Introduction d’approches socioconstructivistes dans le cours d’éducation physique. Avis des acteurs sur l’utilisation de fiches d’observation et du débat d’idées

Dans l’enseignement de l’éducation physique et des sports, l’inspiration socioconstructiviste prend une place croissante depuis plus d’une vingtaine d’années. Si les discours théoriques, soutenus par des résultats de recherches en Intervention, semblent convaincre les praticiens dans les pays anglo-saxons et être intégrés dans les habitudes de plusieurs pays francophones, nous avons montré que les professeurs d’éducation physique de la Fédération Wallonie-Bruxelles restaient largement fidèles à une approche traditionnelle, techniciste et dominée par l’intervenant. Dans cet article, nous analysons deux cycles de quatre séances de volley-ball, expérimentés par trois enseignants du secondaire dans la perspective de tester deux approches didactiques impliquant directement les élèves dans leurs apprentissages : l’utilisation de fiches d’observation et le débat d’idées. Dans les limites de l’étude, les résultats montrent que les enseignants et les élèves ont vécu favorablement les expériences, les premiers éprouvant toutefois de réelles difficultés à s’ « effacer » pour laisser leurs élèves apprendre par eux-mêmes. Davantage de ressources devraient encore être développées avec les enseignants pour leur permettre d’intégrer plus rapidement ces « nouvelles » approches.In physical education teaching, the socio constructivist approach takes a growing emphasis since more than two decades. If the theoretical discourses supported by findings of sport pedagogy researches seem to convince practitioners in Anglo-Saxon countries and integrated into the teaching habits in several French speaking countries, we showed that physical education teachers of the French speaking region of Belgium remained in majority attached to a traditional and technique focused approach, dominated by the educator. In this paper, we analyse two volleyball units comprising four lessons, implemented by three secondary PE school teachers in the perspective to test two didactic approaches involving directly the students in their learning: use of observation sheets and debate of ideas. In the limits of the study, the findings show that the teachers and the students positively lived the experiences. However, the teachers felt real difficulties to let the students to learn by themselves. More resources should be developed with the teachers in order to allow them to integrate more quickly these ‘new’ approaches

Increased acetylcholinesterase expression in bumble bees during neonicotinoid-coated corn sowing

While honey bee exposure to systemic insecticides has received much attention, impacts on wild pollinators have not been as widely studied. Neonicotinoids have been shown to increase acetylcholinesterase (AChE) activity in honey bees at sublethal doses. High AChE levels may therefore act as a biomarker of exposure to neonicotinoids. This two-year study focused on establishing whether bumble bees living and foraging in agricultural areas using neonicotinoid crop protection show early biochemical signs of intoxication. Bumble bee colonies (Bombus impatiens) were placed in two different agricultural cropping areas: 1) control (≥3 km from fields planted with neonicotinoid-treated seeds) or 2) exposed (within 500 m of fields planted with neonicotinoid-treated seeds) and maintained for the duration of corn sowing. As determined by Real Time qPCR, AChE mRNA expression was initially significantly higher in bumble bees from exposed sites, then decreased throughout the planting season to reach a similar endpoint to that of bumble bees from control sites. These findings suggest that exposure to neonicotinoid seed coating particles during the planting season can alter bumble bee neuronal activity. To our knowledge, this is the first study to report in situ that bumble bees living in agricultural areas exhibit signs of neonicotinoid intoxication

AMS-02 antiprotons and dark matter: Trimmed hints and robust bounds

Based on 4 yr AMS-02 antiproton data, we present bounds on the dark matter (DM) annihilation cross section vs. mass for some representative final state channels. We use recent cosmic-ray propagation models, a realistic treatment of experimental and theoretical errors, and an updated calculation of input antiproton spectra based on a recent release of the PYTHIA code. We find that reported hints of a DM signal are statistically insignificant; an adequate treatment of errors is crucial for credible conclusions. Antiproton bounds on DM annihilation are among the most stringent ones, probing thermal DM up to the TeV scale. The dependence of the bounds upon propagation models and the DM halo profile is also quantified. A preliminary estimate reaches similar conclusions when applied to the 7 years AMS-02 dataset, but also suggests extra caution as for possible future claims of DM excesses.Comment: v2: 33 pages, 6 figures (two of which in two panels); clarifications and a couple of references added, conclusions unchange

Dietary contamination with a neonicotinoid (clothianidin) gradient triggers specific dysbiosis signatures of microbiota activity along the honeybee (Apis mellifera) digestive tract

