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Faire un état des lieux de la fréquence des principales complications de la grossesse chez le personnel du CHU de Bordeaux et les comparer aux données de la population générale (enquête périnatale).

Les photocopieurs sont considérés comme des outils essentiels dans les entreprises. De plus en plus de salariés se plaignent auprès de leur service de santé au travail de symptômes qu’ils attribuent à leur exposition au photocopieur. Il s’agit donc de connaître les risques liés à cette exposition. Le fonctionnement d’un photocopieur est basé sur l’électrophotographie, c’est-à-dire le transfert électrostatique de la poudre de toner vers une surface photoconductrice chargée électriquement. Lors du processus d’impression, des poussières de toner, des composés organiques volatils, des gaz comme l’ozone, des particules ultrafines sont émis. Les émissions sont variées et variables suivant le type et le mode de fonctionnement du photocopieur. Les niveaux d’exposition sont mal connus mais se situent sous les valeurs limites d’exposition en vigueur lors des différentes études. Les études animales permettent de démontrer qu’il faut des niveaux d’exposition importants pour développer une pathologie respiratoire. Aucune étude n’est en mesure de certifier la relation entre l’exposition aux photocopieurs et les pathologies respiratoires chroniques et cancéreuses. Des études supplémentaires doivent donc être menées. Enfin, il n’existe à ce jour aucune réglementation et recommandation spécifiques sur l’utilisation des photocopieurs.

The initial–boundary value problem for a general balance law in a bounded domain is proved to be well posed. Indeed, we show the existence of an entropy solution, its uniqueness and its Lipschitz continuity as a function of time, of the initial datum and of the boundary datum. The proof follows the general lines in [4], striving to provide a rigorous treatment and detailed references.

We study a rather general class of 1D nonlocal conservation laws from a numerical point of view. First, following [F. Betancourt, R. Bürger, K.H. Karlsen and E.M. Tory, On nonlocal conservation laws modelling sedimentation. Nonlinearity 24 (2011) 855–885], we define an algorithm to numerically integrate them and prove its convergence. Then, we use this algorithm to investigate various analytical properties, obtaining evidence that usual properties of standard conservation laws fail in the nonlocal setting. Moreover, on the basis of our numerical integrations, we are led to conjecture the convergence of the nonlocal equation to the local ones, although no analytical results are, to our knowledge, available in this context.

Notre objectif est de décrire les effets respiratoires d’une exposition chronique et subaiguë à l’hydrogène sulfuré (H2S).

This paper develops the basic analytical theory related to some recently introduced crowd dynamics models. Where well posedness was known only locally in time, it is here extended to all of ℝ+. The results on the stability with respect to the equations are improved. Moreover, here the case of several populations is considered, obtaining the well posedness of systems of multi-D non-local conservation laws. The basic analytical tools are provided by the classical Kružkov theory of scalar conservation laws in several space dimensions.

Several realistic situations in vehicular traffic that give rise to queues can be modeled through conservation laws with boundary and unilateral constraints on the flux. This paper provides a rigorous analytical framework for these descriptions, comprising stability with respect to the initial data, to the boundary inflow and to the constraint. We present a framework to rigorously state optimal management problems and prove the existence of the corresponding optimal controls. Specific cases are dealt with in detail through ad hocnumerical integrations. These are here obtained implementing the wave front tracking algorithm, which appears to be very precise in computing, for instance, the exit times.

Motivated by a traffic model, we study a conservation law whose solutions naturally need to be bounded Radon measures. We investigate the relations between this equation and finite systems of conservation laws that converge to it.

We present a model for the flow of pedestrians that describes features typical of this flow, such as the fall due to panic in the outflow of people through a door. The mathematical techniques essentially depend on the use of non‐classical shocks in scalar conservation laws. Copyright © 2005 John Wiley & Sons, Ltd.

This paper contains several recent results about nonlinear systems of hyperbolic conservation laws obtained through the technique of Wave Front Tracking.

Consider an n×nsystem of hyperbolic balance laws with coinciding shock and rarefaction curves. This note proves the well-posedness in the large of this system, provided there exists a domain that is invariant both with respect to the homogeneous conservation law and to the ordinary differential system generated by the right-hand side. No "non-resonance" hypothesis is assumed.

Consider an n×n system of hyperbolic balance laws with coinciding shock and rarefaction curves. This note proves the well-posedness in the large of this system, provided there exists a domain that is invariant both with respect to the homogeneous conservation law and to the ordinary differential system generated by the right-hand side. No "non-resonance" hypothesis is assumed.

We consider an n × n system of hyperbolic conservation laws and focus on the case of strongly underdetermined sonic phase boundaries. We propose a Riemann solver that singles out solutions uniquely. This Riemann solver has two features: it selects phase boundaries by means of an exterior function and it allows compound waves. Then we prove the global existence of weak solutions to the Cauchy problem. Applications to Chapman–Jouguet deflagrations are given. Copyright © 2004 John Wiley & Sons, Ltd.

