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Modélisations multi-niveaux des inégalités sociales et spatiales de la qualité de l’alimentation. Exploration du rôle de l’environnement alimentaire
No full textInternational audienceNous explorons l’effet du support spatial 1/ sur la mesure et caractérisation des environnements alimentaires en France, et 2/ sur la qualité de l’alimentation, en considérant les problématiques d’accès socio-économiques (effets du statut socioéconomique) et spatiaux (en fonction du lieu décrit à l’échelle du quartier, et du milieu de résidence : urbain versus rural). Nous proposons deux modélisations multi-niveaux et nous discutons les résultats ainsi que les perspectives de généralisation et les implications pour l’action publique
Evaluating the potential of the Time-SIFT approach using Pléiades satellite imagery for 3D change detection
No full textInternational audienceOptical satellite remote sensing images allow the analysis of topographic change detection based on digital elevation model differencing. Accurate change detection requires co-registration of 3D models derived from multitemporal datasets, so far, usually achieved with external reference data or manual intervention. Based on structure from motion photogrammetric algorithms, co-registering images from different epochs together by extracting multitemporal tie-points, such as the timescale-invariant feature transform (SIFT) approach, has been proven to be efficient for aerial images. We propose a first test of the time-SIFT approach on Pléiades tristereoscopic satellite imagery, covering the coastal plain in northeastern Tunisia. The multitemporal tie-points, coupled with the rational polynomial coefficient models of all the images, are refined in a joint bundle adjustment routine. The accuracy of the derived digital elevation models is assessed in absolute (using external ground truth data) and relative (between epochs). The time-SIFT approach reduces the normalized median absolute deviation from 1.80 to 1.14 m when compared with the classical approach. Our results demonstrate that the time-SIFT approach can be extended for change detection analysis using Pléiades images, without ground control points or a posteriori co-registration, which paves the way to automated investigation of time series of past and future 3D satellite datasets. We highlight the application of the time-SIFT approach to Pléiades images leveraging their high spatial resolution for change detection
Recrutement actif de seniors socio-économiquement défavorisés pour des ateliers de prévention : la procédure INVITE
No full textInternational audienceIntroduction: The risk of aging in poor health is greater among disadvantaged people, but they benefit less from health prevention actions focused on diet and physical activity.Purpose of the study: The INVITE research-action aims to [1] develop an active recruitment procedure to encourage older adults identified as disadvantaged to attend diet and physical activity prevention workshops in the French region Provence-Alpes Côte d'Azur (PACA), [2] evaluate the feasibility and acceptability of this procedure, and [3] measure the effective participation in the workshops of the identified older adults.Results: The INVITE procedure was co-developed by researchers, social workers, and older adults. It includes six steps: identification, invitation letter, telephone contact, home visit, phone call confirmation, and welcome session during the workshop. A pre-test phase made it possible to identify the barriers facing older adults and their motivations at each step, and thus to improve the procedure. The evaluation phase of the effective participation showed that, for 9 workshops, 47 home visits were carried out and 11 older adults participated in the workshops. Conclusion: The INVITE procedure is well received and makes it possible to reach out to disadvantaged older adults and bring them to prevention workshops. Since the prevention workshops promote social diversity, this procedure could be an effective lever to avoid widening social inequalities in health. A larger-scale deployment would help to better characterize participants’ sociodemographic profiles and to evaluate costs.Introduction : Le risque de vieillir en mauvaise santé est plus important chez les personnes défavorisées, or elles bénéficient moins des actions de prévention sur l’alimentation et l’activité physique destinées aux seniors. But de l’étude : La recherche-action INVITE a pour objectifs [1] de développer une procédure de recrutement actif visant à inciter des seniors repérés comme défavorisés à se rendre à des ateliers de prévention sur l’alimentation et l’activité physique en région Provences-Alpes Côte d’Azur (PACA), [2] d’évaluer la faisabilité et l’acceptabilité de cette procédure, et [3] de mesurer la participation effective aux ateliers des seniors ainsi repérés. Résultats : La procédure INVITE a été développée en co-construction entre chercheurs, médiateurs sociaux et seniors. Elle comporte 6 étapes : repérage, envoi d’un courrier d’invitation, contact téléphonique, visite à domicile, confirmation téléphonique, accueil lors de l’atelier. Une phase de pré-test a permis d’identifier les freins et motivations des seniors à chaque étape et ainsi d’améliorer la procédure. La phase d’évaluation de la participation effective a montré que, pour 9 ateliers, 47 visites à domicile ont été effectuées et 11 seniors ont participé aux ateliers. Conclusions : La procédure INVITE est globalement bien acceptée et a permis d’aller vers des seniors défavorisés pour les amener vers des ateliers de prévention. Cette procédure pourrait être un levier efficace pour éviter de creuser les inégalités sociales de santé puisqu’elle favorise la mixité sociale dans les ateliers de prévention. Un déploiement à plus grande échelle permettrait de préciser les profils recrutés et d’évaluer les coûts
