Dissipation of vibration in rough contact

The relationship which links the normal vibration occurring during the sliding of rough surfaces and the nominal contact area is investigated. Two regimes are found. In the first one, the vibrational level does not depend on the contact area, while in the second one, it is propor- tional to the contact area. A theoretical model is proposed. It is based on the assumption that the vibrational level results from a competition between two processes of vibration damping, the internal damping of the material and the contact damping occurring at the interface

Environmental Factors Influence Language Development in Children with Autism Spectrum Disorders

International audienc

Chronic kidney disease in children: the global perspective

In contrast to the increasing availability of information pertaining to the care of children with chronic kidney disease (CKD) from large-scale observational and interventional studies, epidemiological information on the incidence and prevalence of pediatric CKD is currently limited, imprecise, and flawed by methodological differences between the various data sources. There are distinct geographic differences in the reported causes of CKD in children, in part due to environmental, racial, genetic, and cultural (consanguinity) differences. However, a substantial percentage of children develop CKD early in life, with congenital renal disorders such as obstructive uropathy and aplasia/hypoplasia/dysplasia being responsible for almost one half of all cases. The most favored end-stage renal disease (ESRD) treatment modality in children is renal transplantation, but a lack of health care resources and high patient mortality in the developing world limits the global provision of renal replacement therapy (RRT) and influences patient prevalence. Additional efforts to define the epidemiology of pediatric CKD worldwide are necessary if a better understanding of the full extent of the problem, areas for study, and the potential impact of intervention is desired

Epidemiology of chronic kidney disease in children

In the past 30 years there have been major improvements in the care of children with chronic kidney disease (CKD). However, most of the available epidemiological data stem from end-stage renal disease (ESRD) registries and information on the earlier stages of pediatric CKD is still limited. The median reported incidence of renal replacement therapy (RRT) in children aged 0–19 years across the world in 2008 was 9 per million of the age-related population (4–18 years). The prevalence of RRT in 2008 ranged from 18 to 100 per million of the age-related population. Congenital disorders, including congenital anomalies of the kidney and urinary tract (CAKUT) and hereditary nephropathies, are responsible for about two thirds of all cases of CKD in developed countries, while acquired causes predominate in developing countries. Children with congenital disorders experience a slower progression of CKD than those with glomerulonephritis, resulting in a lower proportion of CAKUT in the ESRD population compared with less advanced stages of CKD. Most children with ESRD start on dialysis and then receive a transplant. While the survival rate of children with ERSD has improved, it remains about 30 times lower than that of healthy peers. Children now mainly die of cardiovascular causes and infection rather than from renal failure

Development of Boron Coatings for antenna protection limiters in the WEST Tokamak

During the upgrade of Tore Supra to transform the machine into a fully metallic plasma facing environment (WEST), the Antennae Protection Limiters (APL), originally made in CFC, have been covered with a Tungsten coating with a Molybdenum interlayer (W/Mo/CFC).However, due to the aging of the W/Mo/CFC coating, the APL have been redesigned and future antenna limiters will be made of copper alloy (CuCrZr) heat sink structure with a thick boron (B) coating to reduce remaining W impurity levels during plasma operations and address the blistering issues seen in previous coatings.Among all the techniques able to realise B coating, Plasma Spray is the most appropriate technique owing to its simplicity, low cost and ability to deposit thick boron coatings on complex geometries.Various boron coatings with thicknesses up to 900 µm were produced, characterized and their thermal behavior have been assessed using a specific laser heating program and a conventional electron/ion beam facility. This paper provides an overview of the R&D activities on boron coating developments and the related validation programs showing that the thermal conductivity of deposited films is drastically reduced compared to bulk boron, preventing use without additional coating optimization

Implant cochléaire et développement des échanges conversationnels.

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Le burn-out est-il une entité nosographique distincte ?

International audienceBien qu’il ait fait l’objet de nombreuses études depuis les années 1970, il n’y a pas de définition consensuelle ni de critères diag- nostiques clairs du burn-out. La conséquence en est souvent la non-reconnaissance du burn-out et de la souffrance des individus concernés. L’objectif de cette revue de la littérature est d’étudier si le burn-out devrait être considéré comme une catégorie diagnos- tique distincte. Malgré le fait que le burn-out soit un phénomène global, aucune revue récente n’a combiné les points de vue de différentes disciplines. Dans cette revue, nous avons recensé les arguments cliniques, psychologiques et biologiques de la recon- naissance du burn-out et nous les avons situés dans leurs contextes sociaux, politiques et économiques afin de dresser une image glo- bale de la thématique. Les futures recherches gagneraient à mettre fin au manque de consensus quant à la définition du burn-out, ses caractéristiques cliniques et ses outils d’évaluation

The response of anguilliform fish to underwater sound under an experimental setting

Traditional physical screens designed to prevent fish entering dangerous areas (e.g. turbine intakes) can have negative impacts due to impingement or mechanical abrasion at high velocities. Behavioural deterrents may provide an alternative approach to screening. This study investigated the potential for a continuous broadband sound to modify the behaviour of two endangered species of anguilliform fish, European eel (Anguilla anguilla) and river lamprey (Lampetra fluviatilis). Experiments were conducted in an experimental channel. Eel and lamprey were respectively released upstream and downstream of an “acoustic maze”. A single individual released per trial encountered two successive chambers that offered a choice of passage through either an ensonified or a control (ambient noise only) corridor with a speaker turned off. Two possible configurations were tested to control for any lateral bias with positions of the activated speakers reversed. The influence of treatment, chamber, and configuration on route selection, rejection, and time to pass were tested. No influence of any of the three factors on route selection was observed for eel. River lamprey tended to pass through the ensonified corridor more often under configuration 2, but only in the first chamber. Both species were more likely to reject the ensonified corridors than the controls, and the time taken to pass these routes was greater for those that did so. For eel, the variation in time to pass was greater for the non-migratory (yellow phase) life-stage. While the acoustic signal used in this study influenced fish behaviour, the response observed would likely be insufficient to induce a strong deterrent effect in the field if used in isolation