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Analyser l'impact de l’alerte et de l’intervention des secours sur les comportements humains en situation de catastrophe : une contribution théorique
No full textInternational audienceFace à une catastrophe, les populations sont confrontées à des situations inédites qui mettent en péril leur sécurité. Tandis que certains individus parviennent à réguler leurs émotions et à agir de manière raisonnée, d'autres, en proie à un état de stress trop intense, répété ou prolongé voient leurs capacités d’adaptation dépassées (Chidiac & Crocq, 2010). Ils développent alors des comportements inadaptés tels que la stupeur, l'agitation ou la fuite panique qui constituent des formes de panique redoutées par les gestionnaires de crise. Plusieurs facteurs peuvent influencer la façon dont les individus réagissent lors d’une catastrophe. Au-delà de l'intensité, de la fréquence, de la temporalité et de la spatialité de l'événement et des profils des personnes affectées, des facteurs tels que l'éducation, la culture du risque ou la préparation peuvent jouer un rôle crucial dans le bilan humain de la catastrophe (Lanza et al., 2023). La gestion de la crise est également déterminante, non seulement en termes d’assistance aux populations impactées, mais aussi d’alerte et d’information de celles-ci. Cependant, l'efficacité de ces actions varie considérablement en fonction de la rapidité de leur déploiement. Cette communication propose une réflexion théorique sur la temporalité de mise en œuvre de deux facteurs clés dans la gestion de la crise face à un évènement soudain : la diffusion d'informations auprès de la population impactée par le biais d'un système d'alerte massive (Douvinet et al., 2022) et l'intervention plus localisée, mais souvent plus rapide des forces de police et des secours. Notre analyse s'appuie sur un modèle dynamique à compartiments, le modèle Alerte-Panique-Contrôle (APC), qui permet de simuler la diversité et l'évolution des comportements humains pendant une catastrophe (Lanza et al., 2022; Provitolo et al., 2015; Verdière et al., 2021). Inspiré des modèles en épidémiologie, le modèle APC permet de simuler différents scénarios où la population peut évoluer entre trois types d'états comportementaux appelés Alerte (prise de conscience du danger), Contrôle (mise à l’abris, évacuation, entraide, etc.) et Panique (agitation désordonnée, fuite en panique, etc.). Ce modèle permet également de déterminer, d’un point de vue théorique, la période optimale pour mettre en œuvre ces deux solutions en fonction du profil des populations afin de minimiser l'apparition de comportements de panique (Verdière et al., 2023). Cette communication vise à confronter les résultats obtenus avec les connaissances empiriques des acteurs institutionnels, opérationnels et chercheurs spécialisés dans la gestion de crise et des secours qui seront présents au colloque.Chidiac, N., & Crocq, L. (2010). Le psychotrauma. II. La réaction immédiate et la période post-immédiate. Annales MédicoPsychologiques, Revue Psychiatrique, 168(8), 639–644. https://doi.org/10.1016/J.AMP.2010.07.011 Douvinet, J., Cavalière, C., Bopp, E., Weiss, K., Emsellen, K., Gisclard, B., Martin, G., & Coulon, M. (2022). Évaluer la perception de notifications d’alerte scénarisées dans différents contextes en France : enjeux et perspectives. Cybergeo, 1–32. https://doi.org/10.4000/cybergeo.39454 Lanza, V., Dubos-Paillard, E., Charrier, R., Provitolo, D., & Berred, A. (2022). An analysis of the effects of territory properties on population behaviors and evacuation management during disasters using coupled dynamical systems. Applied Network Science, 7(1). https://doi.org/10.1007/s41109-022-00450-6 Lanza, V., Provitolo, D., Verdière, N., Bertelle, C., Dubos-Paillard, E., Navarro, O., Charrier, R., Mikiela, I., Aziz-Alaoui, M., Boudoukha, A. H., Tricot, A., Schleyer-Lindenmann, A., Berred, A., Haule, S., & Tric, E. (2023). Modeling and Analysis of the Impact of Risk Culture on Human Behavior during a Catastrophic Event. Sustainability (Switzerland), 15(14), 1– 27. https://doi.org/10.3390/su151411063 Provitolo, D., Dubos-Paillard, E., Verdiere, N., Lanza, V., Charrier, R., Bertelle, C., & Aziz-Alaoui, M. . (2015). Human behaviors in the face of disasters: From observing to conceptual and mathematical modeling. CyberGeo, 2015. https://doi.org/10.4000/cybergeo.27150 Verdière, N., Dubos-Paillard, E., Lanza, V., Provitolo, D., Charrier, R., Bertelle, C., Berred, A., Tricot, A., & Aziz-Alaoui, M. (2023). Study of the Effect of Rescuers and the Use of a Massive Alarm in a Population in a Disaster Situation. Sustainability (Switzerland), 15(12), 1–23. https://doi.org/10.3390/su15129474 Verdière, N., Navarro, O., Naud, A., Berred, A., & Provitolo, D. (2021). Towards parameter identification of a behavioral model from a virtual reality experiment. Mathematics, 9(24), 1–25. https://doi.org/10.3390/math924317
