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Magnetotactic bacteria affiliated with diverse <i>Pseudomonadota</i> families biomineralize intracellular Ca-carbonate
No full textInternational audienceIntracellular calcium carbonate formation has long been associated with a single genus of giant Gammaproteobacteria, Achromatium. However, this biomineralization has recently received increasing attention after being observed in photosynthetic Cyanobacteriota and in two families of magnetotactic bacteria affiliated with the Alphaproteobacteria. In the latter group, bacteria form not only intracellular amorphous calcium carbonates into large inclusions that are refringent under the light microscope, but also intracellular ferrimagnetic crystals into organelles called magnetosomes. Here new observations suggest that magnetotactic bacteria previously identified in the sediments and water column of Lake Pavin (France) were only a small fraction of the diversity of bacteria producing intracellular amorphous calcium carbonates. To explore this diversity further, we conducted a comprehensive investigation of magnetotactic populations with refractive granules using a combination of environmental microbiology, genomic and mineralogy approaches on cells sorted by micromanipulation. Several species belonging to divergent genera of two Pseudomonadota classes were identified and characterized. Scanning transmission electron microscopy coupled with energy-dispersive X-ray spectrometry support that all these species indeed form intracellular amorphous calcium carbonates. Cryo soft X-ray tomography experiments conducted on ice-vitrified cells, enabled 3D investigation of inclusions volume, which was found to occupy 44-68% of the cell volume. Metabolic network modeling highlighted different metabolic abilities of Alpha-and Gammaproteobacteria, including methylotrophy and CO 2 fixation via the reverse Krebs cycle or the Calvin-Benson-Bassham cycle. Overall, this study strengthens a convergent evolution scenario for intracellular carbonatogenesis in Bacteria, and further supports that it is promoted by the fixation of CO 2 in anoxic environments.</div
Association between chronic long-term exposure to airborne dioxins and breast cancer
No full textInternational audienceBreast cancer is the most common type of cancer among women. Environmental pollutants, specifically those with endocrine disrupting properties like dioxins, may impact breast cancer development. Current epidemiological studies on the association between exposure to dioxins and the risk of breast cancer show inconsistent results. To address these uncertainties, our objective was to investigate the impact of airborne dioxin exposure on breast cancer risk within the E3N cohort, encompassing 5222 cases identified during the 1990–2011 follow-up and 5222 matched controls. Airborne dioxin exposure was assessed using a Geographic Information System-based metric considering residential proximity to dioxin emitting sources, their technical characteristics, exposure duration and wind direction. Additional analyses were performed using dioxin concentrations estimated by a chemistry transport model, CHIMERE. The results suggest a slightly increased risk between cumulative dioxin exposure at the residential address and overall breast cancer risk (adjusted odds ratio (OR) = 1.03, 95% confidence interval (CI): 0.99–1.07, for a one standard deviation (SD) increment among controls (14.47 log-μg-TEQ/m2). The associations remained consistent for sources within 3, 5, and 10 km, and when restricting exposure to dioxin emissions from household waste incinerators. Similar OR estimates (OR = 1.02, 95% CI: 0.97–1.07, for a one SD increment) were obtained using the CHIMERE model. The findings of this study suggest the possibility of an increased risk of breast cancer associated with long-term residential exposure to dioxins and emphasize the importance of efforts to mitigate air pollution exposure
Retrieval of benthic habitat abundance and bathymetry from hyperspectral data (DESIS) in shallow waters
No full textInternational audienceThe seabed mapping can be employed as a tool for the assessment of the impact of boat anchors on seagrass meadows. The hyperspectral sensor DESIS (DLR, Germany), having both a medium pixel size (30 m), a wide spectral range (400–1000 nm) and a spectral sampling interval of 2.55 nm. The goal of this study is to evaluate the performance of DESIS sensor for the retrieval of the bathymetry and the composition of benthic habitats in coastal shallow waters and to analyze the influence of the spectral sampling interval (2.55 or 10 nm) on the quality of the retrievals. The inversion of the DESIS-derived water reflectance is performed using a semi-analytical model. The performance of the retrieval of the bathymetry is validated using a well-proven bathymetric model developed by French navy (SHOM), namely Litto3D. The abundances of benthic species are compared with in-situ data that were acquired using a Go-Pro camera fixed on a Remoted Operated Vehicle. The bathymetry is retrieved from DESIS data with a root mean square error (RMSE) of 1.69 m for a seabed depth up to 10 m for a spectral sampling interval of 10 nm and increases up to 2.19 m for a spectral sampling interval of 2.55 nm as a result of an increased noise in the signal for such a better spectral sampling interval. The RMSE errors obtained when retrieving the proportion of benthic habitat species when the bottom depth is 10 m are 37% and 4%, respectively for a spectral sampling interval of 10 nm. The errors increase up to 46% and 20% for a spectral sampling interval of 2.55 nm. A pixel size of 30 m could be also a limitation to satisfactorily retrieve benthic composition and bathymetry. Overall, this study confirms the high interest and benefit of hyperspectral satellite sensors for improving knowledge of aquatic ecosystems in shallow waters
