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Seafloor methane emissions can affect Earth's climate and ocean chemistry. Vast quantities of methane formed by microbial decomposition of organic matter are locked within gas hydrate and free gas on continental slopes, particularly in large areas with high sediment accumulations such as deep-sea fans. The release of methane in slope environments has frequently been associated with dissociation of gas hydrates near the edge of the gas hydrate stability zone on the upper slope, with discharges in greater water depths less understood. Here we show, using data from the Rio Grande Cone (western South Atlantic), that the intrinsic, gravity-induced downslope collapse of thick slope sediment accumulations creates structures that serve as pathways for gas migration, unlocking methane and causing seafloor emissions via giant gas flares in the water column. The observed emissions in the study region (up to 310 Mg year-1) are three times greater than estimates for the entire US North Atlantic margin and reveal the importance of collapsing sediment accumulations for ocean carbon cycling. Similar outgassing systems on the Amazon and Niger fans suggest that gravity tectonics on passive margins is a common yet overlooked mechanism driving massive seafloor methane emissions in sediment-laden continental slopes.

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The mobilization of heavy metals in the environment due to industrial activities is of serious concern due to the toxicity of these metals in humans and other forms of life. The equilibrium adsorption isotherms of Cd(II), Pb(II) and Zn(II) ions, detoxification from waste water using unmodified and EDTA-modified maize husk have been studied. Maize husk was found to be an excellent adsorbent for the removal of these metal ions. The amount of these metal ions adsorbed increased as the initial concentration increased. Also, EDTA-modification enhanced the adsorption capacity of maize husk due to the chelating ability of ethylenediamine tetra acetic acid (EDTA). Among the three adsorption isotherms tested, Dubinin-Radushkevich isotherm gave the best fit with R² value ranging from 0.7646 to 0.9988 and an average value of 0.9321. This is followed by Freundlich and then Langmiur isotherms. The sorption process was found to be mostly a physiosorption process as seen from the apparent energy of adsorption which ranged from 1.03 KJ/mol to 12.91 KJ/mol. Therefore, this study demonstrates that maize husk which is an environmental pollutant could be used to adsorb heavy metals and achieve environmental cleanliness.

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Infant mortality remains high in Haiti, at 74 deaths per 1,000 live births. In this study, we aimed to assess infant mortality in Mirebalais and to identify the associated risk factors. We carried out a census of pregnant women in Mirebalais, at the beginning of the study, over a three-week period. Twelve researchers visited the homes of the newborns to enroll the families in the study and to collect demographic data. Further visits were scheduled for two, four, six, nine and twelve months after birth. If the child died during this time, the investigator asked the mother about all the steps taken to prevent the death of the child, and an autopsy was carried out. The survey began on July 12 1994 and ended on December 31 1995. During that time, about 2,151 pregnant women were enrolled. Seven of these women died and 16 had abortions. In total, 2,069 children were born to the enrolled women. We enrolled 515 other children after birth or following referral by health workers or midwives. We therefore followed 2,584 children. We found that 10% of the mothers were aged between 15 and 19 years, 66.3% had had one to three pregnancies and 73% were entirely uneducated. The early neonatal mortality rate was 4.64 per 1,000 live births, late neonatal mortality was 6.96 per thousand and post-neonatal mortality was 45.6 per thousand live births. Diarrhea was responsible for 60% of the deaths and acute respiratory infections for 11%, these two causes accounting for 71% of the deaths of children aged 1 to 12 months. Thus, although infant mortality has decreased it remains high in Mirebalais, largely due to diarrhea and acute respiratory infections in the post-neonatal period.

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Haiti has one of the highest rates of maternal mortality in the Caribbean. The "Three Delays" model proposes that pregnancy-related mortality is overwhelmingly due to delays in: (1) deciding to seek appropriate medical help for an obstetric emergency; (2) reaching an appropriate obstetric facility; and (3) receiving adequate care when a facility is reached. This framework was used to analyze a sample of 12 maternal deaths that occurred in a longitudinal cohort of pregnant Haitian women. Because of political upheavals in Haiti during the survey, these deaths are an underestimate of all deaths that occurred in the cohort. Family and friend interviews were used to obtain details about the medical and social circumstances surrounding each death. A delayed decision to see medical care was noted in eight of the 12 cases, whereas delays in transportation only appeared to be significant in two. Inadequate care at a medical facility was a factor in seven cases. Multiple delays were relevant in the deaths of three women. Family and friend interviews suggest that a lack of confidence in available medical options was a crucial factor in delayed or never made decisions to seek care. Expanding the coverage of existing referral networks, improving community recognition of obstetric emergencies, and improving the ability of existing medical institutions to deliver quality obstetric care, are all necessary. However, services will continue to be under-utilized if they are perceived negatively by pregnant women and their families. The current data thus suggest that improvements to Haiti's maternity care system which focus on reducing the third delay--that is, improving the quality and scope of care available at existing medical facilities--will have the greatest impact in reducing needless maternal deaths.

