Search Results

Analyzing Tuberculosis Vulnerability and Variables in Tarrant County
Over 9 million new cases of tuberculosis (TB) were reported worldwide in 2013. While the TB rate is much lower in the US, its uneven distribution and associated explanatory variables require interrogation in order to determine effective strategies for intervention and control. However, paucity of case data at fine geographic scales precludes such research. This research, using zip code level data from 837 confirmed TB cases in Tarrant County obtained from Texas Department of State Health Services, explores and attempts to explain the spatial patterns of TB and related risk markers within a framework of place vulnerability. Readily available census data is then used to characterize the spatial variations in TB risk. The resulting model will enable estimations of the geographic differences in TB case variables using this readily available census data instead of time-consuming and expensive individual data collection.
Assessing Rainfall Interception by Urban Tree Canopies in Denton, Texas
Rainfall interception is one mechanism by which tree canopies can reduce surface runoff in urban areas. The objectives of this research were to: 1) quantify rainfall interception by urban tree canopies, and 2) determine the influence of vegetation and microenvironmental factors on rainfall interception rates. In the city of Denton, Texas, 30 mature post oak (Quercus stellata) and blackjack oak (Quercus marilandica) trees were selected for study. Trees were assigned to one of three categories: clusters of trees on greenspace (CG), isolated trees on greenspace (IG), and isolated trees surrounded by pavement (IP). Throughfall (the volume of water that travels through the canopy and reaches the soil surface) collectors were placed beneath these trees and rainfall collectors were placed in nearby open areas. Throughfall and rainfall were collected daily from 19 March to 4 July. Interception was calculated as the difference between throughfall and gross rainfall. Over the study period, there were 27 days with measurable rainfall; daily rainfall ranged from 1-51 mm. Over the sampling period, rainfall interception for individual trees ranged from -10% to 49%, indicating high spatial variability in interception. Percent interception was highest for the CG treatment (22.7 ± 3.8 SE), intermediate for IG (27.4 ± 2.3 SE), and lowest for IP (9.1 ± 4.9 SE). Factors like wind exposure, wind-driven rain and overall tree health may help explain this variability. This research will contribute to our knowledge of hydrological fluxes in urban areas and the role of urban green infrastructure in stormwater runoff mitigation.
An Assessment of Riparian Buffer Effectiveness in the Upper Hickory Creek Watershed: A GIS Approach Using the Riparian Buffer Delineation Equation (RBDE) and the Buffer Improvement Potential Percentage (BP)
As population increases and urbanization occurs, watershed management will be critical in the protection of water resources in North Central Texas. By 2040, Denton County will nearly double its 2010 population. The Upper Hickory Creek Watershed lies west of Denton and empties into Lake Lewisville. Lake Lewisville provides drinking water for Denton, Dallas, and other neighboring cities. Mitigation of non-point source pollutants as a result of urban and agricultural practices is essential to protecting Lake Lewisville water resources. A common best management practice used to mitigate pollutants is the protection of riparian ecotones that occupy river corridors; however, recent agricultural and urban practices are diminishing these ecosystems and their services. In this paper, the riparian buffer delineation equation (RBDE) is used to assess the current state of Upper Hickory Creek Watershed to aid in the monitoring of the riparian buffers along stream corridors. While the RBDE was used as pre-assessment tool for the riparian buffer effectiveness in the watershed, a new form of the equation was used to evaluate riparian buffer improvement potential (BP) in conjunction with Denton County parcel data to provide insights into buffer effectiveness and identify areas for improvement on a landowner scale.
