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An Examination of Maternal Acceptance among Mothers and their Children with ADHD Symptomatology
The current study examined the role of self-reported and child-reported maternal lack of acceptance in increasing the likelihood of developing internalizing and externalizing symptoms among children with ADHD symptomatology. The effects of a social desirability bias on mother’s self-reports of rejection were controlled for. Mother-child agreement about parenting behaviors like warmth/affection, hostility/aggression and indifference/neglect was also investigated. In addition, variables with the potential to affect agreement (i.e., parents’ social desirability bias, child age, child sex) were examined. Participants included 120 boys and 90 girls, 6 to 11 years old (M = 8.25, SD = 1.18) with and without ADHD and their primary parent/guardian (N = 209). Parent and child participants completed self-report instruments separately. Results indicate that the relationship between mother-and-child-reported ADHD symptoms and internalizing symptoms is strongest when mothers exhibit low levels of rejection. Among the ADHD subsample, maternal lack of acceptance acts as a risk factor by strengthening the relationship between hyperactive/impulsive symptoms and externalizing symptoms. In addition, mothers and their children report significantly different levels of parenting behaviors. Child age and child sex were significant predictors of parent-child disagreement. digital.library.unt.edu/ark:/67531/metadc84248/
Type D Personality and Coping Style as Predictors of Cardiovascular Risk
Although cardiovascular disease (CVD) does not occur until mid to late life for most adults, the presence of risk factors for CVD, such as high blood pressure (BP) and high cholesterol, has increased dramatically in young adults. Type D personality consists of two personality traits, negative affectivity (NA) and social inhibition (SI), and has repeatedly been shown to be an independent predictor of hard medical outcomes (e.g. morbidity and mortality) in cardiac patients. The present study examined the relationships between Type D personality (high NA and high SI), coping strategies, and physiological markers of cardiovascular health in a sample of non-medical, university students. Measures of cardiovascular risk included high frequency heart rate variability (HF HRV), calculated LDL cholesterol, and systolic blood pressure (SBP). Regression analyses revealed that higher use of social supportive coping was a significant predictor of calculated LDL cholesterol. Social supportive coping was also shown to moderate the relationship between Type D personality and HF HRV. Interventions that target psychological and physiological mechanisms associated with CVD are well developed. Clear identification of young adults who are at risk of developing CVD is necessary to intervene in a manner that could potentially save lives. Additional systematic research, especially if it is longitudinal, will help to clarify the ability of Type D personality and coping to predict CVD. digital.library.unt.edu/ark:/67531/metadc84244/
Beyond the Cabinet: Zbigniew Brzezinski’s Expansion of the National Security Adviser Position
The argument illustrated in the thesis outlines Zbigniew Brzezinski’s ability to manipulate himself and his agenda to top priority as the national security advisor to President Carter. It further argues that Brzezinski deserves more blame for the failure of American foreign policy towards Iran; not President Carter. The sources include primary sources such as Zbigniew Brzezinski and President Jimmy Carter’s memoirs as well as information from President Carter’s library in Atlanta, Georgia. Secondary sources include historians who focus on both presidential policy and President Carter and his staff. The thesis is organized as follows: the introduction of Brzezinski, then the focus turns to his time in the White House, Iran, then what he is doing today. digital.library.unt.edu/ark:/67531/metadc84249/
An Essential Academic Program: A Case Study of the General Studies Program at Louisiana State University in Shreveport
The purpose of this study was to provide a historical overview of the development of the General Studies (GS) program at LSU Shreveport from its inception in 1967 until 2007. Sources of data were primary, secondary, and archival documents, student information accessed through the university mainframe, alumni information obtained from a university-sponsored directory, and an interview with the former vice-chancellor of academic affairs. All data were analyzed and placed in a chronological framework. The resulting framework consisted of dividing the 40 years of program existence into four ten-year periods. The study was limited in scope to the GS program at LSU Shreveport and did not seek to compare this program with other programs offered at the university or other GS programs in the state. The study results identified several key social, economic, and political factors that influenced the program’s development. Political factors included the change from a two-year to a four-year institution, the Statewide Review Committee recommendations of 1983, the dissolving of the College of General Studies in 1984, and the accountability movement of the 1990s. Key social factors discovered were the Civil Rights and Women’s Movements of the 1960s,and progressive, life adjustment, and humanistic educational philosophies. Economic factors revealed were the economic recessions of the 1970s and 2007, the technology burst of the 90s,and the current War on Terror. The study also revealed that the GS program has fulfilled the directives of the 1983 Statewide Review Committee Recommendations. Recommendations for future development of the program include adding an online option and implementing an exit survey. digital.library.unt.edu/ark:/67531/metadc84246/
Biocompatible Hybrid Nanomaterials Involving Polymers and Hydrogels Interfaced with Phosphorescent Complexes and Toxin-Free Metallic Nanoparticles for Biomedical Applications
The major topics discussed are all relevant to interfacing brightly phosphorescent and non-luminescent coinage metal complexes of [Ag(I) and Au(I)] with biopolymers and thermoresponsive gels for making hybrid nanomaterials with an explanation on syntheses, characterization and their significance in biomedical fields. Experimental results and ongoing work on determining outreaching consequences of these hybrid nanomaterials for various biomedical applications like cancer therapy, bio-imaging and antibacterial abilities are described. In vitro and in vivo studies have been performed on majority of the discussed hybrid nanomaterials and determined that the cytotoxicity or antibacterial activity are comparatively superior when compared to analogues in literature. Consequential differences are noticed in photoluminescence enhancement from hybrid phosphorescent hydrogels, phosphorescent complex ability to physically crosslink, Au(I) sulfides tendency to form NIR (near-infrared) absorbing AuNPs compared to any similar work in literature. Syntheses of these hybrid nanomaterials has been thoroughly investigated and it is determined that either metallic nanoparticles syntheses or syntheses of phosphorescent hydrogels can be carried in single step without involving any hazardous reducing agents or crosslinkers or stabilizers that are commonly employed during multiple step syntheses protocols for syntheses of similar materials in literature. These astounding results that have been discovered within studies of hybrid nanomaterials are an asset to applications ranging from materials development to health science and will have striking effect on environmental and green chemistry approaches. digital.library.unt.edu/ark:/67531/metadc84243/
High Risk Occupations: Employee Stress and Behavior Under Crisis
The purpose of this study is to analyze the relationships between stress and outcomes including organizational citizenship behavior (OCB), job satisfaction, and burnout in high-risk occupations. Moreover, how personality, emotions, coping, and leadership influence this relationship is investigated. Data were collected from 379 officers in 9 police organizations located in the Southern and Southwest United States. The primary research question addressed within this dissertation is: What is the relationship between stress and behavioral and affective outcomes in high-risk occupations as governed by coping, leadership, and crisis? The majority of the hypothesized relationships were supported, and inconsistencies center on methodological and theoretical factors. Findings indicate that occupational stressors negatively influence individuals in high-risk occupations. Moreover, crisis events exacerbate these influences. The use of adaptive coping strategies is most effective under conditions of low stress, but less so under highly stressful circumstances. Similarly, transformational leader behaviors most effectively influence how individuals in high-risk occupations are affected by lower, but not higher levels of stress. Profiles of personality characteristics and levels of emotional dissonance also influence the chosen coping strategies of those working in high-risk occupations. Prescriptively, it is important to understand the influences among the variables assessed in this study, because negative outcomes in high-risk occupations are potentially more harmful to workers and more costly to organizations. Thus, this dissertation answers the research question, but much work in this area remains to be done. digital.library.unt.edu/ark:/67531/metadc84269/
