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Advancing mycorrhizal research for sustainable ecosystem and agricultural practices. Editorial
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616544/)International audienc
Woody habitats and dry conditions limit pest occurrence in vineyards
No full textInternational audienceLandscape heterogeneity, notably the amount of semi‐natural habitats, has been found to enhance natural enemies of crop pests and biological pest control in agricultural landscapes. Moreover, increasing host‐crop areas can directly affect the dynamics of pest or pathogen populations by providing them with more resources. However, the actual beneficial impacts of diversifying agricultural landscapes on pest or pathogen population levels are still poorly demonstrated, limiting farmers' adoption of such approaches. Here, using national‐scale data collected between 2014 and 2019 and Bayesian spatial models, we investigated how land use in the municipality and meteorological context affected the occurrence of two main pest and pathogen in vineyards: downy mildew (632 fields per year) and grape berry moth (225 fields per year). Our analysis revealed that the probability of occurrence of downy mildew and grape berry moth decreased as the percentage of woodland in the municipality increased. Additionally, we found that the probability of occurrence of downy mildew strongly depended on the meteorological context, as the probability of occurrence of downy mildew increased with the mean rainfall during spring and summer. Our analysis revealed no effect of the share of organic farming vineyard in the municipality on pest pressure. Synthesis and applications. Our study demonstrates that diversifying vineyard‐dominated landscapes by increasing the area of woody habitats could limit the occurrence of downy mildew and grape berry moth, which are responsible for most pesticide applications in vineyards. This work provides a significant step forward in the design of pest‐suppressive landscapes that highlight the key role of woody habitat maintenance in vineyard landscapes. Future work should now investigate how such nature‐based solutions could provide other benefits to farmers and the entire society
From structure to function: predicting mass transfer in cellulose-based multilayer packaging materials
No full textInternational audiencePredicting barrier properties of multilayer materials is essential for designing effective food packaging. Although resistance-based models are commonly used, their applicability to complex structures, such as polymer-coated paper/cardboard, remains underexplored. This study investigates the predictive ability of these models for multilayer systems composed of cellulosic substrates laminated with poly(3-hydroxybutyrate-co-3hydroxyvalerate) (PHBV). Four model materials were designed to cover a wide span of barrier properties. PHBV lamination significantly improved barrier properties (up to a factor of 10 5 ), primarily through the formation of an impregnated layer rather than a continuous film. Spatial heterogeneities within the samples were integrated into the modeling approaches. Different structural assumptions were considered. None of the models accurately predicted the barrier properties of all PHBV-laminated samples, highlighting the influence of additional factors such as interfacial adhesion, polymer crystallinity, and local defects. This work proposes, for the first time, an experimental estimation of the impregnated layer's permeability (from 10 -15 to 10 -13 mol.m.m -2 . s -1 .Pa -1 for oxygen permeability to 10 -15 -10 -12 mol.m.m -2 .s -1 .Pa -1 for water vapor permeability). These findings indicate that a free polymer layer is not strictly required to achieve substantial barrier enhancement and underscore the central role of the impregnated layer in mass transfer, reinforcing the need to refine existing predictive models.</div
Metric space valued Fréchet regression
No full textWe consider the problem of estimating the Fréchet and conditional Fréchet mean from data taking values in separable metric spaces. Unlike Euclidean spaces, where well-established methods are available, there is no practical estimator that works universally for all metric spaces. Therefore, we introduce a computable estimator for the Fréchet mean based on random quantization techniques and establish its universal consistency across any separable metric spaces. Additionally, we propose another estimator for the conditional Fréchet mean, leveraging data-driven partitioning and quantization, and demonstrate its universal consistency when the output space is any Banach space
Political Representation Gaps and Populism
No full textNational audiencePopulists are often defined as those who claim that they fill "political representation gaps" -differences between the policymaking by established parties and the "popular will." Research has largely neglected to what extent this claim is correct. I study descriptively whether representation gaps exist and their relationship with populism. To this end, I analyze the responses of citizens and parliamentarians from 27 European countries to identical survey policy questions, which I compile and verify to be indicative of voting in referendums. I find that policymaking represents the economic attitudes of citizens well. However, I document that the average parliamentarian is about 1SD more culturally liberal than the national mean voter. This cultural representation gap is systematic in four ways: i) it arises on nearly all cultural issues, ii) in nearly all countries, iii) nearly all established parties are more culturally liberal than the national mean voter, and iv) all major demographic groups tend to be more conservative than their parliamentarians. Moreover, I find that demographic differences between voters and parliamentarians or lack of political knowledge cannot fully account for representation gaps. Finally, I show that right-wing populists fill the cultural representation gap
