Search Results

open access

Estimating Buruli Ulcer Prevalence in Southwestern Ghana

Description: Mycobacterium ulcerans is sweeping across sub-Saharan Africa, but little is known about the mode of transmission and its natural reservoirs. Since the only effective treatment is excision of the infection and surrounding tissue, early diagnosis and treatment is the only way to reduce the havoc associated with Buruli ulcer. Using data from a national case search survey conducted in Ghana during 2000 and suspected risk factors this study tests the hypothesized factors and probes the challenges of developing a spatial epidemiological regression model to explain Buruli ulcer prevalence in the southwestern region of Ghana representing 42 districts. Results suggest that prevalence is directly related to the degree of land cover classified as soil, elevation differential, and percent rural population of the area.
Date: August 2007
Creator: Denton, Curtis James
Partner: UNT Libraries
open access

An environmental justice assessment of the light rail expansion in Denton County, Texas.

Description: This study analyzes the proposed passenger rail line expansion along US Interstate Highway 35 in Denton County, Texas. A multi-dimensional approach was used to investigate potential environmental justice (EJ) consequences from the expansion of the transportation corridor. This study used empirical and historical evidence to identify and prioritize sites for potential EJ concerns. Citizen participation in the decision making process was also evaluated. The findings of this research suggest that the southeast Denton community has the highest potential for environmental justice concerns. This study concludes by offering suggestions for an effective public participation process. These include the incorporation of a community's local history into an environmental justice assessment, and tailoring the public planning process to the demographics and culture of the residents.
Date: August 2007
Creator: Moynihan, Colleen T.
Partner: UNT Libraries
open access

Determining the Suitability of Functional Landscapes and Wildlife Corridors Utilizing Conservation GIS Methods in Denton County, Texas.

Description: Denton County's unique cultural and natural landscape has undergone dramatic transformations during the past two centuries due to agricultural, urban and suburban processes which accelerated the loss and removal of native habitat and wildlife. This research sought out to identify the remaining natural areas which retain their natural features and support wildlife. Research methodology included fundamental principles of Conservation Planning, Geographical Information Systems, and Habitat Evaluation Procedures for identifying remnant functional landscapes and wildlife corridors. The final results suggest that Denton County's rural landscape retains the functional properties and elements suitable for habitat conservation and wildlife corridors, while also pointing to the fundamental obstacles to conservation posed by continued growth and private landownership.
Date: August 2007
Creator: Sales, Joshua
Partner: UNT Libraries
open access

Assessment of Sediment Runoff from Natural Gas Well Development Sites.

Description: Storm water sediment runoff from disturbed landscapes has the potential to impair aquatic environments. Small construction sites of 1-5 acres in the United States are currently regulated by the United States Environmental Protection Agency to minimize storm water runoff damages to the environment. Gas well construction sites are similar to other construction sites in how the landscape is altered, but are not similarly regulated. This study identified sediment runoff from gas well development sites by collecting it in traps and weirs, and by measuring sediment debris lobes. Sediment primarily consisted of silt and clay sized particles. Sediments from two gas well sites formed five debris lobes that ranged in size from 325 to 3,290 square feet. Sediment loadings estimated from the debris lobes averaged 57.1 tons per year/acre. Future studies should focus on further quantification of sediment movement off of gas well sites and identify effective erosion control methods.
Date: May 2007
Creator: Havens, David Loran
Partner: UNT Libraries
open access

Measuring the value of transit access for Dallas County: A hedonic approach.

Description: Advocates of urban light rail transit argue that positive developments around station area(s) should offset the costs of implementing a transit system by creating more livable communities and enhance surrounding residential property values. In some cases, decreased urban landscape aesthetics have been reported. The purpose of this study is to contribute to this debate via an analysis of the impact of the Dallas Area Rapid Transit system on residential property values in Dallas County. By examining the impact of distance on property values of two features of the DART system: the transit station and the rail line, and by holding a series of structural variables constant, a net change in value can be calculated using a multi-regression model.
Date: August 2007
Creator: Leonard, Christopher
Partner: UNT Libraries
open access

National Patterns and Community Impacts of Major Domestic U.S. Military Base Closures, 1988-present

