13,564 research outputs found

    Galactic extinction and Abell clusters

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    In this paper, we present the results of comparing the angular distribution of Abell clusters with Galactic HI measurements. For most subsamples of clusters considered, their positions on the sky appear to be anti-correlated with respect to the distribution of HI column densities. The statistical significance of these observed anti-correlations is a function of both richness and distance class, with the more distant and/or richest systems having the highest significance (~3 sigma). The lower richness, nearby clusters appear to be randomly distributed compared to the observed Galactic HI column density.Comment: 5 pages, uuencoded compressed postscript file. Figures included. Accepted by MNRA

    A Comparison of Continuously Controlled and Controlled K-theory

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    We define an unreduced version of the e-controlled lower KK-theoretic groups of Ranicki and Yamasaki, and Quinn. We show that the reduced versions of our groups coincide (in the inverse limit and its first derived, lim⁥1\lim^1) with those of Ranicki and Yamasaki. We also relate the controlled groups to the continuously controlled groups of Anderson and Munkholm, and to the Quinn homology groups of Quinn

    Beam profile measurements on RHIC

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    Laser Beam-Profile Monitor Development at BNL for SNS

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    Protecting Menard’s Quixote: A Return to the Strict Originality Standard in Copyright Law

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    Copyright protection extends to “original” works. The adjective “original” here means a work that originated with its purported author, and is not meant to impute any novelty requirement to copyright law. However, case law and literature offer up several odd examples where two individuals have independently created identical works of art. The theory underlying copyright law requires that, because each work originated independently from separate authors, each work be independently copyrightable. Applying this strict, objective standard of originality to the transformative arts, we begin to see new possibilities for grounding copyrights in parodies and satires. Under current law, parodies escape infringement of their target works through the “fair use” exception to copyright law, while satires frequently do not. However, this essay argues that, under a strict interpretation of the originality standard, parodies and satires alike can be considered independently created works of art that are not derivative of (and hence not infringing) their target works. This essay suggests the application of a new standard of ascertainably different meanings when determining whether one work infringes upon a similar work

    Are the Earth and the Moon compositionally alike? Inferences on lunar composition and implications for lunar origin and evolution from geophysical modeling

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    The main objective of the present study is to discuss in detail the results obtained from an inversion of the Apollo lunar seismic data set, lunar mass, and moment of inertia. We inverted directly for lunar chemical composition and temperature using the model system CaO-FeO-MgO-Al2O3-SiO2. Using Gibbs free energy minimization, stable mineral phases at the temperatures and pressures of interest, their modes and physical properties are calculated. We determine the compositional range of the oxide elements, thermal state, Mg#, mineralogy and physical structure of the lunar interior, as well as constraining core size and density. The results indicate a lunar mantle mineralogy that is dominated by olivine and orthopyroxene ( 80 vol%), with the remainder being composed of clinopyroxene and an aluminous phase (plagioclase, spinel, and garnet present in the depth ranges 0–150 km, 150–200 km, and >200 km, respectively). This model is broadly consistent with constraints on mantle mineralogy derived from the experimental and observational study of the phase lationships and trace element compositions of lunar mare basalts and picritic glasses. In particular, by melting a typical model mantle composition using the pMELTS algorithm, we found that a range of batch melts generated from these models have features in common with low Ti mare basalts and picritic glasses. Our results also indicate a bulk lunar composition and Mg# different to that of the Earth’s upper mantle, represented by the pyrolite composition. This difference is reflected in a lower bulk lunar Mg# ( 0.83). Results also indicate a small iron-like core with a radius around 340 km.The Carlsberg Foundation, NER

    Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

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    A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required
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