13 research outputs found

    Long Term Two-Phase Flow Analysis of the Deep Low Permeability Rock at the Bruce DGR Site

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    Abnormal pressures have been measured in the deep boreholes at the Bruce site, southern Ontario, where a deep geologic repository for low and intermediate level radioactive waste disposal has been proposed. The pressure regime in the stratigraphic units exhibits either higher than hydrostatic pressure (over-pressured) or lower than hydrostatic pressure (under-pressured) are considered to be abnormal. At the Bruce site, the Ordovician sediments are under-pressured while the underlying Cambrian sandstone and the overlying Guelph carbonate are over-pressured. Hypotheses have been documented in literature to explain the phenomenon of abnormal pressures. These hypotheses include osmosis, glacial loading and deglaciation unloading, exhumation of overlying sediments, crustal flexure and the presence of an immiscible gas phase. Previous work on the Bruce site has shown that the under-pressures in the Ordovician limestone and shales could not be explained by glaciation and deglaciation or by saturated analyses. The presence of a gas phase in the Ordovician formations has been determined to be a reasonable cause of the under-pressure developed in the Ordovician shales and limestones at the Bruce site. Support for the presence of a gas phase includes solution concentrations of methane, concentrations of environmental isotopes related to methane and estimates of water and gas saturations from laboratory core analyses. The primary contribution of this thesis is the sensitivity analyses performed on the hydrogeologic parameters with respect to a one dimensional two-phase flow model. First, a one dimensional two-phase air and water flow model was adopted and reconstructed to simulate the long-term evolution of the groundwater regimes at the DGR site. Then the hydrogeologic parameters which impact the presence of under-pressure in the groundwater are investigated. Data required to quantify the properties of geologic media and groundwater are adopted directly from borehole testing and laboratory testing results. The permeable boundaries of the domain are assumed to be water saturated and pressure specified (using hydrostatic conditions in the Guelph Formation and hydrostatic with 120 m over-pressure condition in the Cambrian and Precambrian). Isothermal conditions were assumed, thus constant water density and viscosity values are estimated for the average total dissolved solids (TDS) concentration of the modelled stratigraphic column. A constant diffusion coefficient (a diffusivity of 0.25×1080.25\times10^{-8} m2^2/s) of air in water is assumed with a saturation-dependent tortuosity. The air generation rate is assumed to simulate the gas phase generated in the Ordovician formations. The numerical simulation of up to 4 million years provides a means to explore the behaviour of gas phase dissipation due to partitioning into the water phase and diffusive transport in the solute phase. Results confirmed that the presence of a gas phase would result in the under-pressure in water

    Efficacy of early neonatal vitamin A supplementation in reducing mortality during infancy in Ghana, India and Tanzania: study protocol for a randomized controlled trial

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    Vitamin A supplementation of 6-59 month old children is currently recommended by the World Health Organization based on evidence that it reduces mortality. There has been considerable interest in determining the benefits of neonatal vitamin A supplementation, but the results of existing trials are conflicting. A technical consultation convened by WHO pointed to the need for larger scale studies in Asia and Africa to inform global policy on the use of neonatal vitamin A supplementation. Three trials were therefore initiated in Ghana, India and Tanzania to determine if vitamin A supplementation (50,000 IU) given to neonates once orally on the day of birth or within the next two days will reduce mortality in the period from supplementation to 6 months of age compared to placebo. The trials are individually randomized, double masked, and placebo controlled. The required sample size is 40,200 in India and 32,000 each in Ghana and Tanzania. The study participants are neonates who fulfil age eligibility, whose families are likely to stay in the study area for the next 6 months, who are able to feed orally, and whose parent(s) provide informed written consent to participate in the study. Neonates randomized to the intervention group receive 50,000 IU vitamin A and the ones randomized to the control group receive placebo at the time of enrollment. Mortality and morbidity information are collected through periodic home visits by a study worker during infancy. The primary outcome of the study is mortality from supplementation to 6 months of age. The secondary outcome of the study is mortality from supplementation to 12 months of age. The three studies will be analysed independent of each other. Subgroup analysis will be carried out to determine the effect by birth weight, sex, and timing of DTP vaccine, socioeconomic groups and maternal large-dose vitamin A supplementation. The three ongoing studies are the largest studies evaluating the efficacy of vitamin A supplementation to neonates. Policy formulation will be based on the results of efficacy of the intervention from the ongoing randomized controlled trials combined with results of previous studies

