104 research outputs found

    Picosecond polarized supercontinuum generation controlled by intermodal four-wave mixing for fluorescence lifetime imaging microscopy

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    International audienceWe present the generation of a picosecond polarized supercontinuum in highly birefringent multimodal microstructured fiber. The initial steps of the spectral broadening are dominated by intermodal four-wave mixing controlled by the specific fiber design. Using a low repetition rate ultra-stable solid state laser, a pulse train well-suited for versatile time-domain fluorescence lifetime imaging applications is obtaine

    Visible supercontinuum generation controlled by intermodal four-wave mixing in micro-structured fibre

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    International audienceWe present an experimental and numerical study of supercontinuum generation extended in the visible part of the spectrum by using a selective optical coupling of the pump wave in the largely anomalous dispersion regime. The broadband frequency generation is induced by an initial four-wave mixing process that converts the pump wave at 1064 nm into 831 nm anti-Stokes and 1478 nm Stokes wavelengths. Phase matching is ensured on such a large frequency shift thanks to a microstructured multimodal fiber with a specific design. Continuum generation is therefore enhanced around the two generated sideband

    The GenTree Platform: growth traits and tree-level environmental data in 12 European forest tree species

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    Background: Progress in the field of evolutionary forest ecology has been hampered by the huge challenge of phenotyping trees across their ranges in their natural environments, and the limitation in high-resolution environmental information. Findings: The GenTree Platform contains phenotypic and environmental data from 4,959 trees from 12 ecologically and economically important European forest tree species: Abies alba Mill. (silver fir), Betula pendula Roth. (silver birch), Fagus sylvatica L. (European beech), Picea abies (L.) H. Karst (Norway spruce), Pinus cembra L. (Swiss stone pine), Pinus halepensis Mill. (Aleppo pine), Pinus nigra Arnold (European black pine), Pinus pinaster Aiton (maritime pine), Pinus sylvestris L. (Scots pine), Populus nigra L. (European black poplar), Taxus baccata L. (English yew), and Quercus petraea (Matt.) Liebl. (sessile oak). Phenotypic (height, diameter at breast height, crown size, bark thickness, biomass, straightness, forking, branch angle, fructification), regeneration, environmental in situ measurements (soil depth, vegetation cover, competition indices), and environmental modeling data extracted by using bilinear interpolation accounting for surrounding conditions of each tree (precipitation, temperature, insolation, drought indices) were obtained from trees in 194 sites covering the species’ geographic ranges and reflecting local environmental gradients. Conclusion: The GenTree Platform is a new resource for investigating ecological and evolutionary processes in forest trees. The coherent phenotyping and environmental characterization across 12 species in their European ranges allow for a wide range of analyses from forest ecologists, conservationists, and macro-ecologists. Also, the data here presented can be linked to the GenTree Dendroecological collection, the GenTree Leaf Trait collection, and the GenTree Genomic collection presented elsewhere, which together build the largest evolutionary forest ecology data collection available

    Between but not within species variation in the distribution of fitness effects

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    New mutations provide the raw material for evolution and adaptation. The distribution of fitness effects (DFE) describes the spectrum of effects of new mutations that can occur along a genome, and is therefore of vital interest in evolutionary biology. Recent work has uncovered striking similarities in the DFE between closely related species, prompting us to ask whether there is variation in the DFE among populations of the same species, or among species with different degrees of divergence, i.e., whether there is variation in the DFE at different levels of evolution. Using exome capture data from six tree species sampled across Europe we characterised the DFE for multiple species, and for each species, multiple populations, and investigated the factors potentially influencing the DFE, such as demography, population divergence and genetic background. We find statistical support for there being variation in the DFE at the species level, even among relatively closely related species. However, we find very little difference at the population level, suggesting that differences in the DFE are primarily driven by deep features of species biology, and that evolutionarily recent events, such as demographic changes and local adaptation, have little impact

    Les grands arrĂȘts du petit droit

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    La (décevante) réforme du droit des relations commerciales

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    L’éthique du sport : le point de vue du juriste

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    Mesdames, Messieurs, Chers CollĂšgues, Chers amis, Je suis, Ă  la fois, heureux et inquiet de vous prĂ©senter cette communication qui est censĂ©e exprimer le “point de vue du juriste”. Heureux, car le thĂšme de cette journĂ©e est tout Ă  fait passionnant ; qu’il me soit d’ailleurs permis de remercier chaleureusement les organisateurs pour leur invitation. Inquiet, aussi, car mon rapport prend, en ce dĂ©but de journĂ©e, les allures d’un rapport introductif ; or je ne suis pas sĂ»r d’ĂȘtre capable de mett..

    Les intermédiaires sportifs

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    Comment faire pour gagner 100 millions de dollars sur une annĂ©e et en toute lĂ©galité ? RĂ©ponse : ĂȘtre agent de football, puisque c’est la somme qui a Ă©tĂ©, en 2017, perçue sous forme de commissions par un certain Constantin Dumitrascu. Cette entame est aguicheuse, bien Ă©videmment, puisque tous les agents sportifs ne gravitent pas dans de telles sphĂšres. Ce serait aussi faux que de croire que tous les joueurs de football perçoivent les 30 millions d’euros de salaires annuels que Ronaldo a obten..

    Oui au contrĂŽle judiciaire du prix !

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