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Meta-Analysis of the Impact of After-School Programs on Students Reading and Mathematics Performance (open access)

Meta-Analysis of the Impact of After-School Programs on Students Reading and Mathematics Performance

The purpose of this study employing meta-analysis was to assess the impact that after-school programs have on reading and mathematics outcomes. The participants in the primary studies were students in Grades K through 8; years 200 through 2009. The study utilized the theory of change as its theoretical basis. This meta-analysis used the effect size as the standard measure. It began with an overall Cohen's d of .40 for the impact that after-school programs have on reading and mathematics outcomes, and then proceeded to analyze three moderator variables: subject, time periods, and grade level.The findings of the meta-analysis, both overall and sub analyses, show that the independent variable, after-school programs, has an impact on the dependent variable, reading and mathematics. The overall results indicated that after-school programs are educationally significant in the areas of reading and mathematics combined. As for the moderator variable, the results for the areas of (a) subject (reading and mathematics), (b) time period (2000-2002, 2003-2005 and 2006-2009), and (c) grade (middle, and middle plus elementary combined), all indicated educationally significant results. The notable exception was the grade moderator, elementary.This study provides more information for researchers, practitioners and policy makers upon which to make practical research based …
Date: May 2011
Creator: Crawford, Stanley T.
System: The UNT Digital Library
Structural Validity and Item Functioning of the LoTi Digital-Age Survey. (open access)

Structural Validity and Item Functioning of the LoTi Digital-Age Survey.

The present study examined the structural construct validity of the LoTi Digital-Age Survey, a measure of teacher instructional practices with technology in the classroom. Teacher responses (N = 2840) from across the United States were used to assess factor structure of the instrument using both exploratory and confirmatory analyses. Parallel analysis suggests retaining a five-factor solution compared to the MAP test that suggests retaining a three-factor solution. Both analyses (EFA and CFA) indicate that changes need to be made to the current factor structure of the survey. The last two factors were composed of items that did not cover or accurately measure the content of the latent trait. Problematic items, such as items with crossloadings, were discussed. Suggestions were provided to improve the factor structure, items, and scale of the survey.
Date: May 2011
Creator: Mehta, Vandhana
System: The UNT Digital Library
The Lexicographer's Daughter: A Memoir (open access)

The Lexicographer's Daughter: A Memoir

This creative nonfiction dissertation is a memoir of the author's search for the somewhat mysterious hidden past of her father, the lexicographer Charles J. Lovell, who died in 1960, when the author was nine. Her father's early death left the author with many unanswered questions about his past and his family and so she undertakes a search to answer, if possible, some of those questions. Her search takes her to Portland, Maine; New Bedford, Massachusetts; and Pasadena, California, where she tries to discover the facts and uncover the forces that shaped her father's life. Along the way, she realizes how profoundly his death affected and shaped her own life, contributing to the theme of loss that pervades the memoir. In addition, she begins to realize how much her mother, Dixie Hefley Lovell, whose significance she previously overlooked, shaped her life. Ultimately, she comes to understand and accept that some of her questions are unanswerable.
Date: May 2011
Creator: Lovell, Bonnie Alice
System: The UNT Digital Library
A Comparative Study of Two Single-Subject Keyboard Ricercare by Johann Jacob Froberger: Projections of Sixteenth-Century Practice Combined with Features that Forecast Baroque Practice (open access)

A Comparative Study of Two Single-Subject Keyboard Ricercare by Johann Jacob Froberger: Projections of Sixteenth-Century Practice Combined with Features that Forecast Baroque Practice

This study is focused on an analysis of two single-subject ricercare in the keyboard music of Johann Jacob Froberger and examines possible pathways to the development of the Baroque fugue. This dissertation is divided into three parts. Chapter I contains the purpose, significance of this study and composer, as well as characteristics of the seventeenth-century single-subject ricercar. Chapter II details and examines Froberger's two ricercare. Finally, a conclusion of this study is presented in Chapter III. Two appendixes are included in this dissertation: a list of the single-subject ricercare of Andrea Gabrieli, Giovanni Gabrieli, and Johann Jacob Froberger; and an analysis of the two single-subject ricercare, FbWV 407 and FbWV 409, by Johann Jacob Froberger.
Date: May 2011
Creator: Lee, WoongHee
System: The UNT Digital Library
Contemporary Research on Child-Centered Play Therapy (CCPT) Modalities: A Meta-Analytic Review of Controlled Outcome Studies (open access)

