3,423 research outputs found

    Sulphur abundances in disk stars as determined from the forbidden 10821 A [SI] line

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    Aims: In this paper we aim to study the chemical evolution of sulphur in the galactic disk, using a new optimal abundance indicator: the [SI] line at 10821 A. Similar to the optimal oxygen indicators, the [OI] lines, the [SI] line has the virtues of being less sensitive to the assumed temperatures of the stars investigated and of likely being less prone to non-LTE effects than other tracers. Methods: High-resolution, near-infrared spectra of the [SI] line are recorded using the Phoenix spectrometer on the Gemini South telescope. The analysis is based on 1D, LTE model atmospheres using a homogeneous set of stellar parameters. Results: The 10821 A [SI] line is suitable for an abundance analysis of disk stars, and the sulphur abundances derived from it are consistent with abundances derived from other tracers. We corroborate that, for disk stars, the trend of sulphur-to-iron ratios with metallicity is similar to that found for other alpha elements, supporting the idea of a common nucleosynthetic origin.Comment: Accepted for publication in A&A Letter

    Occupational closure in nursing work reconsidered: UK health care support workers and assistant practitioners: a focus group study

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    In healthcare, occupational groups have adopted tactics to maintain autonomy and control over their areas of work. Witz described a credentialist approach to occupational closure adopted by nursing in the United Kingdom during the 19th and early 20th centuries. However, the recent advancement of assistant, ‘non-qualified’ workers by governments and managers forms part of a reconfiguration of traditional professional work. This research used focus groups with three cohorts of healthcare support workers undertaking assistant practitioner training at a London university from 2011-13 (6 groups, n=59). The aim was to examine how these workers positioned themselves as professionals and accounted for professional boundaries. A thematic analysis revealed a complex situation in which participants were divided between articulating an acceptance of a subordinate role within traditional occupational boundaries and a usurpatory stance towards these boundaries. Participants had usually been handpicked by managers and some were ambitious and confident in their abilities. Many aspired to train to be nurses claiming that they will gain recognition that they do not currently get but which they deserve. Their scope of practice is based upon their managers’ or supervisors’ perception of their individual aptitude rather than on a credentialist claim. They ‘usurp’ nurses claim to be the healthcare worker with privileged access to patients, saying they have taken over what nursing has considered its core work, while nurses abandon it for largely administrative roles. We conclude that the participants are the not unwilling agents of a managerially led project to reshape the workforce that cuts across existing occupational boundaries

    Sulphur abundances in metal-poor stars

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    We investigate the debated "sulphur discrepancy" found among metal-poor stars of the Galactic halo with [Fe/H] < -2. This discrepancy stems in part from the use of two different sets of sulphur lines, the very weak triplet at 8694-95 A and the stronger triplet lines at 9212 - 9237 A. For three representative cases of metal-poor dwarf, turnoff and subgiant stars, we argue that the abundances from the 8694-95 lines have been overestimated which has led to a continually rising trend of [S/Fe] as metallicity decreases. Given that the near-IR region is subject to CCD fringing, these weak lines become excessively difficult to measure accurately in the metallicity regime of [Fe/H] < -2. Based on homogeneously determined spectroscopic stellar parameters, we also present updated [S/Fe] ratios from the 9212-9237 lines which suggest a plateau-like behaviour similar to that seen for other alpha elements.Comment: accepted by A&A, 4 pages, 3 tables, 1 figure; v2: Table2 updated with metallicities from other work

    IVUS-based imaging modalities for tissue characterization: similarities and differences

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    Gray-scale intravascular ultrasound (IVUS) is the modality that has been established as the golden standard for in vivo imaging of the vessel wall of the coronary arteries. The use of IVUS in clinical practice is an important diagnostic tool used for quantitative assessment of coronary artery disease. This has made IVUS the de-facto invasive imaging method to evaluate new interventional therapies such as new stent designs and for atherosclerosis progression-regression studies. However, the gray-scale representation of the coronary vessel wall and plaque morphology in combination with the limited resolution of the current IVUS catheters makes it difficult, if not impossible, to identify qualitatively (e.g. visually) the plaque morphology similar as that of histopathology, the golden standard to characterize and quantify coronary plaque tissue components. Meanwhile, this limitation has been partially overcome by new innovative IVUS-based post-processing methods such as: virtual histology IVUS (VH-IVUS, Volcano Therapeutics, Rancho Cordova, CA, USA), iMAP-IVUS (Bostoc Scientific, Santa Clara, CA, USA), Integrated Backscatter IVUS (IB-IVUS) and Automated Differential Echogenicity (ADE)

    Tumour burden in early stage Hodgkin's disease: the single most important prognostic factor for outcome after radiotherapy.

