5,125 research outputs found

    Pax5 maintains cellular identity by repressing gene expression throughout B cell differentiation.

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    The transcription factor Pax5 is required for many aspects of B-lymphopoiesis including lineage commitment, immunoglobulin rearrangement, pre-BCR signalling and mature B cell survival. Pax5 regulates B cell lineage commitment by concurrently activating B cell specific gene expression as well as suppressing the expression of genes associated with non-B cell fates. The identity of the molecular targets of Pax5-mediated gene repression is the subject of much current interest. Recent studies have documented the essential nature of the Pax5 repression of the stem cell transcriptional program, as well as the silencing of lineage inappropriate gene expression, for B cell development. Surprisingly the repression of genes by Pax5 continues throughout lymphopoiesis, with the loss of Pax5 in mature B cell resulting in the reactivation of the same Pax5 targets during plasma cell differentiation. These recent insights into the mechanism of action of Pax5 in controlling B cell identity will be discussed

    Low emotional response to traumatic footage is associated with an absence of analogue flashbacks: An individual participant data meta-analysis of 16 trauma film paradigm experiments.

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    Most people will experience or witness a traumatic event. A common occurrence after trauma is the experience of involuntary emotional memories of the traumatic event, herewith "flashbacks". Some individuals, however, report no flashbacks. Prospective work investigating psychological factors associated with an absence of flashbacks is lacking. We performed an individual participant data meta-analysis on 16 experiments (n = 458) using the trauma film paradigm to investigate the association of emotional response to traumatic film footage and commonly collected baseline characteristics (trait anxiety, current depression, trauma history) with an absence of analogue flashbacks. An absence of analogue flashbacks was associated with low emotional response to the traumatic film footage and, to a lesser extent, low trait anxiety and low current depression levels. Trauma history and recognition memory for the film were not significantly associated with an absence of analogue flashbacks. Understanding why some individuals report an absence of flashbacks may aid preventative treatments against flashback development

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

    Combined search for the quarks of a sequential fourth generation

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    Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Pax5 maintains cellular identity by repressing gene expression throughout B cell differentiation.

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    The transcription factor Pax5 is required for many aspects of B-lymphopoiesis including lineage commitment, immunoglobulin rearrangement, pre-BCR signalling and mature B cell survival. Pax5 regulates B cell lineage commitment by concurrently activating cell specific gene expression as well as suppressing the expression of genes associated with non-B cell fates. The identity of the molecular targets of Pax5-mediated gene repression is the subject of much current interest. Recent studies have documented the essential nature of the Pax5 mediated repression of the stem cell transcriptional program, as well as the silencing of lineage inappropriate gene expression, for B cell development. Surprisingly the repression of genes by Pax5 continues throughout lymphopoiesis, with the loss of Pax5 in mature B cell resulting in the reactivation of the same Pax5 targets during plasma cell differentiation. These recent insights into the mechanism of action of Pax5 in controlling B cell identity will be discussed

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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