Degree Level

States

Language

142 Matching Results

Results open in a new window/tab.

Acculturation Level, Generational Status and Gender: Their Role in Acculturative Stress in Young Adolescent Mexican Americans (open access)

Acculturation Level, Generational Status and Gender: Their Role in Acculturative Stress in Young Adolescent Mexican Americans

The purpose of this study was to determine relationships between acculturation level, generational status, and gender with acculturative stress. Acculturation level was determined by the Acculturation Rating Scale for Mexican Americans-II (ARSMA-II) and acculturative stress was determined by the Societal, Attitudinal, Familial and Environmental Acculturative Stress Scale-Children's Version (SAFE-C). Subjects included 1268 Hispanic children ages 11-15. In order to validate the usefulness of the ARSMA-II with this sample, analyses were conducted between acculturation level and generational status. The Pearson product moment correlation (r=.44) and the ANOVA between the mean acculturation score and generational status were significant. However, the mean acculturation score from this study was considerably lower than the ARSMA-II score; therefore, new acculturation levels were developed to establish local adolescent norms for the ARSMA-II. All analyses involving acculturation levels were conducted using both the ARSMA-II and new acculturation levels because 300 subjects were reclassified with the new norms. Significant results were similar using both acculturation levels; however, there were more between group differences using the new acculturation levels. It was hypothesized that as acculturation level increased toward the Anglo culture, acculturative stress would decrease. The one-way ANOVA confirmed this relationship. It was also hypothesized that as generational status increased, …
Date: August 2004
Creator: Manning, Suzanne C.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
N-Acylethanolamine Metabolism During Seed Germination: Molecular Identification of a Functional N-Acylethanolamine Amidohydrolase (open access)

N-Acylethanolamine Metabolism During Seed Germination: Molecular Identification of a Functional N-Acylethanolamine Amidohydrolase

N-Acylethanolamines (NAEs) are endogenous lipid metabolites that occur in a variety of dry seeds, and their levels decline rapidly during the first few hours of imbibition (Chapman et al., 1999, Plant Physiol., 120:1157-1164). Biochemical studies supported the existence of an NAE amidohydrolase activity in seeds and seedlings, and efforts were directed toward identification of DNA sequences encoding this enzyme. Mammalian tissues metabolize NAEs via an amidase enzyme designated fatty acid amide hydrolase (FAAH). Based on the characteristic amidase signature sequence in mammalian FAAH, a candidate Arabidopsis cDNA was identified and isolated by reverse transcriptase-PCR. The Arabidopsis cDNA was expressed in E. coli and the recombinant protein indeed hydrolyzed a range of NAEs to free fatty acids and ethanolamine. Kinetic parameters for the recombinant protein were consistent with those properties of the rat FAAH, supporting identification of this Arabidopsis cDNA as a FAAH homologue. Two T-DNA insertional mutant lines with disruptions in the Arabidopsis NAE amidohydrolase gene (At5g64440) were identified. The homozygous mutant seedlings were more sensitive than the wild type to exogenously applied NAE 12:0. Transgenic seedlings overexpressing the NAE amidohydrolase enzyme showed noticeably greater tolerance to NAE 12:0 than wild type seedlings. These results together provide evidence in vitro …
Date: August 2004
Creator: Shrestha, Rhidaya
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Adapting Filial Therapy for Families who have a Child with a Life-Threatening Illness (open access)

Adapting Filial Therapy for Families who have a Child with a Life-Threatening Illness

Utilizing a collective case study design, I examined and described the filial therapy (FT) process and adaptations discovered to be necessary and unnecessary in working with families who have a child with a life-threatening illness in the hospital setting. Data from a total of 7 parents was utilized, including those who terminated early, in order to gain a greater understanding of adapting FT for families who have a child with a life-threatening illness and their participation patterns. The parents attended 10 one- to two-hour FT sessions. The data was analyzed to examine for themes, patterns and relationships intrinsically with each case participant, as well as across cases. Analysis indicated that parents with a child with a life-threatening illness had great difficulty committing to attend FT; and a high rate of attrition occurred for those who did commit. A theme regarding flexibility was found to be of eminent importance in a variety of manifestations including therapeutic methods, session format, location and time of sessions, and intense vs traditional FT. Therapeutic adaptations in flexibility found to be important including openness to cathartic and personal parenting sessions, tolerance of forgetfulness, and lowering typical therapeutic concerns of dependency in the relationship. An inability for …
Date: August 2004
Creator: Steen, Rheta LeAnne
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Adaptive Planning and Prediction in Agent-Supported Distributed Collaboration. (open access)

Adaptive Planning and Prediction in Agent-Supported Distributed Collaboration.

