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: séminaire intitulé « Accompagner et protéger les élèves en situation de vulnérabilité ». Plan national de formation
No full textintervention au séminaire plan national de formation Ministère de l'éducation nationale et de la jeuness
La semaine du bonheur à l’école par Béatrice Mabilon-Bonfils
No full textpodcast de radio et articlehttps://www.francebleu.fr/emissions/le-laboratoire-du-bonheur/107-1/le-laboratoire-du-bonheur-51?fbclid=IwAR2wVNWf6T1rqqKPXD8ZiyUdBOXdCx6mI9IhUO3RRbzXdPAvoOIYDMM2zj
PICSAR-QED: a Monte Carlo module to simulate strong-field quantum electrodynamics in particle-in-cell codes for exascale architectures
No full textInternational audienceAbstract Physical scenarios where the electromagnetic fields are so strong that quantum electrodynamics (QED) plays a substantial role are one of the frontiers of contemporary plasma physics research. Investigating those scenarios requires state-of-the-art particle-in-cell (PIC) codes able to run on top high-performance computing (HPC) machines and, at the same time, able to simulate strong-field QED processes. This work presents the PICSAR-QED library, an open-source, portable implementation of a Monte Carlo module designed to provide modern PIC codes with the capability to simulate such processes, and optimized for HPC. Detailed tests and benchmarks are carried out to validate the physical models in PICSAR-QED, to study how numerical parameters affect such models, and to demonstrate its capability to run on different architectures (CPUs and GPUs). Its integration with WarpX, a state-of-the-art PIC code designed to deliver scalable performance on upcoming exascale supercomputers, is also discussed and validated against results from the existing literature
A Call to Arms: The Day War was invented
No full textInternational audienceOne day, around 1700 B.C., a sword emerged from a bronzemaker's workshop, marking a key milestone in a never-ending arms race. A technological revolution, this invention had major consequences. The figure of the warrior emerged, and Bronze Age societies were transformed. They legitimized war and organized it both economically and politically. Western Europe in the 2nd millennium invented a specific model, a third path of civilization that was neither that of cities, nor that of the written word. Anne Lehoërff's approach to the subject of “by force of arms” raises questions about the long-term development of warfare in these oral societies, which have long been misunderstood and ignored in an intellectual history dominated by classical antiquity and the “primitives”. Our European ancestors had a different story. This book tells it
"Internationalisation et interculturalité des chercheurs, complémentarités des savoirs et des méthodologies",
No full textInternational audienc
A Study on the Sufficient Conditional and the Necessary Conditional With Chinese and French Participants
No full textInternational audienceAccording to the weak version of linguistic relativity, also called the Sapir-Whorf hypothesis, the features of an individual’s native language influence his worldview and perception. We decided to test this hypothesis on the sufficient conditional and the necessary conditional, expressed differently in Chinese and French. In Chinese, connectors for both conditionals exist and are used in everyday life, while there is only a connector for the sufficient conditional in French. A first hypothesis follows from linguistic relativity: for the necessary conditional, better logic performance is expected in Chinese participants rather than French participants. As a second hypothesis, for all participants, we expect performance on the sufficient conditional to be better than on the necessary conditional. Indeed, despite the isomorphism of the two conditionals, they differ in how information is processed for reasoning. We decided to study reasoning under uncertainty as it reflects reality more accurately. To do so, we analyzed the coherence of participants using de Finetti’s theory for deduction under uncertainty. The results of our study show no significant difference in performance between Chinese and French participants, neither on the sufficient conditional nor on the necessary conditional. Thus, our first hypothesis derived from the weak version of linguistic relativity is not confirmed. In contrast, our results confirm the second hypothesis in two out of three inference schemas
A quantitative study of the influence of cement matrix impregnation on yarn pullout strength using combined confocal microscopy and double resin impregnation
No full textInternational audienceThe complex impregnation of a multifilament yarn by a cementitious matrix leads to a difficult prediction of the mechanical behaviour of textile reinforced concrete and its less spread use than steel-reinforced concrete. To solve this prob- lem, several models were established but they are not based on direct observa- tions of the embedded yarn or quantification of its impregnation. In order to improve those models, a double resin impregnation process followed by confo- cal microscopy was set up, after pullout test was performed on each sample. Sev- eral parameters were then computed from the obtained images, which enables to quantify the impregnation ofthe yarn for each sample and to compare it with the pullout mechanical results. The number of fully impregnated filaments is found to be the crucial point to explain the pullout maximum load. The type of fail- ure is also defined using those same parameters, computed along the embedded length, and it was found that the shape of the extracted volume of yarn is cylin- drical and so the failure of the filaments is not telescopic. A pre-existing model was then improved, considering all those conclusions obtained by microscopic observations, and a good match between the numerical and the experimental results was found. Multifilament