83,036 research outputs found

    Topographic Development History of the Alaska Range

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    The overall goal of this project is to use variations in sediment source through time as a proxy for deciphering the uplift history of the Alaska Range (Fig. 1). In particular, we tracked variations in sediment provenance through time for the Oligocene to present Tanana Basin. The three main sediment source regions are north of the Alaska Range, south of the Alaska Range, and from the Alaska Range itself (Fig. 2). Furthermore, we will use the sediment source interpretation to test the hypothesis that the Nenana River changed direction during the Miocene (23 Ma to 5.3 Ma) (e.g. Brennan, 2012

    What Inspires Leisure Time Invention?

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    This paper seeks to understand the intriguing but only sparsely explored phenomenon of “leisure time invention,” where the main underlying idea for the new product or process occurs when the inventor is away from the workplace. We add to previous research by focussing on the inventive creativity of the individual researcher, and reassessing the image of researchers inventing during unpaid time – who have often been dispatched as “hobbyists”. Based on the responses from a survey of over 3,000 German inventors, we tested hypotheses on the conditions under which leisure time invention is likely to arise. Results suggest that the incidence of leisure time invention is positively related to exposure to a variety of knowledge inputs – but, surprisingly, not to the quality of prior inventive output. Leisure time inventions are more frequently observed in conceptual-based technologies than in science-based technologies, in smaller R&D projects, and in externally financed R&D projects

    On asymptotic dimension of groups

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    We prove a version of the countable union theorem for asymptotic dimension and we apply it to groups acting on asymptotically finite dimensional metric spaces. As a consequence we obtain the following finite dimensionality theorems. A) An amalgamated product of asymptotically finite dimensional groups has finite asymptotic dimension: asdim A *_C B < infinity. B) Suppose that G' is an HNN extension of a group G with asdim G < infinity. Then asdim G'< infinity. C) Suppose that \Gamma is Davis' group constructed from a group \pi with asdim\pi < infinity. Then asdim\Gamma < infinity.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol1/agt-1-4.abs.htm

    Television observations of artificial aurora and analyses of flight data from NASA payload 12.18 NE

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    An accelerator nominally capable of ejecting pulses of electrons up to 6 sec in length, current to 500 ma and energy to 20 keV was flown on a rocket at 1500 October 15, 1972. The Strypi rocket was launched from the Pacific Missile Range Facility at Kauai, Hawaii. The intent was to eject electron pulses of various characteristics upwards along the magnetic field so as to produce artificial auroras in the conjugate (Southern Hemisphere) atmosphere and possibly to produce weaker auroras in the nearby atmosphere as a consequence of backscattered electrons. The accelerator package included a gas jet actuated attitude control system controlled by gyros. Attitude sensing also was accomplished by a two-axis fluxgate magnetometer, and a large foil was deployed to collect ambient electrons to neutralize the accelerator when it ejected high-energy electrons. Scientific instrumentation contained on the flight package included retarding potential analyzers, energetic electron detectors, and detectors to sense very low frequency radio noise. Image orthicon television systems and other optical sensors were operated in the conjugate region aboard two NC-135 jet aircrafts based in Samoa. Similar devices were operated at Haleakala, Hawaii, to attempt detection of auroras caused by backscattered electrons

    What Inspires Leisure Time Invention?

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    This paper seeks to understand the intriguing but only sparsely explored phenomenon of “leisure time invention,” where the main underlying idea for the new product or process occurs when the inventor is away from the workplace. We add to previous research by focussing on the inventive creativity of the individual researcher, and reassessing the image of researchers inventing during unpaid time – who have often been dispatched as “hobbyists”. Based on the responses from a survey of over 3,000 German inventors, we tested hypotheses on the conditions under which leisure time invention is likely to arise. Results suggest that the incidence of leisure time invention is positively related to exposure to a variety of knowledge inputs – but, surprisingly, not to the quality of prior inventive output. Leisure time inventions are more frequently observed in conceptual-based technologies than in science-based technologies, in smaller R&D projects, and in externally financed R&D projects.Leisure Time; Inventiveness; Organizational Creativity

    Rocket investigations of the auroral electrojet

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    Five Nike-Tomahawk rockets were flown to measure perturbations in the magnitude of the geomagnetic field due to auroral electrojets. The dates and locations of the rocket launches are given along with a brief explanation of payloads and instrumentation. Papers published as a result of the project are listed. An abstract is included which outlines the scientific results from one of the flights

    Fuzzy rule-based system applied to risk estimation of cardiovascular patients

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    Cardiovascular decision support is one area of increasing research interest. On-going collaborations between clinicians and computer scientists are looking at the application of knowledge discovery in databases to the area of patient diagnosis, based on clinical records. A fuzzy rule-based system for risk estimation of cardiovascular patients is proposed. It uses a group of fuzzy rules as a knowledge representation about data pertaining to cardiovascular patients. Several algorithms for the discovery of an easily readable and understandable group of fuzzy rules are formalized and analysed. The accuracy of risk estimation and the interpretability of fuzzy rules are discussed. Our study shows, in comparison to other algorithms used in knowledge discovery, that classifcation with a group of fuzzy rules is a useful technique for risk estimation of cardiovascular patients. © 2013 Old City Publishing, Inc
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