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UNT Scholarly Works
Using GIS technology to identify areas of tuberculosis transmission and incidence
Date: October 13, 2004
Creator: Moonan, Patrick K.; Bayona, Manuel; Quitugua, Teresa N.; Oppong, Joseph R.; Dunbar, Denise; Jost, Kenneth C. et al
Description: This article discusses using GIS technology to identify areas of tuberculosis transmission and incidence. Background: Currently in the U.S. it is recommended that tuberculosis screening and treatment programs be targeted at high-risk populations. While a strategy of targeted testing and treatment of persons most likely to develop tuberculosis is attractive, it is uncertain how best to accomplish this goal. In this study the authors seek to identify geographical areas where on-going tuberculosis transmission is occurring by linking Geographic Information Systems (GIS) technology with molecular surveillance. Methods: This cross-sectional analysis was performed on data collected on persons newly diagnosed with culture positive tuberculosis at the Tarrant County Health Department (TCHD) between January 1, 1993 and December 31, 2000. Clinical isolates were molecularly characterized using IS6 110-based RFLP analysis and spoligotyping methods to identify patients infected with the same strain. Residential addresses at the time of diagnosis of tuberculosis were geocoded and mapped according to strain characterization. Generalized estimating equations (GEE) analysis models were used to identify risk factors involved in clustering. Results: Evaluation of the spatial distribution of cases within zip-code boundaries identified distinct areas of geographical distribution of same strain disease. The authors identified these geographical areas as having increased ...
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc122162/
Spatial Distribution of Solutes in Aquifer Outcrop Zones along the Brazos River, East-Central Texas
Date: 2011
Creator: Hudak, Paul F.
Description: This articles discusses the spatial distribution of solutes in Aquifer outcrop zones along the Brazos River in east-central, Texas. Concentrations of several solutes - nitrate, arsenic, sulfate, boron, chloride, and bromide - along with total dissolved solids (TDS) in ten counties bordering the Brazos River in east-central, Texas were compiled, mapped, and analyzed relative to regional land use and geology. Agriculture and oil/gas production are major activities and potential sources of groundwater contamination in the study area. Data were compiled from 104 water wells with a median depth of 446 ft (136 m) in the outcrop zones of six sedimentary aquifers: Carizzo-Wilcox, Queen City, Sparta, Yegua-Jackson, Gulf Coast, and Brazos Alluvium. Only two observations surpassed the 44.3 mg/L drinking water standard for nitrate, and four observations exceeded the 10 ug/L standard for arsenic. The median chloride concentration was 53 mg/L; however, the maximum level was almost three times the secondary drinking water standard of 250 mg/L. Chloride, bromide, sulfate, and boron concentrations resembled TDS patterns, with numerous samples exceeding secondary TDS drinking water standards in the Yegua-Jackson Aquifer. Most chloride/bromide ratios were between 100 and 300. Overall, results of this study suggest that natural processes exert a primary control on ...
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc152433/
Nitrate and Chloride Concentrations in Groundwater beneath a Portion ofn the Trinity Group Outcrop Zone, Texas
Date: 2012
Creator: Hudak, Paul F.
Description: This article discusses nitrate and chloride concentrations in groundwater beneath a portion of the Trinity Group outcrop zone in Texas. Using a geographic information system and statistics, the author evaluated spatial distributions of nitrate and chloride concentrations in groundwater in an area of north-central Texas with agricultural activity, in addition to oil and natural gas exploration and production. Data were compiled from 40 water wells sampled in 2007. Nitrate concentrations in three wells exceeded the maximum contaminant level (44 mg/L) for drinking water. The highest nitrate concentration was 149 mg/L, and concentrations were generally higher in shallower wells. Chloride concentrations exceeded the 250 mg/L secondary drinking water standard in two wells, with no significant association between chloride concentration and well depth. Results of this study suggest localized human impacts, especially for nitrate, and identify areas warranting future monitoring.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc152435/
Nitrate, Arsenic and Selenium Concentrations in The Pecos Valley Aquifer, West Texas, USA
Date: 2010
Creator: Hudak, Paul F.
Description: This article discusses nitrate, arsenic, and selenium concentrations in the Pecos Valley Aquifer in west Texas. Nitrate, arsenic, and selenium concentrations in the Pecos Valley Aquifer of west Texas compiled, mapped, and analyzed in the context of local geology and land use. Alluvial deposits of sand, silt, clay, and gravel compose the unconfined aquifer. Ranching and farming are predominant land uses in the rural study area. Data were tabulated from 79 water wells with a median depth of 75 m and mapped with a geographic information system (GIS). The wells were sampled between the years 2003 and 2008. Total dissolved solids (TDS) concentrations in the aquifer were very high, with a median value of 2,687 mg/L. Approximately 18% of observations exceeded the 44.27 mg/L drinking water standard for nitrate, whereas 6% exceeded the 10 μg/L standard for selenium. There was a statistically significant, direct correlation between arsenic and selenium, as well as between nitrate and selenium concentrations. Moreover, arsenic and selenium concentrations were significantly higher in shallower wells. Probable sources of groundwater contamination in the study area include natural (geological) sources and agricultural activity.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc152432/
Potential Hazards of Wind Energy For Rare, Tereatened, and Endangered Birds and Batsin Texas
Date: 2011
Creator: Graham, T.L. & Hudak, Paul F.
Description: This article discusses the potential hazards of wind energy for rare, tereatened, and endangered birds and Batsin, Texas. The purpose of this study was to estimate relative potential hazard index (PHI) for 31 bird and ten bat species based upon the percentage of known or observed species range area (by county) within each wind speed classification. Results demonstrate considerable range in relative hazard, with the lesser prairie chicken and ferruginous hawk among the most potentially impacted birds; and the pale Townsend's bat, western small-footed bat, and big free-tailed bat among the most potentially impacted bats. While additional data are necessary to establish actual impacts of wind developments, relative potential hazard indices may help prioritize future studies.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc152434/
Evaluation Of WEPP For Runoff And Sediment Yield Prediction On Natural Gas Well Sites
Date: 2008
Creator: Wachal, David J.; Harmel, R. Daren; Banks, Kenneth E. & Hudak, Paul F.
Description: This article discusses the evaluation of WEPP for runoff and sediment yield prediction on natural gas well sites. Abstract: Natural gas exploration and production requires land-disturbing construction activities that have the potential to accelerate soil loss due to land cover modifications, increased slopes, and flow concentration. In the U.S., nearly 30,000 new gas wells are drilled each year. Erosion modeling has been successfully used for decades to predict soil loss and conservation effects on agricultural fields, rangelands, and forests, although much less research has been conducted on the application of erosion models for disturbed construction site conditions. The objective of this research was to evaluate Water Erosion Prediction Project (WEPP) runoff and sediment yield predictions relative to measured data from two natural gas well sites (referred to as GW1 and GW2) in north central Texas. Model parameters were adjusted from WEPP default parameters based on available literature and model observations. A low effective hydraulic conductivity value (0.75 mm h⁻¹) resulted in successful runoff predictions. Agreement between predicted and measured sediment yields was accomplished by increasing rill and interrill erodibility values and decreasing critical shear stress values from default values. WEPP performance was evaluated with the Nash-Sutcliffe efficiency (NSE), root mean ...
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc155619/
Geographic Distribution of HIV/AIDS in Texas
Date: December 1, 2011
Creator: Oppong, Joseph R.
Description: This presentation is part of the faculty lecture series UNT Speaks Out on HIV/AIDS. This presentation discusses the geographic distribution of HIV/AIDS in Texas and the associated factors.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc71783/