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Some epidemiological studies have confirmed the association between environmental factors and congenital heart defects (CHD). While the possibility that maternal ambient heat exposures are related to CHD has received little attention. Our study aims to investigate the association between maternal ambient extreme heat exposure early in pregnancy and the risk of CHD in offspring in China. We conducted a retrospective cohort study of 1,918,105 fetuses between 2 and 8 weeks after gestation from May to October in Guangdong, China, 2015–2019. The main heat exposure was defined as extreme heat events (EHE) by using the 90th (EHE90) or 95th (EHE95) percentile of the daily maximum temperature. For each EHE definition, we further defined four indicators: having EHE or not, frequency, duration, and cumulative days. We used the log-binomial regression models to calculate the prevalence ratios (PR) of CHD with 95% confidence intervals (CI) for the associations between CHD and EHE, adjusted for potentially confounding covariates. There are 1,918,105 infants included in the study, of which 9588 had CHD, with a prevalence rate of 499.9 per 100,000 (95% CI: 489.9, 509.8). We found that all EHE indicators were positively associated with the increased risks of overall CHD, some CHD classes (congenital malformations of cardiac septa, congenital malformations of great arteries, and congenital malformations of great arteries), and some CHD subtypes (atrial septal defect and patent ductus arteriosus). In addition, the PR yielded higher estimates when exposing to EHE95. For instance, the risk of suffering congenital malformations of great arteries was 1.548 (95% CI: 1.401, 1.712) for EHE90 exposure and 1.723 (95% CI: 1.565, 1.898) for EHE95 exposure, respectively. Our study demonstrated that EHE during 2–8 weeks postconception was associated with overall CHD in offspring, particularly atrial septal defects and patent ductus arteriosus. The associations strengthened with the extent and cumulative days of maternal exposure to EHE. [ABSTRACT FROM AUTHOR]

Objectives: Parental psychological control is a stressor that may provoke children's aggression. However, whether there are bidirectional associations between parental psychological control and children's physical aggression remains unclear, as does the mechanism underlying these associations. Using an autoregressive cross-lagged model, the present study tested (a) the extent to which parental psychological control predicts physical aggression and vice versa, and (b) whether child impulsivity explains this bidirectional association. Methods: Data were collected across three time points (fall semester of 4th grade, spring semester of 4th grade, and fall semester of 5th grade). A sample of 689 children (385 boys, 304 girls) completed questionnaires regarding parental psychological control, impulsivity and physical aggression. Gender, age and socioeconomic status were controlled in the analyses. Results: As hypothesized, the findings showed that there was a direct longitudinal connection from parental psychological control to child physical aggression, and the inverse relation was also significant. Moreover, the results demonstrated an indirect link from parental psychological control to physical aggression via child impulsivity, but the inverse effect was not significant. Conclusions: Our findings suggest that there is a reciprocal relationship between parental psychological control and children's physical aggression, and that the parent-driven component of this bidirectional process is mediated by child impulsivity. The results have potential applied value for prevention and intervention. [ABSTRACT FROM AUTHOR]

A class Γ of graphs is vertex Ramsey if for all H∈Γ there exists G∈Γ such that for all partitions of the vertices of G into two parts, one of the parts contains an induced copy of H. Forb ( T,K) is the class of graphs that induce neither T nor K. Let T(k, r) be the tree with radius r such that each nonleaf is adjacent to k vertices farther from the root than itself. Gyárfás conjectured that for all trees T and cliques K, there exists an integer b such that for all G in Forb( T,K), the chromatic number of G is at most b. Gyárfás' conjecture implies a weaker conjecture of Sauer that for all trees T and cliques K, Forb( T,K) is not vertex Ramsey. We use techniques developed for attacking Gyárfás' conjecture to prove that for all q, r and sufficiently large k, Forb( T(k,r),K) is not vertex Ramsey. [ABSTRACT FROM AUTHOR]