9,945 research outputs found

    Planning Guide Outdoor Recreation Facilities

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    Cross-Scale Energy Transport and Kinetic Wave Properties Associated with Kelvin-Helmholtz Instability

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    In the Earth’s magnetosphere, the magnetotail plasma sheet ions are much hotter than in the shocked solar wind. On the dawn-sector, the cold-component ions are more abundant and hotter by 30-40 percent when compared to the dusk sector. Recent statistical studies of the flank magnetopause and magnetosheath have shown that the level of temperature asymmetry of the magnetosheath is unable to account for this (Dimmock et al., 2015), so additional physical mechanisms must be at play, either at the magnetopause or plasma sheet, that contribute to this asymmetry. This thesis focuses on ion heating across the magnetopause boundary separating the magnetosheath and the magnetospheric plasmas, which is driven by mechanisms operating on fluid, ion and electron scales. One of the pending problems in collisionless astrophysical plasmas is to understand the plasma heating and transport across three fundamental scales: fluid, ion and electron. Presented here is evidence of the energy transport between the fluid and ion scales: energy is provided by a velocity shear at the magnetopause generating fluid-scale Kelvin-Helmholtz Instability and their rolled-up vortices, where an ion-scale fast magnetosonic wave packet located in the center of a Kelvin-Helmholtz vortex has sufficient energy to account for observed cold-component ion heating. In addition, a statistical analysis is performed on the ion-scale wave properties in the three main plasma regimes common to flank magnetopause boundary crossings when the boundary is unstable to KHI: hot and tenuous magnetospheric, cold and dense magnetosheath and mixed (H. Hasegawa, Fujimoto, Phan, et al., 2004). The statistical analysis shows that during KH events there is enhanced non-adiabatic heating calculated during ion scale wave intervals when compared to non-KH events. This suggests that during KH events there is more free energy for ion-scale wave generation, which in turn can heat ions more effectively when compared to cases when KH waves are absent. This may contribute to the dawn favored temperature asymmetry of the plasma sheet, because KH waves are statistically more abundant on the dawn sector. Furthermore, the present findings have universal consequences in understanding cross-scale energy transport from fluid to ion-scales, applicable to a variety of environments experiencing velocity shears with comparable plasma regimes

    The Angular Resolution of Space-Based Gravitational Wave Detectors

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    Proposed space-based gravitational wave antennas involve satellites arrayed either in an equilateral triangle around the earth in the ecliptic plane (the ecliptic-plane option) or in an equilateral triangle orbiting the sun in such a way that the plane of the triangle is tilted at 60 degrees relative to the ecliptic (the precessing-plane option). In this paper, we explore the angular resolution of these two classes of detectors for two kinds of sources (essentially monochromatic compact binaries and coalescing massive-black-hole binaries) using time-domain expressions for the gravitational waveform that are accurate to 4/2 PN order. Our results display an interesting effect not previously reported in the literature, and underline the importance of including the higher-order PN terms in the waveform when predicting the angular resolution of ecliptic-plane detector arrays.Comment: 13 pages, 6 figures, submitted to Phys Rev D. The current version corrects an error in our original paper and adds some clarifying language. The error also required correction of the graphs now shown in Figures 3 through

    An Earth Albedo Model: A Mathematical Model for the Radiant Energy Input to an Orbiting Spacecraft Due to the Diffuse Reflectance of Solar Radiation from the Earth Below

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    Past missions have shown that the earth's albedo can have a significant effect on the sun sensors used for spacecraft attitude control information. In response to this concern, an algorithm was developed to simulate this phenomenon, consisting of two parts, the physical model of albedo and its effect on the sun sensors. This paper contains the theoretical development of this model, practical operational notes, and its implementation in a FORTRAN subroutine

    Direct oral anticoagulants‐Remove versus Taipan snake venom time for detection of a lupus anticoagulant in patients taking oral direct factor Xa inhibitors

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    Background: The optimal method of detecting a lupus anticoagulant (LA) for patients taking direct factor Xa inhibitor (DFXaI) direct oral anticoagulants (DOACs) remains controversial. Methods include charcoal adsorption of the DOACs to allow testing with the activated partial thromboplastin time (APTT) and dilute Russell viper venom time (dRVVT), or use of the DFXaI‐insensitive Taipan snake venom time (TSVT) and Ecarin time (ET) assays on neat plasma. Objectives: The objective was to compare the utility of APTT and dRVVT analysis following DOAC Remove against TSVT/ET on untreated plasma for LA detection in spiked plasmas and routine clinical samples for patients on DFXaIs. Patients/methods: Various LA‐negative and LA‐positive samples were assayed by APTT, dRVVT, and TSVT/ET, and then separately spiked with rivaroxaban, apixaban, and edoxaban calibrators to a concentration of ~190 ng/ml and the assays repeated on spiked plasma before and after DOAC Remove treatment. Testing of 284 consecutive samples from DFXaI‐anticoagulated patients by APTT/dRVVT and TSVT/ET before and after DOAC Remove treatment was undertaken. Results: In the spiking model, we found that both TSVT/ET and DOAC Remove strategies generally distinguished LA‐negative and LA‐positive samples, but some false‐positive LA results occurred. In the investigation of 284 consecutive patient samples on DFXaIs, the percentage agreement for LA detection in neat samples tested by TSVT/ET versus APTT and dRVVT after DOAC Remove treatment was 90% (Cohen kappa 0.12). Conclusion: Our data highlight uncertainty and disagreement for testing LA in patients on DFXaI. Further studies are required

