51,780 research outputs found

    Integration of Technology in Math and Science Education – A Model for Teaching Elementary and Middle School Pre-Service Teachers

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    This paper describes the development and implementation of a course, Integration of Technology in Math and Science Education, to introduce elementary and middle school pre-service teachers to real technology skills that they can use in their future classrooms. Activities allowed the students to learn technology skills while using the Internet to enrich their content skills and share information with their fellow students. The course was designed to allow students to master a variety of technology skills, and see how these skills can be used appropriately in their future classrooms, while also increasing their comfort level to use the technology and reduce their resistance and anxiety to use it later in their real-time classrooms. During the class hands-on activities, the students became fluent at using the Internet for enrichment and communication, and at developing strategies for using their new skills to present SOL-relevant lesson plans. Students enter this course with very little in the way of educational technology skills, but leave with a teaching toolbox filled with new skills

    Neutrino reactions on 138^{138}La and 180^{180}Ta via charged and neutral currents by the Quasi-particle Random Phase Approximation (QRPA)

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    Cosmological origins of the two heaviest odd-odd nuclei, 138^{138}La and 180^{180}Ta, are believed to be closely related to the neutrino-process. We investigate in detail neutrino-induced reactions on the nuclei. Charged current (CC) reactions, 138^{138}Ba(νe,e)138 (\nu_e, e^{-}) ^{138}La and 180^{180}Hf(νe,e)180 (\nu_e, e^{-}) ^{180}Ta, are calculated by the standard Quasi-particle Random Phase Approximation (QRPA) with neutron-proton pairing as well as neutron-neutron, proton-proton pairing correlations. For neutral current (NC) reactions, 139^{139}La(νν)139 (\nu \nu^{'}) ^{139}{La}^* and 181^{181}Ta(ν,ν)181 (\nu, \nu^{'}) ^{181}Ta^*, we generate ground and excited states of odd-even target nuclei, 139^{139}La and 181^{181}Ta, by operating one quasi-particle to even-even nuclei, 138^{138}Ba and 180^{180}Hf, which are assumed as the BCS ground state. Numerical results for CC reactions are shown to be consistent with recent semi-empirical data deduced from the Gamow-Teller strength distributions measured in the (3^{3}He, t) reaction. Results for NC reactions are estimated to be smaller by a factor about 4 \sim 5 rather than those by CC reactions. Finally, cross sections weighted by the incident neutrino flux in the core collapsing supernova are presented for further applications to the network calculations for relevant nuclear abundances

    MaRMI-III: a methodology for component-based development

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    This study, supported by the Korea Ministry of Information and Communication, contributed to advancing the paradigm of software component-based development by developing a detailed process, techniques, and guidelines for making the most of component technologies. The outcome was a new CBD methodology named Magic and Robust Methodology Integrated III (MaRMI-III). MaRMI-III is now considered as a standard development methodology for using component technologies in Korea. To date, more than 100 Korean software development companies have adopted the methodology developed in this study

    Test code for the assessment and improvement of Reynolds stress models

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    An existing two-dimensional, compressible flow, Navier-Stokes computer code, containing a full Reynolds stress turbulence model, was adapted for use as a test bed for assessing and improving turbulence models based on turbulence simulation experiments. To date, the results of using the code in comparison with simulated channel flow and over an oscillating flat plate have shown that the turbulence model used in the code needs improvement for these flows. It is also shown that direct simulation of turbulent flows over a range of Reynolds numbers are needed to guide subsequent improvement of turbulence models

    Green Function of the Sutherland Model with SU(2) internal symmetry

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    We obtain the hole propagator of the Sutherland model with SU(2) internal symmetry for coupling parameter β=1\beta=1, which is the simplest nontrivial case. One created hole with spin down breaks into two quasiholes with spin down and one quasihole with spin up. While these elementary excitations are energetically free, the form factor reflects their anyonic character. The expression for arbitrary integer β\beta is conjectured.Comment: 13pages, Revtex, one ps figur

    Finite Size Polyelectrolyte Bundles at Thermodynamic Equilibrium

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    We present the results of extensive computer simulations performed on solutions of monodisperse charged rod-like polyelectrolytes in the presence of trivalent counterions. To overcome energy barriers we used a combination of parallel tempering and hybrid Monte Carlo techniques. Our results show that for small values of the electrostatic interaction the solution mostly consists of dispersed single rods. The potential of mean force between the polyelectrolyte monomers yields an attractive interaction at short distances. For a range of larger values of the Bjerrum length, we find finite size polyelectrolyte bundles at thermodynamic equilibrium. Further increase of the Bjerrum length eventually leads to phase separation and precipitation. We discuss the origin of the observed thermodynamic stability of the finite size aggregates

    Cosmology in a brane-universe

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    This contribution presents the cosmological models with extra dimensions that have been recently elaborated, which assume that ordinary matter is confined on a surface, called brane, embedded in a higher dimensional spacetime.Comment: 12 pages; Invited review talk at the JENAM 2002 workshop on "The cosmology of extra dimensions and varying fundamental constants", Porto, Portugal, September 200

    Diffusion-limited loop formation of semiflexible polymers: Kramers theory and the intertwined time scales of chain relaxation and closing

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    We show that Kramers rate theory gives a straightforward, accurate estimate of the closing time τc\tau_c of a semiflexible polymer that is valid in cases of physical interest. The calculation also reveals how the time scales of chain relaxation and closing are intertwined, illuminating an apparent conflict between two ways of calculating τc\tau_c in the flexible limit.Comment: Europhys. Lett., 2003 (in press). 8 pages, 3 figures. See also, physics/0101087 for physicist's approach to and the importance of semiflexible polymer looping, in DNA replicatio
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