Integrated Petrology, Geochronology and 3D Microstructural Analysis of Garnetiferous Micaschists: Insights Into the Tectono‐Metamorphic Evolution of the Betic Cordillera
No full textInternational audienceABSTRACT Integration of microstructural, petrological and geochronological techniques has allowed detailed characterization of the timing and metamorphic features of deformation events in the Betic Cordillera. Phase equilibrium modelling, thermobarometric estimations, in situ U–Pb monazite geochronology and Ar–Ar geochronology (amphibole and micas) have been applied to key samples containing well‐constrained deformation fabrics and garnet porphyroblasts of different timing that can be distinguished based on their specifically orientated inclusion trails. Our study helps constrain the timing and kinematics of initial crustal thickening stages in the Alpujárride complex, followed by orogenic collapse and renewed continental collision around 17 Ma. In the underlying Nevado‐Filábride complex, multiple garnet generations coexisting in a single investigated sample record a similar history ending with garnet growth under low‐pressure/high‐temperature conditions around 13 Ma. New age constraints for microstructural trends fossilized within porphyroblasts refine the sequence of changing shortening directions previously linked to the plate‐motion interplay between the Alborán Domain, Iberia and Africa from Eocene to Middle Miocene
Ancient genomics and the origin, dispersal, and development of domestic sheep
No full textInternational audienceThe origins and prehistory of domestic sheep ( Ovis aries ) are incompletely understood; to address this, we generated data from 118 ancient genomes spanning 12,000 years sampled from across Eurasia. Genomes from Central Türkiye ~8000 BCE are genetically proximal to the domestic origins of sheep but do not fully explain the ancestry of later populations, suggesting a mosaic of wild ancestries. Genomic signatures indicate selection by ancient herders for pigmentation patterns, hornedness, and growth rate. Although the first European sheep flocks derive from Türkiye, in a notable parallel with ancient human genome discoveries, we detected a major influx of Western steppe–related ancestry in the Bronze Age
Editorial on Special Collection in Contact : Lipid Transfer Proteins: From Molecular Mechanisms to Functional Validation
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On Kernel's Safety in the Spectre Era (Extended Version)
No full textInternational audienceThe efficacy of address space layout randomization has been formally demonstrated in a shared-memory model by Abadi et al., contingent on specific assumptions about victim programs. However, modern operating systems, implementing layout randomization in the kernel, diverge from these assumptions and operate on a separate memory model with communication through system calls. In this work, we relax Abadi et al.'s language assumptions while demonstrating that layout randomization offers a comparable safety guarantee in a system with memory separation. However, in practice, speculative execution and side-channels are recognized threats to layout randomization. We show that kernel safety cannot be restored for attackers capable of using side-channels and speculative execution, and introduce enforcement mechanisms that can guarantee speculative kernel safety for safe system calls in the Spectre era. We show that kernel safety cannot be restored for attackers capable of using side-channels and speculative execution, and introduce enforcement mechanisms that can guarantee speculative kernel safety for safe system calls in the Spectre era. We implement three suitable mechanisms and we evaluate their performance overhead on the Linux kernel
Maximizing cycling efficiency: innovative bicycle drive mechanisms tailored to individual muscular capacities
