767 research outputs found
Human Resource Outsourcing: Long Term Operating Performance Effects From The Providers Perspective
Human resource (HR) outsourcing research has primarily focused on the client with little attention paid to the service provider. As an initial step in understanding this important stakeholder in the HR outsourcing relationship, this study focuses on the financial performance of HR service firms that publicly announce outsourcing contracts. From the provider’s perspective, we investigate firm performance changes subsequent to outsourcing contract announcements, using a sample of 94 publicly available press releases. Our tests show that in the long term, small HR service providers contracted by large client firms experience improvements in operating profitability and margins
Comparison of photoexcited p-InAs THz radiation source with conventional thermal radiation sources
P-type InAs excited by ultrashort optical pulses has been shown to be a strong emitter of terahertz radiation. In a direct comparison between a p-InAs emitter and conventional thermal radiation sources, we demonstrate that under typical excitation conditions p-InAs produces more radiation below 1.2 THz than a globar. By treating the globar as a blackbody emitter we calibrate a silicon bolometer which is used to determine the power of the p-InAs emitter. The emitted terahertz power was found to be 98±10 nW in this experiment
Slipping friction of an optically and magnetically manipulated microsphere rolling at a glass-water interface
The motion of submerged magnetic microspheres rolling at a glass-water
interface has been studied using magnetic rotation and optical tweezers
combined with bright-field microscopy particle tracking techniques. Individual
microspheres of varying surface roughness were magnetically rotated both in and
out of an optical trap to induce rolling, along either plain glass cover slides
or glass cover slides functionalized with polyethylene glycol. It has been
observed that the manipulated microspheres exhibited nonlinear dynamic
rolling-while-slipping motion characterized by two motional regimes: At low
rotational frequencies, the speed of microspheres free-rolling along the
surface increased proportionately with magnetic rotation rate; however, a
further increase in the rotation frequency beyond a certain threshold revealed
a sharp transition to a motion in which the microspheres slipped with respect
to the external magnetic field resulting in decreased rolling speeds. The
effects of surface-microsphere interactions on the position of this threshold
frequency are posed and investigated. Similar experiments with microspheres
rolling while slipping in an optical trap showed congruent results.Comment: submitted to Journal of Applied Physics, 11 figure
Effect of \u3ci\u3eLactobacillus acidophilus\u3c/i\u3e Strain N P51 on\u3ci\u3e Escherichia coli \u3c/i\u3e0157:H7 Fecal Shedding and Finishing Performance in Beef Feedlot Cattle
A 2-year study was conducted during the summer months (May to September) to test the effectiveness of feeding Lactobacillus acidophilus strain NP51 on the proportion of cattle shedding Escherichia coli 0157:H7 in the feces and evaluate the effect of the treatment on finishing performance. Steers (n = 448) were assigned randomly to pens, and pens of cattle were assigned randomly to NP5 1 supplementation or no supplementation (control). NP5 1 products were mixed with water and applied as the feed was mixed daily in treatment-designated trucks at the rate of l09 CFU per steer. Fecal samples were collected (n = 3,360) from the rectum from each animal every 3 weeks, and E. coli 0157:H7 was isolated by standard procedures, using selective enrichment, immunomagnetic separation, and PCR confirmation. The outcome variable was the recovery of E. coli 0157:H7 from feces, and was modeled using logistic regression accounting for year, repeated measures of pens of cattle, and block. No significant differences were detected for gain, intakes, or feed efficiency of control or NP51-fed steers. The probability for cattle to shed E. coli 0157:H7 varied significantly between 2002 and 2003 (P = 0.004). In 2002 and 2003, the probability for NP5 1-treated steers to shed E. coli 0157:H7 over the test periods was 13 and 21 %, respectively, compared with 21 and 28% among controls. Over the 2 years, NP51-treated steers were 35% less likely to shed E. coli 0157: H7 than were steers in untreated pens (odds ratio = 0.58, P = 0.008). This study is consistent with previous reports that feeding NP51 is effective in reducing E. coli 0157:H7 fecal shedding in feedlot cattle
Evaluation of the Value of Fiber in Distillers Grains Plus Solubles on Performance of Finishing Cattle
A finishing study was conducted to determine the value of the fiber in distillers grains plus solubles on cattle performance. Five treatments were evaluated: a corn control diet, 20 or 40% modified distillers grains plus solubles, plus two diets containing corn germ meal and corn bran balanced to equal the fiber content of the two modified distillers grains plus solubles diets. Th ere was a significant improvement in ADG and F:G for cattle fed modified distillers grains plus solubles compared to control. Cattle fed the corn germ meal and bran diets had increased DMI, slightly lower ADG, and poorer F:G compared to the control. Th e isolated fiber component had 83– 90% the feeding value of corn, while modified distillers grains plus solubles had 107– 108%. Other components in distillers besides fiber must improve the value of distillers compared to corn
Bat-associated Rabies Virus in Skunks
Rabies was undetected in terrestrial wildlife of northern Arizona until 2001, when rabies was diagnosed in 19 rabid skunks in Flagstaff. Laboratory analyses showed causative rabies viruses associated with bats, which indicated cross-species transmission of unprecedented magnitude. Public health infrastructure must be maintained to address emerging zoonotic diseases
Cosmological Constraints from Measurements of Type Ia Supernovae discovered during the first 1.5 years of the Pan-STARRS1 Survey
We present griz light curves of 146 spectroscopically confirmed Type Ia
Supernovae () discovered during the first 1.5 years of the
Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is
determined by a combination of on-site measurements of the instrument response
function and observations of spectrophotometric standard stars. We find that
the systematic uncertainties in the photometric system are currently 1.2\%
without accounting for the uncertainty in the HST Calspec definition of the AB
system. A Hubble diagram is constructed with a subset of 113 out of 146 SNe Ia
that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113
PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only SNe and
assuming a constant dark energy equation of state and flatness, yields
.
