5,140 research outputs found

    A generic multi-flex-body dynamics, controls simulation tool for space station

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    An order (n) multiflex body Space Station simulation tool is introduced. The flex multibody modeling is generic enough to model all phases of Space Station from build up through to Assembly Complete configuration and beyond. Multibody subsystems such as the Mobile Servicing System (MSS) undergoing a prescribed translation and rotation are also allowed. The software includes aerodynamic, gravity gradient, and magnetic field models. User defined controllers can be discrete or continuous. Extensive preprocessing of 'body by body' NASTRAN flex data is built in. A significant aspect, too, is the integrated controls design capability which includes model reduction and analytic linearization

    Peculiar Features of the Interaction Potential between Hydrogen and Antihydrogen at Intermediate Separations

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    We evaluate the interaction potential between a hydrogen and an antihydrogen using the second-order perturbation theory within the framework of the four-body system in a separable two-body basis. We find that the H-Hbar interaction potential possesses the peculiar features of a shallow local minimum located around interatomic separations of r ~ 6 a.u. and a barrier rising at r~5 a.u. Additional theoretical and experimental investigations on the nature of these peculiar features will be of great interest.Comment: 13 pages, 6 figure

    Bounds on New Physics from B -> V1 V2 Decays

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    We consider the possibility that physics beyond the standard model contributes to the decays B -> V1 V2, where V1 and V2 are vector mesons. We show that a time-dependent angular analysis of B -> V1 V2 decays provides many tests for this new physics (NP). Furthermore, although one cannot solve for the NP parameters, we show that this angular analysis allows one to put bounds on these parameters. This can be useful in estimating the scale of NP, and can tell us whether any NP found directly at future high-energy colliders can be responsible for effects seen in B -> V1 V2 decays.Comment: 23 pages, plain LaTeX, 5 figures (included

    Canonical transformations in quantum mechanics

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    This paper presents the general theory of canonical transformations of coordinates in quantum mechanics. First, the theory is developed in the formalism of phase space quantum mechanics. It is shown that by transforming a star-product, when passing to a new coordinate system, observables and states transform as in classical mechanics, i.e., by composing them with a transformation of coordinates. Then the developed formalism of coordinate transformations is transferred to a standard formulation of quantum mechanics. In addition, the developed theory is illustrated on examples of particular classes of quantum canonical transformations.Comment: 26 page

    Impact of a brief faculty training to improve patient-centered communication while using electronic health records

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    Objective Despite rapid EHR adoption, few faculty receive training in how to implement patient-centered communication skills while using computers in exam rooms. We piloted a patient-centered EHR use training to address this issue. Methods Faculty received four hours of training at Cleveland Clinic and a condensed 90-minute version at the University of Chicago. Both included a lecture and a Group-Objective Structured Clinical Exam (GOSCE) experience. Direct observations of 10 faculty in their clinical practices were performed pre- and post-workshop. Results Thirty participants (94%) completed a post-workshop evaluation assessing knowledge, attitude, and skills. Faculty reported that training was important, relevant, and should be required for all providers; no differences were found between longer versus shorter training. Participants in the longer training reported higher GOSCE efficacy, however shorter workshop participants agreed more with the statement that they had gained new knowledge. Faculty improved their patient-centered EHR use skills in clinical practice on post- versus pre-workshop ratings using a validated direct-observation rating tool. Conclusion A brief lecture and GOSCE can be effective in training busy faculty on patient-centered EHR use skills. Practice Implications Faculty training on patient-centered EHR skills can enhance patient-doctor communication and promotes positive role modeling of these skills to learners

    Adding value to laboratory medicine: a professional responsibility

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    Laboratory medicine is a medical specialty at the centre of healthcare. When used optimally laboratory medicine generates knowledge that can facilitate patient safety, improve patient outcomes, shorten patient journeys and lead to more cost-effective healthcare. Optimal use of laboratory medicine relies on dynamic and authoritative leadership outside as well as inside the laboratory. The first responsibility of the head of a clinical laboratory is to ensure the provision of a high quality service across a wide range of parameters culminating in laboratory accreditation against an international standard, such as ISO 15189. From that essential baseline the leadership of laboratory medicine at local, national and international level needs to ‘add value’ to ensure the optimal delivery, use, development and evaluation of the services provided for individuals and for groups of patients. A convenient tool to illustrate added value is use of the mnemonic ‘SCIENCE’. This tool allows added value to be considered in seven domains: standardisation and harmonisation; clinical effectiveness; innovation; evidence-based practice; novel applications; cost-effectiveness; and education of others. The assessment of added value in laboratory medicine may be considered against a framework that comprises three dimensions: operational efficiency; patient management; and patient behaviours. The profession and the patient will benefit from sharing examples of adding value to laboratory medicine

    Local processing in neurites of VGluT3- expressing amacrine cells differentially organizes visual information

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    Neurons receive synaptic inputs on extensive neurite arbors. How information is organized across arbors and how local processing in neurites contributes to circuit function is mostly unknown. Here, we used two-photon Ca2+ imaging to study visual processing in VGluT3-expressing amacrine cells (VG3-ACs) in the mouse retina. Contrast preferences (ON vs. OFF) varied across VG3-AC arbors depending on the laminar position of neurites, with ON responses preferring larger stimuli than OFF responses. Although arbors of neighboring cells overlap extensively, imaging population activity revealed continuous topographic maps of visual space in the VG3-AC plexus. All VG3-AC neurites responded strongly to object motion, but remained silent during global image motion. Thus, VG3-AC arbors limit vertical and lateral integration of contrast and location information, respectively. We propose that this local processing enables the dense VG3-AC plexus to contribute precise object motion signals to diverse targets without distorting target-specific contrast preferences and spatial receptive fields.</jats:p

    Non-Abelian, Self-Dual Chern-Simons Vortices Coupled to Gravity

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    In this article we consider SU(2)SU(2) Chern-Simons/Higgs theory coupled to gravity in three-dimensions. It is shown that for a cylindrically symmetric vortex both the Einstein equations and the field equations can be reduced to a set of first-order Bogomol'nyi equations provided that we choose a specific eighth-order potential.Comment: 21 pages, LATEX, no figure
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