yarns are a continuous and flexible textile structure composed of hundreds of filaments that are maintain together using a chemical product called sizing. Those multifilament yarns can be used to reinforce mortar or con- crete, like steel in steel-reinforced concrete. The performances of those types of composites depend strongly on the strength of the reinforcement/mortar bond. In case of textile /mortar composite, this bond depends on the level of penetra- tion of the mortar into the yarn, so the impregnation of the yarn by the mortar. Since they are both very heterogeneous material, this impregnation is random and incomplete. Consequently, it is very difficult to predict the strength of this bond and so, the strength of the yarn/mortar composite. As a result, this type of composite cannot be widely used. Some models were established to predict the strength ofthose composite; however, they are not based on direct observation of the textile/mortar bond. To improve those models, a new visualisation method of 2 SLAMA et al.the impregnation ofthe yarn by the mortar was set up. A double moulding ofthe impregnated yarn by the mortar was manufactured, using resins and two differ- ent fluorescent dyes, after underwent a mechanical test of pulling out the yarn from the mortar (pullout test). First, a resin with a red fluorescent dye was used for the moulding ofthe yarn shortly after the test, and, second, after dissolution of the mortar around the yarn in acid, a resin with a green fluorescent dye. A num- ber of cross sections of the yarn is observed using a microscope that detects those two dyes and the obtained images are analysed allowing a clear differentiation, location and counting of fully impregnated filaments of the yarn by the mortar and those partially or not impregnated. The results are compared to the mechan- ical parameters of the pullout test. The number of fully impregnated filaments is found to be crucial to explain the strength of the composite. The behaviour dur- ing the pullout test is also explained using parameters computed along the length of the yarn in the mortar. It is found that filaments extracted by pulling-out take a cylindrical shape and so the pullout behaviour is not conical shape as it was suggested in a number of models. Considering all those conclusions obtained by observations, a pre-existing model is improved, and a good match between the numerical and experimental results is found
LPMP: A Bio-Inspired Model for Visual Localization in Challenging Environments
No full textInternational audienceAutonomous vehicles require precise and reliable self-localization to cope with dynamic environments. The field of visual place recognition (VPR) aims to solve this challenge by relying on the visual modality to recognize a place despite changes in the appearance of the perceived visual scene. In this paper, we propose to tackle the VPR problem following a neuro-cybernetic approach. To this end, the Log-Polar Max-Pi (LPMP) model is introduced. This bio-inspired neural network allows building a neural representation of the environment via an unsupervised one-shot learning. Inspired by the spatial cognition of mammals, visual information in the LPMP model are processed through two distinct pathways: a “what” pathway that extracts and learns the local visual signatures (landmarks) of a visual scene and a “where” pathway that computes their azimuth. These two pieces of information are then merged to build a visuospatial code that is characteristic of the place where the visual scene was perceived. Three main contributions are presented in this article: 1) the LPMP model is studied and compared with NetVLAD and CoHog, two state-of-the-art VPR models; 2) a test benchmark for the evaluation of VPR models according to the type of environment traveled is proposed based on the Oxford car dataset ; and 3) the impact of the use of a novel detector leading to an uneven paving of an environment is evaluated in terms of the localization performance and compared to a regular paving. Our experiments show that the LPMP model can achieve comparable or better localization performance than NetVLAD and CoHog
Dense Molecular Clouds in the Crab Supernova Remnant
No full textInternational audienceMolecular emission was imaged with ALMA from numerous components near and within bright H 2-emitting knots and absorbing dust globules in the Crab Nebula. These observations provide a critical test of how energetic photons and particles produced in a young supernova remnant interact with gas, cleanly differentiating between competing models. The four fields targeted show contrasting properties but within them, seventeen distinct molecular clouds are identified with CO emission; a few also show emission from HCO + , SiO, and/or SO. These observations are compared with Cloudy models of these knots. It has been suggested that the Crab filaments present an exotic environment in which H 2 emission comes from a mostly neutral zone probably heated by cosmic rays produced in the supernova surrounding a cool core of molecular gas. Our model is consistent with the observed CO J = 3 − 2 line strength. These molecular line emitting knots in the Crab Nebula present a novel phase of the ISM representative of many important astrophysical environments
Léman express : un nouveau service ferroviaire pour le Grand Genève
No full textInternational audienceOpérationnel depuis fin 2019, un nouveau service régional ferroviaire cadencé dessert Genève, le Canton de Vaud mais surtout Annemasse et les départements français limitrophes (Ain, Haute-Savoie). Ce service offre une alternative modale crédible pour répondre à la forte demande de mobilité pendulaire des Français travaillant à Genève… et aux dommages environnementaux qui en résultent. Le Léman Express pourra-t-il répondre à ce défi d’une forte croissance des mobilités? Permettra-t-il de repositionner Genève comme une grande métropole européenne