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Latent Transition Analysis of Pre-service Teachers' Efficacy in Mathematics and Science (open access)

Latent Transition Analysis of Pre-service Teachers' Efficacy in Mathematics and Science

This study modeled changes in pre-service teacher efficacy in mathematics and science over the course of the final year of teacher preparation using latent transition analysis (LTA), a longitudinal form of analysis that builds on two modeling traditions (latent class analysis (LCA) and auto-regressive modeling). Data were collected using the STEBI-B, MTEBI-r, and the ABNTMS instruments. The findings suggest that LTA is a viable technique for use in teacher efficacy research. Teacher efficacy is modeled as a construct with two dimensions: personal teaching efficacy (PTE) and outcome expectancy (OE). Findings suggest that the mathematics and science teaching efficacy (PTE) of pre-service teachers is a multi-class phenomena. The analyses revealed a four-class model of PTE at the beginning and end of the final year of teacher training. Results indicate that when pre-service teachers transition between classes, they tend to move from a lower efficacy class into a higher efficacy class. In addition, the findings suggest that time-varying variables (attitudes and beliefs) and time-invariant variables (previous coursework, previous experiences, and teacher perceptions) are statistically significant predictors of efficacy class membership. Further, analyses suggest that the measures used to assess outcome expectancy are not suitable for LCA and LTA procedures.
Date: December 2009
Creator: Ward, Elizabeth Kennedy
System: The UNT Digital Library
Level Curves of the Angle Function of a Positive Definite Symmetric Matrix (open access)

Level Curves of the Angle Function of a Positive Definite Symmetric Matrix

Given a real N by N matrix A, write p(A) for the maximum angle by which A rotates any unit vector. Suppose that A and B are positive definite symmetric (PDS) N by N matrices. Then their Jordan product {A, B} := AB + BA is also symmetric, but not necessarily positive definite. If p(A) + p(B) is obtuse, then there exists a special orthogonal matrix S such that {A, SBS^(-1)} is indefinite. Of course, if A and B commute, then {A, B} is positive definite. Our work grows from the following question: if A and B are commuting positive definite symmetric matrices such that p(A) + p(B) is obtuse, what is the minimal p(S) such that {A, SBS^(-1)} indefinite? In this dissertation we will describe the level curves of the angle function mapping a unit vector x to the angle between x and Ax for a 3 by 3 PDS matrix A, and discuss their interaction with those of a second such matrix.
Date: December 2009
Creator: Bajracharya, Neeraj
System: The UNT Digital Library
An Evaluation of the Effects of Two Different Role Play Formats on the Outcomes of a Parent Training Curriculum (open access)

An Evaluation of the Effects of Two Different Role Play Formats on the Outcomes of a Parent Training Curriculum

The current study was designed to replicate and extend previous research on the effectiveness of behavioral parent training. Specifically, the effectiveness of the Behavior Management and Parenting Services (BMAPS) curriculum in teaching parents to exhibit a set of parenting skills and respond accurately to a multiple choice examination about positive parenting techniques was evaluated. In addition, the curriculum was revised so that the relative effectiveness and acceptability of two role play formats could be assessed. The outcomes of the study showed an improvement in the participants' ability to identify correct answers on a multiple choice examination and apply the parenting skills taught in class within a role play format; results pertaining to the efficacy of each role play format were less conclusive.
Date: December 2009
Creator: Carlson Litscher, Barbara J.
System: The UNT Digital Library
A New Wireless Sensor Node Design for Program Isolation and Power Flexibility (open access)

