UNT Theses and Dissertations - 18,417 Matching Results

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Source Apportionment Analysis of Measured Volatile Organic Compounds in Corpus Christi, Texas

Description: Corpus Christi among of the largest industrialized coastal urban areas in Texas. The strategic location of the city along the Gulf of Mexico allows for many important industries and an international business to be located. The cluster of industries and businesses in the region contribute to the air pollution from emissions that are harmful to the environment and to the people living in and visiting the area. Volatile organic compounds (VOC) constitute an important class of pollutants measured in the area. The automated gas chromatography (Auto GC) data was collected from Texas Commission of Environmental Quality (TCEQ) and source apportionment analysis was conducted on this data to identify key sources of VOC affecting this study region. EPA PMF 3.0 was employed in this sources apportionment study of measured VOC concentration during 2005 - 2012 in Corpus Christi, Texas. The study identified nine optimal factors (Source) that could explain the concentration of VOC at two urbane monitoring sites in the study region. Natural gas was found to be the largest contributor of VOC in the area, followed by gasoline and vehicular exhaust. Diesel was the third highest contributor with emissions from manufacturing and combustion processes. Refineries gases and evaporative fugitive emissions were other major contributors in the area; Flaring operations, solvents, and petrochemicals also impacted the measured VOC in the urban area. It was noted that he measured VOC concentrations were significantly influenced by the economic downturn in the region and this was highlighted in the annual trends of the apportioned VOC.
Date: May 2014
Creator: Abood, Ahmed T.
Partner: UNT Libraries

Boosting for Learning From Imbalanced, Multiclass Data Sets

Description: In many real-world applications, it is common to have uneven number of examples among multiple classes. The data imbalance, however, usually complicates the learning process, especially for the minority classes, and results in deteriorated performance. Boosting methods were proposed to handle the imbalance problem. These methods need elongated training time and require diversity among the classifiers of the ensemble to achieve improved performance. Additionally, extending the boosting method to handle multi-class data sets is not straightforward. Examples of applications that suffer from imbalanced multi-class data can be found in face recognition, where tens of classes exist, and in capsule endoscopy, which suffers massive imbalance between the classes. This dissertation introduces RegBoost, a new boosting framework to address the imbalanced, multi-class problems. This method applies a weighted stratified sampling technique and incorporates a regularization term that accommodates multi-class data sets and automatically determines the error bound of each base classifier. The regularization parameter penalizes the classifier when it misclassifies instances that were correctly classified in the previous iteration. The parameter additionally reduces the bias towards majority classes. Experiments are conducted using 12 diverse data sets with moderate to high imbalance ratios. The results demonstrate superior performance of the proposed method compared to several state-of-the-art algorithms for imbalanced, multi-class classification problems. More importantly, the sensitivity improvement of the minority classes using RegBoost is accompanied with the improvement of the overall accuracy for all classes. With unpredictability regularization, a diverse group of classifiers are created and the maximum accuracy improvement reaches above 24%. Using stratified undersampling, RegBoost exhibits the best efficiency. The reduction in computational cost is significant reaching above 50%. As the volume of training data increase, the gain of efficiency with the proposed method becomes more significant.
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Date: December 2013
Creator: Abouelenien, Mohamed
Partner: UNT Libraries

Finitness and Verb-Raising in Second Language Acquisition of French by Native Speakers of Moroccan Arabic

Description: In this thesis, the three hypotheses on the nature of early L2 acquisition (the Full Transfer/Full Access view of Schwartz and Sprouse (e.g., 1996), the Minimal Trees view of Vainikka and Young-Scholten (e.g., 1996), and the Valueless Features view of Eubank (e.g., 1996)), are discussed. Analysis of the early French production by two native speakers of Moroccan Arabic is done to determine if the L1 grammar is transferred onto the L2 grammar. In particular, the phenomena of verb-raising (as determined by the verb's position vis-a-vis negation) and finiteness are examined. The results of this study indicate that the relevant structures of Moroccan Arabic do not transfer onto the emerging French grammar.
Date: August 1996
Creator: Aboutaj, Heidi H. (Heidi Huttar)
Partner: UNT Libraries

