Modeling Seasonality in Fecundability,Conceptions, and Births

This paper develops a model of seasonal fluctuations in fecundability, conceptions, and births. We begin with a model of individual fecundability that combines behavioral and biological components, with particular attention to the roles of coital frequency, sperm concentration, fetal loss, and contraception. The individual-level model is then expanded into a model of seasonal fluctuations in births at the population level, which accounts explicitly for seasonal fluctuations in the size of the susceptible population. We illustrate the use of the model by analyzing proposed explanations of birth seasonality that rely on extreme summer heat.     

The impact of state-level restrictions on abortion

This research examines 23 different laws passed by state governments in an effort to restrict the number of abortions. It assesses both laws passed and laws actually enforced after the Supreme Court permitted states to restrict access to abortion in 1989. None of the policy actions by state governments has had a significant impact on the incidence of abortion from 1982 to 1992. Abortion rates continue to reflect past abortion rates, the number of abortion providers, whether the state funds abortions for Medicaid-eligible women, urbanism, and racial composition of the population. Recent restrictive policies have not affected these trends.     

Capital investment in neighborhoods: Theories which inform national urban policy in the United States

This article addresses two fundamental issues in the design and implementation of federal urban policies: (i) the shifting priorities of urban policy characterizing urban renewal, the Community Development Act, and recent neighborhood-oriented redevelopment efforts and (ii) the sociological theories which underlie such priorities. The first part of the article traces the shift in priority of national urban policy from an earlier focus on economic redevelopment and housing assistance for the economically disadvantaged to the more recent thrust toward neighborhood rehabilitation, revitalization, and stabilization. The central role of private sector economic involvement in the new urban strategies is discussed and the triage model of urban development is proposed to explain recent urban policy efforts. In the latter part of the article the sociological theories underlying many of the new urban policies are shown to contain inherent contradictions and inadequacies which were largely ignored by policy-makers. The authors conclude that the articulation between these theories of neighborhood dynamics and the present urban policy focus dooms recent programs, once again, to failure.     

Rurality and well-being during the middle years of life

Popular stereotypes and theorizing by social scientists suggest that rural people are more satisfied with their communities and happier with their life situations than are their nonrural counterparts. This enhanced well-being is believed to result at least partly from the presence of kinship and friendship ties in the local community and the adherence to traditional religious beliefs. Data from a panel study of nearly 1200 middle aged persons from Pennsylvania surveyed in 1971 and 1984 provided indices of community satisfaction and happiness. When income was controlled, country residents expressed slightly higher levels of community satisfaction than did town or urban dwellers in both time periods. Happiness was not related to residence location. Income was a relatively more important predictor of community satisfaction and happiness among urban than among country residents, while number of friends was relatively more important for rural residents. Number of kin living nearby and adherence to traditional religious beliefs were not related to well-being regardless of residence location.     

An exponential model of female sterility

It is suggested that a useful component of a fertility simulation would be proportions of females sterile by age. Data on this phenomenon are rather limited, but they indicate that proportional sterility may not easily be described by a simple function. We propose that rates of becoming sterile may be adequately described by an exponential function utilizing proper parameter values. Such exponential-model rates form the basis for computation of a fecundity decrement table presented in this paper. Sterility proportions from the table are compared to some empirical data.     

Gender,power, and population change

This report describes fertility and mortality trends in developing countries and discusses how gender is defined and measured in some countries. The discussion relies on case studies and country statistics to reveal how gender shapes the lives of all people in all societies. Gender is defined as the different roles women and men play in society. Gender is manifested in institutional structures, power relations, and culturally determined behavior. In no society do women and men share equal roles. The effects of inequality for women are manifested differently between countries. The 1994 International Conference on Population and Development in Cairo established the goal of gender equality. Educational enrollment and illiteracy are two measures of gender inequality that affect opportunities in society for advancement, power, and status. Girls are less likely to be enrolled in school than boys and more likely to have higher absenteeism rates. In China, absenteeism of girls is actually increasing under reforms. Marriage practices may devalue the investment in girls' education. Women experience different working conditions: they work longer hours, are paid less or not at all, and hold lower-status jobs. The exceptions are found in the Philippines and Brazil, where women hold more professional jobs than men. Women carry multiple responsibilities that consume time and prevent greater involvement in public life. Dowry and brideprice can constrain family relations. Women generally have fewer inheritance rights. Few women hold high-level public office positions or parliamentary seats. The extent to which gender inequality is reflected in demographic processes depends upon the gap in power in education, employment, and income. The relationship between gender and demographic processes is a central topic currently being researched.     

族群边缘的神话缔造:湘西的白帝天王信仰(1715-1996)

自清朝以来,湘西地区的苗人、汉人移民、汉人士兵和土家族人都普遍信仰＂白帝天王＂,白帝天王的庙宇遍布各处。然而在不同信众群体的心中,这个神灵的形象以及对它的理解很可能是不同的。尽管如此,白帝天王信仰在当地却起到了次官方政治的作用。无论信徒是谁,尽管信仰仪式的对象相同,但是神话阐释可以是多种多样的。对一个群体来说,神话解释之所以灵验,是因为它的某个版本满足了此群体的意识与需求。湘西地区不同信众群体在不同时期所缔造的关于白帝天王的故事就鲜明地呈现了此条规则。他们采用＂挪用＂与＂叙事化＂的双重手法,把借用的或原创的事件与本群体中已经存在的符号和神秘历史融合起来,再加上别处而来的口传或文本元素,然后加入与本群体相关的地点、事件和共同记忆,完成神话的本地化。在湘西这个动荡多变的社会中,对秩序和身份之另类形式的讨论,就体现在关于白帝天王的神话圈以及其中的各个叙事里。     

Internet and mobile phone text messaging intervention for college smokers

OBJECTIVE: The authors developed a smoking cessation program using mobile phone text messaging to provide tailored and stage-specific messages to college smokers. PARTICIPANTS AND METHODS: The authors recruited 31 daily smokers who desired to quit from a college campus and asked them to use an Internet and mobile phone text messaging program to quit smoking. RESULTS: Six weeks after program initiation, 45% reported abstinence with 42% abstinent based on cotinine verification. Continued smokers reported significantly reduced smoking rates and dependence. Overall, participants accepted the text messages. CONCLUSIONS: These results replicate findings from an earlier study and indicate that mobile phone text messaging is a potentially efficacious and easily disseminated method for providing cessation interventions to young adult smokers.     

Effects of Minimum Wages on Youth Employment: the Importance of Accounting for Spatial Correlation

The relationship between minimum wage increases and youth employment is investigated using county-level data and spatial econometric techniques. Results that account for spatial correlation indicate that a 10% increase in the effective minimum wage is associated with a 3.2% decrease in youth employment, a result that is 28% higher than the corresponding estimate that does not control for spatial correlation. Thus, estimates that do not take into account spatial correlation may significantly underestimate the negative effect of the minimum wage on teenage employment. Improperly controlling for factors that vary systematically over space can lead to incorrect inferences and misinform policy.