Variability of sexual dimorphism of main anthropometric dimensions of newborns in connection with the degree of urbanization

The study embraces big volume of literary data – over 120 samples of newborns of each sex from former USSR of 1960s, including main anthropometric dimensions (height, weight, chest and head girths). The quantitative estimation of the level of sexual dimorphism (SeD) is accomplished using Kullback divergence – analogue of the Mahalanobis distance. The parameter of quantity of population of the residence place, associated with the income level, nutrition status and frequency of socially significant diseases, is used as the marker of the degree of urbanization. Results. The level of Sed of newborn infants has modest fluctuations and for most somatic traits has average meaning about 0,3 standard deviations, independently of the degree of urbanization of the residence place of territorial/ethnic groups. Still the living standards in big millionaire cities are favorable to the progress (improvement) of physical status of male infants – increase of head girth in Moscow megalopolis, increase of height/weight dimensions of both Russian and aboriginal newborns in Tashkent – which promotes some increase of Sed of somatic traits as well. Conclusion. Somatic dimensions of newborns are the classic object of stabilizing selection, hence have very moderate variability. In this context, quantitative meaning of SeD of body dimensions is also relatively stable.

Detection of Juvenile Sleep Deprivation by Stochastic Optimization of Pupillographic Records

Summary Objective: To address the challenging problem of measuring juvenile sleep deprivation, we test the hypothesis that a pupillographic method found successful for adult narcoleptics might also discriminate between sleep deprived juveniles acting as their own controls. Methods: A linear, nonstationary model relating pupillary diameter and a random photic stimulus are estimated by recursive regressions from pupillographic records of 8 juveniles of median age 7 years acting as their own rested controls. The estimated pupillary impulse response noise functions are stochastically optimized using the Kullback divergence measure to maximally separate the sleep deprived records from the control records. Results: Both the average and covariance statistics of the estimated pupillary noise functions exhibit statistically significant differences between sleep deprived and rested subjects. The main result is that sleep deprivation decreases pupillary noise variance; a finding consistent with a previous study of adult narcoleptics. Further, it was found that virtually the same stochastic parameters were optimal for the juvenile sleep deprived data and for the previous adult narcoleptic study. Conclusions: Although our results are preliminary, the consistent reduction of pupillary noise appears to justify a comprehensive clinical trial across a broad range of age classes. In addition, the finding that the same parameters stochastically optimze both juvenile and adult recordings suggests the procedure holds promise as a clinical test which could produce sleep deprivation measures simultaneous with data collection.