Agents that act as user assistants will become invaluable as the number of information sources continue to proliferate. Such agents can support the work of users by learning to automate time-consuming tasks and filter information to manageable levels. Although considerable advances have been made in this area, it remains a fertile area for further development. One application of agents under careful scrutiny is the automated negotiation of conflicts between different user's needs and desires. Many techniques require explicit user models in order to function. This dissertation explores a technique for dynamically constructing user models and the impact of using them to anticipate the need for negotiation. Negotiation is reduced by including an advising aspect to the agent that can use this anticipation of conflict to adjust user behavior.
Date: December 2004
Creator: Hartness, Ken T. N.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Adherence/Diffusion Barrier Layers for Copper Metallization: Amorphous Carbon:Silicon Polymerized Films (open access)

Adherence/Diffusion Barrier Layers for Copper Metallization: Amorphous Carbon:Silicon Polymerized Films

Semiconductor circuitry feature miniaturization continues in response to Moore 's Law pushing the limits of aluminum and forcing the transition to Cu due to its lower resistivity and electromigration. Copper diffuses into silicon dioxide under thermal and electrical stresses, requiring the use of barriers to inhibit diffusion, adding to the insulator thickness and delay time, or replacement of SiO2 with new insulator materials that can inhibit diffusion while enabling Cu wetting. This study proposes modified amorphous silicon carbon hydrogen (a-Si:C:H) films as possible diffusion barriers and replacements for SiO2 between metal levels, interlevel dielectric (ILD), or between metal lines (IMD), based upon the diffusion inhibition of previous a-Si:C:H species expected lower dielectric constants, acceptable thermal conductivity. Vinyltrimethylsilane (VTMS) precursor was condensed on a titanium substrate at 90 K and bombarded with electron beams to induce crosslinking and form polymerized a-Si:C:H films. Modifications of the films with hydroxyl and nitrogen was accomplished by dosing the condensed VTMS with water or ammonia before electron bombardment producing a-Si:C:H/OH and a-Si:C:H/N and a-Si:C:H/OH/N polymerized films in expectation of developing films that would inhibit copper diffusion and promote Cu adherence, wetting, on the film surface. X-ray Photoelectron Spectroscopy was used to characterize Cu metallization of …
Date: May 2004
Creator: Pritchett, Merry
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Age and Responses to the Events of September 11, 2001 (open access)

Age and Responses to the Events of September 11, 2001

Following the terrorist attacks on the United States on September 11, 2001, many turned to the field of psychology for greater understanding of the impact of such events and guidance in supporting our citizens. This study sought to gain greater understanding of the differential impact of the September 11th attack on individuals by investigating the influence of age, psychological hardiness, and repression versus sensitization as forms of coping behavior on psychological health. Both an initial cross-sectional sample (172 young adults & 231older adults) and a short-term longitudinal follow-up (39 young adults & 58 older adults) were included in the study. Older age, psychological hardiness and the use of a repressing coping style were found to each individually relate to greater resilience/less dysfunction at both time one and two. For young adults, high hardy repressors faired best, followed by high hardy sensitizers. Low hardy young adults demonstrated similar levels of dysfunction regardless of coping style (repressions/sensitization). For older adults, coping style impacted both high and low hardy individuals equally, with high hardy repressors demonstrating greater functioning. This study attempted to gain greater insight into explanations for these and previous findings of greater resilience among older adults. In explaining the greater resilience …
Date: December 2004
Creator: Holmes, D. Nicole
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Analysis of Advisory Committee Activities in a Successful Public School Bond Election (open access)

An Analysis of Advisory Committee Activities in a Successful Public School Bond Election

The purpose of this study was to determine the perceived effectiveness of specific advisory committee activities during a school bond proposal and election process. The study began with an extensive review of the literature on the use of advisory committee activities in school districts for the purpose of promoting a school bond issue. This revealed that school officials maintaining a low profile, the presence of a diverse community task force, focusing on YES voters, involving the committee in early planning, focusing on disseminating information, and focusing on benefits to children and the community are all important in the passage of a school bond election. A survey was developed and administered to committee members, school board members and school district administrators in a North Texas school district that had successfully completed a bond election. Survey respondents consistently supported the practices put into place by the studied school district, which closely mirrored the activities espoused in the research. Respondents believed the diversity of the task force and the roles of the committee members to be crucial to the passage of the bond. The only subcategory of questions that drew mixed reviews and positions of support was that of the need for the …
Date: August 2004
Creator: Waters, Philo W.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Analysis of Leadership Perceptions Using Multirater Feedback. (open access)

Analysis of Leadership Perceptions Using Multirater Feedback.

