5,165 research outputs found

    The Dark Side of Performance Appraisals: A Study of University Librarians Across the U.S.

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    Performance appraisals are conducted regularly in professional organizations as a means to evaluate employee performance and overall company effectiveness. Employees and employers alike dread appraisal time; appraisals are often time consuming, tedious, and yield minimal positive results. Previous research has shown that employee perceptions of performance appraisals are important to consider when determining their overall effectiveness. In order to build new systems that could be viewed more positively by managers and employees, a deeper examination into the issues of performance appraisals, especially from the manager’s perspective, is needed. Our study looks at data gathered from a survey given to academic library directors, prompting them to evaluate the purposefulness of their current performance appraisal systems. Embedded in this survey is an open-ended response question, asking directors their perceptions of the PA system in their library. Our study seeks to determine if we can use text analytics create a better understanding of manager’s reactions and perceptions of PA systems and formats. We believe that the data gathered from the textual analysis will provide incremental validity into manager perceptions of performance appraisals and further insight into how organizations can improve their own processes

    Faraday Rotation of Extended Emission as a Probe of the Large-Scale Galactic Magnetic Field

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    The Galactic magnetic field is an integral constituent of the interstellar medium (ISM), and knowledge of its structure is crucial to understanding Galactic dynamics. The Rotation Measures (RM) of extragalactic (EG) sources have been the basis of comprehensive Galactic magnetic field models. Polarised extended emission (XE) is also seen along lines of sight through the Galactic disk, and also displays the effects of Faraday rotation. Our aim is to investigate and understand the relationship between EG and XE RMs near the Galactic plane, and to determine how the XE RMs, a hitherto unused resource, can be used as a probe of the large-scale Galactic magnetic field. We used polarisation data from the Canadian Galactic Plane Survey (CGPS), observed near 1420 MHz with the Dominion Radio Astrophysical Observatory (DRAO) Synthesis Telescope. We calculated RMs from a linear fit to the polarisation angles as a function of wavelength squared in four frequency channels, for both the EG sources and the XE. Across the CGPS area, 55<<193,3<b<555^{\circ} < {\ell} <193^{\circ}, -3^{\circ} < b < 5^{\circ}, the RMs of the XE closely track the RMs of the EG sources, with XE RMs about half the value of EG-source RMs. The exceptions are places where large local HII complexes heavily depolarise more distant emission. We conclude that there is valuable information in the XE RM dataset. The factor of 2 between the two types of RM values is close to that expected from a Burn slab model of the ISM. This result indicates that, at least in the outer Galaxy, the EG and XE sources are likely probing similar depths, and that the Faraday rotating medium and the synchrotron emitting medium have similar variation with galactocentric distance.Comment: Accepted to Galaxies, March 22, 201

    Baby-Led Weaning: The Evidence to Date

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    Purpose of ReviewInfants are traditionally introduced to solid foods using spoon-feeding of specially prepared infant foods.Recent FindingsHowever, over the last 10–15 years, an alternative approach termed ‘baby-led weaning’ has grown in popularity. This approach involves allowing infants to self-feed family foods, encouraging the infant to set the pace and intake of the meal. Proponents of the approach believe it promotes healthy eating behaviour and weight gain trajectories, and evidence is starting to build surrounding the method. This review brings together all empirical evidence to date examining behaviours associated with the approach, its outcomes and confounding factors.SummaryOverall, although there is limited evidence suggesting that a baby-led approach may encourage positive outcomes, limitations of the data leave these conclusions weak. Further research is needed, particularly to explore pathways to impact and understand the approach in different contexts and populations

    Velocity Dispersion of Dissolving OB Associations Affected by External Pressure of Formation Environment

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    This paper presents a possible way to understand dissolution of OB associations (or groups). Assuming rapid escape of parental cloud gas from associations, we show that the shadow of the formation environment for associations can be partially imprinted on the velocity dispersion at their dissolution. This conclusion is not surprising as long as associations are formed in a multiphase interstellar medium, because the external pressure should suppress expansion caused by the internal motion of the parental clouds. Our model predicts a few km s1^{-1} as the internal velocity dispersion. Observationally, the internal velocity dispersion is 1\sim 1 km s1^{-1} which is smaller than our prediction. This suggests that the dissipation of internal energy happens before the formation of OB associations.Comment: 6 pages. AJ accepte

