Portail HAL EHESS (École des hautes études en sciences sociales)
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The Unemployment‐Risk Channel in Business‐Cycle Fluctuations
No full textInternational audienceThe unemployment‐risk channel (URC) amplifies an initial contraction through a reduction in consumption demand by workers who fear unemployment. Crucial for this are the dynamics of job separations and firm hiring. In US data, the job‐finding rate responds slower to identified macroeconomic shocks than the separation rate, but accounts for a similar share of the unemployment response. We calibrate a tractable heterogeneous‐agent new‐Keynesian model with endogenous separations and sluggish vacancy creation to match these facts. The share of output fluctuations due to the URC is twice as large as in a standard model with exogenous separations and free entry
At Isturitz, environmental changes during the Aurignacian did not substantially affect human subsistance strategies
No full textInternational audienc
Wiggle and glide: fine-scale telemetry reveals unique diving strategies in benthic-foraging sea snakes
No full textInternational audienceAbstract Background The efficient acquisition of two critical but spatially separated resources –food and oxygen– governs the daily movements and diving patterns of air-breathing aquatic animals. Unlike pinnipeds, turtles and seabirds, fully marine (‘true’) sea snakes spend their entire lifecycle at sea and have evolved specialised movement behaviours. However, fine-scale data on the diving behaviour of free-ranging sea snakes remain scarce, limiting our understanding of their ecology and vulnerability to anthropogenic threats. Methods We used acoustic telemetry to track five individuals of two benthic-foraging sea snake species ( Hydrophis stokesii , H. major ) in Exmouth Gulf, Western Australia, and Baie des Citrons, New Caledonia. Each snake was continuously tracked using a directional hydrophone for up to 18 h, generating high-resolution, three-dimensional dive paths. After filtering, we analysed 106 dives from 46 h of tracking. Results Sea snakes primarily conducted U- and S-shaped dives and spent on average 97.2% of their time submerged. Most U-shaped dives were characterised by limited vertical and horizontal movement. S-shaped dives were more complex, with variable time on the seafloor and occasionally interrupted gradual ascents. Dive duration was positively correlated with post-dive surface interval, while depth and duration of the gradual ascent phase were influenced by environmental depth. We also identified distinctive, repetitive undulations (‘wiggles’) in the depth profiles of several dives completed by all three tracked H. stokesii . Conclusions These high-resolution data provide the first insights into the fine-scale diving patterns of benthic-foraging sea snakes. Like surface-foraging species, they appear to regulate air intake based on environmental depth and may be neutrally buoyant in the gradual ascent phase of S-shaped dives. We hypothesise that this phase facilitates efficient horizontal travel, despite potential increases in predation risk. The ‘wiggles’ observed in H. stokesii may have a functional role in buoyancy control, energy conservation, or foraging. Our study contributes to a deeper understanding of sea snake diving strategies, with implications for their ecology, physiology, and conservation
Allocating Communication Time in Electoral Competition
No full textPolitical campaigns influence how voters prioritize issues, which in turn impacts electoral outcomes. In this paper, we study how candidates’ communication shapes which issues prevail during the campaign, through which mechanisms, and to what extent. We develop an electoral competition model with two candidates, each endowed with exogenous platforms and characteristics. Candidates allocate strategically their communication time across two issues to maximize their expected vote shares. We find that when one candidate holds similar comparative advantages on both issues, the disadvantaged candidate communicate on a single issue to saturate the campaign with one topic and then increases the randomness of the election. The advantaged candidate has the opposite incentive and communicate on both issues, creating an asymmetry in the campaign. We show that in some cases, the campaign can become entirely centered on a single issue
Dual communication in a social network: Contributing and dedicating attention
