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Biopesticide Production from Trichoderma harzianum by Solid-State Fermentation: Impact of Drying Process on Spore Viability
No full textInternational audienceAmong the sustainable agricultural approaches, biological control agents are a promising new alternative to agrochemicals. However, expensive production methods, formulation, poor storage stability and short shelf life are limiting their adoption. One of the promising options for biopesticide production is solid-state fermentation (SSF). This study was conducted to evaluate spore production by two Trichoderma harzianum, Rey 3 and TF2, under forced air drying in SSF. A mixture of agroindustrial byproducts (sugarcane bagasse, vine shoots, wheat bran, potato flour and chitin) were used as substrates. CO 2 generated during fungi growth was recorded by respirometry. We also investigated the effect of hydric stress conditions on the decreasing phase of Trichoderma metabolism as an inducer of sporulation. In parallel, we analyzed the viability of T. harzianum TF2 and spores under different storage conditions (lyophilized, frozen and dried). Under the present culture conditions, the highest production of spores was 10.1 ± 0.3 × 10 9 spores/g DM (Dry Material) at 52 h for T. harzianum Rey 3 and 8.9 ± 0.6 × 10 9 spores/g DM at 72 h for T. harzianum TF2. The forced dry air during the fermentation process had no notable effect on spore production, but it did increase the spore viability (29% viability for T. harzianum Rey 3 and 33% viability for T. harzianum TF2). In parallel, the chitinase, cellulase, xylanase and lipase activities were evaluated, obtaining interesting results regarding enzymatic activities.</div
Iconic gestures on L1 vocabulary acquisition in kindergarteners: A preliminary study
No full textInternational audienceIn typically developing children, language and motor skills are closely interconnected, and gestures may support vocabulary acquisition. Previous research has demonstrated that iconic gestures-those illustrating part of a word's meaning-can enhance learning when observed or imitated. However, most studies have focused on second language (L2) or artificial language learning, with few examining first language (L1) vocabulary acquisition. This preliminary study investigates L1 word learning in French kindergarten children (ages 5-6), focusing on the impact of gestures compared to pictures. Using a within-subject design, 30 children learned 10 new words across two learning conditions: gesture reproduction and picture presentation. The main aim was to assess whether reproducing gestures during learning is more effective than viewing pictures, based on the idea that motor engagement could improve both phonological and semantic memory representations, thereby supporting both fast and slow mapping processes. To evaluate learning outcomes, children completed comprehension (word recognition), production (free recall and naming), and definition tasks to assess the depth of word knowledge. Additional measures included children's initial vocabulary levels and manual dexterity to examine their potential influence on learning performance, particularly in the gesture condition. Findings revealed that the effectiveness of gesture-based learning varied depending on the task. Notably, for the definition task, the benefit of iconic gestures was influenced by the child's initial vocabulary level. These results support the use of pedagogical iconic gestures as an effective teaching tool, while highlighting the importance of considering individual learner characteristics in educational practices.</div
Drivers of plant phenolic concentration across global drylands
No full textInternational audienceAbstract Plant phenolics play a key role in plant defence mechanisms against both biotic and abiotic stressors. However, their responses to environmental variables and grazing pressure across large geographical scales remain poorly understood. Using data from a global survey of 325 plots spanning six continents, we examined how climatic factors, soil properties, leaf nutrients and grazing pressure shape leaf phenolic concentration in 1854 plant species (1280 herbaceous and 574 woody) across global drylands. Our findings reveal that leaf phenolic concentration in herbaceous plants was mainly influenced by grazing pressure and its interactions with leaf nitrogen and iron, which together explained over 50% of observed variation across global drylands. Conversely, phenolic concentration in woody plants was strongly associated with climatic factors, particularly mean annual precipitation (MAP) and mean annual temperature (MAT), which accounted for 80% of the observed variation. While MAP had a positive effect on leaf phenolic concentration in woody plants, grazing pressure buffered this relationship by reducing the influence of MAP. Synthesis. Our study advances the understanding of how biotic and abiotic stressors shape plant defence strategies in global drylands. Our findings shed novel insights about how plant secondary metabolites and their associated functions shift in response to changes in climate and grazing pressure, two key global change drivers with significant implications for ecosystem resilience in drylands worldwide
Growth and phosphorus uptake of micropropagated southern highbush blueberry plants inoculated with ericoid endophytic and mycorrhizal fungi in varied growth substrates