Automated Tree Crown Discrimination Using Three-Dimensional Shape Signatures Derived from LiDAR Point Clouds
Discrimination of different tree crowns based on their 3D shapes is essential for a wide range of forestry applications, and, due to its complexity, is a significant challenge. This study presents a modified 3D shape descriptor for the perception of different tree crown shapes in discrete-return LiDAR point clouds. The proposed methodology comprises of five main components, including definition of a local coordinate system, learning salient points, generation of simulated LiDAR point clouds with geometrical shapes, shape signature generation (from simulated LiDAR points as reference shape signature and actual LiDAR point clouds as evaluated shape signature), and finally, similarity assessment of shape signatures in order to extract the shape of a real tree. The first component represents a proposed strategy to define a local coordinate system relating to each tree to normalize 3D point clouds. In the second component, a learning approach is used to categorize all 3D point clouds into two ranks to identify interesting or salient points on each tree. The third component discusses generation of simulated LiDAR point clouds for two geometrical shapes, including a hemisphere and a half-ellipsoid. Then, the operator extracts 3D LiDAR point clouds of actual trees, either deciduous or evergreen. In the fourth component, a longitude-latitude transformation is applied to simulated and actual LiDAR point clouds to generate 3D shape signatures of tree crowns. A critical step is transformation of LiDAR points from their exact positions to their longitude and latitude positions using the longitude-latitude transformation, which is different from the geographic longitude and latitude coordinates, and labeled by their pre-assigned ranks. Then, natural neighbor interpolation converts the point maps to raster datasets. The generated shape signatures from simulated and actual LiDAR points are called reference and evaluated shape signatures, respectively. Lastly, the fifth component determines the similarity between evaluated and reference shape …
Developing a Soil Moisture-Based Irrigation Scheduling Tool (SMIST) Using Web-GIS Technology
Software as a service (SaaS) is a primary working pattern and a significant application model for next generation Internet application. Web GIS services are the new generation of the Software as a service that can provide the hosted spatial data and GIS functionalities to the practical customized applications. This study focused on developing a webGIS based application, Soil Moisture-Based Irrigation Scheduling Tool (SMIST), for predicting soil moisture in the next seven days using the soil moisture diagnostic equation (SMDE) and the upcoming seven precipitation forecasts made by the National Weather Service (NWS), and ultimately producing an accurate irrigation schedule based on the predicted soil moisture. The SMIST is expected to be capable of improving the irrigation efficiency to protect groundwater resources in the Texas High Plains and reducing the cost of energy for pumping groundwater for irrigation, as an essential public concern in this area. The SMIST comprised an integration of web-based programs, a Hydrometeorological model, GIS, and geodatabase. It integrates two main web systems, the soil moisture estimating web application for irrigation scheduling based on the soil moisture diagnostic equation (SMDE), and an agricultural field delineation webGIS application to prepare input data and the model parameters. The SMIST takes advantage of the latest historical and forecasted precipitation data to predict soil moisture in the user-specified agricultural field(s). In this regard, the next seven days soil moisture versus the soil moisture threshold for normal growth would be presented in the result page of the SMIST to help users to adjust irrigation rate and sequence.
The Geography of Partial-Market Exits: Applying Geospatial and Econometric Methods to Analyze 2017 Department Store Closures in the United States
Many factors have prompted the adoption of partial-market exit strategies in retail as a means of reducing cost and minimizing risk. These mass closures have become more frequent in recent years. Marketers and economists have offered explanations for these closures linked to the rise of e-commerce, the real estate cycle and general changes in consumer taste. The research here marks an attempt to apply geospatial and econometric methods to better understand what factors explain the spatial variation of these closures across the United States. Specifically, the analysis examines the store networks of Sears, J.C. Penney and Macy's- large, established department stores that, collectively, announced over 100 closures at the beginning of 2017. By treating each store as a unit of observation, and a closure as a limited dependent variable, this analysis will attempt to quantify the relationship between place-specific factors and retail closures using Probit modeling. This application of modeling marks a deviation from traditional analyses in retail geography which, up until the early 2000s, have focused almost entirely on store development and growth. The results reveal patterns of spatial clustering of closures in and around the Rust Belt and demonstrate the strong negative effect of competitive agglomeration on the probability of closure.