    Influence of wall vibrations on the sound of brass wind instruments

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    The results of an experimental and theoretical investigation of the influence of wall vibrations on the sound of brass wind instruments are presented. Measurements of the transmission function and input impedance of a trumpet, with the bell both heavily damped and freely vibrating, are shown to be consistent with a theory that assumes that the internal pressure causes an oscillation of the diameter of the pipe enclosing the air column. These effects are shown to be most significant in sections where there are flaring walls, which explains why damping these vibrations in cylindrical pipes normally produces no measurable effects

    Proposed Updates for Ap-42 Cotton Gin Emission Factors

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    A cotton ginning industry-supported project (National Study) was initiated in 2008 and completed in 2013 to collect additional particulate matter (PM) data for EPA's AP-42. PM stack emissions were collected using three EPA-approved methodologies and particle size analysis for 17 cotton gin systems. This study used the National Study and the 1996 AP-42 PM data and EPA's 2013 Emission Factor Development Procedures to develop suggested PM2.5, PM10, and total PM cotton gin emission factors, particle size distribution (PSD) characteristics, and evaluate EPA's development methodology. Unrepresentative test runs were removed from the National Study dataset for erratic gin operation, laboratory errors, or if the data was an outlier. Test runs were assign Individual Test Ratings (ITRs), ordered by descending "test" ITR for a given system, which was used to calculate Factor Quality Indices (FQI). If a "test" ITR increased the FQI, that "test" and those below it were excluded from the system emission factor calculation. Three "Test" Designs were evaluated to determine which was best for calculating emission factors and associated ratings. Test data ratings from the 1996 AP-42 were converted to ITRs and rerated with the ITR methodology to determine how that data should be handled. PSD data was evaluated for inclusion with EPA-approved emissions data. The optimal "Test" Design was determined to be one that used the average of all test runs from a single sampling method on a single system at a single facility as a "test." It was determined that the 1996 AP-42 data ratings should be rerated. PSD data should be combined with the section 9.7 emission factors. Final suggested typical gin emission factors were 0.0459 (0.1013), 0.4514 (0.9951), and 0.9404 kg/bale (2.0732 lb/bale) for PM2.5, PM10, and total PM, respectively. Final suggested typical gin PM10 and total PM emission factors were 22% higher and 14% lower than the 1996 AP-42 emission factors, respectively. Final suggested typical gin PM2.5, PM10, and total PM emission factors were 33, 22, and 0.81% lower than the National Study technical reports. Twelve, 53, and 71% of the final suggested PM2.5, PM10, and total PM emission factors rated "highly representative," respectively.Environmental Scienc

    The Optimal Single Copy Measurement for the Hidden Subgroup Problem

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    The optimization of measurements for the state distinction problem has recently been applied to the theory of quantum algorithms with considerable successes, including efficient new quantum algorithms for the non-abelian hidden subgroup problem. Previous work has identified the optimal single copy measurement for the hidden subgroup problem over abelian groups as well as for the non-abelian problem in the setting where the subgroups are restricted to be all conjugate to each other. Here we describe the optimal single copy measurement for the hidden subgroup problem when all of the subgroups of the group are given with equal a priori probability. The optimal measurement is seen to be a hybrid of the two previously discovered single copy optimal measurements for the hidden subgroup problem.Comment: 8 pages. Error in main proof fixe

    Homotransplantation of multiple visceral organs

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    It was technically possible to perform simultaneous homotransplantation of multiple visceral organs including the liver, spleen, pancreas, omentum and the entire gastrointestinal tract. Arterialization of the cooled graft was accomplished through the donor aorta which was removed with the graft and attached to that of the recipient dog. Gastrointestinal hemorrhage after surgery accounted for a high operative mortality and was thought to be due to denervation of the graft. The five dogs which survived the immediate trauma of surgery lived for five and a half to nine days. After the second day, these animals were physically active and able to resume oral alimentation. In three dogs, there was metabolic evidence of rejection of the liver. In two others, jaundice did not develop. These observations were compared with chemical, hematologic and pathologic data obtained in previous experiments involving homotransplantation of the liver alone. In some cases, there was less evidence of host versus graft rejection after the multiple organ transplants. Other data in the present study suggested the possibility that a significant graft versus host reaction may have been an important contributory cause of death. © 1962
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