Development of a Cost Effective Wireless Sensor System for Indoor Air Quality Monitoring Applications

Description: Poor air quality can greatly affect the public health. Research studies indicate that indoor air can be more polluted than the outdoor air. An indoor air quality monitoring system will help to create an awareness of the quality of air inside which will eventually help in improving it. The objective of this research is to develop a low cost wireless sensor system for indoor air quality monitoring. The major cost reduction of the system is achieved by using low priced sensors. Interface circuits had to be designed to make these sensors more accurate. The system is capable of measuring carbon dioxide, carbon monoxide, ozone, temperature, humidity and volatile organic compounds. The prototype sensor node modules were developed. The sensor nodes were the connected together by Zigbee network. The nodes were developed in such a way that it is compact in size and wireless connection of sensor nodes enable to collect air quality data from multiple locations simultaneously. The collected data was stored in a computer. We employed linear least-square approach for the calibration of each sensor to derive a conversion formula for converting the sensor readings to engineering units. The system was tested with different pollutants and data collected was compared with a professional grade monitoring system for analyzing its performance. The results indicated that the data from our system matched quite well with the professional grade monitoring system.
Date: May 2014
Creator: Abraham, Sherin
Partner: UNT Libraries

An Art Program Utilizing Discarded Materials in the Improvement of Interiors of Homes of Children in a Low Income Group

Description: The problem with which this investigation is concerned is that of planning and carrying out an art program in which a particular group of students in a low income group, by utilizing discarded and inexpensive materials, can create useful and satisfying objects for the improvement of their home interiors.
Date: January 1960
Creator: Abram, W. B.
Partner: UNT Libraries

Proton-Induced L-shell X-Rays of Pr, Sm, Eu, Gd, and Dy

Description: Characteristic L-shell x rays of the five rare earths Pr, Sm, Eu, Gd, and Dy were studied in this work. The x rays were produced by ionization from 0.3 to 2.0 MeV protons from the 2.0 MV Van de Graaff at North Texas State University. Total L-shell ionization and x-ray production cross sections were measured for Sm and compared to the BEA, CBEA and PWBA theories. Total L-shell ionization cross sections were measured for Pr, Eu, Gd, and Dy and compared to the BEA, CBEA, and PWBA. The CBEA and PWBA fit the samarium data well for both ionization and x-ray production cross sections. The BEA was generally 40 per cent lower than the data. The CBEA and the PWBA also fit the ionization cross section data for Pr, Eu, Gd and Dy, while the BEA was generally 40 per cent lower than the data.
Date: August 1974
Creator: Abrath, Frederick G.
Partner: UNT Libraries

Diphenyloxazole Metabolism by Aryl Hydrocarbon Hydroxylase

Description: 2,5-Diphenyloxazole (PPO) was tested as a potential alternate inducer for the aryl hydrocarbon hydroxylase (AHH) system. Its apparent lack. of carcinogenicity and toxicity provide a possible system for investigation of enzyme systems related to chemical carcinogenesis without exposure of the researcher to potent carcinogenic compounds. These studies found PPO to be an inducer of AHH in cultured human lymphocytes. When PPO was utilized as a substrate for the AHH assay system, the major metabolites produced were strongly fluorescent. A simple fluorometric assay was developed which employed PPO as the substrate and which measured constitutive activity more efficiently than similar assays using benzo(a)pyrene as the substrate. Quantitation of both basal and induced lymphocyte AHH metabolism of PPO may be applicable to human population studies and may provide a tool to determine possible genetic variables with respect to carcinogen metabolism related to cancer risk.
Date: December 1976
Creator: Abreu, Mary E.
Partner: UNT Libraries

Immunoflorescence as a method for the rapid identification of streptococcus faecalis in water

