You limited your search to:

  Partner: UNT Libraries
Corrosion Protection of Aerospace Grade Magnesium Alloy Elektron 43™ for Use in Aircraft Cabin Interiors
Magnesium alloys exhibit desirable properties for use in transportation technology. In particular, the low density and high specific strength of these alloys is of interest to the aerospace community. However, the concerns of flammability and susceptibility to corrosion have limited the use of magnesium alloys within the aircraft cabin. This work studies a magnesium alloy containing rare earth elements designed to increase resistance to ignition while lowering rate of corrosion. The microstructure of the alloy was documented using scanning electron microscopy. Specimens underwent salt spray testing and the corrosion products were examined using energy dispersive spectroscopy. digital.library.unt.edu/ark:/67531/metadc283846/
Media and Corporate Social Responsibility: How Leading Business Magazines Frame a Controversial Concept
Corporate social responsibility (CSR) is an emerging concept that continues to play a controversial role in the business world. Different CSR theories and ethical foundations inform different approaches to embedding socially responsible behavior into today's business functions. As technology, globalization, and economic challenges change the corporate world, the meaning and application of CSR also changes. While no empirical evidence of CSR's impact on performance exists, many corporations operate under the assumption that CSR holds significant value. This study examines the framing of CSR in stories published by leading business magazines between 2008 and 2012. By examining the presentation of CSR concepts, the resulting analysis can provide important conclusions for corporations, public relations practitioners, mass media, and consumers. This study resulted in a hierarchical pyramid of frames that organizes the framing of CSR in business magazines into three layers: category, motivation, and classification as either responsible behavior or irresponsible behavior. These results lead to recommendations for future CSR research, including the need for quantitative evidence of a connection or disconnection between CSR and profitability. digital.library.unt.edu/ark:/67531/metadc283861/
Is It More Advantageous to Administer Libqual+® Lite Over Libqual+®? an Analysis of Confidence Intervals, Root Mean Square Errors, and Bias
The Association of Research Libraries (ARL) provides an option for librarians to administer a combination of LibQUAL+® and LibQUAL+® Lite to measure users' perceptions of library service quality. LibQUAL+® Lite is a shorter version of LibQUAL+® that uses planned missing data in its design. The present study investigates the loss of information in commonly administered proportions of LibQUAL+® and LibQUAL+® Lite when compared to administering LibQUAL+® alone. Data from previous administrations of LibQUAL+® protocol (2005, N = 525; 2007, N = 3,261; and 2009, N = 2,103) were used to create simulated datasets representing various proportions of LibQUAL+® versus LibQUAL+® Lite administration (0.2:0.8, 0.4:0.6. 0.5:0.5, 0.6:0.4, and 0.8:0.2). Statistics (i.e., means, adequacy and superiority gaps, standard deviations, Pearson product-moment correlation coefficients, and polychoric correlation coefficients) from simulated and real data were compared. Confidence intervals captured the original values. Root mean square errors and absolute and relative biases of correlations showed that accuracy in the estimates decreased with increase in percentage of planned missing data. The recommendation is to avoid using combinations with more than 20% planned missing data. digital.library.unt.edu/ark:/67531/metadc283825/
Confirming the Constructs of the Adlerian Personality Priority Assessment (Appa)
The primary purpose of this study was to confirm the four-factor structure of the 30-item Adlerian Personality Priority Assessment (APPA) using a split-sample cross-validation confirmatory factor analysis (CFA). The APPA is an assessment, grounded in Adlerian theory, used to conceptualize clients based on the four personality priorities most commonly used in the Adlerian literature: superiority, pleasing, control, and comfort. The secondary purpose of this study was to provide evidence for discriminant validity, examine predictive qualities of demographics, and explore the prevalence of the four priorities across demographics. For the cross validation CFA, I randomly divided the sample, 1210 undergraduates, at a large public research university (53% Caucasian, 13.1% Hispanic/Latino(a), 21.4% African American, 5.4% American Indian, and 5.8% biracial; mean age =19.8; 58.9% females), into two equal subsamples. I used Subsample 1 (n = 605) to conduct the initial CFA. I held out Subsample 2 (n = 605) to test any possible model changes resulting from Subsample 1 results and to provide further confirmation of the APPA's construct validity. Findings from the split-sample cross-validation CFA confirmed the four-factor structure of the APPA and provided support for the factorial/structure validity of the APPA's scores. Results also present initial evidence of discriminant validity and support the applicability of the instrument across demographics. Overall, these findings suggest Adlerian counselors can confidently use the APPA as a tool to conceptualize clients. digital.library.unt.edu/ark:/67531/metadc283856/
Environmental Philosophy and the Ethics of Terraforming Mars: Adding the Voices of Environmental Justice and Ecofeminism to the Ongoing Debate
Questions concerning the ethics of terraforming Mars have received some attention from both philosophers and scientists during recent decades. A variety of theoretical approaches have been supplied by a number of authors, however research pursuant to this thesis has indicated at least two major blindspots in the published literature on the topic. First, a broad category of human considerations involving risks, dangers, and social, political, and economic inequalities that would likely be associated with efforts to terraform Mars have been woefully overlooked in the published literature to date. I attempt to rectify that oversight by employing the interpretive lens of environmental justice to address questions of environmental colonialism, equality in terms of political participation and inclusion in decision making structures, risks associated with technological progressivism, and responses to anthropogenic climate change. Only by including the historically marginalized and politically disenfranchised "voices," of both humans and nonhumans, can any future plan to terraform Mars be deemed ethical, moral or just according to the framework provided by environmental justice. Furthermore, broader political inclusion of this sort conforms to what ecofeminist author Val Plumwood calls the "intentional recognition stance" and provides an avenue through which globally societies can include nonanthropocentric considerations in decision making frameworks both for questions of terraforming Mars and also for a more local, contemporary set of environmental issues. The second blindspot I seek to correct concerns motivations for attempting terraforming on Mars previously inadequately philosophically elaborated in the published discourse. Specifically, the nonanthropocentric considerations postulated in the second chapter by various authors writing about terraforming, and elaborated in third with regard to environmental justice, reach their culmination in an ecofeminist ethic of care, sustainability, reproduction, and healthy growth which I uniquely elaborate based on a metaphorical similarity to the relationship between a gardener and a garden. Although at first glance, this metaphor may appear overly domineering, or uncritically paternalistic, I argue a deep understanding of its implications will be eminently beneficial for discussions of what is moral, good, right, and just to do regarding not only whether or not to terraform Mars, but for contemporary environmental concerns as well. Ultimately, extreme caution and a robust precautionary principle are the moral prescriptions arrived at in this thesis for the near term future. Until a sustainable civilization and just society can be established and effectively maintained, efforts to terraform and colonize another planet are practically certain to produce as much that is undesirable as that which might be good. digital.library.unt.edu/ark:/67531/metadc283810/
A Comparative Study of Non Linear Conjugate Gradient Methods
We study the development of nonlinear conjugate gradient methods, Fletcher Reeves (FR) and Polak Ribiere (PR). FR extends the linear conjugate gradient method to nonlinear functions by incorporating two changes, for the step length αk a line search is performed and replacing the residual, rk (rk=b-Axk) by the gradient of the nonlinear objective function. The PR method is equivalent to FR method for exact line searches and when the underlying quadratic function is strongly convex. The PR method is basically a variant of FR and primarily differs from it in the choice of the parameter βk. On applying the nonlinear Rosenbrock function to the MATLAB code for the FR and the PR algorithms we observe that the performance of PR method (k=29) is far better than the FR method (k=42). But, we observe that when the MATLAB codes are applied to general nonlinear functions, specifically functions whose minimum is a large negative number not close to zero and the iterates too are large values far off from zero the PR algorithm does not perform well. This problem with the PR method persists even if we run the PR algorithm for more iterations or with an initial guess closer to the actual minimum. To improve the PR algorithm we suggest finding a better weighing parameter βk, using better line search method and/or using specific line search for certain functions and identifying specific restart criteria based on the function to be optimized. digital.library.unt.edu/ark:/67531/metadc283864/
Tax Compliance in a Social Setting: the Influence of Norms, Perceptions of Fairness, and Trust in Government on Taxpayer Compliance
Many taxing authorities, including those in the United States (U.S.), rely on voluntary tax compliance and continually search for ways to increase tax revenues. Most of these methods are costly and labor intensive, such as audits and penalties for noncompliance. Prior tax compliance research has heavily investigated the influence that economic factors, such as tax rates and penalties, have on individual compliance intentions. However, economic models fail to fully predict individual tax compliance. Psychology literature suggests that social factors may also play an important role in individual tax compliance decisions. The purpose of this study is to examine the influence that social and psychological factors have on individuals' tax compliance intentions. Specifically, a model of taxpayer compliance is hypothesized that suggests that norms, perceived fairness of the tax system, and trust in government have a significant influence on compliance intentions. Results of a survey of 217 U.S. taxpayers found support for the influence of social factors on tax compliance. This research concludes that social norms have an indirect influence on compliance intentions through internalization as personal norms. Specifically, as the strength of social norms in favor of tax compliance increase, personal norms of tax compliance also increase, and this leads to a subsequent increase in compliance intentions. This dissertation also finds that trust in government and the perceived fairness of the tax system have a significant influence on compliance intentions. Supplemental analyses indicate that trust in government fully mediates the relationship between perceived fairness of the tax system and compliance intentions. This research offers several contributions to accounting literature and provides valuable insight for taxing authorities. First, this study examines taxpayer compliance from a psychological, rather than an economics driven, perspective. The suggested model of taxpayer compliance posits that social norms have a significant influence on compliance intentions. This information may help taxing authorities develop less costly and more effective strategies for increasing taxpayer compliance. This study also examines the influence that perceived fairness of the tax system has on compliance intentions. This is a widely debated topic in the media and social settings and may have a particularly strong influence on compliance intentions during these times of political and social arguments regarding tax equity. Finally, trust in government around the world has seen a continual decline. The results indicate that decreased trust in government and decreased perceived fairness of the tax system lead to decreased intention to comply with tax laws. Such information may help governments understand actions they can take to improve tax compliance. digital.library.unt.edu/ark:/67531/metadc283805/
