883 research outputs found

    Are the average gait speeds during the 10 meter and 6 minute walk tests redundant in Parkinson disease?

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    Published in final edited form as: Gait Posture. 2017 February ; 52: 178–182. doi:10.1016/j.gaitpost.2016.11.033.We investigated the relationships between average gait speed collected with the 10Meter Walk Test (Comfortable and Fast) and 6Minute Walk Test (6MWT) in 346 people with Parkinson disease (PD) and how the relationships change with increasing disease severity. Pearson correlation and linear regression analyses determined relationships between 10Meter Walk Test and 6MWT gait speed values for the entire sample and for sub-samples stratified by Hoehn & Yahr (H&Y) stage I (n=53), II (n=141), III (n=135) and IV (n=17). We hypothesized that redundant tests would be highly and significantly correlated (i.e. r>0.70, p<0.05) and would have a linear regression model slope of 1 and intercept of 0. For the entire sample, 6MWT gait speed was significantly (p<0.001) related to the Comfortable 10 Meter Walk Test (r=0.75) and Fast 10Meter Walk Test (r=0.79) gait speed, with 56% and 62% of the variance in 6MWT gait speed explained, respectively. The regression model of 6MWT gait speed predicted by Comfortable 10 Meter Walk gait speed produced slope and intercept values near 1 and 0, respectively, especially for participants in H&Y stages II-IV. In contrast, slope and intercept values were further from 1 and 0, respectively, for the Fast 10Meter Walk Test. Comfortable 10 Meter Walk Test and 6MWT gait speeds appeared to be redundant in people with moderate to severe PD, suggesting the Comfortable 10 Meter Walk Test can be used to estimate 6MWT distance in this population.This study was funded by the Davis Phinney Foundation, the Parkinson's Disease Foundation, and the National Institutes of Health (R01 NS077959, K12 HD055931, UL1 TR000448). The funding sources had no input related to study design, data collection, or decision to submit for publication. (Davis Phinney Foundation; Parkinson's Disease Foundation; R01 NS077959 - National Institutes of Health; K12 HD055931 - National Institutes of Health; UL1 TR000448 - National Institutes of Health

    Configuration development study of the X-24C hypersonic research airplane

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    Bottom line results were made of a three-phase study to determine the feasibility of designing, building, and operating, and maintaining an air-launched high performance aircraft capable of cruising at speeds up to Mach 8 for short durations. The results show that Lockalloy heat-sink structure affords the capability for a 'work-horse' vehicle which can serve as an excellent platform for this research. It was further concluded that the performance of a blended wing body configuration surpassed that of a lifting body design for typical X-24C missions. The cost of a two vehicle program, less engines, B-52 modification and contractor support after delivery, can be kept within $70M (in Jan. 1976 dollars)

    Bodybuilders\u27 Knowledge and Perceptions of the Use of Anabolic Steroids

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    This study addressed the following questions: 1. What knowledge do bodybuilders have regarding the positive and negative effects of anabolic steroids? 2. What is the perception of bodybuilders regarding the positive and negative effects of anabolic steroids

    How Supervisors Influence Performance: A Multilevel Study of Coaching and Group Management in Technology-Mediated Services

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    This multilevel study examines the role of supervisors in improving employee performance through the use of coaching and group management practices. It examines the individual and synergistic effects of these management practices. The research subjects are call center agents in highly standardized jobs, and the organizational context is one in which calls, or task assignments, are randomly distributed via automated technology, providing a quasi-experimental approach in a real-world context. Results show that the amount of coaching that an employee received each month predicted objective performance improvements over time. Moreover, workers exhibited higher performance where their supervisor emphasized group assignments and group incentives and where technology was more automated. Finally, the positive relationship between coaching and performance was stronger where supervisors made greater use of group incentives, where technology was less automated, and where technological changes were less frequent. Implications and potential limitations of the present study are discussed