Impact de différentes techniques de vinification sur les cépages résistants
No full textInternational audienceLes cépages dits « résistants » sont issus de croisements entre Vitis vinifera et des espèces Vitis nord-américaines ou asiatiques. En viticulture, ces cépages soulèvent un intérêt croissant en raison de leur résistance aux maladies de la vigne, qui permet de réduire drastiquement l’usage des pesticides. Toutefois, leur adoption rencontre de nombreux obstacles, notamment liés à la qualité de leurs vins. Les thiols sont des arômes naturellement trouvés dans les raisins sous la forme de précurseurs aminés. Libérés pendant la fermentation, ils apportent au vin des notes fruitées et exotiques recherchées. Dans les baies, la synthèse des précurseurs de thiols est liée à des mécanismes de défense contre les stress oxydatifs, mais certains thiols peuvent aussi se former pendant la transformation des baies en moût.6 Certains traitements préfermentaires opérées sur les grappes, tels que les macérations sous atmosphère inerte et le passerillage, ou sur les moûts, telle que la cryomacération, ont permis d’augmenter les teneurs en précurseurs chez les cépages V. vinifera. La présence de précurseurs de thiols a été rapportée chez les cépages résistants,12 mais le potentiel des approches préfermentaires pour améliorer leur concentration dans les moûts avant la fermentation n’a pas été étudiée. Dans ce contexte, les hypothèses suivantes ont été posées pour la présente étude : - Les traitements de macération sous gaz (CO2, N2) et le passerillage, appliqués à des grappes entières (baies vivantes) favorisent la synthèse de précurseurs de thiols dans les baies en amont de la fermentation- La cryomacération, opérée sur des baies égrappées et foulées (transformées) favorise l'extraction des précurseurs de thiols dans le moût en amont de la fermentation mais limite la formation de nouveaux précurseurs.Afin de valider ces hypothèses, des traitements préfermentaires ont été conduit sur les cépages résistants Vidal et Frontenac gris, avec un suivi des précurseurs de thiols par LC-MS/MS Orbitra
Convergent evidence for the temperature-dependent emergence of silicification in terrestrial plants
No full textInternational audienceResearch on silicon (Si) biogeochemistry and its beneficial effects for plants has received significant attention over several decades, but the reasons for the emergence of high-Si plants remain unclear. Here, we combine experimentation, field studies and analysis of existing databases to test the role of temperature on the expression and emergence of silicification in terrestrial plants. We first show that Si is beneficial for rice under high temperature (40 °C), but harmful under low temperature (0 °C), whilst a 2 °C increase results in a 37% increase in leaf Si concentrations. We then find that, globally, the average distribution temperature of high-Si plant clades is 1.2 °C higher than that of low-Si clades. Across China, leaf Si concentrations increase with temperature in high-Si plants (wheat and rice), but not in low-Si plants (weeping willow and winter jasmine). From an evolutionary perspective, 77% of high-Si families (>10 mg Si g−1 DW) originate during warming episodes, while 86% of low-Si families (<1 mg Si g−1 DW) originate during cooling episodes. On average, Earth’s temperature during the emergence of high-Si families is 3 °C higher than that of low-Si families. Taken together, our evidence suggests that plant Si variation is closely related to global and long-term climate change
Not the brightest earthworm in the genus: two non-bioluminescent Avelona (Lumbricidae, Crassiclitellata) with description of a new species
No full textInternational audienceSeveral new earthworm species have been described in France in the last decade, but the Western peri-Alpine region, despite hosting several endemic species, has received little attention. A recently discovered earthworm species from this region was found to be a close relative to Avelona ligra and Allolobophora s.l. zicsii after molecular phylogenetics (based on the molecular markers COI, 16S, ND1, 28S and 12S) and described as Avelona yvesi sp. nov. Morphological study of Av. yvesi sp. nov., Avelona zicsii comb. nov. and Av. ligra allowed to provide an improved diagnosis of the genus, highlighting a wide variability in spermathecae and nephridial morphology. These species reinforce the evolutionary significance of their range as a putative refuge of a pre-glacial diversity, show contrasting distribution patterns which could be attributed to historical or ecological causes, and provide new chances to study bioluminescence in Av. ligra with their closest, non-bioluminescent relatives
A multi-scale analysis of drought effects on intrinsic water use efficiency in a Mediterranean evergreen oak forest
