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 Degree Level: Doctoral
“Sunken Monadnock”: a Composition for Flute, Clarinet, Bassoon, Violin, Violoncello, Electric Guitar, Piano, Percussion, Three Female Vocalists, and Computer
Sunken Monadnock is a scripted combination of three modular musical surfaces. The word “surface” is borrowed from Morton Feldman, who compared the aural surface of music to the canvases of the action painters of the American Abstract Expressionists, and contrasted it with the work’s subject, or organizational structure. Composers’ transition toward a focus on surface through indeterminate compositional techniques, according to Feldman, parallels the development of modernist abstract art. “Sunken Monadnock: Composing with Visual Metaphors” is a companion critical essay that takes the surface/subject metaphor as a starting point for analyzing Sunken Monadnock.Other visual metaphors that inspired Sunken Monadnock, and are discussed in the essay, include Shakir Hassan Al Said’s mystical semiotics, Jasper Johns’s crosshatch prints, and Wassily Kandinsky’s theory of abstraction. The circle and spiral, especially, play influential roles in Sunken Monadnock as reflected by musical applications of repetition, rotation, compression/rarefaction, and endlessness. The void in the circle’s center also comes into play. The nature of the work’s formal counterpoint requires an innovative approach to the score, which consists of five sections, each of which reflects a different approach to the aural surface (i.e., to the traversal of time). The two outer sections are traditionally scored, but the three sections in the middle—labeled “Surfaces” are played simultaneously by three subsets of the ensemble. The piece is approximately 22 minutes long. digital.library.unt.edu/ark:/67531/metadc407859/
A Comparison of Three Teacher Evaluation Methods and the Impact on College Readiness
Much attention in recent years has gone to the evaluation of teacher effectiveness, and some scholars have developed conceptual models to evaluate the effectiveness. The purpose of this study was to compare three teacher evaluation models – the Texas Professional Development Appraisal System (PDAS), the teacher index model (TI), and the value-added model (VAM) – to determine teacher effectiveness using student demographic and longitudinal academic data. Predictive data from students included economic disadvantage status, ethnicity, gender, participation in special education, limited English proficiency, and performance on Texas Assessment of Knowledge and Skills (TAKS). Data serving as dependent variables were scores from Scholastic Aptitude Test (SAT®) verbal/critical reasoning and mathematics. These data came from 1,714 students who were 9.7% Hispanic, 9.2% African American, and 81.2% White. The models were tested for 64 English language arts teachers and 109 mathematics teachers, using student examination scores from the SAT® verbal/critical reasoning and mathematics. The data were aligned for specific faculty members and the students whom they taught during the year of the study. The results of the study indicated that the TI and VAM explained approximately 42% of the variance in college entrance exam scores from the SAT® verbal/critical reasoning and mathematics (R2 = 0.418) across mathematics and English language arts teachers, whereas the TI model explained approximately 40% of the variance in the SAT® scores (R2 = 0.402). The difference, however, in the R-squared values between the VAM and the TI model was not statistically significant (t (169) = 1.84, p > 0.05), suggesting that both models provided similar results. The least effective model used to predict student success on college entrance exams was the PDAS, which is a state-adopted model currently in use in over 1,000 school districts in Texas, The teacher PDAS scores explained approximately 36% of the variance in student success on the SAT® (R2 = 0.359). The study provides school leadership with information about alternative methods of evaluating teacher effectiveness without difficult formulas or high costs associated with hiring statisticians. In addition, results indicate that the models vary significantly in the extent to which they can predict which teachers are most effective in preparing students for college. This study also emphasizes the critical need to provide teacher evaluations that align with student achievement on college entrance exams. digital.library.unt.edu/ark:/67531/metadc407840/
Psychological Diversity Climate and Its Effects: the Role of Organizational Identification
Organizations have begun to focus heavily on diversity. As a result, organizations spend time and resources creating diversity policies and investing extensively in diversity training programs. While an abundance of research exists on demographic diversity, research has just begun to incorporate employees’ perceptions of diversity as an influential factor affecting organizationally relevant employee outcomes. Employees are a crucial reference in understanding whether organizations benefit from engaging in such actions. The purpose of this study is to examine the influence of diversity climate on employees’ organizational identification. Furthermore, I investigate how organizational identification mediates the relationship between diversity climate perceptions and outcomes including turnover intentions, job satisfaction, and organizational citizenship behavior. I refine our understanding by identifying personal characteristics that influence the diversity climate (PDC) – organizational identification (OID) relationship. This research offers several contributions to management literature and scholars as well as practitioners. First this study empirically examines the relationship between PDC and OID. This connection is important as it identifies the psychological mechanism linking PDC to subsequent outcomes as well as showing how positive climate perception can influence an employee’s sense of belonging. The second contribution is the in-depth identification of personal characteristics and their role in this relationship specifically, demographics, values, and attachment to demographic category. Individuals will differ in their beliefs and thus their attachment based on climate perceptions. Finally, this study links diversity climate to organizationally relevant outcomes through organizational identification. digital.library.unt.edu/ark:/67531/metadc407849/
An Examination of Innovations in Alexander Scriabin’s Late Etudes for Piano
Alexander Scriabin (1872-1915) stands as one of the most unconventional twentieth-century Russian composers, particularly with respect to his piano works. The overwhelming majority of Scriabin's compositions—sixty-seven of his seventy-four published works—were written for solo piano. His etudes from 1905 forward are revolutionary, especially compared with his earlier Chopinesque style. Among Scriabin’s twenty-six etudes, his Op.49, No. 1 (1905), Op.56, No. 4 (1908) and the last three etudes of Op.65 (1912) date from his last period of composition. In the Op.49 etude, Scriabin started to abandon traditional tonality. He omitted the key signature altogether in the Op.56 etude. The final three etudes of Op.65 feature constant dissonances on ninths, sevenths and fifths. Alexander Scriabin’s last five etudes represent the culmination of his compositional development and innovations at the piano. Several factors coalesce in these etudes, including unusual harmony, bichords, non-tonal hierarchy, and structural symmetry. Most of these factors derive in some fashion from Scriabin’s increasing reliance upon the so-called “mystic chord” in his late works. This study will illustrate how Scriabin explored new sonorous and aesthetic ideas in his late etudes by means of these innovations. digital.library.unt.edu/ark:/67531/metadc407854/
Titanium Boride Formation and Its Subsequent Influence on Morphology and Crystallography of Alpha Precipitates in Titanium Alloys
Over the last two decades there has been an increased interest in understanding the influence of trace boron additions in Ti alloys. These additions refine the prior β grain size in as-cast Ti alloys along with increasing their modulus and yield strength due to the precipitation of TiB. TiB also acts as a heterogeneous nucleation site for α precipitation and has been shown to influence the α phase morphology. B is completely soluble in liquid Ti but has a negligible solubility in both body centered cubic β and hexagonal close packed α phases of Ti. Thus, during solidification of hypoeutectic B containing alloys, B is rejected from β into the liquid where it reacts with Ti to form pristine single crystal whiskers of TiB. Despite a substantial amount of reported experimental work on the characterization of TiB precipitates, its formation mechanism and influence on α phase precipitation are still not clear. The current work is divided into two parts – (i) understanding the mechanism of TiB formation using first principles based density functional theory (DFT) calculations and (ii) elucidating how TiB influences the α phase morphology and crystallography in titanium alloys using electron microscopy techniques. TiB exhibits anisotropic growth morphology with [010] direction as its predominant growth direction and displays a hexagonal cross section with (100), (101), and (10) as the bounding planes. A high density of stacking faults has been experimentally observed on the (100) plane. The present study, by using DFT based nudged elastic band (NEB) calculations, elucidates for the first time that the diffusion of B through TiB is via an interstitial-assisted mechanism as opposed to vacancy-assisted mechanism hypothesized in literature. This one dimensional interstitial-assisted diffusion results in the anisotropic growth of TiB. In addition, the energetics of TiB- α interfaces was calculated to understand the hexagonal cross-section of TiB. The intimate mixing of B27 and Bf structures and their co-existence with stacking faults has been explained by calculating the interfacial energy of B27/Bf interfaces along with stacking fault formation energy. The boride precipitates have also been shown to modify the morphology of α phase from lath like to more equiaxed like. However, the influence of TiB on the crystallography of α precipitation has not been explored in great detail. The present study will clearly demonstrate, for the first time, the influence of various alloying elements present in the titanium alloy, on the resulting effect of B addition on α morphology and its crystallography in Ti alloys. Thus, the influence of B addition on α precipitation in two classes of commercial Ti alloys, i.e. β alloys and α + β alloys have been explored. It has been found that TiB nucleated α can either become equiaxed by a loss of Burgers orientation relationship (OR) with β or can retain the lath morphology in case of alloys containing a combination of Ti, Al and Mo. digital.library.unt.edu/ark:/67531/metadc407855/
Ye Si Ye Jong: a Martial Arts Approach to Business Ethics
The purpose of this dissertation is to offer a new approach to business ethics grounded in the martial arts. This dissertation argues that traditional rules and regulations approaches to business ethics, though important, are inadequate. Such “top down” approaches must be complimented with corporate reform that comes “from the inside out.” The dissertation consults the martial arts to develop a core, multifaceted virtue – Ye Si Ye Jong – that ought to form the foundation for creating a corporate culture (or an ethos for business) that embraces a new approach to decision-making at every level of the organization – from the boards of directors, to individual employees. This dissertation frames the problem as a matter of corporate culture or ethos. This framing is a distinctive approach to corporate or business ethics in two respects: its emphasis on virtue and its integration of core concepts from the martial arts. This dissertation utilizes an uncommon example of business decision-making as its source for a case-study – a prominent university. While many may not think of colleges or universities as exemplars of common business activities, they do, in fact, provide a source of many ethical business dilemmas, both common and unique. Universities have boards of directors, consumers (students and others), and regularly evaluate many financial and cost accounting situations that are not unusual to most businesses. The Jerry Sandusky case at Penn State University provides an opportunity that is ripe for consideration of various business ethics decision-making and, as such, is analyzed later in this paper. digital.library.unt.edu/ark:/67531/metadc407848/