Description: The serum of an immunized animal will contain antibodies referred to as agglutinins, precipitins, opsonins, bacteriolysins, or complement-fixing antibodies (Zinsser 1952). The presence of such antibodies may be demonstrated in the laboratory, the type of reaction depending on the circumstance and the laboratory manipulation employed. Regardless of the specific serolological method utilized, the manifestation of the antigen-antibody reaction is the visible observation that such a combination has occurred.
Date: August 1970
Creator: Abshire, Robert Louis
Partner: UNT Libraries

Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms

Description: In this study we applied ultra-short laser pulses on a biological sample (Arabidopsis), in order to cut it precisely in a square pattern and subsequently use it for studying stress generation mechanisms. For this purpose, we utilized femtosecond laser pulses at 100 fs pulse width and 80 MHz repetition rate. We took two processing parameters into consideration such as laser power, laser exposure time which is related to the stage speed. Therefore, we were able to find the laser optimum conditions for ablation of biological tissues. The mutant and wildtype (control) obtained from laser cutting with a size of 500 µm × 500 µm were directly transferred (in-situ with laser cutting) into a microfabricated chamber containing ~500 nanoliters deionized water for measuring ion conductivity. The ion conductivity is a signature of cell-death mechanisms caused by various stresses. A light with intensity of 100 µmol was exposed to the samples for 2 hours and 20 minutes as a source of stress. A quantitative electrical analysis with high accuracy was assured by utilizing a microchamber, which enables a measurement in nanoliter volume. We measured the impedance which is reciprocal of conductivity using a lock-in amplifier and a precise current source at frequency of 130 Hz. Initially high impedance of mutant sample tended to drop within 2 hours and finally approached the constant value which signified that the cell death mechanism was complete. However, the wildtype sample demonstrated approximately constant impedance (conductivity) during the experiment.
Date: August 2010
Creator: Abtahi, Seyed Ali
Partner: UNT Libraries

Application of Synthetic Peptides as Substrates for Reversible Phosphorylation

Description: Two highly homologous synthetic peptides MLC(3-13) (K-R-A-K-A-K-T-TK-K-R-G) and MLC(5-13) (A-K-A-K-T-T-K-K-R-G) corresponding to the amino terminal amino acid sequence of smooth muscle myosin light chain were utilized as substrates for protein kinase C purified from murine lymphosarcoma tumors to determine the role of the primary amino acid sequence of protein kinase C substrates in defining the lipid (phosphatidyl serine and diacylglycerol) requirements for the activation of the enzyme. Removal of the basic residues lysine and arginine from the amino terminus of MLC(3-13) did not have a significant effect on the Ka value of diacylglycerol. The binding of effector to calcium-protein kinase C appears to be random since binding of one effector did not block the binding of the other.
Date: August 1992
Creator: Abukhalaf, Imad Kazem
Partner: UNT Libraries

Corporate Christians and Terrible Turks: Economics, Aesthetics, and the Representation of Empire in the Early British Travel Narrative, 1630 - 1780

Description: This dissertation examines the evolution of the early English travel narrative as it relates to the development and application of mercantilist economic practices, theories of aesthetic representation, and discourses of gender and narrative authority. I attempt to redress an imbalance in critical work on pre-colonialism and colonialism, which has tended to focus either on the Renaissance, as exemplified by the works of critics such as Stephen Greenblatt and John Gillies, or on the later eighteenth and early nineteenth centuries, as in the work of scholars such as Srinivas Aravamudan and Edward Said. This critical gap has left early travel narratives by Sir Francis Moore, Jonathan Harris, Penelope Aubin, and others largely neglected. These early writers, I argue, adapted the conventions of the travel narrative while relying on the authority of contemporary commercial practices. The early English travelers modified contemporary conventions of aesthetic representation by formulating their descriptions of non-European cultures in terms of the economic and political conventions and rivalries of the early eighteenth century. Early English travel literature, I demonstrate, functioned as a politically motivated medium that served both as a marker of authenticity, justifying the colonial and imperial ventures that would flourish in the nineteenth century, and as a forum for experimentation with English notions of gender and narrative authority.
Date: December 2003
Creator: Abunasser, Rima Jamil
Partner: UNT Libraries

