28,597 research outputs found

    Exterior splashes and linear sets of rank 3

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    In \PG(2,q^3), let π\pi be a subplane of order qq that is exterior to \li. The exterior splash of π\pi is defined to be the set of q2+q+1q^2+q+1 points on \li that lie on a line of π\pi. This article investigates properties of an exterior \orsp\ and its exterior splash. We show that the following objects are projectively equivalent: exterior splashes, covers of the circle geometry CG(3,q)CG(3,q), Sherk surfaces of size q2+q+1q^2+q+1, and \GF(q)-linear sets of rank 3 and size q2+q+1q^2+q+1. We compare our construction of exterior splashes with the projection construction of a linear set. We give a geometric construction of the two different families of sublines in an exterior splash, and compare them to the known families of sublines in a scattered linear set of rank 3

    The tangent splash in \PG(6,q)

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    Let B be a subplane of PG(2,q^3) of order q that is tangent to ℓ∞\ell_\infty. Then the tangent splash of B is defined to be the set of q^2+1 points of ℓ∞\ell_\infty that lie on a line of B. In the Bruck-Bose representation of PG(2,q^3) in PG(6,q), we investigate the interaction between the ruled surface corresponding to B and the planes corresponding to the tangent splash of B. We then give a geometric construction of the unique order-qq-subplane determined by a given tangent splash and a fixed order-qq-subline.Comment: arXiv admin note: substantial text overlap with arXiv:1303.550

    Spin-Selective Transport of Electron in DNA Double Helix

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    The experiment that the high spin selectivity and the length-dependent spin polarization are observed in double-stranded DNA [Science 331{\bf 331}, 894 (2011)], is elucidated by considering the combination of the spin-orbit coupling, the environment-induced dephasing, and the helical symmetry. We show that the spin polarization in double-stranded DNA is significant even in the case of weak spin-orbit coupling, while no spin polarization appears in single-stranded DNA. Furthermore, the underlying physical mechanism and the parameters-dependence of the spin polarization are studied.Comment: 5 pages; 4 figure

    Construction of nested space-filling designs

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    New types of designs called nested space-filling designs have been proposed for conducting multiple computer experiments with different levels of accuracy. In this article, we develop several approaches to constructing such designs. The development of these methods also leads to the introduction of several new discrete mathematics concepts, including nested orthogonal arrays and nested difference matrices.Comment: Published in at http://dx.doi.org/10.1214/09-AOS690 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Factors Influencing the Purchase of Live Seafood in the North Central Region of the United States

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    This study assesses the preferences of shoppers of live seafood products in the North Central Region of the US accounting for heterogeneity in their preferences. The results suggest that quality assurance considerations and high incomes are factors that would increase the probability of higher expenditures on live fish/shellfish. The purchase of saltwater fish and shellfish also increased the probability of higher expenditures. The North Central Region produces freshwater seafood, and maintaining fish quality through the production process is important to this niche market. Shoppers also purchased live seafood frequently, signifying the importance of availability.Live fish, preferences, random parameters ordered probit, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Institutional and Behavioral Economics, Public Economics, Q11, Q21, Q22,
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