49,647 research outputs found

    Computer program for calculation of complex chemical equilibrium compositions

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    Computer program is described for numerical solution of chemical equilibria in complex systems by using nonlinear algebraic equations. Free-energy minimization technique is used

    The Effect of Walkthrough Observations on Teacher Perspectives in Christian Schools

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    This study investigated the effects on teacher perceptions of frequent, brief classroom observations in Christian schools. Teachers (N=111) responded to 13 belief and value statements prior to and after the term during which administrators conducted weekly, brief, unannounced observations in their classes. Teachers reported significant positive change regarding (a) analyzing reasons for selecting methods to assess learning, (b) being encouraged after class observations, and (c) being encouraged after receiving feedback related to the observations

    A Conversation with Monroe Sirken

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    Born January 11, 1921 in New York City, Monroe Sirken grew up in a suburb of Pasadena, California. He earned B.A. and M.A. degrees in sociology at UCLA in 1946 and 1947, and a Ph.D. in 1950 in sociology with a minor in mathematics at the University of Washington in 1950 where Professor Z. W. Birnbaum was his mentor and thesis advisor. As a Post-Doctoral Fellow of the Social Science Research Council, Monroe spent 1950--1951 at the Statistics Laboratory, University of California at Berkeley and the Office of the Assistant Director for Research, U.S. Bureau of the Census in Suitland, Maryland. Monroe visited the Census Bureau at a time of great change in the use of sampling and survey methods, and decided to remain. He began his government career there in 1951 as a mathematical statistician, and moved to the National Office of Vital Statistics (NOVS) in 1953 where he was an actuarial mathematician and a mathematical statistician. He has held a variety of research and administrative positions at the National Center for Health Statistics (NCHS) and he was the Associate Director, Research and Methodology and the Director, Office of Research and Methodology until 1996 when he became a senior research scientist, the title he currently holds. Aside from administrative responsibilities, Monroe's major professional interests have been conducting and fostering survey and statistical research responsive to the needs of federal statistics. His interest in the design of rare and sensitive population surveys led to the development of network sampling which improves precision by linking multiple selection units to the same observation units. His interest in fostering research on the cognitive aspects of survey methods led to the establishment of permanent questionnaire design research laboratories, first at NCHS and later at other federal statistical agencies here and abroad.Comment: Published in at http://dx.doi.org/10.1214/07-STS245 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Computer program for calculation of ideal gas thermodynamic data

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    Computer program calculates ideal gas thermodynamic properties for any species for which molecular constant data is available. Partial functions and derivatives from formulas based on statistical mechanics are provided by the program which is written in FORTRAN 4 and MAP

    Molar mass and solution conformation of branched alpha(1 - 4), alpha(1 - 6) Glucans. Part I: Glycogens in water

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    Solution molar masses and conformations of glycogens from different sources (rabbit, oyster, mussel and bovine) were analysed using sedimentation velocity in the analytical ultracentrifuge, size-exclusion chromatography coupled to multi-angle laser light scattering (SEC-MALLS), size-exclusion chromatography coupled to a differential pressure viscometer and dynamic light scattering. Rabbit, oyster and mussel glycogens consisted of one population of high molar mass (weight averages ranging from 4.6 x 106 to 1.1 x 107 g/mol) as demonstrated by sedimentation velocity and SEC-MALLS, whereas bovine glycogen had a bimodal distribution of significantly lower molar mass (1.0 x 105 and 4.5 x 105 g/mol). The spherical structure of all glycogen molecules was demonstrated in the slopes of the Mark-Houwink-Kuhn-Sakurada-type power-law relations for sedimentation coefficient (s20,wo), intrinsic viscosity ([η]), radius of gyration (rg,z) and radius of hydration (rH,z), respectively, and was further supported by the � (=rg,z/rH,z) function, the fractal dimension and the Perrin function. The degree of branching was estimated to be ∼10% from the shrinking factors, g′ (=[η]branched/[η]linear) and also h (=(f/fo)branched/(f/fo)linear), respectively, where (f/fo) is the translational frictional ratio, consistent with expectation. © 2007 Elsevier Ltd. All rights reserved

    Magnetorotational-type instability in Couette-Taylor flow of a viscoelastic polymer liquid

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    We describe an instability of viscoelastic Couette-Taylor flow that is directly analogous to the magnetorotational instability (MRI) in astrophysical magnetohydrodynamics, with polymer molecules playing the role of magnetic field lines. By determining the conditions required for the onset of instability and the properties of the preferred modes, we distinguish it from the centrifugal and elastic instabilities studied previously. Experimental demonstration and investigation should be much easier for the viscoelastic instability than for the MRI in a liquid metal. The analogy holds with the case of a predominantly toroidal magnetic field such as is expected in an accretion disk and it may be possible to access a turbulent regime in which many modes are unstable.Comment: 4 pages, 4 figures, to be published in Physical Review Letter

    Computer Program for Calculation of Complex Chemical Equilibrium Compositions, Rocket Performance, Incident and Reflected Shocks, and Chapman-Jouguet Detonations. Interim Revision, March 1976

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    A detailed description of the equations and computer program for computations involving chemical equilibria in complex systems is given. A free-energy minimization technique is used. The program permits calculations such as (1) chemical equilibrium for assigned thermodynamic states (T,P), (H,P), (S,P), (T,V), (U,V), or (S,V), (2) theoretical rocket performance for both equilibrium and frozen compositions during expansion, (3) incident and reflected shock properties, and (4) Chapman-Jouguet detonation properties. The program considers condensed species as well as gaseous species

    Spectroscopic characterization and detection of Ethyl Mercaptan in Orion

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    New laboratory data of ethyl mercaptan, CH3_{3}CH2_{2}SH, in the millimeter and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of gauchegauche-CH3_3CH2_2SH towards Orion KL. 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz support this identification. A detection of methyl mercaptan, CH3_{3}SH, in the spectral survey of Orion KL is reported as well. Our column density results indicate that methyl mercaptan is \simeq 5 times more abundant than ethyl mercaptan in the hot core of Orion KL.Comment: Accepted for publication in ApJL (30 January 2014)/ submitted (8 January 2014

    Orthotopic liver transplantation for alcoholic cirrhosis.

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    Fifteen patients with Laennec's cirrhosis underwent orthotopic liver transplantation between 1963 and the end of 1979. The first eight patients died perioperatively or within two months, but four of the next seven patients had long survival; three are still alive after 11 to 14 years. After the introduction of cyclosporine therapy, 41 more patients with alcoholic cirrhosis were treated with liver transplantation from 1980 to June 1987. The one-year survival is 73.2%, and, after one to three years, 28 (68%) of the recipients are living. Of the 35 patients in the combined old and new series who lived for six months or longer, only two returned to alcohol abuse. Social and vocational rehabilitation has been the rule in these recipients who were selected primarily because of urgency of need, because they or their families insisted on treatment, and because they and their families thereby committed themselves to long-standing programs of alcoholism care

    On two 10th order mock theta identities

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    We give short proofs of conjectural identities due to Gordon and McIntosh involving two 10th order mock theta functions.Comment: 5 pages, to appear in the Ramanujan Journa
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