Performance improvement intervention begins with assessment. How that assessment is interpreted can mean the difference between success and failure. Previous research of 360-degree feedback instruments has tried to reconcile the differences between multiple rater groups. Rather than searching for agreement, this research proposes to understand the meaning of the differences using multirater feedback. Individuals determine ratings based upon their own perspective and building upon the understanding of rater perspective may result in improved assessments. Data from an existing data set was processed using a second-order CFA in structural equation modeling. Covariance between the second-order factors and rater groups determined the difference in how each rater group perceived the leader.
Date: May 2004
Creator: Bradley, Thomas P.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Analysis of Perceptional Differences Among Department Chairs, Faculty, and Instructors Toward the Barrier to Using Multiple Teaching Strategies in Two-Year Technical and Community College Electronics Courses (open access)

Analysis of Perceptional Differences Among Department Chairs, Faculty, and Instructors Toward the Barrier to Using Multiple Teaching Strategies in Two-Year Technical and Community College Electronics Courses

The purpose of this study was to identify and analyze perceptional differences among department chairs, faculty, and instructors toward the barrier to using multiple teaching strategies in two-year technical and community college electronics courses. The literature review focused on defining multiple teaching strategies and identifying and discussing four major perceived barriers to implementing them in the electronics classroom: student, resources, classroom environmental, and teacher training/teaching technology. The targeted population consisted of 150 out of 231 electronics teaching technical and community college department chairs, faculty, and instructors throughout the state of Texas. In actuality, the targeted population's breakdown consisted of 36 full-time electronics teaching department chairs, 96 full-time electronics teaching faculty and instructors, and 18 part-time electronics teaching faculty and instructors who were actively involved in the delivery of instruction in their respective schools. Analysis of the data revealed that: (1) there are no significant differences among the perceptions of department chair people, faculty, and instructors toward the four perceived barriers to implementing multiple teaching strategies in a post-secondary electronics program; and (2) there are no significant differences in the perceptions electronics faculty members categorized by years teaching experience toward each of the four perceived barrier categories to implementing multiple teaching …
Date: May 2004
Creator: Hutyra, Jerry Emil
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Analysis of the Effect of Distance Learning on Student Self-Efficacy of Junior High School Spanish Students. (open access)

An Analysis of the Effect of Distance Learning on Student Self-Efficacy of Junior High School Spanish Students.

Prior to the development of interactive television, schools that were either geographically isolated or financially restricted were often unable to provide courses that may have been essential for students. Interactive television has helped such school districts provide appropriate courses for their students. Because student self-efficacy is a significant indicator of student success, the relationship between distance learning and students' self-efficacy requires research. The problem of the study was to examine the impact of site location in a distance learning environment on student self-efficacy in Spanish instruction. The participants in this study were junior high school students enrolled in distance-learning Spanish classes at two junior high schools in a north central Texas independent school district. All of the students were taught by the same instructor. The age range of the students was from 11 to 14 years of age, and all students were in either the seventh or the eighth grade. Students took a modified version of the Motivated Strategies for Learning Questionnaire at the end of each treatment. Using the counterbalanced design, each subject was matched to themselves. T-tests for nonindependent samples were used to compare the two treatments. The findings indicate that there is no significant difference in the …
Date: August 2004
Creator: Vroonland, David W.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Analysis of the Genesis of Motive, Rhythm, and Pitch in the First Movement of the Sonata for Two Pianos and Percussion by Béla Bartók. (open access)

An Analysis of the Genesis of Motive, Rhythm, and Pitch in the First Movement of the Sonata for Two Pianos and Percussion by Béla Bartók.

