Degree Level

Comparative Morphology of Sensilla Styloconica on the Proboscis of North American Nymphalidae and Other Selected Taxa: Systematic and Ecological Considerations.

Access: Use of this item is restricted to the UNT Community
Sensilla styloconica on the proboscis of 107 species of North American and tropical butterflies were comparatively studied using the scanning electron microscope. Focus was on 76 species of North American Nymphalidae representing 45 genera and 11 subfamilies. Nomenclature for generalized and specific types of nymphalid sensilla is proposed. Written descriptions and micrographs are presented for each species studied. Morphological features were generally consistent for all or most species within genera and sometimes within subfamilies, with specified exceptions. Statistical analysis revealed significant differences for six of eight variables tested between two distinct feeding guilds of North American Nymphalidae. Average number, density, extent of proboscis coverage with sensilla, their total length, and shoulder spine length were all significantly greater in the non-nectar feeding guild than in nectar feeders, and may indicate adaptation for greater efficiency in feeding on flat surfaces. The greater frequency of apical shoulder spines in non-nectar feeders may represent adaptation for protection of sensory pegs from mechanical abrasion during feeding, or for anchoring the flexible proboscis tip to the surface. Correlation analysis revealed 9 out of 28 positive correlations in nectar feeders and 5 out of 28 in non-nectar feeders. Results of preliminary cladistic analysis were not considered to …
Date: December 2001
Creator: Petr, Daniel
System: The UNT Digital Library

The Effects of Web-Based Learning Versus Traditional Instructor-Based Learning on Student Knowledge and Satisfaction Based on Student Learning Styles

Access: Use of this item is restricted to the UNT Community
The purpose of this study was to compare the effects of Web-based learning (WBL) versus those of traditional instructor-based learning (IBL) on student knowledge and satisfaction based on student learning styles. Other goals were to determine if WBL is more effective for those with a particular learning style. The study examined a sample of undergraduate students who were enrolled in the college algebra offered as both oncampus instructor-based (traditional) and Web-based at the university of North Texas (UNT). A total of 36 Web-based students and 58 instructor-based students participated in this study. This study utilized a posttest-only intact group. The Kolb Learning Style Inventory (LSI) measured the learning styles of students. This study used learning methods (Web-based learning (WBL), instructor-based learning (IBL)), and learning styles (Diverger, Converger, Assimilator, and Accommodator) as independent variables. Student knowledge and student satisfaction was measured at the end of the course as independent variables. Based upon the results of the LSI, post-learning exam, and satisfaction a series of two-way analysis of variance (ANOVA 4x2) techniques and independent variable tests was used for each of the dependent variables, knowledge and satisfaction, based on a student's learning styles. The results revealed that students' learning styles were statistically …
Date: December 2001
Creator: Manochehri, Naser
System: The UNT Digital Library

Electroencephalographic (EEG) biofeedback treatment for children with attention deficit disorders in a school setting.

Access: Use of this item is restricted to the UNT Community
The purpose of this study was to explore the use of EEG biofeedback in a school setting to assist students who had attentional challenges. The equipment for implementing biofeedback was relatively inexpensive and was easily integrated into the school setting. Twenty students ranging in age from 7 to 17 were recruited for this study. Data was used from 14 subjects, 12 males (2 Hispanic, 1 African American, and 10 Caucasian) and 2 females (1 Hispanic, 1 Caucasian.) The subject pool was reduced due to non-compliance or the students. moving from the school district. Significant effect size was obtained in the treatment group in areas pertaining to visual perception and motor coordination. However, significant effect sizes in other areas were obtained when the control group scores worsened. The inclusion of student subjects who, perhaps, did not meet stringent criterion of attention deficit may have skewed the results. The small number of students in the study may have hindered accurate measures of statistical significance. Conversely, the information obtained from this study may offer insight to school districts in providing their students an alternate/adjunct to psychopharmacological medication and a non- invasive method of helping students with psycho-social challenges.
Date: December 2001
Creator: Mosse, Leah Kathryn
System: The UNT Digital Library

Mechanisms of Methoxide Ion Substitution and Acid- Catalyzed Z/E Isomerization of N-Methoxyimines