Contemporary Research on Child-Centered Play Therapy (CCPT) Modalities: A Meta-Analytic Review of Controlled Outcome Studies

The present meta-analytic study estimated the overall effectiveness of child therapy interventions using CCPT methodology and explored the relationships between study characteristics and treatment effects. Fifty-two studies between 1995 and the present were included based on the following criteria: (a) the use of CCPT methodology, (b) the use of control or comparison repeated measure design, (c) the use of standardized psychometric assessment, and (d) clear reports of effect sizes or sufficient information for effect size calculation. Hierarchical linear modeling (HLM) techniques were utilized to estimate the overall effect size for the collected studies and explore relationships between effect sizes and study characteristics. Dependent variable included 239 effect sizes, and independent variables included 22 study characteristics. The mean age of all child participants in the collected studies was 6.7. In 15 studies, the majority of participants were Caucasian. An equal number of studies were made up of non-Caucasian participants, including 3 with majority African American, 4 with majority Hispanic/Latino participants, 5 with majority Asian/Asian American participants, and 3 with other ethnic populations. Study collection included 33 studies with majority of boys and 11 studies with majority of girls. HLM analysis estimated a statistically significant overall effect size of 0.47 for the …
Date: May 2011
Creator: Lin, Yung-Wei (Dennis)
System: The UNT Digital Library
An Ecological Understanding of Teacher Quality in Early Childhood Programs: Implications and Recommendations (open access)

An Ecological Understanding of Teacher Quality in Early Childhood Programs: Implications and Recommendations

This research examined whether or not relationships exist between preschool teacher quality and parent involvement as indicated by the Hoover-Dempsey and Sandler Model of Parent Involvement Survey. Additionally, the study also considered family income and child membership in special education as predictors of parent involvement. The survey instruments included the Early Childhood Environmental Rating Scale, Revised (ECERS-R) and the Hoover-Dempsey and Sandler Parent Involvement Survey. A total of 306 parents across 35 preschool classrooms participated in the study. Effect sizes, beta weights and structure coefficients from a series of multiple regression analyses measured the relationship between variables. A regression equation comprised of teacher quality, family income and child membership in special education was statistically significant in predicting parent school-based involvement. In the school-based involvement model the predictors teacher quality and child membership in special education accounted for a greater percentage of variance than did family income. Teacher quality demonstrated a small, negative beta weight but accounted for the greatest amount of variance among the three predictors within the school-based parent involvement model. A negative relationship between teacher quality and school-based parent involvement suggested that as teacher quality improved, parents reported less involvement in school-based activities and events. Findings for special …
Date: May 2011
Creator: Macias-Brown, Armandina A.
System: The UNT Digital Library
Exploring Critical Factors in Predicting Post-Adoptive Use of Facebook (open access)

Exploring Critical Factors in Predicting Post-Adoptive Use of Facebook

Social networking applications (SNAs) have experienced a boom in popularity in recent years. Sites like Facebook and MySpace continuously draw new users, and are successful in organizing groups of users around topics of common interest. Among SNAs, Facebook has demonstrably outgrown its rivals growing an estimated 157 percent from 2008 to 2009. Facebook is now estimated to be the fourth largest Internet site in the world, trailing only Google, Microsoft and Yahoo (Schonfeld 2009). This dissertation posits and tests a theoretical model composed of key factors that contribute to post-adoptive use of social networking applications and the relationship of those factors to one another. This study also identifies and clarifies new constructs that were not previously used to measure usage, and further refines the constructs that were previously used so that they better fit social networking applications. The results of this dissertation show that the critical factors of social capital, hedonic enjoyment, perceived usefulness, social influence, satisfaction and attitude have a positive influence on a post-adoptive user's intention to continue using Facebook. The results of this study yielded a structural model for predicting the post-adoptive use of Facebook. This work also developed an instrument for measuring constructs relevant to social …
Date: May 2011
Creator: Magro, Michael J.
System: The UNT Digital Library
The Influence of Ohmic Metals and Oxide Deposition on the Structure and Electrical Properties of Multilayer Epitaxial Graphene on Silicon Carbide Substrates (open access)

The Influence of Ohmic Metals and Oxide Deposition on the Structure and Electrical Properties of Multilayer Epitaxial Graphene on Silicon Carbide Substrates

