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Innover dans la prise en charge des maladies chroniques dans un pays du Sud :coordination des soins, interprofessionnalité, formation et appui du numérique pouraméliorer les parcours de soins
No full textInternational audienc
Aquatic ecosystem indices, linking ecosystem health to human health risks
No full textInternational audienceThe good functioning of aquatic ecosystems is essential for providing diverse ecosystem services that benefit humans. The degradation of ecosystem health due to continuous stressors, such as climate change or water pollution, is leading to an increase in human health risks and well-being. Indicators have been developed to determine human health risks from recreational and drinking water. Still, a general application to aquatic ecosystems linking ecosystem health and human health risks has not been done. We here reviewed indicators and indices applied to assess the health of aquatic ecosystems and their links with human health risk and well-being. We evaluated the extent to which indicators can witness a risk to human health and well-being. A total of 245 articles were reviewed, consisting of 185 on the assessment of aquatic ecosystem health and 60 linking ecosystem health and human health or well-being. Out of the 65 indices described, we evaluated the use of several parameters and their relevance to evaluate human health risks, including physico-chemical parameters, bioindicators, contaminants, and pathogens, therefore covering the various sources of ecosystem disturbance. Based on our assessment, we propose a set of indicators that would allow for the inclusion of risks for human health and well-being in the assessment of ecosystem health (e.g. coliforms, algae, pH, nutrients, chemical compounds, and ecosystem services). Measuring these parameters should be incorporated into future studies to allow an understanding of the linkage of ecosystem and human health
Sources of variation in plant chemical diversity: Lessons from Malagasy <i>Ficus</i>
No full textDATA AVAILABILITY STATEMENT: All code and data needed to replicate these analyses and results are archived on Zenodo (https://doi.org/10.5281/zenodo.15108673). Sequencing data are available in GenBank (see more information in Appendix S1).International audiencePremise: Plants produce a tremendous variety of secondary compounds that are crucial to interspecific and intraspecific interactions and for adaptation to environmental changes. This chemical diversity has been attributed to multiple factors, including interactions with herbivores or pollinators, tissue‐specific needs, and evolutionary constraints. The interplay between a vast array of factors driving plantchemodiversity remains unclear, mainly because most studies have focused on a single organ—mostly leaves—or, when comparing different organs, have been limited to single taxa. Thus, the relationship between functional and phylogenetic factors remains unresolved. We use a model system of Ficus from Madagascar to examine the extent to which phytochemical diversity is shaped by tissue‐specific function and the degree to which phylogenetic relatedness explains variation in fruit and leaf chemodiversity.Methods: We applied an untargeted metabolomics approach to unripe fruits (the syconium, a hollow structure containing numerous small flowers) and leaves from eight species of wild figs (Ficus spp.) sampled in a tropical rainforest in Madagascar. We characterized their chemical profiles using ultra‐performance liquid chromatography–mass spectrometry and reconstructed their phylogeny using six genetic markers to understand the patterns of chemodiversity.Results: Fruit and leaf metabolomes were more similar to the same organ in other species than to the other organs within the same species. There was a significant but moderate phylogenetic correlation in fruit and leaf chemodiversity.Conclusions: Although phylogenetic relatedness influences plant chemodiversity in Malagasy figs, functional convergence of tissue‐specific metabolites may be a major evolutionary driver
Grazing Modulates the Multiscale Spatial Structure of Dryland Vegetation
No full textInternational audiencePlants can facilitate their local environment and create a two‐phase spatial structure of vegetation and bare soil in drylands, which largely influences ecosystem functioning. Although an increasing number of studies have examined how global change drivers like aridity influence vegetation spatial structure in drylands (e.g., the patch size distribution), it remains unclear how grazing impacts differ from those of climatic gradients, how these effects vary with herbivore feeding habits, and which plant‐level traits—such as size and life form—mediate these spatial responses. Here, we coupled spatial vegetation pattern analyses of ecosystem images with field data analyses of the size distribution and dominant life forms of plants from 326 plots sampled across 25 countries and six continents to explore the effects of herbivores on the spatial structure of dryland vegetation. The effects of herbivores on vegetation spatial structure were opposite to the effects of aridity. Specifically, vegetation in grazed areas was clustered into larger patches, with fewer small patches, which skewed the patch‐size distribution towards larger patches. These effects differed between browsing and grazing herbivores. Grazing effects were partially explained by the fact that grazing reduced average plant size, increased shrub density, and promoted facilitation among species of contrasting sizes. Similar effects were also confirmed by using model simulations that accounted for positive plant interactions. By linking remotely sensed images, a global field survey, and a mathematical model, our study uncovers the species‐level mechanisms by which herbivores shape ecosystem‐level spatial patterns and provides insights into the consequence of herbivory pressure on the resilience of drylands