Gentrification in Oklahoma City: Examining Urban Revitalization in Middle America
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Gentrification applies not only to the largest and oldest cities; it is a multi-scalar phenomenon playing out in smaller and less prominent settings as well. This study examines temporal changes in property values, demographic characteristics, and types of businesses in the central Oklahoma City area. A major urban revitalization project which began in 1993 created strong gentrification characteristics near the renewal's epicenter, the Bricktown entertainment district. Data suggest that several specific neighborhoods in the surrounding area exhibited rising property values, improving educational attainment rates, decreasing household sizes, and a shift toward cosmopolitan retail activity. While it is evident that Bricktown has been transformed, the socio-economic traits of surrounding neighborhoods have been altered by the ripple effects of urban renewal. digital.library.unt.edu/ark:/67531/metadc84266/
The Influence of Self-Esteem and Body Dissatisfaction on Muscle Dysmorphia and Exercise Dependence
Using the psycho-behavioral model as a conceptual framework, the purpose of this study was to explore the relationships between self-esteem, body dissatisfaction, muscle dysmorphia, and exercise dependence among college men. Participants (n = 110) completed surveys including a demographic questionnaire, the Rosenberg Self-Esteem Scale, Body Part Satisfaction Scale, Drive for Muscularity Scale, and Exercise Dependence Scale-21. No significant relationship was found between self-esteem and muscle dysmorphia. A significant correlation was found between body dissatisfaction and muscle dysmorphia, as well as between muscle dysmorphia and exercise dependence. These results partially support the psycho-behavioral model of muscle dysmorphia. digital.library.unt.edu/ark:/67531/metadc84263/
The Impact of Leadership Styles and Knowledge Sharing on Police Officers’ Willingness to Exert Extra Effort to Provide Better Security: A Study in the Riot Unit of the Turkish National Police
The motivation for this study is to understand the factors affecting police officers’ willingness to exert extra effort for providing better service through knowledge sharing in different working environments such as riots. Since managers’ leadership styles may be important factors affecting subordinates’ willingness to exert extra effort, this study investigates which of the leadership styles -- transformational, transactional or laissezfaire leadership -- will have a positive effect on officers’ willingness to exert extra effort. In addition, the current study also examines the effect of the mentioned leadership styles on knowledge sharing, which, in turn, affects the officers’ willingness to exert extra effort in the riot unit of the Turkish National Police (TNP) in Ankara, Turkey. The sworn line police officers working in the riot unit in Ankara, Turkey, were the participants in this study. Three questionnaires --a Multifactor Leadership (MLQ), knowledge sharing, and demographic questionnaire -- were arranged as a booklet to be distributed to the respondents. The results of the study indicate that police supervisors' perceived transformational leadership behavior has a positive effect on officers' willingness to exert extra effort. In addition, the findings also reveal that although both officers' years of service in TNP and police supervisors' perceived transactional leadership behavior has no direct effect on officers' willingness to exert extra effort, they have an indirect positive effect through officers' knowledge sharing. On the other hand, police supervisors' perceive that laissez-fair leadership behavior has no effect on riot officers' willingness to exert extra effort. The findings also indicate that officers’ knowledge sharing is positively related to both their supervisors’ perceived transformational and transactional leadership behaviors. However, police supervisors’ perceived laissez-fair leadership behavior has no effect on officers’ knowledge sharing activities. This research study will provide police administrations with the data necessary to adopt the most appropriate leadership styles for increasing police officers' knowledge sharing and extra effort. The findings will also serve as guidance for police managers commanding line police officers working in different environments, such as social movements, demonstrations, and riots. In that they will be aware of how important it is to create a knowledge sharing environment in riot units to provide better security in all legal and illegal demonstrations and riots. Finally, the findings will be a valuable resource not only for Turkish National Police, but also for future research studies and various police organizations in other countries. digital.library.unt.edu/ark:/67531/metadc84290/
Galileo's Eyeglass: An Orchestral Work Celebrating the Discovery of the Moons of Jupiter and the Rings of Saturn
Galileo's Eyeglass is a celebratory work for full orchestra with standard instrumentation commemorating Galileo Galilei's discoveries of the four largest moons of Jupiter and the rings of Saturn in 1610. The composition is approximately 14 minutes in duration, and although divided thematically into four parts, the music is continuous. The work exhibits primarily a blend of contemporary styles and compositional elements, yet it is rooted in traditional tonality; furthermore, the piece is interspersed with references to Galileo's life and times, including quotations of a toccata composed by the scientist's brother, Michelangelo Galilei, transcribed from lute tablature. Chapter 1 of Part 1 investigates relevant historical threads extracted from the backdrop of Galileo's life, from reflections on the events that shape the musical program, to the selection and preparation of the period music composed by Galileo's brother. Chapter 2 discusses specific musical components of Galileo's Eyeglass, including form, musical quotations, motivic and thematic material, harmonic language, orchestration, and notation. Chapter 3 examines the principal philosophical themes behind the composition, including expressions of victory of a life well lived in spite of many obstacles. Part 2 contains the orchestral score. digital.library.unt.edu/ark:/67531/metadc84298/
PTSD Symptoms and Dominant Emotional Response to a Traumatic Event: An Examination of DSM-IV Criterion A2
To qualify for a diagnosis of posttraumatic stress disorder the DSM-IV requires that individuals report dominant emotions of fear, helplessness, and horror during the trauma. Despite this stipulation, traumatic events can elicit a myriad of emotions other than fear such as anger, guilt or shame, sadness, and numbing. The present study examined which emotional reactions to a stressful event in a college student sample are associated with the highest levels of PTSD symptoms. Results suggest mixed support for the DSM-IV criteria. Although participants who experienced a dominant emotion of fear reported high PTSD symptomatology, participants who experienced anger, disgust-related emotions, and sadness reported PTSD symptoms of equivalent severity. Participants also reported experiencing other emotions more frequently than they reported experiencing fear. Coping style was unrelated to dominant emotion experienced; however, dysfunctional coping was associated with worse outcomes in terms of PTSD symptoms. These results have diagnostic and treatment limitations. digital.library.unt.edu/ark:/67531/metadc84294/
True Tales of the Atom
True Tales of the Atom documents the creative process in the making of the film of the same name. It describes the intent and result of each step in the filmmaking process, including esthetic, budget and technical decisions. How the inclusion of animation increased the complexity and technical demands on the postproduction. It shows the problems encountered and overcome working on a production alone. Finally, it details the successful completion primarily due to extensive preplanning. The film on which the paper is based is a non-traditional look at several little-known aspects of civilian nuclear power, with a look at the media that could have helped to shape current attitudes in the United States about the technology. digital.library.unt.edu/ark:/67531/metadc84299/
