Genetic structure of the small yellow croaker (Larimichthys polyactis) across the Yellow Sea and the East China Sea by microsatellite DNA variation: implications for the division of management units.

The small yellow croaker, Larimichthys polyactis, is a commercial fish of the order Perciformes that mainly inhabit estuaries and coastal waters.In recent years, the resources and catch of L. polyactis have undergone huge fluctuations. To detect genetic variations caused by the fluctuation of resources, genetic diversity of L. polyactis in the coastal waters of China were analyzed in this study using microsatellite DNA marker. The results revealed high genetic diversity of this species. The STRUCTURE, DAPC and F ST results all indicated that there was no genetic structure consistent with the distribution pattern. Overall, our main findings are in agreement with previous studies, indicating that L. polyactis showed high genetic diversity and low genetic differentiation. Our results for high genetic connectivity among L. polyactis localities provide insights into the development of management strategies, that is, to manage this species as a single management unit.

Socioeconomic inequalities in mental distress and life satisfaction among older Chinese men and women: The role of family functioning.

Despite growing concern over socioeconomic inequality in health, few studies have focused on health inequality among older adults. The present study examined the independent and joint effects of socioeconomic status (SES) and family functioning on mental health and subjective well-being and explored the gender differences in such relations. Representative survey data on older adults (N = 1,432) were drawn from the third wave of the Hong Kong Panel Study of Social Dynamics conducted in 2015. Descriptive analyses and ordinary least-squares regressions were conducted for data analysis. The results demonstrate that receipt of means-tested welfare payments was associated with more severe mental distress and lower life satisfaction; living in private (as opposed to public or subsidised) housing was associated with better mental health; whereas holding investments and larger residence size were related to higher life satisfaction. Moreover, greater family functioning predicted better mental health and greater subjective well-being and mitigated the detrimental effects of low SES. Gender differences were observed concerning the effects of different predictors. The findings could inform the development of health-promotion services sensitive to gender and socioeconomic differences and facilitate integration of individual- and family-level services for older adults.

Demographic history and population genetic analysis of Decapterus maruadsi from the northern South China Sea based on mitochondrial control region sequence.

Late Pleistocene climate oscillations are believed to have greatly influenced the distribution, population dynamics, and genetic variation of many marine organisms in the western Pacific. However, the impact of the late Pleistocene climate cycles on the demographic history and population genetics of pelagic fish in the northern South China Sea (SCS) remains largely unexplored. In this study, we explored the demographic history, genetic structure, and genetic diversity of Decapterus maruadsi, a typical pelagic fish, over most of its range in the northern SCS. A 828-832 bp fragment of mitochondrial control region were sequenced in 241 individuals from 11 locations. High haplotype diversity (0.905-0.980) and low nucleotide diversity (0.00269-0.00849) was detected, revealing low levels of genetic diversity. Demographic history analysis revealed a pattern of decline and subsequent rapid growth in the effective population size during deglaciation, which showed that D. maruadsi experienced recent demographic expansion after a period of low effective population size. Genetic diversity, genetic structure, and phylogenetic relationship analysis all demonstrated that no significant genetic differentiation existed among the populations, indicating that D. maruadsi was panmictic throughout the northern SCS. Periodic sea-level changes, fluctuation of the East Asian Monsoon, and Kuroshio variability were responsible for the population decline and expansion of D. maruadsi. The demographic history was the primary reason for the low levels of genetic diversity and the lack of significant genetic structure. The life history characteristics and ocean currents also had a strong correlation with the genetic homogeneity of D. maruadsi. However, the genetic structure of the population (genetic homogeneity) is inconsistent with biological characteristics (significant difference), which is an important reminder to identify and manage the D. maruadsi population carefully.

Effects of Neighborhood Discrimination Towards Mainland Immigrants on Mental Health in Hong Kong.

Using data from a representative sample of Chinese adults who were surveyed in the Hong Kong Panel Study of Social Dynamics (HKPSSD), we estimate the effects of neighborhood discrimination towards immigrants from Mainland China on the mental health of Chinese residents in Hong Kong. Contrary to our expectations, discrimination towards immigrants from Mainland China measured at the neighborhood level is not associated with the poor mental health of post-1997 immigrants; instead, a higher level of immigrant discrimination is associated with a lower level of psychological distress for both post-1997 Mainland immigrants and other Chinese residents in Hong Kong. A functional family also appears to be a consistent predictor of better mental health for both groups. Our findings, therefore, suggest that immigrant discrimination can signify a prejudice that leads to social distance or avoidance and that the post-1997 Mainland immigrants do not have extensive contact with other local residents in Hong Kong. Although local residents' discriminatory attitudes may not result in aggressive behaviors that have a negative impact on newcomers' mental health, the social distance between the immigrants and the local residents is still an issue that requires further research and practical attention.