26,484 research outputs found

    The imperial war museum’s social interpretation project

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    This report represents the output from research undertaken by University of Salford and MTM London as part of the joint Digital R&D Fund for Arts and Culture, operated by Nesta, Arts Council England and the AHRC. University of Salford and MTM London received funding from the programme to act as researchers on the Social Interpretation (SI) project, which was led by the Imperial War Museum (IWM) and their technical partners, The Centre for Digital Humanities, University College London, Knowledge Integration, and Gooii. The project was carried out between October 2011 and October 2012

    A Variational Approach for Minimizing Lennard-Jones Energies

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    A variational method for computing conformational properties of molecules with Lennard-Jones potentials for the monomer-monomer interactions is presented. The approach is tailored to deal with angular degrees of freedom, {\it rotors}, and consists in the iterative solution of a set of deterministic equations with annealing in temperature. The singular short-distance behaviour of the Lennard-Jones potential is adiabatically switched on in order to obtain stable convergence. As testbeds for the approach two distinct ensembles of molecules are used, characterized by a roughly dense-packed ore a more elongated ground state. For the latter, problems are generated from natural frequencies of occurrence of amino acids and phenomenologically determined potential parameters; they seem to represent less disorder than was previously assumed in synthetic protein studies. For the dense-packed problems in particular, the variational algorithm clearly outperforms a gradient descent method in terms of minimal energies. Although it cannot compete with a careful simulating annealing algorithm, the variational approach requires only a tiny fraction of the computer time. Issues and results when applying the method to polyelectrolytes at a finite temperature are also briefly discussed.Comment: 14 pages, uuencoded compressed postscript fil

    First Steps Toward Change in Teacher Preparation for Elementary Science

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    Unless introductory undergraduate science classes for prospective elementary teachers actively incorporate the philosophy of inquiry-based learning called for in K-l2 science education refom little will change in elementary science education. Thus, at James Madison University, we have developed a new integrated science core curriculum called Understanding our World [1]. This course sequence was not only designed to fulfill general education science requirements. but also to focus on content areas our students will need to know as teachers. The objectives of these courses are based on the National Science Education Standards and Virginia’s Science Standards of Learning, including earth and space science, chemistry, physics, life sciences, and environmental science [2,3]. As an integrated package, this course sequence addresses basic science content, calculation skills, the philosophy and history of science, the process of how science is done, the role of science in society, and applications of computers and technology in science. Keeping in mind that students tend to teach in the same way they were taught, Understanding our World core classes embrace the concepts associated with reform in elementary math and science

    Evaluation of bistable systems versus matched filters in detecting bipolar pulse signals

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    This paper presents a thorough evaluation of a bistable system versus a matched filter in detecting bipolar pulse signals. The detectability of the bistable system can be optimized by adding noise, i.e. the stochastic resonance (SR) phenomenon. This SR effect is also demonstrated by approximate statistical detection theory of the bistable system and corresponding numerical simulations. Furthermore, the performance comparison results between the bistable system and the matched filter show that (a) the bistable system is more robust than the matched filter in detecting signals with disturbed pulse rates, and (b) the bistable system approaches the performance of the matched filter in detecting unknown arrival times of received signals, with an especially better computational efficiency. These significant results verify the potential applicability of the bistable system in signal detection field.Comment: 15 pages, 9 figures, MikTex v2.

    Strong Optomechanical Squeezing of Light

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    We create squeezed light by exploiting the quantum nature of the mechanical interaction between laser light and a membrane mechanical resonator embedded in an optical cavity. The radiation pressure shot noise (fluctuating optical force from quantum laser amplitude noise) induces resonator motion well above that of thermally driven motion. This motion imprints a phase shift on the laser light, hence correlating the amplitude and phase noise, a consequence of which is optical squeezing. We experimentally demonstrate strong and continuous optomechanical squeezing of 1.7 +/- 0.2 dB below the shot noise level. The peak level of squeezing measured near the mechanical resonance is well described by a model whose parameters are independently calibrated and that includes thermal motion of the membrane with no other classical noise sources.Comment: 12 pages, 8 figure
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