20,020 research outputs found

    Results of the jack mackerel subpopulation discrimination feasibility study

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    A report is made on the feasibility of discriminating subpopulations of jack mackerel, Trachurus symmetricus, off of the southern California and Baja California coast. Histochemical, morphometric, and meristic characters are compared from four samples of approximately 200 fish each taken from three areas. The data are analyzed for homogeneity by chi-square tests. Heterogeneity was found only in anal fin ray counts. Recommendations for a comprehensive study are made. (16pp.

    Results of Jack Mackerel tagging study, 1971-75

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    Methods and materials used to tag and recapture jack mackerel, Trachurus symmetricus, off the coast of southern Ca1ifornia and Baja California, Mexico, are described. Tagging, recapture, and movement data resulting from this program are reported. Analysis of these data indicates substantial movement of jack mackerel within the range of the California fishery and suggests a seasonal inshore-offshore movement pattern. (13pp.

    A simple test for thermomechanical evaluation of ceramic fibers

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    A simple bend stress relaxation (BSR) test was developed to measure the creep related properties of ceramic fibers and whiskers. The test was applied to a variety of commercial and developmental Si based fibers to demonstrate capabilities and to evaluate the relative creep resistance of the fibers at 1200 to 1400 C. The implications of these results and the advantages of the BSR test over typical tensile creep tests are discussed

    The Changing Behavior of the Term Structure of Interest Rates

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    We reexamine the expectations theory of the term structure using data at the short end of the maturity spectrum. We find that prior to the founding ofthe Federal Reserve System in 1915, the spread between long rates and short rates has substantial predictive power for the path of interest rates; after 1915, however, the spread contains much less predictive power. We then show that the short rate is approximately a random walk after the founding of the Fed but not before. This latter fact, coupled with even slight variation inthe term premium, can explain the observed change in 1915 in the performance of the expectations theory. We suggest that the random walk character of the short rate may be attributable to the Federal Reserve's commitment to stabilizing interest rates.

    The Adjustment of Expectations to a Change in Regime: A Study of the Founding of the Federal Reserve

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    The founding of the Federal Reserve System in 1914 led to a substantial change in the behavior of nominal interest rates. We examine the timing of this change and the speed with which it was effected. We then use data on the term structure of interest rates to determine how expectations responded. Our results indicate that the change in policy regime was rapid and that individuals quickly understood the new environment they were facing.

    Genome sequence of enterovirus D68 from St. Louis, Missouri, USA, 2016

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    Enterovirus D68 (EV-D68) was rarely observed prior to a widespread outbreak in 2014. We observed its reemergence in St. Louis in 2016 and sequenced the EV-D68 genomes from two patient samples. The 2016 viruses in St. Louis differed from those we had sequenced from the 2014 outbreak but were similar to other viruses circulating nationally in 2016

    The beginnings of geography teaching and research in the University of Glasgow: the impact of J.W. Gregory

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    J.W. Gregory arrived in Glasgow from Melbourne in 1904 to take up the post of foundation Professor of Geology in the University of Glasgow. Soon after his arrival in Glasgow he began to push for the setting up of teaching in Geography in Glasgow, which came to pass in 1909 with the appointment of a Lecturer in Geography. This lecturer was based in the Department of Geology in the University's East Quad. Gregory's active promotion of Geography in the University was matched by his extensive writing in the area, in textbooks, journal articles and popular books. His prodigious output across a wide range of subject areas is variably accepted today, with much of his geomorphological work being judged as misguided to varying degrees. His 'social science' publications - in the areas of race, migration, colonisation and economic development of Africa and Australia - espouse a viewpoint that is unacceptable in the twenty-first century. Nonetheless, that viewpoint sits squarely within the social and economic traditions of Gregory's era, and he was clearly a key 'Establishment' figure in natural and social sciences research in the first half of the twentieth century. The establishment of Geography in the University of Glasgow remains enduring testimony of J.W. Gregory's energy, dedication and foresight

    Melting of cognetic depleted and enriched reservoirs and the production of high Ti Mare basalts

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    Implicit in current understanding of the location of terrestrial enriched and depleted reservoirs is the notion that they are spatially separated. The depleted reservoir on Earth is situated in the upper mantle, and the complementary enriched reservoir is located in the crust. However, Earth reservoirs are continually being modified by recycling driven by mantle convection. The Moon is demonstrably different from Earth in that its evolution was arrested relatively early - effectively with 1.5 Ga of its formation. It is possible that crystallized trapped liquids (from the late stages of a magma ocean) have been preserved as LILE-enriched portions of the lunar mantle. This would lead to depleted (cumulate) and enriched (magma ocean residual liquid) reservoirs in the lunar upper mantle. There is no evidence for significant recycling from the highland crust back into the mantle. Therefore, reservoirs created at the Moon's inception may have remained intact for over 4.0 Ga. The topics discussed include the following: (1) radiogenic isotopes in high-Ti mare basalts; (2) formation of cogenetic depleted and enriched reservoirs; and (3) melting of the source to achieve high-Ti mare basalts

    Entanglement Entropy and Full Counting Statistics for 2d2d-Rotating Trapped Fermions

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    We consider NN non-interacting fermions in a 2d2d harmonic potential of trapping frequency ω\omega and in a rotating frame at angular frequency Ω\Omega, with 0<ω−Ω≪ω0<\omega - \Omega\ll \omega. At zero temperature, the fermions are in the non-degenerate lowest Landau level and their positions are in one to one correspondence with the eigenvalues of an N×NN\times N complex Ginibre matrix. For large NN, the fermion density is uniform over the disk of radius N\sqrt{N} centered at the origin and vanishes outside this disk. We compute exactly, for any finite NN, the R\'enyi entanglement entropy of order qq, Sq(N,r)S_q(N,r), as well as the cumulants of order pp, ⟨Nrp⟩c\langle{N_r^{p}}\rangle_c, of the number of fermions NrN_r in a disk of radius rr centered at the origin. For N≫1N \gg 1, in the (extended) bulk, i.e., for 0<r/N<10 < r/\sqrt{N} < 1, we show that Sq(N,r)S_q(N,r) is proportional to the number variance Var (Nr){\rm Var}\,(N_r), despite the non-Gaussian fluctuations of NrN_r. This relation breaks down at the edge of the fermion density, for r≈Nr \approx \sqrt{N}, where we show analytically that Sq(N,r)S_q(N,r) and Var (Nr){\rm Var}\,(N_r) have a different rr-dependence.Comment: 6 pages + 7 pages (Supplementary material), 2 Figure

    Debris/ice/TPS assessment and integrated photographic analysis for Shuttle Mission STS-54

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    A Debris/Ice/TPS assessment and integrated photographic analysis was conducted for Shuttle Mission STS-54. Debris inspections of the flight elements and launch pad were performed before and after launch. Ice/frost conditions on the External Tank were assessed by the use of computer programs, nomographs, and infrared scanner data during cryogenic loading of the vehicle followed by on-pad visual inspection. High speed photography was analyzed after launch to identify ice/debris sources and evaluate potential vehicle damage and/or in-flight anomalies. This report documents the debris/ice/TPS conditions and integrated photographic analysis of Shuttle Mission STS-54, and the resulting effect on the Space Shuttle Program
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