Cyclicity and synchrony of historical outbreaks of the beech caterpillar,Quadricalcarifera punctatella (Motschulsky) in Japan

Historical records of the incidence of defoliation caused by the beech caterpillar,Quadricalcarifera punctatella (Motschulsky) in northern Japanese prefectures from 1910–1993 were used to characterize the cyclicity and synchrony of outbreaks. Cyclicity and synchrony were quantified using standard Box-Jenkins time series methods as well as spectral analysis and simple Markov models. Statistical analysis of these records indicated the presence of quasi-periodic behavior with 8–11 yr between outbreaks. Outbreaks tended to occur synchronously among different prefectures, though the onset of outbreaks was typically lagged. This study illustrates the use of specific statistical methods for characterizing cyclicity and synchrony from crude records of the presence/absence of outbreaks.     

中国经济转型过程中的人口因素

文章试图对25年来中国经济与人口变化过程尤其是人口因素在经济转变中的作用加以评估。在回顾与总结了这一时期人口变化的主要指标的基础上,然后通过介绍和使用两个“人口红利”的概念与方法,就过去25年中人口变化对中国经济发展的有利作用做出估算,并对未来人口变化,尤其是人口老龄化对经济发展的可能影响与机遇加以评估。最后,对中国近期人口变迁所产生的几项社会后果进行讨论。     

Parental divorce in childhood and demographic outcomes in young adulthood

We investigated the long-term effects of parental divorce in childhood on demographic outcomes in young adulthood, using a British longitudinal national survey of children. Our analyses control for predisruption characteristics of the child and the family, including emotional problems, cognitive’ achievement, and socioeconomic status. The results show that by age 23, those whose parents divorced were more likely to leave home because of friction, to cohabit, and to have a child outside marriage than were those whose parents did not divorce. Young adults whose parents divorced, however, were no more or less likely to marry or to have a child in a marriage. Moreover, even in the divorced group, the great majority did not leave home because of friction or have a child outside marriage.     

The effect of children on marital dissolution

The relationship between the presence of children and divorce and separation is examined using data from the first four years of the National Longitudinal Surveys of Labor Market Experience in Women Aged 30 to 44. The data show that children were a deterrent to separation and divorce only when they were in the preschool ages. Once all the children in a family were in school, they did not seem to influence the probability of separation and divorce. It is suggested that the high costs of child care for preschool children, in terms of time, money, and effort, act as a deterrent to marital dissolution. The associations between several other social demographic variables and marital dissolution also are investigated.     

Guidelines for time use data collection

Growing and widespread interest in time begs the need for time use data collection and reporting standards. Initial guidance for comparative work was provided by the Multinational Time Use Project. However, changing technologies, methodologies, and divergent data needs have given rise to the need for updated guidance. This paper, prepared with input from members of the International Association for Time Use Research, examines the history and applications of time use data, identifies and evaluates methodological options for time use studies, recommends options facilitating cross-national and cross-temporal comparability and identifies methodological challenges facing time use researchers. The study concludes that alternative collection methods appear to make little difference in the resulting activity and time use estimates at customary levels of reporting.     

Understanding the sex ratio in India: A simulation approach

The highly masculine sex ratio in India has increased substantially in the twentieth century, in contrast to most other countries in the world. Competing arguments alternatively posit under-enumeration, highly masculine sex ratios at birth, or excess female mortality throughout the life course as the factors underlying the level of the overall sex ratio; these arguments have not been resolved. Based on population projections that simulate population dynamics, our findings show that small differences in mortality at young ages, persisting over a long period, as well as a sex ratio at birth of 106 males per 100 females, result in a highly masculine population sex ratio.     

Child development and family resources: Evidence from the second generation of the 1958 British birth cohort

Studies of American and recently British children suggest that there is a link between family income and child development, in particular that one consequence of child poverty is to hold back cognitive development. This paper investigates the impact of family income, material deprivation, maternal education and child-rearing behaviour on an indicator of cognitive functioning, using British data on children aged 6 to 17 whose mothers are members of the 1958 Birth Cohort Study. The poorer average cognitive functioning among children from the lowest income groups could largely be accounted for, statistically, by the greater material disadvantage of these groups. These analyses provide evidence to suggest that low income has detrimental effects on children's cognitive functioning through the operation of longer-term material disadvantage, and that these effects may be mitigated by positive parental behaviours. Received: 31 July 1999/Accepted: 26 September 2000     

Welfare,work, and changes in mothers’ living arrangements in low-income families

Data from a two-wave survey of low-income families in Boston, Chicago, and San Antonio are used to replicate recent reports of a modest increase in the number of low-income children living in two-adult families and to analyze the increase. We find that most of the increase occurred through the addition of a man other than the biological father to the household and that more of it occurred through cohabitation than through marriage. Moreover, across the two waves, cohabiting and marital unions were highly unstable. We review research on stepfamilies and on instability in childrens living arrangements, and we conclude that the kinds of two-adult families being formed in these low-income central-city neighborhoods may not benefit children as much as policy-makers hope. In addition, we investigate the associations between marital and cohabiting transitions, on the one hand, and transitions into and out of Temporary Assistance to Needy Families (TANF) receipt, employment, and Earned Income Tax Credit (EITC) usage between the two waves on the other. We find that marital transitions are related to TANF and employment transitions but that cohabiting transitions are not. We suggest that low-income mothers may view marriage as more of an economic partnership than cohabitation and may expect more of an economic contribution from a husband than from a cohabiting partner.     

Community action in Alabama's Black Belt Timber-Dependent communities

The current decline in the economic well-being of the residents of the Alabama's Black Belt communities is well documented. High poverty rates, limited job growth, falling real per capita income, and increased out-migration are signs of current economic problems. With the resurgence of interest in promulgating self-help and community action mechanism at the local, state, and national levels, the purpose of this research is to examine collective community action by local officials in the Black Belt Timber Dependent communities to meet the social and economic well-beings of local residents. Data from the case study research indicate that race is the primary factor in actions with a collective dimension in Forestville. Inequality based on race suppresses interaction among the residents whose lives and well-being are in fact tied together ecologically; and, without interaction, collective local action cannot exist. The community has not been hospitable to African Americans because they are viewed or seen as social inferiors and this view is expressed by many whites who grew up in the community. The white leadership discouraged collective action in order to maintain its hegemony in the community. The African Americans with political power have no resources and great exertion is needed to change established community relationships. In Forestville, racial and ethnic cleavages makes collective community actions to levelop local business and industry and human services impossible. Implications of the research findings are discussed.