12,514 research outputs found

    Fault Slip and Exhumation History of the Willard Thrust Sheet, Sevier Fold‐Thrust Belt, Utah: Relations to Wedge Propagation, Hinterland Uplift, and Foreland Basin Sedimentation

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    Zircon (U‐Th)/He (ZHe) and zircon fission track thermochronometric data for 47 samples spanning the areally extensive Willard thrust sheet within the western part of the Sevier fold‐thrust belt record enhanced cooling and exhumation during major thrust slip spanning approximately 125–90 Ma. ZHe and zircon fission track age‐paleodepth patterns along structural transects and age‐distance relations along stratigraphic‐parallel traverses, combined with thermo‐kinematic modeling, constrain the fault slip history, with estimated slip rates of ~1 km/Myr from 125 to 105 Ma, increasing to ~3 km/Myr from 105 to 92 Ma, and then decreasing as major slip was transferred onto eastern thrusts. Exhumation was concentrated during motion up thrust ramps with estimated erosion rates of ~0.1 to 0.3 km/Myr. Local cooling ages of approximately 160–150 Ma may record a period of regional erosion, or alternatively an early phase of limited... (see full abstract in article)

    K-causality and degenerate spacetimes

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    The causal relation K+K^+ was introduced by Sorkin and Woolgar to extend the standard causal analysis of C2C^2 spacetimes to those that are only C0C^0. Most of their results also hold true in the case of spacetimes with degeneracies. In this paper we seek to examine K+K^+ explicitly in the case of Lorentzian topology changing Morse spacetimes containing isolated degeneracies. We first demonstrate some interesting features of this relation in globally Lorentzian spacetimes. In particular, we show that K+K^+ is robust and that it coincides with the Seifert relation when the spacetime is stably causal. Moreover, the Hawking and Sachs characterisation of causal continuity translates into a natural expression in terms of K+K^+ for general spacetimes. We then examine K+K^+ in topology changing Morse spacetimes both with and without the degeneracies and find further characterisations of causal continuity.Comment: Latex, 23 pages, 4 figure

    Collisional damping rates for plasma waves

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    The distinction between the plasma dynamics dominated by collisional transport versus collective processes has never been rigorously addressed until recently. A recent paper [Yoon et al., Phys. Rev. E 93, 033203 (2016)] formulates for the first time, a unified kinetic theory in which collective processes and collisional dynamics are systematically incorporated from first principles. One of the outcomes of such a formalism is the rigorous derivation of collisional damping rates for Langmuir and ion-acoustic waves, which can be contrasted to the heuristic customary approach. However, the results are given only in formal mathematical expressions. The present Brief Communication numerically evaluates the rigorous collisional damping rates by considering the case of plasma particles with Maxwellian velocity distribution function so as to assess the consequence of the rigorous formalism in a quantitative manner. Comparison with the heuristic ("Spitzer") formula shows that the accurate damping rates are much lower in magnitude than the conventional expression, which implies that the traditional approach over-estimates the importance of attenuation of plasma waves by collisional relaxation process. Such a finding may have a wide applicability ranging from laboratory to space and astrophysical plasmas.Comment: 5 pages, 2 figures; Published in Physics of Plasmas, volume/Issue 23/6. Publisher: AIP Publishing LLC. Date: Jun 1, 2016. URL: http://aip.scitation.org/doi/10.1063/1.4953802 Rights managed by AIP Publishing LL

    Crit II Electric, Magnetic, and Density Measurements Within an Ionizing Neutral Stream

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    Measurements from rocket borne sensors inside a high velocity neutral barium beam show a factor of six increasei n plasmad ensityi n a movingi onizingf ront. This region-wacso -locatedw ith intensef luctuatinge lectric fields( $E • 300m V/m) at frequenciewse llu ndert he lower hybrid frequency for a barium plasina. Large quasi-DC electric and magnetic field fluctuations were also detected with a large componento f the current and the electricf ield. parallelt o Bo. An Alfv6n wavew ith a finite electricf ield componentp arallel to the geomagneticfi eld was observed to propagatea longB o, wherei t wasd etectedb y ami nstrumented sub-payload

