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Statistical Strategies for Efficient Signal Detection and Parameter Estimation in Wireless Sensor Networks (open access)

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 …
Date: December 2013
Creator: Ayeh, Eric
System: The UNT Digital Library
“Sunken Monadnock”: a Composition for Flute, Clarinet, Bassoon, Violin, Violoncello, Electric Guitar, Piano, Percussion, Three Female Vocalists, and Computer (open access)

“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 …
Date: December 2013
Creator: Harris, Joshua Kimball
System: The UNT Digital Library
Shakespeare and Modeling Political Subjectivity (open access)

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 …
Date: December 2013
Creator: Worlow, Christian D.
System: The UNT Digital Library
An Examination of Innovations in Alexander Scriabin’s Late Etudes for Piano (open access)

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.
Date: December 2013
Creator: Lee, Kuo-Ying
System: The UNT Digital Library
Posttraumatic Stress and Neurobehavioral Symptoms (open access)

Posttraumatic Stress and Neurobehavioral Symptoms

The purpose of this study is to examine the structure of neurobehavioral symptoms in service members with physical and/or psychological trauma to determine the diagnostic specificity of these symptoms. Previous literature has demonstrated that orthopedic injured, mild traumatic brain injury (MTBI), and healthy controls shared similar levels of postconcussive symptom complaints, which suggest that postconcussion-like symptoms are not unique to MTBI. To the best of my knowledge, this is the first study examining this phenomenon in a sample of recently redeployed service members. Dimensional analysis of the PCL-C and NSI using SEM did not produce a model that was consistent with previous literature and principle component analyses did not produce a simple solution for posttraumatic stress or neurobehavioral symptoms. Thus, the study does not provide evidence for construct validity for either instrument. Implications for these findings are that clinicians need to be aware that these instruments may not be measuring coherent constructs within this population as purported and should judiciously interpret and report the results of these instruments.
Date: December 2013
Creator: Klein, Robert S.
System: The UNT Digital Library
Light, Bright, and Out of Sight: Hollywood’s Representation of the Tragic Mulatto (open access)

Light, Bright, and Out of Sight: Hollywood’s Representation of the Tragic Mulatto

The purpose of this research is to examine the longevity of the stereotype of the tragic mulatto in American film history. Specifically, my research focuses on the portrayals and perceptions of biracial actresses. Media informs, entertains, and influences how we, and especially youth, self-identify and interact with others. This research focuses on the portrayal of biracial actresses throughout film history. It is also important in its investigation of the perpetuation of the one-drop rule. In this research, I will examine if historical stereotypes of tragic mulatto are apparent in contemporary Hollywood film. The methodologies used in this research include a content analysis of films with biracial actresses and an online survey of respondents’ perceptions of four actresses. Statistical techniques used for analysis include ordinary least square regression and multinomial logistic regression. Findings suggest that the tragic mulatto stereotype is not blatant in contemporary Hollywood film, but issues of colorism may be apparent.
Date: December 2013
Creator: Brunson, Alicia
System: The UNT Digital Library
Correlates of Depression in Elderly Asians in the United States (open access)

Correlates of Depression in Elderly Asians in the United States

The primary purpose of this study was to examine the correlation between depression and the personal characteristics of Asians who are 50 years or older. The secondary objective was to determine whether Asians 50 years or older living in the United States are more likely to be depressed than other ethnicities. The information for this study was secured from the National Health Interview Survey, spanning the years 2001 to 2010. In this study, I utilized the SAS-Callable SUDAAN statistical system. Multivariate regression was used to predict and determine significant correlations. The results indicated that Asians 50 and older living in the U.S. and who experience functional limitations, poor vision, hypertension, poor health, not married, and unemployed in previous year were in general more prone to depression. Furthermore, the study indicated that Asian elderly living the U.S. showed lower rates of depression than all non- Asian ethnicities. However when controlled for personal characteristics only Whites and Hispanics had higher depression incidences than Asian elderly. Recommendations for future studies include: conducting more micro and macro studies of Asian elders, such as in-depth case studies for each ethnicity, longitudinal studies of various Asian subgroups, and studies of Asian elderly with hypertension who have …
Date: December 2013
Creator: Kung, Kevin Hsiang-Hsing
System: The UNT Digital Library
Performer’s Guide to the Execution and Application of Karen Tuttle’s Coordination, As Applied to Ernest Bloch’s Suite Hébraïque (open access)

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.
Date: December 2013
Creator: Sander, Amber
System: The UNT Digital Library
Examining High School Coaches’ Likelihood to Refer To, Interest in Working With, and Plans to Hire a Sport Psychologist (open access)

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 …
Date: December 2013
Creator: Austin, Harlan
System: The UNT Digital Library
Diaspora Philanthropy: Identity and Obligation Among Indian Engineers in the United States (open access)

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, …
Date: December 2013
Creator: Batra, Shikha
System: The UNT Digital Library
Transfer Capital and Academic Planning: Facilitating Successful Two- to Four-year Transfer in North Texas (open access)

