Ab Initio and Density Functional Investigation of the Conformer Manifold of Melatonin and a Proposal for a Simple Dft-based Diagnostic for Nondynamical Correlation (open access)

Ab Initio and Density Functional Investigation of the Conformer Manifold of Melatonin and a Proposal for a Simple Dft-based Diagnostic for Nondynamical Correlation

In this work we address two problems in computational chemistry relevant to biomolecular modeling. In the first project, we consider the conformer space of melatonin as a a representative example of “real-life” flexible biomolecules. Geometries for all 52 unique conformers are optimized using spin-component scaled MP2, and then relative energies are obtained at the CCSD (T) level near the complete basis set limit. These are then used to validate a variety of DFT methods with and without empirical dispersion corrections, as well as some lower-level ab initio methods. Basis set convergence is found to be relatively slow due to internal C-H…O and C-H…N contacts. Absent dispersion corrections, many DFT functionals will transpose the two lowest conformers. Dispersion corrections resolve the problem for most functionals. Double hybrids yield particularly good performance, as does MP2.5. In the second project, we propose a simple DFT-based diagnostic for nondynamical correlation effects. Aλ= (1-TAE [ΧλC]/TAE[XC])/λ where TAE is the total atomization energy, XC the “pure” DFT exchange-correlation functional, and ΧλC the corresponding hybrid with 100λ% HF-type exchange. The diagnostic is a good predictor for sensitivity of energetics to the level of theory, unlike most of the wavefunction-based diagnostics. For GGA functionals, Aλ values approaching unity …
Date: August 2013
Creator: Fogueri, Uma
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Ability of Offenders with Psychopathic Traits to Simulate Cognitive and Affective Empathy (open access)

Ability of Offenders with Psychopathic Traits to Simulate Cognitive and Affective Empathy

The accurate assessment of psychopathy constitutes a critical component of forensic assessments addressing offender populations. Among the core characteristics of psychopathy, the interpersonal component of deception and empathic deficits are prominently observed in offenders with psychopathic traits. Given the negative consequences of being classified as a psychopath, offenders may be likely to minimize their psychopathic traits. In particular, no research has investigated whether offenders with psychopathic traits are able to simulate empathy in an effort to mask their cognitive or affective empathy deficits (e.g., lack of remorse about offenses). The present study aims to contribute to the literature with regard to the simulation of empathy. Using a mixed between- and within-subjects design, 81 male detainees were placed into (a) a low psychopathy group, (b) a moderate psychopathy group, or (c) a high psychopathy group based on the Psychopathy Checklist – Revised. For the within-subjects component, all offenders answered empathy questionnaires under genuine and simulation conditions. Results indicate the sample possessed cognitive empathy, but did not display affective empathy under genuine instructions. Under simulation instructions, participants significantly increased their scores on several empathy measures. The implications of simulated empathy and comparisons between groups regarding simulation abilities are discussed.
Date: August 2013
Creator: Robinson, Emily V.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Accessing the Power of Aesthetics in Human-computer Interaction (open access)

Accessing the Power of Aesthetics in Human-computer Interaction

In information systems design there are two schools of thought about what factors are necessary to create a successful information system. The first, conventional view holds that system performance is a key, so that efficiency characteristics such as system usability and task completion time are primary concerns of system designers. The second, emerging view holds that the visual design is also the key, so that visual interface characteristics such as visual appeal, in addition to efficiency characteristics, are critical concerns of designers. This view contends that visual design enhances system use. Thus, this work examines the effects of visual design on computer systems. Visual design exerts its influence on systems through two mechanisms: it evokes affective responses from IT users, such as arousal and pleasure and it influences individuals’ cognitive assessments of systems. Given that both affective and cognitive reactions are significant antecedents of user behaviors in the IT realm, it is no surprise that visual design plays a critical role in information system success. Human-computer-interaction literature indicates that visual aesthetics positively influences such information success factors as usability, online trust, user satisfaction, flow experience, and so on. Although academic research has introduced visual design into the Information Systems (IS) …
Date: August 2013
Creator: Chenyan, Xu
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Accountability in Schools:  a Study of High School Accountability Ratings and College Success (open access)

