Portail Hal-l'Institut Agro Rennes-Angers
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Change of support for zero-inflated data: deriving fine-scale species distribution inferences from spatially aggregated data
No full textInternational audienceIn environmental sciences, data are often available at a coarse resolution. This can result in a mismatch between the data resolution and the resolution at which process inference should be made. This misalignment, usually named change of support (COS), can lead to biased inference if not addressed appropriately. Yet, solutions to the COS issue have only been proposed for a limited number of observational distributions (e.g. Poisson or Gaussian), which narrows their range of application. Motivated by a fisheries case study, we introduce a hierarchical method addressing COS for zero-inflated data with highly skewed tails. Such data are common in environmental sciences but are not handled by existing COS methods. Our approach requires the spatial locations of point-level data to be known and considers that aggregated data are convolutions of these point-level data. We assess the accuracy of our method through a simulation study. Subsequently, we apply our model to a real case study, here common sole in the Bay of Biscay. Our findings illustrate that the model provides better estimates and predictions than the ad hoc method used for geoprocessing aggregated data. Specifically, the effect of the environment on the species distribution is better evidenced with our model
Single-time fertilization of controlled release blended fertilizer optimizes soil nitrogen distribution and root characteristics to increase conventional japonica rice (Oryza sativa L.) grain yield and nitrogen use efficiency
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Sprouted grains fermentation: a comprehensive review of current knowledge, benefits, challenges, and perspectives
No full textInternational audienceSprouted seeds are attracting growing interest because of their improved digestibility, high nutritional value, variety, low cost and ease of production. However, their microbiological fragility and elevated levels of certain anti-nutritional factors can sometimes pose problems for their use in both food and feed. Recent research has shown that combining fermentation with germination can effectively solve these problems. Fermentation not only improves nutritional value by lowering levels of anti-nutritional factors, but also improves microbiological safety, making it a promising approach to extending shelf life. Additionally, fermented sprouted seeds have beneficial properties may be of use in the formulation of functional foods, particularly for managing metabolic diseases such as diabetes. Despite these positive points, there is still room for improvement in the fermentation of sprouted seeds. This literature review explores current knowledge of seed germination, the advantages of fermenting sprouted seeds, and discusses the disadvantages and potential axes for improvement
MRI investigation of particle-scale digestion mechanisms in solid foods
No full textInternational audienceSolid food enters the stomach in the form of a cohesive bolus made of particles ranging in diameter from 0 to 5 mm. Depending on their inner structure and composition, digestion kinetics may be limited by the diffusion of the digestive fluids (e.g. enzyme and pH gradients), and/or the resistance of microstructures to enzymatic attack (e.g. gluten and cell walls). This study aimed to investigate the mechanisms occurring at the scale of food particles that govern the degradation of complex structures. MRI was employed to characterise changes in the composition and structure at different scales (from molecules to particles) during in vitro gastrointestinal digestion. The matrix effects of bread (as a model of starchy products) and apples (as a model of fleshy fruit) were studied. Experiments were performed using a 1.5 T whole-body MRI imager (Avanto, Siemens) and an original remote-controlled setup validated for large solid food particles. In bread, 3D morphological MRI and T₂ mapping revealed changes in structure, fluid ingress, and progressive pore filling. Both peripheral and internal structural evolution correlated well with the release of peptides and starch hydrolysis products. This indicates that bread digestion involves not only surface erosion but also internal weakening. For apple, T₂ and microporosity maps showed lower values at the periphery, indicating spatial variation associated with fluid and enzyme penetration. This real-time high-resolution MRI approach offers a novel tool to study digestion mechanisms at the particle scale across diverse foods
Intégrer une pratique artistique dans une progression pédagogique pour préparer les futurs ingénieurs agronomes à la complexité des enjeux sociétaux : l'élevage au coeur d'un procès théâtral fictif
No full textInternational audienceThis article presents a pedagogical approach integrating theater to prepare future agronomy engineers for the complexity of societal issues related to livestock farming. Offered at the Institut Agro, this program enables students, through collective exercises, to create and perform a fictional trial on this theme. The approach fosters transversal skills such as argumentation, emotional management, and critical thinking. A typology of student profiles reveals a diversity of experiences. The results show that theatrical practice promotes both individual and collective empowerment, while developing essential skills to address societal and professional controversies.Cet article présente une démarche pédagogique intégrant le théâtre pour préparer les futurs ingénieurs agronomes à la complexité des enjeux sociétaux liés à l'élevage. Proposé à l'Institut Agro, ce parcours permet, par des exercices collectifs, de créer et représenter un procès fictif sur ce thème. L'approche développe des compétences transversales comme l'argumentation, la gestion des émotions et l'esprit critique. Une typologie des profils étudiants révèle une diversité des vécus. Les résultats montrent que la pratique théâtrale favorise l'émancipation individuelle et collective, tout en développant des compétences essentielles pour faire face aux controverses sociétales et professionnelles