L’accès dérogatoire aux sources du droit et le contrôle de l’intégrité scientifique par des acteurs extra-universitaires
No full textInternational audienceNombreuses sont les entreprises de recherche sur les archives étatiques ou les jugements administratifs qui nécessitent de solliciter un accès dérogatoire. Ainsi, pour une demande d’accès à des archives ministérielles non librement communicables pour des raisons telles que la protection du secret médical ou du secret de la défense nationale, le service des archives nationales ainsi que le ministère concerné par la demande apprécieront les garanties que présente le chercheur. Ce dernier devra alors produire un discours démontrant, notamment, son intégrité scientifique, à l’aide d’attestations de pairs ou d’articles publiés reposant sur des données similaires. Une fois l’accès à ces sources obtenu, l’utilisation des données par le chercheur se trouve également encadrée par les instances ayant délivré l’accès. Le Conseil d’État a, par exemple, fait évoluer les conditions d’accès à ses propres bases de données en 2018. Depuis, le chercheur désireux d’étudier les jugements rendus par les tribunaux administratifs doit s’engager à, entre autres, prévenir le Conseil d’État quinze jours avant toute diffusion publique des travaux issus des données collectées. Qu’il s’agisse de l’accès aux archives ou à la jurisprudence administrative, l’intégrité scientifique du demandeur n’est jamais explicitement mentionnée dans les procédures, mais c’est pourtant elle qui est visée pour autoriser l’accès ou encadrer l’usage des données collectées. Ainsi la présente contribution vise-t-elle à interroger le contrôle de l’intégrité scientifique qui résulte des limitations à l’accès aux sources du droit
Natural and anthropogenic drivers of the water table dynamics in a riparian fen peatland
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What Will the European Climate Look Like in the Future? A Climate Analog Analysis Accounting for Dependencies Between Variables
No full textInternational audienceIncreasing the awareness of society about climate change by using a simplified way for the explanation of its impacts might be one of the key elements to adaptation and mitigation of its possible effects. This study investigates climate analogs, which allow the possibility to find, today, a place on land where climatic conditions are similar to those that a specific area will face in the future. The grid-based calculation of analogs over the selected European domain was carried out using a newly proposed distance between multivariate distributions, the Wasserstein distance, that has never been used so far for climate analog calculations. By working on the whole multivariate distributions, the Wasserstein distance allows us to account for dependencies between the variables of interest and for the shape of their distribution. Its features are compared with the Euclidean and the Mahalanobis distances, which are the most used methods up to now. Multi-model climate analogs analysis is achieved between the reference period 1981-2010 and three future periods 2011-2040, 2041-2070, and 2071-2100, for seasonal temperatures (mean, min, and max) and precipitation, from five different climate models and three different socio-economic scenarios. The agreement between climate models in the location and degree of similarity of the best analogs decreases as warming intensifies and/or as time approaches the end of the century. As the climate warms, the similarity between future and current climatic conditions gradually decreases and the spatial (geographical) distance between a location and its best analog increases.</div
Vanadium and Iron substituted polyoxotungstate iodonium and tetrabutylammonium salts for visible light Free Radical Polymerization
No full textInternational audienceA series of diphenyliodonium and tetrabutylammonium salts of vanadium (+V) and iron (+III) mono and disubstituted polyoxotungstates was designed and tested as visible light photoinitiators for the free radical polymerization of acrylates or the cationic polymerization of epoxides. Interestingly, these polyoxotungstates could act as efficient photosensitizers for Type I or Type II photoinitiators (TPO-L, ITX), enabling to get excellent monomer conversions upon excitation at 405 nm
The origin of ferruginous concretions on the Sunda Shelf (SE Asia) and its environmental implications
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Enabling secure data-driven applications: an approach to personal data management using trusted execution environments
No full textInternational audienceIn a rapidly evolving landscape, Personal Data Management Systems (PDMS) provide individuals with the necessary tools to collect, manage and share their personal data. At the same time, the emergence of Trusted Execution Environments (TEEs) offers a way to address the critical challenge of securing user data while fostering a thriving ecosystem of data-driven applications. In this paper, we employ a PDMS architecture leveraging TEEs as a fundamental security foundation. Unlike conventional approaches, our architecture enables extensible data processing by integrating user-defined functions (UDFs), even from untrusted sources. Our focus is on UDFs involving potentially large sets of personal database objects, with a novel proposal to mitigate the potential risk of data leakage. We introduce security building blocks to impose an upper bound on data leakage and investigate the efficiency of several execution strategies considering different scenarios relevant to personal data management. We validate the proposed solutions through an implementation using Intel SGX on real datasets, demonstrating its effectiveness in achieving secure and efficient computations in diverse environments.</div
