20,615 research outputs found

    Fog dispersion

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    The concept of using the charged particle technique to disperse warm fog at airports is investigated and compared with other techniques. The charged particle technique shows potential for warm fog dispersal, but experimental verification of several significant parameters, such as particle mobility and charge density, is needed. Seeding and helicopter downwash techniques are also effective for warm fog disperals, but presently are not believed to be viable techniques for routine airport operations. Thermal systems are currently used at a few overseas airports; however, they are expensive and pose potential environmental problems

    A review of the meteorological parameters which affect aerial application

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    The ambient wind field and temperature gradient were found to be the most important parameters. Investigation results indicated that the majority of meteorological parameters affecting dispersion were interdependent and the exact mechanism by which these factors influence the particle dispersion was largely unknown. The types and approximately ranges of instrumented capabilities for a systematic study of the significant meteorological parameters influencing aerial applications were defined. Current mathematical dispersion models were also briefly reviewed. Unfortunately, a rigorous dispersion model which could be applied to aerial application was not available

    The concept of social pharmacy

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    The 13th International Social Pharmacy Workshop will be held in Malta in July 2004. The Social Pharmacy Workshops are international conferences for research in social and behavioural pharmacy. Meetings are held every second year and participation has grown steadily since the first Workshop was held in Helsinki, Finland, in 1980. Following the successful 2002 conference in Sydney, Australia, the 2004 meeting in Malta will be the first one held in the Mediterranean area!peer-reviewe

    On the positive eigenvalues and eigenvectors of a non-negative matrix

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    The paper develops the general theory for the items in the title, assuming that the matrix is countable and cofinal.Comment: Version 2 allows the matrix to have zero row(s) and rows with infinitely many non-zero entries. In addition the introduction has been rewritte

    Hawking Radiation for Non-minimally Coupled Matter from Generalized 2D Black Hole Models

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    It is well known that spherically symmetric reduction of General Relativity (SSG) leads to non-minimally coupled scalar matter. We generalize (and correct) recent results to Hawking radiation for a class of dilaton models which share with the Schwarzschild black hole non-minimal coupling of scalar fields and the basic global structure. An inherent ambiguity of such models (if they differ from SSG) is discussed. However, for SSG we obtain the rather disquieting result of a negative Hawking flux at infinity, if the usual recipe for such calculations is applied.Comment: 8 page

    ADIPLS -- the Aarhus adiabatic oscillation package

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    Development of the Aarhus adiabatic pulsation code started around 1978. Although the main features have been stable for more than a decade, development of the code is continuing, concerning numerical properties and output. The code has been provided as a generally available package and has seen substantial use at a number of installations. Further development of the package, including bringing the documentation closer to being up to date, is planned as part of the HELAS Coordination Action.Comment: Astrophys. Space Sci., in the pres

    The Application Of Neyman-Pearson Methodology To The Estimation Of Web Advertising Viewers

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    As electronic commerce continues to expand as a medium of choice in transaction markets, issues of advertising effectiveness and exposure have become increasingly salient. While the literature is replete concerning levels of exposure for more traditional forms of advertising and commerce, the extension of much of this work to the electronic commerce market is limited, despite the wealth of online tracking information that does not exist in more traditional markets.  This manuscript addresses this limitation by considering the important issue of estimating advertisement exposure for “banner” or “target” advertisements within electronic commerce through the utilization of standard Neyman-Pearson statistical methodology

    The Dimensional-Reduction Anomaly in Spherically Symmetric Spacetimes

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    In D-dimensional spacetimes which can be foliated by n-dimensional homogeneous subspaces, a quantum field can be decomposed in terms of modes on the subspaces, reducing the system to a collection of (D-n)-dimensional fields. This allows one to write bare D-dimensional field quantities like the Green function and the effective action as sums of their (D-n)-dimensional counterparts in the dimensionally reduced theory. It has been shown, however, that renormalization breaks this relationship between the original and dimensionally reduced theories, an effect called the dimensional-reduction anomaly. We examine the dimensional-reduction anomaly for the important case of spherically symmetric spaces.Comment: LaTeX, 19 pages, 2 figures. v2: calculations simplified, references adde

    Stellar Oscillations Network Group

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    Stellar Oscillations Network Group (SONG) is an initiative aimed at designing and building a network of 1m-class telescopes dedicated to asteroseismology and planet hunting. SONG will have 8 identical telescope nodes each equipped with a high-resolution spectrograph and an iodine cell for obtaining precision radial velocities and a CCD camera for guiding and imaging purposes. The main asteroseismology targets for the network are the brightest (V<6) stars. In order to improve performance and reduce maintenance costs the instrumentation will only have very few modes of operation. In this contribution we describe the motivations for establishing a network, the basic outline of SONG and the expected performance.Comment: Proc. Vienna Workshop on the Future of Asteroseismology, 20 - 22 September 2006. Comm. in Asteroseismology, Vol. 150, in the pres

    Electric Polarizability of Neutral Hadrons from Lattice QCD

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    By simulating a uniform electric field on a lattice and measuring the change in the rest mass, we calculate the electric polarizability of neutral mesons and baryons using the methods of quenched lattice QCD. Specifically, we measure the electric polarizability coefficient from the quadratic response to the electric field for 10 particles: the vector mesons ρ0\rho^0 and K∗0K^{*0}; the octet baryons n, Σ0\Sigma^0, Λo0\Lambda_{o}^{0}, Λs0\Lambda_{s}^{0}, and Ξ0\Xi^0; and the decouplet baryons Δ0\Delta^0, Σ∗0\Sigma^{*0}, and Ξ∗0\Xi^{*0}. Independent calculations using two fermion actions were done for consistency and comparison purposes. One calculation uses Wilson fermions with a lattice spacing of a=0.10a=0.10 fm. The other uses tadpole improved L\"usher-Weiss gauge fields and clover quark action with a lattice spacing a=0.17a=0.17 fm. Our results for neutron electric polarizability are compared to experiment.Comment: 25 pages, 20 figure
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