Portail "HAL-Francophonie Afrique et Océan Indien"
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Energy optimization of a dish/stirling solar system for electricity generation
No full textInternational audienceStirling cycle machines are used in both motor and receiver cycles. The Stirling cycle engine has good potential for use due to advantages such as external combustion and fuel flexibility. This study presents a Dish/Stirling system to capture solar energy for electricity generation by optimizing its energy performance. The system comprises a solar collector to convert solar energy into heat, a Stirling engine to convert heat into mechanical energy, and an alternator to convert mechanical energy into electrical energy. The Schmidt model with imperfect regeneration is used, taking into account work losses due to gas spring hysteresis. In addition, thermal losses from the solar collector are taken into account in this model. Numerical modeling was performed using MATLAB software. The impact of operational and design elements on the energy performance of the system are studied. Two objective functions were studied, namely solar electric power and solar electric energy efficiency. The results reveal that the present Dish/Stirling explores an improvement in solar electric energy efficiency of 7 % in particular in the absence of consideration of fluid friction losses. Optimum solar electric energy yield is 43.78 % at f = 18 Hz, a maximum electrical power is 10.85 kW at TE=400 K. Finally, the heat loss due to regenerator imperfections is greatest for the paraboloidal concentrator, with a value of 0.520 kW, while the smallest loss is that due to gas spring hysteresis, with a value of 0.045 kW. This system can be used for lighting in non-electrified areas
Épidémiologie des bactériémies et fongémies primaires chez les patients assistés par membrane de circulation extracorporelle (ECMO)
No full textBackground: Over the past decade, the use of ECMO has increased exponentially. Patients with ECMO support present a specific profile with systemic inflammatory response and immune alteration resulting in a higher risk of bloodstream infections. Bloodstream infections of unknown sources deserve to be further studied.Method: This retrospective, observational study was conducted in the multidisciplinary intensive care unit of the University Hospital of Reunion Island to describe the epidemiology of bloodstream infections of unknown sources during ECMO support between January 2014 and December 2022.Results: Bloodstream infections of unknown sources are associated with longer ECMO support, invasive mechanical ventilation support and ICU stay.Conclusion: Longer ECMO courses are associated with higher rates of bloodstream infections.Introduction : Les techniques d’assistances par ECMO ont connu un essor dans leur utilisation ces dernières années. La susceptibilité aux infections est augmentée du fait de nombreux phénomènes physiopathologiques. Les bactériémies et fongémies primaires (dont la porte d’entrée est non retrouvée) sous ECMO sont un enjeu peu étudié.Méthode : Il s’agissait d’une étude rétrospective et observationnelle réalisée au sein du service de réanimation polyvalente du centre hospitalier universitaire de La Réunion, ayant pour objectif de décrire l’épidémiologie des bactériémies primaires sous ECMO entre janvier 2014 et décembre 2022.Résultats : On observe chez les patients présentant une bactériémie ou fongémie primaire des durées d’assistance par ECMO, de ventilation mécanique et de séjour en réanimation plus longs. On observe également plus de thromboses de canules d’ECMO.Conclusion : Une durée d’assistance par ECMO plus longue est associée à plus de bactériémies et fongémies primaires
Développement - ancrage - dissémination des low tech : quelles stratégies de Recherche-action ?
