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Biomedical subjects

S M Forbes

Publications and source records attributed to S M Forbes.

7 recordsLinked to original sources

The creation and early implementation of a high speed fiber optic network for a university health sciences center.

In late 1989 the University of Missouri Health Sciences Center began the process of creating an extensive fiber optic network throughout its facilities, with the intent to provide networked computer access to anyone in the Center desiring such access, regardless of geographic location or organizational affiliation. A committee representing all disciplines within the Center produced and, in conjunction with independent consultants, approved a comprehensive design for the network. Installation of network backbone components commenced in the second half of 1990 and was completed in early 1991. As the network entered its initial phases of operation, the first realities of this important new resource began to manifest themselves as enhanced functional capacity in the Health Sciences Center. This paper describes the development of the network, with emphasis on its design criteria, installation, early operation, and management. Also included are discussions on its organizational impact and its evolving significance as a medical community resource.

Academic Medical Centers

Diltiazem and exercise performance in patients with chronic atrial fibrillation.

To evaluate the influence of calcium entry blockade (diltiazem 60 mg qid) on exercise capacity in patients with chronic atrial fibrillation, nine men (mean age 65 years) with atrial fibrillation underwent maximal treadmill exercise on and off diltiazem therapy. Heart rate, blood pressure, and measured ventilatory parameters were assessed at a standard submaximal workload (3.0 mph/0% grade), the gas exchange anaerobic threshold (ATge), and maximal exercise. Significant reductions in heart rate at all stages of exercise were demonstrated: maximum heart rate decreased from 171 +/- 30 beats/min to 142 +/- 27 beats/min (17 percent, p less than .01) and submaximal exercise heart rate decreased from 123 +/- 22 beats/min to 96 +/- 16 beats/min (22 percent, p less than .01). However, there were no significant changes in blood pressure or gas exchange data, ie, oxygen uptake, minute ventilation, or respiratory exchange ratio at any of the exercise workloads. These data demonstrate that in patients with chronic atrial fibrillation, diltiazem controls the ventricular rate response throughout exercise without attenuating blood pressure or exercise capacity.

Aged

PEST reduces bias in forced choice psychophysics.

Observers performed several different detection tasks using both the PEST adaptive psychophysical procedure and a fixed-level (method of constant stimuli) psychophysical procedure. In two experiments, PEST runs targeted at P (C) = 0.80 were immediately followed by fixed-level detection runs presented at the difficulty level resulting from the PEST run. The fixed-level runs yielded P (C) about 0.75. During the fixed-level runs, the probability of a correct response was greater when the preceding response was correct than when it was wrong. Observers, even highly trained ones, perform in a nonstationary manner. The sequential dependency data can be used to determine a lower bound for the observer's "true" capability when performing optimally; this lower bound is close to the PEST target, and well above the forced choice P (C). The observer's "true" capability is the measure used by most theories of detection performance. A further experiment compared psychometric functions obtained from a set of PEST runs using different targets with those obtained from blocks of fixed-level trials at different levels. PEST results were more stable across observers, performance at all but the highest signal levels was better with PEST, and the PEST psychometric functions had shallower slopes. We hypothesize that PEST permits the observer to keep track of what he is trying to detect, whereas in the fixed-level method performance is disrupted by memory failure. Some recently suggested "more virulent" versions of PEST may be subject to biases similar to those of the fixed-level procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Auditory Perception