UNT Theses and Dissertations - 420 Matching Results

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"The Long Goodbye": Uncertainty Management in Alzheimer's Caregivers

Description: Caregivers for individuals diagnosed with Alzheimer's disease (AD) shoulder a remarkably complex burden as compared to other caregivers of elderly individuals. For long distance caregivers, geographical separation further compounds the problems experienced by AD caregivers, as they are isolated from family members and support networks. Both on-site and long-distance AD caregivers experience uncertainty; the findings from this study illustrate how AD caregivers manage the uncertainty of the disease and primary care, as well as how uncertainty differs between on-site and long-distance caregivers. AD caregiver (N = 13) interviews were transcribed and qualitatively analyzed using uncertainty management theory as a thematic lens. The analysis revealed that AD caregivers experience overwhelming feelings of burden, guilt, and doubt; however, these feelings manifest differently depending on caregiver type. The findings of this study demonstrate that sources for obtaining information regarding AD and caregiving were useful for on-site caregivers; however, the sources did not account for the needs of long-distance caregivers or the psychosocial needs of on-site caregivers. Furthermore, AD caregivers did not seek support or information about AD and caregiving from health care professionals. Implications for future research regarding long-distance and on-site AD caregiving are discussed.
Date: May 2011
Creator: Shaunfield, Sara
Partner: UNT Libraries

Portrait of a southern Progressive: The political life and times of Governor Pat M. Neff of Texas, 1871-1952

Description: Pat M. Neff was a product of his political place and time. Born in Texas in 1871, during Reconstruction, he matured and prospered while his native state did the same as it transitioned from Old South to New South. Neff spent most of his life in Waco, a town that combined New South Progressivism with religious conservatism. This duality was reflected in Neff's own personality. On moral or religious issues, he was conservative. On economic and social issues, he was Progressive. He thus was a typical Southern Progressive who de-emphasized social and political change in favor of economic development. For instance, as governor from 1921 to 1925, his work to develop and conserve Texas' water resources brought urbanization and industrialization that made the New South a reality in the state. Neff was a devout Baptist which influenced his politics and philosophy. He was president of Baylor University, a Baptist institution, for fifteen years after leaving the governor s office and he led the Southern Baptist Convention (SBC) in the 1940s. He combined Progressive and Christian values as he argued for the establishment of the United Nations and advocated forgiveness and brotherhood after World War II. The war's end marked the beginning of the American civil rights movement. Many within the SBC advocated an end to racism and discrimination, others did not. Neff's unwillingness to challenge racial traditions was typical of southern Progressives. The convergence of national politics and southern evangelical religion is evident in the final chapter of Neff's career. His selection of President Harry S. Truman as the recipient of an honorary doctorate from Baylor offended many religious conservatives. Neff overcame the opposition but it damaged his reputation and ultimately forced his resignation, ending his public career. By the time of his death in 1952, Texas had become everything ...
Date: May 2011
Creator: Stanley, Mark
Partner: UNT Libraries

Jacques-Antoine-Hippolyte, comte de Guibert: Father of the Grande Armée

Description: The eighteenth century was a time of intense upheaval in France. The death of Louis XIV in 1715 and the subsequent reign of Louis XV saw the end of French political and martial hegemony on the continent. While French culture and language remained dominant in Europe, Louis XV's disinterested rule and military stagnation led to the disastrous defeat of the French army at the hands of Frederick the Great of Prussia in the Seven Years War (1756-1763). The battle of Rossbach marked the nadir of the French army in the Seven Years War. Frederick's army routed the French infantry that had bumbled its way into massed Prussian cavalry. Following the war, two reformist elements emerged in the army. Reformers within the government, chiefly Etienne François, duc de Choiseul, sought to rectify the army's poor performance and reconstitute France's military establishment. Outside the traditional army structure, military thinkers looked to military theory to reinvigorate the army from within and without. Foremost among the latter was a young officer named Jacques-Antoine-Hippolyte de Guibert, whose 1772 Essai général de tactique quickly became the most celebrated work of theory in European military circles. The Essai provided a new military constitution for France, proposing wholesale reform to create an army that could face the Prussian juggernaut. His star quickly rising, Guibert became the toast not only of literary Paris but all of Europe. Guibert exerted an overwhelming influence on military theory across Europe for the next fifty years. His military theories laid the foundation for the French army of the Revolutionary and Napoleonic eras. As other nations adopted French methods, Guibert's influence spread across the continent, reigning supreme until the 1830s. Guibert's importance to military theory is analogous to Voltaire's influence on European literature and culture, an area in which Guibert was not unfamiliar. Guibert ...
Date: May 2011
Creator: Abel, Jonathan, 1985-
Partner: UNT Libraries

