Spatial Analysis of North Central Texas Traffic Fatalities 2001-2006
Date: December 2010
Creator: Rafferty, Paula S.
Description: A traditional two dimensional (planar) statistical analysis was used to identify the clustering types of North Central Texas traffic fatalities occurring in 2001-2006. Over 3,700 crash locations clustered in ways that were unlike other researched regions. A two dimensional (x and y coordinates) space was manipulated to mimic a one dimensional network to identify the tightest clustering of fatalities in the nearly 400,000 crashes reported from state agencies from 2003-2006. The roadway design was found to significantly affect crash location. A one dimensional (linear) network analysis was then used to measure the statistically significant clustering of flow variables of after dark crashes and daylight crashes. Flow variables were determined to significantly affect crash location after dark. The linear and planar results were compared and the one dimensional, linear analysis was found to be more accurate because it did not over detect the clustering of events on a network.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc33195/
Spatial Analysis of Teen Births in North Central Texas
Date: December 2001
Creator: Donkor, Faustina Fosua
Description: The United States has the highest teen birth rate among western industrialized countries and the highest levels of pregnancy among adolescents (Alan Guttmacher Institute, 1994). While the rate of teen births is high throughout the country, considerable variations exist between and within regions. Texas is one of the 5 leading states with the highest teen birth rates to mothers less than 18 years of age. This research provides a detailed analysis of births to mothers aged between 10 and 19 years in North Central Texas counties. Due to the modifiable area unit problem and to provide a finer geographical scale of analysis, teen births in Dallas County zip codes were examined as a special case study. Statistical and Geographic Information System (GIS) analysis reveal that race/ethnicity, education and income are significant factors in teen births in the region. Single parent households and receipt of public assistance were not statistically significant. Suggestions for reducing vulnerability to teen births are presented.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc3056/
Spatial and Temporal Influences of Water Quality on Zooplankton in Lake Texoma
Date: May 2000
Creator: Franks, Jessica L.
Description: Seventy-one aquatic species including the copepodids and nauplii were identified from Lake Texoma from August 1996 to September 1997. Zooplankton community structure, abundance and spatial and temporal distributions were compared among five lake zones delineated a priori based on chloride concentration. The zones, in order of decreasing chloride concentration, are the Red River zone (RRZ), Red river Transition zone (RRTZ), Main Lake zone (MLZ), Washita River Transition zone (WRTZ) and Washita River zone (WRZ). Bray Curtis Similarity Index showed community structure was most similar in the two Red River arm zones, the two Washita River arm zones and the MLZ. Zooplankton abundance was greatest in the Red River arm (312 org/L), intermediate in the Washita River arm (217 org/L) and least in the Main Lake body (103 org/L). A significant increase in the abundance of a deformed rotifer, Keratella cochlearis, was observed mainly in the Red River arm during a second study from March 1999 to June 1999. Seasonal dynamics, rather than spatial dynamics, were more important in structuring the zooplankton community, especially in the two river arms. Spatial variance was solely attributed to station and zone effects independent of time for a few crustacean species and many of the ...
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc2532/
Spatial and temporal patterns exhibited by select physicochemical and biological water quality parameters in Lake Texoma, Oklahoma and Texas.
Date: August 2004
Creator: Clyde, Gerard A.
Description: From August 1996 through September 1997 eleven fixed stations were sampled monthly in January, March , April , July, August, September, and November and fortnightly in May and June for the purposes of establishing baseline conditions present in Lake Texoma as related to U.S. Army Corps of Engineers chloride control activities in the upper Wichita River, Texas. Five reservoir zones were identified a priori using historical chloride concentration data and include the Red River Zone (RRZ), Red River Transition Zone (RRTZ), Main Lake Body (MLB), Washita River Transition Zone (WRTZ), and Washita River Zone (WRZ) in order of decreasing chloride concentration. The existence of the WRTZ is not supported here, however the Big Mineral Arm in the RRTZ was observed to be highly independent of the mixing patterns observed in the RRTZ and was treated post priori separately from the RRTZ. Spatial and temporal comparisons between reservoir zones were performed on seventeen (17) physicochemical parameters from each of the eleven sampling stations and phytoplankton count data from one sampling station within each reservoir zone and physicochemical parameters were observed to exhibit a fixed spatial gradient. Strong density gradients throughout the reservoir were observed to occur in conjunction with vertical stratification ...
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc4628/
Spatial and Temporal Patterns of Areal and Volumetric Phytoplankton Productivity of Lake Texoma
Date: August 2001
Creator: Baugher, Tessy
Description: Phytoplankton productivity of Lake Texoma was measured for one year from August 1999 to August 2000 for four stations, using the oxygen change method and laboratory incubation. Mean values of the photosynthetic parameters, PBmax and alphaB ranged from 4.86 to 46.39 mg O2.mg Chl-1.hr-1 for PBmax and 20.06 to 98.96 mg O2.mg Chl-1.E-1.m2 for alphaB. These values were in the range to be expected for a highly turbid, temperate reservoir. Estimated gross annual areal productivity ranged from 594 g C.m2.yr-1 (P.Q. = 1.2), at a station in the Washita River Zone to 753 g C.m2.yr-1 at a station in the Red River Zone, of the reservoir. Gross annual areal productivity at Station 17, in the Main Lake Zone, was 708 g C.m2.yr-1. Gross areal and volumetric productivity showed distinct seasonal variation with Photosynthetically Available Radiation (PAR) and temperature. Trophic status estimated on a station-by-station basis, using net productivity values derived from gross productivity and respiration estimates, was mesotrophic for all the stations, though one station approached eutrophy. Net productivity values ranged from 0.74 to 0.91 g C. m-2.d-1. An algal bioassay conducted at two stations in August 2000, revealed that phosphorus was most likely the nutrient limiting photosynthesis at both ...
