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Slogans and Opposition Political Culture: Online Discourse in Iran's Green Movement
In this study I investigate the Iranian Green Movement supporters' use of slogans as political discourse on the Persian-language opposition website www.kaleme.com. Data was collected from the website's Kaleme section in the form of 22 articles and 3,500 user comments. A coding scheme was constructed to measure the presence of categories and themes in the site's comments section. Findings support the propositions of narrative theorists (e.g. Franzosi, 1998; Benford, 1993) that frequent use of slogans in the comments may reflect a unique cultural element of Persian-language political discourse and reinforce the Green Movement's narrative of opposition to the government.
Date:
December 2012
Creator:
Ryan, Trent
System:
The UNT Digital Library
Solid Lubrication Mechanisms in Laser Deposited Nickel-titanium-carbon Metal Matrix Composites
A Ni/TiC/C metal matrix composite (MMC) has been processed using the laser engineered net shaping (LENS) process from commercially available powders with a Ni-3Ti-20C (atomic %) composition. This processing route produces the in-situ formation of homogeneously distributed eutectic and primary titanium carbide and graphite precipitates throughout the Ni matrix. The composite exhibits promising tribological properties when tested in dry sliding conditions with a low steady state coefficient of friction (CoF) of ~0.1 and lower wear rates in comparison to LENS deposited pure Ni. The as deposited and tribologically worn composite has been characterized using Auger electron spectroscopy, scanning electron microscopy (SEM), X-ray diffraction, high resolution transmission electron microscopy (HRTEM) with energy dispersive spectroscopy (EDS), dual beam focused ion beam SEM (FIB/SEM) serial sectioning and Vickers micro-hardness testing. The evolution of subsurface stress states and precipitate motion during repeated sliding contact has been investigated using finite element analysis (FEA). The results of FIB/SEM serial sectioning, HRTEM, and Auger electron spectroscopy in conjunction with FEA simulations reveal that the improved tribological behavior is due to the in-situ formation of a low interfacial shear strength amorphous carbon tribofilm that is extruded to the surface via refined Ni grain boundaries.
Date:
December 2012
Creator:
Mogonye, Jon-Erik
System:
The UNT Digital Library
Somatostatin Receptors on Neuronal Cilia: Evidence for Neuroprotection
Primary cilia are essential in brain development, as mediators of sonic hedgehog signaling. However, their role in mature neurons remains elusive. One means to elucidate their function may be to investigate the function of the somatostatin type 3 receptor (SstR3), which is concentrated on the primary cilia of neurons. The inhibitory and anticonvulsant properties of somatostatin suggest that ciliary SstR3 might protect neurons against excitotoxicity, as seen in epileptic seizures. C57BL/6 wild type (wt) and SstR3 knockout mice were administered vehicle or epileptogenic agents kainic acid (KA) or pentylenetetrazole. Seizure behaviors were rated on seizure severity scales. KA-induced seizure behaviors were more severe in SstR3 mutants than in wt. Correspondingly, the mutants showed greater reactive gliosis, as indicated by increased numbers of GFAP immunoreactive (GFAP(+)) astrocyte processes. In addition, seizure severity was associated with a greater percentage of neural stem cells having an ACIII(+) cilium. Following injections of pentylenetetrazole, SstR3 mutants reached maximum seizure levels faster than wt. These results support the hypothesis that ciliary SstR3 are neuroprotective in mature neurons, and may provide a new avenue for the treatment of seizures.
Date:
December 2012
Creator:
Evans, Shakila K.
