13,918 research outputs found

    Exploring the views of students on the use of Facebook in university teaching and learning

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    Facebook use among students is almost ubiquitous; however, its use for formal academic purposes remains contested. Through an online survey monitoring student use of module Facebook pages and focus groups, this study explores students’ current academic uses of Facebook and their views on using Facebook within university modules. Students reported using Facebook for academic purposes, notably peer–peer communication around group work and assessment – a use not always conceptualised by students as learning. Focus groups revealed that students are not ready or equipped for the collaborative style of learning envisaged by the tutor and see Facebook as their personal domain, within which they will discuss academic topics where they see a strong relevance and purpose, notably in connection with assessment. Students use Facebook for their own mutually defined purposes and a change in student mind- and skill-sets is required to appropriate the collaborative learning benefits of Facebook in formal educational contexts

    A Theorem on the origin of Phase Transitions

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    For physical systems described by smooth, finite-range and confining microscopic interaction potentials V with continuously varying coordinates, we announce and outline the proof of a theorem that establishes that unless the equipotential hypersurfaces of configuration space \Sigma_v ={(q_1,...,q_N)\in R^N | V(q_1,...,q_N) = v}, v \in R, change topology at some v_c in a given interval [v_0, v_1] of values v of V, the Helmoltz free energy must be at least twice differentiable in the corresponding interval of inverse temperature (\beta(v_0), \beta(v_1)) also in the N -> \inftylimit.Thustheoccurrenceofaphasetransitionatsomeβc=β(vc)isnecessarilytheconsequenceofthelossofdiffeomorphicityamongtheΣvv<vc limit. Thus the occurrence of a phase transition at some \beta_c =\beta(v_c) is necessarily the consequence of the loss of diffeomorphicity among the {\Sigma_v}_{v < v_c} and the {\Sigma_v}_{v > v_c}, which is the consequence of the existence of critical points of V on \Sigma_{v=v_c}, that is points where \nabla V=0.Comment: 10 pages, Statistical Mechanics, Phase Transitions, General Theory. Phys. Rev. Lett., in pres

    Panel Discussion On The Clinical Management Of Blood Dyscrasias In The Older Age Group†

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111245/1/jgs00338.pd

    Accuracy of one-dimensional collision integral in the rigid spheres approximation

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    The accuracy of calculation of spectral line shapes in one-dimensional approximation is studied analytically in several limiting cases for arbitrary collision kernel and numerically in the rigid spheres model. It is shown that the deviation of the line profile is maximal in the center of the line in case of large perturber mass and intermediate values of collision frequency. For moderate masses of buffer molecules the error of one-dimensional approximation is found not to exceed 5%.Comment: LaTeX, 24 pages, 8 figure

    Measurement of Partial-Wave Contributions in pp --> pp pi^0

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    We report a measurement of the spin-dependent total cross section ratios delta_sigma_T/sigma_tot and delta_sigma_L/sigma_tot of the pp --> pp pi^0 reaction between 325 MeV and 400 MeV. The experiment was carried out with a polarized internal target in a storage ring. Non-vertical beam polarization was obtained by the use of solenoidal spin rotators. Near threshold, the knowledge of both spin-dependent total cross sections is sufficient to deduce the strength of certain participating partial waves, free of any model.Comment: 6 pages, 4 figure

    Diffractive triangulation of radiative point sources

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    We describe a general method to determine the location of a point source of waves relative to a twodimensional single-crystalline active pixel detector. Based on the inherent structural sensitivity of crystalline sensor materials, characteristic detector diffraction patterns can be used to triangulate the location of a wave emitter. The principle described here can be applied to various types of waves, provided that the detector elements are suitably structured. As a prototypical practical application of the general detection principle, a digital hybrid pixel detector is used to localize a source of electrons for Kikuchi diffraction pattern measurements in the scanning electron microscope. This approach provides a promising alternative method to calibrate Kikuchi patterns for accurate measurements of microstructural crystal orientations, strains, and phase distributions

    Spin correlations in pppnπ+\vec{p}\vec{p}\to pn\pi^{+} pion production near threshold

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    A first measurement of longitudinal as well as transverse spin correlation coefficients for the reaction pppnπ+\vec{p}\vec{p}\to pn\pi^+ was made using a polarized proton target and a polarized proton beam. We report kinematically complete measurements for this reaction at 325, 350, 375 and 400 MeV beam energy. The spin correlation coefficients Axx+Ayy,AxxAyy,Azz,Axz,A_{xx}+A_{yy}, A_{xx}-A_{yy}, A_{zz}, A_{xz}, and the analyzing power Ay,A_{y}, as well as angular distributions for σ(θπ)\sigma(\theta_{\pi}) and the polarization observables Aij(θπ)A_{ij}(\theta_{\pi}) were extracted. Partial wave cross sections for dominant transition channels were obtained from a partial wave analysis that included the transitions with final state angular momenta of l1l\leq 1. The measurements of the pppnπ+{\vec{p}\vec{p}\to pn\pi^{+}} polarization observables are compared with the predictions from the J\"ulich meson exchange model. The agreement is very good at 325 MeV, but it deteriorates increasingly for the higher energies. At all energies agreement with the model is better than for the reaction ppppπ0{\vec{p}\vec{p}\to pp\pi^{0}}.Comment: Preprint, 21 pp, submitted to Phys. Rev. C. Keywords: Mesons, Polarization, Spin Correlations, Few body system

    Dependence of pp->pp pi0 near Threshold on the Spin of the Colliding Nucleons

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    A polarized internal atomic hydrogen target and a stored, polarized beam are used to measure the spin-dependent total cross section Delta_sigma_T/sigma_tot, as well as the polar integrals of the spin correlation coefficient combination A_xx-A_yy, and the analyzing power A_y for pp-> pp pi0 at four bombarding energies between 325 and 400 MeV. This experiment is made possible by the use of a cooled beam in a storage ring. The polarization observables are used to study the contribution from individual partial waves.Comment: 6 pages, 1 table, 4 figures, corrected equations 2 and
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