    Population-based rates, timing and causes of maternal deaths, stillbirths, and neonatal deaths in south Asia and sub-Saharan Africa: a multi-country prospective cohort study

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    BackgroundModelled mortality estimates have been useful for health programmes in low-income and middle-income countries. However, these estimates are often based on sparse and low-quality data. We aimed to generate high quality data about the burden, timing, and causes of maternal deaths, stillbirths, and neonatal deaths in south Asia and sub-Saharan Africa.MethodsIn this prospective cohort study done in 11 community-based research sites in south Asia and sub-Saharan Africa, between July, 2012, and February, 2016, we conducted population-based surveillance of women of reproductive age (15–49 years) to identify pregnancies, which were followed up to birth and 42 days post partum. We used standard operating procedures, data collection instruments, training, and standardisation to harmonise study implementation across sites. Verbal autopsies were done for deaths of all women of reproductive age, neonatal deaths, and stillbirths. Physicians used standardised methods for cause of death assignment. Site-specific rates and proportions were pooled at the regional level using a meta-analysis approach.FindingsWe identified 278 186 pregnancies and 263 563 births across the study sites, with outcomes ascertained for 269 630 (96·9%) pregnancies, including 8761 (3·2%) that ended in miscarriage or abortion. Maternal mortality ratios in sub-Saharan Africa (351 per 100 000 livebirths, 95% CI 168–732) were similar to those in south Asia (336 per 100 000 livebirths, 247–458), with far greater variability within sites in sub-Saharan Africa. Stillbirth and neonatal mortality rates were approximately two times higher in sites in south Asia than in sub-Saharan Africa (stillbirths: 35·1 per 1000 births, 95% CI 28·5–43·1 vs 17·1 per 1000 births, 12·5–25·8; neonatal mortality: 43·0 per 1000 livebirths, 39·0–47·3 vs 20·1 per 1000 livebirths, 14·6–27·6). 40–45% of pregnancy-related deaths, stillbirths, and neonatal deaths occurred during labour, delivery, and the 24 h postpartum period in both regions. Obstetric haemorrhage, non-obstetric complications, hypertensive disorders of pregnancy, and pregnancy-related infections accounted for more than three-quarters of maternal deaths and stillbirths. The most common causes of neonatal deaths were perinatal asphyxia (40%, 95% CI 39–42, in south Asia; 34%, 32–36, in sub-Saharan Africa) and severe neonatal infections (35%, 34–36, in south Asia; 37%, 34–39 in sub-Saharan Africa), followed by complications of preterm birth (19%, 18–20, in south Asia; 24%, 22–26 in sub-Saharan Africa).InterpretationThese results will contribute to improved global estimates of rates, timing, and causes of maternal and newborn deaths and stillbirths. Our findings imply that programmes in sub-Saharan Africa and south Asia need to further intensify their efforts to reduce mortality rates, which continue to be high. The focus on improving the quality of maternal intrapartum care and immediate newborn care must be further enhanced. Efforts to address perinatal asphyxia and newborn infections, as well as preterm birth, are critical to achieving survival goals in the Sustainable Development Goals era

    Effectiveness of zinc supplementation plus oral rehydration salts compared with oral rehydration salts alone as a treatment for acute diarrhea in a primary care setting: a cluster randomized trial

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    Background: The purpose of this work was to evaluate whether education about zinc supplements and provision of zinc supplements to caregivers is effective in the treatment of acute diarrhea and whether this strategy adversely affects the use of oral rehydration salts. Patients and Methods: Six clusters of 30,000 people each in Haryana, India, were randomly assigned to intervention and control sites. Government and private providers and village health workers were trained to prescribe zinc and oral rehydration salts for use in diarrheal episodes in 1-month-old to 5-year-old children in intervention communities; in the control sites, oral rehydration salts alone was promoted. In 2 cross-sectional surveys commencing 3 months (survey 2) and 6 months (survey 3) after the start of the intervention, care-seeking behavior, drug therapy, and oral rehydration salts use during diarrhea, diarrheal and respiratory morbidity, and hospitalization rates were measured. Results: In the 2 surveys, zinc was used in 36.5% (n = 1571) and 59.8% (n = 1649) and oral rehydration salts in 34.8% (n = 1571) and 59.2% (n = 1649) of diarrheal episodes occurring in the 4 weeks preceding interviews in the intervention areas. In control areas, oral rehydration salts were used in 7.8% (n = 2209) and 9.8% (n = 2609) of episodes. In the intervention communities, care seeking for diarrhea reduced by 34% (survey 3), as did the prescription of drugs of unknown identity (survey 3) and antibiotics (survey 3) for diarrhea. The 24-hour prevalences of diarrhea and acute lower respiratory infections were lower in the intervention communities (survey 3). All-cause, diarrhea, and pneumonia hospitalizations in the preceding 3 months were reduced in the intervention compared with control areas (survey 3). Conclusions: Diarrhea is more effectively treated when caregivers receive education on zinc supplementation and have ready access to supplies of oral rehydration salts and zinc, and this approach does not adversely affect the use of oral rehydration salts; in fact, it greatly increases use of the same

