IRDS prototyping with applications to the representation of EA/RA models

The requirements and system overview for the Information Resources Dictionary System (IRDS) are described. A formal design specification for a scaled down IRDS implementation compatible with the proposed FIPS IRDS standard is contained. The major design objectives for this IRDS will include a menu driven user interface, implementation of basic IRDS operations, and PC compatibility. The IRDS was implemented using Smalltalk/5 object oriented programming system and an ATT 6300 personal computer running under MS-DOS 3.1. The difficulties encountered in using Smalltalk are discussed

The Health Care Safety Net and Crowd-Out of Private Health Insurance

There is an extensive literature on the extent to which public health insurance coverage through Medicaid induces less private health insurance coverage. However, little is known about the effect of other components of the health care safety net in crowding out private coverage. We examine the effect of Medicaid and uncompensated care provided by clinics and hospitals on insurance coverage. We construct a long panel of metropolitan area and state-level data on hospital uncompensated care and free and reduced price care offered by Federally Qualified Health Centers. We match this information to individual level data on coverage from the Current Population Survey for two distinct groups: children aged 14 and under and single, childless adults aged 18 to 64. Our results provide mixed evidence on the extent of crowd-out. Hospital uncompensated care does not appear to crowd-out health insurance coverage and health center uncompensated care appears to crowd-out private coverage for adults and, in some specifications, children.

Some Revised Observational Constraints on the Formation and Evolution of the Galactic Disk

A set of 76 open clusters with abundances based upon DDO photometry and/or moderate dispersion spectroscopy has been transformed to a common [Fe/H] scale and used to study the local structure and evolution of the galactic disk. The metallicity distribution of clusters with R_GC is best described by two distinct zones. Between R_GC = 6.5 and 10 kpc, the distribution has a mean [Fe/H] = 0.0 and a dispersion of 0.1 dex; there is only weak evidence for a shallow abundance gradient over this distance range. Beyond R_GC = 10 kpc, the metallicity distribution has a dispersion between 0.10 and 0.15 dex, but with a mean [Fe/H] = -0.3, implying a sharp discontinuity at R_GC = 10 kpc. After correcting for the discontinuity, no evidence is found for a gradient perpendicular to the plane. Adopting the clusters interior to 10 kpc as a representative sample of the galactic disk over the last 7 Gyr, the cluster metallicity range is found to be about half that of the field stars. When coupled with the discontinuity in the galactocentric gradient, the discrepancy in the metallicity distribution is interpreted as an indication of significant diffusion of field stars into the solar neighborhood from beyond 10 kpc. These results imply that the sun is NOT atypical of the stars formed in the solar circle 4.6 Gyr ago. It is suggested that the discontinuity reflects the edge of the initial galactic disk as defined by the disk globular cluster system and the so-called thick disk; the initial offset in [Fe/H] created by the differences in the chemical history on either side of the discontinuity has carried through to the current stage of galactic evolution. If correct, diffusion coupled with the absence of an abundance gradient could make the separation of field stars on the basis of galactocentric origin difficult.Comment: 41 pages, 9 figure files, LaTex. Appendix section and tables (tex or postscript) available at http://kubarb.phsx.ukans.edu/ ~twarog/ Submitted to Astronomical Journal July 199

The use of the BANG-3 polymer gel to quantify the three-dimensional dose distribution of IMRT

The sophistication of radiation therapy delivery techniques at Mary Bird Perkins Cancer Center (MBPCC) creates the need for an advanced dosimetric system that can quantify and verify the dose distributions in three-dimensions. Current dosimetric systems perform this dose analysis in only one or two dimensions. This paper evaluates the application of BANG-3™ polymer gel dosimetry to quantify the 3-D dose distribution of Intensity-Modulated Radiation Therapy (IMRT) using a step and shoot approach. The gel was irradiated by 10 MV photons at a dose rate of 400 MU/min. Relaxation rate maps were computed from proton density and T2-weighted magnetic resonance images acquired with a GE Horizon 1.5T scanner; scans were performed 5 days and 2 months post-irradiation. The dose distribution within the gel was compared to the dose distribution calculated by the Pinnacle3 planning system. Three techniques were used for analysis: image subtraction, dose-volume analysis and contour analysis. Also, a dose correction factor was used to attempt to correct for excess dose delivered to the gel as the gels were erroneously placed in the treatment room two days prior to irradiation. Corrected 5-day post-irradiation dose maps show reasonable agreement with the Pinnacle3 plan. The absolute measurement error was +/-50 cGy; however, the relative errors were large compared to the total dose of 2 Gy delivered to the gel. Delivering a larger total dose should reduce the relative error to a reasonable magnitude. Exposure to light and other environmental factors caused substantial additional polymerization with time. The results of this project indicate that polymer gel dosimetry could be a useful routine 3D dosimetric technique at MBPCC. However, utilizing a commercial scanning service may simplify use of the gels

