79 research outputs found
Du naturaliste expert Ă lâĂ©lĂšve : Enjeux de la diversification des objectifs dâun programme de sciences participatives en France
Vigie-Nature est un programme de sciences participatives dĂ©veloppĂ© par le MusĂ©um national dâHistoire naturelle français, regroupant plusieurs observatoires de la biodiversitĂ©. Ces observatoires proposent Ă chacun, selon ses connaissances, ses disponibilitĂ©s et son intĂ©rĂȘt, de collecter des informations standardisĂ©es sur la biodiversitĂ©. Visant initialement un public de naturalistes amateurs - avec lâobjectif dâaugmenter les couvertures spatiale et temporelle des donnĂ©es disponibles pour la recherche en Ă©cologie - Vigie-Nature sâest progressivement ouvert Ă dâautres publics : citoyens non-experts, professionnels de la Nature et scolaires. Ă travers une remise en contexte sociĂ©tal et technologique, cet article explore lâĂ©volution de lâoffre de ce programme dans les observatoires au cours de ses trente annĂ©es dâexistence, et discute la diversification et la nĂ©cessaire articulation des objectifs qui en ont dĂ©coulĂ©. En effet, des questions dâĂ©ducation relative Ă lâenvironnement ont tout dâabord Ă©tĂ© mises Ă jour avec lâentrĂ©e dans la gestion du programme de nouvelles parties prenantes lors de la crĂ©ation des observatoires Ă destination de publics non experts. Puis, le dĂ©ploiement de Vigie-Nature Ăcole - dĂ©clinaison scolaire du programme Vigie-Nature - a placĂ© lâenjeu pĂ©dagogique au cĆur de lâanimation et de la conception dâoutils spĂ©cifiques. Finalement, il apparait que la diversification des objectifs ne porte pas prĂ©judice aux ambitions originelles du programme, dĂšs lors quâils sâarticulent autour dâune visĂ©e commune : la conservation de la biodiversitĂ©.Vigie-Nature is a citizen science program developed by the French National Museum of Natural History, bringing together several biodiversity monitorings. These monitorings propose to everyone, according to their knowledge, availability and interest, to collect standardized information on biodiversity. Initially targeting an audience of naturalists - with the objective of increasing the spatial and temporal coverage of data available for ecological research - Vigie-Nature has gradually opened up to other audiences : non-expert citizens, nature professionals and school students. Through a review of the societal and technological context, this article explores the evolution of Vigie-Nature during its thirty years of existence, and discusses the diversification and the necessary articulation of the objectives that have emerged from this evolution
A Phase Field Approach to Limited-angle Tomographic Reconstruction
The tomography of an object with limited angle can be addressed through Iterative Reconstruction Reprojection (IRR) procedure, wherein a standard reconstruction procedure is used together with a âfilteringâ of the image at each iteration. It is here proposed to use as a filter a phase-fieldâor Cahn-Hilliardâregularization interlaced with a filtered back-projection reconstruction. This reconstruction procedure is tested on a cone-beam tomography of a 3D woven ceramic composite material, and is shown to retrieve a reconstructed volume with very low artifacts in spite of a large missing angle interval (up to 28%)
Itinéraires thérapeutiques dans la société contemporaine
La massification du recours aux thĂ©rapies alternatives dans les sociĂ©tĂ©s occidentales est ici interrogĂ©e au travers de lâanalyse des itinĂ©raires thĂ©rapeutiques des patients. Celle-ci met en Ă©vidence une conjugaison systĂ©matique et rĂ©currente des usages de la mĂ©decine biomĂ©dicale et des mĂ©decines alternatives. Si la mĂ©decine biomĂ©dicale remplit une fonction de rĂ©assurance pour le patient, les thĂ©rapies alternatives se prĂ©sentent comme les espaces privilĂ©giĂ©s de la quĂȘte, par la mĂ©diation du corps, dâun « au-delà  » du monde techno-scientifique. Les thĂ©rapies alternatives peuvent-elles alors se comprendre comme des lieux dans lesquels se vit un rĂ©-enchantement du monde, facilitant lâadaptation ?Therapeutic itineraries in contemporary society. The massification of the recourse to alternative therapies in occidental societes is questioned here through the analysis of therapeutic itineraries of patients. This one highlights a systematic and recurring combined use of biomedical medicine and alternative medicines. If biomedical medicine fulfills a function of reinsurance for the patient, alternative therapies are presented in the form of privileged spaces of the search, by the mediation of the body, of a world beyond the techno-scientistâs world. Can alternative therapies then be understood as places in which is lived a worldâs re-enchantement, facilitating adaptationÂ
Exclusion from the Golgi and very low levels of HTLV-2 Tax ubiquitination do not prevent IKK-gamma/NEMO relocalization and NF-ÎșB activation
International audiencen.
