2,496 research outputs found

    A Spin-Orbit Alignment for the Hot Jupiter HATS-3b

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    We have measured the alignment between the orbit of HATS-3b (a recently discovered, slightly inflated Hot Jupiter) and the spin-axis of its host star. Data were obtained using the CYCLOPS2 optical-fiber bundle and its simultaneous calibration system feeding the UCLES spectrograph on the Anglo-Australian Telescope. The sky-projected spin-orbit angle of λ=3±25\lambda = 3\pm25^{\circ} was determined from spectroscopic measurements of Rossiter-McLaughlin effect. This is the first exoplanet discovered through the HATSouth transit survey to have its spin-orbit angle measured. Our results indicate that the orbital plane of HATS-3b is consistent with being aligned to the spin axis of its host star. The low obliquity of the HATS-3 system, which has a relatively hot mid F-type host star, agrees with the general trend observed for Hot Jupiter host stars with effective temperatures >6250>6250K to have randomly distributed spin-orbit angles.Comment: 13 pages. Accepted for publication in the Astrophysical Journa

    A Nearly Polar Orbit for the Extrasolar Hot Jupiter WASP-79b

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    We report the measurement of a spin-orbit misalignment for WASP-79b, a recently discovered, bloated transiting hot Jupiter from the WASP survey. Data were obtained using the CYCLOPS2 optical-fiber bundle and its simultaneous calibration system feeding the UCLES spectrograph on the Anglo-Australian Telescope. We have used the Rossiter-McLaughlin effect to determine the sky-projected spin-orbit angle to be lambda = -106+19-13 degrees. This result indicates a significant misalignment between the spin axis of the host star and the orbital plane of the planet -- the planet being in a nearly polar orbit. WASP-79 is consistent with other stars that have Teff > 6250K and host hot Jupiters in spin-orbit misalignment.Comment: 8 pages, 2 figures, in press ApJL (accepted 2 August 2013

    Coarse-graining diblock copolymer solutions: a macromolecular version of the Widom-Rowlinson model

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    We propose a systematic coarse-grained representation of block copolymers, whereby each block is reduced to a single ``soft blob'' and effective intra- as well as intermolecular interactions act between centres of mass of the blocks. The coarse-graining approach is applied to simple athermal lattice models of symmetric AB diblock copolymers, in particular to a Widom-Rowlinson-like model where blocks of the same species behave as ideal polymers (i.e. freely interpenetrate), while blocks of opposite species are mutually avoiding walks. This incompatibility drives microphase separation for copolymer solutions in the semi-dilute regime. An appropriate, consistent inversion procedure is used to extract effective inter- and intramolecular potentials from Monte Carlo results for the pair distribution functions of the block centres of mass in the infinite dilution limit.Comment: To be published in mol.phys(2005

    Use of the short-term inflammatory response in the mouse peritoneal cavity to assess the biological activity of leached vitreous fibers.

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    We used a special-purpose glass microfiber sample, Johns-Manville Code 100/475, to study the effects of various acid and alkali treatments on biological activity as assessed by inflammation in the mouse peritoneal cavity, the leaching of Si, and the phase contrast optical microscopy (PCOM) fiber number. We used mild and medium treatments with oxalic acid and Tris buffer and harsh treatment with concentrated HCl and NaOH. Mild oxalic acid and Tris treatment for 2 weeks had no effect on any of the end-points, but prolonging the mild oxalic acid treatment time to 2 months reduced the biological activity and the fiber number. Medium oxalic acid treatment reduced the biological activity and the fiber number and caused a loss of Si. Medium Tris alkali treatment reduced the PCOM-countable fibers and the biological activity but did not cause a substantial loss of Si. Harsh treatment with strong HCl did not affect the fiber number or cause leaching but the biological activity was reduced; strong NaOH reduced the fiber number and biological activity, and caused marked leaching of Si. The medium oxalic acid conditions (pH 1.4) were more acid than those found in lung cells but produced the same effects (reduction in fiber number and biological activity) as the more physiological mild treatment (pH 4.0), when prolonged. This study suggests that medium oxalic acid treatment can be used as a short-term assay to compare loss of Si, reduction in fiber number, and change in biological activity of vitreous fibers.(ABSTRACT TRUNCATED AT 250 WORDS

    Risk Prediction Scores for Postoperative Mortality After Esophagectomy: Validation of Different Models

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    Background: Different prediction models for operative mortality after esophagectomy have been developed. The aim of this study is to independently validate prediction models from Philadelphia, Rotterdam, Munich, and the ASA. Methods: The scores were validated using logistic regression models in two cohorts of patients undergoing esophagectomy for cancer from Switzerland (n = 170) and Australia (n = 176). Results: All scores except ASA were significantly higher in the Australian cohort. There was no significant difference in 30-day mortality or in-hospital death between groups. The Philadelphia and Rotterdam scores had a significant predictive value for 30-day mortality (p = 0.001) and in-hospital death (p = 0.003) in the pooled cohort, but only the Philadelphia score had a significant prediction value for 30-day mortality in both cohorts. Neither score showed any predictive value for in-hospital death in Australians but were highly significant in the Swiss cohort. ASA showed only a significant predictive value for 30-day mortality in the Swiss. For in-hospital death, ASA was a significant predictor in the pooled and Swiss cohorts. The Munich score did not have any significant predictive value whatsoever. Conclusion: None of the scores can be applied generally. A better overall predictive score or specific prediction scores for each country should be develope

    Test Bed for Quantitative NDE

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    The ARPA/AFML Interdisciplinary Program for Quantitative Flaw Definition has demonstrated a number of new techniques for quantitatively sizing flaws, as are reported elsewhere in these proceedings. This paper describes the progress that has been made during the past year on a test bed program to assemble and demonstrate these techniques in a single integrated measurement system that will extend them from the idealized geometries that have been considered thus far to geometries that are a better approximation to those that are found in real parts. The basic system consists of a Data General Eclipse S/200 Minicomputer, a multiaxis microprocessor controller, a Biomation A/D converter, an immersion tank, and a contour following system with six degrees of freedom. The operation of the mechanical system with regard to its accuracy and repeatability will be described. In addition, a review of the conceptual design of the test bed system and experimental results for a number of different flaw geometries will be included. The Test Bed includes a piezoelectric array transducer and associated electronics. The array system will be used both for the imaging of flaws and the gathering of scattering data to use in other flaw characterization algorithms. The success of this portion of the program depends to a large extent on the availability of a suitable array transducer. Some difficulty has been met in obtaining such a transducer and the system design has been slightly modified as a result. The modified system will be described along with a review of the electronic system and an update on its current status. The extended data gathering capability of the system has been demonstrated with several diffusion bonded samples containing spherical and spheroidal voids. The noise associated with these signals is chiefly due. to the grain scattering and varies in amplitude over a wide range. The effects of this noise on the accuracy of the Inverse Born Approximation has been analyzed and the results will be summarized
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