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Fluorination Effect on the Conformational Properties of Alkanes

Description: A Series of fluorophores of the general formular P(CF2)nP and P(CF2)n-1CF3 has been synthesized. Copper catalyzed coupling of 1-bromopyrene and the corresponding mono and di-iodoperfluoroalkanes were used in most cases. For the n=3 dimer, a novel 1,w-perfluoroalkylation of pyrene via bis-decarboxylation of hexafluorogultaric acid was utilized. These compounds, along with suitable hydrocarbon analogs, are being used to study the flexibility of fluorocarbon chains using emission. We have found that the excimer formation for the fluorinated pyrene monomers is highly dependent on concentration and is less efficient than for pyene. Excimer formation for the fluorinated pyrene dimers is much more efficient than for the fluorocarbon monomers and is only slightly concentraion dependent. Steady-state emission spectra indicate hydrocarbon dimers-models form excimers more efficiently than the fluorinated dimers suggesting the fluorinated chains are stiffer than the hydrocarbons. We conducted the temperature-dependent studies and quantified the conformational difference.
Date: May 2002
Creator: Xu, Wenjian
Partner: UNT Libraries

The Construct Validity of Self-Reported Historical Physical Activity

Description: The purpose of this study was to determine the construct validity of self-reported historical walking, running, and jogging (WRJ) activity. The criterion measure was concurrent performance on a maximal treadmill test. Subjects completed a medical exam and treadmill test between the years 1976 and 1985, and completed a follow-up questionnaire in 1986. Questionnaire included an item that assessed WRJ for each year from 1976 through 1985. Data analysis included Spearman correlations, partial correlations, ANOVA, and ANCOVA. Results indicated self-reported historical WRJ can be assessed with reasonable validity when compared with concurrently measured treadmill performance, and there is no decay in the accuracy of this reporting for up to ten years in the past.
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Date: May 2002
Creator: Bowles, Heather R.
Partner: UNT Libraries

Are the Needs of North Dakota's Aging Population with Developmental Disabilities Being Overlooked?

Description: North Dakota is faced with the challenge of meeting the needs of its growing population of elderly persons aging with a developmental disability. The challenge of creating new service models presents itself to professionals in the fields of Aging and Developmental Disabilities. Traditionally, the aging person with a developmental disability has been sent to nursing homes or grouped into community programs with younger persons with developmental disability. North Dakota is looking toward the future of caring for this special population through integration with elderly without disabilities.
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Date: May 2002
Creator: Clark, Amy Klein
Partner: UNT Libraries

Strategic Versus Sincere Behavior: The Impact of Issue Salience and Congress on the Supreme Court Docket

Description: The theory proposed here is that the Supreme Court behaves in a strategic manner at the agenda-setting stage in order to vote sincerely on the merits. To test this, I measure the impact issue salience and ideological distance between Congress and the Supreme Court has on the agenda. The results indicate that whether the Supreme Court behaves either sincerely or strategically depends on the policy area. The strategic nature of the Supreme Court at the agenda-setting phase may be in large part why some research shows that the Court behaves sincerely when voting on the merits. By behaving strategically at the agenda-setting phase, the Court is free to vote sincerely in later parts of the judicial process.
Date: May 2002
Creator: Williams, Jeffrey David
Partner: UNT Libraries

The Effects of Non-differential Reinforcement and Differential Reinforcement on Problem Behaviors and Accuracy of Responding of Autistic Children.

Description: The effects of non-differential reinforcement and differential reinforcement on problem behaviors and accuracy of responding of autistic children was examined. In experiment 1, one child with autism participated, and in experiment 2, two children with autism participated. In the non-differential reinforcement condition both prompted and unprompted responses were reinforced. In the differential reinforcement condition only unprompted responses were reinforced. Overall, problem behaviors were more frequent in the non-differential reinforcement condition. In experiment 1, accuracy was higher in the differential reinforcement condition, while experiment 2 showed inconclusive results with regards to accuracy. It is concluded that non-differential reinforcement can decrease problem behaviors in teaching situations, but may not be sufficient to ensure acquisition of target tasks.
Date: May 2002
Creator: Ingvarsson, Einar Thor
Partner: UNT Libraries

Competency to Stand Trial: A Systematic Evaluation and Validation of the GCCT, MacCAT-CA, and ECST as Competency Measures