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 …
Date: December 2013
Creator: O’Keefe, Lynette M.
System: The UNT Digital Library
Teacher Communication in Title I Elementary Music Classrooms: Perceptions of Elementary Music Classroom Teachers (open access)

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 …
Date: December 2013
Creator: Mason, Lindsey Lea
System: The UNT Digital Library
Web Information Behaviors of Users Interacting with a Metadata Navigator (open access)

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 …
Date: December 2013
Creator: McMillan, Tyson DeShaun
System: The UNT Digital Library
The Effect of Stock Splits on Small, Medium, and Large-sized Firms Before and After Decimalization (open access)

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.
Date: December 2013
Creator: Jang, Seon Deog
System: The UNT Digital Library
Maximum Likelihood Estimation of Logistic Sinusoidal Regression Models (open access)

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
Date: December 2013
Creator: Weng, Yu
System: The UNT Digital Library
Churches, Social Service Access and Korean-american Elders: an Exploratory Study (open access)

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 …
Date: December 2013
Creator: Kim, Eunkyung
System: The UNT Digital Library
Witchcraft: a Targeted Societal Discrimination Against Women in Northern Ghana (open access)

Witchcraft: a Targeted Societal Discrimination Against Women in Northern Ghana

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 …
Date: December 2013
Creator: Atumah, Oscar Nwagbo
System: The UNT Digital Library
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 (open access)

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 …
Date: December 2013
Creator: Kim, Dajeong
System: The UNT Digital Library
Dynamic Adhesion and Self-cleaning Mechanisms of Gecko Setae and Spatulae (open access)

Dynamic Adhesion and Self-cleaning Mechanisms of Gecko Setae and Spatulae

Geckos can freely climb on walls and ceilings against their body weight at speed of over 1ms-1. Switching between attachment and detachment seem simple and easy for geckos, without considering the surface to be dry or wet, smooth or rough, dirty or clean. In addition, gecko can shed dirt particles during use, keeping the adhesive pads clean. Mimicking this biological system can lead to a new class of dry adhesives for various applications. However, gecko’s unique dry self-cleaning mechanism remains unknown, which impedes the development of self-cleaning dry adhesives. In this dissertation we provide new evidence and self-cleaning mechanism to explain how gecko shed particles and keep its sticky feet clean. First we studied the dynamic enhancement observed between micro-sized particles and substrate under dry and wet conditions. The adhesion force of soft (polystyrene) and hard (SiO2 and Al2O3) micro-particles on soft (polystyrene) and hard (fused silica and sapphire) substrates was measured using an atomic force microscope (AFM) with retraction (z-piezo) speed ranging over 4 orders of magnitude. The adhesion is strongly enhanced by the dynamic effect. When the retraction speeds varies from 0.02 µm/s to 156 µm/s, the adhesion force increases by 10% ~ 50% in dry nitrogen while …
Date: December 2013
Creator: Xu, Quan
System: The UNT Digital Library
A Comparison of Three Teacher Evaluation Methods and the Impact on College Readiness (open access)

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 …
Date: December 2013
Creator: Smalskas, Tamy L.
System: The UNT Digital Library
Field and Laboratory Fish Tissue Accumulation of Carbamazepine and Amiodarone (open access)

Field and Laboratory Fish Tissue Accumulation of Carbamazepine and Amiodarone

The goals of this dissertation work were to assess the bioaccumulation potential of carbamazepine and amiodarone, two widely used ionizable pharmaceutical compounds that possess mid-range and high LogD values, respectively, and to evaluate alternative methods to assess chemical accumulation in bluntnose minnows, catfish, and tilapia. Results indicated that carbamazepine does not appreciably bioaccumulate in fish tissue with BCFk and BAF carbamazepine values < 10. Amiodarone, however, with a log D of 5.87 at pH 7.4, accumulated in fish tissues with kinetic BCF values <2,400. Collectively, the data suggest that full and abbreviated laboratory-derived BCFs, BCFMs derived from S9 loss-of-parent assays, as well as field BAF values are similar for each of the two drugs. In summary, the results from this dissertation indicated: 1) The reduced design BCF test is a good estimate for the traditional OECD 305 test. 2) In vitro S9 metabolism assays provide comparable BCF estimates to the OECD 305 test. 3) Metabolism may play a large role in the accumulation of drugs in fish. 4) Reduced BCF tests and in vitro assays are cost effective and can reduce vertebrate testing.
Date: December 2013
Creator: García Martínez, Santos Noé
System: The UNT Digital Library
American Indian Worldviews, Risk Perceptions and Disaster Planning: an Exploratory Study (open access)

American Indian Worldviews, Risk Perceptions and Disaster Planning: an Exploratory Study

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.
Date: December 2013
Creator: Bales, Rodney A.
System: The UNT Digital Library
Adolescent Behavior Problems and Interparental Conflict: the Moderating Role of Parent-child Attachment (open access)

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.
Date: December 2013
Creator: Daubs, Carlyn
System: The UNT Digital Library
Integrated Computational and Experimental Approach to Control Physical Texture During Laser Machining of Structural Ceramics (open access)

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 …
Date: December 2013
Creator: Vora, Hitesh D.
System: The UNT Digital Library