A standardized method of evaluating exercise-induced asthma

In order to evaluate drug effects on exercise-induced asthma, and to study associated metabolic and pulmonary effects, a method for inducing a consistent response is needed. A method is presented, consisting of 5 min of treadmill exercise sufficiently strenuous to increase a subject's heart rate to 90% of the predicted maximum for age; the airway response is measured frequently for 20 min after exercise. Using this method, 48 asthmatics and 13 nonasthmatics were evaluated. Although none developed severe asthma, a significant airway response occurred in 71% of asthmatics. The severity of exercise-induced asthma depended on intensity and duration of exercise but not on time of day. The method described allows a consistent stress to be applied to a wide age range, and response to this stress was consistent at various ages. Variation of a subject's response following repeated testing was less than that reported with other methods, and could be further reduced by selecting only those subjects with greater than 20% change in one-second forced expiratory volume (FEV1) and by completing studies in less than a month.     

Application of a method of evaluating training.

Data were processed with Ward Edwards' formulation of value of training which includes estimates of proficiency level attained, worth of a trained man in dollars, and training costs in dollars. Difficulties which were encountered and techniques of overcoming them are reported. Results of the evaluation, which appear to be realistic, are reported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the sampling variance of intraclass correlations and genetic correlations

Widely used standard expressions for the sampling variance of intraclass correlations and genetic correlation coefficients were reviewed for small and large sample sizes. For the sampling variance of the intraclass correlation, it was shown by simulation that the commonly used expression, derived using a first-order Taylor series performs better than alternative expressions found in the literature, when the between-sire degrees of freedom were small. The expressions for the sampling variance of the genetic correlation are significantly biased for small sample sizes, in particular when the population values, or their estimates, are close to zero. It was shown, both analytically and by simulation, that this is because the estimate of the sampling variance becomes very large in these cases due to very small values of the denominator of the expressions. It was concluded, therefore, that for small samples, estimates of the heritabilities and genetic correlations should not be used in the expressions for the sampling variance of the genetic correlation. It was shown analytically that in cases where the population values of the heritabilities are known, using the estimated heritabilities rather than their true values to estimate the genetic correlation results in a lower sampling variance for the genetic correlation. Therefore, for large samples, estimates of heritabilities, and not their true values, should be used.     

关于平均数和标准差的一种简捷算法

在统计工作中,平均数(均值)和标准差是描述数据资料集中趋势和离散程度的两个最重要的测度值.但传统的计算方法过程较繁琐.本人通过长期讲授<统计学原理>,对上述两个测度值的计算方法进行了深入研究,推证出一种更实用而简捷的方法--ABCDE法,它可提高统计数据计算的速度和精确度,实性用较强.本文通过实例介绍了ABCDE法并加以证明.     

On the binocular summation of chromatic contrast

The binocular summation of chromatic contrast was investigated under a variety of stimulus conditions. Binocular and monocular contrast detection thresholds were measured using 0.5 cpd Gabor patches. It was found that, using stimuli which contained combinations of chromatic and luminance contrast, binocular detection could take place independently in luminance-contrast- and chromatic-contrast-sensitive mechanisms. It was also found that, with chromatic stimuli, levels of binocular summation were above those expected from probability summation between the eyes, and thus showed evidence for binocular neural summation within chromatic detection mechanisms. The implications of these results for (a) the binocularity of chromatic detection mechanisms, and (b) the suggested link between stereopsis and binocular neural summation, are discussed.