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À la juste taille de la machine. La taille des troupeaux sous l’effet de seuil d’une traite robotisée
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Wood heating and moral licensing: a survey study
No full textInternational audienceA rebound effect occurs when an energy efficiency improvement results in less energy savings than expected. Usually, this phenomenon is attributed to a price effect, as improvements in the energy efficiency of a technology reduce its cost of use, thereby encouraging increased usage. Recent studies taking into account environmental preferences suggest that the rebound effect is not only due to a price effect. A behavioral phenomenon, called moral licensing effect, may also lead users of a more efficient technology (often less damaging to the environment) to feel less guilt to use it more, and thus to increase the rebound effect. We conducted a survey involving 1,510 French households to explore the moral licensing effect in the context of heating behavior. First, we show that most people declare they would increase their heating consumption if it had a lesser environmental impact. Second, we show that wood heating is perceived as a heating fuel with less environmental impact than oil, gas and electricity. Based on these results we conclude that policies promoting wood heating as a more environmentally friendly energy source may indeed induce a moral licensing effect, leading people to increase their heating usage and potentially counteracting expected environmental benefits of wood heating
Highly efficient hydrosilylation of alkenes using a recyclable ZnO nanoparticle catalyst under ligand-free conditions
No full textInternational audienceFaced with economic and environmental challenges, there is a growing demand for durable and efficient catalysts based on non-precious transition metals, which offer both high activity and excellent recyclability. This study focuses on the synthesis of zinc oxide (ZnO) nanoparticles via a hydrothermal method and their characterization using X-ray diffraction and scanning electron microscopy. Furthermore, the study investigates the optimization of reaction conditions and the application of these ligand-free nanocatalysts in the hydrosilylation of alkenes with various hydrosilanes. The silylated products were characterized by 1H, 13C, and 29Si NMR spectroscopy, confirming the successful and efficient conversion of alkenes. The results demonstrate that the catalysts exhibit stable performance even after multiple recycling cycles
Structural variations, gene polymorphism and expression reveal major candidate genes associated with pod and seed size variation during peanut (Arachis hypogaea L.) domestication
No full textData availability: The raw RNA-Seq data generated and analyzed in the current study are publicly available in the ArrayExpress collection in BioStudies under the accession number: E-MTAB-15520 (https:/www.ebi.ac.uk/biostudies/arrayexpress/studies/E-MTAB-15520).Tribute: The authors would like to pay tribute to their colleague, Professor Djibril Sane, who passed away in September 2020. He was involved in the supervision of Mounirou H. Alyr.International audienceBackground: Pod size is a key agronomic trait in peanut (Arachis hypogaea) that underwent strong selection during domestication. In a previous study, we fine-mapped a quantitative trait locus (QTL) for pod and seed size to a 168.37 kb region on chromosome A07. Here, we integrated structural variation analysis, gene sequence comparison, and transcriptomic profiling to refine candidate genes and uncover molecular mechanisms underlying domestication-related differences in pod size.Results: Comparative genomic analyses among Arachis duranensis, A. monticola, and four cultivated varieties (Fleur11, Tifrunner, Shitouqi, Fuhuasheng) revealed multiple structural variations in the QTL interval, including a ~ 25 kb inversion between the wild species (A. duranensis and A. monticola) and all cultivated genotypes. This inversion altered the orientation of a candidate gene, Aradu.DN3DB/Arahy.5EZV1I (SAP), which also carried a non-synonymous SNP distinguishing wild and cultivated lines. RNA-Seq profiling of two parental lines (Fleur11 and 12CS_091) and two near-isogenic lines (NILs) at 20 and 40 days after flowering (DAF20, DAF40) identified two differentially expressed genes in the QTL region: Aradu.SFU0J/Arahy.VEUG4Z (phytochromobilin synthase) and gene.15763 (mitochondrial ribosomal protein), both showing higher expression in large-pod genotypes. GO enrichment analysis revealed contrasting strategies between pod size groups: small-pod genotypes emphasized early maturation and storage metabolism, while large-pod genotypes maintained prolonged growth through hormonal signaling and cell division, supporting greater pod expansion.Conclusions :This study identifies three promising candidate genes for seed and pod size variation during peanut domestication: Aradu.DN3DB/Arahy.5EZV1I, gene.15763, and Aradu.SFU0J/Arahy.VEUG4Z. The ~25 kb inversion affecting Aradu.DN3DB/Arahy.5EZV1I and the expression differences in Aradu.SFU0J/Arahy.VEUG4Z between large- and small-pod genotypes suggest structural and transcriptional mechanisms contribute to phenotypic variation. These findings advance understanding of domestication-related traits in peanut and provide a foundation for functional validation, which could guide breeding strategies to optimize pod and seed size
