Characterization of pathogen transport in overland flow

Overland transport kinetics of pathogens are controlled, in large part, by soil and vegetation. With an increasing number of concentrated animal operations, there is becoming a greater need to dispose of a vast amount of manure in a single, localized area. Animal manure contains a substantial amount of microbial pathogens, including Cryptosporidium parvum and rotavirus that may pose a threat of potential contamination of water resources. This study examines the kinetics of C. parvum and rotavirus in overland transport, with an overall objective of optimizing the design of best management practices, especially vegetative filter strips. Three soil types are tested (Catlin silt-loam, Alvin fine sandy-loam, Darwin silty-clay), spanning the entire spectrum of typical Illinois soils, in terms of soil texture. A 20-minute rainfall event is produced using a small-scale (1.07 m x 0.66 m) laboratory rainfall simulator over a soil box measuring 0.67 m x 0.33 m. Each soil type is tested for pathogen transport kinetics with bare and vegetated surface conditions. Surface runoff, soil cores, and near-surface runoff are each analyzed for infective C. parvum oocysts and infective rotavirus particles using cell-culture infectivity assays. Results show that vegetation reduces the recovery of infective oocysts in surface runoff by an average of 62% and rotavirus particles by an average of 73%, in addition to delaying the time to the peak recovery. Recovery of infective rotavirus particles from surface runoff of bare Alvin (high sand content) soil is seven times higher than that of infective oocysts. Recovery from surface runoff of bare Darwin (high clay content) soil is nearly one and a half times more for C. parvum than for rotavirus, with the recovery of C. parvum oocysts approaching 40%. Recovery from the soil cores was slightly higher for C. parvum (0.06%) than for rotavirus (0.05%) in the case of the bare Alvin soil, but was slightly higher for rotavirus (0.92%) than C. parvum (0.19%) for the bare Darwin soil condition

Household malaria knowledge and its association with bednet ownership in settings without large–scale distribution programs: Evidence from rural Madagascar

Background: Insecticide–treated bednets are effective at preventing malaria. This study focuses on household–level factors that are associated with bednet ownership in a rural area of Madagascar which had not been a recipient of large–scale ITN distribution. Methods: Data were gathered on individual and household characteristics, malaria knowledge, household assets and bednet ownership. Principal components analysis was used to construct both a wealth index based on household assets and a malaria knowledge index based on responses to questions about malaria. Bivariate and multivariate regressions were used to determine predictors of household bednet ownership and malaria knowledge. Results: Forty–seven of 560 households (8.4%) owned a bednet. In multivariate analysis, higher level of malaria knowledge among household members was the only variable significantly associated with bednet ownership (odds ratio 3.72, P < 0.001). Among respondents, predictors of higher malaria knowledge included higher education levels, female sex and reporting fever as the most frequent or dangerous illness in the community. Household wealth was not a significant predictor of bednet ownership or respondent malaria knowledge. Conclusion: In this setting of limited supply of affordable bednets, malaria knowledge was associated with an increased probability of household bednet ownership. Further studies should determine how such malaria knowledge evolves and if malaria–specific education programs could help overcome the barriers to bednet ownership among at–risk households living outside the reach of large–scale bednet distribution programs

Current Performance Characteristics of NASA Langley Research Center's Cockpit Motion Base and Standardized Test Procedure for Future Performance Characterization

This report documents the updated performance characteristics of NASA Langley Research Center's (LaRC) Cockpit Motion Base (CMB) after recent revisions that were made to its inner-loop, feedback control law. The modifications to the control law will be briefly described. The performance of the CMF will be presented. A short graphical comparison to the previous control law can be found in the appendix of this report. The revised controller will be shown to yield reduced parasitic accelerations with respect to the previous controller. Metrics based on the AGARD Advisory Report No. 144 are used to assess the overall system performance due to its recent control algorithm modification. This report also documents the standardized simulator test procedure which can be used in the future to evaluate potential updates to the control law

Current Performance Characteristics of NASA Langley Research Center's Cockpit Motion Base and Standardized Test Procedure for Future Performance Characterization

This report documents the updated performance characteristics of NASA Langley Research Center's (LaRC) Cockpit Motion Base (CMB) after recent revisions that were made to its inner-loop, feedback control law. The modifications to the control law will be briefly described. The performance of the Cockpit Motion Facility (CMF) will be presented. A short graphical comparison to the previous control law can be found in the appendix of this report. The revised controller will be shown to yield reduced parasitic accelerations with respect to the previous controller. Metrics based on the AGARD Advisory Report No. 144 are used to assess the overall system performance due to its recent control algorithm modification. This report also documents the standardized simulator test procedure which can be used in the future to evaluate potential updates to the control law

Progress in noncommutative function theory

In this expository paper we describe the study of certain non-self-adjoint operator algebras, the Hardy algebras, and their representation theory. We view these algebras as algebras of (operator valued) functions on their spaces of representations. We will show that these spaces of representations can be parameterized as unit balls of certain $W^{*}$-correspondences and the functions can be viewed as Schur class operator functions on these balls. We will provide evidence to show that the elements in these (non commutative) Hardy algebras behave very much like bounded analytic functions and the study of these algebras should be viewed as noncommutative function theory