This dissertation presents evidence that Béla Bartók created his masterwork, the Sonata for Two Pianos and Percussion (1937), in a very complex period of his life. Since it was a mature piece, Bartók utilized typically "Bartókian" compositional techniques and styles. His ethnomusicological studies were also influential factors in the creation of the Sonata for Two Pianos and Percussion. We can be witness to how different the first draft was to the published version; the minor and major changes are revealed in the draft study of the Sonata for Two Pianos and Percussion 's first movement. These changes allow today's musicians to reconstruct the compositional process. The first movement introduces some interesting uses of sonata form, to be explored in more detail in the analysis. Starting with linear analysis, the basic motives and rhythmic patterns are discussed and supported with Bartók's own explanations. The conclusion of this study has important ramifications for performance: it eases up the pressure on the performers, since problematic passages are analyzed and explained - preparing the players' mentally for the performance. This is music which is hard to play and difficult to analyze. The analysis, combining the results of both theoretical and musicological studies, is intended …
Date: May 2004
Creator: Ujj-Hilliard, Emöke
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Anatomy of Academic Dishonesty: Cognitive Development, Self-Concept, Neutralization Techniques, and Attitudes Toward Cheating (open access)

The Anatomy of Academic Dishonesty: Cognitive Development, Self-Concept, Neutralization Techniques, and Attitudes Toward Cheating

This study explored the relationship between cheating among university students and their cognitive developmental levels, use of neutralization techniques, self-concept as a multifaceted cognitive construct, and attitude toward cheating. The purposes of this study were to investigate: (1) The relationships between academic dishonesty and each of the following overall independent variables: cognitive development, use of neutralization techniques, self-concept as a multifaceted cognitive construct, and attitude toward cheating, and (2) the reasons behind college student academic cheating behaviors. The study used data from anonymous, self-report surveys administered to undergraduate students in-class and at supplemental sessions. Student participation was voluntary. The study was correlational. The five hypotheses were: (1) Self-concept is significantly and negatively related to academic dishonesty; (2) Cognitive development is significantly and negatively related to academic dishonesty; (3) Attitude toward cheating is significantly and negatively related to academic dishonesty; (4) The use of neutralization techniques is significantly and positively related to academic dishonesty; (5) Cognitive development, self-concept, and attitude toward cheating will make significant contributions to the regression model for the dependent variables of academic dishonesty. The data supported the first, third, and fourth hypotheses. However, the second and fifth hypotheses were supported under certain conditions. The roles of cognitive …
Date: August 2004
Creator: Arvidson, Cody Jean
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Appellate Recruitment Patterns in the Higher British Judiciary: 1850 - 1990 (open access)

Appellate Recruitment Patterns in the Higher British Judiciary: 1850 - 1990

This study seeks to advance the understanding of appellate promotion in the senior judiciary of Great Britain . It describes the population and attributes of judges who served in the British High Courts, Court of Appeal, and Appellate Committee of the House of Lords (i.e., Law Lords) from 1850 to 1990. It specifically builds upon the work of C. Neal Tate and tests his model of appellate recruitment on a larger and augmented database. The study determines that family status, previously asserted as having a large effect on recruitment to the appellate courts, is not as important as previously believed. It concludes that merit effects, professional norms, and institutional constraints offer equally satisfactory or better explanations of appellate recruitment patterns.
Date: December 2004
Creator: Thomas, Bruce K.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Application of Cultured Neuronal Networks for Use as Biological Sensors in Water Toxicology and Lipid Signaling.

Access: Use of this item is restricted to the UNT Community
This dissertation research explored the capabilities of neuronal networks grown on substrate integrated microelectrode arrays in vitro to be applied to toxicological research and lipid signaling. Chapter 1 details the effects of chlorine on neuronal network spontaneous electrical activity and pharmacological sensitivity. This study demonstrates that neuronal networks can maintain baseline spontaneous activity, and respond normally to pharmacological manipulations in the present of three times the chlorine present in drinking water. The findings suggest that neuronal networks may be used as biological sensors to monitor the quality of water and the presence of novel toxicants that cannot be detected by conventional sensors. Chapter 2 details the neuromodulatory effects of N-acylethanolamides (NAEs) on the spontaneous electrical activity of neuronal networks. NAEs are a group of lipids that can mimic the effects of marijuana and can be derived from a variety of plant sources including soy lecithin. The most prominent NAEs in soy lecithin, palmitoylethanolamide (PEA) and linoleoylethanolamide (LEA), were tested individually and were found to significantly inhibit neuronal spiking and bursting activity. These effects were potentiated by a mixture of NAEs as found in a HPLC enriched fraction from soy lecithin. Cannabinoid receptor-1 (CB1-R) antagonists and other cannabinoid pathway modulators indicated …
Date: August 2004
Creator: Dian, Emese Emöke
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Assessment of Technology Learning Styles, Skills, and Perceptions Among Teachers of Grades Pre-Kindergarten Through Four. (open access)

An Assessment of Technology Learning Styles, Skills, and Perceptions Among Teachers of Grades Pre-Kindergarten Through Four.