Accountability in Schools: a Study of High School Accountability Ratings and College Success

The purpose of this study was to determine the relationship between high school campus accountability ratings, college readiness indicators, and the percent of students who achieved first year college success. Correlation and multiple regression analyses were used to analyze the relationship between the variables. Data was analyzed for two-year and four-year postsecondary educational institutions which were divided by eight school district types. Regression analysis of the relationship between high school campus accountability ratings and the percent of students who achieved first year college success for four- year post secondary educational institutions revealed statistically significant results ranging from R2 =.179 to R2 = .220. Similar results were found for two-year post secondary educational institutions with statistically significant results ranging from R2 = .049 to R2 = .218. The results indicated negligible to small relationships between the variables. Regression results of the analysis for the relationship between college readiness indicators and the percent of students who achieved first year college success revealed statistically significant results for 2 - year post secondary educational institutions ranging from R2 = .077 to R2 = .596 and for 4 -year post secondary educational institutions ranging from R2 = .048 to R2 = .304. These results indicated …
Date: August 2013
Creator: Orsborn, Shannon
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Acculturation and Feminist Endorsement on Control of Health and Health Behaviors in Hispanic Females (open access)

Acculturation and Feminist Endorsement on Control of Health and Health Behaviors in Hispanic Females

Hispanic women are the fastest growing population in the United States. Thus, it is important to explore health disparities that affect this population and better understand potential causes. Several explanations have been proposed for disparities that exist including turning to cultural alternatives rather than conventional medicine, low numbers of health insurance enrollments among Hispanics, and acculturation. However, little attention has been given to explanations that take into account the unique experiences of Hispanic women. The present study explored these experiences through investigation of endorsement of feminist attitudes (e.g., gender role adherence and beliefs that men and women should be treated equally in society) and level of acculturation. Undergraduate Hispanic women (18-24 years of age, M = 20.25, SD = 1.51) at the University of North Texas completed measures including the Multidimensional Health Questionnaire, the Acculturation Rating Scale for Mexican Americans-II, and the Liberal Feminist Attitude and Ideology Scale. Although results indicate that acculturation was not significant in the sample, feminist endorsement was found to be positively correlated with health-esteem, health-efficacy, and internal-health locus of control. Limitations and recommended directions for future research are explored.
Date: August 2013
Creator: Garner, Ashley Nicole
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Accuracy and Interpretability Testing of Text Mining Methods (open access)

Accuracy and Interpretability Testing of Text Mining Methods

Extracting meaningful information from large collections of text data is problematic because of the sheer size of the database. However, automated analytic methods capable of processing such data have emerged. These methods, collectively called text mining first began to appear in 1988. A number of additional text mining methods quickly developed in independent research silos with each based on unique mathematical algorithms. How good each of these methods are at analyzing text is unclear. Method development typically evolves from some research silo centric requirement with the success of the method measured by a custom requirement-based metric. Results of the new method are then compared to another method that was similarly developed. The proposed research introduces an experimentally designed testing method to text mining that eliminates research silo bias and simultaneously evaluates methods from all of the major context-region text mining method families. The proposed research method follows a random block factorial design with two treatments consisting of three and five levels (RBF-35) with repeated measures. Contribution of the research is threefold. First, the users perceived a difference in the effectiveness of the various methods. Second, while still not clear, there are characteristics with in the text collection that affect the …
Date: August 2013
Creator: Ashton, Triss A.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Accurate and Reliable Prediction of Energetic and Spectroscopic Properties Via Electronic Structure Methods (open access)

Accurate and Reliable Prediction of Energetic and Spectroscopic Properties Via Electronic Structure Methods