Reduced snow cover at the alpine treeline: resistance and recovery of saplings
No full textInternational audienceSummary At high elevations, tree saplings and shrubs are usually protected by mid‐winter snow cover, although climate change is expected to extend the snow‐free (SF) period. Exposure to winter drought, freeze–thaw events and freezing temperatures will therefore increase, inducing damages to the hydraulic system and to living cells, resulting in reduced growth and increased mortality. A snow removal experiment was carried out at 1700 m. above sea level on saplings of five different species ( Acer pseudoplatanus , Juniperus communis , Larix decidua , Picea abies and Sorbus aucuparia ). Stem diameter was continuously monitored and compared with spring hydraulic conductivity (PLC spring ), living cell mortality (PLD spring ), nonstructural carbohydrates (NSCs), growth and survival rates. Under SF conditions, saplings had higher PLC spring and higher PLD spring , and thus experienced greater winter dehydration, resulting in lower growth compared with snow‐covered saplings. Summer mortality was strongly correlated with PLC spring and PLD spring . These two key ecophysiological parameters predicted the risk of mortality in all species, whereas only PLD spring reduced growth. By monitoring stem diameter during winter, we have defined indices to quantify resistance and recovery of woody plants under increased frost pressure. Recovery strategies such as resprouting or embolism repair were critical for survival, highlighting the potential vulnerability of saplings to climate change at high elevations
Monochain HSMM
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616072/)International audienceThis chapter presents general HSMM formalism and well-known particular cases. It starts with a gentle introduction to illustrate the main notions and notations for a toy example. The chapter then introduces the maximum likelihood estimation (MLE) for HSMM, the likelihood expression and evaluation, asymptotic properties of MLE and expectation-maximization (EM) algorithm for MLE computation. It presents recent results on two topics seldom addressed for HSMMs: the definition of reliability indicators and introduction of mixed effects into HSMM components, with the latter presenting a thorough survey of the literature. Some works considered real-valued hidden states or continuous time. When the underlying chain is a Markov chain (instead of a semi-Markov chain), the observation and the hidden spaces are general and the time is discrete, then the corresponding models are known as "state space models"
Conception et développement d’un monitoring avec Node-RED pour visualiser les données pour le projet ECOLOGGING.
No full textThis report describes all the stages of the development and design of a secure monitoring system using the Node-RED software for ECOLOGGING instrumented stations.Ce rapport décrit toutes les étapes du développement/conception d'un monitoring sécurisé avec le logiciel Node-RED pour les stations instrumentées ECOLOGGING
Les interfaces graphiques pour la modélisation hydrologique. De la préparation des données à la prévision des débits
No full textInternational audienceFor nearly ten years, the Hydrology team at the HYCAR research unit (Antony) has been designing and developing graphical interfaces dedicated to hydrological modeling. These tools are intended to facilitate the entire modeling process — from the preparation and validation of input data to the visualization and interpretation of results, including hydrological forecasting. Designed both as educational resources and decision-support tools, these interfaces help improve understanding and interpretation of streamflow simulations across watersheds.Depuis près de dix ans, l’équipe Hydrologie des bassins versants de l’U.R. HYCAR (Antony) conçoit et développe des interfaces graphiques dédiées à la modélisation hydrologique. Ces outils visent à faciliter l’ensemble du processus de modélisation, depuis la préparation et la validation des données d’entrée jusqu’à la visualisation et l’interprétation des résultats, notamment des prévision hydrologiques. Pensées comme supports pédagogiques et des outils d’aide à la décision, ces interfaces contribuent à améliorer la compréhension l'interprétation des simulations de débits sur les bassins versants
Validation of a representative sampling protocol for studying grape berry microbiota at the plot scale
No full textData availability: Raw sequences have been deposited at NCBI under the BioProject accession number PRJNA1327833.International audienceIn viticulture, a comprehensive understanding of the grape microbiota is crucial, as it influences various aspects of the winemaking process, from vine health and grape development to fermentation dynamics and the final sensory profile of the wine. Monitoring these communities helps optimize vineyard practices and ensure product authenticity. Metagenetics is a fast culture-independent approach that allows identification of the microorganisms present in grape berries' microbiota at the genus or species level. In this context, it is crucial to assess the quality of sampling methods in terms of their representativeness of the diversity of microbial communities on grape berries at the plot level. In this study, the microbiota of the variety Artaban was examined. This variety is resistant to powdery mildew and tolerant to downy mildew. Two sampling methods for studying microbiota were investigated by forming two groups: one that pooled the microbiota of 10 vines, and another that studied the microbiota of each vine separately.</div