Description: This thesis analyses major U.S. military bases closed by the Base Realignment and Closure (BRAC) Commission since 1988. The study focuses on geographic patterns of pre-existing versus BRAC bases, statistical attributes, environmental restoration, and reuse of bases. Comparative case studies supplement the analysis, highlighting rural versus urban location, success versus failure, politics, conflict, and local versus national goals. Thesis findings are that: 92 bases closed versus 97 commonly published; a fairly even national closure pattern occurred, indicating Commission efforts to achieve equity, except for three closure clusters indicating efforts to consolidate functions in some regions and leave others; base reuse, while commonly perceived negatively, has been positive in most cases; the BRAC process is becoming more efficient, such that allowed years between BRAC closure decisions and base closures should be reduced from six to three years to benefit both communities and the Defense Department.
Date: August 2004
Creator: Webster, Sean T.
Partner: UNT Libraries
open access

Interpreting Prehistoric Patterns: Site Catchment Analysis in the Upper Trinity River Basin of North Central Texas

Description: Archaeologically site catchment analysis produces valuable information regarding prehistoric subsistence strategies and social organization. Incorporating archaeological data into catchment analyses is an effective strategy to develop regional models of prehistoric site selection and settlement patterns. Digital access to data permits the incorporation of multiple layers of information into the process of synthesizing regional archaeology and interpreting corresponding spatial patterning. GIS software provides a means to integrate digital environmental and archaeological data into an effective tool. Resultant environmental archaeology maps facilitate interpretive analysis. To fulfill the objectives of this thesis, GIS software is employed to construct site catchment areas for archaeological sites and to implement multivariate statistical analyses of physical and biological attributes of catchments in correlation with assemblage data from sites. Guided by ecological, anthropological and geographical theories hypotheses testing evaluates patterns of prehistoric socio-economic behavior. Analytical results are summarized in a model of prehistoric settlement patterns in North Central Texas.
Date: December 2004
Creator: Williams, Marikka Lin
Partner: UNT Libraries
open access

Integrating GIS with Benthic Metrics: Calibrating a Biotic Index to Effectively Discriminate Stream Impacts in Urban Areas of the Blackland Prairie Eco-Region

Description: Rapid Bioassessment Protocols integrate a suite of community, population, and functional metrics, determined from the collection of benthic macroinvertebrates or fish, into a single assessment. This study was conducted in Dallas County Texas, an area located in the blackland prairie eco-region that is semi-arid and densely populated. The objectives of this research were to identify reference streams and propose a set of metrics that are best able to discriminate between differences in community structure due to natural variability from those caused by changes in water quality due to watershed impacts. Using geographic information systems, a total of nine watersheds, each representing a different mix of land uses, were chosen for evaluation. A total of 30 metrics commonly used in RBP protocols were calculated. Efficacy of these metrics to distinguish change was determined using several statistical techniques. Ten metrics were used to classify study area watersheds according to stream quality. Many trends, such as taxa presence along habitat quality gradients, were observed. These gradients coincided with expected responses of stream communities to landscape and habitat variables.
Date: December 2003
Creator: Earnest, Steven F. P.
Partner: UNT Libraries
open access

GIS Modeling of Wetlands Elevation Change in Response to Projected Sea Level Rise, Trinity Bay, Texas

Description: This study is a test of a methodology to predict changes in elevation and shoreline position of coastal wetlands in Trinity Bay, Texas, in response to projected sea level rise. The study combines numerical modeling and a geographic information system. A smoothing technique is used on a United States Geographical Survey (USGS) digital elevation model to obtain elevation profiles that more accurately represent the gently sloping wetlands surface. The numerical model estimates the expected elevation change by raster cell based on input parameters of predicted sea level rise, mineral and organic sedimentation rates, and sediment autocompaction rates. A GIS is used to display predicted elevation changes and changes in shoreline position as a result of four projected sea level rise scenarios over the next 100 years. Results demonstrate that this numerical model and methodology are promising as a technique of modeling predicted elevation change and shoreline migration in wetlands. The approach has potential utility in coastal management applications.
Date: December 2005
Creator: Lee, Erica Anne
Partner: UNT Libraries

Water systems, water policy, and Karst terrain: An analysis of the complex relationships between geology, economy, public perceptions, and policy in southern Trelawny, Jamaica.