A combined territorial life cycle assessment and ecosystem services valuation to analyse the environmental performance of coastal planning scenarios: Insights from a case study in southern France
No full textInternational audienceA territory, which is a geographical area qualified by a legal affiliation or by a natural or cultural feature, presents an appropriate scale for establishing responsibilities and initiating sustainable development actions. At the same time, globalization implies constant interaction of territories with the rest of the world. The management of territorial projects therefore requires a revised set of environmental assessment tools that consider local and global issues with a multi-scale perspective. The environmental benefits of land use policies can, however, remain hidden behind global approaches such as life cycle assessment (LCA), which are generally productoriented and tend to ignore ecosystem services (ES). This paper aims to propose new decisionmaking tools for land use planning based on the joint use of ecosystem services assessment (ESA) and territorial Life Cycle Assessment (T-LCA). Within the T-LCA framework, two main types of indicators were quantified. On the one hand, the services provided by land planning scenarios were computed by the ESA by considering provisioning, cultural and regulation ES. On the other hand, environmental impacts were characterized using the Impact World+ Life Cycle Impacts Assessment (LCIA) method. Two contrasting scenarios and a business as usual scenario (BAU) were studied and compared as a proof of concept. Scenario 1 focused on productive economy by maintaining and diversifying the shellfish farming sector, which is a strong component of the area's social identity. Scenario 2 favoured the development of tourism. Overall, the results indicated that environmental damages varied only slightly between scenarios, with tourism activities (i.e., transport and accommodation) emerging as the primary contributors. In contrast, there were very different profiles in terms of socio-economic benefits depending on the scenario. Provisioning ES were very high in scenario 1, while scenario 2 led to a clear increase in cultural ES. This research emphasizes the importance of developing integrated assessment approaches when creating local planning policies, in order to identify potential trade-offs between environmental impacts and benefits, and local and global issues
Redox behavior of ruthenium in borosilicate glass melts for nuclear waste vitrification
No full textInternational audienceMost of radionuclides are soluble in high-level waste borosilicate glass and are integrated in the vitreous network.However, Ruthenium and Palladium are poorly soluble and form RuO particles and Pd-Te beads (Fig. 1a) during thevitrification process. Ruthenium is highly conductive and forms needle-shaped particles that may change the physicalproperties of the glass melt. Moreover, particles containing Ru0 are sometimes observed in nuclear glasses (Fig. 1b).These particles are then bigger and denser, and Ru is more conductive than RuO. Therefore, the unexpected reduction of RuO in Ru may have a significant impact on the physical properties of the melt and hinder the vitrification process.pour la présentation de mes résultats de thèse, publiée en 2021:Etude de la réduction de RuO2 en Ru0 dans une fonte verrière borosilicatée simplifiée à p(O2) et T connues. Très bon accord entre les expériences et les résultats des calculs CALPHAD menés avec la base de données thermodynamique. En complexifiant le système avec Pd et Te, les résultats divergent
Scaling up ocean conservation through recognition of key biodiversity areas in the Southern Ocean from multispecies tracking data
No full textInternational audienceBiodiversity is critical for maintaining ecosystem function but is threatened by increasing anthropogenic pressures. In the Southern Ocean, a highly biologically productive region containing many endemic species, proactive management is urgently needed to mitigate increasing pressures from fishing, climate change, and tourism. Site‐based conservation is one important tool for managing the negative impacts of human activities on ecosystems. The Key Biodiversity Area (KBA) Standard is a standardized framework used to define sites vital for the persistence of global biodiversity based on criteria and quantitative thresholds. We used tracking data from 14 species of Antarctic and subantarctic seabirds and pinnipeds from the publicly available Retrospective Analysis of Antarctic Tracking Data (RAATD) data set