123,664 research outputs found

    Ligand design for site-selective installation of Pd and Pt centers to generate homo- and heteropolymetallic motifs

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    The modular synthesis of a series of nitrogen-rich polydentate ligands that feature a common pincer-type framework is reported. These ligands allow for site-selective installation of palladium and platinum to give rise to bi- and trimetallic complexes that have d^(8)–d^(8) interactions

    Testing the general validity of the Heckscher-Ohlin Theorem: the natural experiment of Japan

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    We exploit Japan's 19th century opening up to trade to test a general formulation of the Heckscher-Ohlin theorem. This formulation is based on Ohlin's measure of factor scarcity where autarky factor prices impose a refutable prediction on the economy's factor content of trade. Our test combines factor price data in Japan's autarky period with commodity trade data and a technology matrix in Japan's early free trade period. Our technology matrix is derived from a major Japanese survey of agricultural techniques during the early Meiji period, accounts by European visitors and numerous studies by Japanese and western scholars that draw on village records, business accounts and other historical sources. Evaluating Japan's factor content of trade during 1868-1875 at the corresponding autarky factor prices, we fail to reject the Heckscher-Ohlin prediction in each sample year.

    Generic Continuity of Operations/Continuity of Government Plan for State-Level Transportation Agencies, Research Report 11-01

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    The Homeland Security Presidential Directive 20 (HSPD-20) requires all local, state, tribal and territorial government agencies, and private sector owners of critical infrastructure and key resources (CI/KR) to create a Continuity of Operations/Continuity of Government Plan (COOP/COG). There is planning and training guidance for generic transportation agency COOP/COG work, and the Transportation Research Board has offered guidance for transportation organizations. However, the special concerns of the state-level transportation agency’s (State DOT’s) plan development are not included, notably the responsibilities for the entire State Highway System and the responsibility to support specific essential functions related to the State DOT Director’s role in the Governor’s cabinet. There is also no guidance on where the COOP/COG planning and organizing fits into the National Incident Management System (NIMS) at the local or state-level department or agency. This report covers the research conducted to determine how to integrate COOP/COG into the overall NIMS approach to emergency management, including a connection between the emergency operations center (EOC) and the COOP/COG activity. The first section is a presentation of the research and its findings and analysis. The second section provides training for the EOC staff of a state-level transportation agency, using a hybrid model of FEMA’s ICS and ESF approaches, including a complete set of EOC position checklists, and other training support material. The third section provides training for the COOP/COG Branch staff of a state-level transportation agency, including a set of personnel position descriptions for the COOP/COG Branch members

    School Food Environments and Policies in U.S. Public Schools

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    Examines food environments in elementary, middle, and high schools based on seventeen factors, including foods and beverages offered, the availability of vending machines, and how they vary by grade level, location, and other school characteristics

    Relaxation dynamics of the toric code in contact with a thermal reservoir: Finite-size scaling in a low temperature regime

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    We present an analysis of the relaxation dynamics of finite-size topological qubits in contact with a thermal bath. Using a continuous-time Monte Carlo method, we explicitly compute the low-temperature nonequilibrium dynamics of the toric code on finite lattices. In contrast to the size-independent bound predicted for the toric code in the thermodynamic limit, we identify a low-temperature regime on finite lattices below a size-dependent crossover temperature with nontrivial finite-size and temperature scaling of the relaxation time. We demonstrate how this nontrivial finite-size scaling is governed by the scaling of topologically nontrivial two-dimensional classical random walks. The transition out of this low-temperature regime defines a dynamical finite-size crossover temperature that scales inversely with the log of the system size, in agreement with a crossover temperature defined from equilibrium properties. We find that both the finite-size and finite-temperature scaling are stronger in the low-temperature regime than above the crossover temperature. Since this finite-temperature scaling competes with the scaling of the robustness to unitary perturbations, this analysis may elucidate the scaling of memory lifetimes of possible physical realizations of topological qubits.Comment: 14 Pages, 13 figure

    A model balancing cooperation and competition explains our right-handed world and the dominance of left-handed athletes

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    An overwhelming majority of humans are right-handed. Numerous explanations for individual handedness have been proposed, but this population-level handedness remains puzzling. Here we use a minimal mathematical model to explain this population-level hand preference as an evolved balance between cooperative and competitive pressures in human evolutionary history. We use selection of elite athletes as a test-bed for our evolutionary model and account for the surprising distribution of handedness in many professional sports. Our model predicts strong lateralization in social species with limited combative interaction, and elucidates the rarity of compelling evidence for "pawedness" in the animal world.Comment: 5 pages of text and 3 figures in manuscript, 8 pages of text and two figures in supplementary materia
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