System:
The UNT Digital Library
Source and Channel Coding Strategies for Wireless Sensor Networks
In this dissertation, I focus on source coding techniques as well as channel coding techniques. I addressed the challenges in WSN by developing (1) a new source coding strategy for erasure channels that has better distortion performance compared to MDC; (2) a new cooperative channel coding strategy for multiple access channels that has better channel outage performances compared to MIMO; (3) a new source-channel cooperation strategy to accomplish source-to-fusion center communication that reduces system distortion and improves outage performance. First, I draw a parallel between the 2x2 MDC scheme and the Alamouti's space time block coding (STBC) scheme and observe the commonality in their mathematical models. This commonality allows us to observe the duality between the two diversity techniques. Making use of this duality, I develop an MDC scheme with pairwise complex correlating transform. Theoretically, I show that MDC scheme results in: 1) complete elimination of the estimation error when only one descriptor is received; 2) greater efficiency in recovering the stronger descriptor (with larger variance) from the weaker descriptor; and 3) improved performance in terms of minimized distortion as the quantization error gets reduced. Experiments are also performed on real images to demonstrate these benefits. Second, I present a …
Date:
December 2012
Creator:
Li, Li
System:
The UNT Digital Library
Spatio-temporal Variation of Nitrate Levels in Groundwater in Texas, 1970 to 2010
This study looks at spatial variation of groundwater nitrate in Texas and its fluctuations at 10 year increments using data from the Texas Water Development Board. While groundwater nitrate increased in the Ogallala and Seymour aquifers across the time period, the overall rate in Texas appears to be declining as time progresses. However, the available data is limited. Findings show that a much more targeted, knowledge based strategy for sampling would not only reduce the cost of water quality analysis but also reduce the risk of error in these analyses by providing a more realistic picture of the spatial variation of problem contaminants, thereby giving decision-makers a clearer picture on how best to handle the reduction and elimination of problem contaminants.
Date:
December 2012
Creator:
Rice, Susan C.
System:
The UNT Digital Library
Staying Connected: Technology Use in Grandparent-grandchild Relationships
Despite the distance that often separates grandparents from their young adult grandchildren, the abundance of new technologies provides numerous means of connection for the grandparent-grandchild (GP-GC) dyad. The purpose of this study was to understand how grandparents use technology, namely text messaging and Facebook, in relationships with their young adult grandchildren. Specifically, the aim was to understand grandparents' purposes for using these technologies with their grandchildren, their motivations for using these technologies, and their perceptions of these technologies. Qualitative interviews were conducted with 23 grandparent participants and analyzed according to the procedures delineated in grounded theory analysis. Both text messaging and Facebook emerged as important tools for connection, as text messaging encourages more frequent communication and Facebook helps grandparents "fill in the gaps" about their grandchildren's lives. Furthermore, results indicated that grandparents' uses of text messaging, and to a lesser extent Facebook, are acts of accommodation to their grandchildren.
Date:
December 2012
Creator:
Novak, Hannah R.
System:
The UNT Digital Library
The Structural Determinants of Americans' Justice Perceptions Toward Inequality in the U.S.
In accordance with structural theory and distributive justice theory, this study investigates if Americans' personal encounters with the opportunity structure and their existing reward conditions will influence their perceptions toward distribution outcomes in the U.S. I argue that higher-status individuals possessing various "attributes of structural privilege" will exhibit less support for regulating income inequality in society than lower-status individuals. Upward mobility should also be negatively related to support for restoring greater equality in allocation outcomes. However, the effect of mobility on justice perceptions should vary by class status, since class has been known to be a reliable predictor of these attitudes. The study employed a sample of 438 American adults from the GSS 2000 dataset, and ordinary least squares (OLS) regression was applied in the analyses of the data. Two of the three above hypotheses received partial confirmation, that is, there were class, race, and gender differences in distributive justice perceptions. Class also interacted significantly with occupational mobility in altering distributive justice perceptions.
Date:
December 2012
Creator:
Ong, Corinne
System:
The UNT Digital Library
Student Facilitation and Predictors of Engagement in Peer-Led Literature Circle Discussions
The purpose of this research was to examine the relation between students' personality traits and the extent of their engagement and facilitation in peer-led literature circle discussions. The research was guided by two questions. To what extent do reading ability, gender, and personality traits predict the quality of verbal engagement in literature circles? and How do highly engaged participants facilitate discussion in the circles? The researcher video-taped 17 fourth-grade students' literature circle discussions for a total of 136.7 minutes collected on two separate occasions across two weeks. To answer the first question student contributions in discussions were quantified into a measure of quality of verbal engagement score (cf. Costa & Kallick, 2000). This quality of verbal engagement score served as the dependent variable in a multiple regression. The seven independent variables were (1) extroversion, (2) agreeableness, (3) conscientiousness, (4) emotional stability, (5) openness, (6) reading ability, and (7) gender. The quantitative analysis in this study revealed that emotional stability was the only significant variable that predicted higher quality of verbal engagement. A post hoc analysis that included group size as an additional variable revealed that groups composed of three members correlated with higher overall quality of verbal engagement. The second …
Date:
December 2012
Creator:
Young, Chase
System:
The UNT Digital Library
Students' Attitudes Towards Rapport-building Traits and Practices in Online Learning Environments
This research was a triangulated study of student attitudes towards instructors' rapport-building traits and their preferences amongst instructors' rapport-building practices in online learning environments. Participants were undergraduate and graduate students enrolled in courses within an educational technology program at a central Texas university. The study employed a mixed-methods approach involving the Likert-item assessment of learners' attitudes, the identification and prioritization of learner preferences through pairwise comparisons, and semi-structured interviews that provided richer, more detailed information. Findings indicated a strong preference for instructor-based traits and practices over pedagogically-based ones. These traits and practices loaded into the components of social presence, enjoyable interaction, and personal connection.
