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Integration of Machine Learning-Based Plasma Acceleration Simulations into Geant4: A Case Study with the PALLAS Experiment
No full textInternational audienceWe present the development and integration of a Machine Learning (ML)-based surrogate model, trained on Particle-In-Cell (PIC) simulations of laser-driven plasma wakefield acceleration source of electrons, into Geant4 simulation toolkit. Our model enables the generation and tracking of plasma-accelerated beams within complete experimental setups, unifying plasma acceleration and Monte Carlo-based simulations, which significantly reduces their complexity and computational cost. Our implementation focuses on the PALLAS laser-plasma accelerator test facility, integrating its full experimental setup into Geant4. We describe the ML model, its integration into Geant4, and key simulation results, demonstrating the feasibility of start-to-end simulations of plasma acceleration facilities and applications within a unified framework
Transitioning towards Harmonious Living: A Society-Economy-Nature model with heterogeneous agents, finite resources and politics (SEN-HARP) for Europe-27
No full textInternational audienceThe urgent need to mitigate climate change demands rapid and extensive de-carbonization of global economies. Transition to net-zero carbon is not merely technical but a complex socio-political endeavour with significant trade-offs involving inequality, well-being, sustainability, and political acceptability. If perceived as unfair, the transition risks rejection and political backlash. Still, a just and inclusive transition can also enhance social cohesion and accelerate sustainable policy adoption. In this paper, we introduce a new Agent-Based Model (ABM) called SEN-HARP which integrates biophysical and socio-political modules through original feedback loops to study how these interactions might shape the feasibility and effectiveness of different scenarios of European Union's Green Deal: market-based and innovation, augmented Green Deal, and a disruptive post-growth called “harmonious living”. SEN-HARP articulates the micro and macro levels for simulating the joint dynamics of resource use, warming impacts, livelihood dynamics and voting behaviour the latter being based on perceived gains or losses from transition policies. By combining an Agent-Based Stock-Flow Consistent (AB-SFC) approach with an environmental biophysical module, SEN-HARP can also explore how sustainability goals interact with inequality and political acceptability within fiscal and physical boundaries. While significant progress has been made in understanding the biophysical dimensions of climate change, the socio-political aspects remain largely under-explored by assessment models. This paper therefore provides a useful tool for analysing more comprehensively the trade-offs between effectiveness, fairness and political feasibility brought by the net-zero carbon transition
Camera traps unable to determine whether plasticine models of caterpillars reliably measure bird predation
No full textInternational audienceSampling methods that are both scientifically rigorous and ethical are cornerstones of any experimental biological research. Since its introduction 30 years ago, the method of using plasticine prey to quantify predation pressure has become increasingly popular in biology. However, recent studies have questioned the accuracy of the method, suggesting that misinterpretation of predator bite marks and the artificiality of the models may bias the results. Yet, bias per se might not be a methodological issue as soon as its statistical distribution in the samples is even, quantifiable, and thus correctable in quantitative analyses. In this study, we focus on avian predation of lepidopteran larvae models, which is one of the most extensively studied predator-prey interactions across diverse ecosystems worldwide. We compared bird predation on plasticine caterpillar models to that on dead caterpillars of similar size and color, using camera traps to assess actual predation events and to evaluate observer accuracy in identifying predation marks a posteriori . The question of whether plasticine models reliably measure insectivorous bird predation remained unanswered, for two reasons: (1) even the evaluation of experienced observers in the posterior assessment of predation marks on plasticine models was subjective to some extent, and (2) camera traps failed to reflect predation rates as assessed by observers, partly because they could only record evidence of bird presence rather than actual predation events. Camera traps detected more evidence of bird presence than predation clues on plasticine models, suggesting that fake prey may underestimate the foraging activity of avian insectivores. The evaluation of avian predation on real caterpillar corpses was probably also compromised by losses to other predators, likely ants. Given the uncertainties and limitations revealed by this study, and in the current absence of more effective monitoring methods, it remains simpler, more cost-effective, ethical, and reliable to keep using plasticine models to assess avian predation. However, it is important to continue developing improved monitoring technologies to better evaluate and refine these methods in order to advance research in this field
