Réduire l’emploi des produits phytosanitaires en verger de pommier. Les enseignements du réseau national EXPE Ecophyto Pomme.

Ce numéro est constitué d’articles de synthèse des projets DEPHY EXPE publiés à l’occasion du colloque national DEPHY, qui s’est déroulé les 13 et 14 novembre 2018 à la Cité des Sciences et de l'Industrie (Paris). Nous vous invitons à découvrir le bilan et les enseignements des 21 projets conduits sur la période 2012-2017.27 production systems, located on six places in France, compose the national apple network EXPEEcophyto. The study aims to acquire technical and economic references to reduce the use of pesticidesand limit detectable residues on fruits. The main mobilized technics are genetics (varietal resistance),cultural practices (prophylaxis), biocontrol products, efficiency (models and decision thresholds, dosesmodulation, spraying techniques), physical protections (Alt’Carpo nets, rain covers), mechanization(mechanical weed control), beneficial insects (released or by preservation). The economic systems areled with an integrated fruit protection program or in an organic way.On an average of five years, 12 systems (on 19) reached a percentage of reduction of the total chemicaltreatment frequency indicator (in French : IFT) of more than 50 % with regard to the reference. On theother hand, just 7 systems are considered as economic and efficient systems (in French : SCEP2).Among those, only the 3 organic systems present an equal or upper economic profit than the incurredproduction costs.27 systèmes de culture, répartis sur six sites en France, constituent le réseau national EXPE EcophytoPomme. L’étude vise à acquérir des références techniques et économiques sur les moyens permettantde réduire l’emploi des produits phytosanitaires et de limiter les résidus détectables sur les fruits. Lesprincipaux leviers mobilisés sont la génétique (résistance variétale), le contrôle cultural (prophylaxie), lebiocontrôle, l’efficience (outils d’aide à la décision et seuils d’intervention, modulation des doses,techniques de pulvérisation), la protection physique (filet Alt’Carpo, bâches anti-pluie), la mécanisation(désherbage mécanique), la lutte biologique (par lâchers et par conservation). Les systèmes économesétudiés sont conduits en protection fruitière intégrée ou en agriculture biologique (AB).Sur une moyenne de cinq campagnes, 12 systèmes (sur 19) ont atteint un pourcentage de réduction del’IFT chimique total de plus de 50 % par rapport à une modalité dite de « Base ». Par contre,uniquement 7 systèmes sont considérés comme des systèmes économes et performants (SCEP2).Parmi ceux-là, seuls les 3 systèmes conduits en AB présentent un produit brut égal ou supérieur auxcharges engagées

Multi-objective Evolutionary Algorithms to Investigate Neurocomputational Issues: The Case Study of Basal Ganglia Models

International audienceThe basal ganglia (BG) are a set of subcortical nuclei involved in action selection processes. We explore here the automatic parameterization of two models of the basal ganglia (the GPR and the CBG) using multi-objective evolutionary algorithms. We define two objective functions characterizing the supposed winner-takes-all functionality of the BG and obtain a set of solutions lying on the Pareto front for each model. We show that the CBG architecture leads to solutions dominating the GPR ones, this highlights the usefulness of the CBG additional connections with regards to the GPR. We then identify the most satisfying solutions on the fronts in terms of both functionality and plausibility. We finally define critical and indifferent parameters by analyzing their variations and values on the fronts, helping us to understand the dynamics governing the selection process in the BG models

Peer substance use overestimation among French university students: a cross-sectional survey

<p>Abstract</p> <p>Background</p> <p>Normative misperceptions have been widely documented for alcohol use among U.S. college students. There is less research on other substances or European cultural contexts. This study explores which factors are associated with alcohol, tobacco and cannabis use misperceptions among French college students, focusing on substance use.</p> <p>Methods</p> <p>12 classes of second-year college students (n = 731) in sociology, medicine, nursing or foreign language estimated the proportion of tobacco, cannabis, alcohol use and heavy episodic drinking among their peers and reported their own use.</p> <p>Results</p> <p>Peer substance use overestimation frequency was 84% for tobacco, 55% for cannabis, 37% for alcohol and 56% for heavy episodic drinking. Cannabis users (p = 0.006), alcohol (p = 0.003) and heavy episodic drinkers (p = 0.002), are more likely to overestimate the prevalence of use of these consumptions. Tobacco users are less likely to overestimate peer prevalence of smoking (p = 0.044). Women are more likely to overestimate tobacco (p < 0.001) and heavy episodic drinking (p = 0.007) prevalence. Students having already completed another substance use questionnaire were more likely to overestimate alcohol use prevalence (p = 0.012). Students exposed to cannabis prevention campaigns were more likely to overestimate cannabis (p = 0.018) and tobacco use (p = 0.022) prevalence. Other identified factors are class-level use prevalences and academic discipline.</p> <p>Conclusions</p> <p>Local interventions that focus on creating realistic perceptions of substance use prevalence could be considered for cannabis and alcohol prevention in French campuses.</p

Ontogeny of central serotonergic neurons in the directly developing frog, Eleutherodactylus coqui

