Lindahl Beebe (walliraq0)

With huge natural gas(NG) reserves and current low (1%) share of non-hydro renewables in Sub-Saharan Africa (SSA), can natural gas offer SSA a low-carbon energy transition? Employing data from 1980 to 2017, this paper investigates the impact of NG consumption on SSA's CO2 emissions using data-driven nonparametric additive regression(NPAR) which can reveal both linear and nonlinear effects. Augmenting NPAR with translog production function(TPF) estimates of interfuel substitution elasticities and bias technological progress over sample period(advantage of TPF), we further provide evidence of the indirect effect of NG consumption on SSA's CO2 emissions through mechanism analysis. From the empirical results, the linear effect shows NG positively impact CO2 emissions while the nonlinear effect indicates a downward decreasing trend (meaning expansion in NG consumption will gradually lower CO2 emissions). Nonlinearly, urbanization and energy efficiency also show positive "inverted U-Shaped" and "downward slopping" n.Soil organic carbon (SOC) significantly influences soil fertility, soil water holding capacity, and plant productivity. In this study, we applied two boosted regression tree (BRT) models to map SOC stocks across China in the 1980s and the 2010s. The models incorporated nine environmental variables (climate, topography, and biology) and 8897 (in the 1980s) and 4534 (in the 2010s) topsoil (0-20 cm) samples. During the two study periods, 20% of the soil samples were randomly selected for model testing, and the remaining samples were used as a training set to construct the models. The verification results showed that incorporating climate environment variables significantly improved the model prediction in both study periods. Mean annual temperature, mean annual precipitation, elevation, and the normalized difference vegetation index were the dominant environmental factors affecting the spatial distribution of SOC stocks. The full-variable model predicted similar spatial distributions of SOC stocks for the 1980s and the 2010s. SOC stocks in China showed an increasing trend over the past 30 years, from 3.9 kg m-2 in the 1980s to 4.6 kg m-2 in the 2010s. In both periods, topsoil SOC stocks were mainly stored in agroecosystems, forests, and grasslands in the 1980s, with values of 9.5, 12.0, and 11.4 Pg C, respectively. Our study provides reliable information on Chain's carbon distribution, which can be used by land managers and the national government to formulate relevant land use and carbon sequestration policies.A vertical subsuperficial tidal flow constructed wetland (TFCW) operated under flooded time (FT) variation, was evaluated in the removal of carbonaceous, nitrogenous, and phosphorous matter from urban stream water. The TFCW downflow (117 L) was filled with bricks (44% porosity) and vegetated with Althernanthera philoxeroides (32 plants m-2). The TFCW was operated under different flooded times - Stage A (48 h), B (36 h), C (24 h), and D (12 h), organic loading rates of 19.58-43.83 gCOD m-2 d-1, 3.68-6.94 gTN m-2 d-1 and 0.93-2.00 gTP m-2 d-1 and volumetric load rates of 46.8, 58.5, 78.0 and 11.7 L d-1. No significant differences were observed in the removal efficiencies to Chemical Oxygen Demand (COD 66 to 94%), Total Ammonia Nitrogen (TAN 58 to 87%), and Total Nitrogen (TN 53 to 78%) among the stages, and nitrate concentrations lower than 6 mg L-1 in the effluent. selleck compound High Total Phosphorus removal was obtained in FT of 48 h (TP 79%). Total phosphorus loading rate was a limiting factor in TP removal, which reduced along with the reduction of FT. The nitrifying community was present over time since ammonia-oxidizing bacteria (Nitrosospira) and nitrite-oxidizing bacteria (Nitrobacter and Nitrospira) were identified in operational stages with variation in relative abundance, but TAN removal efficiency did not show significant differences. There was no change in the denitrifying community structure, indic