1,896 research outputs found

    Warm HCN, C2H2, and CO in the disk of GV Tau

    Get PDF
    We present the first high-resolution, ground-based observations of HCN and C2H2 toward the T Tauri binary star system GV Tau. We detected strong absorption due to HCN nu_3 and weak C2H2 (nu_3 and nu_2 + (nu_4 + nu_5)^0_+) absorption toward the primary (GV Tau S) but not the infrared companion. We also report CO column densities and rotational temperatures, and present abundances relative to CO of HCN/CO ~0.6% and C2H2/CO ~1.2% and an upper limit for CH4/CO < 0.37% toward GV Tau S. Neither HCN nor C2H2 were detected toward the infrared companion and results suggest that abundances may differ between the two sources.Comment: 23 pages, 6 figures, accepted by Ap

    Botulinum toxin injections as a method for chemically denervating skeletal muscle to test functional hypotheses: a pilot study in Lepomis cyanellus

    Get PDF
    In this study, we demonstrate that botulinum toxin can be used to chemically denervate muscles to test functional hypotheses. We injected research-grade type A botulinum toxin complex into pectoral fin abductors (abductor superficialis) of green sunfish (Lepomis cyanellus) to determine whether chemical denervation would eliminate the ability of a particular muscle to contribute to overall pectoral fin movements. Reduction of target muscle activity occurred within 8 d of the injection, and paralysis was confirmed using electromyography. No paralysis was seen in the adjacent muscles (abductor profundus) or in positive controls (saline injections). Paralysis occurred more slowly and at lower doses than previously documented for mammals. However, botulinum toxin complex (500 kDa) was used here, whereas previous studies have used purified toxin (150 kDa). Therefore, differences in physiological responses between fish and mammals cannot yet be distinguished from differences caused by the toxin type. However, we note that the toxin complex is less likely to diffuse across muscle fascia (because it is large), which should minimize paralytic effects on adjacent muscles. We suggest that botulinum toxin holds great promise as a chemical denervation agent in functional studies of animal locomotion and feeding behaviors

    Post-Outburst Observations of V1647 Ori: Detection of a Brief Warm, Molecular Outflow

    Get PDF
    We present new observations of the fundamental ro-vibrational CO spectrum of V1647 Ori, the young star whose recent outburst illuminated McNeil's Nebula. Previous spectra, acquired during outburst in 2004 February and July, had shown the CO emission lines to be broad and centrally peaked-similar to the CO spectrum of a typical classical T Tauri star. In this paper, we present CO spectra acquired shortly after the luminosity of the source returned to its pre-outburst level (2006 February) and roughly one year later (2006 December and 2007 February). The spectrum taken in 2006 February revealed blue-shifted CO absorption lines superimposed on the previously observed CO emission lines. The projected velocity, column density, and temperature of this outflowing gas was 30 km/s, 3^{+2}_{-1}E18 cm^{-2$, and 700^{+300}_{-100} K, respectively. The absorption lines were not observed in the 2006 December and 2007 February data, and so their strengths must have decreased in the interim by a factor of 9 or more. We discuss three mechanisms that could give rise to this unusual outflow.Comment: 14 pages, 2 figures, accepted for publication in ApJ

    Automation of flow injection gas diffusion-ion chromatography for the nanomolar determination of methylamines and ammonia in seawater and atmospheric samples

    Get PDF
    The automation and improved design and performance of Flow Injection Gas Diffusion-Ion Chromatography (FIGD-IC), a novel technique for the simultaneous analysis of trace ammonia (NH3) and methylamines (MAs) in aqueous media, is presented. Automated Flow Injection Gas Diffusion (FIGD) promotes the selective transmembrane diffusion of MAs and NH3 from aqueous sample under strongly alkaline (pH > 12, NaOH), chelated (EDTA) conditions into a recycled acidic acceptor stream. The acceptor is then injected onto an ion chromatograph where NH3 and the MAs are fully resolved as their cations and detected conductimetrically. A versatile PC interfaced control unit and data capture unit (DCU) are employed in series to direct the selonoid valve switching sequence, IC operation and collection of data. Automation, together with other modifications improved both linearily (R2 > 0.99 MAs 0-100 nM, NH3 0-1000 nM) and precision (<8%) of FIGD-IC at nanomolar concentrations, compared with the manual procedure. The system was successfully applied to the determination of MAs and NH3 in seawater and in trapped particulate and gaseous atmospheric samples during an oceanographic research cruise

    Logics, rhetoric and 'the blob': populist logic in the Conservative reforms to English schooling

    Get PDF
    A lot has been written about the lasting implications of the Conservative reforms to English schooling, particularly changes made by Michael Gove as Education Secretary (2010ā€“2014). There is a lot less work, however, on studying the role that language, strategy and the broader political framework played in the process of instituting and winning consent for these reforms. Studying these factors is important for ensuring that any changes to education and schooling are not read in isolation from their political context. Speeches particularly capture moments where intellectual and strategic political traditions meet, helping us to form a richer understanding of the motives behind specific reform goals and where they fit into a political landscape. This article analyses speeches and policy documents from prominent politicians who led the Conservative education agenda between 2010ā€“2014 to illustrate how politicians mobilised a deliberate populist strategy and argumentation to achieve specific educational goals, but which have had broader social and political implications. Concepts from interpretive political studies are used to develop a case analysis of changes to teacher training provision and curriculum reform, illustrating how politicians constructed a frontier between ā€˜the peopleā€™ (commonly teachers or parents) and an illegitimate ā€˜eliteā€™ (an educational establishment) that opposed change. This antiā€elite populist rhetoric, arguably first tested in the Department for Education, has now become instituted more widely in our current British politics

    Sensitivity of ferry services to the Western Isles of Scotland to changes in wave and wind climate

    Get PDF
    PublishedJournal ArticleThis is the final version of the article. Available from AMS via the DOI in this record.The roughness of the seas is rarely mentioned as a major factor in the economic or social welfare of a region. In this study, the relationship between the ocean wave climate and the economy of the Western Isles of Scotland is examined. This sparsely populated region has a high dependency on marine activities, and ferry services provide vital links between communities. The seas in the region are among the roughest in the world during autumn and winter, however, making maintenance of a reliable ferry service both difficult and expensive. A deterioration in wave and wind climate either in response to natural variability or as a regional response to anthropogenic climate change is possible. Satellite altimetry and gale-frequency data are used to analyze the contemporary response of wave and wind climate to the North Atlantic Oscillation (NAO). The sensitivity of wave climate to the NAO extends to ferry routes that are only partially sheltered and are exposed to ocean waves; thus, the reliability of ferry services is sensitive to NAO. Any deterioration of the wave climate will result in a disproportionately large increase in ferry-service disruption. The impacts associated with an unusually large storm event that affected the region in January 2005 are briefly explored to provide an insight into vulnerability to future storm events. Ā© 2013 American Meteorological Society.This research was largely supported by the Tyndall Centre for Climate Change Research project ā€œToward a vulnerability assessment for the UK coastlineā€ (IT 1.15)
    • ā€¦
    corecore