12,667 research outputs found

    Four dimensional topological quantum field theory, Hopf categories, and the canonical bases

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    We propose a new mwthod of constructing 4D-TQFTs. The method uses a new type of algebraic structure called a Hopf Category. We also outline the construction of a family of Hopf categories related to the quantum groups, using the canonical bases.Comment: 38 page

    Fifth Presentation of the James B. Macelwane Award, April 20, 1966

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    Don Anderson was born in Frederick, Maryland, thirty-three years ago. He took his Bachelor's degree at Rennselaer Polytechnic Institute in 1955. Between 1955 and 1958 he worked for Chevron Oil Company, served in the Air Force, and conducted research for the Arctic Institute of North America. He received his Ph.D. from Caltech in 1962, where he currently serves as Associate Professor of Geophysics. Don L. Anderson has utilized the range of modern observations concerning seismic body and surface waves, the free vibrations, and the loss characteristics of all these to re-evaluate and to revise interpretations of the elastic and anelastic structure of the Earth. He has analyzed recent observations of large artificial explosions to elucidate the complex events in the epicentral range 10°–40°, where he finds that a succession of triple-valued travel-time curves appears to occur. These curves are interpreted in terms of two regions of rapid increase in both velocity and density, one at the bottom of the Gutenberg low-speed zone at depth 300 km, the other at depth 600 km. These interpretations are consistent with the results from free-mode observations. The two levels of rapid changes may represent zones of phase change. In the lower mantle, the density increases very slowly relative to the rates in the earlier Earth models

    Hydrodynamic and Brownian Fluctuations in Sedimenting Suspensions

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    We use a mesoscopic computer simulation method to study the interplay between hydrodynamic and Brownian fluctuations during steady-state sedimentation of hard sphere particles for Peclet numbers (Pe) ranging from 0.1 to 15. Even when the hydrodynamic interactions are an order of magnitude weaker than Brownian forces, they still induce backflow effects that dominate the reduction of the average sedimentation velocity with increasing particle packing fraction. Velocity fluctuations, on the other hand, begin to show nonequilibrium hydrodynamic character for Pe > 1Comment: 4 pages 4 figures, RevTex, to appear in Phys. Rev. Lett. New version with some minor correction

    CGIAR citations in IPCC reports: a summary report

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    In March 2015, Science-Metrix was contracted by CGIAR to evaluate the presence of CGIAR publications in the IPCC assessment reports (ARs). The study was carried through the analysis of the IPCC ARs' references

    Design to reliability shielded vertical interconnection applied to microwave Chip Scale Packaging

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    This paper presents the electrical design, measurement and reliability ests of a shielded vertical interconnection dedicated to microwave solder-mount packages. Electromagnetic simulations show very good results up to 20 GHz. Test samples have been designed and manufactured. Electrical results are in accordance with the simulations with insertion loss lower than 0.1 dB up to 20 GHz for the proposed interconnection. Reliability tests of present no degradation of the after 500 thermal cycles in the [-55°C, +125°C] temperature range

    Topological Designs

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    We give an exponential upper and a quadratic lower bound on the number of pairwise non-isotopic simple closed curves can be placed on a closed surface of genus g such that any two of the curves intersects at most once. Although the gap is large, both bounds are the best known for large genus. In genus one and two, we solve the problem exactly. Our methods generalize to variants in which the allowed number of pairwise intersections is odd, even, or bounded, and to surfaces with boundary components.Comment: 14 p., 4 Figures. To appear in Geometriae Dedicat

    Weakly versus highly nonlinear dynamics in 1D systems

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    We analyze the morphological transition of a one-dimensional system described by a scalar field, where a flat state looses its stability. This scalar field may for example account for the position of a crystal growth front, an order parameter, or a concentration profile. We show that two types of dynamics occur around the transition: weakly nonlinear dynamics, or highly nonlinear dynamics. The conditions under which highly nonlinear evolution equations appear are determined, and their generic form is derived. Finally, examples are discussed.Comment: to be published in Europhys. Let

    An adjudicated hermeneutic single-case efficacy design study of experiential therapy for panic/phobia

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    This paper illustrates the application of an adjudicated form of Hermeneutic Single Case Efficacy Design (HSCED), a critical-reflective method for inferring change and therapeutic influence in single therapy cases. The client was a 61 year-old European-American male diagnosed with panic and bridge phobia. He was seen for 23 sessions of individual Process-Experiential/Emotion-Focused Therapy. In this study, affirmative and skeptic teams of researchers developed opposing arguments regarding whether the client changed over therapy and whether therapy was responsible for these changes. Three judges representing different theoretical orientations then assessed data and arguments, rendering judgments in favor of the affirmative side. We discuss clinical implications and recommendations for the future interpretive case study research
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