240 research outputs found
Species for a national coherence of the French Green and Blue Infrastructure (TVB program): how have they been taken into account in the Regional Ecological-Continuity Plans (SRCE)?
La « Trame verte et bleue » est une politique publique portĂ©e en France par le MinistĂšre de lâenvironnement qui vise Ă mieux prendre en compte la biodiversitĂ© dans lâamĂ©nagement du territoire et en particulier Ă rĂ©duire la fragmentation des habitats. Son objectif est de prĂ©server et restaurer un rĂ©seau Ă©cologique, constituĂ© de rĂ©servoirs et de corridors qui les relient. Pour cela, elle est mise en Ćuvre Ă plusieurs Ă©chelles territoriales. Au niveau national, un document-cadre (les ON TVB) fixe les grands objectifs de la politique. Les ON TVB comprennent notamment une liste dâespĂšces sĂ©lectionnĂ©es dans les rĂ©gions qui ont pour elles une « responsabilitĂ© nationale » en termes de populations hĂ©bergĂ©es. Ces espĂšces Ă©taient Ă prendre en compte (notion dâopposabilitĂ© juridique) par les schĂ©mas rĂ©gionaux de la politique TVB (les SRCE). Alors que la phase dâĂ©laboration des SRCE est dĂ©sormais terminĂ©e, un bilan de ce dispositif a Ă©tĂ© effectuĂ© pour analyser comment cette prise en compte sâest traduite dans les SRCE sur un plan scientifique et technique. Dans ce travail, deux modalitĂ©s de prise en compte ont prĂ©alablement Ă©tĂ© posĂ©es pour dresser ce bilan : i) lâutilisation de ces espĂšces pour identifier la trame rĂ©gionale et ii) la vĂ©rification a posteriori de la prĂ©sence de ces espĂšces dans la trame rĂ©gionale. Les rĂ©sultats montrent que les deux tiers des rĂ©gions se retrouvent dans lâune ou lâautre de ces deux mĂ©thodes. PrĂšs de la moitiĂ© des rĂ©gions ont justifiĂ© leur prise en compte par une utilisation de ces espĂšces pour lâidentification de leurs rĂ©servoirs et corridors. Environ un tiers des rĂ©gions a adoptĂ© une approche a posteriori en vĂ©rifiant la proportion de la rĂ©partition des espĂšces qui se retrouve dans la trame rĂ©gionale. Dans une logique dâĂ©valuation de la politique TVB, il serait utile dâapprofondir ce premier bilan basĂ© sur une analyse documentaire des SRCE, par une Ă©valuation extĂ©rieure afin de vĂ©rifier si la prĂ©servation de ces enjeux espĂšces est effective et suffisante, dâun point de vue Ă©cologique. Aussi, au regard du bilan dressĂ©, il est dâores et dĂ©jĂ possible de prĂ©coniser une clarification des ON TVB concernant les attentes en matiĂšre de prise en compte des espĂšces. Ce renforcement des ON TVB est dâautant plus nĂ©cessaire dans le contexte actuel dâintĂ©gration des SRCE dans un nouveau schĂ©ma rĂ©gional intĂ©grateur (le Sraddet).The âTrame verte et bleueâ (TVB) is a French public policy that aims to better include biodiversity in territorial planning and particularly to reduce habitat fragmentation. The overall objective is to preserve and restore an ecological network, consisting of biodiversity cores and corridors linking them. For that purpose, TVB policy is deployed on several territorial levels. On the national level, a framework document (titled ON-TVB) presents the main objectives of the program. In particular, the ON-TVB lists some animal species for each French regions that have a national responsibility to protect them. The French regions had to take into account (within the meaning of legal enforceability) those TVB species within their regional schemes (named SRCE). Now that SRCE are adopted, it is time to have an overview of this new and original system and to evaluate its efficacity and effectivity from a technical and scientific point of view. In this work, two methods to take into account the TVB species have been identified to make this assessment: i) using the TVB species to design the regional ecological network or ii) checking retrospectively that the TVB species are actually present in the regional ecological network. The results show that two-thirds of the French regions used one of those two methods. About half of the French regions took into account the TVB species using them to design their cores and corridors. Almost one third of the French regions checked the proportion of the TVB species distribution found in their regional ecological network. Yet, to look forward this first analysis based on SRCE review, an independent assessment is needed to verify that the TVB species were sufficiently taken into account. As for now, in view of those results, itâs already possible to suggest that the ON-TVB better clarify what âto take into accountâ means and what is expected of the regions about the TVB species. Such a consolidation of the ON-TVB is all the more necessary in the current context in which SRCE are being integrated with other regional plans into a new inclusive regional scheme (named âSraddetâ)
Highly Photoactive Polythiophenes Obtained by Electrochemical Synthesis from Bipyridine-Containing Terthiophenes
According to numerous previous reports, a Z-scheme with two photon absorbers is the most promising strategy to achieve artificial photosynthesis, but in addition to two efficient catalysts â one for oxygen evolution, the other for CO2 reduction â two different and complementary semiconducting sensitizers are required. Here we present the synthesis of two bipyridine-functionalized terthiophenes, which can be electropolymerized to give photoactive p-type semiconductors the capability to perform as photocathode in photoelectrochemical cells for water photosplitting or artificial photosynthesis. Indeed the bipyridine moiety in their structure allows the binding of transition metal carbonyl complexes employed in CO2 reduction, and their band-gap is suitable for the coupling with wide band-gap semiconductors, which have already found application as photoanodes. Finally, they are characterized by photogenerated charge carrier density between 1.1 and 1.4 Ă 1019 cmâ3, with first-order recombination constant of 0.7â1.8 Ă 10â2 sâ1. These figures are of the same order of magnitude of their inorganic counterparts and would therefore guarantee photoconductivity of the device and the activation of the organometallic catalysts with which they should be coupled to function as photocathodes for CO2 reduction
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