34,832 research outputs found

    Discrete mechanics and variational integrators

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    This paper gives a review of integration algorithms for finite dimensional mechanical systems that are based on discrete variational principles. The variational technique gives a unified treatment of many symplectic schemes, including those of higher order, as well as a natural treatment of the discrete Noether theorem. The approach also allows us to include forces, dissipation and constraints in a natural way. Amongst the many specific schemes treated as examples, the Verlet, SHAKE, RATTLE, Newmark, and the symplectic partitioned Runge–Kutta schemes are presented

    Increasing EHR Use for Quality Improvement in Community Health Centers: The Role of Networks

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    Describes how five community health center networks helped implement electronic health records to improve chronic and preventive care, as well as the obstacles they faced, including limited software capabilities, funding, and ability to share resources

    What makes a good employer?

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    E_11 and M Theory

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    We argue that eleven dimensional supergravity can be described by a non-linear realisation based on the group E_{11}. This requires a formulation of eleven dimensional supergravity in which the gravitational degrees of freedom are described by two fields which are related by duality. We show the existence of such a description of gravity.Comment: 21 pages, some typos corrected and two references adde

    Duality Symmetries and G^{+++} Theories

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    We show that the non-linear realisations of all the very extended algebras G^{+++}, except the B and C series which we do not consider, contain fields corresponding to all possible duality symmetries of the on-shell degrees of freedom of these theories. This result also holds for G_2^{+++} and we argue that the non-linear realisation of this algebra accounts precisely for the form fields present in the corresponding supersymmetric theory. We also find a simple necessary condition for the roots to belong to a G^{+++} algebra.Comment: 35 pages. v2: 2 appendices added, other minor corrections. v3: tables corrected, other minor changes, one appendix added, refs. added. Version published in Class. Quant. Gra

    Profiling Consumer Trend-setters in the Canadian Healthy-foods Market

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    The agri-food industry faces new challenges as consumer demand for new, healthier foods increases. Media headlines frequently mention health benefits from certain foods and food components, and consumers are more health conscious because they are aging. They realize their food choices can reduce their risk of developing chronic illnesses such as cancer and heart disease. The competitive advantages for firms who are the first to bring their food innovations to market will depend in part on the efficacy of their marketing strategies. Firms that can identify and target those consumers who are most interested in trying new foods with enhanced functional health properties will likely be the most successful. This paper identifies attitudinal and sociodemographic characteristics that influence a consumer’s desire to be among the first to try innovative functional foods.Consumer/Household Economics, Health Economics and Policy, Marketing,

    Variational Multisymplectic Formulations of Nonsmooth Continuum Mechanics

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    This paper develops the foundations of the multisymplectic formulation of nonsmooth continuum mechanics. It may be regarded as a PDE generalization of previous techniques that developed a variational approach to collision problems. These methods have already proved of value in computational mechanics, particularly in the development of asynchronous integrators and efficient collision methods. The present formulation also includes solid-fluid interactions and material interfaces and, in addition, lays the groundwork for a treatment of shocks
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