2,059 research outputs found

    Additions and Corrections to the Stoneflies (Plecoptera) of Iowa, U.S.A.

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    (exerpt) Until recently, Iowa’s stonefly fauna was poorly documented. Heimdal et al. (2004) published a comprehensive report on stonefly distributions within the state, reporting seven families and 43 species. Five species, Allocapnia pygmaea (Burmeister) (Capiniidae), Leuctra tenuis (Pictet) (Leuctridae), Amphinemura linda (Ricker) (Nemouridae), Nemoura trispinosa Claassen (Nemouridae), and Soyedina vallicularia (Wu) (Nemouridae), were recommended for state protection because of their limited distribution within Iowa. Four species, Amphinemura delosa (Ricker), Isogenoides doratus (Frison) (Perlodidae), I. krumholzi (Ricker), and I. varians (Walsh), had limited distributions, but were not listed because their observed habitat preferences appeared common or were difficult to sample and poorly collected. From 2004 to 2006, fifteen county, state, and federal parks and preserves in east and northeast Iowa were sampled during the spring and summer in an effort to find additional locations for these nine species. The surveys yielded new distributional data for five species, including two new state records, and one species deletion, updating the total number of species recorded from Iowa to 44. A discussion for these records and corrections is presented below. Material collected from these surveys was deposited in the University of Iowa Hygienic Laboratory Collection (UHL) and the Illinois Natural History Survey Insect Collection (INHS)

    Superspace Gauge Fixing of Topological Yang-Mills Theories

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    We revisit the construction of topological Yang-Mills theories of the Witten type with arbitrary space-time dimension and number of ``shift supersymmetry'' generators, using a superspace formalism. The super-BF structure of these theories is exploited in orderto determine their actions uniquely, up to the ambiguities due to the fixing of the Yang-Mills and BF gauge invariance. UV finiteness to all orders of perturbation theory is proved in a gauge of the Landau type.Comment: 26 pages, no figures, Late

    Observables in Topological Yang-Mills Theories With Extended Shift Supersymmetry

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    We present a complete classification, at the classical level, of the observables of topological Yang-Mills theories with an extended shift supersymmetry of N generators, in any space-time dimension. The observables are defined as the Yang-Mills BRST cohomology classes of shift supersymmetry invariants. These cohomology classes turn out to be solutions of an N-extension of Witten's equivariant cohomology. This work generalizes results known in the case of shift supersymmetry with a single generator.Comment: 27 pages, Late

    Security Interest in Aircraft

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    Comment on 4D Lorentz invariance violations in the brane-world

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    The brane-world scenario offers the possibility for signals to travel outside our visible universe and reenter it. We find the condition for a signal emitted from the brane to return to the brane. We study the propagation of such signals and show that, as seen by a 4D observer, these signals arrive earlier than light traveling along the brane. We also study the horizon problem and find that, while the bulk signals can travel far enough to homogenize the visible universe, it is unlikely that they have a significant effect since they are redshifted in the gravitational field of the bulk black hole.Comment: 21 pages, 6 figures, REVTEX, New section adde

    Synthesis of multiple-input change asynchronous finite state machines

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    Asynchronous finite state machines (AFSMS) have been limited because multiple-input changes have been disallowed. In this paper, we present an architecture and synthesis system to overcome this limitation. The AFSM marks potentially hazardous state transitions, and prevents output during them. A synthesis tool to create the AFS M incorporates novel algorithms to detect the hazardous states

    Effect Of Lipid Solvents On Protein, Dna, And Collagen Synthesis In Human Skin: An Electron Microscopic Autoradiographic Study

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    The effect of acetone and kerosene on the synthesis of protein, DNA, and collagen was studied by electron microscopic autoradiography using [3H]leucine, [3H]thymidine, and [3H]proline as tracers in human skin. Quantitative analyses following concomitant administration of tritiated leucine and acetone or kerosene demonstrated, at 90 min, a marked decrease in silver grains as compared to control or nonexposed areas. Incorporation of tritiated thymidine is moderately stimulated only by acetone, whereas radioactive proline distribution is not significantly affected. Electron microscopic autoradiograms revealed that tritiated leucine is distributed over all epidermal cells, mostly in the stratum spinosum of control epidermis; a marked decrease of silver grains from [3H]leucine followed both lipid solvent exposures. The autoradiographic reaction is specifically located over cytoplasmic organelles, such as polysomes, endoplasmic reticulum, and especially tonofilaments. Tritiated thymidine resulted in silver grains mostly over nuclear chromatin and these were moderately increased after acetone application, whereas the incorporation of radioactive proline in the fibroblasts and collagen fibrils were not significantly influenced. These investigations indicate a dissociated effect of lipid solvents on protein, DNA, and collagen synthesis in human skin

    A Comprehensive Trainable Error Model for Sung Music Queries

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    We propose a model for errors in sung queries, a variant of the hidden Markov model (HMM). This is a solution to the problem of identifying the degree of similarity between a (typically error-laden) sung query and a potential target in a database of musical works, an important problem in the field of music information retrieval. Similarity metrics are a critical component of query-by-humming (QBH) applications which search audio and multimedia databases for strong matches to oral queries. Our model comprehensively expresses the types of error or variation between target and query: cumulative and non-cumulative local errors, transposition, tempo and tempo changes, insertions, deletions and modulation. The model is not only expressive, but automatically trainable, or able to learn and generalize from query examples. We present results of simulations, designed to assess the discriminatory potential of the model, and tests with real sung queries, to demonstrate relevance to real-world applications

    Gauge symmetry breaking on orbifolds

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    We discuss a new method for gauge symmetry breaking in theories with one extra dimension compactified on the orbifold S^1/Z_2. If we assume that fields and their derivatives can jump at the orbifold fixed points, we can implement a generalized Scherk-Schwarz mechanism that breaks the gauge symmetry. We show that our model with discontinuous fields is equivalent to another with continuous but non periodic fields; in our scheme localized lagrangian terms for bulk fields appear.Comment: 6 pages, 2 figures. Talk given at the XXXVIIth Rencontres de Moriond, "Electroweak interactions and unified theories", Les Arcs, France, 9-16 Mar 2002. Minor changes, one reference adde
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