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Multi-Partner project: dAIEDGE - A network of excellence for distributed, trustworthy, efficient and scalable AI at the edge
No full textInternational audienceThe dAIEDGE Network of Excellence (NoE) seeks to strengthen and support the development of a dynamic European cutting-edge Artificial intelligence (AI) ecosystem under the umbrella of the European Lighthouse for AI, and to sustain the development of advanced AI. dAIEDGE fosters the exchange of ideas, concepts, and trends on cutting-edge next generation AI, creating links between ecosystem actors to help both the European Commission (EC) and the European Union (EU) and the peripheral AI constituency identify strategies for future developments in Europe. Our main objective is to advance Europe's innovation and technology base by developing a comprehensive policy and governance approach to AI in order for the EU to become a world leader in innovation in the data economy and its application
Robust a posteriori estimation of probit-lognormal seismic fragility curves via sequential design of experiments and constrained reference prior
No full textInternational audienceA seismic fragility curve expresses the probability of failure of a structure conditional to an intensity measure (IM) derived from seismic signals. When only limited data is available, the practitioner often refers to the probit-lognormal model coupled with maximum likelihood estimation (MLE) to obtain estimates of these curves. This means that only a binary indicator of the state (BIS) of the structure is known, namely a failure or non-failure state indicator, when it is subjected to a seismic signal with an intensity measure IM. In this context, the objective of this work is to propose a method for optimally estimating such curves by obtaining the most precise estimate possible with the minimum of data. The novelty of our work is twofold. First, we present and show how to mitigate the likelihood degeneracy problem which is ubiquitous with small data sets and hampers frequentist approaches such as MLE. Second, we propose a novel strategy for sequential design of experiments (DoE) that selects seismic signals from a large database of synthetic or real signals via their IM values, to be applied to structures to evaluate the corresponding BISs. This strategy relies on a criterion based on information theory in a Bayesian framework. It therefore aims to sequentially designate the IM value such that the pair (IM, BIS) has on average, with respect to the BIS of the structure, the greatest impact on the posterior distribution of the fragility curve. The methodology is applied to a case study from the nuclear industry. The results demonstrate its ability to efficiently and robustly estimate the fragility curve, and to avoid degeneracy even with a limited amount of data, i.e., less than 100. Furthermore, we demonstrate that the estimates quickly reach the model bias induced by the probit-lognormal modeling. Eventually, two criteria are suggested to help the user stop the DoE algorithm
Measurement of the Higgs boson total decay width using the H WW e decay channel in proton-proton collisions at = 13 TeV
No full textInternational audienceThe Higgs boson (H) decay width is determined from the ratio of off- and on-shell production of H WW e using proton-proton collision data corresponding to an integrated luminosity of 138 fb collected at = 13 TeV by the CMS experiment at the LHC. The off-shell signal strength is measured as = 1.2. The Higgs boson total decay width is = 3.9 MeV, in agreement with the standard model prediction. The uncertainty in this result represents a factor of three improvement over the previous CMS result in this decay channel
Fabrication of Centimeter‐Scale MoWS 2 ‐Based High Performing Solar Cells
No full textInternational audienceThe growing demand for efficient, scalable, and lightweight photovoltaic (PV) technologies has intensified interest in WS 2 and MoS 2 ‐based devices. Despite notable advances, achieving simultaneously high performance and long‐term operational stability remains a key barrier to broader adoption. Here, we address this challenge by fabricating p–n heterojunction solar cells through a single‐step chemical vapor deposition process that directly deposits WS 2 , MoS 2 , and their alloy MoWS 2 onto p‐type silicon substrates. The MoWS 2 alloy exhibits a reduced bandgap and enhanced optoelectronic properties, which translate into substantially improved PV output and device robustness. The MoWS 2 ‐based solar cell achieves a power conversion efficiency of 5.8%, outperforming the WS 2 and MoS 2 counterparts, which reach 1.12% and 3.6%, respectively. In addition, MoWS 2 displays markedly enhanced light‐harvesting capability, with an external quantum efficiency of 80%, compared to 30% for WS 2 and 50% for MoS 2 . Stability assessments further demonstrate that MoWS 2 retains its performance over a 30‐day test period, confirming its superior long‐term durability. By establishing the viability of MoWS 2 as a high‐potential photoactive material for lightweight PVs, this work sets the stage for future research and paves the way toward practical implementation of alloy‐engineered 2D semiconductor solar technologies
Probing electroweak pair production of heavy neutral leptons with displaced vertices at the LHC
No full textInternational audienceWe study the sensitivity of displaced vertex searches at the LHC to heavy neutral leptons (also known as sterile neutrinos) that are produced in pairs with an electroweak-size cross section. We work within the context of a supersymmetric model in which the sterile neutrino is produced along with Standard Model particles in higgsino decays. By making use of model-independent reconstruction efficiencies provided by the ATLAS collaboration in their search for displaced vertices with multiple jets, we obtain constraints on this model from fb of data collected by ATLAS during the LHC Run~2, and assess the discovery reach of Run~3 and of the high-luminosity LHC (HL-LHC). Depending on the higgsino mass parameter, sterile neutrino masses between and and active-sterile neutrino mixings in the range can be excluded. At the HL-LHC, discovery-level significances could be reached for sterile neutrinos masses up to and values of down to . Finally, moving away from the supersymmetric scenario, we study to which extent these results can be generalized to a broader class of models in which the sterile neutrinos are produced in the decays of heavier particles that are themselves pair-produced with an electroweak-size cross section
Thermal modelling of the discharge of a 180 kW·h latent thermal energy storage demonstrator