Evaluating Process Variables in Acceptance and Commitment Therapy
Acceptance and commitment therapy (ACT) was developed to specifically target experiential avoidance (EA) rather than any specific diagnostic category. A functional ACT manual was presented and used to treat diagnostically diverse clients in a large sliding fee-for-service training clinic. A multiple baseline across participants and behaviors research design was used to evaluate session-by-session changes in EA, values identification, valued action, and clinical distress. The Acceptance and Action Questionnaire-2 (AAQ2), Valued Living Questionnaire (VLQ), and Outcome Questionnaire (OQ-45) were given to measure processes and outcomes given the functional ACT model presented in the introduction to the paper. Baseline included the Structured Clinical Interview for DSM-IV Axis I and II Disorders given across 2-5 50- minute sessions. The treatment phase consisted of 7-10 50-minute sessions. Participants were 10 clients. Four participants completed sufficient treatment sessions (4-9) to test the study hypotheses. Participants generally improved across time, but most improvements could not be attributed to the functional application of ACT due to changes during baseline for AAQ, VLQ-Consistency, and OQ-45. VLQ-Importance significantly improved for all participants given ACT. digital.library.unt.edu/ark:/67531/metadc84296/
The Interactions of Plasma with Low-k Dielectrics: Fundamental Damage and Protection Mechanisms
Nanoporous low-k dielectrics are used for integrated circuit interconnects to reduce the propagation delays, and cross talk noise between metal wires as an alternative material for SiO2. These materials, typically organosilicate glass (OSG) films, are exposed to oxygen plasmas during photoresist stripping and related processes which substantially damage the film by abstracting carbon, incorporating O and OH, eventually leading to significantly increased k values. Systematic studies have been performed to understand the oxygen plasma-induced damage mechanisms on different low-k OSG films of various porosity and pore interconnectedness. Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy and atomic force microscopy are used to understand the damage kinetics of O radicals, ultraviolet photons and charged species, and possible ways to control the carbon loss from the film. FTIR results demonstrate that O radical present in the plasma is primarily responsible for carbon abstraction and this is governed by diffusion mechanism involving interconnected film nanopores. The loss of carbon from the film can be controlled by closing the pore interconnections, He plasma pretreatment is an effective way to control the damage at longer exposure by closing the connections between the pores. digital.library.unt.edu/ark:/67531/metadc84175/
Attracted to the Medium: An Analysis of Social Behaviors, Advertising, and Youth Culture in the Emerging Mobile Era
This thesis is a reception study that examines potential reasons why the adolescent to college aged demographic of youth culture is embracing communicative and informational mobility. The project attests that the move to mobility is motivated by two major factors, the attraction of being an early adopter of technology and the way social behaviors are made attractive in mobile marketing. Chapter 1 explores the importance of these social behaviors, as they are very much intertwined and contribute to how youth acclimate into society. Chapter 2 demonstrates that creating social distinction and cultural capital is linked to being an early adopter of technology. The remaining portion of the document examines recent mobile advertisements and why youth would be attracted to the aesthetic and thematic elements contained in the advertisements. Chapter 3 examines how Blackberry utilizes the behavior of creating and expressing identity in their advertisements. Chapter 4 focuses on how Apple has worked to create a community centered around their brand. Finally, Chapter 5 looks at how Google/Android has highlighted the acquisition, sharing, and utilization of content through the phenomenon of applications. With this project, I hope to illustrate the rationale why youth would be attracted to communicative and informational mobility. digital.library.unt.edu/ark:/67531/metadc84172/
Mycielski-Regular Measures
Let μ be a Radon probability measure on M, the d-dimensional Real Euclidean space (where d is a positive integer), and f a measurable function. Let P be the space of sequences whose coordinates are elements in M. Then, for any point x in M, define a function ƒn on M and P that looks at the first n terms of an element of P and evaluates f at the first of those n terms that minimizes the distance to x in M. The measures for which such sequences converge in measure to f for almost every sequence are called Mycielski-regular. We show that the self-similar measure generated by a finite family of contracting similitudes and which up to a constant is the Hausdorff measure in its dimension on an invariant set C is Mycielski-regular. digital.library.unt.edu/ark:/67531/metadc84171/
Religious Coping and Experience of Body Satisfaction Among College Women
This study examined whether religious coping moderated the effects of thin-ideal images on body satisfaction among college women. Religious (N = 178) participants met for a pre-test to complete religiosity measures. A week later, the participants reconvened and were assigned to one of two conditions: before (n = 83) or after (n = 95). Within each of these two groups, participants were randomly assigned to read a list of statements: positive religious statements, positive nonreligious statements, negative religious statements, positive body neutral religious statements, and neutral statements. Each participant was exposed to a task that included 10 images of thin-ideal models, read her list of statements, and completed the Body Dissatisfaction Scale of the EDI-3. The results revealed no significant main effect of placement, type of statement and no significant Placement X Statement Type interaction. However, when religious statements were collapsed and a subsequent 2 (Placement) X 3 (Statement type) analysis was conducted the results indicated a significant main effect for type of statement. Reading religious statements resulted in less body dissatisfaction than non-religious statements. There was no main effect for placement and no Placement X Statement Type interaction. Ethnic differences in religiosity were noted (all p’s <.05). Implications and future directions in research are discussed. digital.library.unt.edu/ark:/67531/metadc84177/
Exposing Deep-rooted Anger: A Metaphor Pattern Analysis of Mixed Anger Metaphors
This project seeks to serve two purposes: first, to investigate various semantic and grammatical aspects of mixed conceptual metaphors in reference to anger; and secondly, to explore the potential of a corpus-based, TARGET DOMAIN-oriented method termed metaphor pattern analysis to the study of mixed metaphor. This research shows that mixed metaphors do not pattern in a manner consistent with statements made within conceptual metaphor theory. These metaphors prove highly dynamic in their combinability and resist resonance between SOURCE DOMAINS used. Also shown is the viability of metaphor pattern analysis as a methodology to approach mixed metaphor research. digital.library.unt.edu/ark:/67531/metadc84170/
Uses and Gratifications of Facebook Members 35 Years and Older
Online social networking sites continue to grow as a medium of consumption, acting as a changing force for interpersonal communication and media interaction. It is important to understand how and why each demographic segment is using these sites. Facebook is the most popular social networking site in the U.S., with older adults representing a substantial portion of the site’s growth. Previous studies have investigated the use of Facebook among college students and young adults; however, older age demographics are a fairly new segment to the online social networking landscape that has not yet been investigated. Through a large-scale online survey, this study represents the first empirical investigation of Facebook members age 35 and older. Findings provide a baseline of knowledge for understanding time spent, frequent activities and gratifications obtained by this audience on Facebook. Results indicate adults 35 and older allocate a substantial amount of time to the site and use it most often for communication with people in their network. While many activities on the site were found to be similar between older and younger audiences, adults 35 and older in this study reported more passive activities of surveillance rather than participation. Factor analysis yielded five gratification factors for Facebook of which three were salient against the 35 and older audience: interpersonal habitual entertainment, passing time and self-expression. Exploratory open-ended questions also revealed some additional unique possible motives to be considered in future research among this audience. digital.library.unt.edu/ark:/67531/metadc84293/
