27,889 research outputs found

    High statistics calculations of quenched QCD spectrum using various quark sources

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    We present the results for the hadron spectrum calculated on 400 configurations using point source, wall source and 8-cubic sources, in quenched QCD with Wilson fermions at β=6.0\beta=6.0 and K=0.155K=0.155 on a 243×5424^3 \times 54 lattice. The results for the ground state masses obtained with three types of quark sources agree well with each other. Masses of the first excited states appear consistent with experimental values within large errors.Comment: 3 pages, 2 postscript figures, to appear in the Proceedings of LATTICE 93, Dallas, USA; preprint UTHEP-26

    LANDSAT menhaden and thread herring resources investigation

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    The author has identified the following significant results. The relationship between the distribution of menhaden and selected oceanographic parameters (water color, turbidity, and possibly chlorophyll concentrations) was established. Similar relationships for thread herring were not established nor were relationships relating to the abundance of either species. Use of aircraft and LANDSAT remote sensing instruments to measure or infer a set of basic oceanographic parameters was evaluated. Parameters which could be accurately inferred included surface water temperature, salinity, and color. Water turbidity (Secchi disk) was evaluated as marginally inferrable from the LANDSAT MSS data and chlorophyll-a concentrations as less than marginal. These evaluations considered the parameters only as experienced in the two test areas using available sensors and statistical techniques

    Periodic Optical Variability of Radio Detected Ultracool Dwarfs

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    A fraction of very low mass stars and brown dwarfs are known to be radio active, in some cases producing periodic pulses. Extensive studies of two such objects have also revealed optical periodic variability and the nature of this variability remains unclear. Here we report on multi-epoch optical photometric monitoring of six radio detected dwarfs, spanning the \simM8 - L3.5 spectral range, conducted to investigate the ubiquity of periodic optical variability in radio detected ultracool dwarfs. This survey is the most sensitive ground-based study carried out to date in search of periodic optical variability from late-type dwarfs, where we obtained 250 hours of monitoring, delivering photometric precision as low as \sim0.15%. Five of the six targets exhibit clear periodicity, in all cases likely associated with the rotation period of the dwarf, with a marginal detection found for the sixth. Our data points to a likely association between radio and optical periodic variability in late-M/early-L dwarfs, although the underlying physical cause of this correlation remains unclear. In one case, we have multiple epochs of monitoring of the archetype of pulsing radio dwarfs, the M9 TVLM 513-46546, spanning a period of 5 years, which is sufficiently stable in phase to allow us to establish a period of 1.95958 ±\pm 0.00005 hours. This phase stability may be associated with a large-scale stable magnetic field, further strengthening the correlation between radio activity and periodic optical variability. Finally, we find a tentative spin-orbit alignment of one component of the very low mass binary LP 349-25.Comment: Accepted to The Astrophysical Journal; 22 pages; 12 figure

    Lattice Gauge Theory -- Present Status

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    Lattice gauge theory is our primary tool for the study of non-perturbative phenomena in hadronic physics. In addition to giving quantitative information on confinement, the approach is yielding first principles calculations of hadronic spectra and matrix elements. After years of confusion, there has been significant recent progress in understanding issues of chiral symmetry on the lattice. (Talk presented at HADRON 93, Como, Italy, June 1993.)Comment: 11 pages, BNL-4946

    Time, institutional support and quality of decision making in child protection:A cross-country analysis

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    This paper examines perceptions of time and institutional support for decision making and staff confidence in child welfare staffs ultimate decisions – examining differences and similarities between and within the service-oriented Nordic countries (Norway and Finland) and the risk-oriented Anglo-American countries (England and California). The study identifies a high degree of work pressure across all the countries, lines of predominantly vertical institutional support and relatively high confidence in decisions. Finland stands out with higher perceived work pressure and with a horizontal support line, whereas England stands out with workers having a lower degree of confidence in their own and others’ decisions
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