The Geography of Retail Clinics Post Implementation of the Affordable Care Act
Retail clinics are walk-in clinics designed for convenience and for servicing minor health issues and certain acute conditions. The model began as a way of bringing both convenience and care to areas that have lower levels of access to primary care resources. With the implementation of Affordable Care Act (ACA) in March 2010, populations that were previously uninsured were now required to have access to some level of health insurance. These populations presented a potential new market for retail clinics. This research shows that post implementation of the ACA, retail clinics tend to locate in areas with higher incomes and, generally, greater access to primary care.
Green Entrepreneurialism and the Making of the Trinity River Corridor: The Intersection of Nature and Capital in Dallas, Texas
Since the adoption of neoliberalism, many cities have taken to integrating nature with capital accumulation to create a sense of place. This has been closely tied to urban greening, or green "revitalization." As part of curating this desired character, city governments are working to roll out plans to restore and renew neighborhoods using their natural landscapes through methods such as reforestation, the creation of parks, and commercial development. These cities, deemed Entrepreneurial cities, are increasingly incorporating natural or green spaces into their development of character as part of their branding schemes. This research focuses on the role of nature as the site of economic development and community revitalization within Dallas, Texas. This research examines how the City of Dallas uses nature to attract capital, and how the narratives of development relate to residents' visions for development in the historically neglected Joppa neighborhood in the Trinity River Corridor. Development near Joppa could be an example of how the natural landscape is being used to not only attract developers but also to bring a different ‘class' of resident into the area. By exploring this intersection of nature and capital in Dallas, we can better understand the nuanced ways through which the neoliberalization of nature can lead to deeper social and economic disparities.
Improvement of the Soil Moisture Diagnostic Equation for Estimating Root-Zone Soil Moisture
Soil moisture information can be used accurately in determining the timing and amount of irrigation applied to plants. Pan and Pan et al. proposed a robust and simple daily diagnostic equation for estimating daily soil moisture. The diagnostic equation evaluates the relationship between the soil moisture loss function and the summation weighted average of precipitation. The loss function uses the sinusoidal wave function which employs day of the year (DOY) to evaluate the seasonal variation in soil moisture loss for a given year. This was incorporated into the daily diagnostic equation to estimate the daily soil moisture for a location. Solar radiation is an energy source that drives the energy and water exchanges between vegetation and the atmosphere (i.e., evapotranspiration), and thus impacts the soil moisture dry-down. In this paper, two parameters (the actual solar radiation and the clear sky solar radiation) are introduced into loss function coefficient to improve the estimation of soil moisture. After the Introduction of the solar radiation data into soil moisture loss function, a slight improvement was observed in the estimated daily soil moisture. Pan observed that generally the correlation coefficient between the estimated and the observed soil moisture is above 0.75 and the root mean square error is below 5.0 (%v/v). The introduction solar radiation data (i.e. clear sky solar radiation and actual solar) improve the correlation coefficient average for all the sites evaluated by 0.03 when the root mean square error is generally below 4.5(%v/v) for the entire root zone.
Lithic Production at the Mesilla Phase Placitas Arroyo Site Complex Doña Ana County, New Mexico
This study of lithic analysis shifts attention from typological studies to explicitly behavioral analyses, complimenting studies of both intrasite and intersite patterns of variability and change. Analysis of several assemblages from the Placitas Arroyo site complex reveals changing patterns of raw material procurement and selection, core reduction strategies, as well as tool production and discard. The most striking result thus far is the quite uniform emphasis on flake production from well-prepared cores, and the near absence of manufacture or maintenance of bifacial tools, especially projectile points. Associated with common ground stone artifacts, the flaked stone materials may well represent intensive food processing. Regardless, the technological patterns being revealed by this approach illustrate a productive new means to gain insights into changing behaviors in the Jornada Mogollon cultural tradition.
