First Evidence of a HIV-1 M/O Recombinant Form Circulating Outside Cameroon

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Collective character of spin excitations in a system of Mn2+^{2+} spins coupled to a two-dimensional electron gas

We have studied the low energy spin excitations in n-type CdMnTe based dilute magnetic semiconductor quantum wells. For magnetic fields for which the energies for the excitation of free carriers and Mn spins are almost identical an anomalously large Knight shift is observed. Our findings suggests the existence of a magnetic field induced ferromagnetic order in these structures, which is in agreement with recent theoretical predictions [J. K{\"o}nig and A. H. MacDonald, submitted Phys. Rev. Lett. (2002)]Comment: 4 figure

Radio emission of extensive air shower at CODALEMA: Polarization of the radio emission along the v*B vector

Cosmic rays extensive air showers (EAS) are associated with transient radio emission, which could provide an efficient new detection method of high energy cosmic rays, combining a calorimetric measurement with a high duty cycle. The CODALEMA experiment, installed at the Radio Observatory in Nancay, France, is investigating this phenomenon in the 10^17 eV region. One challenging point is the understanding of the radio emission mechanism. A first observation indicating a linear relation between the electric field produced and the cross product of the shower axis with the geomagnetic field direction has been presented (B. Revenu, this conference). We will present here other strong evidences for this linear relationship, and some hints on its physical origin.Comment: Contribution to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009. 4 pages, 8 figures. v2: Typo fixed, arxiv references adde

Enzymatically-synthesized xylo-oligosaccharides laurate esters as surfactants of interest

Lipase-catalyzed synthesis of xylo-oligosaccharides esters from pure xylobiose, xylotriose and xylotetraose in the presence of vinyl laurate was investigated. The influence of different experimental parameters such as the loading of lipase, the reaction duration or the use of a co-solvent was studied and the reaction conditions were optimized with xylobiose. Under the best conditions, a regioselective esterification occurred to yield a monoester with the acyl chain at the OH-4 of the xylose unit at the non-reducing end. Surface-active properties of these pure xylo-oligosaccharides fatty esters have been evaluated. They display interesting surfactant activities that differ according to the degree of polymerization (DP) of the glycone moiety. © 202

Utilisation du Raltegravir chez des patients infectés par HIV-1 group O

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Geomagnetic origin of the radio emission from cosmic ray induced air showers observed by CODALEMA

The new setup of the CODALEMA experiment installed at the Radio Observatory in Nancay, France, is described. It includes broadband active dipole antennas and an extended and upgraded particle detector array. The latter gives access to the air shower energy, allowing us to compute the efficiency of the radio array as a function of energy. We also observe a large asymmetry in counting rates between showers coming from the North and the South in spite of the symmetry of the detector. The observed asymmetry can be interpreted as a signature of the geomagnetic origin of the air shower radio emission. A simple linear dependence of the electric field with respect to vxB is used which reproduces the angular dependencies of the number of radio events and their electric polarity.Comment: 9 pages, 15 figures, 1 tabl