UNT Theses and Dissertations - 18,690 Matching Results

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Effects of Sertraline Exposure on Fathead Minnow (Pimephales promelas) Steroidogenesis

Description: Sertraline is a selective serotonin reuptake inhibitor (SSRI) that is widely used for the treatment of depression and anxiety. Due to the abundant therapeutic use of sertraline, low levels have been detected in municipal wastewater effluents suggesting that aquatic organisms may be exposed. The purpose of this study was to evaluate the steroidogenic effects of sertraline on larval (FHM) and adult female fathead minnows (FFHM), Pimephales promelas. Larval FHM were exposed to 0.1, 1, and 10 µg/L sertraline for 28 days and analyzed via RT-qPCR for differential expression of 11β-Hydroxysteroid dehydrogenase (11β-HSD), 20β-Hydroxysteroid dehydrogenase (20β-HSD), aromatase (CYP19), and nuclear thyroid receptor alpha (TRα). FFHM were exposed to 3 or 10 µg/L sertraline for 7 days with the brain and ovary excised at exposure termination. Juvenile FHM exposed to 0.1 μg/L sertraline had a significant upregulation of both 20β-HSD and TRα. FFHM exposed to 10 µg/L sertraline had a significant upregulation of 11β-HSD expression in brain tissue, while no steroidogenic changes were observed in the FFHM ovary. Similarly, in FFHM brain tissue, CYP19 and 20β-HSD expression levels were significantly higher in fish exposed to 10µg/L sertraline compared to control. The significance of these findings with respect to survival, growth and reproduction are currently unknown, but represent future research needs.
Date: December 2014
Creator: Carty, Dennis R.
Partner: UNT Libraries

The Effects of Shaping and Instruction-based Procedures on Behavioral Variability during Acquisition and Extinction

Description: This study examined effects of two response acquisition procedures on topography of responding using the revealed operant technique and compared results to previous experiments on this topic. Subjects emitted 100 repetitions each of 4 response patterns on a continuous schedule of reinforcement. A 30-min extinction condition followed acquisition. One group of subjects learned the first response through a series of shaping steps designed to reduce acquisition variability. Another group of subjects was instructed in the correct response topography and was told there was no penalty for attempting other sequences. The first group of subjects produced high variability during extinction despite reduced variability in acquisition. The second group of subjects responded with moderate to high variability during extinction and little variability during acquisition. Most extinction responses for the first group were variations of the last pattern reinforced. Most extinction responses for the second group were repetitions of the last pattern reinforced.
Date: December 1999
Creator: McCary, Donald
Partner: UNT Libraries

The Effects of Shoe Modification on Transverse Tibial Rotation

Description: The purpose of this study was to evaluate the amount of change in transverse tibial rotation at the knee achieved through the use of shoe modification. In addition, an attempt to evaluate the Q-angle dynamically through the stance phase to reflect changes in transverse tibial rotation was made. Ten male subjects were filmed as they ran on a treadmill at a 2.82 m/sec pace and transverse tibial rotation data was collected simultaneously from an affixed electrogoniometer at the knee joint. The subjects were tested under three conditions: 1) barefoot, 2) running shoe, and 3) shoe plus standard orthotic. The results of the study showed that an unprescribed, standard orthotic was ineffective in changing foot pronation and transverse tibial rotation at the knee. It also showed that there was no relationship between leg-heel alignment measurements of pronation and electrogoniometric measurements of transverse tibial rotation. Q-angle measurements could not be obtained from the film date due to difficulty in visualizing body landmarks.
Date: August 1984
Creator: Trudelle, Elaine
Partner: UNT Libraries

The Effects of Shoe Type on Foot Functioning and Contact Pressures During Walking Performances

Description: The purpose of this study was to evaluate the functional effectiveness of a selection of women's walking shoes with particular attention being directed towards an assessment of specific shoe modifications which were included in a prototype model to theoretically reduce the undesirable characteristics associated with flexible shoes. Nine female subjects performed three trials for each of five shoe conditions. The prototype model decreased the encountered pressures and pressure integrals in the region of the second metatarsal-phalangeal joint. The use of the prototype shoe did not appear to unduly affect the gait of the subject.
Date: August 1982
Creator: Raley, Brenda F.
Partner: UNT Libraries