Performer’s Guide to the Execution and Application of Karen Tuttle’s Coordination, As Applied to Ernest Bloch’s Suite Hébraïque
Legendary violist and pedagogue Karen Tuttle developed a new approach to playing the viola known as Coordination. Coordination consists of a deep emotional connection to music, as well as highly specific motions of the body. This document details the execution of the physical motions of Coordination, through written descriptions and multimedia examples. A detailed discussion of the application of the motions is presented, using notated examples from Ernest Bloch’s Suite Hébraïque. digital.library.unt.edu/ark:/67531/metadc407842/
The Academic and Athletic Experiences of African-american Males in a Division I (Fbs) Football Program
This study investigated the academic and athletic experiences of African-American males in a Division I football bowl subdivision football program. Critical race theory, identity development model, and social learning model were the theoretical frameworks used as the critical lenses in a qualitative design to examine the participants. The participants’ responses were analyzed and interpreted using thematic analysis. A qualitative research design, which included individual interviews with 10 second year African-American male football players, was used to address this research problem. The goal was to bring together both the psychological and sociological perspectives and to challenge participants to candidly describe their academic and athletic experiences and attitudes toward obtaining an undergraduate degree. Four themes were determined in the data analysis: differential treatment and determining oneself, time management, relationships, and career aspirations. In relation to the theoretical frameworks, the development of self-confidence and knowledge of balancing their academic and athletic schedules was critical for all participants. The sense of feeling different and challenged because of the differences in culture and experience was evident. From this study, university and collegiate athletics administrators may better understand the backgrounds, challenges, and learning needs of this population. As a result, higher education personnel may improve the services they provide these young men in hopes of educating and developing whole persons—physically, emotionally, intellectually, socially, and spiritually—to become well-rounded and functional in contemporary society. digital.library.unt.edu/ark:/67531/metadc407844/
Shakespeare and Modeling Political Subjectivity
This dissertation examines the role of aesthetic activity in the pursuit of political agency in readings of several of Shakespeare’s plays, including Hamlet (1600), A Midsummer Night’s Dream (1595), The Tempest (1610), the history plays of the second tetralogy (1595-9), Julius Caesar (1599), and Coriolanus (1605). I demonstrate how Shakespeare models political subjectivity—the capacity for individuals to participate meaningfully in the political realm—as necessitating active aesthetic agency. This aesthetic agency entails the fashioning of artistically conceived public personae that potential political subjects enact in the public sphere and the critical engagement of the aesthetic and political discourses of the subjects’ culture in a self-reflective and appropriative manner. Furthermore, these subjects should be wary auditors of the texts and personae they encounter within the public sphere in order to avoid internalizing constraining ideologies that reify their identities into forms less conducive to the pursuit of liberty and social mobility. Early modern audiences could discover several models for doing so in Shakespeare’s works. For example, Hamlet posits a model of Machiavellian theatricality that masks the Prince's interiority as he resists the biopolitical force and disciplinary discourses of Claudius's Denmark. Julius Caesar and Coriolanus advance a model of citizenship through the plays’ nameless plebeians in which rhetoric offers the means to participate in Rome’s political culture, and Shakespeare’s England for audiences, while authorities manipulate citizen opinion by molding the popularity of public figures. Public, artistic ability affords potential political subjects ways of not only framing their participation in their culture but also ways of conceiving of their identities and relationships to society that may defy normative notions of membership in the community. digital.library.unt.edu/ark:/67531/metadc407853/
The Effect of It Process Support, Process Visualization and Process Characteristics on Process Outcomes
Business process re-engineering (part of the Business Process Management domain) is among the top three concerns of Information Technology (IT) leaders and is deemed to be one of many important IT leveraging opportunities. Two major challenges have been identified in relation to BPM and the use of IT. The first challenge is related to involving business process participants in process improvement initiatives using BPM systems. BPM technologies are considered to be primarily targeted for developers and not BPM users, and the need to engage process participants into process improvement initiatives is not addressed, contributing to the business-IT gap. The second challenge is related to potential de-skilling of knowledge workers when knowledge-intensive processes are automated and process knowledge resides in IT, rather than human process participants. The two identified challenges are not separate issues. Process participants need to be knowledgeable about the process in order to actively contribute to BPM initiatives, and the loss of process knowledge as a result of passive use of automated systems may further threaten their participation in process improvement. In response to the call for more research on the individual impacts of business process initiatives, the purpose of this dissertation study is to understand the relationship between IT configurations (particularly process support and process visualization), process characteristics and individual level process outcomes, such as task performance and process knowledge. In the development of the research model we rely on organizational knowledge creation literature and scaffolding in Vygotsky’s Zone of Proximal Development, business process modeling and workflow automation research, as well as research on the influence of IT on individual performance. The theoretical model is tested empirically in experimental settings using a series of two studies. In both studies participants were asked to complete tasks as part of a business process using different versions of a mock-up information system. Together, the studies evaluate the effect of IT process support, process visualization and process complexity on process participant performance and process knowledge. The results of the studies show the significant influence of IT process support on individual process outcomes. The studies indicate that task performance does increase but at the cost of users’ process knowledge. Process visualization however is shown to enhance user’s process knowledge in the event of no formal process training while having no negative impact on task performance. The key contribution of this research is that it suggests a practical way to counteract potential negative effects of IT process automation by converting the use of the information system into a learning experience, where the IT itself acts as a scaffold for the acquisition of process knowledge. The results have practical implications for the design of workflow automation systems, as well as for process training. digital.library.unt.edu/ark:/67531/metadc407777/
Evaluating the Cultural Plan of Austin, Texas
This is a concurrent, mixed methods study of the impacts of Austin, Texas’s cultural plan, CreateAustin. In the study, trend analysis and a t-test were used to examine variables before and after the cultural plan was in place. At the same time, interviews with cultural planners were used to uncover other effects. My research addresses a gap in the literature between understanding the desired and actual outcomes of a cultural plan. Cultural plans are being developed by many communities in an effort to attract creative workers but they are rarely evaluated. Evaluation using a mixed methods approach is necessary to capture all the outcomes of a cultural plan, rather than the limited scope of impacts that are captured by qualitative or quantitative analyses alone. My analysis of the quantitative variables showed some significant differences between when the plan was in place and the years prior to its creation. Interviews with key stakeholders revealed the formation of new networks as a powerful outcome of the planning process. The results allowed me to gauge the overall impact of CreateAustin and make some observations about the cultural planning process in general, as well as uncover new directions for future research. digital.library.unt.edu/ark:/67531/metadc407737/
Web Information Behaviors of Users Interacting with a Metadata Navigator
The web information behaviors of users as they interacted with a metadata navigator, the Personal Information (PI) Agent, and reflected upon their interaction experiences were studied. The process included studying the complete iterative (repeated) cycle of information needs, information seeking, and information use of users interacting with an internet-based prototype metadata PI Agent tool. Detlor’s theory of web information behaviors of organizational users was utilized as a theoretical foundation for studying human-information interactions via the PI Agent tool. The qualitative research design allowed for the use of triangulation within the context of a one-group pretest-posttest design. Triangulation occurred in three phases: (a) observe, (b) collect, and (c) reflect. Observations were made as participants solved three problem situations. Participants’ computer log and print screen data were collected, and follow-up interviews were conducted once all posttest sessions ended to enable users to reflect on their experiences. The three triangulation phases ensured saturation of data and greater depth regarding the participants’ information behaviors. Content analysis occurred via exploratory pattern analysis using the posttest Problem Steps Recorder (PSR) log data and on the six interviewees’ follow-up interview data. Users engaged in iterative cycles of information needs, information seeking, and information use to resolve the presented problem situations. The participants utilized the PI Agent tool iteratively to eliminate their knowledge gaps regarding the presented problem situations. This study was the first to use PSR log data for capturing evidence of the iterative search process as defined by Detlor. The implications for best practices were inspired by participant feedback, and recommendations for further study are made. digital.library.unt.edu/ark:/67531/metadc407784/
Social Innovation in Venture Capital Firms: Strategy, Structure, and Performance