Location Analysis of Lifestyle Centers: Uncovering Patterns and Potential Driving Factors behind Site Selection
The shopping center has held an important place in the American economy for decades. However, the concept has seen multiple revolution in terms of format. The most recent shopping center concept to gain rapid popularity is the lifestyle center – an outdoor shopping mall made to resemble a pleasant main street setting, with a tenant mix emphasizing dining and entertainment. In other words, the lifestyle center concept is geared toward selling consumers things to do, versus things to buy. This thesis studies the geography of lifestyle centers in the United States in both the large-scale and small-scale view. Results show that lifestyle centers are concentrated into larger urban areas, often with a population of over 1 million. An analysis of spatial agglomeration revealed that lifestyle centers are often several miles away from the nearest traditional mall, indicating that developers do not feel the need to build near established shopping districts where traditional malls lie. Finally, results concerning trade area characteristics show the characteristics of consumers in areas where lifestyle centers have been built. Findings in this study indicate that developers are utilizing a unique approach when selecting sites for lifestyle centers compared to traditional indoor malls.
Memory and Continuity Amidst Irreversible Decline in the Texas Big Empty
This thesis interrogates sense of place and place attachment in the Big Empty on the north central Texas plains. The region stretches from the Red River on the north to the Colorado River basin on the south and from the Cross Timbers on the east to the Caprock escarpment on the west. Since 1930, the Big Empty has seen sustained and severe population decline such that some counties there now register less than a quarter the population they did at their peaks during the interwar years. Through in-depth field interviews, I examine sense of place and place attachment amidst apparently irreversible decline. I also describe conditions of postindustrial rurality arising from rolling reconfigurations of economic and social relations, particularly changes in scale in farming and the diminished centrality of productivist agriculture in local economies and culture, and how these conditions become legible through the study of place.
Photoinduced Toxicity in Early Lifestage Fiddler Crab (Uca longisignalis) Following Exposure to Deepwater Horizon Spill Oil
The 2010 Deepwater Horizon (DWH) oil spill resulted in a large release of polycyclic aromatic hydrocarbons (PAH) into the Gulf of Mexico. PAH can interact with ultraviolet radiation (UV) resulting in increased toxicity, particularly to early lifestage organisms. The goal of this research was to determine the sensitivity of fiddler crab larvae (Uca longisignalis) to photo-induced toxicity following exposure to Deepwater Horizon spill oil in support of the DWH Natural Resource Damage Assessment. Five replicate dishes each containing 20 larvae, were exposed to one of three UV treatments (10%, 50%, and 100% ambient natural sunlight) and one of five dilutions of water accommodated fractions of two naturally weathered source oils. A dose dependent effect of PAH and UV on larval mortality was observed. Mortality was markedly higher in PAH treatments that included co-exposure to more intense UV light. PAH treatments under low intensity sunlight had relatively high survival. These data demonstrate the importance of considering combined effects of non-chemical (i.e. UV exposure) and chemical stressors and the potential for photo-induced effects after exposure to PAH following the Deepwater Horizon spill.
Public Market Trade Areas: Local Goods, Farmers, and Community in the U.S. Southwest Region, 1996-2016
The number of public markets in the United States increased from more than 300 in the 1970s to more than 8,600 by 2016. This increase in markets is related to changes in food production, localism and the local food systems movement, socioeconomic changes, cultural changes, and perceptions of embeddedness. Research on the underlying conditions for the success of public markets is scant in the United States, and especially in the USDA Southwest Region. This study provides analysis of public market locations as compared with non-market locations by drive-time trade areas during a 20-year period, 1996 and 2016, to gain further insights into factors leading to their success. The results from logit regression analyses and simulations of socioeconomic, college-town status, and climate-grid classifications find an increased likelihood of public markets with population, education, college town status, and some climate-grid locations. Median income, surprisingly, has an inverse relationship with public market success. Qualitative data and a literature review point to three types of embeddedness that motivate customers to attend public markets. This study concludes that "local nontradable consumer goods" tied to place are offered at these "nontradable consumption amenities." These amenities are "third places" that promote social interaction and become important places of community, farmer support, and commerce across the Southwest Region.
