H1N1/09 virus could become established in pig populations [4]. We performed an infection and transmission study in pigs with A/California/07/09. In combination, clinical, pathological, modified influenza A matrix gene real time RT-PCR and viral genomic analyses have shown that infection results in the induction of clinical signs, viral pathogenesis restricted to the respiratory tract, infection dynamics consistent with endemic strains of influenza A in pigs, virus transmissibility between pigs and virus-host adaptation events. Our results demonstrate that extant H1N1/09 is fully capable of becoming established in global pig populations. We also show the roles of viral receptor specificity in both transmission and tissue tropism. Remarkably, following direct inoculation of pigs with virus quasispecies differing by amino acid substitutions in the haemagglutinin receptor-binding site, only virus with aspartic acid at position 225 (225D) was detected in nasal secretions of contact infected pigs. In contrast, in lower respiratory tract samples from directly inoculated pigs, with clearly demonstrable pulmonary pathology, there was apparent selection of a virus variant with glycine (225G). These findings provide potential clues to the existence and biological significance of viral receptor-binding variants with 225D and 225G during the 1918 pandemic [5]

    Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean

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    International audienceWe examined phytoplankton community responses to natural iron fertilisation at 32 sites over and downstream from the Kerguelen Plateau in the Southern Ocean during the austral spring bloom in October–November 2011. The community structure was estimated from chemical and isotopic measurements (particulate organic carbon – POC; 13C-POC; particulate nitrogen – PN; 15N-PN; and biogenic silica – BSi) on size-fractionated samples from surface waters (300, 210, 50, 20, 5, and 1 μm fractions). Higher values of 13C-POC (vs. co-located 13C values for dissolved inorganic carbon – DIC) were taken as indicative of faster growth rates and higher values of 15N-PN (vs. co-located 15N-NO3 source values) as indicative of greater nitrate use (rather than ammonium use, i.e. higher f ratios).Community responses varied in relation to both regional circulation and the advance of the bloom. Iron-fertilised waters over the plateau developed dominance by very large diatoms (50–210 μm) with high BSi / POC ratios, high growth rates, and significant ammonium recycling (lower f ratios) as biomass built up. In contrast, downstream polar frontal waters with a similar or higher iron supply were dominated by smaller diatoms (20–50 μm) and exhibited greater ammonium recycling. Stations in a deep-water bathymetrically trapped recirculation south of the polar front with lower iron levels showed the large-cell dominance observed on the plateau but much less biomass. Comparison of these communities to surface water nitrate (and silicate) depletions as a proxy for export shows that the low-biomass recirculation feature had exported similar amounts of nitrogen to the high-biomass blooms over the plateau and north of the polar front. This suggests that early spring trophodynamic and export responses differed between regions with persistent low levels vs. intermittent high levels of iron fertilisation

    Complete event-by-event α/γ(β) separation in a full-size TeO2 CUORE bolometer by simultaneous heat and light detection

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    The CUORE project began recently a search for neutrinoless double-beta decay (0νββ0\nu\beta\beta) of 130^{130}Te with a O\mathcal{O}(1 ton) TeO2_2 bolometer array. In this experiment, the background suppression relies essentially on passive shielding, material radiopurity and anti-coincidences. The lack of particle identification in CUORE makes α\alpha decays at the detector surface the dominant background, at the level of \sim0.01 counts/(keV kg y) in the region of interest (QQ-value of 0νββ0\nu\beta\beta of the order of 2.5 MeV). In the present work we demonstrate, for the first time with a CUORE-size (5×\times5×\times5 cm) TeO2_2 bolometer and using the same technology as CUORE for the readout of the bolometric signals, an efficient α\alpha particle discrimination (99.9\%) with a high acceptance of the 0νββ0\nu\beta\beta signal (about 96\%). This unprecedented result was possible thanks to the superior performance (10 eV RMS baseline noise) of a Neganov-Luke-assisted germanium bolometer used to detect a tiny (70 eV) light signal dominated by γ\gamma(β\beta)-induced Cherenkov radiation in the TeO2_2 detector. The obtained results represent a major breakthrough towards the TeO2_2-based version of CUPID, a ton-scale cryogenic 0νββ0\nu\beta\beta experiment proposed as a follow-up to CUORE with particle identification

