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Interplay between lithium intercalation and plating during fast-charging of lithium-ion batteries investigated by operando NMR spectroscopy
No full textInternational audienceDuring fast charging, metallic lithium can form on the negative graphite electrode, compromising both cycle life and safety. After deposition, plated lithium can re-intercalate within graphite, be disconnected or chemically oxidized. To better understand these reactions and their kinetics, operando measurements on cells with electrochemical performances close to commercial ones are essential. Herein, a dedicated pouch-cell design is developed to follow the dynamic of lithium using 7Li nuclear magnetic resonance (NMR) spectroscopy. These developments provide 7Li NMR spectra every 6 min leading to a good temporal resolution. The dynamics of lithium is investigated for various charging scenarios and temperatures within NMC 811/graphite pouch cells with industry-standard electrodes. Introduction of an original method allows assessing the mass of plated lithium formed in operando mode, offering insights on the competition between graphite lithiation, plating, and reintercalation processes. Interestingly, the lithium deposition occurs mainly during the constant-current step and early stage of the constant-voltage (CV) step, and lithium reintercalation, oxidation, or disconnection during the subsequent CV hold, highlighting the interest of reducing the current during fast-charge scenario. Comparison with three-electrode monolayer pouch cells provides an onset of plating located between −100 and –150 mV versus Li
Switching characterization of SmartSiCTM semiconductor devices under temperature and comparison to equivalent devices in monocrystalline SiC substrate.
No full textInternational audienceThis article deals with the use of SmartSiCTM devices in power converters. Benefits of these substrates on the on-state resistance of the devices have been addressed in the literature. However, the impact on the switching behavior of the devices is not well studied. This paper compares the switching waveforms of several diode structures made on both monocristalline SiC substrates and SmartSiCTM substrates and shows that their switching characteristics are equivalent. Combining the decrease of the on-state resistance and the unchanged switching characteristics, these results show the benefits of the SmartSiCTM substrates to decrease the global semiconductor losses in power converters
How does a multifaceted intervention affect vaccination rates? Identifying profiles of healthcare workers hesitant about seasonal flu vaccination
No full textInternational audienceAim This study investigated the effect of a multifaceted intervention on fu vaccination rates among French healthcare workers (HCWs) and the characteristics of HCWs who were hesitant to vaccinate.Subject and methods HCWs (N = 983, Mage = 40.65, SD = 11.42) participated in a four-arm randomized controlled trial. The first group watched an informative video on vaccination (n = 286), the second group completed a survey on anticipated regret and the planning technique (n = 221), and the third group underwent the complete intervention (i.e., the video, anticipated regret, and planning technique; n = 253); the fourth group was the control group (n = 223). Three months later, they were sent a survey to measure their vaccination intention and behavior. The primary outcome was the vaccination rate, while the secondary outcome was the vaccination intention score.Results Altogether, 137 HCWs were analyzed. No significant effect of the intervention on the vaccination rate (p = .67, pseudo-R2 = .008) or vaccination intention (p = .85, n2p = .003, 95% CI [.000, .01]) among HCWs was observed. Additionally, factors such as attitude, self-efficacy, outcome expectations, and risk perception signifcantly infuenced T1 and T2 vaccination. HCWs with a higher socioeconomic status (SES) were more likely to be vaccinated than those with a lower or middle SES. No adverse events were reported.Conclusion Vaccination behavior raises questions about the efficacy of the planning technique, which appears to be more effective for HCWs with a high SES. Tailored, multi-intervention approaches seem necessary
Evidence accumulation in the pre-supplementary motor area and insula drives confidence and changes of mind
No full textInternational audienceEvidence accumulation is a powerful mechanism to explain the temporal dynamics of decisions, as well as their metacognitive components such as confidence judgments and changes of mind. However, it is still unclear how and where in the brain evidence accumulation leads to these two metacognitive components. We report intracranial high-gamma activity in patients with epilepsy recorded while they perform a visual discrimination task and estimate their confidence level. Our results indicate an anatomical overlap between the neural correlates of evidence accumulation, confidence, and changes of mind in the pre-supplementary motor area, as well as in the orbitofrontal, inferior frontal, and insular cortices. Behavioural and electrophysiological results are reproduced with a post-decisional evidence accumulation model, and the temporal dynamics of decision-making is characterized with mouse-tracking and intracranial electrophysiology. We conclude that confidence and changes of mind result from evidence accumulation, instantiated before the decision in the pre-supplementary motor area, and after the decision in the insula