to define KBAs for a diverse suite of marine predators. We used track2kba, an R package that supports identification of KBAs from telemetry data through identification of highly used habitat areas and estimates of local abundance within sites. We compared abundance estimates at each site with thresholds for KBA criteria A1, B1, and D1 (related to globally threatened species, individual geographically restricted species, and demographic aggregations, respectively). We identified 30 potential KBAs for 13 species distributed throughout the Southern Ocean that were vital for each individual species, population, and life‐history stage for which they were determined. These areas were identified as highly used by these populations based on observational data and complement the ongoing habitat modeling and bioregionalization work that has been used to prioritize conservation areas in this region. Although further work is needed to identify potential KBAs based on additional current and future data sets, we highlight the benefits of utilizing KBAs as part of a holistic approach to marine conservation, given their significant value as a global conservation tool.Ampliación de la conservación oceánica por medio del reconocimiento de áreas importantes de biodiversidad en el Océano Antártico a partir de datos de rastreo de varias especies Resumen La biodiversidad es fundamental para mantener la función de los ecosistemas, pero está amenazada por las crecientes presiones antropogénicas. En el Océano Antártico, una región con mucha producción biológica que contiene numerosas especies endémicas, se necesita urgentemente una gestión proactiva para mitigar las crecientes presiones de la pesca, el cambio climático y el turismo. La conservación basada en el sitio es una herramienta importante para gestionar los efectos negativos de las actividades humanas en los ecosistemas. El Estándar de Áreas Clave para la Biodiversidad (ACB) es un marco estandarizado que se utiliza para definir lugares vitales para la persistencia de la biodiversidad mundial con base en criterios y umbrales cuantitativos. Usamos datos del seguimiento de 14 especies de aves marinas y pinnípedos antárticos y sub‐antárticos del conjunto de datos públicos Retrospective Analysis of Antarctic Tracking Data (RAATD) para definir las ACB de un conjunto diverso de depredadores marinos. Utilizamos track2kba, un paquete de R que permite la identificación de ACB a partir de datos telemétricos mediante la identificación de áreas de hábitat altamente utilizadas y estimaciones de abundancia local dentro de los sitios. Comparamos las estimaciones de abundancia en cada lugar con los umbrales de los criterios A1, B1 y D1 de las ACB (relacionados con especies amenazadas a nivel mundial, especies individuales restringidas geográficamente y agregaciones demográficas, respectivamente). Identificamos 30 ACB potenciales para 13 especies distribuidas por todo el Océano Antártico que eran vitales para cada especie individual, población y etapa del ciclo biológico para las que se determinaron. Estas áreas fueron identificadas como muy utilizadas por estas poblaciones con base a datos observacionales y complementan el trabajo en curso de modelos del hábitat y biorregionalización que se ha utilizado para priorizar las áreas de conservación en esta región. Aunque es necesario seguir trabajando para identificar posibles ACB basadas en conjuntos de datos adicionales actuales y futuros, destacamos los beneficios de utilizar las ACB como parte de un enfoque holístico de la conservación marina, dado su importante valor como herramienta de conservación global
Simulating the efficacy of wolf-dog hybridization management with individual‐based modeling
No full textInternational audienceIntrogressive hybridization between wolves and dogs is a conservation concern due to its potentially deleterious long‐term evolutionary consequences. European legislation requires that wolf–dog hybridization be mitigated through effective management. We developed an individual‐based model (IBM) to simulate the life cycle of gray wolves that incorporates aspects of wolf sociality that affect hybridization rates (e.g., the dissolution of packs after the death of one/both breeders) with the goal of informing decision‐making on management of wolf–dog hybridization. We applied our model by projecting hybridization dynamics in a local wolf population under different mate choice and immigration scenarios and contrasted results of removal of admixed individuals with their sterilization and release. In several scenarios, lack of management led to complete admixture, whereas reactive management interventions effectively reduced admixture in wolf populations. Management effectiveness, however, strongly depended on mate choice and number and admixture level of individuals immigrating into the wolf population. The inclusion of anthropogenic mortality affecting parental and admixed individuals (e.g., poaching) increased the probability of pack dissolution and thus increased the probability of interbreeding with dogs or admixed individuals and boosted hybridization and introgression rates in all simulation scenarios. Recognizing the necessity of additional model refinements (appropriate parameterization, thorough sensitivity analyses, and robust