31,175 research outputs found

    Microscopes and computers combined for analysis of chromosomes

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    Scanning machine CHLOE, developed for photographic use, is combined with a digital computer to obtain quantitative and statistically significant data on chromosome shapes, distribution, density, and pairing. CHLOE permits data acquisition about a chromosome complement to be obtained two times faster than by manual pairing

    A note on log-convexity of q-Catalan numbers

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    The q-Catalan numbers studied by Carlitz and Riordan are polynomials in q with nonnegative coefficients. They evaluate, at q=1, to the Catalan numbers: 1, 1, 2, 5, 14,..., a log-convex sequence. We use a combinatorial interpretation of these polynomials to prove a q-log-convexity result. The sequence of q-Catalan numbers is not q-log-convex in the narrow sense used by other authors, so our work suggests a more flexible definition of q-log convex be adopted

    Spin Dependent Tunneling in FM|semiconductor|FM structures

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    Here we show that ordinary band structure codes can be used to understand the mechanisms of coherent spin-injection at interfaces between ferromagnets and semiconductors. This approach allows the screening of different material combinations for properties useful for obtaining high tunneling magnetoresistance (TMR). We used the Vienna Ab-initio Simulation Code (VASP) to calculate the wave function character of each band in periodic epitaxial Fe(100)|GaAs(100) and Fe(100)|ZnSe(100) structures. It is shown that Fe wave functions of different symmetry near Fermi energy decay differently in the GaAs and ZnSe.Comment: Accepted for publication in MMM'05 Proceedings. 7 pages, 5 figure

    The structural response of unsymmetrically laminated composite cylinders

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    The responses of an unsymmetrically laminated fiber-reinforced composite cylinder to an axial compressive load, a torsional load, and the temperature change associated with cooling from the processing temperature to the service temperature are investigated. These problems are considered axisymmetric and the response is studied in the context of linear elastic material behavior and geometrically linear kinematics. Four different laminates are studied: a general unsymmetric laminate; two unsymmetric but more conventional laminates; and a conventional quasi-isotropic symmetric laminate. The responses based on closed-form solutions for different boundary conditions are computed and studied in detail. Particular emphasis is directed at understanding the influence of elastic couplings in the laminates. The influence of coupling decreased from a large effect in the general unsymmetric laminate, to practically no effect in the quasi-isotropic laminate. For example, the torsional loading of the general unsymmetric laminate resulted in a radial displacement. The temperature change also caused a significant radial displacement to occur near the ends of the cylinder. On the other hand, the more conventional unsymmetric laminate and the quasi-isotropic cylinder did not deform radially when subjected to a torsional load. From the results obtained, it is clear the degree of elastic coupling can be controlled and indeed designed into a cylinder, the degree and character of the coupling being dictated by the application

    Pathways to Economic Mobility: Key Indicators

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    Outlines how indicators of social, human, and financial capital affect an individual's chances of moving up or down the economic ladder. Analyzes data on family structure, community, education, race/ethnicity, health, home ownership, and other factors

    Protective telescoping shield for solar concentrator

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    An apparatus is described for use with a solar concentrator such as a parabolic dish which concentrates sunlight onto a small opening of a solar receiver, for protecting the receiver in the event of a system failure that could cause concentrated sunlight to damage the receiver. The protective apparatus includes a structure which can be moved to a stowed position where it does not block sunlight, to a deployed position. In this position, the structure forms a tube which substantially completely surrounds an axis connecting the receiver opening to the center of the concentrator at locations between the receiver and the concentrator

    O Happy Day : With Brilliant Variations

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    https://digitalcommons.library.umaine.edu/mmb-ps/1850/thumbnail.jp

    Scottish Band March

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    Title Onlyhttps://scholarsjunction.msstate.edu/cht-sheet-music/11266/thumbnail.jp

    Neutrino Physics and Nuclear Axial Two-Body Interactions

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    We consider the counter-term describing isoscalar axial two-body currents in the nucleon-nucleon interaction, L1A, in the effective field theory approach. We determine this quantity using the solar neutrino data. We investigate the variation of L1A when different sets of data are used.Comment: 8 pages with 4 figures. To be published in the Proceedings of the Conference "Blueprints For The Nucleus: From First Principles to Collective Motion" held at Feza Gursey Institute, Istanbul, Turkey; May 17 -22, 200
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