When combined with BAO+CMB(Planck)+, the analysis yields and including all
identified systematics (see also Scolnic et al. 2014). The value of is
inconsistent with the cosmological constant value of at the 2.3
level. Tension endures after removing either the BAO or the constraint,
though it is strongest when including the constraint. If we include WMAP9
CMB constraints instead of those from Planck, we find
, which diminishes the discord to . We
cannot conclude whether the tension with flat CDM is a feature of dark
energy, new physics, or a combination of chance and systematic errors. The full
Pan-STARRS1 supernova sample with 3 times as many SNe should provide
more conclusive results.Comment: 38 pages, 16 figures, 14 tables, ApJ in pres
Pan-STARRS1 Discovery of Two Ultra-Luminous Supernovae at z ~ 0.9
We present the discovery of two ultra-luminous supernovae (SNe) at z ~ 0.9
with the Pan-STARRS1 Medium-Deep Survey. These SNe, PS1-10ky and PS1-10awh, are
amongst the most luminous SNe ever discovered, comparable to the unusual
transients SN 2005ap and SCP 06F6. Like SN 2005ap and SCP 06F6, they show
characteristic high luminosities (M_bol ~ -22.5 mag), blue spectra with a few
broad absorption lines, and no evidence for H or He. We have constructed a full
multi-color light curve sensitive to the peak of the spectral energy
distribution in the rest-frame ultraviolet, and we have obtained time-series
spectroscopy for these SNe. Given the similarities between the SNe, we combine
their light curves to estimate a total radiated energy over the course of
explosion of (0.9-1.4) x 10^51 erg. We find photospheric velocities of
12,000-19,000 km/s with no evidence for deceleration measured across ~3
rest-frame weeks around light-curve peak, consistent with the expansion of an
optically-thick massive shell of material. We show that, consistent with
findings for other ultra-luminous SNe in this class, radioactive decay is not
sufficient to power PS1-10ky, and we discuss two plausible origins for these
events: the initial spin-down of a newborn magnetar in a core-collapse SN, or
SN shock breakout from the dense circumstellar wind surrounding a Wolf-Rayet
star.Comment: Re-Submitted to Ap
Systematic Uncertainties Associated with the Cosmological Analysis of the First Pan-STARRS1 Type Ia Supernova Sample
We probe the systematic uncertainties from 113 Type Ia supernovae (SNIa) in
the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of
low-redshift surveys. The companion paper by Rest et al. (2013) describes the
photometric measurements and cosmological inferences from the PS1 sample. The
largest systematic uncertainty stems from the photometric calibration of the
PS1 and low-z samples. We increase the sample of observed Calspec standards
from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II
calibration systems are compared and discrepancies up to ~0.02 mag are
recovered. We find uncertainties in the proper way to treat intrinsic colors
and reddening produce differences in the recovered value of w up to 3%. We
estimate masses of host galaxies of PS1 supernovae and detect an insignificant
difference in distance residuals of the full sample of 0.037\pm0.031 mag for
host galaxies with high and low masses. Assuming flatness in our analysis of
only SNe measurements, we find . With additional constraints from BAO,
CMB(Planck) and H0 measurements, we find and
(statistical and systematic errors added in
quadrature). Significance of the inconsistency with depends on whether
we use Planck or WMAP measurements of the CMB:
.Comment: 24 pages, 20 figures. Accepted by Ap
Results from the Supernova Photometric Classification Challenge
We report results from the Supernova Photometric Classification Challenge
(SNPCC), a publicly released mix of simulated supernovae (SNe), with types (Ia,
Ibc, and II) selected in proportion to their expected rate. The simulation was
realized in the griz filters of the Dark Energy Survey (DES) with realistic
observing conditions (sky noise, point-spread function and atmospheric
transparency) based on years of recorded conditions at the DES site.
Simulations of non-Ia type SNe are based on spectroscopically confirmed light
curves that include unpublished non-Ia samples donated from the Carnegie
Supernova Project (CSP), the Supernova Legacy Survey (SNLS), and the Sloan
Digital Sky Survey-II (SDSS-II). A spectroscopically confirmed subset was
provided for training. We challenged scientists to run their classification
algorithms and report a type and photo-z for each SN. Participants from 10
groups contributed 13 entries for the sample that included a host-galaxy
photo-z for each SN, and 9 entries for the sample that had no redshift
information. Several different classification strategies resulted in similar
performance, and for all entries the performance was significantly better for
the training subset than for the unconfirmed sample. For the spectroscopically
unconfirmed subset, the entry with the highest average figure of merit for
classifying SNe~Ia has an efficiency of 0.96 and an SN~Ia purity of 0.79. As a
public resource for the future development of photometric SN classification and
photo-z estimators, we have released updated simulations with improvements
based on our experience from the SNPCC, added samples corresponding to the
Large Synoptic Survey Telescope (LSST) and the SDSS, and provided the answer
keys so that developers can evaluate their own analysis.Comment: accepted by PAS
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