model validation) to generate management recommendations applicable in real‐world scenarios, we maintain confidence in our model's potential as a valuable conservation tool that can be applied to diverse situations and species facing similar threats.Simulación de la eficiencia de la gestión de híbridos de perro y lobo con modelos basados en individuos Resumen La hibridación introgresiva entre perros y lobos es un tema de conservación por las posibles consecuencias evolutivas deletéreas a largo plazo. Las leyes europeas requieren que estos híbridos se mitiguen mediante una gestión efectiva. Desarrollamos un modelo basado en individuos (MBI) para simular el ciclo de vida del lobo gris que además incorpora los aspectos sociales de los lobos que afectan las tasas de hibridación (p. ej.: la disolución de las manadas después de la muerte de uno o ambos reproductores) con el objetivo de guiar las decisiones de gestión de estos híbridos. Aplicamos nuestro modelo con la proyección de las dinámicas de hibridación en una población local de lobos bajo diferentes selecciones de pareja y escenarios de inmigración y contrastamos los resultados de la extirpación de individuos mezclados con su esterilización y liberación. En varios escenarios, la falta de gestión llevó a una mezcla completa, mientras que las intervenciones de gestión reactiva redujeron de forma efectiva la mezcla en las poblaciones de lobos. Sin embargo, la eficiencia de la gestión dependió en su mayoría de la selección de pareja y el número y nivel de mezcla de los individuos inmigrantes a la población de lobos. La inclusión de la mortalidad antropogénica que afecta a los individuos parentales y mezclados (p. ej.: la cacería) incrementó la probabilidad de que se disolviera la manada y por lo tanto incrementara la probabilidad del entrecruzamiento con perros o individuos mezclados, además de que aumentó la hibridación y las tasas de introgresión en todos los escenarios de simulación. Reconocemos la necesidad de refinar el modelo (parametrización adecuada, análisis detallados de sensibilidad y validación del modelo robusto) para generar recomendaciones de gestión aplicables en escenarios reales y mantenemos la confianza en el potencial de nuestro modelo como una herramienta valiosa de conservación que podría aplicarse a diferentes situaciones y especies que enfrentan amenazas similares
Neural prediction of Lagrangian drift trajectories on the sea surface
No full textInternational audienceWe simulate Lagrangian drift on the sea surface and investigate deep learning approaches to address the shortcomings of current model-based and Markovian approaches, particularly concerning error propagation and computational complexity. We present a novel deep learning framework, referred to as DriftNet, inspired by the Eulerian Fokker-Planck representation of Lagrangian dynamics. Through numerical experiments for simulated and real drift trajectories on the sea surface, we illustrate the effectiveness of DriftNet compared to existing state-of-the-art schemes. We also delve into the influence of diverse geophysical fields, whether derived from models or observations, used as inputs by DriftNet on drift simulation. Our objective is to assess the amount of dynamic information required to accurately simulate realistic trajectories
Proper account of auto-correlations improves decoding performances of state-space (semi) Markov models
No full textInternational audienceState-space models are widely used in ecology to infer hidden behaviors. This study develops an extensive numerical simulation-estimation experiment to evaluate the state decoding accuracy of four simple state-space models. These models are obtained by combining different Markovian specifications (Markov and semi-Markov) for the hidden layer with the absence (model AR0) and presence (AR1) of auto-correlation for the observation layer. Model parameters are issued from two sets of real annotated trajectories. Three metrics are developed to help interpret model performance. The first is the Hellinger distance between Markov and semi-Markov sojourn time probability distributions. The second is sensitive to the overlap between the probability density functions of state-dependent variables (e.g., speed variables). The third quantifies the deterioration of the inference conditions between AR0 and AR1 formulations. It emerges that the most sensitive model choice concerns the auto-correlation of the random processes describing the state-dependent variables. Opting for the absence of auto-correlation in the model while the state-dependent variables are actually auto-correlated, is detrimental to state decoding performance. Regarding the hidden layer, imposing a Markov structure while the state process is semi-Markov (with negative Binomial sojourn times) does not impair the state decoding performances. The real-life estimates are consistent with our experimental finding that performance deteriorates when there are significant temporal correlations that are not accounted for in the model. In light of these findings, we recommend that researchers carefully consider the structure of the statistical model they suggest and confirm its alignment with the process being modeled, especiallywhen considering the auto-correlation of observed variables