Embryonic development of the central serotonergic neurons in the directly developing frog, Eleutherodactylus coqui , was determined by using immunocytochemistry. The majority of anuran amphibians (frogs) possess a larval stage (tadpole) that undergoes metamorphosis, a dramatic post-embryonic event, whereby the tadpole transforms into the adult phenotype. Directly developing frogs have evolved a derived life-history mode where the tadpole stage has been deleted and embryos develop directly into the adult bauplan. Embryonic development in E. coqui is classified into 15 stages (TS 1–15; 1 = oviposition / 15 = hatching). Serotonergic immunoreactivity was initially detected at TS 6 in the raphe nuclei in the developing rhombencephalon. At TS 7, immunopositive perikarya were observed in the paraventricular organ in the hypothalamus and reticular nuclei in the hindbrain. Development of the serotonergic system was steady and gradual during mid-embryogenesis. However, starting at TS 13 there was a substantial increase in the number of serotonergic neurons in the paraventricular, raphe, and reticular nuclei, a large increase in the number of varicose fibers, and a differentiation of the reticular nuclei in the hindbrain. Consequentially, E. coqui displayed a well-developed central serotonergic system prior to hatching (TS 15). In comparison, the serotonergic system in metamorphic frogs typically starts to develop earlier but the surge of development that transpires in this system occurs post-embryonically, during metamorphosis, and not in the latter stages of embryogenesis, as it does in E. coqui . Overall, the serotonergic development in E. coqui is similar to the other vertebrates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47526/1/429_2005_Article_22.pd

Intratelencephalic corticostriatal neurons equally excite striatonigral and striatopallidal neurons and their discharge activity is selectively reduced in experimental parkinsonism

Striatonigral and striatopallidal neurons form distinct populations of striatal projection neurons. Their discharge activity is imbalanced after dopaminergic degeneration in Parkinson's disease. Striatal projection neurons receive massive cortical excitatory inputs from bilateral intratelencephalic (IT) neurons projecting to both the ipsilateral and contralateral striatum and from collateral axons of ipsilateral neurons that send their main axon through the pyramidal tract (PT). Previous anatomical studies in rats suggested that IT and PT inputs preferentially excite striatonigral and striatopallidal neurons, respectively. Here we used electrophysiological criteria to identify them with antidromic stimulations. We show that the spontaneous discharge activity of IT neurons is depressed, whereas that of PT neurons is not affected in the rat cortex ipsilateral to 6-hydroxydopamine injection. However, our functional experiments do not support the hypothesis of a differential cortical input to striatal pathways. Firstly, although the conduction velocity of PT neurons is 4.6 times faster than that of IT neurons, identified striatopallidal and striatonigral neurons exhibit identical latencies of their spike responses to electrical stimulation of the ipsilateral cortex. Secondly, although PT neurons are ipsilateral, both striatal populations exhibit similar sensitivity to the stimulation of the ipsilateral and contralateral cortex. We suggest that IT neurons provide the main excitatory input to both striatal populations and that the corticostriatal PT input is weaker. Therefore, our functional data do not support our previous hypothesis that the deficit of IT neurons associated with the dopaminergic depletion might contribute to the striatal imbalance. This imbalance might rather result from intrinsic striatal mechanisms

Premier inventaire ichthyologique de la partie basse de la Seine

Extrait de documentEn septembre 96, un inventaire des espèces de poissons a été effectué par l'ESTURIAL, du barrage de Poses, à la baie de Seine. Les engins ont été choisis de façon à permettre la capture de poissons de toutes tailles et sur toute la tranche d'eau. Sur le secteur situé entre Poses et Rouen on rencontre 9 espèces avec des individus de taille moyenne et une densité très faible. De Rouen à Caudebec, on recense 12 espèces dont certaines estuariennes ou marines. La taille est en baisse par rapport à l'amont et la densité très faible. De Caudebec à Honfleur, on rencontre 11 espèces et de nombreux juvéniles d'espèces marines, ce qui explique la très petite taille moyenne des individus, la densité est par contre plus importante qu'à l'amont. Dans la baie de Seine, la diversité spécifique augmente, on y rencontre l'ensemble des espèces marines de la région. De l'amont vers l'aval on passe progressivement d'un peuplement dulçaquicole à un peuplement marin, on note la présence dans l'ensemble des zones d'espèces migratrices et l'incursion jusque relativement loin en amont de juvéniles de bar

Cell-free synthesis of functional human epidermal growth factor receptor: Investigation of ligand-independent dimerization in Sf21 microsomal membranes using non-canonical amino acids

Cell-free protein synthesis systems represent versatile tools for the synthesis and modification of human membrane proteins. In particular, eukaryotic cell-free systems provide a promising platform for their structural and functional characterization. Here, we present the cell-free synthesis of functional human epidermal growth factor receptor and its vIII deletion mutant in a microsome-containing system derived from cultured Sf21 cells. We provide evidence for embedment of cell-free synthesized receptors into microsomal membranes and asparagine-linked glycosylation. Using the cricket paralysis virus internal ribosome entry site and a repetitive synthesis approach enrichment of receptors inside the microsomal fractions was facilitated thereby providing analytical amounts of functional protein. Receptor tyrosine kinase activation was demonstrated by monitoring receptor phosphorylation. Furthermore, an orthogonal cell-free translation system that provides the site-directed incorporation of p-azido-L-phenylalanine is characterized and applied to investigate receptor dimerization in the absence of a ligand by photo-affinity cross-linking. Finally, incorporated azides are used to generate stable covalently linked receptor dimers by strain-promoted cycloaddition using a novel linker system

Suivi de la population d’esturgeons européens en milieu naturel en 2014 : chapitre VII

Extrait de documentObjectifs : suivre l’état de la population, documenter l'évolution des différentes cohortes, analyser l'intégration des poissons issus de reproductions ex situ et renseigner les captures accidentelles