Social innovations are solutions related to humanistic needs and the betterment of mankind with the intent of creating social value and eventual societal level changes. Social innovation therefore broadens traditional views of innovation to include processes of societal transformations and human behaviors. These social innovations are becoming more commonplace across all sectors, including capital markets. Private equity and venture capital firms in the capital markets sector engage in social innovation by investing capital with the goal of delivering both economic and social value. Despite the critical importance of venture capital (VC) in the success of social innovations through socially responsible investing, there is a paucity of research in understanding the factors that affect the performance of these social VC firms. This research gap is addressed by asking the following primary research question: What is the role of strategic and structural factors in the performance of socially innovative venture capital firms? The firm level research is theoretically based on the well-established design school. This framework highlights the overarching importance of strategy and structure in the accomplishment of firm goals. In the context of the venture capital industry, it was hypothesized that certain unique strategic and structural factors (i.e., stage of investment, age, size, and network relationships) would influence the performance of socially innovative VC firms. A moderated mediation model was proposed to examine these factors and their influence on performance variation. The sample of socially innovative VC firms was generated from the ThomsonOne Private Equity Database. The research design and methodology followed a systematic and objective process. This included identification of the sample of 381 VC firms, collection of mission statements for each VC firm, development of key word list pertaining to social innovation for content analysis and the collection of archival data on each VC firm. Content analysis was then used to identify the degree to which the firm’s strategic orientation (mission statement) was related to social innovation. Finally, both traditional and more cutting edge statistical analyses (Preacher & Hayes, 2008) were used to evaluate the moderated mediation model. The results of this study provide several key take-a-ways for both researchers and practitioners focusing on social venture capital. Firstly, results indicated that firms adopt distinct foci of social investing that directs their strategic orientation. These various foci have vastly differing effects on the firm’s overall performance, the strategic decisions they make, and the architecture of their structural design. It is therefore necessary to treat each focus area separately given differences in strategies, industry and investment focus, and market orientations. Secondly, including socially related language in the firm’s mission statement does not guarantee that a VC firm will actually implement a social orientation or seek to create the social value inherent in social innovation. Thirdly, certain investment strategies appear to be more advantageous depending of the size of the firm and the socialness of the firm’s orientation. Lastly, results supported that the adoption of a social orientation did not negatively influence firm performance. Overall, results suggest that pursuing a social orientation is viable and effective in delivering blended value strategies for VC firms engaging in social innovation. These findings offers socially oriented venture capital firms insights into strategic and structural aspects that are important to their success in achieving positive exists of their portfolio companies, thus increasing both financial and social value. digital.library.unt.edu/ark:/67531/metadc407767/
Assessing Local Governments’ Debt Financing Strategies
This dissertation assesses the importance of a specific debt instrument, the Certifi- cate of Obligation in the state of Texas. It conceptualizes the Certificate of Obligation as a type of contractual debt that enables local governments to finance their capital projects. This dissertation is guided by three research questions: (1) What are the various types of debt instruments employed by local governments and what are their relative advantages? (2) How prevalent is the use of a specific debt instrument such as Certificates of Obligation? And why would some local governments prefer to issue them while others do not? (3) To what extent does the local institutional environment, e.g., the executive authority of city managers in the council-manager form of government, affect debt financing behaviors of local governments? To examine the first research question, we created a typology to represent four ideal types of borrowing methods: (1) Contractual Debt, (2) Voter Approval/Special Tax Debt, (3) Guaranteed, and (4) Non-Guaranteed Debts. The typology examines whether or not the state mandates the referendum requirement for the use of each of these debt instruments, and at the same time determines whether each debt instrument is secured by multiple or single revenue sources. Using data we collected among municipal governments in Texas, we conducted two empirical analyses. The first analysis tests the hypothesis that Certificates of Obligation have higher borrowing costs compared to GO bonds, since a GO bond is often issued under the pledge of the bond issuers’ full-faith credit and taxing authority. We employed a two-stage least square analysis to test the general proposition in the state of Texas. Based on 741 Certificates of Obligation and GO bonds issued between 2008 and 2011, our analyses show that Certificates of Obligation are likely to incur True Interest Costs (TIC) similar to those of GO bonds. The second analysis explores factors explaining the use of Certificates of Obligation in 225 Texas charter cities. Based on Heckman’s two-stage, we found that a local government’s decision to issue Certificates of Obligation to be partly explained by the characteristics of local population, i.e., median household income, population growth, and the percentage of senior citizens living in the jurisdiction. In the case of GO bonds, we found that population size, property tax rate, debt burden, and the percentage of population with at least a college education, to be an important determinant of GO bonds. The volume of GO issuance by local governments was also related to the level of regional competition, i.e., government density. Additionally, we found that local political institutions matter and that they affect debt financing behaviors of local governments. digital.library.unt.edu/ark:/67531/metadc407780/
Churches, Social Service Access and Korean-american Elders: an Exploratory Study
This study examined how Korean co-ethnic churches serve as connections between Korean seniors and the agencies that offer social and health care services. The study developed from a pilot outreach program funded by the North Central Texas Council of Governments’ Area Agency on Aging (NCTAAA) to inform Korean seniors about Medicare-related programs between February and May of 2011. The results of the pilot program suggested that the Korean-American church can be an effective place for program outreach. The dissertation project, working in partnership with the NCTAAA and 2-1-1 services, further explored the use of Korean churches as a vehicle to connect Korean seniors to Extra Help (EH) and Medicare Saving Programs (MSP) and 2-1-1 services, a toll-free number for information about non-emergency health and social services. Fifty-three pastors were contacted to participate in a telephone survey and a face-to-face, in-depth semi-structured interview. Thirty telephone surveys and 11 face-to-face interviews were conducted. Five of the 30 pastors agreed to host program outreach presentations for the EH, MSP, and 2-1-1 services in their churches. Host churches tended to be more likely highly structured, regularly scheduled programs (e.g., Senior College) for seniors already in place. A total of 405 Korean seniors participated in the program outreach sessions. Five seniors received the EH application information, and 17 MSP application forms were distributed. Additionally, 28 seniors were assisted by phone, not only with the targeted programs, but also with other benefits information. Together, these outcomes indicate that the co-ethnic church can be a vehicle to connect Korean seniors to services offered by outside agencies. digital.library.unt.edu/ark:/67531/metadc407746/
Integrated Computational and Experimental Approach to Control Physical Texture During Laser Machining of Structural Ceramics
The high energy lasers are emerging as an innovative material processing tool to effectively fabricate complex shapes on the hard and brittle structural ceramics, which previously had been near impossible to be machined effectively using various conventional machining techniques. In addition, the in-situ measurement of the thermo-physical properties in the severe laser machining conditions (high temperature, short time duration, and small interaction volume) is an extremely difficult task. As a consequence, it is extremely challenging to investigate the evolution of surface topography through experimental analyses. To address this issue, an integrated experimental and computational (multistep and multiphysics based finite-element modeling) approach was employed to understand the influence of laser processing parameters to effectively control the various thermo-physical effects (recoil pressure, Marangoni convection, and surface tension) during transient physical processes (melting, vaporization) for controlled surface topography (surface finish). The results indicated that the material lost due to evaporation causes an increase in crater depth of machined cavity, whereas liquid expulsion created by the recoil pressure increases the material pileup height around the lip of machined cavity, the major attributes of surface topography (roughness). Also, it was found that the surface roughness increased with increase in laser energy density and pulse rate (from 10 to 50Hz), and with the decrease in distance between two pulses (from 0.6 to 0.1mm) or the increase in lateral and transverse overlap (0, 17, 33, 50, 67, and 83%). The results of the computational model are also validated by experimental observations with reasonably close agreement. digital.library.unt.edu/ark:/67531/metadc407758/
An Examination of Mathematics Teachers’ Use of Student Data in Relationship to Student Academic Performance
Among educational researchers, important questions are being asked about how to improve mathematics instruction for elementary students. This study, conducted in a north Texas public school with 294 third- through fifth-grade students, ten teachers and three coaches, examined the relationship between students’ achievement in mathematics and the mathematics teaching and coaching instruction they received. Student achievement was measured by the Computer Adaptive Instrument (CAT), which is administered three times a year in the district and is the main criterion for students’ performance/movement in the district’s response to intervention program for mathematics. The response to intervention model employs student data to guide instruction and learning in the classroom and in supplemental sessions. The theoretical framework of the concerns based adoption model (CBAM) was the basis to investigate the concerns that mathematics teachers and coaches had in using the CAT student data to inform their instruction. The CAT data, based on item response theory, was the innovation. Unique in this study was the paralleling of teachers’ and coaches’ concerns and profiles for their use of the data with student scores using an empirical approach. Data were collected at three intervals through the Stages of Concerns Questionnaire, the Levels of Use interviews, and the Innovation Configuration Components Matrix from teachers and at three intervals student CAT-scaled scores. Multiple regression analyses with the concerns and CAT scores and levels of use and CAT scores were conducted to determine if relationships existed between the variables. The findings indicated that, overall, the teachers and coaches who scored high in personal concerns at the three data points remained at low levels of use or non-use of CAT data in their instruction. Only two teachers indicated movement from high intense personal concerns to high concerns regarding the impact on students. This correlated with their increased use of CAT at the three-collection points. The regression analyses indicated no correlations between the teachers’ and coaches’ concerns and the CAT and no correlations between their levels of data use and the CAT. At the exit interviews, patterns suggested that the presence of a change facilitator might have made a difference in their understanding and use of the CAT data ultimately impacting student achievement. This study sets a new precedent in the use of CBAM data and offers insights into the necessity of providing support and training in a change process. digital.library.unt.edu/ark:/67531/metadc407744/
Boosting for Learning From Imbalanced, Multiclass Data Sets
