Relationship of Family Environment, Psychological Resilience, Campus Bullying with Tobacco Use among Preadolescents

Objective. To explore the relationship between family environment, psychological resilience, campus bullying and tobacco use in early adolescence. Methods. According to the principle of cluster sampling, 4,792 students from grade 4 to grade 6 in five primary schools in Baise City and county were selected from February to November 2018, including 2,522 males (52.63%), 2,236 females (46.66%)and 34 missing genders (0.71%); the average age was (11.8 ± 0.5) years; 2,721 students in urban areas (56.78%) and 2,071 students in county towns (43.22%); 4,313 Zhuang (90.00%), 365 Han (7.62%), 98 other ethnic groups (Yao, Miao, Yi, etc.) (2.05%). The General Family Environment Questionnaire, Adolescent Mental Resilience Scale, School Bullying Questionnaire, and Tobacco Use Questionnaire were used for evaluation, and logistic regression was used to analyze the effect relationship between the study variables. Results. 467 people tried to smoke, and the total detection rate was 9.75%. The number of smokers was 334, and the total detection rate was 6.97%. Boys’ tobacco attempt and smoking behavior were higher than girls (χ2 were 57.230 and 56.013, P < 0. 001). Multivariate logistic regression analysis showed that the risk of tobacco attempt of boys was 2.37 times thanthat of girls (OR = 0.468, 95% CI 0.377 ~ 0.582), the risk of smoking in boys is 2.5 times that in girls 32 times (OR = 0.422, 95% CI 0.324 ~ 0.551); older adolescents had more tobacco attempts (OR = 1.609, 95% CI 1.446 ~ 1.791)and smoking behavior (OR = 2.026, 95% CI 1.776 ~ 2.310); campus bullying increased the risk of smoking behavior among adolescents (OR = 1.106, 95% CI 1.073 ~ 1.140). Psychological resilience (personal strength), family intimacy and family rules can effectively reduce the risk of adolescent tobacco attempts (personal strength, OR = 0.964, 95% CI = 0.951 ~ 0.976; family intimacy, OR = 0.946, 95% CI 0.892 ~ 0.984; family rules, OR = 0.949, 95% CI 0.930 ~ 0.965) and smoking behavior (personal strength, OR = 0.962, 95% CI 0.947 ~ 0.977; family intimacy, OR = 0.937, 95% CI 0.885 ~ 0.992; family rules, OR = 0.952, 95% CI 0.932 ~ 0.973). Conclusion. Campus bullying increases the risk of smoking behavior among adolescents. Psychological resilience (personal strength), family intimacy and family rules can effectively reduce teenagers’ tobacco attempts and smoking behavior

Temporal variation of gravity field before and after Wenchuan Ms8. 0 earthquake

Absolute and relative gravity data during 1998 to 2008 were used to study gravity field and temporal variation in the North–south seismic-belt region, and their correlation with seismic activities before and after Wenchuan Ms8. 0 earthquake. The temporal variation of gravity field shows that the portentous information of the gravity field reflects the development and occurrence of earthquake more clearly. The variations of gravity field are inhomogeneous in the space-time distribution, and are associated with the development and occurrence of the Wenchuan Ms8. 0 earthquake, also closely connected with active fault tectonics

Gravity evidence of underplating in the northeastern margin area of Qinghai-Tibet plateau

Based on leveling data in 1972–2011 and relative-gravity data in 1993–2011, we obtained a long-term vertical crustal-deformation rate of 1. 62 mm/a and a relative-gravity variation rate of 0.62×10 −8 ms−2a−1 for the northeastern margin area of Qinghai-Tibet plateau. After removing the contributions from the observed vertical movement and inferred surface denudation, we obtain a gravity-variation rate of 0.73×10−8 ms−2a−1 attributable to the mass changes beneath the crust. This positive change suggests that the total mass under the observation stations was gradually increasing. We consider this result to be the gravitational evidence of under-plating beneath the study area, and propose that the underplating was caused by collision betwen the Indian plate and Tibetan plateau and by gravitation-potential induced deviatoric stress

Comprehensive study of plastic deformation mechanism of polycrystalline copper using crystal plasticity finite element

Graded polycrystalline copper materials have been expected in the field of scientific research and engineering in recent years because the core of the material has enough toughness and a sufficient surface strength. However, the plastic deformation mechanism, gradient grain generation mechanism and material strengthening principle of polycrystalline copper are still not well understood. Therefore, it is urgent to further analyze the plastic deformation of polycrystalline copper. In this study, the micron scale plastic deformation behavior of polycrystalline copper is simulated based on the crystal plasticity finite element method. The simulation analysis is carried out from the aspects of grain size, grain shape, crystal orientation type and quantity, loading mode and so on. The effects of the above parameters on the Mises stress nephogram and stress-strain curve of polycrystalline copper were analyzed. At the end of the article, the EBSD orientation distribution information of graded polycrystalline copper grains obtained in the cutting process is analyzed comprehensively and the formation mechanism of graded polycrystalline copper is explained by combining the simulation results