Innovations in Musical Texture and Aural Perspective: Steven Mackey's See Ya Thursday for Solo Marimba
This dissertation and accompanying lecture recital explore the unique textural features in the works of Steven Mackey as exhibited in See Ya Thursday (1993).A rigorous formal, harmonic, and motivic analysis will highlight the compositional characteristics of textural structure and aural perspective that exist in the work. Illumination of these compositional elements can help to identify and minimize the technical complexities that exist within this piece for the performer. In addition, this document provides brief biographical information on Steven Mackey and his works, and on See Ya Thursday as it relates to other pieces in the advanced marimba literature. Finally, it is the aim of the author to add a resource to the relatively limited amount of research on Steven Mackey with this analysis of See Ya Thursday. digital.library.unt.edu/ark:/67531/metadc283817/
An Exploration of Teachers' Adoption of the Bring Your Own Technology Program
The purpose of this study was to explore teachers' concerns, use, and actual practices in their adoption of the bring your own technology (BYOT) initiative. Twelve secondary teachers in a private school setting participated in this study. The participants represented all content areas including reading, math, science, and electives. The private school was in its third year of implementing BYOT. This case study incorporated multiple methods to collect data to gain a better understanding of teachers' adoption of an innovation, BYOT. The concerns-based adoption model (CBAM) was used as a theoretical framework. All three CBAM tools provided data: the Stages of Concern Questionnaire (SoCQ), levels of use interview protocol (LoUIP), and the innovation configuration (IC) map. Twelve of the participants completed the SoCQ across three different points in time. Six of the twelve teachers participated in three one-on-one interviews, including the LoUIP. Additionally, six teachers were observed in their classrooms during instruction. After triangulating all pieces of data, the majority of teachers had highest concerns related to self. Teachers were concerned about their ability to implement the innovation and managing BYOT in their classroom. Four of the six teachers had a level of use (LoU) at mechanical, and two teachers had a LoU at routine. The teachers' LoU indicated that they are using BYOT in the classroom; however, the majority of teachers observed had adoption practices mostly in the non-ideal variations of IC. The teachers' LoU and IC indicated that teachers had implemented BYOT in their own way and not necessarily in alignment with the campus' vision or expectations. This case study had several limitations, including the small number of participants and the brevity of classroom observations. Additionally, this study was limited to one school setting. Recommendations for future research include exploring teachers' adoption of BYOT in various school settings (i.e., both public and private schools) and teachers at the elementary, middle, and high school levels. Researchers should consider exploring the impact of specific interventions and support on teachers' adoption. digital.library.unt.edu/ark:/67531/metadc283863/
The Integration of Western Techniques with East Asian Philosophies in Isang Yun's Quartett Für Horn, Trompete, Posaune Und Klavier
Korean composer Isang Yun (1917-1995) was one of the few successful Asian avant-garde composers to blend philosophical elements from East Asia with Western techniques such as the twelve-tone method, Hauptton, Hauptklang, and Umspielung. In addition to the integration of Western and Eastern influences, a significant feature of Yun´s compositional language, found throughout his oeuvre, is the application of East Asian philosophical tenets into his works. The purpose of this dissertation is to develop a greater understanding of Isang Yun's life and music, more specifically the Quartett für Horn, Trompete, Posaune und Klavier. The dissertation is divided into five chapters. The first chapter of the dissertation presents introductory data, including the purpose and significance of the study. The second chapter provides pertinent biographical facts about Isang Yun and his works, obtained through research of authoritative books, journal articles, and interviews. The third chapter offers references to traditional Korean brass instruments in terms of their historical background, structure, and timbre. In addition, it also focuses on the processes by which Yun incorporated the compositional techniques of Hauptton, Hauptklang, and Umspielung to the work and their relation to Tao philosophy. The fourth chapter consists of an analytical and stylistic study of the Quartett; Yun's compositional language and formal structure are examined based on a stylistic assessment of selected examples from the work. The fifth and last chapter is a conclusion. digital.library.unt.edu/ark:/67531/metadc283829/
Detection of Temporal Events and Abnormal Images for Quality Analysis in Endoscopy Videos
Recent reports suggest that measuring the objective quality is very essential towards the success of colonoscopy. Several quality indicators (i.e. metrics) proposed in recent studies are implemented in software systems that compute real-time quality scores for routine screening colonoscopy. Most quality metrics are derived based on various temporal events occurred during the colonoscopy procedure. The location of the phase boundary between the insertion and the withdrawal phases and the amount of circumferential inspection are two such important temporal events. These two temporal events can be determined by analyzing various camera motions of the colonoscope. This dissertation put forward a novel method to estimate X, Y and Z directional motions of the colonoscope using motion vector templates. Since abnormalities of a WCE or a colonoscopy video can be found in a small number of frames (around 5% out of total frames), it is very helpful if a computer system can decide whether a frame has any mucosal abnormalities. Also, the number of detected abnormal lesions during a procedure is used as a quality indicator. Majority of the existing abnormal detection methods focus on detecting only one type of abnormality or the overall accuracies are somewhat low if the method tries to detect multiple abnormalities. Most abnormalities in endoscopy images have unique textures which are clearly distinguishable from normal textures. In this dissertation a new method is proposed that achieves the objective of detecting multiple abnormalities with a higher accuracy using a multi-texture analysis technique. The multi-texture analysis method is designed by representing WCE and colonoscopy image textures as textons. digital.library.unt.edu/ark:/67531/metadc283849/
Automated Real-time Objects Detection in Colonoscopy Videos for Quality Measurements
The effectiveness of colonoscopy depends on the quality of the inspection of the colon. There was no automated measurement method to evaluate the quality of the inspection. This thesis addresses this issue by investigating an automated post-procedure quality measurement technique and proposing a novel approach automatically deciding a percentage of stool areas in images of digitized colonoscopy video files. It involves the classification of image pixels based on their color features using a new method of planes on RGB (red, green and blue) color space. The limitation of post-procedure quality measurement is that quality measurements are available long after the procedure was done and the patient was released. A better approach is to inform any sub-optimal inspection immediately so that the endoscopist can improve the quality in real-time during the procedure. This thesis also proposes an extension to post-procedure method to detect stool, bite-block, and blood regions in real-time using color features in HSV color space. These three objects play a major role in quality measurements in colonoscopy. The proposed method partitions very large positive examples of each of these objects into a number of groups. These groups are formed by taking intersection of positive examples with a hyper plane. This hyper plane is named as 'positive plane'. 'Convex hulls' are used to model positive planes. Comparisons with traditional classifiers such as K-nearest neighbor (K-NN) and support vector machines (SVM) proves the soundness of the proposed method in terms of accuracy and speed that are critical in the targeted real-time quality measurement system. digital.library.unt.edu/ark:/67531/metadc283843/
Ability of Offenders with Psychopathic Traits to Simulate Cognitive and Affective Empathy
The accurate assessment of psychopathy constitutes a critical component of forensic assessments addressing offender populations. Among the core characteristics of psychopathy, the interpersonal component of deception and empathic deficits are prominently observed in offenders with psychopathic traits. Given the negative consequences of being classified as a psychopath, offenders may be likely to minimize their psychopathic traits. In particular, no research has investigated whether offenders with psychopathic traits are able to simulate empathy in an effort to mask their cognitive or affective empathy deficits (e.g., lack of remorse about offenses). The present study aims to contribute to the literature with regard to the simulation of empathy. Using a mixed between- and within-subjects design, 81 male detainees were placed into (a) a low psychopathy group, (b) a moderate psychopathy group, or (c) a high psychopathy group based on the Psychopathy Checklist – Revised. For the within-subjects component, all offenders answered empathy questionnaires under genuine and simulation conditions. Results indicate the sample possessed cognitive empathy, but did not display affective empathy under genuine instructions. Under simulation instructions, participants significantly increased their scores on several empathy measures. The implications of simulated empathy and comparisons between groups regarding simulation abilities are discussed. digital.library.unt.edu/ark:/67531/metadc283859/
Challenge the Silence
Access: Use of this item is restricted to the UNT Community.
