Degree Level

States

Language

Latent Transition Analysis of Pre-service Teachers' Efficacy in Mathematics and Science (open access)

Latent Transition Analysis of Pre-service Teachers' Efficacy in Mathematics and Science

This study modeled changes in pre-service teacher efficacy in mathematics and science over the course of the final year of teacher preparation using latent transition analysis (LTA), a longitudinal form of analysis that builds on two modeling traditions (latent class analysis (LCA) and auto-regressive modeling). Data were collected using the STEBI-B, MTEBI-r, and the ABNTMS instruments. The findings suggest that LTA is a viable technique for use in teacher efficacy research. Teacher efficacy is modeled as a construct with two dimensions: personal teaching efficacy (PTE) and outcome expectancy (OE). Findings suggest that the mathematics and science teaching efficacy (PTE) of pre-service teachers is a multi-class phenomena. The analyses revealed a four-class model of PTE at the beginning and end of the final year of teacher training. Results indicate that when pre-service teachers transition between classes, they tend to move from a lower efficacy class into a higher efficacy class. In addition, the findings suggest that time-varying variables (attitudes and beliefs) and time-invariant variables (previous coursework, previous experiences, and teacher perceptions) are statistically significant predictors of efficacy class membership. Further, analyses suggest that the measures used to assess outcome expectancy are not suitable for LCA and LTA procedures.
Date: December 2009
Creator: Ward, Elizabeth Kennedy
System: The UNT Digital Library
Level Curves of the Angle Function of a Positive Definite Symmetric Matrix (open access)

Level Curves of the Angle Function of a Positive Definite Symmetric Matrix

Given a real N by N matrix A, write p(A) for the maximum angle by which A rotates any unit vector. Suppose that A and B are positive definite symmetric (PDS) N by N matrices. Then their Jordan product {A, B} := AB + BA is also symmetric, but not necessarily positive definite. If p(A) + p(B) is obtuse, then there exists a special orthogonal matrix S such that {A, SBS^(-1)} is indefinite. Of course, if A and B commute, then {A, B} is positive definite. Our work grows from the following question: if A and B are commuting positive definite symmetric matrices such that p(A) + p(B) is obtuse, what is the minimal p(S) such that {A, SBS^(-1)} indefinite? In this dissertation we will describe the level curves of the angle function mapping a unit vector x to the angle between x and Ax for a 3 by 3 PDS matrix A, and discuss their interaction with those of a second such matrix.
Date: December 2009
Creator: Bajracharya, Neeraj
System: The UNT Digital Library
An Evaluation Model for Identifying Lewisville and San Angelo, Texas, as Senior Ready Communities (open access)

An Evaluation Model for Identifying Lewisville and San Angelo, Texas, as Senior Ready Communities

This research portrays a paradigm for the assessment of aging services to support populations aging in place. The dissertation was designed to establish a model to identify and evaluate senior ready communities. Area specific social programs and services are identified. In order to meet the growing needs of aging populations, the dynamic representation of existing services and the need for services that could be developed in certain communities require reevaluation in current planning, restructuring, and/or community development.
Date: December 2009
Creator: Sanders, David N.
System: The UNT Digital Library
An Investigation Into the Factors Leading to the Closure of 40 Private Four-Year Colleges between 1965 and 2005 (open access)

An Investigation Into the Factors Leading to the Closure of 40 Private Four-Year Colleges between 1965 and 2005

This study searches for a set of common indicators that contributed to the ultimate closure of 40 colleges and universities between 1965 and 2005. From research on related literature, a set of 31 contributing factors was identified by published experts and observers in higher education. That set of indicators was then used as a list of 31 questions answered by data found in newspaper articles, professional journals, published research work, published institutional records, data taken from the Department of Education, data taken from IPEDS, data published in historical recounts of the colleges of interest, etc. The data was accumulated in the form of yes/no responses to the 31 questions. Although the study involved only 40 colleges and universities this population represents the majority of institutions that pass the restrictions of limitations and delimitations described in the full document. The complete data set was processed using SPSS which produced ANOVA tables and level of statistical significance for each indicator question. The results indicate that out of the 31 original indicator questions there were two groups of statistically significant indicators. The larger group of indicators having statistical significance at the .05 level encompassed the smaller group having statistical significance at the .001 …
Date: December 2009
Creator: Province, Terry Paul
System: The UNT Digital Library
Health Status and Access Disparities Among the Uninsured Working-Age Population in a Safety-Net Healthcare Network in Tarrant County, Texas (open access)