Graphene has attracted significant research attention for next generation of semiconductor devices due to its high electron mobility and compatibility with planar semiconductor processing. In this dissertation, the influences of Ohmic metals and high dielectric (high-k) constant aluminum oxide (Al2O3) deposition on the structural and electrical properties of multi-layer epitaxial graphene (MLG) grown by graphitization of silicon carbide (SiC) substrates have been investigated. Uniform MLG was successfully grown by sublimation of silicon from epitaxy-ready, Si and C terminated, 6H-SiC wafers in high-vacuum and argon atmosphere. The graphene formation was accompanied by a significant enhancement of Ohmic behavior, and, was found to be sensitive to the temperature ramp-up rate and annealing time. High-resolution transmission electron microscopy (HRTEM) showed that the interface between the metal and SiC remained sharp and free of macroscopic defects even after 30 min, 1430 °C anneals. The impact of high dielectric constant Al2O3 and its deposition by radio frequency (RF) magnetron sputtering on the structural and electrical properties of MLG is discussed. HRTEM analysis confirms that the Al2O3/MLG interface is relatively sharp and that thickness approximation of the MLG using angle resolved X-ray photoelectron spectroscopy (ARXPS) as well as variable-angle spectroscopic ellipsometry (VASE) is accurate. The totality …
Date: May 2011
Creator: Maneshian, Mohammad Hassan
System: The UNT Digital Library
School Governance and Student Achievement: Revealing Factors Beyond the McCarty-Ramsey Model (open access)

School Governance and Student Achievement: Revealing Factors Beyond the McCarty-Ramsey Model

The purpose of this study was to identify and investigate the specific superintendent leadership type and underlying factors that support significant student achievement gains in communities where misalignment with the McCarty-Ramsey model exists. Utilizing a mixedmethod research strategy, contributing school districts were identified through a survey developed by McCarty and Ramsey. This survey indicated that districts could show positive student achievement gains while exhibiting misalignment among these factors. While all four types of superintendent leadership style were revealed in the survey, a prevalent superintendent leadership types was associated with the misaligned districts showing significant academic growth. This study indicated the professional advisor or the professional advisor/decision maker superintendent had the greatest achievement results in misaligned districts. The second investigation phase involved school districts that met two criteria: misalignment with the McCarty-Ramsey model, and three years of significant student achievement gains, as measured by the California Academic Performance Indicator. Interviews were conducted with identified school board presidents and superintendents to reveal practices or initiatives promoting these results. The interview protocol consisted of a series of open-ended questions regarding effective leadership and programs. The second finding revealed the effective superintendent focuses efforts on five specific district leadership actions identified by researchers such …
Date: May 2011
Creator: Kemp, Stella Maria
System: The UNT Digital Library
Style and Satisfaction: An Examination of the Relationship Between Instructor Communicator Style and Instructor Job Satisfaction (open access)

Style and Satisfaction: An Examination of the Relationship Between Instructor Communicator Style and Instructor Job Satisfaction

The study sample was composed of 110 teaching faculty at Vernon College, a multi-campus northwest Texas community college in Wichita Falls, TX. Participants completed two surveys: the Socio-communicative Orientation Scale (SCO) and the Teacher Satisfaction Scale (SAT). Demographic information was collected as well for generalizability purposes. As measured by the SCO, communicator style is a multi-dimensional concept including aspects of assertiveness and responsiveness communication behaviors; the assertiveness and responsiveness dimensions acted as independent variables. Instructor job satisfaction acted as the independent variable. The strength of the independent variables was measured separately in ratio to job satisfaction. Regression analysis results demonstrated that the assertiveness dimension of instructor communicator style is not a statistically significant contributor to instructor satisfaction. However, the responsiveness dimension can explain 12% of the variance in instructor job satisfaction. Beta weight and structure coefficient analysis confirmed the initial regression results for both independent variables. Further, commonality analysis clarified that the two independent variables within the study are in fact orthogonal in nature, meaning that they do not overlap and are not correlated. Hence, the responsiveness dimension of instructor communicator style is directly related to relationship building in an educational context and may be considered in professional development activities. …
Date: May 2011
Creator: Kirk, Don DeWayne
System: The UNT Digital Library
Evocations from Childhood: Stylistic Influences and Musical Quotations in Claude Debussy's Children's Corner and La Boîte À Joujoux (open access)

Evocations from Childhood: Stylistic Influences and Musical Quotations in Claude Debussy's Children's Corner and La Boîte À Joujoux