A New Wireless Sensor Node Design for Program Isolation and Power Flexibility

Over-the-air programming systems for wireless sensor networks have drawbacks that stem from fundamental limitations in the hardware used in current sensor nodes. Also, advances in technology make it feasible to use capacitors as the sole energy storage mechanism for sensor nodes using energy harvesting, but most current designs require additional electronics. These two considerations led to the design of a new sensor node. A microcontroller was chosen that meets the Popek and Goldberg virtualization requirements. The hardware design for this new sensor node is presented, as well as a preliminary operating system. The prototypes are tested, and demonstrated to be sustainable with a capacitor and solar panel. The issue of capacitor leakage is considered and measured.
Date: December 2009
Creator: Skelton, Adam W.
System: The UNT Digital Library
Racial Stereotypes and Racial Assimilation in a Multiracial Society (open access)

Racial Stereotypes and Racial Assimilation in a Multiracial Society

Interest in a multiracial society has increased in recent years and including on racism and prejudice and in the propensity to stereotype out-groups. Theories on racism help explain the dominant group's prejudice toward subordinate groups. Yet they only explain why dominant group members stereotype subordinates or if the dominant group's propensity to stereotype is different from that of subordinate groups. Recent assimilation theories suggest that some minorities are assimilating with Whites but Blacks are not undergoing assimilation. Classic assimilation theory suggests that when a subordinate group assimilates with the dominant group then they will also take on the dominant group's values and beliefs, including their prejudices and propensities to stereotype. The use of racial stereotypes in support of the assimilation of a minority group has not been tested. Results from the LSAF national survey provide support for Asians to be assimilating with Whites. However, Hispanics do not appear to be taking on Whites' propensity to stereotype, contradicting the prediction that Hispanics are assimilating with Whites.
Date: December 2009
Creator: Youngblood, Thomas
System: The UNT Digital Library
Survey of Approximation Algorithms for Set Cover Problem (open access)

Survey of Approximation Algorithms for Set Cover Problem

In this thesis, I survey 11 approximation algorithms for unweighted set cover problem. I have also implemented the three algorithms and created a software library that stores the code I have written. The algorithms I survey are: 1. Johnson's standard greedy; 2. f-frequency greedy; 3. Goldsmidt, Hochbaum and Yu's modified greedy; 4. Halldorsson's local optimization; 5. Dur and Furer semi local optimization; 6. Asaf Levin's improvement to Dur and Furer; 7. Simple rounding; 8. Randomized rounding; 9. LP duality; 10. Primal-dual schema; and 11. Network flow technique. Most of the algorithms surveyed are refinements of standard greedy algorithm.
Date: December 2009
Creator: Dutta, Himanshu Shekhar
System: The UNT Digital Library
An Evaluation Model for Identifying Lewisville and San Angelo, Texas, as Senior Ready Communities (open access)

An Evaluation Model for Identifying Lewisville and San Angelo, Texas, as Senior Ready Communities

This research portrays a paradigm for the assessment of aging services to support populations aging in place. The dissertation was designed to establish a model to identify and evaluate senior ready communities. Area specific social programs and services are identified. In order to meet the growing needs of aging populations, the dynamic representation of existing services and the need for services that could be developed in certain communities require reevaluation in current planning, restructuring, and/or community development.
Date: December 2009
Creator: Sanders, David N.
System: The UNT Digital Library
An Investigation Into the Factors Leading to the Closure of 40 Private Four-Year Colleges between 1965 and 2005 (open access)

An Investigation Into the Factors Leading to the Closure of 40 Private Four-Year Colleges between 1965 and 2005

This study searches for a set of common indicators that contributed to the ultimate closure of 40 colleges and universities between 1965 and 2005. From research on related literature, a set of 31 contributing factors was identified by published experts and observers in higher education. That set of indicators was then used as a list of 31 questions answered by data found in newspaper articles, professional journals, published research work, published institutional records, data taken from the Department of Education, data taken from IPEDS, data published in historical recounts of the colleges of interest, etc. The data was accumulated in the form of yes/no responses to the 31 questions. Although the study involved only 40 colleges and universities this population represents the majority of institutions that pass the restrictions of limitations and delimitations described in the full document. The complete data set was processed using SPSS which produced ANOVA tables and level of statistical significance for each indicator question. The results indicate that out of the 31 original indicator questions there were two groups of statistically significant indicators. The larger group of indicators having statistical significance at the .05 level encompassed the smaller group having statistical significance at the .001 …
Date: December 2009
Creator: Province, Terry Paul
System: The UNT Digital Library
Health Status and Access Disparities Among the Uninsured Working-Age Population in a Safety-Net Healthcare Network in Tarrant County, Texas (open access)