Access: Use of this item is restricted to the UNT Community
The second order rate constants for nucleophilic substitution by methoxide of (Z)- and (E)-O-methylbenzohydroximoyl fluorides [C6H4C(F)=NOCH3] with various substituents on the phenyl ring [p-OCH3 (1h, 2h), p-CH3 (1g, 2g), p-Cl (1f, 2f), p-H (1e, 2e), (3,5)-bis-CF3 (1i, 2i)] in 90:10 DMSO:MeOH have been measured. A Hammett plot of these rate constants vs σ values gave positive ρ values of 2.95 (Z isomer) and 3.29 (E isomer). Comparison of these rates with methoxide substitution rates for Omethylbenzohydroximoyl bromide [C6H4C(Br)=NOCH3] and Omethylbenzohydroximoyl chloride [C6H4C(Cl)=NOCH3] reveal an element effect for the Z isomers of Br:Cl:F(1e) = 2.21:1.00:79.7 and for the E isomers of Cl:F(2e) = 1.00:18.3. With the p-OCH3-imidoyl halides the following element effects are found: Br:Cl:F(1h) = 2.78:1.00:73.1 for the Z isomer and Br:Cl:F(2h) = 1.97:1.00:12.1 for the E isomer. Measurement of activation parameters revealed ∆S≠ = -17 eu for 1e and ∆S≠ = -9.9 eu for 2e. Ab initio calculations (HF/6-31+G*, MP2/6-31+G*//HF/6-31+G*, B3LYP/6- 31+G*//HF/6-31+G*, HF-SCIPCM/6-31+G*//HF/6-31+G*) were performed to define the reaction surface. These calculations demonstrate a relatively large barrier for nucleophilic attack in relation to halogen loss and support the experimental findings that this reaction proceeds by an addition-elimination mechanism (AN# + DN). The imidoyl fluorides have been used to synthesize …
Date: December 2001
Creator: Dolliver, Debra D.
System: The UNT Digital Library

A meta-analysis of service learning research in middle and high schools.

Access: Use of this item is restricted to the UNT Community
This study examines the relationship between service learning innovations and improved academics, self-concept, and social or personal growth in middle and high school students. Meta-Analysis is employed to arrive at effect-size estimates for each construct. A historical overview of service learning is presented and a detailed description of the study selection process is provided. The data revealed a moderate relationship between service learning participation and academics, self-concept and social or personal growth in middle and high school students. The findings are presented, and some appropriate conclusions are drawn. A discussion of the implications of these findings and recommendations for future research are also provided.
Date: December 2001
Creator: White, Amy E.
System: The UNT Digital Library

Music preferences, music and non-music media use, and leisure involvement of Hong Kong adolescents.

Access: Use of this item is restricted to the UNT Community
The study sought to determine the relationships of preference responses to grade, gender, familiarity, musical training, peers'/parents' listening habits, music media use, and listening contexts. Grade six through nine Hong Kong students (N = 310) completed the audio preference test followed by verbal responses to training, peers'/parents' preferences, leisure/music media involvement, and listening context. Results indicated: The preferred genres, in descending order, were Western pop/rock, Cantopop/rock, Western classical; the disliked genres were jazz, Chinese, and non- Western/non-Chinese. Preference correlated strongly with genre familiarity. Pop genres were the most familiar to all adolescents. The students' preference toward Western pop/rock and Cantopop/rock associated with several listening contexts: solitary listening, having great freedom to choose one's desired music for listening, listening to music in one's room, and listening to music as background activity. The adolescents expressed that their leisure activities were spent with their family and friends. However, they made it clear that music listening was a personal activity that very likely was listened to alone. On all listening occasions, the girls exhibited a more positive response than the boys did. With four to five hours daily leisure time, the adolescents watched TV for three to four hours while spending less than two …
Date: December 2001
Creator: Hui, Viny Wan-Fong
System: The UNT Digital Library

A Novel Phytoestrogen that Acts as an Agonist for Human Estrogen Receptors.

