Combining multigrid and wavelet ideas to construct more efficient multiscale algorithms for the solution of Poisson's equation

International audienceIt is shown how various ideas that are well established for the solution of Poisson's equation using plane wave and multigrid methods, can be combined with wavelet concepts. The combination of wavelet concepts and multigrid techniques turns out to be particularly fruitful. We propose a modified multigrid V cycle scheme that is not only much simpler, but also more efficient than the standard V cycle. Whereas in the traditional V cycle the residue is passed to the coarser grid levels, this new scheme does not require the calculation of a residue. Instead it works with copies of the charge density on the different grid levels that were obtained from the underlying charge density on the finest grid by wavelet transformations. This scheme is not limited to the pure wavelet setting, where it is faster than the preconditioned conjugate gradient method, but equally well applicable for finite difference discretizations

PIANO Reference Manual Python Interface for Assimilation in NemO

PIANO Reference Manual: Python Interface for Assimilation in Nem

Chapter Cheminer dans les espaces pastoraux du Buccolicum carmen avec Boccace

The present article aims to present Boccaccio’s Buccolicum carmen as a main work in his latin production, inspired by Vergil and his followers during the Middle Age. Through the allegorical path, focused on the shepherd’s environment, Boccaccio first defines a model of power embodied by the king-shepherd. Moreover, he tries to convert his readers, as well as himself, into a better way of life related to Vergil’s one and close to the eremitic model. By doing so, he accomplishes himself as a poeta-theologus, as exposed by Dante

Les émotions au service de la métamorphose identitaire des professeurs stagiaires d’anglais de l’académie de Créteil

L’année de formation initiale des enseignants stagiaires est riche en émotions (Lemarchand-Chauvin & Tardieu, 2018) et leur position transitoire entre deux temps, à moitié étudiant et à moitié enseignant, la rend parfois douloureuse et difficile. Durant cette période de transition – qui n’est pas sans rappeler la crise identitaire de l’adolescent – le stagiaire va progressivement enclencher la construction de son identité professionnelle. Cette étude s’appuie sur deux cohortes de professeurs stagiaires d’anglais de l’académie de Créteil. Elle repose sur l’hypothèse qu’il est possible d’accompagner les professeurs stagiaires dans leur métamorphose en leur permettant de partager leurs émotions (Rimé, 2005) avec leurs pairs par le biais de groupes de parole libre favorisant l’écoute empathique, de modules engageant le corps et la voix (Pujade-Renaud, 1984 ; Tellier & Cadet, 2014) et des sessions de théâtre forum. Placer les émotions et l’empathie au cœur de la formation initiale permettrait d’accéder plus facilement à la réflexivité (Schön, 1983, 1987) et à la croissance professionnelle ou métamorphose des enseignants débutants.Pre-service teachers undergo many emotional episodes (LeMarchand-Chauvin & Tardieu, 2018) during the year of their initial training, and their “in-between” position – half-student and half-teacher – can make it even more painful and difficult to cope with. During this transitional period, which could be compared to adolescence, pre-service teachers’ professional identity is gradually going to develop and emerge. This research was conducted with two cohorts of pre-service English teachers from the academy of Créteil (France). It is based on the hypothesis that their metamorphosis process could be sustained through the sharing their emotions (Rimé, 2005) with their peers in support groups, sessions of analysis of professional practice (Clos, 1999; Etienne & Fumat, 2014) based on empathic listening, and through body and voice expression workshops (Pujade-Renaud, 1984; Tellier & Cadet, 2014). Setting emotions and empathy at the core of pre-service teachers’ training could give novice teachers access to reflectivity (Schön, 1983, 1987), to professional growth or metamorphosis

Why underserved patients do not consult their general practitioner for depression: results of a qualitative and a quantitative survey at a free outpatient clinic in Paris, France

International audienceBackground : The prevalence of depression in the general population is 5 to 10% but can exceed 50% in the most socially vulnerable populations. The perceptions of this disease are widely described in the literature, but no research has been carried out in France to explain the reasons for not consulting a general practitioner during a depressive episode, particularly in people in the most precarious situations. The objective of this study was to describe the reasons for not seeking primary care during a depressive episode in a socially vulnerable population.Methods : An exploratory sequential design with a preliminary qualitative study using a phenomenological approach. Subsequently, themes that emerged from the qualitative analysis were used in a questionnaire administered in a cross-sectional observational study at a free outpatient clinic in Paris in 2010. Lastly, a logistic regression analysis was performed.Results : The qualitative analysis revealed four aspects that explain the non-consulting of a general practitioner during a depressive episode: the negative perception of treatment, the negative perception of the disease, the importance of the social environment, and the doctor-patient relationship. The quantitative analysis showed that close to 60% of the patients who visited the free clinic were depressed and that only half of them had talked with a care provider. The results of the statistical analysis are in line with those of the qualitative analysis, since the most common reasons for not seeing a general practitioner were the negative perception of the disease (especially among the men and foreigners) and its treatments (more often among the men and French nationals).Conclusions : Close to 50% of the depressed individuals did not seek primary care during a depressive episode, and close to 80% of them would have liked their mental health to be discussed more often by a health professional. Better information on depression and its treatments, and more-systematic screening by primary care personnel would improve the treatment of depressed patients, especially those in the most precarious situations

Stochastic Downscaling Method: Application to Wind Refinement

International audienceIn this article, we propose a new stochastic downscaling method: provided a numerical prediction of wind at large scale, we aim to improve the approximation at small scales thanks to a local stochastic model. We first recall the framework of a Lagrangian stochastic model borrowed from S.B. Pope. Then, we adapt it to our meteorological framework, both from the theoretical and numerical viewpoints. Finally, we present some promising numerical results corresponding to the simulation of wind over the Mediterranean Sea

Convergence properties and numerical simulation by an adaptive FEM of the thermistor problem

In this paper, the convergence properties of the finite element approximation of the thermistor problem are investigated, both from theoretical and numerical point of view. From one hand, based on a duality argument, a theoretical convergence result is proved under low regularity assumption. From other hand, numerical experiments are performed based on a decoupled algorithm. Moreover, on a non convex domain, the convergence properties versus the mesh size are shown to be improved by using suitable mesh adaptation strategy and error estimator

Assimilation of Lagrangian Data Documentation of the observation operator. Demonstrator for the twin experiments

In the framework of the Argo program, profiling drifting floats are now routinely launched in the world's oceans. These floats provide (among other information) data about their position, sampled every ten days, representative of their Lagrangian drift. Previous works have shown the interest of assimilating this new type of data. The assimilation of Lagrangian-type data such as position of drifting floats is not straightforward; it involves the careful implementation of a complex, non-linear observation operator but it is of importance for an application in operational oceanography. For instance this work is useful for localized experiments with surface-drifting floats: the information provided by the Lagrangian data could help to improve any operational system aiming to forecast currents for various applications with significant societal impact, such as coastal rescue or pollutant spreading. The sequence of images (pictures from satellite) provides another important source of Lagrangian data: indeed, it describes the displacement of Lagrangian structures (vortex, fronts ...). Finally, this work could provide guidance for the design of the observational network (distribution of large-scale Argo floats / number of localized surface floats / drifting depth, and so on)

Natural Transmission of Zoonotic Babesia spp. by Ixodes ricinus Ticks

To determine characteristics of natural transmission of Babesia sp. EU1 and B. divergens by adult Ixodes ricinus ticks, we examined tick salivary gland contents. We found that I. ricinus is a competent vector for EU1 and that their sporozoites directly invade erythrocytes. We conclude that EU1 is naturally transmitted by I. ricinus