1,316 research outputs found

    A flexible flight display research system using a ground-based interactive graphics terminal

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    Requirements and research areas for the air transportation system of the 1980 to 1990's were reviewed briefly to establish the need for a flexible flight display generation research tool. Specific display capabilities required by aeronautical researchers are listed and a conceptual system for providing these capabilities is described. The conceptual system uses a ground-based interactive graphics terminal driven by real-time radar and telemetry data to generate dynamic, experimental flight displays. These displays are scan converted to television format, processed, and transmitted to the cockpits of evaluation aircraft. The attendant advantages of a Flight Display Research System (FDRS) designed to employ this concept are presented. The detailed implementation of an FDRS is described. The basic characteristics of the interactive graphics terminal and supporting display electronic subsystems are presented and the resulting system capability is summarized. Finally, the system status and utilization are reviewed

    Exercise intervention in brain injury: a pilot randomized study of Tai Chi Qigong

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    Objective: To examine the effects of a brief Tai Chi Chuan Qigong (‘Qigong’) exercise intervention on individuals with traumatic brain injury. Design: A single-centre randomized controlled trial pilot study. Setting: A registered charity day centre in the community. Subjects: Twenty individuals with traumatic brain injury. Intervention: Intervention participants attended a Qigong exercise session for one hour per week over eight weeks. Control participants engaged in non-exercise-based social and leisure activities for the same intervention period. Measures: Outcome was assessed at baseline and post intervention using the General Health Questionnaire-12, the Physical Self-Description Questionnaire and the Social Support for Exercise Habits Scale, to measure perceived mood, self-esteem, flexibility, coordination, physical activity and social support. Results: Groups were comparable at baseline. After the intervention, mood was improved in the exercise group when compared with controls (U ¼ 22.0, P ¼ 0.02). Improvements in self-esteem (Z ¼ 2.397, P ¼ 0.01) and mood (Z ¼ –2.032, P ¼ 0.04) across the study period were also evident in the exercise group only. There were no significant differences in physical functioning between groups. In view of the sample size, these findings are inconclusive. Conclusions: This study provides preliminary evidence that a brief Qigong exercise intervention programme may improve mood and self-esteem for individuals with traumatic brain injury. This needs to be tested in a large-scale randomized trial

    Countermeasures to Enhance Sensorimotor Adaptability

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    During exploration-class missions, sensorimotor disturbances may lead to disruption in the ability to ambulate and perform functional tasks during the initial introduction to a novel gravitational environment following a landing on a planetary surface. The goal of our current project is to develop a sensorimotor adaptability (SA) training program to facilitate rapid adaptation to novel gravitational environments. We have developed a unique training system comprised of a treadmill placed on a motion-base facing a virtual visual scene that provides an unstable walking surface combined with incongruent visual flow designed to enhance sensorimotor adaptability. We have conducted a series of studies that have shown: Training using a combination of modified visual flow and support surface motion during treadmill walking enhances locomotor adaptability to a novel sensorimotor environment. Trained individuals become more proficient at performing multiple competing tasks while walking during adaptation to novel discordant sensorimotor conditions. Trained subjects can retain their increased level of adaptability over a six months period. SA training is effective in producing increased adaptability in a more complex over-ground ambulatory task on an obstacle course. This confirms that for a complex task like walking, treadmill training contains enough of the critical features of overground walking to be an effective training modality. The structure of individual training sessions can be optimized to promote fast/strategic motor learning. Training sessions that each contain short-duration exposures to multiple perturbation stimuli allows subjects to acquire a greater ability to rapidly reorganize appropriate response strategies when encountering a novel sensory environment. Individual sensory biases (i.e. increased visual dependency) can predict adaptive responses to novel sensory environments suggesting that customized training prescriptions can be developed to enhance adaptability. These results indicate that SA training techniques can be added to existing treadmill exercise equipment and procedures to produce a single integrated countermeasure system to improve performance of astro/cosmonauts during prolonged exploratory space missions

    Low-rate communications utilizing digital coding and modulation

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    All digital communications signal design using convolutional coding and PSK modulation for two-way transmission of voice and data between space shuttle and groun

    Coexisting Fermi Liquid and Strange Metal Phenomena in Sr2_2RuO4_4

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    The strange metal is an enigmatic phase whose properties are irreconcilable with the established Fermi liquid theory of conductors. A fundamental question is whether a strange metal and a Fermi liquid are distinct phases of matter, or whether a material can be intermediate between or in a superposition of the two. We studied the collective density response of the correlated metal Sr2_2RuO4_4 by momentum-resolved electron energy-loss spectroscopy (M-EELS). We discovered that a broad continuum of non-propagating charge fluctuations (a characteristic of strange metals) and also a dispersing Fermi liquid-like collective mode at low energies and long wavelengths coexist in the same material at the same temperature. These features exhibit a spectral weight redistribution and velocity renormalization when we cool the material through the quasiparticle coherence temperature. Our results show not only that strange metal and Fermi liquid phenomena can coexist but also that Sr2_2RuO4_4 serves as an ideal test case for studying the interaction between the two.Comment: 12 pages, 4 figure
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