Breast-feeding, birth interval and child mortality in Bangladesh

The 1975-76 Bangladesh Fertility Survey data show little evidence that breast-feeding is the intermediate factor through which birth intervals influence child survival in Bangladesh. Preceding birth interval, subsequent pregnancy and breast-feeding duration each have an independent influence on early mortality risk. Within a specific interval the risk of dying decreases with increase in duration of breast-feeding, and also with an increase in the time between the index birth and the next pregnancy. The death of the immediately preceding child in infancy has a significant negative effect on the survival chance of the index child at ages 1-5 months. However, death of the preceding child appears to have a significantly positive effect on the survival chance of the index child between ages 9 months and 5 years; this may be related to competition between siblings.     

The effect of socio-economic status and food availability on first birth interval in a pre-industrial human population

Individual variation in nutritional status has direct implications for fitness and thus is crucial in shaping patterns of life-history variation. Nevertheless, it is difficult to measure in natural populations, especially in humans. Here, we used longitudinal data on individual life-histories and annual crop yield variation collected from pre-industrial Finnish populations experiencing natural mortality and fertility to test the validity of first birth interval (FBI; time between marriage and first birth) as a surrogate measure of nutritional status. We evaluated whether women with different socio-economic groups differ in length of FBI, whether women of poorer socio-economic status and experiencing lower crop yields conceive slower following marriage, and whether shorter FBI is associated with higher lifetime breeding success. We found that poorer women had longer FBI and reduced probability of giving birth in months with low food availability, while the FBI of richer women was not affected by variation in food availability. Women with shorter FBI achieved higher lifetime breeding success and a faster reproductive rate. This is, to our knowledge, the first study to show a direct relationship between environmental conditions and speed of childbirth following marriage, highlighting the value of FBI as an indicator of nutritional status when direct data are lacking.     

THE DECADAL PROGRESS OF TRITERPENE SAPONINS FORM CUCURBITACEAE(1980-1992)

In this paper some of the decadal developments (1980-1992) on the Cucurbitaceous triterpenoids from different genera (Actinostemma, Bolbostemma, Cayaponia, Cucurbita, FevUlea, Gynostemma, Hemsleya, Luffa, Momordica, Neoalsomitra, Siraitia, Thiadiantha, Wilbradid) is presented. It is noticeable to discover oleane-type macrocyclic saponins, cucurbitane-type sweet glycosides, dammarane-type saponins, nor-curcurbitacin-type glucosides and baccharane-type, saponins. At the end of the paper, 83 references were listed.     

Economic inequalities in maternal health care: prenatal care and skilled birth attendance in India, 1992-2006

Background

The use of maternal health care is limited in India despite several programmatic efforts for its improvement since the late 1980''s. The use of maternal health care is typically patterned on socioeconomic and cultural contours. However, there is no clear perspective about how socioeconomic differences over time have contributed towards the use of maternal health care in India.

Methodology/Principal Findings

Using data from three rounds of National Family Health Survey (NFHS) conducted during 1992–2006, we analyse the trends and patterns in utilization of prenatal care (PNC) in first trimester with four or more antenatal care visits and skilled birth attendance (SBA) among poor and nonpoor mothers, disaggregated by area of residence in India and three contrasting provinces, namely, Uttar Pradesh, Maharashtra and Tamil Nadu. In addition, we investigate the relative contribution of public and private health facilities in meeting the demand for SBA, especially among poor mothers. We also examine the role of salient socioeconomic, demographic and cultural factors in influencing aforementioned outcomes. Bivariate analyses, concentration curve and concentration index, logistic regression and multinomial logistic regression models are used to understand the trends, patterns and predictors of the two outcome variables. Results indicate sluggish progress in utilization of PNC and SBA in India and selected provinces during 1992–2006. Enormous inequalities in utilization of PNC and SBA were observed largely to the disadvantage of the poor. Multivariate analysis suggests growing inequalities in utilization of the two outcomes across different economic groups.

Conclusions

The use of PNC and SBA remains disproportionately lower among poor mothers in India irrespective of area of residence and province. Despite several governmental efforts to increase access and coverage of delivery services to poor, it is clear that the poor (a) do not use SBA and (b) even if they had SBA, they were more likely to use the private providers.     

