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Measurements of and productions in collisions at TeV with the ATLAS detector
No full textInternational audienceThis article presents measurements of boson pair production cross-sections at a center-of-mass energy of TeV, using 140 fb of proton-proton data collected with the ATLAS detector at the Large Hadron Collider. The analysis includes both inclusive production and production in association with two jets (), where one boson decays into a pair of charged leptons (), and the other decays into a neutrino pair. The measured fiducial cross-section of the inclusive production is fb, while for the production it is fb. Extrapolation of the cross-section to the full phase space, for bosons within the mass range ~GeV, yields pb. Differential cross-sections are presented for an extended set of kinematic observables. The results are found to be in good agreement with Standard Model predictions. Constraints on anomalous gauge boson self-interactions are derived using both the vertex function formalism and the effective field theory framework
Response to methodological criticisms: reliable support for the simulation of negated actions in the primary motor cortex
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Modéliser les dynamiques thermiques du permafrost dans les pentes d’éboulis : étude de cas d’un site récemment déstabilisé (glissement de Gislá, 6 octobre 2020, Islande)
No full textInternational audienceThe degradation of permafrost enhances the occurrence of landslide in mountain environments. Therefore, predicting permafrost boundaries is crucial to mitigate hazards to populations and infrastructures. In the present study we investigate the Eyjafirði talus slope (Tröllaskagi peninsula, Iceland), from which a landslide occurred in 2020. Although this talus slope is located outside of the permafrost climatic boundaries, geomorphological evidence points towards an involvement of degradation of azonal permafrost in the generation of the landslide. However, the thermal dynamics of talus slopes is currently poorly understood, as air convection (the 'chimney effect') can play a role in the persistence of permafrost at the base of talus slopes. We use the commercial software FEFLOW to run two-dimensional (2D) physical-based simulations of heat transfer within a cross-section of the Eyjafirði talus slope. We create forcing temperature time series by statistical reconstruction (back to November 1881) and modelling (back to -20,000 years), based on temperature measurements acquired in 2021-2022. We explore the sensitivity of our model to i. the initial porosity/ice content of the talus slope (0.3, 0.5 and 0.8), and ii. the thermal conductivity (TC) of the rock phase (0.75, 1.1 and 1.75 W.m -1 .K -1 ). Our temperature measurements show that a chimney effect indeed occurs at the Eyjafirði talus slope. Although our modelling approach does not simulate air convection itself, permafrost indeed persists at the base of the talus slope in all model scenarios. Increasing the initial porosity/ice content and decreasing the TC of the rock phase generates a larger zone with sub-zero temperatures at the base of the talus slope, which leads to a larger zone where ground ice persists with an overall higher ice content. Our approach is unconventional as we initially know that ground ice was present in the Eyjafirði talus slope at the time of the landslide; it allows us to attest that the permafrost dynamics in the talus slope is best represented by our most ice-conservative scenarioi.e. with a TC = 0.75 W.m -1 .K -1 . Such a low TC is atypical based on the literature; we suggest that this low value could have partly compensated for the cooling effect of air convection (i.e. chimney effect).Dans cet article, nous étudions la pente d’éboulis d'Eyjafirði (péninsule de Tröllaskagi, Islande du nord), où un glissement de terrain (une avalanche de débris) s'est produit en octobre 2020. Cet éboulis est situé en dehors des limites climatiques du permafrost, mais des indices géomorphologiques (i.e., des molards présents dans les dépôts de glissement) indiquent que la dégradation de permafrost azonal pourrait faire partie des facteurs déclenchants du glissement de terrain. La dynamique thermique des éboulis est actuellement mal comprise, car la convection de l'air (effet de cheminée) joue un rôle dans la persistance du pergélisol à leur base.Nous utilisons donc le logiciel FEFLOW pour effectuer des simulations physiques en deux dimensions du transfert de chaleur dans l’éboulis d'Eyjafirði, de -20 000 ans à l’actuel. Nous testons la sensibilité de notre modèle à la porosité initiale/la teneur en glace de l’éboulis (0,3, 0,5 et 0,8), et la conductivité thermique (TC) de la phase rocheuse (0,75, 1,1 et 1,75 W.m-1.K-1).L’analyse des températures de l’air montre un réchauffement général depuis les dernières ~ 40 années, soutenant l’hypothèse que la dégradation de permafrost pourrait faire partie des facteurs déclenchant du glissement de terrain. Bien que nous ne modélisions pas la convection de l'air, le pergélisol persiste à la base de l'éboulis dans tous les scénarios. L'augmentation de la porosité initiale/de la teneur en glace et la diminution de la TC de la phase rocheuse intensifient cette persistance du pergélisol dans l'éboulis. Notre approche n'est pas conventionnelle, car nous savons que de la glace était présente dans l’éboulis au moment du glissement de terrain. Nous en déduisons donc que la dynamique du pergélisol dans l’éboulis d’Eyjafirði est donc mieux représentée par le scénario avec une TC de 0,75 W.m-1.K-1
