Traitement des diagraphies acoustiques. Troisième partie : caractérisation d'un réservoir par diagraphies acoustiques obtenues avec un outil dipolaire

En formation lente, l'utilisation d'un outil acoustique équipé d'émetteurs et de récepteurs dipolaires permet d'accéder à la lenteur S de la formation. Nous montrons comment un tel outil peut être utilisé pour caractériser un réservoir en formation lente. Le pointé des premières arrivées des différentes ondes composant un enregistrement acoustique en champ total permet d'accéder aux logs acoustiques classiques (lenteur, fréquence, atténuation) ainsi qu'aux logs de dispersion de mesure qui leur sont associés. Ces logs conduisent à des logs de paramètres mécaniques notamment au coefficient de Poisson. Dans le cas du puits étudié traversant une formation argilo-gréseuse, le log du coefficient de Poisson et le log de fréquence des ondes de Stoneley sont utilisés comme indicateur lithologique d'argilosité et de présence d'hydrocarbures (gaz). Après correction d'argilosité, les logs de lenteur en onde compression et de cisaillement sont utilisés en combinaison avec un log densité de type Gardner pour estimer les paramètres pétrophysiques de la formation (indices de porosité et de saturation en gaz). Les résultats obtenus sont comparés à ceux fournis par l'analyse de logs classiques (neutron, densité)

Demonstrating the need for chemical exposure characterisation in a microplate test system: Toxicity screening of sixteen pesticides on two marine microalgae

Pesticides used in viticulture create a potential risk for the aquatic environment due to drift during application, runoff and soil leaching. The toxicity of sixteen pesticides and one metabolite were evaluated on the growth of two marine microalgae, Tisochrysis lutea and Skeletonema marinoi, in 96-h exposure assays conducted in microplates. For each substance, concentrations of stock solutions were analytically measured and abiotic assays were performed to evaluate the chemical stability of pesticides in microplates. For two chemicals, microalgae exposures were run simultaneously in microplates and culture flasks to compare EC50 calculated from the two exposure systems. Results from chemical analyses demonstrated the low stability of hydrophobic pesticides (log KOW > 3). For such chemicals, EC50 values calculated using measured pesticide concentrations were two-fold lower than those first estimated using nominal concentrations. Photosystem II inhibitors were the most toxic herbicides, with EC50 values below 10 μg L−1 for diuron and around double this for isoproturon. Chlorpyrifos-methyl was the only insecticide to significantly affect the growth of T. lutea, with an EC50 around 400 μg L−1. All fungicides tested were significantly toxic to both species: strobilurins showed low overall toxicity, with EC50 values around 400 μg L−1, whereas quinoxyfen, and spiroxamine, showed high toxicity to both species, especially to T. lutea, with an EC50 below 1 μg L−1 measured for spiroxamine in culture flasks. This study highlights the need to perform chemical analyses for reliable toxicity assessment and discusses the advantages and disadvantages of using microplates as a toxicity screening tool

A workflow to integrate ecological monitoring data from different sources

International audiencePrograms and initiatives aiming to protect biodiversity and ecosystems have increased over the last decades in response to their decline. Most of these are based on monitoring data to quantitatively describe trends in biodiversity and ecosystems. The estimation of such trends, at large scales, requires the integration of numerous data from multiple monitoring sites. However, due to the high heterogeneity of data formats and the resulting lack of interoperability, the data integration remains sparsely used and synthetic analyses are often limited to a restricted part of the data available.Here we propose a workflow, comprising four main steps, from data gathering to quality control, to better integrate ecological monitoring data and to create a synthetic dataset that will make it possible to analyse larger sets of monitoring data, including unpublished data.The workflow was designed and applied in the production of the Status of Coral Reefs of the World: 2020 report, where more than two hundred individual datasets were integrated to assess the status and trends of hard coral cover at the global scale. The workflow was applied to two case studies and associated R codes, based on the experience acquired during the production of this report.The proposed workflow allows for the integration of datasets with different levels of taxonomic and spatial precision, with a high degree of reproducibility. It provides a conceptual and technical framework for the integration of ecological monitoring data, allowing for the estimation of temporal trends in biodiversity and ecosystems or to test ecological hypotheses at larger scales

Individual back-calculated size-at-age based on otoliths from Pacific coral reef fish species

