Nuclear wastes from Hanford's processing for separation of plutonium are stored in massive, buried, single‐shell tanks in 18 tank farms. These so‐called tank wastes were initially thermally hot because of radioactive decay, and many exhibited extreme chemical character in terms of pH, salinity, and radionuclide concentration. At present, 67 of the 149 single shell tanks are suspected to have released over 1.9 million L of tank waste to the vadose zone, with most leak events occurring between 1950 and 1975. Boreholes have been placed through the largest vadose zone plumes to define the extent of contaminant migration and to develop conceptual models of processes governing the transformation, retardation, and overall transport of tank waste residuals. Laboratory studies with sediments so collected have shown that ion exchange, precipitation and dissolution, and surface complexation reactions have occurred between the tank wastes and subsurface sediments, moderating their chemical character and retarding the migration of select contaminants. Processes suspected to facilitate the far‐field migration of immobile radionuclides including stable aqueous complex formation and mobile colloids were found to be potentially operative but unlikely to occur in the field, with the exception of cyanide‐facilitated migration of 60Co. Certain fission product oxyanions (Mo, Ru, Se, Tc) and nitrates are the most mobile of tank waste constituents because their adsorption is suppressed by large concentrations of waste anions, the vadose zone clay fraction is negative in surface charge, and, unlike Cr, their reduced forms are unstable in oxidizing environments. Reaction/process‐based transport modeling is beginning to be used for predictions of future contaminant mobility and plume evolution.
Objective To assess sleep practices, and investigate their relationship with maternal and fetal outcomes, among pregnant Ghanaian women. Methods In a cross-sectional study conducted at Korle Bu Teaching Hospital, Accra, Ghana, between June and July 2011, postpartum women were interviewed within 48 hours of delivery about sleep quality and practices during pregnancy. Interviews were coupled with a systematic review of participants’ medical charts for key outcomes including maternal hypertension, pre-eclampsia, premature delivery, low birth weight, and stillbirth. Results Most women reported poor sleep quality during pregnancy. Snoring during pregnancy was independently associated with pre-eclampsia (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.4–8.5; P=0.007). The newborns of women who reported supine sleep during pregnancy were at increased risk of low birth weight (OR, 5.0; 95% CI, 1.2–20.2; P=0.025) and stillbirth (OR, 8.0; 95% CI, 1.5–43.2; P=0.016). Low birth weight was found to mediate the relationship between supine sleep and stillbirth. Conclusion The present findings in an African population demonstrate that maternal sleep, a modifiable risk factor, has a significant role in pre-eclampsia, low birth weight, and subsequently stillbirth.
Partitioning interwell tracer tests (PITT) were used ID determine the spatial distribution and volume of residual trichloroethene (TCE) present in alluvium beneath the Portsmouth Gaseous Diffusion Plain in southern Ohio. Its first use at this site was in support of the design of a surfactant flood to remove the residual DNAPL (dense nonaqueous phase liquids) from the alluvial aquifer. The second application assessed the performance of the surfactant flood. The average DNAPL saturation in the first PITT was 0.1 to 0.2% in a swept pore volume of 4500 gallons (17.000 L). A second PITT was undertaken following the surfactant flood and yielded an average residual saturation of 0.06% in a swept pore volume of 3400 gallons (13.000 L), the reduction in pore volume being due to the confinement of the tracers to the lower sand and gravel unit of the alluvium. The design, operation, and analysis of the two PM Is provided strong evidence of a buried channel that controls the spatial distribution of the residual TCI: DNAPL in the basal sand and gravel aquifer and must be considered in the eventual full remediation of this aquifer.
BackgroundLittle is known about how optimism/pessimism and health-related quality of life compare across cultures.MethodsThree samples of pregnant women in their final trimester were recruited from China, Ghana, and the United States (U.S.). Participants completed a survey that included the Life Orientation Test - Revised (LOT-R, an optimism/pessimism measure), the Short Form 12 (SF-12, a quality of life measure), and questions addressing health and demographic factors. A three-country set was created for analysis by matching women on age, gestational age at enrollment, and number of previous pregnancies. Anovas with post-hoc pairwise comparisons were used to compare results across the cohorts. Multivariate regression analysis was used to create a model to identify those variables most strongly associated with optimism/pessimism.ResultsLOT-R scores varied significantly across cultures in these samples, with Ghanaian pregnant women being the most optimistic and least pessimistic and Chinese pregnant women being the least optimistic overall and the least pessimistic in subscale analysis. Four key variables predicted approximately 20% of the variance in overall optimism scores: country of origin (p = .006), working for money (p = .05); level of education (p = .002), and ever being treated for emotional issues with medication (p < .001). Quality of life scores also varied by country in these samples, with the most pronounced difference occurring in the vitality measure. U.S. pregnant women reported far lower vitality scores than both Chinese and Ghanaian pregnant women in our sample.ConclusionThis research raises important questions regarding what it is about country of origin that so strongly influences optimism/pessimism among pregnant women. Further research is warranted exploring underlying conceptualization of optimism/pessimism and health related quality of life across countries.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.