Description: Jamaica has an abundance of freshwater resources, however, a lack of infrastructure makes treated, piped water inaccessible in many areas. Through literature reviews and site visits, this thesis is an analysis of how the people and land, and money and policy, interact with one another in relation to Jamaica's freshwater resources and water infrastructure. Special attention is given to the island's type-example Cockpit karst geology; tourism, mining, and farming's relation to this karst; types of water delivery systems in rural southern Trelawny's Cockpit Country; southern Trelawny residents' perceptions of the water situation; and policy and development goals in the context of Jamaica and southern Trelawny. I hope to bring attention to the unique social, geologic, and developmental context of water in Jamaica, and more specifically to garner attention for major water infrastructure improvements in south Trelawny. A number of recommendations for improvements with policy and infrastructure are made.
Access: Restricted to the UNT Community Members at a UNT Libraries Location.
Date: December 2005
Creator: McCall, Sarah
Partner: UNT Libraries
open access

Hydrological Impacts of Urbanization: White Rock Creek, Dallas Texas

Description: This research project concerns changes in hydrology resulting from urbanization of the upper sub-basin of the White Rock Creek Watershed in Collin and Dallas Counties, Texas. The objectives of this study are: to calculate the percent watershed urbanized for the period of 1961 through 1968 and the period of 2000 through 2005; to derive a 1960s average unit hydrograph and a 2000s average unit hydrograph; and, to use the two averaged hydrographs to develop a range of hypothetical storm scenarios to evaluate how the storm response of the watershed has changed between these two periods. Results of this study show that stormflow occurs under lower intensity precipitation in the post-urbanized period and that stormflow peaks and volumes are substantially larger compared to the pre-urbanized period. It is concluded that changes in watershed surface conditions resulting from urbanization have lowered the precipitation-intensity threshold that must be surpassed before storm run-off is generated.
Date: December 2005
Creator: Vicars, Julie Anne Groening
Partner: UNT Libraries
open access

Identifying Cultural and Non-cultural Factors Affecting Litter Patterns in Hickory Creek, Texas

Description: Plastic deposition in hydrological systems is a pervasive problem at all geographic scales from loci of pollution to global ocean circulation. Much attention has been devoted to plastic deposition in marine contexts, but little is known about inputs of plastics into local hydrological systems, such as streams. Any attempt to prevent plastic litter must confront people’s behaviors, so archaeological concepts are used to distinguish between various cultural inputs (e.g., littering) and non-cultural forces (e.g., stream transport) that affect litter patterns on the landscape. Litter surveys along Hickory Creek in Denton, TX, are used to assess these factors.
Date: August 2014
Creator: Carpenter, Evan S.
Partner: UNT Libraries
open access

Effects of Non-homogeneous Population Distribution on Smoothed Maps Produced Using Kernel Density Estimation Methods

Description: Understanding spatial perspectives on the spread and incidence of a disease is invaluable for public health planning and intervention. Choropleth maps are commonly used to provide an abstraction of disease risk across geographic space. These maps are derived from aggregated population counts that are known to be affected by the small numbers problem. Kernel density estimation methods account for this problem by producing risk estimates that are based on aggregations of approximately equal population sizes. However, the process of aggregation often combines data from areas with non-uniform spatial and population characteristics. This thesis presents a new method to aggregate space in ways that are sensitive to their underlying risk factors. Such maps will enable better public health practice and intervention by enhancing our ability to understand the spatial processes that result in disparate health outcomes.
Date: December 2014
Creator: Jones, Jesse Jack
Partner: UNT Libraries
open access

Spatial Patterns in Development Regulation: Tree Preservation Ordinances of the DFW Metropolitan Area