This collection of personal essays about incest, abuse, and depression explores the lasting effects of an invisible childhood. The essays follow the protagonist from the age of five to her early twenties. Her brother, at a young age, becomes sexually abusive of her and her sisters, and her parents fail to protect their daughters. The family is divided as the older girls strive to defend their little sisters, while their parents attempt to excuse their son. When her brother is finally sent away, the protagonist is left to salvage what remains of her relationships with her parents. digital.library.unt.edu/ark:/67531/metadc283840/
Finding Terroir in Southwest Iowa
Terroir combines the physical landscape of the vineyard with the grapevines and the methods and techniques used to produce wine from the grapes. This study used a GIS to identify the characteristics of the physical landscape in Pottawattamie, Mills, Montgomery, Fremont, and Page counties in southwestern Iowa. The components were combined in the GIS using a weighted linear index to identify areas suitable for vineyard development and to identify the general characteristics of the area. Vineyard owners were interviewed to help determine the weighting system to use in the GIS and to determine their perceptions of how the physical landscape impacts their vineyards, as well as to determine what grape varieties they plant in their vineyards and their decisions on making wine from these grapes. This information was collected to identify whether the vineyard owners had developed a sense of place for their vineyards and how this sense might aid them in the development of a terroir for their wines. The resulting perceptions about the individual wineries were then considered in conjunction with the results from the GIS modeling to understand how the physical landscape influences the concepts of sense of place and terroir in southwest Iowa. The physical landscape of southwest Iowa was fairly uniform, as were the grape varietals planted in the vineyards. This created a measure of similarity among the wineries, while individuality between wineries was then created by the wine-makers as they used different techniques to produce wine from the grapes. This allows each winery to develop a sense of place, yet be part of a larger sense of place that encompasses multiple wineries within the area. digital.library.unt.edu/ark:/67531/metadc283815/
Examining the Role of Latitude and Differential Insolation in Asymmetrical Valley Development
Valley development through erosional processes typically tends to create symmetrical valleys. Over time, water cuts through the substrate to create valleys, gorges, and canyons for which the sides are the valley are evenly sloped. However, there are anomalies to this process. Asymmetrical valleys have been well-documented even in areas of uniform substrate or little tectonic uplift. One proposed explanation for the asymmetry of these valleys is differential insolation. This may lead to different microclimates from one slope to another which alter the rate and extent of erosion. Since the differences in received insolation vary with latitude (especially in streams that flow along an east/west axis), it follows that the degree of asymmetry should also vary with latitude if differential insolation is a primary driving factor in the development of these valleys. To evaluate if insolation plays a role in the development of asymmetrical valleys, this study examines variability in asymmetry across 447 valleys in nine study areas located at different latitudes. The degree of asymmetry for each valley was measured by using 30 meter resolution digital elevation models (DEMs) to determine the slope angle of each side of the valley. Asymmetry was measured by computing a ratio of the average slope angle for each side of the valley (larger value divided by smaller). If the resulting value is one, the valley is deemed symmetrical. As the value increases, the degree of asymmetry increases. This investigation found that contrary to expectations, valleys at lower latitudes tend to have a higher degree of asymmetry than those at higher latitudes, which suggests that differential insolation does not play a major role in the development of these valleys. Instead, this study found that high altitudes and low latitudes are more frequently associated with a higher degree of asymmetry. These unexpected findings open the door to new avenues of investigation into the causes of asymmetrical valley development. digital.library.unt.edu/ark:/67531/metadc283821/
Hispanic Representation in the Superintendency: Perceived Competencies and Organizational Outcomes That Benefit School Districts
This study assessed 40 factors often cited in literature to determine the extent that Hispanic superintendents perceive them as influential when accessing the superintendency. Eight Hispanic superintendents in Texas participated in this qualitative study, which was based on interviews as well as written responses to a survey. This study found that the factors considered most influential to these superintendents were their ability to communicate, self-perception/self-efficacy, and level of overall preparedness. These findings contrast with previous research indicating that race or ethnicity, mentoring, and career path are most influential. The study also identified factors related to race and ethnicity that most influenced a Hispanic's ability to access the superintendency, albeit to a lesser degree. These factors were the ability to serve as a Hispanic role model to students, ability to increase Hispanic students' academic performance, and the ability to speak a second language. Moreover, through analysis of a large number of survey responses the study examined the extent to which a superintendent's race or ethnicity is significant to addressing the needs of Hispanics. To assure this question a comparative analysis of Hispanics' and non-Hispanics competencies and organizational outcome was conducted. The results indicate that superintendents, in general, regardless of race or ethnicity, can acquire knowledge about the Hispanic culture, develop cultural competence, and produce outcomes that affect Hispanics. A Hispanic, however, who possesses the ability to speak Spanish and has authentic cultural experiences, can potentially provide unique competencies in serving Hispanics. Cultural competence with Hispanics, however, does not supersede the importance of a superintendent's overall effectiveness and ability to meet the needs of all students. Whereas other studies have addressed the significance of cultural competency in other institutions that serve the public, such as the healthcare industry, this study addressed cultural competency in public education. Progressive definitions of cultural competency included the extent to which outcomes met constituent needs for measuring cultural competency. The overall findings in this study suggest a need to develop preparation programs that result in culturally competent leaders, a need to revise state required certification requirements to reflect a need for cultural competence, and a need to revise locally-developed job postings/descriptions to indicate that the superintendent must provide culturally competent leadership. digital.library.unt.edu/ark:/67531/metadc283806/
Repetition and Difference: Parodic Narration in Kander and Ebb's "The Scottsboro Boys"
The American musical team John Kander and Fred Ebb created many celebrated works, yet musicologists have carried out little research on those works. This study examines the role of music in the parodic narration of Kander and Ebb's final collaboration, The Scottsboro Boys. Kander and Ebb use minstrelsy to tell the story of the historic Scottsboro Boys trials with actors portraying the Scottsboro Boys as minstrels; at the same time, they employ a number of devices to subvert minstrelsy stereotypes and thereby comment on racism. Drawing on African American literary theory, sociolinguistics, and Bakhtin's dialogism, this study illuminates how Signifyin(g), a rhetorical tradition used to encode messages in some African American communities, is the primary way the actors playing the Scottsboro Boys subvert through minstrelsy. This study not only contributes to the discussion of Signifyin(g) in African American musicals and theatre as a tool of subversion, but also provides an example of non-African American creators—Kander and Ebb—using Signifyin(g) devices. They use these in the music and the book; in particular, Kander and Ebb do some Signifyin(g) on Stephen Foster's plantation melodies. digital.library.unt.edu/ark:/67531/metadc283804/
Metabolic Engineering in Plants to Control Source/sink Relationship and Biomass Distribution
Traditional methods like pruning and breeding have historically been used in crop production to divert photoassimilates to harvested organs, but molecular biotechnology is now poised to significantly increase yield by manipulating resource partitioning. It was hypothesized that metabolic engineering in targeted sink tissues can favor resource partitioning to increase harvest. Raffinose Family Oligosaccharides (RFOs) are naturally occurring oligosaccharides that are widespread in plants and are responsible for carbon transport, storage and protection against cold and drought stress. Transgenic plants (GRS47, GRS63) were engineered to generate and transport more RFOs through the phloem than the wild type plants. The transgenic lines produced more RFOs and the RFOs were also detected in their phloem exudates. But the 14CO2 labeling and subsequent thin layer chromatography analysis showed that the RFOs were most likely sequestered in an inactive pool and accumulate over time. Crossing GRS47 and GRS63 lines with MIPS1 plants (that produces more myo-inositol, a substrate in the RFO biosynthetic pathway) did not significantly increase the RFOs in the crossed lines. For future manipulation of RFO degradation in sink organs, the roles of the endogenous α-galactosidases were analyzed. The alkaline α-galactosidases (AtSIP1 and AtSIP2 in Arabidopsis) are most likely responsible for digesting RFOs in the cytoplasm and may influence the ability to manipulate RFO levels in engineered plants. Atsip1/2 (AtSIP1/AtSIP2 double-knockout plants) were generated and phenotypically characterized based on seed germination patterns, flowering time, and sugar content to observe the impact on RFO sugar levels. The observations and analysis from these lines provide a basis for further insight in the manipulation of resource allocation between source and sink tissues in plants for future research. digital.library.unt.edu/ark:/67531/metadc283836/
The Role of Attachment in Perceptions of Interparental Conflict and Behavior Problems in Middle Childhood
The current study investigated the association of interparental conflict, parent-child attachment, and children's behavior problems in middle childhood. Although the effects of interparental conflict have been studied extensively, there has been little research done in the developmental period of middle childhood. This study examined the potential mediating role of the attachment relationship between parents and children in a community sample consisting of 86 two-parent families with at least one child between the ages of 8-11. Path modeling procedures indicated that attachment security serves as a mediator between interparental conflict and child behavior problems based on child reports. In particular, child-reported attachment security to the mother significantly mediated the association between children's perceptions of threat from interparental conflict and child-reported internalizing and inattentive/hyperactive symptoms. Child-reported attachment security to the father was not a significant mediator and mediation was not supported in parent-report models. The current findings have implications for families experiencing conflict and speak to the importance of attachment in the parent-child relationship when explaining the association between instances of interparental conflict and child behavioral outcomes. In particular, parents who engage in conflict can prevent the damaging effects of that conflict by making the conflict less overt, explaining to children the reasons for the conflict, and providing children with some assurance that a secure parent-child and interparental relationship is still present, despite the conflict. digital.library.unt.edu/ark:/67531/metadc283822/
The Enemy of My Enemy Is What, Exactly? the British Flanders Expedition of 1793 and Coalition Diplomacy
Access: Use of this item is restricted to the UNT Community.