Date:
December 2012
Creator:
Wright, Robert Demmon
System:
The UNT Digital Library
Study of Novel Ion/surface Interactions Using Soft-landing Ion Mobility
Preparative mass spectrometry is a gas-phase ion deposition technique aimed at deposition of monodisperse ion beams on a surface. This is accomplished through the implementation of a soft-landing ion mobility system which allows for high ion flux of conformationally selected ion packets. The soft-landing ion mobility system has been applied to a number of unique chemical problems including the deposition of insulators on graphene, the preparation of reusable surface enhanced Raman spectroscopic substrates, and the deposition of uranium nanoparticles. Soft-landing ion mobility provided a platform for the quick deposition of usable amounts of materials, which is the major objective of preparative mass spectrometry. Soft-landing ion mobility is unique when compared to other preparative mass spectrometric techniques in that the ion packets are conformationally separated, not separated on mass to charge ratio. This provides orthogonal complementary data to traditional mass spectrometric techniques and allows for the study of conformationally monodisperse surfaces. The diversity of problems that have been and continued to be explored with soft-landing ion mobility highlight the utility of the technique as a novel tool for the study of multiple ion/surface interactions.
Date:
December 2012
Creator:
Hoffmann, William Darryle
System:
The UNT Digital Library
Sustainable Environmental Identities for Environmental Sustainability: Remaking Environmental Identities with the Help of Indigenous Knowledge
Early literature in the field of environmental ethics suggests that environmental problems are not technological problems requiring technological solutions, but rather are problems deeply rooted in Western value systems calling for a reorientation of our values. This dissertation examines what resources are available to us in reorienting our values if this starting point is correct. Three positions can be observed in the environmental ethics literature on this issue: 1. We can go back and reinterpret our Western canonical texts and figures to determine if they can be useful in providing fresh insight on today's environmental challenges; 2. We abandon the traditional approaches, since these are what led to the crisis in the first place, and we seek to establish entirely new approaches and new environmental identities to face the environmental challenges of the 21st century; 3. We look outside of the Western tradition for guidance from other cultures to see how they inhabit and interact with the natural world. This dissertation presents and evaluates these three options and ultimately argues for an approach similar to the third option, suggesting that dialogue with indigenous cultures and traditions can help us to reorient our values and assist in developing more sustainable environmental …
Date:
December 2012
Creator:
Parker, Jonathan
System:
The UNT Digital Library
Teacher Perception of Project-Based Learning in a Technology-infused Secondary School Culture: a Critical Ciné-ethnographic Study
Project-based learning has long been used in the educational realm as it emphasis a student-centered strategy which promotes meaning, enriched learning that enhances inquiry and problem-solving skills in a rich, authentic environment. The relevance and authentic design of projects may further be enhanced by the use of technology in the classroom. Technology is rapidly changing the face of American education in ways that were barely thinkable as little as five years before and provides the possibility for student to collaborate and complete complex project-based tasks with further level of authenticity which connects to the students preferred method of learning and productivity outside the classroom. At New Tech high school in Coppell, Texas, the entire curriculum is based around this project-based learning in a technology-infused classroom. This qualitative, case-based study is designed to explore and examine the teachers' perceptions of the use of project-based learning, technology in this non-traditional environment. The study also investigates the teacher perceptions of students' response to project-based learning and the technology available to them in their project-based tasks. Finally the study discusses the finding and their possible implications for traditional educational environments.
