89 research outputs found

    Relative spins and excitation energies of superdeformed bands in 190Hg: Further evidence for octupole vibration

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    An experiment using the Eurogam Phase II gamma-ray spectrometer confirms the existence of an excited superdeformed (SD) band in 190Hg and its very unusual decay into the lowest SD band over 3-4 transitions. The energies and dipole character of the transitions linking the two SD bands have been firmly established. Comparisons with RPA calculations indicate that the excited SD band can be interpreted as an octupole-vibrational structure.Comment: 12 pages, latex, 4 figures available via WWW at http://www.phy.anl.gov/bgo/bc/hg190_nucl_ex.htm

    Diurnal rhythmic expression of the rhythm-related genes, rPeriod1, rPeriod2, and rClock , in the rat brain

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    High densities of the mRNA of three rhythm-related genes, rPeriod1 (rPer1), rPer2 , and rClock , which share high homology in Drosophila and mammals, are found in the rat hypothalamic suprachiasmatic nucleus (SCN). The SCN, however, is not the only brain region that expresses these genes. To understand the possible physiological roles of these rhythm-related genes, we examined expression of these genes in different brain regions at various time points in male Sprague--Dawley rats. Using semi quantitative in situ hybridization with 35 S-riboprobes to evaluate mRNA levels, the diurnal rhythmicity of rPer1, and rPer2 mRNA levels was found in the SCN, arcuate nucleus, and median eminence/pars tuberalis. Expression patterns of mRNA for rPer1 and rPer2 , however, were not similar in these brain regions. The rhythmicity in these brain regions was specific, because it was not observed in the cerebellum or hippocampus. Moreover, diurnal changes in rClock mRNA expression were not detected in any of the brain regions examined. These findings suggest that the different expression patterns observed for rPer1, rPer2 , and rClock mRNAs may be attributed to their different physiological roles in these brain regions, and support previous work indicating that circadian rhythms in the brain are widespread.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43939/1/11373_2004_Article_8176.pd

    Measurement of the muon flux from 400 GeV/c protons interacting in a thick molybdenum/tungsten target

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    The SHiP experiment is proposed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. About 1011 muons per spill will be produced in the dump. To design the experiment such that the muon-induced background is minimized, a precise knowledge of the muon spectrum is required. To validate the muon flux generated by our Pythia and GEANT4 based Monte Carlo simulation (FairShip), we have measured the muon flux emanating from a SHiP-like target at the SPS. This target, consisting of 13 interaction lengths of slabs of molybdenum and tungsten, followed by a 2.4 m iron hadron absorber was placed in the H4 400 GeV/c proton beam line. To identify muons and to measure the momentum spectrum, a spectrometer instrumented with drift tubes and a muon tagger were used. During a 3-week period a dataset for analysis corresponding to (3.27±0.07) × 1011 protons on target was recorded. This amounts to approximatively 1% of a SHiP spill

    Track reconstruction and matching between emulsion and silicon pixel detectors for the SHiP-charm experiment

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    In July 2018 an optimization run for the proposed charm cross section measurement for SHiP was performed at the CERN SPS. A heavy, moving target instrumented with nuclear emulsion films followed by a silicon pixel tracker was installed in front of the Goliath magnet at the H4 proton beam-line. Behind the magnet, scintillating-fibre, drift-tube and RPC detectors were placed. The purpose of this run was to validate the measurement's feasibility, to develop the required analysis tools and fine-tune the detector layout. In this paper, we present the track reconstruction in the pixel tracker and the track matching with the moving emulsion detector. The pixel detector performed as expected and it is shown that, after proper alignment, a vertex matching rate of 87% is achieved

    Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry

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    Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase

    A Comparative Analysis of Sediment Transport and Deposition Trends of the Namib Sand Sea and Belet on Titan

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    International audienceIntroduction: Saturn's moon Titan has striking geomorphological similarities to Earth, including a pervasive set of eolian landforms. On both bodies, large linear dunes form into sand seas, which are sedimentary bodies transported and deposited by eolian processes [1]. On Titan, the sand seas are concentrated in the equatorial region and are very large; for example, the Belet Sand Sea is approximately 3.3 ± 0.6 million km 2 and has a sand volume of 610,000-1,270,000 km 3 [2,3,4]. Most present day terrestrial sand seas are significantly smaller than those on Titan. The largest sand sea on Earth, the Rub' al Khali, covers an area of ~560,000 km 2 [5]. The latitudes of sand seas on Earth also vary much more than sand seas on Titan, which is likely a reflection of climatic conditions related to Hadley circulation [6]. However, despite different atmospheric and compositional differences, the similarity in the shape and size of linear dunes of the Namib, Arabian, and Australian deserts and the Belet Sand Sea of Titan suggests that comparisons with them will yield a better understanding of Titan's dunes [6,7,8]. The morphology of linear dunes indicates there is the necessary wind strength and direction (with vector winds appro

    Selection, transmission, and reversion of an antigen-processing cytotoxic T-lymphocyte escape mutation in Human Immunodeficiency Virus Type 1 infection

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    Numerous studies now support that human immunodeficiency virus type 1 (HIV-1) evolution is influenced by immune selection pressure, with population studies showing an association between specific HLA alleles and mutations within defined cytotoxic T-lymphocyte epitopes. Here we combine sequence data and functional studies of CD8 T-cell responses to demonstrate that allele-specific immune pressures also select for mutations flanking CD8 epitopes that impair antigen processing. In persons expressing HLA-A3, we demonstrate consistent selection for a mutation in a C-terminal flanking residue of the normally immunodominant Gag KK9 epitope that prevents its processing and presentation, resulting in a rapid decline in the CD8 T-cell response. This single amino acid substitution also lies within a second HLA-A3-restricted epitope, with the mutation directly impairing recognition by CD8 T cells. Transmission of the mutation to subjects expressing HLA-A3 was shown to prevent the induction of normally immunodominant acute-phase responses to both epitopes. However, subsequent in vivo reversion of the mutation was coincident with delayed induction of new CD8 T-cell responses to both epitopes. These data demonstrate that mutations within the flanking region of an HIV-1 epitope can impair recognition by an established CD8 T-cell response and that transmission of these mutations alters the acute-phase CD8+ T-cell response. Moreover, reversion of these mutations in the absence of the original immune pressure reveals the potential plasticity of immunologically selected evolutionary changes
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