Claude Debussy is considered one of the most influential figures of the late 19th century and early 20th centuries. Among the various works that he wrote for the piano, Children's Corner and La Boîte à joujoux distinguish themselves as being evocative of childhood. However, compared to more substantial works like Pelléas et Mélisande or La Mer, his children's piano music has been underrated and seldom performed. Children's Corner and La Boîte à joujoux were influenced by a series of eclectic sources, including jazz, novel "views" from Russian composers, and traditional musical elements such as folk songs and Eastern music. The study examines several stylistic parallels found in these two pieces and is followed by a discussion of Debussy's use of musical quotations and allusions, important elements used by the composer to achieve what could be dubbed as a unique "children's wonderland."
Date: May 2011
Creator: Ko, Hsing-Yin
System: The UNT Digital Library
Effects of Using Logic and Spatial Cybergames to Improve Student Success Rates in Lower-Division Chemistry Courses (open access)

Effects of Using Logic and Spatial Cybergames to Improve Student Success Rates in Lower-Division Chemistry Courses

A study was conducted to investigate the relationships between cybergaming treatment groups and the control group (N = 99: ncontrol = 8; nlogic = 29; nspatial = 30; ncombination = 32) with success in the organic chemistry I course as measured by achievement over a 10-week period. The treatment groups included logic training, spatial training, and combination logic-spatial training. Students' ability was measured by pre/post exams using the Group Assessment of Logical Thinking (GALT) to measure logic ability, Purdue Visualizations of Rotations (ROT) test to measure spatial skills, and the General-Organic-Biochemistry (GOB) Exam to measure content attainment. Finally, students' responses about participation in this experience were evaluated using open- and closed-ended questions on a self-developed survey. A second study was conducted to evaluate the relationship between the cybergaming treatment and control groups (N = 88: nexperimental = 27; ncontrol = 61) with success in the general chemistry I course as measured by achievement and final course averages and grades. The cybergaming treatment group underwent intensive combination logic-spatial training for 10 weeks. Students' progress was measured using three pre/post instruments: Group Assessment of Logical Thinking (GALT) measured logic ability, Purdue Visualizations of Rotations (ROT) Test measured spatial skills, and the California …
Date: May 2011
Creator: Manrique, Carissa Janice
System: The UNT Digital Library
The Federal Judiciary and Establishment Clause Jurisprudence:  Application of the Lemon Test since Mitchell v. Helms (open access)

The Federal Judiciary and Establishment Clause Jurisprudence: Application of the Lemon Test since Mitchell v. Helms

The issue of religion and its place in society has been a topic of controversy and debate since long before the creation of our constitutional republic. The relationship between religion and government has witnessed some of its most intense conflicts when the governmental entity in question involves public education. As our country moved into the 20th century, legal challenges in the field of public education began to emerge calling into question the constitutionality of various policies and practices at both the state and local levels. This dissertation examined the legal methodology that was initially developed and then subsequently modified as the judicial branch has interpreted how the Establishment Clause delineates the relationship between religion and public education. Because the United States Supreme Court has not overturned its decision in Lemon v. Kurtzman, the tri-partite test it established still remains the law of the land. Subsequent decisions by the Court leading up to their ruling in Mitchell v. Helms, however, have continued to modify the judiciary's approach toward the use of the Lemon test in Establishment Clause jurisprudence. This research analyzed the decisions of the various federal courts subsequent to the ruling issued in Mitchell to discern both the present position …
Date: May 2011
Creator: Sanders, Russell Scott
System: The UNT Digital Library
Design for Social Presence and Exploring Its Mediating Effect in Mobile Data Communication Services (open access)

Design for Social Presence and Exploring Its Mediating Effect in Mobile Data Communication Services

The mobility, flexibility, convenience, and ubiquity of mobile data services (MDS) have contributed to their enormous growth and popularity with users. MDS allow users to communicate through mobile texting (mTexting), mobile Instant Messaging (mIM), multimedia messaging services (MMS), and email. A unique feature of MDS that enhances its popularity among its users is the awareness capability, which is revolutionizing the way MDS is being used to communicate today. It allows potential communication partners to socialize through these technologies. This dissertation explored the relationship between user experience, perceived richness, perceived social presence and satisfaction with MDS. A research model for examining the antecedent conditions that influence social presence, richness, social interaction and satisfaction with MDS was developed. Partial least square analysis showed that user experience influenced both social presence and richness. Also supported was the relationship between richness, social presence and satisfaction with MDS. Social presence mediated the relationship between user experience and richness. However, only one dimension of interactivity influenced social presence.
Date: May 2011
Creator: Ogara, Solomon Omondi
System: The UNT Digital Library
A Critical Analysis of Ph.D. and Ed.D. Dissertation Abstracts Published during 2009 and 2010 (open access)