Faculty Research Productivity at Addis Ababa University

Description: This study explores the research productivity of Addis Ababa University (AAU) faculty. AAU was established in 1950 and is the oldest modern higher educational institution in Ethiopia. Recently AAU took steps to transform itself to become a pre-eminent African research university. One of the characteristics of a research university is the focus on the amount of research conducted by the institution's faculty. Academic institutions measure research productivity primarily based on published work. The purpose of this study was to analyze the research productivity of AAU faculty, and to examine the differential predictive effects of individual and environmental variables on faculty research productivity. This quantitative study used a theoretical framework and instrument, Faculty at Work. Four hundred questionnaires were distributed to Addis AAU faculty in person and 298 questionnaires were returned resulting in a 74.5% response rate. After exclusion of 12 cases with missing information, 286 cases (71.5% response rate) were analyzed. Most of the respondents were men (M = 92.1%, F = 7.9%). The average age of AAU faculty was 44. A hierarchical multiple regression was used to examine the ability of six sets of independent variables (sociodemographic, career, self-knowledge, social knowledge, behavior, and environmental response) to predict research productivity (publication output). Results indicated that there are productive researchers at AAU, and the theoretical framework explained 67.6% of the variance in publication output.
Date: May 2011
Creator: Stafford, Mehary T.
Partner: UNT Libraries

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

Description: 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 of the federal judiciary as it relates to the continued validity of Lemon and theorizes how the future course of any Establishment Clause legal challenges may ultimately be resolved by the federal courts. The analysis suggested that, while the Supreme Court has avoided Lemon's three-part test as the standard for evaluating Establishment Clause claims, the lower courts continue to place a strong emphasis on the importance of the test established in Lemon as the basis for how they render their decisions with issues that involve public education. This data indicated that Lemon continues to be an important tool for determining ...
Date: May 2011
Creator: Sanders, Russell Scott
Partner: UNT Libraries

The Significance of Feudal Law in Thirteenth-Century Law Codes

Description: Although developments in feudal law in the thirteenth century influenced the legal environment of Europe for centuries, much of past and current historical research of feudalism examines the social system anthropologically but neglects an in-depth analysis of feudal law codes. My research combines the social-anthropological approach with relevant customary codes to demonstrate the importance of feudal law to a thirteenth-century society plagued by war, economic and social instability, and competing powers of the monarchy, judiciary, and religion. The assessment of feudal law within each legal code highlights its prominence as an accepted category of jurisprudence. This thesis provides a new perspective on the influence of feudalism in the thirteenth century, demonstrating the significance of feudal law as a mode of maintaining peace and prolonging land tenure.
Date: May 2011
Creator: Sijansky, Adam Wayne
Partner: UNT Libraries

Mechanisms of Ordered Gamma Prime Precipitation in Nickel Base Superalloys

Description: Commercial superalloys like Rene88DT are used in high temperature applications like turbine disk in aircraft jet engines due to their excellent high temperature properties, including strength, ductility, improved fracture toughness, fatigue resistance, enhanced creep and oxidation resistance. Typically this alloy's microstructure has L12-ordered precipitates dispersed in disordered face-centered cubic γ matrix. A typical industrially relevant heat-treatment often leads to the formation of multiple size ranges of γ¢ precipitates presumably arising from multiple nucleation bursts during the continuous cooling process. The morphology and distribution of these γ′ precipitates inside γ matrix influences the mechanical properties of these materials. Therefore, the study of thermodynamic and kinetic factors influencing the evolution of these precipitates and subsequent effects is both relevant for commercial applications as well as for a fundamental understanding of the underlying phase transformations. The present research is primarily focused on understanding the mechanism of formation of different generations of γ′ precipitates during continuous cooling by coupling scanning electron microscopy (SEM), energy filtered TEM and atom probe tomography (APT). In addition, the phase transformations leading to nucleation of γ′ phase has been a topic of controversy for decades. The present work, for the first time, gives a novel insight into the mechanism of order-disorder transformations and associated phase separation processes at atomistic length scales, by coupling high angle annular dark field (HAADF) - STEM imaging and APT. The results indicate that multiple competing mechanisms can operate during a single continuous cooling process leading to different generations of γ′ including a non-classical mechanism, operative at large undercoolings.
Date: May 2011
Creator: Singh, Antariksh Rao Pratap
Partner: UNT Libraries