Health Status and Access Disparities Among the Uninsured Working-Age Population in a Safety-Net Healthcare Network in Tarrant County, Texas

The objective of this research was to determine if healthcare access disparities exist across race and gender in a publically funded safety-net healthcare system in Texas. Data were examined from a representative random sample of 1468 adults aged 18-64 who were patients in this safety-net system in July and August of 2000 and were analyzed using binary logistic regression and chi-square measures of significance. Major Findings: On measures of health status - overall health rating (p =.051), limited employment (p =.000), energy level (p =.001), and worry (p =.012) - Anglos reported the worst health; Mexican Americans, the best health; with African Americans intermediate. Mexican Americans were more likely to have never had health insurance, and to also have had insurance in the past year; Anglos were least likely to have ever had insurance (p =.015) or to have had insurance in the past year (p =.000). On use of EDs (p =.028), problems getting prescription medicines (p =.029), and foregoing other necessities of life to pay for healthcare, Mexican Americans were least disadvantaged with African Americans reporting greatest use of EDs among both men and women, and Anglos the most problems with prescription medicines and foregoing care, especially among …
Date: December 2009
Creator: Queen, Courtney M.
System: The UNT Digital Library
The Effects of Attendance at a Senior Center on the Quality of Life and Well Being of Grandparents Rearing Grandchildren. (open access)

The Effects of Attendance at a Senior Center on the Quality of Life and Well Being of Grandparents Rearing Grandchildren.

The purpose of this study was to determine the effects of attendance at a senior center on the well being and quality of life of grandparents that were rearing grandchildren. Using convenience sampling, grandparents (N=130) who were rearing grandchildren were given a self administered demographic data survey along with an attendance at a senior center questionnaire, the Quality of Life Scale, the Well Being Scale by Liang, the UCLA Loneliness Scale, the Caregiver Burden Scale, and the Role Satisfaction Scale. An initial MANOVA (F 7, 69 = 2.72, p < .01) suggesting that senior center attendance affect the measures as a set was conducted and then a series of one way ANOVAs were carried out to test the hypothesis that attending a senior center has an effect on the dependent variables: well being, quality of life, role satisfaction, caregiver burden, loneliness, current health, and heath one year ago. Subsequently, a hierarchical regression analysis was conducted to find out whether frequency and quality of attendance of a senior center predicted quality of life, caregiver burden, well being, loneliness, and role satisfaction, controlling for the demographic data. The results of the MANOVA showed that the dependent variables: quality of life, caregiver burden, …
Date: December 2009
Creator: Rhynes, LaTrica Q.
System: The UNT Digital Library
The Effects of Pre-Kindergarten on Spanish-Speaking Bilingual Students Taking the Third Grade TAKS Reading Test (open access)

The Effects of Pre-Kindergarten on Spanish-Speaking Bilingual Students Taking the Third Grade TAKS Reading Test

The purpose of this dissertation is to provide research and data examining the impact of pre-kindergarten on Spanish-speaking ESL students on the third grade TAKS Reading test scores. The two questions that guided this study are: (1) As measured by the third grade TAKS reading test, what is the relationship between those limited english proficient (LEP) Spanish-speaking children who attended a pre-kindergarten program and those who did not attend a pre-kindergarten program? and (2) As measured by the third grade TAKS Reading test, how do the test scores of those LEP Spanish-speaking third graders who attended the district's pre-k program in 2000-2001 and testing in 2005, differ from those who attended the district's pre-k program in 2001-2002 and testing in 2006? The research study used a quantitative methodology designed as causal-comparative analysis. Independent t-tests were used to determine if there were any significant differences in test scores of third graders between the two groups of students. Although the results of the statistical analysis revealed some isolated statistically significant differences between those Spanish-speaking bilingual students who attended pre-kindergarten and those who did not, the data showed no real differences in the test scores of those students.
Date: December 2008
Creator: Ringhauser, John T.
System: The UNT Digital Library
Victimization and expressions of relational and overt aggression among boys and girls with ADHD. (open access)

Victimization and expressions of relational and overt aggression among boys and girls with ADHD.

