3,297 research outputs found

    Performance characteristics of wind profiling radars

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    Doppler radars used to measure winds in the troposphere and lower stratosphere for weather analysis and forecasting are lower-sensitivity versions of mesosphere-stratosphere-troposphere radars widely used for research. The term wind profiler is used to denote these radars because measurements of vertical profiles of horizontal and vertical wind are their primary function. It is clear that wind profilers will be in widespread use within five years: procurement of a network of 30 wind profilers is underway. The Wave Propagation Laboratory (WPL) has operated a small research network of radar wind profilers in Colorado for about two and one-half years. The transmitted power and antenna aperture for these radars is given. Data archiving procedures have been in place for about one year, and this data base is used to evaluate the performance of the radars. One of the prime concerns of potential wind profilers users is how often and how long wind measurements are lacking at a given height. Since these outages constitute an important part of the performance of the wind profilers, they are calculated at three radar frequencies, 50-, 405-, and 915-MHz, (wavelengths of 6-, 0.74-, and 0.33-m) at monthly intervals to determine both the number of outages at each frequency and annual variations in outages

    Connecting the discrete and continuous-time quantum walks

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    Recently, quantized versions of random walks have been explored as effective elements for quantum algorithms. In the simplest case of one dimension, the theory has remained divided into the discrete-time quantum walk and the continuous-time quantum walk. Though the properties of these two walks have shown similarities, it has remained an open problem to find the exact relation between the two. The precise connection of these two processes, both quantally and classically, is presented. Extension to higher dimensions is also discussed.Comment: 5 pages, 1 figur

    A Case Study of Fall versus Spring Calving for the Rocky Mountain West

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    Feeder cattle prices are generally lower in the fall, when the volume of calves for sale is highest. Most ranches in the Rocky Mountains calve in March or April, which results in the sale of weaned calves in October, when feeder cattle prices tend to be lowest. This study was initiated with the idea that a rancher might improve profitability by switching to fall calving, which would enable them to sell calves in April at a higher price. In this study, fall calving generated both higher and less variable profit, but mainly because of cost savings.Livestock Production/Industries,

    Quantum Walks on Trees with Disorder: Decay, Diffusion, and Localization

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    Quantum walks have been shown to have impressive transport properties compared to classical random walks. However, imperfections in the quantum walk algorithm can destroy any quantum mechanical speed-up due to Anderson localization. We numerically study the effect of static disorder on a quantum walk on the glued trees graph. For small disorder, we find that the dominant effect is a type of quantum decay, and not quantum localization. For intermediate disorder, there is a crossover to diffusive transport, while a localization transition is observed at large disorder, in agreement with Anderson localization on the Cayley tree.Comment: 12 pages, 13 figure

    Nuclear Quasi-Elastic Electron Scattering Limits Nucleon Off-Mass Shell Properties

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    The use of quasi-elastic electron nucleus scattering is shown to provide significant constraints on models of the proton electromagnetic form factor of off-shell nucleons. Such models can be constructed to be consistent with constraints from current conservation and low-energy theorems, while also providing a contribution to the Lamb shift that might potentially resolve the proton radius puzzle in muonic hydrogen. However, observations of quasi-elastic scattering limit the overall strength of the off-shell form factors to values that correspond to small contributions to the Lamb shift.Comment: 11 pages, 2 figures. Resubmission to improve the clarity, and correct possible misconception

    Quantum logic gates for superconducting resonator qudits

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    We study quantum information processing using superpositions of Fock states in superconducting resonators, as quantum dd-level systems (qudits). A universal set of single and coupled logic gates is theoretically proposed for resonators coupled by superconducting circuits of Josephson juctions. These gates use experimentally demonstrated interactions, and provide an attractive route to quantum information processing using harmonic oscillator modes.Comment: 10 pages, 14 figures, decoherence calculations adde

    Evidence for Δ(2200)7/2−\Delta(2200)7/2^- from photoproduction and consequence for chiral-symmetry restoration at high mass

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    We report a partial-wave analysis of new data on the double-polarization variable EE for the reactions γp→π+n\gamma p\to \pi^+ n and γp→π0p\gamma p\to \pi^0 p and of further data published earlier. The analysis within the Bonn-Gatchina (BnGa) formalism reveals evidence for a poorly known baryon resonance, the one-star Δ(2200)7/2−\Delta(2200)7/2^-. This is the lowest-mass Δ∗\Delta^* resonance with spin-parity JP=7/2−J^P=7/2^-. Its mass is significantly higher than the mass of its parity partner Δ(1950)7/2+\Delta(1950)7/2^+ which is the lowest-mass Δ∗\Delta^* resonance with spin-parity JP=7/2+J^P=7/2^+. It has been suggested that chiral symmetry might be restored in the high-mass region of hadron excitations, and that these two resonances should be degenerate in mass. Our findings are in conflict with this prediction.Comment: 5 pages, 3 figures; Physics Letters B in pres

    Parameter Estimation and Quantitative Parametric Linkage Analysis with GENEHUNTER-QMOD

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    Objective: We present a parametric method for linkage analysis of quantitative phenotypes. The method provides a test for linkage as well as an estimate of different phenotype parameters. We have implemented our new method in the program GENEHUNTER-QMOD and evaluated its properties by performing simulations. Methods: The phenotype is modeled as a normally distributed variable, with a separate distribution for each genotype. Parameter estimates are obtained by maximizing the LOD score over the normal distribution parameters with a gradient-based optimization called PGRAD method. Results: The PGRAD method has lower power to detect linkage than the variance components analysis (VCA) in case of a normal distribution and small pedigrees. However, it outperforms the VCA and Haseman-Elston regression for extended pedigrees, nonrandomly ascertained data and non-normally distributed phenotypes. Here, the higher power even goes along with conservativeness, while the VCA has an inflated type I error. Parameter estimation tends to underestimate residual variances but performs better for expectation values of the phenotype distributions. Conclusion: With GENEHUNTER-QMOD, a powerful new tool is provided to explicitly model quantitative phenotypes in the context of linkage analysis. It is freely available at http://www.helmholtz-muenchen.de/genepi/downloads. Copyright (C) 2012 S. Karger AG, Base

    Auditing Cases That Made A Difference: Mckesson & Robbins

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    Many cases have impacted how today’s independent auditor does the job of expressing an opinion on financial statements.  Students taking auditing classes memorize the names and dates of the some of these cases, but rarely learn the facts of the cases or appreciate why the cases were so critical to advancing modern auditing standards.  McKesson & Robbins is one of the earliest of these cases.  Spanning more than a decade, two continents, two generations and at least four surnames, this case clearly shows students that fraud is not limited to today’s corporations and that there is, indeed, little that is new under the sun
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