Fecal Coliform Transport through Intact Soil Blocks Amended with Poultry Manure

Poultry production in Kentucky increased almost 200% between 1991 and 1995. Their waste is typically land applied, and fecal pathogen runoff and infiltration may cause nonpoint source groundwater pollution. We looked at the preferential flow of fecal coliforms through undisturbed soil blocks since fecal bacteria typically infiltrate the soil profile to contaminate groundwater. Poultry manure was uniformly distributed on top of sod-covered or tilled (upper 12.5 cm) soil blocks and the blocks were irrigated. Drainage was collected in 100 uniformly spaced cells beneath each block and analyzed for fecal coliform content and drainage volume. The spatial distribution of drainage and fecal coliforms through the soil blocks was not uniform. Fecal coliforms appeared where most drainage flowed. Drainage water from each soil block consistently exceeded 200 000 fecal coliforms per 100 mL and was as great as 30 million fecal coliforms per 100 mL of leachate collected. Fecal coliforms leached as a pulse, but the breakthrough of fecal coliforms through tilled blocks was delayed with respect to the breakthrough of fecal coliforms through sod-covered blocks. Rainfall on a well-structured soil will cause the preferential movement of fecal bacteria, even with unsaturated flow conditions, and could contribute to fecal coliform concentrations in shallow groundwater that exceed standards for domestic discharge and primary contact water in Kentucky (200 fecal coliforms/100 mL)

Tillage Slows Fecal Bacteria Infiltration through Soil

Bacterial pathogens can degrade ground water quality by infiltrating and eroding from land treated with poultry wastes. The potential for ground water contamination (as well as associated health risks and cost of water treatment) greatly depends on the depth of soil to the water table or bedrock and soil structure. Pathogens must move through the soil profile to contaminate ground water (although sinkholes can provide a direct channel from the soil surface to the water table in karst areas). Deep soils have less potential for contamination than shallow soils. Structureless soils retain fecal bacteria better than well structured soils. Research at UK indicates that surface-applied fecal bacteria, and other contaminants, travel rapidly toward ground water through soil pores in well structured, intact soil. Tillage disrupts pores and channels in the tilled layer, and increases water and bacteria contact with soil. To improve our understanding of bacterial movement, and of the potential for ground water contamination, we decided to examine whether tillage affected fecal coliform transport through intact soil amended with poultry wastes. We used poultry wastes because their disposal is an increasingly important waste management issue in western Kentucky

Fecal Coliform Transport through Intact Soil Blocks Amended with Poultry Manure

Poultry production in Kentucky increased almost 200% between 1991 and 1995. Their waste is typically land applied, and fecal pathogen runoff and infiltration may cause nonpoint source groundwater pollution. We looked at the preferential flow of fecal coliforms through undisturbed soil blocks since fecal bacteria typically infiltrate the soil profile to contaminate groundwater. Poultry manure was uniformly distributed on top of sod-covered or tilled (upper 12.5 cm) soil blocks and the blocks were irrigated. Drainage was collected in 100 uniformly spaced cells beneath each block and analyzed for fecal coliform content and drainage volume. The spatial distribution of drainage and fecal coliforms through the soil blocks was not uniform. Fecal coliforms appeared where most drainage flowed. Drainage water from each soil block consistently exceeded 200 000 fecal coliforms per 100 mL and was as great as 30 million fecal coliforms per 100 mL of leachate collected. Fecal coliforms leached as a pulse, but the breakthrough of fecal coliforms through tilled blocks was delayed with respect to the breakthrough of fecal coliforms through sod-covered blocks. Rainfall on a well-structured soil will cause the preferential movement of fecal bacteria, even with unsaturated flow conditions, and could contribute to fecal coliform concentrations in shallow groundwater that exceed standards for domestic discharge and primary contact water in Kentucky (200 fecal coliforms/100 mL)

Politicians’ perspectives on voice and accountability: evidence from a survey of South African local councillors

