University of Avignon

About: University of Avignon is a education organization based out in Avignon, Provence-Alpes-Côte-d'Azur, France. It is known for research contribution in the topics: Population & Speaker recognition. The organization has 1526 authors who have published 3766 publications receiving 88928 citations.

Fibrés de Green et Régularité des Graphes C 0 -Lagrangiens Invariants par un Flot de Tonelli

Abstract: In this article, we prove different results concerning the regularity of the C0-Lagrangian invariant graphs of the Tonelli flows. For example : in dimension 2 and in the autonomous generic case, we prove that such a graph is in fact C1 on some set with (Lebesgue) full measure; under certain dynamical additional hypothesis, we prove that these graphs are C1.

Two-dimensional strain and twist by vector velocity imaging in adolescents with severe obesity.

Abstract: The prevalence of severe obesity is increasing worldwide in adolescents. Whether it is associated with functional myocardial abnormalities remains largely unknown, potentially because of its frequent association with other cardiovascular risk factors and also use of insensitive techniques to detect subclinical changes in myocardial function. We used 2D vector velocity imaging (VVI) to investigate early changes in left ventricular (LV) myocardial function in youths with isolated severe obesity. Thirty-seven asymptomatic severely obese adolescents free of diabetes and hypertension, and 24 lean controls were enrolled. LV longitudinal, basal, and apical circumferential strain, strain rate (SR), rotations, and LV twist were measured. Obese adolescents had greater LV mass and reduced systolic and early diastolic tissue Doppler imaging (TDI) velocities than lean counterparts. L strain (-24%) and systolic and early diastolic SR were also diminished in the obese, whereas no intergroup differences existed for the circumferential deformation indexes. LV twist was more pronounced in the obese (+1.7°, P < 0.01) on account of greater apical rotation only (4.1 ± 0.9 vs. 5.2 ± 1.2°, P < 0.01), potentially compensating for the loss in longitudinal function. Systolic-diastolic coupling, an important component of early filling and diastolic function, was maintained with severe obesity. No intergroup differences were reported regarding time to peak values for all VVI indexes highlighting that dynamics of strain and twist/untwist along the cardiac cycle was preserved with severe obesity. Isolated severe obesity in adolescents, at a preclinical stage, is associated with changes in myocardial deformation and torsional mechanics that could be in part related to alterations in relaxation and contractility properties of subendocardial fibers.

Signal pluie et traçage par les isotopes stables en Méditerranée occidentale. Exemple de la région avignonnaise (Sud-Est de la France)

Abstract: An isotopic survey of rainwater has been carried out in Avignon during the two periods 1978–1989 and 1997–1998. This monthly study allowed observation of the evolution of rainwater isotopic content during the year and its lack of relation with meteorological parameters, as well as definition of the local relationship between oxygen-18 and deuterium. Moreover, a comparison of the weighted mean isotopic value of rainwater (–6,21‰) with groundwater values provides a first approach to the estimation of the mean regional input function.

Energetic Charged Particles Above Thunderclouds

Abstract: The French government has committed to launch the satellite TARANIS to study transient coupling processes between the Earth’s atmosphere and near-Earth space. The prime objective of TARANIS is to detect energetic charged particles and hard radiation emanating from thunderclouds. The British Nobel prize winner C.T.R. Wilson predicted lightning discharges from the top of thunderclouds into space almost a century ago. However, new experiments have only recently confirmed energetic discharge processes which transfer energy from the top of thunderclouds into the upper atmosphere and near-Earth space; they are now denoted as transient luminous events, terrestrial gamma-ray flashes and relativistic electron beams. This meeting report builds on the current state of scientific knowledge on the physics of plasmas in the laboratory and naturally occurring plasmas in the Earth’s atmosphere to propose areas of future research. The report specifically reflects presentations delivered by the members of a novel Franco-British collaboration during a meeting at the French Embassy in London held in November 2011. The scientific subjects of the report tackle ionization processes leading to electrical discharge processes, observations of transient luminous events, electromagnetic emissions, energetic charged particles and their impact on the Earth’s atmosphere. The importance of future research in this area for science and society, and towards spacecraft protection, is emphasized.

Markov Decision Evolutionary Games

Abstract: We present a class of evolutionary games involving large populations that have many pairwise interactions between randomly selected players. The fitness of a player depends not only on the actions chosen in the interaction but also on the individual state of the players. Players have a finite life time during which they participate in several local interactions and take actions. The actions taken by a player determine not only the immediate fitness but also the transition probabilities to its next individual state. We define and characterize the Evolutionary Stable Strategies for these games and propose a method to compute them. We illustrate the model and results through a networking problem.