86 research outputs found

    Les habiletés sociales : ça s'enseigne, ça s'apprend mais surtout ça se vit au quotidien

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    National audienceUn travail de recherche pour identifier des stratégies d'intervention éducatives permettant la gestion des comportements, et ce, par le biais de l'enseignement des habiletés sociales dans les pratiques ordinaires des enseignants du primaire a été réalisé auprÚs d'enseignants du Québec (2) et de la France (2). Chaque enseignant a été rencontré pour la présentation du programme retenu Pratiquons Ensemble Nos Compétences (PEC, Gendron et al., 2005), de ses modalités d'application et de la méthodologie de la recherche. AprÚs avoir travaillé avec le programme pendant 2 mois, chaque enseignant a été filmé lors d'une séance d'intervention en classe auprÚs des élÚves. Cette séance a été élaborée par l'enseignant ou l'enseignante selon sa propre appropriation de l'outil. Par la suite chacun a été rencontré par les chercheurs pour l'analyse de sa vidéo (auto-confrontation) en ayant soin de commenter quelques passages choisis par lui qui permettaient aux chercheurs de dégager les conceptions qui sont à la base des interventions. Dans un dernier mouvement, les séances d'observation ont été visionnées par tous, permettant des échanges approfondis (confrontations croisées)

    Origine et évolution du manteau cratonique de Sibérie

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    English abstract not supplied by the author. RĂ©sumĂ© en anglais non fourni par l'auteur.. 21 ont des teneurs en Os > 1 ppb et des rapports 187Re/188Os 200km), froid (40 mW/mÂČ) et composĂ© majoritairement par des pĂ©ridotites fortement rĂ©fractaires (Mg#WR>0.92, Al2O3-CaO >100g). Cette thĂšse se base sur une grande collection de xĂ©nolites de pĂ©ridotites (>50) particuliĂšrement fraĂźches i.e. les olivines et les autres minĂ©raux sont prĂ©servĂ©s de l’altĂ©ration et les pertes au feu des roches totales (LOI) sont 30%. Les pĂ©ridotites Ă  spinelle, pauvres en opx ont des compositions en Ă©lĂ©ments majeurs proches d’un rĂ©sidu de fusion. Contrairement aux autres Ă©tudes, leurs compositions en Al2O3, FeO et Mg#WR dĂ©finissent des trends qui, comparĂ©s aux Ă©tudes expĂ©rimentales, indiquent une origine par 38% d’une fusion fractionnĂ©e par dĂ©compression entre 7-4 GPa et ≀1–2 GPa ; ce qui est en accord avec les modĂ©lisations des Ă©lĂ©ments en trace. L’origine des pĂ©ridotites riches en silice est incertaine, et l’hypothĂšse d’une interaction avec des liquides de subduction est peu probable : leurs compositions en SiO2 et FeO diffĂšrent des pĂ©ridotites d’arc, et leur ÎŽ18OWR ~5.3 ± 0.2‰ est proche de la valeur rĂ©fĂ©rence pour le manteau (5.5‰). 1/3 des pĂ©ridotites Ă  grenat grenues a des compositions similaires aux pĂ©ridotites Ă  spinelle et indiquent donc des conditions de formation similaires. Le grenat, dans la majoritĂ© de ces pĂ©ridotites, est d’origine rĂ©siduelle, contrairement au cpx qui lui est clairement d’origine mĂ©tasomatique. La majoritĂ© des pĂ©ridotites Ă  grenat forme des sĂ©quences d’enrichissement en FeO, TiO2 et REE par rapport aux pĂ©ridotites rĂ©siduelles. Cela traduit un mĂ©tasomatisme modal (prĂ©cipitation de cpx et de grenat), et ce par interaction entre le protolite des pĂ©ridotites avec un magma riche en Si, Al, Fe (Ti, REE). Les cpx sont en Ă©quilibre avec un liquide de composition kimberlitique. Les kimberlites sont des magmas pauvres en Si, Al, Fe et ne peuvent pas ĂȘtre responsables du mĂ©tasomatisme modal, mais un magma parent peut avoir interagi avec la roche peu de temps avant l’éruption. 28 pĂ©ridotites ont Ă©tĂ© analysĂ©es pour obtenir leur composition isotopique Re/Os et leur composition en PG