The Relationship Between Supplemental Instruction Leader Learning Style and Study Session Design

Description: The purpose of this qualitative study was to examine the learning styles of supplemental instruction leaders at a large, public university during the fall 2010 semester and determine whether or not their personal learning styles influenced the way they designed and developed out-of-class study sessions. The total population of supplemental instruction leaders was 37, of which 24 were eligible to participate in the study. Of the 24 eligible supplemental instruction leaders, 20 completed the entire study. Participants in the study included nine male and 11 female supplemental instruction leaders with a median age of 22.25 years-old. Seventeen participants indicated their classification as senior, two as junior, and one as sophomore. Of the participants, 16 indicated white as a race or ethnicity, one indicated Asian, two indicated African American, and one indicated both American Indian/Alaska Native and white. Supplemental instruction leader learning style was assessed using the Kolb Learning Style Inventory. Leaders were then interviewed, and their study sessions were analyzed. Through triangulation of data from learning style, interviews and actual study session documents, four major themes emerged. The four themes were: 1) incorporation of personal experience into study session design, 2) the sense of impact on student learning, 3) a feeling of the need to incorporate varied activities into study session design, and 4) the concept that students must take ownership over their own learning. No consistent pattern emerged among the themes; however, the results attributed out-of-class study session design to both the incorporation of personal learning style preferences as identified through the Kolb Learning Style Inventory and training conducted by the institution. Implications for future research include the need for continued research addressing how and if supplemental instruction leader learning style influences out-of-class study session design. Also, as institutions of higher education seek to expand academic support services to ...
Date: May 2011
Creator: Adams, Joshua
Partner: UNT Libraries

Solvent Effects and Bioconcentration Patterns of Antimicrobial Compounds in Wetland Plants

Description: This study looked at effects of organic solvents dimethylsulfoxide, dimethylformamide and acetone at 0.01%, 0.05% and 0.1% concentration on germination and seedling development wetland plants. Even at 0.01% level, all solvents affected some aspect of seed germination or seedling growth. Acetone at 0.01% was least toxic. Root morphological characteristics were most sensitive compared to shoot morphological characteristics. This study also looked at bioconcentration patterns of antimicrobial compounds triclosan, triclocarban and methyl-triclosan in wetland plants exposed to Denton Municipal Waste Water Treatment Plant effluent. Bioconcentration patterns of antimicrobial compounds varied among species within groups as well as within organs of species. The highest triclocarban, triclosan and methyltriclosan concentration were in shoot of N. guadalupensis, root of N. lutea and in shoots of P. nodous respectively.
Date: May 2011
Creator: Adhikari, Sajag
Partner: UNT Libraries

Consensus Building in Sensor Networks and Long Term Planning for the National Airspace System

Description: In this thesis, I present my study on the impact of multi-group network structure on the performance of consensus building strategies, and the preliminary mathematical formulation of the problem on improving the performance of the National Airspace system (NAS) through long-term investment. The first part of the thesis is concerned with a structural approach to the consensus building problem in multi-group distributed sensor networks (DSNs) that can be represented by bipartite graph. Direct inference of the convergence behavior of consensus strategies from multi-group DSN structure is one of the contributions of this thesis. The insights gained from the analysis facilitate the design and development of DSNs that meet specific performance criteria. The other part of the thesis is concerned with long-term planning and development of the NAS at a network level, by formulating the planning problem as a resource allocation problem for a flow network. The network-level model viewpoint on NAS planning and development will give insight to the structure of future NAS and will allow evaluation of various paradigms for the planning problem.
Date: May 2011
Creator: Akula, Naga Venkata Swathik
Partner: UNT Libraries

