HAL Portal UPF (Université de la Polynésie française)
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Place de la TEP-FDG dans les rhumatismes inflammatoires chroniques : une revue clinique et imagerie croisée
No full textInternational audienceLa TEP au [18F]FDG est de plus en plus employée comme outil diagnostique et de suivi dans les maladies inflammatoires chroniques, notamment les rhumatismes inflammatoires. Cet article présente une synthèse des principales indications et limites de la TEP dans ce contexte, en s’appuyant sur une session conjointe entre un clinicien et un médecin nucléaire. Chaque entité nosologique (polyarthrite rhumatoïde, spondyloarthrites, rhumatismes microcristallins, pseudo-polyarthrite rhizomélique [PPR]) est abordée sous l’angle de sa présentation clinique, des enjeux diagnostiques et des apports potentiels de l’imagerie TEP. L’analyse met en évidence la valeur ajoutée de la TEP dans la PPR, notamment pour le diagnostic différentiel et la stratification des patients, ainsi que les scores d’interprétation développés récemment. En revanche, les données restent non concluantes pour la PR et SPA et limitées pour les rhumatismes microcristallins. L’article se conclut sur les perspectives offertes par de nouveaux traceurs et une intégration plus fine des données cliniques et d’imagerie
La Passion-Clipperton Atoll in the Eastern North Pacific: Anthropogenic Traces Revealing Environmental and Societal Dynamics
No full textInternational audienceClipperton or Passion Island is a French possession, located in the north-eastern Pacific Ocean. Uninhabited since 1945, the atoll is considered the most isolated in the world. In addition to a few plant and animal species that thrive there, the island has large colonies of seabirds, land crabs and recently rats, which are engaged in an interspecific struggle. In addition, Clipperton's EEZ provides a significant resource of fish and polymetallic nodules. A scientific expedition studied the remains present on the coral crown: from Mexican remains from phosphate mining, to those abandoned by the American army, to wrecks of fishing boats, to the numerous pieces of waste transported by marine currents. The problem of such remains is thus considered not only as a reverse side of production, but also as a research object combining historical, geographical, economic, geopolitical, landscape and symbolic dimensions. Indeed, the island of Clipperton, currently free of human settlement and occupation, is nevertheless subject to anthropic interactions. In addition to the fact that its location gives it a geostrategic interest for the French State, the island constitutes an in situ and in vivo laboratory, for long-term scientific study.</div
Edible seaweeds of French Polynesia: a first review and new insights into the nutritional value and safety of four Tahitian species
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Marine animal forest formed by gorgonians Subergorgia on near‐shore mesophotic ecosystems in Reunion Island
No full textInternational audienceMesophotic coral ecosystems (MCEs), occurring between 30 and 150 m depth, are increasingly recognized for their ecological importance, yet they remain underexplored, particularly in the southwestern Indian Ocean. During benthic surveys conducted at depths ranging from 15 to 75 m off northwestern Reunion Island, we documented a dense and extensive marine animal forest (MAF) dominated by large arborescent octocorals Subergorgia cf. suberosa . This monospecific community formed a complex three‐dimensional habitat spanning a substantial area at mesophotic depths over the northwestern abrupt slopes of Reunion Island. Colonies reached over 1.5 m in height, providing structural habitat for diverse fish and macroinvertebrate assemblages. A total of 53 fish species from 22 families were recorded in association with this MAF, alongside numerous epibionts and understory anthozoans. Despite its ecological value, this habitat faces significant anthropogenic pressures, particularly from fishing activities. Nearly 25% of photographed S . cf. suberosa colonies were entangled in fishing lines, with visible damage including tissue necrosis and polyp loss affecting up to 47% of colonies. These impacts, along with sedimentation from runoff, raise concerns for the long‐term persistence of this mesophotic habitat‐forming community, as long‐lived, slow‐growing organisms like gorgonians may be more impacted by these types of disturbances and take longer to recover than fast‐growing organisms. Our findings represent the first quantitative assessment of Subergorgia dominance and associated biodiversity in this region and highlight its role as a potential refuge for shallow reef taxa. The ecological significance, spatial extent, and fragility of this MAF underscore the urgent need for spatially replicated surveys, targeted conservation strategies, and regulation of damaging activities such as fishing. We advocate for increased research efforts focused on mesophotic habitats, with particular attention to the population dynamics and ecological functions of large gorgonians, to better understand the role of MCEs in reef resilience under accelerating environmental changes