This study investigated if girls and boys high in ADHD symptomology exhibited and experienced relational and overt aggression differently than boys and girls without ADHD symptoms using peer, parent and teacher ratings. A measurement of social behavior for parent ratings was also validated. Using archival data, 371 3rd- 6th graders from a north Texas school district participated in the study, along with a parent or guardian and teachers. Results supported that ADHD subtype predicted more overt aggression according to parents and teachers but not peers. ADHD subtype did not predict more relational aggression but ADHD symptomology did. Contrary to past research, gender did not moderate relational aggression or internalizing symptoms from relational victimization. Furthermore, a parent version of the Child Social Behavior Scale was found to effectively measure relational, overt and prosocial behavior. Limitations, future directions and implications are discussed.
Date: December 2009
Creator: Rivero, Arlene Jean Abello
System: The UNT Digital Library
Inferring Social and Internal Context Using a Mobile Phone (open access)

Inferring Social and Internal Context Using a Mobile Phone

This dissertation is composed of research studies that contribute to three research areas including social context-aware computing, internal context-aware computing, and human behavioral data mining. In social context-aware computing, four studies are conducted. First, mobile phone user calling behavioral patterns are characterized in forms of randomness level where relationships among them are then identified. Next, a study is conducted to investigate the relationship between the calling behavior and organizational groups. Third, a method is presented to quantitatively define mobile social closeness and social groups, which are then used to identify social group sizes and scaling ratio. Last, based on the mobile social grouping framework, the significant role of social ties in communication patterns is revealed. In internal context-aware computing, two studies are conducted where the notions of internal context are intention and situation. For intentional context, the goal is to sense the intention of the user in placing calls. A model is thus presented for predicting future calls envisaged as a call predicted list (CPL), which makes use of call history to build a probabilistic model of calling behavior. As an incoming call predictor, CPL is a list of numbers/contacts that are the most likely to be the callers within …
Date: December 2009
Creator: Phithakkitnukoon, Santi
System: The UNT Digital Library
Does the Knowledge of Unaudited Account Balances Adversely Affect the Performance of Substantive Analytical Procedures? (open access)

Does the Knowledge of Unaudited Account Balances Adversely Affect the Performance of Substantive Analytical Procedures?

Auditors use substantive analytical procedures to make assertions about the adequacy and appropriateness of client balances. The analytical procedure process consists of auditors creating independent account expectations and corroborating unusual fluctuations through obtaining and evaluating additional audit evidence. Prior analytical procedure research has found that knowledge of clients' unaudited account balances biases auditors' expectations towards the current year figures. However, this research has failed to examine the impact of biased expectations on the subsequent stages of analytical procedures. This dissertation assesses the full impact of biased account expectations on auditors' use of analytical procedures. I experimentally test the hypotheses of my dissertation through administering an experiment to senior level auditors. After inducing an account expectation bias that favors the client account balance in half the participants, I examine the auditors' cognitive investigation into an unusual account fluctuation. The results indicate that a biased account expectation negatively affects auditors' judgment quality. In particular, a biased expectation leads auditors to favor hypotheses and additional information that supports the proposition that the client's balance is reasonably stated. Alternatively, auditors with unbiased account expectations are more willing to consider all hypotheses and are able to identify the most pertinent additional information to the decision …
Date: December 2009
Creator: Pike, Byron J.
System: The UNT Digital Library
The perception of English language arts teachers about instructional changes following the implementation of the Texas Assessment of Knowledge and Skills test. (open access)

The perception of English language arts teachers about instructional changes following the implementation of the Texas Assessment of Knowledge and Skills test.

