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Texas Digital Newspaper Program
653
UNT Theses and Dissertations
460
Denton County Newspapers Collection
345
Denton Record-Chronicle
345
UNT Scholarly Works
151
The Suburbia News
53
Texas Jewish Post
52
The Monitor
48
Copperas Cove Leader Press
47
Texas Jewish Herald /Jewish Herald /Jewish Herald-Voice
42
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Libraries
100
Digital Projects Unit
55
College of Music
44
Department of Psychology
41
Department of Teacher Education and Administration
29
Department of Counseling and Higher Education
24
Department of Electrical Engineering
18
Department of English
18
Department of Biological Sciences
17
Department of History
17
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Evaluation Practices of Community College Faculty Development Programs
The purpose of this quantitative study was to determine the current state of community college faculty development program evaluation and identify possible influences on evaluation practices. Data from 184 survey responses and the Integrated Postsecondary Education Data System (IPEDS) were analyzed to answer three research questions. Multiple regression was used to determine if a relationship existed between the dependent/outcome variable (evaluation utilization score) and the independent/predictor variable (accrediting agency affiliation: MSCHE, NEASC, NCA, NWCCU, SACS, and WASC) and/or control variables (institution locale, student FTE, expenses per student FTE, percent spent on instruction, and percent of full-time faculty). Results were not statistically significant, F (12, 163) = 1.176, p = .305. The mean evaluation scores were similar for all six accrediting agencies ranging from 60-69. The rural variable was statistically significant with p = .003 and alpha = .05, but it only accounted for 3.6% of the variance explained. Logistic regression was used to determine if a relationship existed between the dependent/outcome variable (use of evaluation) and the above-specified independent/predictor variable and/or control variables for six faculty development program activities. Results revealed that significant predictor variables for the use of evaluation vary based on the faculty development program activity. Statistically significant …
Date:
December 2014
Creator:
Bunyard, Magen Lynn
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Evidence for Multiple Functions of a Medicago Truncatula Transporter
Legumes play an important role in agriculture as major food sources for humans and as feed for animals. Bioavailable nitrogen is a limiting nutrient for crop growth. Legumes are important because they can form a symbiotic relationship with soil bacteria called rhizobia that results in nitrogen-fixing root nodules. In this symbiosis, rhizobia provide nitrogen to the legumes and the legumes provide carbon sources to the rhizobia. The Medicago truncatula NPF1.7/NIP/LATD gene is essential for root nodule development and also for proper development of root architecture. Work in our lab on the MtNPF1.7/MtNIP/LATD gene has established that it encodes a nitrate transporter and strongly suggests it has another function. Mtnip-1/latd mutants have pleiotropic defects, which are only partially explained by defects in nitrate transport. MtNPF1.7/NIP/LATD is a member of the large and diverse NPF/NRT1(PTR) transporter family. NPF/NRT1(PTR) members have been shown to transport other compounds in addition to nitrate: nitrite, amino acids, di- and tri-peptides, dicarboxylates, auxin, abscisic acid and glucosinolates. In Arabidopsis thaliana, the AtNPF6.3/NRT1.1( CHL1) transporter was shown to transport auxin as well as nitrate. Atchl1 mutants have defects in root architecture, which may be explained by defects in auxin transport and/or nitrate sensing. Considering the pleiotropic phenotypes observed …
Date:
December 2014
Creator:
Huang, Ying-Sheng
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Exotic Femininity: Prostitution Reviews and the Sexual Stereotyping of Asian Women
Studies on prostitution have typically focused on the experiences, problems, and histories of prostitutes, rather than examining men who seek to purchase sex. Race has also been overlooked as a central factor in shaping the sex industry and the motivations of men who seek to purchase sex. This study utilizes online reviews of prostitutes to examine the way men who purchase sex discuss Asian prostitutes in comparison to White prostitutes. This paper traces the history of colonialism and ideas of the exotic Orient to modern stereotypes of Asian women. These stereotypes are then used to frame a quantitative and qualitative analysis of online reviews of prostitutes and compare the ways in which Asian prostitutes and white prostitutes are discussed. Further, the reviews are used to examine more broadly what services, traits, and behaviors are considered desirable by men who use prostitutes. The study finds that there are significant quantitative and qualitative differences in how men discuss Asian and White prostitutes within their reviews, and that these differences appear to be shaped by racially fetishizing stereotypes of Asian women. Prostitution also appears to reinforce male dominance and patriarchy in the form of masculine control and the feminine servicing of male sexual …
