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PIMMS: Pulsation-Informed Magnetic Mapping of Stars with Zeeman-Doppler Imaging I. Formalism and numerical tests
No full textInternational audienceContext. Magneto-asteroseismology is a novel technique allowing for more precise determinations of internal properties of magnetic pulsating stars, but requires an accurate characterisation of the surface magnetic field, not previously possible with Zeeman-Doppler Imaging (ZDI) due to the time-dependent surface velocity of pulsating stars. Aims. We aim to develop a new version of ZDI, which creates an additional surface velocity map, that includes the time-dependent velocities of surface elements due to pulsations. Methods. We present a new code, PIMMS: Pulsation-Informed Magnetic Mapping of Stars, which uses a surface-integrated line profile model that accounts for the additional Doppler shifts of local lines caused by pulsations. It is then possible to fit this model to spectropolarimetric observations, reconstructing maps of the surface brightness, magnetic field, and the velocity field due to the combination of pulsation and rotation. In this paper, we present and test PIMMS extensively, to understand its limitations and data requirements. Results. We find that PIMMS can accurately reproduce the magnetic fields and brightness distributions of realistic models of pulsating hot stars. The required number of observations is higher than that required for ZDI of a non-pulsating star due to the additional velocity map that must be disentangled from surface brightness variations. PIMMS is now ready to be applied to real stars
Bandits Multi-Bras Multi-Agent : application à la recharge intelligente des véhicules électriques sous contraintes réseau
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L'Institut Des Humanités Numériques : un outil clé pour les humanités numériques à CY Cergy Paris Université
No full textInternational audienceL’Institut Des Humanités Numériques (IDHN) a été créé au sein de l’Université de Cergy-Pontoise en 2017 (Froye et al. 2020). Il regroupe depuis 5 laboratoires des SHS et de l’informatique. Le but de l’IDHN est à la fois la promotion des outils numériques dans les SHS, et l’utilisation des SHS comme grille de lecture de résultats issus du monde digital.L’IDHN propose donc des outils numériques pour les chercheurs en SHS. Ces outils permettent par exemple de traiter automatiquement des corpus linguistiques. Des séminaires et des formations permettent aux chercheurs de s’approprier ces outils. Le dialogue avec le pôle ingénierie du laboratoire ETIS (informatique) permet aussi de développer des applications pour des besoins spécifiques, comme le projet #IDEO2017 (Longhi 2020) sur les tweets politiques. De manière réciproque, les chercheurs en SHS permettent l’analyse et valident la pertinence de nouveaux algorithmes informatiques (Ghilene et al. 2024).Pour effectuer ses tâches, l’IDHN organise d’abord des séminaires réguliers (comme le séminaire LT2D/IDHN ONuSeL ou l’école thématique annuelle de l’IDHN), permettant à ses membres d’échanger autour de thèmes généraux prédéfinis, ou de cibler des contextes d’application particuliers dans le cadre d’un projet de recherche. L’IDHN maintient ensuite des serveurs de stockage de données, de corpus et de sites webs. Il propose des moyens de calcul en particulier pour l’OCR et le Machine Learning. Il héberge et met à disposition de ses membres des logiciels d’annotation comme Doccano (Hiroki et al. 2018) ou INCEpTION (Klie et al. 2018), de traitement de corpus et thesaurus (OpenTheso) et de recherche et d’indexation (ElasticSearch, Meilisearch). Tous les logiciels sont des logiciels libres. Nous mettons aussi à disposition des liens vers des outils externes. Le lien entre l’enseignement et la recherche est assuré avec l’accueil de stagiaires issus de différentes formations de l’université.Depuis 8 ans l’IDHN est donc devenu un acteur majeur des Humanités Numériques à CY Cergy Paris Université. La création très récente de la Maison de la Recherche en SHS Annie Ernaux sur le site de Cergy va contribuer à renforcer cette dynamique.Cette communication sera l’occasion de réfléchir au rôle de cette infrastructure interdisciplinaire et inter-laboratoires à travers la présentation de réalisations concrètes permettant le partage de méthodes et la valorisation des données de la recherche
Mouvement relativiste des particules chargées dans un champ électrique, partie 2 : application aux premiers accélérateurs linéaires de particules, Van de Graaff et Linac (1935-1950)
No full textNouvel article faisant suite à la première partie (les rayons cosmiques en tant que premiers outils de physique nucléaire avant 1950) qui est en ligne ici: https://cnrs.hal.science/hal-05329933v1Nous avons présenté dans un précédent article (https://cnrs.hal.science/hal-05329933v1) quel fut l'usage des rayons (particules) cosmiques en tant qu'outil de physique nucléaire jusqu'en 1955, ayant permis d'étudier grâce aux chambres de Wilson plongées dans un champ magnétique, les particules produites par collision ou désintégration atmosphérique. Nous abordons dans cette seconde partie de niveau L2/L3 les mouvements relativistes des particules chargées dans un champ électrique avec application aux premiers accélérateurs linéaires apparus au même moment (Van de Graaff, Linac), mais de moindre énergie que les cosmiques, développés avant la création des grandes installations internationales telles celles du CERN après 1955 (non abordées ici)
Basin-scale modelling of gas generation and migration in the Amazon and Nile deep-sea fans: insights into gas hydrate formation
