HAL Réunion (Univ- de la Réunion )
Not a member yet
21812 research outputs found
Sort by
Les enjeux de la régulation des médias et de la diversité culturelle dans un contexte d'hégémonie numérique : le cas du Cameroun
No full textInternational audienc
El barrenador americano de la mazorca de cacao, <i>Carmenta foraseminis</i>, una plaga emergente del cacao: una revisión
No full textA Spanish translation is available in the Supporting Information online.International audience1. This review provides a synthesis of the available knowledge on Carmenta foraseminis, an emerging cocoa pest in northern South America. 2. This moth was first described in 1995 in Panama, and its proliferation across the Amazon basin is currently threatening the production of cocoa in the region and may endanger the sector's sustainability. Hence, it is important to further draw the attention of researchers towards this emerging pest. The larvae of this lepidopteran burrow within the pod and feed on beans and their pulp, causing important losses. 3. We present a critical synthesis of the knowledge on C. foraseminis (biology, geographic distribution, phylogenetic status, ecology), to identify the cause of its emergence and key points for its control. 4. We also describe similarities to another lepidopteran, the Cocoa Pod Borer (CPB) Conopomorpha cramerella, which is the main pest of cocoa in Asia, especially on the way it is controlled and eventual lessons and recommendations that can be drawn from the situation in Asia to better understand and manage cocoa pod infestation in the Amazon basin. 5. Additionally, we propose further research themes to be explored for Carmenta foraseminis that will help in the development of efficient management practices
Prévision énergétique en milieu tropical insulaire : une taxonomie opérationnelle pour une précision robuste à faible coût computationnel
No full textTropical island territories like Reunion face significant reliance on fossil fuels and vulnerability to extreme climate events. Accurate energy forecasting—both consumption and renewable generation—is crucial to enhance grid stability and support a sustainable energy transition. Traditional methods, such as deterministic physical models, struggle to capture complex tropical climate dynamics, while purely data-driven models are computationally intensive and heavily dependent on extensive data, which is often incomplete in island contexts.This paper proposes a novel hybrid approach structured in three complementary layers: (1) a physical model based on thermodynamic principles tailored to tropical climates; (2) a statistical layer employing models like ARIMA, SARIMA, GARCH, and SARIMAX to handle trends, seasonal effects, and volatility; and (3) an optimized neural layer (compressed LSTM networks) to capture residual nonlinear dynamics. Techniques like pruning, quantization, and federated learning further reduce computational demands and energy usage.Applied to real-world data from five university buildings in La Réunion, this hybrid method demonstrated significantly improved forecasting precision with minimized computational costs. The results showed a 30% accuracy improvement during extreme weather events and a 45% reduction in computational requirements compared to traditional approaches.Future work includes automated model recalibration, further optimization for managing peak loads during climatic extremes, and broader deployment across island microgrids. Ultimately, this approach offers a practical, computationally efficient solution for enhancing renewable energy integration and resilience in tropical island settings.Les territoires insulaires tropicaux, tels que La Réunion, affrontent une forte dépendance aux énergies fossiles et une vulnérabilité aux aléas climatiques extrêmes. Dans ce contexte, la prévision énergétiquecouvrant à la fois la consommation des bâtiments et la production renouvelable -s'avère cruciale pour assurer la stabilité du réseau et soutenir la transition vers un mix énergétique plus durable. Les approches classiques (modèles physiques déterministes ou modèles purement data-driven) montrent néanmoins leurs limites : les premières peinent à intégrer la complexité des phénomènes climatiques tropicaux (humidité, cyclones, îlots de chaleur), tandis que les secondes souffrent d'une dépendance importante à de grands volumes de données et présentent des coûts computationnels élevés.Cet article propose une architecture hybride structurant la prévision énergétique en trois couches : (1) un modèle physique fondé sur les bilans énergétiques et les principes thermodynamiques spécifiques aux milieux tropicaux ; (2) une couche statistique (ARIMA, SARIMA, GARCH, SARIMAX) dédiée