    Origine et évolution du manteau cratonique de Sibérie

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    . 21 ont des teneurs en Os > 1 ppb et des rapports 187Re/188Os 200km), froid (40 mW/m ) et composĂ© majoritairement par des pĂ©ridotites fortement rĂ©fractaires (Mg#WR>0.92, Al2O3-CaO >100g). Cette thĂšse se base sur une grande collection de xĂ©nolites de pĂ©ridotites (>50) particuliĂšrement fraĂźches i.e. les olivines et les autres minĂ©raux sont prĂ©servĂ©s de l altĂ©ration et les pertes au feu des roches totales (LOI) sont 30%. Les pĂ©ridotites Ă  spinelle, pauvres en opx ont des compositions en Ă©lĂ©ments majeurs proches d un rĂ©sidu de fusion. Contrairement aux autres Ă©tudes, leurs compositions en Al2O3, FeO et Mg#WR dĂ©finissent des trends qui, comparĂ©s aux Ă©tudes expĂ©rimentales, indiquent une origine par 38% d une fusion fractionnĂ©e par dĂ©compression entre 7-4 GPa et <=1 2 GPa ; ce qui est en accord avec les modĂ©lisations des Ă©lĂ©ments en trace. L origine des pĂ©ridotites riches en silice est incertaine, et l hypothĂšse d une interaction avec des liquides de subduction est peu probable : leurs compositions en SiO2 et FeO diffĂšrent des pĂ©ridotites d arc, et leur 18OWR ~5.3 +- 0.2 est proche de la valeur rĂ©fĂ©rence pour le manteau (5.5 ). 1/3 des pĂ©ridotites Ă  grenat grenues a des compositions similaires aux pĂ©ridotites Ă  spinelle et indiquent donc des conditions de formation similaires. Le grenat, dans la majoritĂ© de ces pĂ©ridotites, est d origine rĂ©siduelle, contrairement au cpx qui lui est clairement d origine mĂ©tasomatique. La majoritĂ© des pĂ©ridotites Ă  grenat forme des sĂ©quences d enrichissement en FeO, TiO2 et REE par rapport aux pĂ©ridotites rĂ©siduelles. Cela traduit un mĂ©tasomatisme modal (prĂ©cipitation de cpx et de grenat), et ce par interaction entre le protolite des pĂ©ridotites avec un magma riche en Si, Al, Fe (Ti, REE). Les cpx sont en Ă©quilibre avec un liquide de composition kimberlitique. Les kimberlites sont des magmas pauvres en Si, Al, Fe et ne peuvent pas ĂȘtre responsables du mĂ©tasomatisme modal, mais un magma parent peut avoir interagi avec la roche peu de temps avant l Ă©ruption. 28 pĂ©ridotites ont Ă©tĂ© analysĂ©es pour obtenir leur composition isotopique Re/Os et leur composition en PGEEnglish abstract not supplied by the author. RĂ©sumĂ© en anglais non fourni par l'auteur.ST ETIENNE-Bib. Ă©lectronique (422189901) / SudocSudocFranceF

    The Benefits Conferred by Radial Access for Cardiac Catheterization Are Offset by a Paradoxical Increase in the Rate of Vascular Access Site Complications With Femoral Access The Campeau Radial Paradox

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    AbstractObjectivesThe purpose of this study was to assess whether the benefits conferred by radial access (RA) at an individual level are offset by a proportionally greater incidence of vascular access site complications (VASC) at a population level when femoral access (FA) is performed.BackgroundThe recent widespread adoption of RA for cardiac catheterization has been associated with increased rates of VASCs when FA is attempted.MethodsLogistic regression was used to calculate the adjusted VASC rate in a contemporary cohort of consecutive patients (2006 to 2008) where both RA and FA were used, and compared it with the adjusted VASC rate observed in a historical control cohort (1996 to 1998) where only FA was used. We calculated the adjusted attributable risk to estimate the proportion of VASC attributable to the introduction of RA in FA patients of the contemporary cohort.ResultsA total of 17,059 patients were included. At a population level, the VASC rate was higher in the overall contemporary cohort compared with the historical cohort (adjusted rates: 2.91% vs. 1.98%; odds ratio [OR]: 1.48, 95% confidence interval [CI]: 1.17 to 1.89; p = 0.001). In the contemporary cohort, RA patients experienced fewer VASC than FA patients (adjusted rates: 1.44% vs. 4.19%; OR: 0.33, 95% CI: 0.23 to 0.48; p < 0.001). We observed a higher VASC rate in FA patients in the contemporary cohort compared with the historical cohort (adjusted rates: 4.19% vs. 1.98%; OR: 2.16, 95% CI: 1.67 to 2.81; p < 0.001). This finding was consistent for both diagnostic and therapeutic catheterizations separately. The proportion of VASCs attributable to RA in the contemporary FA patients was estimated at 52.7%.ConclusionsIn a contemporary population where both RA and FA were used, the safety benefit associated with RA is offset by a paradoxical increase in VASCs among FA patients. The existence of this radial paradox should be taken into consideration, especially among trainees and default radial operators

