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Ground-based high-frequency sea level monitoring from multi-GNSS reflectometry using extended Kalman filtering
No full textInternational audiencethan 1 cm under all tidal, wave, current, and meteorological conditions (IOC 2006). In recent years, GLOSS has also emphasized the importance of high-frequency data acquisition at intervals of one minute or less to support tsunami warning systems and capture rapid sea level variations (IOC 2020).Traditional tide gauges and satellite altimetry play a central role in sea level monitoring (Adebisi et al. 2021), but each presents specific limitations. Tide gauges offer high temporal resolution, but remain spatially sparse, and can be vulnerable in challenging coastal environments, particularly in areas exposed to strong wave action or extreme events such as cyclones. Although satellite altimetry provides nearglobal spatial coverage approximately every 10 days, it does not offer continuous sea level measurements at specific locations, limiting its capacity to capture rapid or short-term variations. Moreover, its accuracy decreases near the coast</div
« Tout le monde déteste la Pallice » : les grandes installations portuaires comme révélatrices de la complexité des enjeux liés à l’Anthropocène sur les territoires littoraux
No full textInternational audienceExposés aux risques climatiques mais également à des conflits d’usages, les territoireslittoraux présentent des infrastructures spécifiques, révélatrices de la complexité des enjeux liés àl’Anthropocène. Nous nous intéressons ici au Grand Port Maritime de La Rochelle, de sacontribution à la transition écologique territoriale, à la mobilisation de l’été 2024 faisant le lienentre les retenues de substitution (« méga-bassines ») et le 2ème port français d’exportation decéréales. Nous notons la complexité des enjeux qui traversent ces grandes installations portuairescomme autant de résistances face à l’urgence écologique qui s’accélère. En interrogeant différentsfonds d’archives, nous tenterons par cette démarche exploratoire s’appuyant sur la méthode Gioiade mettre en lumière le rôle du Grand Port Maritime dans la dynamique de spécialisation duterritoire et de son hinterland tout entier vers la production de céréales (infrastructures et nouvellesactivités). Par ailleurs, nous nous intéresserons également à la manière dont ces infrastructures sontperçues par la population et les corps intermédiaires et ainsi découvrir si cette mobilisation de l’été2024 est épisodique ou si elle est intrinsèque à ce type de structure
Réhabiliter des figures intellectuelles oubliées. Valorisation Numérique du parcours et de l’œuvre de l’intellectuel rochelais Jean Duvignaud (1921-2007)
No full textIn 2007, the sociologist, writer, and theatre critic from La Rochelle, Jean Duvignaud, took his final leave from the stage. Little known—or not known at all—to the general public, his name has gradually faded from scientific memory. Yet, he left behind a substantial body of published work and a remarkable collection of archives, divided among several holdings located at the Municipal Archives and the University Library of La Rochelle, as well as at the Institut Mémoires de l’Édition Contemporaine (IMEC) in Caen.The works of Jean Duvignaud—like those of many other scholars who have left behind extensive yet underexplored archival and documentary resources—deserve renewed attention, as they could significantly enrich contemporary knowledge. This observation prompts reflection on the social and communicational processes that lead to the forgetting of the vast majority of twentieth-century thinkers. To address this issue, the author must first be recontextualized within his historical and socio-intellectual milieu, allowing for several avenues of interpretation.Furthermore, the relative anonymity of Duvignaud’s work and archives invites a critical examination of how contemporary private archives are treated and of their heritage value. Finally, this research proposes a digital strategy for the enhancement and mediation of the archives and works of forgotten intellectuals—through the collection, digitization, and processing of diverse documentary and bibliographical materials (such as correspondence, photographs, and out-of-print publications) for online exhibition.At the core of this project lies the fundamental principle of knowledge sharing, and thus, the commitment to open access for all collected information. Consequently, in the final stage of this work, the archival and descriptive databases will be deposited in the Nakala data repository and will be made publicly accessible through an online exhibition, partly hosted on a dedicated page of the e-c@na website, developed within the framework of the eponymous project and supported by Huma-Num.En 2007, le sociologue, écrivain et critique de théâtre rochelais Jean Duvignaud quitte la scène. Il est peu, voire pas connu du grand public, et son nom s’efface des mémoires scientifiques. Pourtant