1,933 research outputs found

    An investigative study of a spectrum-matching imaging system Final report

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    Evaluation system for classification of remote objects and materials identified by solar and thermal radiation emissio

    Relativistic models of magnetars: the twisted-torus magnetic field configuration

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    We find general relativistic solutions of equilibrium magnetic field configurations in magnetars, extending previous results of Colaiuda et al. (2008). Our method is based on the solution of the relativistic Grad-Shafranov equation, to which Maxwell's equations can be reduced in some limit. We obtain equilibrium solutions with the toroidal magnetic field component confined into a finite region inside the star, and the poloidal component extending to the exterior. These so-called twisted-torus configurations have been found to be the final outcome of dynamical simulations in the framework of Newtonian gravity, and appear to be more stable than other configurations. The solutions include higher order multipoles, which are coupled to the dominant dipolar field. We use arguments of minimal energy to constrain the ratio of the toroidal to the poloidal field.Comment: 13 pages, 12 figures. Minor changes to match the version published on MNRA

    The MiMeS Project: Magnetism in Massive Stars

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    The Magnetism in Massive Stars (MiMeS) Project is a consensus collaboration among the foremost international researchers of the physics of hot, massive stars, with the basic aim of understanding the origin, evolution and impact of magnetic fields in these objects. The cornerstone of the project is the MiMeS Large Program at the Canada-France-Hawaii Telescope, which represents a dedication of 640 hours of telescope time from 2008-2012. The MiMeS Large Program will exploit the unique capabilities of the ESPaDOnS spectropolarimeter to obtain critical missing information about the poorly-studied magnetic properties of these important stars, to confront current models and to guide theory.Comment: 6 pages, 3 figures, proceedings of IAUS 259: Cosmic Magnetic Field

    Development and application of an indicator assessment tool for measuring health services accreditation programs

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    © 2015 Mumford et al. Background: Hospital accreditation programs are internationally widespread and consume increasingly scarce health resources. However, we lack tools to consistently identify suitable indicators to assess and monitor accreditation outcomes. We describe the development and validation of such a tool. Results: Using Australian accreditation standards as our reference point we: reviewed the research evidence for potential indicators; looked for links with existing external indicators; and assessed relevant state and federal policies. We allocated provisional scores, on a five point Likert scale, to the five accountability criteria in the tool: research; accuracy; proximity; no adverse effects; and specificity. An expert panel validated the use of the purpose designed indicator assessment tool. The panel identified hand hygiene compliance rates as a suitable process indicator, and hospital acquired Staphylococcus aureus infection (SAB) rates as an outcome indicator, with the hypothesis that improved hand hygiene compliance rates and lower SAB rates would correlate with accreditation performance. Conclusions: This new tool can be used to identify, analyse, and compare accreditation indicators. Using infection control indicators such as hand hygiene compliance and SAB rates to measure accreditation effectiveness has merit, and their efficacy can be determined by comparing accreditation scores with indicator outcomes. To verify the tool as a robust instrument, testing is needed in other health service domains, both in Australia and internationally. This tool provides health policy makers with an important means for assessing the accreditation programs which form a critical part of the national patient safety and quality framework

    The aetiology of rickets-like lower limb deformities in Malawian children

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    Summary: Debilitating rickets-like lower limb deformities are common in children throughout the world, particularly in Malawi, Africa where the causes are unknown. We have identified that Blount disease and calcium deficiency rickets are the likely causes of these deformities and propose calcium supplementation as a potential treatment of Malawian rickets. Introduction: Surgical correction of rickets-like lower limb deformities is the most common paediatric operation performed at Beit Cure Orthopaedic Hospital, Malawi. The aim of this study was to investigate the aetiology of these deformities. Methods: Children with a tibio-femoral angle of deformity >20° were enrolled (n = 42, 3.0–15.0 years). Anthropometric and early life and well-being data were collected. Early morning serum and urine samples were collected on the morning of the operation for markers of calcium and phosphate homeostasis. Knee radiographs were obtained, and the children were diagnosed with either Blount (BD, n = 22) or evidence of rickets disease (RD, n = 20). As BD is a mechanical rather than metabolic disease, BD were assumed to be biochemically representative of the local population and thus used as a local reference for RD. Results: There were no differences in anthropometry or early life experiences between BD and RD. Parathyroid hormone (PTH), 1,25-dihydroxyvitamin D, total alkaline phosphatase and urinary phosphate were significantly higher and serum phosphate, 25-hydroxyvitamin D (25OHD) and tubular maximal reabsorption of phosphate significantly lower in RD than BD. There was no difference in serum calcium, fibroblast growth factor 23 or markers of iron status between groups. All children had 25OHD > 25 nmol/L. Conclusions: Vitamin D deficiency is not implicated in the aetiology of RD or BD in Malawian children. The cause of RD in Malawi is likely to be dietary calcium deficiency leading to elevated PTH resulting in increased losses of phosphate from the bone and glomerular filtrate. The causes of BD remain unclear; there was no evidence in support of previously suggested risk factors such as being overweight or starting to walk early. Prior to surgical intervention, supplementation with calcium should be considered for children with RD

    Stakeholder perspectives on implementing accreditation programs: A qualitative study of enabling factors

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    Background: Accreditation programs are complex, system-wide quality and safety interventions. Despite their international popularity, evidence of their effectiveness is weak and contradictory. This may be due to variable implementation in different contexts. However, there is limited research that informs implementation strategies. We aimed to advance knowledge in this area by identifying factors that enable effective implementation of accreditation programs across different healthcare settings. Methods. We conducted 39 focus groups and eight interviews between 2011 and 2012, involving 258 diverse healthcare stakeholders from every Australian State and Territory. Interviews were semi-structured and focused on the aims, implementation and consequences of three prominent accreditation programs in the aged, primary and acute care sectors. Data were thematically analysed to distil and categorise facilitators of effective implementation. Results: Four factors were identified as critical enablers of effective implementation: the accreditation program is collaborative, valid and uses relevant standards; accreditation is favourably received by health professionals; healthcare organisations are capable of embracing accreditation; and accreditation is appropriately aligned with other regulatory initiatives and supported by relevant incentives. Conclusions: Strategic implementation of accreditation programs should target the four factors emerging from this study, which may increase the likelihood of accreditation being implemented successfully. © 2013 Hinchcliff et al.; licensee BioMed Central Ltd

    CP and related phenomena in the context of Stellar Evolution

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    We review the interaction in intermediate and high mass stars between their evolution and magnetic and chemical properties. We describe the theory of Ap-star `fossil' fields, before touching on the expected secular diffusive processes which give rise to evolution of the field. We then present recent results from a spectropolarimetric survey of Herbig Ae/Be stars, showing that magnetic fields of the kind seen on the main-sequence already exist during the pre-main sequence phase, in agreement with fossil field theory, and that the origin of the slow rotation of Ap/Bp stars also lies early in the pre-main sequence evolution; we also present results confirming a lack of stars with fields below a few hundred gauss. We then seek which macroscopic motions compete with atomic diffusion in determining the surface abundances of AmFm stars. While turbulent transport and mass loss, in competition with atomic diffusion, are both able to explain observed surface abundances, the interior abundance distribution is different enough to potentially lead to a test using asterosismology. Finally we review progress on the turbulence-driving and mixing processes in stellar radiative zones.Comment: Proceedings of IAU GA in Rio, JD4 on Ap stars; 10 pages, 7 figure
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