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 Decade: 2010-2019
 Degree Level: Doctoral
 Collection: UNT Theses and Dissertations
9-Lipoxygenase Oxylipin Pathway in Plant Response to Biotic Stress

9-Lipoxygenase Oxylipin Pathway in Plant Response to Biotic Stress

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Date: May 2012
Creator: Nalam, Vamsi J.
Description: The activity of plant 9-lipoxygenases (LOXs) influences the outcome of Arabidopsis thaliana interaction with pathogen and insects. Evidence provided here indicates that in Arabidopsis, 9-LOXs facilitate infestation by Myzus persicae, commonly known as the green peach aphid (GPA), a sap-sucking insect, and infection by the fungal pathogen Fusarium graminearum. in comparison to the wild-type plant, lox5 mutants, which are deficient in a 9-lipoxygenase, GPA population was smaller and the insect spent less time feeding from sieve elements and xylem, thus resulting in reduced water content and fecundity of GPA. LOX5 expression is induced rapidly in roots of GPA-infested plants. This increase in LOX5 expression is paralleled by an increase in LOX5-synthesized oxylipins in the root and petiole exudates of GPA-infested plants. Micrografting experiments demonstrated that GPA population size was smaller on plants in which the roots were of the lox5 mutant genotype. Exogenous treatment of lox5 mutant roots with 9-hydroxyoctadecanoic acid restored water content and population size of GPA on lox5 mutants. Together, these results suggest that LOX5 genotype in roots is critical for facilitating insect infestation of Arabidopsis. in Arabidopsis, 9-LOX function is also required for facilitating infection by F. graminearum, which is a leading cause of Fusarium head ...
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Absorptive Capacity:  An Empirical Examination of the Phenomenon and Relationships with Firm Capabilities

Absorptive Capacity: An Empirical Examination of the Phenomenon and Relationships with Firm Capabilities

Date: May 2012
Creator: Daspit, Josh
Description: The field of strategic management addresses challenges that firms encounter in an attempt to remain competitive. The ability to explain variation in firm success through examination of knowledge flows has become a prominent focus of research in the strategic management literature. Specifically, researchers have sought to further examine how firms convert knowledge, a phenomenon conceptualized as absorptive capacity. Absorptive capacity is the firm’s ability to acquire, assimilate, transform, and exploit knowledge. Few studies have captured the richness and multi-dimensionality of absorptive capacity, and it remains to be understood how the dimensions of the phenomenon convert knowledge. Furthermore, how absorptive capacity influences the firm remains to be understood. To address these research gaps, this dissertation seeks to (1) determine how absorptive capacity converts knowledge, and (2) determine how absorptive capacity influences firm capabilities. The research questions are investigated using structural modeling techniques to analyze data collected from software-industry firms. The findings offer contributions to the absorptive capacity and capability literatures. For example, absorptive capacity is hypothesized to consist of complex relationships among its internal dimensions. However, findings of this study suggest the relationships among the dimensions are linear in nature. This finding is in line with the theoretical foundations of and ...
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Accuracy and Efficiency in Computational Chemistry: The Correlation Consistent Composite Approach

Accuracy and Efficiency in Computational Chemistry: The Correlation Consistent Composite Approach

Date: August 2011
Creator: Wilson, Brent R.
Description: One of the central concerns of computational chemistry is that of efficiency (i.e. the development of methodologies which will yield increased accuracy of prediction without requiring additional computational resources – RAM, disk space, computing time). Though the equations of quantum mechanics are known, the solutions to these equations often require a great deal of computing power. This dissertation primarily concerns the theme of improved computational efficiency (i.e. the achievement of greater accuracy with reduced computational cost). Improvements in the efficiency of computational chemistry are explored first in terms of the correlation consistent composite approach (ccCA). The ccCA methodology was modified and this enhanced ccCA methodology was tested against the diverse G3/05 set of 454 energetic properties. As computational efficiency improves, molecules of increasing size may be studied and this dissertation explored the issues (differential correlation and size extensivity effects) associated with obtaining chemically accurate (within 1 kcal mol-1) enthalpies of formation for hydrocarbon molecules of escalating size. Two applied projects are also described; these projects concerned the theoretical prediction of a novel rare gas compound, FKrOH, and the mechanism of human glutathione synthetase’s (hGS) negative cooperativity. The final work examined the prospect for the parameterization of the modified embedded atom ...
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Actions Taken by Texas School Districts to Prevent Fraud