    A low-density hot Jupiter in a near-aligned, 4.5-day orbit around a VV = 10.8, F5V star

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    We report the independent discovery and characterisation of a hot Jupiter in a 4.5-d, transiting orbit around the star TYC 7282-1298-1 (VV = 10.8, F5V). The planet has been pursued by the NGTS team as NGTS-2b and by ourselves as WASP-179b. We characterised the system using a combination of photometry from WASP-South and TRAPPIST-South, and spectra from CORALIE (around the orbit) and HARPS (through the transit). We find the planet's orbit to be nearly aligned with its star's spin. From a detection of the Rossiter-McLaughlin effect, we measure a projected stellar obliquity of λ=19±6\lambda = -19 \pm 6^\circ. From line-profile tomography of the same spectra, we measure λ=11±5\lambda = -11 \pm 5^\circ. We find the planet to have a low density (MPM_{\rm P} = 0.67 ±\pm 0.09 MJupM_{\rm Jup}, RPR_{\rm P} = 1.54 ±\pm 0.06 RJupR_{\rm Jup}), which, along with its moderately bright host star, makes it a good target for transmission spectroscopy. We find a lower stellar mass (MM_* = 1.30±0.071.30 \pm 0.07 MM_\odot) than reported by the NGTS team (MM_* = 1.64±0.211.64 \pm 0.21 MM_\odot), though the difference is only 1.51.5 σ\sigma.Comment: Submitted to AJ. 9 pages, 6 figures, 5 table

    Information sharing and credit : firm-level evidence from transition countries

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    We investigate whether information sharing among banks has affected credit market performance in the transition countries of Eastern Europe and the former Soviet Union, using a large sample of firm-level data. Our estimates show that information sharing is associated with improved availability and lower cost of credit to firms. This correlation is stronger for opaque firms than transparent ones and stronger in countries with weak legal environments than in those with strong legal environments. In cross-sectional estimates, we control for variation in country-level aggregate variables that may affect credit, by examining the differential impact of information sharing across firm types. In panel estimates, we also control for the presence of unobserved heterogeneity at the firm level, as well as for changes in macroeconomic variables and the legal environment

    Magnetic topology and surface differential rotation on the K1 subgiant of the RS CVn system HR 1099

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    We present here spectropolarimetric observations of the RS CVn system HR 1099 (V711 Tau) secured from 1998 February to 2002 January with the spectropolarimeter MuSiCoS at the Telescope Bernard Lyot (Observatoire du Pic du Midi, France). We apply Zeeman-Doppler Imaging and reconstruct brightness and magnetic surface topologies of the K1 primary subgiant of the system, at five different epochs. We confirm the presence of large, axisymmetric regions where the magnetic field is mainly azimuthal, providing further support to the hypothesis that dynamo processes may be distributed throughout the whole convective zone in this star. We study the short-term evolution of surface structures from a comparison of our images with observations secured at close-by epochs by Donati et al. (2003) at the Anglo-Australian Telescope. We conclude that the small-scale brightness and magnetic patterns undergo major changes within a timescale of 4 to 6 weeks, while the largest structures remain stable over several years. We report the detection of a weak surface differential rotation (both from brightness and magnetic tracers) indicating that the equator rotates faster than the pole with a difference in rotation rate between the pole and the equator about 4 times smaller than that of the Sun. This result suggests that tidal forces also impact the global dynamic equilibrium of convective zones in cool active stars.Comment: accepted by MNRA