Date:
December 2014
Creator:
Dougherty, Devyn T.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Exploration of Visual, Acoustic, and Physiological Modalities to Complement Linguistic Representations for Sentiment Analysis
This research is concerned with the identification of sentiment in multimodal content. This is of particular interest given the increasing presence of subjective multimodal content on the web and other sources, which contains a rich and vast source of people's opinions, feelings, and experiences. Despite the need for tools that can identify opinions in the presence of diverse modalities, most of current methods for sentiment analysis are designed for textual data only, and few attempts have been made to address this problem. The dissertation investigates techniques for augmenting linguistic representations with acoustic, visual, and physiological features. The potential benefits of using these modalities include linguistic disambiguation, visual grounding, and the integration of information about people's internal states. The main goal of this work is to build computational resources and tools that allow sentiment analysis to be applied to multimodal data. This thesis makes three important contributions. First, it shows that modalities such as audio, video, and physiological data can be successfully used to improve existing linguistic representations for sentiment analysis. We present a method that integrates linguistic features with features extracted from these modalities. Features are derived from verbal statements, audiovisual recordings, thermal recordings, and physiological sensors signals. The resulting …
Date:
December 2014
Creator:
Pérez-Rosas, Verónica
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Exploring Factors That Lead to Perceived Instructional Immediacy in Online Learning Environments
Instructional communication research clearly indicates that instructor immediacy contributes significantly to effective instruction. However, the majority of immediacy studies have been conducted in traditional (face-to-face) classroom environments. More recently, instructional communication research has focused on assessing the impact of immediacy in online classroom environments. Again, immediacy appears to significantly contribute to effective instruction. The challenge is that most recent immediacy studies use immediacy measurements developed to test immediacy behaviors in face-to-face settings. Considering the lack of nonverbal communication and limited or absent synchronous or verbal communication in online instructional settings, the behaviors contributing most significantly to perceived immediacy, researchers need to reassess the immediacy construct in online environments. The present research explores and identifies behaviors reported by instructors to establish psychological closeness (i.e., immediacy) in online learning environments and assesses to what extent these behaviors are similar to or different from face-to-face immediacy-producing behaviors.
Date:
December 2014
Creator:
Spiker, Chance W.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Exploring Naming Behavior in Personal Digital Image Collections: the Iconology and Language Games of Pinterest
As non-institutional digital image collections expand into social media, independent non-professional image curators are emerging, actively constructing alternative naming conventions to suit their needs in a social collecting environment. This project considers how independent user-curators are developing particular sense-making behaviors as they actively contribute names to large, unstructured social image collections. In order to capture and explore this evolving language adaptation, Pinterest names are analyzed using a matrix composed of Panofsky’s three strata of subject matter, Rosch’s levels of categorical abstraction, Shatford Layne’s image attributes and Wittgenstein’s language game constructions. Analyzing Pinterest image names illuminates previously unnoticed behaviors by independent user-curators as they create shared collections. Exploring the various language choices which user-curators select as they apply this new curating vocabulary helps identify underlying user needs not apparent in traditionally curated collections restricted to traditional naming conventions.
