HAL-CIRAD
Not a member yet
54841 research outputs found
Sort by
: Programme de Recherche MAPE
No full text« Réduction de la Mortalité Aviaire dans les Parcs Éoliens en exploitation » (MAPE) est un programme de recherche multi-acteurs et collaboratif qui réunit pour la première fois l’ensemble des acteurs concernés par la problématique de la mortalité aviaire dans les parcs éoliens terrestres en France Métropolitaine. Grâce à une démarche innovante, portée par la Maison des Sciences de l’Homme SUD (MSH SUD), le Centre d’Écologie Fonctionnelle et Évolutive (CEFE) et le Centre National de Recherche Scientifique (CNRS), ce projet est co-financé sur 4 ans (2020-2024) par le secteur public (ADEME, DREAL Occitanie, Labex Cemeb, OFB, Région Occitanie) et le secteur privé (Fédérations FEE/SER et 23 opérateurs éoliens).La neutralité de la MSH SUD vis-à-vis de la problématique de la mortalité aviaire et du développement éolien permet d’offrir les conditions favorables à la mise en œuvre d’un processus participatif et de concertation entre les acteurs concernés
Contrastive Pretraining for Visual Concept Explanations of Socioeconomic Outcomes
No full textInternational audiencePredicting socioeconomic indicators from satellite imagery with deep learning has become an increasingly popular research direction. Post-hoc concept-based explanations can be an important step towards broader adoption of these models in policy-making as they enable the interpretation of socioeconomic outcomes based on visual concepts that are intuitive to humans. In this paper, we study the interplay between representation learning using an additional task-specific contrastive loss and post-hoc concept explainability for socioeconomic studies. Our results on two different geographical locations and tasks indicate that the task specific pretraining imposes a continuous ordering of the latent space embeddings according to the socioeconomic out-comes. This improves the model’s interpretability as it enables the latent space of the model to associate urban concepts with continuous intervals of socioeconomic outcomes.Further, we illustrate how analyzing the model’s conceptualsensitivity for the intervals of socioeconomic outcomes canshed light on new insights for urban studies
Broader Application of the Time-SIFT Method: Proof-of-Concept of 3-D-Monitoring Study Cases with Various Spatiotemporal Scales
No full textInternational audienceThis chapter aims to check the potential of the Time-SIFT method on varied test cases with different spatiotemporal scales, from the millimeter/minute to the kilometer/decade. It proposes five test cases to demonstrate the ability of the Time-SIFT method to provide coherent multi-temporal 3-D and/or 2-D datasets with limited or no external registration data. To demonstrate the ability of the Time-SIFT method to produce coherent multi-temporal dataset in various situations, the chapter presents distinct case studies: (i) spatiotemporal scales of the image datasets (ii) relative magnitude and spatial patterns of the expected changes; (iii) different data sources; and (iv) varied target phenomena. The authors expect that the Time-SIFT method will help to unlock the existing multi-temporal stereoscopic image archive for a broad range of change detection studies. Finally, to support access to the Time-SIFT method, the authors have opened it up as a module to the Agisoft Metashape software
Nutritional quality of food imports in Caribbean small islands. Evidence from the French West Indies
No full textInternational audienceThis paper investigates the determinants of the nutritional quality of food imports in the French West Indies (Guadeloupe and Martinique), from 1995 to 2016. We use an original dataset reconciling data at the six-digit level of the Harmonized System with data from the French food composition table (Ciqual, 2017). We estimate the impact of several socioeconomic factors and food processing on per-capita imports of key markers of the nutrition transition: kilocalories, animal protein, saturated fat, and sugar. Results suggest that an increase in the per-capita GDP in the French West Indies increases per-capita imports in terms of kilocalories and saturated fat. Retail expansion is shown to contribute to the nutrition transition via increasing per-capita imports of our nutrition outcomes (except for sugar). We also show that processed and ultra-processed foods are associated with higher per-capita imports of our nutrition outcomes. Finally, the impact of the female labor force participation rate is found to be statistically insignificant
Global patterns of tree wood density
No full textInternational audienceWood density is a fundamental property related to tree biomechanics and hydraulic function while playing a crucial role in assessing vegetation carbon stocks by linking volumetric retrieval and a mass estimate. This study provides a high‐resolution map of the global distribution of tree wood density at the 0.01° (~1 km) spatial resolution, derived from four decision trees machine learning models using a global database of 28,822 tree‐level wood density measurements. An ensemble of four top‐performing models combined with eight cross‐validation strategies shows great consistency, providing wood density patterns with pronounced spatial heterogeneity. The global pattern shows lower wood density values in northern and northwestern Europe, Canadian forest regions and slightly higher values in Siberia forests, western United States, and southern China. In contrast, tropical regions, especially wet tropical areas, exhibit high wood density. Climatic predictors explain 49%–63% of spatial variations, followed by vegetation characteristics (25%–31%) and edaphic properties (11%–16%). Notably, leaf type (evergreen vs. deciduous) and leaf habit type (broadleaved vs. needleleaved) are the most dominant individual features among all selected predictive covariates. Wood density tends to be higher for angiosperm broadleaf trees compared to gymnosperm needleleaf trees, particularly for evergreen species. The distributions of wood density categorized by leaf types and leaf habit types have good agreement with the features observed in wood density measurements. This global map quantifying wood density distribution can help improve accurate predictions of forest carbon stocks, providing deeper insights into ecosystem functioning and carbon cycling such as forest vulnerability to hydraulic and thermal stresses in the context of future climate change
