HAL-Université de Bretagne Occidentale
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Accommodative Response to Asymmetrical Accommodative Stimuli
No full textInternational audienceRecent advancements in head-up-displays have increased the number of instances where the visual system may face a different accommodative demand for each eye. A limited number of studies on aniso-accommodation exist, reporting contradictory results. We tested the natural capacity of observers to aniso-accommodate anisometropic stimuli. A dichoptic task allowed us to account for certain confounds, including high-level accommodation control. A 2AFC visual task was used, where participants judged if two overlapping sinusoidal gratings, presented dichoptically, had the same orientation. The gratings’ spatial frequency could be 1, 4 or 10 c/deg. The accommodative demand for each eye could be independently set to 2D or 4D. The accommodative response for each eye was recorded using an autorefractometer. Higher spatial frequencies and anisometropy had a negative impact on task accuracy. Contrary to expectations, spatial frequencies had no significant impact on accommodation response. The accommodation response to anisometropic stimuli was equal in the two eyes and leaned toward the lower of two demands. Our results confirm that when presented with asymmetrical accommodation demand, the two eyes tend to keep the same refractive power even in a dichoptic-requiring task. They also contradict the guidance of accommodation by spatial frequency in sinusoidal gratings. The visual task provided an objective measure of subjects’ performance, allowing for these conclusions to be drawn
A stakeholder perspective on the drivers and barriers influencing the emergence of deep-sea mining
No full textInternational audienceThe identification of drivers and barriers influencing the initiation of commercial deep-sea mining (DSM) is key to developing research approaches to support the development of adequate DSM management frameworks. This study aims to provide a systems-level understanding of DSM drivers and barriers integrating both academic literature and diverse stakeholder perspectives (industry, NGOs, policy-makers, and academic researchers). To this end, we carry out a political, economic, social, technological, environmental, and legal (PESTEL) analysis combining the results of a literature survey, a participatory workshop, and semi-structured interviews. The results provide a broad overview of scientific knowledge and uncertainties relating to DSM drivers and barriers identified in the literature, alongside a synthesis of emerging perspectives and concerns expressed by stakeholders during the participatory workshop and interviews. The discussion highlights both areas of consensus and divergence across stakeholder groups and the literature, as well as a critical reflection on the relevance and limitations of the PESTEL approach, highlighting research needs to further support holistic decision making around DSM.</div
Le travail du groupe Occitanie : point d’étape - Projet RAME
No full texthttps://rame.hypotheses.org/en-occitanieNous présentons ici les premiers résultats des discussions du groupe de travail Occitanie dans le cadre du projet de recherche sur les aires marines éducatives (RAME). Depuis leur première réunion en mai 2024, les participants sur le secteur Occitanie ont pu identifier des axes d’étude prioritaires à investir dans le cadre du projet ; un ensemble d’outils méthodologiques a commencé a être déployé en collaboration avec des AME et ATE du territoire, afin de documenter les axes d’étude retenus
Concurrence déloyale et parasitisme : importantes précisions sur la réparation des préjudices: note sous Cass. com., 9 avr. 2025, n° 23‐22.122, B
No full textInternational audienceRendu à l’occasion d’une action en concurrence déloyale intentée par plus d’une centaine d’artisans taxis contre la plateforme UBER, accusée d’avoir bénéficié d’un avantage concurrentiel indu grâce à son application UBER POP, l’arrêt commenté offre à la Cour de cassation l’occasion d'apporter d'importantes précisions s'agissant de la preuve des préjudices concurrentiels, qu'il s'agisse du préjudice économique ou du préjudice moral
<i>Vibrio</i> are a potential source of novel colistin-resistance genes in European coastal environments
No full textInternational audienceColistin is a widespread last resort antibiotic for treatment of multidrug-resistant bacteria. The recent worldwide emergence of colistin resistance (Col-R) conferred by mcr-1 in human pathogens has raised concern, but the putative sources and reservoirs of novel mcr genes in the marine environment remain underexplored. We observed a high prevalence of Col-R, particularly in Vibrio isolated from European coastal waters by using the same cohorts of oysters as bioaccumulators in three sites across Europe. The high sequence diversity found in the mcr/eptA gene family was geographically structured, particularly for three novel eptA gene variants, which were restricted to the Mediterranean (France, Spain) and occurred as a dgkA-eptA operon. The RstA/RstB two component system was shown to control both the dgkA-eptA operon and the Col-R phenotype. The analysis of 29 427 Vibrionaceae genomes revealed that this mechanism of intrinsic resistance is prevalent and specific to the Harveyi clade, which includes the human pathogens Vibrio parahaemolyticus and Vibrio alginolyticus. The operon conferred colistin-resistance when transferred to sensitive non-Vibrio strains. In general, eptA gene variants are widespread and evolved with the Vibrio lineage. They occur in clade-specific genomic environments, suggesting that eptA expression responds to distinct environmental signals across the Vibrio phylogeny. However, we also identified mobile eptA paralogues that have been recently transferred between and within Vibrio clades. This highlights Vibrio as a potential source of Col-R mechanisms, emphasizing the need for enhanced surveillance to prevent colistin-resistant infections in coastal areas
