7,563 research outputs found

    What is the potential of distance education for learning and practice development in critical care nursing in the South Island of New Zealand? : a thesis presented in partial fulfilment of the requirements for the degree of Master of Education in Adult Education at Massey University

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    This thesis explores the potential of distance approaches to teaching and learning in post registration nursing education within the context of critical care nursing practice. The thesis specifically considers the appropriateness of distance education within the population of critical care nurses in the South Island of New Zealand. The geographical distribution of critical care services and subsequent population distribution of practising critical care nurses within the South Island has resulted in a demand for post registration education from relatively small yet distinct groups of nurses spanning a substantial land area (150,461 Km2). National shortages of experienced and qualified critical care nurses, and consensus regarding the necessity for post registration education for specialist practice have been recognised throughout the Western World (Ball 1992, Charlton, Machin and Clough 2000, Cutler 2000, Johnston 2002). Yet nurses in the South Island of New Zealand have limited provision or access to critical care education programmes (Hardcastle 2003). The thesis therefore presents a pertinent and timely exploration into the potential of distance approaches to educational provision for an area of specialist practice that is currently unable to consistently meet health care demands. The thesis uses descriptive and interpretive research (previously conducted by the author), and relevant literature in order to provide a comprehensive exploration of the study context and consider the research question. The thesis aims to enhance understanding of the specific population in terms of educational provision and demand, and the meaning of 'effective' education for critical care nursing practice. Subsequent examination of the potential of distance education within this context will more clearly indicate whether distance approaches could be compatible with concepts of effective education. The outcome of which will be useful in order to determine educational strategies that may positively influence the future of education for critical care nursing practice within the South Island of New Zealand

    What determines the properties of the X-ray jets in FR-I radio galaxies?

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    We present the first large sample investigation of the properties of jets in Fanaroff and Riley type I radio galaxies (FR-I) based on data from the Chandra archive. We explore relations between the properties of the jets and the properties of host galaxies in which they reside. We find previously unknown correlations to exist, relating photon index, volume emissivity, jet volume and luminosity, and find that the previously long held assumption of a relationship between luminosities at radio and X-ray wavelengths is linear in nature when bona fide FR-I radio galaxies are considered. In addition, we attempt to constrain properties which may play a key role in determination of the diffuse emission process. We test a simple model in which large-scale magnetic field variations are primarily responsible for determining jet properties; however, we find that this model is inconsistent with our best estimates of the relative magnetic field strength in our sample. Models of particle acceleration should attempt to account for our results if they are to describe FR-I jets accurately.Comment: 14 Pages, 2 Figures, 9 Tables, Final Version, Published in MNRA

    The properties of powerful radio sources at 90 GHz

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    ‘The definitive version is available at www.blackwell-synergy.com.’ Copyright Blackwell Publishing DOI: 10.1111/j.1365-2966.2008.13370.xPeer reviewe

    The particle content of low-power radio galaxies in groups and clusters

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    The synchrotron-radiating particles and magnetic fields in low-power radio galaxies (including most nearby cluster-centre sources), if at equipartition, can provide only a small fraction of the total internal energy density of the radio lobes or plumes, which is now well constrained via X-ray observations of their external environments. We consider the constraints on models for the dominant energy contribution in low-power radio-galaxy lobes obtained from a detailed comparison of how the internal equipartition pressure and external pressure measured from X-ray observations evolve with distance for two radio galaxies, 3C 31 and Hydra A. We rule out relativistic lepton dominance of the radio lobes, and conclude that models in which magnetic field or relativistic protons/ions carried up the jet dominate lobe energetics are unlikely. Finally, we argue that entrainment of material from the jet surroundings can provide the necessary pressure, and construct a simple self-consistent model of the evolution of the entrainment rate required for pressure balance along the 100-kpc-scale plumes of 3C 31. Such a model requires that the entrained material is heated to temperatures substantially above that of the surrounding intragroup medium, and that the temperature of the thermal component of the jet increases with distance, though remaining sub-relativistic.Peer reviewe