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In many real-world applications, it is common to have uneven number of examples among multiple classes. The data imbalance, however, usually complicates the learning process, especially for the minority classes, and results in deteriorated performance. Boosting methods were proposed to handle the imbalance problem. These methods need elongated training time and require diversity among the classifiers of the ensemble to achieve improved performance. Additionally, extending the boosting method to handle multi-class data sets is not straightforward. Examples of applications that suffer from imbalanced multi-class data can be found in face recognition, where tens of classes exist, and in capsule endoscopy, which suffers massive imbalance between the classes. This dissertation introduces RegBoost, a new boosting framework to address the imbalanced, multi-class problems. This method applies a weighted stratified sampling technique and incorporates a regularization term that accommodates multi-class data sets and automatically determines the error bound of each base classifier. The regularization parameter penalizes the classifier when it misclassifies instances that were correctly classified in the previous iteration. The parameter additionally reduces the bias towards majority classes. Experiments are conducted using 12 diverse data sets with moderate to high imbalance ratios. The results demonstrate superior performance of the proposed method compared to several state-of-the-art algorithms for imbalanced, multi-class classification problems. More importantly, the sensitivity improvement of the minority classes using RegBoost is accompanied with the improvement of the overall accuracy for all classes. With unpredictability regularization, a diverse group of classifiers are created and the maximum accuracy improvement reaches above 24%. Using stratified undersampling, RegBoost exhibits the best efficiency. The reduction in computational cost is significant reaching above 50%. As the volume of training data increase, the gain of efficiency with the proposed method becomes more significant. digital.library.unt.edu/ark:/67531/metadc407775/
Relationships of Benthic Macroinvertebrate Community Structure with Land-use, Habitat, In-stream Water Chemistry, Depositional Sediment Biofilm Fatty Acids, and Surfactants in the Effluent Dominated Texas Trinity River
The Trinity River is an urbanized, effluent-dominated river, and is heavily relied upon for drinking water. The benthic macroinvertebrate community has been monitored for over 20 years, with the focus of this dissertation on three studies (1987-88, 2005, and 2011). Water quality improvement following dechlorination resulted in increased benthic metrics. Overall habitat quality, in-stream cover, surface water total organic carbon, sediment total organic carbon, near-field urban land-use, near-field forested land-use, surface water surfactant toxic units, and depositional sediment biofilm fatty acids all have statistically significant relationships with benthic macroinvertebrate metrics. These relationships are better defined with increased taxonomic resolution at the genus/species level for all benthic taxa, including Chironomidae and Oligochaeta. It is recommend that benthic identifications for state and city water quality assessments be done at the genus/species level. A novel method for quantifying depositional sediment biofilm fatty acids has been produced and tested in this dissertation. Benthic metrics are directly related to fatty acid profiles, with several essential fatty acids found only at upstream sites. digital.library.unt.edu/ark:/67531/metadc407738/
Adolescent Behavior Problems and Interparental Conflict: the Moderating Role of Parent-child Attachment
The current study examined the role that parent-child attachment plays in the relationship between marital conflict and the development of behavior problems in adolescents. To evaluate the hypothesis that attachment moderates this relationship, 57 families were recruited via e-mail invitation sent to families that participated in local church youth groups, school organizations, and a treatment program designed for adolescents with behavior problems. One custodial parent and his/her adolescent child completed an online or paper version of a survey consisting of the Achenbach’s Behavior Checklists, the Inventory of Parent and Peer Attachment, and the Children’s Perception of Interparental Conflict Scale. Hypotheses were evaluated using Baron and Kenny’s (1986) procedures to test moderating effects with multiple regression analyses. Mother attachment demonstrated a significant moderation effect between the intensity of interparental conflict and the parent’s report of externalizing behavior problems. Specifically, at low conflict intensity levels, relative to low attachment security, high attachment security was associated with fewer externalizing behavior problems, whereas at high intensities of interparental conflict high attachment security was associated with more externalizing behavior problems. digital.library.unt.edu/ark:/67531/metadc407793/
Examining High School Coaches’ Likelihood to Refer To, Interest in Working With, and Plans to Hire a Sport Psychologist
The primary goal of the current study was to extend previous research suggesting that coaches are the primary gatekeepers who may be a barrier to working with athletes by examining high school coaches likelihood to refer to, interest in, and intention to hire a sport psychologist. Specifically, the current study examined relationships between high school coaches’ sex, age, and type of sport coached (i.e., contact vs. non-contact) and their likelihood to refer athletes to a sport psychologist for a variety of presenting issues (i.e., poor attentional focus, poor leadership, family issues, etc.). It also examined relationships between coaches’ sex, age, and type of sport coached (i.e., contact vs. non-contact) and their interest in working with a sport psychologist. Finally, the study examined reasons why coaches did not plan to hire a sport psychologist. An examination of the possible reasons that high school coaches do not plan to hire a sport psychologist served an exploratory purpose. Participants included 450 coaches who coached high school sports in the United States. Results indicated that female coaches and non-contact sport coaches were more likely to refer athletes to a sport psychologist for a variety of referral issues than male coaches and coaches of contact sports. Similarly, significantly more female coaches and non-contact sport coaches showed interest in working with a sport psychologist than male coaches and coaches of contact sports. Coaches who did not plan to hire a sport psychologist reported that cost, lack authority to hire, and lack of availability as primary reasons. Implications of the findings, limitations, and future directions are discussed. digital.library.unt.edu/ark:/67531/metadc407762/
Funds of Knowledge in a Hispanic Household: a Case Study of Family Experiences, Values, and Connections to Education
Traditionally, the field of education has often adopted a negative perspective in their views of minority families’ contributions to the educational progress of their children. However, research embodying the theoretical framework of ‘funds of knowledge’ attempts to counter that model through its assertion that all families possess extensive bodies of knowledge that have developed through social, historical, and cultural contexts. Teachers carry out studies of familial funds of knowledge in order to understand how family experiences shape the knowledge that a child brings to the classroom. There is then, the potential to use that body of knowledge to create meaningful learning experiences that connect prior understanding and experiences to classroom practice. This research served as a case study of the funds of knowledge existing in the home of a Hispanic family and the connections that existed between that knowledge and literacy. The results indicated that the family possessed extensive funds of knowledge that developed through their historical, cultural, and social experiences. They often used family networks, as well as formal and informal literacy experiences to share this knowledge with their children. A key component of the literacy value system that they communicated resulted from a desire to maintain aspects of their culture and heritage through maintaining and improving their children’s reading and linguistic abilities in Spanish. Furthermore, along with their emphasis on Spanish literacy, they held aspirations for their children related to familial and educational values that often stemmed from their expressed desire for their children to lead lives with greater opportunities and positive examples than they had experienced. digital.library.unt.edu/ark:/67531/metadc407772/
Population Dynamics of Zebra Mussels (Dreissena Polymorpha) in a North Texas Reservoir: Implications for Invasions in the Southern United States
This dissertation has two main objectives: first, quantify the effects of environmental conditions on spatio-temporal spawning and larval dynamics of zebra mussels (Dreissena polymorpha [Pallas 1771]) in Lake Texoma, and second, quantify the effects of environmental conditions on survival, growth, and reproduction of young of the year (YOY) juvenile zebra mussels. These biological responses directly influence population establishment success and invasive spread dynamics. Reproductive output of the zebra mussel population in Lake Texoma was significantly related to water temperature and lake elevation. Annual maximum larval (veliger) density decreased significantly indicating a population crash, which was likely caused by thermal stress and variability of lake elevation. In 2011, temperatures peaked at 34.3°C and lake elevation decreased to the lowest level recorded during the previous 18 years, which desiccated a substantial number of settled mussels in littoral zones. Estimated mean date of first spawn in Lake Texoma was observed approximately 1.5 months earlier than in Lake Erie, and peak veliger densities were observed two months earlier. Veligers were observed in the deepest oxygenated water after lake stratification. During a 69-day in situ experiment during summer in Lake Texoma, age-specific mortality of zebra mussels was generally high until temperatures decreased to approximately 28°C, which was observed after lake turnover in late summer. No study organism died after temperatures decreased to less than 26°C, which indicates individuals that survive high summer temperatures are likely to persist into autumn/winter. Shell length growth and soft tissue growth rates were related to temperature and chlorophyll-a concentration, respectively. Growth rates of study organisms were among the highest ever reported for D. polymorpha. Water temperature and body size influenced reproduction of YOY zebra mussels in Lake Texoma. Fecundity of females were positively related to temperature; however, sperm production was negatively related to temperature, which indicates males could be more sensitive to physiologically-stressful conditions than females and could perform better in cooler waters. YOY mussels spawned up to approximately 40,000 eggs and 3.47E+08 sperm after a single-summer growing season. Reproductive effort and reproductive mass were independent of sex. YOY individuals from each study site (n = 5) were able to spawn viable gametes capable of sperm binding and egg cleavage, which provides the first evidence that YOY zebra mussels can successfully reproduce. Individual mortality of zebra mussels will likely be high in warm waters and intermittent, extreme droughts, which are observed more frequently at lower latitudes, can significantly reduce population sizes. However, rapid growth and single-season maturation can decrease generation times and could facilitate establishment and spread of zebra mussels in warm-water environments in the southern United States. digital.library.unt.edu/ark:/67531/metadc407755/
American Indian Worldviews, Risk Perceptions and Disaster Planning: an Exploratory Study