Human red cell NADP-dependent xylitol dehydrogenase: kinetic and genetic studies

A Thesis submitted to the Faculty of Medicine, University of the Witwatersrand, Johannesburg, for the Degree of Doctor of Philosophy.A deficiency of the enzyme NADP dependent xylitol dehydrogenase (L-xylulose reductase) has previously been found to be the cause of chronic essential pentosuria. Essential pentosuria is a recessively inherited condition which is marked by the continual excretion of relatively large amounts of the enzymes substrate, L-xylulose. The major objective of the study described was to find a simple method for the identification of individuals who are heterozygous for the "pentosuria" and normal alleles. The pentosuria allele could then be used as a gene marker in linkage studies aimed at mapping the L-xylulose reductase locus. A L-xylulose reductase assay suitable for the identification of carriers of essential pentosuria was developed and tested on members of a South African Lebanese family in which the inheritance of pentosuria had previously been suggested to be dominant. It was found that family members could, on the basis of their L-xylulose reductase activities, be classified as either normal, heterozygous or homozygous for the pentosuria allele. Measurements of serum L-xylulose concentrations revealed that pentosuria is, contrary to the previous report, . recessively inherited in this family. A sample of the local Ashkenazi Jewish population was screened for pentosuria carriers. Six out of the 237 individuals screened were found (on the basis of their L-xylulose reductase activities and from the results of a loading test), to carry the pentosuria allele. The frequency of the pentosuria allele in this population was estimated from the apparent heterozygote frequency to be 0.0127. Linkage analyses were carried out on the families of the identified heterozygotes and on members of the Lebanese family mentioned above. No evidence of tight linkage was found between the pentosuria allele's locus and those coding for various red cell antigens, red cell enzymes and serum proteins. Kinetic, chromatographic and electrophoretic studies revealed that the red cells of normal individuals contain two distinct L-xylulose reductases, a minor and a major isozyme. Pentosurics lack the major isozyme but appear to have approximately normal amounts of the minor isozyme. The minor isozyme is e1ectrophoretica 1 1 y distinct from the major isozyme, has markedly higher Michael is constants for the substrates L-xylulose and xylitol and shows a lower pH optimum when catalysing the oxidation of xylitol. Electrophoresis also revealed that liver tissue contains two L-xylulose reductases which occur in similar proportions to those of red cells but which migrate at slightly different rates.WHSLYP201

The Unevolved Main Sequence of Nearby Field Stars and the Open Cluster Distance Scale

The slope and zero-point of the unevolved main sequence as a function of metallicity are investigated using a homogeneous catalog of nearby field stars with absolute magnitudes defined with revised Hipparcos parallaxes, Tycho-2 photometry, and precise metallicities from high-dispersion spectroscopy. (B-V)-temperature relations are derived from 1746 stars between [Fe/H] = -0.5 and +0.6 and 372 stars within 0.05 dex of solar abundance; for T_e = 5770 K, the solar color is B-V= 0.652 +/- 0.002 (s.e.m.). From over 500 cool dwarfs between [Fe/H] = -0.5 and +0.5, Delta(B-V)/Delta[Fe/H] at fixed M_V = 0.213 +/- 0.005, with a very weak dependence upon the adopted main sequence slope with B-V at a given [Fe/H]. At Hyades metallicity this translates into Delta M_V/Delta[Fe/H] at fixed B-V = 0.98 +/- 0.02, midway between the range of values empirically derived from smaller and/or less homogeneous samples and model isochrones. From field stars of similar metallicity, the Hyades ([Fe/H] = +0.13) with no reddening has (m-M)_0 = 3.33 +/- 0.02 and M67, with E(B-V) = 0.041, A_V = 3.1E(B-V), and [Fe/H] = 0.00, has (m-M)_0 = 9.71 +/- 0.02 (s.e.m), where the errors quoted refer to internal errors alone. At the extreme end of the age and metallicity scale, with E(B-V) = 0.125 +/- 0.025 and [Fe/H] = +0.39 +/- 0.06, comparison of the fiducial relation for NGC 6791 to 19 field stars with (B-V) above 0.90 and [Fe/H] = +0.25 or higher, adjusted to the metallicity of NGC 6791, leads to (m-M)_0 = 13.07 +/- 0.09, internal and systematic errors included.Comment: 32 pages, 8 eps figures, latex; accepted for PAS

Using World-Wide-Web technology for pathology education

In this article, we describe the development of computer-based learning programs for pathology students at Jefferson Medical College. These programs are authored using HTML (HyperText Markup Language), and are available to students on campus and via the internet. Our computer-based learning resources include scheduling information, course goals and objectives, glossary of key words, self-assessment programs and image-based case studies. These educational programs are popular with the students. We recommend the use of World Wide Web technology to improve teaching and learning in pathology education

Benchmarking of three parallelized implementations of LS-Dyna on a HPC server cluster

This paper discusses the benchmarking of three parallelized implementations of the popular LS-Dyna® finite element code (Livermore Software Technology Corp.) on the STePS2 high performance computing (HPC) server cluster. SMP, MPP and SMP-MPP hybrid implementations of LS-Dyna® are benchmarked over various numbers of nodes, cpus and cpu cores. The STePS2 HPC cluster consists of a dual-cpu head node and 16 homogeneous dual-cpu compute nodes. All nodes are interconnected via an Infiniband® network fabric. All cpus are quad-core Intel Xeon 64-bit and the operating system(s) is the ROCKS cluster management software implemented through Redhat Enterprise Linux 5 (x86_64). SMP, MPP and MPP-SMP hybrid implementations of LS-Dyna were compiled for use with the HPMPI message passing interface