Two opposing hypotheses were proposed to explain the lifecourse pattern in the effect of education on mortality: "cumulative advantage," where the education effect becomes stronger with age, and "age-as-leveler," where the effect becomes weaker in old age. Most empirical studies bring evidence for the latter hypothesis but the observed convergence of mortality patterns could be an artifact of selective mortality due to unobserved heterogeneity. A simulation shows that unobserved heterogeneity can bias the estimated effect of education downward so that the cohort-average effect of education decreases in old age regardless of the shape of the underlying subject-specific trajectory.

"This paper develops a multi-dimensional model for projecting households and population. The model is constructed to ensure consistency between the demographic events occurring to males and females as well as to parents and children. The model permits projection of characteristics of households, their members, and population structure, using data that are usually available from conventional sources. Unlike the traditional headship-rate method, our model can closely link the projected households with demographic rates. The model includes both nuclear and three-generation households, so that it can be used for countries where nuclear households are dominant and for countries where nuclear and three-generation households are both important. The illustrative application to China, although brief, provides some policy-relevant information about future trends of Chinese household size, structure, and the age and sex distribution of the population, with a focus on the elderly."

"This paper develops a forward demographic rates-based multiregional population model on the basis of a set of multiregional population accounts. Forward emigration rates and immigration flows are adopted to describe the external migrations. The model is used to make consistent multiregional population projections of China at a provincial level.... Three sets of multiregional population projections of China at provincial level are made for the period 1987-2087. It is found that the national population trend is a combination of various regional population trends. Some regions, such as Zhejiang, will reach their population peak as early as the beginning of the next century while other regions, such as Xinjiang, will face continuous population growth in the first half of the next century."

Stem and precursor cells play a critical role in tissue development, maintenance, and repair throughout the life. Often, experimental limitations prevent direct observation of the stem cell compartment, thereby posing substantial challenges to the analysis of such cellular systems. Two-type age-dependent branching processes with immigration are proposed to model populations of progenitor cells and their differentiated progenies. Immigration of cells into the pool of progenitor cells is formulated as a non-homogeneous Poisson process. The asymptotic behavior of the process is governed by the largest of two Malthusian parameters associated with embedded Bellman-Harris processes. Asymptotic approximations to the expectations of the total cell counts are improved by Markov compensators.

The infectious agent of many neurodegenerative disorders is thought to be aggregates of prion protein, which are transmitted between cells. Recent work in yeast supports this hypothesis, but suggests that only aggregates below a critical size are transmitted efficiently. The total number of transmissible aggregates in a typical cell is a key determinant of strain infectivity. In a discrete-time branching process model of a yeast colony with prions, prion aggregates increase in size according to a Poisson process and only aggregates below a threshold size are transmitted during cell division. The total number of cells with aggregates in a growing population of yeast is expressed.

How far do Americans live from their close and extended kin? The answer is likely to structure the types of social, instrumental, and financial support that they are able to provide to one another. Based on the Panel Study of Income Dynamics, kin pairs vary widely in odds of household co-residence, co-residence in the same administrative units, and inter-tract distances if they do not live in the same census tract. Multivariate regression tests show that family structure, educational attainment, and age are closely associated with kin proximity. Fixed effects models demonstrate that fam ily formation shapes spatial relations between kin.

A spatial multiple membership model formalizes the effect of neighborhood affluence on antenatal smoking. The data are geocoded New Jersey birth certificate records linked to United States census tract-level data from 1999 to 2007. Neighborhood affluence shows significant spatial autocorrelation and local clustering. Better model fit is observed when incorporating the spatial clustering of neighborhood affluence into multivariate analyses. Relative to the spatial multiple membership model, the multilevel model that ignores spatial clustering produced downwardly biased standard errors; the effective sample size of the key parameter of interest (neighborhood affluence) is also lower. Residents of communities located in high-high affluence clusters likely have better access to health-promoting institutions that regulate antenatal smoking behaviors.

"This paper uses a two-level nested logit model to explain the inter-stratum (city, town and rural county) and interprovincial migration behaviors of the young adults (aged 17-29) in China during a three-year period (1985-87), based on the micro data of the 1987 National Population Survey. The migration propensity of each person is represented by a departure probability and a destination choice probability. These probabilities are then expressed as functions of personal factors and place attributes. The main findings are that personal factors are of paramount importance in explaining the departure behaviors, and that both departure and destination behaviors responded to market forces in a sensible way, despite government control on territorial movements."

"This paper aims to construct a demographic microsimulation model, which is easily applicable to gene transmission..., and to examine the distribution of completed parity as a fertility measure at a population level according to the schedule of individual life course....The simulation model was applied to the data of the Gidra-speaking people living in the lowlands of Papua New Guinea."

Nationally representative survey data and small-area estimation techniques are used to assess geographic prevalence of left-handedness in China 2011. Measures of individuals' handedness are self-reported dominant hand and hand grip strength, yielding four estimates of left-handed prevalence at the provincial level. These estimates concord with one another. There are several geographic clusters of high-prevalence rates of left-handers located in ethnic minority-designated autonomous areas or historically revolutionary base areas, which may reflect a deep-rooted sense of defiance to authorities and promote such cultural values as individual autonomy and equality among local people.