Time preference and labour migration in an OLG model with land and capital

"This paper constructs a two-country migration model in the lines of Galor (1986), in which the world population consists of individuals of two types who have different time preferences. Production uses three inputs: mobile labour, immobile capital and land. It is shown that both countries are necessarily inhabited by agents of both types and exhibit equal density of population and equal interest rate at the steady state equilibrium of the integrated economy. The steady state welfare implications of international labour migration are studied."

Population concentration in less developed countries: new evidence

Economic theory associates the increase in population concentration, i.e., the proportion of national population residing in the core economic region, with scale and agglomeration economies. Wheaton and Shishido (1981) estimated that these persist until real per capita national income reaches 5000 1985 US dollars (USD). After this point in a country's economic development, they predicted, population redistribution towards the core region will cease and the proportion of national population residing in the core region will commence to decline. The experience of developed countries (DCs) in the 1970s and 1980s broadly conformed to this pattern, albeit with exceptions. Evidence from less developed countries (LDCs) through the 1980 round of censuses led Vining (1986) to propose a weakened version of the USD 5000 rule in which this point is characterized only by a slowing of rate of population re-distribution towards the core, not by an outright reversal. This paper updates previously reported trends in population redistribution in LDCs and reports on many new countries. Taken as a whole, post-war data reinforce the need for caution of the sort expressed by Vining. While there is a weak negative correlation between the rate of net migration into the core region and per capita income, the share of population residing in the core region may continue to rise even when per capita income has grown to well beyond USD 5000.

[Ever growing regional differences in population numbers]

"The most urbanized provinces of the Netherlands are North-Holland, South-Holland and Utrecht. In these provinces, the population density (number of inhabitants per square kilometer of land) is five times that of the Northern provinces and Zeeland.... According to the Regional Population Forecasts 1994, up to 2015 all the provinces are expected to have a positive population growth. The population of the youngest province Flevoland will grow most rapidly: by about 50%. The population growth, both in relative and absolute terms, will be small in the Northern provinces and Zeeland (in the South West)." (SUMMARY IN ENG)

Urban restructuring in East-Central Europe: selected questions

"Several...arguments related to urban development in East-Central Europe are proposed in this article. Firstly, the concept of the socialist city is shown to be only partly relevant in the present context. Secondly, limited evidence is found in support of the often anticipated rapid population concentration in the national urban systems. Thirdly, major metropolitan centres in East-Central Europe are shown to be entering into competition with their counterparts in West-Central Europe."

Vintage growth and population density: an empirical investigation

"This paper tests a central prediction of vintage growth models of urban structure: that there are discontinuities in the population density function. The data set covers quarter sections in Chicago in 1980. Using such highly disaggregated data is critical because discontinuities are less likely to be found the larger is the unit of observation. Both a switching regression model and a nonparametric estimator reveal discontinuities and upward-sloping segments in the function, which supports the vintage growth model."

Population and employment densities: structure and change

"We examine spatial patterns and their changes during the 1970s for the Los Angeles region, by estimating monocentric and polycentric density functions for employment and population. Downtown Los Angeles is clearly identified as the statistical monocentric center of the region, and it is the most consistently strong center in the polycentric patterns. Polycentric models fit statistically better than monocentric models, and there was some shift in employment distribution toward a more polycentric pattern. These findings verify the existence of polycentricity in Los Angeles and demonstrate for the first time that employment and especially population follow a polycentric pattern based on exogenously defined employment centers. The results confirm that both employment and population became more dispersed during the 1970s."

Joint estimation of population density functions and the location of the central business district

"In this paper we [propose] a new procedure for estimating population density functions under conditions that the exact location of the CBD [central business district] is unknown or uncertain. As such it can also be utilized as a method for identifying the location of the CBD....[We apply] this method to cross-sectional data from Tel-Aviv-Yafo [Israel] during 1961 through 1990...."

Household epidemiology of Cryptosporidium parvum infection in an urban community in northeast Brazil

OBJECTIVE

To examine the transmission of Cryptosporidium infection in households with an identified person with cryptosporidiosis.

DESIGN

Prospective cohort study.

SETTING

An urban slum in Fortaleza, Brazil.

PARTICIPANTS

Thirty-one households with a child less than 3 years of age (index case) who was positive for Cryptosporidium parvum using acid-fast and auramine-stained stool smears.