International audienceAbstract Somatic growth is a critical biological trait for organismal, population, and ecosystem-level processes. Due to its direct link with energetic demands, growth also represents an important parameter to estimate energy and nutrient fluxes. For marine fishes, growth rate information is most frequently derived from sagittal otoliths, and most of the available data stems from studies on temperate species that are targeted by commercial fisheries. Although the analysis of otoliths is a powerful tool to estimate individual growth, the time-consuming nature of otolith processing is one barrier for collection of comprehensive datasets across multiple species. This is especially true for coral reef fishes, which are extremely diverse. Here, we provide back-calculated size-at-age estimates (including measures of uncertainty) based on sagittal otoliths from 710 individuals belonging to 45 coral reef fish species from French Polynesia. In addition, we provide Von Bertalanffy growth parameters which are useful to predict community level biomass production

A new impact panel to study bergy bit/ship collisions

A new design has been generated for an impact panel that is intended for use in a second bergy bit / ship collision field study. The design incorporates new technology to measure impact loads and pressure distribution at fine spatial resolution. The panel consists of 6 large sensing modules. Each module is a solid acrylic block with dimensions 1m x 1m x 0.46 m, giving the impact panel a total sensing area of 6 m\ub2. Each module sits on four flat-jack type load cells. All 6 modules are housed in a 3m x 2m rigid steel structure that is welded to the hull of the vessel at the bow center. The top surface of each module is covered with a new pressure-sensing mechano-optical technology capable of measuring pressure with an effective unit sensing area of about 1.3 cm x 1.3 cm. Data from the sensing modules are recorded by cameras operating at a capture rate of 250 images/s that are situated at the back end of each sensing module. A secondary means of measuring pressure at an array of locations on each module surface consists of strain gauges imbedded in the acrylic close to the impacting surface. The panel is intended for use within the next few years in a full-scale study of ship / bergy bit collisions with impact loads in the 0 ? 20 MN range.Peer reviewed: YesNRC publication: Ye

CDK4 phosphorylation status and rational use for combining CDK4/6 and BRAF/MEK inhibition in advanced thyroid carcinomas.

CDK4/6 inhibitors (CDK4/6i) have been established as standard treatment against advanced Estrogen Receptor-positive breast cancers. These drugs are being tested against several cancers, including in combinations with other therapies. We identified the T172-phosphorylation of CDK4 as the step determining its activity, retinoblastoma protein (RB) inactivation, cell cycle commitment and sensitivity to CDK4/6i. Poorly differentiated (PDTC) and anaplastic (ATC) thyroid carcinomas, the latter considered one of the most lethal human malignancies, represent major clinical challenges. Several molecular evidence suggest that CDK4/6i could be considered for treating these advanced thyroid cancers.info:eu-repo/semantics/publishe

Early development of the Southern Kerguelen Plateau (Indian Ocean) from shallow wide-angle ocean bottom seismometer and multichannel seismic reflection data

We examine the early geological history of the southern Kerguelen Plateau (Indian Ocean) using ocean bottom seismometer (OBS), multichannel seismic (MCS), and Ocean Drilling Program data. Velocity-depth models in the sedimentary Raggatt Basin are constrained by near-range OBS data (refractions and reflections, including multiples and converted shear waves) and migrated MCS data. The models elucidate the significance of Lower Cretaceous lava flows, Albian to Coniacian/Santonian terrestrial and terrigenous sediment, and Maastrichtian and Paleocene seismic sequences. The Albian/Aptian basaltic basement complex consists of an upper and a lower series. The upper series is characterized by average Vp S of 4.6–4.7 km/s, an upward increase of intercalated terrestrial sediment and altered flowtops, and a concomitant decrease in flow thickness; the lower series is marked by average Vp S of 5.3–5.5 km/s, and contains thicker flows and less sediment. A volcanic center in the Raggatt Basin shows relatively low Vp S (3.7–3.9 km/s for the upper series, 4.7–4.9 km/s for the lower series), and dipping reflections on the Raggatt Basin's flanks are also recorded as refractions. Terrestrial and terrigenous sediment of the Raggatt Basin, immediately overlying basement, is characterized by a seismic low-velocity layer with Vp S ranging from 2.2–2.9 km/s and a thickness of &gt;1100 m in the central basin. Nearby source regions (e.g., Banzare Bank and other elevated areas south of the basin) account for a terrestrial and terrigenous sediment volume of ?12,500 km3, deposited over ?20 m.y. The depocenter of the Raggatt Basin began shifting in Santonian to early Maastrichtian time, and concluded by early late Paleocene time. <br/