Factors affecting reproduction in rehabilitant female orangutans: young age at first birth and short inter-birth interval

This study investigated the reproductive parameters of free-ranging rehabilitant female orangutans. We aimed to assess the factors that influence these parameters and provide information that could assist with the management of orangutan reintroduction programs. We analyzed the birth records of free-ranging female rehabilitants at Bukit Lawang, Bukit Tigapuluh, Sepilok, Camp Leakey, Kaja Island, Sungai Wain, and Meratus and compared them with reproductive parameters reported in wild and zoo populations. Females’ ages at first birth were 10.6–14.7 years, significantly earlier than those of wild and zoo orangutans. Computed inter-birth intervals (IBIs) calculated by the Kaplan–Meier method were 65.1–90.1 months; the values for Camp Leakey and Bukit Lawang rehabilitants were significantly shorter than those reported for wild Sumatran orangutans. Infant mortality rates were 18–61%; the values for Bukit Lawang and Sepilok were significantly higher than those reported for wild Sumatran and zoo orangutans. In rehabilitants, young ages at first birth and shorter IBIs may result from the high energy intake enabled by provisioning, although the possibility exists that they reflect underestimations of age on arrival at rehabilitation centers. The observed high infant mortality rate may reflect poor mothering skills due to human rearing and/or increased disease transmission. This study demonstrates that accelerated reproductive rates (younger age at first birth and shorter IBI) are common in provisioned rehabilitant females on both Sumatra and Borneo.     

Timing of first birth and second birth spacing in Canada

In Canadian society the influence of first birth timing on the subsequent birth interval has been eroded over time, as shown by the Canadian Fertility Survey of 1984. The influence of first birth timing is significant for second births among women married during the baby boom period, but not for those married thereafter. Religiosity, marital status, and place of residence are significant factors in second birth timing in Canada.     

Fertility and population policy in two counties in China 1980-1991

A survey of women in two highly developed rural counties of China, Sichuan and Jiangsu Provinces, was carried out in late 1991, to gain information about demographic and economic change between 1980 and 1990. Three separate surveys were conducted: the first a questionnaire administered to married women aged 30-39, eliciting information about childbearing and contraception, as well as the social and economic background of the respondents; the second, focus group interviews emphasizing the motivation for childbearing. Official information about the selected villages, townships and counties was also collected. National level data in 1987 show that individual reproductive behaviour in China failed to conform to a universal, effectively implemented, population policy. They imply either a spatial range of policies, or great diversity in the demand for children, or perhaps a combination of both. Such diversity in reproductive behaviour is also found in the study area. The purpose of the analysis was to examine the diversity in reproductive behaviour and contraceptive practice, and to discover whether differentials are influenced by area, or else exist between individuals within areas. If the former, then the explanation may be found in differences in policy formulation and implementation between areas: and if the latter, to demand for children, or else differential application of policy restrictions. The main findings were that: (1) the explanation of the pattern of fertility and contraceptive use is to be found at the individual level (within locations) rather than in policy differences between administrative units; (2) the association between income and number of children is negative, as is that between income and the propensity for uniparous women to remain unsterilized. The theory that privilege may be exercised to gain concessions from birth planning cadres is therefore not supported; (3) ideal family size differentials are largely absent, showing that social (education) and economic (income, occupation) characteristics are not responsible for differences in reproductive motivations, and implying that the nature of the demand for children is very different from that in most rural areas of the Third World; (4) data on ideal family size by sex of the existing offspring indicate only a weak preference for sons. The low demand for children, and the weak son preference, may both be explained by the social acceptability of uxorilocal marriages, and of village endogamy, together with the prohibitive costs of children, and especially of sons. This partly results from the expense of education, but most mothers emphasize marriage costs. It is speculated that the circumstances responsible for the escalating costs of children in the two countries are likely to pertain in growing areas of the country, with the privatization of education and health services, the declining support of collective institutions, and the replacement of this function by kinship networks. These on-going changes imply that any policy of reproductive restriction for the purposes of population control is likely soon to meet with diminishing resistance; and it may later be rendered unnecessary in the eyes of government officials, as fulfilled reproductive intentions lead to a fertility level below replacement level.     