    A VLA Study of 15 3CR Radio Galaxies

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    We present VLA radio maps in total intensity and polarization at 1.4, 4.9 and 8.4 GHz of fifteen 3CR radio galaxies for which good maps showing the large-scale radio structure have not previously been available. Previously unknown cores are detected in several sources and a bright one-sided jet in 3C 287.1 is mapped for the first time; several other jet-like features are also imaged. Total and core fluxes are tabulated and radio core positions are listed and compared to optical positions. The galaxy at the optical position listed for 3C 169.1 is found to lie farther from the radio core position than another dimmer, bluer galaxy. We discuss individual sources in some detail.Comment: 35 pages, 22 figures but 35 separate Postscript figure files, AASTeX, Accepted for publication in the Astrophysical Journal Supplemen

    Bond Length - Bond Valence Relationships for Carbon - Carbon and Carbon - Oxygen Bonds

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    In the present study, relationships are developed for determining bond orders (also referred to as bond valences or bond numbers) from published bond lengths for carbon-carbon (C-C) and carbon-oxygen (C-O) bonds. The relationships are based on Pauling’s empirical formula s = exp((Ro-R)/b)), where s is the bond order, R is the corresponding bond length, Ro is the unit valence bond length, and b is a fitting parameter. We use a recently derived relationship for the b parameter in terms of the bonding atoms’ published atomic orbital exponents. The resulting equations were checked against published x-ray diffraction (XRD) data for 176 carbon systems with 540 published C-C bond lengths, and 50 oxygen systems having 72 published C-O bond lengths. The C-C and C-O bond length-valence relationships are shown to have sufficient applicability and accuracy for use in any bonding environment, regardless of physical state or oxidation number

    Theoretical Justification for Bond Valence -- Bond Length Empirical Correlations

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    Bond valence – bond length empirical correlations are of great interest in chemistry, biology, geology and materials science because they offer a quick and convenient way of checking and evaluating molecular structures. Linus Pauling’s relationship is the most commonly used, but is a two-parameter fit where R0 and b must be optimized. In this study, a simplified quantum-mechanical approach was used to derive Pauling’s empirical bond valence – bond length relationship. A covalency factor was also introduced to account for the difference in “softness” between cation and anion (resulting in increased orbital overlap). An expression for the b parameter was determined that yields values that are in agreement with experimental data. The derived relationship for the b parameter allows an independent determination of b using orbital exponents and electronegativity values for the cation and anion

    The Gaseous Environments of Radio Galaxies

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    X-ray emission traces the gaseous environments of radio sources. The medium must be present for jet confinement, but what are its influence on jet fuelling, dynamics, propagation, and disruption? The observational situation is both complicated and enriched by radio sources being multi-component X-ray emitters, with several possible regions of non-thermal emission. Recent work, primarily based on sensitive ROSAT pointings, is used to contrast the X-ray emission and environments of radio sources with (a) low power, (b) high power at high redshift, (c) high power at lower redshift, and (d) GHz peaked spectrum emission. The trends in external gas density and pressure near extended radio structures are reviewed. Imminently-available X-ray measurements with vastly improved resolution and sensitivity have great potential for resolving many open issues.Comment: 20 pages, including 11 figures, using elsart.sty to appear in `Life Cycles of Radio Galaxies' ed. J Biretta et al., New Astronomy Reviews (Elsevier Science

    Interpreting radiative efficiency in radio-loud AGNs

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    Author submitted version of unrefereed Nature Astronomy comment. Version in journal format available at https://rdcu.be/KH6WRadiative efficiency in radio-loud active galactic nuclei is governed by the accretion rate onto the central black hole rather than directly by the type of accreted matter; while it correlates with real differences in host galaxies and environments, it does not provide unambiguous information about particular objects.Non peer reviewedFinal Accepted Versio