On some mathematical issues about the Sterile Insect Technique against fruit fly
No full textInternational audienceThe Sterile Insect Technique (SIT) is an autocidal method to control vector of diseases and crop pest, like fruit flies. It consists of releasing males sterilized by ionization, in a targeted area, that will mate with the wild females, resulting in a reduce, eventually a local elimination, of the wild population. While conceptually very simple, SIT is challenging to set-up, at an industrial scale.In this talk, I focus on the impact of residual fertility [1] and double-mating on the SIT efficacy against fruit fly [2]. There is a balance to find between competition, sterilization level and residual fertility. The lower the irradiation the higher the residual fertility. In addition, multiple mating enhances the fitness of wild fruit fly. In this talk, we consider single and double-mated females. Thus, in our model, we distinguish females mated with fertile(sterile) and then sterile(fertile) males, and also females mated once or twice with wild males only.We derive an upper bound for the residual fertility related to the parameters of single- and double- mated females. We show that when the residual fertility is small enough, there exists a release threshold above which local elimination is possible.We illustrate our results with several simulations and show that, in some cases, re-mating may be beneficial for SIT [2]. We discuss the results in terms of real application within the framework of the project AttracTIS (funded by Ecophyto II) against the oriental fruit fly in La Réunion
Early transcriptomic responses of rice leaves to herbivory by Spodoptera frugiperda
No full textInternational audienceDuring herbivory, chewing insects deposit complex oral secretions (OS) onto the plant wound.Understanding how plants respond to the different cues of herbivory remains an active areaof research. In this study, we used an herbivory-mimick experiment to investigate the earlytranscriptional response of rice plants leaves to wounding, OS, and OS microbiota from Spodopterafrugiperda larvae. Wounding induced a massive early response associated to hormones such asjasmonates. This response switched drastically upon OS treatment indicating the activation of OSspecific pathways. When comparing native and dysbiotic OS treatments, we observed few generegulation. This suggests that in addition to wounding the early response in rice is mainly driven bythe insect compounds of the OS rather than microbial. However, microbiota affected genes encodingkey phytohormone synthesis enzymes, suggesting an additional modulation of plant response by OSmicrobiota
Battery Electricity Storage Systems, the energy sector's next big tech
No full text: Vietnam's rapid expansion in renewable energy, particularly solar and wind,necessitates the adoption of Battery Electricity Storage Systems (BESS) to address theintermittency of these sources and ensure grid reliability. This article provides anoverview of BESS fundamentals, including their operational principles, economicimplications, and potential benefits for Vietnam. Despite the current lack of large-scale BESS deployment in Vietnam, the global market is growing rapidly, driven bytechnological advancements and decreasing costs. The article examines the presentstate of BESS in Vietnam, highlighting local manufacturing capabilities and regulatorychallenges. It also explores strategic approaches outlined in Vietnam's National PowerDevelopment Plan (PDP 8) and long-term projections for BESS integration. WhileBESS has the potential to significantly enhance Vietnam's energy landscape, itssuccessful implementation will depend on addressing economic, regulatory, andtechnical challenges
Value chains middlemen's roles in the market gardeners' crop planning: which impact on farmers adaptive capacity?
No full textInternational audienceVegetable producers have to deal with product perishability, systems complexity, and to match farmers’ constraints and objectives with value chain expectations. In this context, we aimed to understand to what extent farmers adapt their crop planning to face increasing disturbances. We conducted a diagnosis of crop planning using a method inspired by diagnosis of uses with vegetable producers selling to middlemen in long value chains in the Roussillon plain, Southern France. Our analysis shows that farmers’ constraints and objectives combined with middlemen expectations result in partial adaptive capacity for farmers to choose crops to grow, dates to choose and volumes to reach. Two different strategies can provide farmers adaptive capacity: diversify or specialize, these strategies being applied to the number of crops grown or the number of outlets. Our results also show that adaptation requires various adaptive capacities depending on the disturbance faced. Our results, analysing farmers individual adaptive capacity, call for a broadening of focus to consider collective adaptive capacities involving middlemen and other farmers of supply basin