il laisse derrière lui une œuvre éditoriale conséquente et un formidable ensemble d’archives, divisé en plusieurs fonds répartis entre les Archives Municipales et la Bibliothèque universitaire de La Rochelle et l’Institut Mémoire de l’Edition Contemporaine (IMEC) à Caen.Les travaux de Jean Duvignaud, comme ceux de tant de personnalités scientifiques qui ont laissé derrière elles une manne archivistique et documentaire méconnue, gagneraient à sortir de l’ombre, et permettraient d’enrichir considérablement les connaissances actuelles. Ce constat nous amène à nous interroger sur les processus sociaux et communicationnels qui conduisent à l’oubli de l’immense majorité des penseurs du XXe siècle. Il nous faut alors resituer l’auteur dans son époque et son environnement socio intellectuel pour dégager plusieurs pistes de réponse. Ensuite, la situation d’anonymat dans laquelle se trouvent son œuvre et ses archives nous conduit à envisager de manière critique le traitement des archives privées contemporaines et leur dimension patrimoniale. Enfin, nous proposons une démarche numérique de valorisation et de médiation des archives et de l’œuvre d’intellectuel-le-s oublié-es, consistant en la collecte, la numérisation, et le traitement, à des fins d’exposition en ligne, de nombreux documents et données bibliographiques et archivistiques (correspondances, photographies, ouvrages sortis du circuit éditorial).Au fondement de ce projet se situe le principe fondamental de partage de la connaissance, et donc l’accès ouvert aux informations collectées. Alors, dans la dernière phase de ce travail, les bases de données archivistiques et descriptives seront déposées sur l’entrepôt de données Nakala, et bénéficieront d’une exposition en ligne en partie assurée par une page dédiée sur le site e-c@na, développé dans le cadre du projet éponyme, et hébergé par Huma-Num
Musées, expositions et sinologie : les nouveaux instruments du soft power chinois
No full textInternational audienceWhile many criticisms target its political system and some of its economic practices, China is multiplying initiatives to influence abroad. In France, museums, exhibitions and sinology centers play a key role in the dissemination of a peaceful and advantageous image of the country, centered on its cultural and artistic wealth as well as its ties of friendship with France that date back several centuries. Review of the main instruments of this Chinese soft power.Alors que de nombreuses critiques visent son système politique et certaines de ses pratiques économiques, la Chine multiplie les initiatives d’influence à l’étranger. En France, musées, expositions et centres de sinologie jouent un rôle clé dans la diffusion d’une image apaisée et avantageuse du pays, centrée sur sa richesse culturelle et artistique ainsi que sur ses liens d’amitié avec la France qui remontent à plusieurs siècles. Examen des principaux instruments de ce soft power chinois
Les logiques spatiales de l’installation des Océaniens en France hexagonale
No full textInternational audienceUsing a mixed quantitative and qualitative approach, based on the analysis of individual-level data from the 2020 French population census (INSEE) and on thirty semi-structured interviews, this article offers an original examination of the spatial distribution of French nationals of Oceanian origin (New Caledonia, French Polynesia, and Wallis and Futuna) residing in metropolitan France. Conducted at both departmental level and IRIS scale, the analysis culminates in a detailed case study of the Toulon area, which hosts the highest concentration of Oceanian populations in metropolitan FranceEsta investigación propone un estudio inédito sobre la distribución espacial y la residencia de las poblaciones de nacionalidad francesa procedentes de las islas del Pacífico (Nueva Caledonia, Polinesia Francesa y Wallis y Futuna) en la Francia continental. Combina la investigación cuantitativa y cualitativa trabajando los microdatos por individuo del censo de población de 2020 del INSEE para la Francia continental y, por otra parte, realizando una treintena de entrevistas semiestructuradas. El estudio, a escala departamental, se ha desarrollado a partir de las unidades estadísticas IRIS y se ha focalizado en el área de Toulon, que es la zona con mayor concentración de residentes procedente de las islas del Pacífico en la Francia continental.À partir d’une approche quantitative et qualitative, fondée d’une part sur le traitement des données individuelles du recensement de la population de 2020 de l’INSEE dans l’Hexagone, et, d’autre part, sur l’analyse d’une trentaine d’entretiens semi-directifs, nous proposons une étude inédite de la répartition spatiale des populations de nationalité française et d’origine océanienne (Nouvelle-Calédonie, Polynésie française et Wallis-et-Futuna) résidant dans l’Hexagone. Notre analyse, à l’échelle départementale et au niveau des IRIS, débouche sur l’étude de l’aire toulonnaise, lieu de la plus forte concentration d’Océaniens dans l’Hexagone
