3,806 research outputs found

    Why the general Zakharov-Shabat equations form a hierarchy?

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    The totality of all Zakharov-Shabat equations (ZS), i.e., zero-curvature equations with rational dependence on a spectral parameter, if properly defined, can be considered as a hierarchy. The latter means a collection of commuting vector fields in the same phase space. Further properties of the hierarchy are discussed, such as additional symmetries, an analogue to the string equation, a Grassmannian related to the ZS hierarchy, and a Grassmannian definition of soliton solutions.Comment: 13p

    Protection in the United States for “Famous Marks”: The Federal Trademark Dilution Act Revisited

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    Neutral hydrogen in the starburst galaxy NGC3690/IC694

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    Researchers made observations of the neutral hydrogen (HI) emission structure surrounding the very deep absorption peak (observed earlier by Dickey (1986)) in the galaxy pair NGC3690/IC694. This galaxy pair is highly luminous in the far infrared, and known to exhibit extensive star formation as well as nuclear activity. Knowledge of the spatial distribution and velocity structure of the HI emission is of great importance to the understanding of the dynamics of the interaction and the resulting environmental effects on the galaxies

    Down at the Hospital

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    Down at the hospital the other day the ambulance brought us an old German lady who had fallen down on Main Street. We admitted her in east wing and found no bodily damage, but did discover that she was thoroughly drunk. We removed her warmed-over cabbage tennis shoes and were in the process of replacing her Salvation Army discount dress with a hospital gown when three or four bags of Hershey\u27s chocolate kisses fell out from some hidden foyer of her person. All the while she was yelling about her husband\u27s federal pension and how her bishop and the police department would protect her from us. Last night she escaped from the hospital, and I, being the orderly on duty, had to hyperambulate down the street to capture her and return her to east wing, using force if necessary. It was. A half-hour later back in room 6, I was gratified to see 5 cc’s of dilantin enter her left buttock via hypodermic needle because I knew that she would be as happy in dreamland as I was to see her transported there

    HRTEM study of a new non-stoichiometric BaTiO(3-δ) structure

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    BaTiO3-based multilayer ceramic capacitors (MLCCs) with Ni internal electrodes are co-fired in reducing atmospheres to avoid oxidation of the electrode. Although dielectric materials are doped by acceptor, donor and amphoteric dopants to minimize the oxygen vacancy content, there is still a large concentration of oxygen vacancies that are accommodated in the BaTiO3 active layers. In general, ABO3 perovskites demonstrates a strong ability to accommodate the oxygen vacancies and maintain a regular pseudo-cubic structure. Oxygen deficient barium titanate can be transformed to a hexagonal polymorph (h-BT) at high temperatures1,2. In this paper, we report the new modulated and long range ordered structures of non-stoichiometric BaTiO3-δ that are observed in the electrically degraded Ni-BaTiO3 MLCCs at low temperature

    The Multicomponent KP Hierarchy: Differential Fay Identities and Lax Equations

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    In this article, we show that four sets of differential Fay identities of an NN-component KP hierarchy derived from the bilinear relation satisfied by the tau function of the hierarchy are sufficient to derive the auxiliary linear equations for the wave functions. From this, we derive the Lax representation for the NN-component KP hierarchy, which are equations satisfied by some pseudodifferential operators with matrix coefficients. Besides the Lax equations with respect to the time variables proposed in \cite{2}, we also obtain a set of equations relating different charge sectors, which can be considered as a generalization of the modified KP hierarchy proposed in \cite{3}.Comment: 19 page

    Identification of four RXTE Slew Survey sources with nearby luminous active galactic nuclei

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    Based on RXTE scans and observations with the SWIFT/XRT telescope and INTEGRAL observatory, we report the identification of four X-ray sources discovered during the RXTE Slew Survey of the |b|>10deg sky with nearby (z ~ 0.017-0.098) luminous (log L_2-10keV ~ 42.7-44 erg/s) active galactic nuclei. Two of the objects exhibit heavily intrinsically absorbed X-ray spectra (NHL~10^23 cm^-2).Comment: 4 pages, 2 figures. Sibmitted to Astronomy and Astrophysics Letter

    P18. Backstroke Start Performance: The Impact of Using the Omega Backstroke Ledge

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    Background: FINA recently approved use of the “backstroke ledge” (Omega OBL2) to improve backstroke start performance in competition, but its performance has not been thoroughly evaluated. The purpose of this study was to compare starts performed on a flat wall to those performed with the OBL2, and to identify factors that contribute to better start performance. Methods: Ten elite backstroke swimmers performed three flat-wall and three OBL2 starts. Horizontal impulse, vertical impulse, takeoff velocity and takeoff angle were calculated from the force plate data. Entry distance, time to 10 m and start of hip and knee extension were recorded using digital video cameras. Results: We determined that starts performed with the OBL2 had a faster time to 10 m, less variability in vertical impulse and greater entry distance. Time to 10 m and head entry distance had a significant negative correlation. Starts with the OBL2 also had a trend toward lower resultant takeoff velocity, lower horizontal impulse and greater COM takeoff angle. Discussion and Conclusions: The OBL2 appears to provide a performance advantage by allowing an increased head entry distance, rather than larger impulse on the wall. Additional studies are needed to evaluate the factors that contribute to improved performance when using the OBL2. Coaches may consider head entry distance as a training target. Athletes should use the OBL2 in training and competition to ensure optimal start performance. Interdisciplinary Reflection: Concepts from physical and biological sciences are combined to explain the factors which affect backstroke start performance
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