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Similarité perçue et cohérence comportementale entre prévention du gaspillage alimentaire et tri des biodéchets
No full textNational audienceUne enquête réalisée auprès de 800 participants met en évidence une représentation différenciée mais cohérente des pratiques d’anti-gaspillage alimentaire et de tri des déchets alimentaires au niveau des ménages. Si les individus perçoivent un lien entre ces comportements, ils les distinguent néanmoins, ce qui rappelle que prévention et gestion des déchets relèvent de registres séparés, bien qu’articulés. La satisfaction des solutions de tri offerte au ménage, les fréquences des pratiques vertueuses d'achats alimentaires et de consommation des restes sont des prédicteurs significatifs de la fréquence de tri. Ce résultat questionne la pertinence de mener séparément les communications institutionnelles en faveur du tri d’une part, et de la diminution du gaspillage d’autre part (en termes de temporalité et de contenu)
Do sex, age or ecological needs shape an endangered Brown Bear population diet? New insights from faecal metabarcoding
No full textInternational audienceConservation strategies usually focus on megafauna and keystone species to protect habitats. In temperate ecosystems, brown bear appears as one of the potential megafauna keystone species thanks to its omnivorous diet. However, most of the trophic interactions' studies used coproscopic analyses that generally miss highly digested items and rarely investigated the effect of sex, age and individual. In addition, the diet was frequently investigated according to climatic seasons, while Bear Ecological Periods -BEP -(e.g. mating, hyperphagia) really drive individual movement and foraging. In this study, we collected brown bear faeces of different age class and sex across BEP from a critically endangered population. We used metabarcoding and four markers specific to plants, fungi, arthropods and vertebrates to investigate the brown bear diet in the Pyrénées mountains. The diet was mainly composed of plants but also of arthropods, vertebrates and fungi. Pyrenean brown bear consumed significantly fewer arthropods during hyperphagia than other BEP, and exhibited preferences for different plant life forms during mating (diversified herbs), pre-hyperphagia (fleshy-fruits) and hyperphagia (dryfruits). Females consumed plants more often than males, which in turn consumed more wild vertebrates. We highlighted the most diverse level of mycophagy (21 genera) of an omnivore Ursid thanks to metabarcoding. We showed the high variability of this brown bear population diet among BEP and sexes, but not among age-classes. This detailed diet study provides new insights for brown bear conservation, and invites similar approaches on other animals
Nanoscale regulation of ROS signaling at the plasma membrane tunes the plant response to osmotic stress
No full textThe spatiotemporal organization of proteins and lipids within membranes is crucial for ensuring proper cellular signaling. While the segregation of proteins and lipids into membrane nanodomains is well established, it remains unclear whether nanodomains can generate gradients of small diffusible molecules. In plants, reactive oxygen species (ROS), especially hydrogen peroxide (H 2 O 2 ), act as a key signaling molecules in response to environmental stimuli such as osmotic stress. However, how extracellular H 2 O 2 affects intracellular signaling has remained unknown. Here, we show that osmotic stimulation induces the formation of localized, H 2 O 2 -rich nano-environments at the cytoplasmic face of the plasma membrane (PM) in Arabidopsis root cells. Using a PM-tethered H 2 O 2 biosensor, we found that these oxidized nanodomains arise from the clustering of RESPIRATORY BURST OXIDASE HOMOLOGs (RBOHs) and RHO OF PLANTS 6 (ROP6), in coordination with aquaporin-mediated H 2 O 2 transport via the PLASMA MEMBRANE INTRINSIC PROTEIN2;7 (PIP2;7). These local redox hotspots at the PM create a feedforward loop in which H 2 O 2 enhances ROP6 nanoclustering thereby amplifying ROS signaling. Disruption of H 2 O 2 production or transport dampens both ROP6 clustering and anisotropic cell expansion, indicating a crucial role for spatially-confined redox signaling in regulating plant growth under osmotic stress. Our findings propose a model in which ROP6/RBOHD-F/PIP2;7 nanodomains function as discrete redox signaling units, redefining ROS signaling at the PM as a structured, signal-specific, and compartmentalized process
Simulation based-inference of epidemiological and phylodynamic models via Neural Posterior Estimation
No full textMathematical models are essential for understanding and forecasting infectious disease dynamics, yet parameter inference remains challenging when likelihoods are intractable or unknown. Simulation-based inference (SBI) offers a powerful alternative by leveraging model simulations in place of explicit likelihood evaluations. However, traditional SBI approaches such as Approximate Bayesian Computation often rely on ad-hoc summary statistics and suffer from reduced efficiency in high-dimensional settings. Recent advances in SBI address these limitations by employing flexible statistical or machine-learning surrogates to approximate likelihoods or posterior distributions, improving scalability and accuracy. Neural Posterior Estimation (NPE), in particular, employs neural density estimators to learn the posterior directly from simulated data, automatically extracting informative representations without requiring handcrafted statistics. Despite its promise, NPE has seen limited application in infectious disease epidemiology and phylodynamics. In this study, we assess the ability of NPE to infer parameters in mechanistic models of infectious disease dynamics. Using data from the 2014 Ebola virus outbreak in Sierra Leone, we present two case studies reflecting common outbreak-analysis scenarios. First, we fit a compartmental Susceptible-Exposed-Infectious-Recovered transmission model to time series of reported cases and deaths. Second, we fit a Birth & Death phylodynamic model with exposed and infectious hosts to an early Ebola virus phylogeny. In both applications, NPE produces accurate and reliable posterior estimates. We further show that the amortized nature of NPE facilitates model calibration and criticism, enabling rapid assessment of model fit across multiple datasets. Our results highlight the potential of NPE as a flexible, scalable, and statistically principled tool for epidemiological and phylodynamic inference. Finally, we provide detailed online tutorials illustrating the NPE workflow in both applications