A Critical Analysis of Ph.D. and Ed.D. Dissertation Abstracts Published during 2009 and 2010

The completion of the dissertation certifies the completion of the academic rigors of the doctoral degree and verifies the candidate's achievement of independent scholarship. The Carnegie Project on the Education Doctorate was a 5-year effort to define the distinct purpose of the Ph.D. and Ed.D. in education. The Carnegie Project sought to ensure that the academy moved forward on two fronts: rethinking and reclaiming the research doctorate, the Ph.D., and developing the distinct professional practice doctorate, the Ed.D. The project determined that there has been a blurring of the distinctions between these two degrees over the past half-century which invites examination of their purpose and their content. Given this, this qualitative study examined Ph.D. and Ed.D. dissertation abstracts to determine if abstracts differ in terms of these selected factors: research design, data analysis, use of theoretical frameworks, subjects or participants, the setting or context of the study, and to compare Ph.D. and Ed.D. abstracts to the abstract format recommended in literature to explore if there are differences in the abstracts and to determine to what extent abstracts in either degree are congruent with the recommendations. This study used a digital dissertation database to study 100 Ed.D. dissertation abstracts and 100 …
Date: May 2011
Creator: Newsom, Thomas W.
System: The UNT Digital Library
Reproductive and Growth Responses of the Fathead Minnow (Pimephales Promelas) and Japanese Medaka (Oryzias Latipes) to the Synthetic Progestin, Norethindrone (open access)

Reproductive and Growth Responses of the Fathead Minnow (Pimephales Promelas) and Japanese Medaka (Oryzias Latipes) to the Synthetic Progestin, Norethindrone

A commonly prescribed contraceptive, the synthetic progestin norethindrone (NET) inhibits ovulation in humans. However, ecotoxicological data are lacking. Preliminary tests produced an LC50 for NET of > 1.0 mg/L (96-hour, fathead minnow (FHM) and medaka) and a NOEC of 242.0 µg/L, a LOEC of 485.0 µg/L (7-day, growth for FHM and medaka). Reproductive testing revealed a LOEC for fecundity of 24.1 ng/L (21 days, medaka). Further testing confirmed the LOEC of 24.1 ng/L while defining a NOEC of 4.7 ng/L (28 days, medaka). Effect of NET in medaka life-cycle exposure at concentrations exceeding 4.7 ng/L was evident. Few females were present in the 24.7 ng/L exposure concentration, with none in the 104.6 ng/L. Egg production was significantly reduced at concentrations exceeding 4.7 ng/L. Additionally, weight, condition factor and somatic indices were significantly different in males exposed to concentrations exceeding 4.7 ng/L. For fecundity and sexual differentiation; the NOEC was 4.7 ng/L, the LOEC 24.6 ng/L; growth and somatic indices, the NOEC was more appropriately 0.9 ng/L, with effect evident at 4.7 ng/L. Sexual differentiation of the F1 population was similar to the F0. A defining result of this test was development of exceptionally large ovaries in NET- exposed female medaka, …
Date: May 2011
Creator: Paulos, Peter M.
System: The UNT Digital Library
Assessment of Feigning with the Trauma Symptom Inventory: Development and Validation of new Validity Scales with Severely Traumatized Patients (open access)

Assessment of Feigning with the Trauma Symptom Inventory: Development and Validation of new Validity Scales with Severely Traumatized Patients

