77 research outputs found

    Wasted Words?: Current Trends in Collection Development Policies

    Get PDF
    The transition to electronic resources and the changing role of the collection development librarian are having a tremendous impact on the manner by which libraries select and acquire new materials. The goal of this research project was to further elucidate the current trends of collection development policies in members of the Association of Research Libraries (ARL) as well as gauge current use and future efficacy. The survey was designed and sent to librarians responsible for collection development at university-affiliated ARL libraries in order to obtain a current picture of academic collection development policies, and how they are changing due to the abundance of electronic resources and new methods of data-driven acquisitions. The goals of the survey are to Measure the continued use of CD policies as major collection-building tools; Assess the frequency of updates to collection development policies; Determine the availability of collection development policies; Measure and compare the amount of time available to librarians to review and select new materials; Determine if print materials are being reviewed in new and innovative ways or if they receive the same assessment as electronically formatted materials; Measure the employment of data or patron-driven acquisition methods. The findings will require additional assessment, but the data does seem to indicate a time of change in the way academic libraries complete and assess their primary collection development activities. This survey was created, at least in part, with the hope of setting a starting point for continued evaluation and longitudinal measurement. If our survey participants are as actively helpful in future years, these dreams of cyclical assessment may well come to fruition

    Impulse control disorders in dopamine agonist-treated hyperprolactinemia: Prevalence and risk factors

    Get PDF
    Context: There are growing reports of dopamine agonist (DA)-induced impulse control disorders (ICDs) in hyperprolactinemic patients. However, the magnitude of this risk and predictive factors remain uncertain. Objective: To determine ICD prevalence and risk factors in DA-treated hyperprolactinemic patients compared to community controls. Design, Setting and Participants: Multicenter cross-sectional analysis of 113 patients and 99 healthy controls. Main Outcome Measures: Participants completed a neuropsychological questionnaire consisting of the Depression Anxiety Stress Scale (DASS21), Questionnaire for Impulsive-Compulsive Disorders in Parkinson’s disease (QUIP-S), Hypersexual Behavior Inventory (HBI), Hypersexual Behavior Consequences Scale and Social Desirability Response Set Scale. Demographic and clinical data were collated to determine ICD risk factors. Patients testing positive for an ICD were offered a semi-structured psychological interview. Results: Patients were more likely than controls to test positive by QUIP-S for any ICD (61.1 vs 42.4%, P=0.01), hypersexuality (22.1 vs 8.1%, P=0.009), compulsive buying (15.9 vs 6.1%, P=0.041) and punding (18.6 vs 6.1%, P=0.012), and by HBI for hypersexuality (8.0 vs 0.0%, P=0.004). Independent risk factors were male sex (OR 13.85), eugonadism (OR 7.85), Hardy’s tumor score, and psychiatric comorbidity (OR 6.86) for hypersexuality; and age (OR 0.95) for compulsive buying. DASS21 subset scores were higher in patients vs controls, and in patients with vs without different ICDs. Only 19/51 (37.3%) interviewed patients were aware of the relationship between DAs and ICDs before the study. Conclusions: DA therapy poses a high, previously underestimated risk of ICDs, especially in the form of hypersexuality in eugonadal men

    The TESS light curve of AI Phoenicis

    Get PDF
    Accurate masses and radii for normal stars derived from observations of detached eclipsing binary stars are of fundamental importance for testing stellar models and may be useful for calibrating free parameters in these model if the masses and radii are sufficiently precise and accurate. We aim to measure precise masses and radii for the stars in the bright eclipsing binary AI Phe, and to quantify the level of systematic error in these estimates. We use several different methods to model the TESS light curve of AI Phe combined with spectroscopic orbits from multiple sources to estimate precisely the stellar masses and radii together with robust error estimates. We find that the agreement between different methods for the light curve analysis is very good but some methods underestimate the errors on the model parameters. The semi-amplitudes of the spectroscopic orbits derived from spectra obtained with modern echelle spectrographs are consistent to within 0.1%. The masses of the stars in AI Phe are M1=1.1938±0.0008M⊙M_1 = 1.1938 \pm 0.0008 M_{\odot} and M2=1.2438±0.0008M⊙M_2 = 1.2438 \pm 0.0008M_{\odot}, and the radii are R1=1.8050±0.0022R⊙R_1 = 1.8050 \pm 0.0022 R_{\odot} and R2=2.9332±0.0023R⊙R_2 = 2.9332 \pm 0.0023 R_{\odot}. We conclude that it is possible to measure accurate masses and radii for stars in bright eclipsing binary stars to a precision of 0.2% or better using photometry from TESS and spectroscopy obtained with modern echelle spectrographs. We provide recommendations for publishing masses and radii of eclipsing binary stars at this level of precision