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This report describes findings from a national survey of pregnant women in Haiti regarding the social epidemiology of pedisyon (perdition), or "arrested pregnancy syndrome," a condition believed to be associated with infertility. Data collected on mortality of respondents' sisters were used to indirectly measure the prevalence of this culture-bound syndrome in the adult female population and to compare its distribution in urban and rural areas. Perdition appears to be a fairly common event that affects a large proportion of Haitian women. Reported cases of pedisyon were significantly higher in urban areas, which also differed from rural areas on respondent education, economic status, use of prenatal care, and fertility. No differences were found on sociodemographic, health, or fertility variables when women reporting perdition deaths were compared with women who reported other sister deaths. The utility and limitations of the proxy respondent method are discussed. Possible explanations for the higher rate of pedisyon among urban Haitian women are discussed, and suggestions are made for future research on arrested pregnancy syndrome.

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Much of the research on determinants of health service utilization has focused on economic and cognitive variables which influence preventative health behavior. Our ethnographic study of maternal perceptions of the barriers and incentives to immunization use in Haiti underscores the importance of 'hidden' social and psychological costs of utilization, such as embarrassment, fear, child care difficulties, and competing demands on maternal time. Findings from focus group interviews with mothers, individual interviews with health care providers, and observation at health posts identified five categories of maternal factors (competing priorities, low motivation, socioeconomic constraints, fears about health or social consequences, knowledge and folk beliefs) and five categories of system factors (accessibility, acceptability, availability, accommodation, affordability) which can deter immunization completion. The discussion focuses on how these factors influence maternal decision-making regarding use of preventive child health services. More attention is needed on the psychosocial costs of health behavior in developing country settings.

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There is uncertainty over whether vitamin A supplementation reduces morbidity among children with subclinical deficiency of the vitamin. Hence a double-blind, placebo-controlled trial of the effect of vitamin A supplementation on childhood morbidity was conducted among 11,124 children aged 6-83 months in the northwest of Haiti. After a random start, children were sequentially assigned by household units to receive either megadose vitamin A or placebo in three distribution cycles 4 months apart. 2 to 8 weeks after each administration of the vitamin A and placebo capsules, indicators of childhood morbidity were reassessed through interviews conducted in the homes of participating families. The vitamin A group was found to have an increased 2-week prevalence of all symptoms and signs of childhood morbidity assessed, including diarrhoea (rate ratio [RR] = 1.09, 95% confidence interval 1.05-1.14), rhinitis (RR = 1.02, 95% confidence interval 1.00-1.04), cold/flu symptoms (RR = 1.04, 95% confidence interval 1.01-1.06), cough (RR = 1.07, 95% confidence interval 1.03-1.11), and rapid breathing (RR = 1.18, 95% confidence interval 1.09-1.27). The study shows an increased 2-week prevalence of diarrhoea and the symptoms of respiratory infections after vitamin A supplementation.

PIP: In the late 1980s, 11,124 children 6-83 months old, living in the sparsely populated northwest of Haiti participated in a double-blind, placebo-controlled trial of the effect of vitamin A supplementation on child morbidity. An ophthalmic assistant and a supervising ophthalmologist examined all children 2 years old. 30 children had vitamin A deficient related corneal disease (20 with corneal xerosis and 10 with corneal ulceration, keratomalacia, and/or corneal scarring). The children received either a capsule containing 200,000 IU of vitamin A and 40.6 mg vitamin E or a capsule containing only 40.6 mg vitamin E (placebo) every 4 months. Field workers interviewed caretakers 2-8 weeks after the children received their capsules to gather data on signs and symptoms of illness. Children in the vitamin A group were more likely to have a higher prevalence of diarrhea and of respiratory infections than the placebo group (e.g., 1st cycle, 42 vs. 36% for diarrhea and 18 vs. 15% for rapid breathing, rate ratios = 1.6 and 1.19, respectively). The risk of morbidity was highest 8-17 weeks after receiving the megadose of vitamin A. These findings indicate that prevalence of diarrhea and respiratory infections increased 2 weeks after vitamin A supplementation. Mortality rates of the 2 groups were essentially the same. The mortality rate of nonparticipants was higher than that of participants (52/1000 vs. 23/1000), however, suggesting that the supplements may have had some benefit.