Date:
December 2014
Creator:
Sutcliffe, Tami
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Factors Impacting the Accuracy of Self-report Perceptions of Expertise in Technology Integration
The focus of this study is to determine how closely self-report perceptions of technology integration skills align with the observations of an external evaluator. Participants were elementary and secondary teachers in a north Texas school district. The district is in the process of implementing a one-to-one initiative using a major vendor’s tablet devices. The study utilized both quantitative survey methodology, and a qualitative observational tool to record learning activities in the K-12 classroom. For the quantitative phase, three validated single-item self-report instruments were administered to the teachers via an online survey; the instruments utilized were the Concerns-Based Adoption Model—Levels of Use (CBAM-LoU); Stages of Adoption of Technology; and the Apple Classroom of Tomorrow (ACOT). In the qualitative portion of the study, classroom teachers involved in the one-to-one innovation were observed and rated by the Technology Integration Matrix, an instrument specifically designed to observe technology integration skills and practices in K-12 instructional settings. Kendall’s tau correlations between the various self-report instruments and the external observer rating are: CBAM, r = .51 (p is not significant); Stages, r = .58 (p < .05); ACOT, r = .82 (p < .01). Additionally, regression models were run using all three self-reports as predictors of …
Date:
December 2014
Creator:
Mayes, Garry W.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Faculty Attitudes Towards Institutional Repositories
The purpose of the study was to explore faculty attitudes towards institutional repositories in order to better understand their research habits and preferences. A better understanding of faculty needs and attitudes will enable academic libraries to improve institutional repository services and policies. A phenomenological approach was used to interview fourteen participants and conduct eight observations to determine how tenure-track faculty want to disseminate their research as well as their attitudes towards sharing research data. Interviews were transcribed and coded into emerging themes. Participants reported that they want their research to be read, used, and to have an impact. While almost all faculty see institutional repositories as something that would be useful for increasing the impact and accessibility of their research, they would consider publishers’ rights before depositing work in a repository. Researchers with quantitative data, and researchers in the humanities are more likely to share data than with qualitative or mixed data, which is more open to interpretation and inference. Senior faculty members are more likely than junior faculty members to be concerned about the context of their research data. Junior faculty members’ perception’ of requirements for tenure will inhibit their inclination to publish in open access journals, or share …
Date:
December 2014
Creator:
Hall, Nathan F.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Glass Forming Ability, Magnetic Properties, and Mechanical Behavior of Iron-Based and Cobalt-Based Metallic Glasses
Lack of crystalline order and microstructural features such as grain/grain-boundary in metallic glasses results in a suite of remarkable attributes including very high strength, close to theoretical elasticity, high corrosion and wear resistance, and soft magnetic properties. In particular, low coercivity and high permeability of iron and cobalt based metallic glass compositions could potentially lead to extensive commercial use as magnetic heads, transformer cores, circuits and magnetic shields. In the current study, few metallic glass compositions were synthesized by systematically varying the iron and cobalt content. Thermal analysis was done and included the measurement of glass transition temperature, crystallization temperature, and the enthalpies of relaxation and crystallization. Magnetic properties of the alloys were determined including saturation magnetization, coercivity, and Curie temperature. The coercivity was found to decrease and the saturation magnetization was found to increase with the increase in iron content. The trend in thermal stability, thermodynamic properties, and magnetic properties was explained by atomic interactions between the ferromagnetic metals and the metalloids atoms in the amorphous alloys. Mechanical behavior of iron based metallic glasses was evaluated in bulk form as well as in the form of coatings. Iron based amorphous powder was subjected to high power mechanical milling and …
Date:
December 2014
Creator:
Veligatla, Medha
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Growth Mechanisms, and Mechanical and Thermal Properties of Junctions in 3D Carbon Nanotube-Graphene Nano-Architectures
