62,038 research outputs found

    Dwarf nova oscillations and quasi-periodic oscillations in cataclysmic variables - VII. OY Carinae and oscillations in dwarf novae in quiescence

    Full text link
    We have observed dwarf nova oscillations (DNOs) in OY Car during outburst, down through decline and beyond; its behaviour is similar to what we have previously seen in VW Hyi, making it only the second dwarf nova to have DNOs late in outburst that continue well into quiescence. There are also occasional examples of DNOs in deep quiescence, well away from outburst - they have properties similar to those during outburst, indicating similar physical causes and structures. We discuss the occurrence of DNOs in other dwarf novae and conclude that DNOs during quiescence are more common than often supposed and exhibit properties similar to those seen in outburst.Comment: Accepted for publication in MNRAS; paper contains 11 figures and 2 tables. This paper has become paper VII in the serie

    Dwarf nova oscillations and quasi-periodic oscillations in cataclysmic variables -- VI. Spin rates, propellering, and coherence

    Full text link
    We examine published observations of dwarf nova oscillations (DNOs) on the rise and decline of outbursts and show that their rates of change are in reasonable agreement with those predicted from the magnetic accretion model. We find evidence for propellering in the late stages of outburst of several dwarf novae, as shown by reductions in EUVE fluxes and from rapid increases of the DNO periods. Reanalysis of DNOs observed in TY PsA, which had particularly large amplitudes, shows that the apparent loss of coherence during late decline is better described as a regular switching between two nearby periods. It is partly this and the rapid deceleration in some systems that make the DNOs harder to detect. We suggest that the 28.95 s periodicity in WZ Sge, which has long been a puzzle, is caused by heated regions in the disc, just beyond the corotation radius, which are a consequence of magnetic coupling between the primary and gas in the accretion disc. This leads to a possible new interpretation of the `longer period DNOs' (lpDNOs) commonly observed in dwarf novae and nova-like variables.Comment: 9 pages, 3 figure, accepted for publication in MNRA

    Author Identifiers in Scholarly Repositories

    Get PDF
    Bibliometric and usage-based analyses and tools highlight the value of information about scholarship contained within the network of authors, articles and usage data. Less progress has been made on populating and using the author side of this network than the article side, in part because of the difficulty of unambiguously identifying authors. I briefly review a sample of author identifier schemes, and consider use in scholarly repositories. I then describe preliminary work at arXiv to implement public author identifiers, services based on them, and plans to make this information useful beyond the boundaries of arXiv.Comment: 10 pages. Based on a presentation given at Open Repositories 200

    High Speed photometry of faint Cataclysmic Variables: I. V359 Cen, XZ Eri, HY Lup, V351 Pup, V630 Sgr, YY Tel, CQ Vel, CE-315

    Get PDF
    The first results of a photometric survey of faint Cataclysmic Variables are presented. V359 Cen is an SU UMa star with a period of 112 min. Even though observed at quiescence, the mass transfer rate in this old nova may be sufficiently high that in such a short period system (with its implied small mass ratio) the disc may be excited into an elliptical shape with the result that the observed brightness modulation gives a superhump period rather than an orbital period. XZ Eri is an eclipsing dwarf nova with an orbital period (P(orb)) of 88.1 min. HY Lup has only slight variability. V351 Pup, the remnant of Nova Puppis 1991, has P(orb) = 2.837 h and a light curve that strongly resembles that of the magnetic Nova Cyg 1975. V630 Sgr is the first nova remnant that has both positive superhumps (P(sh) = 2.980 h) and eclipses (P(orb) = 2.831 h). The YY Tel identification is somewhat uncertain. The correct identification for CQ Vel is provided from discovery of its flickering activity. The light curve of CE-315, a recently discovered AM CVn star, shows similarities to that of GP Com, with no apparent orbital modulation.Comment: 8 pages, 12 figures, accepted for publication in MNRA

    Longevity Genes: From Primitive Organisms to Humans

    Get PDF
    A variety of lines of evidence indicate that aging and longevity are subject to genetic regulation, but until fairly recently the identity of these genes was unknown. This has changed dramatically over the last ten years. Recommends several courses of carrying research on "longevity genes" to humans

    Style over Substance?: Fashion, Spectacle and Narrative in Contemporary US Television

    Get PDF
    Previous scholarship on fashion and film has debated the aesthetic role played by onscreen costume. Yet there has been little exploration of fashion and its use in television. Existing work on fashion in onscreen media has approached the debate from a textual perspective, and such work has been informed by the longstanding assumption that fashion acts primarily as ‘spectacle’, disrupting the economy of narrative flow. This article seeks to challenge this assumption by arguing that previous work is limited by the wider conceptual and methodological problems of purely textual approaches. Using CW’s Gossip Girl as a case study, the author suggests that a mixed method approach to the study of costume (using both textual analysis and reception studies) provides a more productive foundation upon which to begin to examine the function of onscreen fashion in contemporary US television. Such an approach may have particular importance in understanding how costume in ‘fashion-forward’ television can be best understood if one steps beyond the text to explore the sense-making of viewers, the intentions of costume designers and the relationship between viewers, the shows and the wider fashion market

    Eprints and the Open Archives Initiative

    Full text link
    The Open Archives Initiative (OAI) was created as a practical way to promote interoperability between eprint repositories. Although the scope of the OAI has been broadened, eprint repositories still represent a significant fraction of OAI data providers. In this article I present a brief survey of OAI eprint repositories, and of services using metadata harvested from eprint repositories using the OAI protocol for metadata harvesting (OAI-PMH). I then discuss several situations where metadata harvesting may be used to further improve the utility of eprint archives as a component of the scholarly communication infrastructure.Comment: 13 page

    Protecting Fundamental Labor Rights: Lessons from Canada for the United States

    Get PDF
    This paper examines the decline in unionization in the United States that began to occur in about 1960. While various explanations have been put forward to explain this -- with many focusing on some form of structural changes to the economy or to the workforce, usually related to globalization or technological progress -- this paper focuses on the role that employer opposition to unions has played, together with relatively weak labor law. In order to fully flesh out the experience of the United States, it looks to the experience of Canada as the country most similar to it

    Exposing and harvesting metadata using the OAI metadata harvesting protocol: A tutorial

    Get PDF
    In this article I outline the ideas behind the Open Archives Initiative metadata harvesting protocol (OAIMH), and attempt to clarify some common misconceptions. I then consider how the OAIMH protocol can be used to expose and harvest metadata. Perl code examples are given as practical illustration.Comment: 13 pages, 1 figure. Example programs included (download source). HEPLW version (HTML) available online at http://library.cern.ch/HEPLW/4/papers/3
    • …
    corecore