    Galaxy groups in the 2dFGRS: the group-finding algorithm and the 2PIGG catalogue

    Get PDF
    The construction of a catalogue of galaxy groups from the Two-degree Field Galaxy Redshift Survey (2dFGRS) is described. Groups are identified by means of a friends-of-friends percolation algorithm which has been thoroughly tested on mock versions of the 2dFGRS generated from cosmological N-body simulations. The tests suggest that the algorithm groups all galaxies that it should be grouping, with an additional 40 per cent of interlopers. About 55 per cent of the ∼190 000 galaxies considered are placed into groups containing at least two members of which ∼29 000 are found. Of these, ∼7000 contain at least four galaxies, and these groups have a median redshift of 0.11 and a median velocity dispersion of 260 km s−1. This 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) catalogue represents the largest available homogeneous sample of galaxy groups. It is publicly available on the World Wide We

    The 2dF Galaxy Redshift Survey: power-spectrum analysis of the final data set and cosmological implications

    Get PDF
    We present a power-spectrum analysis of the final 2dF Galaxy Redshift Survey (2dFGRS), employing a direct Fourier method. The sample used comprises 221 414 galaxies with measured redshifts. We investigate in detail the modelling of the sample selection, improving on previous treatments in a number of respects. A new angular mask is derived, based on revisions to the photometric calibration. The redshift selection function is determined by dividing the survey according to rest-frame colour, and deducing a self-consistent treatment of k-corrections and evolution for each population. The covariance matrix for the power-spectrum estimates is determined using two different approaches to the construction of mock surveys, which are used to demonstrate that the input cosmological model can be correctly recovered. We discuss in detail the possible differences between the galaxy and mass power spectra, and treat these using simulations, analytic models and a hybrid empirical approach. Based on these investigations, we are confident that the 2dFGRS power spectrum can be used to infer the matter content of the universe. On large scales, our estimated power spectrum shows evidence for the ‘baryon oscillations' that are predicted in cold dark matter (CDM) models. Fitting to a CDM model, assuming a primordial ns= 1 spectrum, h= 0.72 and negligible neutrino mass, the preferred parameters are Ωmh= 0.168 ± 0.016 and a baryon fraction Ωb/Ωm= 0.185 ± 0.046 (1σ errors). The value of Ωmh is 1σ lower than the 0.20 ± 0.03 in our 2001 analysis of the partially complete 2dFGRS. This shift is largely due to the signal from the newly sampled regions of space, rather than the refinements in the treatment of observational selection. This analysis therefore implies a density significantly below the standard Ωm= 0.3: in combination with cosmic microwave background (CMB) data from the Wilkinson Microwave Anisotropy Probe (WMAP), we infer Ωm= 0.231 ± 0.02

    Galaxy groups in the Two-degree Field Galaxy Redshift Survey: the luminous content of the groups

    Get PDF
    The Two-degree Field Galaxy Redshift Survey (2dFGRS) Percolation-Inferred Galaxy Group (2PIGG) catalogue of ∼29 000 objects is used to study the luminous content of galaxy systems of various sizes. Mock galaxy catalogues constructed from cosmological simulations are used to gauge the accuracy with which intrinsic group properties can be recovered. It is found that a Schechter function is a reasonable fit to the galaxy luminosity functions in groups of different mass in the real data, and that the characteristic luminosity L⋆ is slightly larger for more massive groups. However, the mock data show that the shape of the recovered luminosity function is expected to differ from the true shape, and this must be allowed for when interpreting the data. Luminosity function results are presented in both the bJ and rF wavebands. The variation of the halo mass-to-light ratio, ϒ, with group size is studied in both of these wavebands. A robust trend of increasing ϒ with increasing group luminosity is found in the 2PIGG data. Going from groups with bJ luminosities equal to 1010h−2 L⊙ to those 100 times more luminous, the typical bJ-band mass-to-light ratio increases by a factor of 5, whereas the rF-band mass-to-light ratio grows by a factor of 3.5. These trends agree well with the predictions of the simulations which also predict a minimum in the mass-to-light ratio on a scale roughly corresponding to the Local Group. The data indicate that if such a minimum exists, then it must occur at L≲ 1010h−2 L⊙, below the range accurately probed by the 2PIGG catalogue. According to the mock data, the bJ mass-to-light ratios of the largest groups are expected to be approximately 1.1 times the global value. Assuming that this correction applies to the real data, the mean bJ luminosity density of the Universe yields an estimate of Ωm= 0.26 ± 0.03 (statistical error only). Various possible sources of systematic error are considered, with the conclusion that these could affect the estimate of Ωm by a few tens of per cen