    Interoperability for Autonomy

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    Autonomous systems aim to augment human capabilities with machine-based decision-making in the absence of a user. Ideally, autonomy hardware and software would be modular, having the ability to swap components in and out as needed based on necessary capabilities. However, many legacy systems in use utilize proprietary software with specific standards and components, reducing the system’s ability to be interoperable. Currently, the literature’s definition of interoperability is vague and often mistaken for other similar terms. We distinguish the uniqueness of interoperability and codify it through a taxonomy. Next, we extend this framework to understand autonomy and its hardware/software components through a proposed unified autonomy stack. We then evaluate the similarity between four autonomy architectures based on 29 stack components that are later presented in the “interchangeability matrix.” Thus, we demonstrate the necessity to unify autonomy hardware/software under the proposed taxonomy in the development of future autonomous systems

    Workplace Contextual Supports for LGBT Employees: A Review, Meta‐Analysis, and Agenda for future Research

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    The past decade has witnessed a rise in the visibility of the lesbian, gay, bisexual, and transgender (LGBT) community. This has resulted in some organizational researchers focusing their attention on workplace issues facing LGBT employees. While empirical research has been appropriately focused on examining the impact of workplace factors on the work lives of LGBT individuals, no research has examined these empirical relationships cumulatively. The purpose of this study was to conduct a comprehensive review and meta‐analysis of the outcomes associated with three workplace contextual supports (formal LGBT policies and practices, LGBT‐supportive climate, and supportive workplace relationships) and to compare the relative influence of these workplace supports on outcomes. Outcomes were grouped into four categories: (a) work attitudes, (b) psychological strain, (c) disclosure, and (d) perceived discrimination. Results show that supportive workplace relationships were more strongly related to work attitudes and strain, whereas LGBT supportive climate was more strongly related to disclosure and perceived discrimination compared to the other supports. Our findings also revealed a number of insights concerning the measurement, research design, and sample characteristics of the studies in the present review. Based on these results, we offer an agenda for future research

    The determinants of election to the United Nations Security Council

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s11127-013-0096-4.The United Nations Security Council (UNSC) is the foremost international body responsible for the maintenance of international peace and security. Members vote on issues of global importance and consequently receive perks—election to the UNSC predicts, for instance, World Bank and IMF loans. But who gets elected to the UNSC? Addressing this question empirically is not straightforward as it requires a model that allows for discrete choices at the regional and international levels; the former nominates candidates while the latter ratifies them. Using an original multiple discrete choice model to analyze a dataset of 180 elections from 1970 to 2005, we find that UNSC election appears to derive from a compromise between the demands of populous countries to win election more frequently and a norm of giving each country its turn. We also find evidence that richer countries from the developing world win election more often, while involvement in warfare lowers election probability. By contrast, development aid does not predict election

    Global population divergence and admixture of the brown rat (Rattus norvegicus)

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    Native to China and Mongolia, the brown rat (Rattus norvegicus) now enjoys a worldwide distribution. While black rats and the house mouse tracked the regional development of human agricultural settlements, brown rats did not appear in Europe until the 1500s, suggesting their range expansion was a response to relatively recent increases in global trade. We inferred the global phylogeography of brown rats using 32 k SNPs, and detected 13 evolutionary clusters within five expansion routes. One cluster arose following a southward expansion into Southeast Asia. Three additional clusters arose from two independent eastward expansions: one expansion from Russia to the Aleutian Archipelago, and a second to western North America. Westward expansion resulted in the colonization of Europe from which subsequent rapid colonization of Africa, the Americas and Australasia occurred, and multiple evolutionary clusters were detected. An astonishing degree of fine-grained clustering between and within sampling sites underscored the extent to which urban heterogeneity shaped genetic structure of commensal rodents. Surprisingly, few individuals were recent migrants, suggesting that recruitment into established populations is limited. Understanding the global population structure of R. norvegicus offers novel perspectives on the forces driving the spread of zoonotic disease, and aids in development of rat eradication programmes

    Terrestrial heat flow in North Central United States.

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1970.Vita.Bibliography: leaves 209-220.Ph.D
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