Health Status and Access Disparities Among the Uninsured Working-Age Population in a Safety-Net Healthcare Network in Tarrant County, Texas

The objective of this research was to determine if healthcare access disparities exist across race and gender in a publically funded safety-net healthcare system in Texas. Data were examined from a representative random sample of 1468 adults aged 18-64 who were patients in this safety-net system in July and August of 2000 and were analyzed using binary logistic regression and chi-square measures of significance. Major Findings: On measures of health status - overall health rating (p =.051), limited employment (p =.000), energy level (p =.001), and worry (p =.012) - Anglos reported the worst health; Mexican Americans, the best health; with African Americans intermediate. Mexican Americans were more likely to have never had health insurance, and to also have had insurance in the past year; Anglos were least likely to have ever had insurance (p =.015) or to have had insurance in the past year (p =.000). On use of EDs (p =.028), problems getting prescription medicines (p =.029), and foregoing other necessities of life to pay for healthcare, Mexican Americans were least disadvantaged with African Americans reporting greatest use of EDs among both men and women, and Anglos the most problems with prescription medicines and foregoing care, especially among …
Date: December 2009
Creator: Queen, Courtney M.
System: The UNT Digital Library
High Resolution Satellite Images and LiDAR Data for Small-Area Building Extraction and Population Estimation (open access)

High Resolution Satellite Images and LiDAR Data for Small-Area Building Extraction and Population Estimation

Population estimation in inter-censual years has many important applications. In this research, high-resolution pan-sharpened IKONOS image, LiDAR data, and parcel data are used to estimate small-area population in the eastern part of the city of Denton, Texas. Residential buildings are extracted through object-based classification techniques supported by shape indices and spectral signatures. Three population indicators -building count, building volume and building area at block level are derived using spatial joining and zonal statistics in GIS. Linear regression and geographically weighted regression (GWR) models generated using the three variables and the census data are used to estimate population at the census block level. The maximum total estimation accuracy that can be attained by the models is 94.21%. Accuracy assessments suggest that the GWR models outperformed linear regression models due to their better handling of spatial heterogeneity. Models generated from building volume and area gave better results. The models have lower accuracy in both densely populated census blocks and sparsely populated census blocks, which could be partly attributed to the lower accuracy of the LiDAR data used.
Date: December 2009
Creator: Ramesh, Sathya
System: The UNT Digital Library
The Effects of Attendance at a Senior Center on the Quality of Life and Well Being of Grandparents Rearing Grandchildren. (open access)

The Effects of Attendance at a Senior Center on the Quality of Life and Well Being of Grandparents Rearing Grandchildren.

The purpose of this study was to determine the effects of attendance at a senior center on the well being and quality of life of grandparents that were rearing grandchildren. Using convenience sampling, grandparents (N=130) who were rearing grandchildren were given a self administered demographic data survey along with an attendance at a senior center questionnaire, the Quality of Life Scale, the Well Being Scale by Liang, the UCLA Loneliness Scale, the Caregiver Burden Scale, and the Role Satisfaction Scale. An initial MANOVA (F 7, 69 = 2.72, p < .01) suggesting that senior center attendance affect the measures as a set was conducted and then a series of one way ANOVAs were carried out to test the hypothesis that attending a senior center has an effect on the dependent variables: well being, quality of life, role satisfaction, caregiver burden, loneliness, current health, and heath one year ago. Subsequently, a hierarchical regression analysis was conducted to find out whether frequency and quality of attendance of a senior center predicted quality of life, caregiver burden, well being, loneliness, and role satisfaction, controlling for the demographic data. The results of the MANOVA showed that the dependent variables: quality of life, caregiver burden, …
Date: December 2009
Creator: Rhynes, LaTrica Q.
System: The UNT Digital Library
Victimization and expressions of relational and overt aggression among boys and girls with ADHD. (open access)

Victimization and expressions of relational and overt aggression among boys and girls with ADHD.