Accountability in education has been expanding for the past twenty years. As standards for curricular areas continued to develop, educational shareholders desired a way to measure student achievement contextualized by the established standards. Since 1964, policies expanded federal involvement with education, and with the No Child Left Behind Act in 2001, high-stakes testing became a significant part of public education. In Texas, testing transitioned in 2003 to the Texas Assessment of Knowledge and Skill (TAKS) test, an assessment that determines grade advancement for students, ratings for school districts, and additional compensation for some teachers. Along with the increasing expectations for student achievement, the need for effective instruction also increases. This dissertation studies how English language arts (ELA) teachers in four North Texas suburban high schools perceive instructional change following the implementation of TAKS. One hundred twenty-one teachers (n=121) were surveyed using an instrument broken into seven categories: student-centered instruction, student interest, instructional communication, time, classroom environment, teacher knowledge, and assessment. Participants were separated into two groups, teachers with one to six years of experience with a district or seven or more years with a district. Using a rating scale for each statement on the survey instrument, participants indicated the direction …
Date: December 2009
Creator: Horn, Brian K.
System: The UNT Digital Library
The relationship of student characteristics, help seeking behavior, academic and environmental variables with student course completion in community college online courses: An application of a conceptual model. (open access)

The relationship of student characteristics, help seeking behavior, academic and environmental variables with student course completion in community college online courses: An application of a conceptual model.

The purpose of this study was to examine differences and relationships in student definition and background characteristics, help seeking behaviors, academic and environmental variables between and among community college students at a single institution who successfully completed and those who did not complete online courses during a single term. An adapted version of Bean and Metzner's conceptual model of nontraditional student attrition provided the theoretical framework for the study. The results of data analysis revealed statistically significant differences between completers and noncompleters on the basis of definition, gender, ethnicity, experience and prior GPA. Statistically significant relationships were found between definition, ethnicity, gender, experience, prior GPA, orientation and completion and noncompletion. No statistically significant interactions were found between definition and experience and help seeking behaviors. No statistically significant differences, relationships or predictor variables were found by degree seeking, preassessment, or technical help seeking. Additional analyses by defining characteristics revealed statistically significant differences between completers and noncompleters on the basis of residency, age and enrollment status. Predictor variables found to be significant were definition, gender, experience, prior GPA and orientation. The odds of completion increased with nontraditional definition, female gender, higher prior GPA, and orientation participation. The odds of completion decreased with …
Date: December 2009
Creator: Schumann, Sherry Haskin
System: The UNT Digital Library
Phosphorescent Emissions of Coinage Metal-Phosphine Complexes: Theory and Photophysics (open access)

Phosphorescent Emissions of Coinage Metal-Phosphine Complexes: Theory and Photophysics

The major topics discussed are all relevant to the bright phosphorescent emissions of coinage metal complexes (Cu(I), Ag(I) and Au(I)) with an explanation of the theoretical background, computational results and ongoing work on the application in materials and optoelectronic devices. Density functional computations have been performed on the majority of the discussed complexes and determined that the most significant distortion that occurs in Au(I)-phosphine complexes is a near and beyond a T-shape within the P-Au-P angle when the complexes are photoexcited to the lowest phosphorescent excited state. The large distortion is experimentally qualified with the large Stokes' shift that occurs between the excitation and emission spectra and can be as large as 18 000 cm-1 for the neutral Au(I) complexes. The excited state distortion has been thoroughly investigated and it is determined that not only is it pertinent to the efficient luminescence but also for the tunability in the emission. The factors that affect tunability have been determined to be electronics, sterics, rigidity of solution and temperature. The luminescent shifts determined from varying these parameters have been described systematically and have revealed emission colors that span the entire visible spectrum. These astounding features that have been discovered within studies of …
Date: December 2009
Creator: Sinha, Pankaj
System: The UNT Digital Library
Bidirectional Effects Between Engaged Lifestyle and Cognition in Later Life: Exploring the Moderation Hypothesis for Personality Variables. (open access)

Bidirectional Effects Between Engaged Lifestyle and Cognition in Later Life: Exploring the Moderation Hypothesis for Personality Variables.

