5,931 research outputs found

    Southern Hemisphere automated supernova search

    Get PDF
    The Perth Astronomy Research Group has developed an automated supernova search program, using the 61 cm Perth–Lowell reflecting telescope at Perth Observatory in Western Australia, equipped with a CCD camera. The system is currently capable of observing about 15 objects per hour, using 3 min exposures, and has a detection threshold of 18th–19th magnitude. The entire system has been constructed using low‐cost IBM‐compatible computers. Two original discoveries (SN 1993K, SN 1994R) have so far been made during automated search runs. This paper describes the hardware and software used for the supernova search program, and shows some preliminary results from the search system

    The Infrared Massive Stellar Content of M83

    Full text link
    We present an analysis of archival Spitzer images and new ground-based and Hubble Space Telescope (HST) near-infrared (IR) and optical images of the field of M83 with the goal of identifying rare, dusty, evolved massive stars. We present point source catalogs consisting of 3778 objects from SpitzerSpitzer Infrared Array Camera (IRAC) Band 1 (3.6 ÎŒ\mum) and Band 2 (4.5 ÎŒ\mum), and 975 objects identified in Magellan 6.5m FourStar near-IR JJ and KsK_{\rm s} images. A combined catalog of coordinate matched near- and mid-IR point sources yields 221 objects in the field of M83. Using this photometry we identify 185 massive evolved stellar candidates based on their location in color-magnitude and color-color diagrams. We estimate the background contamination to our stellar candidate lists and further classify candidates based on their appearance in HSTHST Wide Field Camera 3 (WFC3) observations of M83. We find 49 strong candidates for massive stars which are very promising objects for spectroscopic follow-up. Based on their location in a B−VB-V versus V−IV-I diagram, we expect at least 24, or roughly 50%, to be confirmed as red supergiants.Comment: 32 pages, 23 figures, accepted for publication in A&

    Assurance Services as a Substitute for Law in Global Commerce

    Get PDF
    In this article we examine the rapid emergence and expansion of a private-sector compliance and enforcement infrastructure that we believe may increasingly be providing a substitute for public and legal regulatory infrastructure in global commerce, especially in developing countries where rule of law is weak and court systems are absent or inadequate. This infrastructure is provided by a proliferation of performance codes and standards, and a rapidly-growing global army of privately-trained and authorized inspectors and certifiers that we call the third-party assurance industry. The growth in the third party assurance business has been phenomenal in the last decade. The business first developed to facilitate making and carrying out private contracts, but in recent years, assurance services are being deployed for purposes that are more appropriately seen as regulatory in nature. Third-party assurance may thus be providing a new institutional structure through which private commercial exchange is being harnessed and regulated for essentially public purposes

    In the beginning: Role of autonomy support on the motivation, mental health and intentions of participants entering an exercise referral scheme

    Get PDF
    Self-determination theory (Deci & Ryan, 2000, Intrinsic motivation and self-determination in human behaviour. New York: Plenum Publishing) highlights the impact autonomy supportive environments can have on exercise motivation and positive health outcomes. Yet little is known about whether differential effects occur as a function of which significant other is providing this support. Further, no research has examined the relationship between motivation and the social environment with participants’ mental health and intentions to be physically active before entering an exercise intervention. Study participants were 347 British adults who were about to start an exercise referral scheme. Regression analyses revealed that the effects of autonomy support on mental health and physical activity intentions differed as a function of who provided the support (offspring, partner or physician), with the offspring having the weakest effects. A structural model was supported, indicating that autonomy support and more autonomous regulations led to more positive mental health outcomes and stronger intentions to be physically active. Knowledge of the social environmental and personal motivation of those about to commence an exercise programme can provide important insights for professionals supporting such efforts

