42 research outputs found

    GASCON : Gestion agro-écologique de la santé des cultures et des organismes nuisibles

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    Le croisement des sciences agronomiques, de l’écologie appliquĂ©e Ă  la gestion des agroĂ©cosystĂšmes,et des sciences humaines et sociales, qu’implique la transition agroĂ©cologique, pose de nouveaux dĂ©fis pour rĂ©pondre aux enjeux agricoles: intĂ©grer des connaissances de diffĂ©rentes disciplines et produites Ă  diffĂ©rentes Ă©chelles d’organisation pour agir en situation; dĂ©velopper des cadres d’analyse et dĂ©marches intĂ©grant la diversitĂ© de situations Ă  gĂ©rer par les acteurs et permettant de construire des rĂ©ponses adaptĂ©es Ă  chaque situation; et concevoir et mettre en Ɠuvre des pratiques d’enseignement et d’apprentissage, qui dotent les apprenants de capacitĂ©s Ă  penser leur action en contexte, en mobilisant des savoirs et savoir-faire multiples en termes de contenus disciplinaires et des savoir-ĂȘtre pour construire des solutions avec une diversitĂ© d’acteurs. Dans le champ de la formation, ces dĂ©fis nĂ©cessitent dĂšs lors de revisiter les contenus des enseignements dispensĂ©s, les modalitĂ©s pĂ©dagogiques et les dispositifs de formation existants, de maniĂšre Ă  apprĂ©hender au mieux la complexitĂ© des processus Ă  l’Ɠuvre. Pour autant, peu de travaux s’attardent sur les modalitĂ©s pratiques de ce changement et de ses implications, alors mĂȘme que de nombreuses initiatives en matiĂšre de pĂ©dagogie et d’agroĂ©cologie se dĂ©veloppent ces derniĂšres annĂ©es. L’objectif de ce sĂ©minaire est de promouvoir une information partagĂ©e et l’échange d’expĂ©riences pour rĂ©pondre aux enjeux posĂ©s par l’agroĂ©cologie dans la formation (transversalitĂ©, pluridisciplinaritĂ©, approche systĂ©mique, pĂ©dagogies actives). Ces enjeux peuvent se dĂ©cliner suivant plusieurs entrĂ©es : les thĂ©matiques enseignĂ©es (agriculture, Ă©levage, territoire, alimentation, ...); les pratiques et les dispositifs pĂ©dagogiques mis en Ɠuvre pour aborder ces questions (enseignement numĂ©rique, dispositifs expĂ©rimentaux, projets professionnels, rĂ©fĂ©rentiels, ...);les publics d’apprenants: Ă©lĂšves, Ă©tudiants, professionnels, ..

    Altimetry for the future: Building on 25 years of progress

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    In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

    Altimetry for the future: building on 25 years of progress

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    In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