This study investigated whether a relationship exists between learning style and the self-reported technology-related needs, beliefs, stages of adoption, software expertise, and technology competencies of teachers in a large suburban school district. The Gregorc Style Delineator was used to identify dominant learning style, and the Snapshot Survey was used to measure technology-related needs, beliefs, stages of adoption, and software expertise. Technology competencies were measured using the Technology in Education Competency Survey. Data collected from 499 participants was included in data analysis. The study was conducted at each of the 12 elementary schools of a large suburban district in the Dallas-Fort Worth Metroplex. The findings suggest that there is a significant relationship between learning style and the technology-related needs, stages of adoption, software expertise, and competencies of teachers. The relationship between learning style and technology-related needs was significant at the p < .01 level. The relationships between learning style and technology-related stages of adoption, software expertise, and technology competencies were significant at the p < .05 level. Members of the abstract sequential [AS] learning style group reported having significantly fewer needs and significantly higher stages of adoption, software expertise, and competency than members of one or more of the other learning …
Date: December 2004
Creator: Brubaker, Douglas D.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Assessment of the Effectiveness of the CHAMPS/Life Skills Program at the University of North Texas: A Pilot Study (open access)

An Assessment of the Effectiveness of the CHAMPS/Life Skills Program at the University of North Texas: A Pilot Study

This study seeks to determine the effectiveness of the Challenging Athletes Minds for Personal Success (CHAMPS)/Life Skills program at the University of North Texas, as perceived by the student athletes who participate or participated in this program. The study attempts to measure the extent to which the student athletes feel that the program had value; if they received helpful information to support them through their college career to career transition; if the student athletes felt that the program provided them with skills to encourage better self-esteem; and if they believed that the CHAMPS/Life Skills program provided them with leadership and character education. The study, conducted in the Fall of 2003, had 163 respondents. An instrument was developed to determine student athletes' perceptions of the effectiveness of the CHAMPS/Life Skills program at UNT. The instrument consisted of 30 questions using a Likert-type scale. A Mann-Whitney U, a non-parametric t-Test, was utilized to analyze the data. This type of t-Test was used because it is specifically designed to compare the means of the same variable with two different groups and account for non-homogeneous groups. The lack of homogeneity was very likely influenced by the unequal group sizes. Generally, all aspects of the …
Date: May 2004
Creator: Goddard, Michael
Object Type: Thesis or Dissertation
System: The UNT Digital Library

An Assessment of the Use of Student Price Response Models to Predict Changes in Undergraduate Enrollment at a Metropolitan University

Access: Use of this item is restricted to the UNT Community
Most colleges and universities invest substantial resources in an effort to strategically plan for a sound financial base. The revenue for the financial base is dependent on student enrollment that must be effectively managed. Increases in the price of tuition and fees can lead to decreased enrollment and negatively impact the revenue of an institution. The increases can also impact the enrollment of certain student populations such as minority students and high school graduates enrolling in college for the first time. Many studies have analyzed the price elasticity and student price response models that have been developed over time by reviewing historical price increases and enrollment across institutions. Few studies have used the models to predict changes in the enrollment of students for one college or university after the increases in the cost of attendance are imposed on students. This study sought to analyze the effectiveness of the most commonly reviewed student price response and price elasticity models in predicting changes in undergraduate enrollment at one metropolitan academic university. The three models introduced by Leslie and Brinkman, St. John and Heller were used to analyze the tuition and fee increases and to identify the likely percentage of increase or decrease …
Date: December 2004
Creator: Saxon, Randall J.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Barrier and Long Term Creep Properties of Polymer Nanocomposites.