Reconstructing Identity with Urban Community Agriculture: How Refugees Confront Displacement, Food Insecurity, and Othering through Community Farming
Ethnic and religious conflict, and the deepening of capitalism have led to global diaspora at unprecedented levels. The United Nations High Commissioner for Refugees reported that as of 2015, 1 in every 122 persons worldwide were either a refugee, internally displaced, or seeking asylum. The U.S. currently admits the largest number of refugees worldwide. However, policies fail to reflect the multitude of elements that constitute successful resettlement. Moreover, many refugees come from farming backgrounds and are forced to migrate to a landless urban environment, where their skill sets may not be utilized and farm land is not available. I argue that existing resettlement processes are embedded in logics and practices that alienate humans from nature and from each other through competition, isolation, and placeless environments. Through an exploration in concepts of urban agriculture, place-making, identity, and otherness, and illuminating the experiences of resettled refugees involved in a community gardening project in Fort Worth, Texas, show how the urban refugee garden provides the individual a space to narrate an identity, and to resist industrial agriculture and labor outside their industry. Exploring best practices in resettlement should be a priority to governments, politicians, and communities involved in the process and highlight the reasons to advocate these types of resettlement alternatives.
Redesigning Police Beat Zone Placement to Improve 911 Response Time: A Data Driven Approach
Research suggests that using data driven solutions in policing strategies improves the quality of service provided by the police department. Unfortunately, many police departments, including the Denton Police Department, do not use their spatial data to inform beat zone placement. Analysis of the current beat zone configuration found that there are disparities in the workload, as measured by number of calls for service, between beat zones. Further, there was also a statistically significant difference between the median response times across all the five beat zones in Denton. This means that the median response time varies depending on where the call for service originates. Using readily available data, these police departments can apply methods such as UPAS to improve the quality of service provided by the department. UPAS is a deterministic algorithm that produces a given number of contiguous spatial partitions of approximately equal population size; in this case, calls for service are substituted for population. Although this algorithm was originally developed to create solutions for bio-terrorism response planning, it has been applied to the problem of creating beat zones of roughly equal workload in this research. I have shown that this algorithm results in a beat zone configuration that significantly reduces the difference in workload between the busiest and least busy beat zone (~94% reduction). Assuming an equal distribution of resources across beat zones, having approximately similar workloads should lead to fewer disparities in quality of service.
Retail District Evolution: An Exploration of Retail Structure and Diversity, a Case Study in Denton, Texas
It is well established that national retail chains impact small, single location retail businesses in terms of revenue generation, retail structure, retail type diversity, and location. This study examines the retail structure and diversity of five retail districts in the City of Denton, Texas. The analysis focuses on one central business district (CBD), one traditional retail strip center (University Drive, also known as US HWY 380), one special retail district (Fry Street District), one traditional enclosed shopping mall and associated development (Golden Triangle Mall), and one power retail center (Denton Crossing). The empirical foundation for the investigation is a historical business database covering years 1997 to 2010, obtained from Info Group's Reference USA. This Reference USA database includes location, industry, and status (single versus chain location) information for each business. Retail diversity and evenness were measured for each of the five retail districts using the Simpson's Diversity Index and the Simpsons Measure of Evenness, leading to specification of the differences that exist in retail structure and diversity among the districts. Golden Triangle Mall and Denton Crossing were primarily chain location in composition while Fry Street District, the CBD, and University Drive were primarily single location in composition. Across all years, the single versus chain status of the local business communities did not substantially change within any of the districts. The Fry Street District exhibited the most change in diversity as well as the lowest overall diversity among the retail districts, followed by University Drive and Golden Triangle Mall. The CBD did not experience any major change in retail type diversity. However, all retail districts experienced major changes in retail evenness. Overall for the city, single location retail businesses accounted for the majority of all the retail businesses, however, chain locations employed more people. In total, these findings indicate that the …
Seeds of Disempowerment: Bt cotton and Accumulation by Dispossession in the States of Maharashtra, Telangana, and Andhra Pradesh in India
In 1991, India adopted neoliberalism, a system of political economic practices that promotes private property and free trade, as its political and economic system to promote development in their country. India's neoliberal reform has created issues surrounding human development, resource accumulation, and power struggles. Eleven years later, in 2002, Bt cotton was introduced to the Indian agricultural sector. This research examines how the genetically modified organism Bt cotton is being used to commodify nature in the context of agriculture under neoliberalism. The research focuses on the dispossession of the rural farmers through the commodification of agriculture using Bt cotton. Dispossession of the rural farmers happen through the implications that arise from the commodification of nature. Through Marxist theory of primitive accumulation, this research analyzes accumulation by dispossession and how it neglects the working class and its struggle in rural India. Through this examination, the research will argue alternatives to the dispossession of the working class and the commodification of nature through Bt cotton. Dispossession, in this research, is examined both through working class, but also through the dispossession of biodiversity. Through the loss of biodiversity, the rural farmers are becoming dispossessed from a more sustainable environment. Along with these goals, the research will also incorporate themes of food security through changing landscape of agriculture due to the incorporation of Bt cotton. This research argues the contradictions that are presented through the commodification of agriculture under neoliberalism and provide a contribution to social justice literature, and our understanding of the relationship between technology and the commodification of nature.