No full textInternational audienceThe Amazon and Nile are the world’s two largest rivers and supply sediments to deepsea fans rich in organic matter that host significant gas hydrate provinces. The two fans contain syn-sedimentary fault systems that record gravitational collapse on one or more deep detachments, as well as bottom simulating reflector (BSR) patches and seafloor fluid vents of varying style and distribution. As part of the ANR MEGA project (anr.fr/Project-ANR-22-CE01-0031), we applied numerical modeling to regional cross-sections of the Amazon and Nile deep-sea fans using TemisFlow™, in order to simulate, at basin scale, the generation and migration of both microbial and thermogenic gases into and through the gas hydrate stability zone (GHSZ). Results from the Amazon fan show that thermogenic gas is generated at depth within the fan, both beneath and above the basal shale detachment, but microbial gas dominates at shallower depths and within the GHSZ. The upward migration of microbial gas into the GHSZ and its eventual seepage at the seafloor on the upper slope is controlled by deep-rooted structures (thrust-fold anticlines), rooted on the basal detachment. Upslope of the GHSZ, in the inner extensional zone, gravity-driven extensional faults rooted in the basal detachment, along with permeable lithofacies (sands and carbonates), facilitate the migration and seepage of both thermogenic and microbial gas to seafloor. A similar ongoing study of the Nile fan will allow us to compare these findings with field observations of the gas hydrate systems on both fans
Advanced theory of mind predicts adolescents’ evaluation of source benevolence while reading
No full textInternational audienceSourcing skills support online readers' assessment of relevance by establishing the credibility of a message. But many adolescents struggle to efficiently engage in the critical evaluation of the information they read online. This study investigated the relationship between adolescents' Advanced Theory of Mind (AToM), their executive and verbal skills, and their abilities to assess specific dimensions of source reliability (i.e‥, source expertise, benevolence, and level of editorial control). Seventy-six French eighth graders completed tasks assessing their AToM, lexical quality, Working Memory (WM) updating, and sourcing abilities. The data showed a statistically significant relation between AToM and source benevolence assessment, after controlling for WM and lexical quality, suggesting that AToM plays a role in inferring the intentions of sources. However, no statistically significant relationship was found between AToM and other source attributes such as expertise or editorial control. Additionally, no association was observed between WM and AToM or sourcing. These findings highlight the importance of considering AToM in understanding adolescents' sourcing abilities and suggest the need for specific perspective-taking training to support their critical reading
Des pratiques d’écriture pour favoriser un apprentissage explicite de la compréhension et construire la figure du sujet lecteur
No full textInternational audienceThe paper focused on the teaching and use in schools of the novel L'enfant Océan (The Ocean Child) written by Jean-Claude Mourlevat and published in May 1999 by Pocket Jeunesse. The study shows how writing can be a lever for literary comprehension and reading in Cycle 3 classes. Writing practices based on literary works bring the text and its literary issues to the forefront, helping young readers develop their reading skills.La communication s’est intéressée à la didactisation et à la scolarisation du roman L'enfant Océan écrit par Jean-Claude Mourlevat et publié en mai 1999 aux éditions Pocket Jeunesse. L’étude montre comment l’écriture peut être un levier pour la compréhension et la lecture littéraire dans des classes de cycle 3. Les pratiques d’écriture autour de l’œuvre littéraire permettent de mettre au premier plan le texte et ses enjeux littéraires pour construire chez le jeune lecteur la posture du sujet lecteur
Signed Networks: theory, methods, and applications
No full textSigned networks provide a principled framework for representing systems in which interactions are not merely present or absent but qualitatively distinct: friendly or antagonistic, supportive or conflicting, excitatory or inhibitory. This polarity reshapes how we think about structure and dynamics in complex systems: a negative tie is not simply a missing positive one but a constraint that generates tension, and possibly asymmetry. Across disciplines, from sociology to neuroscience and machine learning, signed networks provide a shared language to formalise duality, balance, and opposition as integral components of system behaviour. This review provides a comprehensive and foundational summary of signed network theory. It formalises the mathematical principles of signed graphs and surveys signed-network-specific measures, including signed degree distributions, clustering, centralities, motifs, and Laplacians. It revisits balance theory, tracing its cognitive and structural formulations and their connections to frustration. Structural aspects of signed networks are examined, analysing key topics such as null models, node embeddings, sign prediction, and community detection. Subsequent sections address dynamical processes on and of signed networks, such as opinion dynamics, contagion models, and data-driven approaches for studying evolving networks. Practical challenges in constructing, inferring and validating signed data from real-world systems are also highlighted, and we offer an overview of currently available datasets. We also address common pitfalls and challenges that arise when modelling or analysing signed data. Overall, this review integrates theoretical foundations, methodological approaches, and cross-domain examples, providing a structured entry point and a reference framework for researchers interested in the study of signed networks in complex systems