Actions Taken by Texas School Districts to Prevent Fraud

Date: May 2011
Creator: Taylor, Gordon Douglas
Description: This research is a descriptive analysis answering the question, what measures are currently taken by the leadership―boards of trustees and superintendents of schools―of Texas school districts to prevent embezzlement? The research perspective utilized was quantitative with a descriptive, cross-sectional design. Data collection was accomplished through a survey with questions constructed from the most commonly recommended strategies discovered through the review of literature. The survey was distributed to the 1031 superintendents of school districts in Texas via email. The response rate was 33% or 339 returned surveys. The data set created concentrates on the four most common preventive measures: policy and procedure, management, auditing, and ethics. These measures are considered as they function to interrupt the principles of the fraud triangle. Comparisons were completed regarding region, district size, superintendent tenure and superintendent experience. Policy adoption was found to be extremely widespread. Procedures written to fully implement policy were less prevalent. Review of management practices found problems concerning credit cards, personnel evaluations, and password access to multiple computer finance recordkeeping systems concentrated in one employee. External auditing programs were universal due to statutory mandate but internal auditors and internal audit committees were few. Ethics training for business office personnel existed but with ...
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Adlerian Play Therapy: Effectiveness on Disruptive Behaviors of Early Elementary-Aged Children

Adlerian Play Therapy: Effectiveness on Disruptive Behaviors of Early Elementary-Aged Children

Date: August 2010
Creator: Meany-Walen, Kristin K.
Description: Approximately 20% of children experience serious mental health problems severe enough to meet diagnosis criteria, and less than one third of these children receive the services they need. Identifying effective school-based counseling interventions provides a viable and accessible solution, especially for families with financial barriers. This randomized, controlled outcome study examined the effectiveness of Adlerian play therapy (AdPT) compared to reading mentoring (RM) with 58 kindergarten through third grade students who qualified with clinical levels of disruptive behavior in the classroom. Participants were identified as 48% Latino, 33% European American, and 19% African American. Approximately four-fifths of participants were male. Children were randomly assigned to AdPT (experimental group) or RM (active control group) for 16 sessions of treatment. Children in both groups participated in twice weekly, individual, 30-minute interventions that took place in their schools. Results from a two (group) by two (repeated measures) split plot ANOVA indicated that, compared to the RM group over time, the AdPT group demonstrated statistically significant improvement on (a) disruptive behaviors in the classroom, as directly observed by objective raters and as reported by teachers, and (b) stress in the teacher-child relationship, as reported by teachers. Teachers and observers were blinded to children's treatment ...
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Adult Attachment Patterns, Mental Representation of Self, and Faith: Mediators of Childhood Trauma and Affect-Behavior Regulations in Adulthood

Adult Attachment Patterns, Mental Representation of Self, and Faith: Mediators of Childhood Trauma and Affect-Behavior Regulations in Adulthood

Date: December 2010
Creator: Han, GiBaeg
Description: The purpose of this study was to investigate psychological mechanism by which four intra- and inter-personal characteristics of an individual (anxious and avoidant adult attachment patterns, images of self, and religious faith) mediate the relationship between childhood trauma and each of three affect-behavior regulation problems in adulthood (symptoms of depression, disordered eating behaviors, and substance abuse). A total of 401 college student participants completed a packet of 18 surveys including 10 surveys used in the present study. Structural equation modeling was used to test each of three hypothesized structural models (Depression, Eating Disturbances, and Substance Abuse). A series of multi-group analyses conducted to test if each of three hypothesized models is invariant across gender indicated no significant difference between females and males. Thus, the data were combined across gender to test for mediated effects in each of three hypothesized models. The results indicated: (a) for the hypothesized model for depression, anxious attachment patterns, avoidant attachment patterns, and negative self-images, but not religious faith, fully mediated the relationship between childhood trauma and symptoms of depression; (b) for the model for eating disturbances, anxious attachment and negative images of self, but not avoidant attachment and religious faith, fully mediated the association between ...
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Advancements in Instrumentation for Fourier Transform Microwave Spectroscopy