How marine heatwaves are reshaping phytoplankton in the Northeast Pacific
No full textInternational audienceAbstract In 2015 and 2019, the Northeast Pacific has undergone significant heatwave events that strongly disrupted marine ecosystems functioning and services. Here we use the data collected by the Continuous Plankton Recorder (CPR) survey to investigate the changes in summer phytoplankton abundance and morphology and show an increase in prolate (i.e., elongated) taxa during heatwave events, in response to warmer temperatures and declining nitrate. We also investigate the impacts of the morphological shifts on the carbon cycle and show that warmer periods were dominated by prolate cells with high carbon content, whereas cooler periods were dominated by oblate (i.e., flattened) cells with low carbon content. By altering community composition and the overall cells sinking velocity, these morphological shifts likely impacted the carbon cycle, as they were correlated with changes in surface chlorophyll a and particulate organic carbon concentrations
Évaluation des effets de la sécheresse et de l'urbanisation sur les arbres urbains à l'aide de la série temporelle Sentinel-2
No full textInternational audienceUrban trees provide essential ecosystem services, including temperature regulation, carbon storage, and biodiversity conservation, which are crucial for enhancing urban living conditions. However, they are exposed to various stress factors in urban environments, such as limited light, restricted growth space, and increased exposure to pollutants. Moreover, climate forecasts predict an increase in the frequency and severity of droughts and drought events which can lead to tree defoliation, increased sensitivity to pests and pathogens and therefore increase tree mortality. Quantifying and monitoring the response of urban trees to stress factors can be used as a proxy for tree health assessment.The effects of stress factors (drought, urban conditions) on urban trees dynamics have already been observed in situ with dendrochronology and biochemical analysis. These effects have been shown on a large scale using remote sensing data, but the coarse spatial resolution of the data used (MODIS, 250m) make it impossible to discriminate species that suffer from stress from those that are more resilient. We first investigated tree dynamics in Rennes (France) at fine spatial scale using Sentinel-2 time series to analyze the impact of drought events and urbanization on tree health. Specifically, we analyzed five deciduous tree species (Platanus Acerifolia, Acer Platanoides, Fraxinus Excelsior, Quercus Rubra and Quercus Robur) during two years characterized by very contrasting climatic conditions (2021 and 2022) and along an urban-rural gradient. Vegetation dynamics were monitored using a vegetation index (ARVI). Phenological, productivity and disturbance metrics which characterize respectively key dates and growth-cycle duration, tree growth and productivity, and intra-annual anomalies in tree-dynamics, were derived from the ARVI filtered time-series. Drought events were characterized using a standardized precipitation index derived from climate data and urban intensity was determined at pixel-scale using the Copernicus’ Imperviousness Density data. Temporal metrics values were aggregated at patch-scale (group of contiguous trees of the same species). The results showed a notable extension in the length of the growing season and maturity periods for four species in 2022 (the driest year), driven primarily by delayed senescence and end-of-season dates. Productivity metrics displayed mixed responses, with some species showing reduced growth under drought, while others, like Platanus Acerifolia, exhibited increased productivity, suggesting potential resilience mechanisms. Elevated disturbance levels were observed in 2022, indicating higher stress conditions compared to the previous year. Furthermore, the results outlined that urban intensity was most often correlated with extended growing seasons and altered productivity dynamics. Based on these results, we then developed an exploratory approach at the city scale to identify trees with unusual temporal profiles that correspond to exacerbated trees responses to stress factors. We determined a reference profile for each tree species, corresponding to the average profile of trees growing in similar and contrasting urban conditions, and compared tree profiles to this reference profile based on statistical analysis. This analysis was conducted for period 2016-2024 to monitor tree disturbance levels. This tool can be used by urban tree managers to locate, guide and schedule in situ investigations to monitor tree health and potentially identify trees in decline. This study underscores the value of Sentinel-2 time series in supporting urban tree management and policy decisions amidst changing environmental and climate conditions
Coéducation : que disent les résultats de cette enquête ?