Boron Nitride by Atomic Layer Deposition: A Template for Graphene Growth
The growth of single and multilayer BN films on several substrates was investigated. A typical atomic layer deposition (ALD) process was demonstrated on Si(111) substrate with a growth rate of 1.1 Å/cycle which showed good agreement with the literature value and a near stoichiometric B/N ratio. Boron nitride films were also deposited by ALD on Cu poly crystal and Cu(111) single crystal substrates for the first time, and a growth rate of ~1ML/ALD cycle was obtained with a B/N ratio of ~2. The realization of a h-BN/Cu heterojunction was the first step towards a graphene/h-BN/Cu structure which has potential application in gateable interconnects. digital.library.unt.edu/ark:/67531/metadc84305/
Family Variables in the Cultural and Psychological Adjustment of Third Culture Kids
Third culture kids are children raised in globally mobile families who have left their culture of origin to reside in a host culture. As this relocation occurs during childhood, the child combines the values, traditions, and norms of both cultures thereby creating a third culture, a unique culture created by the parent’s integration of the home culture, the host culture, and the domains of the organizational culture. Emotional Stability was found to mediate the relationship between family of origin Expression and Composite distress. Though this was the only hypothesized model that was supported, other interesting findings include that when participants were categorized by industry, statistically significant differences were found between Military, Missions, and the Other group on all of the scales. These differences are likely due to a cohort effect, given that the military family mean age was as much as twenty years higher than the other groups. digital.library.unt.edu/ark:/67531/metadc84302/
An Examination of the Relationship Between Values, Family Environment, and Risk Behaviors Among College Students
The purpose of this study was to examine the roles that values and the family environment play in young adult engagement in risky behavior. One hundred seventy-two male and female college students between the ages of 18-25 completed a demographics questionnaire, the Aspirations Index which measures seven life-goal contents that represent different values, the Cognitive Appraisal of Risky Events that assesses young adults’ perceptions of the risks and benefits associated with involvement in risky activities as well as past involvement in risky behaviors and the Family Environment Scale to assess participants' perceptions of their current family environment. A series of regression analyses were then used to assess the relationship between three dimensions of the family environment and risky behavior involvement and the relationship between participants' intrinsic and extrinsic values and perceived positive consequences and negative consequences of risky behavior. Results from this study supported the idea that certain dimensions of the family environment are related to risk-taking behavior in emerging adults; however, contrary to previous research, the relationship dimension of the family environment was not predictive of young adult risk-taking. Moreover, family activities that communicate family values did not contribute any additional information to the prediction of risk-taking behavior. Findings from this study suggest that emerging adult values are related to emerging adult perceptions of the hazards and benefits of risky behavior. Results from this study also highlighted the importance of gender and first-generation college status in predicting risk-taking frequency as well as perceived benefits and hazards of risk-taking. Implications for findings of the current study, limitations, and recommendations for future research are also discussed. digital.library.unt.edu/ark:/67531/metadc84301/
Joint Schemes for Physical Layer Security and Error Correction
The major challenges facing resource constraint wireless devices are error resilience, security and speed. Three joint schemes are presented in this research which could be broadly divided into error correction based and cipher based. The error correction based ciphers take advantage of the properties of LDPC codes and Nordstrom Robinson code. A cipher-based cryptosystem is also presented in this research. The complexity of this scheme is reduced compared to conventional schemes. The securities of the ciphers are analyzed against known-plaintext and chosen-plaintext attacks and are found to be secure. Randomization test was also conducted on these schemes and the results are presented. For the proof of concept, the schemes were implemented in software and hardware and these shows a reduction in hardware usage compared to conventional schemes. As a result, joint schemes for error correction and security provide security to the physical layer of wireless communication systems, a layer in the protocol stack where currently little or no security is implemented. In this physical layer security approach, the properties of powerful error correcting codes are exploited to deliver reliability to the intended parties, high security against eavesdroppers and efficiency in communication system. The notion of a highly secure and reliable physical layer has the potential to significantly change how communication system designers and users think of the physical layer since the error control codes employed in this work will have the dual roles of both reliability and security. digital.library.unt.edu/ark:/67531/metadc84159/
The Effects of Capturing and Searching on the Acquisition of a Simple Arm Position
The present experiment compared two methods of training a simple arm position using auditory feedback: capture and search. The participants were four right-handed female college students. During capture, auditory feedback was delivered by the experimenter after the participant moved along a single axis into the target position. During search, auditory feedback was produced by the computer after the participant left clicked a mouse inside the target location. The results of a multi-element design showed that participants performed more accurately during capture training than search training. Pre-training and post-training probes, during which no auditory feedback was provided, showed similar fluctuations in accuracy across probe types. A retention check, performed seven days after the final training session, showed higher accuracy scores for search than capture, across all four participants. These findings suggest that TAGteach should incorporate an approach similar to search training to improve training outcomes. digital.library.unt.edu/ark:/67531/metadc84215/
Measuring Semantic Relatedness Using Salient Encyclopedic Concepts
While pragmatics, through its integration of situational awareness and real world relevant knowledge, offers a high level of analysis that is suitable for real interpretation of natural dialogue, semantics, on the other end, represents a lower yet more tractable and affordable linguistic level of analysis using current technologies. Generally, the understanding of semantic meaning in literature has revolved around the famous quote ``You shall know a word by the company it keeps''. In this thesis we investigate the role of context constituents in decoding the semantic meaning of the engulfing context; specifically we probe the role of salient concepts, defined as content-bearing expressions which afford encyclopedic definitions, as a suitable source of semantic clues to an unambiguous interpretation of context. Furthermore, we integrate this world knowledge in building a new and robust unsupervised semantic model and apply it to entail semantic relatedness between textual pairs, whether they are words, sentences or paragraphs. Moreover, we explore the abstraction of semantics across languages and utilize our findings into building a novel multi-lingual semantic relatedness model exploiting information acquired from various languages. We demonstrate the effectiveness and the superiority of our mono-lingual and multi-lingual models through a comprehensive set of evaluations on specialized synthetic datasets for semantic relatedness as well as real world applications such as paraphrase detection and short answer grading. Our work represents a novel approach to integrate world-knowledge into current semantic models and a means to cross the language boundary for a better and more robust semantic relatedness representation, thus opening the door for an improved abstraction of meaning that carries the potential of ultimately imparting understanding of natural language to machines. digital.library.unt.edu/ark:/67531/metadc84212/
