19,049 research outputs found

    Excitations of the ν=5/2\nu=5/2 Fractional Quantum Hall State and the Generalized Composite Fermion Picture

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    We present a generalization of the composite Fermion picture for a muticomponent quantum Hall plasma which contains particle with different effective charges. The model predicts very well the low-lying states of a ν=5/2\nu=5/2 quantum Hall state found in numerical diagonalization.Comment: 5 pages, 3 figure

    Changes in the Structure of Wages During the 1980's: An Evaluation of Alternative Explanations

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    Between 1979 and 1987 there were three significant changes in the wage structure in the United States. the pecuniary returns to schooling increased by about a third; the wages of older relative to younger workers with relatively low education increased to some extent; and the wages of women relative to men rose by almost ten percent. It is important for policy purposes to know why these changes occurred and whether they are temporary or permanent. The paper investigates several alternative explanations of these wage structure phenomena, including the most popular ones that their principal causes were shifts in the structure of product demand, skilled-labor saving technological change, and changes in the incidence and level of rents received by lower skilled workers. our reading of the evidence suggests that the major cause of the dramatic movements in the wage structure during the 1980's may have been some combination of changes in both production technology and the average relative nonobserved quality of different labor groups.

    One year of monitoring the Vela pulsar using a Phased Array Feed

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    We have observed the Vela pulsar for one year using a Phased Array Feed (PAF) receiver on the 12-metre antenna of the Parkes Test-Bed Facility. These observations have allowed us to investigate the stability of the PAF beam-weights over time, to demonstrate that pulsars can be timed over long periods using PAF technology and to detect and study the most recent glitch event that occurred on 12 December 2016. The beam-weights are shown to be stable to 1% on time scales on the order of three weeks. We discuss the implications of this for monitoring pulsars using PAFs on single dish telescopes.Comment: 6 pages, 4 figures, 2 tables. Accepted for publication in PAS

    Factorization is not violated

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    We show that existing proofs of factorization imply the cancellation of certain multiladder contributions that Gotsman, Levin, and Maor had suggested would invalidate the basic factorization theorem in QCD. No modifications of the original argument are necessary, although the details of the example offer useful insight into the mechanisms of factorization.Comment: 11 pages including 10 figure

    The Urban Growth Question

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    Selective Oxidation of sp^3 C-H Bonds in Water Catalyzed by a Glycinate-Platinum(II) Complex

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    In aqueous solution, [Pt^(II)(glycinato)Cl_2]^− catalyzes oxidation by [Pt^(IV)Cl_6]^(2−) of the methyl group of p-toluenesulfonate to the corresponding alcohol and aldehyde, with no further oxidation to the carboxylic acid. Both rate and selectivity are improved in comparison to the original Shilov system that employs [Pt^(II)Cl_n(H_2O)_(4−n)]^(2−n) as the catalyst

    Making a difference - the appropriate use of web technology

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    Much has been written elsewhere about how, different Information Technology tools, can in principle be used by groups or communities to make their web sites more effective for Continued Professional Development. In practice, complex use is not often the case. In particular, three sites were studied in Scotland, which provided web facilities for the over 60s. The sites, and the communities they served, used only simple Information Technology. Nevertheless, they enabled their communities to participate effectively, on the 'right side', of the European population's 'digital divide'

    Celecoxib concentration predicts decrease in prostaglandin E\u3csub\u3e2\u3c/sub\u3e concentrations in nipple aspirate fluid from high risk women

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    BACKGROUND: Epidemiologic studies suggest that long term low dose celecoxib use significantly lowers breast cancer risk. We previously demonstrated that 400 mg celecoxib taken twice daily for 2 weeks lowered circulating plasma and breast nipple aspirate fluid (NAF) prostaglandin (PG)E2 concentrations in post- but not premenopausal high risk women. We hypothesized that circulating concentrations of celecoxib influenced PGE2 response, and that plasma levels of the drug are influenced by menopausal status. To address these hypotheses, the aims of the study were to determine: 1) if circulating plasma concentrations of celecoxib correlated with the change in plasma or NAF PGE2 concentrations from baseline to end of treatment, and 2) whether menopausal status influenced circulating levels of celecoxib. METHODS: Matched NAF and plasma were collected from 46 high risk women who were administered celecoxib twice daily for two weeks, 20 subjects receiving 200 mg and 26 subjects 400 mg of the agent. NAF and plasma samples were collected before and 2 weeks after taking celecoxib. RESULTS: In women taking 400 mg bid celecoxib, plasma concentrations of the agent correlated inversely with the change in NAF PGE2 levels from pre- to posttreatment. Nonsignificant trends toward higher celecoxib levels were observed in post- compared to premenopausal women. There was a significant decrease in NAF but not plasma PGE2 concentrations in postmenopausal women who took 400 mg celecoxib (p = 0.03). CONCLUSION: In high risk women taking 400 mg celecoxib twice daily, plasma concentrations of celecoxib correlated with downregulation of PGE2 production by breast tissue. Strategies synergistic with celecoxib to downregulate PGE2 are of interest, in order to minimize the celecoxib dose required to have an effect
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