The British entered the War of the First Coalition against Revolutionary France in 1793 diplomatically isolated and militarily unprepared for a major war. Nonetheless, a French attack on the Dutch Republic in February 1793 forced the British to dispatch a small expeditionary force to defend their ally. Throughout the Flanders campaign of 1793, the British expeditionary force served London as a tool to end British isolation and enlist Austrian commitment to securing British war objectives. The 1793 Flanders campaign and the Allied war effort in general have received little attention from historians, and they generally receive dismissive condemnation in general histories of the French Revolutionary Wars. This thesis examines the British participation in the 1793 Flanders campaign a broader diplomatic context through the published correspondence of relevant Allied military and political leaders. Traditional accounts of this campaign present a narrative of defeat and condemn the Allies for their failure to achieve in 1793 the accomplishments of the sixth coalition twenty years later. Such a perspective obscures a clear understanding of the reasons for Allied actions. This thesis seeks to correct this distortion by critically analyzing the relationship between British diplomacy within the Coalition and operations in Flanders. Unable to achieve victory on their own strength, the British used their expeditionary force in Flanders as diplomatic leverage to impose their objectives on the other powers at war with France. digital.library.unt.edu/ark:/67531/metadc283820/
An Examination of the Similarities and Differences Between Transformational and Authentic Leadership and Their Relationship to Followers' Outcomes
To date there is no comprehensive understanding of what leadership is, nor is there an agreement among different theorists on what a good or effective leader should be. The purpose of this dissertation is to examine the theoretical and empirical similarities and differences of two styles of leadership – transformational and authentic leadership. Follower outcomes, as well as, the effects of trust and psychological capital within these paradigms are of particular interest. Although theoretical differences are proposed for the leadership style, the extent of overlap suggests the need to more closely examine each theory. Pilot studies were created to validate original scenarios created for the study as well as to examine the validity and reliability of new measurement instruments. The dissertation is designed to determine whether the relationships between authentic leadership and a variety of follower outcomes including performance, affective commitment, satisfaction, trust, and organizational citizenship behavior are similar to those between transformational leadership and these outcomes. In addition, variables more unique to authentic leadership research including psychological capital and follower well-being were examined within both paradigms to determine whether their relationships are similar to each type of leadership style. An experimental study using Qualtrics was used to collect the data with the expectation that there would be significant differences in the two styles of leadership such that each explains unique variance in follower behavior. The results of this dissertation support the lack of perceptual difference between the two theories of leadership. The results of this experiment do not come completely unexpected because of the ethical overlap between the two styles of leadership. Although subjects in the experiment could differentiate authentic leadership from transformational leadership based on the manipulations, authentic leadership effects were not significantly different when compared to transformational leadership effects. As a result, analyses in my research do not support previous theoretical development of authentic leadership as a separate theory from transformational leadership. Consequently, lack of support for my hypotheses actually provides valuable information to the study of leadership and calls into question the continued pursuit of research on authentic leadership. Although this dissertation was constructed to investigate the differences between authentic leadership and transformational leadership relative to follower outcomes, results found for gender differences may highlight an additional component to these leadership paradigms not previously considered. digital.library.unt.edu/ark:/67531/metadc283823/
Mist and Microstructure Characterization in End Milling Aisi 1018 Steel Using Microlubrication
Flood cooling is primarily used to cool and lubricate the cutting tool and workpiece interface during a machining process. But the adverse health effects caused by the use of flood coolants are drawing manufacturers' attention to develop methods for controlling occupational exposure to cutting fluids. Microlubrication serves as an alternative to flood cooling by reducing the volume of cutting fluid used in the machining process. Microlubrication minimizes the exposure of metal working fluids to the machining operators leading to an economical, safer and healthy workplace environment. In this dissertation, a vegetable based lubricant is used to conduct mist, microstructure and wear analyses during end milling AISI 1018 steel using microlubrication. A two-flute solid carbide cutting tool was used with varying cutting speed and feed rate levels with a constant depth of cut. A full factorial experiment with Multivariate Analysis of Variance (MANOVA) was conducted and regression models were generated along with parameter optimization for the flank wear, aerosol mass concentration and the aerosol particle size. MANOVA indicated that the speed and feed variables main effects are significant, but the interaction of (speed*feed) was not significant at 95% confidence level. The model was able to predict 69.44%, 68.06% and 42.90% of the variation in the data for both the flank wear side 1 and 2 and aerosol mass concentration, respectively. An adequate signal-to-noise precision ratio more than 4 was obtained for the models, indicating adequate signal to use the model as a predictor for both the flank wear sides and aerosol mass concentration. The highest average mass concentration of 8.32 mg/m3 was realized using cutting speed of 80 Surface feet per minute (SFM) and a feed rate of 0.003 Inches per tooth (IPT). The lowest average mass concentration of 5.91 mg/m3 was realized using treatment 120 SFM and 0.005 IPT. The cutting performance under microlubrication is five times better in terms of tool life and two times better in terms of materials removal volume under low cutting speed and feed rate combination as compared to high cutting speed and feed rate combination. Abrasion was the dominant wear mechanism for all the cutting tools under consideration. Other than abrasion, sliding adhesive wear of the workpiece materials was also observed. The scanning electron microscope investigation of the used cutting tools revealed micro-fatigue cracks, welded micro-chips and unusual built-up edges on the cutting tools flank and rake side. Higher tool life was observed in the lowest cutting speed and feed rate combination. Transmission electron microscopy analysis at failure for the treatment 120 SFM and 0.005 IPT helped to quantify the dislocation densities. Electron backscatter diffraction (EBSD) identified 4 to 8 µm grain size growth on the machined surface due to residual stresses that are the driving force for the grain boundaries motion to reduce its overall energy resulting in the slight grain growth. EBSD also showed that (001) textured ferrite grains before machining exhibited randomly orientated grains after machining. The study shows that with a proper selection of the cutting parameters, it is possible to obtain higher tool life in end milling under microlubrication. But more scientific studies are needed to lower the mass concentration of the aerosol particles, below the recommended value of 5 mg/m3 established by Occupational Safety and Health Administration (OSHA). digital.library.unt.edu/ark:/67531/metadc283858/
Quantifying Forest Vertical Structure to Determine Bird Habitat Quality in the Greenbelt Corridor, Denton, Tx
This study presents the integration of light detection and range (LiDAR) and hyperspectral remote sensing to create a three-dimensional bird habitat map in the Greenbelt Corridor of the Elm Fork of the Trinity River. This map permits to examine the relationship between forest stand structure, landscape heterogeneity, and bird community composition. A biannual bird census was conducted at this site during the breeding seasons of 2009 and 2010. Census data combined with the three-dimensional map suggest that local breeding bird abundance, community structure, and spatial distribution patterns are highly influenced by vertical heterogeneity of vegetation surface. For local breeding birds, vertical heterogeneity of canopy surface within stands, connectivity to adjacent forest patches, largest forest patch index, and habitat (vegetation) types proved to be the most influential factors to determine bird community assemblages. Results also highlight the critical role of secondary forests to increase functional connectivity of forest patches. Overall, three-dimensional habitat descriptions derived from integrated LiDAR and hyperspectral data serve as a powerful bird conservation tool that shows how the distribution of bird species relates to forest composition and structure at various scales. digital.library.unt.edu/ark:/67531/metadc283803/
Altruism and Depression: Exploring This Relationship and the Mechanisms Behind It
