The ratio of nitrogen (N) to argon (Ar) in landfill gas was compared to the atmospheric gas ratio to quantify the balance between N generating (anaerobic ammonium oxidation, denitrification) and N consuming (nitrogen fixation) processes on three landfills undergoing in-situ stabilization. In the aerated landfills, as much as 22% of the extracted N could be explained by net denitrification, with coexisting aerobic and anaerobic domains fostering nitrification-dependent denitrification. Nitrogen fixation was also occasionally observed.
View Article and Find Full Text PDFUrban development often results in compacted soils, impairing soil structure and reducing the infiltration and retention of stormwater runoff from impervious features. Biochar is a promising organic soil amendment to improve infiltration and retention of stormwater runoff. Soil at the disconnection between impervious and pervious surfaces represents a critical biochar application point for stormwater management from urban impervious features.
View Article and Find Full Text PDFApplication of biochar to landfill cover soils can purportedly improve methane (CH) oxidation rates, but understanding the combined effects of soil texture, compaction, and biochar on the activity and composition of the methanotrophs is limited. The amendment of wood biochar on two differently textured landfill cover soils at three compaction levels of the Proctor density was explored by analyzing changes in soil physical properties relevant to methane oxidation, the effects on CH oxidation rates, and the composition of the methanotrophic community. Loose soils with and without biochar were pre-incubated to equally elevate the CH oxidation rates.
View Article and Find Full Text PDFTransient changes in wettability complicate the prediction of biochar's hydrologic effects. Biochar wetting properties were characterized from poultry litter biochar (PLBC) produced from slow pyrolysis at temperatures between 300 and 600°C with water drop penetration time (persistence of hydrophobicity) and contact angle (CA; severity of hydrophobicity) measurements. Hydrophobicity was associated with semivolatile organic compounds coating PLBC surfaces, which resulted in 24.
View Article and Find Full Text PDFBackground: Pre-implantation genetic diagnosis (PGD) is an assisted reproductive technology procedure which provides parents with the option of conducting genetic analyses to determine if a mutation is present in an embryo. Though studies have discussed perceptions of PGD from a general population, couples or high-risk women, no studies to date have specifically examined PGD usage among men. This study sought to explore perceptions and attitudes towards PGD among males who either carry a BRCA mutation or have a partner or first degree relative with a BRCA mutation.
View Article and Find Full Text PDFBackground: Debate continues between on-pump or off-pump approach for coronary artery bypass grafting (CABG). We used off-pump coronary artery bypass grafting (OPCAB) as a tool within a decision-making algorithm driven by the patient-related factors of coronary anatomy and comorbidity. Our analysis presents this decision algorithm and describes outcomes using this approach.
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