Do female association preferences predict the likelihood of reproduction?

Sexual selection acting on male traits through female mate choice is commonly inferred from female association preferences in dichotomous mate choice experiments. However, there are surprisingly few empirical demonstrations that such association preferences predict the likelihood of females reproducing with a particular male. This information is essential to confirm association preferences as good predictors of mate choice. We used green swordtails (<i>Xiphophorus helleri</i>) to test whether association preferences predict the likelihood of a female reproducing with a male. Females were tested for a preference for long- or short-sworded males in a standard dichotomous choice experiment and then allowed free access to either their preferred or non-preferred male. If females subsequently failed to produce fry, they were provided a second unfamiliar male with similar sword length to the first male. Females were more likely to reproduce with preferred than non-preferred males, but for those that reproduced, neither the status (preferred/non-preferred) nor the sword length (long/short) of the male had an effect on brood size or relative investment in growth by the female. There was no overall preference based on sword length in this study, but male sword length did affect likelihood of reproduction, with females more likely to reproduce with long- than short-sworded males (independent of preference for such males in earlier choice tests). These results suggest that female association preferences are good indicators of female mate choice but that ornament characteristics of the male are also important

Birth spacing and child mortality: an analysis of prospective data from the Nairobi urban health and demographic surveillance system.

The majority of studies of the birth spacing-child survival relationship rely on retrospective data, which are vulnerable to errors that might bias results. The relationship is re-assessed using prospective data on 13,502 children born in two Nairobi slums between 2003 and 2009. Nearly 48% were first births. Among the remainder, short preceding intervals are common: 20% of second and higher order births were delivered within 24 months of an elder sibling, including 9% with a very short preceding interval of less than 18 months. After adjustment for potential confounders, the length of the preceding birth interval is a major determinant of infant and early childhood mortality. In infancy, a preceding birth interval of less than 18 months is associated with a two-fold increase in mortality risks (compared with lengthened intervals of 36 months or longer), while an interval of 18-23 months is associated with an increase of 18%. During the early childhood period, children born within 18 months of an elder sibling are more than twice as likely to die as those born after an interval of 36 months or more. Only 592 children experienced the birth of a younger sibling within 20 months; their second-year mortality was about twice as high as that of other children. These results support the findings based on retrospective data

Health inequalities in the older population: the role of personal capital, social resources and socio-economic circumstances.

Older people now constitute the majority of those with health problems in developed countries so an understanding of health variations in later life is increasingly important. In this paper, we use data from three rounds of the Health Survey for England, a large nationally representative sample, to analyse variations in the health of adults aged 65-84 by indicators of attributes acquired in childhood and young adulthood, termed personal capital; and by current social resources and current socio-economic circumstances, while controlling for smoking behaviour and age. We used six indicators of health status in the analysis, four based on self-reports and two based on nurse collected data, which we hypothesised would identify different dimensions of health. Results showed that socio-economic indicators, particularly receipt of income support (a marker of poverty) were most consistently associated with raised odds of poor health outcomes. Associations between marital status and health were in some cases not in the expected direction. This may reflect bias arising from exclusion of the institutional population (although among those under 85 the proportion in institutions is very low) but merits further investigation, especially as the marital status composition of the older population is changing. Analysis of deviance showed that social resources (marital status and social support) had the greatest effect on the indicator of psychological health (GHQ) and also contributed significantly to variation in self-rated health, but among women not to variation in taking three or more medicines and among men not to self-reported long-standing illnesses. Smoking, in contrast, was much more strongly associated with these indicators than with self-rated health. These results are consistent with the view that self-rated health may provide a holistic indicator of health in the sense of well-being, whereas measures such as taking prescribed medications may be more indicative of specific morbidities. The results emphasise again the need to consider both socio-economic and socio-psychological influences on later life health

Levels and Correlates of Non-Adherence to WHO Recommended Inter-Birth Intervals in Rufiji, Tanzania.

Poorly spaced pregnancies have been documented worldwide to result in adverse maternal and child health outcomes. The World Health Organization (WHO) recommends a minimum inter-birth interval of 33 months between two consecutive live births in order to reduce the risk of adverse maternal and child health outcomes. However, birth spacing practices in many developing countries, including Tanzania, remain scantly addressed. METHODS: Longitudinal data collected in the Rufiji Health and Demographic Surveillance System (HDSS) from January 1999 to December 2010 were analyzed to investigate birth spacing practices among women of childbearing age. The outcome variable, non-adherence to the minimum inter-birth interval, constituted all inter-birth intervals <33 months long. Inter-birth intervals >=33 months long were considered to be adherent to the recommendation. Chi-Square was used as a test of association between non-adherence and each of the explanatory variables. Factors affecting non-adherence were identified using a multilevel logistic model. Data analysis was conducted using STATA (11) statistical software. RESULTS: A total of 15,373 inter-birth intervals were recorded from 8,980 women aged 15--49 years in Rufiji district over the follow-up period of 11 years. The median inter-birth interval was 33.4 months. Of the 15,373 inter-birth intervals, 48.4% were below the WHO recommended minimum length of 33 months between two live births. Non-adherence was associated with younger maternal age, low maternal education, multiple births of the preceding pregnancy, non-health facility delivery of the preceding birth, being an in-migrant resident, multi-parity and being married. CONCLUSION: Generally, one in every two inter-birth intervals among 15--49 year-old women in Rufiji district is poorly spaced, with significant variations by socio-demographic and behavioral characteristics of mothers and newborns. Maternal, newborn and child health services should be improved with a special emphasis on community- and health facility-based optimum birth spacing education in order to enhance health outcomes of mothers and their babies, especially in rural settings