Computational chemistry has led to the greater understanding of the molecular world, from the interaction of molecules, to the composition of molecular species and materials. Of the families of computational chemistry approaches available, the main families of electronic structure methods that are capable of accurate and/or reliable predictions of energetic, structural, and spectroscopic properties are ab initio methods and density functional theory (DFT). The focus of this dissertation is to improve the accuracy of predictions and computational efficiency (with respect to memory, disk space, and computer processing time) of some computational chemistry methods, which, in turn, can extend the size of molecule that can be addressed, and, for other methods, DFT, in particular, gain greater insight into which DFT methods are more reliable than others. Much, though not all, of the focus of this dissertation is upon transition metal species – species for which much less method development has been targeted or insight about method performance has been well established. The ab initio approach that has been targeted in this work is the correlation consistent composite approach (ccCA), which has proven to be a robust, ab initio computational method for main group and first row transition metal-containing molecules yielding, on …
Date: August 2013
Creator: Laury, Marie L.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Adolescent Task Management: Multitasking and Social Media in the Student Search Process (open access)

Adolescent Task Management: Multitasking and Social Media in the Student Search Process

This study examines adolescent students at an American international school and observes student use of social networking programs as well as physical actions in the search process. The study specifically observed multitasking behavior and organizational skills among students, as well as linkages made through social networking sites. Student observations, student interviews, analysis of Facebook entries, and a survey on multitasking yielded rich data. Students appear to be far more organized than previously suggested in the literature, and in this study, the organization proved to be largely self-taught. Students used their social networks to build a kind of group expertise that compensated for their youthful naivety. Students exhibited self-control within the search to the degree that they could focus on what they wanted to find, and they used heuristics—mental shortcuts—to achieve what they needed. Searches also suggest creativity in that students were flexible in their search methods and used a number of tools to gather information. Students could balance the needs of the academic or imposed search with their own online lives, meaning that they made compensations for social media and media multitasking when it was deemed necessary.
Date: August 2013
Creator: Kurtenbach, John
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Adventure Based Counseling: Exploring the Impact of Abc on Adaptive Functioning in High School Males (open access)

Adventure Based Counseling: Exploring the Impact of Abc on Adaptive Functioning in High School Males

The purpose of this study was to examine the impact of ABC on adaptive functioning in high school males. Specifically, a pretest/posttest, experimental design (N = 46; Caucasian = 26, Hispanic = 20) was used to examine the changes in adaptive and maladaptive functioning in ABC participants (n = 21) compared to those in a control/waitlist group (n = 25) as measured by the Behavior Assessment System for Children, second edition (BASC-2). Participants randomly assigned to the treatment group engaged in 10 ABC sessions. In order to better understand group process in ABC, I had experimental group participants complete the Group Climate Question Short form (GCQ-S) three times during the intervention. A mixed between/within subjects ANOVA of the BASC-2 scores revealed a statistically significant increase in adaptive functioning for both groups, F(1, 33) = 8.58, p < .01, with a partial eta squared of .21 indicating a large effect. There was no statistically significant difference between the experimental and control/waitlist groups, F(1, 33) = .064, p = .80, and a very small effect size (partial eta squared < .01). A repeated measures ANOVA of the GCQ-S scores revealed a statistically significant increase in engagement, F(2, 38) = 4.067, p = …
Date: August 2013
Creator: Christian, David D.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Alchemies (open access)

Alchemies

This thesis consists of a collection of poems and a critical preface. The preface is a discussion of Elizabeth Bishop's descriptive mode, as demonstrated by three of her poems: "Sandpiper," "The Monument," and "Santarém." I argue for Bishop's descriptions as creative acts, and examine the gestures that help her make the reader aware of the shaping power she exercises.
Date: August 2013
Creator: Heffner, Christopher Daniel
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Altruism and Depression: Exploring This Relationship and the Mechanisms Behind It (open access)

Altruism and Depression: Exploring This Relationship and the Mechanisms Behind It

