35 research outputs found
The one-loop six-dimensional hexagon integral with three massive corners
We compute the six-dimensional hexagon integral with three non-adjacent
external masses analytically. After a simple rescaling, it is given by a
function of six dual conformally invariant cross-ratios. The result can be
expressed as a sum of 24 terms involving only one basic function, which is a
simple linear combination of logarithms, dilogarithms, and trilogarithms of
uniform degree three transcendentality. Our method uses differential equations
to determine the symbol of the function, and an algorithm to reconstruct the
latter from its symbol. It is known that six-dimensional hexagon integrals are
closely related to scattering amplitudes in N=4 super Yang-Mills theory, and we
therefore expect our result to be helpful for understanding the structure of
scattering amplitudes in this theory, in particular at two loops.Comment: 15 pages, 2 figure
High Current, High frequency ECRIS development program for LHC heavy ion beam application
A research program with the aim of producing pulsed currents with hitherto unequalled intensity of Pb27+, with length and repetition ratecompatible with those desired by CERN (1 mAe / 400 ms / 10 Hz in the context of future heavy ion collisions at LHC) is organised in acollaboration between CERN/GSI/CEA-Grenoble and IN2P3-ISNG.Two main experimental programs will be carried out : (i) tests with the LNS-Catania team on the SERSE superconducting source with a 28 GHzgyrotron, (ii) tests on a non-superconducting source (new source at Grenoble) with a 28 GHz gyrotron. For this purpose CEA/DRFMC hasborrowed from CEA a 28 GHz - 10 kW gyrotron transmitter.The project includes also the construction of a source body, by ISNG, with conventional coils and permanent magnets for working at the frequencyof about 28 GHz and biased up to 60 kV. This source called PHOENIX will run on a test bench at ISN. PHOENIX is an improvement of thepresent ECR4-14.5 GHz/CERN source, having a mirror ratio R=2 at 14.5 GHz, and R=1.7 at 28 GHz (possibly reaching 2.1 T on the axis of thesource), and with a plasma volume up to 2.5 larger.Experiments at 28 GHz will be performed on the SERSE source in Catania at INFN/LNS where both the axial and the hexapolar fields will bevaried so that the mirror ratio is continuously varied up to R=1.6 ; the SERSE source will be also operated at lower magnetic fields such as thosewhich can be produced by conventional magnets (less than 2 T axial field at injection - far from the 28 GHz High-B mode)
Genetic variability of hepatitis C virus in chronically infected patients with viral breakthrough during interferon-ribavirin therapy.
Little is known about hepatitis C virus (HCV) breakthrough during antiviral therapy, although it would help in understanding HCV resistance to current antiviral treatments. To analyse the implication of virological factors and the vigour of humoral immune responses in this phenomenon, we studied nine chronic hepatitis C patients with a viral breakthrough during IFN/ribavirin combination therapy, as well as five responders and five non-responders. The IRES and regions coding for the capsid protein, the PePHD domain of envelope glycoprotein E2 and the NS5A and 5B proteins were amplified by RT-PCR before treatment, before and during breakthrough, and after treatment. The major variant sequence was obtained by direct sequencing. The heterogeneity of quasispecies was studied by SSCP in all patients and sequencing after cloning in seven genotype 1b-infected patients. Humoral responses against HCV epitopes were also analysed. The major sequences of IRES, PePHD, and NS5B remained stable during treatment, regardless of the treatment response. However, the capsid protein and the regions flanking PePHD showed sequence variations in breakthrough patients, although no specific mutation was identified. The variable V3 region of NS5A, but not the PKR-binding domain and the ISDR, seemed to be associated with differences in response to treatment. The analysis of HCV quasispecies revealed no characteristic pattern during treatment in breakthrough patients, whose HCV genome profiles looked most similar to that of non-responders. The humoral response was similar between groups. In conclusion, viral breakthrough does not seem to be due to selection of resistant strains with signature mutations
Strategic constraints and banking competitiveness in the light of the widening global market for financial services
SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : DO 2386 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Les systemes d'information et de communication sont-ils porteurs d'un nouveau modele d'organisation ?
Available at INIST (FR), Document Supply Service, under shelf-number : DO 2387 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc
Pouvoir et decision, politique et strategie
SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : DO 3626 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Analyse des organisations et entreprise : points de repere issus de la notion de pouvoir
Available at INIST (FR), Document Supply Service, under shelf-number : DO 3157 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc