2,004 research outputs found

    Study of high-pT charged particle suppression in PbPb compared to pp collisions at sqrt(sNN)=2.76 TeV.

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    The transverse momentum spectra of charged particles have been measured in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV by the CMS experiment at the LHC. In the transverse momentum range pt = 5-10 GeV/c, the charged particle yield in the most central PbPb collisions is suppressed by up to a factor of 5 compared to the pp yield scaled by the number of incoherent nucleon-nucleon collisions. At higher pt, this suppression is significantly reduced, approaching roughly a factor of 2 for particles with pt in the range pt=40-100 GeV/c

    ZASP Interacts with the Mechanosensing Protein Ankrd2 and p53 in the Signalling Network of Striated Muscle

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    ZASP is a cytoskeletal PDZ-LIM protein predominantly expressed in striated muscle. It forms multiprotein complexes and plays a pivotal role in the structural integrity of sarcomeres. Mutations in the ZASP protein are associated with myofibrillar myopathy, left ventricular non-compaction and dilated cardiomyopathy. The ablation of its murine homologue Cypher results in neonatal lethality. ZASP has several alternatively spliced isoforms, in this paper we clarify the nomenclature of its human isoforms as well as their dynamics and expression pattern in striated muscle. Interaction is demonstrated between ZASP and two new binding partners both of which have roles in signalling, regulation of gene expression and muscle differentiation; the mechanosensing protein Ankrd2 and the tumour suppressor protein p53. These proteins and ZASP form a triple complex that appears to facilitate poly-SUMOylation of p53. We also show the importance of two of its functional domains, the ZM-motif and the PDZ domain. The PDZ domain can bind directly to both Ankrd2 and p53 indicating that there is no competition between it and p53 for the same binding site on Ankrd2. However there is competition for this binding site between p53 and a region of the ZASP protein lacking the PDZ domain, but containing the ZM-motif. ZASP is negative regulator of p53 in transactivation experiments with the p53-responsive promoters, MDM2 and BAX. Mutations in the ZASP ZM-motif induce modification in protein turnover. In fact, two mutants, A165V and A171T, were not able to bind Ankrd2 and bound only poorly to alpha-actinin2. This is important since the A165V mutation is responsible for zaspopathy, a well characterized autosomal dominant distal myopathy. Although the mechanism by which this mutant causes disease is still unknown, this is the first indication of how a ZASP disease associated mutant protein differs from that of the wild type ZASP protein

    Recent results and developments on double-gap RPCs for CMS

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    Abstract A 3 mm wide-gap Resistive Plate Chamber, as proposed for CMS, has been tested in the H2 Cern beam line. Results on efficiency, rate capability, time resolution and cluster size are reported

    Resistive Plate Chambers in avalanche mode: a comparison between model predictions and experimental results

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    Abstract In this paper a model simulating the main aspects of avalanche growth and signal development in Resistive Plate Chambers (RPCs) is presented. The model has been used to compute the performances, in particular, charge distribution and efficiency of single- double- and multi-gap RPCs, and to compare them with the available experimental results. This model could be used to optimize the characteristics of this type of detector with a view to its use in the future large experiments at LHC: ATLAS and CMS

    The RPC system for the CMS experiment at the LHC

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    The CMS detector at the LHC has a redundant muon system. Two independent muon systems are used in the L1 trigger. One of them is based on wire chambers, the other on RPC detectors. Properly combining the answers of the two systems results in a highly efficient L1 trigger with high flexibility from the point of view of rate control. Simulation results show, however, that the RPC system suffers from false triggers caused by coincidence of spurious hits. System improvements, which could avoid oiling the chambers, are possible. RPCs have also proved to be very useful for muon track reconstruction

    Neutron irradiation of RPCs for the CMS experiment

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    All the CMS muon stations will be equipped with Resistive Plate Chambers (RPCs). They will be exposed to high neutron background environment during the LHC running. In order to verify the safe operation of these detectors, an irradiation test has been carried out with two RPCs at high neutron flux (about ), integrating values of dose and fluence equivalent to 10 LHC-years. Before and after the irradiation, the performance of the detectors was studied with cosmic muons, showing no relevant aging effects. Moreover, no indication of damage or chemical changes were observed on the electrode surfaces

    Experimental results on RPC neutron sensitivity

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    Abstract RPC neutron sensitivity has been studied during two tests done with different neutrons energies. In the first test, neutrons from spontaneous fission events of 252 Cf were used (average energy 2 MeV ); while in the second test neutrons were produced using a 50 MeV deuteron beam on a 1 cm thick beryllium target (average energy 20 MeV ). Preliminary results show that the neutron sensitivity in double gap mode is (0.52±0.03)×10−3 at about 2 MeV and (5.3±0.5)×10−3 at about 20 MeV

    Physical Mapping of Bread Wheat Chromosome 5A: An Integrated Approach

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    The huge size, redundancy, and highly repetitive nature of the bread wheat [Triticum aestivum (L.)] genome, makes it among the most difficult species to be sequenced. To overcome these limitations, a strategy based on the separation of individual chromosomes or chromosome arms and the subsequent production of physical maps was established within the frame of the International Wheat Genome Sequence Consortium (IWGSC). A total of 95,812 bacterial artificial chromosome (BAC) clones of short-arm chromosome 5A (5AS) and long-arm chromosome 5A (5AL) arm-specific BAC libraries were fingerprinted and assembled into contigs by complementary analytical approaches based on the FingerPrinted Contig (FPC) and Linear Topological Contig (LTC) tools. Combined anchoring approaches based on polymerase chain reaction (PCR) marker screening, microarray, and sequence homology searches applied to several genomic tools (i. e., genetic maps, deletion bin map, neighbor maps, BAC end sequences (BESs), genome zipper, and chromosome survey sequences) allowed the development of a high-quality physical map with an anchored physical coverage of 75% for 5AS and 53% for 5AL with high portions (64 and 48%, respectively) of contigs ordered along the chromosome. In the genome of grasses, Brachypodium [Brachypodium distachyon (L.) Beauv.], rice (Oryza sativa L.), and sorghum [Sorghum bicolor (L.) Moench] homologs of genes on wheat chromosome 5A were separated into syntenic blocks on different chromosomes as a result of translocations and inversions during evolution. The physical map presented represents an essential resource for fine genetic mapping and map-based cloning of agronomically relevant traits and a reference for the 5A sequencing projects
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