Description: Competency to stand trial cases constitute the largest percentage of forensic referrals for clinical psychologists. Furthermore, research suggests that the use of forensic measures facilitates the decisions of competency made by forensic examiners. This study investigated the construct validity of three competency measures: (a) the GCCT-MSH, (b) the MacCAT-CA, and (c) the ECST with 100 adult males incarcerated at the Tarrant County Jail in Fort Worth, TX. Construct validity was investigated via the use of a multitrait-multimethod research design for the three-prong conceptualization of the Dusky standard. Results indicated that current competency measures do an adequate job of assessing for factual understanding, but lack construct validity for two prongs: rational understanding and the ability to consult with counsel. In addition, the atypical presentation scales of the both GCCT and the ECST performed well at screening individuals for feigning. Finally, prediction of competency from clinical variables was also investigated. Psychotic symptoms and overall impairment were the strongest predictors of incompetency.
Date: May 2002
Creator: Grandjean, Nicole Rae
Partner: UNT Libraries

Theoretical Study of Second Harmonic Generation of a Blue Laser at 486 nm Using a BBO Crystal in a Standing Wave Buildup Cavity

Description: For a spectroscopy purpose, we are interested in producing continuous wave (CW) UV laser light at 243 nm with at least 2 mW power. The theory of nonlinear optics suggests that we should be able to produce a desired 2.9 mW of 243 nm light by second harmonic generation (SHG) from a 50 mW blue laser at 486 nm using a BBO crystal in a build up cavity. The most important physical parameters are calculated. A 10 mm Brewster cut BBO crystal can provide phase matching conditions for coupling two ordinary photons at 486 nm and make a secondary beam at 243 nm. The single pass conversion efficiency is calculated not to be enough to generate 2.9 mW of SH light. My investigation shows that a standing wave build up cavity can provide a buildup factor of 94 and an overall conversion efficiency of 5.9% if one use an input coupler mirror with 1.1% transmission at 486 nm.
Date: May 2002
Creator: Khademian, Ali
Partner: UNT Libraries

Supply chain relationships in apparel retail product development.

Description: The purpose of this study was to investigate supply chain relationships within the apparel retail product development process under a single site case study setting. Relationship determinants (i.e. drivers, facilitators and barriers) that facilitated or impeded the degree of collaborative efforts between the retailer and the supply chain members were identified. As the retailer integrated its product development process with its suppliers, a triangular relationship was formed between the retailer, the overseas manufacturers, and the designated suppliers. The study found that the retailer sought operational efficiency in its business relationships with supply chain members, but continued to seek long-term commitment in these relationships to establish a virtual vertical company.
Date: May 2002
Creator: Lee, Daton
Partner: UNT Libraries

An Analysis of the Effectiveness of Computer Assisted Instruction in General Chemistry at an Urban University.

Description: The science-major General Chemistry sequence offered at the University of Houston has been investigated with respect to the effectiveness of recent incorporation of various levels of computer technology. As part of this investigation, questionnaire responses, student evaluations and grade averages and distributions from up to the last ten years have been analyzed and compared. Increased use of web-based material is both popular and effective, particularly with respect to providing extra information and supplemental questions. Instructor contact via e-mail is also well-received. Both uses of technology should be encouraged. In contrast, electronic classroom presentation is less popular. While initial use may lead to improved grades and retention, these levels decrease quickly, possibly due to a reduction in instructor spontaneity.
Date: May 2002
Creator: McGuffey, Angela
Partner: UNT Libraries

A Behavioral Economic Analysis of the Effects of Unit Price Sequence on Demand for Money in Humans.

Description: Three groups of participants were exposed to different unit price sequences. Unit prices for all groups ranged from unit price 1 to 21. Analyses of demand curves, response rates, session duration, and elasticity coefficients suggest that the sequence of exposure to unit prices can affect the elasticity of demand. In addition, the size of unit price contrast, direction of unit price change, and proximity to experimental milestones also may affect the consumption of monetary reinforcers.
Date: May 2002
Creator: Williams, Jack Keith
Partner: UNT Libraries

Effects of Sublethal Copper Exposure on Escape Behavior and Growth of Rana pipiens Tadpoles