Longitudinal data (N = 263) was used to investigate the bidirectional relationship between engagement (engaged lifestyle activities) and cognition (crystallized & fluid intelligence). Extroversion and openness to experience were also tested as moderators of the relationship between engagement and cognition. Results showed that the relationship between engagement at Wave 1 and cognition at Wave 2 did not differ from the relationship between cognition at Wave 1 and engagement at Wave 2. Testing for moderation with regression indicated that neither extroversion nor openness was moderating the relationship between engagement and cognition in either direction. Structural equation models provided further summary evidence that the relationships among engagement at Wave 1, extroversion, openness, and cognition at Wave 2 were not strong. However, a strong limitation to these results was the measurement error associated with a new measure of engagement.
Date: December 2009
Creator: Starkweather, Jonathan
System: The UNT Digital Library
Cultural and Technical Perspectives on Winter Landscape (open access)

Cultural and Technical Perspectives on Winter Landscape

Winter Landscape is an interactive composition for erhu (Chinese two-stringed fiddle), flute, piano, and Max/MSP interactive computer music system. The total duration of the piece is approximately 15 minutes. Winter Landscape serves to demonstrate one particular approach to exploring the possibilities afforded in an interactive paradigm within a cross-cultural context. The work is intended to convey my personality and identity as a contemporary Chinese composer through diverse cultural and musical influences drawn to this particular piece while creating a balance between traditional and modern sounds. The influences of Chinese philosophy (especially Chán) and the essence of Chinese traditional music play a prominent role as demonstrated in the formation of structures, expressions, and concept of Yun in the work; these influences also play a great role in determining the instrumentation and basic pitch structures of the work. However, this work is equally influenced by techniques and practices of modern Western classical music. These diverse influences hopefully have resulted in a unique work that truly does represent a cross-synthesis of these varying influences. In Winter Landscape, the interaction that takes place between the computer and the live musician is intended to reveal the responsive human/machine relationships. The computer constantly shifts its roles …
Date: December 2009
Creator: Wang, Jing
System: The UNT Digital Library
Cyberbullying: Responses of Adolescents and Parents toward Digital Aggression (open access)

Cyberbullying: Responses of Adolescents and Parents toward Digital Aggression

Cyberbullying is a category of bullying that occurs in the digital realm which affects our students at astonishing rates. Unlike traditional bullying, where displays of aggression may be evident to bystanders, the ramification of cyberbullying occurs through unconventional ways (e.g., text messaging; online weblogs; video sharing), which results in many cases being camouflaged by the advancement in technology. Nonetheless, the effects of this digital form of peer aggression can be as detrimental as face-to-face bullying. The characteristics of cyberbullying and its influences on adolescents and parents of adolescents were examined. The data accrued is based on an anonymous survey through one of the following methods: (a) paper-pencil survey for adolescent group with 37-question items on the adolescent questionnaire and (b) web-based survey for the parent group with 22-question items on the parent questionnaire. Each survey was systematically coded according to the participating group and assigned code numbers (i.e., 1 represents adolescent group and 2 represents parent group) was provided to ensure confidentiality of the study. Survey examined individual variables among the two target groups: (a) adolescents between 13 and 17 years of age and (b) parents of adolescents between 13 and 17 years of age. Specifically, individual variables examined include …
Date: December 2009
Creator: Wong-Lo, Mickie
System: The UNT Digital Library
The relationship between computer-assisted instruction and alternative programs to enhance fifth-grade mathematics success on the annual Texas Assessment of Knowledge and Skills. (open access)

The relationship between computer-assisted instruction and alternative programs to enhance fifth-grade mathematics success on the annual Texas Assessment of Knowledge and Skills.

The purpose of this study was to determine the relationship between using computer-assisted instruction (CAI) and success on the Texas Assessment of Knowledge and Skills (TAKS) mathematics exam with fifth-grade students in Texas compared to the effect of alternative improvement approaches used by a control group. Research explored the use of SuccessMaker® CAI educational software (Pearson Education, Upper Saddle River, NJ, www.pearsoned.com) in public elementary schools in Texas. Successmaker® CAI was not a good predictor of passing percentage on the mathematics TAKS. Multiple regression analysis utilized in this quasi-experimental design study predicted a negative and not statistically significant change in the percentage of students passing the mathematics TAKS exam (B = -.448, p > .05). SuccessMaker® use exhibited a very small effect size (r = -.04) and accounted for less than 1% of the change in passing percentage (r2 = .0016). Multiple regression model predicted a negative and statistically significant effect upon mathematics passing percentage by economic disadvantage percentage (B = -.211, p < .01). The 95% confidence interval for B ranged from -.365 to -.057. The large effect size correlation coefficient (r = -.51) accounted for 26% of the variance in the mathematics TAKS passing percentage (r2 = .26).
Date: December 2009
Creator: Tucker, Tommy Howard
System: The UNT Digital Library
The Impact of Surveillance Technology on the Behaviors of Municipal Police Departments (open access)

