78 research outputs found
Natal dispersal and diving behaviour ontogeny in juvenile Emperor penguins Aptenodytes forsteri from Adélie Land
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Labraunda 2016
La mission 2016 de Labraunda sâest dĂ©roulĂ©e du 10 juillet au 17 septembre 2016. Les Ă©vĂ©nements politiques turcs qui se sont dĂ©roulĂ©s peu aprĂšs le dĂ©but des opĂ©rations, sâils ont eu un certain impact sur la fouille, avec notamment le renoncement de quelques participants, nâont toutefois pas dĂ©sorganisĂ© les travaux prĂ©vus. Dans la lignĂ©e des annĂ©es prĂ©cĂ©dentes, nous avons travaillĂ©, avec succĂšs, dâune part Ă la consolidation de notre implantation locale, par des accords de collaboration (avec l..
Labraunda 2014
La saison 2014 Ă Labraunda (Fig. 1) a probablement Ă©tĂ© la plus intense depuis les grands travaux entrepris par lâĂ©quipe suĂ©doise sous la direction dâAlfred Westholm en 1960. GrĂące au soutien des trĂšs nombreuses institutions, publiques comme privĂ©es, et de personnalitĂ©s physiques, nous avons pu rĂ©unir sur le terrain une Ă©quipe internationale de 47 chercheurs et Ă©tudiants de onze nationalitĂ©s diffĂ©rentes (dâOuest en Est : Ătats-Unis, Colombie, Royaume-Uni, France, SuĂšde, Finlande, Slovaquie, Gr..
Amélioration de la détermination des propriétés de résistance de l'interface béton-rocher et des discontinuités des fondations rocheuses des barrages poids
CIGB 2018, 26Ú CongrÚs des Grands Barrages, Vienne, AUTRICHE, 01-/07/2018 - 07/07/2018La détermination des caractéristiques mécaniques régissant la stabilité d'un barrage existant peut s'avérer complexe notamment en ce qui concerne les discontinuités présentes en fondation et à l'interface barrage-fondation. Ces caractéristiques sont la résistance à la traction, la cohésion et l'angle de frottement. Fort de ce constat, IRSTEA et EDF ont lancé des travaux de recherche ces derniÚres années de maniÚre d'une part à créer des données utiles à la compréhension des mécanismes de rupture et d'autre part à proposer des méthodologies d'estimation des caractéristiques mécaniques utilisables directement par l'ingénierie. Le présent article donne les principaux résultats des essais de traction et de cisaillement sur des interfaces béton-rocher. Ces résultats pourraient faire l'objet d'échange et de partage avec les ingénieries intéressées par le sujet. L'article présente également des méthodologies de détermination des caractéristiques de discontinuités rocheuses en cisaillement ainsi que des caractéristiques de résistance à la traction de l'interface béton-rocher. Des perspectives sont proposées quant à de futures actions de recherche prometteuses telles que la caractérisation de la cohésion apparente des discontinuités rocheuses et l'estimation de la géométrie du contact barrage-fondation par des méthodes non-destructives
EHD2 is a mechanotransducer connecting caveolae dynamics with gene transcription
Caveolae are small invaginated pits that function as dynamic mechanosensors to buffer tension variations at the plasma membrane. Here we show that under mechanical stress, the EHD2 ATPase is rapidly released from caveolae, SUMOylated, and translocated to the nucleus, where it regulates the transcription of several genes including those coding for caveolae constituents. We also found that EHD2 is required to maintain the caveolae reservoir at the plasma membrane during the variations of membrane tension induced by mechanical stress. Metal-replica electron microscopy of breast cancer cells lacking EHD2 revealed a complete absence of caveolae and a lack of gene regulation under mechanical stress. Expressing EHD2 was sufficient to restore both functions in these cells. Our findings therefore define EHD2 as a central player in mechanotransduction connecting the disassembly of the caveolae reservoir with the regulation of gene transcription under mechanical stress
Labraunda 2017
La mission 2017 de Labraunda a Ă©tĂ© double. ParallĂšlement Ă la mission de fouille/documentation/conservation qui sâest dĂ©roulĂ©e sur le site de Labraunda du 18 juin au 18 aoĂ»t 2017, nous avons inaugurĂ© cette annĂ©e une mission de prospection, pour lâinstant modeste, mais qui sâavĂšre trĂšs prometteuse. Cette derniĂšre, dont la premiĂšre Ă©dition sâest dĂ©roulĂ©e pendant les deux semaines qui ont prĂ©cĂ©dĂ© la fouille, a pour objectif dâĂ©tablir une carte archĂ©ologique de la rĂ©gion de Labraunda et de permet..