Description: This research is designed to test how sublethal exposure to copper affects tadpole predator-escape behavior and how quickly tadpoles recover. After exposure, tadpoles were separated. Escape behavior was recorded for two-thirds of exposed tadpoles while one-third of the exposed population was measured weekly to determine growth and recovery. Control tadpoles were consumed within 15 minutes whereas those exposed to higher concentrations were consumed at a slower rate, which does not support the hypotheses. Although the rate of predation was lower, tadpoles exposed to higher Cu concentrations were on average, 1.47 cm in total body length. Those exposed to 0.93 mg/L averaged 0.86 cm. After being placed into clean water, treatment tadpoles recovered after 20 days.
Date: May 2002
Creator: Redick, Melinda
Partner: UNT Libraries

Distant Proximity: Mapping Presence and Absence

Description: Chapter I presents my background as an artist born and raised in Romania, and describes my artwork in connection with my interests and experiences. Maps and traditional Romanian art are important sources of influence. The questions in the statement of problem deal with the way ideas, references to various elements, and installation impact the artwork. Chapter II discusses the installation at the Dallas Visual Art Center, the creative process, and how the artwork addressed the questions in the statement of problem. Important points are: a step into three-dimensionality with the tall, freestanding pieces painted on both sides, the use of topographical contours in creating shapes, issues of form and content as expressed in the painted surfaces, and the interaction of the individual works in the installation.
Date: May 2002
Creator: Mitroi, Tudor
Partner: UNT Libraries

A study of stock price reactions to the decisions of the Federal Open Market Committee (FOMC) on changes in the federal funds rate.

Description: This paper analyzes stock index reactions to interest rate actions by the FOMC. Unlike previous analyses this study utilizes macro-economic indicators and accounts for pre-decision market expectations. Results indicate significant reaction of the stock market to the actions of the FOMC regardless of interest rate actions matching pre-decision market expectations. Binary dummy variables representing the five days following an FOMC meeting indicate a significant reaction for days one; two and three of the Dow Jones model and for day five of the NASDAQ model. The magnitude of the coefficients are 0.17%, 0.09%, -0.07% and -.15% respectively. These findings may be sensitive to a priori choices regarding the definition of the market expectation variable.
Date: May 2002
Creator: Bushnell, Wesley
Partner: UNT Libraries

Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms

Description: In this study we applied ultra-short laser pulses on a biological sample (Arabidopsis), in order to cut it precisely in a square pattern and subsequently use it for studying stress generation mechanisms. For this purpose, we utilized femtosecond laser pulses at 100 fs pulse width and 80 MHz repetition rate. We took two processing parameters into consideration such as laser power, laser exposure time which is related to the stage speed. Therefore, we were able to find the laser optimum conditions for ablation of biological tissues. The mutant and wildtype (control) obtained from laser cutting with a size of 500 µm × 500 µm were directly transferred (in-situ with laser cutting) into a microfabricated chamber containing ~500 nanoliters deionized water for measuring ion conductivity. The ion conductivity is a signature of cell-death mechanisms caused by various stresses. A light with intensity of 100 µmol was exposed to the samples for 2 hours and 20 minutes as a source of stress. A quantitative electrical analysis with high accuracy was assured by utilizing a microchamber, which enables a measurement in nanoliter volume. We measured the impedance which is reciprocal of conductivity using a lock-in amplifier and a precise current source at frequency of 130 Hz. Initially high impedance of mutant sample tended to drop within 2 hours and finally approached the constant value which signified that the cell death mechanism was complete. However, the wildtype sample demonstrated approximately constant impedance (conductivity) during the experiment.
Date: August 2010
Creator: Abtahi, Seyed Ali
Partner: UNT Libraries