Modeling Place Vulnerability of HIV/AIDS in Texas
This study provides a measurable model of the concept of place vulnerability for HIV/AIDS that incorporates both community and structural level effects using data provided at the ZIP code level from the Texas Department of State Health Services. Sociological literature on the effects of place on health has been growing but falls short of providing an operational definition of the effects of place on health. This dissertation looks to the literature in medical/health geography to supplement sociology’s understanding of the effects of place on health, to the end of providing a measurable model. Prior research that has recognized the complexity of the effects of place still have forced data into one scale and emphasized individual-level outcomes. A multilevel model allows for keeping the associated spatial unit data, without aggregating or parsing it out for convenience of model fit. The place vulnerability model proposed examines how exposure, capacity and potentiality variables all influence an area’s HIV/AIDS count. To capture the effects of place vulnerability at multiple levels, this dissertation research uses a multilevel zero-inflated poisson (MLZIP) model to examine how factors measured at the ZIP code and county both affect HIV/AIDS counts per ZIP code as an outcome. Furthermore, empirical Bayes estimates are mapped to display how well the model fits across the state of Texas. Limitations of this research include the need to incorporate time, more specific predictors, and individual level factors. The methodology developed permits a more thorough understanding of place effects on the spatial variation of HIV/AIDS. digital.library.unt.edu/ark:/67531/metadc84211/
NNS Use of Adverbs in Academic Writing
Recent studies have begun to redefine the idea of accuracy in second language acquisition to include not only grammatical correctness, but also native-like selection. This is an exploratory study aimed at identifying areas of nonnative-like selection of adverbs, such as sentence position, semantic category preferences, frequency of use and breadth of word choice. Using corpus-linguistic methods it compares the writing of nonnative English speakers at an intermediate and advanced level to both American college students’ writing and published academic writing. It also conducts in-depth case studies of three of the most commonly used adverbs. It finds that while advanced students are grammatically accurate, there are still several ways in which their use of adverbs differs from that of native speakers. digital.library.unt.edu/ark:/67531/metadc84213/
A Comparison of Principals’ Perceptions of Preparedness Based on Leadership Development Opportunities
This research study identified the frequency in which six public school districts in Texas provided principals with effective development opportunities prior to the principalship excluding university or certification programs. A purposive sample of over 200 principals from six school districts in the Dallas/Fort Worth area were asked to participate in the study yielding a response rate of 41%. Respondents identified through a questionnaire their leadership development opportunities and perceptions of preparedness on nine standards common to the profession. Principals were nominally grouped for comparison. The perceptions of preparedness for principals who received effective leadership development opportunities were compared to those who did not receive these same opportunities using an independent samples t-test to determine statistical significance (p < .05). Peer coaching yielded the most statistically significant results in three standards. This finding indicates principals who receive peer coaching prior to the principalship compared to those who did not perceive themselves as more prepared in the areas of community collaboration, political, social, economic, legal, and cultural context, and curriculum, instruction and assessment. Effect size was measured for the statistically significance standards to determine practical significance. Each of the five statistically significant standards yielded a medium effect size indicating that the leadership development methods received by participants explained approximately 30% of the difference. digital.library.unt.edu/ark:/67531/metadc84217/
The Information-Seeking Behavior of Police Officers in Turkish National Police
A current trend that has emerged as a result of the information age is information-seeking behavior. From individuals to large social institutions, information-seeking behavior is utilized to attain a wide variety of goals. This body of work investigates the information-seeking behaviors of police officers who work in police stations in the Turkish National Police force. The study utilizes Leckie et al.’s (1996) model of information-seeking behavior of professionals. The findings indicated that police officers initially consulted their personal knowledge and experience. Next, officers rely upon their colleagues and then official documents. These information sources were consulted in the context of both conducting tasks and staying current. However, contrary to expectation, they rarely consulted informants. In addition police officers rarely consulted printed journals, libraries, books and attendance at conferences as information sources. The results of this study show that there were significant differences in the information sources used by police officers based on their gender in the context of staying current. On the other hand, there were no significant differences in the context of conducting police station tasks, by gender. Surprisingly, there were no significant differences in the information sources used by police officers based on their educational level. There were significant differences in the use of information sources by age, service years in police stations and service years in policing in the context of conducting police station tasks. Lastly, the results of this study indicated that service years in policing and the roles in police station were significantly correlated with the information sources used by police officers regarding staying current. This body of work offers insight into the factors that guide the information-seeking behaviors of police officers. digital.library.unt.edu/ark:/67531/metadc84210/
An Exploration of the Ground Water Quality of the Trinity Aquifer Using Multivariate Statistical Techniques
The ground water quality of the Trinity Aquifer for wells sampled between 2000 and 2009 was examined using multivariate and spatial statistical techniques. A Kruskal-Wallis test revealed that all of the water quality parameters with the exception of nitrate vary with land use. A Spearman’s rho analysis illustrates that every water quality parameter with the exception of silica correlated with well depth. Factor analysis identified four factors contributable to hydrochemical processes, electrical conductivity, alkalinity, and the dissolution of parent rock material into the ground water. The cluster analysis generated seven clusters. A chi-squared analysis shows that Clusters 1, 2, 5, and 6 are reflective of the distribution of the entire dataset when looking specifically at land use categories. The nearest neighbor analysis revealed clustered, dispersed, and random patterns depending upon the entity being examined. The spatial autocorrelation technique used on the water quality parameters for the entire dataset identified that all of the parameters are random with the exception of pH which was found to be spatially clustered. The combination of the multivariate and spatial techniques together identified influences on the Trinity Aquifer including hydrochemical processes, agricultural activities, recharge, and land use. In addition, the techniques aided in identifying areas warranting future monitoring which are located in the western and southwestern parts of the aquifer. digital.library.unt.edu/ark:/67531/metadc84218/
Race Differences in Religiosity, Social Support, and Quality of Life among People Living with HIV/AIDS in Dallas/ Ft. Worth, TX
This study examines race differences and the relationship between religiosity/ spirituality and social support on quality of life (QOL) among people living with HIV/AIDS in Dallas/Ft. Worth, TX. The data were obtained from the Project VOICES research study conducted by the Center of Psychosocial Health Research at University of North Texas in 2003. This study explores the hypotheses that religiosity/spirituality and social support positively influences quality of life among people living with HIV/AIDS. The current study uses a diverse, gender-balanced sample consisting of African Americans (n = 156), aged 20-68, 47% male, 52% female and 1% transgendered) and Non-African Americans (n = 131), aged 19-65, 50% male, 46% female and 3% transgendered) (Caucasian, Latino, & others) to evaluate the relationship among variables of interest. Multiple regression analyses revealed that social support was a significant factor explaining quality of life (QOL) for African Americans when controlling for medical variables but did not for non-African Americans. Religiosity/spirituality was not found to be significant in this study. The implications of the findings are discussed. digital.library.unt.edu/ark:/67531/metadc84214/