    Observation of photo-thermal feed-back in a stable dual-carrier optical spring

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    We report on the observation of photo-thermal feed-back in a stable dual-carrier optical spring. The optical spring is realized in a 7 cm Fabry-Perot cavity comprised of a suspended 0.4 g small end mirror and a heavy input coupler, illuminated by two optical fields. The frequency, damping and stability of the optical spring resonance can be tuned by adjusting the power and detuning of the two optical fields, allowing for a precise measurement of the absorption-induced photo-thermal feedback. The magnitude and frequency dependence of the observed photo-thermal effect are consistent with predicted corrections due to transverse thermal diffusion and coating structure. While the observed photo-thermal feed-back tends to destabilize the optical spring, we also propose a small coating modification that would change the sign of the effect, making a single-carrier stable optical spring possible

    Searching for keV Sterile Neutrino Dark Matter with X-ray Microcalorimeter Sounding Rockets

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    High-resolution X-ray spectrometers onboard suborbital sounding rockets can search for dark matter candidates that produce X-ray lines, such as decaying keV-scale sterile neutrinos. Even with exposure times and effective areas far smaller than XMM-Newton and Chandra observations, high-resolution, wide field-of-view observations with sounding rockets have competitive sensitivity to decaying sterile neutrinos. We analyze a subset of the 2011 observation by the X-ray Quantum Calorimeter instrument centered on Galactic coordinates l = 165, b = -5 with an effective exposure of 106 seconds, obtaining a limit on the sterile neutrino mixing angle of sin^2(2 theta) < 7.2e-10 at 95% CL for a 7 keV neutrino. Better sensitivity at the level of sin^2(2 theta) ~ 2.1e-11 at 95\% CL for a 7 keV neutrino is achievable with future 300-second observations of the galactic center by the Micro-X instrument, providing a definitive test of the sterile neutrino interpretation of the reported 3.56 keV excess from galaxy clusters.Comment: 13 pages, 13 figures, submitted to Ap

    Assessment Of A State Commodity Marketing Program: A Case Study Approach Using 2003-2004 Texas Wine Marketing Assistance Program Evaluation

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    The Texas wine industry is a growing industry that impacts the states economy, offers gains in tourism and provides Texas jobs.  This study shows the gains recognized from Texas Wineries during their participation (2004 fiscal year) in the Texas Wine Marketing Assistance Program (TWMAP) with comparisons made to the initial assessment for 2002 fiscal year.  A questionnaire was created to assess the benefits to the wineries of the state of Texas which participated in the TWMAP program.  When compared to the initial assessment (2002), participating wineries experienced an increase in all categories, for example, average sales, number of wineries participating in the program and visits to the wineries.  A greater number of wineries participated in the programs, and a higher percentage believed that the TWMAP was beneficial to their business.  Thirty percent more wineries reported sales increases, (67% in 2003, 97% in 2004) with average sales increase from 88,983in2003to88,983 in 2003 to 109,387 in 2004 creating a total economic impact increase from 4.1millionto4.1 million to 10.1 million.  The ROI increased from 930% to 1,400%. The participants in the TWMAP attribute 35.4% of their sales increases directly to the TWMAP, amounting to 3.57millionineconomicbenefitforthestate,withprogrammingcostsof3.57 million in economic benefit for the state, with programming costs of 250,000.  The TWMAP returned over 14foreach14 for each 1 of state funds invested, or 1,400% return on state funding.  This was an increase in the already impressive 930% increase in returns reported in 2002.  In light of these trends in this program, it is clear that the TWMAP is establishing a pattern of success and the existence of a marketing campaign has had a successful economic impact on the growth of the Texas wine industry.
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