3,970 research outputs found

    Finite type invariants of 3-manifolds

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    A theory of finite type invariants for arbitrary compact oriented 3-manifolds is proposed, and illustrated through many examples arising from both classical and quantum topology. The theory is seen to be highly non-trivial even for manifolds with large first betti number, encompassing much of the complexity of Ohtsuki's theory for homology spheres. (For example, it is seen that the quantum SO(3) invariants, though not of finite type, are determined by finite type invariants.) The algebraic structure of the set of all finite type invariants is investigated, along with a combinatorial model for the theory in terms of trivalent "Feynman diagrams".Comment: Final version for publication, with figures. The most significant changes from the original posted version are in the exposition of section 3 (on the Conway polynomial) and section 4 (on quantum invariants

    Biscayne aquifer in Dade and Broward Counties, Florida

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    The Biscayne Aquifer is the principal source of water for the heavily populated area in the vicinity of West Palm Beach and Miami. The publication of this data is timely and will assist in the intelligent development of the water resources of the area.(PDF has 64 pages

    A RANGELAND GRASSHOPPER INSURANCE PROGRAM

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    The incidence of benefits and costs from controlling rangeland grasshoppers on public grazing lands poses problems of economic efficiency and distributional equity. Public grasshopper control programs operate like public disaster assistance. However, grasshopper infestations are an insurable risk. This article proposes a rangeland grasshopper insurance program which reduces the economic inefficiencies and distributional inequities of the existing program.Risk and Uncertainty,

    A Discrete Theory of Connections on Principal Bundles

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    Connections on principal bundles play a fundamental role in expressing the equations of motion for mechanical systems with symmetry in an intrinsic fashion. A discrete theory of connections on principal bundles is constructed by introducing the discrete analogue of the Atiyah sequence, with a connection corresponding to the choice of a splitting of the short exact sequence. Equivalent representations of a discrete connection are considered, and an extension of the pair groupoid composition, that takes into account the principal bundle structure, is introduced. Computational issues, such as the order of approximation, are also addressed. Discrete connections provide an intrinsic method for introducing coordinates on the reduced space for discrete mechanics, and provide the necessary discrete geometry to introduce more general discrete symmetry reduction. In addition, discrete analogues of the Levi-Civita connection, and its curvature, are introduced by using the machinery of discrete exterior calculus, and discrete connections.Comment: 38 pages, 11 figures. Fixed labels in figure

    \u3ci\u3eIxodes Dentatus\u3c/i\u3e (Acari: Ixodidae) in Michigan: First State Records and Occurrence on a Human

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    An Ixodes dentatus adult female was taken from a cottontail rabbit in Kalamazoo County, and a nymph from a child in Berrien County, in 1992 in Michigan. These findings represent the first records of I.dentatus in the state, and document an unusual parasitization of a human being by this species of tick

    Interview of Melvin D. Shipp by Robert Newcomb

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    Interview conducted at The Ohio State University Archives, Columbus, Ohio.Dr. Melvin D. Shipp describes his career at OSU’s College of Optometry, culminating in his role as Dean. Shipp was born in 1948, and because of his father’s military career, he moved a great deal as a child, including Germany where he graduated from high school. Shipp subsequently attended Indiana University to earn his bachelor’s degree, and he decided to stay there to earn a graduate degree in optometry. During his fourth year in graduate school, he worked with Dr. John Amos designing lab exercises for a course, which spurred Shipp to go into academic optometry. Shipp then served in the Navy as an optometrist for four years. After his active duty ended, he decided to pursue a graduate degree in public health, and he chose a university where he could also practice. He remained at the University of Alabama at Birmingham there for 25 years. He was subsequently asked to apply for the position of Dean at OSU’s College of Optometry, and he served in this position from 2004 through 2014. Shipp describes the College’s achievements during his tenure and the people who helped him lead those efforts. He also discusses his tenure as the first optometrist to lead the American Public Health Association and his view of what the profession of optometry might look like in the future

    Words From the Journey

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