Aerospace and Defense Industries Online Recruiting of College and University Graduates: Strategies Toward Defining a Comprehensive Informational Benchmark
This qualitative, inductive study analyzed online recruiting information posted at the websites of five major aerospace and defense corporations to recruit college juniors, seniors, and recent graduates. Recruitment of this group is critical to staff the personnel for the scientific, technical, and management needs of aerospace and defense industries. The study sought: (1) to determine the use of multiple recruitment factors inferred from the literature and recommended for successful recruitment of college graduates, (2) to determine use of online social media (Facebook, Twitter, LinkedIn) to recruit this population, and (3) to explore commonalities among these corporations regarding online recruiting information to determine if a model for online recruitment now exists. A matrix of recruitment factors was developed from a review of the literature on the personnel needs of this industry and on effective recruiting factors for this group. Content analysis involved filtering information at each website with the matrix. Conclusions of this study include: (1) the matrix of recruitment factors and the rating scale developed for the purposes of this study provide a tool for researching, documenting, and comparing recruitment information on the internet; (2) that while these corporations represent the latest applications in technology in their manufacturing processes and products, they do not use social networking technology to the extent the popular and scholarly literature indicate is typical for the target group. Given that the current generation exhibits extensive use of social media, several of these corporations’ websites appear not to utilize this networking technology. Informally, these corporations argue that cyber-security prevents extensive use of social networking sites. Thus, these corporations must determine how to maintain cyber-security while at the same time adopting more accepted use of social networking platforms. digital.library.unt.edu/ark:/67531/metadc84219/
Faunal Exploitation during the Depopulation of the Mesa Verde Region (A. D. 1300): A Case Study of Goodman Point Pueblo (5MT604)
This analysis of faunal remains from Goodman Point Pueblo (5MT604), a large village occupied just before the ancestral Puebloans permanently left southwestern Colorado at the end of the thirteenth century, explores the effect of dietary stress during abandonment in the Four Corners region. As archaeologists, we interpret what these former cultures were like and what resources they used through what they left behind. By specifically looking at faunal remains, or remains from food resources, environmental change and dietary stress can be assessed. Identifications of taxa identified at Goodman Point are made explicit via a systematic paleontology. This is followed by site-level taxonomic abundances and spatial analysis. Then, effects of technological innovations, environmental change, and sample quality are examined as alternate explanations of shifts in foraging efficiency, particularly related to animal hunting. Analyzing why and if the availability of faunal resources changes over time helps to clarify why the ancestral Puebloans left southwestern Colorado. digital.library.unt.edu/ark:/67531/metadc84216/
Re-Envisioning an Eighteenth-Century Artifact: A Postmodern Reading of Tristram Shandy
The interjection of a new and dynamically different reading of Lawrence Sterne’s Tristram Shandy is imperative, if scholars want to clearly see many of the hidden facets of the novel that have gone unexamined because of out-dated scholarship. Ian Watt’s assumption that Sterne “would probably have been the supreme figure among eighteenth-century novelists” (291) if he had not tried to be so odd, and the conclusion that he draws, that “Tristram Shandy is not so much a novel as a parody of a novel” (291), is incorrect. Throughout the thesis, I argue that Sterne was not burlesquing other novelists, but instead, was engaging with themes that are now being examined by postmodern theories of Jacques Derrida, Michel Foucault, and Jean François Lyotard: themes like the impenetrability of identity (“Don’t puzzle me” (TS 7.33.633)), the insufficiency of language (“Well might Locke write a chapter upon the imperfections of words” (5.6.429)), and the unavailability of permanence (“Time wastes too fast” (9.8.754)). I actively engage with their theories to deconstruct unexamined themes inside Tristram Shandy, and illuminate postmodern elements inside the novel. However, I do not argue that Tristram Shandy is postmodern. Instead, I argue that if the reader examines the novel outside of its usual context inside the eighteenth-century novel, there are themes that are apparent in the narrative which have gone unexamined because of the way it has been classified inside academia, and that postmodernist theory allows for these themes to be re-examined in the postmodern culture in which we now reside. digital.library.unt.edu/ark:/67531/metadc84181/
Resilience and Health Outcomes in Patients with Traumatic Injury
Due to the increasing healthcare costs and reduced length of hospital stay it is becoming increasingly important to identify individuals who are ‘at risk’ of experiencing long-term health issues. The purpose of the study was to: (1) determine if resilience, self efficacy and depression changed from inpatient to 3-month follow up; (2) examine the relationship between resilience, self efficacy, depression, and quality of life (social roles/activity limitations) at inpatient and 3-month follow up; and (3) identify if resilience at inpatient is related to change scores in selfefficacy and depression at 3-month follow up. Results from the paired sample t-test indicated that participants did not experience a significant change from inpatient to 3-month follow up in resilience or self-efficacy, but a significant decrease in depression was observed. Findings also indicated significant correlations between resilience, self-efficacy, and depression during inpatient stay and resilience, self-efficacy, depression, and quality of life at 3-month follow up. However, there was no relationship found between resilience and change scores in self-efficacy and depression. Future resilience research should continue to identify the variables that are most strongly related to resilience so effective interventions can be developed that improve rehabilitation outcomes, decrease secondary and chronic conditions as well as aid in the successful reintegration of individuals into their lives after a traumatic injury. digital.library.unt.edu/ark:/67531/metadc84187/
A Real-Time Electronic Sound Analysis System with Graphical User Interface
Noise-induced hearing loss is a serious problem common to musical environments. Current dosimetry technology is primarily designed for industrial environments and not suited for musical settings. At present, there are no government regulations that apply to the educational music environment as it relates to monitoring and prevention of hearing loss. Also, no system exists than can serve as a proactive tool in observation and reporting of sound exposure levels with the goal of hearing conservation. Newly proposed system takes a software based approach in designing a proactive dosimetry system that can assess the risk of sound noise exposure. It provides real-time feedback trough a graphical user interface that is capable of database storage for further study. digital.library.unt.edu/ark:/67531/metadc84180/
User-Centered Evaluation of the Quality of Blogs
Blogs serve multiple purposes, resulting in several types of blogs that vary greatly in terms of quality and content. It is important to evaluate the quality of blogs, which requires appropriate evaluation criteria. Unfortunately, there are minimal studies on framework and the specific criteria and indicators for evaluating the quality of blogs. Moreover, quality is related to user perception, and should therefore be evaluated by the receivers. This dissertation examines the criteria and indicators that blog users consider important for evaluating the quality of blogs, and develops a user-centered framework for evaluating quality by conducting user surveys and post-survey email interviews. The personal characteristics that affect the users’ choices of criteria to evaluate the quality of blogs are examined as well. The study’s findings include 1) the criteria that users consider important when evaluating the quality of blogs are content quality, usability, authority, and blog credibility; 2) the indicators that blog users consider most important for evaluating the quality of blogs are understandability, accuracy, believability, currency, ease of use, and navigation; and 3) gender, education level, age, profession, purpose of use, and specific interests affect the user’s choices of criteria for evaluating the quality of blogs. Future research may involve exploring and applying the framework developed in this study to build automatic quality blog identification system for the purpose of assisting web users and information specialists to identify quality blogs. digital.library.unt.edu/ark:/67531/metadc84188/
