Discriminative Grandparental Investment in China : Evidence from an Undergraduate Questionnaire Study.

Many studies in Western societies show a pattern of discriminative grandparental investment as follows: maternal grandmothers (MGMs) > maternal grandfathers (MGFs) > paternal grandmothers (PGMs) > paternal grandfathers (PGFs). This pattern is in line with the expectation from evolutionary reasoning. Yet whether or not this pattern applies in China is in question. The present study was based on a questionnaire survey at a university in Central China (N = 1,195). Results show that (1) when grandparent-grandchild residential distance during grandchildren's childhood is controlled, in the case of grandsons and granddaughters as a whole and granddaughters only, both grandparental caregiving and grandchildren's emotional closeness to grandparents display a rank order of MGM > MGF > PGM > PGF, but in the case of grandsons only, this order is not statistically significant. (2) There are stable relationships between grandparental caregiving/grandchildren's emotional closeness and residential distance/similarity in appearance. (3) The effects of residential distance on either PGFs' or PGMs' caregiving exceed those on either MGFs' or MGMs'. (4) The PGF and PGM prefer grandsons to granddaughters in their caregiving, whereas the MGF and MGM do not have a sex preference, and (5) the fact that the PGF and PGM invest more in grandsons than in granddaughters does not depend on grandsons' duration of living in a rural area. Our results suggest that (1) in general, the Chinese display a pattern of differential grandparental investment predicted by an evolutionary perspective, (2) the evolutionary perspective that combines the two factors of paternal uncertainty and sex-specific reproductive strategies is applicable to grandparental investment in China, and (3) the traditional son-preference culture also plays some role in affecting grandparental investment in China, though the roles of culture and urban-rural cultural difference should not be exaggerated.

[Air Pollution Characteristics and Jogger Inhalation Exposure in Typical Running Area of Beijing].

To investigate the exposure to major air pollutants of runners while running in Beijing, the concentrations of PM2.5, CO, O3, and NO2 were constantly monitored at typical park running areas (Tiantan Park and Olympic Sports Center), roadside running areas (Qianmen East Street and Yongding Inner Street), and a background area (Dinglin) during April, June, and October of 2016 and in January 2017. The concentration variation characteristics for the pollutants in different areas and at different times were analyzed. Using a numerical model of human respiratory exposure, 102 joggers were studied, as was the temporal-spatial variation of inhalation dose of pollutants. At typical running areas, the concentrations of CO, NO2, and PM2.5 were relatively higher in winter, whereas the concentrations of O3 were higher in spring and summer. The concentrations of CO, NO2, and PM2.5 were lower in the afternoon (16:00-18:00), whereas the concentrations of O3 were lower in the morning (06:00-08:00) and evening (18:00-20:00). There was a linear correlation between concentrations roadside to those in nearby parks, as the concentrations of CO roadside were generally consistent with those in parks (croad/cpark=1.01, R2=0.93), the concentrations of NO2 and PM2.5 roadside were higher than those in parks (croad/cpark were 0.56 and 1.19, respectively), and the concentrations of O3 roadside were lower than those in parks (croad/cpark=0.74, R2=0.97). During moderate or higher pollution conditions, 92% of joggers halted outdoor activities, 62.7% chose to jog in parks, 66.7% chose to jog at night, and 64.7% of joggers had single run mileages of 10-20 km. When people chose to jog in the afternoon and evening, the inhalation of CO, NO2, and PM2.5 were relatively lower, whereas the inhalation of O3 was higher. During spring and summer, night running after 20:00 reduced the O3 inhalation dose. Running roadside led to higher inhalation of CO, NO2, and PM2.5 than that in parks; however, O3 inhalation was lower.