This study investigated if girls and boys high in ADHD symptomology exhibited and experienced relational and overt aggression differently than boys and girls without ADHD symptoms using peer, parent and teacher ratings. A measurement of social behavior for parent ratings was also validated. Using archival data, 371 3rd- 6th graders from a north Texas school district participated in the study, along with a parent or guardian and teachers. Results supported that ADHD subtype predicted more overt aggression according to parents and teachers but not peers. ADHD subtype did not predict more relational aggression but ADHD symptomology did. Contrary to past research, gender did not moderate relational aggression or internalizing symptoms from relational victimization. Furthermore, a parent version of the Child Social Behavior Scale was found to effectively measure relational, overt and prosocial behavior. Limitations, future directions and implications are discussed.
Date: December 2009
Creator: Rivero, Arlene Jean Abello
System: The UNT Digital Library
Inferring Social and Internal Context Using a Mobile Phone (open access)

Inferring Social and Internal Context Using a Mobile Phone

This dissertation is composed of research studies that contribute to three research areas including social context-aware computing, internal context-aware computing, and human behavioral data mining. In social context-aware computing, four studies are conducted. First, mobile phone user calling behavioral patterns are characterized in forms of randomness level where relationships among them are then identified. Next, a study is conducted to investigate the relationship between the calling behavior and organizational groups. Third, a method is presented to quantitatively define mobile social closeness and social groups, which are then used to identify social group sizes and scaling ratio. Last, based on the mobile social grouping framework, the significant role of social ties in communication patterns is revealed. In internal context-aware computing, two studies are conducted where the notions of internal context are intention and situation. For intentional context, the goal is to sense the intention of the user in placing calls. A model is thus presented for predicting future calls envisaged as a call predicted list (CPL), which makes use of call history to build a probabilistic model of calling behavior. As an incoming call predictor, CPL is a list of numbers/contacts that are the most likely to be the callers within …
Date: December 2009
Creator: Phithakkitnukoon, Santi
System: The UNT Digital Library
Design and Validation of an Automated Multiunit Composting System. (open access)

Design and Validation of an Automated Multiunit Composting System.

This thesis covers the design of an automated multiunit composting system (AMUCS) that was constructed to meet the experimental apparatus requirements of the ASTM D5338 standard. The design of the AMUCS is discussed in full detail and validated with two experiments. The first experiment was used to validate the operation of the AMUCS with a 15 day experiment. During this experiment visual observations were made to visually observe degradation. Thermal properties and stability tests were performed to quantify the effects of degradation on the polymer samples, and the carbon metabolized from the degradation of samples was measured. The second experiment used the AMUCS to determine the effect of synthetic clay nanofiller on the aerobic biodegradability behavior of poly (3-hydroxybutyrate-co-3-hydroxyvalerate).
Date: December 2009
Creator: Pickens, Mark Everett
System: The UNT Digital Library
Does the Knowledge of Unaudited Account Balances Adversely Affect the Performance of Substantive Analytical Procedures? (open access)

Does the Knowledge of Unaudited Account Balances Adversely Affect the Performance of Substantive Analytical Procedures?