MEASUREMENTS

Three stool samples (at 0, 2, and 6 weeks after identification of the index case) and two serum samples (0 and 6 weeks) were collected from each family member in households with an index case of Cryptosporidium infection.

RESULTS

Forty-five percent of index cases of Cryptosporidium infection were associated with persistent (> 14 days) diarrhea. Secondary cases of Cryptosporidium infection were identified either by stool examination or seroconversion in 18 (58%) of 31 households involving 30 persons, yielding an overall transmission rate of 19%. Of the 202 persons in this study with at least one serum sample available for analysis, 191 (94.6%) had evidence of antibodies (either IgM or IgG) to Cryptosporidium.

CONCLUSIONS

Cryptosporidium parvum is highly transmissible and infective in the family setting, with transmission rates similar to other highly infectious enteric pathogens such as Shigella species. These data are cause for added concern because of the rapidly increasing rate of seropositivity for human immunodeficiency virus.

Distribution and dynamics of rural population in Central Eastern Europe in the 20th century

This is an analysis of rural population trends in Central Eastern Europe during the twentieth century. The region is defined as including "Estonia, Latvia, Lithuania, the Kaliningrad District, Belarus, Ukraine, Poland, Czechoslovakia, Hungary, Rumania, Moldavia, Bulgaria and Yugoslavia....For each of them the size of rural population and its density have been evaluated, and then, the dynamics of demographic evolution described. An important part of the analysis has been the comparison of rural population to total population. On the basis of this comparison, structural changes and demographic trends have been defined. Particular attention has been paid to the processes of depopulation as well as their range and intensity in rural areas of Central Eastern Europe."

Famine, revolt, and the dynastic cycle: population dynamics in historic China

"Historians have long noticed that population declines in ancient China often coincided with dynasty changes, and that most of these declines were the result of internecine wars which, in turn, were often initiated by famine or density pressure. Since the interactions between density pressure, internecine wars, and dynasty changes cannot be explained by the traditional age-specific density-dependent population structure, we propose to use a bandit/peasant/ruler occupation-specific population model to interpret the dynamic socio-economic transitions of ancient Chinese population, and provide econometric support to our model. We also highlight the rich dynamics of the composition of human population, a factor which was often neglected in previous research on general populations."

Determinants of infant and early childhood mortality in Cameroon: the role of socioeconomic factors, housing characteristics, and immunization status

This study examines factors impinging on the survival of children in Cameroon using longitudinal data collected by the United Nations Demographic Training and Research Institute of Yaoundé, Cameroon. It deals especially with the role of socioeconomic factors (mother's education, employment, marital status, ethnicity, and household income), housing characteristics (construction materials, power source, source of water supply, extent of crowding), and immunization status on infant and child mortality. Two-state parametric and nonparametric hazards models for the risk of death at any time within the course of the study are used, with and without accounting for unmeasured heterogeneity. Overall, overcrowding has robust deleterious effects on infant and child survival. As regards the effects of socioeconomic variables, the robustness of the effects of household income and ethnic differentials are unchanged, even after controlling for unmeasured heterogeneity; the deleterious effects of marital status are also apparent, but these effects are largely explained by unmeasured covariates. The data also suggest that the protective effects of full immunization status are robust and not contaminated by confounding factors, at least in the first 16 months of life. These findings provide solid ground to support immunization programs and efforts as a means to reduce significantly infant and child mortality.

The dependence of marriage migrations in Japan on personal factors and ecological variables

"The purpose of this paper is to explain the interprefectural migrations at marriage in Japan by personal factors and ecological variables, using a multivariate statistical model called the nested logit model....The research is based on the micro data from a national survey on the life-course migration history of household heads and spouses, conducted in 1986 by the Institute of Population Problems in the Ministry of Health and Welfare...." Factors considered include partners' prefecture of residence, coresidence with parents, nativity, education, sibling status, period of marriage, income, gender, employment, and population density. (SUMMARY IN FRE)

Government size, demographic changes, and economic growth

"This paper examines the effect of government size on the growth rate of per capita output by incorporating demographic variables. Evidence from more than 86 countries suggests that the demographic variables not only affect economic growth, but also determine the size of government. Both the young and the old age dependency ratios were positively related to the size of government, while population density and population size were negatively related to the size of government. Moreover, when the demographic variables are included in the growth equations, the effect of government size on the growth rate of per capita output became insignificant rather than, as prior studies showed, significantly negative."