We consider an n × n system of hyperbolic conservation laws and focus on the case of strongly underdetermined sonic phase boundaries. We propose a Riemann solver that singles out solutions uniquely. This Riemann solver has two features: it selects phase boundaries by means of an exterior function and it allows compound waves. Then we prove the global existence of weak solutions to the Cauchy problem. Applications to Chapman–Jouguet deflagrations are given. Copyright © 2004 John Wiley & Sons, Ltd.

We present an $n$-population generalization of the Lighthill–Whitham and Richards traffic flow model. This model is analytically interesting because of several non-standard features. For instance, it leads to non-classical shocks and enjoys an unexpected stability in spite of the presence of umbilic points. Furthermore, while satisfying all the minimal ‘common sense’ requirements, it also allows for a description of phenomena often neglected by other models, such as overtaking.

We deal with a strictly hyperbolic system of two conservation laws in one spatial dimension. One of the eigenvalues of the system is of Temple type (rarefaction and shock curves coincide), the other eigenvalue is only required to be genuinely nonlinear.We consider the initial value problem for data of the following kind: the total variation of the Temple component is bounded, possibly large, while the total variation of the other component is small. For such data we prove global existence, uniqueness and L¹-Lipschitz continuous dependence of solutions.

Postoperative infectious complications after breast surgery may result in significant morbidity, psychological trauma, and additional costs. We assessed the efficacy of preoperative antibiotic prophylaxis for surgery in a randomized, double-blind trial of 1,766 patients undergoing breast surgery. From January 1, 1996 to August 31, 1997, all eligible patients were assigned randomly to receive a single dose of ceftriaxone (2 g) or ceftazidime (2 g) given intravenously at the induction of anesthesia, with no further doses. The groups were similar with respect to age, operative procedure, operative time and time to discharge after operation. The patients who received ceftriaxone prophylaxis had 54.4% fewer overall infections than those who received ceftazidime prophylaxis. Wound infection occurred in 0.45% of the ceftriaxone recipients (2 of 883) and 0.91% of the ceftazidime recipients (8 of 883). This prospective randomized double-blind study showed that the long-acting regimen containing ceftriaxone is more cost-effective than the short-acting ceftazidime in preventing postoperative infections in patients subjected to breast surgery.

The main result of this paper is the construction of the Standard Riemann Semigroup for a class of 2 × 2 Conservation Laws without ther equirement that the total variation of the initial data be small. For a class of equations of the form it is shown that there exists an L1-Lipchitz continuous semigroup S defined on functions of bounded variation, such that the trajectories of S are weak entropy solutions to (*). This class includes the relativistic Euler equations.

Consider the Cauchy problem for a strictly hyperbolic 2×2 system of conservation laws in one space dimension: {ie1-01} assuming that each characteristic field is either linearly degenerate or genuinely nonlinear. This paper develops a new algorithm, based on wave-front tracking, which yields a Cauchy sequence of approximate solutions, converging to a unique limit depending continuously on the initial data. The solutions that we obtain constitute a semigroup S, defined on a set {ie1-02} of integrable functions with small total variation. For some Lipschitz constant L, we have the estimate {ie1-03}

A simple and stereospecific synthesis of the triketolactam 15is described. This compound has been previously converted to napelline 1. The key step of the synthesis is the rearrangement of the "denudatine" intermediate 11to the napelline derivative 12. The denudatine skeleton was constructed by a stereospecific diene addition belween the o-quinone acetal 4and benzyl vinyl ether. It is expected that this last process will be capable of general application in the synthesis of complex compounds.

En Suisse, la thématique des risques psychosociaux est en essor. Trente-quatre pour cent des salariés se disent stressés avec des répercussions sur leur santé. Mise en place en 2009 à l’IST, la consultation travail et souffrance vise à faire émerger les déterminants du processus de déstabilisation, dans une perspective d’élargissement des scénarios de lecture, d’optimisation des soins, d’aide à la décision et restauration de la capacité d’action. Pluridisciplinaire, collaborative, elle permet d’entrevoir la dynamique psychique du collaborateur, en particulier à travers son rapport au travail. L’objectif est de préciser ses besoins et apports.

Psychosocial suffering involves diverse human, social and economic costs. Some 34.4% of workers in Switzerland report chronic stress related to their jobs. Medical consultations for suffering at work aim to maintain—or renew—patients’ abilities to make decisions and act following a diagnosis of psychological suffering related to their work; they also aim to help workers return to their workstations or remain there. Workplace interventions by consulting occupational physicians can go beyond the subjective issues: they can be offered to employees, in anticipation of a return to work when this appears feasible from the outset.

Les études expérimentales ou épidémiologiques réalisées sur les expositions aux nanoparticules ou sur la pollution particulaire ultrafine indiquent que ces expositions peuvent induire des effets délétères sur la santé. Notre objectif est de synthétiser les données sur la biodistribution des nanoparticules inhalées et sur les méthodes utilisées dans les études toxicologiques qui pourraient être utilisées dans la surveillance des travailleurs exposés à ce type de particules.