The impact of environmental influences on depression has been well established by research. In particular, it is known that receiving/perceiving adequate social support has a protective influence on depression. Less is known about the protective benefits of providing support to others, namely in the form of altruistic, empathetic, or prosocial behavior. While research has shown that having altruistic attitudes and engaging in altruistic behaviors has a positive impact on physical health and mental well-being, studies on the association between altruistic attitudes and/or behavior and depression are limited. The present study examined the relationship between altruism and depression, and hypotheses were tested that allow for explanation of why altruism may protect against depression. A sample of 303 participants was recruited from the University of North Texas and the surrounding community. Participants completed an online survey that examined their altruistic activities, details regarding these activities, their prosocial attitudes, and their current level of depression. Results did not support that level of involvement in altruistic activities is directly related to depression severity. However, outcomes from involvement in altruistic activities, including sense of overburden from participating in altruistic activities, level of social interaction with other helpers and those helped during altruistic activities, and sense …
Date: August 2013
Creator: Wright, Brittney, C.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Analysis of the Value-altering Effect of Motivating Operations (open access)

An Analysis of the Value-altering Effect of Motivating Operations

Motivating operations (MOs) may affect behavior in two ways; A) an MO momentarily alters the frequency of behavior for which a particular consequence has served as reinforcement (evocative-effect) and B) an MO momentarily alters the behavioral effects of the relevant consequence (value-altering effect). Many studies have empirically demonstrated the evocative function of MOs, however, few if any studies have attempted to systematically manipulate and measure the value-altering effect. The focus of this study was to investigate the value-altering effect by measuring choice and response allocation across two alternative tasks. Participants were two female girls diagnosed with autism. During conditioning sessions, experimenters created a history for the children in which clicking on a moving square on a computer monitor produced a small piece of edible. Prior to some conditions, the participants were allowed 5 min of free-access to the edibles, and in other sessions, access to edibles prior to session was restricted. During these sessions, the square was either red or blue depending on the condition type (pre-access or restricted-access). During probe sessions, both colored squares were concurrently available and participants were allowed to allocate their responding to whichever square they chose. One participant preferred the square associated with restricted-access, which …
Date: August 2013
Creator: Devine, Bailey
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Analyzing Patterns Within Academic and Legal Definitions: a Qualitative Content Analysis of the Term "Cyberbullying" (open access)

Analyzing Patterns Within Academic and Legal Definitions: a Qualitative Content Analysis of the Term "Cyberbullying"

Regardless of culture or nation, students today are experiencing bullying via technology. With the rise of technology, this abuse has the ability to become more far-reaching, and more pervasive than ever. These students face oppression, and in some cases severe imbalances of power. Current research is being conducted and laws created based on varying operational and conception definitions of the term "cyberbullying." This study aims to analyze and provide a coherent definition for the term "cyberbullying" as it is used in research and legislation, especially in the context of today's educational environments. The results help shed light on the large variances in the term and suggestions are made to clarify the definition as the field continues to move forward.
Date: August 2013
Creator: Winn, Matthew R.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Attention and Metacognition in the Elaborated Intrusion Theory of Desire (open access)

Attention and Metacognition in the Elaborated Intrusion Theory of Desire

The elaborated intrusion (EI) theory of desire is a cognitive model that describes the processes involved in craving as intrusive thoughts that are elaborated upon leading to dissonance when desires are not met. While the theory is based on a wide body of research, certain theoretical predictions have not been fully examined. Specifically, EI theory argues that mental imagery has a central role in craving, and predicts that attempts to suppress substance-related intrusive thoughts and mental imagery is related to increased craving. Further, EI theory suggests that elaboration of craving imagery is related to attention and working memory processes, however, there are questions about whether differential performance in these domains is related to craving. The current study examined the relationship between attention/working memory performance and alcohol craving in a sample of 119 young adult males. Additionally, metacognition was examined to clarify the phenomenological aspects of craving within EI theory. Attention and working memory performance did not significantly predict intrusive thought and mental imagery elaboration. Individuals with high craving reported significantly higher levels of anxiety, thought suppression, and greater strength and frequency of craving-related mental imagery. They were also more likely to try to control their own thoughts and make negative …
Date: August 2013
Creator: Yates, Robert D., III
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Automated Real-time Objects Detection in Colonoscopy Videos for Quality Measurements (open access)

