47,655 research outputs found

    Class-based Rough Approximation with Dominance Principle

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    Dominance-based Rough Set Approach (DRSA), as the extension of Pawlak's Rough Set theory, is effective and fundamentally important in Multiple Criteria Decision Analysis (MCDA). In previous DRSA models, the definitions of the upper and lower approximations are preserving the class unions rather than the singleton class. In this paper, we propose a new Class-based Rough Approximation with respect to a series of previous DRSA models, including Classical DRSA model, VC-DRSA model and VP-DRSA model. In addition, the new class-based reducts are investigated.Comment: Submitted to IEEE-GrC201

    Increasing Kenya's Agricultural Competitiveness: Farm Level Issues

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    The objective of this paper is to address the farm level issues that affect the production costs and so the competitiveness of domestic food and commercial production. It compares domestic production prices of key food commodities with the equivalent parity prices to assess the extent to which the domestic prices for maize, wheat, and sugar, and export and domestic crops are competitive. This paper identifies and assesses the factors that influence domestic production costs. It also identifies strategies that could increase food and export crops’ productivity, by that reducing production costs and encourage competitiveness of the domestic production.Food Security, Food Policy, Kenya, Maize, Wheat, Sugar, Marketing, Q18,

    Rarefied flow past a flat plate at incidence

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    Results of a numerical study using the direct simulation Monte Carlo (DSMC) method are presented for the transitional flow about a flat plate at 40 deg incidence. The plate has zero thickness and a length of 1.0 m. The flow conditions simulated are those experienced by the Shuttle Orbiter during reentry at 7.5 km/s. The range of freestream conditions are such that the freestream Knudsen number values are between 0.02 and 8.4, i.e., conditions that encompass most of the transitional flow regime. The DSMC simulations show that transitional effects are evident when compared with free molecule results for all cases considered. The calculated results demonstrate clearly the necessity of having a means of identifying the effects of transitional flow when making aerodynamic flight measurements as are currently being made with the Space Shuttle Orbiter vehicles. Previous flight data analyses have relied exclusively on adjustments in the gas-surface interaction models without accounting for the transitional effect which can be comparable in magnitude. The present calculations show that the transitional effect at 175 km would increase the Space Shuttle Orbiter lift-drag ratio by 90 percent over the free molecule value

    Quark confinement and color transparency in a gauge-invariant formulation of QCD

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    We examine a nonlocal interaction that results from expressing the QCD Hamiltonian entirely in terms of gauge-invariant quark and gluon fields. The interaction couples one quark color-charge density to another, much as electric charge densities are coupled to each other by the Coulomb interaction in QED. In QCD, this nonlocal interaction also couples quark color-charge densities to gluonic color. We show how the leading part of the interaction between quark color-charge densities vanishes when the participating quarks are in a color singlet configuration, and that, for singlet configurations, the residual interaction weakens as the size of a packet of quarks shrinks. Because of this effect, color-singlet packets of quarks should experience final state interactions that increase in strength as these packets expand in size. For the case of an SU(2) model of QCD based on the {\em ansatz} that the gauge-invariant gauge field is a hedgehog configuration, we show how the infinite series that represents the nonlocal interaction between quark color-charge densities can be evaluated nonperturbatively, without expanding it term-by-term. We discuss the implications of this model for QCD with SU(3) color and a gauge-invariant gauge field determined by QCD dynamics.Comment: Revtex, 23 pages; contains additional references with brief comments on sam

    The basic chemistry of exercise-induced DNA oxidation:oxidative damage, redox signalling and their interplay

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    Acute exercise increases reactive oxygen and nitrogen species generation. This phenomenon is associated with two major outcomes: (1) redox signalling and (2) macromolecule damage. Mechanistic knowledge of how exercise-induced redox signalling and macromolecule damage are interlinked is limited. This review focuses on the interplay between exercise-induced redox signalling and DNA damage, using hydroxyl radical (·OH) and hydrogen peroxide (H2O2) as exemplars. It is postulated that the biological fate of H2O2 links the two processes and thus represents a bifurcation point between redox signalling and damage. Indeed, H2O2 can participate in two electron signalling reactions but its diffusion and chemical properties permit DNA oxidation following reaction with transition metals and ·OH generation. It is also considered that the sensing of DNA oxidation by repair proteins constitutes a non-canonical redox signalling mechanism. Further layers of interaction are provided by the redox regulation of DNA repair proteins and their capacity to modulate intracellular H2O2 levels. Overall, exercise-induced redox signalling and DNA damage may be interlinked to a greater extent than was previously thought but this requires further investigation

    Disparities in Hospital Services Utilization Among Patients with Mental Health Issues: A Statewide Example Examining Insurance Status and Race Factors from 1999-2010

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    There exist many disconnects between the mental and general health care sectors. However, a goal of the Affordable Care Act (ACA) of 2010 is to change this by improving insurance access and the intersection of mental and general health care. As insurance status intersects with race, the present study examines how race, insurance status, and hospital mental health services utilization differ across groups within the state of New Jersey. The present study aims to determine trends in hospital mental health care utilization by insurance status and race from 1999 to 2010. The rate of self-pay for mental health disorders in the Black population was significantly higher than the rate for Whites and Asians during this period. However, though Asian mental health utilization increased the most over the 11-year period, the Asian population had the slowest growth in self-pay rates. ANOVA tests demonstrated significant differences in the rate of self-pay mental health cases between race groups (
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