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 Degree Level: Doctoral
 Collection: UNT Theses and Dissertations
4-Ethoxymethylphenol: a novel phytoestrogen that acts as an agonist for human estrogen receptors.

4-Ethoxymethylphenol: a novel phytoestrogen that acts as an agonist for human estrogen receptors.

Access: Use of this item is restricted to the UNT Community.
Date: December 2001
Creator: Pearce, Virginia
Description: Estrogen is the natural agonist of the estrogen receptor (ER). However, certain plant-derived compounds or phytoestrogens have been identified that mimic estrogens and act as agonists and/or antagonists of ERs, depending on subtype and target tissue. Understanding how phytoestrogens interact with ERs, and therefore effect the estrogenic response, may prove beneficial in hormone replacement therapy and in the prevention and treatment of hormone-related diseases. Using Thin Layer Chromatography, gas chromatography/mass spectrometry (GC/MS), and proton nuclear nagnetic resonance (HNMR), I identified 4-ethoxymethylphenol (4EM) found in Maclura pomifera. While most phytoestrogens are heterocyclic compounds, 4EM is a simple phenol that acts as an agonist of ER-alpha and -beta in HeLa and MCF-7 cells. To study the effect of 4EM on ER-alpha and -beta activity, I performed transient transfection assays and showed that 4EM activates ER dependent gene transcription in a dose dependent manner in both ER subtypes. Further, 4EM- mediated transcription in ER-alpha, like estrogen, was enhance in the presense of co-activators, SRC-1 (steroid receptor coactivator-1), CBP (CREB binding proteins), and E6-AP (E6-associated protein) and inhibited by trans-4- hydroxytamoxifen (4HT). I found that 4EM was specific for ER and did not activate transcription of the progesterone receptor in HeLa cells.
Contributing Partner: UNT Libraries
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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The 1986 National Endowment for the Arts Commission: An introspective analysis of two marimba works, Reflections on the Nature of Water by Jacob Druckman and Velocities by Joseph Schwantner, together with three recitals of selected works by Keiko Abe, Christopher Deane, Peter Klatzow, Wayne Siegel, Gitta Steiner and others.

The 1986 National Endowment for the Arts Commission: An introspective analysis of two marimba works, Reflections on the Nature of Water by Jacob Druckman and Velocities by Joseph Schwantner, together with three recitals of selected works by Keiko Abe, Christopher Deane, Peter Klatzow, Wayne Siegel, Gitta Steiner and others.

Date: August 2005
Creator: Fang, I-Jen
Description: The marimba is rapidly achieving greater importance as a solo percussion instrument. Solo compositions for the marimba have been commissioned and performed only in the last sixty years. The 1986 National Endowment for the Arts Solo Marimba Commission is considered one of the most important commissioning projects in the history of marimba literature. Two compositions created through this project, Velocities by Joseph Schwantner and Reflections on the Nature of Water by Jacob Druckman have become two of the most influential works in contemporary marimba music. This thesis will focus on a historical perspective of the project, as well as theoretical aspects and performance issues related to these two compositions. The National Endowment for the Arts (NEA) issued a consortium commissioning grant through the Percussive Arts Society (PAS) in 1986 to three internationally renowned marimbists, William Moersch, Leigh Howard Stevens and Gordon Stout. Three Pulitzer Prize winners were brought together to compose three new works for the marimba. The resulting pieces were: Reflections on the Nature of Water by Jacob Druckman, Velocities by Joseph Schwantner, and Islands from Archipelago: Autumn Island by Roger Reynolds. A brief history of the classical concert marimba and the development of solo marimba literature is provided ...
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3D Reconstruction Using Lidar and Visual Images

3D Reconstruction Using Lidar and Visual Images

Date: December 2012
Creator: Duraisamy, Prakash
Description: In this research, multi-perspective image registration using LiDAR and visual images was considered. 2D-3D image registration is a difficult task because it requires the extraction of different semantic features from each modality. This problem is solved in three parts. The first step involves detection and extraction of common features from each of the data sets. The second step consists of associating the common features between two different modalities. Traditional methods use lines or orthogonal corners as common features. The third step consists of building the projection matrix. Many existing methods use global positing system (GPS) or inertial navigation system (INS) for an initial estimate of the camera pose. However, the approach discussed herein does not use GPS, INS, or any such devices for initial estimate; hence the model can be used in places like the lunar surface or Mars where GPS or INS are not available. A variation of the method is also described, which does not require strong features from both images but rather uses intensity gradients in the image. This can be useful when one image does not have strong features (such as lines) or there are too many extraneous features.
Contributing Partner: UNT Libraries
Ability Estimation Under Different Item Parameterization and Scoring Models

