Biomedical subjects
Publications and source records attributed to L Buck.
Twenty-four male student volunteers were exposed to 50 ppm of nitrous oxide or air in an exposure chamber for 4 h in two experimental sessions. The subjects completed a battery of psychomotor tests during the final 40 min of the exposure sessions. Nitrous oxide, at this low concentration, did not produce any statistically significant changes in performance.
In a pursuit-tracking task consisting of 100 positioning movements between targets at 5 fixed positions, target location (proximity to the boundary of the task) varied independently of movement amplitude. Eighty-seven subjects performed 12 trials of the task, with target width (at 3 levels) as a between-subject variable. A microprocessor system detected the location of the end-point of each primary movement. Movement accuracy (measured as end-point dispersion not constant error) varied with target location but not movement amplitude, while movement time varied with both factors. The effect of target width on movement accuracy was less consistent. The observed effects are discussed in terms of a mass-spring model of muscular action. It is concluded that apart from having important consequences for the design of positioning experiments, these results call into question information-processing and impulse-variability theories which implicate movement amplitude in determining movement accuracy, and support theories which emphasize target location.
The NRC 'stressalyser' is a step-input subject-paced pursuit tracking task used to detect the effects of various extrinsic factors on skilled performance. It gives measures of reaction time, movement time, error score and overshoot score, each at four levels of the relevant within-task variable (directional probability, target distance or boundary distance). Several investigations have shown how these measures vary with such factors as sleep loss, time of day, alcohol, insulin-induced hypoglycaemia and diazepam, and thus demonstrate the applicability of the device to many applied problems of performance impairment.
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Listeria monocytogenes was isolated from both the blood and the synovial fluid of a diabetic patient with a septic arthritis involving the ankle.
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Subjects lving in the high Arctic carried out performance tests at the ends of the dark and light seasons and the intervening transitional seasons. In all four seasons, subjects showed circadian rhythms of performance. Rhythms for speed and accuracy were opposite in phase. The results show that normal rhythms are maintained when subjects follow a customary 24-h work pattern even though solar light-dark cycles are absent.
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We investigated by molecular hybridization whether T cells contain RNA sequences homologous to RNA which codes for immunoglobulin kappa-chain (k-chain). A radioactive probe of complementary DNA (cDNA) was prepared by transcription of purified k-chain mRNA from mouse myeloma MOPC-41 with reverse transcriptase (RNA-dependent-DNA nucleotidyltransferase) from avian myeloblastosis virus. The cDNA probably corresponded only to the constant region and 3'-terminus of k-chain mRNA. Kappa-chain cDNA was found to hybridize efficiently with RNA from both thymus cells and an established culture of thymoma cells. The thymus and thymoma cells contained 99.8% and 100% theta-positive cells, respectively. Quantitatively the average thymus T cell (thymus derived lymphocyte) contained about one half as much k-chain mRNA as the average spleen B cell ("bursa" dependent lymphocyte), whereas the thymoma cells contained only 1/33 as much. Control hybridizations of k-chain cDNA with myeloma and liver RNA support the conclusion that T cells in the thymus and in the thymoma cell line synthesize k-chain mRNA-like molecules. The thermal stability of hybrids of k-chain cDNA with RNA from spleen, thymus, thymoma, and another k-chain producing myeloma tumor was lower than that with MOPC-41 RNA. This finding may be due to the existence of several slightly different ck genes in the mouse as suggested by various control experiments.
Pilots and flight attendants flying scheduled services between Vancouver and Tokyo and between Toronto and Rome were tested on a tracking task before and after flights in each direction. Flights were included in schedules involving both 24-h and 7-d layovers at the overseas station. During these periods, they recorded their sleep patterns. The data showed that, following flight, subjects made an immediate attempt to adapt their behaviour to local time and the changes in their performance scores could be interpreted on that basis. It was concluded that behavioural circadian rhythms adapt rapidly to a new time zone.
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A retrospective questionnaire study investigated gender differences in the relations between the self-reported self-esteem of 155 psychiatric adult outpatients and their recalled experience of their parents' behavior toward them as children. There were no significant sex differences in degree of self-esteem. However, it had a higher correlation to parenting variables for the men than for the women, with maternal predictor variables accounting for 36% and paternal predictors accounting for 32% of the variance in the men's self-esteem. Neither combined maternal nor combined paternal variables were significant predictors for women. For men, parental acceptance/ autonomy was significantly and positively related and inconsistency negatively related to self-esteem. Paternal rejection but not maternal rejection was significantly associated with low self-esteem only for the women. The greater amount of variance explained by childrearing variables in the men's self-esteem scores was attributed to the earlier ego development and consequent increased individuation in women.