DYNAMICS OF THE REVERSIBLE GRAY-SCOTT MODEL AND CONVERGENCE TO ITS IRREVERSIBLE LIMIT
No full textWell-posedness of a reversible variant of the Gray-Scott model is shown, along with the convergence of each trajectory to one of the two spatially homogeneous steady states. The principle of linearized stability provides the local attractivity at an exponential rate of the stable steady state, while the long-term limit is identified with the help of center manifold theory. Finally, convergence to the classical Gray-Scott model is proved for an appropriate choice of parameters.</div
Ericaceous shrub encroachment influences the structure of soil fungal communities in subalpine grasslands
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Physical inactivity and sedentary behaviours: screening and intervention in primary care, a prospective, multicentre, cluster-randomised, controlled, stepped-wedge study
No full textInternational audienceAbstract Background Physical inactivity and sedentary behaviours (PiA/SED) are among the major modifiable risk factors for chronic diseases. Behaviour change models for PA can shape personalised interventions leading to sustainable lifestyle changes. We hypothesise that screening for PiA/SED by a general practitioner, followed by a personalised intervention by a physiotherapist, could reduce PiA/SED in inactive adults. Methods We designed a prospective, multicentre, cluster-randomised, controlled, step-wedge study. Adult patients without chronic illnesses will be recruited in 8 multi-professional health centres. They will receive educational content on PiA/SED. During the intervention periods, patients will see a physiotherapist for a functional assessment, and an intervention aimed at improving PiA/SED using a serious game. Two follow-up appointments at months 2 and 4 (M2-4) are planned to maintain patient motivation. At M6, a 7-day actimetry will be performed, and at M6-12, questionnaires and semi-structured interviews will close the study. Two primary endpoints will be analysed using a pre-specified hierarchical sequential analysis: the proportion of patients changing PiA/SED at M6. Secondary objectives include: 1-describing changes in PiA/SED at M6 and M12, 2-exploring the link between patient characteristics and changes in PiA/SED, 3-describing participants’ quality of motivation, satisfaction of basic psychological needs, feelings of self-efficacy, perceived levels of vitality and energy, and self-esteem, 4-describing the strategies, barriers and facilitators of behavioural changes, 5-studying the correlation between questionnaires measuring physical activity and actimetry, 6-identifying the perceived barriers and facilitators to implement this care pathway. Assuming that 10% of patients in the control period will improve their PA and that the intervention will increase it by 20%, 160 patients provides 82% power to observe a significant difference. Discussion This design will harmonise the skills of all professionals in the field of motivational support for PiA/SED and providing information about the risks associated with PiA/SED. Patients in the intervention group will also receive individual support for behaviour changes related to PiA/SED. Considering public health, this study will contribute to increase primary prevention by healthcare professionals. Finally, this study will assess the effectiveness, adherence, satisfaction of the stakeholders involved in this pathway allowing to consider its implementation in routine primary care. SPIRIT 2025 checklist of items see supplement files. Trial registration ClinicalTrials n° NCT06678906, https://clinconnect.io/trials/NCT06678906#about-company-tab , first registration October 14, 2024, Trial updated February 05, 2025
Boosting hemianopia recovery: the power of interareal cross-frequency brain stimulation
