Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA

L'ancrage écologique dans les filières animales relocalisées : analyse comparative d'initiatives en France, au Maroc et au Sénégal

International audienceThis paper aims at analyzing the ecological embeddedness (EE) of localized animal and food systems. We compare five initiatives in France, Morocco and Senegal which aim at differentiating their origin. This analysis shows three different levels of EE and confirms the ecological heterogeneity of these food systems

Fischer–Tropsch Synthesis Over Zr-Promoted Co/γ-Al2O3 Catalysts

Two Zr-modified alumina supports were synthetized containing the same amount of Zr but a different distribution of this modifier over the alumina surface. These supports, together with the unmodified alumina carrier, were used to prepare three cobalt-based catalysts which were characterized and tested under relevant Fischer–Tropsch conditions. The three catalysts presented very similar porosity and cobalt dispersion. The addition of Zr nor its distribution enhanced the catalyst reducibility. The catalyst activity was superior when using a carrier consisting of large ZrO2 islands over the alumina surface. The use of a carrier with a homogeneous Zr distribution had however, a detrimental effect. Moreover, a faster initial deactivation rate was observed for the Zr-promoted catalysts, fact that may explain this contradictory effect of Zr on activity. Finally, the addition of Zr showed a clear enhancement of the selectivity to long chain hydrocarbons and ethylene, especially when Zr was well dispersed.Ministerio de Economía y Competitividad—MINECO (BES-2013-062806, ENE2013-47880- C3-2-R and ENE2015-66975-C3-2-R) co-financed by FEDER funds from the European UnionEuropean Union Seventh Framework Programme (FP7/2013) under Grant Agreement No. 30873