The impact of environmental influences on depression has been well established by research. In particular, it is known that receiving/perceiving adequate social support has a protective influence on depression. Less is known about the protective benefits of providing support to others, namely in the form of altruistic, empathetic, or prosocial behavior. While research has shown that having altruistic attitudes and engaging in altruistic behaviors has a positive impact on physical health and mental well-being, studies on the association between altruistic attitudes and/or behavior and depression are limited. The present study examined the relationship between altruism and depression, and hypotheses were tested that allow for explanation of why altruism may protect against depression. A sample of 303 participants was recruited from the University of North Texas and the surrounding community. Participants completed an online survey that examined their altruistic activities, details regarding these activities, their prosocial attitudes, and their current level of depression. Results did not support that level of involvement in altruistic activities is directly related to depression severity. However, outcomes from involvement in altruistic activities, including sense of overburden from participating in altruistic activities, level of social interaction with other helpers and those helped during altruistic activities, and sense of life satisfaction and purpose gained from participating in altruistic activities, were significantly related to depression severity. These results suggest that participating in altruistic activities that are not perceived as overburdening may lead to outcomes that could positively impact depression. Limitations and directions for future research are discussed. digital.library.unt.edu/ark:/67531/metadc283819/
A Survey of the Solo and Chamber Works for Trumpet, Horn, Trombone, Euphonium and Tuba By the Hungarian Composer Frigyes Hidas
Hidas composed more than 135 compositions. Of these 135 compositions 67 feature the trumpet, horn, trombone, euphonium, and tuba in a solo setting, a homogenous chamber setting, or a heterogeneous chamber setting. The first section of this project presents the significance of the topic, state of research, and methodology. Chapter one provides a narrative detailing the collaboration of Hidas with Gusztáv Höna and László Szabó, Sr. Chapter two provides a brief description of characteristics found in Hidas' compositions. Appendix A and B provides a survey of the 67 works for brass instruments that Hidas composed. Included in this survey is information pertaining to the title, editor, publisher and date of publication, total measures, duration, ranges, degree of difficulty, clefs, special effects/techniques, instrumentation, dedications, analytical information, general comments, recordings, and rental details. digital.library.unt.edu/ark:/67531/metadc283827/
Resilience Among Middle School Students
Resilience is the ability to survive and persevere during difficult times. Resilient people also thrive after overcoming adversity. Adolescents have many developmental tasks to overcome in their quest to becoming adults. Difficulty with these tasks can lead to academic and personal failures. Adolescents with low resilience often struggle with low self-esteem. If students are identified early as having lower levels of resilience, professional school counselors have an opportunity to provide resilience-enhancing activities. Prior to middle school, students are assigned all of their classes. During middle school, students begin to select their elective courses which may be representative of their interests and current emotional status. By looking at students' elective courses, I looked for patterns of resilience that may help professional school counselors proactively identify students in need of additional guidance in order to be academically successful. This study utilized a convenience sample of middle school students enrolled in the 8th grade (N = 190) of a large suburban school district located in the southwest United States to measure levels of resilience and elective course enrollment. Gender of the participants was 107 females and 83 males. The students reported their ethnicity as 5.8% African American/Black, 11.1% Asian, 12.6% Hispanic, 1.1% Native American, 1.6% Pacific Islander, 59.5% Caucasian/White, and 8.4% multiracial. I measured resilience in this study using the Resilience Scale and comparisons based on elective course. Data analyses include descriptive statistics and ANOVAs. Based on a statistical significance criterion of p < .05, students enrolled in athletics scored significantly higher in resilience than did non-athletics students enrolled in physical education/outdoor education (p = .035). Additionally, Caucasian females were significantly less resilient than Caucasian males (p = .031). Limitations of the study, implications of the results for practice, and recommendations for future research are presented. digital.library.unt.edu/ark:/67531/metadc283857/
Investigation of an Investment Casting Method Combined with Additive Manufacturing Methods for Manufacturing Lattice Structures
Cellular metals exhibit combinations of mechanical, thermal and acoustic properties that provide opportunities for various implementations and applications; light weight aerospace and automobile structures, impact and noise absorption, heat dissipation, and heat exchange. Engineered cell topologies enable one to control mechanical, thermal, and acoustic properties of the gross cell structures. A possible way to manufacture complex 3D metallic cellular solids for mass production with a relatively low cost, the investment casting (IC) method may be used by combining the rapid prototyping (RP) of wax or injection molding. In spite of its potential to produce mass products of various 3D cellular metals, the method is known to have significant casting porosity as a consequence of the complex cellular topology which makes continuous fluid's access to the solidification interface difficult. The effects of temperature on the viscosity of the fluids were studied. A comparative cost analysis between AM-IC and additive manufacturing methods is carried out. In order to manufacture 3D cellular metals with various topologies for multi-functional applications, the casting porosity should be resolved. In this study, the relations between casting porosity and processing conditions of molten metals while interconnecting with complex cellular geometries are investigated. Temperature, and pressure conditions on the rapid prototyping – investment casting (RP-IC) method are reported, thermal stresses induced are also studied. The manufactured samples are compared with those made by additive manufacturing methods. digital.library.unt.edu/ark:/67531/metadc283786/
Face-to-face Versus Online Gender Roles: the Effect of Psychological Identity on the Characteristics and Circumstances of Online Disinhibition
Human behaviors and social norms are transferred to the Internet in complex and divergent ways. The term online disinhibition has been coined to describe situations when Internet users seem to behave more openly and unrestrained online, often acting in ways they would not dare to act in the face-to-face world. According to Suler, there is a need for future research to "focus on which people, under what circumstances, are more predisposed to the various elements of online disinhibition." With this in mind, this descriptive study sought to determine whether or not people are more true to their authentic psychological identities (i.e., genders) during online interaction or create completely new identities because of the more permissive social norms created by cyberspace. Through video recorded face-to-face discussions, reflective online discussions, open-ended online surveys, and semi-structured interviews, qualitative data was collected for analysis. The results and findings demonstrated that some personality traits are magnified during online interaction, but individuals ultimately stay true to their established gender roles. digital.library.unt.edu/ark:/67531/metadc283788/
Mutual Influences in Romantic Attachment, Religious Coping, and Marital Adjustment
This study examined associations among romantic attachment anxiety and avoidance, positive and negative religious coping, and marital adjustment in a community sample of 81 heterosexual couples. Both spouses completed the Experiences in Close Relationships Scale (ECR), a brief measure of religious coping (Brief RCOPE), the Dyadic Adjustment Scale (DAS), and a demographic questionnaire as part of a larger study. Multilevel modeling (MLM) for the actor-partner interdependence model (APIM) was used. Attachment avoidance was inversely related to positive religious coping. In contrast, attachment anxiety was directly related to negative religious coping. Positive religious coping buffered the relationship between attachment avoidance and marital adjustment. In contrast, attachment anxiety was detrimental to marital adjustment regardless of positive religious coping, and positive religious coping was related to higher marital adjustment only in the context of low attachment anxiety. Surprisingly, the spouse's attachment anxiety was inversely related to the respondent's marital adjustment only when the respondent reported low levels of negative religious coping, whereas in the context of high negative religious coping, the partner's attachment anxiety was related to higher marital adjustment. Results support using attachment theory to conceptualize religious coping and the consideration of both attachment and religious coping constructs in counseling. digital.library.unt.edu/ark:/67531/metadc283784/
Mechanics and Mechanisms of Creep and Ductile Fracture
