Portail HAL Nantes Université
Not a member yet
120169 research outputs found
Sort by
« Une réforme surtout pour les mots »
No full textInternational audience(Loi no 2025-622 du 9 juillet 2025 créant l'homicide routier et visant à lutter contre la violence routière
法国早期汉学形成过程中传教士与法国学者的贡献
No full textInternational audienceDans l’Europe des XVIIe et XVIIIe siècles, le mythe biblique de la Tour de Babel était toujours très vivant. On s’interrogeait sur ce que pouvait être cette langue originelle de l’Humanité, perdue depuis des millénaires du fait du châtiment divin. Lorsque, dans les dernières années du XVIIe siècle, décidée par Louis XIV et Colbert, la mission des Jésuites, promus à cette occasion « Mathématiciens du Roi », permit à l’Europe, en particulier à la France, de découvrir la Chine et, bien sûr, sa langue plurimillénaire, reposant sur un système d’écriture ressemblant à des hiéroglyphes et donc rappelant l’Égypte ancienne, le débat entre savants, théologiens et philosophes, prit un nouvel essor
Microplastics quantification in organic-rich samples: the relevance of testing substrate-specific calibration curves
No full textInternational audienceUrban agriculture could rely on waste-based substrates, but potential contaminants such as microplastics should be evaluated for safe public use. However, quantifying macroplastics in these substrates is challenging due to their high organic matter content, which is difficult to remove completely, leading to interfering compounds and unreliable results. This study investigated the underexplored effects of organic matter on microplastics quantification employing pyrolysis-GC-MS. Natural organic matter (NOM) removal methods were tested on organic-rich peat-based substrate, reaching up to 46% of reduction with Fenton’s reaction. Then, calibration curves were prepared in two inorganic matrices, silicon dioxide and glass fiber powders, for high density polyethylene (HDPE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC) across nine concentrations, from 0.01 to 10 µg/mg, adding polyflurostyrene (PFS) as internal standard. The selectivity of several polymer pyrolytic markers was compared. Polymer-spiked samples were subjected to Fenton’s oxidation and quantified with both inorganic calibration curves, overestimating polymer contents, up to four times for PET and PVC. The preparation of a third calibration curve, specific for peat, improved results for PS, but not for PP, PET, and PVC. For the first time, the three calibration curves were tested on untreated polymer-spiked (HDPE, PP, PS) waste-based substrates, and resulted in a better estimation closer to the expected polymer concentrations when substrates closely matched the curve’s matrix composition. The comparison of three calibration curves made with different matrices showed that the quantification of plastic polymers in organic-rich samples could be improved using matrix-specific calibration curves even without a complete NOM removal. This represents a novel methodological approach for plastic polymers quantification in complex matrices, minimizing the sample pre-treatment that could cause the loss of nanoparticles during filtration, evidencing that matrix similarity is key for reliable quantification in NOM-rich samples, even without its complete removal
Examining coping among adolescent athletes in an intensive training centre: A profile analysis
No full textInternational audienceIntensive training exposes adolescent athletes to numerous stressors, presenting both challenges to be overcome and opportunities. The athletes' ability to cope with stress and maintain effective social interactions is essential to preserving well-being and performance. Using a person-centred approach, this study had three objectives: (a) identify the coping profiles of adolescent athletes in intensive training centres, (b) examine the influence of perceived social support on profile membership, and (c) characterise the adaptive nature of these profiles in relation to stress perception, subjective performance, well-being and emotions. A sample of 461 adolescent athletes (female = 59 %; M age = 17 ± 1.3) competing at national (82 %) or international (18 %) levels, completed a questionnaire on perceived availability and satisfaction with parental and coach support, individual coping, stress perceptions, subjective performance, well-being and emotions. The results yielded four distinct coping profiles, whose membership varied according to perceived social support: low-, engaged-, moderate-and disengaged coping profiles. The MANOVA revealed differences in stress perception, subjective performance, well-being and emotions across coping profiles, with the disengaged profile standing out for its particularly low levels of well-being, pleasant emotion direction and subjective performance, and high levels of unpleasant emotion intensity and direction. These results enhance understanding of adolescent athletes' coping profiles in intensive training centres and highlight the role of their entourage in helping them manage stress effectively. They confirm the multidimensional nature of coping and provide valuable guidance to athletes' support networks on how to offer appropriate support in their pursuit of excellence.</div
Antigone lève-toi ! Quand théâtre et philosophie se rencontrent au collège
No full textInternational audienceQuestionner les notions de justice et de liberté à travers le jeu dramatique, tel était l’objectif d’un dispositif mis en place dans un établissement du Sud Sarthe. Relier la réflexion conceptuelle et l’expérience sensible ouvre un espace où la parole philosophique se nourrit de la créativité théâtrale
StripesCounter: A new image software for increment measurement in paleoclimate archives
