7,933 research outputs found

    Multi-mesh gear dynamics program evaluation and enhancements

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    A multiple mesh gear dynamics computer program was continually developed and modified during the last four years. The program can handle epicyclic gear systems as well as single mesh systems with internal, buttress, or helical tooth forms. The following modifications were added under the current funding: variable contact friction, planet cage and ring gear rim flexibility options, user friendly options, dynamic side bands, a speed survey option and the combining of the single and multiple mesh options into one general program. The modified program was evaluated by comparing calculated values to published test data and to test data taken on a Hamilton Standard turboprop reduction gear-box. In general, the correlation between the test data and the analytical data is good

    Polaron effective mass from Monte Carlo simulations

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    A new Monte Carlo algorithm for calculating polaron effective mass is proposed. It is based on the path-integral representation of a partial partition function with fixed total quasi-momentum. Phonon degrees of freedom are integrated out analytically resulting in a single-electron system with retarded self-interaction and open boundary conditions in imaginary time. The effective mass is inversely proportional to the covariance of total energy calculated on an electron trajectory and the square distance between ends of the trajectory. The method has no limitations on values of model parameters and on the size and dimensionality of the system although large statistics is required for stable numerical results. The method is tested on the one-dimensional Holstein model for which simulation results are presented.Comment: 4 pages + 1 figure, RevTeX. Accepted for publication as a Rapid Communication in Phys.Rev.

    Doing evolution in economic geography

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    Evolutionary approaches in economic geography face questions about the relationships between their concepts, theories, methods, politics, and policy implications. Amidst the growing but unsettled consensus that evolutionary approaches should employ plural methodologies, the aims here are, first, to identify some of the difficult issues confronting those working with different frameworks. The concerns comprise specifying and connecting research objects, subjects, and levels; handling agency and context; engaging and integrating the quantitative and the qualitative; comparing cases; and, considering politics, policy, and praxis. Second, the purpose is to articulate a distinctive geographical political economy approach, methods, and illustrative examples in addressing these issues. Bringing different views of evolution in economic geography into dialogue and disagreement renders methodological pluralism a means toward improved understanding and explanation rather than an end in itself. Confronting such thorny matters needs to be embedded in our research practices and supported by greater openness; more and better substantiation of our conceptual, theoretical, and empirical claims; enhanced critical reflection; and deeper engagement with politics, policy, and praxis

    On the Localization of One-Photon States

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    Single photon states with arbitrarily fast asymptotic power-law fall-off of energy density and photodetection rate are explicitly constructed. This goes beyond the recently discovered tenth power-law of the Hellwarth-Nouchi photon which itself superseded the long-standing seventh power-law of the Amrein photon.Comment: 7 pages, tex, no figure

    Feasibility of Implementing Community Partnerships to Provide Diabetes Prevention Services to Youth

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    Type 2 diabetes (T2D) in youth has increased as a result of the obesity epidemic. Diabetes prevention programming is needed for youth, at risk for T2D, and their families. However, there is a lack of diabetes prevention services for this population. There is evidence for the benefit of lifestyle modification for decreasing diabetes risk, however there are barriers for youth to access these services in a traditional clinical setting. Our Youth Diabetes Prevention Clinic (YDPC) created partnerships within the community to increase access to diabetes prevention services for at risk youth. YDPC personnel approached community organizations who had the expertise and capacity to partner in needed areas. These partnerships allowed for the development and facilitation of a community-based diabetes prevention group. Youth and their families participated in a 12 week diabetes prevention group. We measured attendance and participant satisfaction with the program. Families attended an average of 5.1 sessions from January to October 2016. Participant satisfaction was collected five times. Physical activity was rated as “awesome” or “good” by 88% of the respondents. The nutrition activities were rated as “awesome” or “good” by 97% of respondents. Physicians and families express a desire for diabetes prevention services, however barriers make it difficult for families to fully participate. Creating partnerships within the community allows for increased access to diabetes prevention services for high-risk, underserved families

    Classical Rules in Quantum Games

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    We consider two aspects of quantum game theory: the extent to which the quantum solution solves the original classical game, and to what extent the new solution can be obtained in a classical model.Comment: The previous title, "Quantum games are no fun (yet)", was too whimsical for Physical Review. This is a comment on most, but not all, papers on quantum game theor

    Tunneling and Non-Universality in Continuum Percolation Systems

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    The values obtained experimentally for the conductivity critical exponent in numerous percolation systems, in which the interparticle conduction is by tunnelling, were found to be in the range of t0t_0 and about t0+10t_0+10, where t0t_0 is the universal conductivity exponent. These latter values are however considerably smaller than those predicted by the available ``one dimensional"-like theory of tunneling-percolation. In this letter we show that this long-standing discrepancy can be resolved by considering the more realistic "three dimensional" model and the limited proximity to the percolation threshold in all the many available experimental studiesComment: 4 pages, 2 figure

    Blood Sugar, Your Pancreas, and Unicorns: The Development of Health Education Materials for Youth With Prediabetes

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    Background. The obesity epidemic has led to an increase in prediabetes in youth, causing a serious public health concern. Education on diabetes risk and initiation of lifestyle change are the primary treatment modalities. There are few existing age-appropriate health education tools to address diabetes prevention for high-risk youth. Aim. To develop an age-appropriate health education tool(s) to help youth better understand type 2 diabetes risk factors and the reversibility of risk. Method. Health education tool development took place in five phases: exploration, design, analysis, refinement, and process evaluation. Results. The project resulted in (1) booklet designed to increase knowledge of risk, (2) meme generator that mirrors the booklet graphics and allows youth to create their own meme based on their pancreas’ current mood, (3) environmental posters for clinic, and (4) brief self-assessment that acts as a conversation starter for the health educators. Conclusion. Patients reported high likability and satisfaction with the health education tools, with the majority of patients giving the materials an “A” rating. The process evaluation indicated a high level of fidelity and related measures regarding how the health education tools were intended to be used and how they were actually used in the clinic setting
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