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Academic Achievement: Examining the Impact of Community Type at a Small Liberal Arts College in Texas (open access)

Academic Achievement: Examining the Impact of Community Type at a Small Liberal Arts College in Texas

Hierarchical regression was used to determine if high school community type is an effective predictor of academic success when controlling for demographics, prior academic achievement, socioeconomic status, and current commitment or work habits for students entering Austin College in 1992,1993, and 1994 . Findings revealed that there is a relationship between attending high school in community types of rural and independent town controlling for the effects of SAT scores, high school rank, sex, and late application deposit on first semester grade point average.
Date: August 1995
Creator: Rutherford, Janis Pruitt
System: The UNT Digital Library
An adaptive level set method (open access)

An adaptive level set method

This thesis describes a new method for the numerical solution of partial differential equations of the parabolic type on an adaptively refined mesh in two or more spatial dimensions. The method is motivated and developed in the context of the level set formulation for the curvature dependent propagation of surfaces in three dimensions. In that setting, it realizes the multiple advantages of decreased computational effort, localized accuracy enhancement, and compatibility with problems containing a range of length scales.
Date: December 1, 1995
Creator: Milne, R. B.
System: The UNT Digital Library
Adolescent Pregnancy: Voices Heard in the Everyday Lives of Pregnant Teenagers (open access)

Adolescent Pregnancy: Voices Heard in the Everyday Lives of Pregnant Teenagers

The purpose of this study is to examine the problems that pregnant teenagers encounter at school and at home while they are trying to complete their high school education. Data were collected by in-depth interviews. Twenty pregnant adolescents, who were between the ages of 15 through 18, and were participants in a special teen pregnancy program were interviewed. The major findings in this study included the respondents': 1) unstable family life histories, 2) denial that they were pregnant, 3) need for self-identity as an adult, 4) conflict with parents and 5) motivation to complete their high school education. This study points to the need for more research on the problems that pregnant adolescents encounter in their everyday lives.
Date: December 1995
Creator: Oviedo, Sonia
System: The UNT Digital Library
An Algorithm for the PLA Equivalence Problem (open access)

An Algorithm for the PLA Equivalence Problem

The Programmable Logic Array (PLA) has been widely used in the design of VLSI circuits and systems because of its regularity, flexibility, and simplicity. The equivalence problem is typically to verify that the final description of a circuit is functionally equivalent to its initial description. Verifying the functional equivalence of two descriptions is equivalent to proving their logical equivalence. This problem of pure logic is essential to circuit design. The most widely used technique to solve the problem is based on Binary Decision Diagram or BDD, proposed by Bryant in 1986. Unfortunately, BDD requires too much time and space to represent moderately large circuits for equivalence testing. We design and implement a new algorithm called the Cover-Merge Algorithm for the equivalence problem based on a divide-and-conquer strategy using the concept of cover and a derivational method. We prove that the algorithm is sound and complete. Because of the NP-completeness of the problem, we emphasize simplifications to reduce the search space or to avoid redundant computations. Simplification techniques are incorporated into the algorithm as an essential part to speed up the the derivation process. Two different sets of heuristics are developed for two opposite goals: one for the proof of equivalence …
Date: December 1995
Creator: Moon, Gyo Sik
System: The UNT Digital Library
Algorithms for biomagnetic source imaging with prior anatomical and physiological information (open access)

Algorithms for biomagnetic source imaging with prior anatomical and physiological information

This dissertation derives a new method for estimating current source amplitudes in the brain and heart from external magnetic field measurements and prior knowledge about the probable source positions and amplitudes. The minimum mean square error estimator for the linear inverse problem with statistical prior information was derived and is called the optimal constrained linear inverse method (OCLIM). OCLIM includes as special cases the Shim-Cho weighted pseudoinverse and Wiener estimators but allows more general priors and thus reduces the reconstruction error. Efficient algorithms were developed to compute the OCLIM estimate for instantaneous or time series data. The method was tested in a simulated neuromagnetic imaging problem with five simultaneously active sources on a grid of 387 possible source locations; all five sources were resolved, even though the true sources were not exactly at the modeled source positions and the true source statistics differed from the assumed statistics.
Date: December 1995
Creator: Hughett, P. W.
System: The UNT Digital Library
An Analysis of Factors That Influence the Involvement of Faculty in Learning Communities (open access)

