Time resolved observation of multiple electronic configurations in the electronic relaxation of isolated molecules by photoelectron imaging

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Closed Timelike Curves and Holography in Compact Plane Waves

We discuss plane wave backgrounds of string theory and their relation to Goedel-like universes. This involves a twisted compactification along the direction of propagation of the wave, which induces closed timelike curves. We show, however, that no such curves are geodesic. The particle geodesics and the preferred holographic screens we find are qualitatively different from those in the Goedel-like universes. Of the two types of preferred screen, only one is suited to dimensional reduction and/or T-duality, and this provides a ``holographic protection'' of chronology. The other type of screen, relevant to an observer localized in all directions, is constructed both for the compact and non-compact plane waves, a result of possible independent interest. We comment on the consistency of field theory in such spaces, in which there are closed timelike (and null) curves but no closed timelike (or null) geodesics.Comment: 21 pages, 3 figures, LaTe

Gravitational Lensing by Black Holes

We review the theoretical aspects of gravitational lensing by black holes, and discuss the perspectives for realistic observations. We will first treat lensing by spherically symmetric black holes, in which the formation of infinite sequences of higher order images emerges in the clearest way. We will then consider the effects of the spin of the black hole, with the formation of giant higher order caustics and multiple images. Finally, we will consider the perspectives for observations of black hole lensing, from the detection of secondary images of stellar sources and spots on the accretion disk to the interpretation of iron K-lines and direct imaging of the shadow of the black hole.Comment: Invited article for the GRG special issue on lensing (P. Jetzer, Y. Mellier and V. Perlick Eds.). 31 pages, 12 figure

Desaturations microsomales hepatiques chez la ratte allaitante ingerant un regime hypoproteique supplemente ou non en methionine

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Multifragmentation of the Au(H2O)n10+ Cluster Ions by Collision with Helium

International audienceA beam of mass selected Au(H2O)n+ (n = 1-10) cluster ions has been generated using a source that couples laser evaporation, supersonic expansion, and tandem time-of-flight mass spectrometry. A collision-induced-dissociation (CID) experiment has been performed with helium at energies in the range of 0.2-3 eV. A maximum of four water molecules is lost by the clusters. The key point is the data analysis where the total (loss of at least one water molecule) and partial (loss of a specified number of water molecules) CID cross sections have been simulated using a model describing the energy transfer between helium and the cluster. This has allowed us to fit the experimental data and to give insight into the structure and energetic of the Au(H2O)n+ clusters, unraveling the existence of two kinds of isomers for these clusters, one with two water molecules coordinating the metal ion, tentatively assigned to (H2O)p(H2O)Au+(H2O)(H2O)n-p-2, and a more compact one with three (or more) coordinating water molecules. Multifragmentation of Au(H2O)n6+ clusters seems to involve a competition between the sequential loss of several water molecules and the loss of a water dimer and possibly a trimer

Experimental Evidence for Ultrafast Electronic Relaxation in Molecules, Mediated by Diffuse States

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Effects of protein level, methionine supplementation and carbohydrate type of the diet on liver lipid and plasma free threonine contents in the lactating rat

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