Evaluating the Effects of Public Postings on Energy Conservation Behavior at a Public University
This study evaluated the effects of public postings on energy conservation behavior at a public university, using a multiple baseline design across three settings; bathrooms break rooms, and conference rooms. The behavior of building occupants was recorded to assess the frequency at which those individuals would turn lights off upon exiting an unoccupied room. The independent variables implemented by experimenters (light-switch plate stickers and laminated signs) had little to no effects on cumulative instances of lights turned off however, the installation of motion sensor lights produced better results. Across all conditions, lights were turned off most frequently in conference rooms (65% of observations) followed by break rooms (9% of observations), and bathrooms (3% of observations). digital.library.unt.edu/ark:/67531/metadc84184/
Effects of a Play-Based Teacher Consultation (PBTC) Program on Interpersonal Skills of Elementary School Teachers in the Classroom
The purpose of this study was to examine the effectiveness of a play-based teacher consultation (PBTC) program on individual teachers’ interpersonal classroom behaviors and teacher-child relationships. The research questions addressed the application of child-centered play therapy principles and PBTC increasing teacher responsiveness, decreasing teacher criticism, and enhancing teachers‟ perceptions of the teacher-child relationship in elementary school classrooms. Single-case design was utilized to examine eight teachers‟ perceptions over 16 weeks. The sample included 8 White female teachers from three local elementary schools. Teacher ages ranged from 28 to 59 years old. There were 5 kindergarten, 1 first grade, and 2 second grade teachers. The teachers participated in one educational training session followed by play sessions with children of focus and interactive modeling sessions. Trained observers, blind to the study’s purpose, utilized the Interaction Analysis System in classroom observations of the teachers, three times per week, to examine teachers’ interpersonal skills. Additionally, the teachers completed the Student Teacher Relationship Scale for the children of focus before and after the play session phase to examine change in the teacher-child relationship. Visual analysis of the data indicated the PBTC’s overall positive impact. 5 out of 8 teachers demonstrated increases in teacher responding scores at mildly to very effective criteria levels. All 8 teachers demonstrated decreases teacher criticism at effective to very effective criteria levels. The teacher-child relationships indicated mixed results, with 5 out of 8 teachers indicating positive changes in teacher-child relationships. Discussion includes implications for future research regarding single-case design, measurement of teacher change, and modifications of the PBTC model. digital.library.unt.edu/ark:/67531/metadc84185/
Factors Affecting Police Officers' Acceptance of GIS Technologies: A study of the Turkish National Police
The situations and problems that police officers face are more complex in today’s society, due in part to the increase of technology and growing complexity of globalization. Accordingly, to solve these problems and deal with the complexities, law enforcement organizations develop and apply new techniques and methods such as geographic information systems (GIS). However, the successful implementation of a new technology does not just depend on providing perfect technical support, but effective and active interaction between the user and system. For this reason, research examining user acceptance of GIS technologies provides a valuable source to investors and designers to predict whether the results of the technology will meet user expectations; understanding the factors that influence user acceptance is vitally important to make the system more usable and preferable. This study attempts to explain Turkish National Police officers’ beliefs about and behaviors toward GIS applications by using the technology acceptance models. It contributes to the technology acceptance literature by testing the proposed model in a rarely studied organization: law enforcement. Regarding methodology, I distributed a survey questionnaire in Turkey; the unit of analysis was the law enforcement officers in the Turkish National Police (TNP). In order to analyze the data derived from the survey instrument, structural equation modeling (SEM), a multivariate statistical technique, was used to analyze the quantitative data by utilizing the AMOS 16.0 software. The analysis resulted in good model fit, and 6 of the 7 hypotheses were supported. digital.library.unt.edu/ark:/67531/metadc84182/
A Systematic Review of Research on After-Death Communication (ADC)
In this study, after-death communication (ADC) is defined as spontaneously occurring encounters with the deceased. Reported occurrences of ADC phenomena range widely among published ADC research studies, so a systematic review of 35 studies was conducted. A rubric was developed to evaluate the methodological quality; final inter-rater reliability among three raters was r = .90. Results were used to rank the studies; the methodologically strongest studies were used to arrive at best estimate answers to four research questions/subquestions: (1) How common are experiences of ADC? How does occurrence vary by gender, age, marital status, ethnicity, religious practice, religious affiliation, financial status, physical health, educational level, and grief status? (2) To what extent do ADCrs report ADC experiences to be beneficial and/or detrimental? What are the leading benefits and/or detriments? (3) What is the incidence of research studies in which the researchers mentioned that the research participants appeared mentally healthy? (4) What is the incidence of sensory modalities—for example, visual, auditory, and kinesthetic—in which ADCs occur? Best estimate results were compiled into a one-page fact sheet that counselors and others can use to educate people who seek empirically-based information about ADC. digital.library.unt.edu/ark:/67531/metadc84284/
The Influence of Interactivity and Online Store Atmospherics of a 3-D Retail Store in Second Life on Consumer Purchase Intentions
Second Life, a 3-D virtual world, has evolved as a shopping channel for both consumers and retailers. This channel of retailing offers interactive environment, allows designing atmospherics, and provides enjoyable shopping experience as compared to website stores. The purpose of the study was: (1) to identify the key features of Second Life stores and (2) to determine the relationship of the Second Life store features with consumer purchase intentions. The online survey was administered in Second Life by an external research agency, and 249 usable surveys were collected. The data were analyzed utilizing factor analysis and regression. Three key features of Second Life stores were explored in this study. These three features were: (1) interactivity via the two components of two-way communication and active control, (2) store atmospherics, and (3) shopping enjoyment. Regression analysis showed that shopping enjoyment and two-way communication (i.e., the presence of an avatar sales representative) were significant predictors of purchase intention in Second Life stores, while active control and store atmospherics did not influence purchase intentions. digital.library.unt.edu/ark:/67531/metadc84289/
Cu Electrodeposition on Ru-Ta and Corrosion of Plasma Treated Cu in Post Etch Cleaning Solution