Phase Transition for Stochastic Block Model with more than Communities
No full textPredictions from statistical physics postulate that recovery of the communities in Stochastic Block Model (SBM) is possible in polynomial time above and only above the Kesten-Stigum (KS) threshold. This conjecture has given rise to a rich literature, proving that non-trivial community recovery is indeed possible in SBM above the KS threshold, as long as the number K of communities remains smaller than √ n, where n is the number of nodes in the observed graph. Failure of low-degree polynomials below the KS threshold was also proven when Chin et al. [Chi+25] recently prove that, in a sparse regime, community recovery in polynomial time is possible below the KS threshold by counting non-backtracking paths. This breakthrough result lead them to postulate a new threshold for the many communities regime K ≥ √ n. In this work, we provide evidences that confirm their conjecture for K ≥ √ n: 1-We prove that, for any density of the graph, low-degree polynomials fail to recover communities below the threshold postulated by Chin et al. [Chi+25] ; 2-We prove that community recovery is possible in polynomial time above the postulated threshold, not only in the sparse regime of [Chi+25], but also in some (but not all) moderately sparse regimes, essentially by counting occurrences of cliques or self-avoiding paths of suitable size in the observed graph.In addition, we propose a detailed conjecture regarding the structure of motifs that are optimal in sparsity regimes not covered by cliques or self-avoiding paths counting. In particular, counting self-avoiding paths of length --which is closely related to spectral algorithms based on the Non-Backtracking operator--is optimal only in the sparse regime. Other motif counts--unrelated to spectral properties--should be considered in denser regimes
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)
Exploring eight-year trajectories of diet-related environmental pressures in the NutriNet-Santé cohort
No full textInternational audienceAbstract Few studies have explored individual diet-related environmental pressure changes, beyond greenhouse gas emissions (GHGe) and land occupation (LO). This study evaluates the trajectories in several environmental impacts of diets among 8,905 French adults from the NutriNet-Santé cohort, who completed food frequency questionnaires (distinguishing organic vs. conventional foods) in 2014, 2018, and 2022. Six environmental indicators—GHGe, LO, energy demand, ecological infrastructure use, water use, and pesticide use—were estimated at the farm perimeter using a multi-source approach. Latent class models identified trajectories for a composite environmental pressure index (EPI) and each indicator, and mixed models adjusted for energy intake and sex modeled the trajectories. On average, most environmental pressures decreased over time (e.g., GHGe by -12%, water use by -1%), indicating a general improvement. However, ecological infrastructure also declined (-9%), which represents a negative outcome as it is linked to biodiversity. Two to four trajectory profiles were identified per indicator, with most individuals showing stable or modestly decreasing trends. Four EPI trajectories emerged: increasing EPI profiles were associated with higher meat consumption, whereas decreasing EPI reflected shifts toward more plant-based diets. Despite potential awareness of the importance of sustainable diets, this study reveals that most individuals show moderate improvements in their diet-related environmental pressures, with only a very small fraction showing important decreases
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
Quantifying the impact of co-registration and satellite jitter filtering on the accuracy of multi-temporal elevation differences
No full textInternational audienceMulti-temporal satellite-based change detection analysis requires addressing biases related to coregistration and satellite jitter. This study compares two workflows combining two co-registration strategies with jitter filtering using Pléiades imagery from 2015 and 2023. The Time-SIFT approach shows improved horizontal accuracy and comparable vertical accuracy compared to the classical approach without requiring GCPs or pre-georeferenced data, reducing elevation difference dispersion from 1.71 to 1.32 m in terms of NMAD. After jitter correction, dispersions reach 1.13 m and 0.96 m NMAD for the classical and the Time-SIFT approaches, respectively. These results demonstrate that the Time-SIFT co-registration quality yields improved elevation difference after filtering