No full textInternational audienceThis study explores the customization and optimization of three distinct bicycle drive mechanisms, leveraging an individual's biomechanical data to maximize pedaling power throughput. Our approach utilizes torque/velocity/position relationships of the hip and the knee, so that the kinematics of the optimized designs allow the user to pedal with maximized joint torques and thus, enhance the power produced at the crank. The method is applied to the cases of two users with significantly distinct anthropometries, showing noticeable changes in the drive mechanisms and demonstrating its effectiveness for personalizing bicycle designs. The study highlights the importance of considering individual biomechanical factors, showing that even slight variations in design can lead to changes in the cycling kinematics, resulting in improved performance. Simulation results also show increased mean power throughput for more complex drive mechanisms compared to a classical one, regardless of the user profile. This suggests that such designs should be capable of accommodating a range of cyclists, from recreational users to high-performance athletes, as well as individuals and athletes with motor impairments. These findings underline the potential of biomechanically-informed personalized bicycle drive mechanisms to optimize pedaling efficiency and enhance performance across diverse user groups
Habitat et habitude dans le paysage
No full textInternational audiencePar un bref parcours dans la poésie de Philippe Jaccottet, et par des incursions dans celles de Lorand Gaspar et James Sacré -trois oeuvres contemporaines dans lesquelles l'immersion dans les espaces naturels est centrale -, cet article vise à montrer que l'habitat se construit par l'habitude, en opposant au passage dans l'espace, la répétition. Mots-clés : poésie ; paysage ; habiter ; corps ; mouvement Depuis les années 1950, et a fortiori depuis le tournant spatial et lyrique des années 1980, la poésie contemporaine manifeste le « désir d'une habitation de la terre et du monde qui soit séjour plus ''authentique'' 1 ». On sait ce que cette proposition de Jean-Claude Pinson doit à Martin Heidegger qui, à partir d'une lecture de Hölderlin, a invité à concevoir l'habitation comme « le trait fondamental de la condition humaine 2 », et la poésie comme « le "faire habiter'' originel 3 ». Qu'est-ce qu'habiter sinon avoir sa demeure dans un lieu, un espace habituellement choisi ? Le désir poétique contemporain traverse les murs circonscrits de la maison pour s'établir dans l'espace extérieur, le monde. Il se traduit par un retour à la nature, aux choses sensibles, aux figures de l'altérité et, de manière plus spécifique, par l'élection du paysage « comme un motif privilégié et comme un lieu de vie et de travail 4 ». Habiter revient donc, pour une partie de la poésie contemporaine, à susciter dans le monde réel, et à révéler dans la page, la rencontre d'un corps et d'un espace rendu familier par un contact assidu. Il s'agit, autrement dit, de refuser les distances, de défier l'extériorité, d'apprivoiser l'étrange dehors du monde pour s'enraciner tout entier en lui, comme le traduit ici Philippe Jaccottet :Ne pas voir cela du dehors. Ce ne peut être un spectacle, c'est ce qui est réellement vécu, traversé, le secret où l'on habite, auquel on ne peut être extérieur. Quand on est dans le corps, au coeur du monde -non plus un regard, même quand on regarde, le regard est pris dedans. Prisonnier, alors seulement on vit, non pas quand on est détaché 5 .</p
Quasi-Thermal Noise Spectroscopy in Magnetized Space Plasma: Theory and Model
No full textCaSciModOT federation at the Centre deCalcul Scientifique in the Centre‐Val deLoire region, France.International audienceThe quasi-thermal noise measured by an electric antenna is routinely used to characterize space plasmas, mainly measuring the electrons' properties. To employ this diagnostic technique, instrumental models are required to turn the instrumental output into physically meaningful measurements. Such models have been developed mainly under the assumption that no magnetic field is present in the plasma. This limit case is not met in planetary magnetospheres, for example, Earth, Mercury. The latter is the objective of the European Space Agency/Japan Aerospace Exploration Agency