On the virtue of being the first born: the influence of date of birth on fitness in the mosquitofish, Gambusia affinis

We found in an earlier study that mosquitofish (Gambusia affinis and G. holbrooki) ceased reproduction in the late summer, long before the end of warm weather, stored fat, then utilized reserves to survive the winter and initiate reproduction the following spring. We hypothesized that this pattern of fat utilization was a life history adaptation that enabled the fish to acquire food resources in the autumn then allocate them to reproduction the following spring when the fitness of the young would be greater. Here we evaluate one aspect of this hypothesis by evaluating the probability of survival to maturity and fecundity of young as a function of date of birth. We placed cohorts comprising eight to ten litters of young born early‐, mid‐ or late in the reproductive season in replicate field enclosures. The entire experiment was repeated in two different years. Early‐born young had a significantly higher probability of survival to maturity but did not differ in fecundity relative to the last cohort of the season. Early‐born young also attained maturity early enough to reproduce in their year of birth while late‐born young had to overwinter before reproduction. The fitness consequences to the mother of either producing one more litter of young at the end of the season, versus instead storing fat and reproducing the following spring are not as determinate as are the effects of date of birth on offspring fitness. Females most often gain fitness by not producing one last litter and instead over‐wintering. If, however, the overwinter survival of offspring is not influenced by their size at the end of the season, then a female's fitness could be enhanced by producing one more litter late in the season. If instead the probability of overwinter survival is strongly influenced by the size of offspring at the end of the season, then our results suggest that a female gains more by deferring reproduction and storing for overwinter survival and reproduction the following spring.     

Fecundibility and social development in China: changes in the distribution of the first conception interval

Supporting evidence was generated to show that the hazard of conception in China increases with the duration of marriage in the first years of marriage, with controls for heterogeneity. The authors suggest that this positive duration dependence reflects a "honeymoon" effect for older cohorts and more rural, traditional areas and a change in social norms. Specifically, in Hebei the shape parameter was larger for older cohorts and it decreased from 1.15 in the model with Gamma mixing and from 1.09 to .95 in the mover-stayer model. This may mean that the "late honeymoon" effect has been decreasing over the past 30 years. Changes were not evident in Shanghai municipality. In the 12 models produced there was positive duration dependence in 10 of the models allowing for heterogeneity, but not all models were significant. The shortening of waiting time to first conception was concluded not to be caused by changes in the marriage age, selection biases, a decline in involuntary childlessness, data defects, or an increase in premarital conceptions. Data were obtained from the 1986 In-Depth Fertility Survey in China for Hebei and Shaanxi provinces and Shanghai municipality. Analysis was with time hazard models: the mover-stayer mixture model, where stayers are the proportion sterile in the population, and the nonparametric model. Data were stratified by place of residence and marriage date. Heterogeneity was treated as a "nuisance" parameter, which indicated unobserved biological, behavioral, and social differences between couples. The distribution of fecundability was not addressed     

The effect of birth interval on malnutrition in Bangladeshi infants and young children

This study was undertaken to investigate the independent effect of the length of birth interval on malnutrition in infants, and children aged 6-39 months. Data for this study were drawn from a post-flood survey conducted during October-December 1988 at Sirajganj of the Sirajgani district and at Gopalpur of the Tangail district in Bangladesh. The survey recorded the individual weights of 1887 children. Cross-tabulations and logistic regression procedures were applied to analyse the data. The proportion of children whose weight-for-age was below 70% (moderate-to-severely malnourished) and 60% (severely malnourished) of the NCHS median was tabulated against various durations of previous and subsequent birth intervals. The odds of being moderately or severely malnourished were computed for various birth intervals, controlling for: the number of older surviving siblings; maternal education and age; housing area (a proxy for wealth); age and sex of the index child; and the prevalence of diarrhoea in the previous 2 weeks for the index child. About one-third of infants and young children were moderately malnourished and 15% were severely malnourished. The proportion of children who were under 60% weight-for-age decreased with the increase in the length of the subsequent birth interval, maternal education and housing area. The proportion of malnourished children increased with the number of older surviving children. Children were at higher risk of malnutrition if they were female, their mothers were less educated, they had several siblings, and either previous or subsequent siblings were born within 24 months. This study indicates the potential importance of longer birth intervals in reducing malnutrition in children.     