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It is commonly assumed that when confronted with an imminent hazard that people will react rationally, and prepare for, or at least attempt to avoid, danger from pending disasters. However, this conventional wisdom is not as evident as it appears. People prepare for, react to, or take social action to avoid hazards when they perceive the risk of danger to be threatening enough to warrant action, providing one has the will, insight and resources to do so. However, not all people perceive risks similarly. Risk is perceived differently by different people which affects risk perception and responses to hazards. This dissertation explores the relationships between American Indian worldviews, risk perceptions and disaster planning. To carry out this research 28 American Indians were interviewed. The sample consists of 14 American Indians residing in a rural are on the northern plains and 14 urban American Indians. The results only partially support that worldview is linked to risk perception and subsequent disaster planning. Other factors found to relate to risk perception and disaster planning for this non-representative sample of American Indians include various forms of social vulnerability. digital.library.unt.edu/ark:/67531/metadc407742/
Analyzing Delinquency Among Kurdish Adolescents: a Test of Hirschi’s Social Bonding Theory
This study examines the mediating effect of social bonding on delinquent behavior among Kurdish teens. Major influences to the study of self concept and delinquency based on Hirschi’s social bonding theory are reviewed. The data was collected from a sample of 100 Kurdish teens attending a Gülen affiliated school (Private Çaglayan Murat Anatolian Science High School in Şanlıurfa, Turkey) and 100 Kurdish teens attending a public (non- Gülen) school (The Public High School in Diyarbakır, Turkey). There are two dependent variables for this research project: Involvement in major delinquency and involvement in minor delinquency. The components of social bonding attachment, involvement, commitment, and belief were used as independent variables. Participants’ age ranged between 16 to 18 years. I hypothesize that the relation between the social bonding elements and delinquency should be stronger in the case of Kurdish adolescents who are more attached to conventional Turkish society. Results from binary logistic regression analyses indicate that in the absence of bonding, Kurdish teenagers tend to engage in major and minor delinquent activities. For further exploration and results, the Gülen Movement was examined as an independent variable. Findings suggest a strong relationship between the Gülen Movement and Kurdish adolescents’ probability of involvement in either major or minor delinquent activities. Finally, several directions for future research on Hirschi’s social bonding theory are recommended and some implications are drawn for deterring Kurdish adolescents from becoming involved in delinquent actions. digital.library.unt.edu/ark:/67531/metadc407795/
From Aspiration to Attainment: African American Community College Transfer Student Experiences Through Baccalaureate Degree Attainment
The purpose of this dissertation was to explore African American community college transfer student experiences through baccalaureate degree completion. The current study used qualitative methods to examine the experiences and perceptions of eighteen African American community college transfer students who recently graduated or were within 30 credit hours of graduating from a four-year university in Texas. Ten female and eight male students, ranging in age from 21 to 56 years old, with an average age of 28, composed the sample. Data were collected through semi-structured interviews which were transcribed and analyzed based on an integrated conceptual model of Padilla’s (1999) Model of Minority Student Success and Yosso’s (2005) Community Cultural Wealth Model. Findings suggest that African American community college transfer student experiences are very similar to transfer student experiences revealed in current literature. However, findings indicate students perceive their experiences differ from student of other races/ethnicities when dealing with negative stereotypes, lack of role models, and racial bias. Findings also suggest African American community college transfer student persist by employing transfer student capital, familial, aspirational, and resistant capital to learn how the traverse transfer, transition, and persistence through baccalaureate degree attainment. digital.library.unt.edu/ark:/67531/metadc407745/
Molecular and Functional Characterization of Medicago Truncatula Npf17 Gene
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Legumes are unique among plants for their ability to fix atmospheric nitrogen with the help of soil bacteria rhizobia. Medicago truncatula is used as a model legume to study different aspects of symbiotic nitrogen fixation. M. truncatula, in association with its symbiotic partner Sinorhizobium meliloti, fix atmospheric nitrogen into ammonia, which the plant uses for amino acid biosynthesis and the bacteria get reduced photosynthate in return. M. truncatula NPF1.7 previously called MtNIP/LATD is required for symbiotic nitrogen fixing root nodule development and for normal root architecture. Mutations in MtNPF1.7 have defects in these processes. MtNPF1.7 encodes a member of the NPF family of transporters. Experimental results showing that MtNPF1.7 functioning as a high-affinity nitrate transporter are its expression restoring chlorate susceptibility to the Arabidopsis chl1-5 mutant and high nitrate transport in Xenopus laevis oocyte system. However, the weakest Mtnip-3 mutant allele also displays high-affinity nitrate transport in X. laevis oocytes and chlorate susceptibility to the Atchl1-5 mutant, suggesting that MtNPF1.7 might have another biochemical function. Experimental evidence shows that MtNPF1.7 also functions in hormone signaling. Constitutive expression of MtNPF1.7 in several species including M. truncatula results in plants with a robust growth phenotype. Using a synthetic auxin reporter, the presence of higher auxin in both the Mtnip-1 mutant and in M. truncatula plants constitutively expressing MtNPF1.7 was observed. Previous experiments showed MtNPF1.7 expression is hormone regulated and the MtNPF1.7 promoter is active in root and nodule meristems and in the vasculature. Two potential binding sites for an auxin response factors (ARFs) were found in the MtNPF1.7 promoter. Chromatin immunoprecipitation-qRT-PCR confirmed MtARF1 binding these sites. Mutating the MtARF1 binding sites increases MtNPF1.7 expression, suggesting a mechanism for auxin repression of MtNPF1.7. Consistent with these results, constitutive expression of an ARF in wild-type plants partially phenocopies Mtnip-1 mutants’ phenotypes. digital.library.unt.edu/ark:/67531/metadc407747/
The Use of a Stimulus Control Transfer Procedure to Teach Spontaneous Manding to Children with Autism
Current research indicates that the inability to spontaneously communicate needs or wants may result in the acquisition of unconventional forms of requesting such as aggression and tantrums. This in turn limits the amount of access that students with autism have to neurotypical peers and social environments. The purpose of this study was to investigate the effect of using a stimulus control transfer procedure on the acquisition of spontaneous mands. Four school-aged children with autism, two boys and two girls, participated in the study. A multiple baseline design across participants was utilized to demonstrate a functional relation between the stimulus control transfer procedures and the rate of spontaneous mands. Measurement variables included the frequency of spontaneous versus multiply-controlled mands during discrete trial training on a variety of verbal operants. Effectiveness of the intervention was analyzed through visual analysis and the magnitude of effect was assessed through effect size. Visual analysis indicated that three of the four participants learned to spontaneously mand for items out of view and demonstrated generalization across targets, staff and environments. The effect size for three participants were large (d = 1.94; d = 2.2; and d = 1.4), whereas the outcome of intervention for one participant (d = 0.98) indicated moderate effect. The overall (d = 1.15) outcome demonstrated a large effect of the intervention on the rate of mands. Based on the results of this study, it is recommended that early and intensive behavior intervention programs for children with autism incorporate this type of procedure for socially significant outcomes. digital.library.unt.edu/ark:/67531/metadc407751/
The Effect of Stock Splits on Small, Medium, and Large-sized Firms Before and After Decimalization
This study examines the impact of reducing tick size and, in particular decimalization on stock splits. Based on previous studies, this study examines hypotheses in the following three areas: first, market reaction around stock split announcement and ex-dates, second, the effect of tick size on liquidity after stock split ex-dates, and third, the effect of tick size on return volatility after stock split ex-dates. The impact of tick size on market reaction around split announcement and ex-dates is measured by abnormal returns and buy and hold abnormal returns (BHARs). Also, this study investigates the long term impact of decimalization on market reaction for small, medium, and large firms for the three different tick size periods. The effect of tick size on liquidity after stock split ex-dates is measured by turnover, relative bid ask spread, and market maker count. The effect of tick size on return volatility around stock split announcement and ex-dates is measured by return standard deviation. Also, this study investigates the long term impact of decimalization on volatility after split ex-dates for small, medium, and large firms for three different tick size periods. digital.library.unt.edu/ark:/67531/metadc407794/
The Extent of Autism Knowledge of Novice Alternatively Certified Special Education Teachers in Texas
An increase in the prevalence rate of autism is not necessarily matched by a concurrent increase in the rate of highly qualified special education teachers. The low ratio of highly qualified teachers to the number of students with autism has resulted in chronic teacher shortages in this area. Alternative certification is used as a mechanism to alleviate the demand for highly qualified teachers in special education. However, alternative certification routes have often left novice teachers underprepared for teaching students with autism, more specifically in the implementation of evidence-based practices necessary for instructional effectiveness. The purposes of the study were: a) to assess the knowledge of novice alternatively certified (AC) teachers in the area of autism education; and b) to determine the extent to which age, credit hours of instruction, formal hours of instruction, amount of professional development, and number of students with autism predict the variance in knowledge scores. Participants included all novice (i.e., first-and second-year) alternatively certified special education teachers in the state of Texas. Data were collected through an electronic survey instrument disseminated state-wide to approximately 33 individuals. Multiple regression was conducted in order to determine the strongest predictors of autism knowledge scores. In addition, a multi-way ANOVA was performed to identify differences between groups. The largest predictor of knowledge of autism was hours engaged in self-directed learning. Overall, AC programs in Texas need to provide basic and core content in the area of autism to increase the knowledge of novice teachers. digital.library.unt.edu/ark:/67531/metadc407790/
Bridging the Theory-to-practice Gap: a Multivariate Correlational Study Exploring the Effects of a Graduate Online Learning Environment As a Community of Practice Framework
