70,951 research outputs found

    The Effective Potential And Additional Large Radius Compactified Space-Time Dimensions

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    The consequences of large radius extra space-time compactified dimensions on the four dimensional one loop effective potential are investigated for a model which includes scalar self interactions and Yukawa coupling to fermions. The Kaluza-Klein tower of states associated with the extra compact dimensions shifts the location of the effective potential minimum and modifies its curvature. The dependence of these effects on the radius of the extra dimension is illustrated for various choices of coupling constants and masses. For large radii, the consequence of twisting the fermion boundary condition on the compactified dimensions is numerically found to produce but a negligible effect on the effective potential.Comment: 14 pages, LaTeX, 6 Postscript figure

    The government's child poverty target: how much progress has been made?

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    Before the 2001 election the Treasury said that `tax and benefit reforms announced in this Parliament will lift over 1.2 million children out of relative poverty'. But official figures released on 11 April show a smaller fall in child poverty, of only 0.5 million since 1996-97. This commentary attempts to explain the discrepancy. Using the data that lie behind the official Households Below Average Income publications, we analyse trend in child poverty, measured against various poverty lines, since 1979. We show how the government's choice of a relative poverty line is making its goal to abolish child poverty more difficult and more expensive. We also discuss how easy the government will find it to make further reductions in child poverty

    The Akulov-Volkov Lagrangian, Symmetry Currents and Spontaneously Broken Extended Supersymmetry

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    A generalization of the Akulov-Volkov effective Lagrangian governing the self interactions of the Nambu-Goldstone fermions associated with spontaneously broken extended supersymmetry as well as their coupling to matter is presented and scrutinized. The resulting currents associated with R-symmetry, supersymmetry and space-time translations are constructed and seen to form a supermultiplet structure.Comment: 17 pages, LaTeX; Title, abstract and introduction changes, references adde

    Deformations in VLBI antennas

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    A study is presented of deformations in antennas with the emphasis on their influence on VLBI measurements. The GIFTS structural analysis program has been used to model the VLBI antenna in Fairbanks (Alaska). The report identifies key deformations and studies the effect of gravity, wind, and temperature. Estimates of expected deformations are given

    Compatibility of potential reinforcing ceramics with Ni and Fe aluminides

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    There is a great deal of interest in the possible utilization of intermetallic compounds in advanced high temperature gas turbine engines. These compounds exhibit a variety of promising properties, including reasonable strength, high melting points, relatively low densities, and good corrosion resistance. However, in general, they also show limited ductilities and toughness, and less than optimum creep strengths at elevated temperatures. In addition, in applications involving advanced gas turbine engines, it is often necessary for candidate materials to have large elastic moduli. The present study is part of a program whose objective is to identify a high temperature fiber reinforced composite. The approach adopted was to fabricate laboratory samples of the combinations of materials considered by Misra, in order to determine the extent to which the thermodynamic calculations can predict phase stability. As many of the ceramic phases considered are not currently available in fiber form, they were added as particulates to the alloy matrices. The ways in which the materials were produced and evaluated are described

    Worldwide time and frequency synchronization by planned VLBI networks

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    Accurate baseline determinations and clock synchronization results obtained from the Quasar Patrol observations at X band with the Goldstone-Haystack baseline are presented. In addition, data from stations at Greenbank, West Virginia, and Onsala, Sweden were used. It was estimated that clock accuracy was on the order of 16 cm

    Time, geodesy, and astrometry: Results from radio interferometry

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    The results from a total of a dozen transcontinental and intercontinental VLBI experiments are discussed. Particular emphasis is placed on: (1) the inferred behavior of the frequency standards, usually hydrogen masers, on time scales from 10 to 100,000 seconds; (2) the estimated celestial positions of the observed radio sources; (3) the determinations of the vector baselines; and (4) the inferred values of polar motion and UT.1

    Diamond-Like Carbon film from Liquid Gas on Metallic Substrates

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    Liquid gas was used to produce DLC films on Cu, Al and steel substrates by DC plasma technique. The absorption in IR reflectance indicates, grown films are DLC. By deconvolution of room temperature UV-visible spectra of the films grown at 50 mtorr and 200∘{}^\circC, in addition to the spectra lines reported for CL, PL, PLC and ESR, some new spectra lines were obtained. We also, have seen exciton absorption line at room temperature.Comment: 6 pages, Postscript, 2 figure
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