à la capture des tendances, des effets saisonniers et de la volatilité conditionnelle ; et (3) une couche neuronale (LSTM optimisé) pour modéliser les non-linéarités résiduelles. Des stratégies de compression (pruning, quantification) et d'apprentissage fédéré sont intégrées afin de réduire la consommation énergétique et faciliter le déploiement dans des contextes insulaires contraints.Cette approche hybride améliore la précision des prévisions tout en minimisant l'empreinte computationnelle, contribuant ainsi à une meilleure intégration des énergies renouvelables et à un pilotage résilient des micro-réseaux. Les perspectives incluent une automatisation renforcée du recalibrage, la réduction des pics de charge lors d'événements climatiques extrêmes et l'optimisation à long terme de la planification énergétique pour les territoires tropicaux insulaires.</div
Intense and localized export of selected marine snow types at eddy edges in the South Atlantic Ocean
No full textInternational audienceAbstract. The biological carbon pump (BCP) comprises a wide variety of processes involved in transferring organic carbon from the surface to the deep ocean. This results in long-term carbon sequestration. Without the BCP, atmospheric CO2 concentrations would be around 200 ppm higher. This study reveals that ocean dynamics at the mesoscale and submesoscale could have a major impact on particulate organic matter (POM) vertical distribution. Our results indicate that intense submesoscale frontal regions, such as those between mesoscale eddies, could lead to an important accumulation and transport of POM from the mixed-layer depth (MLD) down to the mesopelagic zone. To reach these conclusions, a multifaceted approach was applied. It included in situ measurements and marine snow images from a BGC-Argo float equipped with an Underwater Vision Profiler (UVP6), satellite altimetry data, and Lagrangian diagnostics. We focused our study on three intense features in marine snow distribution, observed during the 17-month-long float mission in the Cape Basin in the southwest of Africa. These features were located in the frontal region between mesoscale eddies. Our study suggests that a particle injection pump induced by a frontogenesis-driven mechanism has the potential to enhance the effectiveness of the biological pump by increasing the depth at which carbon is injected into the water column. This work also emphasizes the importance of establishing repeated sampling campaigns targeting the interface zones between eddies. This could improve our understanding of the mechanisms involved in the deep accumulation of marine snow observed at eddy interfaces
Century-old herbarium specimen provides insights into Pierce’s disease of grapevines emergence in the Americas
No full textInternational audienceFossils and other preserved specimens are integral for informing timing and evolutionary history in every biological system. By isolating a plant pathogen genome from herbarium-preserved diseased grapevine material from 1906 (Herb_1906), we were able to answer questions about an enigmatic system. The emergence of Pierce’s disease (PD) of grapevine has shaped viticultural production in North America; yet, there are uncertainties about the geographic origin of the pathogen (Xylella fastidiosa subsp. fastidiosa, Xff) and the timing and route of its introduction. We produced a high-quality, de novo genome assembly of this historical plant pathogen and confirmed degradation patterns unique to ancient DNA. Due to the inclusion of the Herb_1906 sample, we were able to generate a significant temporal signal in the genomic data. This allowed us to build a time-calibrated phylogeny, where we estimate the introduction of Xff into the US between 1734 and 1741 CE, an earlier time frame than previously inferred. In a large collection of >300 Xff genomes, the Herb_1906 sample was genetically most similar to a small population from Northern California but not basal to the entire Xff California clade. Based on phylogenetic placement and a phylogeographic reconstruction, our data support a single introduction of Xff into the Southeastern US from Central America, with multiple subsequent introductions into California
Programme MITI-PLUM (Mitigation de la pression lumineuse). Vers l’adaptation en temps réel de l’éclairage public aux enjeux écologiques transitoires du PNR de Brière
