118,579 research outputs found

    Detailed characterization of the early x-ray emission of a plasma produced by point-like laser irradiation of solid Al targets

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    A study of the dynamics of the x-ray emission from a point-like Al plasma produced by tight-focusing laser irradiation of a thick target is reported. Two-dimensional maps of the x-ray emission calculated at selected wavelengths show that, due to the rapid expansion cooling, x-ray emission mostly originates from a thin spatial layer. These properties enabled the results of the simulations to be compared with time-resolved x-ray spectra obtained under well-controlled experimental conditions. The outcome of this comparison is discussed in details, in view of the results reported in a recently published Letter [L. A. Gizzi, C. A. Cecchetti, M. Galimberti, A. Giulietti, D. Giulietti, L. Labate, S. Laville, and B. Tomassini, Phys. Plasmas 10, 4601 (2003)]. Moreover, the x-ray-reabsorption issues and the role of the Doppler decoupling mechanism in the presence of the strong velocity gradient typical of our experimental condition are discussed, also in view of a possible dedicated experiment. (c) 2005 American Institute of Physics

    Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?

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    In this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association

    Localizzazione immunoistochimica delle cellule a MSH nell’ipofisi di pesce spada (Xiphias gladius L.).

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    Pituitary MSH cels were immunohistochemically localized in the teleost fish Xiphias gladius L. using anti a-MSH polydonal serum. MSH cells were found mainly in the pars intermedia (PI) and scarsety in the PD. The density of MSH cells showed difference related to sex and size ofspecimens

    Letter from unknown writer to Jesse L. Boyce

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    Letter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County

    The surface admittance equivalence principle for cloaking problems

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    In this paper, we apply a reformulated version of the Surface Equivalence Principle, originally defined for radiating phenomena in terms of tangential fields, to cloaking problems in terms of admittance functions at an arbitrary boundary. In order to cloak a dielectric/metallic object, the tangential fields ratio (admittance) can be controlled at any arbitrary attached/detached surface boundary. The dispersive surface admittance cloak, as originally introduced for Mantle Cloaking, is computed in a closed-form solution at any frequency regime (quasi-static and beyond)

    Letter from Carl Hayden to L. L. Ferrall, Postmaster at Grand Canyon

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    Letter from Carl Hayden to L. L. Ferrall on the favorable conditions for creating a national park and the prospect of the United States entering WW I
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