Advancements in Instrumentation for Fourier Transform Microwave Spectroscopy

Date: August 2011
Creator: Dewberry, Christopher Thomas
Description: The efforts of my research have led to the successful construction of several instruments that have helped expand the field of microwave spectroscopy. The classic Balle-Flygare spectrometer has been modified to include two different sets of antenna to operate in the frequency ranges 6-18 GHz and 18-26 GHz, allowing it to function for a large range without having to break vacuum. This modified FTMW instrument houses two low noise amplifiers in the vacuum chamber to allow for the LNAs to be as close to the antenna as physically possible, improving sensitivity. A new innovative Balle-Flygare type spectrometer, the efficient low frequency FTMW, was conceived and built to operate at frequencies as low as 500 MHz through the use of highly curved mirrors. This is new for FTMW techniques that normally operate at 4 GHz or higher with only a few exceptions around 2 GHz. The chirped pulse FTMW spectrometer uses horn antennas to observe spectra that span 2 GHz versus the standard 1 MHz of a cavity technique. This instrument decreases the amount of time to obtain a large spectral region of relative correct intensity molecular transitions. A Nd:YAG laser ablation apparatus was attached to the classic Balle-Flygare and chirped ...
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Aerospace and Defense Industries Online Recruiting of College and University Graduates: Strategies Toward Defining a Comprehensive Informational Benchmark

Aerospace and Defense Industries Online Recruiting of College and University Graduates: Strategies Toward Defining a Comprehensive Informational Benchmark

Date: August 2011
Creator: Holland, Marcia Annette
Description: This qualitative, inductive study analyzed online recruiting information posted at the websites of five major aerospace and defense corporations to recruit college juniors, seniors, and recent graduates. Recruitment of this group is critical to staff the personnel for the scientific, technical, and management needs of aerospace and defense industries. The study sought: (1) to determine the use of multiple recruitment factors inferred from the literature and recommended for successful recruitment of college graduates, (2) to determine use of online social media (Facebook, Twitter, LinkedIn) to recruit this population, and (3) to explore commonalities among these corporations regarding online recruiting information to determine if a model for online recruitment now exists. A matrix of recruitment factors was developed from a review of the literature on the personnel needs of this industry and on effective recruiting factors for this group. Content analysis involved filtering information at each website with the matrix. Conclusions of this study include: (1) the matrix of recruitment factors and the rating scale developed for the purposes of this study provide a tool for researching, documenting, and comparing recruitment information on the internet; (2) that while these corporations represent the latest applications in technology in their manufacturing processes and ...
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Aesthetic and Technical Analysis on Soar!

Aesthetic and Technical Analysis on Soar!

Date: August 2010
Creator: Wang, Hsiao-Lan
Description: Soar! is a musical composition written for wind ensemble and computer music. The total duration of the work is approximately 10 minutes. Flocking behavior of migratory birds serves as the most prominent influence on the imagery and local structure of the composition. The cyclical nature of the birds' journey inspires palindromic designs in the temporal domain. Aesthetically, Soar! portrays the fluid shapes of the flocks with numerous grains in the sounds. This effect is achieved by giving individual parts high degree of independence, especially in regards to rhythm. Technically, Soar! explores various interactions among instrumental lines in a wind ensemble, constructs overarching symmetrical structures, and integrates a large ensemble with computer music. The conductor acts as the leader at several improvisational moments in Soar! The use of conductor-initiated musical events in the piece can be traced back through the historic lineage of aleatoric compositions since the middle of the twentieth century. [Score is on p. 54-92.]
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The Affect of Mobile Performance Support Devices on Anxiety and Self-Efficacy of Hospital Float Staff

The Affect of Mobile Performance Support Devices on Anxiety and Self-Efficacy of Hospital Float Staff

Date: May 2012
Creator: McKee, Megan Riley
Description: Floating describes the act of staff moving from one unit to another based on the needs of the patients in a hospital. Many staff who float to different units express negative feelings, including anxiety and lack in self-efficacy. However, floating is both an economical and efficient method to use staff across the hospital, especially with current staffing shortages in the United States. This study investigated how the use of mobile performance support devices may help reduce anxiety and increase self-efficacy for those staff who float to different units. with access to multiple resources available on the mobile device, Bandura's social learning theory and self-efficacy concept set the framework through modeling, observing, and imitating others in order to reproduce certain behaviors and tasks and believe in one's capability to perform. a quantitative study incorporating the retrospective pretest-posttest design was conducted using the population of float staff, including both nurses and respiratory therapists, from Children's Medical Center of Dallas. Both the State-Trait Anxiety Inventory and General Self-Efficacy Scale, along with a basic demographic tool, were used to explore anxiety and self-efficacy in relation to the usage of mobile performance support devices. Findings can be used to impact the negative feelings of staff ...
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