An Analysis of Factors That Influence the Involvement of Faculty in Learning Communities

This research study attempts to analyze variables that influence the extent of faculty involvement in learning communities. A theoretical framework identifies three primary variable sets—faculty background, structural, and organizational/environmental.
Date: December 1995
Creator: Lapoint, Patricia A. (Patricia Ann)
System: The UNT Digital Library
Analysis of Memory Interference in Buffered Multi-processor Systems in Presence of Hot Spots and Favorite Memories (open access)

Analysis of Memory Interference in Buffered Multi-processor Systems in Presence of Hot Spots and Favorite Memories

In this thesis, a discrete Markov chain model for analyzing memory interference in multiprocessors, is presented.
Date: August 1995
Creator: Sen, Sanjoy Kumar
System: The UNT Digital Library
Analysis of offsite dose calculation methodology for a nuclear power reactor (open access)

Analysis of offsite dose calculation methodology for a nuclear power reactor

This technical study reviews the methodology for calculating offsite dose estimates as described in the offsite dose calculation manual (ODCM) for Pennsylvania Power and Light - Susquehanna Steam Electric Station (SSES). An evaluation of the SSES ODCM dose assessment methodology indicates that it conforms with methodology accepted by the US Nuclear Regulatory Commission (NRC). Using 1993 SSES effluent data, dose estimates are calculated according to SSES ODCM methodology and compared to the dose estimates calculated according to SSES ODCM and the computer model used to produce the reported 1993 dose estimates. The 1993 SSES dose estimates are based on the axioms of Publication 2 of the International Commission of Radiological Protection (ICRP). SSES Dose estimates based on the axioms of ICRP Publication 26 and 30 reveal the total body estimates to be the most affected.
Date: December 31, 1995
Creator: Moser, D.M.
System: The UNT Digital Library
Analysis of stray radiation produced by the advanced light source (1.9 GeV synchrotron radiation source) at Lawrence Berkeley Laboratory (open access)

Analysis of stray radiation produced by the advanced light source (1.9 GeV synchrotron radiation source) at Lawrence Berkeley Laboratory

The yearly environmental dose equivalent likely to result at the closest site boundary from the Advanced Light Source was determined by generating multiple linear regressions. The independent variables comprised quantified accelerator operating parameters and measurements from synchronized, in-close (outside shielding prior to significant atmospheric scattering), state-of-the-art neutron remmeters and photon G-M tubes. Neutron regression models were more successful than photon models due to lower relative background radiation and redundant detectors at the site boundary. As expected, Storage Ring Beam Fill and Beam Crashes produced radiation at a higher rate than gradual Beam Decay; however, only the latter did not include zero in its 95% confidence interval. By summing for all three accelerator operating modes, a combined yearly DE of 4.3 mRem/yr with a 90% CI of (0.04-8.63) was obtained. These results fall below the DOE reporting level of 10 mRem/yr and suggest repeating the study with improved experimental conditions.
Date: December 31, 1995
Creator: Ajemian, R. C.
System: The UNT Digital Library
An Analysis of the Use of Gift Annuity Agreements at Selected United States Colleges and Universities for the Period 1988-93 (open access)

An Analysis of the Use of Gift Annuity Agreements at Selected United States Colleges and Universities for the Period 1988-93

The objective of this research was to describe the extent to which Gift Annuity Agreements were used by United States higher education institutions in raising private philanthropic support during the period 1988-93.
Date: August 1995
Creator: McIntosh, Clifford Joe
System: The UNT Digital Library
Anatomy of Loss (open access)

Anatomy of Loss

Anatomy of Loss contains a foreword, which discusses the place of autobiography in fiction, and five original short stories.
Date: August 1995
Creator: Behlen, Shawn Lee
System: The UNT Digital Library
Anisotropic superconducting and normal state magnetic properties of single crystals of RNi*2*B*2*C compounds (R = Y, Gd, Dy, Ho, Er, and Tm) (open access)