Snapshots of Coral Reef Biodiversity
No full textInternational audienceCoral reefs are sanctuaries for a large portion of our planet’s biodiversity, but their rapid decline begs critical questions about what exactly is being lost, what driving forces determine decline or resilience, and what implications for life on Earth. To help address these questions, this chapter synthesizes the state of knowledge on the diversity of coral reef life forms at different scales of biological and ecological organization, encompassing variability in genes, biomolecules, cells, organs, organisms, populations, communities, ecosystems, socio-ecosystems, and biogeoclimatic systems, with a particular focus on French tropical overseas. We discuss research pathways to address knowledge gaps in various scientific disciplines, covering genetics (genomics, transcriptomics, proteomics, metabolomics), morphology, ethology, bioacoustics, demography, functional ecology, macro-ecology, landscape ecology, human and social sciences, bioclimatology, and their cross-disciplinary interactions. Based on contributions from coral reef experts working in different coral reef regions around the world, our synthesis supports a better understanding of the various dimensions of coral reef biodiversity and proposes future research orientations for improving knowledge and conservation. Given the rapid disappearance of coral reefs and how much is still unknown, this chapter underscores the urgency of cross-scale biodiversity assessments for a systemic understanding of the distribution and dynamics of biodiversity
“Denuclearizing the Pacific means Defrenchifying it”: the CEP, a Contradictory Form of French Imperialism in Oceania
No full textInternational audience“Denuclearizing the Pacific is Defrancizing It”: this quote attributed to Régis Debray (J. Chesneaux, N. Maclellan, 1992) aptly captures the paradox of a French imperialism that does not name itself, integrating French Polynesia in the name of nuclear power, which in turn sparks resistance to the nuclearization of the region. This fuels an anti-French regional reflex and bolsters local opposition to French sovereignty. This is the paradox we aim to explore, one based on a double denial: the denial of Western imperialism in the region and the denial of the health and environmental hazards resulting from nuclear testing. The imperial denial shared by the three democracies – France, Britain, and the United States – seems to be a common factor in their use of the Pacific for nuclear testing. In each case, metropolitan powers exploit politically subordinated territorial margins and implement a form of “nuclear imperialism”, as defined by Christopher Hill (2018): a metropolitan state wields its power to establish testing sites in distant territories under its control, which serve its needs and bear its risks, without having a choice in the matter. The paradox of establishing the Centre d’expérimentation du Pacifique (CEP) from 1962 to 1966, followed by nuclear tests from 1966 to 1996, lies in the fact that this move coincides with the end of the French Empire, which required relocating installations from the Sahara. How should we characterize this period in French Polynesia, which unfolded alongside the decolonization era? And how does it fit within the broader framework of U.S. and British nuclear test sites, when the United States operated outside a formal imperial framework but exploited islands within the British Empire? This new imperial repertoire compels us to confront the issue of nuclear colonialism
Essais nucléaires, sciences environnementales et « front pionnier », reflets de l’impérialisme nucléaire dans le Pacifique (1962-1996)
No full textInternational audienceEn 1962, le général de Gaulle décide de transférer les sites d’essais nucléaires du Sahara Algérien en Polynésie française. L’installation du Centre d’expérimentation du Pacifique (CEP) a lieu entre 1963 et 1966, et 193 essais nucléaires sont réalisés de 1966 à 1996. La construction du CEP reflète, en filigrane, l’impérialisme et le colonialisme nucléaire de la France dans le Pacifique : choix de sites isolés et peu peuplés, contacts asymétriques avec les populations locales, projection de la puissance militaire dans un « front pionnier », dissimulation des impacts sanitaires et environnementaux des tirs, étouffement des contestations ; tout cela au nom de la maîtrise de l’atome militaire, signe