Currently, only the TSI assesses complex traumatic reactions and patient response styles. However, its feigning scale, ATR, uses a flawed detection strategy and is potentially confounded by experiences of complex PTSD. As a consequence, clinicians using the TSI to evaluate severely traumatized patients have no useful method for discriminating genuine and feigned responding. Several detection strategies have demonstrated utility within evaluations of feigned trauma including the assessment of rare symptoms, symptom combinations, symptom selectivity, and symptom severity. The current study created scales on the TSI according to these strategies using a development sample of 107 severely traumatized patients. Validation of all TSI feigning scales was then performed with a second independent sample of 71 severely traumatized patients using a mixed simulation design. Results found support for each scale's convergent validity with SIRS primary scales (M rs = .52) and discriminant validity with measures of defensiveness on the SIRS (M rs = -.07) and TSI (M rs = -.19). Each scale also produced expectedly mild to moderate relationships with SADS-C clinical scales (M rs = .32) and the SCID-IV PTSD module (M rs = -.02). Support for their criterion validity was only moderate (M ds = .69) when comparing the scores …
Date: May 2011
Creator: Payne, Joshua W.
System: The UNT Digital Library
Epidemiological Evaluation of Pain Among String Instrumentalists (open access)

Epidemiological Evaluation of Pain Among String Instrumentalists

Pain and performance anxiety (PA) are common problems among string players. Therefore, the purpose of this study was to assess and compare PA and prevalence rates and locations of pain in violinists, violists, cellists, and bassists. Subjects completed a questionnaire that included sections on demographics, musical background, practice habits, musculoskeletal problems, non-musculoskeletal problems, and PA. Anthropometric data were gathered on all 115 subjects. Results show that there are differences in both pain and PA across instrument groups. Violinists reported the highest number of pain sites, followed by violists, bassists, and cellists. The left shoulder was the most-often reported pain site, followed by the neck and right shoulder. Aching was the most cited term selected to describe pain. Several anthropometric indices were significantly correlated with pain, notably right thumb to index finger span in both cellists and bassists. In all instrument groups, at least one pain site was significantly correlated with one of four PA questions. Results warrant the development of intervention strategies and further study of the relationship between pain and performance anxiety.
Date: May 2011
Creator: Meidell, Katrin Liza
System: The UNT Digital Library
Evaluating and Blending Multimedia Mobile Applications into Technical Training (open access)

Evaluating and Blending Multimedia Mobile Applications into Technical Training

This study in the aerospace ground equipment (AGE) apprentice course at Sheppard Air Force Base, Texas, examined the use of mobile digital devices to determine which device leveraged the best results and was most compatible with military technical training requirements. The sample consisted of 160 students who attended the course between January and June, 2010. Three devices loaded with course materials were issued to the students, who used the devices in the classroom and were encouraged to use the devices to enhance their study time after class. Quantitative data were obtained by comparing block test scores to determine if any device produced a significant change in student learning. Qualitative data were collected from surveys administered to instructors and students to measure which device instructors and students found easiest to understand and use, and student satisfaction with the device. An analysis of variance (ANOVA) revealed a statistically significant difference (p < .05) in the block test mean scores between groups using mobile devices and the students in the control group that had no device. Post hoc comparisons on each block showed that there was a statistically significant difference between students using the smartphone and students using the other devices, but no …
Date: May 2011
Creator: Moore, Billy R.
System: The UNT Digital Library
Elementary Math Achievement in Texas: What is Working? (open access)

Elementary Math Achievement in Texas: What is Working?

Elementary math teachers (76) from selected Texas schools that included Grade 5 responded to an online self-report survey with respect to school-level factors that may be associated with student math achievement. Questions on the survey focused on school-level factors related to math, campus leadership, integration of technology in the math classroom, teacher expectations, utilization of student data in decision-making and professional development. The schools included in the study were rated as Acceptable or Exemplary schools by the Texas Education Agency for three-consecutive years (2007-2010). Logistic regression techniques were used to analyze the data and 11 questions out of 45 were analyzed to determine the odds ratio. Factors that were correlated with being an Exemplary campus were teacher certification routes, not benchmarking student progress, implementation of response to intervention (RTI), classroom management focus (equally divided between student and teacher centered) within the classroom, and technology integration. The results indicated that at the .05 level of probability, the only factor that met that level of significance was full implementation of RTI.
Date: May 2011
Creator: Moore, Linda H.
System: The UNT Digital Library
Gibbs/Equilibrium Measures for Functions of Multidimensional Shifts with Countable Alphabets (open access)

Gibbs/Equilibrium Measures for Functions of Multidimensional Shifts with Countable Alphabets