Recherche de violation de l'invariance de Lorentz avec le Large-Sized Telescope de CTAO
No full textInternational audienceThe fast variability of very-high energy (VHE) sources such as pulsars, gamma rays bursts (GRBs) or flares of active galactic nuclei (AGN) can be used to detect or constrain Lorentz invariance violation (LIV) by measuring lags in the arrival time of VHE photons. However, an important source of uncertainty arises from processes within the source that may induce intrinsic photon delays. Combining observations of different sources allows us to probe higher energy scales when LIV effects become relevant as well as to distinguish LIV-induced lags from intrinsic effects. We present the results of a standardized analysis performed on all AGN observations carried out by the first Large-Sized Telescope (LST-1) of CTAO. This analysis includes a general search of intra-night variability in archive observing nights that show significant excesses for the target candidates. The observing nights selected for LIV searches are then combined together to extract limits to the characteristic energies at which the LIV effect is expected to be significant. Finally, similar analysis have been performed on relevant data from other major imaging atmospheric Cherenkov telescopes, H.E.S.S., MAGIC and VERITAS, in order to combine all the data sets to extract combined limits that constrain one of the LIV effects
Recovery of Fatigue, Cardiorespiratory Fitness, and Neuromuscular Function in Covid-19 ICU Patients: A 6-Month Follow-Up Study
No full textInternational audienceABSTRACT Purpose Although most patients recover well from Covid-19 infection, this may not be the case of those who experienced severe dysfunction after being admitted to intensive care unit (ICU). This study aimed to assess the recovery of patients who experienced severe multiple dysfunctions after being admitted to intensive care unit (ICU) for Covid-19 infection. Methods Forty-seven patients hospitalized and mechanically ventilated in ICU for SARS-CoV-2 infection underwent evaluations at 4-8 weeks (T1) and 6 months (T2) post ICU discharge. Evaluations included questionnaires, lung function tests, incremental cardiopulmonary exercise testing, and neuromuscular function tests. Results From T1 to T2, the percentage of patients classified as fatigued decreased from 56% to 21% whereas forced vital capacity and the forced expiratory volume in one second increased by 13% and 8% (p < 0.05) to reach 93% and 95% of predicted values at T2, respectively. Peak work rate also increased from 97 to 135 W (+35 ± 32%, p < 0.001). Likewise, V̇O 2 peak increased from 18.3 to 21.6 ml/min/kg (+18 ± 27%, p < 0.001) to reach 72% of predicted values. Maximal strength and the number of contractions during the fatigability test increased between T1 and T2 by 41% and 39%, respectively (both p < 0.001). Conclusions Six months of recovery improved patients' physical function and reduced fatigue
Impact of grazing by multiple Daphnia species on wastewater bacterial communities
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Altérations du tissu musculaire squelettique induites par l’exercice et capacités de régénération : variabilité intra-musculaire et différences liées au sexe
No full textCe document est une synthèse de mon activité de recherche depuis la fin de ma thèse en novembre 2010. Cette activité s’est articulée autour du développement de méthodologies innovantes et/ou de l’utilisation de technologies émergentes d’imagerie permettant une meilleure évaluation de la variabilité spatiale des caractéristiques musculaires et tendineuses et de leurs adaptations à des sollicitations aigues (i.e., aux dommages induits par l’exercice) et chroniques (i.e., entrainement pliométrique). L’évaluation des différences liées au sexe et plus spécifiquement de l’environnement hormonal féminin constitue un fil rouge de mon activité de recherche. Un des objectifs de mes travaux était de contribuer à une meilleure compréhension du fonctionnement du système musculo-tendineux et l’identification des mécanismes physiologiques potentiellement impliqués dans l’adaptations des caractéristiques musculaires et tendineuses.Les principaux résultats de mes récents travaux concernent des adaptations locales du muscle strié squelettique dans un contexte de dommages sévères induits par des contractions évoquées électriquement. Ces adaptations aux dommages musculaires ont été mises en évidence par l’utilisation de traitements spécifiques de données d’imagerie par résonance magnétique et la complémentarité d’approches méthodologiques permettant l’évaluation multimodale des conséquences fonctionnelles, anatomiques et métaboliques. La supplémentation protéique comme stratégie d’atténuation des conséquences de dommages musculaires induits par l’exercice a par ailleurs été évaluée, montrant des effets bénéfiques