The main aim of this dissertation is to relate measurable and hopefully controllable features of a material's microstructure to its observed failure modes to provide a basis for designing better materials. The understanding of creep in materials used at high temperatures is of prime engineering importance. Single crystal Ni-based superalloys used in turbine aerofoils of jet engines are exposed to long dwell times at very high temperatures. In contrast to current theories, creep tests on Ni-based superalloy specimens have shown size dependent creep response termed as the thickness debit effect. To investigate the mechanism of the thickness debit effect, isothermal creep tests were performed on uncoated Ni-based single crystal superalloy sheet specimens with two thicknesses and under two test conditions: a low temperature high stress condition and a high temperature low stress condition. At the high temperature, surface oxidation induced microstructural changes near the free surface forming a layered microstructure. Finite element calculations showed that this layered microstructure gave rise to local changes in the stress state. The specimens also contained nonuniform distribution of initial voids formed during the solidification and homogenization processes. The experiments showed that porosity evolution could play a significant role in the thickness debit effect. This motivated a basic mechanics study of porosity evolution in single crystals subjected to creep for a range of stress states. The study was performed using three-dimensional finite deformation finite element analysis of unit cells containing a single initially spherical void in a single crystal matrix. The materials are characterized by a rate-dependent crystal plasticity constitutive relation accounting for both primary and secondary creep. The effect of initial void spacing and creep exponent was also explored. Based on the experimental observations and results of finite element calculations a quantitative mechanistic model is proposed that can account for both bulk and surface damage effects and assess their relative roles in the observed thickness debit effect. Another set of calculations aim at relating the crack growth resistance and fracture surface morphology to material microstructure for ductile structural metals. The process that governs the ductile fracture of structural materials at room temperature is one of nucleation, growth and coalescence of micron scale voids, and involves large plastic deformations. Experimental studies have shown that fracture surfaces in a wide variety of materials and under a wide variety of loading conditions have remarkable scaling properties. For thirty years, the hope to relate the statistical characterization of fracture surfaces to a measure of a material's crack growth resistance has remained unfulfilled. Only recently has the capability been developed to calculate sufficient amounts of three dimensional ductile crack growth in heterogeneous microstructures to obtain a statistical characterization of the predicted fracture surfaces. This development has enabled the exploration of the relation of both fracture toughness and fracture surface statistics to material properties and microstructure when the fracture mechanism is one of void nucleation, growth and coalescence. The relation of both toughness and the statistical properties of fracture surfaces in calculations of heterogeneous microstructures to various microstructural features is discussed and a remarkable correlation between fracture surface roughness and fracture toughness is shown for the first time. digital.library.unt.edu/ark:/67531/metadc283799/
The Phantom Menace: the F-4 in Air Combat in Vietnam
The F-4 Phantom II was the United States' primary air superiority fighter aircraft during the Vietnam War. This airplane epitomized American airpower doctrine during the early Cold War, which diminished the role of air-to-air combat and the air superiority mission. As a result, the F-4 struggled against the Soviet MiG fighters used by the North Vietnamese Air Force. By the end of the Rolling Thunder bombing campaign in 1968, the Phantom traded kills with MiGs at a nearly one-to-one ratio, the worst air combat performance in American history. The aircraft also regularly failed to protect American bombing formations from MiG attacks. A bombing halt from 1968 to 1972 provided a chance for American planners to evaluate their performance and make changes. The Navy began training pilots specifically for air combat, creating the Navy Fighter Weapons School known as "Top Gun" for this purpose. The Air Force instead focused on technological innovation and upgrades to their equipment. The resumption of bombing and air combat in the 1972 Linebacker campaigns proved that the Navy's training practices were effective, while the Air Force's technology changes were not, with kill ratios becoming worse. However, the last three months of the campaign introduced an American ground radar system that proved more effective than Top Gun in improving air-to-air combat performance. By the end of the Vietnam War, the Air Force and Navy overcame the inherent problems with the Phantom, which were mostly of their own making. digital.library.unt.edu/ark:/67531/metadc283785/
Student Experiences and Expectations Related to the Vertical Transfer Process From Two Feeder Community Colleges of a Senior Institution
The purpose of this study was to understand the experiences and expectations of community college students attending Temple College and Central Texas College regarding what they may expect as part of the vertical transfer process in order to improve the likelihood of their persistence to graduation at Texas A&M University-Central Texas (TAMUCT). The target population was approximately 700 students enrolled in two feeder Texas community colleges who had expressed intent to transfer to TAMUCT. The response rate was 19%, and 136 useable surveys were used for analysis. The sample was 74% female, 45% White with the majority minority. To assess the relationships between community college experiences and transfer expectation variables, correlations and logistic regression were used. No linear relationships were found regarding gender, age, ethnicity, highest level of parents' education, the aspirational variables of highest academic degree intend to obtain at any college or university and at TAMUCT, and the feeder community college attended and the two scales. A statistically significant relationship was found between parental income level and reported community college experiences (F(4, 79) = 2.612, p = .042) and vertical transfer expectations (F(4, 52) = 3.318, p = .017). Community college students from lower socioeconomic backgrounds may utilize the community college to upper-level institution vertical transfer pathway as a way to obtain an affordable baccalaureate degree. Community colleges and university administrators need to continue working together to establish unique and creative ways to create seamless transitions for vertical transfer students utilizing the community college to upper-level institution pathway to degree completion. digital.library.unt.edu/ark:/67531/metadc283801/
Glucose As an Energy Source to Increase Self-control in Restrained Eaters
Research evidence is suggestive of a strength model of self-control, also known as ego depletion, in social psychological literature. Engaging in an initial task of self-control depletes a limited resource, resulting in less self-control on a subsequent, unrelated task. The strength model of self-control has been applied to many practical, everyday situations, such as eating behaviors among dieters. Newer studies suggest that blood glucose is the resource consumed during acts of self-control. Consuming glucose seems to "replete" individuals who have been depleted, improving performance and self-control. The current study aimed to examine the effects of ego-depletion on restrained eaters. The hypothesis was that restrained eaters who were depleted by a task of self-control would exhibit more disinhibition on a taste-test task than would restrained eaters who were not depleted. However, if the participants were given glucose following the depletion task, then their self-control would be "repleted" and they would exhibit similar control to that of the non-depleted participants. Contrary to expectations there were no differences between the groups in terms of total amount of cookies consumed. These results are inconsistent with a glucose model of self-control. Suggestions for future research and implications of the findings are discussed. digital.library.unt.edu/ark:/67531/metadc283842/
Values and Valuing in a College Population
Values and valuing behavior have many conceptualizations. Despite how they are defined, values have a significant impact on behavior and are idiosyncratic in nature. The present study reviewed values research and sought to explore values identification and successful valued living among an archived sample of university students. Specifically, in a convenience sample of 282 undergraduate students, variables that affect values identification and behavior such as ethnicity, gender, psychological distress, and psychological flexibility were identified. Results indicated that university students identified with more than one valued living domain (as measured by the PVQ) and that contextual factors such as ethnicity, gender, age, and religiosity/spirituality were associated with specific values endorsed. Furthermore, psychological distress, including depression and anxiety (as measured by the DASS) was negatively correlated with values purity – the extent to which values are freely chosen. Finally, psychological flexibility (low experiential avoidance as measured by the AAQ-2), predicted values purity and successful living in accordance with identified values, and the relationship between these two variables was mediated by psychological flexibility. digital.library.unt.edu/ark:/67531/metadc283808/
Design and Application of Phased Array System
Since its invention, phased array has been extensively applied in both military and civil areas. The applications include target detecting and tracking, space probe communication, broadcasting, human-machine interfaces, and remote sensing. Although the phased array applications show a broad range of potential market, there are some limitations of phased array's development: high cost, complex structure, narrow bandwidth, and high power consumption. Therefore, novel ideas are needed to reduce these constraints. In this thesis, several new approaches about the design and application of phased array are presents. First, the principle of phased array and fundamental design equations are introduced. Second, a new application of phased array antenna for radar respiration measurement is presented. By integrating a 4×4 Butler matrix with four-element antenna array, there will be four distinct main beams in radiation pattern. This new approach can improve the measurement accuracy and realize a high detecting rate. Third, a compact phased array antenna system based on dual-band operations is introduced. Dual-band function can make N-antenna system obtain 2N unique radiation beams (N is an integer) and achieve a significant size reduction compared to the conventional single-band system. To verify the design concept, a four-element phased array antenna working at 5GHz and 8GHz is designed and fabricated. The measurement results make a good agreement with the simulations. Finally, a novel architecture of steering phase feeding network by using bi-directional series-fed topology is presented. This bi-directional series-fed network needs less phase shifters and realizes steering phase function by applying control voltage. digital.library.unt.edu/ark:/67531/metadc283830/
An Investigation of the Phase Model of Psychotherapy Across Therapeutic Orientations: Are Different Approaches Actually All That Different?