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Reduced Water Availability to Mothers and Embryos Has Little Effect on Offspring Phenotypes in an Invasive Lizard
No full textInternational audienceWater availability has critical impacts on numerous physiological functions in all organisms and can have different effects across life stages. For example, water available to reproductive females can influence offspring production, and has the potential to influence how early‐stage offspring (e.g., embryos) respond to moisture in their developmental environment. In this study, we use the brown anole lizard ( Anolis sagrei ) to examine the effects of water availability on reproductive investment. We tested the hypothesis that water available to mothers influences embryonic development under different levels of moisture in their incubation environment. We demonstrate that a substantial reduction in water availability to mothers (~70% reduction) has no observable effect on fecundity, egg size, or egg hydration. We also provide evidence that our water restriction to mothers does not influence how embryos respond to moisture conditions during egg incubation. However, moisture in the egg incubation substrate positively affected egg water uptake, egg hatching success and hatchling body size (but not hatchling hydration). Overall, our study shows that reproduction in adult female A. sagrei is robust to variation in water availability, but survival during early life stages is sensitive to this variable. Thus, the effect of water availability on different fitness components varies between life stages
Integrating pollinators’ movements into pollination models
No full textInternational audienceAccurate prediction of pollination processes is a key challenge for sustainable food production and the conservation of natural ecosystems. For many plants, pollen dispersal is mediated by the foraging movements of nectarivore animals. While most current models of pollination ecology assume random pollen movements, studies in animal behaviour show how pollinating insects, birds and bats rely on sensory cues, learning and memory to visit flowers, thereby producing complex movement patterns. Building upon a brief review of pollination and movement models, we argue that we need to better consider pollinators’ cognition to improve predictions of animal-mediated pollination across all spatial scales, from individual flowers, to plants, habitat patches and landscapes. We propose a practical roadmap for the integration of behavioural models into pollination models and discuss how this synthesis can refine predictions regarding plant mating patterns and fitness. Such crosstalk between animal behaviour and plant ecology research will provide powerful mechanistic tools to predict and act on pollination services in the context of a looming crisis
“The bigger picture beyond the pump”: Engaging farmer’s in Collaborative Groundwater Management in California
No full textInternational audienceIn response to the limitations of the "open-access" groundwater management regime, exacerbated by climate change, many countries are shifting towards a regulated access paradigm (Rouillard et al., 2021). This new governance approach ranges from "state-centered" to forms of "collaborative management" or "comanagement" (Molle, Closas, 2020), where farmers must now cooperate with stakeholders representing diverse interests (drinking water supply, protection of groundwater-dependent ecosystems, etc.). In California, the Sustainable Groundwater Management Act (SGMA) of 2014 embodies this shift (Harter, 2020), with the creation of Groundwater Sustainability Agencies (GSAs), responsible for developing sustainable management plans that engage a wide variety of stakeholders. Based on a qualitative survey (~50 respondents) conducted in 2023-24 in two groundwater basins in north California, we examine how this new governance model effectively involves farmers in the development of communities of interest and collective action for sustainable groundwater management. Our analysis focuses on two key aspects: First, we evaluate the social learning outcomes of the participatory process, examining how this experience is able to foster a shared and renewed understanding of an invisible and complex resource, deeply intertwined with socio-economic, political and cultural dimensions. Specifically, we investigate how the process facilitated the co-construction of a common vision regarding groundwater dynamics, the interdependencies between groundwater and surface water, and between uses and the relationships among various uses and users - capturing the "bigger picture beyond the pump". Additionally, we examine how this collaborative effort was able to build new forms of cooperation, grounded in mutual recognition of legitimacy, and the creation of shared values. Second, we explore how this process challenges the notions of collectives and communities of interest within the agricultural sector itself. Participation reshapes relationships among farmers - between large and small farms, and between farmers with different practices and environmental sensitivities. It redefines forms of collective action within the farming community, reinforcing or creating coalitions of interests, and elaborating new strategies to protect farmer’s “water rights”, in the face of evolving political dynamics and shifting power relations