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    One hundred and forty-two patients with Hodgkin's disease PS I or II were treated with total or subtotal nodal irradiation as part of a prospective randomized trial in the Danish National Hodgkin Study during the period 1971-83. They were followed till death or--at the time of this analysis--from 15 to 146 months after initiation of therapy. The initial tumour burden of each patient was assessed, combining tumour size of each involved region and number of regions involved. Tumour burden thus assessed proved to be the single most important prognostic factor with regard to disease free survival. Other known prognostic factors such as number of involved regions, mediastinal size, pathological stage, systemic symptoms, and ESR were related to tumour burden and lost their prognostic significance in a multivariate analysis. The only other factors of independent significance were histologic subtype and, to a lesser extent, sex. Combining tumour burden and histologic subtype made it possible to single out a group of patients with a very poor disease free survival. These patients also had a poorer survival from Hodgkin's disease and thus clearly candidates for additional initial treatment

    Imaging indicator for ESD safety testing.

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    This report describes the development of a new detection method for electrostatic discharge (ESD) testing of explosives, using a single-lens reflex (SLR) digital camera and a 200-mm macro lens. This method has demonstrated several distinct advantages to other current ESD detection methods, including the creation of a permanent record, an enlarged image for real-time viewing as well as extended periods of review, and ability to combine with most other Go/No-Go sensors. This report includes details of the method, including camera settings and position, and results with wellcharacterized explosives PETN and RDX, and two ESD-sensitive aluminum powders

    Australian consumer perspectives, attitudes and behaviours on antibiotic use and antibiotic resistance: A qualitative study with implications for public health policy and practice

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    © 2017 The Author(s). Background: Consumers receive over 27 million antibiotic prescriptions annually in Australian primary healthcare. Hence, consumers are a key group to engage in the fight against antibiotic resistance. There is a paucity of research pertaining to consumers in the Australian healthcare environment. This study aimed to investigate the perspectives, attitudes and behaviours of Australian consumers on antibiotic use and antibiotic resistance, to inform national programs for reducing inappropriate antibiotic consumption. Method: Semi-structured interviews with 32 consumers recruited via convenience and snowball sampling from a university population in South East Queensland. Interview transcripts were deductively and inductively coded. Main themes were identified using iterative thematic analysis. Results: Three themes emerged from the analysis, to elucidate factors affecting antibiotic use: (a) prescription type; (b) consumer attitudes, behaviours, skills and knowledge; and (c) consumer engagement with antibiotic resistance. Consumers held mixed views regarding the use of delayed antibiotic prescriptions, and were often not made aware of the use of repeat antibiotic prescriptions. Consumers with regular general practitioners were more likely to have shared expectations regarding minimising the use of antibiotics. Even so, advice or information mediated by general practitioners was influential with all consumers; and helped to prevent inappropriate antibiotic use behaviours. Consumers were not aware of the free Return of Unwanted Medicines service offered by pharmacies and disposed of leftover antibiotics through household waste. To engage with mitigating antibiotic resistance, consumers required specific information. Previous public health campaigns raising awareness of antibiotics were largely not seen by this sample of consumers. Conclusions: Australian consumers have specific information needs regarding prescribed antibiotics to enable appropriate antibiotic use behaviours. Consumers also have expectations for high quality general practice consults conducted in a manner that increases consumer confidence in the treatment decision, regardless of whether an antibiotic is prescribed. To reduce inappropriate consumption of antibiotics and to more fully engage Australian consumers in mitigating antibiotic resistance, changes in health policy and practice are required

    The 'Forbidden' Abundance of Oxygen in the Sun

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    We reexamine closely the solar photospheric line at 6300 A, which is attributed to a forbidden line of neutral oxygen, and is widely used in analyses of other late-type stars. We use a three-dimensional time-dependent hydrodynamical model solar atmosphere which has been tested successfully against observed granulation patterns and an array of absorption lines. We show that the solar line is a blend with a Ni I line, as previously suggested but oftentimes neglected. Thanks to accurate atomic data on the [O I] and Ni I lines we are able to derive an accurate oxygen abundance for the Sun: log epsilon (O) = 8.69 +/- 0.05 dex, a value at the lower end of the distribution of previously published abundances, but in good agreement with estimates for the local interstellar medium and hot stars in the solar neighborhood. We conclude by discussing the implication of the Ni I blend on oxygen abundances derived from the [O I] 6300 A line in disk and halo stars.Comment: 16 pages, 3 eps figures included; a more compact PostScript version created using emulateapj.sty is available from http://hebe.as.utexas.edu/recent_publi.html; to appear in ApJ
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