Businesses cluster to achieve agglomeration benefits. However, research in developing countries suggests that the economic environment limits small business’ propensity to benefit from agglomerations. The study examines the location, networking patterns, formal structures and owner characteristics of 1256 micro businesses from ten industries and thirteen sample areas in Toluca, Mexico. First, the thesis analyses whether clustering has a positive impact on the success rates of the surveyed enterprises, e.g. higher sales per employee. On an industry scale only Retail benefits from agglomerations economies. However, results of the neighborhood data show that specific areas benefit from urbanization economies. Overall, the study finds that businesses located within agglomerations, have higher levels of formalization, networking and professional training, hence constituting a more sophisticated base for economic development. Conclusions can be drawn for development policies and programs, arguing for a more differentiated approach of small business development depending on business location and cluster characteristics.

GIS has been utilized in cultural resources management for decades, yet its application has been largely isolated to predicting the occurrence of archaeological sites. Federal and State agencies are required to protect archaeological sites that are discovered on their lands, but their resources and personnel are very limited. A new methodology is evaluated that uses modern light detection and ranging (LiDAR) and historic aerial photogrammetry to create digital terrain models (DTMs) capable of identifying sites that are most at risk of damage from changes in terrain. Results revealed that photogrammetric modeling of historic aerial imagery, with limitations, can be a useful decision making tool for cultural resources managers to prioritize conservation and monitoring efforts. An attempt to identify key environmental factors that would be indicative of future topographic changes did not reveal conclusive results. However, the methodology proposed has the potential to add an affordable temporal dimension to future digital terrain modeling and land management. Furthermore, the methods have global applicability because they can be utilized in any region with an arid environment.

Urban areas experience the loss of natural stream channels through conversion to artificial conveyances. This process tends to target headwater and other low order streams. The purpose of this study is to determine the patterns of stream loss in Denton, Texas, and explore the regulatory structure that manages these streams. Historic and current maps and stream data are used to map Denton's streams and categorize them according to their vertical connectivity as: 1) "intact", streams that are open to the atmosphere and connect to groundwater; 2) "concrete", channelized streams open to the atmosphere but cut off from groundwater; and 3) "buried", streams disconnected from the atmosphere and groundwater. A review of federal, state, and local regulatory codes and interviews with local government officials and other stakeholders elucidates stream management in Denton. Results from these analyses reveal high rates of stream loss in the urban center with low rates overall. The federal Clean Water Act and the local Environmentally Sensitive Areas code serve as the primary protective measures for natural streams. These regulations discourage stream impacts through expensive and complex permitting requirements. However the policies allow minor impacts which may cause cumulative effects. This study aims to inform future policy-making decisions …

When an earthquake happens, one of the most important tasks of disaster managers is to conduct damage assessment; this is mostly done from remotely sensed data. This study presents a new method for building detection and damage assessment using high-resolution satellite images and LiDAR data from Port-au-Prince, Haiti. A graph-cut method is used for building detection due to its advantages compared to traditional methods such as the Hough transform. Results of two methods are compared to understand how much our proposed technique is effective. Afterwards, sensitivity analysis is performed to show the effect of image resolution on the efficiency of our method. Results are in four groups. First: based on two criteria for sensitivity analysis, completeness and correctness, the more efficient method is graph-cut, and the final building mask layer is used for damage assessment. Next, building damage assessment is done using change detection technique from two images from period of before and after the earthquake. Third, to integrate LiDAR data and damage assessment, we showed there is a strong relationship between terrain roughness variables that are calculated using digital surface models. Finally, open street map and normalized digital surface model are used to detect possible road blockages. Results of …

Disease prevalence varies with geographic location. This research pursues a medical geographic perspective and examines the spatial variations in disease patterns between Obuasi, a gold mining town and Asankrangwa, a non gold mining town in Ghana, West Africa. Political ecology/economy and the human ecology frameworks are used to explain the prevalence of diseases. Mining alters the environment and allows disease causing pathogens and vectors to survive more freely than in other similar environments. Certain diseases such as upper respiratory tract infections, ear infections, sexually transmitted diseases such as HIV/AIDS and syphilis, certain skin diseases and rheumatism and joint pains may have a higher prevalence in Obuasi when compared to Asankrangwa due to the mining in Obuasi.

