50 research outputs found

    An Automated Emergency Airport and Off-Airport Landing Site Selector

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    We present a novel landing site selector capable of selecting suitable landing sites (airport and off-airport) for emergency landings. In a first step, information from several databases which includes, for instance, elevation data, is gathered by our system. Then, this information is processed in order to create a list of potential landing sites ranked according to several factors, such as the characteristics of the runway, the type of emergency or the current weather. A generic scenario and case studies have been defined in order to test the landing site selector, ultimately leading to a series of trajectories—generated with an emergency trajectory generator presented in previous publications—safely leading the aircraft to one of the landing sites chosen by our system.1The work presented in this paper has received funding from the Clean Sky 2 Joint Undertaking (JU) under grant agreement No 864771, corresponding to the SafeNcy project (https://cordis.europa.eu/project/id/864771). The JU receives support from the European Union’s Horizon 2020 research and innovation programme and the Clean Sky 2 JU members other than the Union. The opinions expressed herein reflect the authors view only. Under no circumstances shall the Clean Sky 2 JU be responsible for any use that may be made of the information contained herein.Peer ReviewedPostprint (author's final draft

    Bat responses to changes in forest composition and prey abundance depend on landscape matrix and stand structure

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    Despite the key importance of the landscape matrix for bats, we still not fully understand how the effect of forest composition interacts at combined stand and landscape scales to shape bat communities. In addition, we lack detailed knowledge on the effects of local habitat structure on bat-prey relationships in forested landscapes. We tested the assumptions that (i) forest composition has interacting effects on bats between stand and landscape scales; and (ii) stand structure mediates prey abundance effects on bat activity. Our results indicated that in conifer-dominated landscapes (> 80% of coniferous forests) bat activity was higher in stands with a higher proportion of deciduous trees while bats were less active in stands with a higher proportion of deciduous trees in mixed forest landscapes (~ 50% of deciduous forests). Moth abundance was selected in the best models for six among nine bat species. The positive effect of moth abundance on Barbastella barbastellus was mediated by vegetation clutter, with dense understory cover likely reducing prey accessibility. Altogether, our findings deepen our understanding of the ecological processes affecting bats in forest landscapes and strengthen the need to consider both landscape context and trophic linkage when assessing the effects of stand-scale compositional and structural attributes on bats

    Quantifier la réponse de la biodiversité à l'exploitation forestiÚre

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    Le projet Gestion forestiÚre, Naturalité et Biodiversité a pour but d'étudier le lien entre biodiversité, exploitation forestiÚre et naturalité en comparant des parcelles exploitées à des parcelles non-exploitées (Réserves Biologiques Intégrales ou parties intégrales de Réserves Naturelles). En partenariat avec l'ONF, RNF et l'INRA, nous travaillons depuis 2008 sur des réserves intégrales soustraites à l'exploitation depuis au moins 20 ans. L'étude repose sur l'échantillonnage de 7 groupes taxonomiques : plantes vasculaires, mousses, champignons, chauve-souris, oiseaux, coléoptÚres carabiques et saproxyliques

    CAGIRE: a wide-field NIR imager for the COLIBRI 1.3 meter robotic telescope

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    The use of high energy transients such as Gamma Ray Bursts (GRBs) as probes of the distant universe relies on the close collaboration between space and ground facilities. In this context, the Sino-French mission SVOM has been designed to combine a space and a ground segment and to make the most of their synergy. On the ground, the 1.3 meter robotic telescope COLIBRI, jointly developed by France and Mexico, will quickly point the sources detected by the space hard X-ray imager ECLAIRs, in order to detect and localise their visible/NIR counterpart and alert large telescopes in minutes. COLIBRI is equipped with two visible cameras, called DDRAGO-blue and DDRAGO-red, and an infrared camera, called CAGIRE, designed for the study of high redshift GRBs candidates. Being a low-noise NIR camera mounted at the focus of an alt-azimutal robotic telescope imposes specific requirements on CAGIRE. We describe here the main characteristics of the camera: its optical, mechanical and electronics architecture, the ALFA detector, and the operation of the camera on the telescope. The instrument description is completed by three sections presenting the calibration strategy, an image simulator incorporating known detector effects, and the automatic reduction software for the ramps acquired by the detector. This paper aims at providing an overview of the instrument before its installation on the telescope.Comment: Accepted by Experimental Astronom

    Forest management cessation and biodiversity: a synthesis of a nationwide French project