Effects of shoot X-irradiation on water uptake by single isolated roots of intact onion plants

Description: Using a micro-potometric method, it was found that x-irradiation (400 R-18 Kr) of the shoots of the onion plant Allium cepa will produce an immediate, pronounced (200%) and reversible enhancement of the water uptake by the shielded roots. Unfiltered X-irradiation (1200 R/min., 120 KVP, 5 ma) was delivered at right angles to the shoot.
Date: December 1974
Creator: Chang, Fu-Hsian
Partner: UNT Libraries

The Effects of Sign Language on the Vocal Responses of a Child with Autism.

Description: Sign language is an effective form of alternative communication for persons with autism and other developmental disabilities. Only a few studies have systematically measured the effects of sign language on the vocal responses of its users. This study employed a multiple baseline design to evaluate the effects of sign language on the vocal responses of a four-year-old boy with autism. Results indicate that a reinforcement contingency placed only on sign responses is inadequate for maintaining vocal responses. When a reinforcement contingency is placed on sign responses as well as vocal responses that the user is capable of emitting in verbal imitation, both sign and vocal responses are maintained. Results are discussed in terms of the need for a reinforcement contingency placed on vocal and sign responses, the effects of teaching procedures on response variability, and the need for future research to examine procedures utilized to teach sign language to persons within the developmental disabilities population.
Date: May 2004
Creator: Scarbro-McLaury, Jill
Partner: UNT Libraries

The Effects of Single and Combined Psyching up Strategies on Basketball Free-Throws and Leg Strength

Description: The present investigation was to determine if combining two mental preparation strategies would be more effective than a single strategy. In Experiment 1, subjects (n=40) performed basketball free-throws (20 shots) using one of these mental strategies: 1) imagery, 2) relaxation, 3)relaxation plus imagery, 4) placebo control. Results indicated a significant main effect with the imagery group performing significantly better than the placebo control group. In Experiment 2, subjects (n=40) performed five trials on an isokinetic leg-strength task using one of the following mental strategies: 1) preparatory arousal, 2) imagery, 3) preparatory arousal plus imagery, 4) placebo control. Results indicated a significant trials main effect with all subjects improving over time. State anxiety results indicated that the combination group exhibited higher levels of anxiety than all other conditions.
Date: August 1982
Creator: Chan, Roy Chin Ming
Partner: UNT Libraries

Effects of Single VI History on Human Concurrent VI VI Choice

Description: Two groups of human subjects pressed buttons on five different variable-interval (VI) reinforcement schedules presented for seven minutes each for 15 sessions. At session 16, the same VI schedules were programmed concurrently in each session either with or without a 5 s changeover delay (COD). The same schedule-correlated stimuli were employed in single and concurrent conditions. Two other groups responded on concurrent VI VI conditions from the first session with or without the COD. Response allocations under concurrent scheduling better approximated relative reinforcement frequencies when the COD was programmed. Subjects with single VI histories failed to match response and time allocations to reinforcement ratios better than subjects given no such history. Bidirectional cumulative records are discussed as a molecular data analysis technique.
Date: August 1992
Creator: Madden, Gregory J. (Gregory Jude)
Partner: UNT Libraries

Effects of Social Networks and Media on Pro-Environment Behaviors

Description: In this study, pro-environmental behaviors are investigated by studying if one's primary information sources about environmental issues either from their social network or the media influence this behavior. Data was collected from the 2002 Detroit Area Study with a total of 267 respondents. Three indexes were constructed to separately measure all seven pro-environment behavioral items, five conservation behavioral items, and two consumption behavioral items. A complex sample model was utilized in these analyses. Findings suggest that information sources are correlated to self-reported environmental behavior. As predicted, the people whose primary information source was social network were more likely to obtain higher scores on all three separate indexes than those individuals who primarily received information about environmental issues from the media.
Date: May 2011
Creator: Schuett, Jessica Lynn
Partner: UNT Libraries