    Measuring the 2D baryon acoustic oscillation signal of galaxies in WiggleZ: Cosmological constraints

    Get PDF
    We present results from the 2D anisotropic baryon acoustic oscillation (BAO) signal present in the final data set from the WiggleZ Dark Energy Survey. We analyse the WiggleZ data in two ways: first using the full shape of the 2D correlation function and secondly focusing only on the position of the BAO peak in the reconstructed data set. When fitting for the full shape of the 2D correlation function we use a multipole expansion to compare with theory. When we use the reconstructed data we marginalize over the shape and just measure the position of the BAO peak, analysing the data in wedges separating the signal along the line of sight from that parallel to the line of sight. We verify our method with mock data and find the results to be free of bias or systematic offsets. We also redo the pre-reconstruction angle-averaged (1D) WiggleZ BAO analysis with an improved covariance and present an updated result. The final results are presented in the form of Ωc h2, H(z), and DA(z) for three redshift bins with effective redshifts z=0.44, 0.60, and 0.73.Within these bins and methodologies, we recover constraints between 5 and 22 per cent error. Our cosmological constraints are consistent with flat ΛCDM cosmology and agree with results from the Baryon Oscillation Spectroscopic Surve

    The 2dF Galaxy Redshift Survey: the clustering of galaxy groups

    Get PDF
    We measure the clustering of galaxy groups in the 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) catalogue. The 2PIGG sample has 28 877 groups with at least two members. The clustering amplitude of the full 2PIGG catalogue is weaker than that of 2dFGRS galaxies, in agreement with theoretical predictions. We have subdivided the 2PIGG catalogue into samples that span a factor of ≈ 25 in median total luminosity. Our correlation function measurements span an unprecedented range of clustering strengths, connecting the regimes probed by groups fainter than L* galaxies and rich clusters. There is a steady increase in clustering strength with group luminosity; the most luminous groups are 10 times more strongly clustered than the full 2PIGG catalogue. We demonstrate that the 2PIGG results are in very good agreement with the clustering of groups expected in the ΛCDM mode

    The WiggleZ Dark Energy Survey: final data release and the metallicity of UV-luminous galaxies

    Get PDF
    The WiggleZ Dark Energy Survey measured the redshifts of over 200 000 ultraviolet (UV)- selected (NUV < 22.8 mag) galaxies on the Anglo-Australian Telescope. The survey detected the baryon acoustic oscillation signal in the large-scale distribution of galaxies over the redshift range 0.2 < z < 1.0, confirming the acceleration of the expansion of the Universe and measuring the rate of structure growth within it. Here, we present the final data release of the survey: a catalogue of 225 415 galaxies and individual files of the galaxy spectra. We analyse the emission-line properties of these UV-luminous Lyman-break galaxies by stacking the spectra in bins of luminosity, redshift, and stellar mass. The most luminous (-25 mag < MFUV < -22 mag) galaxies have very broad Hβ emission from active nuclei, as well as a broad second component to the [OIII] (495.9 nm, 500.7 nm) doublet lines that is blueshifted by 100 km s-1, indicating the presence of gas outflows in these galaxies. The composite spectra allow us to detect and measure the temperature-sensitive [O III] (436.3 nm) line and obtain metallicities using the direct method. The metallicities of intermediate stellar mass (8.8 < log (M*/M⊙) < 10)WiggleZ galaxies are consistent with normal emission-line galaxies at the samemasses. In contrast, the metallicities of high stellarmass (10 < log (M*/M⊙) < 12) WiggleZ galaxies are significantly lower than for normal emission-line galaxies at the same masses. This is not an effect of evolution as the metallicities do not vary with redshift; it is most likely a property specific to the extremely UV-luminous WiggleZ galaxies
    • …
    corecore