Production de contenus sur Instagram autour d’œuvres des collections muséales : de la tension entre images iconiques et images inédites

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Diffusive gradient in thin film for ultra-trace methylmercury measurements in the coastal and open sea

International audienceMonomethylmercury (MMHg) is a potent neurotoxin causing neurodevelopmental delays and cardiovascular and immunological issues. Human exposure primarily occurs through seafood consumption due to MMHg bioaccumulation and biomagnification from seawater into marine organisms. Determining MMHg in seawater at ultratrace concentrations poses logistical and analytical challenges. Diffusive Gradient in Thin-film (DGT) samplers represent a promising solution, which captures time-averaged concentrations by preconcentrating in situ MMHg over a defined exposure time. DGT manufactured with 3-mercaptopropyl-functionalized silica (3MFS) in agarose and polyacrylamide gels were tested and compared for the determination of MMHg present in open ocean and coastal waters. Different elution methods using acidic thiourea were tested to reach precise, accurate and quantitative elution of MMHg from the binding gel. We found that polyacrylamide-3MFS binding gels display a higher elution efficiency (94 ± 3 %), precision and better handling compared to agarose-3MFS gels (41 ± 6 %). A unique mooring line installed in the South Western Tropical Pacific Ocean, provided monthly DGT-MMHg concentrations over a year showing potential seasonal differences in MMHg concentrations ranging between 18 and 106 fM. DGT were also deployed in shallow Peruvian coastal waters, exhibiting higher MMHg concentrations (170 ± 97, n = 26) with typical benthopelagic gradients. DGT-MMHg concentrations were in good agreement with discrete water samples analyzed by reference methods using isotope dilution. DGTs offer complementary advantages over oceanographic cruises, notably in situ preconcentration, low blanks, minimal logistical requirements and cost-effectiveness. DGTs represent a valuable tool for studying the marine MMHg cycle for evaluating the implementation of the Minamata Convention.</div

Tensor Decompositions for Signal Processing: Theory, Advances, and Applications

International audienceIn the era of big data, rapid advancements in technology and data collection methods have led to the generation and accessibility of vast amounts of multi-modal, high-dimensional data across a diverse range of disciplines. Tensor methods have emerged as essential tools in signal processing, providing powerful frameworks to model and analyze such complex data effectively. This survey offers a comprehensive overview of tensor factorization techniques and their applications in key areas. We explore their role in remote sensing, focusing on tensor-based methods for analyzing hyperspectral and multispectral images, tackling challenges such as recovering super-resolution images and addressing spectral unmixing. In wireless communication, we examine tensor methods used for signal modulation in unsourced massive random access communication, which achieve strong performance in multi-antenna channel and signal modeling. We also discuss tensor applications in network compression, where they reduce the computational demands of deep neural networks, making them more feasible for edge devices. Additionally, we highlight the use of tensor methods in high-dimensional missing data completion problems, showcasing their versatility across various domains. Furthermore, we explore applications in image analysis and computer vision, where tensors are effectively utilized for motion and object tracking, 3D modeling, analysis of satellite imaging, and medical imaging. By bridging theoretical advancements with practical applications, this survey aims to guide researchers in leveraging tensor methods to tackle emerging challenges in signal processing

Micro-scale investigation of the role of fabric on internal stability of gap-graded soils

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Decoding lactate kinetics in septic shock: From flow to metabolism

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Molecular dynamics study on the coupled effects of size and pre-existing oxide layer on the compressive mechanical properties of copper nanowires

International audienceCopper nanowires generally exhibit a native oxide shell layer, which can significantly impact their performance and reliability, especially in nanoelectronics applications. Using molecular dynamics simulations with the variable charge ReaxFF potential, we systematically examine the effects of preexisting oxide layers on the mechanical properties and deformation mechanisms of [001]-oriented Cu nanowires with varying diameters at room temperature. Our findings reveal a size-dependent influence of the native oxide layer on the mechanical behavior. Specifically, the formation of an oxide shell (CuxOy) around the Cu core reduces the activation barrier for defect nucleation, reducing yield properties and, thereby, weakening the nanowires. This effect is more pronounced in smaller samples due to the intensified interaction between the metallic core and the oxide shell. Additionally, while the strength, elastic modulus, and yield stress increase with the diameter of pristine and oxidized specimens, pristine nanowires consistently exhibit superior mechanical properties when compared to their oxidized counterparts. The degradation in mechanical performance primarily stems from the early onset of plasticity initiated at the oxidized surface. These findings emphasize the detrimental impact of native oxide layers on the mechanical behavior of Cu nanowires and highlight the critical role played by size upon the mechanical properties of nano-oxidized metal samples. This work provides valuable insights into tailoring the mechanical properties of Cu nanowires, contributing to the optimization of their performance in both nanoelectronics and mechanical applications.</div

High alpine preglacial caves modified by glacial processes and late condensationcorrosion in the Scerscen Valley (Valmalenco, Western Alps, Italy)