    Efficacy of early neonatal supplementation with vitamin A to reduce mortality in infancy in Haryana, India (Neovita): a randomised, double-blind, placebo-controlled trial

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    Background: Vitamin A supplementation in children aged 6 months to 5 years has been shown to reduce mortality. The efficacy of neonatal supplementation with vitamin A to reduce mortality in the first 6 months of life is plausible but not established. We aimed to assess the efficacy of neonatal oral supplementation with vitamin A to reduce mortality between supplementation and 6 months of age. Methods: We undertook an individually randomised, double-blind, placebo-controlled trial in Haryana, India. We identified pregnant women through a surveillance programme undertaken every 3 months of all female residents in two districts of Haryana, India, aged 15–49 years, and screened every identified livebirth. Eligible participants were neonates whose parents consented to participate, were likely to stay in the study area until at least 6 months of age, and were able to feed orally at the time of enrolment. Participants were randomly assigned to receive oral capsules containing vitamin A (retinol palmitate 50 000 IU plus vitamin E 9·5–12·6 IU) or placebo (vitamin E 9·5–12·6 IU) within 72 h of birth. Randomisation was in blocks of 20 according to a randomisation list prepared by a statistician not otherwise involved with the trial. Investigators, participants' families, and the data analysis team were masked to treatment allocation. The primary outcome was mortality between supplementation and 6 months of age. Analysis included all participants assigned to study groups. This trial is registered with ClinicalTrials.gov, number NCT01138449, and the Indian Council of Medical Research Clinical Trial Registry, number CTRI/2010/091/000220. Findings: Between June 24, 2010, and July 1, 2012 we screened 47 777 neonates and randomly assigned 44 984 to receive vitamin A (22 493) or placebo (22 491). Between supplementation and 6 months of age, 656 infants died in the vitamin A group compared with 726 in the placebo group (29·2 per 1000 vs 32·3 per 1000; difference −3·1 per 1000, 95% CI −6·3 to 0·1; risk ratio 0·90, 95% CI 0·81 to 1·00). We noted no significant interactions between the intervention effect and sex on mortality at 6 months (p=0·409). Supplementation with 50 000 IU vitamin A within the first 72 h of life was generally safe and well tolerated, with the exception of a small excess risk of transient bulging fontanelle (205 cases in the vitamin A group confirmed by physician vs 80 cases in the placebo group, risk ratio 2·56 [95% CI 1·98–3·32]). Interpretation: The findings of this study, done in a population in which vitamin A deficiency is a moderate public health problem, are consistent with a modest reduction in mortality between supplementation and 6 months of age. These findings must be viewed together with similar trials in other populations to enable determination of appropriate public health policy

    Community initiated kangaroo mother care and early child development in low birth weight infants in India - a randomized controlled trial