The Impact of Surveillance Technology on the Behaviors of Municipal Police Departments

Citizen complaints about inappropriate use of force indicate negative police-public relations, unresponsive police services, and the unresponsiveness of police management to citizens' concerns. However, the effective delivery of key policing services depends on the performance of individual police officers. Surveillance technology can monitor and control the behavior of officers, ensuring that police officers provide high quality policing services that meet the needs of citizens. Examples of surveillance technology such as in-car cameras and CCTV can be used as an administrative tool to respond to citizen complaints by police chief executives. This research examines the effect of surveillance technology on the behavior of municipal police departments that is operationalized as the number of citizen complaints that were filed against municipal police departments. This research also examines the impact of surveillance technology on dismissed and sustained complaints by using 511 large municipal police departments in the U.S. from Law Enforcement Management and Administrative Statistics (LEMAS) 2003 dataset. Three different models are developed to evaluate the impact of in-car cameras and CCTV on the citizen complaints and their dispositions. Two ordinary least square regression (OLS) models and a Heckman selection model are used to analyze the data. The Heckman selection model is utilized …
Date: December 2009
Creator: Ulkemen, Sinan
System: The UNT Digital Library
Perceived Racial Discrimination and Psychiatric Outcomes among Asian Americans (open access)

Perceived Racial Discrimination and Psychiatric Outcomes among Asian Americans

The present study related generational status, family dynamics, and perceptions of racial discrimination (PRD) to acute psychiatric outcomes among a nationally representative Asian American sample (N = 2095), using data from the National Latino and Asian American Study (NLAAS). High self-reports of PRD were correlated with endorsement of clinical depression and suicidality as predicted. Regression analyses suggested that high PRD, low family cohesion, and high family conflict served as significant predictors of poor mental health independently, but moderator hypotheses predicting the interaction of these factors were not supported. Clinical and research implications are provided.
Date: December 2009
Creator: Varghese, Anita
System: The UNT Digital Library
The Impact of Legal Sanctions on Recidivism Rates among Male Perpetrators of Domestic Violence (open access)

The Impact of Legal Sanctions on Recidivism Rates among Male Perpetrators of Domestic Violence

Using a Cox proportional hazards regression model, this dissertation explores three factors currently not addressed in the literature on men who batter women and who are court ordered to participate in a battering intervention program. These factors are the cumulative effects of civil and criminal legal sanctions (dose-response of sanctions) for domestic violence related offenses on recidivism, reduced opportunities to recidivate, and whether the number of legal sanctions imposed has an effect on how long a man maintains his non-recidivism status. Because one domestic violence case may involve multiple sanctions, this study uses the Legal Sanction Dose-Response Index to gauge the cumulative impact of civil and criminal sanctions upon recidivism of domestic violence. The Cox proportional hazards model indicates that the risk of recidivism is 45% lower for men who experienced two legal sanctions (typically arrest and probation) in response to the index case, relative to men who experienced one legal sanction (typically civil protective order). In other words, those with two legal sanctions are able to maintain their non-recidivism status longer relative to those with one sanction. Men with prior criminal court involvement for domestic violence related offenses are more likely to recidivate. Additionally, rather than incarceration reducing opportunities …
Date: December 2009
Creator: Cosimo, S. Deborah
System: The UNT Digital Library
The Value of Everything: Ranking and Association with Encyclopedic Knowledge (open access)

The Value of Everything: Ranking and Association with Encyclopedic Knowledge

This dissertation describes WikiRank, an unsupervised method of assigning relative values to elements of a broad coverage encyclopedic information source in order to identify those entries that may be relevant to a given piece of text. The valuation given to an entry is based not on textual similarity but instead on the links that associate entries, and an estimation of the expected frequency of visitation that would be given to each entry based on those associations in context. This estimation of relative frequency of visitation is embodied in modifications to the random walk interpretation of the PageRank algorithm. WikiRank is an effective algorithm to support natural language processing applications. It is shown to exceed the performance of previous machine learning algorithms for the task of automatic topic identification, providing results comparable to that of human annotators. Second, WikiRank is found useful for the task of recognizing text-based paraphrases on a semantic level, by comparing the distribution of attention generated by two pieces of text using the encyclopedic resource as a common reference. Finally, WikiRank is shown to have the ability to use its base of encyclopedic knowledge to recognize terms from different ontologies as describing the same thing, and thus …
Date: December 2009
Creator: Coursey, Kino High
System: The UNT Digital Library
Negative affect and positive symptoms of psychosis. (open access)

Negative affect and positive symptoms of psychosis.