Mosques in France: The Visible Presence of Islam

Description: Numerous laws are being directed toward subduing the visible presence of Islam throughout France, and in return French Muslims are becoming bolder in the projection of their faith. This thesis examines the presence of Islam in France throughout history and in contemporary French civilization. Specifically, this thesis addresses the issues regarding the visible presence of Islam in France through such institutions as mosques and how they are the key symbols representing the prominence of Islam in France. It looks at what lies in the collective French mind that creates such an influence on today's policies and outlook, as well as identifies the key characters that dominate the current affairs surrounding Islam in France. The thesis reviews the country's past relations with the visible presence of Islam through the controversies surrounding the construction of famous mosques. In addition, this thesis underlines key areas where both the State and the Muslim population must make concessions in order to avoid further conflict.
Date: May 2011
Creator: Arnold, Ashley Patricia
Partner: UNT Libraries

Miscegenated Narration: The Effects of Interracialism in Women's Popular Sentimental Romances from the Civil War Years

Description: Critical work on popular American women's fiction still has not reckoned adequately with the themes of interracialism present in these novels and with interracialism's bearing on the sentimental. This thesis considers an often overlooked body of women's popular sentimental fiction, published from 1860-1865, which is interested in themes of interracial romance or reproduction, in order to provide a fuller picture of the impact that the intersection of interracialism and sentimentalism has had on American identity. By examining the literary strategy of "miscegenated narration," or the heteroglossic cacophony of narrative voices and ideological viewpoints that interracialism produces in a narrative, I argue that the hegemonic ideologies of the sentimental romance are both "deterritorialized" and "reterritorialized," a conflicted impulse that characterizes both nineteenth-century sentimental, interracial romances and the broader project of critiquing the dominant national narrative that these novels undertake.
Date: May 2011
Creator: Beeler, Connie
Partner: UNT Libraries

Sheltered Instruction: A Case Study of Three High School English Teachers' Experiences with the SIOP Model

Description: The purpose of this study was to determine the current status of secondary teachers' implementation of the sheltered instruction operational protocol (SIOP) model and its effect on Hispanic English language learners' (ELL) English language proficiency and academic achievement. In addition, this study sought to determine whether teachers perceive the SIOP model as an effective tool for instruction of high school ELL students to increase English language content and English language proficiency. This study employed qualitative and quantitative methodologies. Data were collected from four sources: Hispanic ELLs' English language proficiency scores, students' English Language Arts scores, an oral interview with participating teachers and teacher observations. Each teacher was observed at four points during the school year with the SIOP instrument. Quantitative data on student achievement were collected employing a pre-experimental, one-group pretest-post-test design. Qualitative data were collected using a time-series design. Findings revealed that on the two student assessment measures there were increases in English proficiency and English language arts achievement among the Hispanic ELLs. On the assessment of English language proficiency, the students of the teacher with the highest level of SIOP implementation made the highest gains; the students of the teacher with the second highest SIOP implementation level made the second highest gains; and students of the teacher with the lowest level of SIOP implementation made the smallest gains. These findings suggest that the higher the level of SIOP implementation, the greater the student academic achievement gains. The gains in academic achievement attributed to the proper implementation of the SIOP model can have an extensive impact on English language learners who have not previously experienced academic success. Teacher participants perceived the SIOP model as effective for delivery of content through sheltered instruction lessons for high school ELLs. The teachers agreed that the SIOP model's components provided a consistent structure ...
Date: May 2011
Creator: Bertram, Rodney L.
Partner: UNT Libraries

Recommended Modified zone Method Correction Factor for Determining R-values of Cold-Formed Steel Wall Assemblies

Description: Currently, ASHRAE has determined the zone method and modified zone method are appropriate calculation methods for materials with a high difference in conductivity, such as cold-formed steel (CFS) walls. Because there is currently no standard U-Factor calculation method for CFS walls, designers and code officials alike tend to resort to the zone method. However, the zone method is restricted to larger span assemblies because the zone factor coefficient is 2.0. This tends to overestimate the amount of surface area influenced by CFS. The modified zone method is restricted to C-shaped stud, clear wall assemblies with framing factors between 9 and 15%. The objective of the research is to narrow the gap of knowledge by re-examining the modified zone method in order to more accurately determine R-Values and U-Factors for CFS wall assemblies with whole wall framing factor percentages of 22% and above.
Date: May 2011
Creator: Black, John
Partner: UNT Libraries