Access: Use of this item is restricted to the UNT Community
The barrier properties and long term strength retention of polymers are of significant importance in a number of applications. Enhanced lifetime food packaging, substrates for OLED based flexible displays and long duration scientific balloons are among them. Higher material requirements in these applications drive the need for an accurate measurement system. Therefore, a new system was engineered with enhanced sensitivity and accuracy. Permeability of polymers is affected by permeant solubility and diffusion. One effort to decrease diffusion rates is via increasing the transport path length. We explore this through dispersion of layered silicates into polymers. Layered silicates with effective aspect ratio of 1000:1 have shown promise in improving the barrier and mechanical properties of polymers. The surface of these inorganic silicates was modified with surfactants to improve the interaction with organic polymers. The micro and nanoscale dispersion of the layered silicates was probed using optical and transmission microscopy as well as x-ray diffraction. Thermal transitions were analyzed using differential scanning calorimetry. Mechanical and permeability measurements were correlated to the dispersion and increased density. The essential structure-property relationships were established by comparing semicrystalline and amorphous polymers. Semicrystalline polymers selected were nylon-6 and polyethylene terephthalate. The amorphous polymer was polyethylene terphthalate-glycol. Densification …
Date: December 2004
Creator: Ranade, Ajit
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Bioavailability and toxicity of 2,4,6-trinitrotoluene in sediment.

Access: Use of this item is restricted to the UNT Community
TNT (2,4,6-trinitrotoluene) is a persistent contaminant at many military installations and poses a threat to aquatic ecosystems. Data from environmental fate and toxicity studies with TNT revealed that sediment toxicity test procedures required modification to accurately assess sediment TNT toxicity. Key modifications included aging TNT-spiked sediments 8-14 d, basing lethal dose on measured sediment concentrations of the molar sum of TNT and its main nitroaromatic (NA) transformation products (SNA), basing sublethal dose on average sediment SNA concentrations obtained from integration of sediment SNA transformation models, avoiding overlying water exchanges, and minimizing toxicity test durations. Solid phase microextraction fibers (SPMEs) were investigated as a biomimetic chemical measure of toxicity and bioavailability. Both organism and SPME concentrations provided measures of lethal dose independent of exposure scenario (TNT-spiked sediment or TNT-spiked water) for Tubifex tubifex. Among all benthic organisms tested (Chironomus tentans, Ceriodaphnia dubia, T. tubifex) and matrixes, median lethal dose (LC50) estimates based on SPME and organism concentrations ranged from 12.6 to 55.3 mmol SNA/ml polyacrylate and 83.4 to 172.3 nmol SNA/g tissue, ww, respectively. For Tubifex, LC50s (95% CI) based on SNA concentrations in sediment and SPMEs were 223 (209-238) nmol SNA/g, dw and 27.8 (26.0-29.8) mmol SNA/ml, respectively. Reproductive effects …
Date: May 2004
Creator: Conder, Jason M.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Biogeography of Montane Mammals on the Colorado Plateau and Adjacent Regions

Access: Use of this item is restricted to the UNT Community
This study identifies the biogeographic factors that structure small mammal communities on mountains of the Colorado Plateau and adjacent regions. Forty six isolated ranges were characterized across a 5-state study area encompassing the Colorado Plateau, including the central high plateaus of Utah and the Basin and Range Province (i.e. the Great Basin and mountains of Arizona and New Mexico). Presence/absence data of 25 montane mammal species were used to explore the interactions between historical and ecological processes affecting local and regional diversity patterns. Multivariate analyses, such as non-metric dimensional scaling, were used to explore factors which influence community composition. Results of these analyses revealed the Colorado River as a significant biogeographic barrier that affects montane mammal community structure. MtDNA cytochrome b sequence variation was analyzed among populations of the long-tailed vole, Microtus longicaudus, sampled from five interior ranges of the Colorado Plateau- Abajo, LaSal, Henry, and Chuska Mts., and Boulder Mountain of the Aquarius Plateau-and analyzed using traditional phylogenetic approaches (parsimony and likelihood) as well as nested clade analysis. Results support previous documentation of a major east-west phylogeographic break occurring between populations southeast of the Colorado River (eastern Arizona, Colorado, Wyoming and New Mexico) and all other western populations, which …
Date: May 2004
Creator: Carr, Carla B.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Callus Development and Organogenesis in Cultured Explants of Cowpea (Vigna unguiculata (L.) Walp