Auditors use substantive analytical procedures to make assertions about the adequacy and appropriateness of client balances. The analytical procedure process consists of auditors creating independent account expectations and corroborating unusual fluctuations through obtaining and evaluating additional audit evidence. Prior analytical procedure research has found that knowledge of clients' unaudited account balances biases auditors' expectations towards the current year figures. However, this research has failed to examine the impact of biased expectations on the subsequent stages of analytical procedures. This dissertation assesses the full impact of biased account expectations on auditors' use of analytical procedures. I experimentally test the hypotheses of my dissertation through administering an experiment to senior level auditors. After inducing an account expectation bias that favors the client account balance in half the participants, I examine the auditors' cognitive investigation into an unusual account fluctuation. The results indicate that a biased account expectation negatively affects auditors' judgment quality. In particular, a biased expectation leads auditors to favor hypotheses and additional information that supports the proposition that the client's balance is reasonably stated. Alternatively, auditors with unbiased account expectations are more willing to consider all hypotheses and are able to identify the most pertinent additional information to the decision …
Date: December 2009
Creator: Pike, Byron J.
System: The UNT Digital Library
The perception of English language arts teachers about instructional changes following the implementation of the Texas Assessment of Knowledge and Skills test. (open access)

The perception of English language arts teachers about instructional changes following the implementation of the Texas Assessment of Knowledge and Skills test.

Accountability in education has been expanding for the past twenty years. As standards for curricular areas continued to develop, educational shareholders desired a way to measure student achievement contextualized by the established standards. Since 1964, policies expanded federal involvement with education, and with the No Child Left Behind Act in 2001, high-stakes testing became a significant part of public education. In Texas, testing transitioned in 2003 to the Texas Assessment of Knowledge and Skill (TAKS) test, an assessment that determines grade advancement for students, ratings for school districts, and additional compensation for some teachers. Along with the increasing expectations for student achievement, the need for effective instruction also increases. This dissertation studies how English language arts (ELA) teachers in four North Texas suburban high schools perceive instructional change following the implementation of TAKS. One hundred twenty-one teachers (n=121) were surveyed using an instrument broken into seven categories: student-centered instruction, student interest, instructional communication, time, classroom environment, teacher knowledge, and assessment. Participants were separated into two groups, teachers with one to six years of experience with a district or seven or more years with a district. Using a rating scale for each statement on the survey instrument, participants indicated the direction …
Date: December 2009
Creator: Horn, Brian K.
System: The UNT Digital Library
Synthesis and Characterization of Platinum(II)(2-(9-anthracenylylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione)(dichloride), Platinum(II)(2-(9-anthracenylylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione(maleonitriledithiolate), and Platinum(II)(4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione)(4-Methyl-1,2-benzene dithiol) (open access)

Synthesis and Characterization of Platinum(II)(2-(9-anthracenylylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione)(dichloride), Platinum(II)(2-(9-anthracenylylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione(maleonitriledithiolate), and Platinum(II)(4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione)(4-Methyl-1,2-benzene dithiol)

Substitution of the 1,5-cyclooctadiene (cod) ligand in PtCl2(cod) (1) by the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) yields PtCl2(bpcd) (2). Knoevenagel condensation of 2 with 9-anthracenecarboxaldehyde leads to the functionalization of the bpcd ligand and formation of the corresponding 2-(9-anthracenylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (abpcd) substituted compound PtCl2(abpcd) (3), which is also obtained from the direct reaction of 1 with the abpcd ligand in near quantitative yield. The reaction of 3 with disodium maleonitriledithiolate (Na2mnt) affords the chelating dithiolate compound Pt(mnt)(abpcd) (4). The reaction of PtCl2(bpcd) (2) with 4-methyl-1,2-benzene dithiol under basic conditions affords Pt(tdt)(bpcd) (5). Compounds 2-5 have been fully characterized in solution by IR and NMR spectroscopies (1H and 31P), and their molecular structures established by X-ray crystallography. The electrochemical properties of 2&#8209;5 have examined by cyclic voltammetry, and the nature of the HOMO and LUMO levels in systems 2-4 has been established by MO calculations at the extended Hückel level, the results of which are discussed with respect to electrochemical data and related diphosphine derivatives. In addition the new compounds 2-5 have been isolated by column chromatography and characterized by IR, UV-Vis spectroscopy.
Date: December 2009
Creator: Hunt, Sean W.
System: The UNT Digital Library
The relationship of student characteristics, help seeking behavior, academic and environmental variables with student course completion in community college online courses: An application of a conceptual model. (open access)

The relationship of student characteristics, help seeking behavior, academic and environmental variables with student course completion in community college online courses: An application of a conceptual model.