No full textInternational audiencePhosphorus (P) acquisition and use by southern highbush blueberry Vaccinium corymbosum L. plants is critical during early stages of development and impair root development, especially for growth substrates with poor nutrient contents. However, inoculation of blueberry plants with ericoid mycorrhizal fungi (ErMF) or dark septate endophytes (DSE) can improve P during the plants acclimation stages and reduce plant mortality, especially in dry northern Mediterranean climate conditions. Herein, we grew southern highbush blueberry micro-cuttings in conditions without inoculation (control) or in inoculated with four strains: two Ericoid mycorrhizal sp. (D01), and (C01), E. endophyte (C31), and Phialocephala fortinii Wang & Wilcox in sandy (S), fresh field (FF), and FF+S soil mix substrates for 10 months before harvest. At harvest, root colonization levels, plant height, leaf area, the fresh matter of roots and shoots, root-to-shoot ratio, P content, and P utilization efficiency (PUE) were measured. We found that the root colonization levels were inhibited in the S for the different inoculated F treatments, owing to the elevated carbonate and salt concentrations present. The average P uptake responses from the different F inoculated strains were 52.2 %, 29.6 %, and 22.4 % in the S, FF, and FF+S substrates. Inoculation of blueberry plants with C31 strain exhibited the highest (59.1 %) P uptake average response, inoculation with P. fortinii strain showed the lowest (15.8 %) response. The root growth responses were inhibited in the FF+S (-0.2 %), increased in the S (8.4 %), and FF (6.2 %) substrates. Our findings therefore describe responses under controlled nursery conditions with single-strain inoculation and three substrate types. Because blueberry roots in the field are commonly co-colonized by multiple ericoid and endophytic fungi, interactions among partners may amplify or dampen the effects observed here; future work should test coinoculation consortia and validate performance under field conditions.</div
From mapping to action: Social network analysis as a strategic tool in cross-national community interventions
No full textInternational audienceCommunity interventions increasingly leverage Social Network Analysis (SNA) both to understand relational patterns and to facilitate structural changes within networks. Indeed, SNA serves not only as an analytical tool but also as a catalyst for reflection and change. Although SNA has been widely used as an intervention tool, its application in cross-national contexts remains underexplored. This study aims to address this research gap by investigating how SNA can contribute to cross-national community interventions. We use a case study approach based on a longitudinal analysis of the Assistance and Legal Program for Emigrant Support (ALPES) network, a cross-national project established at the Italian-French border. In this project, SNA has been used both as a diagnostic tool to map the information exchange network of third-sector organizations and as a strategic intervention strategy that produced behavioral changes in these organizations. Our results show that SNA functioned as both a translational monitoring tool and a catalytic intervention: network visualization prompted organizations to strategically alter their collaborative patterns and address structural gaps in migrant support services across borders. This demonstrates how network feedback processes can enhance inter-organizational collaboration in complex cross-national contexts
Imperfect condition-based maintenance policy for stochastic degradation systems in dynamic environments
No full textInternational audienc
TRAJECTOIRE 4 A: Adapter - Anticiper - Articuler - Ajuster
No full textTrajectoire 4 A (T4A) is an action research project with two objectives: to help local authorities design their own climate change adaptation trajectory through actions carried out over different timeframes, and to guide them, using innovative reflection/decision-making tools, in reassessing their strategy and readjusting their environmental and territorial planning.T4A is built around geoprospective methods focused on modeling and simulations, with the aim of projecting land-use planning for the study area over the long term and encouraging local stakeholders to explore new ways of adapting to climate change that are suited to the diversity of their geographic context. The territory of the Pays de Grasse urban community (Alpes-Maritimes, France) serves as the testing ground for this approach.T4A offers an operational approach that can be replicated by any local government. The sequence of steps in the process provides a guiding framework for co-developing a climate adaptation policy tailored to the specific community, and for implementing it across the territory over the long term: assessing the expectations of local stakeholders, collectively identifying priority issues, gradually learning through prospective experiments using a serious game and a spatial simulation tool, conducting ex ante impact assessments of adaptation actions, engaging in collective reflection on the adaptation pathway based on the impacts of simulated actions, and making necessary adjustments to environmental and land-use planning.T4A has developed a spatial simulation tool called SIMPROSPECT (SIMulations PROSPEctives Ciblées sur la Transition), designed as a platform for reflection and decision support for local governors and public agents who want to learn how to develop and implement a transition pathway in their municipality. SIMPROSPECT is freely accessible on the project’s website (trajectoire4a.org) and it consists of two applications: SIMPROSPECT 1 is focused on testing policy levers that support sustainable mobility, while SIMPROSPECT 2 aims to reduce territorial vulnerabilities to future climate-related risks by enhancing adaptive capacity. Four risk-related themes are addressed: excess mortality among people over 80 during heatwaves, wildfires, flooding from stormwater runoff and mudslides, and water shortagesTrajectoire 4 A (T4A) est une recherche-action qui a une double finalité : aider une collectivité territoriale à concevoir sa propre trajectoire d’adaptation au changement climatique par des actions menées à différentes temporalités, et la guider, par des outils d’aide à la réflexion/décision novateurs, à réévaluer sa stratégie et à réajuster sa planification environnementale et territoriale.T4A est construit autour de méthodes de géoprospective axées sur la modélisation et les simulations, visant à projeter l’aménagement du territoire d’étude sur le temps long et à susciter chez les acteurs locaux de nouvelles réflexions sur les formes d’adaptation au changement climatique appropriées à la diversité de leur contexte géographique. Le territoire de la Communauté d’Agglomération du Pays de Grasse (Alpes-Maritimes, France) constitue le laboratoire d’expérimentation de cette démarche.T4A propose un mode opératoire reproductible à toute collectivité. Le chaînage des différentes phases de la démarche fournit un fil conducteur qui permet de co-construire une politique d’adaptation spécifique à la collectivité puis de l’opérationnaliser sur son territoire et sur le temps long : diagnostic des attentes des acteurs locaux, définition collective des problématiques prioritaires, apprentissage pas à pas des expérimentations prospectives à l’aide d’un jeu-sérieux et d’un outil de simulations spatiales, mesures ex ante des impacts d’actions d’adaptation, réflexion collective sur la trajectoire d’adaptation qui découle des impacts des actions simulées, réajustements de la planification environnementale et territoriale.T4A a créé un outil de simulation spatiale : SIMPROSPECT (SIMulations PROSPEctives Ciblées sur la Transition), conçu pour être un outil de réflexion et d’aide à la décision dédié aux élus et agents souhaitant apprendre à élaborer une trajectoire de transition et à l’opérationnaliser sur leur commune. SIMPROSPECT est en libre accès sur le site internet du projet (trajectoire4a.org) et il se compose de deux applications : SIMPROSPECT 1 vise à tester des leviers d’actions en faveur de la mobilité durable et SIMPROSPECT 2 a pour objectif de réduire les vulnérabilités du territoire face aux risques futurs liés aux changements climatiques en augmentant sa capacité d’adaptation. Quatre thématiques de risque sont considérées : la surmortalité des personnes de plus de 80 ans liée aux vagues de canicule, les incendies, l’inondation par ruissellement pluvial et les coulées de boue, et la pénurie d’eau
H.E.S.S. detection and multi-wavelength study of the 1 blazar PKS 034627
No full textInternational audiencePKS 0346-27 is a Low Synchrotron Peaked (LSP) blazar at redshift 0.991. The very-high-energy (VHE, E > 100 GeV) spectra of blazars are always affected by absorption by the Extragalactic Background Light (EBL) and subsequently, no blazars have been detected in VHE -rays at redshifts exceeding 1. Extending the redshift range of VHE-detected blazars to will yield insights into the cosmological evolution of both the VHE blazar population and the EBL. This is the goal of a target-of-opportunity (ToO) programme by H.E.S.S. to observe flaring high-redshift () blazars. We report on H.E.S.S. ToO and multi-wavelength observations of the blazar PKS 034627. Along with H.E.S.S., simultaneous data from {\it Fermi}-LAT, {\it Swift} (XRT and UVOT), and ATOM have been analysed and modelled using single-zone leptonic and hadronic models. PKS~0346-27 has been detected by H.E.S.S at a significance of 6.3 during one night, on 3 November 2021, while for other nights before and after this day, upper limits on the VHE flux are determined. No evidence for intra-night -ray variability has been found. A flare in high-energy (HE, ~MeV) -rays detected by {\it Fermi}-LAT preceded the H.E.S.S. detection by 2 days. A fit with a single-zone emission model to the contemporaneous spectral energy distribution during the detection night was possible with a proton-synchrotron-dominated hadronic model, requiring a proton-kinetic-energy-dominated jet power temporarily exceeding the source's Eddington limit, although alternative (e.g. multi-zone) models can not be ruled out. A one-zone leptonic model is, in principle, also able to fit the flare-state SED, however, requiring implausible parameter choices, in particular, extreme Doppler and bulk Lorentz factors of
Quantum mixing on large Schreier graphs
No full textQuantum ergodicity describes the delocalization of most eigenfunctions of Laplace-type operators on graphs or manifolds exhibiting chaotic classical dynamics. Quantum mixing is a stronger notion, additionally controlling correlations between eigenfunctions at different energy levels. In this work, we study families of finite Schreier graphs that converge to an infinite Cayley graph and establish quantum mixing under the assumption that the limiting Cayley graph has absolutely continuous spectrum. The convergence of Schreier graphs is understood in the Benjamini-Schramm sense or in the sense of strong convergence in distribution. Our proofs rely on a new approach to quantum ergodicity, based on trace computations, resolvent approximations and representation theory. We illustrate our assumptions on several examples and provide applications to Schreier graphs associated with free products of groups and right-angled Coxeter groups