In this multivariate correlational study, the researcher examined the course culture of an online graduate course whose environment exhibited characteristics of a Community of practice (CoP). An online survey captured data used to explore the relationships among variables shown to describe a CoP in field environments and among student perceptions of their experience in the course culture. A canonical correlation analysis (CCA) and commonality analysis (CA) were conducted using five predictor variables and three criterion variables to evaluate the degree and direction of the relationships. The CCA revealed that the full model was significant, explaining approximately 74% of the variance among the two synthetic variates. Impact, faculty leadership, and connection were the largest contributors to the predictor variate. The criterion variate was primarily explained by value and perceived CoP, with exposure to the profession providing a smaller contribution. The CA confirmed these findings. Results from this study indicate that a CoP could be fostered in an online graduate course. The overall significance of the model indicates teachers can nurture an environment wherein graduate students will take the initiative to work with others to create and acquire knowledge that creates a sense of professional connection with each other and with the profession overall. The results of this study suggest further empirical research in implementing and assessing CoPs in online graduate courses is warranted. digital.library.unt.edu/ark:/67531/metadc407763/
Diaspora Philanthropy: Identity and Obligation Among Indian Engineers in the United States
Diaspora philanthropy to India has grown rapidly over the past several decades. However, little is known about the motivations of Indians living in the U.S. to donate philanthropically to India. Extant studies have either focused on quantitative analysis of diaspora philanthropy or qualitative research on the receiving of diaspora philanthropy in India. The motivations and strategies of the Indian diaspora in the U.S. have not been explored, particularly, the informal mechanisms and strategies of making philanthropic donations to India and the obligations that underlie the practice of diaspora philanthropy remain neglected in the existing studies on diaspora philanthropy. My research addressed this gap in the existing literature on diaspora philanthropy by conducting qualitative face-to-face in-depth interviews with a snowball sample of 25 Indian engineers in San Diego, California. In my study, it was found that Indians preferred to channel funds for philanthropy in India through friends and family because of lack of trust in formal organizations and greater confidence in the activities of friends and family in India due to familiarity and better accountability. It was also found that Indians felt indebted to Indian society and the Indian nation-state for the free and subsidized education they had received in India, and therefore felt obligated to make philanthropic contributions to India in order to redeem the debt that they owe to India. digital.library.unt.edu/ark:/67531/metadc407766/
An Instructional Approach to Introducing Twentieth-century Piano Music to Piano Students From Beginning to Advanced Levels: a Graded Repertoire for Mastering the Challenges Posed by Logan Skelton’s Civil War Variations
Beginning and intermediate piano students typically study the repertoire of the eighteenth and nineteenth centuries. This pedagogical approach leaves them underprepared to approach compositions written since the latter part of the twentieth-century which are significantly different in terms of harmony, rhythm, meter, and compositional procedure. Therefore, a step-by-step method is necessary to prepare a student for the challenges of learning twentieth and twenty-first century piano music. Civil War Variations (1988), by Logan Skelton, is an excellent example of a piece that presents a number of challenges characteristically found in late twentieth-century piano music. The twenty-five variations that comprise the work incorporate a series of twentieth-century musical techniques, namely complex rhythms, extreme dissonance, frequent metric changes, dissonant counterpoint, the inclusion of blues scales and rhythms, and new notations. The purpose of this study is to identify the technical, musical, structural and notational challenges posed by a work such as Logan Skelton’s Civil War Variations; examination of this piece will lead to suggestions regarding repertoire that a teacher may assign to beginning, intermediate, and advanced students in order to prepare them logically and in a step-by-step fashion to cope with and meet the challenges posed by this and other compositions having similar characteristics. digital.library.unt.edu/ark:/67531/metadc407754/
Witchcraft: a Targeted Societal Discrimination Against Women in Northern Ghana
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A combination of aging and poverty is becoming dominant in African society today, at a time when African countries are expected to be recovering from poverty, and are projected to house the economic growth of the next century. The emergence of aging in African context and the aging of the world population will expose the weakness of the current mechanisms used for older people around the world. As economies grow around the world, the distribution gap between the affluent and the poor widens, and the constant struggles for wealth, power, and social status, amidst scarce resources, continue to be sustained. To remain in charge of economic resources, the powerful few devise means to disenfranchise the weak, and witchcraft accusation is one of such tools used in Northern Ghana today. A new wave of witchcraft accusation has caught the attention of many in Northern Ghana. These victims with certain socioeconomic characteristics appear helpless and without defense against such accusations. As a result, they suffer untold hardships and are often compelled to leave their homes and to reside in camps reserved for witches. This study was undertaken to identify those sociodemographic characteristics, which are commonly shared by witchcraft accusation victims. These sociodemographic characteristics can be used to predict those who are most likely to be discriminated against using accusations of witchcraft in Northern Ghana. As age places more strain on existing systems and as more people survive into old age with inadequate healthcare, more accusations may be predicted to occur against the elderly, unless enough government intervention is used to address the present redistribution of income in third world countries. digital.library.unt.edu/ark:/67531/metadc407752/
Nano-crystallization Inhibition in 5 Nm Ru Film Diffusion Barriers for Advanced Cu-interconnect
As the semiconductor industries are moving beyond 22 nm node technology, the currently used stacked Ta/TaN diffusion barrier including a copper seed will be unable to fulfill the requirements for the future technologies. Due to its low resistivity and ability to perform galvanic copper fill without a seed layer, ruthenium (Ru) has emerged as a potential copper diffusion barrier. However, its crystallization and columnar nanostructure have been the main cause of barrier failures even at low processing temperatures (300 oC -350 oC). In this study, we have proposed and evaluated three different strategies to improve the performance of the ultrathin Ru film as a diffusion barrier for copper. The first study focused on shallow surface plasma irradiation/amorphization and nitridation of 5 nm Ru films. Systematic studies of amorphization and nitrogen incorporation versus sample bias were performed. XPS, XRD and RBS were used to determine the physico-chemical, crystallization and barrier efficiency of the plasma modified Ru barrier. The nitrogen plasma surface irradiation of Ru films at substrate bias voltage of -350 V showed an improved barrier performance up to 400 oC annealing temperatures. The barrier barely started failing at 450 oC due mainly to nitrogen instability. The second study involved only amorphization of the Ru thin film without any nitrogen incorporation. A low energy ion beam irradiation/amorphization on Ru thin film was carried out by using 60 KeV carbon ions with different irradiation doses. The irradiation energy was chosen high enough so that the irradiation ions pass through the whole Ru thin film and stop in the SiO2/Si support substrate. The C-ion fluence of 5×1016 atoms/cm2 at 60 KeV made the Ru film near amorphous without changing its composition. XRD and RBS were used to determine the relationship between crystallization and barrier efficiency of the carbon irradiated Ru barrier. The amorphized Ru film showed an improved barrier performance up to 400 oC annealing temperatures similar to the plasma nitrided Ru films. The barrier barely began to fail at 450 oC due mainly to crystallization. The third study focused on a study of Al doping of nitrided Ru thin films and their crystallinity with the aim of obtaining a completely amorphous Ru based barrier and stable nitridation. The addition of 4% Al and 14% of nitrogen in Ru produced a near amorphous film. Nitrogen in the film remained stable until the annealing temperature of 450 oC for 10 min in N2 atmosphere. Crystallization growth of the film was inhibited until 450 oC. At 500 oC, the crystallization of the Ru films barely started, but the degree of its crystallization is minimal. The Ru-Al-N film was demonstrated to be an effective diffusion barrier for copper until the annealing temperature of 450 oC and began to fail at 500 oC. The Al doping was shown to stabilize the nitrogen in the Ru thin film barrier inhibiting its crystallization and leading to improved diffusion barrier performance and a gain in processing temperatures of 150 oC -200 oC over the as prepared pure Ru thin film barriers. digital.library.unt.edu/ark:/67531/metadc407743/
Photochemical and Photophysical Properties of Mononuclear and Multinuclear Closed Shell D10 Coinage Metal Complexes and Their Metallo-organometallic Adducts
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This dissertation covers the studies of two major topics: the photochemistry of mononuclear and multinuclear gold(I) complexes and synthetic approaches to tailor photophysical properties of cyclic trinuclear d10 complexes. First a detailed photochemical examination into the photoreactivity of neutral mononuclear and multinuclear gold(I) complexes is discussed, with the aim of gold nanoparticle size and shape control for biomedical and catalysis applications. Next is a comprehensive systematic synthetic approach to tailor the photophysical properties of cyclic trinuclear d10 complexes. This synthetic approach includes an investigation of structure-luminescence relationships between cyclic trinuclear complexes, an examination into their π-acid/π-base reactivity with heavy metal cations and an exploration into the photophysical properties of new heterobimetallic cyclic trinuclear complexes. These photophysical properties inspections are used to screen materials for their employment in molecular electronic devices such as organic light-emitting diodes (OLEDs) and thin film transistors (OTFTs). digital.library.unt.edu/ark:/67531/metadc407759/
Statistical Strategies for Efficient Signal Detection and Parameter Estimation in Wireless Sensor Networks
This dissertation investigates data reduction strategies from a signal processing perspective in centralized detection and estimation applications. First, it considers a deterministic source observed by a network of sensors and develops an analytical strategy for ranking sensor transmissions based on the magnitude of their test statistics. The benefit of the proposed strategy is that the decision to transmit or not to transmit observations to the fusion center can be made at the sensor level resulting in significant savings in transmission costs. A sensor network based on target tracking application is simulated to demonstrate the benefits of the proposed strategy over the unconstrained energy approach. Second, it considers the detection of random signals in noisy measurements and evaluates the performance of eigenvalue-based signal detectors. Due to their computational simplicity, robustness and performance, these detectors have recently received a lot of attention. When the observed random signal is correlated, several researchers claim that the performance of eigenvalue-based detectors exceeds that of the classical energy detector. However, such claims fail to consider the fact that when the signal is correlated, the optimal detector is the estimator-correlator and not the energy detector. In this dissertation, through theoretical analyses and Monte Carlo simulations, eigenvalue-based detectors are shown to be suboptimal when compared to the energy detector and the estimator-correlator. digital.library.unt.edu/ark:/67531/metadc407740/