Ability Estimation Under Different Item Parameterization and Scoring Models

Date: May 2002
Creator: Si, Ching-Fung B.
Description: A Monte Carlo simulation study investigated the effect of scoring format, item parameterization, threshold configuration, and prior ability distribution on the accuracy of ability estimation given various IRT models. Item response data on 30 items from 1,000 examinees was simulated using known item parameters and ability estimates. The item response data sets were submitted to seven dichotomous or polytomous IRT models with different item parameterization to estimate examinee ability. The accuracy of the ability estimation for a given IRT model was assessed by the recovery rate and the root mean square errors. The results indicated that polytomous models produced more accurate ability estimates than the dichotomous models, under all combinations of research conditions, as indicated by higher recovery rates and lower root mean square errors. For the item parameterization models, the one-parameter model out-performed the two-parameter and three-parameter models under all research conditions. Among the polytomous models, the partial credit model had more accurate ability estimation than the other three polytomous models. The nominal categories model performed better than the general partial credit model and the multiple-choice model with the multiple-choice model the least accurate. The results further indicated that certain prior ability distributions had an effect on the accuracy ...
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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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Academic Achievement and Intelligence among Negro Eighth Grade Students as a Function of the Self Concept

Academic Achievement and Intelligence among Negro Eighth Grade Students as a Function of the Self Concept

Date: January 1966
Creator: Gay, Cleveland Johnson, 1912-
Description: The problem of the present study was to determine the self concept of selected Negro boys and girls and to study the relationships of their self concept to their intelligence and academic achievement.
Contributing Partner: UNT Libraries
The Academic Dean and His Role in the Improvement of Instruction

The Academic Dean and His Role in the Improvement of Instruction

Date: January 1960
Creator: Eskew, Cletis Theodore
Description: The purpose of this study was to determine changes in practices and beliefs which would be needed by certain academic deans to provide a sound program for the improvement of college instruction.
Contributing Partner: UNT Libraries
Academic Dishonesty:  Attitudes and Behaviors of Fundamentalist Christian College Students

Academic Dishonesty: Attitudes and Behaviors of Fundamentalist Christian College Students

Access: Use of this item is restricted to the UNT Community.
Date: December 2000
Creator: Sunday, William G.
Description: This study was designed to examine: (1) the extent to which cheating occurs in fundamentalist Christian colleges; (2) the attitudes of fundamentalist Christian college students toward cheating; (3) attitudes of fundamentalist Christian college students toward cheating among their peers; (4) the kinds of cheating practices of fundamentalist Christian college students; (5) the degree to which students engage in neutralizing behavior to justify cheating; (6) differences in cheating behaviors according to gender; (7) differences in cheating behaviors according to ethnicity; and (8) differences in cheating behaviors according to the length of duration of Christian commitment. Based upon the responses of 337 students attending 3 different Christian colleges, it was concluded that: (1) most Christian fundamentalist students do not engage in cheating; (2) respondents believe that each of 17 self-reported cheating behaviors are serious forms of cheating; (3) respondents are unlikely to report cheating among peers; (4) plagiarism is the most common cheating behavior; (5) most respondents justify cheating on the basis of the workload at school and the pressure to obtain good grades; (6) there are no differences in cheating behavior according to gender; (7) there are differences in cheating behavior according to groups; and (8) most respondents do not cheat ...
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Academic excellence and instructional expenditures in Texas.

Academic excellence and instructional expenditures in Texas.

Date: August 2006
Creator: Helvey, Jearl Kenton
Description: Public school per pupil costs and demands for better performance have increased over the past several decades. While the overall per pupil expenditures have increased, the percent of the educational dollar directed toward instructional activities has remained at approximately 60%. A grass-roots movement known as the "65% Solution" caught national attention by claiming that schools are not efficiently allocating resources into areas that have the greatest link to student achievement, such as instruction. Proponents of the 65% Solution claim that per pupil expenditures can be increased by shifting funds from areas considered non-instructional to areas that directly impact student instruction, such as teachers and instructional materials. The purpose of this study was to determine the relationship between district Panel Recommended and Commended Performance TAKS Reading/ELA and Math results and three measurements of instructional expenditures, Instructional Staff Percent; TEA Instructional Expenditure Ratio; and the NCES Instructional Expenditure Ratio (65% Solution), in Texas public schools. Data was collected from the 2003-2004 AEIS report. Multiple regression was used to conduct the analyses. In most instances, there was little, if any, relationship between TAKS Reading/ELA and TAKS Math, and the Instructional Staff Percent (ISP), TEA Instructional Expenditure Ratio (TIER), and NCES Instructional Expenditure Ratio ...
Contributing Partner: UNT Libraries
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