13,734 research outputs found

    Questions of quality in repositories of open educational resources: a literature review

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    Open educational resources (OER) are teaching and learning materials which are freely available and openly licensed. Repositories of OER (ROER) are platforms that host and facilitate access to these resources. ROER should not just be designed to store this content – in keeping with the aims of the OER movement, they should support educators in embracing open educational practices (OEP) such as searching for and retrieving content that they will reuse, adapt or modify as needed, without economic barriers or copyright restrictions. This paper reviews key literature on OER and ROER, in order to understand the roles ROER are said or supposed to fulfil in relation to furthering the aims of the OER movement. Four themes which should shape repository design are identified, and the following 10 quality indicators (QI) for ROER effectiveness are discussed: featured resources; user evaluation tools; peer review; authorship of the resources; keywords of the resources; use of standardised metadata; multilingualism of the repositories; inclusion of social media tools; specification of the creative commons license; availability of the source code or original files. These QI form the basis of a method for the evaluation of ROER initiatives which, in concert with considerations of achievability and long-term sustainability, should assist in enhancement and development. Keywords: open educational resources; open access; open educational practice; repositories; quality assuranc

    Monitoring and controlling bank risk: does risky debt serve any purpose?

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    To examine whether mandating banks to issue subordinated debt would enhance market monitoring and control risk-taking, the authors extract the credit-spread curve for each banking firm in their sample. After controlling for changes in market and liquidity variables, they find that changes in credit spreads do not reflect changes in bank risk variables. The result is robust to firm type, examination rating, size, leverage, and profitability, as well as to different model specifications. They also find that issuing subordinated debt does not alter banks' risk-taking behavior. They conclude that a mandatory subordinated debt requirement for banks is unlikely to provide the intended benefits of enhancing risk-monitoring or controlling risk-taking.Bank capital ; Risk

    Spectrum of turbulent Kelvin-waves cascade in superfluid helium

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    To explain the observed decay of superfluid turbulence at very low temperature, it has been proposed that a cascade of Kelvin waves (analogous to the classical Kolmogorov cascade) transfers kinetic energy to length scales which are small enough that sound can be radiated away. We report results of numerical simulations of the interaction of quantized vortex filaments. We observe the development of the Kelvin-waves cascade, and compute the statistics of the curvature, the amplitude spectrum (which we compare with competing theories) and the fractal dimension.Comment: 32 pages, 22 figure

    Anomalous translational velocity of vortex ring with finite-amplitude Kelvin waves

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    We consider finite-amplitude Kelvin waves on an inviscid vortex assuming that the vortex core has infinitesimal thickness. By numerically solving the governing Biot-Savart equation of motion, we study how the frequency of the Kelvin waves and the velocity of the perturbed ring depend on the Kelvin wave amplitude. In particular, we show that, if the amplitude of the Kelvin waves is sufficiently large, the perturbed vortex ring moves backwards.Comment: 6 pages, 5 figures, v2: minor changes, v3: typos correcte

    Quadrupole Oscillation of a Single-Vortex Condensate: Evidence for Kelvin Modes

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    We study the two transverse quadrupole modes of a cigar-shaped Bose-Einstein condensate with a single centered vortex. We show that the counter-rotating mode is more strongly damped than in the absence of a vortex, whereas the co-rotating mode is not affected appreciably by the vortex. We interpret this result as a decay of the counter-rotating quadrupole mode into two excitations of the vortex line, the so-called Kelvin modes. This is supported by direct observation of the wiggling vortex line.Comment: 4 pages, 3 figure

    Chirality transfer and stereo-selectivity of imprinted cholesteric networks

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    Imprinting of cholesteric textures in a polymer network is a method of preserving a macroscopically chiral phase in a system with no molecular chirality. By modifying the elastics properties of the network, the resulting stored helical twist can be manipulated within a wide range since the imprinting efficiency depends on the balance between the elastics constants and twisting power at network formation. One spectacular property of phase chirality imprinting is the created ability of the network to adsorb preferentially one stereo-component from a racemic mixture. In this paper we explore this property of chirality transfer from a macroscopic to the molecular scale. In particular, we focus on the competition between the phase chirality and the local nematic order. We demonstrate that it is possible to control the subsequent release of chiral solvent component from the imprinting network and the reversibility of the stereo-selective swelling by racemic solvents

    The development and exploratory analysis of the Osteopaths’ Therapeutic Approaches Questionnaire (Osteo-TAQ)

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    Background: Clinical practice encompasses the complex interaction of different skills, knowledge and values in the context of a therapeutic relationship. Research has demonstrated a positive association between well-developed therapeutic relationships, patient satisfaction and clinical outcomes in musculoskeletal conditions. There has been little research into osteopaths’ decision making regarding choice of therapeutic approaches. Aim: The aim of this study was to develop a new questionnaire to assess differences in osteopaths' therapeutic approaches, and to subsequently investigate the internal consistency of the factors identifying different underlying practice concepts and the validity and generalisability of a qualitative grounded theory on osteopaths’ therapeutic approaches and clinical decision-making. Method: A 30-Item Osteopaths’ Therapeutic Approaches Questionnaire (Osteo-TAQ) was developed using modified verbatim phrases from a published qualitative grounded theory. UK osteopaths were invited to complete the Osteo-TAQ questionnaire. An exploratory factor analysis, using both the principal axis factoring method and principal components method, was performed on the responses. Results: 132 responses were received. Osteo-TAQ displayed acceptable level of modelling adequacy (χ2(435) = 1466.1, p < 0.001; KMO = 0.754) and internal consistency (α = 0.778). Exploratory analysis identified eight factors with eigenvalues >1, accounting for 63.5 of the variance. Conclusion: The Osteo-TAQ identified factors that are congruent with a qualitative grounded theory on osteopaths’ therapeutic approaches. The Osteo-TAQ appeared to have good construct validity with four robust components identified and easily characterised. Further testing for construct validity should be carried out amongst a larger population of osteopaths and outside the UK to test and develop the questionnaire further. © 2020 Elsevier Lt

    Topological effects in the thermal properties of knotted polymer rings

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    The topological effects on the thermal properties of several knot configurations are investigated using Monte Carlo simulations. In order to check if the topology of the knots is preserved during the thermal fluctuations we propose a method that allows very fast calculations and can be easily applied to arbitrarily complex knots. As an application, the specific energy and heat capacity of the trefoil, the figure-eight and the 818_1 knots are calculated at different temperatures and for different lengths. Short-range repulsive interactions between the monomers are assumed. The knots configurations are generated on a three-dimensional cubic lattice and sampled by means of the Wang-Landau algorithm and of the pivot method. The obtained results show that the topological effects play a key role for short-length polymers. Three temperature regimes of the growth rate of the internal energy of the system are distinguished.Comment: 7 pages, 12 figures, LaTeX + RevTeX. With respect to the first version, in the second version the text has been improved and all figures are now in black and whit
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