Access: Use of this item is restricted to the UNT Community
Cowpea, Vigna unguiculata (L.) Walp is an excellent source of protein, vitamins and minerals and a major food crop many parts of Africa. Optimal production levels are hampered by insect pests and diseases. Biotechnological techniques such as tissue culture and genetic engineering can aid in the development of varieties with resistance to insect pests and diseases. The objective of this study was to investigate conditions necessary for the development of a reproducible tissue culture system that can be applied to regenerate transformed cells from culture. The in vitro manipulation of cowpea using Murashige and Skoog (MS) medium, auxins and cytokinins resulted in the formation of callus and rhizogenesis. Calli that were formed were separated into six classes based on color and texture. Yellowish friable callus, yellowish compact, soft yellowish callus and green and white were composed of largely vacuolated cells and were non-regenerative. Friable green callus was the most prevalent callus type and could form of roots in some hormone combinations. Green spots were formed on hard compact green callus. The green spots became nodular, forming root primordia and ultimately giving rise to roots. None of the six calli types gave rise to the formation of shoots. Embryogenic callus was …
Date: December 2004
Creator: Omwenga, George Isanda
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Camille Saint-Säens'  Piano Concerto No. 5 in F Major, Opus 103: An Analytical Study of Form, Compositional Techniques, and a Performance Perspective (open access)

Camille Saint-Säens' Piano Concerto No. 5 in F Major, Opus 103: An Analytical Study of Form, Compositional Techniques, and a Performance Perspective

The majority of books about Saint-Säens cover his life, compositions, contemporaries, and French music in general. Although his life is well documented, most sources present only brief analyses of his works; there is not one single comprehensive and exhaustive study of the Piano Concerto in F Major, Opus 103, available in the current literature. This study aims at filling the gap by providing other musicians interested in performing this piece with an initial study-guide. The research for this study focuses on several aspects of Saint-Säens' music. The currently available literature and past research is thoroughly examined, appraised, and quoted when relevant to the discussion. The original score of the concerto is analyzed regarding its form, compositional style, and performance indications. Diagrams, charts, and musical examples are presented to illustrate and substantiate the researcher's conclusions. Chapter I presents the topic and purpose of this study, a brief biography of Saint-Säens, a chronological overview of his five piano concertos, and the historical background of the Piano Concerto No. 5 in F Major, Opus 103. Chapter II presents a formal analysis and a compositional analysis of Opus 103. Chapter III presents a perspective of Saint-Säens playing style and performance recommendations by the author. …
Date: December 2004
Creator: Yoo, Seung Won
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Carbon Nanotube/Microwave Interactions and Applications to Hydrogen Fuel Cells.

Access: Use of this item is restricted to the UNT Community
One of the leading problems that will be carried into the 21st century is that of alternative fuels to get our planet away from the consumption of fossil fuels. There has been a growing interest in the use of nanotechnology to somehow aid in this progression. There are several unanswered questions in how to do this. It is known that carbon nanotubes will store hydrogen but it is unclear how to increase that storage capacity and how to remove this hydrogen fuel once stored. This document offers some answers to these questions. It is possible to implant more hydrogen in a nanotube sample using a technique of ion implantation at energy levels ~50keV and below. This, accompanied with the rapid removal of that stored hydrogen through the application of a microwave field, proves to be one promising avenue to solve these two unanswered questions.
Date: May 2004
Creator: Imholt, Timothy James
Object Type: Thesis or Dissertation
System: The UNT Digital Library

City of Denton Municipal Solid Waste Characterization and Management Strategies

Access: Use of this item is restricted to the UNT Community
Due to concern about diminishing landfill space, the City of Denton contracted a municipal solid waste characterization study in 1999 that would identify materials for diversion. This paper describes the results of 5 1-week waste sorting events, a scale-house analysis, a recycling participation study, a recycler profile and a similar city study. The results of the characterization studies suggest that at least 50% of each waste stream is recyclable or divertible though paper products accounted for no more than 45% by weight of any waste stream. Curbside recycling participation rate was 71% during the 6-week study period though the average weekly set-out rate was 37%. Recycling participation rates varied significantly by zip code and by home value categories but not by gender. Denton is fairly progressive in its waste management approach when compared to demographically similar cities on a 15-question assessment though recommendations for improvement have been identified.
Date: May 2004
Creator: Brady, Patricia D.
Object Type: Thesis or Dissertation
System: The UNT Digital Library