d’une avancée technologique significative malgré les nombreux impacts de l’installation du CEP et des essais nucléaires sur la Polynésie française. Ces phénomènes rappellent certains traits de la « situation coloniale » (R. Balandier, 2001). Grâce aux archives régaliennes françaises du Service historique de la défense de Vincennes, du Centre des archives diplomatiques de La Courneuve, des Archives nationales et du Commissariat à l’énergie atomique (CEA) déclassifiées en 2021, et de quelques documents britanniques et américains, cette communication, qui se place dans l’axe 5 du colloque, propose d’examiner la manière dont les acteurs du CEP et du CEA s’approprient et utilisent l’environnement et les milieux naturels pour construire à la fois la science nucléaire et les sites pour réaliser les essais et en comprendre les effets sur les êtres vivants dans ce qu’ils considèrent comme un « front pionnier ». Le déploiement d’experts, qu’ils soient civils ou militaires, inaugure une sorte d’aventure scientifique dans un espace considéré comme isolé. Cette communication se situe à la croisée de nouvelles recherches en France et de travaux réalisées par les chercheurs américains et britanniques, au regard de sources archivistiques, orales et audiovisuelles inédites. La tension entre recherche scientifique sur l’atome militaire par le biais des sciences environnementales (météorologie, climat, régime des vents, courants marins, migrations des animaux marins) et absence de préoccupations des impacts du CEP sur les milieux naturels (constructions d’infrastructures, explosions nucléaires) constitue l’ossature de la communication. Celle-ci propose comme fil conducteur, de manière chronologique (implantation, 1962-1966 ; essais atmosphériques, 1966-1974 ; tirs souterrains, 1975-1996) une grille d’analyse des déclinaisons et évolutions de l’impérialisme et du colonialisme nucléaire français dans le Pacifique, à la croisée de l’histoire politique, environnementale et scientifique selon une approche internationale et transnationale
Rôle clé de l'Oscillation de Madden-Julian sur les canicules humides
No full textVersion 1 of manuscript submitted to Nature Communications the 25/07/2024Version 2 of manuscript submitted to Journal of Climate the 19/08/2025 (under review)Humid heat stress and heatwaves pose significant risks for living organisms, from humans and wildlife to insects, with wide-ranging health, ecological, and socio-economic impacts that are expected to worsen with climate change. How large-scale climate modes drive the week-to-month variability of humid heat remains poorly understood at the global scale, hindering accurate forecasts necessary for risk-management measures, notably in the heavily populated and ecologically fragile regions of the tropics and subtropics. With forecast lead times up to several weeks, the Madden-Julian Oscillation (MJO), a global-scale intraseasonal tropical atmospheric wave circumnavigating Earth in around 30-60 days, provides considerable predictability for weather conditions, and meteorological and oceanic extremes. Here we show that the MJO, and the associated boreal summer intraseasonal oscillation (BSISO), have a significant influence on humid heatwaves over much of the tropics and subtropics across all seasons, both over terrestrial and marine regions. Humid heatwave likelihood can double or halve, depending on the MJO phase, in large areas of the Earth. The MJO/BSISO’s influence on wet-bulb temperature is primarily via specific humidity rather than dry-bulb temperature anomalies. We find that specific humidity anomalies are influenced by horizontal advection of moisture in the planetary boundary layer, particularly in the subtropics where advection of the climatological moisture gradient by MJO-related anomalous winds is the dominant term
Quel prêt à taux zéro prochainement mis en place à Tahiti ?
No full textArticle de vulgarisation scientifiqueAmong the tax measures currently under consideration by the government is the zero-interest loan. While the idea of a ‘zero rate’ immediately suggests attractive prospects for borrowers, what can we really expect from the introduction of this scheme in French Polynesia? The full article is available in French at the following link:https://www.pacific-pirates-media.com/quel-pret-a-taux-zero-prochainement-mis-en-place-a-tahiti/Parmi les mesures fiscales qui sont actuellement à l’étude par le gouvernement, on trouve le prêt à taux zéro. Si la notion de « taux zéro » évoque immédiatement des perspectives intéressantes pour les emprunteurs, que peut-on vraiment attendre de l’introduction de ce dispositif en Polynésie française ?L'article complet est disponible en français sur le lien suivant :https://www.pacific-pirates-media.com/quel-pret-a-taux-zero-prochainement-mis-en-place-a-tahiti