Automated Real-time Objects Detection in Colonoscopy Videos for Quality Measurements

The effectiveness of colonoscopy depends on the quality of the inspection of the colon. There was no automated measurement method to evaluate the quality of the inspection. This thesis addresses this issue by investigating an automated post-procedure quality measurement technique and proposing a novel approach automatically deciding a percentage of stool areas in images of digitized colonoscopy video files. It involves the classification of image pixels based on their color features using a new method of planes on RGB (red, green and blue) color space. The limitation of post-procedure quality measurement is that quality measurements are available long after the procedure was done and the patient was released. A better approach is to inform any sub-optimal inspection immediately so that the endoscopist can improve the quality in real-time during the procedure. This thesis also proposes an extension to post-procedure method to detect stool, bite-block, and blood regions in real-time using color features in HSV color space. These three objects play a major role in quality measurements in colonoscopy. The proposed method partitions very large positive examples of each of these objects into a number of groups. These groups are formed by taking intersection of positive examples with a hyper plane. …
Date: August 2013
Creator: Kumara, Muthukudage Jayantha
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Blueline Concerto: Critical Essay (open access)

Blueline Concerto: Critical Essay

The purpose of this critical essay is two-fold. First, the essay presents a detailed critical analysis of my original composition, Blueline Concerto for bass trombone and wind ensemble. Second, using Blueline Concerto, the essay presents preliminary findings of my study to develop an approach to composing that takes into account the musicians' health, specifically regarding noise induced hearing loss (NIHL). Through various hypothesized composition- and orchestral-based approaches, I test effectiveness on changes in NIHL risk while also noting that artistic merit and compositional integrity is preserved.
Date: August 2013
Creator: Lamb, Christopher
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Britten’s Op 47, Five Flower Songs: Breaking Trends in Analysis (open access)

Britten’s Op 47, Five Flower Songs: Breaking Trends in Analysis

Benjamin Britten’s life and music have been the subject of study from early in his musical career. Current trends in psychological analysis of Britten’s music tend to focus on common themes, such as homosexuality, pacifism, the sense of the outsider, and the loss of innocence. Similarly, theoretical analyses tend either to provide general categorizations of the technical elements in Britten’s music or to apply a singular preconceived concept as a tool for understanding his compositions. These approaches have yielded significant information but leave aspects of Britten’s personality and music unilluminated. Britten’s Op. 47, Five Flower Songs, are a collection of five part songs for a cappella chorus that are often included within the canon of 20th century choral literature. This paper examines a new perspective on Britten’s music by examining the relationship between Britten’s friendships and their influence on his compositions. Through the examination of these relationships information is revealed that allows for a new method of analysis that is particularly relevant to the Five Flower Songs. The opus was dedicated to two botanists for the occasion of their 25th wedding anniversary. Contained within specific movements are extra-musical references to scientific characteristics of the flowers that are the subjects of …
Date: August 2013
Creator: Jackson, Christopher Michael
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Centers of Invariant Differential Operator Algebras for Jacobi Groups of Higher Rank (open access)

Centers of Invariant Differential Operator Algebras for Jacobi Groups of Higher Rank

Let G be a Lie group acting on a homogeneous space G/K. The center of the universal enveloping algebra of the Lie algebra of G maps homomorphically into the center of the algebra of differential operators on G/K invariant under the action of G. In the case that G is a Jacobi Lie group of rank 2, we prove that this homomorphism is surjective and hence that the center of the invariant differential operator algebra is the image of the center of the universal enveloping algebra. This is an extension of work of Bringmann, Conley, and Richter in the rank 1case.
Date: August 2013
Creator: Dahal, Rabin
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Central Office Administrators' Perceptions of the Professional Learning Community Process (open access)