The Effects of Social Structure on Social Movements in Turkey

Description: The main objective of this study is to provide an in-depth analysis the association between a set of social structural factors and the certain types of social movement events in Turkey. The changing nature and significance of social movements over time and space makes this study necessary to understand and explain new trends related to the parameters that constitute a backdrop for social movements. Social movements are a very common mechanism used by groups of people who decide to take action against an unfair socio-political system, usually an authoritarian government or dictatorship. This kind of reactions, seen in history before, gives birth to a more multidimensional understanding of the relationship between society and state policies. Understanding social movements depends on understanding our own societies, and the social environment in which they are developed. An effective way of understanding this type of social movements is to recognize the perceived concerns of discontented groups in relation to cultural, ideological, economic, and political institutions and values. Social movement events included in the study refers to collective activities organized by two or more people with the purpose of protesting public policies or of increasing public awareness about certain social issues related to human rights and freedoms, environment, feminism, etc. All these types of events are chased by police forces, and their concerns, statements, and activities are recorded.
Date: August 2014
Creator: Can, Ali
Partner: UNT Libraries

The Effects of Socio-Structural, Economic, and Race Considerations on Rates of Property Crime in the United States, 1958-1993

Description: This study investigates changes in rates of property crime in the United States from 1958 to 1993. Predictor variables include changes in rates of economic factors (inflation, technological/cyclical/frictional unemployment), arrest rates for property crimes disaggregated by race (ARPCDR), interaction of ARPCDR and technological unemployment, alcohol offenses, interaction of alcohol offenses and poverty, drug abuse violations, and interaction of drug abuse violations and poverty. Changes in poverty, population growth, and police presence are employed as control variables. The Beach-McKinnon Full Maximum- Likelihood EGLS AR1 Method (accompanied by residual analysis) is used to test seven hypotheses. Significant positive effects upon changes in aggregate property crime rates are found for five predictors: (a) inflation, (b) cyclical unemployment, (c) frictional unemployment, (d) the interaction of white arrest rates and technological unemployment, and (e) the interaction of rates of alcohol offenses and poverty. To explain changes in property crime rates, further research should decompose aggregate rates particularly those pertaining to the economy. Also, the relationship between the interaction of poverty and drug abuse violations, at the aggregate level, and changes in property crime rates should be clarified. This research has important policy implications related to the impact of social, economic, and educational issues on mainstream society and its criminal elements. Law makers should consider this type of research in all macro and micro-oriented policies.
Date: May 1996
Creator: Ralston, Roy W.
Partner: UNT Libraries

The Effects of Socioeconomic Status on Growth Rates in Academic Achievement.

Description: The purpose of the study was to examine the differences in academic growth rates as demonstrated on the TAKS test among students based on those who received free lunches, those who received reduced-price lunches, and those not economically disadvantaged. Texas Assessment of Knowledge and Skills (TAKS) for reading and mathematics scale scores were obtained from five Texas public school districts for students who were in 3rd grade in 2003, 4th grade in 2004, 5th grade in 2005, and 6th grade in 2006. The sample included almost 10,000 students. The data were analyzed using SPSS and HLM. SPSS was used to identify descriptive statistics. Due to the nested nature of the data, HLM was used to compare data on three levels- the test level, student level, and district level. Not economically disadvantaged students scored the highest on both TAKS reading and mathematics exams with a mean scale score of 2357 and 2316 respectively in 2003. Compared to the not economically disadvantaged students, students receiving reduce-priced lunches scored approximately 100 points lower, and lowest were the students receiving free lunches, scoring another 50 points below students receiving reduced-price lunches. The results revealed that while gaps in achievement exist between SES levels, little difference exists in the growth rates of the SES subgroups. The results of this study support the need for continued effort to decrease the gap between students who are not economically disadvantaged and those receiving free or reduced-price meals.
Date: December 2007
Creator: Chow, Priscilla En-Yi
Partner: UNT Libraries

The Effects of Specialized Skill Instruction on the Ability of Six-Grade Students to Solve Mathematical Word Problems