Determinants of birth interval in a rural Mediterranean population (La Alpujarra, Spain)

The fertility pattern, in terms of birth intervals, in a rural population not practicing contraception belonging to La Alta Alpujarra Oriental (southeast Spain) is analyzed. During the first half of the 20th century, this population experienced a considerable degree of geographical and cultural isolation. Because of this population's high variability in fertility and therefore in birth intervals, the analysis was limited to a homogenous subsample of 154 families, each with at least five pregnancies. This limitation allowed us to analyze, among and within families, effects of a set of variables on the interbirth pattern, and to avoid possible problems of pseudoreplication. Information on birth date of the mother, age at marriage, children's birth date and death date, birth order, and frequency of miscarriages was collected. Our results indicate that interbirth intervals depend on an exponential effect of maternal age, especially significant after the age of 35. This effect is probably related to the biological degenerative processes of female fertility with age. A linear increase of birth intervals with birth order within families was found as well as a reduction of intervals among families experiencing an infant death. Our sample size was insufficient to detect a possible replacement behavior in the case of infant death. High natality and mortality rates, a secular decrease of natality rates, a log-normal birth interval, and family-size distributions suggest that La Alpujarra has been a natural fertility population following a demographic transition process.     

Unnatural deaths in South African platinum miners, 1992-2008

Background

The mortality rate from unnatural deaths for South Africa is nearly double the world average. Reliable data are limited by inaccurate and incomplete ascertainment of specific causes of unnatural death. This study describes trends in causes of unnatural death between 1992 and 2008 in a cohort of South African miners.

Methodology/Principal Findings

The study used routinely-collected retrospective data with cause of death determined from multiple sources including the mine''s human resources database, medical records, death registration, and autopsy. Cause-specific mortality rates and Poisson regression coefficients were calculated by calendar year and age group. The cohort included 40,043 men. One quarter of all 2937 deaths were from unnatural causes (n = 805). Causes of unnatural deaths were road traffic accidents 38% (109/100,000 py), homicides 30% (88/100,000 py), occupational injuries 17% (50/100,000 py), suicides 8% (24/100,000 py), and other accidents 6% (19/100,000 py). Rates of unnatural deaths declined by 2% (95%CI -4%,-1%) per year over the study period, driven by declining rates of road traffic and other accidents. The rate of occupational injury mortality did not change significantly over time (-2% per year, 95%CI -5%,+2%). Unnatural deaths were less frequent in this cohort of workers than in the South African population (IRR 0.89, 95%CI 0.82–0.95), particularly homicides (IRR 0.48, 95%CI 0.42–0.55).

Conclusions/Significance

Unnatural deaths were a common cause of preventable and premature death in this cohort of miners. While unnatural death rates declined between 1992 and 2008, occupational fatalities remained at a high level. Evidence-based prevention strategies to address these avoidable deaths are urgently needed.     

Plant science in forest canopies--the first 30 years of advances and challenges (1980-2010)

As an emerging subdiscipline of forest biology, canopy science has undergone a transition from observational, 'oh-wow' exploration to a more hypothesis-driven, experimental arena for rigorous field biology. Although efforts to explore forest canopies have occurred for a century, the new tools to access the treetops during the past 30 yr facilitated not only widespread exploration but also new discoveries about the complexity and global effects of this so-called 'eighth continent of the planet'. The forest canopy is the engine that fixes solar energy in carbohydrates to power interactions among forest components that, in turn, affect regional and global climate, biogeochemical cycling and ecosystem services. Climate change, biodiversity conservation, fresh water conservation, ecosystem productivity, and carbon sequestration represent important components of forest research that benefit from access to the canopy for rigorous study. Although some canopy variables can be observed or measured from the ground, vertical and horizontal variation in environmental conditions and processes within the canopy that determine canopy-atmosphere and canopy-forest floor interactions are best measured within the canopy. Canopy science has matured into a cutting-edge subset of forest research, and the treetops also serve as social and economic drivers for sustainable communities, fostering science education and ecotourism. This interdisciplinary context of forest canopy science has inspired innovative new approaches to environmental stewardship, involving diverse stakeholders.