Description: Land use regulations are typically established as a response to development activity. For effective growth management and habitat preservation, the opposite should occur. This study considers tree preservation ordinances of the Dallas-Fort Worth metropolitan area as a means of evaluating development regulation in a metropolitan context. It documents the impact urban cores have on regulations and policies throughout their region, demonstrating that the same urban-rural gradient used to describe physical components of our metropolitan areas also holds true in terms of policy formation. Although sophistication of land use regulation generally dissipates as one moves away from an urban core, native habitat is more pristine at the outer edges. To more effectively protect native habitat, regional preservation measures are recommended.
Date: August 2011
Creator: Cox, Carissa
Partner: UNT Libraries
open access

Gentrification in Oklahoma City: Examining Urban Revitalization in Middle America

Description: Gentrification applies not only to the largest and oldest cities; it is a multi-scalar phenomenon playing out in smaller and less prominent settings as well. This study examines temporal changes in property values, demographic characteristics, and types of businesses in the central Oklahoma City area. A major urban revitalization project which began in 1993 created strong gentrification characteristics near the renewal's epicenter, the Bricktown entertainment district. Data suggest that several specific neighborhoods in the surrounding area exhibited rising property values, improving educational attainment rates, decreasing household sizes, and a shift toward cosmopolitan retail activity. While it is evident that Bricktown has been transformed, the socio-economic traits of surrounding neighborhoods have been altered by the ripple effects of urban renewal.
Date: August 2011
Creator: Petty, Clint C.
Partner: UNT Libraries
open access

An Investigation of the Relationship between HIV and Prison Facilities in Texas: The Geographic Variation and Vulnerable Neighborhood Characteristics

Description: Previous research suggests that prisons may be fueling the spread of HIV infection in the general population. In 2005, the HIV rate was more than 2.5 times higher in US prison populations. Environmental factors in prisons such as illicit drug use and unprotected sexual activities can be conducive for HIV transmission. Because the vast majority of prison inmates are incarcerated for less than three years, transmission of HIV between prison inmates and members of the general population may occur at a high rate. The environment in which an individual lives and the entities that comprise it affect the health of that person. Thus the location of prisons within communities, as well as socio-demographic characteristics may influence the geography of HIV infection. HIV surveillance data, obtained from the Texas Department of State Health Services, were used to investigate the relationship between the location of prison units in Texas and HIV infection rates in the surrounding zip codes. The results suggest that HIV prevalence rates are higher among geographic areas in close proximity to a prison unit. With continued behavioral risks and low treatment adherence rates among individuals infected with HIV, there is a possibility of increased HIV prevalence. Vulnerable places, locations with higher HIV prevalence, should be targeted for resource allocation and HIV prevention and care service. This study illustrates the importance of spatial analysis of places vulnerable to increased HIV prevalence in creating more effective public health prevention strategies and interventions.
Date: August 2011
Creator: Kutch, Libbey
Partner: UNT Libraries
open access

The Landscape Legacies of Gas Drilling in North Texas

Description: In North Texas, the Barnett Shale underlies large areas of the Dallas-Fort Worth Metroplex (DFW), which magnifies debates about the externalities of shale gas development (SGD). Continued demand for natural gas and expansive urbanization in DFW will cause more people to come in contact with drilling rigs, gas transport, and other urban shale gas landscapes. Thousands of gas wells within the DFW region occupy a large, yet scattered land surface area. DFW city planners, elected officials, and other stakeholders must deal with current and future urban growth and the surface impacts that are associated with gas development. This research examines how shale gas landscapes affect urban land uses, landscapes, and patterns of development in DFW. The study focuses on multiple fast growing DFW municipalities that also have high numbers of gas well pad sites. This study asks what are the spatial characteristics of gas well production sites in DFW and how do these sites vary across the region; how do gas well production sites affect urban growth and development; and how are city governments and surface developers responding to gas well production sites, and what are the dominant themes of contestation arising around gas well production sites and suburban growth?
Date: May 2016
Creator: Sakinejad, Michael Cyrus
Partner: UNT Libraries
open access

The Study of Temporal and Spatial Variability of Degree Day Factor of Snowmelt in Colorado