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The provision of simple health technologies in less developed countries has far outpaced the capabilities to evaluate their impact on health in general, and early childhood survival in particular. In rural Haiti, attempts to monitor the impact of health care delivery programmes have been frustrated by some of the same problems encountered elsewhere; ie lack of practicable yet scientifically sound methodologies that interface well with ongoing service delivery programmes. The 'preceding birth' technique, originally advanced by Brass and Macrae, holds promise as just such a method. Its practical appeal derives largely from simple data requirements. In its simplest form, the method requires only responses to a single question put to mothers at delivery regarding the survival status of her previous child. They have shown that the proportion of immediately preceding births dying before the 'index' birth date provides a good approximation of the standard life table probability of death before the second birthday. Given that in rural Haiti, as in much of the less developed world, few women deliver in clinic or hospital where such data could be systematically obtained, exploitation of the preceding birth method would require identification of a convenient and unobtrusive point of contact between questioner and mothers who have recently delivered. In Haiti, two options arose: (1) interview women at home after childbirth, and (2) interview women when they bring the 'index' child seeking vaccination or some other child survival intervention. Both of these deviate from the original technique of Brass and Macrae with respect to the timing and method of data collection, and could therefore introduce serious complications to the interpretation of trends in child mortality. To study this, we examined the effects of adapting the preceding birth method to a rural less developed country setting in Mirebalais, where since 1983 primary health care activities have been administered by MARCH (Management and Resources for Community Health), a private voluntary health organization. The Mirebalais study used a pregnancy register, originally developed for targeting of services, to identify women who were expected to have given birth during the 12-month period before each of two survey rounds. Brief interviews with these women would provide direct life table estimates of child mortality level and trend with which to compare estimates produced from use of the preceding birth method in modified form. Direct estimates of the probability of dying before the second birthday were 138/1000 from first round data and 134/1000 from second round data, indicating a 3% decline.(ABSTRACT TRUNCATED AT 400 WORDS)

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A rapid ethnographic assessment of barriers to health service utilization was conducted to identify maternal factors predicting use of child immunizations in Haiti. Methods included four focus group interviews, four natural group interviews, individual interviews with 14 health care providers and participant observation at vaccination posts. Analysis of qualitative data identified five categories of maternal factors associated with immunization use: competing priorities, low motivation, socioeconomic constraints, perceived accessibility of services, fears about health or social consequences and knowledge and folk beliefs related to vaccines. Selected variables among these factors were incorporated into a survey instrument designed to compare mothers of completely vaccinated children (cases) with mothers of incompletely vaccinated children (controls). The questionnaire was administered to 299 randomly selected mothers (217 cases, 82 controls). Bivariate and multivariate analyses found that of the factors identified through ethnographic research, only vaccine-related knowledge was significantly associated with immunization status. The utility and constraints of using ethnographic research for instrument development in epidemiological studies are discussed.

PIP: A rapid ethnographic assessment consisting of 4 focus groups, 4 natural group interviews, 14 provider interviews and participant observation rally posts was combined into a questionnaire which was tested by chi square for use in predicting which Haitian mothers utilize immunization services. The study population were mothers of 1800 children 12-23 months old in the Mirebalais Area Community Health program in the central highlands of Haiti. The program uses the rally post system, with teams visiting villages at 6-week intervals. Audio tapes and written notes were reduced to lists of all possible barriers to maternal utilization, and then regrouped into 16 categories, under 5 topics: competing priorities, lack of motivation, socioeconomic constraints, perceived accessibility of posts, fears of health consequences and knowledge of folk beliefs about vaccines. 22 questionnaire items were then developed, which were edited by the overall project director without input from the ethnographer. The questions were administered to 299 mothers, 82 with incompletely immunized, and 217 with completely immunized children. The questions which significantly predicted complete vaccination by bivariate analysis were knowledge of the name of 1 or more vaccines or illnesses, the recommended number of doses, and the correct age to begin vaccinations. It was likely that time demands from subsistence farming and income generating activities also affected service utilization, but the women probably interpreted the question on employment incorrectly.

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