Modeling the Effects of Chronic Toxicity of Pharmaceutical Chemicals on the Life History Strategies of Ceriodaphnia Dubia: a Multigenerational Study
Trace quantities of pharmaceuticals (including carbamazepine and sertraline) are continuously discharged into the environment, which causes concern among scientists and regulators regarding their potential long-term impacts on aquatic ecosystems. These compounds and their metabolites are continuously interacting with the orgranisms in various life stages, and may differentially influence development of embryo, larvae, juvenile, and adult stages. To fully understand the potential ecological risks of two candidate pharmaceutical chemicals (carbamazepine (CBZ) and sertraline (SERT)) exposure on survival, growth and reproduction of Ceriodaphnia dubia in three sucessive generations under static renewal toxicity test, a multigenerational approach was taken. Results indicate that SERT exposure showed higher sensitivity to chronic exposure to C. dubia growth and reproduction than CBZ exposure. The lowest concentration to affect fecundity and growth was at 50 µg L-1 SERT in the first two generations. These parameters become more sensitive during the third generation where the LOEC was 4.8 µg L-1. The effective concentrations (EC50) for the number of offspring per female, offspring body size, and dry weight were 17.2, 21.2, and 26.2 µg SERT L-1, respectively. Endpoints measured in this study demonstrate that chronic exposure of C. dubia to SERT leads to effects that occur at concentrations an order of magnitude higher than predicted environmental concentrations indicating potential transgenerationals effects. Additionally, a process-based dynamic energy budget (DEB) model is implemented to predict the simulated effects of chronic toxicity of SERT and CBZ to C. dubia individual behavior at laboratory condition. The model‘s output indicates the ecotoxicological mode of action of SERT exposure, which acts on feeding or assimilation with an effect that rapidly saturates at higher concentrations. Offspring size decreases with the toxic effects on feeding, and offspring number is thus less affected than total investment in reproduction. Consequently, CBZ affects direclty in reproduction which are captured by DEBtox model as increased embryonic hazard and reproduction cost as well as growth and maintenance costs. Furthermore, stress factor linearly increased not only with increasing chemical concentrations but also with exposure time. The DEBtox model establishes a cumulative life history consequence of multigenerational exposure to CBZ and SERT. This approach provides a tool to which to understand the effect of chemical to the individual organism and predict the population level effects in ecological risk assessment of the emerging contaminants. digital.library.unt.edu/ark:/67531/metadc407771/
Investigation of the Pharmacokinetics of Diazepam in Juvenile Channel Catfish (Ictalurus Punctatus)
The presence of pharmaceuticals in the environment is becoming an increasing regulatory and scientific concern. Thus, the metabolic profile and bioconcentration potential of diazepam, a model benzodiazepine, were examined, as well as effects on the endocrine system in channel catfish. Through the use of specific and non-specific cytochrome P450 (CYP450) inhibitors, it was determined that CYP3A-like enzymes may play a role in the biotransformation of diazepam into temazepam; however, the isoform(s) required for the formation of other metabolites is still unknown. Overall, only around 7-8% of diazepam is biotransformed into two known metabolites. Due to the lack of inherent metabolism of diazepam in channel catfish, further analysis was conducted to determine the tissue-specific bioconcentration potential of diazepam in catfish. Various tissues were analyzed for the presence of diazepam as well as metabolites and bioconcentration factors (BCF) were calculated, which were all well below regulatory threshold values (> 2000). Additionally, modulation of the endocrine system by diazepam was examined by measuring steroid hormone concentrations and analyzing mRNA expression of selected steroidogenic enzymes and receptors. Two steroidogenic enzymes were modulated following diazepam exposure, indicating potential endocrine disrupting properties of diazepam. Together, these data suggest that diazepam exhibits low metabolic transformation rates in channel catfish, which may lead to accumulation of benzodiazepine compounds that may negatively affect the endocrine system. However, further studies should be aimed at identifying other steroidogenic enzymes and/or receptors that may be modulated following diazepam exposure. digital.library.unt.edu/ark:/67531/metadc407799/
Maximum Likelihood Estimation of Logistic Sinusoidal Regression Models
We consider the problem of maximum likelihood estimation of logistic sinusoidal regression models and develop some asymptotic theory including the consistency and joint rates of convergence for the maximum likelihood estimators. The key techniques build upon a synthesis of the results of Walker and Song and Li for the widely studied sinusoidal regression model and on making a connection to a result of Radchenko. Monte Carlo simulations are also presented to demonstrate the finite-sample performance of the estimators digital.library.unt.edu/ark:/67531/metadc407796/
A New Era of Educational Assessment: the Use of Stratified Random Sampling in High Stakes Testing
Although sampling techniques have been used effectively in education research and practice it is not clear how stratified random sampling techniques apply to high-stakes testing in the current educational environment. The present study focused on representative sampling as a possible means for reducing the quantity of state-administered tests in Texas public education. The purpose of this study was two-fold: (1) to determine if stratified random sampling is a viable option for reducing the number of students participating in Texas state assessments, and (2) to determine which sampling rate provides consistent estimates of the actual test results among the population of students. The study examined students’ scaled scores, percent of students passing, and student growth over a three-year period on state-mandated assessments in reading, mathematics, science, and social studies. Four sampling rates were considered (10%, 15%, 20%, & 25%) when analyzing student performance across demographic variables, including population estimates by socioeconomic status, limited English proficiency, and placement in special education classes. The data set for this study included five school districts and 68,641 students. Factorial ANOVAs were used initially to examine the effects of sampling rate on bias in reading and mathematics scores and bias in percentage of students passing these tests. Also 95% confidence intervals (CIs) and effect sizes for each model were examined to aid in the interpretation of the results. The results showed main effects for sampling rate and campus as well as a two-way interaction between these variables. The results indicated that a 20% sampling rate would closely approximate the parameter values regarding the mean TAKS reading and mathematics scale scores and the percentage of students passing these assessments. However, as population size decreases, sampling rate may have to be increased. For example, in populations with 30 or fewer students in a subgroup it is recommended that all students be included in the testing program. This study situated in one state contributes to the growing body of research being conducted on an international basis in sample-based educational assessments. digital.library.unt.edu/ark:/67531/metadc407797/
Mexican Mothers’ Experiences with Depression, Intimate Partner Violence, and Immigration: a Mixed Methods Study of Maternal Self-efficacy
This study investigated the relation between maternal self-efficacy, depression, and intimate partner violence among Mexican immigrant and Mexican mothers. The research was conducted using a parallel mixed methods approach including both qualitative and quantitative methods. A total of 136 mothers living in the United States and Mexico completed surveys, and 10 mothers participated in semi-structured interviews. In a regression on maternal depression, living in Mexico as opposed to the U.S., psychological violence, and maternal self-efficacy were significant predictors of maternal depression. In the qualitative data analysis, we found five main themes: perceptions, cultural influence, involvement, resources, and barriers. In this stage of the study, Mexican and Mexican immigrant mothers described in detail their experiences of being a mother, their perceptions of maternal self-efficacy, and the influence of intimate partner violence and depression on their effectiveness as mothers. Overall, Mexican immigrant families appeared to have healthier relationships and greater well-being than Mexican families. digital.library.unt.edu/ark:/67531/metadc407749/
Postoperative Neuropsychological Outcomes in Pediatric Patients Undergoing Temporal Lobe Epilepsy Surgery
The purpose of this study was to investigate the neuropsychological outcomes of pediatric subjects undergoing temporal lobe surgery, and then compare the outcomes between subjects in the iMRI and the standard operating suites. This study involved 77 children ages one to 21 years (M = 11.98) at time of surgery for intractable epilepsy. Forty-seven returned for repeat neuropsychological assessment. At baseline, subjects with early onset of epilepsy (≤ 7 years) scored worse on a measure of attention (p = .02), FSIQ (p < .01), perceptual reasoning (p < .01), and processing speed (p = .06). At one-year follow-up, interactions were observed for the response style domain of the attention measure (p = .03), FSIQ (p = .06) and working memory (p = .08). Follow-up at one year, for the group as a whole, revealed decline in verbal memory (p = .04) and reading comprehension (p = .02); and improvement for word reading (p = .05). No significant differences were observed between the iMRI and standard operating suite. Though, hemisphere, duration of epilepsy, preoperative seizure frequency, lesional disease, seizure type, presence of epileptogenic focus, and number of lobes involved accounted for variance in neuropsychological outcomes. These results provide further support for that certain preoperative individual, disease, and therapeutic variables are predictive of neurocognitive outcome following surgery for temporal lobe epilepsy. Additionally, the results demonstrated that surgery may also impact attention. digital.library.unt.edu/ark:/67531/metadc407806/
A Case Study of 1:1 Technology Policies in Four Texas High Schools and Their Relationship to Practice
With increasing emphasis on technology in schools, the importance of technology policies is great. This study investigated policies for four 1:1 secondary schools in Texas (schools with a ratio of one computing device per student), particularly with respect to the relationship of those policies to practice. The purpose of the study was to determine the current status of the National Education Technology Standards (NETS) essential conditions as reflected in policy and the relationship of those conditions to practice as measured through levels of technology usage and teaching innovation. Schools were selected through purposive, criterion sampling. Open-ended interviews were conducted with twelve participants (principals, technology directors, and superintendents). Policies were rated by campus principals and the researcher using a rubric based on the NETS essential conditions. Finally, surveys of proficiency and readiness measures were collected from 156 teachers using the School Technology and Readiness (STaR) instrument and the Levels of Teaching Innovation (LoTI) instrument. Interviews were transcribed and coded using structural and frequency coding. Policies were analyzed using magnitude coding and policy ratings. A qualitative analysis determined patterns between policy and practice. Quantitative data collected from surveys were measured against policy ratings and magnitude coding using bivariate correlation methods in SPSS. Quantitative analysis revealed two statistically significant relationships between policy and reported levels of practice in the classroom. Qualitative elements of the study from interviews and policy ratings revealed six findings that may explain a lack of correlation between policy and practice: a lack of ability for leadership to identify 1:1 program policy; lack among school leaders of perceived relationship between policy and practice; a belief among leaders that they are communicating policy to stakeholders even though they demonstrated difficulty in articulating policy; an inability to identify specific research-based theoretical foundations in policy; a lack of meaningful measurement of practices; and a lack of leadership at the same school to interpret policy similarly. A seventh finding revealed potential patterns between conditions that are addressed extensively in policy and evidence of those conditions in practice. Qualitative findings, in particular, contribute insights into disconnections between policy and practice in 1:1 settings. digital.library.unt.edu/ark:/67531/metadc407819/