Angers : première ville de France dans les classements où il fait bon apparaître
No full textAtlas social d'Angers« Reconnue régulièrement Ville la plus verte de France, Angers s’appuie sur un patrimoine paysager unique : une densité d’espaces de nature deux fois plus importante que la moyenne nationale, un investissement continu pour la création et l’entretien zéro phyto des espaces verts ». Extrait de la page Internet de Destination Angers. Comment faut-il lire ces palmarès souvent très à l’avantage de la cité du Roi René ? Dans un ouvrage stimulant sur l’idée de « qualité » et les démarches de labellisation/quantification dont elle est l’objet, un essayiste remet en cause la capacité des indicateurs à quantifier les qualités et argumente de la nécessité de les « libérer » des normes standardisées (Chabot)
Le concept d’acceptation sociale à l’épreuve d’un conflit : pêche et éolien offshore en baie de Saint-Brieuc
No full textInternational audienceDespite initial cooperation, the offshore wind farm in the Bay of Saint-Brieuc (France) has faced strong opposition from professional fishermen. Reflecting on 20 years of a collaborative and conflictual journey, we analyze the shift towards conflict while highlighting turning points and their determining factors. At stake is the localization of an innovative technology and of a general interest : this process is analyzed using the economics of proximities and the actor-network theory. This study prompts us to discuss the concept of social acceptance and the acceptance scales proposed in the literature, particularly considering the potential boomerang effect of appropriation, usually presented as the highest level of acceptance. We also emphasize that, since such a project is subject to multiple eco-socio-technical uncertainties, acceptance is constantly being tested : acceptance is therefore marked by the central role of trust and organized proximities to be built, activable to overcome the tests of acceptability.Malgré une coopération initiale, le projet de parc éolien offshore en baie de Saint-Brieuc a suscité une forte opposition de la part des pêcheurs. Restituant 20 ans d’itinéraire concertatif et conflictuel, nous analysons ce glissement vers le conflit tout en mettant en lumière des points de bascule et le rôle des proximités. Ce qui est en jeu, c’est la territorialisation d’une technologie innovante et de l’intérêt général. Cette étude nous invite à discuter la notion d’acceptation sociale, en prenant en compte le potentiel effet boomerang de l’appropriation, pourtant souvent présentée comme le niveau le plus élevé de l’acceptation. Sans cesse mise à l’épreuve, l’acceptation est notamment déterminée par les dynamiques des proximités et de la confiance
Fostering creativity to design biodiversity-based cropping systems that consider the long term: a participatory framework
No full textInternational audienceBiodiversity-based cropping systems can address sustainability challenges currently faced by agriculture and provide long-term benefits such as climatechange mitigation and other ecosystem services. However, short-term socioeconomic and technical challenges encourage adherence to established paradigms halting the implementation of such systems in farms. In response, we developed a new framework that combines a fictional narrative and information about plant functional ecology to facilitate the co-design of biodiversity-based cropping systems. To demonstrate the interest of this framework, a participatory workshop was conducted in which participants selected crop species based on functional traits and collaboratively designed crop rotations. Both quantitative evaluation of co-designed crop rotations by ecological indices and qualitative evaluation by the satisfaction assessment of the framework by participants were performed. Our approach showed that the two co-designed crop rotations had higher biodiversity than the two reference rotations used in the study: the dominant (maize (Zea mays)wheat (Triticum aestivum)catch crop (white mustard (Sinapis alba)) and a highly diversified rotation designed to reduce the use of pesticides (10 taxonomic species). Using a fictional narrative as a trigger event (being stranded on a deserted island) was instrumental in expanding possibilities and stimulating creativity among the participants, which helped them design diverse crop rotations that contained taxonomical and functional diversity. Our framework demonstrated a potential to co-design biodiversity-based cropping systems by abstraction
Body condition decline in Western european fishes
No full textInternational audienceThe body condition of small pelagic fish has been declining since the early 2000s in several ecosystems, including the Mediterranean Sea and the Bay of Biscay, probably in response to bottom-up control. Possible trends in body condition of demersal and benthic species in the same regions have so far received little attention. Using a North East Atlantic case study (Bay of Biscay and Celtic Sea), we computed Le Cren's relative body condition index for 264,000 fish individuals from 17 species, based on individual length and weight data collected between 2002 and 2022. Using linear models, a decreasing trend in body condition was evidenced for 12 species, while only two species showed an increase. Anchovy (Engraulis encrasicolus), plaice (Pleuronectes platessa), megrim (Lepidorhombus whiffiagonis) and sardine (Sardina pilchardus) have suffered the greatest declines. For these species, individual weight at equivalent size decreased by 3-5 % per decade. The variability between individuals' body condition was mainly explained by sex and sampling season. Among the other variables tested, stock biomass and chlorophyll-a concentration had significant effects on a majority of species, while sea surface temperature did not explain much variability. The declining trend of body condition at the fish community scale could then be partly explained by bottom-up control, but probably also involved complex interactions at the ecosystem scale. Beyond the possible consequences on fish provisioning quality, the prevalence of declining body condition of various fish should be considered as a warning on possible important changes in the overall functioning of marine food-webs