Retour d'expérience sur le comportement de matériaux alternatifs en construction routière

Les matériaux alternatifs placés dans différents contextes routiers sont soumis à des contraintes mécaniques, thermiques et hydriques, susceptibles de modifier leurs propriétés physiques et chimiques, donc leur comportement à long terme. Bien que fondamentale, l'analyse du retour d'expérience à partir d'ouvrages routiers réalisés avec des matériaux alternatifs n'a jusqu'à maintenant pas été véritablement réalisée. Peu de données étant disponibles aujourd'hui sur ces ouvrages, un panel de 17 cas d'études français, parmi lesquels des ouvrages classiques et des plots expérimentaux, a été recensé. L'analyse de ces cas comprend la description de la structure de l'ouvrage, des caractéristiques du matériau alternatif utilisé, des facteurs locaux susceptibles d'avoir une influence sur le comportement des matériaux, et des réponses mécaniques et environnementales du matériau et de la structure routière. Des recommandations pour une meilleure conduite de futures expériences sont proposées

Sur des approches logicielles avancées pour le traitement de multiphysiques couplées en mécanique

Les couplages multiphysiques, en particulier dans les matériaux poreux, couvrent de nos jours de plus en plus de domaines d'application. Ces problématiques font en général intervenir de nombreux champs couvrant plusieurs physiques à des échelles de temps et d'espace très différentes. Un des enjeux cruciaux des aspects liés à la modélisation est de facilement et rapidement intégrer les nouveaux modèles dans des logiciels de simulation, afin d'une part de valider les approches, et d'autre part, de proposer en un temps raisonnable des solutions logicielles prédictives adaptées au milieu industriel. Le but de cette communication est de mettre en perspective deux approches de développement logiciel dans le cadre de la modélisation de systèmes multiphysiques complexes, l'une classique et l'autre avancée en orientée objet

A mean-field kinetic lattice gas model of electrochemical cells

We develop Electrochemical Mean-Field Kinetic Equations (EMFKE) to simulate electrochemical cells. We start from a microscopic lattice-gas model with charged particles, and build mean-field kinetic equations following the lines of earlier work for neutral particles. We include the Poisson equation to account for the influence of the electric field on ion migration, and oxido-reduction processes on the electrode surfaces to allow for growth and dissolution. We confirm the viability of our approach by simulating (i) the electrochemical equilibrium at flat electrodes, which displays the correct charged double-layer, (ii) the growth kinetics of one-dimensional electrochemical cells during growth and dissolution, and (iii) electrochemical dendrites in two dimensions.Comment: 14 pages twocolumn, 17 figure

Online Training on Skin Cancer Diagnosis in Rheumatologists: Results from a Nationwide Randomized Web-Based Survey

International audiencePatients with inflammatory rheumatisms, such as rheumatoid arthritis, are more prone to develop skin cancers than the general population, with an additional increased incidence when receiving TNF blockers. There is therefore a need that physicians treating patients affected with inflammatory rheumatisms with TNF blockers recognize malignant skin lesions, requiring an urgent referral to the dermatologist and a potential withdrawal or modification of the immunomodulatory treatment. We aimed to demonstrate that an online training dedicated to skin tumors increase the abilities of rheumatologists to discriminate skin cancers from benign skin tumors. A nationwide randomized web-based survey involving 141 French rheumatologists was conducted. The baseline evaluation included short cases with skin lesion pictures and multiple choice questions assessing basic knowledge on skin cancers. For each case, rheumatologists had to indicate the nature of skin lesion (benign; premalignant/ malignant), their level of confidence in this diagnosis (10-points Likert scale), and the precise dermatological diagnosis among 5 propositions. Different scores were established. After randomization, only one group had access to the online formation consisting in 4 elearning modules on skin tumors, of 15 minutes each (online training group). After reevaluation, the trained and the non-trained group (control group) were compared. The primary end-point was the number of adequate diagnoses of the nature of the skin lesions. The mean number of adequate diagnosis for the benign versus premalignant/malignant nature of the lesions was higher in the online training group (13.4 vs. 11.2 points; p value <0.0001). While the other knowledge scores were also significantly higher, no statistical difference was observed on the level of self-confidence between the 2 groups. In conclusion, the online formation was effective to improve the rheumatologists' ability to diagnose skin cancer

Translation: The relative native

Translation by Julia Sauma and Martin Holbraad of: Viveiros de Castro, Eduardo (2002) "O Nativo Relativo." Mana, vol. 8, no. 1, p. 113-14

Platelet Serotonin Level Predicts Survival in Amyotrophic Lateral Sclerosis

International audienceBACKGROUND: Amyotrophic lateral sclerosis (ALS) is a life-threatening neurodegenerative disease involving upper and lower motor neurons loss. Clinical features are highly variable among patients and there are currently few known disease-modifying factors underlying this heterogeneity. Serotonin is involved in a range of functions altered in ALS, including motor neuron excitability and energy metabolism. However, whether serotoninergic activity represents a disease modifier of ALS natural history remains unknown. METHODOLOGY: Platelet and plasma unconjugated concentrations of serotonin and plasma 5-HIAA, the major serotonin metabolite, levels were measured using HPLC with coulometric detection in a cohort of 85 patients with ALS all followed-up until death and compared to a control group of 29 subjects. PRINCIPAL FINDINGS: Platelet serotonin levels were significantly decreased in ALS patients. Platelet serotonin levels did not correlate with disease duration but were positively correlated with survival of the patients. Univariate Cox model analysis showed a 57% decreased risk of death for patients with platelet serotonin levels in the normal range relative to patients with abnormally low platelet serotonin (p = 0.0195). This protective effect remained significant after adjustment with age, gender or site of onset in multivariate analysis. Plasma unconjugated serotonin and 5-HIAA levels were unchanged in ALS patients compared to controls and did not correlate with clinical parameters. CONCLUSIONS/SIGNIFICANCE: The positive correlation between platelet serotonin levels and survival strongly suggests that serotonin influences the course of ALS disease

Contribution à l'analyse des coques de révolution présentant localement des singularités

Le premier chapitre est une étude bibliographique : - des rappels sur les notions de stabilité des coques, et sur flambage, - des rappels concernant les méthodologies numériques, - une présentation des travaux de recherche portant sur l'utilisation d'éléments d'interface. Dans un deuxième chapitre, les éléments 3D implémentés (DKT 18 et Q4g24) pour rendre possible la modélisation 3D au sein du code de calcul utilisé (STANLAX) sont présentés ainsi que les calculs de validation associés à ces développements. Le troisième chapitre est consacré à la formulation d'une liaison 2D-3D. Deux formulations sont proposées, l'une basée sur une discrétisation tridimensionnelle de l'interface et une autre reposant sur une description axisymétrique par série de Fourier. Enfin, le dernier chapitre présente les calculs réalisés afin de valider les formulation des éléments de liaison proposée.The first chapter is a literature review which includes : - reminders about shell stability concept and shell buckling concept, - reminders about the numerical methods, - a presentation of research works concerning the use of interface elements. In the second chapter, the 3D elements implemented (DKT18 and Q4g24) in the code, in order to make the 3D modeling possible, are presented. The results of the analysis carried out to validate the developments are also presented. The third chapter is dedicated to the formulation of a 2D-3D interface elemnt. Two formulations are proposed. The first one is based on a three-dimensional discretization of the interface and the second one is based on an axisymmetric description by Fourier series. Finally, the last chapter presents the calculations performed in order to validate the proposed interface element formulations.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF