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Investigating temporal stereotypy in ascidian embryos development
No full textDevelopmental biology explores the mechanisms of embryo formation and development. Here, we focus on ascidian embryo development, which is highly stereotyped, allowing the identification of homologous cells across embryos and thereby enabling the analysis of embryogenesis at the cellular level. In a population of ascidian embryos, cells may divide in different orders across individuals, yet division rates remain similar overtime, resulting in a conserved total cell count at any given timepoint between different embryos. This raises the question of what conditions are necessary to maintain this conservation. To address this, we simulated the evolution of cell counts in a population of ascidian embryos imaged under the microscope. Our results suggest that the conservation of cell count emerges from a tissue-dependent cell lifetime stereotypy. These results provide new insights into the mechanisms underlying the conservation in cell count during ascidian embryogenesis
Thiamine and folate immunolocalization in germinating lentil seeds: A microstructural investigation
No full textInternational audienceHighlights: • Thiamine and folate act as cofactors in many human and vegetal metabolic pathways. • Germination is an effective process for increasing the thiamine and folate content. • Immunohistochemistry can localize the storage area of thiamine and folate. • Image analysis revealed heterogeneous distribution of vitamers in the pulse. • We obtained both quantitative and qualitative information on the metabolite content.Abstract: Thiamine and folate are vital for both human and plant health, serving as cofactors in various metabolic processes. Thiamine is essential for carbohydrate and amino acid metabolism, while folate is crucial for DNA synthesis and the methyl cycle. Germination has been proven to increase thiamine and folate levels in lentils. While high-performance liquid chromatography (HPLC) is effective for measuring vitamin content, it does not reveal the spatial distribution of these compounds within seeds during germination. To address this, immunohistochemistry (IHC) was used in this study to localize and quantify thiamine and folate in dry, soaked, and germinated lentils. The analysis revealed that these vitamins are distributed unevenly across cotyledons and cells. In dry seeds, thiamine and folate were concentrated around starch granules, but in soaked and germinated seeds, they were dispersed throughout the cytoplasm and near protein bodies. This innovative method provided both quantitative and qualitative insights into how germination affects vitamin distribution, enhancing our understanding of seed metabolism and the behavior of vitamins during food processing
Plant diversity enhances ecosystem resistance to increasing grazing pressure in global drylands
No full textInternational audienceUnderstanding the mechanisms that shape ecosystem resistance to increasing livestock grazing pressure, a major driver of land degradation, is essential for predicting its impacts and informing sustainable land management strategies. This issue is particularly relevant in drylands, which host half of the world’s livestock production and are highly vulnerable to desertification caused by overgrazing. Here we conduct a standardized field survey across 73 dryland sites in 25 countries to simultaneously evaluate how climatic, edaphic, vegetation and grazing-related factors influence ecosystem resistance—defined here as the capacity to maintain vegetation cover under increasing grazing pressure. We found that increasing grazing pressure reduced vegetation cover in 80% of sites, with an average decline of 35%. Plant species richness emerged as the strongest predictor of ecosystem resistance, with higher richness associated with lower vegetation cover loss. Functional trait data indicated that this positive effect was mainly explained by complementarity in trait values among plants, rather than by functional redundancy. Our results indicate that conserving plant diversity is key to strengthening ecosystem resistance and sustaining dryland functioning under intensifying grazing pressur
Saisies pénales spéciales et actifs numériques : une nécessaire adéquation
No full textInternational audienc
Rapport sur les services climatiques réussis dans le monde et leurs critères de succès: Livrable commun au Projet ciblé TRACCS-PC1-DIALOG (D5.3) et au Projet Ciblé TRACCS-PC3-DEMOCLIMA (D1)
No full textLes enjeux socio-économiques liés aux effets du réchauffement climatique sont tels qu’une demande croissante d’informations climatiques adaptées pour la mise en place de stratégies d’atténuation et/ou d’adaptation est clairement exprimée par les secteurs économiques (e.g. agriculture, énergie, tourisme, infrastructures terrestres ou maritimes, etc…) et par les territoires/régions qui mesurent pleinement leursvulnérabilités. En réponse à ces demandes, de nombreux projets de recherche nationaux (e.g., la "Convention relative à l’attribution d’un appui financier au bénéfice des services climatiques", signée entre le Ministère de la Transition Écologique et Solidaire (MTES) et le CNRS en mars 2017, ou le développement du portail DRIAS), européens (e.g., le programme ERA4CS « European Research Area for Climate Services » du JPI Climate, ou encore Copernicus) ou internationaux (e.g., les outils développés par la NASA, le GIEC…) ont permis le financement de « services climatiques ». Plusieurs acteurs opérationnels nationaux et européens développent et mettent à disposition des « services climatiques » via des plateformes souvent libres d’accès et enfin, apparaissent sur le marché des bureaux d’études dont l’activité commerciale vise le développement de « services climatiques » à la carte et adaptés aux demandes des clients.L’offre pour les « services climatiques » est donc aujourd’hui multiforme par l’information fournie (données climatiques « simples », indicateurs, outils d’aide à la décision) et par son mode de développement. Face à cette diversité, les enjeux sont de documenter et comprendre le paysage des services climatiques actuels, de faire ressortir les besoins, et de se munir de moyens pour caractériser la réussite des services climatiques, pour évaluer l'existant et guider le développement de nouveaux projets. Menée conjointement par les projets ciblés DIALOG (PC1) et DEMOCLIMA (PC3) du PEPR TRACCS, cette étude vise quatre objectifs :i) Documenter le paysage actuel des services climatiques (section 2) en France et dans le monde (identifiés par la communauté TRACCS) en les présentant par usages et cibles ;ii) Identifier des besoins non satisfaits vis-à-vis des services climatiques (section 4) ;iii) Identifier un ensemble de critères de réussite d'un service climatique pour les évaluer (section 5) ;iv) Proposer des bonnes pratiques pour atteindre ces critères de réussite (section 6); ces éléments guideront les choix des futurs démonstrateurs qui seront conçus et développés au sein de DEMOCLIMA.Notre travail repose en grande partie sur le recueil de dires d'acteurs des "services climatiques", dans une approche "bottom-up"
À l’école de l’évaluation-exclusion
No full textLe Café pédagogique https://www.cafepedagogique.net/2026/01/12/a-lecole-de-levaluation-exclusion/?utm_campaign=Lexpresso_12-01-2026&utm_medium=email&utm_source=ExpressoL’Ecole transformerait-elle l’évaluation en terrible instrument d’exclusion ? Entrelacs des inégalités sociales et scolaires, baccalauréat déclassé au profit du nébuleux système de sélection Parcoursup, « durcissement » des conditions d’obtention du bac et des modalités du contrôle continu, poids anxiogène d’une évaluation permanente, « harmonisation » qui fait de l’enseignant·e une machine à noter des productions standardisées… Cette tribune se veut un appel : à « (ré)inventer une évaluation au service de tous », à préférer la « démo-cratie éducative » au « management de l’exclusion »
Sweet taste induced by miraculin from Sisrè pulp (Synsepalum dulcificum Schumach. & Thonn.) from Benin as affected by heat treatment
No full textInternational audienceThis work focused on the effect of heating treatments on the sweetening property of miraculin contained in Sisrè, the fruit of Synsepalum dulcificum, from Benin. The aim was to define suitable conditions for stabilizing the fruit pulp, at a lower cost while preserving its functional properties. The fruits, collected in the locality of Sèhouè in the Republic of Benin, were frozen whole, pulped and then stored at -20 • C before processing and analyzing. Heat treatments ranging from 40 to 70 • C were applied to the fresh pulp for 5 min. Sensory tests were performed on the heated pulp samples to test the functionality of miraculin and determine the remanence time of the induced sweet taste after treatment at different temperatures. Reverse-phase and steric-exclusion chromatography, in association with electrophoresis were performed to analyze the miraculin content of the pulps, and the generated data were compared with the sensory results. Sensory analysis showed that the sweetening effect of the native pulp before heat treatment lasted at least >1 h 30 min. A significant loss of functionality after exposure of the pulp to temperature values above 50 • C was observed. The results of analyses also showed that from 50 • C, the miraculin concentration decreased significantly. At temperature values above 50 • C, miraculin completely lost its functionality even if the pulp still contained miraculin, probably in its monomeric form that are not active. The intensity and remanence of the sweetening effect of miraculin depended on its concentration. These results demonstrated that the pulp of Sisrè cannot be stabilized by thermal pasteurization and that drying at low temperatures between 40 and 50 • C could be a good technological option for preserving its functionality
Integrating prior information for improving 3D model-driven GAI estimation with application to wheat crops
No full textInternational audienceGreen Area Index (GAI) is a key crop trait obtained through remote sensing with wide applications in agriculture. Although 3D model-driven approaches to retrieve GAI from multispectral reflectance observations are appealing, they are constrained by limitations in the realism of simulated datasets used for training. This study comprehensively explored how to integrate prior information—such as soil background, leaf optical properties, and canopy structure—into radiative transfer models to improve GAI retrieval. A suite of models (MARMIT-2 for soil reflectance, PROSPECT for leaf optical properties, ADEL-Wheat for canopy structure, and LESS for radiative transfer) was employed to generate five simulation datasets incorporating different combinations of prior information. Support Vector Regression (SVR) models were independently trained on these simulated datasets and validated against an extensive data set made of 310 samples of GAI ground measurements and the corresponding SuperDove satellite data. Our results show that stage-specific GAI retrieval integrating detailed prior information on soil and leaf properties (R2 = 0.93, RMSE = 0.47) notably outperforms standard model inversion approaches (R2 = 0.82, RMSE = 0.73). The improved realism of the training dataset stems from three key strategies was discussed in detail including: (1) employing models that integrates physical and biological knowledge; (2) narrowing the training space; and (3) minimizing distribution shifts. While this study focused on GAI estimation for wheat crops using SuperDove observations, the findings can be extended to other crops, vegetation variables, and satellite systems
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
Comparative Analysis of Irradiation Technologies on High-Density Polyethylene (HDPE) for Biopharmaceutical Applications
No full textInternational audienceThe impacts of e-beam and X-ray irradiation on medical-grade high-density polyethylene (HDPE) are compared with that of gamma irradiation to evaluate their potential effects on pharmaceutical applications. An extensive suite of analytical techniques was employed to evaluate the chemical and physical transformations of irradiated HDPE. Key findings indicated that irradiation did not significantly alter the mechanical properties, as tensile strength and elongation at break remained stable across all irradiation types and doses. Thermal analysis via Differential Scanning Calorimetry (DSC) revealed a slight decrease in melting temperature at higher doses, with an equivalent melting temperature peak observed for all three irradiation technologies. Electron Spin Resonance (ESR) detected alkyl and allyl radicals, which decreased over time, showing no significant differences attributable to irradiation type or dose. Colorimetric analysis indicated yellowing in the samples, linked to specific additives. The quantification of methionine oxidized byproducts by High-Performance Liquid Chromatography (HPLC) demonstrated that the oxidation potential was equivalent for the three irradiation technologies for HDPE. The study concluded that there was a lack of significant impact of irradiation technologies on several physical, chemical and mechanical properties of HDPE