Central Office Administrators' Perceptions of the Professional Learning Community Process

This study provides a qualitative interpretation of the work done by central office administrators in a school district in Texas as they supported and built capacity for the professional learning community (PLC) process over a five year time period. Literature by PLC scholars, especially R. DuFour, R.B. DuFour, Eaker, Hord, Hipp, Huffman, and Olivier, informed development of the study. In a school district of 19,000 students and 2,000 staff members, ten central office administrators were interviewed to gain their perceptions of their roles in the PLC process. Interviews were analyzed through the processes of initial, focused, and theoretical coding. Documents were examined and used as supplemental sources of data to corroborate the perspectives provided. Findings revealed the story of central office administrators who worked interdependently to support and build capacity in the implementation and sustainment of the PLC process. A thick description of the work based on their perceptions offers actions and behaviors of administrators specific to their roles and practices and protocols developed to hold the work together. A grounded theory was developed with regard to central office administrators' support and capacity-building for the PLC process. From the administrators' perceptions, six theoretical categories relating to central office support and …
Date: August 2013
Creator: Pruitt, Mary E.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Comparative Phyto-uptake Across Distribution Coefficients of Pharmaceutical Compounds and Aquatic Macrophytes: Carbamazepine and Amiodarone Uptake in Lemna Spp (open access)

Comparative Phyto-uptake Across Distribution Coefficients of Pharmaceutical Compounds and Aquatic Macrophytes: Carbamazepine and Amiodarone Uptake in Lemna Spp

Few studies have been conducted on the effectiveness of phytoremediation of pharmaceutical compounds, although the persistent and non-acutely toxic nature of many of these compounds in today's water bodies may yield an ideal application for this practice. To quantify the potential effectiveness of plant uptake, kinetic and proportional bioconcentration factors (BCFk, and BCFp, respectively) in nanograms (ng) carbamazepine and amiodarone per gram (g) wet weight plant tissue for Lemna spp. were determined utilizing a 14-day continuous flow-through study. Samples were analyzed using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) running in positive ion mode. Kinetic BCF was estimated at 0.538, while proportional BCF was estimated at 0.485. Kinetic BCF for the amiodarone study was estimated at 23.033, whereas proportional BCF was estimated at 41.340. Possible contamination of the C18 column and peristaltic pump failure may have impacted uptake results. In light of variability and current lack of research in the field, this work should be considered exploratory rather than conclusive.
Date: August 2013
Creator: Woodard, Jennifer Kristin
Object Type: Thesis or Dissertation
System: The UNT Digital Library
A Comparative Study of Non Linear Conjugate Gradient Methods (open access)

A Comparative Study of Non Linear Conjugate Gradient Methods

We study the development of nonlinear conjugate gradient methods, Fletcher Reeves (FR) and Polak Ribiere (PR). FR extends the linear conjugate gradient method to nonlinear functions by incorporating two changes, for the step length αk a line search is performed and replacing the residual, rk (rk=b-Axk) by the gradient of the nonlinear objective function. The PR method is equivalent to FR method for exact line searches and when the underlying quadratic function is strongly convex. The PR method is basically a variant of FR and primarily differs from it in the choice of the parameter βk. On applying the nonlinear Rosenbrock function to the MATLAB code for the FR and the PR algorithms we observe that the performance of PR method (k=29) is far better than the FR method (k=42). But, we observe that when the MATLAB codes are applied to general nonlinear functions, specifically functions whose minimum is a large negative number not close to zero and the iterates too are large values far off from zero the PR algorithm does not perform well. This problem with the PR method persists even if we run the PR algorithm for more iterations or with an initial guess closer to the …
Date: August 2013
Creator: Pathak, Subrat
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Comparison of Learning Performance Between Students Who Do and Students Who Do Not Use Mobile Technology-based Activities (open access)

