Hoverflies are often used as bio-indicators for ecosystem conservation, but only few studies have actually investigated the key factors explaining their richness in woodlands. In a fragmented landscape in southwest France, we investigated the joint effects of woodland area, structural heterogeneity, connectivity and history on the species richness of… (More)
We have studied the magnetic cluster compound Nb 6 F 15 which has an odd number of 15 valence electrons per (Nb 6 F 12) 3? cluster core, as a function of temperature using nuclear magnetic resonance, magnetic susceptibility, electron magnetic resonance and neutron powder diffraction. Nuclear magnetic resonance of the 19 F nuclei shows two lines… (More)
This paper deals with the numerical analysis of the focalization of a beam of particles. In particular, this model can be useful to check whether or not the cutoff Boltzmann equation leads to some kind of smoothing effect as for the Fokker-Planck-Landau equation.