1,793 research outputs found
Experimental results on mass-thickness distribution in spacecraft equipment
A technique is described for evaluating the shielding properties of spacecraft equipment with respect to cosmic radiation. A gamma-ray source is used in conjunction with a scintillation detector to determine mass-thickness distribution both in plane geometry for equipment units, and in spherical geometry for given points within the spacecraft. Equations are presented for calculating mass-thickness distribution functions, and the results are compared with experimental measurements
Forms of work organization and associations with shoulder disorders: Results from a French working population
The aim of this study was to identify forms of work organization in a French region and to study associations with the occurrence of symptomatic and clinically diagnosed shoulder disorders in workers. Workers were randomly included in this cross-sectional study from 2002 to 2005. Sixteen organizational variables were assessed by a self-administered questionnaire: i.e. shift work, job rotation, repetitiveness of tasks, paced work/automatic rate, work pace dependent on quantified targets, permanent controls or surveillance, colleagues\u27 work and customer demand, and eight variables measuring decision latitude. Five forms of work organization were identified using hierarchical cluster analysis (HCA) of variables and HCA of workers: low decision latitude with pace constraints, medium decision latitude with pace constraints, low decision latitude with low pace constraints, high decision latitude with pace constraints and high decision latitude with low pace constraints. There were significant associations between forms of work organization and symptomatic and clinically-diagnosed shoulder disorders
CrĂ©ation dâun score dâĂ©valuation du risque de symptĂŽmes musculo-squelettiques basĂ© sur des facteurs professionnels
Objectif
Lâobjectif de ce travail est la crĂ©ation dâun score dâĂ©valuation du risque de symptĂŽmes musculo-squelettiques (SMS) chroniques des membres supĂ©rieurs, uniquement basĂ© sur des donnĂ©es dâexposition professionnelle aux dĂ©terminants biomĂ©caniques, psychosociaux et organisationnels. Ce score ne prenant pas en compte les facteurs individuels, permettra de classer les situations de travail devant bĂ©nĂ©ficier dâune action de prĂ©vention.
MĂ©thodes
LâĂ©chantillon dâĂ©tude Ă©tait constituĂ© de 1749 salariĂ©s recrutĂ©s lors de la phase dâinclusion de la cohorte des salariĂ©s ligĂ©riens (COSALI). Les facteurs organisationnels, biomĂ©caniques et psychosociaux et les variables associĂ©es aux SMS chroniques ont Ă©tĂ© recueillis par auto-questionnaire. Un score a Ă©tĂ© crĂ©Ă© selon trois mĂ©thodes statistiques : une rĂ©gression logistique binaire, une analyse en clusters suivie dâune analyse par arbre de dĂ©cision et une modĂ©lisation par classes latentes. Chacune de ces mĂ©thodes est susceptible dâentraĂźner la crĂ©ation de scores diffĂ©rents.
RĂ©sultats
Lâarea under the curve (AUC) obtenu par la rĂ©gression logistique Ă©tait de 0,75 contre 0,66 pour lâanalyse en clusters et 0,65 pour lâanalyse en classes latentes. La rĂ©gression logistique a donc Ă©tĂ© retenue pour la crĂ©ation du score. Les facteurs associĂ©s aux SMS chroniques des membres supĂ©rieurs Ă©taient lâintensitĂ© Ă©levĂ©e des efforts physiques ressentie (Ă©chelle RPE de Borg), la rĂ©pĂ©titivitĂ© des gestes plus de 4 h/j, la flexion du coude plus de 2 h/j, lâutilisation de la pince pouce-index plus de 4 h/j, la possibilitĂ© dâinfluencer le dĂ©roulement de son travail et lâaide des collĂšgues. Le score a ensuite Ă©tĂ© crĂ©Ă© Ă partir des paramĂštres estimĂ©s de la rĂ©gression logistique, il sâĂ©tend de â1 à 15. Par exemple, 66 % de lâĂ©chantillon a un score supĂ©rieur ou Ă©gal Ă deux. Pour ce seuil, la valeur prĂ©dictive nĂ©gative est de 93,4 %.