    Methylated DNA Immunoprecipitation

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    The identification of DNA methylation patterns is a common procedure in the study of epigenetics, as methylation is known to have significant effects on gene expression, and is involved with normal development as well as disease 1-4. Thus, the ability to discriminate between methylated DNA and non-methylated DNA is essential for generating methylation profiles for such studies. Methylated DNA immunoprecipitation (MeDIP) is an efficient technique for the extraction of methylated DNA from a sample of interest 5-7. A sample of as little as 200 ng of DNA is sufficient for the antibody, or immunoprecipitation (IP), reaction. DNA is sonicated into fragments ranging in size from 300-1000 bp, and is divided into immunoprecipitated (IP) and input (IN) portions. IP DNA is subsequently heat denatured and then incubated with anti-5'mC, allowing the monoclonal antibody to bind methylated DNA. After this, magnetic beads containing a secondary antibody with affinity for the primary antibody are added, and incubated. These bead-linked antibodies will bind the monoclonal antibody used in the first step. DNA bound to the antibody complex (methylated DNA) is separated from the rest of the DNA by using a magnet to pull the complexes out of solution. Several washes using IP buffer are then performed to remove the unbound, non-methylated DNA. The methylated DNA/antibody complexes are then digested with Proteinase K to digest the antibodies leaving only the methylated DNA intact. The enriched DNA is purified by phenol:chloroform extraction to remove the protein matter and then precipitated and resuspended in water for later use. PCR techniques can be used to validate the efficiency of the MeDIP procedure by analyzing the amplification products of IP and IN DNA for regions known to lack and known to contain methylated sequences. The purified methylated DNA can then be used for locus-specific (PCR) or genome-wide (microarray and sequencing) methylation studies, and is particularly useful when applied in conjunction with other research tools such as gene expression profiling and array comparative genome hybridization (CGH) 8. Further investigation into DNA methylation will lead to the discovery of new epigenetic targets, which in turn, may be useful in developing new therapeutic or prognostic research tools for diseases such as cancer that are characterized by aberrantly methylated DNA 2, 4, 9-11

    WASP-157b, a Transiting Hot Jupiter Observed with K2

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    We announce the discovery of the transiting hot Jupiter WASP-157b in a 3.95-d orbit around a V = 12.9 G2 main-sequence star. This moderately inflated planet has a Saturn-like density with a mass of 0.57±0.100.57 \pm 0.10 MJup_{\rm Jup} and a radius of 1.06±0.051.06 \pm 0.05 RJup_{\rm Jup}. We do not detect any rotational or phase-curve modulations, nor the secondary eclipse, with conservative semi-amplitude upper limits of 250 and 20 ppm, respectively.Comment: 6 pages, 5 figures and 4 tables. Accepted for publication in PAS

    WASP-189b: an ultra-hot Jupiter transiting the bright A star HR 5599 in a polar orbit

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    We report the discovery of WASP-189b: an ultra-hot Jupiter in a 2.72-d transiting orbit around the V=6.6V = 6.6 A star WASP-189 (HR 5599). We detected periodic dimmings in the star's lightcurve, first with the WASP-South survey facility then with the TRAPPIST-South telescope. We confirmed that a planet is the cause of those dimmings via line-profile tomography and radial-velocity measurements using the HARPS and CORALIE spectrographs. Those reveal WASP-189b to be an ultra-hot Jupiter (MPM_{\rm P} = 2.13 ±\pm 0.28 MJupM_{\rm Jup}; RPR_{\rm P} = 1.374 ±\pm 0.082 RJupR_{\rm Jup}) in a polar orbit (λ=89.3±1.4\lambda = 89.3 \pm 1.4^\circ; Ψ=90.0±5.8\Psi = 90.0 \pm 5.8^\circ) around a rapidly rotating A6IV-V star (TeffT_{\rm eff} = 8000 ±\pm 100 K; vsiniv_* \sin i_* \approx 100 km\, s1^{-1}). We calculate a predicted equilibrium temperature of TeqlT_{\rm eql} = 2641 ±\pm 34 K, assuming zero albedo and efficient redistribution, which is the third hottest for the known exoplanets. WASP-189 is the brightest known host of a transiting hot Jupiter and the third-brightest known host of any transiting exoplanet. We note that of the eight hot-Jupiter systems with TeffT_{\rm eff} >> 7000 K, seven have strongly misaligned orbits, and two of the three systems with TeffT_{\rm eff} \geq 8000 K have polar orbits (the third is aligned).Comment: Submitted to MNRAS. 10 pages, 9 figures, 3 table
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