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    Background: In a randomized controlled trial (RCT) with 8402 stable low birthweight (LBW) infants, majority being late preterm or term small for gestational age, community-initiated KMC (ciKMC) showed a significant improvement in survival. However, the effect of ciKMC on neurodevelopment is unclear. This is important to elucidate as children born with low birth weight are at high risk of neurodevelopmental deficits. In the first 552 stable LBW infants enrolled in the above trial, we evaluated the effect of ciKMC on neurodevelopmental outcomes during infancy. Method: This RCT was conducted among 552 stable LBW infants, majorly late preterm or term small for gestational age infants without any problems at birth and weighing 1500–2250 g at birth. The intervention comprised of promotion of skin-to-skin contact and exclusive breastfeeding by trained intervention delivery team through home visits. The intervention group mother-infant-dyads were supported to practice ciKMC till day 28 after birth or until the baby wriggled-out. All infants in the intervention and control groups received Home Based Post Natal Care (HBPNC) visits by government health workers. Cognitive, language, motor and socio-emotional outcomes were assessed at infant-ages 6- and 12-months using Bayley Scale of Infant Development (BSID-III). Other outcomes measured were infant temperament, maternal depression, maternal sense of competence, mother-infant bonding and home-environment. We performed post-hoc equivalence testing using two one-sided tests of equivalence (TOST) to provide evidence that ciKMC does not do harm in terms of neurodevelopment. Results: In the intervention arm, the median (IQR) time to initiate ciKMC was 48 (48 to 72) hours after birth. The mean (SD) duration of skin-to-skin-contact was 27.9 (3.9) days with a mean (SD) of 8.7 (3.5) hours per day. We did not find significant effect of ciKMC on any of the child developmental outcomes during infancy. The TOST analysis demonstrated that composite scores for cognitive, language and motor domains at 12 months among the study arms were statistically equivalent. Conclusion: Our study was unable to capture any effect of ciKMC on neurodevelopment during infancy in this sample of stable late preterm or term small for gestational age infants. Long term follow-up may provide meaningful insights

    Population-based rates, timing, and causes of maternal deaths, stillbirths, and neonatal deaths in south Asia and sub-Saharan Africa: a multi-country prospective cohort study

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    © 2018 This is an Open Access article published under the CC BY 3.0 IGO license Background: Modelled mortality estimates have been useful for health programmes in low-income and middle-income countries. However, these estimates are often based on sparse and low-quality data. We aimed to generate high quality data about the burden, timing, and causes of maternal deaths, stillbirths, and neonatal deaths in south Asia and sub-Saharan Africa. Methods: In this prospective cohort study done in 11 community-based research sites in south Asia and sub-Saharan Africa, between July, 2012, and February, 2016, we conducted population-based surveillance of women of reproductive age (15–49 years) to identify pregnancies, which were followed up to birth and 42 days post partum. We used standard operating procedures, data collection instruments, training, and standardisation to harmonise study implementation across sites. Verbal autopsies were done for deaths of all women of reproductive age, neonatal deaths, and stillbirths. Physicians used standardised methods for cause of death assignment. Site-specific rates and proportions were pooled at the regional level using a meta-analysis approach. Findings: We identified 278 186 pregnancies and 263 563 births across the study sites, with outcomes ascertained for 269 630 (96·9%) pregnancies, including 8761 (3·2%) that ended in miscarriage or abortion. Maternal mortality ratios in sub-Saharan Africa (351 per 100 000 livebirths, 95% CI 168–732) were similar to those in south Asia (336 per 100 000 livebirths, 247–458), with far greater variability within sites in sub-Saharan Africa. Stillbirth and neonatal mortality rates were approximately two times higher in sites in south Asia than in sub-Saharan Africa (stillbirths: 35·1 per 1000 births, 95% CI 28·5–43·1 vs 17·1 per 1000 births, 12·5–25·8; neonatal mortality: 43·0 per 1000 livebirths, 39·0–47·3 vs 20·1 per 1000 livebirths, 14·6–27·6). 40–45% of pregnancy-related deaths, stillbirths, and neonatal deaths occurred during labour, delivery, and the 24 h postpartum period in both regions. Obstetric haemorrhage, non-obstetric complications, hypertensive disorders of pregnancy, and pregnancy-related infections accounted for more than three-quarters of maternal deaths and stillbirths. The most common causes of neonatal deaths were perinatal asphyxia (40%, 95% CI 39–42, in south Asia; 34%, 32–36, in sub-Saharan Africa) and severe neonatal infections (35%, 34–36, in south Asia; 37%, 34–39 in sub-Saharan Africa), followed by complications of preterm birth (19%, 18–20, in south Asia; 24%, 22–26 in sub-Saharan Africa). Interpretation: These results will contribute to improved global estimates of rates, timing, and causes of maternal and newborn deaths and stillbirths. Our findings imply that programmes in sub-Saharan Africa and south Asia need to further intensify their efforts to reduce mortality rates, which continue to be high. The focus on improving the quality of maternal intrapartum care and immediate newborn care must be further enhanced. Efforts to address perinatal asphyxia and newborn infections, as well as preterm birth, are critical to achieving survival goals in the Sustainable Development Goals era. Funding: Bill & Melinda Gates Foundation
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