Comprehensive genetic dissection of wood properties in a widely-grown tropical tree: Eucalyptus
Background: Eucalyptus is an important genus in industrial plantations throughout the world and is grown for use as timber, pulp, paper and charcoal. Several breeding programmes have been launched worldwide to concomitantly improve growth performance and wood properties (WPs). In this study, an interspecific cross between Eucalyptus urophylla and E. grandis was used to identify major genomic regions (Quantitative Trait Loci, QTL) controlling the variability of WPs. Results: Linkage maps were generated for both parent species. A total of 117 QTLs were detected for a series of wood and end-use related traits, including chemical, technological, physical, mechanical and anatomical properties. The QTLs were mainly clustered into five linkage groups. In terms of distribution of QTL effects, our result agrees with the typical L-shape reported in most QTL studies, i.e. most WP QTLs had limited effects and only a few (13) had major effects (phenotypic variance explained > 15%). The co-locations of QTLs for different WPs as well as QTLs and candidate genes are discussed in terms of phenotypic correlations between traits, and of the function of the candidate genes. The major wood property QTL harbours a gene encoding a Cinnamoyl CoA reductase (CCR), a structural enzyme of the monolignol-specific biosynthesis pathway. Conclusions: Given the number of traits analysed, this study provides a comprehensive understanding of the genetic architecture of wood properties in this Eucalyptus full-sib pedigree. At the dawn of Eucalyptus genome sequence, it will provide a framework to identify the nature of genes underlying these important quantitative traits. (Résumé d'auteur
The retrospective analysis of Antarctic tracking data project
The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for multiple species of Antarctic meso- and top-predators to identify Areas of Ecological Significance. These datasets and accompanying syntheses provide a greater understanding of fundamental ecosystem processes in the Southern Ocean, support modelling of predator distributions under future climate scenarios and create inputs that can be incorporated into decision making processes by management authorities. In this data paper, we present the compiled tracking data from research groups that have worked in the Antarctic since the 1990s. The data are publicly available through biodiversity.aq and the Ocean Biogeographic Information
System. The archive includes tracking data from over 70 contributors across 12 national Antarctic programs, and includes data from 17 predator species, 4060 individual animals, and over 2.9 million observed locations
Reproductive performance and diving behaviour share a common sea-ice concentration optimum in Adélie penguins (Pygoscelis adeliae)
This study was financially supported by the following institutions: the WWF-UK through R. Downie, the Japanese Mombukagakusho and the Japanese Society for the Promotion of Science, the Zone Atelier Antarctique et Subantarctique âLTER France of the CNRS.The Southern Ocean is currently experiencing major environmental changes, including in seaâice cover. Such changes strongly influence ecosystem structure and functioning and affect the survival and reproduction of predators such as seabirds. These effects are likely mediated by reduced availability of food resources. As such, seabirds are reliable ecoâindicators of environmental conditions in the Antarctic region. Here, based on 9 years of seaâice data, we found that the breeding success of AdĂ©lie penguins (Pygoscelis adeliae) reaches a peak at intermediate seaâice cover (ca. 20%). We further examined the effects of seaâice conditions on the foraging activity of penguins, measured at multiple scales from individual dives to foraging trips. Analysis of temporal organisation of dives, including fractal and bout analyses, revealed an increasingly consistent behaviour during years with extensive seaâice cover. The relationship between several dive parameters and seaâice cover in the foraging area appears to be quadratic. In years of low and high seaâice cover, individuals adjusted their diving effort by generally diving deeper, more frequently and by resting at the surface between dives for shorter periods of time than in years with intermediate seaâice cover. Our study therefore suggests that seaâice cover is likely to affect the reproductive performance of AdĂ©lie penguins through its effects on foraging behaviour, as breeding success and most diving parameters share a common optimum. Some years, however, deviated from this general trend, suggesting that other factors (e.g. precipitation during the breeding season) might sometimes become preponderant over the seaâice effects on breeding and foraging performance. Our study highlights the value of monitoring fitness parameters and individual behaviour concomitantly over the longâterm to better characterize optimal environmental conditions and potential resilience of wildlife. Such an approach is crucial if we want to anticipate the effects of environmental change on Antarctic penguin populations.PostprintPeer reviewe
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