Conception et diffusion de ressources en ligne pour gérer la diversité cognitive des élèves et favoriser leur réussite dans l'apprentissage de l'algèbre

54 pages (annexes en plus)Les projets Pépite, LINGOT et PépiMEP résultent d'une longue collaboration entre chercheurs en didactique des mathématiques, chercheurs en informatique, enseignants et formateurs. Ces projets visent d'une part à concevoir des outils à destination des enseignants pour gérer l'hétérogénéité des apprentissages des élèves en algèbre élémentaire en fin de scolarité obligatoire et, d'autre part, à en évaluer les usages réels en classe et leur influence sur l'activité des élèves en algèbre. Le projet PépiMEP a permis la diffusion, sur la plateforme en ligne LaboMEP de l'association Sésamath, accessible gratuitement à grande échelle, des résultats issus des premières recherches sur le diagnostic et l'enseignement adapté aux besoins repérés des élèves

CAMPAGNE DE MESURE POUR UNE ÉTUDE DE L'EXPOSITION DE LA POPULATION FRANÇAISE AU CHAMP MAGNÉTIQUE 50 HZ

Longtemps considérés comme inoffensifs, les champs magnétiques (CM) alternatifs de fréquence 50 Hz liés à l'électricité en particulier, sont suspectés depuis une trentaine d'années d'être responsables de pathologies, notamment de leucémies chez l'enfant. Les dernières expertises collectives [1] ont conclu que la dernière grande interrogation en ce qui concerne les CM basse fréquence est l'association statistique observée dans plusieurs analyses conjointes entre l'augmentation du risque de leucémie de l'enfant et une exposition aux CM supérieure à 0,4 μT en valeur moyenne sur 24 heures

Exposition de la population française aux champs magnétiques 50 Hz : résultats partiels

Les champs magnétiques (CM) alternatifs de fréquence 50 Hz, liés à l'électricité en particulier, sont suspectés depuis une trentaine d'années d'être responsables de pathologies, notamment de leucémies chez l'enfant [1]. Les dernières expertises collectives (OMS 2007, SCENHIR 2009) ont conclu que la dernière grande interrogation en ce qui concerne les CM basse fréquence est l'association statistique observée dans plusieurs analyses conjointes entre l'augmentation du risque de leucémie de l'enfant et une exposition aux CM supérieure à 0,4 μT en valeur moyenne sur 24 h [2]. Actuellement, l'exposition de la population française à ces champs n'est connue que de manière très approximative. Une étude effectuée dans le département de la Côte d'Or sur des logements situés à proximité de lignes à haute et très haute tension a permis d'évaluer les expositions à l'intérieur de ces logements [3]. Mais, d'une part il s'agit d'un faible échantillon compte tenu de la diversité du parc de logements en France, d'autre part, il s'agit d'une exposition du logement et non des personnes. En effet, tout un chacun est exposé à de nombreuses sources de champ magnétique du simple fait qu'on ne reste pas chez soi 24 heures sur 24. Les transports, en particulier, représentent des sources d'exposition significatives, mais d'autres lieux de vie peuvent constituer des sources d'exposition, que ce soit le lieu de travail, le terrain de sport, le centre commercial ou l'école. Dans le cas où le CM supérieur 0,4 μT en moyenne représenterait un risque pour la santé, comment estimer la proportion de la population française à risque et identifier les sources favorisant l'exposition ? Pour répondre à cette question, la Direction Générale de la Santé a initié une étude sur l'exposition aux CM 50 Hz d'un échantillon représentatif de la population française. Une des problématiques de cette étude a été de réaliser cet échantillon et de collecter toutes les informations nécessaires. Pour réaliser cette étude, le recrutement des volontaires et les mesures du CM ont été effectués en trois campagnes. Nous présentons les résultats des deux premières campagnes