limités voire inexistants pour des dommages sévères. Enfin, des différences liées au sexe ont été mises en évidence impliquant une réflexion plus large sur les spécificités à apporter aux interventions en fonction du sexe pour l’optimisation de la performance et la prévention des blessures. Les travaux de recherche exposés dans ce document relatent les nouvelles connaissances qui ont émergées de ces travaux et les projets de recherche envisagés.Les perspectives de recherche sont structurées autour de trois orientations principales. La première orientation concerne l’amélioration de l’approche méthodologiques pour évaluer plus précisément les variabilités spatiales des caractéristiques tissulaires. Les différences d’environnement hormonal entre les hommes et les femmes, en fonction du cycle menstruel et la prise d’un contraceptif oral sur la sévérité des dommages induits par l’exercice, ainsi que les capacités de récupération fonctionnelle avec un cadre d’évaluation plus holistique prenant en compte les caractéristiques du sommeil et les effets de l’âge, constituent une seconde orientation. Enfin, l’étude des adaptations à l’entrainement pliométrique et les mécanismes sous-jacents permettant une amélioration des performances constitue la troisième orientation de mes projets de recherche. La finalité de l’ensemble de ces perspectives de recherche est d’identifier les mécanismes physiologiques impliqués lors de la dégradation, la régénération et l’adaptation du tissu musculaire afin de faire progresser la prévention des blessures, le retour optimisé à l’activité physique et l’amélioration de la performance sportive.</div
Thermochronology of the Maures-Tanneron crystalline basement: insights for SW Europe Triassic to Miocene tectonic history
No full textInternational audienceThis paper presents a thermochronological study of the Western European basement in the Maures-Tanneron massif (MTM), using zircon and apatite fission-track data, in addition to apatite (U-Th-Sm)/He analyses. The combination of these methods with inverse thermal modelling allows us to trace the thermal history of this massif from the Late Triassic to the present day. The study identifies several thermal events that are linked to two major tectonic phases at 120-40 Ma and 40-15 Ma. These new results prompt us to re-evaluate the thermal evolution and exhumation of Western European basement of the Provence region. We distinguish four episodes. (i) A period characterized by constant temperature contemporaneous with Triassic magmatic activity and Tethys rifting (ii) a period of sedimentary burial heating of the MTM associated with the Cretaceous Pyrenean rift evolution (iii) subsequent N-S Pyrenean inversion at 75 Ma, causing cooling and exhumation of the MTM, (iv) opening of the West European rift system and the Liguro-Provençal basin, which resulted in heating from 35 to 15 Ma and post 15 Ma cooling of the MTM. This study also provides insights into the paleogeography of the MTM and demonstrates its evolution at the cross-roads between the Pyrenean and Alpine orogens
Investigating the relationship between positive eco-emotions and pro-environmental responses
No full textInternational audienceTo face the major challenges posed by environmental crises, it is necessary to make behavioral decisions beneficial for the environment – in other words, to adopt pro environmental behaviors. Among the factors influencing pro-environmental behavior, emotions linked to environmental crises, or eco-emotions, play a key role (Brosch et al., 2021). On the one hand, existing research points to the beneficial influence of certain negative eco-emotions on motivation to act pro-environmentally. However, on the other hand, the potential drawbacks of negative eco-emotions are beginning to be recognized (e.g., Gago et al., 2024; O’Neill & Nicholson-Cole, 2009). While negative emotions have been widely studied as unpleasant and sometimes harmful to mental health, this is less the case for positive emotions (Fredrickson, 2000). In this context, we carried out a cross-sectional study (N = 502) to explore the relationship between positive eco-emotions and pro-environmental responses. We found that positive eco-emotions were moderately to strongly associated with pro-environmental collective action intentions. Of course, we cannot infer causality from these data and conclude that positive eco-emotions impact pro-environmental responses. Therefore, we next wanted to see whether positive eco-emotions such as awe or compassion have an impact on a real pro-environmental behavior. However, to compensate for the lack of empirically validated experimental material for inducing positive eco-emotions, we undertook two studies to validate the procedure for inducing eco-compassion (N = 167) and awe of nature (N = 118). The results showed that we successfully induced eco-compassion in the video condition but not in the autobiographical recall condition. As for awe of nature, emotional induction was successful but this time in both emotional induction conditions. We now have experimental material for inducing two positive eco-emotions, enabling us to study their effects on pro-environmental behavior in a controlled way