Comparison of Learning Performance Between Students Who Do and Students Who Do Not Use Mobile Technology-based Activities

This study examined if using mobile technology-based activities would increase student performance in biological science courses. The study compared two groups of students in lectures and labs. Each group had about 20 students. The mobile group had mobile technology-based activities and the non-mobile group received conventional instruction. The mobile group used links to the website, or a QR Code to access the activities. The non-mobile group had handouts and worksheets over the same content. The research methodology for this study was mixed method. The study was a quasi-experimental design that used instruction method as the independent variable between two groups. The study used formative and summative assessment to compare the performance of the mobile group and non-mobile group in lecture and lab. The student in the mobile group had statistically significantly higher lab exam scores than students in the non-mobile group. Additionally, Students were surveyed about their performance expectancy and effort expectancy using mobile technology for learning, and they were asked about their self-management of learning. Analysis indicated that both groups had similar performance and effort expectancy using mobile technology for learning, but the two groups differed on self-management of learning responses to the survey. Focus groups from the mobile …
Date: August 2013
Creator: Stowe, William A., Jr.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Computational Studies of Inorganic Systems with a Multiscale Modeling Approach: From Atomistic to Continuum Scale (open access)

Computational Studies of Inorganic Systems with a Multiscale Modeling Approach: From Atomistic to Continuum Scale

Multiscale modeling is an effective tool for integrating different computational methods, creating a way of modeling diverse chemical and physical phenomena. Presented are studies on a variety of chemical problems at different computational scales and also the combination of different computational methods to study a single phenomenon. The methods used encompass density functional theory (DFT), molecular dynamics (MD) simulations and finite element analysis (FEA). The DFT studies were conducted both on the molecular level and using plane-wave methods. The particular topics studied using DFT are the rational catalyst design of complexes for C—H bond activation, oxidation of nickel surfaces and the calculation of interaction properties of carbon dioxide containing systems directed towards carbon dioxide sequestration studies. Second and third row (typically precious metals) transition metal complexes are known to possess certain electronic features that define their structure and reactivity, and which are usually not observed in their first-row (base metal) congeners. Can these electronic features be conferred onto first-row transition metals with the aid of non-innocent and/or very high-field ligands? Using DFT, the impact of these electronic features upon methane C—H bond activation was modeled using the dipyridylazaallyl (smif) supporting ligand for late, first-row transition metal (M) imide, oxo and …
Date: August 2013
Creator: Olatunji-Ojo, Olayinka A.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Confirming the Constructs of the Adlerian Personality Priority Assessment (Appa) (open access)

Confirming the Constructs of the Adlerian Personality Priority Assessment (Appa)

The primary purpose of this study was to confirm the four-factor structure of the 30-item Adlerian Personality Priority Assessment (APPA) using a split-sample cross-validation confirmatory factor analysis (CFA). The APPA is an assessment, grounded in Adlerian theory, used to conceptualize clients based on the four personality priorities most commonly used in the Adlerian literature: superiority, pleasing, control, and comfort. The secondary purpose of this study was to provide evidence for discriminant validity, examine predictive qualities of demographics, and explore the prevalence of the four priorities across demographics. For the cross validation CFA, I randomly divided the sample, 1210 undergraduates, at a large public research university (53% Caucasian, 13.1% Hispanic/Latino(a), 21.4% African American, 5.4% American Indian, and 5.8% biracial; mean age =19.8; 58.9% females), into two equal subsamples. I used Subsample 1 (n = 605) to conduct the initial CFA. I held out Subsample 2 (n = 605) to test any possible model changes resulting from Subsample 1 results and to provide further confirmation of the APPA's construct validity. Findings from the split-sample cross-validation CFA confirmed the four-factor structure of the APPA and provided support for the factorial/structure validity of the APPA's scores. Results also present initial evidence of discriminant validity …
Date: August 2013
Creator: Dillman Taylor, Dalena
Object Type: Thesis or Dissertation
System: The UNT Digital Library