No full textInternational audienceThis paper presents the validation of a numerical model against experimental data for the discharge of a latent thermal energy storage. The experimental data come from the experimental characterization of 180 kW·h phase change material storage demonstrator installed in a substation of the Grenoble district heating network. The heat transfer fluid used is water and the phase change material is RT70HC. The numerical model has been presented and validated for different charging cases in a previous paper. This paper focus on the modelling of the phase-change during discharges, as the RT70HC has two solidification peaks. The model is a 1.5D model, developed in the DYMOLA software, with a 1D homogeneous approach for the heat transfer fluid combined with a 1.5D approach for the phase change material. The model with two solidification peaks reproduces the total energy unloaded during a discharge with an accuracy of 98.3 %, a root-mean-square error of 3 kW on outlet power and 1.6 °C for storage outlet temperature. These results are slightly better than a model with one peak of solidification (accuracy of 98 %, root-mean-square error of 3.22 kW on outlet power and 1.7 °C for storage outlet temperature). The conclusion is that consideration of the two peaks in this case is not mandatory
Quantitative mapping of methionine sensitivity to oxidation in the copper-bound PcuC chaperone
No full textCopper is typically coordinated by histidine, cysteine, or methionine in proteins, and these residues are particularly sensitive to oxidation. However, it remains unclear whether copper-coordinating residues are more prone to oxidation than non-coordinating ones, and how their susceptibility changes between the apo and copper-bound states. The copper chaperone PcuC, important for cytochrome c oxidase assembly in bacteria, contains a canonical binding site composed of two histidines and two methionines (H51x n M63x 22 H86xM88), as well as a disordered C-terminal extension enriched in methionine and histidine. To quantify methionine oxidation sensitivity in both apo- and Cu-bound PcuC, we used a methionine-specific oxaziridine probe combined with mass spectrometry and compared labeling patterns to those generated by 18 O-labeled hydrogen peroxide. We show that methionine residues display distinct oxidation sensitivities in the apoprotein, and that the oxaziridine reacts similarly to H 2 18 O 2 . Importantly, this probe enables quantification of methionine oxidation independently of hydroxyl radicals generated by copper-driven Fenton chemistry, which lacks residue specificity. In the copper-bound form, Cu binding strongly alters methionine reactivity, with a marked increase in oxidation of the coordinating Met63 and Met88. Structural analysis revealed that two copper ions occupy the canonical site, while the C-terminal extension does not contribute to coordination. Comparison of structural features and oxidation values showed that methionine sensitivity correlates with solvent exposure in the folded domain, but with local positive charge in the disordered region. These findings demonstrate that copper coordination modulates methionine oxidation, and that oxaziridine-based probes provide powerful tools for mapping oxidation sensitivity in (metallo)proteins
Holocene climatic changes in the Kerguelen archipelago (South Indian Ocean) based on marine and lacustrine palaeoclimatic archives
No full textInternational audienceClimatic variability in the Southern Hemisphere is largely controlled by the latitudinal position of the Southern Hemisphere Westerly Winds (SHW), whose migration influences precipitation, temperature, and Antarctic upwelling. This study presents the results of analyses of two lacustrine sediment cores from Lake Armor, located on the subantarctic Kerguelen Islands (49 • 15′S, 69 • 10′E), within the SHW belt. Lipid biomarkers (Glycerol Dialkyl Glycerol Tetraethers, n-alkanes, and their hydrogen isotopes) were used to reconstruct mean annual air temperature above freezing (MAF) and humidity conditions. These records are compared with a high-resolution diatom-based summer sea surface temperature (SST) reconstruction from marine core MD11-3353, situated 150 km southwest of Lake Armor. In the late glacial and Early Holocene, our results reveal a period of warm air temperature, comparable to current values and very warm sea surface temperature, 5°C above the current values. Around 9000 cal a BP, an abrupt transition occurred, marked by a cooling of 5°C in SST and 1.5°C in MAF, interpreted as a northward migration of the SHW and associated oceanic fronts. The Mid-to-Late Holocene period is characterized by pronounced MAF variability, including a notably warm interval between 3000 and 2000 cal a BP, when n-alkane dD suggests the prevalence of wetter conditions. Since ~250 cal a BP, a southward migration of the SHW has produced a 2.5°C rise in MAF. Our findings are overall consistent with previous studies from the Indian Ocean, but permit us to go a step further as by comparing SSTs and air temperatures. This suggests that SST is not a reliable predictor of air temperature on the Kerguelen Islands, particularly during the Early Holocene. We hence argue that Kerguelen air temperature is predominantly controlled by the position of westerly winds, as an indicator of reorganisations in air mass trajectories
Dust deposition on plasma-facing substrates extracted from the WEST Tokamak
No full textInternational audienceDust particles deposited during the first phase of operation of the WEST tokamak were collected and analyzed from substrates positioned at four distinct poloidal locations along the inner wall. Among various particle types composed of materials present in the vacuum vessel, previously unreported tungsten molten splashes exhibiting highly distinctive "stethoscope-like" morphologies were discovered. These unusual tungsten particles were found in large numbers exclusively on substrates located closest to the lower divertor. They display a well-defined log-normal size distribution, with average lengths ranging from 0.75 to 1.5 µm, and a clear angular alignment pointing predominantly away from the divertor. This directional distribution provides compelling evidence that they were ejected from the lower divertor region. Additionally, more conventional tungsten spheroidal particles were identified across all four poloidal positions. These spheroids were most abundant near the divertor and exhibited progressively more elongated shapes and less distinct alignment patterns with increasing distance, suggesting a common origin but different transport histories. Their size distributions are also lognormal, with average diameters between 100 and 200 nm. The characteristics of both particle types (distribution, size scaling, and directionality) suggest a common origin in molten tungsten droplets expelled from the lower divertor, most likely as a result of arcing events.</div
