575 research outputs found

    Tuberculous pancreatitis complicated by ruptured splenic artery pseudoaneurysm

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    Tuberculous pancreatitis complicated by ruptured splenic artery pseudoaneurysm. M. Irfan, F. Thiavalappil, J. Nagaraj, T.H. Brown, D. Roberts, L. Mcknight, N.K. Harrison. Tuberculosis involving the pancreas is rare. We report a patient with pancreatic tuberculosis complicated by haemorrhage from a splenic artery pseudoaneurysm. As far as we are aware, the development of a splenic artery pseudoaneurysm in association with a large caseating mass of tuberculous pancreatic lymph nodes has not been reported previously. We review the literature and discuss the varied presentations of tuberculosis involving the pancreas or the pancreatic bed and its draining lymph nodes

    Pair creation: back-reactions and damping

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    We solve the quantum Vlasov equation for fermions and bosons, incorporating spontaneous pair creation in the presence of back-reactions and collisions. Pair creation is initiated by an external impulse field and the source term is non-Markovian. A simultaneous solution of Maxwell's equation in the presence of feedback yields an internal current and electric field that exhibit plasma oscillations with a period tau_pl. Allowing for collisions, these oscillations are damped on a time-scale, tau_r, determined by the collision frequency. Plasma oscillations cannot affect the early stages of the formation of a quark-gluon plasma unless tau_r >> tau_pl and tau_pl approx. 1/Lambda_QCD approx 1 fm/c.Comment: 16 pages, 6 figure, REVTEX, epsfig.st

    Guidelines for the Selection of Physical Literacy Measures in Physical Education in Australia

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    Assessment of physical literacy poses a dilemma of what instrument to use. There is currently no guide regarding the suitability of common assessment approaches. The purpose of this brief communication is to provide a user's guide for selecting physical literacy assessment instruments appropriate for use in school physical education and sport settings. While recommendations regarding specific instruments are not provided, the guide offers information about key attributes and considerations for the use. A decision flow chart has been developed to assist teachers and affiliated school practitioners to select appropriate methods of assessing physical literacy. School PE and sport scenarios are presented to illustrate this process. It is important that practitioners are empowered to select the most appropriate instrument/s to suit their needs

    The ethos of physical activity delivery in mental health: a narrative study of service user experiences.

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    Our research into the physical activity experiences of people with severe mental illness has led us to take seriously the social and cultural environment in which physical activity is delivered. In this study, through narrative methodology, we examine service user accounts of physical activity to illuminate the characteristics of physical activity groups that are experienced as positive, helpful, or beneficial. We present several qualities and show how effective leadership and coaching is central to these qualities being present. We conclude that it is not so much what activity is delivered, but how it is delivered that is critical for sustained participation and positive outcomes

    Defining Physical Literacy for Application in Australia: A Modified Delphi Method

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    Purpose. The development of a physical literacy definition and standards framework suitable for implementation in Australia. Method. Modified Delphi methodology. Results . Consensus was established on four defining statements: Core – Physical literacy is lifelong holistic learning acquired and applied in movement and physical activity contexts; Composition – Physical literacy reflects ongoing changes integrating physical, psychological, cognitive and social capabilities; Importance – Physical literacy is vital in helping us lead healthy and fulfilling lives through movement and physical activity; Aspiration – A physically literate person is able to draw on their integrated physical, psychological, cognitive, and social capacities to support health promoting and fulfilling movement and physical activity, relative to their situation and context, throughout the lifespan. The standards framework addressed four learning domains (physical, psychological, cognitive, and social), spanning five learning configurations/levels. Conclusion. The development of a bespoke program for a new context has important implications for both existing and future program

    Community indicators: a framework for observing and supporting community activity on Cloudworks

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    Cloudworks (Cloudworks.ac.uk) is a social networking site designed for sharing, finding and discussing learning and teaching ideas and experiences. Design and development of the site has been based on an iterative analysis, development and implementation approach, underpinned by ongoing research and evaluation. To this end, we have been seeking to establish strategies to enable us to systematically position transactions and emerging patterns of activity on the site so that we can more reliably use the empirical evidence we have gathered (Galley, 2009a, Galley 2009b, Alevizou et al., 2010a, Conole et al, 2010). In this paper we will introduce a framework we have developed for observing and supporting community development on the site. In building our framework we have used empirical evidence gathered from the site, then related it to the literature from a range of disciplines concerned with professional and learning communities. We link research relating to distance learning communities with studies into Computer Mediated Communication (CMC), self-organising communities on the web, and wider research about the nature of learning organisations and continuous professional development. We argue that this framework can be used to capture the development of productive communities in the space (i.e. how far cohesive, productive groups can be said to be emerging or not) and also help focus futur

    Analytic properties of the Landau gauge gluon and quark propagators

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    We explore the analytic structure of the gluon and quark propagators of Landau gauge QCD from numerical solutions of the coupled system of renormalized Dyson--Schwinger equations and from fits to lattice data. We find sizable negative norm contributions in the transverse gluon propagator indicating the absence of the transverse gluon from the physical spectrum. A simple analytic structure for the gluon propagator is proposed. For the quark propagator we find evidence for a mass-like singularity on the real timelike momentum axis, with a mass of 350 to 500 MeV. Within the employed Green's functions approach we identify a crucial term in the quark-gluon vertex that leads to a positive definite Schwinger function for the quark propagator.Comment: 42 pages, 16 figures, revtex; version to be published in Phys Rev

    Current status of turbulent dynamo theory: From large-scale to small-scale dynamos

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    Several recent advances in turbulent dynamo theory are reviewed. High resolution simulations of small-scale and large-scale dynamo action in periodic domains are compared with each other and contrasted with similar results at low magnetic Prandtl numbers. It is argued that all the different cases show similarities at intermediate length scales. On the other hand, in the presence of helicity of the turbulence, power develops on large scales, which is not present in non-helical small-scale turbulent dynamos. At small length scales, differences occur in connection with the dissipation cutoff scales associated with the respective value of the magnetic Prandtl number. These differences are found to be independent of whether or not there is large-scale dynamo action. However, large-scale dynamos in homogeneous systems are shown to suffer from resistive slow-down even at intermediate length scales. The results from simulations are connected to mean field theory and its applications. Recent work on helicity fluxes to alleviate large-scale dynamo quenching, shear dynamos, nonlocal effects and magnetic structures from strong density stratification are highlighted. Several insights which arise from analytic considerations of small-scale dynamos are discussed.Comment: 36 pages, 11 figures, Spa. Sci. Rev., submitted to the special issue "Magnetism in the Universe" (ed. A. Balogh

    Yukawa structure, flavour and CP violation in Supergravity

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    The hierarchical structure of fermion masses and mixings strongly suggests an underlying family symmetry. In supergravity any familon field spontaneously breaking this symmetry necessarily acquires an F-term which contributes to the soft trilinear couplings. We show, as a result, mu -> e gamma decay can receive large contributions from this source at the level of current experimental bounds and thus this channel may provide the first indication of supersymmetry and a clue to the structure of the soft breaking sector. Using the mercury EDM bounds we find strong bounds on the right handed down quark mixing angles that are inconsistent with models relating them to neutrino mixing angles and favour a near-symmetric form for the magnitude of the down quark mass matrix.Comment: Final version to appear in PRD. Improved discusion of several points, updated references, typos correcte
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