Coastal marshes and wetlands are vital natural resources that offer habitats for plants and animals, serve as ecological filtration for soil and water pollutants, and act as protection for coastlines. Fishing, both commercial and sport, has a large economic impact in the study area – the Gulf Coast between Galveston Bay, TX and Oak Grove, LA. The objective of this research was to determine the contribution of Hurricane Ike storm surge sedimentation to long-term marsh aggradation in Texas and Louisiana coastal marshes. The research hypothesized that Hurricane Ike’s storm surge deposit would be equal to decades and possibly even a century’s worth of the average annual non-storm sedimentation. A quantitative field study was performed. The storm surge deposit was examined in a series of 15 transects covering approximately 180 km east of Hurricane Ike’s landfall. Nine of the 15 transects were re-surveyed a year after the initial measurement to assess preservation of the deposit. The results demonstrate that Hurricane Ike contributed between 10 to 135 years’ worth of sediment to coastal marshes along the coasts of Texas and Louisiana, and the sediment deposits have been preserved for over two years.

This paper presents methods and results of county-level population estimation using Landsat Thematic Mapper (TM) images of Denton County and Collin County in Texas. Landsat TM images acquired in March 2000 were classified into residential and non-residential classes using maximum likelihood classification and knowledge-based classification methods. Accuracy assessment results from the classified image produced using knowledge-based classification and traditional supervised classification (maximum likelihood classification) methods suggest that knowledge-based classification is more effective than traditional supervised classification methods. Furthermore, using randomly selected samples of census block groups, ordinary least squares (OLS) and geographically weighted regression (GWR) models were created for total population estimation. The overall accuracy of the models is over 96% at the county level. The results also suggest that underestimation normally occurs in block groups with high population density, whereas overestimation occurs in block groups with low population density.

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.

The Aubrey Clovis site is one of the oldest late-Pleistocene sites in North America, dated to ~11,550 B.P., and contains two camps with a range of lithic debitage, numerous hearths, and excellent faunal preservation. Couched in rules of classification, a series of artifact distributions are analyzed with qualitative and quantitative techniques, including maps produced in a geographic information system (GIS) and tests of artifact associations using correlation statistics. Theoretical and methodological protocols are promoted to improve spatial analysis in archaeology. The results support the short-term occupation interpretation and expose the differential patterning among bone, stone, and raw materials distributions. The spatial structure and diverse content of the site challenge models of Clovis-age people as strictly big game hunters.

Rain gardens are low impact developments designed to mitigate a suite of issues associated with urban stormwater runoff. The site for this study was a Denton City rain garden at the Denton Waste Water Treatment Plant. Nitrogen and phosphorus removal was examined in light of two overflow events comprised of partially treated wastewater from an upslope anaerobic digester pond. Nitrate removal efficiency was examined across differing dry spell intervals of 5, 8, and 12 d, displaying a moderate negative correlation (r2 = 0.59). Continued phosphorus removal capacity was assessed, showing phosphorus removal in cases where P was in excess of 0.8 mg/L, reflecting an equilibrium phosphorus concentration. A high expanded shale component in the soil media (25%) was likely a factor in the continued removal of phosphorus. Overall the rain garden proved to be a large source of nitrate (+425%) and total nitrogen (+61%) by mass. The study showed that while the rain garden intercepted a large volume of partially treated wastewater during the overflow events, preventing it from reaching a nearby creek, the mitigation of an acute event has extended to a chronic one as nitrogen is gradually processed and flushed from the system as nitrate.

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.

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.

Valley development through erosional processes typically tends to create symmetrical valleys. Over time, water cuts through the substrate to create valleys, gorges, and canyons for which the sides are the valley are evenly sloped. However, there are anomalies to this process. Asymmetrical valleys have been well-documented even in areas of uniform substrate or little tectonic uplift. One proposed explanation for the asymmetry of these valleys is differential insolation. This may lead to different microclimates from one slope to another which alter the rate and extent of erosion. Since the differences in received insolation vary with latitude (especially in streams that flow along an east/west axis), it follows that the degree of asymmetry should also vary with latitude if differential insolation is a primary driving factor in the development of these valleys. To evaluate if insolation plays a role in the development of asymmetrical valleys, this study examines variability in asymmetry across 447 valleys in nine study areas located at different latitudes. The degree of asymmetry for each valley was measured by using 30 meter resolution digital elevation models (DEMs) to determine the slope angle of each side of the valley. Asymmetry was measured by computing a ratio of the average …

Urbanization causes various environmental issues including water pollution, air pollution, and solid waste. Urbanization of watersheds has a profound influence on the quality of stormwater runoff. The quality of stormwater runoff is highly associated with land use. This study analyzed the exceedance frequency of stormwater quality in five watersheds of Denton over eleven years and also analyzed the relationship between stormwater quality and land use/cover of each watershed. The results showed that the most of the water quality parameters that were examined in the Lower Pecan watershed exceeded their threshold most frequently. The higher frequency of exceedance in this watershed can be attributed to the wastewater treatment plant and landfill site. Total suspended solids and turbidity were frequently exceeded in Hickory and Clear Creek watersheds. Conductivity was found to have highest percentage of exceedance in Upper Pecan and Cooper watersheds. Thus, rural watersheds were related with higher exceedance of TSS and turbidity whereas urban watersheds were related with higher exceedance of conductivity.