Spatial Ability, Motivation, and Attitude of Students as Related to Science Achievement

Description: Understanding student achievement in science is important as there is an increasing reliance of the U.S. economy on math, science, and technology-related fields despite the declining number of youth seeking college degrees and careers in math and science. A series of structural equation models were tested using the scores from a statewide science exam for 276 students from a suburban north Texas public school district at the end of their 5th grade year and the latent variables of spatial ability, motivation to learn science and science-related attitude. Spatial ability was tested as a mediating variable on motivation and attitude; however, while spatial ability had statistically significant regression coefficients with motivation and attitude, spatial ability was found to be the sole statistically significant predictor of science achievement for these students explaining 23.1% of the variance in science scores.
Date: May 2011
Creator: Bolen, Judy Ann
Partner: UNT Libraries

Modeling Student Perception of Web 2.0 Technologies Adoption in Kuwait

Description: 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 to analyze and conclude the findings. In the rates of awareness and adoption of Web 2.0, this study also identified no statistically significant differences between the groups of all the demographic variables except the academic field. The statistically significant differences were identified between the academic variables before and after recoding the academic fields into 5 groups. A t-test and one-way ANOVA were used to determine the statistical significance. Several factors were examined in the study to identify their influence on the rate of adoption. The factors included the rate of awareness, Rogers' attributes of innovations, and the obstacles to adopt ...
Date: May 2011
Creator: Alajmi, Mohammad
Partner: UNT Libraries

Retinoic acid Treatment Affects Kidney Development and Osmoregulatory System in the Developing Chicken (Gallus Gallus)

Description: Development is a dynamic process characterized by critical periods in which organ systems are sensitive to changes in the surrounding environment. In the current study, critical windows of embryonic growth and kidney development were assessed in the embryonic chicken. All‐trans retinoic acid (tRA) influences not only organogenesis and cell proliferation, but also targets metanephric kidney nephrogenesis. Embryonic chickens were given a single injection of tRA on embryonic day 8. tRA decreased embryo, kidney, and heart mass from day 16 to day 18. However, mass specific kidney and heart masses showed no differences. Whole blood, plasma, and allantoic fluid osmolality were altered in tRA treated embryos from day 16 to day 18. In addition, hematocrit, red blood cell count, and hemoglobin concentration were altered in tRA treated embryos. The results suggest that although nephrogenesis was not affected by tRA, the developing osmoregulatory system was altered in tRA treated embryos.
Date: May 2011
Creator: Alvine, Travis Douglas
Partner: UNT Libraries

The Impact of Training on Employee Advancement

Description: 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
Partner: UNT Libraries

Mechanisms Affecting Bench Press Throw Performance while Using a Counter-Balanced Smith Machine

Description: The use of a counter-balance weight system of a Smith machine affects measures of bench press throw performance. Twenty-four men performed bench press throws at 30% of their one-repetition maximum under four different conditions: 1) counter-balance and rebound movement (RC), 2) no counter-balance and rebound movement (RNC), 3) counter-balance and concentric only movement (CC), and 4) no counter-balance and concentric only movement (CNC). Peak power, force, and concentric and eccentric velocities were measured using a linear accelerometer; and peak ground reaction force (GRF) was measured using a forceplate. Peak measures for concentric and eccentric velocities showed that NCB> CB and RBT > CBT. Peak GRF measures showed CB > NCB and RBT > CBT. The lower performance measures for CB were likely due to an increase in the net external load when the barbell accelerates faster than the gravitational constant causing the counter-balance weight becomes ineffective.
Date: May 2011
Creator: Buddhadev, Harsh
Partner: UNT Libraries

Re-Branding Palliative Care: Assessing Effects of a Name Change on Physician Communicative Processes During Referrals

