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At least 109 records · Page 6Linked to original sources
PubMed1975

Some effects of ACTH 4-10 on performance during a serial reaction task.

Eighteen subjects worked continuously for half an hour in a self-paced reaction task. Half of the subjects were injected with ACTH 4-10 (30 mg/s.c.) and the other half with a placebo. The subjects injected with ACTH 4-10 showed a larger improvement in reaction time during the experimental session than the placebo group. However, this effect disappeared in a short retest, which was given half an hour after the experimental session. These results suggest that ACTH 4-10 has no effect on skill acquisition, but counteracts the build-up of reactive inhibition during the experimental session; that is, the peptide suppresses the decrease in motivation, which usually occurs during continuous performance tasks. This notion is confirmed by an analysis of the frequency distributions of the reaction times. Treatment effects were only found for the long reaction times. Long reaction times tend to occur with increasing frequency as a function of time-on-task and are an indication for the level of motivation of the subject. It was concluded that ACTH 4-10 counteracts the usual decay in performance as a function of time-on-task due to increasing boredom and mental fatigue.

Adrenocorticotropic Hormone↗
PubMed1988

Instrument flight performance under the influence of certain combinations of antiemetic drugs.

Two different combinations of antiemetic drugs were evaluated using a digital flight simulator. Drug treatments consisted of a lactose placebo, a combination of thiethylperazine (10 mg) and cimetidine (300 mg), and a combination which added promethazine (25 mg) to the two-drug combination. The performance effects of these combinations were evaluated on both a dual task (instrument flight task with the Sternberg Memory Scanning task) and a single task condition (Sternberg task only) for 3 h post drug ingestion. Analysis indicated a significant treatment effect on three of the six flight performance variables and that the three-drug combination, containing promethazine, was primarily responsible for the decrease in performance. Implications for operation in a radiation environment are that thiethylperazine and cimetidine will not cause significant performance decrements, but the addition of promethazine to those two drugs will significantly impair performance. The Sternberg task was sensitive to changes in workload.

Adult↗
PubMed1992

Characterization of the physical demands of firefighting.

To characterize the physical demands associated with on-the-job use of current firefighting equipment and the performance of essential firefighting operations, an initial task analysis of all firefighting operations was followed by an in-depth physical and physiological characterization of those tasks deemed to be physically demanding. The most commonly encountered applications of strength and endurance were lifting and carrying objects (up to 80 lbs), pulling objects (up to 135 lbs), and working with objects in front of the body (up to 125 lbs). The most demanding firefighting operations required a mean VO2 of 41.5 ml/kg.min-1 with peak lactate concentrations of 6 to 13.2 mM. Ninety percent of the demanding firefighting operations that were studied required a mean VO2 of 23 ml/kg.min-1. These aerobic energy requirements corresponded to 85 and 50% VO2max, respectively. Therefore a minimum VO2max standard for firefighter applicants of 45 ml/kg.min-1 is recommended.

Adult↗
PubMed1976

Laboratory investigation of "biorhythms".

Three subjects were tested on an information processing task on a daily basis for a period of 70 d. Performance measurement included reaction time, movement time, and information processing rate. The data set obtained was subjected to Fast Fourier Transforms (FFT) in an attempt to identify periodicities in performance. Twelve significant harmonics were identified and nine were found to be within 1 d of at least one of the cycles hypothesized by the theory of "biorhythms." The probability of this occurring by chance is remote (p less than 0.05), assuming a uniform distribution of significant amplitude. The results were interpreted as suggesting the possibility of a biorhythmic influence in the performance of the task.

Adult↗
PubMed1976

The effects of divided attention on information processing in manual tracking.

Six subjects performed a manual tracking task concurrently uith each of two secondary tasks: in input task (auditory signal detection) and an output task (application of a constant force). A feedback-control analysis of tracking performance was utilized to analyze the time-sharing decrements observed in mean squared errer, in terms of components due to processing delay, addition of internal processing noise, and change in response bias (tracking gain). The results indicated that only the parameters measuring noise and gain were sensitive to time-sharing conditions, and these only to concurrent performance of the force application task. It is concluded that limits of attention in dual-task performance are more severe in output than in input stages of processing, but that these limits are not necessarily those of a single-channel bottleneck. Instead, a broader conception of attention is proposed: one that included changes in processing noise and shifts in response bias, as attention-related phenomena.

Attention↗
PubMed1978

Performance and efficiency of intercollegiate cross-country skiers.

Ten male intercollegiate cross-country skiers were studied to identify factors influencing competitive performance and to estimate the efficiency of energy expenditure in skiing. The variables examined were maximum oxygen intake, as determined by both uphill treadmill running and by maximal level skiing, physical characteristics, strength and experience in cross-country skiing and racing. Multiple regression analysis showed that racing experience, cardiorespiratory fitness, and body fat percentage were significant factors in racing success. The net mechanical efficiency at this level of competition was estimated at 21.3%.

Adolescent↗
PubMed1990

Genetic influences on respiratory sinus arrhythmia across different task conditions.

Respiratory sinus arrhythmia (RSA) has been shown to be a sensitive index of vagal cardiac control. We studied the genetic and nongenetic influences on individual differences in RSA in a sample of 160 adolescent twins. RSA was measured during rest and across two different tasks. Results show that heritability is task dependent. The amount of genetic variance is the same, however, during rest and task conditions. Because nonshared environmental variance decreases during tasks, heritability is larger for RSA measured under more stressful conditions than for RSA as measured during rest. Multivariate models assessed the continuity of the genetic and environmental influences and show genetic influences to be the same across different conditions, while environmental influences are different. More specifically, a one-factor model is found for genetic influences and a second-order autoregressive model for the environmental factors.

