Les élèves étrangers ou issus de l'immigration dans l'école et le collège français. Une étude d'ensemble

Tous les enfants nés le 5 d'un mois et qui sont entrés au collège en septembre 1989 font l'objet, depuis cette date, d'une observation régulière conduite par la Direction de l'Evaluation et de la Prospective du Ministère de l'Education nationale. Au nombre de 20 000 environ, ils constituent le panel national 1989 d'élèves du second degré. Depuis leur fréquentation de l'école maternelle jusqu'à leur situation actuelle, le déroulement de leur parcours scolaire est connu avec précision. Une telle enquête statistique n'aurait pas été possible sans la collaboration active des chefs d'établissement, des enseignants et du personnel administratif des établissements scolaires, mais aussi des familles des élèves qui ont été interrogées au printemps 1991. Un certain nombre de ces élèves sont étrangers ou issus de l'immigration, que l'on approche cette population par le critère de nationalité, celui du lieu de naissance, le nombre d'années scolaires hors de France, l'ancienneté en France des parents ou la langue parlée à la maison. Le panel national permet une comparaison approfondie de leurs parcours scolaires à ceux de leurs condisciples. A quoi tiennent les redoublements plus fréquents qu'ont connus les enfants étrangers ou issus de l'immigration à l'école élémentaire ? A l'entrée en sixième, quelle est l'ampleur des écarts de performance en français et mathématiques entre ces élèves et leurs condisciples ? Comment s'explique la surreprésentation des enfants étrangers ou issus de l'immigration dans les sections d'éducation spécialisée ? Quel a été leur cheminement dans le collège français ? Sur tous ces aspects, l'analyse du panel national livre nombre de résultats inédits. Sait-on par exemple que les familles immigrées aspirent davantage que les autres familles de même condition sociale à ce que leur enfant poursuive de longues études ? S'il permet de mieux connaître la situation des enfants étrangers ou issus de l'immigration dans l'école et le collège de la France d'aujourd'hui, cet ouvrage livre aussi une analyse plus générale des inégalités de réussite scolaire entre élèves en fonction de leur environnement familial

Vers un jeu sérieux pour enseigner la programmation

International audienceLes jeux vidéo font partie intégrante de la culture au même titre que la télévision, les films et les livres. Nous pensons que ces applications de réalité virtuelle, grandement utilisées, peuvent servir à la formation des étudiants. Ce type d’outil est appelé : jeux sérieux. Les jeux sérieux sont présents, aujourd’hui, dans de nombreux secteurs d’activité comme l’éducation, la santé, la défense, l’industrie, la sécurité civile et les sciences. Ce document présente une étude pour déterminer le type de jeu le plus adapté à l’enseignement de la programmation. Les jeux de stratégie temps réel semblent êtreparticulièrement intéressants dans ce cadre

Nitrate and phosphorous evolution in surface water and groundwater across space and time scales – the example of the Jura Mountains

International audienceThe aim of this study is to explore the changes in water quality from local to large spatial scale and from short to long term periods, in order to better understand the fate and transport of pollutants. Our work focused on the analysis of nutrients in surface and groundwaters in the karstic catchment of the Loue river (~ 1000 km²) in the French Jura Mountains. The hydrological behavior of this large basin is highly controlled by surface water-groundwater interactions. Recurrent algae proliferation and a scarcity of species considered to be sensitive are indices of a chronic degradation of the water quality.A first analysis of long term evolution of nitrate over 45 yrs in surface water shows that the nitrate concentration in waters (mean value of 10 mg/l) is controlled mainly by a seasonal effect (from 2 to 40 mg/l). A long term component is also observed showing an increase of several mg/l from 70's to 90's and then a decrease from 2000 to present. This long-term evolution is correlated to the annual amount of synthetic fertilizers used in cultivated areas of the Jura Mountains. On the contrary to nitrate, phosphorous evolution shows no long-term trend. Changes are mostly controlled by several peaks often superior to 0.2 mg/l, and occurring more frequently during autumn.A second analysis of short-term evolution was carried out at the seasonal and event-time scales comparing concentrations and fluxes at 5 gauging stations over the catchment. This analysis showed contrasted nitrate and phosphorous evolutions depending the location. High level nitrate concentrations occurred after recharge events in autumn and winter. The nitrate decrease during spring and summer reaches in some locations the detection limit. This pattern is attributed to the biomass productivity during hottest and driest months. Regarding phosphorous evolution, erratic peaks occurred after rainfalls without their amplitude being correlated with that one of the rainfalls, meaning that it originated probably from effluents from wastewater treatment plants.Finally, these first results showed the spatial and temporal variability of water contamination by nutrients, highlighting the complex hydrological and ecological behaviour on the various sub-catchments. The spatio-temporal variability of anthropogenic activities associated with the complexity of transport processes and with the hydrological conditions are the key processes that explain these contrasting responses within the same hydrosystem