Anisotropic superconducting and normal state magnetic properties of single crystals of RNi*2*B*2*C compounds (R = Y, Gd, Dy, Ho, Er, and Tm)

The interaction of superconductivity with magnetism has been one of the most interesting and important phenomena in solid state physics since the 1950`s when small amounts of magnetic impurities were incorporated in superconductors. The discovery of the magnetic superconductors RNi{sub 2}B{sub 2}C (R = rare earth, Y) offers a new system to study this interaction. The wide ranges of superconducting transition (T{sub c}) and antiferromagnetic (AF) ordering temperatures (T{sub N}) (0 K {le} T{sub c} {le} 16 K, 0 K {le} T{sub N} {le} 20 K) give a good opportunity to observe a variety of interesting phenomena. Single crystals of high quality with appropriate size and mass are crucial in examining the anisotropic intrinsic properties. Single crystals have been grown successfully by an unusual high temperature flux method and characterized thoroughly by X-ray, electrical transport, magnetization, neutron scattering, scanning electron microscopy, and other measurements.
Date: November 1, 1995
Creator: Cho, B.
System: The UNT Digital Library
Anxiety, Locus of Control and Stress in Adoptive and Biological Parents of Adolescents (open access)

Anxiety, Locus of Control and Stress in Adoptive and Biological Parents of Adolescents

The purpose of this study was to critically examine differences in levels of anxiety, locus of control and stress between adoptive and biological parents of adolescents.
Date: December 1995
Creator: Larussa, Thomas K. (Thomas Keith)
System: The UNT Digital Library
Application of a-Si:H radiation detectors in medical imaging (open access)

Application of a-Si:H radiation detectors in medical imaging

Monte Carlo simulations of a proposed a-Si:H-based current-integrating gamma camera were performed. The analysis showed that the intrinsic resolution of such a camera was 1 {approximately} 2.5 mm, which is somewhat better than that of a conventional gamma camera, and that the greater blurring, due to the detection of scattered {gamma}-rays, could be reduced considerably by image restoration techniques. This proposed gamma camera would be useful for imaging shallow organs such as the thyroid. Prototype charge-storage a-Si:H pixel detectors for such a camera were designed, constructed and tested. The detectors could store signal charge as long as 5 min at {minus}26C. The thermal generation current in reverse biased a-Si:H p-i-n photodetectors was investigated, and the Poole-Frenkel effect was found to be the most significant source of the thermal generation current. Based on the Poole-Frenkel effect, voltage- and time-dependent thermal generation current was modeled. Using the model, the operating conditions of the proposed a-Si:H gamma camera, such as the operating temperature, the operating bias and the {gamma}-scan period, could be predicted. The transient photoconductive gain mechanism in various a-Si:H devices was investigated for applications in digital radiography. Using the a-Si:H photoconductors in n-i-n configuration in pixel arrays, enhancement in signal collection …
Date: June 1, 1995
Creator: Lee, Hyoung-Koo
System: The UNT Digital Library
Application of seismic tomographic techniques in the investigation of geothermal systems (open access)

Application of seismic tomographic techniques in the investigation of geothermal systems

The utility of microearthquake data for characterizing the Northwest Geysers geothermal field and the Long Valley Caldera (LVC) was investigated. Three-dimensional (3-D) P- and S-wave seismic velocity models were estimated for the Coldwater Creek Steam Field (CCSF) in the Northwest Geysers region. Hypocenters relocated using these 3-D models appear to be associated with the steam producing zone, with a deeper cluster of hypocenters beneath an active injection well. Spatial and temporal patterns of seismicity exhibit strong correlation with geothermal exploitation. A 3-D differential attenuation model was also developed for the CCSF from spectral ratios corrected for strong site effects. High-velocity anomalies and low attenuation in the near surface correspond to Franciscan metagraywacke and greenstone units. Microearthquakes recorded at seismographic stations located near the metagraywacke unit exhibit high corner frequencies. Low-velocity anomalies and higher attenuation in the near surface are associated with sections of Franciscan melange. Near-surface high attenuation and high Vp/Vs are interpreted to indicate liquid-saturated regions affected by meteoric recharge. High attenuation and low Vp/Vs marks the steam producing zone, suggesting undersaturation of the reservoir rocks. The extent of the high attenuation and low Vp/Vs anomalies suggest that the CCSF steam reservoir may extend northwestward beyond the known producing …
Date: May 1, 1995
Creator: Romero, A. E., Jr.
System: The UNT Digital Library
Application of the Environmental Protection Agency`s data quality objective process to environmental monitoring quality control (open access)

Application of the Environmental Protection Agency`s data quality objective process to environmental monitoring quality control

The United States Environmental Protection Agency`s (EPA) Data Quality Objectives (DQO) process was applied to two environmental monitoring networks for the purpose of optimizing field quality control sampling to give the highest quality monitoring data with minimal impact on resources. The DQO process, developed primarily to aid in cleanup and restoration activities, is a systematic approach to designing sampling, and analysis programs with improved efficiency, cost savings, and measureable and traceable data quality. The two monitoring- networks studied had not been subjected to the systematic review and analysis of the DQO process defined by the EPA. The two monitoring networks studied had relied upon field duplicates or replicates as the main source of field quality control data. Sometimes, both duplicate and routine sample were analyzed by the same analytical laboratory; at other times they were analyzed by different laboratories. This study identified some potential inconsistencies between analytical data and reporting limits from two different laboratories. Application of the EPA DQO process resulted in recommendations for changes in the field quality control sampling program, allowed new insight into the monitoring data, and raised several issues that should be the subject of further investigation.
Date: November 1, 1995
Creator: Garcia, L.M.
System: The UNT Digital Library
Applications of capillary electrophoresis and laser-induced fluorescence detection to the analysis of trace species: From single cells to single molecules (open access)

Applications of capillary electrophoresis and laser-induced fluorescence detection to the analysis of trace species: From single cells to single molecules

This Ph.D. Thesis describes several separation and detection schemes for the analysis of small volume and amount of samples, such as intracellular components and single enzymes developed during research. Indirect Laser-induced fluorescence detection and capillary electrophoresis were used to quantify lactate and pyruvate in single red blood cells. The assay of specific enzyme activities was achieved by monitoring the highly fluorescent enzymatic reaction product, NADH. LDH activity was found not to be a unique marker for diagnosis of leukemia. Reactions of single LDH-1 molecules were investigated by monitoring the reaction product with LIF detection.
Date: November 1, 1995
Creator: Qifeng, X.
System: The UNT Digital Library
Applications of Flavor Symmetry to the Phenomenology of Elementary Particles (open access)

Applications of Flavor Symmetry to the Phenomenology of Elementary Particles

Some applications of flavor symmetry are examined. Approximate flavor symmetries and their consequences in the MSSM (Minimal Supersymmetric Standard Model) are considered, and found to give natural values for the possible B- and L-violating couplings that are empirically acceptable, except for the case of proton decay. The coupling constants of SU(3) are calculated and used to parameterize the decays of the D mesons in broken flavor SU(3). The resulting couplings are used to estimate the long-distance contributions to D-meson mixing.
Date: May 1, 1995
Creator: Kaeding, T. A.
System: The UNT Digital Library
Applications of Reductive Analytical Techniques in the Phrygian Settings of the Orgelbüchlein by J.S. Bach (open access)

Applications of Reductive Analytical Techniques in the Phrygian Settings of the Orgelbüchlein by J.S. Bach

This study aims to two problematic aspects of the Phrygian mode: a. the development of a harmonic pattern at the cadence that differs from that of the other modes and of the major and minor modes as well; b. the observation that the Phrygian scale inverts all of the intervallic properties of the Major scale. The result of these two observations is that when the reductive techniques of Heinrich Schenker are applied in the Phrygian repertory, melodic and harmonic properties are brought into conflict with each other. However, application of alternative models of the Ursatz developed by Lori Burns has certain benefits for demonstrating musical properties in the Phrygian repertory.
Date: May 1995
Creator: Leite, Zilei de Oliveira
System: The UNT Digital Library
An Approach Towards the Total Synthesis of Clonostachydiol (open access)

