11,228 research outputs found

    Research in the development effort of an improved multiplier phototube final report

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    Single electron counting characteristics of multiplier phototubes - Pulse height distribution of windowless multiplie

    Research in the development effort of an improved multiplier phototube Seventh quarterly report

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    Test data on effective photocathode size, response uniformity, and pulse amplitude distribution of multiplier phototube

    Research in the development of an improved multiplier phototube Final report

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    Cascade aperture design, gas pressure effects, gain calibration, and photon counting efficiency of multiplier phototub

    Research in the development of an improved multiplier phototube

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    Parameters in analog /dc/ and digital /single electron pulse count/ modes of processing data from photomultiplier tube

    Ibuprofen as a Treatment for Work-Related Musculoskeletal Disorders: Effectiveness versus Caveats

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    Work-related upper limb disorders (WMSDs), also known as repetitive strain injuries, affect a large subsection of the US population. These disorders are a significant source of injury, morbidity, loss of work, and pain. We have developed a rat model of upper extremity repetitive work at high forces, and observed exposure-dependent increased inflammatory responses in all tissues involved in performing the task. A 2- to 8-week regimen of oral ibuprofen provided to rats while they continued to perform a high-repetition high-force task ameliorated these inflammatory responses as well as several motor declines. Ibuprofen treatment also attenuated task-induced tissue fibrosis, cartilage degeneration, and bone osteopenia, indicating their link to inflammatory processes. However, ibuprofen did not significantly attenuate persistent nocifensive pain behaviors (reflexive grip strength results are presented) likely because of persistent increases in inflammatory cytokines in the spinal cord, suggestive of central sensitization. Since long-term ibuprofen use can induce a number of negative side effects, such as gastritis, multi-pronged approaches should be considered with anti-inflammatory drugs included for only short time periods

    Are the distributions of Fast Radio Burst properties consistent with a cosmological population?

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    High time resolution radio surveys over the last few years have discovered a population of millisecond-duration transient bursts called Fast Radio Bursts (FRBs), which remain of unknown origin. FRBs exhibit dispersion consistent with propagation through a cold plasma and dispersion measures indicative of an origin at cosmological distances. In this paper we perform Monte Carlo simulations of a cosmological population of FRBs, based on assumptions consistent with observations of their energy distribution, their spatial density as a function of redshift and the properties of the interstellar and intergalactic media. We examine whether the dispersion measures, fluences, inferred redshifts, signal-to-noises and effective widths of known FRBs are consistent with a cosmological population. Statistical analyses indicate that at least 50 events at Parkes are required to distinguish between a constant co-moving FRB density, and a FRB density that evolves with redshift like the cosmological star formation rate density.Comment: 11 pages, 7 figures, 3 table

    Preliminary investigation of a major high-strain zone in the Caledonian Highlands, southern New Brunswick

