The College of American Pathologists, 1946-1996. Quality Assurance Service

Since its creation in 1970, the College of American Pathologists Quality Assurance Service Committee has provided important and highly respected interlaboratory programs for daily quality control. In 1988, this committee extended its domain by announcing Q-Probes, a unique benchmarking program for laboratory quality assurance. Because of the success and rapid growth of this program during the next 2 years, the Quality Assurance Service Committee expanded into two committees, namely, QAS-QC and QAS-QA, with expertise concentrated, respectively, in quality control and quality assurance. These committees have compiled a history of significant scientific and educational contributions to members, the international laboratory community, other physicians, and patients. New directions for both committees are now underway so that their contributions can continue in the rapidly changing field of pathology and laboratory medicine.     

Transmit selection in spatial multiplexing systems

In this letter we solve the transmit antenna selection problem for a zero forcing spatial multiplexing system with knowledge of the channel statistics at the transmitter. We show through Wishart matrix analysis that the signal-to-noise ratio on the kth stream is a weighted Chi-squared variable with the weight equal to-the kth diagonal entry of the inverted transmit correlation matrix. We use this result to develop selection algorithms for two cases-maximizing ergodic capacity and minimizing the average probability of error. Monte Carlo simulations illustrate potential performance improvements.     

PARTICLE DISPERSION BY LARGE SCALE VORTEX STRUCTURES

This paper demonstrates the effect of large scale structures found in free shear layers on the dispersion of solid particles. Numerical simulation of a free shear layer using a psuedo-spectral code were carried out with the addition of discrete particles. It was shown that the dispersion of particles is strongly dependent on the Stokes number with the possibility of particle dispersions being greater than the fluid dispersion at certain values of the Stokes number. These trends compare qualitatively with flow visualization of a free shear flow with solid particles.     

Althesin infusion for cardiac catheterisation

A trial of a continuous intravenous infusion of Althesin is described for sedation during cardiac catheterisation, both for children and adults. The conditions produced for the procedure were very satisfactory. The advantages and problems of its use are discussed. The technique justifies further trials.     

Seasonal variation in the composition of the drift below a peaking hydroelectric project

We used 0.5 m diameter nets to sample the drift downstream from a peaking hydroelectric project on the Caney Fork River, Tennessee. The relative contribution of the terrestrial, lentic, and lotic environments to stream drift varied seasonally. Stream benthos (primarily Chironomidae and Lirceus fontinalis) occurred in the drift throughout the year; however, their relative importance varied seasonally. Daphnia sp. from the reservoir also occurred in the drift year round with the highest densities in fall and spring when they were the predominant species in the drift. In summer, terrestrial insects apparently utilized exposed portions of the river bed during periods of no power generation. In June as the river stage increased following initiation of generation, adult terrestrial insects became a major component of the drift. Threadfin shad (Dorosoma petenense) dominated the biomass in the drift during December. Although the importance of stream benthos to fish populations is generally recognized, the contribution of the terrestrial and upstream reservoir environments to the forage base in the tailwater may also be important and should be considered in developing management strategies for tailwater fisheries.