Pesticides are increasing honeybee (Apis mellifera) death rates globally. Clothianidin neonicotinoid appears to impair the microbe–immunity axis. We conducted cage experiments on newly emerged bees that were 4–6 days old and used a 16S rRNA metataxonomic approach to measure the impact of three sublethal clothianidin concentrations (0.1, 1 and 10 ppb) on survival, sucrose syrup consumption and gut microbiota community structure. Exposure to clothianidin significantly increased mortality in the three concentrations compared to controls. Interestingly, the lowest clothianidin concentration was associated with the highest mortality, and the medium concentration with the highest food intake. Exposure to clothianidin induced significant variation in the taxonomic distribution of gut microbiota activity. Co-abundance network analysis revealed local dysbiosis signatures specific to each gut section (midgut, ileum and rectum) were driven by specific taxa. Our findings confirm that exposure to clothianidin triggers a reshuffling of beneficial strains and/or potentially pathogenic taxa within the gut, suggesting a honeybee’s symbiotic defense systems’ disruption, such as resistance to microbial colonization. This study highlights the role of weak transcriptional activity taxa in maintaining a stable honeybee gut microbiota. Finally, the early detection of gut dysbiosis in honeybees is a promising biomarker in hive management for assessing the impact exposure to sublethal xenobiotics

The yellow perch (Perca flavescens) microbiome revealed resistance to colonisation mostly associated with neutralism driven by rare taxa under cadmium disturbance

Background: Disentangling the dynamics of microbial interactions within communities improves our comprehension of metacommunity assembly of microbiota during host development and under perturbations. To assess the impact of stochastic variation of neutral processes on microbiota structure and composition under disturbance, two types of microbial habitats, free-living (water), and host-associated (skin and gut) were experimentally exposed to either a constant or gradual selection regime exerted by two sublethal cadmium chloride dosages (CdCl2). Yellow Perch (Perca flavescens) was used as a piscivorous ecotoxicological model. Using 16S rDNA gene based metataxonomics, quantitative diversity metrics of water, skin and gut microbial communities were characterized along with development and across experimental conditions. Results: After 30 days, constant and gradual selection regimes drove a significant alpha diversity increase for both skin and gut microbiota. In the skin, pervasive negative correlations between taxa in both selection regimes in addition to the taxonomic convergence with the environmental bacterial community, suggest a loss of colonisation resistance resulting in the dysbiosis of yellow perch microbiota. Furthermore, the network connectivity in gut microbiome was exclusively maintained by rare (low abundance) OTUs, while most abundant OTUs were mainly composed of opportunistic invaders such as Mycoplasma and other genera related to fish pathogens such as Flavobacterium. Finally, the mathematical modelling of community assembly using both non-linear least squares models (NLS) based estimates of migration rates and normalized stochasticity ratios (NST) based beta-diversity distances suggested neutral processes drove by taxonomic drift in host and water communities for almost all treatments. The NLS models predicted higher demographic stochasticity in the cadmium-free host and water microbiomes, however, NST models suggested higher ecological stochasticity under perturbations. Conclusions: Neutral models agree that water and host-microbiota assembly promoted by rare taxa have evolved predominantly under neutral processes with potential involvement of deterministic forces sourced from host filtering and cadmium selection. The early signals of perturbations in the skin microbiome revealed antagonistic interactions by a preponderance of negative correlations in the co-abundance networks. Our findings enhance our understanding of community assembly host-associated and free-living under anthropogenic selective pressure

Revue d'histoire du Bas-Saint-Laurent, vol. 12 (3-4)

Mot de l'éditeur -- Au micro de CJBR -- La grande histoire de CJBR -- Jules-A. Brillant et le poste CJBR -- Avec CJBR, un bon en avant pour le Bas St-Laurent -- CJBR, l'école -- L'annonceur: un éducateur populaire -- Sandy Burgess : le journaliste que j'ai connu -- "Ce pays qui est le mien" -- Un demi-siècle d'information: que de nouvelles! -- Journaliste de père en fils à CJBR -- Le théâtre à CJBR -- 50 ans de musique à CJBR, le château fort de la mélodie française -- Poésie, théâtre, jazz et originalité avec Michel Garneau -- Les "Chroniques du dimanche", l'âge d'or de la critique culturelle à CJBR -- "Si CJBR m'était conté..." -- L'évolution technologique, un élément-clef de l'histoire des 50 ans de radiodiffusion -- La publicité à CJBR, quarante ans de croissance -- Des pionnières à CJBR -- 1958-1972, des années enrichissantes -- De Trois-Pistoles à Rimouski -- Le sport et son enracinement dans le milieu régional -- "Debout c'est l'heure", c'est Jean Brisson qui sonne le réveil -- "Par une belle journée de tempête" -- Et on repart vers la centain