Hepatotoxicity of Mercury to Fish

Description: Tissue samples from spotted gar (Lepisosteus oculatus) and largemouth bass (Micropterus salmoides) were collected from Caddo Lake. Gar and bass livers were subjected to histological investigation and color analysis. Liver color (as abs at 400 nm) was significantly correlated with total mercury in the liver (r2 = 0.57, p = 0.02) and muscle (r2 = 0.58, p = 0.01) of gar. Evidence of liver damage as lipofuscin and discoloration was found in both species but only correlated with liver mercury concentration in spotted gar. Inorganic mercury was the predominant form in gar livers. In order to determine the role of mercury speciation in fish liver damage, a laboratory feeding study was employed. Zebrafish (Danio rerio) were fed either a control (0.12 ± 0.002 µg Hg.g-1 dry wt), inorganic mercury (5.03 ± 0.309 µg Hg.g-1 dry wt), or methylmercury (4.11 ± 0.146 µg Hg.g-1 dry wt) diet. After 78 days of feeding, total mercury was highest in the carcass of zebrafish fed methylmercury (12.49 ± 0.369 µg Hg.g-1 dry wt), intermediate in those fed inorganic mercury (1.09 ± 0.117 µg Hg.g-1 dry wt), and lowest in fish fed the control diet (0.48 ± 0.038 µg Hg.g-1 dry wt). Total mercury was highest in the viscera of methylmercury fed zebrafish (11.6 ± 1.86 µg Hg.g-1 dry wt), intermediate in those fed inorganic diets (4.3 ± 1.08 µg Hg.g-1 dry wt), and lowest in the control fish (below limit of detection). Total mercury was negatively associated with fish length and weight in methylmercury fed fish. Condition factor was not associated with total mercury and might not be the best measure of fitness for these fish. No liver pathologies were observed in zebrafish from any treatment.
Date: August 2010
Creator: Barst, Benjamin Daniel
Partner: UNT Libraries

Interactions of N-Acylethanolamine Metabolism and Abscisic Acid Signaling in Arabidopsis Thaliana Seedlings

Description: N-Acylethanolamines (NAEs) are endogenous plant lipids hydrolyzed by fatty acid amide hydrolase (FAAH). When wildtype Arabidopsis thaliana seeds were germinated and grown in exogenous NAE 12:0 (35 µM and above), growth was severely reduced in a concentration dependent manner. Wildtype A. thaliana seeds sown on exogenous abscisic acid (ABA) exhibited similar growth reduction to that seen with NAE treatment. AtFAAH knockouts grew and developed similarly to WT, but AtFAAH overexpressor lines show markedly enhanced sensitivity to ABA. When low levels of NAE and ABA, which have very little effect on growth alone, were combined, there was a dramatic reduction in seedling growth in all three genotypes, indicating a synergistic interaction between ABA and NAE. Notably, this synergistic arrest of seedling growth was partially reversed in the ABA insensitive (abi) mutant abi3-1, indicating that a functional ABA signaling pathway is required for the full synergistic effect. This synergistic growth arrest results in an increased accumulation of NAEs, but no concomitant increase in ABA levels. The combined NAE and ABA treatment induced a dose-dependent increase in ABI3 transcript levels, which was inversely related to growth. The ABA responsive genes AtHVA22B and RD29B also had increased expression in both NAE and ABA treatment. The abi3-1 mutant showed no expression of ABI3 and AtHVA22B, but RD29B expression remained similar to wildtype seedlings, suggesting an alternate mechanism for NAE and ABA interaction. Taken together, these data suggest that NAE metabolism acts through ABI3-dependent and independent pathways in the negative regulation of seedling development.
Date: August 2010
Creator: Cotter, Matthew Q.
Partner: UNT Libraries

Determination of the Shelf Life of Aluminum Electrolytic Capacitors.

Description: The aluminum electrolytic capacitor is used extensively in the electric utility industry. A factor limiting the storage of spare capacitors is the integrity of the aluminum oxide dielectric, which over time breaks down contributing to a shelf life currently estimated at one nuclear power electric generating station to be approximately five years. This project examined the electrical characteristics of naturally aged capacitors of several different styles to determine if design parameters were still within limits. Additionally, the effectiveness of a technique known as “Reforming” was examined to determine its impact on those characteristics.
Date: May 2002
Creator: Wynne, Edward McFaddin
Partner: UNT Libraries

Surfacing the Void

Description: Surfacing the Void is an exploration of surface design in relationship to the topic of voids. For the purpose of this paper, two types of void were addressed: shelters and hulls. The theme behind the sculptural works dealt with negative spaces as an analogy for the voids in people's lives. The goal was to find a way for the surfaces to elicit an emotional response from the viewer that correlates to the impression of either shelter or hull. Keeping this in mind, each experiment was approached with how to best represent the meaning of void being manifested. Imagery was applied during different states of the clay: wet, dry, and fired. Methods of exploration included texturing, drawing, stenciling, stamping, incising, decoupage and covering the surfaces with textiles.
Date: May 2002
Creator: Williamson, Melanie L.
Partner: UNT Libraries

