35,736 research outputs found

    On Birch and Swinnerton-Dyer's cubic surfaces

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    In a 1975 paper of Birch and Swinnerton-Dyer, a number of explicit norm form cubic surfaces are shown to fail the Hasse Principle. They make a correspondence between this failure and the Brauer--Manin obstruction, recently discovered by Manin. We generalize their work, making use of modern computer algebra software to show that a larger set of cubic surfaces have a Brauer--Manin obstruction to the Hasse principle, thus verifying the Colliot-Th\'el\`ene--Sansuc conjecture for infinitely many cubic surfaces

    Analytic Metaphysics versus Naturalized Metaphysics: The Relevance of Applied Ontology

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    The relevance of analytic metaphysics has come under criticism: Ladyman & Ross, for instance, have suggested do discontinue the field. French & McKenzie have argued in defense of analytic metaphysics that it develops tools that could turn out to be useful for philosophy of physics. In this article, we show first that this heuristic defense of metaphysics can be extended to the scientific field of applied ontology, which uses constructs from analytic metaphysics. Second, we elaborate on a parallel by French & McKenzie between mathematics and metaphysics to show that the whole field of analytic metaphysics, being useful not only for philosophy but also for science, should continue to exist as a largely autonomous field

    An Outcome Comparison on the Use of Mckenzie Technique with and without Mulligan Mobilizations on the Treatment of Low Back Derangement

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    Effective research and outcome studies are currently lacking evidence to support the use and reimbursement of manual therapy interventions such as McKenzie techniques and Mulligan mobilizations. The purpose of this study was to compare the cost-effectiveness, efficiency, and outcomes of McKenzie techniques and McKenzie techniques with Mulligan mobilization on the treatment of patients with low back derangement through performing a chart review. Twenty-two subjects with a diagnosis of low back derangement were included in this study with sixteen subjects in the McKenzie group and six subjects in the McKenzie with Mulligan mobilizations group. An independent sample T -test showed no significant difference for age, total treatment costs, average cost per PT treatment, duration of PT services, number of PT treatments, initial and final pain level ratings, number of modalities used, initial and final ADL abilities, and for initial and final functional abilities. Subjective rating of percent improvement was the only category indicating a significant difference between the intervention groups (p\u3c .05). Although there was only one indicator found to be significantly different, two major trends were observed: 1) the McKenzie group appeared to be more cost effective and efficient compared to the McKenzie with Mulligan mobilization group. 2) The McKenzie with Mulligan mobilization group averaged slightly lower pain ratings at discharge, significantly higher subjective percent improvement, and slightly higher ADL and functional ability scores at discharge

    Introduction to special section: Hawaii Scientific Drilling Project

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    Intraplate or "hot spot" volcanic island chains, exemplified by Hawaii, play an important role in plate tectonic theory as reference points for absolute plate motions, but the origin of these volcanoes is not explained by the plate tectonic paradigm [Engebretson et al., 1985; Molnar and Stock, 1987; Morgan, 1971, 1981, 1983; Wilson, 1963]. The most widely held view is that these chains of volcanoes form from magma generated by decompression melting of localized, buoyant upwellings in the mantle [Ribe and Christensen, 1994; Richards et al., 1988; Sleep, 1990; Watson and McKenzie, 1991] . These upwellings, or "plumes," are believed to originate at boundary layers in the mantle (e.g., at the core-mantle boundary or near the boundary at-670 km between the upper and lower mantle), and the cause of the buoyancy may be both compositional and thermal [Campbell and Griffiths, 1990; Griffiths, 1986; Richards et al., 1988; Watson and McKenzie, 1991]. Mantle plumes are responsible for about 10% of the Earth's heat loss and constitute an important mechanism for cycling mass from the deep mantle to the Earth's surface. Studies of the chemical and isotopic compositions of lavas from intraplate volcanoes, especially ocean island volcanoes, have contributed significantly to our knowledge of magma genesis in the mantle [Carmichael et al., 1974; Macdonald et al., 1983] and the compositional heterogeneity of the mantle [Allègre et al., 1983; Hart, 1988; Hart et al., 1986; Kurz et al., 1983]. Of particular importance is the identification of distinct compositional end members in the mantle, the origin and distribution of which provide insight into the long-term differentiation of the mantle-crust system, the recycling of oceanic crust and continental sediment into the mantle, and the history of the lithosphere [Allègre et al., 1995; Farley et al., 1992; Hart, 1988; Hofmann and White, 1982; McKenzie and O'Nions, 1983; Weaver, 1991; Zindler and Hart, 1986]