Photoelectrocatalytic response of tris(2,2′-bipyridyl)ruthenium(II)-modified mesoporous silica film on ITO electrode with methyl viologen quencher and EDTA donor
No full textInternational audienceIn the present paper, we investigate the photoelectrochemical behaviour of a tris(bipyridine) derivative (denoted [Ru(bpy)2(bpy')] 2+ ) covalently immobilized in the nanochannels of a vertically aligned mesoporous silica film (VMSF) generated by electrochemically assisted self-assembly (EASA) onto a transparent indium-tin oxide (ITO) electrode, in solutions containing a quencher (methyl viologen, MV 2+ ) and a model substrate partner (ethylenediaminetetraacetate, EDTA). The optimal film loading was first determined according to its solid-state photophysical properties. Then, the electrochemically accessible [Ru(bpy)2(bpy')] 2+ moieties were exploited in the presence of the MV 2+ quencher alone in solution (aerated medium) to demonstrate the possible electrochemical regeneration of the photocatalyst immobilized in VMSF on ITO. This was achieved on the basis of experiments carried out by hydrodynamic amperometry at constant potential under successive sequential illumination (at 400 nm) and dark periods. Finally, the functionalized film was applied to the photoelectrocatalytic oxidation of EDTA in an oxygen-free solution containing also MV 2+ species, thanks to the effective electrochemical regeneration of the quencher, as also evidenced by photocurrent measurements as a function of time with successive switching of light from 'off' to 'on' and vice versa. Such photoelectrocatalytic transformation of EDTA is possible at a much lower potential (-0.1 V) than that observed for its direct electrocatalytic oxidation by the same [Ru(bpy)2(bpy')] 2+ -functionalized film operating without light (+1.2 V).</div
Analyse descriptive des demandes de surexpertise médicale chez les candidats à l’engagement dans les armées et la Gendarmerie nationale au 12ème CMA de Bordeaux de 2019 à 2021
No full textContexte : la surexpertise médicale est une demande auprès du service de santé des armées à bénéficier d’un réexamen à la suite d’une inaptitude. Il s’agit d'une procédure de recours qui doit être initiée par le candidat à l’engagement dans les armées. Cette procédure peut conduire à demander à un médecin des armées plus qualifié d’examiner la situation et de prendre une nouvelle conclusion médico-administrative. Au 12ème CMA de Bordeaux, environ 150 demandes de surexpertise sont traitées chaque année. Méthode : nous avons mené une étude rétrospective observationnelle descriptive et monocentrique au sein du 12ème CMA. La période d’étude s’étendait du 1er janvier 2019 au 31 décembre 2021. Les objectifs étaient de décrire la typologie des demandes de surexpertise, d’analyser les délais de traitement des demandes et de discuter de la place du médecin généraliste au cours de ce processus. Résultats : 474 candidats à l’engagement ont adressé 484 demandes de surexpertise. 76% étaient des hommes. La médiane d’âge était de 20 ans. 42% désiraient s’engager dans l’armée de Terre et 49,5% souhaitaient accéder à la catégorie militaire du rang. 42% des motifs d’inaptitude concernaient une pathologie locomotrice. 30,2% des demandes de surexpertise ont été acceptées par le CMA. Parmi elles, 65% ont bénéficié d’un reclassement d’aptitude à l’issue d’une consultation spécialisée. 84% des refus de surexpertise étaient dus à un accord avec les textes réglementaires. Enfin, la durée médiane d’une demande de surexpertise était de 76 jours (surexpertises) et de 8 jours (refus de surexpertise). La demande d’examen complémentaire allongeait ces délais. Conclusion : la surexpertise permet l'engagement dans les armées d'un nombre important de candidats initialement inaptes. L'emploi de surexperts issus de la médecine des forces permettrait de réduire les délais lors d'une surexpertise. L'expertise du médecin généraliste est essentielle au cours du traitement de la demande de surexpertise
The Stochastic Light Confinement of LiquidO
No full textInternational audienceLight-based detectors have been widely used in fundamental research and industry since their inception in the 1930s. The energy particles deposit in these detectors is converted to optical signals via the Cherenkov and scintillation mechanisms that are then propagated through transparent media to photosensors placed typically on the detector's periphery, sometimes up to tens of metres away. LiquidO is a new technique pioneering the use of opaque media to stochastically confine light around each energy deposition while collecting it with an array of fibres that thread the medium. This approach preserves topological event information otherwise lost in the conventional approach, enabling real-time imaging down to the MeV scale. Our article demonstrates LiquidO's imaging principle with a ten-litre prototype, revealing successful light confinement of 90% of the detected light within a 5 cm radius sphere, using a custom opaque scintillator with a scattering length on the order of a few millimetres. These high-resolution imaging capabilities unlock opportunities in fundamental physics research and applications beyond. The absolute amount of light detected is also studied, including possible data-driven extrapolations to LiquidO-based detectors beyond prototyping limitations. Additionally, LiquidO's timing capabilities are explored through its ability to distinguish Cherenkov light from a slow scintillator