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 …

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.

Terroir combines the physical landscape of the vineyard with the grapevines and the methods and techniques used to produce wine from the grapes. This study used a GIS to identify the characteristics of the physical landscape in Pottawattamie, Mills, Montgomery, Fremont, and Page counties in southwestern Iowa. The components were combined in the GIS using a weighted linear index to identify areas suitable for vineyard development and to identify the general characteristics of the area. Vineyard owners were interviewed to help determine the weighting system to use in the GIS and to determine their perceptions of how the physical landscape impacts their vineyards, as well as to determine what grape varieties they plant in their vineyards and their decisions on making wine from these grapes. This information was collected to identify whether the vineyard owners had developed a sense of place for their vineyards and how this sense might aid them in the development of a terroir for their wines. The resulting perceptions about the individual wineries were then considered in conjunction with the results from the GIS modeling to understand how the physical landscape influences the concepts of sense of place and terroir in southwest Iowa. The physical landscape …

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.

This paper presents an investigation of sedimentary deposition, soil formation, and pedoturbation in the Animas River Valley to determine the provenience of archaeological deposits in an open field at Aztec Ruins National Monument, NM outside of the Greathouse complex. Four stratigraphic pedounits correlated with active fan deposition have been proposed for the lower terrace in the project area with only one of these units retaining strong potential for buried archaeological deposits from the Anasazi late Pueblo II/Pueblo III period. The distal fan on the lower terrace and the Animas River floodplain appear to show poor potential for archaeological deposits either due to shallow sediment overburden with historic disturbance or alluvial activity during or after occupation. Based on these findings, four other zones of similar fan development have been identified throughout the Animas Valley and are recommended for subsurface testing during future cultural resource investigations.

Twenty four percent of all HIV infections in the United States occur among adults aged 50 and older (mature adults), yet little is understood of the dynamics of HIV infection among this group in Texas. Data from 1999 to 2009 examined the relationship between HIV spatial and temporal patterns affecting socio-economic and demographic variables including poverty, gender, race/ethnicity and mode of exposure. Results revealed highest HIV infection rates among White homosexual men, Black males engaged in IV-drug use, Black female heterosexuals and minorities in poverty. Concentrations of HIV infection among mature adults were located primarily in urban centers of Houston and Dallas and indicated increasing HIV infection rates from 1999 to 2009. These results will assist future allocation of resources by zip code in urban areas for this understudied population.

This thesis presents a Web-based geographic information system (GIS) application for campus emergency management that allows users to visualize, integrate, and analyze student population, facilities, and hazard data for efficient emergency management of University of North Texas before, during, and after a terrorism event. End-users can locate and search the source area of an event on a digital map from the ArcIMS-based Website. The website displays corresponding population information and attributes of impacted facilities in real time. School officials and first responders including police, firefighters and medical personnel can promptly plan the appropriate rescue and response procedures according to the displayed results. Finally, the thesis outlines the limitations of Web-based GIS in the arena of campus emergency management.

In this research, hyperspectral and multispectral images were utilized for vegetation studies in the greenbelt corridor near Denton. EO-1 Hyperion was the hyperspectral image and Landsat Thematic Mapper (TM) was the multispectral image used for this research. In the first part of the research, both the images were classified for land cover mapping (after necessary atmospheric correction and geometric registration) using supervised classification method with maximum likelihood algorithm and accuracy of the classification was also assessed for comparison. Hyperspectral image was preprocessed for classification through principal component analysis (PCA), segmented principal component analysis and minimum noise fraction (MNF) transform. Three different images were achieved after these pre-processing of the hyperspectral image. Therefore, a total of four images were classified and assessed the accuracy. In the second part, a more precise and improved land cover study was done on hyperspectral image using linear spectral unmixing method. Finally, several vegetation constituents like chlorophyll a, chlorophyll b, caroteoids were distinguished from the hyperspectral image using feature-oriented principal component analysis (FOPCA) method and which component dominates which type of land cover particularly vegetation were correlated.

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.

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 …