No full textNational audienceLa fragmentation des habitats par la lumière artificielle nocturne est une préoccupation centrale parmi les effets de la lumière artificielle sur la biodiversité, créant notamment des modifications dans l’utilisation spatiale des habitats qui peuvent compromettre à terme la réalisation du cycle de vie des espèces — par exemple l’accès aux sites de repos, aux partenaires ou aux sites de reproduction. À l’heure actuelle, les outils dont se dotent les territoires pour juguler les effets écologiques de la pollution lumineuse sont construits sur une connaissance figée de la pression lumineuse et sur des inventaires d’espèces réputées nocturnes, sans considération des temporalités de leur cycle de vie. Pourtant, de nouveaux possibles sont ouverts par l’utilisation de plus en plus massive des luminaires LED en éclairage public : gradation ou extinction, voire adaptation en temps réel — par alertes ou par télégestion – lorsque des conditions météorologiques spécifiques amplifiant la pression lumineuse rencontrent, dans l’espace et dans le temps, des enjeux écologiques transitoires majeurs. Ce sont ces possibles que le programme MITI·PLUM explore dans un territoire de première importance du point de vue écologique : le PNR de Brière. MITI·PLUM s’inscrit donc à la fois dans une perspective de recherche fondamentale et de recherche opérationnelle. Du point de vue fondamental, le programme travaille la caractérisation fine, dans l’espace et dans le temps, des interactions entre lumière artificielle nocturne et paramètres météorologiques afin d’intégrer une approche dynamique, contextualisée et évolutive dans le temps de la pression lumineuse et de pouvoir la mettre en regard d’enjeux liés au cycle de vie d’espèces réputées nocturnes. Sur le plan opérationnel, le programme questionne l’ancrage territorial des réponses imaginées pour traiter la pollution lumineuse en réfléchissant à incorporer les enjeux écologiques transitoires dans les pratiques de gestion de l’éclairage public
A one health approach for integrated vector management monitoring and evaluation
No full textInternational audienceThe French Agency for Food, Environmental and Occupational Health & Safety (Anses) has set up a multidisciplinary working group (WG) to develop an innovative One Health approach for the monitoring and evaluation of an integrated vector management system (IVMS) on a territorial scale. Four existing evaluation guidelines and methods have been combined into a semi-quantitative evaluation approach that takes into account all the dimensions of an integrated process. We propose a set of 34 criteria divided into three sections (obj19ectives and management, implementation, integration) that correspond to the main functional components of an IVMS. Each criterion is assigned a score based on the results of a scoring questionnaire completed by the system's stakeholders, and two graphical outputs are generated using a specific combination of these scores. An overview of the system's performance is provided through a series of pie charts synthesizing the scores for each of the three sections and the corresponding eleven subsections. A radar chart further combines the results according to eight attributes chosen to characterize the qualities of the system. Our approach was tested for the invasive mosquito Aedes albopictus, a main vector of arboviruses, in two French territories with contrasting dengue epidemiology. This approach is intended to be generic and usable in all territories that are at risk of being affected by arboviruses, whether in tropical or temperate regions. Beyond a conventional assessment of the various components of an IVMS, our interdisciplinary and multisectoral approach aims to gain a better understanding of such a system in its environment, its overall functioning and its mechanisms for adapting to contextual change. It also aims to identify avenues for improvement as part of a continuous quality process, and to facilitate comparisons between territories and the cross-fertilization of knowledge between stakeholders
Morphological and biological characteristics of Badamia exclamationis (Fabricius) (Lepidoptera: Hesperiidae) damaging on Hiptage benghalensis (Malpighiaceae) in Viet Nam
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/613562/)International audienceSome morphological and biological characteristics of Badamia exclamationis (Fabricius) were studied on the plant Hiptage benghalensis (L.) Kurz under laboratory and net house conditions at the Department of Plant Protection, College of Agriculture, Can Tho University. Female adults of B. exclamationis began laying eggs 3–4 days after emergence, with an average incubation period of 3.06 days. Larval stage consists of 5 instars with development times of 1.29; 2.00; 1.97; 2.74 and 5.77 days, respectively. The pupal stage lasted for an average of 7.43 days, completing the life cycle in 21–37 days (average 27.46 days). The egg hatching rate was 70%, and the survival rate of the post-egg stages was over 85%. A female laid an average of 104.8 eggs. Damages caused by larvae of B. exclamationis on leaves of H. benghalensis were describeded in details