    Creating citizen-consumers? Public service reform and (un)willing selves

    No full text
    About the book: Postmodern theories heralded the "death of the subject", and thereby deeply contested our intuition that we are free and willing selves. In recent times, the (free) will has come under attack yet again. Findings from the neuro- and cognitive sciences claim the concept of will to be scientifically untenable, specifying that it is our brain rather than our 'self' which decides what we want to do. In spite of these challenges however, the willing self has come to take centre stage in our society: juridical and moral practices ascribing guilt, or the organization of everyday life attributing responsibilities, for instance, can hardly be understood without taking recourse to the willing subject. In this vein, the authors address topics such as the genealogy of the concept of willing selves, the discourse on agency in neuroscience and sociology, the political debate on volition within neoliberal and neoconservative regimes, approaches toward novel forms of relational responsibility as well as moral evaluations in conceptualizing autonomy

    Analytical characteristics and comparative evaluation of Aptima HCV quant Dx assay with the Abbott RealTime HCV assay and Roche COBAS AmpliPrep/COBAS TaqMan HCV quantitative test v2.0

    Get PDF
    Abstract Background The Aptima HCV Quant Dx assay (Aptima assay) is a fully automated quantitative assay on the Panther¼ system. This assay is intended for confirmation of diagnosis and monitoring of HCV RNA in plasma and serum specimens. The purpose of the testing described in this paper was to evaluate the performance of the Aptima assay. Methods The analytical sensitivity, analytical specificity, precision, and linearity of the Aptima assay were assessed. The performance of the Aptima assay was compared to two commercially available HCV assays; the Abbott RealTime HCV assay (Abbott assay, Abbott Labs Illinois, USA) and the Roche COBAS Ampliprep/COBAS Taqman HCV Quantitative Test v2.0 (Roche Assay, Roche Molecular Systems, Pleasanton CA, USA). The 95% Lower Limit of Detection (LoD) of the assay was determined from dilutions of the 2nd HCV WHO International Standard (NIBSC 96/798 genotype 1) and HCV positive clinical specimens in HCV negative human plasma and serum. Probit analysis was performed to generate the 95% predicted detection limits. The Lower Limit of Quantitation (LLoQ) was established for each genotype by diluting clinical specimens and the 2nd HCV WHO International Standard (NIBSC 96/798 genotype 1) in HCV negative human plasma and serum. Specificity was determined using 200 fresh and 536 frozen HCV RNA negative clinical specimens including 370 plasma specimens and 366 serum specimens. Linearity for genotypes 1 to 6 was established by diluting armored RNA or HCV positive clinical specimens in HCV negative serum or plasma from 8.08 log IU/mL to below 1 log IU/mL. Precision was tested using a 10 member panel made by diluting HCV positive clinical specimens or spiking armored RNA into HCV negative plasma and serum. A method comparison was conducted against the Abbott assay using 1058 clinical specimens and against the Roche assay using 608 clinical specimens from HCV infected patients. In addition, agreement between the Roche assay and the Aptima assay using specimens with low HCV concentrations (</= 25 IU/mL by Roche) was tested using 107 clinical specimens. Results The 95% LoD was 5.1 IU/mL or lower for serum and 4.8 IU/mL or lower for plasma depending on the HCV genotype. The LLoQ for the assay was 10 IU/mL. Specificity was 100% with 95% confidence intervals of 99.6 to 100% for serum and plasma data combined. The assay demonstrated good linearity across the range for all genotypes. The Precision as estimated by the standard deviation (sd) was 0.17 log or lower across the range of the assay for both serum and plasma. HCV viral load results were compared using the Aptima assay and the Abbott assay giving a slope of 1.06, an intercept of 0.08 and an R2 of 0.98. HCV viral load results were compared for the Aptima and Roche assays giving a slope of 1.05, an intercept of −0.12 and an R2 of 0.96. Positive and negative agreement for the Aptima assay vs the Roche assay was 89% for low level specimens. Conclusion The Aptima assay is a highly sensitive and specific assay. The assay gave comparable HCV viral load results when compared to the Abbott and Roche assays. The performance of the Aptima assay makes it an excellent candidate for the detection and monitoring of HCV