Conclusions
Selon le seuil choisi, le score aboutit Ă une forte valeur prĂ©dictive nĂ©gative. Il pourrait constituer un outil utile aux prĂ©venteurs en entreprise afin de cibler lâeffectif pour lequel il nâest pas indispensable de mettre en place des actions de prĂ©vention. NĂ©anmoins ce score ne permet pas de prĂ©dire avec confiance les salariĂ©s qui seront atteints de SMS. Pour avoir un score plus performant, il faudrait intĂ©grer des facteurs individuels tels que lâĂąge et le sexe, mais la caractĂ©risation par situation de travail nâest alors plus envisageable
Evidence for Electron Energization Accompanying Spontaneous Formation of Ion Acceleration Regions in Expanding Plasmas
We report experiments conducted in an expanding argon plasma generated in the inductive mode of a helicon source in the Hot hELIcon eXperimentâLarge Experiment on Instabilities and Anisotropies facility. As the neutral gas pressure increases, the supersonic ion acceleration weakens. Increasing neutral pressure also alters the radial profile of electron temperature, density, and plasma potential upstream of the plasma expansion region. Langmuir probe measurements of the electron energy probability function (EEPF) show that heating of electrons at the plasma edge by RF fields diminishes with increasing gas pressure, yielding a plasma with a centrally peaked electron temperature, and flat potential profiles at higher neutral pressures. For neutral pressures at which ion acceleration regions develop in the expanding plasma plume, EEPFs reveal electrons with two temperature components
Les troubles de la communication du patient cĂ©rĂ©brolĂ©sĂ© droit : intĂ©rĂȘts du groupe de rĂ©Ă©ducation pluridisciplinaire sâinspirant du thĂ©Ăątre dâimprovisation
Evolution of psychosocial factors at work in a French region
Background : Psychosocial factors at work (PFW) can be defined as all non-physicochemical occupational risks. Several epidemiological models have been proposed to measure PFW, but one of the most widely used is Karasekâs model.
Aims : To determine whether psychosocial factors, evaluated by Karasekâs questionnaire, had increased in a cohort of workers.
Methods : A random sample of workers in the Pays de la Loire region of France, who could be considered representative of the regionâs population of salaried workers, filled in a self-administered questionnaire, including Karasekâs self-administered questionnaire, in 2002â05 and 2007â09. Karasekâs questionnaire can be used to study three psychosocial dimensions (psychological demand, decision latitude and social support in the workplace) in workers in order to define two high-risk situations for their health: âJob Strainâ and âIso Strainâ. Changes in job strain and iso strain among workers were studied according to the workersâ sociodemographic characteristics and their working conditions.
Results : In this sample of 2049 workers, the proportion with iso strain increased between the two periods from 12 to 16%, P < 0.001, mainly among manual workers. Deterioration of Karasek indicators was mainly explained by an increase of the âlow social supportâ dimension (38 versus 49%, P < 0.001). Working conditions such as temporary employment of colleagues and high perceived physical exertion were associated with higher PFW.
Conclusions : This study, based on a quantitative and collective model, showed deterioration of working team environments and increased risk for individual mental health in this cohort of French workers in recent years
apeNEXT: A multi-TFlops Computer for Simulations in Lattice Gauge Theory
We present the APE (Array Processor Experiment) project for the development
of dedicated parallel computers for numerical simulations in lattice gauge
theories. While APEmille is a production machine in today's physics simulations
at various sites in Europe, a new machine, apeNEXT, is currently being
developed to provide multi-Tflops computing performance. Like previous APE
machines, the new supercomputer is largely custom designed and specifically
optimized for simulations of Lattice QCD.Comment: Poster at the XXIII Physics in Collisions Conference (PIC03),
Zeuthen, Germany, June 2003, 3 pages, Latex. PSN FRAP15. Replaced for adding
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