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc2915/
Spatial Patterns in Development Regulation: Tree Preservation Ordinances of the DFW Metropolitan Area
Date: August 2011
Creator: Cox, Carissa
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.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc84194/
A Spatial-Temporal Analysis of Retail Location and Clustering: A Case Study of Port Huron, MI
Date: December 2007
Creator: Dickinson, Amie M.
Description: Retail geography is a field of study that is growing in significance and importance within the academic, business, economic, and governmental realms. This study's main focus is on the changing retail environment with regards to business location and function within a small Midwestern city. The research focuses on Port Huron, Michigan because of the growth and shift of the retail community within the city over the past twenty years. The study specifically examines the changing influence and roles of Port Huron's central business district and of Birchwood Mall a retail development opened on the urban area's north end in 1990. The study uses the chi-squared, ANOVA, and cross tabulation statistical tests to analyze the changing geography of retail functions in the city. These statistics are used along with relative entropy equations to distinguish areas of high diversification, changing area functions, and common locations for multiple retail types.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc5187/
A Spatially Explicit Environmental Health Surveillance Framework for Tick-Borne Diseases
Date: August 2010
Creator: Aviña, Aldo
Description: In this paper, I will show how applying a spatially explicit context to an existing environmental health surveillance framework is vital for more complete surveillance of disease, and for disease prevention and intervention strategies. As a case study to test the viability of a spatial approach to this existing framework, the risk of human exposure to Lyme disease will be estimated. This spatially explicit framework divides the surveillance process into three components: hazard surveillance, exposure surveillance, and outcome surveillance. The components will be used both collectively and individually, to assess exposure risk to infected ticks. By utilizing all surveillance components, I will identify different areas of risk which would not have been identified otherwise. Hazard surveillance uses maximum entropy modeling and geographically weighted regression analysis to create spatial models that predict the geographic distribution of ticks in Texas. Exposure surveillance uses GIS methods to estimate the risk of human exposures to infected ticks, resulting in a map that predicts the likelihood of human-tick interactions across Texas, using LandScan 2008TM population data. Lastly, outcome surveillance uses kernel density estimation-based methods to describe and analyze the spatial patterns of tick-borne diseases, which results in a continuous map that reflects disease rates based ...
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc30432/
"I Speak, Therefore I Am:" Identity and Self-Construction as Motivation to Engage in Electronic Word of Mouth
Date: August 2010
Creator: Taylor, David George
Description: To paraphrase an old bromide, "you are what you consume." Consumers derive their sense of self through products, brands, performances and a host of other meaning-laden materials that they consume. The marketing literature has long recognized possessions as an extension of the self-concept. Although hundreds of studies have examined the linkage between consumption and the self, surprisingly few have examined a related phenomenon - the relationship between the self-concept and word of mouth (WOM). A handful of studies have demonstrated the use of WOM to enhance the consumer's self-image, but most extant research focuses on how the act of engaging in WOM is used to build the self-concept. To date there has not been an extensive examination of the process by which WOM transfers the meaning of a product, brand, advertisement or narrative from one consumer to another as part of identity construction. This dissertation attempts to answer the following research questions: 1. Do self-concept and identity motivate consumers to engage in electronic word-of-mouth (eWOM)? 2. Is there a conceptual model to represent the effects of message characteristics, product/brand characteristics and individual personality differences on the self-enhancement value of eWOM and resulting eWOM behaviors? A conceptual model was proposed and, ...
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc31549/
Speaking up! Adult ESL students' perceptions of native and non-native English speaking teachers.
Date: December 2004
Creator: Torres, Julie West
Description: Research to date on the native versus non-native English speaker teacher (NEST versus non-NEST) debate has primarily focused on teacher self-perception and performance. A neglected, but essential, viewpoint on this issue comes from English as a second language (ESL) students themselves. This study investigated preferences of adults, specifically immigrant and refugee learners, for NESTs or non-NESTs. A 34-item, 5-point Likert attitudinal survey was given to 102 students (52 immigrants, 50 refugees) enrolled in ESL programs in a large metropolitan area in Texas . After responding to the survey, 32 students volunteered for group interviews to further explain their preferences. Results indicated that adult ESL students have a general preference for NESTs over non-NESTs, but have stronger preferences for NESTs in teaching specific skill areas such as pronunciation and writing. There was not a significant difference between immigrants' and refugees' general preferences for NESTs over non-NESTs based on immigration status.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc4681/