Consider a multidimensional shift space with a countably infinite alphabet, which serves in mathematical physics as a classical lattice gas or lattice spin system. A new definition of a Gibbs measure is introduced for suitable real-valued functions of the configuration space, which play the physical role of specific internal energy. The variational principle is proved for a large class of functions, and then a more restrictive modulus of continuity condition is provided that guarantees a function's Gibbs measures to be a nonempty, weakly compact, convex set of measures that coincides with the set of measures obeying a form of the DLR equations (which has been adapted so as to be stated entirely in terms of specific internal energy instead of the Hamiltonians for an interaction potential). The variational equilibrium measures for a such a function are then characterized as the shift invariant Gibbs measures of finite entropy, and a condition is provided to determine if a function's Gibbs measures have infinite entropy or not. Moreover the spatially averaged limiting Gibbs measures, i.e. constructive equilibria, are shown to exist and their weakly closed convex hull is shown to coincide with the set of true variational equilibrium measures. It follows that the …
Date: May 2011
Creator: Muir, Stephen R.
System: The UNT Digital Library
Phase Separation and Second Phase Precipitation in Beta Titanium Alloys (open access)

Phase Separation and Second Phase Precipitation in Beta Titanium Alloys

The current understanding of the atomic scale phenomenon associated with the influence of beta phase instabilities on the evolution of microstructure in titanium alloys is limited due to their complex nature. Such beta phase instabilities include phase separation and precipitation of nano-scale omega and alpha phases in the beta matrix. The initial part of the present study focuses on omega precipitation within the beta matrix of model binary titanium molybdenum (Ti-Mo) alloys. Direct atomic scale observation of pre-transition omega-like embryos in quenched alloys, using aberration-corrected high resolution scanning transmission electron microscopy and atom probe tomography (APT) was compared and contrasted with the results of first principles computations performed using the Vienna ab initio simulation package (VASP) to present a novel mechanism of these special class of phase transformation. Thereafter the beta phase separation and subsequent alpha phase nucleation in a Ti-Mo-Al ternary alloy was investigated by coupling in-situ high energy synchrotron x-ray diffraction with ex-situ characterization studies performed using aberration corrected transmission electron microscopy and APT to develop a deeper understanding of the mechanism of transformation. Subsequently the formation of the omega phase in the presence of simultaneous development of compositional phase separation within the beta matrix phase of a …
Date: May 2011
Creator: Devaraj, Arun
System: The UNT Digital Library
Modeling Student Perception of Web 2.0 Technologies Adoption in Kuwait (open access)

Modeling Student Perception of Web 2.0 Technologies Adoption in Kuwait

The primary focus of this dissertation was to explore students' perceptions of adopting Web 2.0 applications at the School of Basic Education (SBE) in Kuwait. Although Web 2.0 applications are becoming more popular among the digital generation, there is still no evidence of students' perceptions of adopting the innovation of Web 2.0 technologies in Kuwait. The problem this study addresses is that the current status of Web 2.0 technologies usage by academic students has remained educationally unknown in Kuwait. Therefore, there was a need to investigate the extent to which academic students in SBE are aware of and their usage of Web 2.0 technologies, as well as the factors and obstacles that affect using these technologies. Rogers' diffusion of innovation theory (DoI) is employed in this study to specify the factors that influence student perceptions of adopting Web 2.0 applications as learning tools. Data used in this dissertation was gathered via a survey instrument from 350 students at the SBE and was statistically analyzed to find out the answers of the research questions. This study identified the low rate of Web 2.0 awareness and adoption by the students. Descriptive statistical analysis, such as mean scores and standard deviation, were used …
Date: May 2011
Creator: Alajmi, Mohammad
System: The UNT Digital Library
The Impact of Training on Employee Advancement (open access)

The Impact of Training on Employee Advancement

In recent years, organizations have invested increasing financial and labor-related resources on employee training. The assumption is that training will benefit the organization through improved performance which will result in greater efficiency, greater customer satisfaction and, ultimately, increased revenue and profits. Further, employees are assumed to benefit because their improved performance should lead to career advancement and increased compensation. However, measuring the effect of training on employee performance has been problematic due to the difficulty of isolating the effect of training from other human resource management practices and environmental and organizational influences. Hierarchical multiple regression analyses were used to test a model for predicting merit pay increase, job promotion and performance ratings from measures of general and finance training, as well as employee tenure, gender, educational level and organizational level. It was found that while significant contributions (i.e., betas) were made by finance and general training for performance ratings, promotion and merit pay increase, they did not increase the variance accounted for by tenure, organizational level and gender.
Date: May 2011
Creator: Bradley, Lori
System: The UNT Digital Library