Access: Use of this item is restricted to the UNT Community
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.
Date: December 2001
Creator: Pearce, Virginia
System: The UNT Digital Library

Quantization Dimension for Probability Definitions

Access: Use of this item is restricted to the UNT Community
The term quantization refers to the process of estimating a given probability by a discrete probability supported on a finite set. The quantization dimension Dr of a probability is related to the asymptotic rate at which the expected distance (raised to the rth power) to the support of the quantized version of the probability goes to zero as the size of the support is allowed to go to infinity. This assumes that the quantized versions are in some sense ``optimal'' in that the expected distances have been minimized. In this dissertation we give a short history of quantization as well as some basic facts. We develop a generalized framework for the quantization dimension which extends the current theory to include a wider range of probability measures. This framework uses the theory of thermodynamic formalism and the multifractal spectrum. It is shown that at least in certain cases the quantization dimension function D(r)=Dr is a transform of the temperature function b(q), which is already known to be the Legendre transform of the multifractal spectrum f(a). Hence, these ideas are all closely related and it would be expected that progress in one area could lead to new results in another. It would …
Date: December 2001
Creator: Lindsay, Larry J.
System: The UNT Digital Library

Richard Thompson Archer and the Burdens of Proprietorship: The Life of a Natchez District Planter

Access: Use of this item is restricted to the UNT Community
In 1824 a young Virginia aristocrat named Richard Thompson Archer migrated to Mississippi. Joining in the boom years of expansion in the Magnolia State in the 1830s, Archer built a vast cotton empire. He and his wife, Ann Barnes, raised a large family at Anchuca, their home plantation in Claiborne County, Mississippi. From there Richard Archer ruled a domain that included more than 500 slaves and 13,000 acres of land. On the eve of the Civil War he was one of the wealthiest men in the South. This work examines the life of Richard Archer from his origins in Amelia County, Virginia, to his death in Mississippi in 1867. It takes as its thesis the theme of Archer's life: his burdens as proprietor of a vast cotton empire and as father figure and provider for a large extended family. This theme weaves together the strands of Archer's life, including his rise to the position of great planter, his duties as husband and father, and his political beliefs and activities. Archer's story is told against the background of the history of Mississippi and of the South, from their antebellum heyday, through the Civil War, and into the early years of Reconstruction. …
Date: December 2001
Creator: Hammond, Carol D.
System: The UNT Digital Library

Selected Songs for Chamber Winds and Soprano: Rediscovering a Forgotten Repertoire of John Philip Sousa

Access: Use of this item is restricted to the UNT Community
For over one hundred years, the music-going public has reflected on the life and influence of America's “March King,” John Philip Sousa. His popularity as a bandleader was unprecedented, and his reputation as an entertainer captivated the imagination and intrigue of a nation. Sousa's fame was attained through the high standards showcased by his unparalleled concert organization, the Sousa Band. He is interminably linked to the march, and for his seventy-seven years he proved to be its prolific and outspoken champion. Sousa's songs, however, were among his favorite works, and their presence on concert programs reinforced a variety of programming that was the hallmark of his success. The Sousa Band served as a cultural and musical ambassador, and annual transcontinental tours brought music to people where they lived. Sousa's songs were highly anticipated concert features, and were presented by soprano soloists known as the “Ladies in White.” A chamber winds instrumentation, rather than employment of the full-forces of the Sousa Band, allowed for an appropriate musical balance between instruments and voice. The “Forgotten Songs of John Philip Sousa Project” involved the research, editing, and performance of songs housed in the Sousa Archives for Band Research at the University of Illinois. …
Date: December 2001
Creator: Hemberger, Glen J.
System: The UNT Digital Library

The Stopping of Energetic Si, P and S Ions in Ni, Cu, Ge and GaAs Targets

Access: Use of this item is restricted to the UNT Community
Accurate knowledge of stopping powers is essential for these for quantitative analysis and surface characterization of thin films using ion beam analysis (IBA). These values are also of interest in radiobiology and radiotherapy, and in ion- implantation technology where shrinking feature sizes puts high demands on the accuracy of range calculations. A theory that predicts stopping powers and ranges for all projectile-target combinations is needed. The most important database used to report the stopping powers is the SRIM/TRIM program developed by Ziegler and coworkers. However, other researchers report that at times, these values differ significantly from experimental values. In this study the stopping powers of Si, P and S ions have been measured in Ni, Cu, Ge and GaAs absorbers in the energy range ~ 2-10 MeV. For elemental films of Ni, Cu and Ge, the stopping of heavy ions was measured using a novel ERD (Elastic Recoil Detection) based technique. In which an elastically recoiled lighter atom is used to indirectly measure the energy of the incoming heavy ion using a surface barrier detector. In this way it was possible to reduce the damage and to improve the FWHM of the detector. The results were compared to SRIM-2000 predictions …
Date: December 2001
Creator: Nigam, Mohit
System: The UNT Digital Library