Description: The purpose of this study was to evaluate the effects of specialized skill instruction on the ability of sixth-grade students to solve mathematics word problems. Subjects were 578 sixth graders from eight elementary schools. Researcher-developed materials were used based on seven identified content strands. Specific sections of a widely used achievement test were used to identify ability groups in both reading and mathematics and served as the pretest and posttest measures.
Date: May 1984
Creator: Kuzminski, Pamela Plunkett
Partner: UNT Libraries

The Effects of Spouse Presence During Graded Exercise Testing on Psychological and Physiological Parameters in Cardiac Patients and Healthy Adults

Description: The direct effect of spouse presence during graded exercise testing on anxiety and performance has not been previously delineated. Therefore, the purposes of this study were to (a) ascertain if spouse presence during graded exercise testing affects state anxiety or physiological performance variables, and (b) determine differences in psychological status between cardiac patients and healthy adults.
Date: August 1987
Creator: Baylor, Krissa A.
Partner: UNT Libraries

The Effects of Stock Delistings on Firm Value, Risk, Market Liquidity and Market Integration: With Evidence on Wealth Effects from the Stock Exchanges of Malaysia and Singapore, Using GARCH

Description: This study examines the effects of delisting on firm value, risk and market liquidity. In a world where markets are becoming increasingly integrated, delistings may prove counter productive. We use the unique event, free from company specifics, that occurred on January 2, 1990 in the stock exchanges of Singapore and Malaysia to test for the above effects. On that day, dual listed companies were required to delist from the foreign stock exchange. We also use this event to test if the Singapore and Malaysia markets are globally integrated. Since financial data is found to show persistence in volatility, we model the return generating process in a generalized autoregressive conditionally heteroskedastic (GARCH) framework that takes into consideration changing volatility. For comparison purposes, OLS and Time-Deformation models are included. The study found delistings to decrease firm value, the size of which is related to how actively the stocks were previously traded on the foreign stock exchange. Risk levels increased following delistings. Nevertheless, thinly traded stocks showed significant changes in neither firm value nor riskiness. Further evidence of new listings to increase firm value was noted. Consistent with the political motive hypothesis, delisted stocks showed an increase in post-event volume, but however, lost relative liquidity compared with other stocks. While all portfolios considered show evidence for existence of conditional heteroskedasticity, comparison with standard OLS event-study results yields similar conclusions, although the return generating models with GARCH errors result in lower abnormal return variances. As for the time-deformation model, trading volume was found to be a good proxy for rate of information flow only for smaller capitalized stocks. Correlation and regression analyses showed that the Singapore and Malaysia markets are integrated to some degree with the international markets, such that a major delistings event between both markets did not change the pricing of risk ...
Date: May 1996
Creator: Meera, Ahamed Kameel
Partner: UNT Libraries

Effects of Strength on Selected Psychomotor Performances of Healthy and Frail Elderly Females

Description: The purpose of this study was to compare muscle strength and psychomotor performance measures in healthy (n = 18) and frail (n = 21) groups of elderly women utilizing movements requiring various amounts of strength and ballistic action. Subjects were community-dwelling females ranging in age from 66-92 years. Evaluations of functional assessment of motor skills and grip strength occurred. Psychomotor performance was measured through production of aiming movements on a Digitizing Tablet. RT, MT, and movement kinematics (e.g., peak velocity, deceleration, movement adjustments) were evaluated. Differences between groups were apparent in quantity and quality of movement. Healthy subjects were stronger and faster than frail subjects, producing smoother movements with fewer adjustments. Strength appears to differentially affect healthy and frail samples and merits further exploration.
Date: August 1993
Creator: Meyer, Rhonda D. (Rhonda Dawn)
Partner: UNT Libraries

The effects of structured approaches to computer implementation in small businesses: a study of the relationships between level of systematic approach and implementation time, implementation cost, user satisfaction and level of integration

Description: The purpose of this research is to determine the effects of systematic approach to computer integration on implementation cost, implementation time, user satisfaction, and level of integration in small business environments. It is believed that decreased costs and implementation time result from the use of systematic approaches to computer integration. Systematic approaches may also result in higher user satisfaction and a higher level of system integration.
Date: May 1991
Creator: Savoie, Michael J.
Partner: UNT Libraries