Junctions are the key component for 3D carbon nanotube (CNT)-graphene seamless hybrid nanostructures. Growth mechanism of junctions of vertical CNTs growing from graphene in the presence of iron catalysts was simulated via quantum mechanical molecular dynamics (QM/MD) methods. CNTs growth from graphene with iron catalysts is based on a ‘‘base-growth’’ mechanism, and the junctions were the mixture of C-C and Fe-C covalent bonds. Pure C-C bonded junctions could be obtained by moving the catalyst during CNT growth or etching and annealing after growth. The growth process of 3D CNT-graphene junctions on copper templates with nanoholes was simulated with molecular dynamic (MD) simulation. There are two mechanisms of junction formation: (i) CNT growth over the holes that are smaller than 3 nm, and (ii) CNT growth inside the holes that are larger than 3 nm. The growth process of multi-layer filleted CNT-graphene junctions on the Al2O3 template was also simulated with MD simulation. A simple analytical model is developed to explain that the fillet takes the particular angle (135°). MD calculations show that 135° filleted junction has the largest fracture strength and thermal conductivity at room temperature compared to junctions with 90°,120°, 150°, and 180° fillets. The tensile strengths of the …
Date:
December 2014
Creator:
Niu, Jianbing
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
A Historical Study of the Paris Small Business Development Center in Paris, Texas: 1986-2006
This historical study chronicled events of the development and implementation of the Paris Small Business Development Center at Paris Junior College in Paris, Texas from 1986-2006. Data was collected from primary and secondary sources and oral histories through personal interviews. The analysis included a brief history of higher education and the service mission and situated the study in the broader context as an extension program in higher education. This study provided a brief history of the U.S. Small Business Administration and America’s Small Business Development Center Network as a background for the study. This study is significant to scholars in the field of higher education for a number of reasons. It provides a historical analysis of a service program that extends the college to the community and demonstrates higher education and its role in economic development. It adds to the current body of research by advancing an understanding of a past to contemporary knowledge. Finally, by integrating historical perspectives from multiple disciplines in higher education, what happened and the context in which it happened can be more fully appreciated. This study also contributes to practical knowledge as it deepens the understanding of significant events and processes that contributed to the …
Date:
December 2014
Creator:
Smith, Donna Gayle
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Impact of Developmental Stress on Cardiovascular Physiology of Two Archosaur Species: American Alligator (Alligator mississippiensis) and Domestic Chicken (Gallus gallus)
Crocodilians and birds comprise sister taxa of archosaurs, the development of these vertebrates occurs within an egg case that leaves developing embryos susceptible to fluctuations in the nesting environment. Studies suggest that sub-optimal conditions alter morphological growth and cardiovascular physiology. Regulation of the cardiovascular system is immature in the subjects studied, and embryos may rely on humoral rather than neural control of the cardiovascular system. The primary focus of this dissertation was to assess regulatory mechanisms responsible for maintenance of arterial pressure and heart rate. Dehydration stress had marked effects on embryo growth, and altered baseline cardiovascular parameters, while leaving the response to humoral regulator, angiotensin II (Ang II), unaffected. However, dehydrated alligator embryos developed cholinergic tone on heart rate. Hypoxic incubated chicken embryos were reduced in embryo mass, and altered response to humoral regulatory components Ang I and adenosine in addition identifying a novel regulatory component of the cardiovascular response to acute hypoxia. Collectively, these studies add to the existing knowledge of cardiovascular physiology in embryonic archosaurs and suggest that some components of cardiovascular regulation are plastic following developmental stress.
Date:
December 2014
Creator:
Tate, Kevin B.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Impact of School-Wide Positive Behavior Intervention Supports for African American Males in American Public Schools
Research has shown that African American males are performing poorly in American public schools and are disciplined at a higher rate than other ethnic and gender groups. Positive Behavior Intervention Supports (PBIS) has a long history of success with individual students and more recently in school-wide settings. School-wide PBIS offers schools the ability to tailor their rules, rewards, and consequences to the specific needs and culture of a school. This descriptive and quantitative study sought to determine if implementation with fidelity of SWPBIS positively correlated to reduced disciplinary measures. The object of this study was to determine in what ways disciplinary rates for African American males differ in American public schools that identify as using SWPBIS with fidelity as compared to American public schools that do not implement SWPBIS with fidelity. Disciplinary rates examined included ISS, OSS single incident, and OSS multiple incidents. Descriptive findings indicated that schools that implement SWPBIS show a lower rate of ISS and OSS incidents for African American males. The quantitative findings did not yield a statistically significance between schools with fidelity of implementation of SWPBIS and schools without fidelity of implementation of SWPBIS.