Teacher Practice, Curriculum, and Children's Moral Development in Buddhist Temple Preschools in Thailand

Access: Use of this item is restricted to the UNT Community
This study investigated what constitutes a moral development program in Buddhist temple preschools in Thailand. The researcher employed three qualitative methods: structured, in-depth interviews, observations of teachers' instruction, and document analysis of curriculum guides. Four Buddhist temple preschools were selected as the sites. Participants for interview included three abbots and one head nun, four principals, and twelve teachers. Participants for observations included four teachers of third year classes in each preschool. The study concentrated on four research questions: (a) what are the elements of the character education curriculum? (b) How do teachers teach moral development concepts and skills? (c) What are the teachers' perceptions of the moral development of third year preschoolers? (d) How do teachers assess their pupils' moral development? Key findings for the research questions were: character education was not a subject in the National Preschool Curriculum which was implemented in the Buddhist temple preschools. Core morality was integrated into every topic. The moral behaviors emphasized in the curriculum and the lesson plans included discipline, mindfulness, kindness, helpfulness, patience, honesty, respect, thriftiness, and politeness. The Buddhist concept of the process of moral development includes character education and meditation. The preschoolers were trained to pay respect to teachers and …
Date: December 2001
Creator: Phisalaphong, Rathdow
System: The UNT Digital Library

Topological uniqueness results for the special linear and other classical Lie Algebras.

Access: Use of this item is restricted to the UNT Community
Suppose L is a complete separable metric topological group (ring, field, etc.). L is topologically unique if the Polish topology on L is uniquely determined by its underlying algebraic structure. More specifically, L is topologically unique if an algebraic isomorphism of L with any other complete separable metric topological group (ring, field, etc.) induces a topological isomorphism. A local field is a locally compact topological field with non-discrete topology. The only local fields (up to isomorphism) are the real, complex, and p-adic numbers, finite extensions of the p-adic numbers, and fields of formal power series over finite fields. We establish the topological uniqueness of the special linear Lie algebras over local fields other than the complex numbers (for which this result is not true) in the context of complete separable metric Lie rings. Along the way the topological uniqueness of all local fields other than the field of complex numbers is established, which is derived as a corollary to more general principles which can be applied to a larger class of topological fields. Lastly, also in the context of complete separable metric Lie rings, the topological uniqueness of the special linear Lie algebra over the real division algebra of quaternions, …
Date: December 2001
Creator: Rees, Michael K.
System: The UNT Digital Library

Alexander Johnson's Ni' Concerto (1994) - Concerto no. 1 for Piano and Orchestra: a Discussion of Influences from Africa, Eastern and Western Europe

Access: Use of this item is restricted to the UNT Community
In the new generation of artists emerging in South Africa, Alexander Johnson is considered the most prolific young composer of his day. In a recent review in the Pretoria News, Johnson has been praised by eminent critic Paul Boekkooi as a composer who has “an ear for the exotic and knows exactly how to bring it off....” He continued by noting that his music is “mentally engrossing, pleasurable to the senses and seems refreshingly free from dogmatic formulas." Johnson writes for musicians and the general public to equal satisfaction. His accessible compositions and catching use of melodic materials have made his writings very popular both in South Africa and abroad. During his residency in Belgrade in 1993-94, Johnson met Croatian pianist Dorian Leljak. Impressed with Johnson's compositional ideas and output, Leljak commissioned a work from Johnson for piano and orchestra. The result was the Niš Concerto, which Johnson completed in April 1994. The world premiere took place on June 23, 1994 with the Niš Philharmonic Orchestra conducted by Anatoli Nowiestski with Dorian Leljak as soloist. The Niš Concerto received its South African premiere in 1995 during a simultaneous celebration for “Europe Day” and the new democracy of the Republic of …
Date: August 2001
Creator: Malan, Petronel
System: The UNT Digital Library