The current study investigated the process of change underlying two different evidence-based treatments that yield similar outcome effectiveness in the treatment of depression: Cognitive Therapy (CT) and Interpersonal Therapy (IPT). The phase model of psychotherapeutic change (Howard et al., 1993) change is used to provide both a theoretical and practical framework in which to assess different patterns of change across the treatment modalities. The phase model posits that recovery from distress occurs in three sequential stages: remoralization, remediation and rehabilitation. CT can be conceptualized as a treatment in which the primary focus is on the treatment of symptoms (remediation), whereas IPT can typically be conceptualized as focusing on interpersonal conflicts and functioning (rehabilitation). The study utilized the TDCRP dataset (Elkin et al., 1985). Survival analysis indicated no significant difference in terms of onset or pattern of improvement across treatment orientations. Chi square analyses indicated individuals treated with IPT spend significantly more time engaged in rehabilitation compared to their CT counterparts. Taken together, these findings represent evidence that the process of therapeutic change is similar, if not virtually identical, across therapeutic orientation. The analyses also indicate that the phases of therapy may not necessarily be mutually exclusive and sequential, but may instead represent co-occurring patterns of improvement which are not sequentially determined. digital.library.unt.edu/ark:/67531/metadc283862/
Development of Novel Semi-conducting Ortho-carborane Based Polymer Films: Enhanced Electronic and Chemical Properties
A novel class of semi-conducting ortho-carborane (B10C2H12) based polymer films with enhanced electronic and chemical properties has been developed. The novel films are formed from electron-beam cross-linking of condensed B10C2H12 and B10C2H12 co-condensed with aromatic linking units (Y) (Y=1,4-diaminobenzene (DAB), benzene (BNZ) and pyridine (PY)) at 110 K. The bonding and electronic properties of the novel films were investigated using X-ray photoelectron spectroscopy (XPS), UV photoelectron spectroscopy (UPS) and Mulliken charge analysis using density functional theory (DFT). These films exhibit site-specific cross-linking with bonding, in the pure B10C2HX films, occurring at B sites non-adjacent to C in the B10C2H12 icosahedra. The B10C2H12:Y films exhibit the same phenomena, with cross-linking that creates bonds primarily between B sites non-adjacent to C in the B10C2H12 icosahedra to C sites in the Y linking units. These novel B10C2HX: Y linked films exhibit significantly different electron structure when compared to pure B10C2HX films as seen in the UPS spectra. The valence band maxima (VBM) shift from - 4.3 eV below the Fermi level for pure B10C2HX to -2.6, -2.2, and -1.7 for B10C2HX:BNZ, B10C2HX:PY, and B10C2HX:DAB, respectively. The top of the valence band is composed of states derived primarily from the Y linking units, suggesting that the bottom of the conduction band is composed of states primarily from B10C2H12. Consequently these B10C2HX:Y films may exhibit longer electron-hole separation lifetimes as compared to pure B10C2HX films. This research should lead to an enhancement of boron carbide based neutron detectors, and is of potential significance for microelectronics, spintronics and photo-catalysis. digital.library.unt.edu/ark:/67531/metadc283826/
Military-diplomatic Adventurism: Communist China's Foreign Policy in the Early Stage of the Korean War (1950-1951)
The thesis studies the relations of Communist China's foreign policy and its military offensives in the battlefield in Korean Peninsula in late 1950 and early 1951, an important topic that has yet received little academic attention. As original research, this thesis cites extensively from newly declassified Soviet and Chinese archives, as well as American and UN sources. This paper finds that an adventurism dominated the thinking and decision-making of Communist leaders in Beijing and Moscow, who seriously underestimated the military capabilities and diplomatic leverages of the US-led West. The origin of this adventurism, this paper argues, lays in the CCP's civil war experience with their Nationalist adversaries, which featured a preference of mobile warfare over positional warfare, and an opportunist attitude on cease-fire. This adventurism ended only when Communist front line came to the verge of collapse in June 1951. digital.library.unt.edu/ark:/67531/metadc283814/
A Performer's Guide to Béla Bartók's Violin Concerto No 1, Opus Posthumous, 1907–1908
Despite Bartók's lasting international fame, some of his works remain unjustly lesser-known. One of the pieces that still resides in relative obscurity is his Violin Concerto No.1—a gem of the violin repertoire that must be brought to the broader public's attention. The fact that the concerto was hidden definitely contributed to its little–known status at first. However, the most important cause for the lack of enthusiasm to tackle this terrific work lies in the unorthodox demands it puts on the violinist. The purpose of this paper is to provide musical and technical suggestions based on Bartók's performing style and on his requirements for performer, which will help to create a more persuasive interpretation of the piece. The guide covers the questions of character, articulation, dynamics, and other performance aspects, and also provides practical suggestions, such as fingerings and bowings. It is hoped that this study will help violin performers to gain additional knowledge and insight into this composition and encourage more frequent performances of it. digital.library.unt.edu/ark:/67531/metadc283828/
Fear of Alzheimer's Disease in Middle to Late Adulthood: a Two Year Investigation of Change Versus Stability
The term dementia refers to a progressive decline in cognitive functioning resulting in a significant impairment in daily living. Given the devastating impacts of the disease and lack of a cure, it is reasonable to expect people fear developing a dementia. Alzheimer's disease ranks high among the most feared diseases in national samples of the American population. As a topic of study, little is known about the determinants of fear of Alzheimer's disease and how this fear may change as a function of aging, time, or experience. The current study sought to fill this gap by investigating the nature of changes in fear of Alzheimer's disease by following participants (N = 227) over the course of two years. Volunteers completed measures on fear of dementia, knowledge about Alzheimer's disease, knowledge about the aging process, personality traits, memory self-efficacy, anxiety about aging, and Alzheimer's-related experiences (i.e., family history, caregiving experience, number of people known with the disease, personal diagnosis, etc.). Results supported the notion that fear for becoming a burden to others, a component of fear of dementia, decreased over the two years. In addition, personality traits and memory self-efficacy mediated the two-year change in concerns about perceived symptoms of cognitive decline. In predicting fear for various aspects of Alzheimer's disease, anxiety about aging and experience/exposure to the disease emerged as prominent predictors. These results highlight dementia concerns and offer guidance for early interventions, such as an open communication with family and health care providers about fear of dementia. digital.library.unt.edu/ark:/67531/metadc283854/
Learning From Each Other: Narrative Explorations of Art Museum Self-guided Materials
By engaging in collaborative arts-based and arts-informed narrative inquiry with my six-year-old daughter, we explored self-guided materials in art museums in the North Texas area. Though the field of art museum education is becoming increasingly participatory, most academic research related to self-guided materials has fallen short of exploring visitors' experiences with these materials. Furthermore, the perspectives of children have been long overlooked in academic and, at times, institutional research about family experiences in museums. Over the course of nine months, my daughter and I visited art museums and engaged with their self-guided materials, ranging from audio tours to interactive galleries. During this time we created collaborative works of art based on our experiences, which acted as both data collection and analysis in preparation for writing narratives. Our narrative explorations allowed us each to better understand our collective experiences. Though this research specifically targets self-guided materials in art museums, any educator interested in intergenerational or collaborative family learning may find both our methodologies and our conclusions to be helpful in better understanding how narratives are essential to this type of learning. digital.library.unt.edu/ark:/67531/metadc283845/
Reliability of an On-line System to Assess Physical Activity Behaviors in an Active Group of Kinesiology Undergraduate Students
Engaging in muscle strengthening activities (MSA) as part of a physical activity program offers health benefits. Although the merits of physical activity are well documented, many adults fail to meet appropriate levels as recommended in the 2008 Physical Activity Guidelines for Americans (PAGA). To get a more complete understanding on an individual's physical activity behaviors, the Tracking Resistance Exercise and Strength Training (TREST) internet based survey was developed. The purpose of the current study was to determine the test-retest reliability of TREST items. Additionally, the prevalence of participants meeting the 2008 PAGA was reported by gender. The survey was completed approximately two weeks apart by 224 (52% male) undergraduate kinesiology students. Analysis of the survey items presented TREST as a reliable instrument in assessing an individual's physical activity behavior with a focus on MSA. Among the convenience sample of 445 participants (56% male) that completed the survey in assessment #1, 73% met the 2008 PAGA minimum recommendations for MSA (>=2 days/week) and aerobic activity (>= 150 min MVPA). A more complete MSA and MVPA criteria was established (requiring MSA of all seven major muscle groups) and only 32% of participants met this guideline. In general, men engaged in aerobic exercise and MSA more than women. These results cannot be generalized due the age, activity level, and education of the study's participants. Future studies should investigate the validity of TREST items among a sample of varying fitness levels, races/ethnicities, ages, and educational levels. digital.library.unt.edu/ark:/67531/metadc283847/
Central Office Administrators' Perceptions of the Professional Learning Community Process
This study provides a qualitative interpretation of the work done by central office administrators in a school district in Texas as they supported and built capacity for the professional learning community (PLC) process over a five year time period. Literature by PLC scholars, especially R. DuFour, R.B. DuFour, Eaker, Hord, Hipp, Huffman, and Olivier, informed development of the study. In a school district of 19,000 students and 2,000 staff members, ten central office administrators were interviewed to gain their perceptions of their roles in the PLC process. Interviews were analyzed through the processes of initial, focused, and theoretical coding. Documents were examined and used as supplemental sources of data to corroborate the perspectives provided. Findings revealed the story of central office administrators who worked interdependently to support and build capacity in the implementation and sustainment of the PLC process. A thick description of the work based on their perceptions offers actions and behaviors of administrators specific to their roles and practices and protocols developed to hold the work together. A grounded theory was developed with regard to central office administrators' support and capacity-building for the PLC process. From the administrators' perceptions, six theoretical categories relating to central office support and capacity building of the PLC process emerged: 1) establishment, 2) deployment, 3) accountability for implementation, 4) adult learning, 5) collaboration, and 6) leadership development. The study contributes an interpretivist description of the involvement of central office in the PLC process and confirms the importance of the change process in the implementation of the PLC framework. digital.library.unt.edu/ark:/67531/metadc283851/
The Useful Arts
Access: Use of this item is restricted to the UNT Community.
