2,938 research outputs found
La tournée du Président George W. Bush en Amérique latine du 8 au 14 mars 2007
En mars dernier, en l’espace d’à peine six jours, le président des États-Unis a effectué une tournée attendue et remarquée qui l’a conduit dans cinq pays des Amériques : le Brésil, l’Uruguay, la Colombie, le Guatemala et le Mexique. Pour cerner les enjeux de cette visite, cas par cas, l’Observatoire des Amériques a fait appel à quatre collaborateurs dont les contributions ont servi à préparer la présente chronique
A scalar field condensation instability of rotating anti-de Sitter black holes
Near-extreme Reissner-Nordstrom-anti-de Sitter black holes are unstable
against the condensation of an uncharged scalar field with mass close to the
Breitenlohner-Freedman bound. It is shown that a similar instability afflicts
near-extreme large rotating AdS black holes, and near-extreme hyperbolic
Schwarzschild-AdS black holes. The resulting nonlinear hairy black hole
solutions are determined numerically. Some stability results for (possibly
charged) scalar fields in black hole backgrounds are proved. For most of the
extreme black holes we consider, these demonstrate stability if the ``effective
mass" respects the near-horizon BF bound. Small spherical
Reissner-Nordstrom-AdS black holes are an interesting exception to this result.Comment: 34 pages; 13 figure
Definition of a collaborative working model to the logistics area using design for Six Sigma
Purpose - The purpose of this paper is to create an online enterprise community for all logistics employees of Bosch Car Multimedia division in the Bosch Group, for an internal collaboration of the entire Bosch Group based on an IBM Connections platform: Bosch Connect. An additional concern, collected throughout the project, was to bring employees to join the platform, making it a tool of your daily work. The final objective is to implement and promote a tool to foster internal and external integration of the Bosch logistics community.Design/methodology/approach - A case study is presented to illustrate the use of a Design for Six Sigma (DFSS) methodology to support all the process creation of a collaborative community. There are several variants of the methodology DFSS. For the context of this project, will be used the define, measure, analyze, design and verify (DMADV) methodology, that is appropriated to design services processes and it addresses specifically to the remodeling processes.Findings - The use of DMADV methodology allows establish, systematically, a model which was in accordance with the target population needs.Research limitations/implications - Since this is a case study, it is not possible to generalize the results. Furthermore, this project was developed in a limit time (about four months). Thus, was not possible to obtain a large community.Practical implications - The case study brings some evidence of how a systematic approach to the design of a online enterprise community can support designers to meet user's needs.Social implications - A new approach is proposed to meet an online enterprise community user's needs.Originality/value - To the best of the authors' knowledge, there is no evidence the use of this methodology to support a construction of an online enterprise community.info:eu-repo/semantics/publishedVersio
p-wave Holographic Superconductors and five-dimensional gauged Supergravity
We explore five-dimensional and
SO(6) gauged supergravities as frameworks for condensed matter applications.
These theories contain charged (dilatonic) black holes and 2-forms which have
non-trivial quantum numbers with respect to U(1) subgroups of SO(6). A question
of interest is whether they also contain black holes with two-form hair with
the required asymptotic to give rise to holographic superconductivity. We first
consider the case, which contains a complex two-form potential
which has U(1) charge . We find that a slight
generalization, where the two-form potential has an arbitrary charge , leads
to a five-dimensional model that exhibits second-order superconducting
transitions of p-wave type where the role of order parameter is played by
, provided . We identify the operator that condenses
in the dual CFT, which is closely related to Super Yang-Mills
theory with chemical potentials. Similar phase transitions between R-charged
black holes and black holes with 2-form hair are found in a generalized version
of the gauged supergravity Lagrangian where the two-forms have
charge .Comment: 35 pages, 14 figure
Tetrahydropyrazolo[1,5-a]Pyrimidine-3-Carboxamide and N-Benzyl-6′,7′-Dihydrospiro[Piperidine-4,4′-Thieno[3,2-c]Pyran] analogues with bactericidal efficacy against Mycobacterium tuberculosis targeting MmpL3
Mycobacterium tuberculosis is a major human pathogen and the causative agent for the pulmonary disease, tuberculosis (TB). Current treatment programs to combat TB are under threat due to the emergence of multi-drug and extensively-drug resistant TB. As part of our efforts towards the discovery of new anti-tubercular leads, a number of potent tetrahydropyrazolo[1,5-a]pyrimidine-3-carboxamide(THPP) and N-benzyl-6′,7′-dihydrospiro[piperidine-4,4′-thieno[3,2-c]pyran](Spiro) analogues were recently identified against Mycobacterium tuberculosis and Mycobacterium bovis BCG through a high-throughput whole-cell screening campaign. Herein, we describe the attractive in vitro and in vivo anti-tubercular profiles of both lead series. The generation of M. tuberculosis spontaneous mutants and subsequent whole genome sequencing of several resistant mutants identified single mutations in the essential mmpL3 gene. This ‘genetic phenotype’ was further confirmed by a ‘chemical phenotype’, whereby M. bovis BCG treated with both the THPP and Spiro series resulted in the accumulation of trehalose monomycolate. In vivo efficacy evaluation of two optimized THPP and Spiro leads showed how the compounds were able to reduce >2 logs bacterial cfu counts in the lungs of infected mice
Kerr-AdS and its Near-horizon Geometry: Perturbations and the Kerr/CFT Correspondence
We investigate linear perturbations of spin-s fields in the Kerr-AdS black
hole and in its near-horizon geometry (NHEK-AdS), using the Teukolsky master
equation and the Hertz potential. In the NHEK-AdS geometry we solve the
associated angular equation numerically and the radial equation exactly. Having
these explicit solutions at hand, we search for linear mode instabilities. We
do not find any (non-)axisymmetric instabilities with outgoing boundary
conditions. This is in agreement with a recent conjecture relating the
linearized stability properties of the full geometry with those of its
near-horizon geometry. Moreover, we find that the asymptotic behaviour of the
metric perturbations in NHEK-AdS violates the fall-off conditions imposed in
the formulation of the Kerr/CFT correspondence (the only exception being the
axisymmetric sector of perturbations).Comment: 26 pages. 4 figures. v2: references added. matches published versio
Deductive Verification of Cryptographic Software
We report on the application of an off-the-shelf verification platform to the RC4 stream cipher cryptographic software implementation (as available in the openSSL library), and introduce a deductive verification technique based on self-composition for proving the absence of error propagation
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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