Book Review The Fateful Hoaxing of Margaret Mead: A Historical Analysis of Her Samoan Research. Derek Freeman. Boulder,CO: Westview Press, 1999

Population and Environment -     

Blur-generated non-separable space–time models

Statistical space–time modelling has traditionally been concerned with separable covariance functions, meaning that the covariance function is a product of a purely temporal function and a purely spatial function. We draw attention to a physical dispersion model which could model phenomena such as the spread of an air pollutant. We show that this model has a non-separable covariance function. The model is well suited to a wide range of realistic problems which will be poorly fitted by separable models. The model operates successively in time: the spatial field at time t +1 is obtained by 'blurring' the field at time t and adding a spatial random field. The model is first introduced at discrete time steps, and the limit is taken as the length of the time steps goes to 0. This gives a consistent continuous model with parameters that are interpretable in continuous space and independent of sampling intervals. Under certain conditions the blurring must be a Gaussian smoothing kernel. We also show that the model is generated by a stochastic differential equation which has been studied by several researchers previously.     

Social,behavioral, and biological factors,and sex differences in mortality

Few studies have examined whether sex differences in mortality are associated with different distributions of risk factors or result from the unique relationships between risk factors and mortality for men and women. We extend previous research by systematically testing a variety of factors, including health behaviors, social ties, socioeconomic status, and biological indicators of health. We employ the National Health and Nutritional Examination Survey III Linked Mortality File and use Cox proportional hazards models to examine sex differences in adult mortality in the United States. Our findings document that social and behavioral characteristics are key factors related to the sex gap in mortality. Once we control for women’s lower levels of marriage, poverty, and exercise, the sex gap in mortality widens; and once we control for women’s greater propensity to visit with friends and relatives, attend religious services, and abstain from smoking, the sex gap in mortality narrows. Biological factors—including indicators of inflammation and cardiovascular risk—also inform sex differences in mortality. Nevertheless, persistent sex differences in mortality remain: compared with women, men have 30% to 83% higher risks of death over the follow-up period, depending on the covariates included in the model. Although the prevalence ofriskfactors differs by sex, the impact of those riskfactors on mortality is similar for men and women.     

Action following the discovery of a global association between the whole genome and adverse event risk in a clinical drug‐development programme

Observation of adverse drug reactions during drug development can cause closure of the whole programme. However, if association between the genotype and the risk of an adverse event is discovered, then it might suffice to exclude patients of certain genotypes from future recruitment. Various sequential and non‐sequential procedures are available to identify an association between the whole genome, or at least a portion of it, and the incidence of adverse events. In this paper we start with a suspected association between the genotype and the risk of an adverse event and suppose that the genetic subgroups with elevated risk can be identified. Our focus is determination of whether the patients identified as being at risk should be excluded from further studies of the drug. We propose using a utility function to determine the appropriate action, taking into account the relative costs of suffering an adverse reaction and of failing to alleviate the patient's disease. Two illustrative examples are presented, one comparing patients who suffer from an adverse event with contemporary patients who do not, and the other making use of a reference control group. We also illustrate two classification methods, LASSO and CART, for identifying patients at risk, but we stress that any appropriate classification method could be used in conjunction with the proposed utility function. Our emphasis is on determining the action to take rather than on providing definitive evidence of an association. Copyright © 2008 John Wiley & Sons, Ltd.     

Substance misuse amongst young people in non‐school settings: challenges to practitioners and policy makers

Over the past two decades the levels of substance misuse amongst children and young people have increased at a global level generally and within the UK in particular. Some school aged young people are considered to be at an increased risk to substance misuse, particularly those outside mainstream school. However, the literature on substance use by these young people remains comparatively limited. This paper explores this issue through an investigation of cannabis use trends amongst the High Risk Booster Sample of the Belfast Youth Development Study, a longitudinal study of adolescent substance use. It focuses upon the cannabis use patterns of young people excluded from school and those attending Emotional and Behavioural Difficulty units from the age of 11–16 years, groups who are historically categorised as vulnerable to substance misuse. The experience of these young people provides evidence to highlight the contemporary challenges facing policy makers and practitioners when addressing substance use and misuse use amongst these young people. Copyright © 2009 John Wiley & Sons, Ltd.     

生态工程:可持续的环保理念

每年夏天,世界很多国家都会担心泥石流的问题.要如何才能走出这样的困境?"生态工程"正为我们提供了一条改变的线索.生态工程的具体实行,简单地说就是让水能循环,让土壤能呼吸,让动植物得以安全生长、繁衍.这些看来好像教科书里的教条,要如何实践干生活中呢?     

The phoenix population: Demographic crisis and rebound in Cambodia

The study of mortality crises provides an unusual and valuable perspective on the relationship between mortality and fertility changes, a relationship that has puzzled demographers for decades. In this article, we combine nationally representative survey and demographic-surveillance system data to study fertility trends around the time of the Khmer Rouge (KR) regime, under which 25% of the Cambodian population died. We present the first quantitative evidence to date that attests to a one-third decline of fertility during this regime, followed by a substantial "baby boom" after the fall of the KR. Further analyses reveal that the fertility rebound was produced not only by a two-year marriage bubble but also by a surge in marital fertility that remained for nearly a decade above its precrisis level. Our results illustrate the potential influence of mortality on fertility, which may be more difficult to identify for more gradual mortality declines. To the extent that until recently, Cambodian fertility appears to fit natural fertility patterns, our findings also reinforce recent qualifications about the meaning of this core paradigm of demographic analysis.     

Diversity and change in Cambodian households, 1998–2006

Extant ethnographic studies suggest that the nuclear family has been the predominant living arrangement in Cambodia, and the country’s rapid socioeconomic transformation since the early 1990s may have accentuated that dominance. To examine these claims, we analyse here household structure in Cambodia between 1998 and 2006, based on data from the 1998 Census, two nationally-representative surveys (2000 and 2005), and a continuing demographic surveillance system (from 2000 on). Our analysis confirms the large prevalence of nuclear families, but not an unequivocal trend toward their increasing prevalence. First, nuclear families are less prevalent in urban than in rural areas, and nationwide, they appear to have receded slightly between 2000 and 2005. We find that increases in the prevalence of extended households correspond to periods of faster economic growth, and interpret these contrasted trends as signs of tensions during this transitional period in Cambodia. While the nuclear family may still be the cultural norm, a high degree of pragmatism is also evident in the acceptance of other living arrangements, albeit temporary, as required by economic opportunities and housing shortage in urban areas.     

Stress,Depression, and Drug Use Among Aging Mexican American Men Living in the Barrio

Residing in Mexican American barrios might place individuals at heightened risk for chronic financial and acute stress, which are associated with adverse mental health outcomes. Stressors could be exacerbated for substance users. This research explores relations between chronic financial stress, acute stress, and depressive symptomatology among aging Mexican American heroin and other drug-using men. A prospective cohort study and field-intensive outreach methodology were used to recruit 227 men for in-depth interviews. Participants were categorized into depressed and nondepressed groups based on symptomatology measured by the Center for Epidemiological Studies Depression Scale. Chronic financial stress (i.e., poverty) and acute stress (i.e., Life Events Questionnaire) associated with depressive symptomatology were tested using logistic regression. Findings suggest scores of depressive symptoms among substance users are highly related to chronic financial stress. Community-level interventions targeting chronic stressors present in the barrio could be especially salient in improving the mental health of Latino drug users.