La qualité des relations sociales au sein des SCOP : premiers enseignements d'une enquête en Rhône-Alpes

Ce travail de recherche a été mené depuis le printemps 2012 jusqu'à l'automne 2013 et nous a amenés à enquêter auprès de 40 SCOP. Dans la première partie de ce rapport, nous présentons les éléments saillants de nos observations qui sont ressortis comme récurrents dans un grand nombre de cas. Nous en tirons un constat résumé par le titre de "la qualité des relations humaines au sein des SCOP" pour pointer des caractéristiques communes présentées en trois chapitres qui portent sur : - les indicateurs favorables de qualité de l'emploi ; - des collectifs participatifs et cohésifs ; - des organisations introspectives et adaptatives. En outre, la diversité est extrême à l'intérieur du monde des SCOP. Ce sera l'objet de la seconde partie de ce rapport où nous tenterons de développer des analyses pertinentes des différences entre les SCOP qui ressortent de notre enquête. C'est à travers trois chapitres que nous avancerons ces propositions d'analyse en nous fondant sur : - les diverses données recueillies sur les SCOP ; - les résultats des questionnaires adressés aux salariés ; - un essai de typologie des SCOP en 7 catégories

A three-level signature by graph for Reverse Engineering of mechanical assemblies

Several approaches exist to provide Reverse Engineering solutions on mechanical parts. Mechanical assemblies and the expertise information retrieved at the same time with the model geometry are not really taken into account in the literature. Thus, the main challenge of this contribution is to propose a methodology to retrieve the Digital Mock-Up of a mechanical assembly from its meshed data (from digitalization). The output DMU consists of expertise information and parameterized CAD models. The methodology proposed relies on a signature by a three-level graph. It enables to provide an adequate level of details by identifying the corresponding functional surfaces in meshed data. The first-level graph is a connectivity graph; the intermediate level is the same as the first with the geometric type of face added to each node (plane, cylinder and sphere) and the deepest level corresponds to a precedence graph. This one provides information such as functional surfaces and position between them (perpendicularity, coaxiality etc.). The solutions developed and the results are presented in this paper. The methodology is illustrated thanks to an industrial use-case with a scan of an assembly with a connecting rod and a piston. The conclusion and perspectives will complete this paper

The spalling decay of building bioclastic limestones of Provence (South East of France): From clay minerals swelling to hydric dilation

International audienceMedieval historical monuments of the Provence region (South East of France) were erected with bioclastic limestones and display different sensitivities to spalling decay. The present study aims at understanding the physical processes at play as well as the internal properties governing its intensity. Limestones of contrasting sensitivity to spalling were compared to a reference type, unaffected by this decay, by means of petrography, petrophysic, mineralogy, and hydromechanics. The obtained results highlighted that the various sensitivities can be explained by the deformation recorded during water content variation (hydric dilation). A clay fraction was systematically detected within the mineralogical composition except for the reference material, and some swelling layers were identified in ontmorillonite/glauconite mixed layer minerals. A specific quantification procedure based on the combination of transmission electron microscopy coupled to an energy-dispersive X-ray spectrometer (TEM–EDX) and profile modeling of X-ray diffraction patterns was applied. A strong relationship between swelling layer content and hydric dilation of limestones was evidenced and corroborated the spalling sensitivity. Further interpretation of results showed that swelling layers localization within the texture significantly influence hydric dilation kinetics. Eventually, a mechanical softening was measured after water saturation. This behavior seems unrelated to the clay mineral content and its relative influence on spalling should be examined

