827 research outputs found
Interface between pest risk science and policy : the EPPO perspective
The European and Mediterranean Plant Protection Organisation (EPPO) is an intergovernmental organization responsible for cooperation in plant protection in the European and Mediterranean region. It provides global distribution maps of pests, and intends to identify the areas at risk from new and emerging pests, in the framework of Pest Risk Analyses. EPPO has developed a decision-support scheme for Pest Risk Analysis (DSS) and a computer program (CAPRA) to assist pest risk analysts in running the decisionsupport scheme. Dedicated rating guidance and a Climatic Suitability Risk Mapping Decision-Support Scheme have recently been developed to guide assessors in identifying the potential area of establishment of a pest. All these tools have been developed taking into account both pest risk science available and needs of policy makers. The use of these tools and of mapping software are undertaken within the framework of EPPO Pest Risk Analyses, as illustrated through the examples of Thaumatotibia leucotreta (Lepidoptera) and Apriona germari (Coleoptera)
Processus et mécanismes centrés sur l'inoculum : une approche fonctionnelle et expérimentale de l'épidémiologie végétale
Mon mémoire d'HDR se decompose en cinq parties : la description de mon parcours scientifique ; une synthèse de mes travaux de recherche menés de 2000 à 2015, déclinés en quatre chapitres selon les thématiques et les questions abordées ; mon projet de recherche et d'animation scientifique collective pour les années à venir ; les références bibliographiques ; une sélection de cinq publications majeures en annexe. Au sein de l'équipe d'épidémiologie de l'UMR BIOGER, mes recherches se déclinent actuellement en trois axes : (1) les processus épidémiques, l'initiation et la récurrence des épidémies de septoriose du blé ; (2) la réponse à la temperature de populations de l'agent pathogène Zymospetoria tritici responsable de la septoriose, ses consequences épidémiologiques et le potential d'adaptation au changement climatique : (3) l'épidémiologie fonctionnelle appliquée à la biosécurité, à l'analyse de risques et à la gestion de crises sanitaires en santé végétale
Practical Access to Aromatic Thiocyanates by CuCN-Mediated Direct Aerobic Oxidative Cyanation of Thiophenols and Diaryl Disulfides
International audienceThe practical and mild aerobic oxidative CuCN-mediated cyanation of thiophenols and diaryl disulfides was investigated. The reaction was performed in air at room temperature and reached aromatic thiocyanates in moderate to good yields starting from a broad range of diversely functionalized substrates
Comparative study on the reactivity of propargyl and alkynyl sulfides in palladium-catalyzed domino reactions
International audienceThree types of sulfides bearing a propargyl or an alkynyl moiety have been studied in cyclocarbopalladation/cross-coupling domino palladium-catalyzed sequences. The reactivity of different types of sulfured starting materials has been compared as well as the difference in behavior of these compounds depending on the type of cross coupling ending the domino sequence. It appeared that these cascades were constantly more efficient on the propargyl benzyl thioether. In addition, it has been demonstrated that domino sequences ending with Stille, SuzukieMiyaura, or MizorokieHeck lead efficiently and selectively to the desired cyclized products. Notably, when the introduction of an alkyne is targeted at the end of the cascade, it appeared that the Sonogashira coupling leads every time to the desired cyclic product in the mixture with the product resulting from the direct coupling between the aryl moiety of the substrate and the alkyne used as partner. Finishing the domino sequence with a Stille coupling instead of a Sonogashira one allowed improving significantly the ratio of the mixture in favor of the desired cyclized compound
Réalisation d'un dispositif expérimental pour l'étude des réactions de captures radiatives induites sur le lithium
Le dispositif décrit consiste en un évaporateur de lithium et un « vobulateur de position de cible ». L'évaporateur nous permet de préparer in situ des cibles exemptes de contaminations. Le « vobulateur » fait décrire à la cible une courbe de Lissajous par rapport au faisceau afin d'éviter la surchauffe de la cible
DĂ©pouillement et analyse de spectres Ă l'aide d'un ordinateur IBM 1800
On décrit brièvement un système d'analyse de résultats d'expériences à basse énergie. Un dialogue utilisateur-ordinateur améliore fortement la rapidité et la facilité des analyses
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Spatially explicit ecological modeling improves empirical characterization of plant pathogen dispersal
Dispersal is a key ecological process, but it remains difficult to measure. By recording numbers of dispersed individuals at different distances from the source, one acquires a dispersal gradient. Dispersal gradients contain information on dispersal, but they are influenced by the spatial extent of the source. How can we separate the two contributions to extract knowledge about dispersal? One could use a small, point-like source for which a dispersal gradient represents a dispersal kernel, which quantifies the probability of an individual dispersal event from a source to a destination. However, the validity of this approximation cannot be established before conducting measurements. This represents a key challenge hindering progress in characterization of dispersal. To overcome it, we formulated a theory that incorporates the spatial extent of sources to estimate dispersal kernels from dispersal gradients. Using this theory, we re-analyzed published dispersal gradients for three major plant pathogens. We demonstrated that the three pathogens disperse over substantially shorter distances compared to conventional estimates. This method will allow the researchers to re-analyze a vast number of existing dispersal gradients to improve our knowledge about dispersal. The improved knowledge has potential to advance our understanding of species' range expansions and shifts, and inform management of weeds and diseases in crops
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