This creative nonfiction dissertation is a series of braided narratives that chronicle the author's career as a trombonist in the John Smith Ensemble. As an amateur trombonist, the author is shocked to be hired as a professional musician for an orchestra that plays on PBS and at Carnegie Hall. She quickly realizes, however, that the job requires her to play the trombone quietly in front of an unplugged microphone while a CD recording of another, more talented trombonist is blasted out toward an unknowing audience. The job also requires the author to tour around America. The scenes of from this tour are braided with scenes wherein she reflects on her life as a professional fake musician and her past failed attempts at getting a job. digital.library.unt.edu/ark:/67531/metadc283812/
A Relationship-based Cross National Customer Decision-making Model in the Service Industry
In 2012, the CIA World Fact Book showed that the service sector contributed about 76.6% and 51.4% of the 2010 gross national product of both the United States and Ghana, respectively. Research in the services area shows that a firm's success in today's competitive business environment is dependent upon its ability to deliver superior service quality. However, these studies have yet to address factors that influence customers to remain committed to a mass service in economically diverse countries. In addition, there is little research on established service quality measures pertaining to the mass service domain. This dissertation applies Rusbult's investment model of relationship commitment and examines its psychological impact on the commitment level of a customer towards a service in two economically diverse countries. In addition, service quality is conceptualized as a hierarchical construct in the mass service (banking) and specific dimensions are developed on which customers assess their quality evaluations. Using, PLS path modeling, a structural equation modeling approach to data analysis, service quality as a hierarchical third-order construct was found to have three primary dimensions and six sub-dimensions. The results also established that a country's national economy has a moderating effect on the relationship between service quality and investment size, and service satisfaction on investment size. This study is the first to conceptualize and use the hierarchical approach to service quality in mass services. Not only does this study build upon the investment model to provide a comprehensive decision model for service organizations to increase their return on investment but also, provides a congruence of work between service quality and the investment model in the management and decision sciences discipline. digital.library.unt.edu/ark:/67531/metadc283834/
The Effects of the Texas Reading First Response to Intervention Program on Student Achievement and Campus Special Education Rates
The purpose of this study was to examine special education populations, special education reading achievement, and regular education reading achievement in relation to the implementation of the Reading First three-tiered model as a response to Intervention platform. The population for this study focused on rural schools with Grades K-3 in attendance. Schools participated in the reading first grant period of the 2003-2009 school years. Forty-seven Texas Reading First schools were compared to 47 campuses having similar populations, socioeconomic makeups, and grade structures. This study utilized quantitative research measures to evaluate the level of special education populations on Reading First campuses using a response to intervention model. Quantitative measures were also used to evaluate those same campuses achievement rates of both special education and regular education students on the Texas Assessment of Knowledge and Skills reading tests. The study's outcome data showed little to no statistic significance for the three research questions. However, the inferential statistics showed a decrease in the special education population of the Reading First schools. Inferential statistics also indicated both the special education and the regular education students showed growth on the Texas Assessment of Knowledge and Skills reading tests. The use of a response to intervention program can be effective in the reduction of special education students identified on school campuses. Response to intervention programs can boost achievement levels of students receiving special education services. Students not enrolled in special education can benefit from effective response to intervention services. digital.library.unt.edu/ark:/67531/metadc283855/
Endocrine Disruption of Levonorgestrel in Early-life Stages of Fathead Minnows, Pimephales Promelas
Pharmaceuticals have routinely been detected in the environment resulting in a growing concern about whether these drugs could elicit effects on aquatic organisms. The concerns are centered on the highly conserved nature of mammalian therapeutic targets in fish. These pharmaceuticals are found at very low levels in the environment, which can result in sub-lethal effects in aquatic organisms. Therefore, 28 d early-life stage studies were conducted on six pharmaceuticals to assess their impacts on survival and growth fathead minnow larvae. Two pharmaceuticals tested, carbamazepine and fenofibrate, resulted in no alterations to survival and growth. However, amiodarone, clozapine, dexamethasone, and levonorgestrel (LNG) reduced survival at concentrations tested with LNG being the most potent at 462 ng/L. Survival was increased with amiodarone and clozapine; however LNG significantly decreased growth at 86 ng/L. Therefore, the most potent pharmaceutical tested was the synthetic progestin LNG with survival and growth impacts at concentrations less than 1 μg/L. Further analysis was conducted by measuring specific endocrine related mRNA transcript profiles in FHM larvae following the 28 d ELS exposure to LNG. Transcripts of 3β-HSD, 20β-HSD, and FSH were significantly down-regulated following 28 d exposure to both 16.3 and 86.9 ng/L LNG. Also, CYP19a expression was significantly down-regulated at 86.9 and 2392 ng/L LNG. Subsequently, a second study examined time periods that may be most sensitive (e.g., windows of sensitivity) for FHM larvae exposed to LNG. Larvae were exposed to a single concentration of LNG (i.e. LOECgrowth of 86.2 ng/L as determined in the 28 d ELS study) for different time periods starting with fertilized egg through 28 dph. Growth and mRNA expression of the four differentially expressed transcripts from the first study were measured. Regardless of the duration of exposure, LNG significantly decreased growth in fathead minnow larvae at day 28. For both 20β-HSD and CYP19a, mRNA expression was decreased following exposure to LNG; however, these transcripts returned to baseline levels after removal of LNG. 3β-HSD and FSH showed similar trends after exposure to LNG with 7-14 d and 14-28 d exposures exhibiting a decrease in expression; however, FSH expression returned to baseline once removed for LNG exposure. Based on these data, 3β-HSD was the only transcript to remain down regulated after LNG exposure. Together these data suggest LNG can negatively impact FHM larval survival and growth, with significant alterations in endocrine related responses. However, these changes in endocrine related responses may not directly correlate to the changes in growth demonstrated with LNG exposure to fathead minnows. Therefore, additional research is warranted to ascertain additional mechanisms, either endocrine related or non-endocrine functions, related to changes in growth of larval fathead minnows. digital.library.unt.edu/ark:/67531/metadc283848/
Female Psychopathy Predictors: Cluster B Traits and Alexithymia
Psychopathy has long been lauded as a premier predictor of negative behavioral outcomes because of its demonstrated associations with violence, antisocial conduct, and institutional maladjustment. Traditional conceptualizations of psychopathy highlight the relatively equal importance placed on personality features (i.e., a grandiose, deceitful interpersonal style and deficits in affective experience) and behavioral elements (i.e., an impulsive and irresponsible lifestyle marked by social deviance) of the syndrome. However, little research to date has investigated psychopathy dimensions in female samples, particularly as they relate to maladaptive behaviors beyond forensic settings. The current study comprehensively examined personality (i.e., Axis II Cluster B traits and alexithymia) and behavioral (i.e., suicide-related behavior and aggression) expressions of psychopathy in a sample of female inpatients recruited from trauma and dual-diagnosis units at a psychiatric hospital in Dallas, Texas. Contrary to expectations, the essential components of psychopathy in female psychiatric patients emphasized APD and NPD traits over features of HPD and BPD, which were relatively similar to elements traditionally highlighted in male psychopathy. On this point, two latent dimensions comprehensively addressed female psychopathy in the current sample: impulsive antisociality and narcissistic and histrionic interpersonal style. Interestingly, psychopathy (M r = .01) and Cluster B traits (M r = .05) were virtually unrelated to suicide-related behavior in female patients with trauma and substance use histories, but APD and BPD traits were more discerning for impulsive and premeditated aggression than variants of psychopathy. Aggression's relationship to BPD traits is at least partially mediated by alexithymia. These results are discussed in terms of improving evaluation and intervention efforts aimed at identifying and managing psychopathic females beyond forensic settings. digital.library.unt.edu/ark:/67531/metadc283811/
Factors Related to Teacher Retention: the Lived Experiences of Four Teachers in an Urban, Hard-to-staff High School
Retaining quality teachers is critical to the success of America's schools. How to retain quality teachers, especially in high needs schools, is a question of fervent debate among educational researchers, policy makers, administrators, parents, and students. This study examines the issue of teacher retention from an emic perspective, focused on understanding the perspective of those closest to the retention decision, teachers in hard-to-staff schools. This study examines the lived experiences of four teachers at a hard-to-staff, urban, secondary school as these experiences impact their decisions to remain in teaching and at their current campus. Research methods adopted an existential phenomenological perspective and focused on understanding deeply the perspective of participants and how participants make meaning of their lived experiences as they relate to the retention decision. Three hour-long interviews were conducted with each of the four participants utilizing methodology laid out by Seidman (1991). Data were analyzed using NVIVO 10 to apply a series of coding and recoding procedures to interview transcripts. Conclusions suggest four factors motivated these teachers to teach and remain in their current hard-to-staff, urban, secondary school. These factors include: belief in the power of education, relationships with students, mentoring and professional partnering, and remaining professionally challenged. Findings suggest factors that drive teachers out of teaching and out of hard-to-staff schools include: inconsistent administrative support, low student motivation, and lack of resources. digital.library.unt.edu/ark:/67531/metadc283824/