High-frequency directivity effects: evidence from analysis of the Les Saintes records

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Highly efficient synthesis of the tricyclic core of Taxol by cascade metathesis

An efficient enantioselective synthesis of the ABC tricyclic core of the anticancer drug Taxol is reported. The key step of this synthesis is a cascade metathesis reaction, which leads in one operation to the required tricycle if appropriate fine-tuning of the dienyne precursor is performed

: De l'échelle d'un réseau instrumental régional à celle de déploiements temporaires locaux

International audienceConstruire des catalogues d'informations sismologiques des plus complets représente un enjeu majeur en sismologie. L'implémentation régulière d'instruments sur le territoire national et l'accroissement massif de la quantité de données qui y est associée rend cependant difficile le traitement et l'analyse exhaustif des données obtenues. Depuis peu des techniques d'apprentissage machine sont développées par la communauté scientifique pour aider à l'automatisation du traitement de la donnée et palier à ce problème. Parmi ces méthodes, PhaseNet, un algorithme de détection et pointé des phases sismiques régionales basé sur les réseaux de neurones convolutifs, semble particulièrement efficace. Nous présentons ici une analyse des performances et de l'apport potentiel de cet algorithme dans différents cas de figures, de l'utilisation dans le cas d'une antenne sismique temporaire à faible ouverture géométrique (10km2) à celle d'un réseau permanent régional (105 km2), en passant par des installations temporaires en réseaux denses (103 km2), et en intégrants plusieurs types de capteurs

Data visualization for vegetal landscapes: Building 3D representations of organ biomass compartments: How plant production could constrain 3D lollypop-like representations

International audienc

Data visualization for vegetal landscapes: Building 3D representations of organ biomass compartments: How plant production could constrain 3D lollypop-like representations

International audienceIn the past decade, with the power of graphical boards, visualization of virtual natural scene become popular in multimedia applications. It usually relies on degraded virtual single plant geometrical representations and massive use of textures. Such scenes show however poor variability in terms of the number of species and individual plasticity. They also show strong animation constraints, many limited to viewpoint moves, ignoring growth processes. We propose here a frame for future works related to virtual plant visualization. It aims to drop down the classical geometrical descriptions of individual plants for the benefits of functional representations, aggregated up to a single crown. We then show that a wide range of parametric virtual crown shapes can be built from the knowledge of leaf area. Moreover, production outputs computed at each simulation time step by crop models or FSPM models define strong constraints in the organ positioning. Such constraints can be used to build hierarchical virtual geometries underlying the plant main axis and its crown decomposition according to its axis typology. Conversely, similar representations can also be generated from an exhaustive representation of virtual or real trees. On such plants, we first build a point cloud from the organ 3D coordinates. A statistical hierarchical dynamic clustering analysis can then be applied to the leaf cloud. It allows obtaining the statistical ellipsoid decomposition that can then be used for comparisons or shape fitting optimization. We finally introduce some technical elements showing that basic 3D shapes used for functional visualization (cone frustum and ellipsoids) can be fully generated and rendered by GPU techniques. As a summary, simulated plant functional visualization appears as a promising research track, freeing models from complex and costly geometrical computations. These representations also propose a new frame of discussions on tree crown modeling and descriptions for diagnosis purposes