Social Vulnerability and Bio-Emergency Planning: Identifying and Locating At-Risk Individuals
In 2006, the United States Congress passed the Pandemic All-Hazards Preparedness Act (PAHPA) which mandated that all emergency preparedness planning shall address at-risk populations. Further, in 2013, the reauthorization of this act, known as PAHPRA, defined at-risk individuals as "children, older adults, pregnant women, and individuals who may need additional response assistance." This vague definition leaves emergency managers, planners, and public health officials with the difficult task of understanding what it means to be at-risk. Further, once identified, the geographic location of at-risk individuals must be obtained. This research first uses the concept of social vulnerability to enhance the understanding of what it means to be "at-risk." Then, by comparing two data disaggregation techniques, areal weighted interpolation and dasymetric mapping, I demonstrate how error of estimation is affected by different scenarios of population distribution and service area overlap. The results extend an existing framework of vulnerability by stratifying factors into quantifiable and subjective types. Also, dasymetric mapping was shown to be a superior technique of data disaggregation compared to areal weighted interpolation. However, the difference in error estimates is low, 5 percent or less in 72 percent of the test cases. Only through local collaboration with community entities can emergency planners access the appropriate data to both: 1) understand the nature of at-risk individuals in their service areas and 2) spatially target resources needed to ensure all individuals are planned for in case of a bio-emergency.
Urban Trees as Sinks for Soot: Deposition of Atmospheric Elemental Carbon to Oak Canopies and Litterfall Flux to Soil
Elemental carbon (EC), a product of incomplete combustion of fossil fuels and biomass, contributes to climate warming and poor air quality. In urban areas, diesel fuel trucks are the main source of EC emissions from mobile sources. After emission, EC is deposited to receptor surfaces via two main pathways: precipitation (wet deposition) and directly as particles (dry deposition). Urban trees may play an important role in removing EC from the atmosphere by intercepting and delivering it directly to the soil. The goal of this research was to quantify the magnitude of EC retention in leaf waxes (in-wax EC) and EC fluxes to the soil via leaf litterfall in the City of Denton, Texas. Denton is a rapidly growing urban location in the Dallas-Fort Worth metropolitan area. A foliar extraction technique was used to determine EC retention in leaf waxes. Foliar samples were collected monthly, from April through July, from pairs of Quercus stellata (post oak, n=10) and Quercus virginiana (live oak, n = 10) trees. Samples were rinsed with water and chloroform in a two-step process to determine EC retained in leaf waxes. A Sunset OC/EC aerosol analyzer was utilized to analyze the EC content of extracts filtered onto quartz-fiber filters. From April through July, leaf litter was collected bi-weekly under 35 trees (20 post oak, 15 live oak), and oven dried to determine dry weight. EC retained by tree canopies was estimated by multiplying in-wax EC by canopy leaf area index, while EC flux to soil was estimated by multiplying in-wax EC by leaf litterfall mass. This study shows that through retention of EC in leaf waxes, urban tree canopies represent important short-term sinks for soot in urban areas.
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