12,934 research outputs found

    The provision of distance education within the HE sector - some areas for concern

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    This paper presents a summary of the findings of a recent survey of the way in which UK higher education institutions (HEIs) are offering distance education (DE) courses, the types of courses being offered, and their modes of delivery. From analysis of the findings of this survey, it is apparent that the emphasis of HEIs is very much on the exploitation of available teaching technology in the delivery of DE courses. However, teaching at a distance is quite different from face-toface teaching, and the evidence suggests that many HEIs fail to implement any meaningful academic staff training for the new role of DE tutor. The authors consider the difficulties this presents to academic staff who are required to move from face-to-face teaching to online facilitating. The paper concludes with an examination of the current provision of staff development and training within UK HEIs and suggests the type of academic staff training required if DE courses are to become truly core activities

    Bulk Superconductivity at 14 K in Single Crystals of Fe1+yTexSe1-x

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    Resistivity, magnetic susceptibility and heat capacity measurements are reported for single crystals of Fe1+yTexSe1-x grown via a modified Bridgeman method with 0 < y < 0.15, and x= 1, 0.9, 0.75, 0. 67, 0.55 and 0.5. Although resistivity measurements show traces of superconductivity near 14 K for all x except x=1, only crystals grown with compositions near x=0.5 exhibit bulk superconductivity. The appearance of bulk superconductivity correlates with a reduction in the magnitude of the magnetic susceptibility at room temperature and smaller values of y, the concentration of Fe in the Fe(2) site.Comment: Submitted to Phys. Rev.

    On Exchange of Orbital Angular Momentum Between Twisted Photons and Atomic Electrons

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    We obtain an expression for the matrix element for a twisted (Laguerre-Gaussian profile) photon scattering from a hydrogen atom. We consider photons incoming with an orbital angular momentum (OAM) of \ell \hbar, carried by a factor of eiϕe^{i \ell \phi} not present in a plane-wave or pure Gaussian profile beam. The nature of the transfer of +2+2\ell units of OAM from the photon to the azimuthal atomic quantum number of the atom is investigated. We obtain simple formulae for these OAM flip transitions for elastic forward scattering of twisted photons when the photon wavelength λ\lambda is large compared with the atomic target size aa, and small compared the Rayleigh range zRz_R, which characterizes the collimation length of the twisted photon beam.Comment: 16 page
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