834 research outputs found

    Comparing Data Quality and Cost from Three Modes of On-Board Transit Passenger Surveys

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    This report presents the findings from a research project investigating the relative data quality and administration costs for three different modes of surveying bus passengers that produce results generalizable to the full passenger population. The three modes, all of which used survey methods distributed or administered onboard the transit vehicle, were: self-complete paper surveys, self-complete online surveys, and interviewer-assisted tablet-based surveys. Results from this study indicate several implications for practitioners choosing a survey mode. First, and most importantly, the analysis reinforces the point that there is no single, best survey mode. The choice of mode must depend on an agency’s priorities for what questions most need to be answered, what population groups are most important to represent, and exactly how the agency chooses to define concepts like a “complete” survey or a “usable” address. Findings suggest several general recommendations for current survey practice: (1) online surveys administered via an invitation distributed on the transit vehicle are not a good option; (2) old-fashioned, low-tech paper survey may still be the best option for many bus passenger surveys; (3) changes in survey results that accompany changes in survey methods should be interpreted with caution; and (4) using a new survey method, especially one relying on more complex technologies, may create unexpected glitches

    Selecting wilderness areas to conserve Utah's biological diversity

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    Journal ArticleCongress is currently evaluating the wilderness status of Bureau of Land Management (BLM) public lands in Utah. Wilderness areas play many important roles, and one critical role is the conservation of biological diversity

    Neutral-current neutrino cross section and expected supernova signals for 40^{40}Ar from a three-fold increase in the magnetic dipole strength

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    In view of the great interest in liquid argon neutrino detectors, the 40^{40}Ar(γ,γ\gamma,\gamma')40^{40}Ar^{*} reaction was revisited to guide a calculation of the neutral current neutrino cross section at supernova energies. Using the nuclear resonance fluorescence technique with a monoenergetic, 99% linearly polarized photon beam, we report a three-fold increase in magnetic dipole strength at around 10 MeV in 40^{40}Ar. Based on shell-model calculations, and using the experimentally identified transitions, the neutral current neutrino cross sections for low-energy reactions on 40^{40}Ar are calculated

    A Finite Element Computation of the Gravitational Radiation emitted by a Point-like object orbiting a Non-rotating Black Hole

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    The description of extreme-mass-ratio binary systems in the inspiral phase is a challenging problem in gravitational wave physics with significant relevance for the space interferometer LISA. The main difficulty lies in the evaluation of the effects of the small body's gravitational field on itself. To that end, an accurate computation of the perturbations produced by the small body with respect the background geometry of the large object, a massive black hole, is required. In this paper we present a new computational approach based on Finite Element Methods to solve the master equations describing perturbations of non-rotating black holes due to an orbiting point-like object. The numerical computations are carried out in the time domain by using evolution algorithms for wave-type equations. We show the accuracy of the method by comparing our calculations with previous results in the literature. Finally, we discuss the relevance of this method for achieving accurate descriptions of extreme-mass-ratio binaries.Comment: RevTeX 4. 18 pages, 8 figure

    Magnetic Resonance

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    Contains research objectives and reports on three research projects

    Fecal Microbiota Transplantation in Parkinson’s Disease-A Randomized Repeat-Dose, Placebo-Controlled Clinical Pilot Study

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    BACKGROUND AND PURPOSE: The intestinal microbiome plays a primary role in the pathogenesis of neurodegenerative disorders and may provide an opportunity for disease modification. We performed a pilot clinical study looking at the safety of fecal microbiota transplantation (FMT), its effect on the microbiome, and improvement of symptoms in Parkinson\u27s disease. METHODS: This was a randomized, double-blind placebo-controlled pilot study, wherein orally administered lyophilized FMT product or matching placebo was given to 12 subjects with mild to moderate Parkinson\u27s disease with constipation twice weekly for 12 weeks. Subjects were followed for safety and clinical improvement for 9 additional months (total study duration 12 months). RESULTS: Fecal microbiota transplantation caused non-severe transient upper gastrointestinal symptoms. One subject receiving FMT was diagnosed with unrelated metastatic cancer and was removed from the trial. Beta diversity (taxa) of the microbiome, was similar comparing placebo and FMT groups at baseline, however, for subjects randomized to FMT, it increased significantly at 6 weeks ( CONCLUSIONS: Subjects with Parkinson\u27s disease tolerated multi-dose-FMT, and experienced increased diversity of the intestinal microbiome that was associated with reduction in constipation and improved gut transit and intestinal motility. Fecal microbiota transplantation administration improved subjective motor and non-motor symptoms. CLINICAL TRIAL REGISTRATION: ClinicalTrial.gov, identifier: NCT03671785

    Feedback in laparoscopic skills acquisition: an observational study during a basic skills training course

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    This study aimed to obtain insight in the effect of expert feedback during a basic laparoscopic skills training course for residents. A questionnaire was held among participants regarding provided feedback and the self-perceived laparoscopic skills improvement. The participants (n = 24) who completed the questionnaire were in their first to fifth postgraduate year. Most feedback was directed at intracorporeal knot tying (47% reported extensive feedback), while camera navigation and body positioning received the least feedback (40% and 43%, respectively, responded to have received no feedback at all). After the course, the self-perceived competence in intracorporeal knot tying and cutting had improved significantly, while camera navigation, body positioning, pointing, and grasping tasks did not improve. In conclusion, most benefit from expert feedback can be obtained at the start of the learning curve. Therefore, the basic laparoscopic skills course should be attended early in residency. Additionally, it is crucial that training objectives are clear prior to a course for both the expert and the trainee, in order to focus the feedback on all training objectives
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