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    A major ductile high-strain zone up to 5 km in width can be traced for at least 70 km diagonally across the Avalonian Caledonia terrane of southern New Brunswick. A study of the northeastern part of this zone from the Prosser Mountain area in the northwest to the Point Wolfe River area west of Fundy National Park shows that both the ca. 630-620 Ma Broad River Group and associated plutons and the 560-550 Ma Coldbrook Group contain similar structural elements, related to a largely shared deformational history. Some of this history is apparent also in the 560–550 Ma plutonic rocks. A pervasive foliation (S1) lies parallel to bedding (S0), and although evidently composite (S0-1) in the Broad River Group, this fabric is very heterogeneous in the younger Coldbrook Group, where low strain enclaves are widespread. No folds have been seen of an F1 generation, and no reversals of facing or vergence are apparent. A mineral lineation (L1m) is locally prominent. The plutonic rocks have early fabrics, including a foliation (S1) producing augen-gneiss with a prominent L-tectonite (L1m). S1 also includes a schistosity associated with the growth of white mica and breakdown of feldspar. Geometry suggests that S1 in the granites is related to S0-1 in the supracrustal rocks, and L1m in both units shares a common orientation. S1 and S0-1 are crenulated by a strong second cleavage (S2) axial planar to folds (F2), the large-scale expression of which is an asymmetric synform containing a belt of Coldbrook Group rocks. Kinematic indicators suggest an overall top-to-the-SE motion along thrusts that stack units of Broad River Group, Coldbrook Group, and plutonic rocks. Fabric development in the plutonic rocks implies a history of exhumation beginning under hot, anhydrous conditions, followed by hydration during retrogression as plutonic rocks were tectonically emplaced into this crustal stack. The age of these tectonic events is not yet well constrained, but could be as young as Carboniferous. RÉSUMÉ Il est possible de retracer une importante zone de forte contrainte ductile ayant jusqu’à cinq kilomètres de largeur sur une distance de 70 kilomètres en diagonale à travers le terrane avalonien de Caledonia, dans le Sud du Nouveau-Brunswick. Une étude de la partie nord-est de cette zone à partir du secteur du mont Prosser, dans le nord-ouest, jusqu’au secteur de la rivière Pointe Wolfe, à l’ouest du parc national du Canada Fundy, révèle que le groupe d’environ 630 à 620 Ma de la rivière Broad, les plutons connexes et le groupe de 560 à 550 Ma de Coldbrook abritent des éléments structuraux similaires, apparentés à des déformations passées largement partagées. Une certaine partie de ce passé est également apparente dans les roches plutoniques de 560 à 550 Ma. Une foliation intense (S1) se manifeste parallèlement à la stratification (S0) et, même si cette fabrique est nettement composite (S0-1) dans le groupe de la rivière Broad, elle est très hétérogène dans le groupe plus récent de Coldbrook, où les enclaves de faible contrainte sont répandues. On n’a observé aucun pli d’une production F1 et aucune inversion du regard ni de la vergence n’est apparente. Une linéation minérale (L1m), définie par des agrégats de biotite, est localement bien visible. Les roches plutoniques possèdent des fabriques qui se sont constituées pendant et peu après la cristallisation, notamment une foliation (S1) produisant du gneiss oeillé avec L-tectonite (L1m) en évidence. S1 à l’intérieur des roches plutoniques comporte en outre une schistosité associée à la croissance de mica blanc et à la décomposition de feldspath. La géométrie permet de supposer que S1 dans les granites est apparentée à S0-1 dans les roches supracrustales et que la linéation minérale (L1m) dans les deux unités partage une orientation commune. S1 et S0-1 sont crénelés par une seconde schistosité (S2) prononcée, de plan axial par rapport aux plis (F2), dont l’expression à grande échelle est une synforme asymétrique renfermant une ceinture de roches du groupe de Coldbrook. Les indicateurs cinématiques des structures F2 permettent de supposer un mouvement général du sommet vers le sud-est le long des chevauchements qui empilent les unités du groupe de la rivière Broad, du groupe de Coldbrook et des roches plutoniques. Le développement de la fabrique dans les roches plutoniques plus âgées suppose une exhumation passée ayant commencé dans des conditions très chaudes et anhydres pendant et peu après la cristallisation, vers 620 Ma, suivie par une hydratation pendant la rétrogression au moment où les roches plutoniques se sont tectoniquement mises en place à l’intérieur de cet éperon crustal. L’âge des événements tectoniques tardifs n’est pas encore bien circonscrit, mais ils pourraient remonter au Carbonifère. [Traduit par la redaction

    Probing the Inflow/Out-flow and Accretion Disk of Cyg X-1 in the High State with HETG/Chandra

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    Cyg X-1 was observed in the high state at the conjunction orbital phase (0) with HETG/Chandra. Strong and asymmetric absorption lines of highly ionized species were detected, such as Fe XXV, Fe XXIV, Fe XXIII, Si XIV, S XVI, Ne X, and etc. In the high state the profile of the absorption lines are composed of an extended red wing and a less extended blue wing. The red wings of higher ionized species are more extended than that of lower ionized species. The detection of these lines provides a way to probe the properties of the flow around the companion and the black hole in Cyg X-1 during the high state. A broad emission feature around 6.5 keV was significantly detected from the both spectra of HETG/Chandra and PCA/RXTE. This feature appears to be symmetric and can be fitted with a Gaussian function rather than the Laor disk line model of fluorescent Fe Kα_\alpha line from an accretion disk. The implications of these results on the structure of the accretion flow of Cyg X-1 in the high state are discussed.Comment: 16 pages, 4 fiugres. accepted for publication in the v597 n2 ApJ November 10, 2003 issu
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