6,016 research outputs found

    The Non-Classical Boltzmann Equation, and Diffusion-Based Approximations to the Boltzmann Equation

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    We show that several diffusion-based approximations (classical diffusion or SP1, SP2, SP3) to the linear Boltzmann equation can (for an infinite, homogeneous medium) be represented exactly by a non-classical transport equation. As a consequence, we indicate a method to solve diffusion-based approximations to the Boltzmann equation via Monte Carlo, with only statistical errors - no truncation errors.Comment: 16 pages, 3 figure

    An Empirical Study of Public Accountants\u27 Risk-Taking Propensities

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    J. W. Martin is an Assistant Professor of Accounting at Virginia Polytechnic Institute and E. R. Mansfield is an Associate Professor of Statistics at the University of Alabama

    The Ursinus Weekly, December 1, 1905

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    Review of the football season • Death of the Reverend Joseph H. Hendricks, D. D. • Football captain for 1906 • Society notes • Pick ups • Basketballhttps://digitalcommons.ursinus.edu/weekly/2959/thumbnail.jp

    High-resolution broadband spectroscopy using externally dispersed interferometry at the Hale telescope: part 2, photon noise theory

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    High-resolution broadband spectroscopy at near-infrared (NIR) wavelengths (950 to 2450 nm) has been performed using externally dispersed interferometry (EDI) at the Hale telescope at Mt. Palomar, with the TEDI interferometer mounted within the central hole of the 200-in. primary mirror in series with the comounted TripleSpec NIR echelle spectrograph. These are the first multidelay EDI demonstrations on starlight. We demonstrated very high (10×) resolution boost and dramatic (20× or more) robustness to point spread function wavelength drifts in the native spectrograph. Data analysis, results, and instrument noise are described in a companion paper (part 1). This part 2 describes theoretical photon limited and readout noise limited behaviors, using simulated spectra and instrument model with noise added at the detector. We show that a single interferometer delay can be used to reduce the high frequency noise at the original resolution (1× boost case), and that except for delays much smaller than the native response peak half width, the fringing and nonfringing noises act uncorrelated and add in quadrature. This is due to the frequency shifting of the noise due to the heterodyning effect. We find a sum rule for the noise variance for multiple delays. The multiple delay EDI using a Gaussian distribution of exposure times has noise-to-signal ratio for photon-limited noise similar to a classical spectrograph with reduced slitwidth and reduced flux, proportional to the square root of resolution boost achieved, but without the focal spot limitation and pixel spacing Nyquist limitations. At low boost (∼1×) EDI has ∼1.4× smaller noise than conventional, and at >10× boost, EDI has ∼1.4× larger noise than conventional. Readout noise is minimized by the use of three or four steps instead of 10 of TEDI. Net noise grows as step phases change from symmetrical arrangement with wavenumber across the band. For three (or four) steps, we calculate a multiplicative bandwidth of 1.8:1 (2.3:1), sufficient to handle the visible band (400 to 700 nm, 1.8:1) and most of TripleSpec (2.6:1)

    Laboratory and field partial discharge measurement in HVDC power cables

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    A range of experimental and field measurements of partial discharge (PD) activity under high voltage direct current (HVDC) conditions have been conducted with the goal of developing effective monitoring techniques for PD in HVDC cables and ancillary equipment, particularly in offshore renewable energy HVDC grid installations. Laboratory measurements on insulation test objects and cross linked polyethylene (XLPE) cable samples have been conducted to better understand the characteristics of PD activity under direct current (DC) stress in comparison with AC. In addition, long-term PD measurements carried out at both an HVDC cable aging laboratory and an in-service HVDC interconnector circuit are presented together with a description of the monitoring system architecture

    "Chest Pain Typicality" in Suspected Acute Coronary Syndromes and the Impact of Clinical Experience

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    BACKGROUND: Physicians rely upon chest pain history to make management decisions in patients with suspected acute coronary syndromes, particularly where the diagnosis is not immediately apparent through ECG and troponin testing. OBJECTIVE: To establish the discriminatory value of 'typicality of chest pain' and the effect of clinician experience, for the prediction of acute myocardial infarction and presence of significant coronary artery disease. METHODS: Prospective single-center observational study undertaken in a U.K. General Hospital emergency department. We recruited consecutive adults with chest pain and a non-diagnostic ECG, for whom the treating physician determined delayed troponin testing was necessary. Using their own clinical judgment, physicians recorded whether the chest pain described was typical or atypical for acute coronary syndrome. Physicians were defined as "experienced" or "novice" according to postgraduate experience. Acute myocardial infarction was adjudicated using a high-sensitivity troponin (hs-cTn) assay, while coronary artery disease was adjudicated angiographically. RESULTS: Overall, 912 patients had typicality of chest pain assessed, of whom 114/912 (12.5%) had an acute myocardial infarction and 157/912 (17.2%) underwent angiography. In patients undergoing angiography, 90/157 (57.3%) had hs-cTn elevation, of whom 60 (66.7%) had significant coronary artery disease. 67/157 (42.7%) patients had angiography without hs-cTn elevation, of these 31 (46.2%) had significant coronary artery disease. For the diagnosis of acute myocardial infarction, chest pain typicality had an area under the curve (AUC) of 0.54 (95%CI 0.49-0.60). For the prediction of significant coronary artery disease with hs-cTn elevation AUC: 0.54 (0.40-0.67), and without hs-cTn elevation AUC: 0.45 (0.31-0.59). When assessed by experienced physicians, specificity for the diagnosis of acute myocardial infarction was higher at 65.8% (63.1%-68.7%) vs. 55.4% (53.9%-56.8%) for novices. CONCLUSIONS: Subjective interpretation of 'typicality of chest pain' is of limited discriminatory value in the assessment of suspected acute coronary syndromes, in the context of a non-diagnostic ECG. Greater clinical experience improves accuracy as a rule-in tool but does not improve overall discriminatory ability

    Nurses\u27 Alumnae Association Bulletin - Volume 6 Number 10

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    Financial Report Calendar of Events Attention, Class of 1945! Miss Shafer Retires Review of the Alumnae Association Meetings Institutional Staff Nurses\u27 Section Report of Staff Activites - 1948-1949 The Staff Stockings! Stockings! Stockings! Pop-Up Toaster It\u27s Not Too Soon Any White Elephants? Private Duty Section The Jefferson Hospital Private Duty Nurses\u27 Register Report for Barton Memorial Hospital Progress of the Orthopedic Department Just Under the Date Line Pediatrics at Jefferson Controlled Respiration in Anesthesia Anesthesia Progress Physical Advances at Jefferson During the Past Year The White Haven Division The Clara Melville Scholarship Fund The Relief Fund The Busy Year for the Nurses\u27 Home Committee of the Women\u27s Board The Gray Ladies Memories Lost Miscellaneous Items Medical College News Marriages Births Deaths Condolences Prizes District No. 1 Dues Help! Help! Help! Jap Prison School Spurs Nurse to Win University Degree Twenty Ways to Kill an Organization The Bulletin Committee Attention, Alumnae New Addresse
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