The purpose of this study was to examine differences and relationships in student definition and background characteristics, help seeking behaviors, academic and environmental variables between and among community college students at a single institution who successfully completed and those who did not complete online courses during a single term. An adapted version of Bean and Metzner's conceptual model of nontraditional student attrition provided the theoretical framework for the study. The results of data analysis revealed statistically significant differences between completers and noncompleters on the basis of definition, gender, ethnicity, experience and prior GPA. Statistically significant relationships were found between definition, ethnicity, gender, experience, prior GPA, orientation and completion and noncompletion. No statistically significant interactions were found between definition and experience and help seeking behaviors. No statistically significant differences, relationships or predictor variables were found by degree seeking, preassessment, or technical help seeking. Additional analyses by defining characteristics revealed statistically significant differences between completers and noncompleters on the basis of residency, age and enrollment status. Predictor variables found to be significant were definition, gender, experience, prior GPA and orientation. The odds of completion increased with nontraditional definition, female gender, higher prior GPA, and orientation participation. The odds of completion decreased with …
Date: December 2009
Creator: Schumann, Sherry Haskin
System: The UNT Digital Library
Phosphorescent Emissions of Coinage Metal-Phosphine Complexes: Theory and Photophysics (open access)

Phosphorescent Emissions of Coinage Metal-Phosphine Complexes: Theory and Photophysics

The major topics discussed are all relevant to the bright phosphorescent emissions of coinage metal complexes (Cu(I), Ag(I) and Au(I)) with an explanation of the theoretical background, computational results and ongoing work on the application in materials and optoelectronic devices. Density functional computations have been performed on the majority of the discussed complexes and determined that the most significant distortion that occurs in Au(I)-phosphine complexes is a near and beyond a T-shape within the P-Au-P angle when the complexes are photoexcited to the lowest phosphorescent excited state. The large distortion is experimentally qualified with the large Stokes' shift that occurs between the excitation and emission spectra and can be as large as 18 000 cm-1 for the neutral Au(I) complexes. The excited state distortion has been thoroughly investigated and it is determined that not only is it pertinent to the efficient luminescence but also for the tunability in the emission. The factors that affect tunability have been determined to be electronics, sterics, rigidity of solution and temperature. The luminescent shifts determined from varying these parameters have been described systematically and have revealed emission colors that span the entire visible spectrum. These astounding features that have been discovered within studies of …
Date: December 2009
Creator: Sinha, Pankaj
System: The UNT Digital Library
E‐Shape Analysis (open access)

E‐Shape Analysis

The motivation of this work is to understand E-shape analysis and how it can be applied to various classification tasks. It has a powerful feature to not only look at what information is contained, but rather how that information looks. This new technique gives E-shape analysis the ability to be language independent and to some extent size independent. In this thesis, I present a new mechanism to characterize an email without using content or context called E-shape analysis for email. I explore the applications of the email shape by carrying out a case study; botnet detection and two possible applications: spam filtering and social-context based finger printing. The second part of this thesis takes what I apply E-shape analysis to activity recognition of humans. Using the Android platform and a T-Mobile G1 phone I collect data from the triaxial accelerometer and use it to classify the motion behavior of a subject.
Date: December 2009
Creator: Sroufe, Paul
System: The UNT Digital Library
Bidirectional Effects Between Engaged Lifestyle and Cognition in Later Life: Exploring the Moderation Hypothesis for Personality Variables. (open access)

Bidirectional Effects Between Engaged Lifestyle and Cognition in Later Life: Exploring the Moderation Hypothesis for Personality Variables.

