188,387 research outputs found

    Recent Studies in Superconductivity at Extreme Pressures

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    Studies of the effect of high pressure on superconductivity began in 1925 with the seminal work of Sizoo and Onnes on Sn to 0.03 GPa and have continued up to the present day to pressures in the 200 - 300 GPa range. Such enormous pressures cause profound changes in all condensed matter properties, including superconductivity. In high pressure experiments metallic elements, Tc values have been elevated to temperatures as high as 20 K for Y at 115 GPa and 25 K for Ca at 160 GPa. These pressures are sufficient to turn many insulators into metals and magnetics into superconductors. The changes will be particularly dramatic when the pressure is sufficient to break up one or more atomic shells. Recent results in superconductivity to Mbar pressures wll be discussed which exemplify the progress made in this field over the past 82 years.Comment: Proceedings of the 21st AIRAPT and 45th EHPRG International Conference on High Pressure Science and Technology, Catania, Italy, Sept. 17-21, 200

    Constraining Post_Newtonian Parameters With Gravitational Waves

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    We re-express gravitational wave results in terms of post-Newtonian parameters. Using these expressions, and some simplifying assumptions, we compute that in a favorable case, i.e. a ten solar-mass black hole spiraling in to a 10^6 solar-mass black hole, LISA observations will be able to constrain at the 10% level or better a single combination of post-post-Newtonian parameters one order higher than those already constrained by solar system evidence. This significant constraint will be possible even if the signal-to-noise level is so low that the signal can only be found by matched filtering, and hence only deviations between alternate signal interpretations of order one half cycle or more can be detected.Comment: 8 pages, abbreviated version to be submitted to conference proceedings Twentieth Texas Symposium on Relativistic Astrophysics, Eds. J. Craig Wheeler and Hugo Marte

    "The Land of Liberty": Henry Bibb's Free Soil Geographies

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    This essay situates "The Narrative of the Life and Adventures of Henry Bibb, An American Slave" within the political context of the antislavery Free Soil movement, arguing that Bibb's representations of land and labor reflect the concerns of Free Soil. In particular, it argues that Bibb's narrative simultaneously critiques Free Soil ideology for its lack of a full-throated call for immediate abolition and its privileging of the white working class over both free and enslaved Black people. In addition, these aspects of Bibb’s Free Soil critique— both in condemning slavery and in reflexively challenging elements of Free Soil ideology—are more ecological than established Free Soil discourse, reflecting a deeper, more sensitive, and more radical understanding of material interconnection in regards to bodies, means of production, and topographies

    A herding perspective on global games and multiplicity

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    Recently, it has been claimed that full-information multiple equilibria in games with strategic complementarities are not robust, because generalizing to allow slightly heterogeneous information implies uniqueness. This paper argues that this "global games" uniqueness result is itself not robust. If we generalize by allowing most agents to observe a few previous actions before choosing, instead of forcing players to move exactly simultaneously, then multiplicity of outcomes is restored. Only a small sample of observations is needed to make our herding equilibrium behave like a full-information sunspot equilibrium instead of a global games equilibrium

    Education and Acculturation on Malaita: An Ethnography of Intraethnic and Interethnic Affinities

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    One of the central issues in educational anthropology is the changing nature of intraethnic and interethnic conflict and relationships. Conventional modernization theory suggests that the acculturation process will tend to diminish traditional allegiances and affinities. There are, however, indications that the opposite may occur. This essay reports on research into this issue undertaken on Malaita, in the Solomon Islands. The research method was sociometric and involved examination of the ethnic identity and affinities of individuals within the Malaitan language-groups, namely, the AreAre, Baegu, Baelelea, Dorio, Fataleka, Kwai Island, Kwaio, Kwara’ae, Langalanga, Lau, Sa’a and To’abaita language-groups. From this, I draw some conclusions on the acculturation process on Malaita, as well as what individuals in mass societies might learn from such language-group societies

    Goals of the ARISE Space VLBI Mission

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    Supermassive black holes, with masses of 10^6 to more than 10^9 solar masses, are among the most spectacular objects in the Universe, and are laboratories for physics in extreme conditions. The primary goal of ARISE (Advanced Radio Interferometry between Space and Earth) is to use the technique of Space VLBI to increase our understanding of black holes and their environments, by imaging the havoc produced in the near vicinity of the black holes by their enormous gravitational fields. The mission will be based on a 25-meter space-borne radio telescope operating at frequencies between 8 and 86 GHz, roughly equivalent to an orbiting element of the Very Long Baseline Array. In an elliptical orbit with an apogee height of 40,000-100,000 km, ARISE will provide resolution of 15 microarcseconds or better, 5-10 times better than that achievable on the ground. At frequencies of 43 and 86 GHz, the resolution of light weeks to light months in distant quasars will complement the gamma-ray and X-ray observations of high-energy photons, which come from the same regions near the massive black holes. At 22 GHz, ARISE will image the water maser disks in active galaxies more than 15 Mpc from Earth, probing accretion physics and giving accurate measurements of black-hole masses. ARISE also will study gravitational lenses at resolutions of tens of microarcseconds, yielding important information on the dark-matter distribution and on the possible existence of compact objects with masses of 10^3 to 10^6 solar masses.Comment: 6 pages, New Astronomy Reviews, Proceedings of 4th EVN/JIVE Symposium, LaTeX, document class elsart.cls, bibliography style natbib.st

    Age, growth and life history of Klamath River Basin steelhead trout (Onchorhynchus mykiss irideus) as determined from scale analysis

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    Adult steelhead (Oncorhynchus mykiss irideus) scales were analyzed from eight fall-run, two spring-run, and one winter-run stocks within the Klamath-Trinity River system, from 1981 through 1983, to provide basic information on age, growth, and life history. The higher degree of half-pounder occurrence of upper Klamath River steelhead stocks (86.7 to 100%) compared to Trinity River steelhead stocks (32.0 to 80.0%) was the major life history difference noted in scale analysis. Early life history was similar for all areas sampled with most juveniles (86.4%) remaining in freshwater during the first two years of life before migrating to sea. Repeat spawning ranged from 17.6 to 47.9% for fall-run, 40.0 to 63.6% for spring-run, and 31.1% for winter-run steelhead. Mean length of adults at first spawning was inversely related to percent half-pounder occurrence in each stock. Ages of returning spawners, back calculated lengths at various life stages, and growth information are presented. (PDF contains 22 pages
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