Description: Although provision of palliative care on the United States is growing, referrals to the service are often late or non-existent. The simultaneous care model provides a blueprint for the most progressive form of palliative care, which is palliation and disease-oriented treatments delivered concurrently. Research indicates the existence of a widespread misconception that associates palliative care with imminent death, and some organizations have chosen to re-brand their palliative care services to influence this perception. The goal of this study was to assess the effects of a name change from palliative care to supportive care on the communicative process during referrals to the service.
Date: May 2011
Creator: Burt, Stephanie
Partner: UNT Libraries

El ékfrasis en la Poesía De Manual Machado

Description: Manuel Machado is known as one of the most innovative Spanish modernist poets of the twentieth century. Despite his recognition as a literary figure in Spain, the mimetic descriptions in Machado's poetics are interpreted as mere innovations in Spanish poetry. Those mimetic descriptions are examples of ekphrasis in Spanish literature. Ekphrasis is both a literary and representational art. The mimetic dimension in Machado's poetry is ignored or misinterpreted by the critics of his poetics. This study written in Spanish investigates the use of ekphrasis in terms of Machado's poetic style. An analysis of Manuel Machado's ekphrastic poems will determine: ekphrastic poetry is a representational art; how visual and acoustic aspects of Machado's poems create enargeia; and the manifestation of ekphrasis in Spanish verse. In using Machado's poems, this project will contribute to future explorations of ekphrasis in Spanish literature.
Date: May 2011
Creator: Carrillo, Yolanda
Partner: UNT Libraries

Parent-Toddler Training: The Merits of Further Analysis

Description: Earlier identification of autism allows for interventions to begin during toddlerhood. Literature suggests that parents are an important part of very early intervention and specific goals have indicated that they are important to progress. The use of telemedicine may increase access to interventions. The purpose of the study was to evaluate a parent-toddler training program that targeted social-communication skills and incorporated a telemedicine component. Measures included parent teaching targets, child attending, vocal requesting, and coordinated joint attention and the parent's response to coordinated joint attention. Results indicate that parent teaching increased, child attending and vocalizations increased, child coordinated joint attention increased, and the parent's response to coordinated joint attention was primarily social in nature. Analysis of the home observations indicates that direct in home observations or teleconference observations neither under or overestimated behaviors. The results are discussed in the context of teaching and feedback delivery and selection of teaching targets.
Date: May 2011
Creator: Cermak, Samantha Marie
Partner: UNT Libraries

Examining Curvilinearity and Moderation in the Relationship between the Degree of Relatedness of Individual Diversification Actions and Firm Performance

Description: Corporate diversification continues to be an important phenomenon in the modern business world. More than thirty years of research on diversification suggests that the degree of relatedness among a firm's business units is a factor that can affect firm performance, but the true effect of diversification relatedness on firm performance is still inconclusive. The purpose of this dissertation is to shed more light on this inconclusive association. However, attention is focused on the performance implications of individual diversification actions (e.g., acquisitions and joint ventures) rather than on the overall performance of firms with different levels of diversification. A non-experimental, longitudinal analysis of secondary data was conducted on over 450 unique acquisitions and on more than 210 joint ventures. Results suggest that even when individual diversification actions rather than entire business portfolios are examined, an inverted curvilinear association between diversification relatedness and performance is likely to emerge. This pattern is observed in both acquisitions and joint ventures. However, the association between diversification relatedness and performance in acquisitions is moderated by the level of industry adversity, though factors such as corporate coherence and heterogeneous experience do not moderate the association between diversification relatedness and performance. This study augments the body of knowledge on diversification and adds refinement to the traditional curvilinear finding regarding relatedness. By studying acquisitions and joint ventures independently, the results reveal differences in both slope and inflection points that suggest the relative impact of relatedness may vary depending on the mode of diversification.
Date: May 2011
Creator: Cernas Ortiz, Daniel Arturo
Partner: UNT Libraries

Phase Separation and Second Phase Precipitation in Beta Titanium Alloys

Description: 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 Ti-10V-6Cu (wt%) alloy during continuous cooling has been investigated using a combination of transmission electron microscopy and atom probe tomography. The results of these investigations provided novel insights into the mechanisms of solid-state transformations in metallic systems by capturing the earliest stages of nucleation at atomic to near atomic spatial and compositional resolution.
Date: May 2011
Creator: Devaraj, Arun
Partner: UNT Libraries