4,749 research outputs found

    Smooth Random Surfaces from Tight Immersions?

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    We investigate actions for dynamically triangulated random surfaces that consist of a gaussian or area term plus the {\it modulus} of the gaussian curvature and compare their behavior with both gaussian plus extrinsic curvature and ``Steiner'' actions.Comment: 7 page

    An Effective Model for Crumpling in Two Dimensions?

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    We investigate the crumpling transition for a dynamically triangulated random surface embedded in two dimensions using an effective model in which the disordering effect of the XX variables on the correlations of the normals is replaced by a long-range ``antiferromagnetic'' term. We compare the results from a Monte Carlo simulation with those obtained for the standard action which retains the XX's and discuss the nature of the phase transition.Comment: 5 page

    Ising Model Coupled to Three-Dimensional Quantum Gravity

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    We have performed Monte Carlo simulations of the Ising model coupled to three-dimensional quantum gravity based on a summation over dynamical triangulations. These were done both in the microcanonical ensemble, with the number of points in the triangulation and the number of Ising spins fixed, and in the grand canoncal ensemble. We have investigated the two possible cases of the spins living on the vertices of the triangulation (``diect'' case) and the spins living in the middle of the tetrahedra (``dual'' case). We observed phase transitions which are probably second order, and found that the dual implementation more effectively couples the spins to the quantum gravity.Comment: 11 page

    Changing assessment practice in engineering: how can understanding lecturer perspectives help?

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    Assessment in engineering disciplines is typically oriented to demonstrating competence in specific tasks. Even where assessments are intended to have a formative component, little priority may be given to feedback. Engineering departments are often criticized, by their students and by external quality reviewers, for paying insufficient attention to formative assessment. The e3an project set out to build a question bank of peer-reviewed questions for use within electrical and electronic engineering. As a part of this process, a number of engineers from disparate institutions were required to work together in teams, designing a range of assessments for their subject specialisms. The project team observed that lecturers were especially keen to develop formative assessment but that their understanding of what might be required varied considerably. This paper describes the various ways in which the processes of the project have engaged lecturers in actively identifying and developing their conceptions of teaching, learning and assessment in their subject. It reports on an interview study that was conducted with a selection of participants. It is concluded that lecturers' reflections on and understanding of assessment are closely related to the nature of the subject domain and that it is essential when attempting to improve assessment practice to start from the perspective of lecturers in the discipline

    The Inclusive Semileptonic Decay Lepton Spectrum from B→Xeν‾B \to X e \overline{\nu}

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    In this talk, we review the QCD calculation of the lepton spectrum from inclusive semileptonic BB decay. We compare this prediction to that of the ACCMM model. This latter work was done in collaboration with Csaba Csaki.Comment: MIT-CTP-2333, uses LATEX. Invited Talk, Presented at WHEPP-3 Workshop in Madras,India, January, 199
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