Studies on the mechanism of protection by carotenoids against photodynamic killing in Curtobacterium flaccumfaciens pathover poinsettiae

Description: The mechanism of protection by carotenoids against photodynamic killing in Curtobacterium flaccumfaciens pathover poinsettiae (C. poinsettae)was studied using pigment mutants isolated by treatment with nitrosuguandine and DNA gyrase inhibitors.
Date: August 1992
Creator: Abusada, Gabi M. (Gabi Michael)
Partner: UNT Libraries

Exploratory Analysis of Social E-health Behavior

Description: Extant literature has documented well that people seek health information via the internet as patients and consumers. Much less, however, is known about interaction and creation behaviors in the development of new online health information and knowledge. More specifically, generalizable sociodemographic data on who engages in this online health behavior via social media is lacking in the sociological literature. The term “social e-health” is introduced to emphasize the difference between seeking behaviors and interaction and creation behaviors. A 2010 dataset of a large nationally representative and randomly sampled telephone survey made freely available from the Pew Research Center is used to examine social e-health behavior according to respondents’ sociodemographics. The dependent variable of social e-health behavior is measured by 13 survey questions from the survey. Gender, race, ethnicity, age, education, and income are used as independent variables. Logistic regression analysis was used to determine the odds of engagement in social e-health behavior based on the sociodemographic predictors. The social determinants of health and digital divide frameworks are used to help explain why socioeconomic variances exist in social e-health behavior. The findings of the current study suggest that predictable sociodemographic patterns along the dimensions of gender, race, age, education, and income exist for those who report engaging in social e-health behavior. This study is important because it underscores the fact that engagement in social e-health behavior is differentially distributed in the general U.S. population according to patterned sociodemographics.
Date: May 2014
Creator: Acadia, Spencer
Partner: UNT Libraries

Cooperative Strategy and Sources of Knowledge Integration Capability and Innovation: A Relational View

Description: Faced with the challenges to addressing the novelties of the changing business environments (e.g., new customer requirement, changes in customers taste and preferences, the introduction of new products or services by competitors), organizations seek to build collaboration among their employees who possess complementary knowledge. Integrating complementary knowledge enhances employees' ability to address environmental challenges and foster innovation. Despite the importance of knowledge integration for innovation, integration of such knowledge becomes difficult when employees lack a shared understanding of knowledge, and when the knowledge is newly generated. Because new knowledge is tacit in nature and highly personal to a particular individual, it is difficult to articulate, making knowledge integration (KI) an arduous task. Lack of shared understanding, the presence of new knowledge, and lack of common interests in employees creates three types of knowledge boundaries – syntactic (information processing) boundaries, semantic (interpretive) boundaries, and pragmatic (political) boundaries. The presence of knowledge boundaries makes it difficult for employees to share and access their knowledge with each other. To overcome the challenges related to the knowledge boundaries, employees use boundary-spanning objects, which are common lexicons, common meaning, and common interests, to share and access their knowledge across the boundaries. Although prior studies have emphasized the importance of knowledge integration of various knowledge sources for innovations, examinations of what enhances KI capability of employees for organizational innovation remain limited. In addition, apart from Carlile, (2004) and Franco (2013), which are both case studies, other studies that examine the role of boundary spanning objects for knowledge integration are missing. The knowledge management literature also fails to measures (the success of common lexicons, common meaning, and common interests for achieving KI capability) boundary spanning objects. Therefore, in this study, new measurement items of boundary spanning objects and novelty are developed to test the hypotheses. A survey-based ...
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Date: August 2016
Creator: Acharya, Chandan
Partner: UNT Libraries

Love Attitudes and Marital Adjustment Through Five Stages of the Marital Life-Cycle in Protestant Nigerian Society