Date:
December 2014
Creator:
Luttrull, Pamelia D.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
In-service Teacher Perception of Feedback From Formative Evaluation Within the Teacher Appraisal Process and Its Relationship to Teacher Self-efficacy
The purpose of the study is to describe the current status of and the relationships between teacher self-efficacy and in-service teachers’ perceptions and/or attitudes of (a) the quantity and quality of feedback from formative evaluation, (b) toward feedback from formative evaluation, and (c) the impact of feedback from formative evaluation on teacher self-efficacy. In addition to calculating correlation coefficients, 6 teachers were interviewed – 2 each from high, medium, and low efficacy schools. The quantitative data reported low, positive correlations between all of the factors. Statistically significant correlations were found between 8 of the 12 factors including teacher attitudes toward feedback from formative evaluation and: overall Teacher Sense of Efficacy Scale (r = .302), student engagement (r = .309), instructional strategies (r = .237) and classroom management (r =.266). Other statistically significant correlations were found between teacher perceptions of the impact of feedback from formative evaluation and its relationship to self-efficacy and: overall Teachers’ Sense of Efficacy Scale (r = .295), Student Engagement (r = .300), Instructional Strategies (r = .209), and Classroom Management (r = .282). The face-to-face interviews and online focus group supported the quantitative findings as the participants reported that they value formative evaluation and feedback and …
Date:
December 2014
Creator:
Curran, Chaney L.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
In Vitro Investigations of Antibiotic Influences on Nerve Cell Network Responses to Pharmacological Agents
Neuronal networks, derived from mouse embryonic frontal cortex (FC) tissue grown on microelectrode arrays, were used to investigate effects of gentamicin pretreatment on pharmacological response to the L-type calcium channel blocker, verapamil. Gentamicin is a broad spectrum antibiotic used to control bacterial contamination in cell culture. The addition of gentamicin directly to medium affects the pharmacological and morphological properties of the cells in culture. A reproducible dose response curve to verapamil from untreated cultures was established and the mean EC50 was calculated to be 1.5 ± 0.5 μM (n=10). 40 μM bicuculline was added to some cell cultures to stabilize activity and verapamil dose response curves were performed in presence of bicuculline, EC50 1.4 ± 0.1 μM (n=9). Statistical analysis showed no significant difference in verapamil EC50s values obtained in presence of bicuculline and hence the data was combined and a standard verapamil EC50 was calculated as 1.4 ± 0.13 μM (n=19). This EC50 was then used to compare verapamil EC50s obtained from neuronal cell cultures with chronic and acute exposures to gentamicin. FC cultures (21- 38 days old) were found to be stable in presence of 2300 μM gentamicin. The recommended concentration of gentamicin for contamination control is 5uL …
Date:
December 2014
Creator:
Sawant, Meera
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Influence of Engagement with Graphic Narrative Text Formats on Student Attitudes Towards the School Library
Comics, graphic novels, and manga differ appreciably from textual narrative formats, and materials with increasingly visual elements have found their way into progressive and student-centered library collections. But many educators and librarians still resist inclusion of graphic narratives in school libraries and devalue the reading practice of students who prefer more visual texts. Using the framework of radical change, which posits that both text conventions and reader expectations for text are increasingly multimodal as they possess characteristics of evolving digital media, this study considered the relationship of the characteristics of text individual students prefer, particularly those they select from the school library, and their attitudes towards aspects of reading practice as evidenced through the Adolescent Motivation to Read Profile instrument. Survey data was supplemented with circulation history from the library management system to inform a correlational study punctuating attitudinal differences based on reader preferences. Findings include high school students who engage with graphic narrative text formats reporting more favorable views of libraries and reading. There is a demonstrable distinction in attitudes between students who prefer more visual text when compared with peers with more traditional print affinities. Student engaging with graphic narrative texts also report more frequent engagement with text …
Date:
December 2014
Creator:
Stephens, Wendy Steadman
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Influence of Norwegian Folk Elements on Thomas Dyke Tellefsen’s Mazurkas Op 3 (1849) and Op 14 (1853)
Although Thomas Dyke Tellefsen’s mazurkas have been considered mere imitations of Chopin’s musical idiom, his mazurkas are closely related to Norwegian folk elements. Tellefsen adopted Norwegian folkloric elements from his own country and infused Norwegian spirit into his works to create his own musical language. To trace the Norwegian folk influence, this study examines folk dance (the springar), folk instruments (the hardanger fiddle and the langeleik), and folk melodic and rhythmic motifs. As the result, this research demonstrates that Tellefsen’s mazurkas were influenced by a phrase structure of Norwegian springar dance music and the exact sound effect of folk instruments (the hardanger fiddle and the langeleik) as well as Norwegian folk rhythmic and melodic formulas which are frequently used in Norwegian folk tunes. Furthermore, the comparison between Tellefsen and Chopin’s mazurkas demonstrates that although their mazurkas seem to have a similar musical style, Tellefsen’s mazurkas include his own traditional Norwegian folk aesthetic, which present original contributions to the genre.
