829 research outputs found

    Status of undergraduate community-based and public-health physiotherapy education in South Africa

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    Curricula of health education institutions therefore need to be periodically revised to be aligned with its context. This study explored the status physiotherapy curricula in South Africa (SA) as point of departure for benchmarking by individual institutions. A document analysis was done of the university physiotherapy departments (N=8) in South Africa. Institutional ethical clearance and permission from the heads of departments were obtained. Content analysis was used to analyse the South African Qualifications Authority exit-level outcomes and the university study guides for community placements. Most universities employed a form of service-learning, with interventions in a range of settings. Five themes emerged: practice of evidence-based physiotherapy, rendering physiotherapy services, acting professionally, communication, and collaboration. The country’s priority conditions were addressed. Teaching-earning strategies included group activities (class or education sessions), community projects, home visits and portfolios of evidence. Personal and small-group reflections were prominent. The undergraduate community physiotherapy curricula in South Africa address the health profile of the population and priorities in the health system to different degrees. The variation between universities should be interpreted with caution as the study guides only gave a limited snapshot into each institution’s curriculum. However, findings suggest that each physiotherapy university department may have gaps in preparing physiotherapy undergraduate students for the needs of the South African population and expectations of the Government. Possible ways to share teaching-learning resources are recommended.Department of HE and Training approved lis

    Space Symmetries and Quantum Behavior of Finite Energy Configurations in SU(2)-Gauge Theory

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    The quantum properties of localized finite energy solutions to classical Euler-Lagrange equations are investigated using the method of collective coordinates. The perturbation theory in terms of inverse powers of the coupling constant gg is constructed, taking into account the conservation laws of momentum and angular momentum (invariance of the action with respect to the group of motion M(3) of 3-dimensional Euclidean space) rigorously in every order of perturbation theory.Comment: LaTex, 17 pages typos correcte

    Magnetic Flux Expulsion in the Powerful Superbubble Explosions and the Alpha-Omega Dynamo

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    The possibility of the magnetic flux expulsion from the Galaxy in the superbubble (SB) explosions, important for the Alpha-Omega dynamo, is considered. Special emphasis is put on the investigation of the downsliding of the matter from the top of the shell formed by the SB explosion which is able to influence the kinematics of the shell. It is shown that either Galactic gravity or the development of the Rayleigh-Taylor instabilities in the shell limit the SB expansion, thus, making impossible magnetic flux expulsion. The effect of the cosmic rays in the shell on the sliding is considered and it is shown that it is negligible compared to Galactic gravity. Thus, the question of possible mechanism of flux expulsion in the Alpha-Omega dynamo remains open.Comment: MNRAS, in press, 11 pages, 9 figure

    Logarithmic perturbation theory for quasinormal modes

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    Logarithmic perturbation theory (LPT) is developed and applied to quasinormal modes (QNMs) in open systems. QNMs often do not form a complete set, so LPT is especially convenient because summation over a complete set of unperturbed states is not required. Attention is paid to potentials with exponential tails, and the example of a Poschl-Teller potential is briefly discussed. A numerical method is developed that handles the exponentially large wavefunctions which appear in dealing with QNMs.Comment: 24 pages, 4 Postscript figures, uses ioplppt.sty and epsfig.st

    Steps in the bacterial flagellar motor

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    The bacterial flagellar motor is a highly efficient rotary machine used by many bacteria to propel themselves. It has recently been shown that at low speeds its rotation proceeds in steps [Sowa et al. (2005) Nature 437, 916--919]. Here we propose a simple physical model that accounts for this stepping behavior as a random walk in a tilted corrugated potential that combines torque and contact forces. We argue that the absolute angular position of the rotor is crucial for understanding step properties, and show this hypothesis to be consistent with the available data, in particular the observation that backward steps are smaller on average than forward steps. Our model also predicts a sublinear torque-speed relationship at low torque, and a peak in rotor diffusion as a function of torque

    Small denominators, frequency operators, and Lie transforms for nearly integrable quantum spin systems

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    Based on the previously proposed notions of action operators and of quantum integrability, frequency operators are introduced in a fully quantum-mechanical setting. They are conceptually useful because another formulation can be given to unitary perturbation theory. When worked out for quantum spin systems, this variant is found to be formally equivalent to canonical perturbation theory applied to nearly integrable systems consisting of classical spins. In particular, it becomes possible to locate the quantum-mechanical operator-valued equivalent of the frequency denominators that may cause divergence of the classical perturbation series. The results that are established here link the concept of quantum-mechanical integrability to a technical question, namely, the behavior of specific perturbation series