No full textInternational audienceMost natural paleoclimate archives are accretionary material presenting periodic structures that bear environmental and/or chronological information. Here we present StripesCounter, an open access Python software designed for automated banding detection and measurement. As a study case, 16-year long profiles of daily growth increment measurements were conducted on a modern shell of the giant clam Tridacna gigas. High resolution images of shell thin sections were obtained using a confocal laser scanning microscopy and processed using StripesCounter. We demonstrate that StripesCounter provides highly reproducible and accurate results. The long time series of daily increments indicate that Tridacna gigas growth is strongly modulated by seasonal oceanographic variations, reflecting changes in sea surface temperature, precipitation, and salinity. Notably, growth profiles reveal semi-annual variations related to semi-annual variations in environmental factors, potentially linked to ENSO events. This automated growth increment analysis can be extended to other archives with cyclic structures, including tree rings, corals, and other biogenic or abiotic laminated materials. StripesCounter offers a powerful and accessible tool for generating long high-resolution, temporally explicit datasets, opening new perspectives for investigating rapid environmental changes across diverse ecosystems and geological timescales
Tara Polaris expeditions: Sustained decadal observations of the coupled Arctic system in rapid transition
No full textThe coupled Arctic system is in rapid transition and is set to undergo further dramatic changes over the coming decades. These changes will lead most likely to an ice-free ocean in summer, expected before mid-century. The Arctic will become more strongly influenced by atmospheric and oceanographic processes characteristic of mid-latitudes, increasing the prevalence of contaminants and new biological species. This ongoing transition of the Arctic to a new state necessitates systematic monitoring of all sentinels (variables that make an essential contribution to characterizing the Earth's state) to improve our understanding of the system, enhance forecasting and support knowledge-based decisions. Here, we describe a sustained multi-decadal observation program to be implemented on the Tara Polar Station between 2026 and 2046. The monitoring program is designed as a series of year-long drift expeditions, called Tara Polaris, in the central Arctic Ocean, covering all seasons. The multidisciplinary data will bridge ecological, geochemical, biological, and physical parameters and processes in the atmosphere, sea ice and ocean. In addition, data collected with consistent methodologies over a 20-year period will make it possible to distinguish long-term trends from seasonal and interannual variability. In this paper, we discuss specific measurement challenges in each compartment (i.e., atmosphere, sea ice and ocean) along key sentinels and the most pressing scientific questions to be addressed. The expected outcomes of the Tara Polaris program will enable us to understand and quantify the main feedbacks of the coupled Arctic system, with their seasonal and interannual trends and spatial variability.</div
Toward dimensional body consciousness impairments in post-traumatic stress disorder and its dissociative subtype: a predictive processing approach
No full textInternational audienceCurrent models of post-traumatic stress disorder (PTSD) predominantly focus on emotional dysregulation, avoidance behaviors, and intrusive symptoms, with limited attention to disturbances in bodily self-consciousness. These frameworks do not fully account for how trauma may disrupt the integration of interoceptive and exteroceptive signals underlying the sense of embodied self. Building on recent advances in computational psychiatry, this review introduces a novel theoretical framework that differentiates between dissociative and non-dissociative forms of PTSD using the predictive processing paradigm. Body awareness, including the sense of body ownership (SBO) and the sense of agency (SoA), is framed within a Bayesian inference framework, where perception results from the interaction between prior beliefs and incoming sensory information. In non-dissociative PTSD, we suggest that hyperprecise trauma-related priors, coupled with increased interoceptive weighting due to amygdala and anterior insula hyperactivity, result in rigid self-representations and a diminished capacity for perceptual updating. Thus, we may consider PTSD as a state in which accuracy and reliability of cognitive processes are ranked as follows: [Prior > Interoception > Exteroception]. Conversely, in the dissociative PTSD subtype, emotional over-inhibition and anterior insula hypoactivity weaken priors and interoception, while exteroceptive inputs dominate. Therefore, we consider ranked cognitive processes in PTSD dissociative subtype as follows: [Exteroception > Interoception > Prior]. SoA impairements is specific to the dissociative subtype involving hyperactivity of the angular gyrus and glutamate hypofunction. On this basis, we propose an original dimensional model of body consciousness disruption across PTSD spectra. Therapeutic implications are explored, including top-down and bottom-up interventions
Impact of the physico-chemical properties of commercial pea proteins concentrate and isolate on the quality of meat analogs
No full textInternational audiencePlant proteins extracted from soys and peas, have been identified as potential functional ingredients for plantbased meat analogs producted by high moisture extrusion cooking (HMEC). However, the extraction process (dry for concentrate and wet for isolate) can have an impact on the primary structure of the proteins, affecting their technical and functional properties. This study aims to compare the impact of two fractionation process on pea proteins (structure, fractions, flowing index) and their ability to create a network, which can mimic the fiber structure found in meat, within moisture extrusion. Pea protein concentrates (PPC) obtained by dry fractionation, and pea protein isolate (PPI) by isoelectric precipitation were characterized in terms of functional and flow properties. Results showed that PPI have a higher aggregation, lower solubility and water-holding capacity than PPC, and no thermal event was highlighted by differential scanning calorimetry, indicating proteins denaturation of PPI. Denaturation of proteins before the heating step in extruder barrel contrasts with the current model described in the literature. However, treating with HMEC, PPC is less suitable than PPI where better results in term of flow properties (respectively with flowability indexes of 27.33 and 56.17) and anisotropic structure. In that way, it appears that proteins concentration (55 % and 70 % respectively for PPC and PPI) is the most important parameter for creating a meat like texture in the conditions of the experiment