    The McKenzie method for the management of acute non-specific low back pain: design of a randomised controlled trial [ACTRN012605000032651]

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    BACKGROUND: Low back pain (LBP) is a major health problem. Effective treatment of acute LBP is important because it prevents patients from developing chronic LBP, the stage of LBP that requires costly and more complex treatment. Physiotherapists commonly use a system of diagnosis and exercise prescription called the McKenzie Method to manage patients with LBP. However, there is insufficient evidence to support the use of the McKenzie Method for these patients. We have designed a randomised controlled trial to evaluate whether the addition of the McKenzie Method to general practitioner care results in better outcomes than general practitioner care alone for patients with acute LBP. METHODS/DESIGN: This paper describes the protocol for a trial examining the effects of the McKenzie Method in the treatment of acute non-specific LBP. One hundred and forty eight participants who present to general medical practitioners with a new episode of acute non-specific LBP will be randomised to receive general practitioner care or general practitioner care plus a program of care based on the McKenzie Method. The primary outcomes are average pain during week 1, pain at week 1 and 3 and global perceived effect at week 3. DISCUSSION: This trial will provide the first rigorous test of the effectiveness of the McKenzie Method for acute non-specific LBP

    The microeconomic determinants of emigration and return migration of the best and brightest: evidence from the Pacific

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    A unique survey which tracks worldwide the best and brightest academic performers from three Pacific countries is used to assess the extent of emigration and return migration among the very highly skilled, and to analyze, at the microeconomic level, the determinants of these migration choices. Although we estimate that the income gains from migration are very large, not everyone migrates and many return. Within this group of highly skilled individuals the emigration decision is found to be most strongly associated with preference variables such as risk aversion, patience, and choice of subjects in secondary school, and not strongly linked to either liquidity constraints or to the gain in income to be had from migrating. Likewise, the decision to return is strongly linked to family and lifestyle reasons, rather than to the income opportunities in different countries. Overall the data show a relatively limited role for income maximization in distinguishing migration propensities among the very highly skilled, and a need to pay more attention to other components of the utility maximization decision

    Apriorist self-interest: How it embraces altruism and is not vacuous

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    This essay is part of an attempt to reconcile two extreme views in economics: the (neglected) subjective, apriorist approach and the (standard) objective, scientific (i.e., falsifiable) approach. The Austrian subjective view of value, building on Carl Menger’s theory of value, was developed into a theory of economics as being entirely an a priori theory of action. This probably finds its most extreme statement in Ludwig von Mises’ Human Action (1949). In contrast, the standard economic view has developed into making falsifiable predictions about economic phenomena whereby the truth of the assumptions, especially about economic agents, is relatively unimportant: predictive fecundity is all. This finds an extreme statement in Milton Friedman’s introductory essay in his Essays in Positive Economics (1953). However, many economists fall somewhere between the two extremes, such as McKenzie and Tullock (1978)

    Report on status and trends of water quality and ecosystem health in the Great Barrier Reef World Heritage Area

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    Contributors: Rob Coles, Steve Delean, Miles Furnas, Len McKenzie, Munro Mortimer, Jochen Muller, Andrew Negri, Hugh Sweatman and Angus Thompson

    Do all networks facilitate international commerce? US law firms and the international market for corporate control

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    This paper estimates the effects of several American law firms' international networks of offices on the total value of overseas mergers and acquisitions (M&A) by US corporations. Nowadays many nations can review proposed mergers and US law firms help clients overcome such regulatory hurdles, effectively greasing the market for corporate control. However, they can also oppose transactions that are inimical to their clients' interests. I present evidence that suggests that Baker & McKenzie the US law firm with the most overseas offices has facilitated such transactions, whereas the combined effect of the next five largest American law firms has tended to reduce such M&A.
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