How to Factor Loss

Description: How to Factor Loss is a collection of poems and translations prefaced by a critical paper over Robert Hass's “Meditation at Lagunitas.” The preface, “A Sensuous Theory, A Sensuous Poem,” explores how Hass merges the discourses of theory and poetry to create a poem that hangs suspended between a confidence and an anxiety about language. The poems in this thesis are primarily responses to finitude. The first section turns toward an “other” as a strategy of placating desire and of reaching both inward and outward. The second section explores the potential failures of art as a means of touching objects. The final section acknowledges that finitude is the condition of humankind, and it turns toward a more tender language, one that embraces limitations and is filled with something like faith. The collection is followed by an appendix which contains translations of several poems by René Guy Cadou and Georg Trakl.
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Date: May 2002
Creator: Hall, Todd R.
Partner: UNT Libraries

Blackland Prairie

Description: Blackland Prairie contains a scholarly preface, “Cross Timbers,” that discusses the emerging role of place as a narrative agent in contemporary fiction. The preface is followed by six original short stories. “Parts” depicts the growth of a boy's power over his family. “A Movie House to Make Us All Rich” involves the sacrifice of familial values by the son of Italian immigrants in the early 20th century. “The Place on Chenango Street” is about a man who views his world in monetary terms. “The Nine Ideas For A Happier Whole” explores the self-help industry and personal guru age. “All The Stupid Things I Said” is about a long-separated couple meeting for very different reasons. “Flooded Timber” concerns a couple who discover hidden reasons for their relationship's longevity.
Date: May 2002
Creator: Magliocco, Amos
Partner: UNT Libraries

Eye of the beholder: Children respond to beauty in art.

Description: The purpose of this study was to determine if beauty was important to elementary age children when exploring and making aesthetic judgements about works of art and to determine the criteria elementary students used in judging beauty in works of art. This study also explored beauty as a concept that could be used as an organizing idea for designing a thematic unit with the purpose of introducing elementary students to postmodern art and issues. One hundred and sixty first grade and fourth grade students looked at 20 pairs of art reproductions and picked the artwork they considered the most beautiful. The criteria elementary students use for determining beauty in artworks was found to be color, realism, subject matter and physical appearance of the subject of the work of art.
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Date: May 2002
Creator: Meli, Alisa A.
Partner: UNT Libraries

Viewers' Choice

Description: This paper documents the execution and exhibition of a group of oil paintings exploring themes of spectacle and the construction of reality in contemporary American society. The paintings are composed of figures and fragments of text originating in stills taken from television news and reality TV. This paper describes and assesses the paintings according to a set of questions developed by the artist at the inception of the project. Various strategies employed in the execution of the work are analyzed and compared. The contribution of this project to the field of contemporary visual art is evaluated via comparison with other art, past and present, expressing similar concerns.
Date: May 2002
Creator: Brownlee, Tracie
Partner: UNT Libraries

Implementation of Scalable Secure Multicasting

Description: A large number of applications like multi-player games, video conferencing, chat groups and network management are presently based on multicast communication. As the group communication model is being deployed for mainstream use, it is critical to provide security mechanisms that facilitate confidentiality, authenticity and integrity in group communications. Providing security in multicast communication requires addressing the problem of scalability in group key distribution. Scalability is a concern in group communication due to group membership dynamics. Joining and leaving of members requires the distribution of a new session key to all the existing members of the group. The two approaches to key management namely centralized and distributed approaches are reviewed. A hybrid solution is then provided, which represents a improved scalable and robust approach for a secure multicast framework. This framework then is implemented in an example application of a multicast news service.
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Date: August 2002
Creator: Vellanki, Ramakrishnaprasad
Partner: UNT Libraries

Tiger; a stage play, and a reflective essay detailing the writing process

Description: This thesis includes a full length play and a separate section describing the creation of this play. The play depicts family members struggling with the direct and indirect ramifications of alcoholism, depression, and suicide. The play is composed of two acts; act one contains eight scenes, and act two contains six scenes. It is set in the 1950s and 1960s and takes place in various areas of the family home, at a wedding reception, and at a funeral. The essay section includes a description of the process, a record of changes in the play's direction, notations of personal discoveries, and a self evaluation of the strengths and weaknesses of the play.
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Date: August 2002
Creator: Westkaemper, Lisa
Partner: UNT Libraries