1,277 research outputs found

    <effects of low energy proton irradiation on solar cells< monthly progress report, jan. 1965

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    Low energy proton irradiated solar cells using sun simulato

    High Redshift Standard Candles: Predicted Cosmological Constraints

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    We investigate whether future measurements of high redshift standard candles (HzSCs) will be a powerful probe of dark energy, when compared to other types of planned dark energy measurements. Active galactic nuclei and gamma ray bursts have both been proposed as potential HzSC candidates. Due to their high luminosity, they can be used to probe unexplored regions in the expansion history of the universe. Information from these regions can help constrain the properties of dark energy, and in particular, whether it varies over time. We consider both linear and piecewise parameterizations of the dark energy equation of state, w(z)w(z), and assess the optimal redshift distribution a high-redshift standard-candle survey could take to constrain these models. The more general the form of the dark energy equation of state w(z)w(z) being tested, the more useful high-redshift standard candles become. For a linear parameterization of w(z)w(z), HzSCs give only small improvements over planned supernova and baryon acoustic oscillation measurements; a wide redshift range with many low redshift points is optimal to constrain this linear model. However to constrain a general, and thus potentially more informative, form of w(z)w(z), having many HzSCs can significantly improve limits on the nature of dark energy.Comment: Accepted MNRAS, 27 Pages, 15 figures, matches published versio

    Cross-comparison of MRCGP & MRCP(UK) in a database linkage study of 2,284 candidates taking both examinations: assessment of validity and differential performance by ethnicity.

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    MRCGP and MRCP(UK) are the main entry qualifications for UK doctors entering general [family] practice or hospital [internal] medicine. The performance of MRCP(UK) candidates who subsequently take MRCGP allows validation of each assessment. In the UK, underperformance of ethnic minority doctors taking MRCGP has had a high political profile, with a Judicial Review in the High Court in April 2014 for alleged racial discrimination. Although the legal challenge was dismissed, substantial performance differences between white and BME (Black and Minority Ethnic) doctors undoubtedly exist. Understanding ethnic differences can be helped by comparing the performance of doctors who take both MRCGP and MRCP(UK)

    Optimization of Lean and Agile Supply Chain Management Practices in the Aviation Industry

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    Organizations that provide products and/or services must be able to execute fast, adaptive supply and (fluctuating) demand practices. From producers to consumers, and every stakeholder involved throughout the supply chain network processes, a collaborative relationship promotes sharing information that is beneficial to all. This long-term relationship then flourishes and in return stimulates the growth, health, and stability of the supply chain. Understanding the organizational processes and requirements is a complex endeavor. However, with technological advances and with the right type of data collected, it is possible to optimize entire supply chain networks. This research study, seeks to provide an insight into theoretical supply and demand optimization methods and help identify optimal selection of variables and types of data needed to analyze lean and agile methodology approaches in order to show how to blend a lean, continuous, flow approach, with agile, flexible, fluctuations in customer demands, for consistent tactical and operational outcomes across supply chain networks in the aviation industry

    Rapid readout of a register of qubits using open loop quantum control

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    Measurements are a primitive for characterizing quantum systems. Reducing the time taken to perform a measurement may be beneficial in many areas of quantum information processing. We show that permuting the eigenvalues of the state matrix in the logical basis, using open loop control, provides a O(n)O(n) reduction in the measurement time, where nn is the number of qubits in the register. This reduction is of the same order as the (previously introduced) locally optimal feedback protocol. The advantage of the open loop protocol is that it is far less difficult experimentally. Because the control commutes with the measured observable at all times, our rapid measurement protocol could be used for characterizing a quantum system, by state or process tomography, or to implement measurement-based quantum error correction

    The Importance of Broad Emission-Line Widths in Single Epoch Black Hole Mass Estimates

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    Estimates of the mass of super-massive black holes (BHs) in distant active galactic nuclei (AGNs) can be obtained efficiently only through single-epoch spectra, using a combination of their broad emission-line widths and continuum luminosities. Yet the reliability and accuracy of the method, and the resulting mass estimates, M_BH, remain uncertain. A recent study by Croom using a sample of SDSS, 2QZ and 2SLAQ quasars suggests that line widths contribute little information about the BH mass in these single-epoch estimates and can be replaced by a constant value without significant loss of accuracy. In this Letter, we use a sample of nearby reverberation-mapped AGNs to show that this conclusion is not universally applicable. We use the bulge luminosity (L_Bulge) of these local objects to test how well the known M_BH - L_Bulge correlation is recovered when using randomly assigned line widths instead of the measured ones to estimate M_BH. We find that line widths provide significant information about M_BH, and that for this sample, the line width information is just as significant as that provided by the continuum luminosities. We discuss the effects of observational biases upon the analysis of Croom and suggest that the results can probably be explained as a bias of flux-limited, shallow quasar samples.Comment: 10 text pages + 4 Figures + 1 Table. Accepted for publication in ApJ Letter

    Conceptualizing the Academic Event: Blending Theory, Practice and Public Relations

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    This paper describes the conceptualization, design and execution of a unique academic event that serves several audiences. The business theory planning, aspects of public relations, and meetings as a communication medium is used describe the event. Also addressed is the evolution and design of this academic event that provides the structure for industry to industry; industry to student; student to industry; university to industry; industry to university; student to potential employer and employer to university interaction

    Reverberation Mapping Results from MDM Observatory

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    We present results from a multi-month reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from around the world. We measure broad line region (BLR) radii and black hole masses for six objects. A velocity-resolved analysis of the H_beta response shows the presence of diverse kinematic signatures in the BLR.Comment: To appear in the Proceedings of the IAU Symposium No. 267: Co-Evolution of Central Black Holes and Galaxies, Rio de Janeiro, 200
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