    Conserving Gapless Mean-Field Theory for Weakly Interacting Bose Gases

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    This paper presents a conserving gapless mean-field theory for weakly interacting Bose gases. We first construct a mean-field Luttinger-Ward thermodynamic functional in terms of the condensate wave function Ψ\Psi and the Nambu Green's function G^\hat{G} for the quasiparticle field. Imposing its stationarity respect to Ψ\Psi and G^\hat{G} yields a set of equations to determine the equilibrium for general non-uniform systems. They have a plausible property of satisfying the Hugenholtz-Pines theorem to provide a gapless excitation spectrum. Also, the corresponding dynamical equations of motion obey various conservation laws. Thus, the present mean-field theory shares two important properties with the exact theory: ``conserving'' and ``gapless.'' The theory is then applied to a homogeneous weakly interacting Bose gas with s-wave scattering length aa and particle mass mm to clarify its basic thermodynamic properties under two complementary conditions of constant density nn and constant pressure pp. The superfluid transition is predicted to be first-order because of the non-analytic nature of the order-parameter expansion near TcT_{c} inherent in Bose systems, i.e., the Landau-Ginzburg expansion is not possible here. The transition temperature TcT_{c} shows quite a different interaction dependence between the nn-fixed and pp-fixed cases. In the former case TcT_{c} increases from the ideal gas value T0T_{0} as Tc/T0=1+2.33an1/3T_{c}/T_{0}= 1+ 2.33 an^{1/3}, whereas it decreases in the latter as Tc/T0=13.84a(mp/2π2)1/5T_{c}/T_{0}= 1- 3.84a(mp/2\pi\hbar^{2})^{1/5}. Temperature dependences of basic thermodynamic quantities are clarified explicitly.Comment: 19 pages, 8 figure

    Use of Modal Acoustic Emission to Monitor Damage Progression in Carbon Fiber/Epoxy Tows and Implications for Composite Structures

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    This slide presentation reviews the use of Modal Acoustic Emission to monitor damage progression to carbon fiber/epoxy tows. There is a risk for catastrophic failure of composite overwrapped pressure vessels (COPVs) due to burst-before-leak (BBL) stress rupture (SR) failure of carbon-epoxy (C/Ep) COPVs. A lack of quantitative nondestructive evaluation (NDE) is causing problems in current and future spacecraft designs. It is therefore important to develop and demonstrate critical NDE that can be implemented during stages of the design process since the observed rupture can occur with little of no advanced warning. Therefore a program was required to develop quantitative acoustic emission (AE) procedures specific to C/Ep overwraps, but which also have utility for monitoring damage accumulation in composite structure in general, and to lay the groundwork for establishing critical thresholds for accumulated damage in composite structures, such as COPVs, so that precautionary or preemptive engineering steps can be implemented to minimize of obviate the risk of catastrophic failure. A computed Felicity Ratio (FR) coupled with fast Fourier Transform (FFT) frequency analysis shows promise as an analytical pass/fail criterion. The FR analysis and waveform and FFT analysis are reviewe

    Stochastic Cellular Automata Model for Stock Market Dynamics

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    In the present work we introduce a stochastic cellular automata model in order to simulate the dynamics of the stock market. A direct percolation method is used to create a hierarchy of clusters of active traders on a two dimensional grid. Active traders are characterised by the decision to buy, (+1), or sell, (-1), a stock at a certain discrete time step. The remaining cells are inactive,(0). The trading dynamics is then determined by the stochastic interaction between traders belonging to the same cluster. Most of the stylized aspects of the financial market time series are reproduced by the model.Comment: 17 pages and 7 figure

    Perturbative Approach to the Quasinormal Modes of Dirty Black Holes

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    Using a recently developed perturbation theory for uasinormal modes (QNM's), we evaluate the shifts in the real and imaginary parts of the QNM frequencies due to a quasi-static perturbation of the black hole spacetime. We show the perturbed QNM spectrum of a black hole can have interesting features using a simple model based on the scalar wave equation.Comment: Published in PR
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