International audienceThe Scerscen Valley (western Italian Alps) is home to caves at an altitude of around 2600 m, opening close to the Speleogenesis edge of a glacier. The aim of the research as part of a multi-disciplinary project was to reconstruct the evolution Alpine Cosmogenic GeomorphologyHydrogeologyglaciersburial dating of cosmonucleide some the of caves the related most burial recent to dating, the processes, geological recorded such and morphology paleoenvironmental as condensation-corrosion and micrometeorology, evolution and of sediment the carried area deposition. and out mineralogical to evaluate We the performed identifirole of cation by XRD, and hydrogeology using dye tracing and physical and chemical analyses. The cosmonucleide dating of quartz pebbles showed that the Veronica Cave is the oldest, with deposits dated at 1.3 ± 0.4 Ma, and possibly even older. It certainly formed at a much lower altitude (approx. 1300 m a.s.l. or lower) during the Alpine uplift. The Morgana and Marsooi caves, given the smaller volume of their phreatic conduits (1/3 of Veronica), are possibly more recent, formed during interglacials and evolved close to a glacial body. The caves initiated in dolomitic marble under the influence of sulfuric acid speleogenesis (SAS) due to pyrite oxidation. The conduits were then enlarged dramatically under phreatic conditions. The caves have evolved since their preglacial formation, with phases of filling by fluvio-glacial sediments and unclogging. Water tracing and physico-chemical analysis attest to a well-karstified aquifer, with rapid water circulation (&gt;20 m/h) and low temperatures (~2 °C), draining towards the main spring, "La Prediletta", located at the foot of the dolomitic marbles. Microclimatic records (cave temperature and humidity) show seasonal cycles of condensation and evaporation, influenced by air exchanges with the outside atmosphere. These processes contributed to the formation of secondary minerals by evaporation (gypsum, hydromagnesite…) and, above all, to the significant enlargement of passages by the retreat of walls with characteristic morphologies (facets and grooved walls). The Scerscen caves bear witness to a long geological and climatic history, from their formation before the Mid-Pleistocene ice ages to their present-day evolution. They offer valuable insights into karst processes in the high mountains, and interactions between glaciers and aquifers

Platinum and Rare Earth Elements distribution in costal sediments from French western Mediterranean Sea

International audienceThis study presents the first assessment of Technological Critical Elements (TCE), specifically platinum (Pt) and rare earth elements (REE), in coastal sediments along the French western Mediterranean Sea. These trace elements, increasingly used in advanced technologies, raise particular concerns due to their potential environmental impact. Surface sediment samples were collected from 21 stations along the French Mediterranean coast (from Spain border to Italy including Corsica Island) to evaluate TCE concentrations and identify potential sources. Most of the REE concentrations fell within expected natural levels and were mainly influenced by the geological characteristics of local watersheds, indicating a dominant geogenic origin. When normalized to European Shale, REE distribution patterns exhibited convex shapes, typical of coastal environments. In contrast, localized Pt enrichment were detected at specific sites, particularly in port areas, which could be linked to anthropogenic emissions from vehicular catalytic converters. These results highlight platinum as a relevant emerging contaminant in urban coastal environments. However, unexpected REE and Pt concentrations at the mouth of the Hérault river call for further investigation. This study highlights the importance of integrating geological background and anthropogenic pressures in coastal sediment quality assessments and supports the inclusion of TCE in long -term environmental monitoring programs in the Mediterranean Sea

Acquisition and Management of Aquatic Resources in Fos-sur Mer, Provence, France (11th–14th century AD). Archaeoichthyological Results

International audienceFew studies have focused on marine resources in the medieval and modern western Mediterranean from an archaeoichthyological perspective. This paper presents preliminary results from one of the five sites that are part of a larger PhD project on the consumption and acquisition of aquatic resources in Provence (6th–17th cent. AD). This study also integrates some of the results obtained within the framework of the inter-team AMORCE project Icht’isomed2, financed by the Institute of Mediterranean Archaeology ARKAIA

Improving visibility for knowledge holders in ethnobiological and ethnopharmacological publications

International audienceEthnopharmacological relevance: Ethnopharmacology and ethnobiology largely focus on the study of traditional knowledge related to medicinal and other uses of plants, animals or minerals. Despite decades of political advocacy, ethnopharmacological and ethnobiological information is still sometimes published without proper attribution of the cultural identities and affiliations of the communities that shared it.Aim of the study: Identify key guidelines to ensure the proper attribution of ethnobiological and ethnopharmacological knowledge recorded in scientific publications to the communities who provided it.Material and methods: This article is based on extensive group discussions that started at a workshop entitled “A worldwide database of local uses of biodiversity: Why? For whom? And how?” (18th Congress of the International Society of Ethnobiology in Marrakech, Morocco, May 15–19, 2024), and was attended by around 50 participants. The guidelines were developed through an iterative revision process.Results: We propose practical guidelines to improve the attribution and thus, visibility, of communities whose knowledge contributes to ethnobiological and ethnopharmacological publications. Recognising individual knowledge holders remains a critical topic on its own right.Conclusion: Transparent and consistent reporting of the provenance of place-based ancestral knowledge from communities is essential for advancing the objectives of the Nagoya Protocol, the Treaty on Intellectual Property, Genetic Resources and Associated Traditional Knowledge, and for strengthening academic inquir