220 research outputs found

    A Meta-Analytic Study of Downsizing: Behaviors and Attitudes Prevalent Among Supervisors

    Get PDF
    Current research into the effect of downsizing, restructuring, and force reduction on employees has approached the issue many possible vantage points it has focused on the victims, the survivors, and sometimes both. Researchers in management science and psychology explain responses we can expect from survivors of such a corporate upheaval. These effects are of particular interest to supervisors, because they will inevitably face a workforce, at least partially staffed with such survivors. To clarify possible attitudes and behaviors in tomorrow’s work environment, our study tied together, through meta- analysis, results of studies on survivors of a downsized organization. The completed analysis enables managers to preview in the aggregate sense a certain set of downsizing survivor responses. A questionnaire was used to gather added data on survivor’s reactions to and feelings about their organization. The results were incorporated into the meta-analysis statistics, and credibility intervals established. This interval will serve to identify the true population correlations for the variable relationships presented in the current research literature

    A segmented Hybrid Photon Detector with integrated auto-triggering front-end electronics for a PET scanner

    Get PDF
    We describe the design, fabrication and test results of a segmented Hybrid Photon Detector with integrated auto-triggering front-end electronics. Both the photodetector and its VLSI readout electronics are custom designed and have been tailored to the requirements of a recently proposed novel geometrical concept of a Positron Emission Tomograph. Emphasis is put on the PET specific features of the device. The detector has been fabricated in the photocathode facility at CERN

    Optimization of the effective light attenuation length of YAP:Ce and LYSO:Ce crystals for a novel geometrical PET concept

    Get PDF
    Abstract The effective light attenuation length in thin bars of polished YAP:Ce and LYSO:Ce scintillators with lengths of the order of 10 cm has been studied for various wrappings and coatings of the crystal lateral surfaces. This physical parameter plays a key role in a novel 3D PET concept based on axial arrays of long scintillator bars read out at both ends by Hybrid Photodetectors (HPDs) since it influences the spatial, energy and time resolutions of such a device. In this paper we show that the effective light attenuation length of polished crystals can be reduced by wrapping their lateral surfaces with Teflon, or tuned to the desired value by depositing a coating of Cr or Au of well-defined thickness. The studies have been carried out with YAP and LYSO long scintillator bars, read out by standard photomultiplier tubes. Even if the novel PET device will use different scintillators and HPD readout, the results described here prove the feasibility of an important aspect of the concept and provide hints on the potential capabilities of the device

    Transverse-target-spin asymmetry in exclusive ω\omega-meson electroproduction

    Get PDF
    Hard exclusive electroproduction of ω\omega mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive πω\pi\omega transition form factor.Comment: DESY Report 15-14

    Beam-helicity asymmetries for single-hadron production in semi-inclusive deep-inelastic scattering from unpolarized hydrogen and deuterium targets

    Get PDF
    A measurement of beam-helicity asymmetries for single-hadron production in deep-inelastic scattering is presented. Data from the scattering of 27.6 GeV electrons and positrons off gaseous hydrogen and deuterium targets were collected by the HERMES experiment. The asymmetries are presented separately as a function of the Bjorken scaling variable, the hadron transverse momentum, and the fractional energy for charged pions and kaons as well as for protons and anti-protons. These asymmetries are also presented as a function of the three aforementioned kinematic variables simultaneously

    Single Spin Asymmetries of Inclusive Hadrons Produced in Electron Scattering from a Transversely Polarized 3^3He Target

    Full text link
    We report the first measurement of target single-spin asymmetries (AN_N) in the inclusive hadron production reaction, e e~+ 3Heh+X~^3\text{He}^{\uparrow}\rightarrow h+X, using a transversely polarized 3^3He target. The experiment was conducted at Jefferson Lab in Hall A using a 5.9-GeV electron beam. Three types of hadrons (π±\pi^{\pm}, K±\text{K}^{\pm} and proton) were detected in the transverse hadron momentum range 0.54 <pT<<p_T< 0.74 GeV/c. The range of xFx_F for pions was -0.29 <xF<<x_F< -0.23 and for kaons -0.25 <xF<<x_F<-0.18. The observed asymmetry strongly depends on the type of hadron. A positive asymmetry is observed for π+\pi^+ and K+\text{K}^+. A negative asymmetry is observed for π\pi^{-}. The magnitudes of the asymmetries follow Aπ<Aπ+<AK+|A^{\pi^-}| < |A^{\pi^+}| < |A^{K^+}|. The K^{-} and proton asymmetries are consistent with zero within the experimental uncertainties. The π+\pi^{+} and π\pi^{-} asymmetries measured for the 3^3He target and extracted for neutrons are opposite in sign with a small increase observed as a function of pTp_T.Comment: Updated version, submitted to Phys. Rev.

    Measurement of pretzelosity asymmetry of charged pion production in Semi-Inclusive Deep Inelastic Scattering on a polarized 3^3He target

    Full text link
    An experiment to measure single-spin asymmetries in semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized 3^3He target was performed at Jefferson Lab in the kinematic region of 0.16<x<0.350.16<x<0.35 and 1.4<Q2<2.71.4<Q^2<2.7 GeV2{\rm GeV^2}. The pretzelosity asymmetries on 3^3He, which can be expressed as the convolution of the h1Th^\perp_{1T} transverse momentum dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Using the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured 3^3He asymmetries and cross-section ratios between the proton and 3^3He. Our results show that for both π±\pi^{\pm} on 3^3He and on the neutron the pretzelosity asymmetries are consistent with zero within experimental uncertainties.Comment: 6 pages, 3 figures; enlarged the legends in Fig.3; added 3 citation

    Single Spin Asymmetries in Charged Kaon Production from Semi-Inclusive Deep Inelastic Scattering on a Transversely Polarized 3He^3{\rm{He}} Target

    Full text link
    We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized 3He^3{\rm{He}} target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1<<xbjx_{bj}<<0.4 for K+K^{+} and KK^{-} production. While the Collins and Sivers moments for K+K^{+} are consistent with zero within the experimental uncertainties, both moments for KK^{-} favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While the K+K^{+} Sivers moments are consistent with the prediction, the KK^{-} results differ from the prediction at the 2-sigma level.Comment: 6 pages, 3 figure

    Double Spin Asymmetries of Inclusive Hadron Electroproductions from a Transversely Polarized 3He^3\rm{He} Target

    Get PDF
    We report the measurement of beam-target double-spin asymmetries (ALTA_\text{LT}) in the inclusive production of identified hadrons, e \vec{e}~+ 3Heh+X~^3\text{He}^{\uparrow}\rightarrow h+X, using a longitudinally polarized 5.9 GeV electron beam and a transversely polarized 3He^3\rm{He} target. Hadrons (π±\pi^{\pm}, K±K^{\pm} and proton) were detected at 16^{\circ} with an average momentum =2.35 GeV/c and a transverse momentum (pTp_{T}) coverage from 0.60 to 0.68 GeV/c. Asymmetries from the 3He^3\text{He} target were observed to be non-zero for π±\pi^{\pm} production when the target was polarized transversely in the horizontal plane. The π+\pi^{+} and π\pi^{-} asymmetries have opposite signs, analogous to the behavior of ALTA_\text{LT} in semi-inclusive deep-inelastic scattering.Comment: Published in PRC (92.015207), nuclear experiment, high-energy experimen
    corecore