1,857 research outputs found

    Calorimetry at the LHC

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    The Large Hadron Collider (LHC) is the new CERN accelerator that will provide proton proton collisions at s=\sqrt{s}=14~TeV. It will have two general purpose experiments: ATLAS and CMS, and two dedicated experiments: Alice, to study heavy ion collisions, and LHCb, to study b physics. The LHC is an explorative machine built to search for the Higgs boson and physics beyond the Standard Model. Calorimeters play a crucial role in these searches. In particular the electromagnetic calorimeter is fundamental in the search for the SM Higgs boson, depending on the mass range, either in the two photon decay channel or in the four leptons channel. Hadron calorimeters are important for super-symmetric particles searches where jets and missing transverse energy are expected. We present a review of the LHC experiments calorimeters and their expected performance

    Converging Strategies in Expression of Human Complex Retroviruses

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    The discovery of human retroviruses in the early 1980s revealed the existence of viral-encoded non-structural genes that were not evident in previously described animal retroviruses. Based on the absence or presence of these additional genes retroviruses were classified as ‘simple’ and ‘complex’, respectively. Expression of most of these extra genes is achieved through the generation of alternatively spliced mRNAs. The present review summarizes the genetic organization and expression strategies of human complex retroviruses and highlights the converging mechanisms controlling their life cycles

    Re-discovery of the top quark at the LHC and first measurements

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    This paper describes the top quark physics measurements that can be performed with the first LHC data in the ATLAS and CMS experiments.Comment: 6 pages, 2 figures. Talk given at `V Workshop Italiano sulla Fisica pp a LHC', Perugia, Italy, 30 January - 2 February 200

    Monte Carlo generators for top quark physics at the LHC

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    We review the main features of Monte Carlo generators for top quark phenomenology and present some results for t-tbar and single-top signals and backgrounds at the LHC.Comment: 7 pages, 5 figures. Talk given at `V Workshop Italiano sulla Fisica pp a LHC', Perugia, Italy, 30 January - 2 February 2008. References update

    Expression of alternatively spliced human T-cell leukemia virus type 1 mRNAs is influenced by mitosis and by a novel cis-acting regulatory sequence

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    Human T-cell leukemia virus type 1 (HTLV-1) expression depends on the concerted action of Tax, which drives transcription of the viral genome, and Rex, which favors expression of incompletely spliced mRNAs and determines a 2-phase temporal pattern of viral expression. In the present study, we investigated the Rex dependence of the complete set of alternatively spliced HTLV-1 mRNAs. Analyses of cells transfected with Rex-wild-type and Rex-knockout HTLV-1 molecular clones using splice site-specific quantitative reverse transcription (qRT)-PCR revealed that mRNAs encoding the p30Tof, p13, and p12/8 proteins were Rex dependent, while the p21rex mRNA was Rex independent. These findings provide a rational explanation for the intermediate-late temporal pattern of expression of the p30tof, p13, and p12/8 mRNAs described in previous studies. All the Rex-dependent mRNAs contained a 75-nucleotide intronic region that increased the nuclear retention and degradation of a reporter mRNA in the absence of other viral sequences. Selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) analysis revealed that this sequence formed a stable hairpin structure. Cell cycle synchronization experiments indicated that mitosis partially bypasses the requirement for Rex to export Rex-dependent HTLV-1 transcripts. These findings indicate a link between the cycling properties of the host cell and the temporal pattern of viral expression/latency that might influence the ability of the virus to spread and evade the immune system
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