Description: This study examined the relationship between love attitude and marital adjustment across five stages of the marital life-cycle in Nigerian society. The subjects for this study were 202 volunteers from six protestant churches representing six cities in the southern part of Nigeria. An average of 20 couples were representatives of each of the five marital life-cycles. Each of the subjects completed the Love Attitude Inventory (LAI), and the Marital Adjustment Test (short form) (MAT). Wilk's multivariate analysis revealed no significant differences between husbands' and wives' love attitude and marital adjustment across the five stages of the marital life cycle. Multivariate analysis split-plot 5.2 with repeated measures revealed no significant difference for the total sample among the groups, but indicated a significant difference between love attitude and marital adjustment for the total sample using sex as a factor. A univariate test of the MAT and LAI indicated that the MAT accounted for the difference. A canonical correlation indicated a significant positive relationship between husbands1 and wives' marital adjustment and love attitude within each of the five groups. The findings suggest that husbands and wives included in this study have a good understanding of their roles in the marriage relationship and that the partners have general agreement regarding those roles. The marriage partners apparently have strong influences on each other's perceptions of love attitude and marital adjustment.
Date: December 1988
Creator: Acho, Onyebuchi S. (Onyebuchi Sunday)
Partner: UNT Libraries

Haves, Halves, and Have-Nots: School Libraries and Student Achievement in California

Description: This descriptive, non-experimental study examines the strength of the relationship between California school library media programs and student achievement, using data from California criterion-referenced state-wide tests, publically available school and community demographic data, and a state survey of school library programs. Results indicate a substantial discrepancy in library staffing levels from the elementary grades through the high schools. Nevertheless, statistically significant correlations were found between certificated staffing levels and student achievement at each grade. Significant correlations persisted at the elementary and middle school when controlling for five of six school and community variables, and at the high school when controlling for all six of those variables. Bivariate correlations between total staffing and student achievement were significant at both the middle school and high school level when controlling for all school and community variables. Generally, the strength of the correlations between both certificated and total staffing tended to increase with grade level; at the high school level, correlations were among the strongest reported in any statewide study to date. There was a significant positive relationship between a majority of the 21 library services regularly provided and student achievement at all levels. Total library services were significantly related to student achievement at all levels when controlling for all school and community variables. In multiple regression analyses, there was an increasingly stronger relationship between total library programs and student achievement by grade level when controlling for all school and community variables. At every level, certificated and total staffing levels were associated with the strength of library program elements. The findings from this study confirm a host of prior research on the relationship between school libraries and student achievement and point to inequitable access to school library services in California. Results from this study might also provide a baseline of data for qualitative research ...
Date: December 2008
Creator: Achterman, Douglas L.
Partner: UNT Libraries

A Study to Determine the Relationship of Versatile Behavior to Individual Demographics, Job Characteristics, Organizational Climate Performance Feedback and Job Satisfaction

Description: The behavioral characteristics of leaders have been subjects of study for centuries. The scope of these studies has grown to encompass task analysis, follower needs and situational requirements. Current leadership theories consistently recognize the need for a successful leader to adjust behavior to meet the needs of the task, followers and situation. The problem of this research is to define this ability to modify one's behavior, measure it and test its relationship to demographic and job characteristics. The purpose of this study is to evaluate the correlation of individuals" ability to modify their behavior to job function, hierarchy, climate, feedback, satisfaction and their demographic characteristics. The hypotheses held that high ability to modify behavior would correlate positively with job characteristics, climate, feedback and satisfaction and show no correlation to individual demographics. Data were collected through the administration of three research instruments to 138 managers of three business firms. The instruments were the Participant Data Form providing job and demographic characteristics, Descriptive Adjective Questionnaire measuring an individual ability to modify behavior, and Climate and Satisfaction Evaluation Index measuring climate, feedback and satisfaction. Perason's correlation coefficients were calculated to identify possible relationship between the manager's ability to modify behavior, called versatility, and all other independent variables, and linear and multiple regressions were utilized to verify the relationship. No significant statistical correlation was found. Conclusions are that the ability of a manager to vary behavior does not influence job climate, feedback or satisfaction, that the versatile behavior is not derived from job or demographic characteristics, and that job satisfaction is directly and positively related to performance feedback and climate.
Date: May 1988
Creator: Ackerman, Raymond L. (Ramond Lorens)
Partner: UNT Libraries