Search results for "RAV"
showing 10 items of 5866 documents
Travailler avec le modèle
2012
International audience
Sur l’ontologie de Marx. Auto-production, travail aliéné et capital
2014
International audience
Development of acoustic devices functionalized with cobalt corroles or metalloporphyrines for the detection of carbon monoxide at low concentration
2012
International audience; Progresses in synthetic chemistry methodologies has pushed to develop a large variety of artificial receptors of particular interest for chemical sensor applications. We investigate here the behavior of gas sensors based on surface acoustic wave (SAW) devices. The use of Love waves that are specially sensitive to surface perturbation enables to exploit the molecular recognition processes occurring in non conductive sensing layers of cobalt corroies [5,10,15-Tris(2,6-dichlorophenyl)corrolato]cobalt(III)] for CO detection. We have monitored phase variations of Love-wave-based delay lines under various operation conditions and studied the detection efficiency of a diffe…
A Semantic-based Recommender System Using A Simulated Annealing Algorithm
2010
International audience; A recommender system based on semantic web technologies and on an adaptive hypermedia architecture is shown in this paper. The system uses a stochastic algorithm to provide recommendations to users. The paper presents the system architecture based on the semantic Web technologies and explains a simulated annealing algorithm performing the recommendations. A mobile application for the tourism domain proving the feasibility of this system is described at the end of the paper, some benchmarks are presented. In this application, the recommendations are defined as combinations of tourism products, which are linked to each other. The paper is mainly focused on the architec…
Cosmologie des théories de gravite modifiées
2017
The study of physical cosmology has reached an exciting era. For the first time in human history, a quantitative model for the formation and the evolution of the Universe exists, which explains a wide range of phenomena and has been tested with incredible accuracy during the last century. Moreover, weare approaching a time when a bounty of high quality cosmological data will be available,allowing us to use cosmology as a tool to test fundamental physics.In particular, as the large-scale structures of the Universe are governed by gravity, cosmology can help us to asses the correctness of Albert Einstein’s general relativity. This idea fueledmost of the work described in this manuscript,in wh…
Identifying clouds over the Pierre Auger Observatory using infrared satellite data
2013
We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud. identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km(2) of the Pierre Auger Observatory twice per hour with a spatial resolution of similar to 2.4 km by similar to 5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories. (C) 2013 Elsevier B.V. All rights reserved.
γ-ray induced GeODC(II) centers in germanium doped α-quartz crystal
2011
International audience; Main luminescence of α-quartz crystal doped with germanium results from the luminescence of a self-trapped exciton (STE) near germanium. In as grown Ge-doped α-quartz crystal, the luminescence associated with the twofold coordinated Ge center (GeODC) in amorphous silica glass doped with germanium, was never observed. In this work, we performed experiments to investigate if a GeODC like luminescence could appear after a γ-irradiation of a Ge-doped α-quartz crystal. The answer is positive: under excitation with pulsed light of an ArF laser (193 nm): a new luminescence with two bands -- a blue one associated to a time constant of about 100 μs appears and another one wit…
Radiation-induced defects in fluorine-doped silica-based optical fibers: Influence of a pre-loading with H2
2009
International audience; We investigated the effects of 10-keV X-ray radiation on the transmission properties of F-doped optical fibers in the 200–850 nm range of wavelengths (1.5–6 eV). We also studied the influence of pre-loading this kind of fibers with hydrogen on its radiation sensitivity. Our results showed that, for our experimental conditions (pre-treatment with H2 several months before irradiation with diffusion of all the H2 out the fiber core and cladding before X-ray exposure), this pre-treatment increases the radiation-induced attenuation in the ultraviolet part (200–300 nm) of the spectrum. A previous H2-loading has no influence at greater wavelengths. The nature of the radiati…
Influence du paysage et des abondances de bioagresseurs sur l’utilisation de produits phytosanitaires en grandes cultures
2022
Dans cette étude, nous avons cherché à identifier les déterminants des abondances de bioagresseurs à l’échelle nationale, en mobilisant les données EPIPHYT, collectées dans le cadre du BSV, Bulletin de Santé du Végétal. Les niveaux d’occurrence de trois types de bioagresseurs (les limaces, les pucerons des céréales, et les ravageurs du colza) ont été analysées pour l’année 2018 afin d’identifier le poids relatif du climat et du paysage dans leurs niveaux d’occurrence, au grain spatial de la Petite Région Agricole (PRA). Les données de paysage ont été générées par agrégation de plusieurs bases de données d’occupation du sols (BD TOPO, RPG, OSO). L’approche statistique utilisée est une analys…
Inférence de la résistance du paysage au flux de gènes à l'aide de modèles gravitaires intégrant des variables intra-populationnelles
2021
International audience; Modéliser les mouvements de dispersion nécessite d'associer aux éléments paysagers des valeurs de coût caractérisant leur résistance aux déplacements. En landscape genetics, l'inférence de ces valeurs se fait à partir de mesures de différenciation génétique entre populations. Bien que l'hétérogénéité spatiale des tailles de populations puisse aussi influencer de façon significative la différenciation génétique, les variables intra-populationnelles sont rarement prises en compte dans ce type d'inférence. Nous avons étudié à quel point la prise en compte de ces variables pouvait améliorer l'inférence des coûts. Pour cela, nous avons simulé des flux de gènes entre 60 po…