    Drosophilids with darker cuticle have higher body temperature under light

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    International audienceAbstract Cuticle pigmentation was shown to be associated with body temperature for several relatively large species of insects, but it was questioned for small insects. Here we used a thermal camera to assess the association between drosophilid cuticle pigmentation and body temperature increase when individuals are exposed to light. We compared mutants of large effects within species ( Drosophila melanogaster ebony and yellow mutants). Then we analyzed the impact of naturally occurring pigmentation variation within species complexes ( Drosophila americana/Drosophila novamexicana and Drosophila yakuba/Drosophila santomea ). Finally we analyzed lines of D. melanogaster with moderate differences in pigmentation. We found significant differences in temperatures for each of the four pairs we analyzed. The temperature differences appeared to be proportional to the differently pigmented area: between Drosophila melanogaster ebony and yellow mutants or between Drosophila americana and Drosophila novamexicana, for which the whole body is differently pigmented, the temperature difference was around 0.6 °C ± 0.2 °C. By contrast, between D. yakuba and D. santomea or between Drosophila melanogaster Dark and Pale lines, for which only the posterior abdomen is differentially pigmented, we detected a temperature difference of about 0.14 °C ± 0.10 °C. This strongly suggests that cuticle pigmentation has ecological implications in drosophilids regarding adaptation to environmental temperature.Il a Ă©tĂ© dĂ©montrĂ© que la pigmentation de la cuticule est associĂ©e Ă  la tempĂ©rature corporelle pour plusieurs espĂšces d'insectes relativement grandes, mais cela a Ă©tĂ© mis en doute pour les petits insectes. Ici, nous avons utilisĂ© une camĂ©ra thermique pour Ă©valuer l'association entre la pigmentation de la cuticule des drosophiles et l'augmentation de la tempĂ©rature corporelle lorsque les individus sont exposĂ©s Ă  la lumiĂšre. Nous avons comparĂ© des mutants avec des effets importants au sein de la mĂȘme espĂšce ( mutants ebony et yellow de Drosophila melanogaster). Puis nous avons analysĂ© l'impact de la variation naturelle de la pigmentation au sein de complexes d'espĂšces ( Drosophila americana/Drosophila novamexicana et Drosophila yakuba/Drosophila santomea ). Enfin, nous avons analysĂ© des lignĂ©es de D. melanogaster prĂ©sentant des diffĂ©rences modĂ©rĂ©es de pigmentation. Nous avons trouvĂ© des diffĂ©rences significatives de tempĂ©rature pour chacune des quatre paires analysĂ©es. Les diffĂ©rences de tempĂ©rature se rĂ©vĂšlent ĂȘtre proportionnelles Ă  la zone diffĂ©remment pigmentĂ©e : entre les mutants ebony et yellow de Drosophila melanogaster ou entre Drosophila americana et Drosophila novamexicana, pour lesquels l'ensemble du corps est diffĂ©remment pigmentĂ©, la diffĂ©rence de tempĂ©rature Ă©tait d'environ 0,6 °C ± 0,2 °C. En revanche, entre D. yakuba et D. santomea ou entre les lignĂ©es Dark et Pale de Drosophila melanogaster, pour lesquelles seule la partie postĂ©rieure de l'abdomen est pigmentĂ©e de maniĂšre diffĂ©rente, nous avons dĂ©tectĂ© une diffĂ©rence de tempĂ©rature d'environ 0,14 °C ± 0,10 °C. Ceci suggĂšre fortement que la pigmentation de la cuticule a des implications Ă©cologiques chez les drosophiles concernant l'adaptation Ă  la tempĂ©rature environnementale

    Diversity of supergene gold expressions and implications for gold targeting in an equatorial regolith (AMG's CouriĂšge exploration prospect, French Guiana)

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    International audienceThe CouriĂšge prospect (French Guiana) provides key examples of the diversity of gold distribution related to supergene processes. The nature of gold in two contrasted weathering profiles is examined as a function of the weathering lithofacies. The autochthonous profile hosts weathered Au-bearing quartz veins whereas the pediment profile is enriched in free gold issued from dismantled gold-bearing quartz veins. The gold distribution is controlled by: (i) the preservation of primary gold as free gold in both transported and autochthonous horizons and as electrum inclusions in detrital pyrite, and (ii) the formation of secondary gold through dissolution/precipitation processes, expressed as gold spherulites on free gold grain surface, Ag-depleted rim around transported free gold grains and Ag-depleted gold micro-inclusions hosted by oxidised autochthonous pyrite. Gold enrichment through supergene chemical processes remains limited within the truncated autochthonous profile. A new conceptual model is proposed for the area, defining the role of chemical and physical processes in gold endowment, and accounting for the geomorphological context. The overall evolution includes (i) deep weathering and peneplenation, (ii) dismantlement and transport of lateritic material, and (iii) development of a latosol cover. This study highlights that gold exploration in tropical environments must consider the residual vs transported nature and the inheritance of targeted pedogenic horizons

    Genetic Variability, Population Differentiation, and Correlations for Thermal Tolerance Indices in the Minute Wasp, Trichogramma cacoeciae

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    International audienceTemperature is a main driver of the ecology and evolution of ectotherms. In particular,the ability to move at sub-lethal low temperatures can be described through three thermal tolerance indices—critical thermal minimum (CTmin), chill coma temperature (CCT), and activity recovery (AR). Although these indices have proven relevant for inter-specific comparisons, little is known about their intraspecific variability as well as possible genetic correlations between them. We thus investigated these two topics (intraspecific variability and genetic correlations between thermal tolerance indices) using the minute wasp, Trichogramma cacoeciae. Strains from T. cacoeciae were sampled across three geographic regions in France—two bioclimatic zones along a sharp altitudinal cline in a Mediterranean context (meso-Mediterranean at low elevations and supra-Mediterranean at higher elevations) and a more northwestern area characterized by continental or mountainousclimates. Our results evidenced a significant effect of both the longitude and the severity of the cold during winter months on CCT. Results were however counter-intuitive since the strains from the two bioclimatic zones characterized by more severe winters (northwestern area and supra-Mediterranean) exhibited opposite patterns. In addition, a strong positive correlation was observed between CCT and CTmin. Neither strain differentiation nor the covariations between traits seem to be linked with the molecular diversity observed on the part of the mitochondrial marker COI
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