Description: Snowmelt is one of the major sources of surface water supply and ground-water recharge in high elevation areas and can also cause flooding in snow dominated watersheds. Direct estimation of daily snowmelt requires daily snow water equivalent (SWE) measurements that are not always available, especially in places without monitoring stations. There are two alternative approaches to modeling snowmelt without using direct measurements of SWE, temperature-based and energy-based models. Due to its simplicity, computational efficiency, and less input data requirement, the temperature-based method is commonly used than the energy-based method. In the temperature-index approach snowmelt is estimated as a linear function of average air temperature, and the slope of the linear function is called the degree-day factor (DDF). Hence, the DDF is an essential parameter for utilizing the temperature-based method to estimate snowmelt. Thereby, to analyze the spatial properties of DDF, 10 years DDF from the entire state of Colorado was calculated for this research. Likewise, to study the temporal properties, DDFs for 27 years from the White Yampa water basin and the Colorado Headwaters water basin were calculated. As a part of the spatial analysis, the calculated DDFs were correlated with spatial variables (slope, aspect, latitude and elevation) and a spatial correlation graph was created to observe the possibility of predicting DDF. Also a multivariate regression model was prepared using these spatial variables to predict the DDF using spatial variables. Further, the DDFs calculated from Colorado headwaters and the White Yampa water basins were correlated for annual temporal variation, daily variation, variation with peak snow water equivalent and variation with important temporal cycles like accumulation period and melting period of snowmelt. The result obtained from this study showed that the variability of DDF is more dependent upon temporal factors compared to the spatial factors. Also, the results showed that predicting …
Date: May 2016
Creator: Pokhrel, Pranav
Partner: UNT Libraries
open access

An Exploration of the Ground Water Quality of the Trinity Aquifer Using Multivariate Statistical Techniques

Description: The ground water quality of the Trinity Aquifer for wells sampled between 2000 and 2009 was examined using multivariate and spatial statistical techniques. A Kruskal-Wallis test revealed that all of the water quality parameters with the exception of nitrate vary with land use. A Spearman’s rho analysis illustrates that every water quality parameter with the exception of silica correlated with well depth. Factor analysis identified four factors contributable to hydrochemical processes, electrical conductivity, alkalinity, and the dissolution of parent rock material into the ground water. The cluster analysis generated seven clusters. A chi-squared analysis shows that Clusters 1, 2, 5, and 6 are reflective of the distribution of the entire dataset when looking specifically at land use categories. The nearest neighbor analysis revealed clustered, dispersed, and random patterns depending upon the entity being examined. The spatial autocorrelation technique used on the water quality parameters for the entire dataset identified that all of the parameters are random with the exception of pH which was found to be spatially clustered. The combination of the multivariate and spatial techniques together identified influences on the Trinity Aquifer including hydrochemical processes, agricultural activities, recharge, and land use. In addition, the techniques aided in identifying areas warranting future monitoring which are located in the western and southwestern parts of the aquifer.
Date: August 2011
Creator: Holland, Jennifer M.
Partner: UNT Libraries
open access

Faunal Exploitation during the Depopulation of the Mesa Verde Region (A. D. 1300): A Case Study of Goodman Point Pueblo (5MT604)

Description: This analysis of faunal remains from Goodman Point Pueblo (5MT604), a large village occupied just before the ancestral Puebloans permanently left southwestern Colorado at the end of the thirteenth century, explores the effect of dietary stress during abandonment in the Four Corners region. As archaeologists, we interpret what these former cultures were like and what resources they used through what they left behind. By specifically looking at faunal remains, or remains from food resources, environmental change and dietary stress can be assessed. Identifications of taxa identified at Goodman Point are made explicit via a systematic paleontology. This is followed by site-level taxonomic abundances and spatial analysis. Then, effects of technological innovations, environmental change, and sample quality are examined as alternate explanations of shifts in foraging efficiency, particularly related to animal hunting. Analyzing why and if the availability of faunal resources changes over time helps to clarify why the ancestral Puebloans left southwestern Colorado.
Date: August 2011
Creator: Hoffman, Amy Susan
Partner: UNT Libraries
open access

Hurricane Storm Surge Sedimentation on the McFaddin National Wildlife Refuge, Texas: Implications for Coastal Marsh Aggradation