Anne Brontë's New Women: Agnes Grey and The Tenant of Wildfell Hall as Precursors of New Woman Fiction

Access: Use of this item is restricted to the UNT Community
Anne Brontë's Agnes Grey and The Tenant of Wildfell Hall were published more than forty years before the appearance of the feminist type that the Victorians called the “New Woman;” yet, both novels contain characteristics of New Woman fiction. By considering how Brontë's novels foreshadow New Woman fiction, the reader of these novels can re-enact the “gentlest” Brontë as an influential feminist whose ideology informed the construction of the radical New Woman. Brontë, like the New Woman writers, incorporated autobiographical dilemmas into her fiction. By using her own experiences as a governess, Brontë constructs Agnes Grey's incongruent social status and a morally corrupt gentry and aristocracy through her depiction of not only Agnes's second employers, the Murrays, but also the morally debauched world that Helen enters upon her marriage to Arthur Huntingdon in The Tenant of Wildfell Hall. Moreover, Brontë incorporates her observations of Branwell's alcoholism and her own religious beliefs into The Tenant of Wildfell Hall. Although Brontë's novels contain autobiographical material, her heroines are fictional constructions that she uses to engage her readers with the woman question. Brontë accomplishes this engagement through her heroines' narrative re-enactments of fictional autobiographical dilemmas. Helen's diary and Agnes's diary-based narrative produce the …
Date: August 2001
Creator: Phillips, Jennifer K.
System: The UNT Digital Library

Burnout Among Student Affairs Professionals at Metropolitan Universities

Access: Use of this item is restricted to the UNT Community
The purpose of this study was to determine the level of burnout among student affairs professionals at the 52 U.S. member institutions of the Coalition of Urban and Metropolitan Universities. Packets containing the Maslach Burnout Inventory (MBI), the Moos Work Environment Scale (WES), and a demographic survey were mailed to 371 senior student affairs administrators at the member institutions, with a completed response rate of 58.22%. The senior student affairs administrators surveyed included the chief student affairs officers and the professional staff who reported to them. The research design employed t-tests, analyses of variance, and Pearson's Product Moment correlations. The scores obtained from the MBI and WES subscales were compared overall and along 9 independent variablestitle of position, size of institution, appointment, salary, years in current position, years in profession, age, gender, and highest degree attained. Average levels of burnout were found on each of the MBI subscores. Contrary to earlier studies, women did not suffer from statistically significant higher levels of burnout than men, and burnout levels decreased with age and years in the profession for both sexes. Lower scores on the MBI depersonalization subscale were found in employees in mid-career and in professionals from smaller schools. Emotional exhaustion …
Date: August 2001
Creator: Murphy, Lynda
System: The UNT Digital Library

A Comparison of Five Robust Regression Methods with Ordinary Least Squares: Relative Efficiency, Bias and Test of the Null Hypothesis

Access: Use of this item is restricted to the UNT Community
A Monte Carlo simulation was used to generate data for a comparison of five robust regression estimation methods with ordinary least squares (OLS) under 36 different outlier data configurations. Two of the robust estimators, Least Absolute Value (LAV) estimation and MM estimation, are commercially available. Three authormodified variations on MM were also included (MM1, MM2, and MM3). Design parameters that were varied include sample size (n=60 and n=180), number of independent predictor variables (2, 3 and 6), outlier density (0%, 5% and 15%) and outlier location (2x,2y s, 8x8y s, 4x,8y s and 8x,4y s). Criteria on which the regression methods were measured are relative efficiency, bias and a test of the null hypothesis. Results indicated that MM2 was the best performing robust estimator on relative efficiency. The best performing estimator on bias was MM1. The best performing regression method on the test of the null hypothesis was MM2. Overall, the MM-type robust regression methods outperformed OLS and LAV on relative efficiency, bias, and the test of the null hypothesis.
Date: August 2001
Creator: Anderson, Cynthia, 1962-
System: The UNT Digital Library

The Developmental Physiology of the Zebrafish: Influence of Environment and Cardiovascular Attributes