    The Chandra Local Volume Survey: The X-ray Point Source Catalog of NGC 300

    Full text link
    We present the source catalog of a new Chandra ACIS-I observation of NGC 300 obtained as part of the Chandra Local Volume Survey. Our 63 ks exposure covers ~88% of the D25 isophote (R~6.3 kpc) and yields a catalog of 95 X-ray point sources detected at high significance to a limiting unabsorbed 0.35-8 keV luminosity of ~10^36 erg s^-1. Sources were cross-correlated with a previous XMM-Newton catalog, and we find 75 "X-ray transient candidate" sources that were detected by one observatory, but not the other. We derive an X-ray scale length of 1.7+/-0.2 kpc and a recent star formation rate of 0.12 Msun yr^-1, in excellent agreement with optical observations. Deep, multi-color imaging from the Hubble Space Telescope, covering ~32% of our Chandra field, was used to search for optical counterparts to the X-ray sources, and we have developed a new source classification scheme to determine which sources are likely X-ray binaries, supernova remnants, and background AGN candidates. Finally, we present the X-ray luminosity functions (XLFs) at different X-ray energies, and we find the total NGC 300 X-ray point source population to be consistent with other late-type galaxies hosting young stellar populations (<50 Myr). We find XLF of sources associated with older stellar populations has a steeper slope than the XLF of X-ray sources coinciding with young stellar populations, consistent with theoretical predictions.Comment: 23 pages, 13 figures. Accepted to Ap

    Conditional citizens? welfare rights and responsibilities in the late 1990s

    Get PDF
    In Britain the relationship between welfare rights and responsibilities has undergone change. A new welfare 'consensus' that emphasizes a citizen ship centred on notions of duty rather than rights has been built. This has allowed the state to reduce its role as a provider of welfare and also defend a position in which the welfare rights of some citizens are increas ingly conditional on those individuals meeting compulsory responsibili ties or duties. This concentration on individual responsibility/duty has undermined the welfare rights of some of the poorest members of society. Three levels of debate are considered within the article: academic, pol itical and 'grassroots'. The latter is included in an attempt to allow some 'bottom up' views into what is largely a debate dominated by social sci entists and politicians

    Exact steady state solution of the Boltzmann equation: A driven 1-D inelastic Maxwell gas

    Full text link
    The exact nonequilibrium steady state solution of the nonlinear Boltzmann equation for a driven inelastic Maxwell model was obtained by Ben-Naim and Krapivsky [Phys. Rev. E 61, R5 (2000)] in the form of an infinite product for the Fourier transform of the distribution function f(c)f(c). In this paper we have inverted the Fourier transform to express f(c)f(c) in the form of an infinite series of exponentially decaying terms. The dominant high energy tail is exponential, f(c)≃A0exp⁥(−a∣c∣)f(c)\simeq A_0\exp(-a|c|), where a≡2/1−α2a\equiv 2/\sqrt{1-\alpha^2} and the amplitude A0A_0 is given in terms of a converging sum. This is explicitly shown in the totally inelastic limit (α→0\alpha\to 0) and in the quasi-elastic limit (α→1\alpha\to 1). In the latter case, the distribution is dominated by a Maxwellian for a very wide range of velocities, but a crossover from a Maxwellian to an exponential high energy tail exists for velocities ∣c−c0âˆŁâˆŒ1/q|c-c_0|\sim 1/\sqrt{q} around a crossover velocity c0≃ln⁥q−1/qc_0\simeq \ln q^{-1}/\sqrt{q}, where q≡(1−α)/2â‰Ș1q\equiv (1-\alpha)/2\ll 1. In this crossover region the distribution function is extremely small, ln⁥f(c0)≃q−1ln⁥q\ln f(c_0)\simeq q^{-1}\ln q.Comment: 11 pages, 4 figures; a table and a few references added; to be published in PR
    • 

    corecore