Large-Scale Selective Sweep among Segregation Distorter Chromosomes in African Populations of Drosophila melanogaster

Segregation Distorter (SD) is a selfish, coadapted gene complex on chromosome 2 of Drosophila melanogaster that strongly distorts Mendelian transmission; heterozygous SD/SD+ males sire almost exclusively SD-bearing progeny. Fifty years of genetic, molecular, and theory work have made SD one of the best-characterized meiotic drive systems, but surprisingly the details of its evolutionary origins and population dynamics remain unclear. Earlier analyses suggested that the SD system arose recently in the Mediterranean basin and then spread to a low, stable equilibrium frequency (1–5%) in most natural populations worldwide. In this report, we show, first, that SD chromosomes occur in populations in sub-Saharan Africa, the ancestral range of D. melanogaster, at a similarly low frequency (∼2%), providing evidence for the robustness of its equilibrium frequency but raising doubts about the Mediterranean-origins hypothesis. Second, our genetic analyses reveal two kinds of SD chromosomes in Africa: inversion-free SD chromosomes with little or no transmission advantage; and an African-endemic inversion-bearing SD chromosome, SD-Mal, with a perfect transmission advantage. Third, our population genetic analyses show that SD-Mal chromosomes swept across the African continent very recently, causing linkage disequilibrium and an absence of variability over 39% of the length of the second chromosome. Thus, despite a seemingly stable equilibrium frequency, SD chromosomes continue to evolve, to compete with one another, or evade suppressors in the genome

Implementation of socioconstructivist approaches in physical education lessons. Opinions of the actors on observation cards and students' verbal exchanges

peer reviewedDans l’enseignement de l’éducation physique et des sports, l’inspiration socioconstructiviste prend une place croissante depuis plus d’une vingtaine d’années. Si les discours théoriques, soutenus par des résultats de recherches en Intervention, semblent convaincre les praticiens dans les pays anglo-saxons et être intégrés dans les habitudes de plusieurs pays francophones, nous avons montré que les professeurs d’éducation physique de la Fédération Wallonie-Bruxelles restaient largement fidèles à une approche traditionnelle, techniciste et dominée par l’intervenant. Dans cet article, nous analysons deux cycles de quatre séances de volley-ball, expérimentés par trois enseignants du secondaire dans la perspective de tester deux approches didactiques impliquant directement les élèves dans leurs apprentissages : l’utilisation de fiches d’observation et le débat d’idées. Dans les limites de l’étude, les résultats montrent que les enseignants et les élèves ont vécu favorablement les expériences, les premiers éprouvant toutefois de réelles difficultés à s’ « effacer » pour laisser leurs élèves apprendre par eux-mêmes. Davantage de ressources devraient encore être développées avec les enseignants pour leur permettre d’intégrer plus rapidement ces « nouvelles » approches.Two specific teaching approaches respecting the socioconstructivist principles (observation cards and students verbal exchanges) have been implemented in three secondary PE school classes during short teaching volleyball units. The study examines the opinions of the teachers and students about their experience. Both kind of actors were positively surprised by these original teaching approaches. PE teachers had some difficulties to share the leadership with their students but were impressed by the behavior of their students. The latter underlined that they appreciated to have the opportunity to learn by themselves. More resources should be developed to help the PE teachers to adopt such teaching approaches

Endogenous Honeybee Gut Microbiota Metabolize the Pesticide Clothianidin

Including probiotics in honeybee nutrition represents a promising solution for mitigating diseases, and recent evidence suggests that various microbes possess mechanisms that can bioremediate environmental pollutants. Thus, the use of probiotics capable of degrading pesticides used in modern agriculture would help to both reduce colony losses due to the exposure of foragers to these toxic molecules and improve honeybee health and wellbeing globally. We conducted in vitro experiments to isolate and identify probiotic candidates from bacterial isolates of the honeybee gut (i.e., endogenous strains) according to their ability to (i) grow in contact with three sublethal concentrations of the pesticide clothianidin (0.15, 1 and 10 ppb) and (ii) degrade clothianidin at 0.15 ppb. The isolated bacterial strains were indeed able to grow in contact with the three sublethal concentrations of clothianidin. Bacterial growth rate differed significantly depending on the probiotic candidate and the clothianidin concentration used. Clothianidin was degraded by seven endogenous honeybee gut bacteria, namely Edwardsiella sp., two Serratia sp., Rahnella sp., Pantoea sp., Hafnia sp. and Enterobacter sp., measured within 72 h under in vitro conditions. Our findings highlight that endogenous bacterial strains may constitute the base material from which to develop a promising probiotic strategy to mitigate the toxic effects of clothianidin exposure on honeybee colony health