Access: Use of this item is restricted to the UNT Community
Temperature effects on the development of the zebrafish embryos and larvae and adults were examined. It was found that the earlier in development a temperature change was performed on an embryo, the more significant the change in survival and/or subsequent development. Thus, viable temperature ranges for zebrafish widened significantly as development proceeded. Adults reared and bred at 25oC produced embryos that were significantly more successful at the lower range of rearing temperatures compared to embryos produced from adults reared at 28oC. The majority of this study focused on the physiological effects of swim training during development in the zebrafish. The earlier in development the zebrafish larvae were trained, the greater the mortality. Trained free swimming larvae had a significantly higher routine oxygen consumption after 11 days of training, and a higher mass specific routine metabolic rate after 8 and 11 days of training. Trained free swimming larvae consumed significantly less oxygen during swimming and were more efficient at locomotion, compared to control larvae. Training enhanced survival during exposure to extreme hypoxia in all age groups. Performance aspects of training were investigated in attempt to quantify training effects and in most cases, trained fish performed significantly better than controls. As blood …
Date: August 2001
Creator: Bagatto, Brian
System: The UNT Digital Library

East Meets West: Nationalistic Elements in Selected Piano Solo Works of Chen Yi

Access: Use of this item is restricted to the UNT Community
Since the founding of "New China" in 1949, the musical culture has undergone numerous periods of identity crisis, particularly during the ten-year "Cultural Revolution," due to the fact that music had always been used to serve the needs of political propaganda. Even the development of a "National Style" encouraged by the central government was a political "brainchild" under the socialist ideology. Nevertheless, professional musicians struggled to create a new path in musical composition while walking on the thin ice of harsh political climate. Isolated from the rest of the world for almost two decades, China's musical development had not been able to keep pace with the world until the late 1970s, when the central government reevaluated its agenda on how to lead the country. This change of political environment eventually led to a more open society. The newly established contact with the outside world in the musical scene lent great opportunities for Chinese musicians to study the newest thinking about music, which ultimately, in the early 1980s, fostered the emergence of a new "National Style"- the so-called "New Wave." The style of "New Wave" differs drastically from the earlier "National Style" in that it employs primarily twentieth-century compositional techniques in …
Date: August 2001
Creator: Li, Songwen
System: The UNT Digital Library

The Pettis Integral and Operator Theory

Access: Use of this item is restricted to the UNT Community
Let (Ω, Σ, µ) be a finite measure space and X, a Banach space with continuous dual X*. A scalarly measurable function f: Ω→X is Dunford integrable if for each x* X*, x*f L1(µ). Define the operator Tf. X* → L1(µ) by T(x*) = x*f. Then f is Pettis integrable if and only if this operator is weak*-to-weak continuous. This paper begins with an overview of this function. Work by Robert Huff and Gunnar Stefansson on the operator Tf motivates much of this paper. Conditions that make Tf weak*-to-weak continuous are generalized to weak*-to­weak continuous operators on dual spaces. For instance, if Tf is weakly compact and if there exists a separable subspace D X such that for each x* X*, x*f = x*fχDµ-a.e, then f is Pettis integrable. This nation is generalized to bounded operators T: X* → Y. To say that T is determined by D means that if x*| D = 0, then T (x*) = 0. Determining subspaces are used to help prove certain facts about operators on dual spaces. Attention is given to finding determining subspaces far a given T: X* → Y. The kernel of T and the adjoint T* of T are used …
Date: August 2001
Creator: Huettenmueller, Rhonda
System: The UNT Digital Library

The Relationship between Executive and Psychosocial Functioning in Children Treated for a Brain Tumor

Access: Use of this item is restricted to the UNT Community
This study examined the relationship between executive and psychosocial functioning in 45 children and adolescents age 6 to 17 years who had been treated for a brain tumor. Executive functioning deficits can profoundly impact an adult's ability to function successfully in life. The purpose of the study was to evaluate the potential impact of executive functioning deficits on the day-to-day functioning in a pediatric population. The domains of executive functioning assessed included cognitive flexibility, conceptual thinking, sustained attention, and response inhibition. Psychosocial functioning was assessed using both parent and child report. Several significant relationships were found for adolescents ages 15 and older, with effect sizes ranging from medium to large. In particular, cognitive flexibility and conceptual thinking were significantly related to parent report of depression and adaptive functioning. Fewer significant relationships with smaller effect sizes were found for younger children. The results may reflect the developmental emergence of executive functioning abilities and late effects of executive functioning deficits upon psychosocial functioning. The correlational design of this study precludes definitive statements regarding the temporal nature of the relationship. Additional research, including longitudinal research and replicatory studies, will be needed to further investigate the developmental consequences of executive functioning impairment.
Date: August 2001
Creator: Falla, Karen M.
System: The UNT Digital Library