Description: This study uses the storm surge sediment beds deposited by Hurricanes Audrey (1957), Carla (1961), Rita (2005) and Ike (2008) to investigate spatial and temporal changes in sedimentation rates on the McFaddin National Wildlife Refuge in Southeast Texas. Fourteen sediment cores were collected along a transect extending from 90 to 1230 meters inland from the Gulf Coast. Storm-surge-deposited sediment beds were identified by texture, organic content, carbonate content, the presence of marine microfossils, and Cesium-137 dating. The hurricane-derived sediment beds are marker horizons that facilitate assessment of marsh sedimentation rates from nearshore to inland locations as well as over decadal to annual timescales. Near the shore, on a Hurricane Ike washover fan, where hurricane-derived sedimentation has increased elevation by up to 0.68 m since 2005, there was no measurable marsh sedimentation in the period 2008-2014. Farther inland, at lower elevations, sedimentation for the period 2008-2014 averaged 0.36 cm per year. The reduction in sedimentation in the period 2008-2014 on the nearshore part of the marsh is likely due to reduced flooding in response to increased elevation from hurricane storm surge sediment deposition. These results provide valuable knowledge about the sedimentary response of coastal marshes subject to storm surge deposition and useful guidance to public policy aimed at combating the effects of sea level rise on coastal marshes along the Gulf of Mexico.
Date: May 2016
Creator: Hodge, Joshua B.
Partner: UNT Libraries
open access

Looking Outward from the Village: The Contingencies of Soil Moisture on the Prehistoric Farmed Landscape near Goodman Point Pueblo

Description: Ancestral Pueblo communities of the central Mesa Verde region (CMVR) became increasingly reliant on agriculture for their subsistence needs during Basketmaker III (BMIII) through Terminal Pueblo III (TPIII) (AD 600–1300) periods. Researchers have been studying the Ancestral Pueblo people for over a century using a variety of methods to understand the relationships between climate, agriculture, population, and settlement patterns. While these methods and research have produced a well-developed cultural history of the region, studies at a smaller scale are still needed to understand the changes in farming behavior and the distribution of individual sites across the CMVR. Soil moisture is the limiting factor for crop growth in the semi-arid region of the Goodman Watershed in the CMVR. Thus, I constructed the soil moisture proxy model (SMPM) that is on a local scale and focuses on variables relevant to soil moisture – soil particle-size, soil depth, slope, and aspect. From the SMPM output, the areas of very high soil moisture are assumed to represent desirable farmland locations. I describe the relationship between very high soil moisture and site locations, then I infer the relevance of that relationship to settlement patterns and how those patterns changed over time (BMIII – TPIII). The results of the model and its application help to clarify how Ancestral Pueblo people changed as local farming communities. The results of this study indicates that farmers shifted away from use of preferred farmland during Terminal Pueblo III, which may have been caused by other cultural factors. The general outcome of this thesis is an improved understanding of human-environmental relationships on the local landscape in the CMVR.
Date: August 2016
Creator: Brown, Andrew D
Partner: UNT Libraries
open access

The Impact of Chinese Privet (Ligustrum Sinense) on the Survival and Re-Establishment of Native Plants at the Dallas Floodway Extension

Description: Invasive woody shrubs are a problem when they displace native species and threaten habitats, especially those that harbor rare or endangered species. They not only compete with native plants, but also alter habitat and food that many organisms depend upon. Invasive plants undergo a release from their specialist predators in the nonnative range, providing them advantages over native species. Because modes and pathways of how invasive species spread are not fully understood, predicting spread and implementing restoration ecological controls remain inexact. Due to the lack of comparative studies on woody shrubs, especially invasive privets, we understand very little about conditions affecting their invasiveness. A study was conducted near Dallas, Texas to determine if privet has allelopathic properties that influences growth of native plants. Soil nutrients and other analyses were made and compared between field plots supporting privet, plots in which privet has been removed, and plots where privet has not been observed. In some field plots, natives were planted under the three previously mentioned conditions, and their survival and condition were monitored to evaluate effects of privet on their establishment and growth. It was found that Chinese privet did hinder seed germination in red mulberry, soapberry and beautyberry and root formation in beautyberry cuttings. The soil in the sites were found to be normal for bottomland forests that endured two flooding events within one year.
Date: August 2016
Creator: Barnett, Jennifer M
Partner: UNT Libraries
Back to Top of Screen