Motivation toward physical activity and nutrition in older cancer patients: the MONAGE protocol using ecological momentary assessment and accelerometers
No full textInternational audienceBackgroundOlder adults with cancer struggle to maintain recommended levels of physical activity and nutrition during treatments. Collecting data in a real-life context provides a better understanding of the motivational and behavioral dynamics of this population, which is underrepresented in clinical trials. Ecological momentary assessment (EMA) is a frequently used approach to collect repeated measures in real time in a naturalistic environment. This approach can provide insights into the temporal dynamics of psychological processes, such as motivation toward health behaviors. The aim of this study is to identify clusters based on predictive motivational variables related to physical activity and nutritional behaviors among older patients with cancer, via repeated measures.MethodsIn this project, older patients with a cancer (≥ 70 years old) complete physical capacity assessments, malnutrition identification, and a comprehensive geriatric assessment with G-code. After that, participants engage in a 2-week data collection protocol combining EMA and sensor-based monitoring of behavior. The participants wear an ActiGraph GT3X-BT accelerometer (ActiGraph, LLC) on their nondominant waist to measure physical activity. EMA questionnaires are delivered 3 times per day - morning (between 8am and 10am), midday (between 12pm and 2pm) and evening (between 7pm and 8pm) - via smartphones or computers with the UniQ digital application. Motivational constructs based on the Theory of Planned Behavior are collected in the morning and at midday. Nutritional behavior data are collected at midday and in the evening. Fatigue is collected in the morning, at midday and in the evening. The data analysis strategy shall include Multilevel Vector Autoregressive Models with k-means clustering.DiscussionThis project seeks to identify clusters in older patients with cancer based on key motivational predictors related to physical activity and nutritional behaviors, via approaches for collecting repeated measurements in real time within a naturalistic environment. This research into the mechanisms of action between motivation and behaviors could optimize care pathways by designing appropriate intervention content, under conditions where the content will be most effective, to promote sustained behavior change among older adults with cancer.Trial registrationClinicalTrials.gov (NCT06445140). Registered on 06 June 2024
Global Ground-based Tropospheric Ozone Measurements: Reference Data and Individual Site Trends (2000–2022) from the TOAR-II/HEGIFTOM Project
No full textInternational audienceTropospheric ozone trends from models and satellites are found to diverge. Ground-based (GB) observations are used to reference models and satellites but GB data themselves might display station biases and discontinuities. Re-processing with uniform procedures, the TOAR-II Working Group Harmonization and Evaluation of Ground-based Instruments for Free-Tropospheric Ozone Measurements (HEGIFTOM) homogenized public data from 5 networks: ozonesondes, In-service Aircraft for a Global Observing System (IAGOS) profiles, solar absorption Fourier-Transform Infrared (FTIR) spectrometer measurements, Lidar observations, and Dobson Umkehr data. Amounts and uncertainties for total tropospheric ozone (“TrOC”, surface to 300 hPa), free and lower tropospheric ozone, are calculated for each network. We report trends (2000 to 2022) for these segments using Quantile Regression (QR) and Multiple Linear Regression (MLR) for 55 datasets, including 6 multi-instrument stations. The findings: (1) Median TrOC trends computed with QR and MLR trends are essentially the same; (2) Pole-to-pole, across all longitudes, TrOC trends fall within +3 ppbv/decade to -3 ppbv/decade, equivalent to (-4 % to + 8 %)/decade depending on site. (3) The greatest fractional increases occur over most tropical/subtropical sites with decreases at northern high latitudes but these patterns are not uniform. (4) Post-COVID trends are smaller than pre-COVID trends for Northern Hemisphere mid-latitude sites. In summary, this analysis conducted in the frame of TOAR-II/HEGIFTOM shows that high-quality, multi-instrument, harmonized data over a wide range of ground sites provide clear standard references for TOAR-II models and evolving tropospheric ozone satellite products for 2000–2022