    Optimizing EDELWEISS detectors for low-mass WIMP searches

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    The physics potential of EDELWEISS detectors for the search of low-mass weakly interacting massive particles (WIMPs) is studied. Using a data-driven background model, projected exclusion limits are computed using frequentist and multivariate analysis approaches, namely, profile likelihood and boosted decision tree. Both current and achievable experimental performances are considered. The optimal strategy for detector optimization depends critically on whether the emphasis is put on WIMP masses below or above ∼5  GeV/c2. The projected sensitivity for the next phase of the EDELWEISS-III experiment at the Modane Underground Laboratory (LSM) for low-mass WIMP search is presented. By 2018 an upper limit on the spin-independent WIMP-nucleon cross section of σSI=7×10−42  cm2 is expected for a WIMP mass in the range 2–5  GeV/c2. The requirements for a future hundred-kilogram-scale experiment designed to reach the bounds imposed by the coherent scattering of solar neutrinos are also described. By improving the ionization resolution down to 50  eVee, we show that such an experiment installed in an even lower background environment (e.g., at SNOLAB) together with an exposure of 1000   kg⋅yr, should allow us to observe about 80 8B neutrino events after discrimination

    Signals induced by charge-trapping in EDELWEISS FID detectors: Analytical modeling and applications

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    The EDELWEISS-III direct dark matter search experiment uses cryogenic HP-Ge detectors Fully covered with Inter-Digitized electrodes (FID). They are operated at low fields (< 1 V/cm), and as a consequence charge-carrier trapping significantly affects both the ionization and heat energy measurements. This paper describes an analytical model of the signals induced by trapped charges in FID detectors based on the Shockley-Ramo theorem. It is used to demonstrate that veto electrodes, initially designed for the sole purpose of surface event rejection, can be used to provide a sensitivity to the depth of the energy deposits, characterize the trapping in the crystals, perform heat and ionization energy corrections and improve the ionization baseline resolutions. These procedures are applied successfully to actual data

    Measurement of the cosmogenic activation of germanium detectors in EDELWEISS-III

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    International audienceWe present a measurement of the cosmogenic activation in the germanium cryogenic detectors of the EDELWEISS III direct dark matter search experiment. The decay rates measured in detectors with different exposures to cosmic rays above ground are converted into production rates of different isotopes. The measured production rates in units of nuclei/kg/day are 82 ±\pm 21 for 3^3H, 2.8 ±\pm 0.6 for 49^{49}V, 4.6 ±\pm 0.7 for 55^{55}Fe, and 106 ±\pm 13 for 65^{65}Zn. These results are the most accurate for these isotopes. A lower limit on the production rate of 68^{68}Ge of 74 nuclei/kg/day is also presented. They are compared to model predictions present in literature and to estimates calculated with the ACTIVIA code

    Improved EDELWEISS-III sensitivity for low-mass WIMPs using a profile likelihood approach

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    We report on a dark matter search for a Weakly Interacting Massive Particle (WIMP) in the mass range mχ∈[4,30]GeV/c2 with the EDELWEISS-III experiment. A 2D profile likelihood analysis is performed on data from eight selected detectors with the lowest energy thresholds leading to a combined fiducial exposure of 496 kg-days. External backgrounds from γ- and β-radiation, recoils from 206Pb and neutrons as well as detector intrinsic backgrounds were modelled from data outside the region of interest and constrained in the analysis. The basic data selection and most of the background models are the same as those used in a previously published analysis based on boosted decision trees (BDT) [1]. For the likelihood approach applied in the analysis presented here, a larger signal efficiency and a subtraction of the expected background lead to a higher sensitivity, especially for the lowest WIMP masses probed. No statistically significant signal was found and upper limits on the spin-independent WIMP-nucleon scattering cross section can be set with a hypothesis test based on the profile likelihood test statistics. The 90 % C.L. exclusion limit set for WIMPs with mχ=4GeV/c2 is 1.6×10-39cm2, which is an improvement of a factor of seven with respect to the BDT-based analysis. For WIMP masses above 15GeV/c2 the exclusion limits found with both analyses are in good agreement
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