Nuclear operations with a high penetration of renewables: the case of France
No full textNuclear and intermittent renewables (wind and solar) are generally regarded as the only scalable technologies producing low-carbon electricity. However, the extent to which these technologies can co-exist in a reliable power system depends on whether nuclear units can adjust their operations to renewable output fluctuations. Using hourly data from the French power system, we find that nuclear units are operated quite flexibly, and that the foregone energy production due to "load following" actions (relative to the counterfactual of operating at full capacity during load following events) is currently limited. However, we find that an additional load following event is associated with a slightly higher likelihood of a unit failure. We also find that unit-level minimum output constraints are binding more frequently as system-wide renewable generation increases, especially so for units most exposed to solar generation. In 2024, hours during which available nuclear flexibility was exhausted are associated with non-positive hourly day-ahead prices
A Modern Guide to the Social and Solidarity Economy
No full textInternational audienceThis Modern Guide presents a comprehensive synthesis of contemporary knowledge on the social and solidarity economy (SSE). It provides an overview of the conceptual, historical, organizational, and developmental dimensions of the SSE, exploring current issues through the lenses of public policy, governance, finance, and legislation
Table Olive Production and Processing
No full textInternational audienceBitter compounds naturally present in olive fruit can be broken down to produce palatable olives known as "table olives." In this article, we first provide background information on global table olive production and then describe the most common methods of processing table olives. Phenolic compounds in the olive lead to bitterness and pungency and are responsible for many of the health benefits of olives and olive oil through their antioxidant properties. High salt used in many processing methods is critical to provide shelf stability, but it can be unhealthy, especially for those individuals with cardiovascular disease. One sustainable and healthy alternative packaging initiative is described. Some olives are naturally debittered by natural microorganisms and can be eaten directly off the tree and provide a second healthy alternative
Comparison of ensemble assimilation methods in a hydrological model dedicated to agricultural best management practices
No full textInternational audienceHydrological models are valuable tools for understanding the movement of water and contaminants in agricultural catchments. They are particularly useful for assessing the impact of landscape organization on pesticide transfers and for developing effective mitigation strategies. However, using these models in an operational context requires reducing uncertainties in their outputs, which can be achieved through data assimilation methods. In this study, we aim to integrate surface moisture images into the PESticide and Hydrology Modelling at the catchment scale (PESHMELBA) water and pesticide transfer model using data assimilation techniques. Twin experiments are conducted on a virtual catchment consisting of vineyard plots and vegetative filter strips. We compare the performance of the ensemble Kalman filter (EnKF), the ensemble smoother with multiple data assimilation (ES-MDA), and the iterative ensemble Kalman smoother (iEnKS) in jointly estimating vertical moisture profiles and van Genuchten soil water retention properties of all soil horizons. Results indicate that the ES-MDA performs the best in estimating surface moisture and saturated water contents, while all methods show similar results for subsurface moisture variables and parameters. Furthermore, we examine the sensitivity of the methods to observation error magnitude, observation frequency, and ensemble size to establish an effective assimilation setup. This study paves the way for future operational applications of data assimilation in PESHMELB
Rhizobial motility preference in root colonization of Medicago truncatula
No full textInternational audienceTunnel-like infection thread (IT) structures support root colonization by symbiotic nitrogen-fixing rhizobia bacteria in most legume species. These tip-grown structures are key to direct rhizobia from root hairs to developing nodules, where they are hosted to fix nitrogen. Rhizobia likely progress inside ITs by combining growth and motility, by modes not yet defined. Here, we tackled this question by combining mathematical modeling, live cell imaging, and bacterial mutant phenotyping in Medicago truncatula . Modeling the motion of fluorescently-labeled Sinorhizobium meliloti inside early root hair IT compartments estimated slow movement (2 to 6 µm/h), compatible with passive rather than active motility. Consistent with this model, flagella-less fliF and fliF-fliRdel S. meliloti mutants were impaired in active swimming motility in vitro, yet could colonize host roots and nodules in planta . In contrast, mutation in the rhizobactin 1021 siderophore rhbE biosynthesis gene affected both surface motility in vitro, and host root and nodule colonisation. This mutation also promoted the formation of branched ITs in root hairs, which ultimately resulted in impaired nodule development and infection. Our findings support the model estimation and suggest that S. meliloti prioritises flagella-independent surface translocation, partially by secreting rhizobactin 1021 surfactants to reach developing nodules in M. truncatula