Adolescent↗
PubMed1990

[Basic research on measurement of mental work load utilizing physiological information].

Various definitions and models have been proposed to evaluate mental work load, for example, task time analysis method and secondary task method based on single channel model. However, an evaluating method utilizing physiological information has been comparatively newly proposed. Therefore, this method has not been adequately examined with respect to its relation to be heretofore proposed methods and to its practical usefulness in evaluating mental work load. In this study comparison was made of various evaluating methods, i.e. task time analysis method, secondary task method, method utilizing physiological information, and subjective score method with emphasis on the method utilizing physiological information when a modeled experiment was conducted. In evaluating the regression by the experimental results, the adopted standard was time shared fraction (TSF), which was computed as the relative required time compared to actual permitted time based on the single channel model. The main results can be summarized as follows: (1) The evaluated TSF value is a useful index if it can be computed, because it reflects the individual ability of each subject, is proportional to the amount of given information, and is most faithful to the definition of single channel model. (2) The TSF value is significantly correlated to the value obtained by existing secondary task method and subjective score method. Thus, this result justifies the above mention. (3) In the adopted physiological indicators of this experiment, SRRP (skin resistance reflex pulse rate) has the strongest correlation to TSF value. Furthermore, this SRRP is relatively not affected by individual difference and is significantly correlated to subjective score and secondary task in the constant condition of atmospheric temperature and subject's arousal level and in the repetitive task.

Adult↗
PubMed1988

Evaluation of five systems to determine technician staffing in a unit dose cart-filling area.

The development and evaluation of predictive systems to determine staffing needs in a centralized unit dose cart-filling area were studied. Data concerning actual cart-filling time and the hospital's daily census, by total beds and by bed type, were collected over 55 days. Four predictive systems were then developed, as follows: simple average, range average, simple regression, and multiple regression. In addition to these mathematical systems, a pharmacist "best-guess" system was devised, whereby the pharmacist directing the cart-filling area estimated the staffing needs on a daily basis during the trial period. The five systems were then used to predict cart-filling time daily over 14 days. During this time, the actual filling time was recorded and compared with the times predicted by the five systems. The differences among the actual or predicted mean cart-filling times for the five systems were not significant. The pharmacist best-guess system was on average the most accurate in detecting different staffing needs; the advantage of this system is that the pharmacist can evaluate differences in work habits among the scheduled technicians, which the mathematical models would be unable to do. The simple average system correlated well with changes in filling time and most precisely predicted variability in census. Although none of the systems was superior in all respects, a combination of the pharmacist best-guess and simple-average systems appeared to be the best method for predicting daily technician staffing needs in the central cart-filling area.

Data Collection↗
PubMed1977

Cost of using permanent vs. disposable ware. Studies in two school systems.

In this study, the cost of using permanent ware and disposable ware in selected schools was compared. Included in the permanent ware study were the costs of: The ware, machine washing of the ware (including labor time and consumption of utilities, detergents, and chemicals), and refuse removal. Data collected in the disposable ware study were: Meal count; number of items of ware used; labor time; and cost of equipment, supplies, and refuse removal. The cost per student was 4 cents for permanent ware and 10 cents for disposable ware. Although the findings in the schools studied point to an economic advantage in using permanent ware, other considerations might prompt a decision in favor of disposable ware.

Cooking and Eating Utensils↗
PubMed1991

A microcomputerized task assessment of cognitive change in normal elderly and young adults.

There is need for efficient, acceptable quantitative measures of cognitive differences with senescence which, in addition, have potential to discriminate mild dementia from the performance of normal elderly. A microcomputerized method designed to assess attentional capacity was administered to two elderly age groups, 68-79 and 80-87 years of age. A comparison group of young adults, 25-35 and 35-45 years of age, was similarly studied. The two tasks in the procedure (the tracking task, consisting of following a randomly moving target on a video screen, and the probe task, consisting of visual monitoring of a randomly elongating dot in the video screen) are performed separately and then simultaneously (dual task). The tracking task discriminated between the younger groups. Both the tracking and the probe task discriminated between the two older age groups. On discriminant analysis, the best variables for distinguishing older age groups were the logarithms of the single task scores. The performance scores of both elderly age groups were lower on the dual tasks compared with single tasks, but with significant performance decreases only in the probe scores. Comparing all four age groups, the older groups performed less well on the tasks and particularly poorly on the dual tasks. There were no significant gender effects. These initial data will be useful in application of the method for purposes of discriminating mild dementia from normal senescence, and possibly the effects of drugs used to enhance cognitive function.

Adult↗
PubMed1992

Clarification of the dual task dilemma: lateralized effects for perfunctory and purposeful tasks in left- and right-handed males.

The hypothesis that behavioral asymmetries with the dual task paradigm represent manual dominance was investigated with right- and left-handed males performing verbal and spatial tasks ordered by complexity. Lateralization was assessed for nonideational (perfunctory) and ideational (purposeful) components of tasks with multivariate and ANCOVA procedures. The outcomes of prerequisite tests showed the assumptions for conducting ANCOVA procedures were not satisfied with different handedness groups in the same design. However, results of the multivariate analyses suggest lateralized effects are more likely to represent the cognitive task when interference is high and may represent manual dominance when interference is low.

Adult↗