No full textInternational audienceAbstract Visual field loss is a common consequence of stroke and manifests in approximatively one-third of patients in the chronic stage. Such loss can significantly impact daily life activities, compromising tasks such as reading, navigating or driving. Although slow and labour intensive, evidence suggests that early interventions with tailored rehabilitation programmes might stimulate visual recovery and improve quality of life in stroke survivors. To enhance the effects of such rehabilitation programmes, we designed a novel, non-invasive, pathway-specific, physiology-inspired cross-frequency brain stimulation protocol, where complex oscillatory signal integration was inferred from phase–amplitude coupling of oscillatory signals between the primary visual cortex and the motion-sensitive medio-temporal area. Sixteen stroke patients were enrolled in a double-blind, randomized, cross-over trial, during which they performed two blocks of 10 daily training sessions of a direction discrimination task, combined with one of the two cross-frequency transcranial alternative brain stimulation (cf-tACS versus control cf-tACS) conditions. We found that the cf-tACS condition promoting feedforward visual inputs to the medio-temporal area significantly enhanced motion discrimination performance and shifted visual field borders (i.e. through localized enlargement of isopters). Behavioural improvements associated with a change in oscillatory activity within motion processing pathways were proportional to the amount of residual structural fibres along these pathways and perilesional primary visual cortex activity. In sum, we report, for the first time, that cf-tACS, a novel, pathway-specific, physiology-inspired brain stimulation approach, is able to boost the efficacy of perceptual training, restoring visual motion processing and reducing the severity of visual impairments in adult stroke patients
Redox aspects of lithium-ion batteries. Is graphite an anode?
No full textInternational audienceGraphite is the most commonly used negative electrode in lithium-ion batteries. This perspective article reviews the charge transfer aspects of the graphite electrode, presenting the different mechanisms of the graphite electrode involved during its charging from an electrochemical standpoint. Different reaction mechanisms can be distinguished: (1) adsorption of solvated lithium ions on negatively charged graphite, (2) intercalation of de-solvated lithium ions in graphite as a solid solution, (3) biphasic (liquid–solid) formation of solid LiC36 and LiC12 phases, (4) biphasic (solid–solid) formation of a LiC6 phase and (5) under potential deposition of lithium atoms on the LiC6 phase, which may be followed by classical electroplating of Li+ on Li. Only the last electrodeposition reactions are truly a redox process. The other reaction mechanisms represent the potentiometric titration of carbon sites for lithium ion adsorption and intercalation
Statistical modelling of permafrost distribution in steep rock slope, application to the French Alps
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Permafrost in the Pyrenees: the changing mountains
No full textInternational audienceThe cryosphere in the Pyrenees is undergoing profound transformations due to climate change, leading to significant hydrological, geomorphological,and environmental shifts. Rising temperatures have dramatically reduced snow cover and accelerated the retreat ofPyrenean glaciers, which are expected to disappear entirely in the coming decades. While snow and ice dynamics are closely monitored,much less is known about permafrost. The southern character of the Pyrenees makes this region particularly unique and significantin permafrost studies, as it introduces specific challenges in understanding the behavior and vulnerability of permafrost to futurewarming. Currently, permafrost is found only at the highest elevations, typically above 2,600 m, with rare occurrences between 2,350and 2,400 m. Its recent behavior and vulnerability remain poorly understood, and studying permafrost is also essential for anticipatinghazards associated with its thaw, such as increased rockfalls, landslides, or moraine collapses. These risks have already impacted infrastructure,including trails in popular areas like Aneto and Vignemale. This communication presents preliminary findings from the ongoingPERMAPYRENEES project (Interreg Poctefa EFA063/01), which utilizes advanced in-situ and remote sensing techniques to detect permafrostand assess related hazards. The project’s key components include: (i) Geophysical surveys to identify the presence of frozenground; (ii) Six deep boreholes in high-elevation areas to monitor subsurface conditions; (iii) Loggers in rock walls to track permafrost dynamicsin steep bedrock; (iv) InSAR measurements to detect ground deformation rates; (v) Reconstruction of past permafrost environments,with a focus on rock glaciers; (vi) Analysis of rock properties to better understand permafrost behaviour; and (vii) Mapping permafrostdistribution and identifying potentially hazardous areas. Beyond establishing a pioneering observational network in the Pyrenees,the project also aims to raise public awareness of climate change impacts and provide policymakers, land managers, and plannerswith critical data to mitigate risks in areas with significant infrastructure