Date:
December 2014
Creator:
Lim, Mikyung
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Influence of Surface Roughness and Its Geometry on Dynamic Behavior of Water Droplets
In this study the author reports the effects of surface roughness on dynamic behavior of water droplets on different types of rough structures. First, the influence of roughness geometry on the Wenzel/ Cassie-Baxter transition of water droplets on one-tier (solid substrates with Si micropillars) surfaces is studied (Chapter 3). In order to address distinct wetting behaviors of the advancing and receding motions, the author investigates the Wenzel/ Cassie-Baxter transition of water droplets on one-tier surfaces over a wide range of contact line velocities and droplet volumes in both advancing and receding movements. The discussions are strengthened by experimental results. According to the author’s analysis, the advancing contact zone tends to follow the Cassie-Baxter behavior for a wider range of geometric ratios than the receding contact zone. Physical phenomena such as advancing contact line rolling mechanism and the pinning of the receding contact line are introduced to justify distinct transition points of the advancing and receding movements respectively. Based on the analysis provided in Chapter 3, the author experimentally investigates the contact line fluctuations and contact line friction coefficients of water droplets on smooth, one-tier, and two-tier (with carbon nanotubes (CNTs) grown on Si micropillars) surfaces in Chapters 4 and 5. …
Date:
December 2014
Creator:
Sadeghpour, Nima.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Interaction of Plasmons and Excitons for Low-Dimension Semiconductors
The effects of surface plasmon for InGaN/GaN multi-quantum wells and ZnO nanoparticles optical linear and nonlinear emission efficiency had been experimentally studied. Due to the critical design for InGaN MQWs with inverted hexagonal pits based on GaN, both contribution of surface plasmon effect and image charge effect at resonant and off resonant frequencies were experimentally and theoretically investigated. With off- resonant condition, the InGaN MQWs emission significantly enhanced by metal nanoparticles. This enhancement was caused by the image charge effect, due to the accumulation of carriers to NPs region. When InGaN emission resonated with metal particles SP modes, surface Plasmon effect dominated the emission process. We also studied the surface plasmon effect for ZnO nanoparticles nonlinear optical processes, SHG and TPE. Defect level emission had more contribution at high incident intensity. Emissions are different for pumping deep into the bulk and near surface. A new assumption to increase the TPE efficiency was studied. We thought by using Au nanorods localized surface plasmon mode to couple the ZnO virtual state, the virtual state’s life time would be longer and experimentally lead the emission enhancement. We studied the TPE phenomena at high and near band gap energy. Both emission intensity and decay …
Date:
December 2014
Creator:
Lin, Jie (physicist)
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
The Interactive Effects of Tax and Expenditure Limitations Stringency with Revenue Diversity and the Council-manager Form of Government on Municipal Expenditures
This dissertation examines the effects of tax and expenditure limitations (TELs) stringency and its interaction with revenue diversity and the council-manager form of government on municipal general fund expenditure. TELs are explicit rules that states impose to reduce local government spending. TELs stringency varies from state to state, leading to difficulties in assessing their impact across the nation. This dissertation proposes a new means for measuring the stringency of TELs imposed on local governments. Factor analysis is utilized, and then factor scores are calculated to identify degrees of TELs stringency. This study contends that higher levels of TELs stringency are associated with lower local government spending. However, the effectiveness of TELs is dependent on revenue diversity and the form of government. This study suggests that both revenue diversity and the council-manager form of government mitigate the impacts of TELs stringency on local government spending. Panel data from 2007 to 2011 from 1,508 municipalities are utilized. This study finds that higher levels of TELs stringency are associated with lower levels of municipal general fund expenditures per capita. However, TELs stringency is effective only when revenue diversity is low and when cities have a form of government other than council-manager. These results …
Date:
December 2014
Creator:
Jaikampan, Kraiwuth
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Investigating the Ability of Pseudomonas aeruginosa pyrE Mutants to Grow and Produce Virulence Factors
Pseudomonas aeruginosa are medically important bacteria that are notorious for causing nosocomial infections. To gain more knowledge into understanding how this organism operates, it was decided to explore the pyrimidine biosynthetic pathway. Pyrimidine synthesis, being one half of the DNA structure, makes it a very important pathway to the organism’s survivability. With previous studies being done on various genes in the pathway, pyrE has not been studied to the fullest extent. To study the function of pyrE, a site directed mutagenesis was done to completely knock out pyrE, which encodes the protein orotate phosphoribosyl transferase that is responsible for converting orotate into orotate monophosphate (OMP). A mutation in this step leads to accumulation and secretion of orotate into the medium. Analyzing virulence factors produced by the mutant and comparing to the wild type, some intriguing features of the mutant were discovered. One of the findings was the over expression of virulence factors pyoverdin and pyocyanin. Pyocyanin over expression, based on the results of this study, is due to the accumulation of orotate while over production of pyoverdin is due to the accumulation of dihydroorotate. The other virulence factors studied were motility assays, exoproducts, and growth analysis. All virulence factor production …
Date:
December 2014
Creator:
Niazy, Abdurahman
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Kinetic Investigation of Atomic Hydrogen with Sulfur-Containing Species
The reactions of atomic hydrogen with methanethiol and that of atomic hydrogen with carbon disulfide were studied experimentally using flash-photolysis resonance-fluorescence techniques. Rate constants were determined over a range of temperatures and pressures, and through analysis and comparison to theoretical work details of the reactions were ascertained.
