60 research outputs found

    Evidence for the classical integrability of the complete AdS(4) x CP(3) superstring

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    We construct a zero-curvature Lax connection in a sub-sector of the superstring theory on AdS(4) x CP(3) which is not described by the OSp(6|4)/U(3) x SO(1,3) supercoset sigma-model. In this sub-sector worldsheet fermions associated to eight broken supersymmetries of the type IIA background are physical fields. As such, the prescription for the construction of the Lax connection based on the Z_4-automorphism of the isometry superalgebra OSp(6|4) does not do the job. So, to construct the Lax connection we have used an alternative method which nevertheless relies on the isometry of the target superspace and kappa-symmetry of the Green-Schwarz superstring.Comment: 1+26 pages; v2: minor typos corrected, acknowledgements adde

    Imports, unionization and racial age discrimination in the US

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    Past studies of the relationship between competition and racial wages find that domestic competition reduces racial wage discrimination of nonunion workers. This article examines the effects of foreign competition on racial wages of union and nonunion workers utilizing an empirical model which allows for cluster-adjusted SEs by industry. Such a procedure allows independence of observations across industries but not within industries, thereby not overstating the significance of industry invariant controls. In this analysis, clustered SEs prevent the overstatement of the significance of imports as a means to reduce earnings discrimination. We find evidence of a wage premium for nonunion white workers in concentrated industries; however, imports cause the wages of nonunion whites to converge towards market rates. In contrast, for union workers in concentrated industries, wage standardization provides a sanctuary from market power initiated discrimination such that imports play a limited role in reducing discrimination

    Use of health services by remote dwelling Aboriginal infants in tropical northern Australia: a retrospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>Australia is a wealthy developed country. However, there are significant disparities in health outcomes for Aboriginal infants compared with other Australian infants. Health outcomes tend to be worse for those living in remote areas. Little is known about the health service utilisation patterns of remote dwelling Aboriginal infants. This study describes health service utilisation patterns at the primary and referral level by remote dwelling Aboriginal infants from northern Australia.</p> <p>Results</p> <p>Data on 413 infants were analysed. Following birth, one third of infants were admitted to the regional hospital neonatal nursery, primarily for preterm birth. Once home, most (98%) health service utilisation occurred at the remote primary health centre, infants presented to the centre about once a fortnight (mean 28 presentations per year, 95%CI 26.4-30.0). Half of the presentations were for new problems, most commonly for respiratory, skin and gastrointestinal symptoms. Remaining presentations were for reviews or routine health service provision. By one year of age 59% of infants were admitted to hospital at least once, the rate of hospitalisation per infant year was 1.1 (95%CI 0.9-1.2).</p> <p>Conclusions</p> <p>The hospitalisation rate is high and admissions commence early in life, visits to the remote primary health centre are frequent. Half of all presentations are for new problems. These findings have important implications for health service planning and delivery to remote dwelling Aboriginal families.</p

    International Financial Aggregation and Index Number Theory: A Chronological Half-Century Empirical Overview

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    This paper comprises a survey of a half century of research on international monetary aggregate data. We argue that since monetary assets began yielding interest, the simple sum monetary aggregates have had no foundations in economic theory and have sequentially produced one source of misunderstanding after another. The bad data produced by simple sum aggregation have contaminated research in monetary economics, have resulted in needless “paradoxes,” and have produced decades of misunderstandings in international monetary economics research and policy. While better data, based correctly on index number theory and aggregation theory, now exist, the official central bank data most commonly used have not improved in most parts of the world. While aggregation theoretic monetary aggregates exist for internal use at the European Central Bank, the Bank of Japan, and many other central banks throughout the world, the only central banks that currently make aggregation theoretic monetary aggregates available to the public are the Bank of England and the St. Louis Federal Reserve Bank. No other area of economics has been so seriously damaged by data unrelated to valid index number and aggregation theory. In this paper we chronologically review the past research in this area and connect the data errors with the resulting policy and inference errors. Future research on monetary aggregation and policy can most advantageously focus on extensions to exchange rate risk and its implications for multilateral aggregation over monetary asset portfolios containing assets denominated in more than one currency. The relevant theory for multilateral aggregation with exchange rate risk has been derived by Barnett (2007) and Barnett and Wu (2005)

    Heteroskedasticity

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