The study examines the sex imbalance at the marriageable ages according to ethnic group and religion, utilizing data obtained from the complete tabulations of the 1971 Census of Population in Sri Lanka. The active enforcement of Indian repatriation, commencing in 1971, played a major role in increasing net migration rates to significant levels in 1971, 1972, 1973, 1974 and 1975 and thereby reducing the island's growth rate to 1·45% and 1·71% in 1974 and 1975. These out-movements were further increased by the exodus of Sri Lanka citizens which began in 1972 and continued in the years 1973–75, presumably dominated by males aged 20–44 years. This emigration of Sri Lanka citizens is expected to continue and will aggravate further the difficulties of contracting a marriage within each ethnic and religious group. Possible demographic consequences are suggested.

Although recent historic studies have shown high rates of population turnover prior to, during and after the demographic transition, little is known about the causes and consequences of migration, particularly during late adolescence when migration rates are highest. This paper assesses the relationship (a) between socio-occupational mobility and premarital migration patterns and (b) between these measures of mobility and family formation. Linked vital data for ever-married cohorts born between 1855 and 1974 on Sanday, Orkney Islands, Scotland, provided an opportunity for evaluation of changes in (1) distance migrated between birth and marriage and (2) age at marriage in a small rural isolate characteristic of other populations undergoing modernization. Measures of socio-occupational mobility indicated a secular increase in upper social classes and in labour force participation, particularly in non-agricultural sectors of the economy. Migration distance between birth and marriage decreased over time, associated with a convergence in the pattern of spatial mobility between population subgroups. Whereas there was little relationship between age at marriage and measures of spatial and socio-occupational mobility, changes in migration were strongly influenced by opportunities which differed between social classes and between agricultural and non-agricultural sectors of the island economy.

The apparently closed societies of the New Guinea Highlands were traditionally in possession of quite large quantities of pearl shells traded from the coast. Since these constituted almost the only category of goods not produced as easily in the Highlands as the lowlands, and since they formed an appreciable component of the bride wealth, they suggest directional mating leading to an outward movement of women from the Highlands. Marriage movement in three samples of women confirms this suggestion.

It is possible to summarize our survey under the following four headings:

1. Members of different ethnic groups may react differently to comparable natural (usually complex) situations.

2. Laboratory measurements of various sensory functions of ethnic groups have often been contradictory; and even though some peripheral differences in perception are a priori probable, others may still be caused by cultural differences in cognition, memory content or motivation; these cognitive and memory differences may be best interpreted as differences in individually acquired but group characteristic reafference systems.

The aim of this study was to identify the characteristics of individuals who formed exogamic marriages in the Friuli region (north-east Italy) during the second half of the 19th century. Logistic regression models were devised to measure the influence of the determinants of exogamic marriage, taking into account not only variables related to context but also spouses' economic, social and cultural characteristics. The determinants of exogamic marriage differ for men and women, and also vary by region due to differences in geographical mobility and size of the marriage market. The majority of exogamic spouses belong to one of two categories: either older individuals, often, especially in the case of men, with a previous marriage; or the upper social classes.

I should like to discuss both the demographic and public health implications of the matters which have arisen at this meeting.

There are clearly some areas of consensus: we all agree that lactation is of fundamental importance, and that the birth interval is important, both for the health of the mother and child and with regard to fertility. Obviously, the longer the birth interval, the fewer births a woman will have during her reproductive life. A number of schemes were presented yesterday to show that in traditional societies with very long birth intervals there will be a reduced total fertility.

The fifty states of the US were compared in 1971–72 and 1974–75 with respect to percentage apparent conceptions aborted and infant mortality rates attributed to various causes. Only non-vehicle accidental deaths were consistently related to abortion. The correlation is non-linear; non-vehicle accidental deaths were especially high in states with little or no abortion. A decline in non-vehicle accidental deaths from before to after the Supreme Court decision was most pronounced in states where there were fewest abortions before the decision and where increases in abortion occurred following the decision.

In the early 1990s, psychologist Richard Lynn published papers documenting average reaction times and decision times in samples of nine-year-olds taken from across the world. After summarizing these data, Lynn interpreted his results as evidence of national and racial differences in decision time and general intelligence. Others have also interpreted Lynn's data as evidence of racial differences in decision time and intelligence. However, comparing Lynn's summaries with his original reports shows that Lynn misreported and omitted some of his own data. Once these errors are fixed the rankings of nations in Lynn's datasets are unstable across different decision time measures. This instability, as well as within-race heterogeneity and between-race overlap in decision times, implies that Lynn's reaction time data do not permit generalizations about the decision times and intelligence of people of different races.

Mortality from peptic ulcer among middle-aged Canadian males in the period 1959–63 has been analysed by marital status and social class. Adjustment for social class reduced only slightly the mortality disadvantage of single males compared with married males.