Producing a new in-situ wind speed product for the Southern Ocean based on acoustic meteorology from biologged southern elephant seals
No full textInternational audienceObtaining in-situ wind speed measurements over the Ocean is paramount to i) better calibrate numerical models and satellite imagery and ii) increase our understanding of upper ocean processes such as Mixed Layer Depth (MLD) dynamics and air–sea gas exchanges. For instance, increasing wind speeds deepen the MLD through surface turbulence and mixing. In this study, we evaluate the use of acoustic meteorology as an alternative to conventional reanalysis and scatterometer products by training regression models and Long Short-Term Memory (LSTM) neural networks on passive acoustic data recorded from biologged elephant seals. The study presents the first LSTM fine-tuned on wind speed data products from the China-France Oceanography SATellite (CFOSAT) mission, exhibiting remarkably low errors with an average error over all deployments of 0.86 m/s . Using an innovative validation protocol, by correlating wind speed predictions with co-located MLD measurement, the different models are compared. All models’ wind speed predictions exhibit better correlation coefficients with the MLD than the ERA5 re-analysis wind speed products, underscoring the added value of acoustic meteorology in resolving ocean-atmosphere coupling. This work highlights the potential of passive acoustic monitoring as a robust, scalable, and accurate tool for oceanographic and climate studies
Variation in albumin glycation rates in birds suggests resistance to relative hyperglycaemia rather than conformity to the pace of life syndrome hypothesis
No full textVersion of Record, May 19, 2025 : https://doi.org/10.7554/eLife.103205.4International audienceThe pace of life syndrome hypothesis (POLS) suggests that organisms’ life history, physiological and behavioural traits should co-evolve. In this framework, how glycaemia (i.e., blood glucose levels) and its reaction with proteins and other compounds (i.e. glycation) covary with life history traits remain relatively under-investigated, despite the well documented consequences of glucose and glycation on ageing, and therefore potentially on life history evolution. Birds are particularly relevant in this context given that they have the highest blood glucose levels within vertebrates and still higher mass-adjusted longevity when compared to organisms with similar physiology as mammals. We thus performed a comparative analysis on glucose and albumin glycation rates of 88 bird species from 22 orders, in relation to life history traits (body mass, clutch mass, maximum lifespan and developmental time) and diet. Glucose levels correlated positively with albumin glycation rates in a non-linear fashion, suggesting resistance to glycation in species with higher glucose levels. Plasma glucose levels decreased with increasing body mass but, contrary to what is predicted to the POLS hypothesis, glucose levels increased with maximum lifespan before reaching a plateau. Finally, terrestrial carnivores showed higher albumin glycation compared to omnivores despite not showing higher glucose, which we discuss may be related to additional factors as differential antioxidant levels or dietary composition in terms of fibres or polyunsaturated fatty acids. These results increase our knowledge about the diversity of glycaemia and glycation patterns across birds, pointing towards the existence of glycation resistance mechanisms within comparatively high glycaemic birds
Coastal winds are stronger and impact seabird behaviour and fitness in a warming Arctic
No full textThe Arctic is warming nearly four times faster than the rest of the planet. This unprecedented warming is profoundly altering environmental conditions. Coastal areas, which are crucial for biodiversity and human activities, are at the forefront of these changes. Among the major environmental changes expected in coastal regions are shifts in wind regimes and an increase in storm frequency. Using an interdisciplinary approach, we demonstrated that (1) wind conditions in Arctic coastal regions during summer are changing, resulting in a rise in strong wind events. (2) These large-scale changes in wind dynamics influence the movements and fitness of seabirds, with broader impacts on panarctic socio-ecosystems. To demonstrate these effects, we used a long-term study of little auks (Alle alle), the most abundant Arctic seabird species and an ecological indicator of Arctic coastal ecosystems. We showed that during strong wind events, little auks significantly reduce the visits to the colony. These behavioural changes negatively impact their fitness as inferred from chick growth rates. Overall, strong wind events disrupt the delicate balance between parental investment and self-maintenance in this long-lived species. Over time, such pressures may drive shifts in life-history traits, potentially affecting population dynamics