The current study utilized structural equation modeling (SEM) to examine the factor-to-factor relations and temporal associations between disturbances in negative affect (NA) and positive symptoms of psychosis (PP). Data were drawn from a large, public-domain data set (MacArthur Violence Risk Assessment Study). A dimensional approach was used to conceptualize and identify latent variables of NA (depression, anxiety, and guilt) and PP (hallucinations, delusions, and thought disorder) among individuals with a diagnosis of primary psychotic disorder. Results showed that anxiety, guilt, and depressed mood modeled an NA latent variable, and that hallucinations and unusual thought content modeled a PP latent variable. As predicted, results revealed strong, significant cross-sectional (synchronous) associations between NA and PP at each measured time-frame, suggesting that NA and PP occurred concurrently within the sample. Contrary to predictions, no significant cross-lagged effect between NA and PP was identified (10 weeks and 20 weeks respectively).
Date: December 2009
Creator: Crutchfield, Audra
System: The UNT Digital Library
The Effectiveness of Business Leadership Practices among Principals on Student Achievement on Public School Campuses in Texas (open access)

The Effectiveness of Business Leadership Practices among Principals on Student Achievement on Public School Campuses in Texas

The purpose of this descriptive study was to determine if business leadership practices by Texas public school principals have an impact on principals' campus student achievement in mathematics and reading, as measured by TAKS scores. The survey instrument was the Leadership Assessment Instrument (LAI), developed by Warren Bennis in 1989. The survey instrument was electronically distributed to a sample of 300 public school principals in Texas. Of the 300, 140 principals completed and returned the survey, for a response rate of 47%. The Statistical Package for the Social Sciences (SPSS), version 16.0, was used for the analysis of data, which included descriptive statistics, analysis of variance, and regression. In addition, reliability for the LAI was also calculated. The LAI consists of the following five categories of effective business practices: focused drive, emotional intelligence, building trust, conceptual thinking, and systems thinking. No significant relationships were found between principals' use of LAI elements and student achievement in mathematics and reading. However, the lack of significant relationships between the business model as used in public schools and student achievement reveals that current models of principal preparation programs do not result in school leaders who are adequately prepared to increase student achievement. Further research …
Date: December 2009
Creator: Cooper, Kary M.
System: The UNT Digital Library
Hypoxic and hyperoxic incubation affects the ductus arteriosus in the developing chicken embryo (Gallus gallus). (open access)

Hypoxic and hyperoxic incubation affects the ductus arteriosus in the developing chicken embryo (Gallus gallus).

Developing chicken embryos have two ductus arteriosus (DA) that shunt blood away from the lungs and to the chorioallantoic membrane, the embryonic gas exchanger. In mammals, DA closure is stimulated by an increase in blood gas O2 that occurs as the animal begins to breathe with its lungs. The goal of this study was to determine the influence of O2 levels during incubation on the vascular reactivity and morphology of the O2-sensitive DA and to examine the effects of changing O2 levels during late incubation on the morphology of the DA from chicken embryos. In comparison to normoxia, hypoxia (15%) reduced venous O2 levels in day 16 and day 18 embryos and reduced aircell O2 values in day 16, day 18, and internally pipped (IP) embryos, whereas hyperoxia (30%) increased venous O2 levels and aircell O2 level in day 16, day 18, and IP embryos. In comparison to normoxia, hypoxia delayed closure of the DA, whereas hyperoxia accelerated DA closure. In comparison to the left DA from externally pipped (EP) normoxic embryos, the left DA from EP hypoxic embryos exhibited a significantly weaker contractile response to O2. The DA from day 18 hypoxic embryos exhibited a significantly weaker contractile response …
Date: December 2009
Creator: Copeland, Jennifer
System: The UNT Digital Library