Teacher Communication in Title I Elementary Music Classrooms: Perceptions of Elementary Music Classroom Teachers
The increasing cultural diversity in the United States has brought not only richness, but also complex challenges, to various segments of American society, particularly with regard to public schools. As the student population continues to diversify while teacher population remains predominately White, female, and middle class, teacher awareness in the classroom might be an integral piece to assist students marginalized by stereotypes in feeling more empowered in the school community. Through qualitative data collection and analysis, and framed by Basil Bernstein’s language code theory, this study explored teachers’ perceptions of how classroom interactions, in light of differences in communication, might impact students of different socio-economic backgrounds from the teacher. The findings of this study indicated that the participants expressed a desire to connect with all of their students, regardless of their background. They also discussed challenges that made relationships difficult, such as feelings of disconnect from their Title I students and their families based on differences in home life and background. This dissonance was often difficult for the participants to reconcile due to pressures and difficulties in their teaching situations, such as the large number of students and the scheduling of classes, curricular pressures, and other district expectations such as after-school ensembles. Implications for practicing music teachers and teacher education include ways to understand students’ communities and rethinking ways of approaching relevant terminology in education. digital.library.unt.edu/ark:/67531/metadc407827/
Preschool Teachers’ Knowledge of Children’s Mathematical Development and Beliefs About Teaching Mathematics
Early childhood education emphasizes the need of providing high quality early childhood mathematics programs for preschool children. However, there is little research that examines the importance of preschool children’s mathematical knowledge development and teachers’ beliefs about how to teach mathematics to young children. The purposes of this study were to investigate pre-service and in-service preschool teachers’ knowledge of children’s mathematical development and their beliefs about teaching mathematics in the preschool classroom and also to determine how experience differentiates the two groups. This research employed a non-experimental research design with convenient sampling. Ninety-eight pre-service teachers and seventy-seven in-service preschool teachers participated in the research. The Knowledge of Mathematical Development survey (KMD) and the Beliefs survey were used to investigate possible differences between pre-service and in-service preschool teachers’ knowledge of children’s mathematical development and between their beliefs about teaching mathematics. The findings of this study indicate a statistically significant difference between pre-service teachers and in-service preschool teachers in relation to their knowledge of mathematical development. This finding shows that pre-service teachers’ knowledge of children’s mathematical development is somewhat limited; most pre-service teachers have difficulty identifying the process of preschool children’s development of mathematics skills. A second finding reveals a statistically significant difference between pre-service teachers and in-service preschool teachers in relation to their beliefs about (a) age-appropriateness of mathematics instruction in the early childhood classroom, (b) social and emotional versus mathematical development as a primary goal of the preschool curriculum, and (c) teacher comfort with mathematics instruction. No statistically significant difference was found between pre-service teachers’ and in-service preschool teachers’ beliefs regarding the locus of generation of mathematical knowledge. Both groups believe it is the teacher’s responsibility to intentionally teach mathematics to young children. This result suggests that both pre-service and in-service preschool teachers believe that teachers should play a central role in the teaching of mathematics to preschool children. However, both groups would need appropriate education and training to learn how to teach mathematics to young children. Pre-service and in-service preschool teachers’ varying levels of experiences and different levels of education may help explain why there is a significant difference between their knowledge of mathematical development and beliefs about teaching mathematics. digital.library.unt.edu/ark:/67531/metadc407808/
Transfer Capital and Academic Planning: Facilitating Successful Two- to Four-year Transfer in North Texas
The study of transfer has been historically important and now approaches critical proportions. Current and historical patterns of enrollment and attainment in American higher education combined with the economic, demographic, political, and social realities of the 21st century drive the need for increased research and more effective practice for successful transfer of students from two- to four-year higher education institutions. An emerging theory for framing transfer success is transfer capital, which recommends academic planning, financial aid, and admissions advising as primary interventions to increase the rate and success of transfer. This mixed-methods study examined the academic planning portion of transfer capital to assess the effect of academic planning on the number of hours transferred, number of leveling courses needed, excess hours, and grade point average (GPA). Quantitative assessment measured differences among new transfer students enrolling between Spring 2012 and Fall 2013. Qualitative assessment was conducted with advisors and leadership that were part of the transfer advising program examined in this study. ANOVA indicated significant findings at the .05 level for each variable except GPA. Qualitative findings provided context and primary themes of institutional context, academic planning, financial aid knowledge, and institutional partnerships. Findings provide direction for practice as well as further research. digital.library.unt.edu/ark:/67531/metadc407826/
Origin and Role of Factor Viia
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Factor VII, the initiator of the extrinsic coagulation cascade, circulates in human plasma mainly in its zymogen form, Factor VII and in small amounts in its activated form, Factor VIIa. However, the mechanism of initial generation of Factor VIIa is not known despite intensive research using currently available model systems. Earlier findings suggested serine proteases Factor VII activating protease, and hepsin play a role in activating Factor VII, however, it has remained controversial. In this work I estimated the levels of Factor VIIa and Factor VII for the first time in adult zebrafish plasma and also reevaluated the role of the above two serine proteases in activating Factor VII in vivo using zebrafish as a model system. Knockdown of factor VII activating protease did not reduce Factor VIIa levels while hepsin knockdown reduced Factor VIIa levels. After identifying role of hepsin in Factor VII activation in zebrafish, I wanted to identify novel serine proteases playing a role in Factor VII activation. However, a large scale knockdown of all serine proteases in zebrafish genome using available knockdown techniques is prohibitively expensive. Hence, I developed an inexpensive gene knockdown method which was validated with IIb gene knockdown, and knockdown all serine proteases in zebrafish genome. On performing the genetic screen I identified 2 novel genes, hepatocytes growth factor like and prostasin involved in Factor VII activation. digital.library.unt.edu/ark:/67531/metadc407814/
Miniature Mass Spectrometry: Theory, Development and Applications
As mass analyzer technology has continued to improve over the last fifty years, the prospect of field-portable mass spectrometers has garnered interest from many research groups and organizations. Designing a field portable instrument entails more than the scaling down of current commercial systems. Additional considerations such as power consumption, vacuum requirements and ruggedization also play key roles. In this research, two avenues were pursued in the initial development of a portable system. First, micrometer-scale mass analyzers and other electrostatic components were fabricated using silicon on insulator-deep reactive ion etching, and tested. Second, the dimensions of an ion trap were scaled to the millimeter level and fabricated from common metals and commercially available vacuum plastics. This instrument was tested for use in ion isolation and collision induced dissociation for secondary mass spectrometry and confirmatory analyses of unknowns. In addition to portable instrumentation, miniature mass spectrometers show potential for usage in process and reaction monitoring. To this end, a commercial residual gas analyzer was used to monitor plasma deposition and cleaning inside of a chamber designed for laser ablation and soft landing-ion mobility to generate metal-main group clusters. This chamber was also equipped for multiple types of spectral analysis in order to identify and characterize the clusters. Finally, a portion of this research was dedicated to method development in sample collection and analysis for forensic study. A new method for the analysis of illicit chemistries collected via electrostatic lifting is presented. This method incorporates surface-enhanced Raman microscopy as a prescreening tool for nanoextraction and nanospray ionization mass spectrometry. digital.library.unt.edu/ark:/67531/metadc407824/
Carbon Nanostructure Based Donor-acceptor Systems for Solar Energy Harvesting
Carbon nanostructure based functional hybrid molecules hold promise in solarenergy harvesting. Research presented in this dissertation systematically investigates building of various donor-acceptor nanohybrid systems utilizing enriched single walled carbon nanotube and graphene with redox and photoactive molecules such as fullerene, porphyrin, and phthalocyanine. Design, synthesis, and characterization of the donor-acceptor hybrid systems have been carefully performed via supramolecular binding strategies. Various spectroscopic studies have provided ample information in terms of establishment of the formation of donor-acceptor hybrids and their extent of interaction in solution and eventual rate of photoinduced electron and/or energy transfer. Electrochemical studies enabled construction of energy level diagram revealing energetic details of the possible different photochemical events supported by computational studies carried out to establish the HOMO-LUMO levels in the donor acceptor systems. Transient absorption studies confirmed formation of charge separated species in the donor-acceptor systems which have been supported by electron mediation experiments. Based on the photoelectrochemical studies, IPCE of 8% was reported for enriched SWCNT(7,6)-ZnP donor-acceptor systems. In summary, the present investigation on the various nanocarbon sensitized donor-acceptor hybrids substantiates tremendous prospect, that could very well become the next generation of materials in building efficient solar energy harvesting devices andphotocatalyst. digital.library.unt.edu/ark:/67531/metadc407823/
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