Whether complex indices of ambient air pollution can be used for sanitary ranging of primary facilities of the district was studied. The indices were calculated by using single air samples. The impact of "zero samples" on the results of calculation of the significance of differences in the single concentrations of individual chemical air pollutants was examined. The average annual concentrations of pollutants were calculated on the basis of average daily maximum allowable concentrations and the a-coefficient recommended by M. A. Pinigin. The database contains 20,000 definitions of the most hazardous chemical pollutants in the ambient air. Significant and insignificant values of chemical pollutants in single ambient air samples may be used in calculating complex indices as the rate of result coincidence was 80%, the suitability of insignificant values for ranging was confirmed in 81.25% of cases.
The paper deals with problems in teaching adolescents at different levels of education (medical lyceum--higher educational establishment (HEE)). Their health status, functional changes that can vary with the pattern of training are comprehensively assessed. The school-HEE program was found to be effective as the high progress of lyceum students causes worse health. The students' high process and low morbidity within an academic year is suggestive of their rapid adaptation to HEE studies.
Recurrent event data are frequently encountered in long-term follow-up studies. In many applications, the gap times between two successive recurrent events are natural outcomes of interest. Investigation on patterns of associations among recurrent gap times within subjects is an important inferential issue. In this paper, we introduce flexible functions of previous gap times to create a class of summary measures of serial associations for a sequence of recurrent gap times through Kendall's tau. Such a general class of serial association measures provides a useful tool to quantify the predictive abilities of event history with different aspects. Non-parametric estimators of the proposed measures of serial associations are developed by generalizing the existing estimator of Kendall's tau for two serial gap times, in which inverse probability of censoring weights is used to overcome the induced dependent censoring. Various tests are further constructed for testing the constancy of serial associations over different events. Our method is applied to Denmark schizophrenia data and the results show that association structures are different for distinct ages of onset of schizophrenia.