The nature of the association between diet and serum lipids in the community: a twin study.

Diet is commonly thought to be an environmental influence on serum lipid concentrations. This study evaluated whether total caloric and fat intake predict total cholesterol (TC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and triglyceride (TRIG) concentrations for environmental, as compared with genetic, reasons among 137 monozygotic and 67 dizygotic young adult twins. When genetic influences were controlled by correlating differences between monozygotic co-twins, a significant association remained between diet and TC, LDL, and HDL, suggesting that these dietary and serum lipid measures correlate for environmental reasons. Twin structural equation modeling confirmed these results. Overall, these results provide additional support for the hypothesis that diet is an environmental influence on TC, LDL, and HDL.     

Optimism and Coping with Unemployment among Hong Kong Chinese Women

The effects of dispositional optimism and coping on the link between unemployment and psychological health were studied among 79 employed and 104 unemployed Hong Kong Chinese women. Results indicated that optimism, indexed by the Chinese version of the Revised Life Orientation Test (C-RLOT), moderated the effect of unemployment on psychological health. The less optimistic women were more psychologically impaired by losing their jobs. Among the unemployed women, the more optimistic ones and those who were more able to distance themselves from job loss fared better. Nevertheless, coping did not mediate the connection between optimism and psychological outcomes. These findings suggest that optimism is an important personal resource for coping with unemployment in Hong Kong Chinese, but whether coping mediates the effects of optimism on psychological health or not depends on other contextual factors. Ways to ensure more reliable prediction regarding the connections between optimism, coping and psychological health in future research were discussed.     

The structure and prevalence of behavioral problems in Hong Kong preschool children

Nearly all 3-year-old Chinese children in Hong Kong attend preschool facilities, making it possible to study their behavior in a group learning situation based upon teachers' perception. The Preschool Behavior Checklist (PBCL), a teacher's questionnaire, was applied to a random sample of 851 Chinese children, ages 36 to 48 months. The factor structure of the PBCL was very similar to that obtained from its original British study, supporting its usage cross-culturally. Prevalence of behavior disorder was high as defined by the PBCL. This reflected specific cultural demands at school settings. Significant sex differences were also found in the overall rate of behavior disorder and symptom patterns. As in other studies, boys had more hyperactive, conduct, and speech problems. The results suggested a certain degree of universality of symptomatology for children at the preschool level.This project was funded by the Hong Kong Society for Child Health and Development. We are grateful to all the kindergartens and child care centers which participated in this project. Valuable assistance was provided by the Education Department and the Medical Health Department.     

A recruitment theory of force-time relations in the production of brief force pulses: the parallel force unit model

A theory, the parallel force unit model, is advanced in which the buildup and decline of force in rapid responses of short duration are assumed to reflect variability in timing of several parallel force units. Response force is conceived of as being a summation of a large number of force units, each acting independently of one another. Force is controlled by either the number of recruited force units or the duration each unit contributes its force. Several predictions are derived on the basis of this theory and are shown to be in qualitative agreement with empirical findings about both the mean and variability of brief force impulses. The model also has consequences for the temporal properties of a response. For example, under certain circumstances, it predicts a reciprocal relation between reaction time and response force. Although the theory is proposed as a psychological account, relations between the assumptions and basic principles in neurophysiology are considered. Possible future applications and generalizations of the theory are discussed.