Central venous O2 saturation and venous-to-arterial CO2 difference as complementary tools for goal-directed therapy during high-risk surgery

International audienceIntroduction: Central venous oxygen saturation (ScvO 2) is a useful therapeutic target in septic shock and high-risk surgery. We tested the hypothesis that central venous-to-arterial carbon dioxide difference (P(cv-a)CO 2), a global index of tissue perfusion, could be used as a complementary tool to ScvO 2 for goal-directed fluid therapy (GDT) to identify persistent low flow after optimization of preload has been achieved by fluid loading during high-risk surgery. Methods: This is a secondary analysis of results obtained in a study involving 70 adult patients (ASA I to III), undergoing major abdominal surgery, and treated with an individualized goal-directed fluid replacement therapy. All patients were managed to maintain a respiratory variation in peak aortic flow velocity below 13%. Cardiac index (CI), oxygen delivery index (DO 2 i), ScvO 2 , P(cv-a)CO 2 and postoperative complications were recorded blindly for all patients. Results: A total of 34% of patients developed postoperative complications. At baseline, there was no difference in demographic or haemodynamic variables between patients who developed complications and those who did not. In patients with complications, during surgery, both mean ScvO 2 (78 ± 4 versus 81 ± 4%, P = 0.017) and minimal ScvO 2 (minScvO 2) (67 ± 6 versus 72 ± 6%, P = 0.0017) were lower than in patients without complications, despite perfusion of similar volumes of fluids and comparable CI and DO 2 i values. The optimal ScvO 2 cutoff value was 70.6% and minScvO 2 < 70% was independently associated with the development of postoperative complications (OR = 4.2 (95% CI: 1.1 to 14.4), P = 0.025). P(cv-a)CO 2 was larger in patients with complications (7.8 ± 2 versus 5.6 ± 2 mmHg, P < 10-6). In patients with complications and ScvO 2 ≥71%, P(cv-a)CO 2 was also significantly larger (7.7 ± 2 versus 5.5 ± 2 mmHg, P < 10-6) than in patients without complications. The area under the receiver operating characteristic (ROC) curve was 0.785 (95% CI: 0.74 to 0.83) for discrimination of patients with ScvO 2 ≥71% who did and did not develop complications, with 5 mmHg as the most predictive threshold value

Thermal Reconversion of Oxidised Lead White in Mural Paintings via a Massicot Intermediate

Lead white is the most ancient and common white pigment used in mural paintings. However, it tends to blacken with time due to its oxidation to plattnerite (\b{eta}-PbO2). Chemical treatments were used but they can put the pictorial layers supports at risks. Hereby we address the possibility of thermally reconverting black plattnerite to white lead carbonates via a massicot (\b{eta}-PbO) intermediate, with a view to developing a restoration procedure using continuous wave laser heating. We first investigated the conditions (temperature, time, and environment) in which pure powders react, before studying mural painting samples. Experiments were made in ovens and TGA and XRD and SEM characterization were achieved. Litharge ({\alpha}-PbO) and massicot were obtained from plattnerite respectively between 564 and 567 {\deg}C and at 650 {\deg}C. Lead carbonates (cerussite, hydrocerussite and plumbonacrite) formed from massicot in wet CO2 below 100 {\deg}C in a few hours. Lastly, when heating plattnerite based mural painting samples, lead species reacted with binders and mortar, yielding massicot, plumbonacrite but also lead silicate and calcium lead oxides. This demonstrates the viability of thermal reconversion of darkened lead in mural, while raising concerns about the formation of several lead species by reaction with mural painting constituents