IMAGING OF LOW REDSHIFT QSOs WITH WFPC2

Observations with the PC2 CCD of the Hubble Space Telescope are described of two bright QSOs of redshift ~0.3. 1403+434 is IR-bright and radio-quiet, and 2201+315 is radio-loud with extended structure. Exposures were taken with the F702W and F555W filters. The images are deconvolved on their own and combined with 0.5 arcsec ground-based images. Both host galaxies have the form and luminosity of bright ellipticals, with nuclei of 1-2 times higher luminosity. 1403+434 is strongly interacting while 2201+315 may be in later stages of a merger, both with a smaller companion. Both host galaxies have compact knots and other small-scale peculiar features. Some general remarks are made based on the total program sample of 6 QSOs.Comment: 11 pages, Plain TeX, 3 figures available from [email protected] To appear in the Astronomical Journal

Intensities of backscatter Mössbauer spectra

The intensities of γ‐ray and x‐ray backscatter Mössbauer spectra of ^(57)Fe nuclei in different matrix materials were studied theoretically and experimentally. A previous analysis by J. J. Bara [Phys. Status Solidi A 58, 349 (1980] showed that negative peak intensities occur in backscatter γ‐ray spectra when the ^(57)Fe nuclei are in a matrix of light elements. We report a confirmation of this work and offer a simple explanation of the phenomenon. The present paper extends Bara’s analysis to the case of conversion x‐ray spectra; expressions for the intensity of conversion x‐ray spectra as a function of absorber thickness and absorber material parameters are presented. We show that negative peak intensities are expected in conversion x‐ray spectra when the ^(57)Fe nuclei are in a matrix of heavy elements

Properties of derivative expansion approximations to the renormalization group

Approximation only by derivative (or more generally momentum) expansions, combined with reparametrization invariance, turns the continuous renormalization group for quantum field theory into a set of partial differential equations which at fixed points become non-linear eigenvalue equations for the anomalous scaling dimension $\eta$. We review how these equations provide a powerful and robust means of discovering and approximating non-perturbative continuum limits. Gauge fields are briefly discussed. Particular emphasis is placed on the r\^ole of reparametrization invariance, and the convergence of the derivative expansion is addressed.Comment: (Minor touch ups of the lingo.) Invited talk at RG96, Dubna, Russia; 14 pages including 2 eps figures; uses LaTeX, epsf and sprocl.st

Development and evaluation of a prototype in-flight instrument flight rules (IFR) procedures trainer

An in-flight instrument flight rules (IFR) procedures trainer capable of providing simulated indications of instrument flight in a typical general aviation aircraft independent of ground based navigation aids was developed. The IFR navaid related instruments and circuits from an ATC 610J table top simulator were installed in a Cessna 172 aircraft and connected to its electrical power and pitot static systems. The benefits expected from this hybridization concept include increased safety by reducing the number of general aviation aircraft conducting IFR training flights in congested terminal areas, and reduced fuel use and instruction costs by lessening the need to fly to and from navaid equipped airports and by increased efficiency of the required in-flight training. Technical feasibility was demonstrated and the operational feasibility of the concept was evaluated. Results indicated that the in-flight simulator is an effective training device for teaching IFR procedural skills

Ranking the Risks: The 10 Pathogen-Food Combinations With the Greatest Burden on Public Health

Examines food-borne pathogens with the highest disease burdens and the top ten foods most commonly contaminated by them, such as salmonella in poultry, toxoplasma in pork, and listeria in deli meats. Makes policy recommendations for improving prevention

Charged Vacuum Bubble Stability

A type of scenario is considered where electrically charged vacuum bubbles, formed from degenerate or nearly degenerate vacuua separated by a thin domain wall, are cosmologically produced due to the breaking of a discrete symmetry, with the bubble charge arising from fermions residing within the domain wall. Stability issues associated with wall tension, fermion gas, and Coulombic effects for such configurations are examined. The stability of a bubble depends upon parameters such as the symmetry breaking scale and the fermion coupling. A dominance of either the Fermi gas or the Coulomb contribution may be realized under certain conditions, depending upon parameter values.Comment: 16 pages,revtex; accepted for publication in Phys.Rev.

Surface enhancement of oxygen exchange and diffusion in the ionic conductor La2Mo2O9

Isotopic surface oxygen exchange and its subsequent diffusion have been measured using secondary ion mass spectrometry in the fast ionic conductor La2Mo2O9. A silver coating was applied to the sample surface to enhance the surface exchange process for dry oxygen. Contrary to previous studies performed using a wet atmosphere, no grain boundary diffusion tail was observed under these optimized dry exchange conditions. The activation energy for oxygen diffusion was found to be 0.66(+/- 0.09) eV at high temperature (>570 degrees C), and 1.25(+/- 0.01)eV at low temperature (<570 degrees C). Time-of-Flight secondary ion mass spectrometry was employed to investigate the correlation between the silver coating and the O-18 concentration on the sample surface. A close correlation between the presence of silver and oxygen incorporation on the surface was observed. (C) 2010 Elsevier B.V. All rights reserved

Incorporating DNA Sequencing into Current Prenatal Screening Practice for Down's Syndrome

PMCID: PMC3604109This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Computer acquired performance data from a chemically vapor-deposited-rhenium, niobium planar diode

Performance data from a chemically vapor-deposited-rhenium, niobium thermionic converter are presented. The planar converter has a guard-ringed collector and a nominal fixed spacing of 0.25 mm (10 mils). The data were obtained by using a computerized acquisition system and are available on request to one of the authors on microfiche as individual and composite parametric current, voltage curves. The parameters are the temperatures of the emitter T sub E collector T sub C, and cesium reservoir T sub R. The composite plots have constant T sub E and varying T sub C or T sub R, or both. Current, voltage envelopes having constant T sub E with and without fixed T sub C appear in the present report. The diode was tested at increments between 1600 and 2000 K for the emitter Hohlraum, 800 to 1100 K for the collector, and 540 and 650 K for the reservoir. A total of 312 current, voltage curves were obtained in the present performance evaluation. Current, voltage envelopes from three rhenium emitter converters evaluated in the present program are also given. The data are compared at commom emitter Hohlraum temperatures

An experimental and theoretical investigation of deposition patterns from an agricultural airplane

A flight test program has been conducted with a representative agricultural airplane to provide data for validating a computer program model which predicts aerially applied particle deposition. Test procedures and the data from this test are presented and discussed. The computer program features are summarized, and comparisons of predicted and measured particle deposition are presented. Applications of the computer program for spray pattern improvement are illustrated