Date:
December 2014
Creator:
Kerr, Katherine Elaine
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Kinetic Studies on C‐h Bond Activation in the Reaction of Triosmium Clusters with Diphosphine and Amidine Ligands
The reaction of 1-(diphenylphosphino)-2-(diphenylphosphito)benzene (PP*) and Os3(CO)10(ACN) has been investigated. A combined experimental and computational study on the isomerization of 1,2-Os3(CO)10[μ-1,2-Ph2P(C6H4)P(OPh)2] (A) and 1,1-Os3(CO)10[μ-1,2-Ph2P(C6H4)P(OPh)2] (B) and reversible ortho-metalation exhibited by the triosmium cluster B are reported. The subsequent conversion of cluster B to the hydrido cluster HOs3(CO)9[μ-1,2-PhP(C6H4-η1)C6H4P(OPh)2] (E) and the benzyne-substituted cluster HOs3(CO)8(µ3-C6H4)[μ-1,2-PhP(C6H4)P(OPh)2] (N) has been established. All of these new clusters have been isolated and fully characterized in solution by IR and NMR spectroscopy; in addition, X-ray diffraction analyses have been performed on the clusters A, B, J, and N. The ortho-metalation reaction that gives cluster E is shown to be reversible, and the mechanism has been probed using selectively deuterated PP* isotopomers. Kinetic and thermodynamic isotope data, in conjunction with DFT calculations, are presented that support the existence of an intermediate unsaturated cluster in the ortho-metalation reaction. Due to interest in the coordination chemistry of formamidines, the non-symmetric amidine ligands PhNC(Me)NHPri, PhNC(Et)NHPri, and (2,4,6-Me3C6H2)NC(Me)NHPri, have been synthesized, and their reaction with Os3(CO)10(MeCN)2 has been investigated. Of the twelve new clusters prepared in section, seven have been structurally characterized by X-ray crystallography.
Date:
December 2014
Creator:
Yang, Li
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Laser Surface Alloying of Refractory Metals on Aluminum for Enhanced Corrosion Resistance: Experimental and Computational Approaches
Aluminum (Al) and its alloys are widely used in various technological applications, mainly due to the excellent thermal conductivity, non-magnetic, ecofriendly, easy formability and good recyclability. However due to the inferior corrosion resistance its applications are hampered in various engineering sectors. Besides, the corrosion related failures such as leakage of gas from pipeline, catastrophic breakdown of bridges and fire accidents in processing plants further puts the human life in jeopardy. Within the United States over $ 400 billion dollars per year are spent over research to understand and prevent the corrosion related failures. Recently, the development of transition metal(TM) aluminides (AlxTMy, where, TM = Mo, W, Ta, Nb, Cr, Zr and V) has received the global attention mainly due to high strength at elevated temperatures, light-weight, excellent corrosion and wear resistance. In light of this, surface modification via laser surface alloying (LSA) is a promising engineering approach to mitigate the corrosion and wear problems. In the present study the attempts are made to study the Al-Mo, Al-W, Al-Nb, and Al-Ta systems as a potential corrosion resistant coatings on aluminum. The refractory metal (Mo, W, Nb, Ta) precursor deposit was spray coated separately on aluminum substrate and was subsequently surface alloyed …
Date:
December 2014
Creator:
Rajamure, Ravi Shanker
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library