Multidimensional Nature of Undernutrition: A Statistical Approach

The statistical assessment of undernutrition is usually restricted to a pairwise analysis of anthropometric indicators. The main objective of this study was to model the associations between underweight, stunting and wasting and to check whether multidimensionality of undernutrition can be justified from a purely statistical point of view. 3742 children aged 0 to 59 months were enrolled in a cross-sectional household survey (2004 Cameroon Demographic and Health Surveys (DHS)). The saturated loglinear model and the multiple correspondence analysis (MCA) showed no interaction and a highly significant association between underweight and stunting (P=0), underweight and wasting (P=0); but not between stunting and wasting (P=0.430). Cronbach's alpha coefficient between weight-for-age, height-for-age and weight-for-height was 0.62 (95% CI 0.59, 0.64). Thus, the study of these associations is not straightforward as it would appear in a first instance. The lack of three-factor interaction and the value of the Cronbach's alpha coefficient indicate that undernutrition is indeed (statistically) multidimensional. The three indicators are not statistically redundant; thus for the case of Cameroon the choice of a particular anthropometric indicator should depend on the goal of the policy maker, as it comes out of this study that no single indicator is to be used for all situations.Stunting; Wasting; Underweight; anthropometric measures; Z-score; Loglinear models

The use of Human Subjects in Biomedical Research: A Problematic Scientific Past Shapes Present Ethical Challenges

The ethics of human experimentation is a relatively new phenomenon in medicine. The Nuremberg Code and the Helsinki Declaration focused on informed consent in human experimentation. More recently, ethicists have begun to emphasize that, beyond the need for consent, the \"content\" of the experiment also needs to be ethical. The method and process of the experiment must be humanizing and affirming of the subject as moral agent. The religious perspective has provided a comprehensive moral foundation, demanding respect for the subjects\' moral agency and their right to he treated as equally worthy members of the human community, thus ensuring the integrity of the subject as person

Determinants of Neonatal and Post-neonatal Mortality in Pakistan

Ensuring the survival and well being of children is a concern of families, communities and nations throughout the world. Since the turn of the 20th century infant and child mortality in more developed countries has steadily declined and, currently, has been reduced to almost minimal levels. In contrast, although infant and child mortality has declined in the past three decades in most less developed countries, the pace of change and the magnitude of improvement vary considerably from one country to another. The inverse relationship between socio-economic variables of the parents and infant and child mortality is well established by several studies [Muhuri (1995); Forste (1994); Hobcraft, et al. (1984); Caldwell (1979); Sathar (1985, 1987)] and it holds true irrespective of the overall level of mortality in the national populations [Ruzicka (1989)]. The influence of parental education on infant and child health and mortality has proved to be universally significant [Bicego and Boerma (1993); Caldwell, et al. (1990)]. The father’s education, mother’s education and their work status each have independent effects upon child survival in developing countries [Sandiford, et al. (1995); Forste (1994); Caldwell, et al. (1983)]. Economic conditions of the household also help in explaining the variation in infant and child mortality. The nature of housing, diet, access to and availability of water and sanitary conditions as well as medical attention all depend on the economic conditions of the household. For example, poor families may reside in crowded, unhygienic housing and, thus, suffer from infectious disease associated with inadequate and contaminated water supplies and with poor sanitation [Esrey and Habicht (1986)]. Maternal factors, which are biological attributes of birth, such as the age of mother at the time of childbirth, birth order and birth interval [Forste (1994); Rutstein (1984)], have significant effects on child survival.

Education or wealth: which matters more for reducing child mortality in developing countries?

This article systematically addresses mother’s education as a fundamental determinant of child mortality in developing countries. The main proposition is that setting the right policy priorities in developing countries requires distinguishing between the role of education and that of material resources in influencing child survival. Despite a tendency to regard both education and economic resources as interchangeable indicators of socioeconomic status, determining their relative importance with respect to child health is important because policies for enhancing one or the other can be quite different. We begin with a comprehensive review of the literature addressing the different causal mechanisms through which maternal education impacts on the health of her offspring. We include better maternal health, increased health-specific knowledge, adoption of non-traditional behaviours, and general female empowerment in addition to the effects of greater economic resources gained as a consequence of education. We use recent Demographic and Health Survey (DHS) data for developing countries and examine the associations between survival of the youngest child over the first year of life, the mother’s educational attainment and the DHS indicator of household wealth both descriptively and using multivariate models. The results show that in the vast majority of countries and under virtually all models mother’s education matters more for infant survival than household wealth. Our findings challenge frequently held views and suggest a reorientation of global health policies to more directly address increasing female education as a primary policy option for improving child health.