A compact and versatile dynamic flow cryostat for photon science

We have developed a helium gas flow cryostat for use on synchrotron tender to hard X-ray beamlines. Very efficient sample cooling is achieved because the sample is placed directly in the cooling helium flow on a removable sample holder. The cryostat is compact and easy to operate; samples can be changed in less than 5 min at any temperature. The cryostat has a temperature range of 2.5-325 K with temperature stability better than 0.1 K. The very wide optical angle and the ability to operate in any orientation mean that the cryostat can easily be adapted for different X-ray techniques. It is already in use on different beamlines at the European Synchrotron Radiation Facility (ESRF), ALBA Synchrotron Light Facility (ALBA), and Diamond Light Source (DLS) for inelastic X-ray scattering, powder diffraction, and X-ray absorption spectroscopy. Results obtained at these beamlines are presented here

High long-term survival and asymmetric movements in a reintroduced metapopulation of Cinereous vultures

International audiencePost-release mortality and movements are top proximate factors of translocation failure. Yet, survival and movement reflect different demographic and behavioral processes and may therefore have contrasted responses to management, although they are often very difficult to disentangle in animal populations. To provide guidance in animal translocations, we discriminated the respective roles of survival and movement in the long-term dynamic of a translocated metapopulation of cinereous vultures (Aegypius monachus) in France using multi-event capture-recapture analyses of reintroduced (n=119) and wild-born individuals (n=163) observations. Annual apparent survival rates were high and structured in age (>0.8 for young and >0.9 for adults) and did not differ between individuals origin (wild-born or released), release methods (aviary or hacking) nor between regions (Alps and Causses), except for those released in the Alps experiencing a reduced survival for one year after release. In contrast, age structure movements differed between populations and origin status. Wild-born young from the Causses were more erratic than those from the Alps and older individuals, whereas vultures reintroduced in the Causses demonstrated restricted movements during their first year after release. Despite such asymmetric movements, we overall highlight a strong tropism of individuals whatever the region and their origin. Since movement and survival were respectively higher and lower in young compared to adults, we recommend to first release adults in the primary stage of metapopulation translocations for increasing the establishment success at the release site. Further releasing young and securing successful breeding into the wild would increase demographic growth and between population connections

Appendix A. Selection of the best tag loss and dispersal models in each site.

Selection of the best tag loss and dispersal models in each site

Resonant inelastic X-ray scattering of magnetic excitations under pressure

International audienceResonant inelastic x-ray scattering (RIXS) is an extremely valuable tool for the study of elementary, including magnetic, excitations in matter. Latest developments of this technique mostly aimed at improving the energy resolution and performing polarization analysis of the scattered radiation, with a great impact on the interpretation and applicability of RIXS. Instead, this article focuses on the sample environment and presents a setup for high-pressure low-temperature RIXS measurements of low-energy excitations. The feasibility of these experiments is proved by probing the magnetic excitations of the bilayer iridate Sr$_3$Ir$_2$O$_7$ at pressures up to 12 GPa