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Analyse épidémiologique des Entérobactéries Résistantes aux Carbapénèmes (ERC) dans le Sud-Ouest de l'océan Indien
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Species introductions shift seed dispersal potential more than extinctions across 120 island plant–frugivore communities
No full textInternational audienceOceanic islands are hotspots of both species extinctions and introductions, which led to marked changes in species composition. This may disrupt key ecological interactions, such as animal-mediated seed dispersal, with potential long-term impacts on ecosystem structure and functioning. While some recent studies on individual taxa and islands report functional shifts, there has been no globally comprehensive study of how these changes vary in intensity and direction across islands. Importantly, it remains unclear how changes in traits of animal communities actually translate to ecologically relevant mismatches with native plant species. We report widespread functional remodeling of frugivore communities based on frugivory-specific traits of all native, extinct, and introduced vertebrate frugivores (birds, mammals, reptiles) from 120 islands in 22 archipelagos. There is a trend for taxonomic and functional substitution, mainly of nonvolant terrestrial mammalian omnivores replacing large-gaped flying frugivores, which caused a mismatch between gape size and seed size. This shift in seed dispersal potential risks underestimation in single-taxon studies. Overall, vertebrate introductions outnumbered extinctions both in terms of species (44 vs. 23%) and islands affected (92 vs. 76%). Moreover, introductions have driven stronger shifts in frugivore trait space compared to extinctions. However, the general patterns are modulated by substantial spatial variation and idiosyncratic functional shifts within frugivore communities on some islands. This, coupled with differences in plant seed size distributions, leads to variability in realized functional mismatches among islands. These results emphasize challenges with predicting functional responses to anthropogenic activities, while highlighting that remodeling of ecosystem interactions is a global concern
Le numérique, pharmakon pour traiter les problématiques de la Responsabilité Sociale et Sociétale des Entreprises : perceptions de salariés de l’île de La Réunion
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Flavonoids as markers in herbal medicine quality control: Current trends and analytical perspective
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616586/)International audienceFlavonoids, a ubiquitous class of plant secondary metabolites, are increasingly pivotal as chemical markers for ensuring the quality, safety, and efficacy of herbal medicines (HMs). Their broad distribution, biological activities, and detectability make them ideal for this role. This comprehensive review critically examines current trends and analytical perspectives regarding flavonoids in HM quality control. We first explore advanced quality control strategies that move beyond single-compound quantification, including chemical fingerprinting, metabolomics, network pharmacology, and the innovative concept of Q-markers. The review then provides an in-depth analysis of the analytical techniques central to flavonoid analysis, from the routine use of HPTLC and HPLC-UV to advanced hyphenated systems like UHPLC-QTOF-MS, highlighting their applications in authentication, standardization, and adulteration detection. Furthermore, we emphasize the growing importance of modern data analysis workflows, particularly the integration of chemometrics and molecular networking, for interpreting complex datasets and identifying robust, bioactivity-relevant markers. By synthesizing recent research (2017–2024), this work underscores a paradigm shift towards holistic, multi-marker approaches and data-driven methodologies. It concludes that the synergistic application of advanced analytical techniques with sophisticated data modeling is essential for the future of HM quality control, ensuring reliable and standardized herbal products for global consumers
Quelles interconnections didactiques entre les espaces formels et informels pour l'enseignement de l'anglais au sein du Master MEEF 1 degré ?
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De la solidarité alimentaire au droit à l’alimentation : cas de Jao, un rituel alimentaire des Tsimihety de Mandritsara – Madagascar
No full textInternational audienceIn light of the Universal Declaration of Human Rights, the Right to Food isan acquired Right, except that with the surge in food prices, food insecurity has neverbeen so increasing. How can we claim this Right to Food when everyone is strugglingto eat their fill? This Right cannot be understood in a narrow sense, because eatingimplies access to work, land, and resources. Tsimihety society, through the Jao foodritual, reveals much more than the beauty of social life. It reveals the source of theRight to Food and all the legal foundations of social organization inside tsimihetysociety.Résumé : Au regard de la Déclaration Universelle des Droits de l’Homme, le Droit à l’alimentation est un Droit acquis, sauf qu’avec le flambé des prix des denrées, la précarité alimentaire n’a jamais été aussi croissante. Ce Droit ne peut être saisi dans un sens étroit, car manger implique l’accès au travail, aux terres, aux ressources. La société tsimihety, à travers le rituel alimentaire de Jao, révèle bien plus que la beauté du vivre ensemble. En vérité, ce rituel révèle la source même du Droit à l’alimentation ainsi que tous les soubassements juridiques de l’organisation sociale tsimihety. Mots-clés : alimentation, Droit, lien social, justice sociale, solidarit