    Y1 and Y5 Receptors Are Both Required for the Regulation of Food Intake and Energy Homeostasis in Mice

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    Neuropeptide Y (NPY) acting in the hypothalamus is one of the most powerful orexigenic agents known. Of the five known Y receptors, hypothalamic Y1 and Y5 have been most strongly implicated in mediating hyperphagic effects. However, knockout of individual Y1 or Y5 receptors induces late-onset obesity – and Y5 receptor knockout also induces hyperphagia, possibly due to redundancy in functions of these genes. Here we show that food intake in mice requires the combined actions of both Y1 and Y5 receptors. Germline Y1Y5 ablation in Y1Y5−/− mice results in hypophagia, an effect that is at least partially mediated by the hypothalamus, since mice with adult-onset Y1Y5 receptor dual ablation targeted to the paraventricular nucleus (PVN) of the hypothalamus (Y1Y5Hyp/Hyp) also exhibit reduced spontaneous or fasting-induced food intake when fed a high fat diet. Interestingly, despite hypophagia, mice with germline or hypothalamus-specific Y1Y5 deficiency exhibited increased body weight and/or increased adiposity, possibly due to compensatory responses to gene deletion, such as the decreased energy expenditure observed in male Y1Y5−/− animals relative to wildtype values. While Y1 and Y5 receptors expressed in other hypothalamic areas besides the PVN – such as the dorsomedial nucleus and the ventromedial hypothalamus – cannot be excluded from having a role in the regulation of food intake, these studies demonstrate the pivotal, combined role of both Y1 and Y5 receptors in the mediation of food intake

    Large trees drive forest aboveground biomass variation in moist lowland forests accross the tropics

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    peer reviewedaudience: researcher, professional, studentAim Large trees (d.b.h. 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore which intrinsic (species trait) and extrinsic (environment) variables are associated with the density of large trees and forest biomass at continental and pan-tropical scales. Location Pan-tropical. Methods Aboveground biomass (AGB) was calculated for 120 intact lowland moist forest locations. Linear regression was used to calculate variation in AGB explained by the density of large trees. Akaike information criterion weights (AICcwi) were used to calculate averaged correlation coefficients for all possible multiple regression models between AGB/density of large trees and environmental and species trait variables correcting for spatial autocorrelation. Results Density of large trees explained c. 70% of the variation in pan-tropical AGB and was also responsible for significantly lower AGB in Neotropical [287.8 (mean) 105.0 (SD) Mg ha-1] versus Palaeotropical forests (Africa 418.3 91.8 Mg ha-1; Asia 393.3 109.3 Mg ha-1). Pan-tropical variation in density of large trees and AGB was associated with soil coarseness (negative), soil fertility (positive), community wood density (positive) and dominance of wind dispersed species (positive), temperature in the coldest month (negative), temperature in the warmest month (negative) and rainfall in the wettest month (positive), but results were not always consistent among continents. Main conclusions Density of large trees and AGB were significantly associated with climatic variables, indicating that climate change will affect tropical forest biomass storage. Species trait composition will interact with these future biomass changes as they are also affected by a warmer climate. Given the importance of large trees for variation in AGB across the tropics, and their sensitivity to climate change, we emphasize the need for in-depth analyses of the community dynamics of large trees

    An estimate of the number of tropical tree species

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    The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∌40,000 and ∌53,000, i.e. at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∌19,000–25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∌4,500–6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa

    Long-term thermal sensitivity of Earth’s tropical forests

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    The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate

    The global abundance of tree palms

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    Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≄10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests
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