Gem-Induced Cytoskeleton Remodeling Increases Cellular Migration of HTLV-1-Infected Cells, Formation of Infected-to-Target T-Cell Conjugates and Viral Transmission
International audienceEfficient HTLV-1 viral transmission occurs through cell-to-cell contacts. The Tax viral transcriptional activator protein facilitates this process. Using a comparative transcriptomic analysis, we recently identified a series of genes up-regulated in HTLV-1 Tax expressing T-lymphocytes. We focused our attention towards genes that are important for cytoskeleton dynamic and thus may possibly modulate cell-to-cell contacts. We first demonstrate that Gem, a member of the small GTP-binding proteins within the Ras superfamily, is expressed both at the RNA and protein levels in Tax-expressing cells and in HTLV-1-infected cell lines. Using a series of ChIP assays, we show that Tax recruits CREB and CREB Binding Protein (CBP) onto a cAMP Responsive Element (CRE) present in the gem promoter. This CRE sequence is required to drive Tax-activated gem transcription. Since Gem is involved in cytoskeleton remodeling, we investigated its role in infected cells motility. We show that Gem co-localizes with F-actin and is involved both in T-cell spontaneous cell migration as well as chemotaxis in the presence of SDF-1/CXCL12. Importantly, gem knock-down in HTLV-1-infected cells decreases cell migration and conjugate formation. Finally, we demonstrate that Gem plays an important role in cell-to-cell viral transmission
Low levels of HTLV-2 Tax conjugation to ubiquitin and SUMO do not impede Tax-mediated activation of NF-ÎșB
International audienc
Reconstructing extreme AMOC events through nudging of the ocean surface: a perfect model approach
While the Atlantic Meridional Overturning Circulation (AMOC) is thought to be a crucial component of the North Atlantic climate, past changes in its strength are challenging to quantify, and only limited information is available. In this study, we use a perfect model approach with the IPSL-CM5A-LR model to assess the performance of several surface nudging techniques in reconstructing the variability of the AMOC. Special attention is given to the reproducibility of an extreme positive AMOC peak from a preindustrial control simulation. Nudging includes standard relaxation techniques towards the sea surface temperature and salinity anomalies of this target control simulation, and/or the prescription of the wind-stress fields.
Surface nudging approaches using standard fixed restoring terms succeed in reproducing most of the target AMOC variability, including the timing of the extreme event, but systematically underestimate its amplitude. A detailed analysis of the AMOC variability mechanisms reveals that the underestimation of the extreme AMOC maximum comes from a deficit in the formation of the dense water masses in the main convection region, located south of Iceland in the model. This issue is largely corrected after introducing a novel surface nudging approach, which uses a varying restoring coefficient that is proportional to the simulated mixed layer depth, which, in essence, keeps the restoring time scale constant. This new technique substantially improves water mass transformation in the regions of convection, and in particular, the formation of the densest waters, which are key for the representation of the AMOC extreme. It is therefore a promising strategy that may help to better constrain the AMOC variability and other ocean features in the models. As this restoring technique only uses surface data, for which better and longer observations are available, it opens up opportunities for improved reconstructions of the AMOC over the last few decades
Lâapport de Vigie-Nature dans lâĂ©ducation Ă la biodiversitĂ© (France)
International audienceVigie-Nature est un dispositif de sciences participatives portĂ© par le MusĂ©um national dâHistoire naturelle. Dans ce dispositif, des citoyens volontaires vont collecter, via des protocoles simples et standardisĂ©s, des donnĂ©es sur un grand nombre de sites rĂ©partis sur toute la France. Un des axes de recherche de notre Ă©quipe est dâĂ©valuer lâimpact des pratiques humaines sur la biodiversitĂ©. A titre dâexemple, nous prĂ©senterons des rĂ©sultats basĂ©s sur les donnĂ©es issues de lâObservatoire des jardins. Cette Ă©tude a permis dâĂ©valuer lâeffet de lâutilisation de pesticides sur lâabondance de papillons et de bourdons dans des jardins de particuliers. Dâautres rĂ©sultats prĂ©liminaires montrent un effet de la participation sur le comportement de nos observateurs : ils utilisent de moins en moins dâengrais ou de pesticides. Outre le grand public, nous souhaitons impliquer les scolaires dans ces dĂ©marches participatives. Vigie-Nature Ăcole (VNE) propose donc aux enseignants et Ă leurs Ă©lĂšves de rĂ©aliser des suivis de biodiversitĂ©. Sept protocoles permettent dâĂ©tudier des groupes variĂ©s (des escargots aux plantes sauvages en passant par les chauves-sourisâŠ). En 2015-2016, prĂšs de 6500 Ă©lĂšves, de la maternelle au lycĂ©e, ont participĂ© Ă ce dispositif. Nous prĂ©senterons les rĂ©sultats dâune Ă©tude montrant que les Ă©lĂšves participant Ă VNE dĂ©clarent sâintĂ©resser davantage Ă la biodiversitĂ© de leur Ă©tablissement et placent plus dâĂ©lĂ©ments naturels dans les dessins que nous leur avons demandĂ©s
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