803 research outputs found

    Integration and Conventional Systems at STAR

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    At the beginning of the design and construction of the STAR Detector, the collaboration assigned a team of physicists and engineers the responsibility of coordinating the construction of the detector. This group managed the general space assignments for each sub-system and coordinated the assembly and planning for the detector. Furthermore, as this group was the only STAR group with the responsibility of looking at the system as a whole, the collaboration assigned it several tasks that spanned the different sub-detectors. These items included grounding, rack layout, cable distribution, electrical, power and water, and safety systems. This paper describes these systems and their performance.Comment: 17 pages, 6 figures, Contribution to a NIM Volume Dedicated to the Detectors and the Accelerator at RHI

    REMOVAL OF MANGANESE FROM AN ALKALINE MINE DRAINAGE USING A BIOREACTOR WITH DIFFERENT ORGANIC CARBON SOURCES

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    The treatment of Mn and SO42- contaminated mine drainage via a sulfate reducing bioreactor is expected to result in near-permanent immobilization of significant amounts of Mn and a portion of the sulfates within the matrix. This study tested several different combinations of organic amendments and inorganic substrates in an attempt to optimize sulfate reducing conditions and Mn removal capacity. Five different organic carbon sources, including corn mash, wood mulch, biosolids, soybean oil, and sorghum syrup in combination with five different inorganic substrates, including creek sediment, marble and limestone chips, polished gravel, and sand were tested in batch experiments. Results indicate a widely Mn variant removal potential among the treatments, ranging from 35% for soybean oil to 97% for the mulch mixture, with respective Eh ranges of +60 mV and -320 mV. Sulfate removal ranged from less than 10% to 85%. The most favorable combinations were tested in small scale bioreactors under dynamic conditions. Greater than 90% of Mn and 70% of sulfate was removed over a 65 day test period. Results indicate Mn removal mechanisms include sulfide, oxide, and carbonate formation and simple sorption and SO42- removal mechanisms of sulfide gas evolution, gypsum and MnS precipitation, and anion sorption/cation bridging

    Color-blind racial attitudes: Microaggressions in the context of racism and White privilege

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    Interest in institutional racism, White privilege, and microaggressions appears to be growing. We are living in times when the impact of race and racism are debated—when even the existence of racism is debated along with the appropriateness of examining the worst parts of U.S. history. This special-issue invited article includes a brief examination of historical information and current context in which racism and microaggressions exist, leading to their connections to Color-Blind Racial Attitudes (CoBRAs). Reviewed research on CoBRAs addresses teacher training, educational practices, experiences on college campuses, and organizational management

    Career Barriers in Freshman Orientation: What are first year students worried about?

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    The goal of this study was to identify the career barriers facing college students in their first semester with the possibility of addressing those concerns through campus programing or freshman orientation

    Presenting Information About White Privilege and Systemic Racism: Message vs. Messenger

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    In our study, we found evidence for some effect on how students perceive information about systemic racism and White privilege based on the perceived identity of the presenter

    How Students View Diversity in Their Education: A Qualitative Examination

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    In this study, we examined students’ open responses to questions regarding their opinions about diversity on their college campus. Here, we report on responses about age, religion, and political views in the classroom and outside the classroom

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon μ\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, μμ\mu\mu or eμe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    Inclusive search for same-sign dilepton signatures in pp collisions at root s=7 TeV with the ATLAS detector

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    An inclusive search is presented for new physics in events with two isolated leptons (e or mu) having the same electric charge. The data are selected from events collected from p p collisions at root s = 7 TeV by the ATLAS detector and correspond to an integrated luminosity of 34 pb(-1). The spectra in dilepton invariant mass, missing transverse momentum and jet multiplicity are presented and compared to Standard Model predictions. In this event sample, no evidence is found for contributions beyond those of the Standard Model. Limits are set on the cross-section in a fiducial region for new sources of same-sign high-mass dilepton events in the ee, e mu and mu mu channels. Four models predicting same-sign dilepton signals are constrained: two descriptions of Majorana neutrinos, a cascade topology similar to supersymmetry or universal extra dimensions, and fourth generation d-type quarks. Assuming a new physics scale of 1 TeV, Majorana neutrinos produced by an effective operator V with masses below 460 GeV are excluded at 95% confidence level. A lower limit of 290 GeV is set at 95% confidence level on the mass of fourth generation d-type quarks

    Measurement of inclusive two-particle angular correlations in pp collisions with the ATLAS detector at the LHC

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    We present a measurement of two-particle angular correlations in proton- proton collisions at s√=900 GeV and 7 TeV. The collision events were collected during 2009 and 2010 with the ATLAS detector at the Large Hadron Collider using a single-arm minimum bias trigger. Correlations are measured for charged particles produced in the kinematic range of transverse momentum p T  > 100 MeV and pseudorapidity |η| < 2.5. A complex structure in pseudorapidity and azimuth is observed at both collision energies. Results are compared to pythia 8 and herwig++ as well as to the AMBT2B, DW and Perugia 2011 tunes of pythia 6. The data are not satisfactorily described by any of these models
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