French population exposure to 50 Hz magnetic fields : intermediate results

International audienceFor the last thirty years, the electricity related 50 Hz magnetic fields (MF) have been suspected of being responsible for several pathologies, in particular childhood leukemia [1]. The most recent collective expertise (WHO 2007 and SCENHIR 2009) concluded that the last major interrogation with regard to low frequency MF is the statistical association observed in several joint analyses between the increase of risk of the childhood leukemia and a higher than 0.4 μT exposure to MF on average in a 24-hour period [2]. Currently, the exposure of the French population to these magnetic fields is only approximately known. A study carried out in residences located near high voltage power lines in the "département1 de la Côte d'Or" made it possible to assess the MF background level inside these residences [3]. However, these residences are a limited sample compared to the diversity of the housing developments in France and the study characterized the exposure of the houses and not of the resident people. We are all exposed to many sources of magnetic fields due the fact that we do not remain at home 24 hours a day. Transportation in particular, significantly contributes to the individual exposure. Other places or activities can also constitute sources of exposure such as the workplace, sport activity areas, shopping centers or schools. Should the MF in excess to 0.4 μT on average carry health risk, would the authorities be able to manage it, i.e. estimate the proportion of the French population at risk and identify and mitigate the main sources causing the exposure? To answer this question the Ministry of Health and Solidarities initiated a study on the exposure of a representative sample of the French population to 50 Hz MF. The major issues of this study were to select randomly a representative sample and to collect all of necessary data. Measurements were performed in three campaigns at winter time (October to April). The present paper gives the results of the two first campaigns

The innate immune response to coxsackievirus B3 predicts progression to cardiovascular disease and heart failure in male mice

<p>Abstract</p> <p>Background</p> <p>Men are at an increased risk of dying from heart failure caused by inflammatory heart diseases such as atherosclerosis, myocarditis and dilated cardiomyopathy (DCM). We previously showed that macrophages in the spleen are phenotypically distinct in male compared to female mice at 12 h after infection. This innate immune profile mirrors and predicts the cardiac immune response during acute myocarditis.</p> <p>Methods</p> <p>In order to study sex differences in the innate immune response, five male and female BALB/c mice were infected intraperitoneally with coxsackievirus B3 (CVB3) or phosphate buffered saline and their spleens were harvested 12 h later for microarray analysis. Gene expression was determined using an Affymetrix Mouse Gene 1.0 ST Array. Significant gene changes were verified by quantitative real-time polymerase chain reaction or ELISA.</p> <p>Results</p> <p>During the innate immune response to CVB3 infection, infected males had higher splenic expression of genes which are important in regulating the influx of cholesterol into macrophages, such as phospholipase A₂(PLA₂) and the macrophage scavenger receptor compared to the infected females. We also observed a higher expression in infected males compared to infected females of squalene synthase, an enzyme used to generate cholesterol within cells, and Cyp2e1, an enzyme important in metabolizing cholesterol and steroids. Infected males also had decreased levels of the translocator protein 18 kDa (TSPO), which binds PLA₂and is the rate-limiting step for steroidogenesis, as well as decreased expression of the androgen receptor (AR), which indicates receptor activation. Gene differences were not due to increased viral replication, which was unaltered between sexes.</p> <p>Conclusions</p> <p>We found that, compared to females, male mice had a greater splenic expression of genes which are important for cholesterol metabolism and activation of the AR at 12 h after infection. Activation of the AR has been linked to increased cardiac hypertrophy, atherosclerosis, myocarditis/DCM and heart failure in male mice and humans.</p

Evaluation of Wind Potential for an Optimum Choice of Wind Turbine Generator on the Sites of Lomé, Accra, and Cotonou Located in the Gulf of Guinea

This work presents the characterization and assessment of wind energy potential in annual and monthly levels of the sites of Lomé, Accra and Cotonou located in the Gulf of Guinea, and the optimal characteristics of wind turbines to be installed on these sites. Studies of characterization and the wind potential of these sites from the wind speed data collected over a period of thirteen years at a height of 10 meters above the ground, show an annual average speed of 3.52 m/s for Lomé, 3.99 m/s for Cotonou and 4.16 m/s for Accra. These studies also showed that a monthly average speed exceeding 4 m/s was observed on the sites of Cotonou and Accra during the months of February, March, April, July, August and September and during the months of July, August and September on the site of Lomé. After a series of simulation conducted using the software named PotEol that we have developed in Scilab, we have retained that the wind turbines rated speeds of ~8 to 9 m/s at the sites of Lomé and Cotonou and ~ 9 to 10 m/s on the site of Accra would be the most appropriate speeds for optimal exploitation of electric energy from wind farms at a height of 50 m above the ground.Article History: Received May 26th 2016; Received in revised form August 24th 2016; Accepted August 30th 2016; Available onlineHow to Cite This Article: Salami, A.A., Ajavon, A.S.A , Kodjo, M.K. and Bédja, K. (2016) Evaluation of Wind Potential for an Optimum Choice of Wind Turbine Generator on the Sites of Lomé, Accra, and Cotonou Located in the Gulf of Guinea. Int. Journal of Renewable Energy Development, 5(3), 211-223.http://dx.doi.org/10.14710/ijred.5.3.211-22