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    Extending the network of strict forest reserves is one of the conservation measures promoted by the French National Strategy for Biodiversity improvement. According to the scientific literature, strict forest reserves may help preserving a part of the biodiversity that is threatened by forestry. However, this strategy is based on poor knowledge in the temperate context and available studies may suffer from methodological shortcomings. The national-scale project named "Forest management, Naturalness and Biodiversity" aims at quantifying the effects on forest structure and biodiversity of management abandonment in strict reserves. Based on a meta-analysis of worldwide literature and original data from 213 study plots set up in 15 forest sites throughout France - around half of the plots in forests left unmanaged for from 8 to 148 years (mean: 46 years)- , we analyzed the response of 7 taxonomic groups to management abandonment. The meta-analysis demonstrates that forestry affects total richness of saproxylic taxa worldwide, which is verified in our national dataset. However, management abandonment per se is not always the best explanation of the differences between managed and unmanaged forests, but other variables, notably linked to deadwood, better explain the observed patterns for saproxylic groups. For other taxa, the response is weaker and depends more on structural features than on management abandonment. In terms of policy, our project has allowed methodological advances thanks to the development of inventory and remote sensing protocols, as well as statistical methods. The dataset we have gathered is also a first comparison of structure and biodiversity between strict forest reserves and managed forests for France. This network may therefore constitute a first basis for long term biodiversity monitoring in French forests

    GNB: Projet de recherche finalisĂ©e Ă  l’interface recherche-gestion et ses interactions avec BGF

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    La gestion durable des forĂȘts repose largement sur la biodiversitĂ© dont le fonctionnement reste cependant encore trĂšs insuffisamment connu. Il en dĂ©coule la nĂ©cessitĂ© d’amĂ©liorer, de maniĂšre gĂ©nĂ©rale, le socle de connaissances relatif Ă  la biodiversitĂ© et, plus particuliĂšrement, d’analyser les interactions entre changement climatique, productivitĂ© forestiĂšre et biodiversitĂ© en forĂȘt. Par ailleurs, les stratĂ©gies et dĂ©cisions des acteurs influent sur ces interactions et constituent Ă©galement des objets d’étude Ă  privilĂ©gier. C’est pourquoi le programme de recherche « BiodiversitĂ©, gestion forestiĂšre et politiques publiques » a lancĂ© en 2013 un appel Ă  projets de recherche avec deux entrĂ©es : - l’une par les sciences de la nature axĂ©e sur le changement climatique, les mesures de gestion et la dynamique de la biodiversitĂ© dans les Ă©cosystĂšmes ; - l’autre par les sciences humaines et sociales sur les stratĂ©gies et dĂ©cisions des acteurs, la gouvernance et les politiques publiques correspondant Ă  la premiĂšre entrĂ©e. Le prĂ©sent colloque a pour objectifs de : - prĂ©senter les rĂ©sultats des cinq projets de recherche qui ont Ă©tĂ© sĂ©lectionnĂ©s Ă  cette occasion sur chacune des deux entrĂ©es en les accompagnant en tant que de besoin de regards complĂ©mentaires et en illustrant l’un des projets par une visite sur le terrain ; - initier une rĂ©flexion sur le progrĂšs des connaissances dans ce domaine, en s’inspirant du devenir de projets antĂ©rieurs et en identifiant les principales lacunes Ă  combler. Il se dĂ©roulera en trois sessions, chacune introduite par des exposĂ©s d’une quinzaine de minutes et conclue par une table ronde permettant un dĂ©bat avec les participants et les invitĂ©s

    HARMONI at ELT: project status and instrument overview

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    International audienceHARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 450 nm to 2450 nm with resolving powers from 3500 to 18000 and spatial sampling from 60 mas to 4 mas. It can operate in two Adaptive Optics modes - SCAO (including a High Contrast capability) and LTAO - or with NOAO. The project is preparing for Final Design Reviews. HARMONI is a work-horse instrument that provides efficient, spatially resolved spectroscopy of extended objects or crowded fields of view. The gigantic leap in sensitivity and spatial resolution that HARMONI at the ELT will enable promises to transform the landscape in observational astrophysics in the coming decade. The project has undergone some key changes to the leadership and management structure over the last two years. We present the salient elements of the project restructuring, and modifications to the technical specifications. The instrument design is very mature in the lead up to the final design review. In this paper, we provide an overview of the instrument's capabilities, details of recent technical changes during the red flag period, and an update of sensitivities
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