3,192 research outputs found

    Presidential Rhetoric at the United Nations: Cosmopolitan Discourse and the Management of International Relations

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    Despite longstanding attention to rhetorical form and structuring logics that give discourse its persuasive power (metaphor, genre, narrative, definitional frames, ideology, etc.), the relative amount of publication attending to international rhetoric remains slight. As the composition of audience(s) has stretched to global proportions the challenges of apprehending the manifold cross-cultural complexities for presidential address have expanded. Spanning five decades and three presidencies (Kennedy, H.W. Bush and Clinton), this dissertation takes presidential public address at the United Nations as its object of study in an effort to help remedy this shortcoming, while also aiming to provide a richer theoretical underpinning for accounts of globalization and its impact on the modern presidency. The analysis grapples with three particular problems: conceptualizing increasingly pluralized audiences, the matter of ascertaining how non-American institutions (like the United Nations) shape and are shaped by American rhetorical productions, and the difficulties in gauging presidential rhetorical efficacy. Two main arguments are advanced. First, the dissertation argues that presidential rhetoric at the United Nations traffics in a particular brand of cosmopolitanism, which helps presidents to constitute a universal audience nonetheless ideologically sympathetic to American goals. The terrain and implications of this cosmopolitanism rhetoric are mapped and unpacked. Second, it is argued that when crafting rhetoric for the specific audience of the United Nations General Assembly, the President is obligated to work within the confines of the rhetorical institution that is the United Nations. The project seeks to understand the limits and possibilities of presidential rhetoric based on existing international institutional constraints. Taken together, the resulting scene of presidential cosmopolitan address, rather than culminating in efforts primarily concentrated on persuasion, end up mainly interpellating a global audience supportive of a cosmopolitan agenda which in turn is pre-structured to support the interests of the United States

    A synchrotron study of Ba5Ta2Cl2O9

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    The structure of pentabarium ditantalum dichloride nonaoxide, Ba5Ta2Cl2O9, is isotypic with Ba5Ru1.6W0.4Cl2O9 and with one polymorph of Ba5Ru2Cl2O9. It is related to the perovskite structure and shows a ten-layer stacking of BaO3 and BaCl blocks along the c axis. The Ta cations occupy octahedral interstices, forming Ta2O9 dimers of distorted face-shared TaO6 octahedra. Except for one O atom, all atoms are situated on special positions: Ba1 (Wyckoff position (6) over bar m2), Ba2 and Ba3 (3m.), Ta (3m.), Cl (3m.) and O1 (mm2)

    Photonic band structure and emission characteristics of a metal-backed polymeric distributed feedback laser

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    Copyright © 2002 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 81 (2002) and may be found at http://link.aip.org/link/?APPLAB/81/954/1Optical losses associated with the metallic contacts necessary for charge injection are an obstacle to the development of an electrically pumped polymer laser. We show that it may be possible to overcome these losses by demonstrating the operation of a distributed-feedback polymer laser fabricated upon a silver substrate. The device lasing threshold was ~150 times greater than that of an otherwise similar metal-free device, though similar to early polymer lasers. The device emission characteristics correlated well with the measured photonic band structure, allowing an explanation of the effect of the microstructure on device operation

    Operating characteristics of a semiconducting polymer laser pumped by a microchip laser

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    Copyright © 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 82 (2003) and may be found at http://link.aip.org/link/?APPLAB/82/313/1We report the demonstration of a compact, all-solid-state polymer laser system featuring a microchip laser as the pump source. The laser was configured as a surface-emitting, two-dimensional distributed feedback laser, based on the conjugated polymer poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene). Pulsed, band-edge lasing was observed at 636 nm above a threshold pump energy of 4 nJ. The laser exhibited an energy slope efficiency of 6.8%, with a maximum output energy of 1.12 nJ at a pump energy of 20.4 nJ. The output beam had an azimuthally polarized annular profile with a beam quality factor (M2) of 2.2, close to the theoretical value of the lowest-order Laguerre–Gaussian and Bessel–Gaussian annular modes. We explain the origin of the azimuthal polarization as due to a coherent combination of the resonant fields supported by the two gratings

    A Gyrochronology and Microvariability Survey of the Milky Way's Older Stars Using Kepler's Two-Wheels Program

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    Even with the diminished precision possible with only two reaction wheels, the Kepler spacecraft can obtain mmag level, time-resolved photometry of tens of thousands of sources. The presence of such a rich, large data set could be transformative for stellar astronomy. In this white paper, we discuss how rotation periods for a large ensemble of single and binary main- sequence dwarfs can yield a quantitative understanding of the evolution of stellar spin-down over time. This will allow us to calibrate rotation-based ages beyond ~1 Gyr, which is the oldest benchmark that exists today apart from the Sun. Measurement of rotation periods of M dwarfs past the fully-convective boundary will enable extension of gyrochronology to the end of the stellar main-sequence, yielding precise ages ({\sigma} ~10%) for the vast majority of nearby stars. It will also help set constraints on the angular momentum evolution and magnetic field generation in these stars. Our Kepler-based study would be supported by a suite of ongoing and future ground-based observations. Finally, we briefly discuss two ancillary science cases, detection of long-period low-mass eclipsing binaries and microvariability in white dwarfs and hot subdwarf B stars that the Kepler Two-Wheels Program would facilitate.Comment: Kepler white pape

    Blue, surface-emitting, distributed feedback polyfluorene lasers

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    Copyright © 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 83 (2003) and may be found at http://link.aip.org/link/?APPLAB/83/2118/1We report the fabrication of optically-pumped solid-state distributed feedback lasers utilizing two blue-light-emitting semiconducting polyfluorenes as gain media. The lasers were readily fabricated by solution deposition of thin polymer films on top of gratings etched into fused silica substrates. A compact Nd:YVO4 microchip laser was used as the pump source for the two polymers studied, and lasing was achieved at 455 and 465 nm. Low threshold energies, ≥ 4 nJ per pulse, were obtained. The emission characteristics of the lasers are described along with the results of additional experiments that investigate in more detail the effect of the grating microstructure on polymer light emission

    Present and future evidence for evolving dark energy

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    We compute the Bayesian evidences for one- and two-parameter models of evolving dark energy, and compare them to the evidence for a cosmological constant, using current data from Type Ia supernova, baryon acoustic oscillations, and the cosmic microwave background. We use only distance information, ignoring dark energy perturbations. We find that, under various priors on the dark energy parameters, LambdaCDM is currently favoured as compared to the dark energy models. We consider the parameter constraints that arise under Bayesian model averaging, and discuss the implication of our results for future dark energy projects seeking to detect dark energy evolution. The model selection approach complements and extends the figure-of-merit approach of the Dark Energy Task Force in assessing future experiments, and suggests a significantly-modified interpretation of that statistic.Comment: 10 pages RevTex4, 3 figures included. Minor changes to match version accepted by PR
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