Worldwide data indicate a growing number of energy homeostasis disorders, which are especially dangerous in childhood. The distribution and growing trends of overweight and obesity in children have been widely investigated, unlike the prevalence of too-low body weight and its determinants. This study aimed to estimate the frequency of body mass deficiency in Polish rural girls and differences among four Polish regions – Choszczno and Leszno in the north-west, and Ostrów Mazowiecka and Suwałki in the north-east. Data were taken from 7764 rural girls aged 9–18 years examined in 1987, when the country was in economic crisis, and 9431 such girls examined in 2001, when the country was undergoing political transformation. The frequency of weight deficiency was estimated based on BMI by applying the international standards of Cole. An Extent of Overweight (EOW) index was used to create an Extent of Thinness (EOT) index. A significant increase in weight deficiency was found in the rural girls – from 7.5% in 1987 to 8.9% in 2001 – and an increase in the EOT index from 0.37 in 1987 to 0.43 in 2001. Analysis by area of residence demonstrated significant differentiation. In the regions in north-west Poland, mainly inhabited by non-farming families, the prevalence of weight deficiency in girls almost doubled from 1987 to 2001, probably because of the mass and long-term unemployment that resulted from the closure of state farms in 1992. In contrast, in the north-east regions, the prevalence of weight deficiency remained almost unchanged over this period, with only a slight decrease, probably because the inhabitants were mainly farm and farm/working families with better living conditions. Despite the overall increase in thinness prevalence in rural girls in Poland, different living conditions have had different biological effects.

Lateralized ultradian rhythms oscillating separately in the right and left hemispheres of the human brain can be monitored by variations in the tactile discrimination of either hand. A previous study in male German subjects has shown that the tactile error rates determined for the right and left hands oscillate with significantly different periodicities. In the present study, a group of Kenyan Maasai shepherds was tested while the subjects were leading herds on daily feeding routes. The Maasai exhibit considerable ultradian rhythms of about 2 hours in tactile error rates of either hand, but in contrast to the German subjects there is no significant difference between the right and left side. While an individual is en route, his hemispheres proceed through alternating states in matching segments of the path. Ultradian rhythms thus ‘scan’ not only the time of day but also the space, and might provide an intrinsic time-frame for neuronal processes of cognitive mapping.

In a recent paper in this Journal, I offered hypotheses on the offspring sex ratios of women infected with the parasite Toxoplasma gondii, and on the offspring sex ratios of people who are carriers of hepatitis B virus (HBV) (James, 2008). Subsequent research suggests that these hypotheses need amending. A detailed account of the amendments is given elsewhere in a specialized journal (James, 2010a). Here they are summarized.

In Matlab thana, a rural area of Bangladesh, there is a substantial deficit of males of reproductive age owing to urban migration of males who leave their families behind. These men nevertheless return to visit their families frequently. Thirty percent of the births in this area occur to families with migrant fathers: neonatal mortality rates in these families are nearly double those of families with non-migrant fathers. This high risk, in turn, interacts with educational attainment and maternal nutrition. Only those migrant families where mothers have no education or low body weight experience high neonatal mortality rates. Psychological stress during pregnancy, probably caused by fear and anxiety related to the husband's absence may in part be responsible for such differential risk of mortality during the neonatal period.

A survey of 15,324 abortion patients of the Population Services International clinics in Sydney revealed that 16·7% reported prior induced abrotion experience. Comparisons with other Australia clinics produced similar findings. World figures indicate that Australian patients have had fewer prior abortions than those in most other countries, with the exception of England, and Wales. Significant factors were age, material status, religious affiliation, reproductive history, employment status and education. Use of contraception increased after the abortion experience.

The method of decomposition is applied to evaluate the role played by fertility and changing nuptiality patterns in the number of legitimate live births in Ireland, 1962–77. In recent years there has been a demographic ‘transformation’ in Ireland with increasing proportions marrying and at younger ages than previously while the crude birth rate has remained one of the highest in Western Europe.

The analysis shows that the upward trend in births between 1962 and 1977 was due to more women marrying than in previous years and marrying at younger ages, but that age-specific birth rates have declined dramatically.

It is postulated that both the increasing nuptiality and the decreasing marital fertility have been occasioned by the increasing use of ‘artificial’ contraception in Ireland.

Three trends suggest that the reproductive function of the Canadian family is in transition. First, fertility has fallen and remained below the replacement level. Secondly, an increasing proportion of women are spending a larger part of their lives without having any children. Finally, an increasing proportion of women are having children without getting married.

Relationships were examined between sibling variables, perceptions of learning environments and aspirations for Australian adolescents from family contexts defined conjointly by human and social capital. Generally, the findings using a regression approach indicated that sibling variables continued to have significant and often complex associations with adolescents' aspirations after taking into account relationships between perceptions of learning environments and aspirations. Also, relationships between sibling variables, perceptions of learning environments and aspirations, varied for adolescents from the different family contexts.