Longitudinal data (N = 263) was used to investigate the bidirectional relationship between engagement (engaged lifestyle activities) and cognition (crystallized & fluid intelligence). Extroversion and openness to experience were also tested as moderators of the relationship between engagement and cognition. Results showed that the relationship between engagement at Wave 1 and cognition at Wave 2 did not differ from the relationship between cognition at Wave 1 and engagement at Wave 2. Testing for moderation with regression indicated that neither extroversion nor openness was moderating the relationship between engagement and cognition in either direction. Structural equation models provided further summary evidence that the relationships among engagement at Wave 1, extroversion, openness, and cognition at Wave 2 were not strong. However, a strong limitation to these results was the measurement error associated with a new measure of engagement.
Date: December 2009
Creator: Starkweather, Jonathan
System: The UNT Digital Library
Cultural and Technical Perspectives on Winter Landscape (open access)

Cultural and Technical Perspectives on Winter Landscape

Winter Landscape is an interactive composition for erhu (Chinese two-stringed fiddle), flute, piano, and Max/MSP interactive computer music system. The total duration of the piece is approximately 15 minutes. Winter Landscape serves to demonstrate one particular approach to exploring the possibilities afforded in an interactive paradigm within a cross-cultural context. The work is intended to convey my personality and identity as a contemporary Chinese composer through diverse cultural and musical influences drawn to this particular piece while creating a balance between traditional and modern sounds. The influences of Chinese philosophy (especially Chán) and the essence of Chinese traditional music play a prominent role as demonstrated in the formation of structures, expressions, and concept of Yun in the work; these influences also play a great role in determining the instrumentation and basic pitch structures of the work. However, this work is equally influenced by techniques and practices of modern Western classical music. These diverse influences hopefully have resulted in a unique work that truly does represent a cross-synthesis of these varying influences. In Winter Landscape, the interaction that takes place between the computer and the live musician is intended to reveal the responsive human/machine relationships. The computer constantly shifts its roles …
Date: December 2009
Creator: Wang, Jing
System: The UNT Digital Library
Investigation of cryopreservation methods for adherent nerve cell networks in vitro. (open access)

Investigation of cryopreservation methods for adherent nerve cell networks in vitro.

Cryopreservation in suspension is commonplace for a variety of cell types. However, cryopreservation of adherent cells has achieved limited success. This research aimed to cryopreserve adherent nerve cell networks in vitro in a manner that preserved network morphology and physiology. Successful implementation would enable long term storage of adherent neuronal networks on microelectrode arrays and on-demand access for use in pharmacological and toxicological testing. Based upon morphological assessments, excellent post-thaw preservation was obtained and post-thaw cultures survived in a transitional medium for up to 3.5 hours. However, transitions to native culture medium post-thaw presented difficulties, ultimately resulting in necrosis. A discussion of methods to supplement the current research and increase post-thaw viability is included in the thesis.
Date: December 2009
Creator: Webb, Veronica Fine
System: The UNT Digital Library
The proposed Fastrill Reservoir in east Texas:  A study using geographic information systems. (open access)

The proposed Fastrill Reservoir in east Texas: A study using geographic information systems.

Geographic information systems and remote sensing software were used to analyze data to determine the area and volume of the proposed Fastrill Reservoir, and to examine seven alternatives. The controversial reservoir site is in the same location as a nascent wildlife refuge. Six general land cover types impacted by the reservoir were also quantified using Landsat imagery. The study found that water consumption in Dallas is high, but if consumption rates are reduced to that of similar Texas cities, the reservoir is likely unnecessary. The reservoir and its alternatives were modeled in a GIS by selecting sites and intersecting horizontal water surfaces with terrain data to create a series of reservoir footprints and volumetric measurements. These were then compared with a classified satellite imagery to quantify land cover types. The reservoir impacted the most ecologically sensitive land cover type the most. Only one alternative site appeared slightly less environmentally damaging.
Date: December 2009
Creator: Wilson, Michael Ray
System: The UNT Digital Library