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Biomedical subjects

M C Dunn

Publications and source records attributed to M C Dunn.

5 recordsLinked to original sources
PubMed2000

Behavioural implications of alarm mistrust as a function of task workload.

The research was conducted to investigate the effect of increasing primary task and alarm workload on alarm mistrust as reflected by alarm and primary task performances. A total of 126 undergraduate students performed a complex psychomotor task battery three times, with the number of concurrent tasks increasing each time. During their performance, the students were required to react to an alarm system (including visual and auditory components) of questionable reliability. Depending on the group to which participants were assigned, the alarm presentation rate constituted a low-, medium- or high-workload condition. Alarm response data (times, frequencies, accuracies) and primary task data (tracking error) were analyzed to assess performance differences as a function of primary and secondary task workload levels. Results generally supported the hypotheses: increasing primary task and alarm task workload degraded alarm response performance. Also, response frequencies supported earlier research suggesting that participants 'probability match' their response rates to alarm system reliability. The results are discussed with regard to the cry-wolf effect, attention theory and alarm system design.

Analysis of Variance↗
PubMed1988

Simultaneous histochemical determination of three fiber types in single sections of ovine, bovine and porcine skeletal muscle.

Classification of muscle fiber types involves tedious comparisons of serial muscle tissue sections. Procedures that would incorporate pertinent histochemical properties into one simplified assay for the successful differentiation and determination of fiber types were evaluated using muscle samples from three different species (ovine, bovine and porcine). For ovine and porcine muscle tissue, the best staining procedure involved initial preincubation of the tissue section at 4.35 (for ovine) and 4.30 (for porcine) followed by incubating for succinate dehydrogenase (SDH) activity, then staining for myofibrillar adenosine triphosphatase (ATPase) activity after an acid preincubation and, finally, counterstaining with hematoxylin. For bovine muscle tissue, the procedure involves first incubating for SDH activity, after which the section is incubated at pH 4.15 and then stained for myofibrillar ATPase activity after an acid preincubation, with a concluding counterstaining using hematoxylin. These procedures permit successful differentiation and identification of three fiber types (beta R, alpha R and alpha W) from a single section of muscle tissue with approximately a 65% saving in time and materials. The results of histochemically typing muscle fibers in a single tissue section stained with these techniques were similar to those obtained with the traditional methods comparing serial sections.

Animals↗
PubMed1975

A prospective search for congenital dermal abnormalities of the craniospinal axis.

Nineteen-hundred and ninety-seven consecutive term newborn infants were examined for cutaneous abnormalities of the craniospinal axis. Fifty-eight of the neonates (3%) had one or more abnormalities. The major findings included 28 (1.4%) deep dimples; 23 (1.2%) presumed sinuses; six (0.3%) skin tags,and one nodular mass. Fifty children were seen in follow-up at 4 to 12 months; in 40 infants the initial major finding persisted unchanged. Surgery has been performed on five children. One dermal sinus was found to terminate at the dura, three sinuses terminated at the coccyx, and a skin tag was associated with a fibrous band that extended to the coccyx. The management of congenital dermal sinuses is discussed.

California↗