An Approach Towards the Total Synthesis of Clonostachydiol

The syntheses of the unsymmetrical 14-membered bismacrolides have been reviewed. A total synthesis of clonostachydiol, the latest to join this family, has been attempted using trimethylsilyl acetylene as the builiding block and palladium catalyzed reactions for the formation of key bonds. The alkyne groups were introduced by Stille coupling of trimethylstannylethynyltrimethylsilane with an acid chloride for one fragment and by addition of lithiotrimethylsilyl acetylene to an aldehyde for the other. Lactic acid derivatives were chosen as starting materials for both fragments, thus introducing two of the chiral centers. The remaining stereocenters were introduced using stereoselective reductions of ketones.
Date: August 1995
Creator: Maiti, Tushar B. (Tushar Baran)
System: The UNT Digital Library
An Argument for the Reassessment of Stravinsky's Early Serial Compositions (open access)

An Argument for the Reassessment of Stravinsky's Early Serial Compositions

Between 1952 and 1957, Igor Stravinsky surprised the world of music by gradually incorporating serialism into his style of composition. Although Stravinsky still used the neo-classical trait of making strong references to the music of earlier periods, musical analyses of this transitional period have focused on serial aspects to the exclusion of anachronistic elements. Evidence of Stravinsky's possible use of musical structures adapted from earlier times is found in his consistent use of musical figures that are closely related to the cadences of the late Medieval and Renaissance eras. By fully addressing these neo-classical traits in future analyses, music theorists will gain an additional perspective, which is helpful in understanding the music of Stravinsky's transitional period.
Date: December 1995
Creator: Hughes, Timothy Stephen
System: The UNT Digital Library
The Arrangement of Ezra Pound's Personae (1926) : An Interpretive Application of Editorial and Critical Theory (open access)

The Arrangement of Ezra Pound's Personae (1926) : An Interpretive Application of Editorial and Critical Theory

Pound foregrounded the importance of "shaping" poetic books through particular arrangements of individual poems by using his ideogrammic method as the crucial organizational principle for constructing Personae (1926). Critics have long understood Pound's use of the ideogrammic method in individual poems, but have so far ignored his application of it to the structuring of poetic books and sequences. Lea Baechler and A. Walton Litz, the editors of a 1990 edition of Personae (1926), however, have moved a crucial section of poems, and their rearrangement of the original text both disregards evidence of authorial intention and obscures Pound's innovative principles for arranging his shorter poems into meaningful sequences.
Date: December 1995
Creator: Salchak, Stephen P. (Stephen Patrick)
System: The UNT Digital Library
Artists' Books: An Investigation Into Another Genre of Artistic Expression (open access)

Artists' Books: An Investigation Into Another Genre of Artistic Expression

For centuries, books have been a traditional way to display prints. Contemporary artists' books have become more than simply a method of displaying prints and have, in fact, become a relevant medium for artistic expression. It has been important to my work that each of my artist's books have functioned as a unified whole, all parts of complementing each other and strengthening the overall concept.
Date: August 1995
Creator: Zipfel, Karen K.
System: The UNT Digital Library
Assessing Regional Gully Erosion Risk: A Remote Sensing and Geographic Information Systems Approach (open access)

Assessing Regional Gully Erosion Risk: A Remote Sensing and Geographic Information Systems Approach

Gully erosion has been established as a major source of sediment pollution in the upper Trinity River watershed in north-central Texas. This fact, along with a lack of models appropriate for a large-area gully erosion analysis established a need for a gully erosion study in the upper Trinity basin. This thesis project attempted to address this need by deriving an index indicative of gully erosion risk using remote sensing and geographic information systems (GIS) methodology. In context of previous field studies, the coarse spatial resolution of the input GIS data layers presented a challenge to prediction of gully prone areas. However, the remote sensing/GIS approach was found to provide useful reconnaissance information on gully risk over large areas.
Date: August 1995
Creator: Sill, Paul E. (Paul Eric)
System: The UNT Digital Library