16,018 research outputs found

    Knots with infinitely many incompressible Seifert surfaces

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    We show that a knot in S3S^3 with an infinite number of distinct incompressible Seifert surfaces contains a closed incompressible surface in its complement.Comment: 16 pages, 6 figure

    Performance Management in Portfolio School Districts

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    Explores the challenges of performance-based oversight of portfolio districts -- districts trying to provide diverse types of schools with common standards and accountability -- and the capacities needed. Includes profiles and best practices

    US Forest Service and National Park Service Wilderness Aircraft Overflight Study: Sociological background and study plans

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    The background and sociological aspects of the combined U.S. Forest Service and National Park Service Wilderness Aircraft Overflight Study (WACOS) are presented. The WACOS broaches a new area of research by combining aspects of outdoor recreation sociology and aircraft noise response studies. The tasks faced create new challenges and require innovative solutions. Background information on the WACOS is presented with special emphasis on sociological considerations. At the time of this writing, no data have yet been collected, so this paper will present background information, related issues, and plans for data collection. Some recent studies indicate that managers of Forest Service wildernesses and National Park Service areas consider aircraft overflights to be a problem to their users in some areas. Additional relevant background research from outdoor recreation sociology is discussed, followed by presentation of the authors' opinions of the most salient sociological issues faced by this study. The goals and desired end products are identified next, followed by a review of the methods anticipated to be used to obtain these results. Finally, a discussion and conclusion section is provided

    Preliminary thoughts on an acoustic metric for the wilderness aircraft overflight study

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    Preliminary thoughts on acoustic metrics are presented which may be appropriate for the measurement of sound caused by aircraft overflights of wilderness areas. The use of parameter d'(measure of an energy flattened signal plus noise to nose relationship in the third octave, corrected for the efficiency of the observer) as a standard is considered
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