Et si l’assurance verte pouvait aider à réduire les produits phytosanitaires dans les vignobles…
No full textInternational audienceDans le cadre d’un living lab viticole aquitain, des producteurs, une compagnie d’assurance et un acteur public ont conçu une nouvelle forme d’« assurance verte ». L’objectif : permettre l’expérimentation d’un nouvel outil d’optimisation de la protection phytosanitaire des vignes, par la couverture des pertes potentielles
Petits boulots et grandes galères : être jeune sans diplôme en milieu rural
No full textInternational audienceBetween the steady decline in the school drop-out rate and the increasing importance of qualifications for professional integration, young people without qualifications face an increasingly difficult situation on the labour market. This is particularly true in rural areas, where these young people find themselves trapped in a situation of structural instability, paradoxically perpetuated by their visceral attachment to work. This Céreq Bref explores the complex dynamics of their integration, between the desire for autonomy, the rejection of the stigma associated with social benefits, and the exploitation of their availability on the labour market.Entre la baisse régulière du décrochage scolaire et la place toujours plus grande du diplôme dans l'insertion professionnelle, les jeunes non diplômés font face à une situation de plus en plus difficile sur le marché du travail. Cela est particulièrement vrai en milieu rural, où ces jeunes se voient enfermés dans une instabilité structurelle, paradoxalement entretenue par leur attachement viscéral au travail. Ce Céreq Bref explore les dynamiques complexes de leur insertion, entre aspirations à l'autonomie, rejet de la stigmatisation associée aux aides sociales, et exploitation de leur disponibilité sur le marché du travail
Vocabulary and reading skills in adults with Prader-Willi syndrome
No full textInternational audienceIntroduction: Prader-Willi syndrome (PWS) is a rare genetic condition associated with global intellectual impairment. While research has evidenced speech problems, little is known about reading, which is a critical language ability involved in communication. The aim of the present study was to investigate vocabulary and reading skills in adults with PWS.Method: A total of 56 individuals (35 females, mean age = 33.64 years, range = 19-57 years) with PWS participated. Standardized paper and pencil tests were used to examine the level of vocabulary (LexTale-FR test) and reading performance (Alouette-R test). Two computerized tasks were also administered to assess the efficiency of lexical and phonological processes in reading (lexical and phonological decision tasks, taken from the ECCLA software). Performance was analyzed and compared with available norms on neurotypical adults and/or children.Results: The results showed that adults with PWS had a low level of vocabulary (i.e., three to five standard deviations difference compared to neurotypical adults), poor reading skills (i.e., equivalent to the level of nine-year-olds), and less efficient lexical and non-lexical phonological processes.Conclusion: The present data suggest a global impairment in vocabulary and reading skills in adults with PWS. These findings might help clinicians to better understand the language abilities of these patients
Biology-Informed inverse problems for insect pests detection using pheromone sensors
No full textInternational audienceMost insects have the ability to modify the odor landscape in order to communicate with their conspecies during key phases of their life cycle such as reproduction. They release pheromones in their nearby environment, volatile compounds that are detected by insects of the same species with exceptional specificity and sensitivity. Efficient pheromone detection is then an interesting lever for insect pest management in a precision agroecological culture context. A precise and early detection of pests using pheromone sensors offers a strategy for pest management before infestation. In this paper, we develop a biology-informed inverse problem framework that leverages temporal signals from a pheromone sensor network to build insect presence maps. Prior biological knowledge is introduced in the inverse problem by the mean of a specific penalty, using population dynamics PDE residuals. We benchmark the biological-informed penalty with other regularization terms such as Tikhonov, LASSO or composite penalties in a simplified toy model. We use classical comparison criteria, such as target reconstruction error, or Jaccard distance on pest presence-absence. But we also use more task-specific criteria such as the number of informative sensors during inference. Finally, the inverse problem is solved in a realistic context of pest infestation in an agricultural landscape by the fall armyworm (Spodoptera frugiperda)