A growing body of research exists on democratic accountability. Much of this research focuses on citizen strategies for expressing their views, and on efforts to hold politicians and government service providers accountable. Despite this research, we in fact know little about how politicians in young democracies view these aspects of democratic governance. Given that accountability can be understood as a feedback ‘loop’ between citizens and elected representatives, it is necessary to gain a better understanding of the norms and values of politicians themselves, the pressures they face and the ways that they communicate with their constituents. This paper details findings from an original survey of approximately 1,000 South African councillors in 2016 and 2017 to explore what representation and accountability looks like from their perspective. How do they understand the various links in the accountability chain, including citizen input and deliberation, norms of good government and pressures from political parties, friends and family? The quality of democratic accountability, and the success of interventions to improve citizen representation, may depend on the norms and beliefs held by elected representatives. Findings state that even in a political context defined by strong parties, the descriptive representation of South African politicians has important substantive implications. Individual-level characteristics such as the race, gender, wealth and age of councillors meaningfully predict attitudes and perceptions on a range of important questions about voice and accountability.DFIDUSAIDSidaOmidyar Networ

An improved criterion for new particle formation in diverse atmospheric environments

A dimensionless theory for new particle formation (NPF) was developed, using an aerosol population balance model incorporating recent developments in nucleation rates and measured particle growth rates. Based on this theoretical analysis, it was shown that a dimensionless parameter <i>L</i><sub>Γ</sub>, characterizing the ratio of the particle scavenging loss rate to the particle growth rate, exclusively determined whether or not NPF would occur on a particular day. This parameter determines the probability that a nucleated particle will grow to a detectable size before being lost by coagulation with the pre-existing aerosol. Cluster-cluster coagulation was shown to contribute negligibly to this survival probability under conditions pertinent to the atmosphere. Data acquired during intensive measurement campaigns in Tecamac (MILAGRO), Atlanta (ANARChE), Boulder, and Hyytiälä (QUEST II, QUEST IV, and EUCAARI) were used to test the validity of <i>L</i><sub>Γ</sub> as an NPF criterion. Measurements included aerosol size distributions down to 3 nm and gas-phase sulfuric acid concentrations. The model was applied to seventy-seven NPF events and nineteen non-events (characterized by growth of pre-existing aerosol without NPF) measured in diverse environments with broad ranges in sulfuric acid concentrations, ultrafine number concentrations, aerosol surface areas, and particle growth rates (nearly two orders of magnitude). Across this diverse data set, a nominal value of <i>L</i><sub>Γ</sub>=0.7 was found to determine the boundary for the occurrence of NPF, with NPF occurring when <i>L</i><sub>Γ</sub><0.7 and being suppressed when <i>L</i><sub>Γ</sub>>0.7. Moreover, nearly 45% of measured <i>L</i><sub>Γ</sub> values associated with NPF fell in the relatively narrow range of 0.1<<i>L</i><sub>Γ</sub><0.3

Random walk on disordered networks

Random walks are studied on disordered cellular networks in 2-and 3-dimensional spaces with arbitrary curvature. The coefficients of the evolution equation are calculated in term of the structural properties of the cellular system. The effects of disorder and space-curvature on the diffusion phenomena are investigated. In disordered systems the mean square displacement displays an enhancement at short time and a lowering at long ones, with respect to the ordered case. The asymptotic expression for the diffusion equation on hyperbolic cellular systems relates random walk on curved lattices to hyperbolic Brownian motion.Comment: 10 Pages, 3 Postscript figure

The O I] 1641A line as a probe of symbiotic star winds

The neutral oxygen resonance 1302A line can, if the optical depth is sufficiently high, de-excite by an intercombination transition at 1641A to a metastable state. This has been noted in a number of previous studies but never systematically investigated as a diagnostic of the neutral red giant wind in symbiotic stars and symbiotic-like recurrent novae. We used archival $IUE$ high resolution, and GHRS and STIS medium and high resolution, spectra to study a sample of symbiotic stars. The integrated fluxes were measured, where possible, for the O I 1302A and O I] 1641A lines. The intercombination 1641A line is detected in a substantial number of symbiotic stars with optical depths that give column densities comparable with direct eclipse measures (EG And) and the evolution of the recurrent nova RS Oph 1985 in outburst. In four systems (EG And, Z And, V1016 Cyg, and RR Tel), we find that the O I] variations are strongly correlated with the optical light curve and outburst activity. This transition can also be important for the study of a wide variety of sources in which an ionization-bounded H II region is imbedded in an extensive neutral medium, including active galactic nuclei, and not only for evaluations of extinction.Comment: accepted for publication in Astronomy and Astrophysics (2010 Feb. 23), in press, NASA-GSFC-Code 66