3,062 research outputs found

    Outsourcing the Human Resource Function: Environmental and Organizational Characteristics that Affect HR Performance

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    A theoretical model is presented that identifies environmental and organizational characteristics that affect human resource (HR) performance in an organization. Specifically, we address the issue of when and under what circumstances does HR outsourcing contribute value to the firm by attempting to identify environmental and organizational characteristics that affect HR department performance and how HR outsourcing mediates that relationship. We propose that supplier competition in the HR provider market has a direct effect on the amount of HR outsourcing which in turn has a direct effect on HR performance. Environmental uncertainty (primary, competitive, and supplier) is proposed to moderate the relationship between amount of HR outsourcing and HR performance while asset specificity is proposed to moderate the relationship between supplier competition and amount of HR outsourcing. An earlier version of this paper was presented at the Southwest Academy of Management meeting in Houston, Texas, March, 2003, and received the 2003 Irwin/McGraw-Hill Distinguished Paper Awar

    Undoped Electron-Hole Bilayers in a GaAs/AlGaAs Double Quantum Well

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    We present the fabrication details of completely undoped electron-hole bilayer devices in a GaAs/AlGaAs double quantum well heterostructure with a 30 nm barrier. These devices have independently tunable densities of the two-dimensional electron gas and two-dimensional hole gas. We report four-terminal transport measurements of the independently contacted electron and hole layers with balanced densities from 1.2×10111.2 \times 10^{11}cm2^{-2} down to 4×10104 \times 10^{10} cm2^{-2} at T=300mKT = 300 mK. The mobilities can exceed 1×1061 \times 10^{6} cm2^{2} V1^{-1} s1^{-1} for electrons and 4×1054 \times 10^{5} cm2^{2} V1^{-1} s1^{-1} for holes.Comment: 3 pages, 3 figure

    zCOSMOS: A large VLT/VIMOS redshift survey covering 0 < z < 3 in the COSMOS field

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    zCOSMOS is a large-redshift survey that is being undertaken in the COSMOS field using 600 hr of observation with the VIMOS spectrograph on the 8 m VLT. The survey is designed to characterize the environments of COSMOS galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCOSMOS survey consists of two parts: (1) zCOSMOSbright, a magnitude-limited I-band I_(AB) < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg^2 COSMOS ACS field, for which the survey parameters at z ~ 0.7 are designed to be directly comparable to those of the 2dFGRS at z ~ 0.1; and (2) zCOSMOS-deep, a survey of approximately 10,000 galaxies selected through color-selection criteria to have 1.4 < z < 3.0, within the central 1 deg^2. This paper describes the survey design and the construction of the target catalogs and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCOSMOS-bright targets and 977 zCOSMOS-deep targets have been obtained. These are briefly analyzed to demonstrate the characteristics that may be expected from zCOSMOS, and particularly zCOSMOS-bright, when it is finally completed between 2008 and 2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. These techniques bring the overall success rate in the zCOSMOS-bright so far to almost 90% and to above 97% in the 0.5 < z < 0.8 redshift range. Our zCOSMOS-deep spectra demonstrate the power of our selection techniques to isolate high-redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines

    THE CANADA-FRANCE REDSHIFT SURVEY IX: HST Imaging of High-Redshift Field Galaxies

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    HST B and I images are presented of 32 CFRS galaxies with secure redshifts in the range 0.5 < z < 1.2. These galaxies exhibit the same range of morphological types as seen locally, i.e., ellipticals, spirals and irregulars. The galaxies look far less regular in the BB images (rest-frame ultraviolet) than at longer wavelengths, underlining the fact that optical images of galaxies at still higher redshift should be interpreted with caution. Quantitative analyses of the galaxies yield disk sizes, bulge fractions, and colors for each component. At these redshifts, galaxy disks show clear evidence for surface brightness evolution. The mean rest-frame central surface brightness of the disks of normal late-type galaxies is mu_{AB}(B)=20.2 \pm 0.25 mag arcsec^{-2}, about 1.2 mag brighter than the Freeman (1970) value. Some degree of peculiarity is measurable in 10 (30%) of the galaxies and 4 (13%) show clear signs of interaction/mergers. There are 9 galaxies (30%) dominated by blue compact components. These components, which appear to be related to star formation, occur most often in peculiar/asymmetric galaxies (some of which appear to be interacting), but a few are in otherwise normal galaxies. Thus, of the galaxies bluer than present-day Sb, one-third are "blue nucleated galaxies", and half are late-type galaxies with disks which are significantly brighter than normal galaxies at z=0. Taken together, these two effects must be responsible for much of the observed evolution of the luminosity function of blue galaxies.Comment: uuencoded compressed postscript, 8 pages, 1 table + 5 figures in a separate part. Also available at http://www.astro.utoronto.ca/~lilly/CFRS/ . Accepted for publication in ApJ Letter

    Scattering Mechanism in Modulation-Doped Shallow Two-Dimensional Electron Gases

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    We report on a systematic investigation of the dominant scattering mechanism in shallow two-dimensional electron gases (2DEGs) formed in modulation-doped GaAs/Al_{x}Ga_{1-x}As heterostructures. The power-law exponent of the electron mobility versus density, mu \propto n^{alpha}, is extracted as a function of the 2DEG's depth. When shallower than 130 nm from the surface, the power-law exponent of the 2DEG, as well as the mobility, drops from alpha \simeq 1.65 (130 nm deep) to alpha \simeq 1.3 (60 nm deep). Our results for shallow 2DEGs are consistent with theoretical expectations for scattering by remote dopants, in contrast to the mobility-limiting background charged impurities of deeper heterostructures.Comment: 4 pages, 3 figures, modified version as accepted in AP

    Photo-z Performance for Precision Cosmology II : Empirical Verification

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    The success of future large scale weak lensing surveys will critically depend on the accurate estimation of photometric redshifts of very large samples of galaxies. This in turn depends on both the quality of the photometric data and the photo-z estimators. In a previous study, (Bordoloi et al. 2010) we focussed primarily on the impact of photometric quality on photo-z estimates and on the development of novel techniques to construct the N(z) of tomographic bins at the high level of precision required for precision cosmology, as well as the correction of issues such as imprecise corrections for Galactic reddening. We used the same set of templates to generate the simulated photometry as were then used in the photo-z code, thereby removing any effects of "template error". In this work we now include the effects of "template error" by generating simulated photometric data set from actual COSMOS photometry. We use the trick of simulating redder photometry of galaxies at higher redshifts by using a bluer set of passbands on low z galaxies with known redshifts. We find that "template error" is a rather small factor in photo-z performance, at the photometric precision and filter complement expected for all-sky surveys. With only a small sub-set of training galaxies with spectroscopic redshifts, it is in principle possible to construct tomographic redshift bins whose mean redshift is known, from photo-z alone, to the required accuracy of 0.002(1+z).Comment: 7 pages, 5 figures, accepted for publication in MNRA

    High spatial resolution observations of CUDSS14A: a SCUBA-selected ultraluminous galaxy at high redshift

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    The definitive version is available at www.blackwell-synergy.com '. Copyright Blackwell Publishing DOI : 10.1046/j.1365-8711.2000.03822.xWe present a high-resolutionmillimetre interferometric image of the brightest SCUBA- selected galaxy from the Canada-UK deep SCUBA survey (CUDSS). We make a very clear detection at 1.3 mm, but fail to resolve any structure in the source.Peer reviewe
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