No full textInternational audienceCommunication between individuals often involves two types of dual activities. On social media such as Facebook, for example, users produce content (posts) and pay attention to their friends' posts. These activities are dual as a user is more inclined to produce posts the more friends react to them and is more inclined to dedicate attention to a friend's posts the more numerous these posts are. This paper builds and analyzes a simple game with dual activities and dedicated attention when agents communicate through a follower-influencer network (say, X-Twitter). Equilibria can be multiple, each characterized by its attention network, which describes who pays attention to whom, resulting in a partition of cohesive subgroups who pay and receive attention from each other and do not communicate with agents in other subgroups. The stars-equilibria, where attention in each subgroup is focused on a single influencer, stand apart: activities and payoffs are high on average but unequal. Furthermore, they are the only equilibria stable to perturbations or to self-enforcing deviations from coalitions (coalition-proofness)
Musique et chant participatif a la phase aiguë d’un accident vasculaire cérébral (AVC)
No full textInternational audienceDe nombreuses études montrent l’action bénéfique de la musique dans la prise en soin de pathologies neurodégénératives ou vasculaires. En rééducation, le chant est utilisé avec les patients aphasiques non-fluents pour faciliter leur verbalisation.Depuis les années 1980, la Thérapie Mélodique et Rythmée (TMR) est l’une des méthodes de rééducation orthophonique les plus étudiées. Il s’agit d’une simplification de la prosodie française sur 2 notes (une quarte) avec un rythme précis et le support d’un schéma visuel. Cette méthode est efficace sur les capacités de communication fonctionnelle et de répétition. Pour les patients ayant une Négligence Spatiale Unilatérale Gauche (NSU), un piano numérique portatif peut être proposé : l’exploration des sons graves, situés sur la gauche du clavier, contribue à réduire la NSU. Des maracas peuvent être manipulés pour attirer l’attention vers la gauche, etc.En 2021, le projet « MUSIQ’R AVC » a été mis en place dans le service de neurologie de l’Hôpital Bichat, par le Dr Céline Guidoux, afin d’accompagner en musique le patient hospitalisé à la phase aiguë de son AVC, lors de son parcours de soins et de rééducation.Un groupe collaboratif, constitué des 2 orthophonistes du service de neurologie de Bichat (USINV-UNV), d’une orthophoniste musicienne et d’une médiatrice scientifique du CNRS et co-fondatrices du site Internet TRADAPHASIA, ont souhaité s’inscrire dans la ligne du projet MUSIC’R AVC pour proposer des moments musicaux live et participatifs aux patients hospitalisés dans ce service.En 2024-2025, nous avons proposé 32 séances musicales se déroulant dans les chambres des patients avec la possibilité d’une écoute de standards de jazz interprétés au saxophone et au cajon (percussion) et/ou du chant participatif. Patients et proches chantaient avec nous des chansons françaises avec un livret de parole à l’appui (4 chansons françaises - dont une appropriable par des non francophones - et une connue à l’international)
Invited lecture: Human and Animal Destinies Intertwined: Buddhist Rituals for Animal Rebirth in Contemporary South Korea
No full textInternational audienc
Trajetórias Transcontinentais: Circulações de Esculturas na Costa do Marfim, França, Senegal e Brasil (1900-2025)
No full textInternational audienceEm 1964, o Museu Nacional de Belas Artes do Rio de Janeiro adquiriu 101 objetos, provenientes das viagens do escritor Gasparino Damata aos atuais Nigéria, Benim, Togo e Costa do Marfim. Essa coleção constitui a maior parte do acervo de “arte africana”, composto por 111 artefatos, da instituição carioca. Vínculos de histórias culturais, políticas, econômicas e sociais, essas obras nos relembram a mobilidade crescente dos objetos produzidos no continente africano desde o final do século XIX. Essas presenças trazem perguntas quanto as suas origens, seus contextos de aquisição, suas trajetórias assim como a maneira de olhar, entender, descrever, estudar e exibir esse patrimônio. Os rastros dessas biografias são disseminados nos arquivos escritos, nas fontes orais, fotográficas e nas coleções privadas e publicas em diversos cantos do mundo. Focada nos objetos da Costa do Marfim, essa comunicação tem o objetivo de explorar trajetórias transcontinentais em contextos variados dos anos 1900 até o final da década de 1970. De Abidjan, até Paris passando por Dakar e o Rio de Janeiro, esses exemplos esclarecem os desafios da restituição do patrimônio africano, como tem sido promovido nesses últimos anos
TopUrbi and Alcedo's Dictionary: what methods and impasses in the textual and cartographic work of interpreting a historical source?: ANR TopUrbi Colloque, Toulouse, 2025
No full textInternational audiencePresentation in ANR TopUrbi colloque at Toulouse, Novembre 6, 2025