BepiColombo mission, that has a dedicated quasi-thermal noise experiment. The aim of this work is to extend the current state-of-the-art in quasi-thermal noise modeling by taking into account the magnetic field, therefore providing a plasma diagnostic in this magnetized regime. To achieve this goal, we developed a model for the quasi-thermal noise in a magnetized plasma. We explore four cases: for a Maxwellian and double Maxwellian electron distributions, both in the collisionless limit and in the presence of weak electron-neutral collisions. Our model is validated against known behaviors of the magnetized quasi-thermal noise spectrum, including: the characteristic frequency of maxima and minima, the modulation from the antenna spinning around the magnetic field, the electron temperature(s) influence. We explored parameter ranges that were not accessible to previous quasi-thermal noise models, in particular the high magnetization regime. The model we developed will enable using quasi-thermal noise experiments for the diagnostic of magnetospheric space plasmas, including but not limited to the Hermean and terrestrial magnetospheres, with foreseen applications to future space missions
VEM fully discrete Nitsche's discretization of Coulomb frictional contact-mechanics for mixed-dimensional poromechanical models
No full textThe simulation of poromechanical models in fractured (or faulted) porous rocks plays an important role in many subsurface applications such as fault reactivation by fluid injection in geological storages or the hydraulic fracture stimulation in deep geothermal systems. One of the key difficulties in simulating such models is the discretization of the contact-mechanical model which must be adapted to geological polytopal meshes and to the complex geometry of fracture/fault networks including tips, corners and intersections. In this work, we extend the first-order Virtual Element Method (VEM) combined with Nitsche's formulation, originally introduced in [22] for the frictionless case, to address Coulomb frictional contact. The proposed Nitsche's formulation accounts for normal compliance and its no-penetration limit in a unified way. We first investigate the well-posedness and convergence of this VEM-Nitsche discretization and discuss its robustness with respect to the normal stiffness parameter. Then, the VEM-Nitsche scheme is compared to the VEM mixed formulation with face bubble stabilization introduced in [16] on several mixed-dimensional poromechanical test cases with 2D and 3D fracture networks, including a fluid-induced fault reactivation test case.</div
Euclid Quick Data Release (Q1). The active galaxies of Euclid
No full textInternational audienceWe present a catalogue of candidate active galactic nuclei (AGN) in the Quick Release (Q1) fields. For each source we collect multi-wavelength photometry and spectroscopy information from Galaxy Evolution Explorer (GALEX), , Dark Energy Survey (DES), Wise-field Infrared Survey Explorer (WISE), , Dark Energy Survey (DESI), and Sloan Digital Sky Survey (SDSS), including spectroscopic redshift from public compilations. We investigate the AGN contents of the Q1 fields by applying selection criteria using colours and WISE-AllWISE cuts finding respectively 292,222 and 65,131 candidates. We also create a high-purity QSO catalogue based on DR3 information containing 1971 candidates. Furthermore, we utilise the collected spectroscopic information from DESI to perform broad-line and narrow-line AGN selections, leading to a total of 4392 AGN candidates in the Q1 field. We investigate and refine the Q1 probabilistic random forest QSO population, selecting a total of 180,666 candidates. Additionally, we perform SED fitting on a subset of sources with available , and by utilizing the derived AGN fraction, we identify a total of 7766 AGN candidates. We discuss purity and completeness of the selections and define two new colour selection criteria (_ and _) to improve on purity, finding 313,714 and 267,513 candidates respectively in the Q1 data. We find a total of 229,779 AGN candidates equivalent to an AGN surface density of 3641 deg for , and a subsample of 30,422 candidates corresponding to an AGN surface density of 482 deg when limiting the depth to . The surface density of AGN recovered from this work is in line with predictions based on the AGN X-ray luminosity functions