24,569 research outputs found

    NASA automatic subject analysis technique for extracting retrievable multi-terms (NASA TERM) system

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    Current methods for information processing and retrieval used at the NASA Scientific and Technical Information Facility are reviewed. A more cost effective computer aided indexing system is proposed which automatically generates print terms (phrases) from the natural text. Satisfactory print terms can be generated in a primarily automatic manner to produce a thesaurus (NASA TERMS) which extends all the mappings presently applied by indexers, specifies the worth of each posting term in the thesaurus, and indicates the areas of use of the thesaurus entry phrase. These print terms enable the computer to determine which of several terms in a hierarchy is desirable and to differentiate ambiguous terms. Steps in the NASA TERMS algorithm are discussed and the processing of surrogate entry phrases is demonstrated using four previously manually indexed STAR abstracts for comparison. The simulation shows phrase isolation, text phrase reduction, NASA terms selection, and RECON display

    Anomalous enhancement of a penguin hadronic matrix element in B->K eta'

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    We estimate the density matrix element for the pi^0, eta and eta' production from the vacuum in the large-N_c limit. As a consequence, we find that the QCD axial anomaly leads to highly non-trivial corrections to the usual flavour SU(3) relations between B^0-> K^0 pi^0, B^0-> K^0 eta and B^0-> K^0 eta' decay amplitudes. These corrections may explain why the B-> K eta' branching ratio is about six times larger than the B-> K pi one.Comment: 5 pages, 1 figur

    Two new neotropical Aeshnines (Odonata)

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    http://deepblue.lib.umich.edu/bitstream/2027.42/56657/1/OP218.pd

    Five new Mexican dragonflies (Odonata)

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    http://deepblue.lib.umich.edu/bitstream/2027.42/56655/1/OP216.pd

    The genus Perilestes (Odonata)

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    http://deepblue.lib.umich.edu/bitstream/2027.42/56259/1/MP014.pd

    Predictable hydrodynamic conditions explain temporal variations in the density of benthic foraging seabirds in a tidal stream environment

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    VC International Council for the Exploration of the Sea 2016. James J. Waggitt was funded by a NERC Case studentship supported by OpenHydro Ltd and Marine Scotland Science (NE/J500148/1). Shore-based surveys were funded by a NERC (NE/J004340/1) and a Scottish National Heritage (SNH) grant. FVCOM was funded by a NERC grant (NE/J004316/1). The bathymetry data used in hydrodynamic models (HI 1122 Sanday Sound to Westray Firth) was collected by the Maritime and Coastguard Agency (MCA) as part of the UK Civil Hydrography Programme. We wish to thank Christina Bristow, Matthew Finn and Jennifer Norris at the European Marine Energy Centre (EMEC); Ian Davies at Marine Scotland Science; Gail Davoren, Shaun Fraser, Pauline Goulet, Alex Robbins and Helen Wade for invaluable discussions; Thomas Cornulier, Alex Douglas, James Grecian and Samantha Patrick for their help with statistical analysis; and Jenny Campbell and the Cockram family for assistance during fieldwork.Peer reviewedPublisher PD

    Vortex interactions and decay in aircraft wakes

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    The dynamic interaction of aircraft wake vortices was investigated using both inviscid and viscous models. For the viscous model, a computer code was developed using a second-order closure model of turbulent transport. The phenomenon of vortex merging which results in the rapid aging of a vortex wake was examined in detail. It was shown that the redistribution of vorticity during merging results from both convective and diffusive mechanisms

    Meson-exchange Currents and Quasielastic Neutrino Cross Sections

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    We illustrate and discuss the role of meson-exchange currents in quasielastic neutrino-nucleus scattering induced by charged currents, comparing the results with the recent MiniBooNE data for differential and integrated cross sections.Comment: 9 pages, 8 figures; Proceedings of the 30th International Workshop on Nuclear Theory IWNT30, Rila Mountains, Bulgaria, June 27 - July 2, 201
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