HAL-Université de Bretagne Occidentale
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Le visage de la personne dans le miroir du droit. Exégèse de l’article 16 du Code civil
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Étude de l’impact des propriétés physico-chimiques de films de polymères hydrophobes sur leur colonisation par des micro-organismes
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Oral language profiles and associated factors in children after neonatal arterial ischaemic stroke.
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Role of atmospheric and oceanographic frequency variability on surface Marine Heatwaves in the Northern Humboldt Current System
No full textInternational audienceIn this study, we investigated the role of atmospheric and oceanographic variability in shaping surface Marine Heatwaves (MHWs) in the Northern Humboldt Current System (NHCS) over the last two decades. Through a series of pluriannual hydrodynamic model simulations, we highlighted the importance of considering at least high-frequency atmospheric variability to accurately reproduce the observed MHW characteristics. On the contrary, when synoptic atmosphere variability is removed, the simulation results in fewer, longer, less frequent, less intense, and less severe MHWs. As a consequence, simulations forced with low-frequency data are only able to partially reproduce persistent MHWs. Additionally, using the heat balance analysis, it is shown that at the north, short-lived events are primarily driven by advective causes, while persistent events show an equal contribution between advection and heat fluxes. In the south, changes in heat fluxes are crucial in forming MHWs. During the dissipation phase of MHWs, cooling is dominated by advective processes, mainly coastal upwelling, in both coastal regions. Overall, these findings indicate a reduced dependence on high-frequency oceanic forcing and highlight the need to consider the atmospheric variability in regional downscaling of global climate model simulations to capture almost the full range of MHW events in the NHCS
La marine de la Révolution en Bretagne : une éclaircie dans la tempête ?
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MoRE: Multi-Oracle Reward Evolution for Automated Reward Shaping in Reinforcement Learning
No full textInternational audienceAutomated reward design remains a critical bottleneck in reinforcement learning (RL): handcrafted reward functions require specialized expertise, while singlemodel LLM approaches suffer from hallucinations and inconsistent outputs. We introduce MoRE (Multi-Oracle Reward Evolution), a novel framework that leverages an ensemble of large language models, each acting as a distinct oracle to generate and iteratively refine whitebox reward functions. Identical prompts are issued to multiple LLM oracles, yielding a diverse candidate pool that is evaluated via GPU-accelerated Proximal Policy Optimization and evolved through incontext reward reflection. Across 29 tasks in the Isaac Gym and Dexterity benchmarks, MoRE matches or surpasses its predecessor (Eureka), expert-engineered rewards, and sparse baselines, achieving the highest success rates in 24 of 29 environments. An ablation study confirms that consulting multiple oracles, rather than relying on any single model, is essential for robust, highdimensional reward design. MoRE substantially reduces human effort by automating reward function generation and tuning, mitigates hallucination risk by relying on several LLMs rather than one, and delivers state-of-the-art performance on complex RL control problems
ICU-acquired infections and thrombo-embolic events in critically ill patients receiving platelet transfusion: a prospective multicenter observational study.
No full textInternational audienceBackground: Platelet transfusion is relatively common in patients hospitalized in intensive care units (ICU). Both ICU-acquired infections and thromboembolic events have been reported after platelet transfusion. We sought to explore risk-factors of these complications.Materials and methods: We conducted a ancillary analysis of a multicenter prospective observational study including critically ill patients who received at least one platelet transfusion in one of the 9 participating ICUs. Patients' characteristics were compared according to the occurrence of post platelet transfusion ICU-acquired infections (blood stream infections and ventilator-associated pneumonia) and thromboembolic events. Factors associated with those outcomes were assessed by univariable and multivariable Fine and Gray regression.Results: Of the 310 included patients, 64 patients (20.6%) and 14 patients (4.5%) experienced at least one ICU-acquired infection and a thromboembolic event after platelet transfusion, respectively. Fifty patients (78.1%) developed blood stream infection (BSI), 32 (50%) experienced ventilator associated pneumonia (VAP) and 18 (28.1%) had both VAP and BSI. Independent risk factors for post platelet transfusion ICU-acquired infection included a platelet count at ICU admission <109/L (protective) (subdistribution Harard Ratio (sHR) 0.52 95% CI [0.31-0.89] p=0.016), multiple platelet transfusion prior to infection occurrence (sHR 2.15 [1.25-3.71] p=0.005) and a Simplified Acute Physiology Score (SAPS) II>50 (sHR 3.67 [2.16-6.25] p<0.001). While, the unique variable independently associated with thrombotic event occurring after platelet transfusion in adjusted Fine-Gray regression was a SAPS II >50 (sHR 4.27 [1.18-15.39] p=0.027).Discussion: In this prospective multicenter study, the risk of hospital-acquired infection after platelet transfusion increased in patients receiving multiple platelet transfusions and with patient severity at ICU admission
