16,847 research outputs found
Knots with infinitely many incompressible Seifert surfaces
We show that a knot in 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
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
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
Solutions for Neutral for Axi-Dilaton Gravity in 4-Dimensions
We examine a 1 parameter class of actions describing the gravitational
interaction between a pair of scalar fields and Einsteinian gravitation. When
the parameter is positive the theory corresponds to an axi-dilatonic sector of
low energy string theory. We exploit an SL(2,R) symmetry of the theory to
construct a family of electromagnetically neutral solutions with non-zero axion
and dilaton charge from solutions of the Brans-Dicke theory. We also comment on
solutions to the theory with negative coupling parameter.Comment: 7 pages Plain Tex (No Figures), Letter to Editor, Classical and
Quantum Gravit
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