Simulating Statistical Power Curves with the Bootstrap and Robust Estimation

Access: Use of this item is restricted to the UNT Community
Power and effect size analysis are important methods in the psychological sciences. It is well known that classical statistical tests are not robust with respect to power and type II error. However, relatively little attention has been paid in the psychological literature to the effect that non-normality and outliers have on the power of a given statistical test (Wilcox, 1998). Robust measures of location exist that provide much more powerful tests of statistical hypotheses, but their usefulness in power estimation for sample size selection, with real data, is largely unknown. Furthermore, practical approaches to power planning (Cohen, 1988) usually focus on normal theory settings and in general do not make available nonparametric approaches to power and effect size estimation. Beran (1986) proved that it is possible to nonparametrically estimate power for a given statistical test using bootstrap methods (Efron, 1993). However, this method is not widely known or utilized in data analysis settings. This research study examined the practical importance of combining robust measures of location with nonparametric power analysis. Simulation and analysis of real world data sets are used. The present study found that: 1) bootstrap confidence intervals using Mestimators gave shorter confidence intervals than the normal theory counterpart …
Date: August 2001
Creator: Herrington, Richard S.
System: The UNT Digital Library

A study of freshman interest groups and leadership practices at Texas Woman's University

Access: Use of this item is restricted to the UNT Community
This study investigated the level of leadership practices and retention rates of freshman students at Texas Woman's University. The data for the study were collected using the Leadership Practices Inventory, Student Version. The sample for the study consisted of 151 freshman students. The students were each placed in one of three control groups. Group A students (the treatment group) were in the Neighbors Educated Together Program (NET). Group B students (control group) were in one of two university-sponsored programs (COLORS or University 1000), and Group C students (control group) were the residual group of first-time college freshmen. These three groups were surveyed prior to their participation in the NET program or a university-sponsored program and again at the end of 14 weeks. In addition, retention rates were examined on the 12 class day of the spring semester. The study found statistically significant differences (p <. 05) on the pretests and posttests between Group C, residual students, and the other two groups on the Enabling the Followers to Act subscale, the Inspiring a Shared Vision subscale, and Encouraging the Heart subscale. Group A, NET students, and Group B, COLORS/University 1000 students, showed no statistically significant differences between groups. The difference from …
Date: August 2001
Creator: Mendez-Grant, Monica S
System: The UNT Digital Library

Submerged wood inhabiting macoinvertebrates of the Elm Fork of the Trinity River, Texas: Assemblage analyses, comparisons to the benthic fauna, and a study of Cyrnellus fraternus (Trichoptera: Polycentropodidae)

Access: Use of this item is restricted to the UNT Community
Taxonomic composition and spatio-temporal variability of macroinvertebrates inhabiting snags were examined from an 8-km segment of the Elm Fork of the Trinity River. Seventy-seven macroinvertebrate taxa were collected from submerged wood during the study. Assemblages were highly variable spatially and temporally, especially among seasons. An ordination of species and environment did not find snag taxa to have striking correlations with many of the selected environmental variables, although there were some trends in flow-mediated species distributions. There were significant seasonal differences in the abundances of some taxa, particularly among the Chironomidae (Diptera). The Tribe Orthocladiini was numerically abundant during the winter, while the Tribes Chironomini and Tanytarsini dominated the summer and autumn. Additionally, this study included a secondary production and microdistribution analysis of a population of the caddisfly Cyrnellus fraternus. Distributions of C. fraternus were restricted to snags, the most stable substratum for retreat building and for resisting periodic high waters. Larvae were not found in the soft sand and mud benthic habitats near submerged wood. The insects were multivoltine with a minimum of three generations per year. Pupae were collected July through September and adults emerged from May through October. The population overwintered as larvae. Estimated annual production was 1,015.4 …
Date: August 2001
Creator: Johnson, Zane B.
System: The UNT Digital Library