In this work, the possibility of Cu electrodeposition on Ru-Ta alloy thin films is explored. Ru and Ta were sputter deposited on Si substrate with different composition verified by RBS. Four point probe, XRD, TEM and AFM were used to study the properties of Ru-Ta thin films such as sheet resistance, crystallinity, grain size, etc. Cyclic voltammetry is used to study the Cu electrodeposition characteristics on Ru-Ta after various surface pretreatments. The results provide insights on the removal of Ta oxide such that it enables better Cu nucleation and adhesion. Bimetallic corrosion of Cu on modified Ru-Ta surface was studied in CMP related chemicals. In Cu interconnect fabrication process, the making of trenches and vias on low-k dielectric films involves the application of fluorocarbon plasma etch gases. Cu microdots deposited on Ru and Ta substrate were treated by fluorocarbon plasma etch gases such as CF4, CF4+O2, CH2F2, C4F8 and SF6 and investigated by using x-ray photoelectron spectroscopy, contact angle measurement and electrochemical techniques. Micropattern corrosion screening technique was used to measure the corrosion rate of plasma treated Cu. XPS results revealed different surface chemistry on Cu after treating with plasma etching. The fluorine/carbon ratio of the etching gases results in different extent of fluorocarbon polymer residues and affects the cleaning efficiency and Cu corrosion trends. digital.library.unt.edu/ark:/67531/metadc84286/
Synthetic Cannabinoid Usage among College Students: The Example of K2 and Spice
The primary goal of this study was to investigate the awareness and prevalence of Spice and K2 usage among a population of college students, as well as the demographics of such users. The study also sought to determine whether or not students prefer these products over natural cannabis, in addition to examining the most popular methods of obtainment and the most commonly reported side effects of K2 and Spice usage. Participants consisted of 643 undergraduate students enrolled at the University of North Texas during the fall 2011 semester. Findings indicate that while students exhibit a relatively high awareness of K2 and Spice, usage of these products is not a prevalent occurrence. Implications of the findings are discussed. digital.library.unt.edu/ark:/67531/metadc84283/
Toward an Ecological Understanding of the Vendée: Old Myths and New Paradigms
This work explores the motivations of the two major parties in the civil war in the Vendée from 1793 to 1796. It suggests that traditional understandings overemphasize simplistic notions of the idealistic crusade; the Revolutionaries fought for Republican ideals, while the locals fought to defend traditional Catholicism. This thesis suggests that the major motive for both sides was a fight for survival that was framed and expressed in political and religious terms rather than motivated by them. The reason that these motives have been confused is a long misunderstood connection between the means of discourse, the structure of social values, and their connection to any individual’s perceived sense of safety, which suggests an ecological, or holistic, rather than a Manichaean framework. digital.library.unt.edu/ark:/67531/metadc84285/
Missing Data Treatments at the Second Level of Hierarchical Linear Models
The current study evaluated the performance of traditional versus modern MDTs in the estimation of fixed-effects and variance components for data missing at the second level of an hierarchical linear model (HLM) model across 24 different study conditions. Variables manipulated in the analysis included, (a) number of Level-2 variables with missing data, (b) percentage of missing data, and (c) Level-2 sample size. Listwise deletion outperformed all other methods across all study conditions in the estimation of both fixed-effects and variance components. The model-based procedures evaluated, EM and MI, outperformed the other traditional MDTs, mean and group mean substitution, in the estimation of the variance components, outperforming mean substitution in the estimation of the fixed-effects as well. Group mean substitution performed well in the estimation of the fixed-effects, but poorly in the estimation of the variance components. Data in the current study were modeled as missing completely at random (MCAR). Further research is suggested to compare the performance of model-based versus traditional MDTs, specifically listwise deletion, when data are missing at random (MAR), a condition that is more likely to occur in practical research settings. digital.library.unt.edu/ark:/67531/metadc84282/
Void Growth and Collapse in a Creeping Single Crystal
Aircraft engine components can be subjected to a large number of thermo-mechanical loading cycles and to long dwell times at high temperatures. In particular, the understanding of creep in single crystal superalloy turbine blades is of importance for designing more reliable and fuel efficient aircraft engines. Creep tests on single crystal superalloy specimens have shown greater creep strain rates for thinner specimens than predicted by current theories. Therefore, it is necessary to develop a more predictive description of creep processes in these materials for them to be used effectively. Experimental observations have shown that the crystals have an initial porosity and that the progressive growth of these voids plays a major role in limiting creep life. In order to understand void growth under creep in single crystals, we have analyzed the creep response of three dimensional unit cells with a single spherical void under different types of isothermal creep loading. The growth behavior of the void is simulated using a three dimensional rate dependent crystal plasticity constitutive relation in a quasi-static finite element analysis. The aim of the present work is to analyze the effect of stress traixiality and Lode parameter on void growth under both constant true stress and constant engineering stress isothermal creep loading. digital.library.unt.edu/ark:/67531/metadc84281/
The Brazos Valley Groundwater Conservation District: A Case Study in Texas Groundwater Conservation
This thesis examines the history of groundwater management through the development of groundwater conservation districts in Texas. Political, economic, ideological, and scientific understandings of groundwater and its regulation varied across the state, as did the natural resource types and quantities, which created a diverse and complicated position for lawmakers and landowners. Groundwater was consistently interpreted as a private property right and case law protected unrestricted use for the majority of the twentieth-century even as groundwater resources crossed property and political boundaries, and water tables declined particularly during the second-half of the century. The case study of the Brazos Valley Groundwater Conservation District describes the complicated history of groundwater in Texas as the state attempted to balance natural resource legislation and private property rights and illuminate groundwater’s importance for the future. digital.library.unt.edu/ark:/67531/metadc84287/
Application of FTIR for Quantification of Alkali in Cement
Alkali-silica reaction (ASR) in cement is a major contributor to failure of cement structures around the world, causing increased repair costs and possible rebuild expenses. Alkali levels are indicative of the potential for ASR and are therefore measured and quantified. A linear correlation relating cement alkali concentration measured by X-ray fluorescence spectroscopy (XRF) and peak ratio measured by Fourier transform infrared spectroscopy (FTIR) is developed. Regression analysis of plots correlating alkali content measured by FTIR absorption band (750 cm-1/923 cm-1) ratio versus equivalent alkali (Na2O)e (%Na2O + 0.658 % K2O) quantified by XRF show linear correlation coefficient, R2, of 0.97. Results of this investigation are discussed in terms of microstructural disorder coefficient Cd which is a reactivity criterion for ASR-susceptible aggregates proposed by Bachiorrini [31]. XRF is a popular technique for alkali quantification but FTIR is faster, safer, and less expensive technique compared to XRF. Portable instrumentation is available for both techniques but FTIR systems are less expensive. digital.library.unt.edu/ark:/67531/metadc84280/
Computational Investigation of Molecular Optoelectronic and Biological Systems
The scope of work in this dissertation has comprised several major investigations on applications and theoretical studies of ab initio quantum mechanics and density functional theory where those techniques were applied to the following: (i) investigation of the performance of density functionals for the computations of molecular properties of 3d transition metal containing systems; (ii) guidance for experimental groups for rational design of macrometallocyclic multinuclear complexes with superior π-acidity and π-basicity that are most suitable for p- and n-type semiconductors of metal-organic molecules and nanomaterials; (iii) investigation of the metallo-aromaticity of multi-nuclear metal complexes; (iv) investigation of the kinetics and thermodynamics of copper-mediated nitrene insertion into C-H and H-H bond; and (v) accurate computations of dissociation energies of hydrogen-bonded DNA duplex moieties utilizing the resolution of identity correlation consistent composite approach (RI-ccCA). digital.library.unt.edu/ark:/67531/metadc84288/