No full textEntretien « Coéducation : que disent les résultats de cette enquête ?». Dans L'expresso du café pédagogique. Entretien réalisé par D. Gani. En ligne (2025) : https://www.cafepedagogique.net/2025/06/26/coeducation-que-disent-les-resultats-de-cette-enquete/"Comment s’actualisent aujourd’hui – à l’ère des politiques incitant au partenariat – les rapports entre les familles, les acteurs de l’association et ceux des établissements scolaires alentours ? » Aline Grasperge est doctorante en sciences de l’éducation et de la formation à l’université Rennes 2, rattachée au Centre de recherche sur l’éducation, les apprentissages et la didactique (CREAD). À l’ère des politiques de coéducation, encourageant les acteurs éducatifs à travailler de concert avec l’École pour la réussite éducative des enfants et des jeunes, ses travaux interrogent la mise en œuvre concrète de ces intentions sur le terrain. Dans le cadre d’une enquête en immersion dans une association d’éducation populaire parisienne, elle analyse plus particulièrement les relations entre les familles, les acteurs de l’association et ceux des écoles du quartier. Le Café pédagogique l’interroge sur ses travaux.
Épidémiologie des traumatismes de l'extrémité céphalique chez les militaires français déployés en opérations extérieures : l'exemple du Mali
No full textBackground - Head and neck injuries stand for 26% to 36 % (in Iraq and Afghanistan) of war-related injuries. They are responsible for specific injuries most of war related are penetrating injuries. Between 2013 and 2022, French soldiers were deployed to the Sahel region during the Serval and Barkhane operations. The aim of this study is to collect the incidence of war-related head and neck injuries between January 2013 and December 2021. Methods - Data were collected among French soldiers repatriated to France for a head and neck war-related trauma from January 11, 2013 to December 31, 2021. 80 French soldiers were included. Results - In this study, head and neck injuries counts for 7% of all trauma in abroad operation. Among war-related trauma, the incidence is 35.4%. The main mechanisms of injury are explosions for 63% and gunshot wounds for 3%. 24% had a head and neck surgery on the field. Mortality rate is 4%. Conclusion – Head and neck trauma are common during operations abroad. They represent 35.4% of war-related injury in Mali. Ongoing studies on the conflict in Ukraine and screening wound mapping should help to adapt care and personal protective equipment in the future.Introduction - Les traumatismes de l'extrémité céphalique représentent entre 26% et 36% (Irak et Afghanistan) des traumatismes au combat. Les traumatismes de guerre sont responsables de lésions spécifiques avec une plus grande part de traumatisme pénétrant. Entre 2013 et 2022, les militaires français ont été déployés au Sahel pendant les mandats SERVAL et BARKHANE. L'objectif est de relever l'incidence des traumatismes de l'extrémité céphalique entre janvier 2013 et décembre 2021. Matériels et méthodes - Les données ont été recueillies parmi les militaires français rapatriés en métropole pour un traumatisme de l'extrémité céphalique entre le 11 janvier 2013 et le 31 décembre 2021. 80 militaires français ont été inclus dans l’étude. Résultats - Dans cette étude, les traumatismes de l'extrémité céphalique représentent 7% de l'ensemble des traumatismes en opération extérieure. L'incidence des traumatismes de l'extrémité céphalique par rapport aux traumatismes de guerre est de 35,4%. Les mécanismes lésionnels prédominants sont l’explosion dans 63% des cas et les plaies par balle dans 3% des cas. 24% ont bénéficié d’une chirurgie sur le terrain. Le taux de mortalité est de 4%. Conclusion – Les traumatismes de l’extrémité céphalique sont courants en opération extérieure et représentent 35,4% des traumatismes de guerre au Mali. Les études en cours sur le conflit en Ukraine et les études de screening systématique permettront d’adapter la prise en charge et les équipements de protection individuelle dans le futur