Date:
December 2012
Creator:
Gratch, Jonathan
System:
The UNT Digital Library
Theoretical and Experimental Investigations of Peg Based Thermo Sensitive Hydro Microgel
Poly ethylene glycol (PEG) based microgels were synthesized and investigated. The PEG microgel has the same phase transition as the traditional poly N-isopropylacrylamide (PNIPAM). As a good substitute of PNIPAM, PEG microgel exhibits many advantages: it is easier to control the lower critical solution temperature (LCST) of the microgel by changing the component of copolymers; it has a more solid spherical core-shell structure to have a double thermo sensitivity; it is straightforward to add other sensitivities such as pH, magnetic field or organic functional groups; it readily forms a photonic crystal structure exhibiting Bragg diffraction; and, most importantly, the PEG microgel is biocompatible with human body and has been approved by FDA while PNIPAM has not. PEG microgels with core-shell structure are synthesized with a two-step free radical polymerization and characterized with DLS, SLS and UV–Vis. The dynamic mechanics of melting and recrystallizing of the PEG core-shell microgel are presented and discussed. Photonic crystals of PEG microgels were synthesized and characterized. The crystal can be isolated in a thin film or a bulk column. The phase transition of PEG microgel was simulated with the mean field theory. The enthalpy and entropy of phase transition can be estimated from the best …
Date:
December 2012
Creator:
Chi, Chenglin
System:
The UNT Digital Library
Thermochemistry Investigations Via the Correlation Consistent Composite Approach
Since the development of the correlation consistent composite approach (ccCA) in 2006, ccCA has been shown to be applicable across the periodic table, producing, on average, energetic properties (e.g., ionization potentials, electron affinities, enthalpies of formation, bond dissociation energies) within 1 kcal/mol for main group compounds. This dissertation utilizes ccCA in the investigation of several chemical systems including nitrogen-containing compounds, sulfur-containing compounds, and carbon dioxide complexes. The prediction and calculation of energetic properties (e.g., enthalpies of formation and interaction energies) of the chemical systems investigated within this dissertation has led to suggestions of novel insensitive highly energetic nitrogen-containing compounds, defined reaction mechanisms for sulfur compounds allowing for increased accuracy compared to experimental enthalpies of formation, and a quantitative structure activity relationship for altering the affinity of CO2 with substituted amine compounds. Additionally, a study is presented on the convergence of correlation energy and optimal domain criteria for local Møller–Plesset theory (LMP2).
Date:
December 2012
Creator:
Jorgensen, Kameron R.
System:
The UNT Digital Library
The Use of Conjugate Reinforcement in Autism Treatment Programs: a Demonstration and Discussion
The effect of a reinforcer on behavior is largely determined by the schedule in which it is implemented. One type of reinforcement schedule that has not been explored extensively is conjugate reinforcement. Previous researchers have used conjugate schedules to evaluate a reinforcer's effects on behavior and as an assessment tool. However, none have explored how to effectively engineer conjugate schedules in applied settings. The current study explores the effectiveness of conjugate reinforcement implemented by several interventionists across a variety of responses, reinforcers, and in a wide range of participants with autism. The results indicated that delivering social, audio/visual, and tangible stimuli in a conjugate schedule resulted in increased durations of various target responses (e.g. social skills, motor skills) and non-targeted measures (e.g., approach, social bids, speed) across participants. Considerations regarding reinforcer and response selection in implementing conjugate schedules in applied settings are provided.
Date:
December 2012
Creator:
Reetz, Stephany Kristina
System:
The UNT Digital Library
Variations in Suicidal Ideation Among Substance Users
Research suggests that substance use is a risk factor for increased suicidal ideation. This study explored the relationship between substance use, suicidal ideation, and impulsivity in a sample of college students and individuals seeking outpatient treatment. Participants were interviewed for information on severity of suicidal ideation and substance use. Participants completed the Psychiatric Diagnostic Screening Questionnaire, the substance use section of the Structured Clinical Interview for the DSM-IV, the Alcohol Use Disorders Identification Test, the Scale for Suicide Ideation, and the UPPS-P Impulsivity Behavior Scale. These measures were used to determine the amount of variance in suicidal ideation accounted for by substance use. Variables reflecting substance use classification, frequency, and severity were used to predict severity of suicidal ideation.
Date:
December 2012
Creator:
Nichols, Erica
System:
The UNT Digital Library
Water-soluble Phosphors for Hypoxia Detection in Chemical and Biological Media
Water-soluble Pt(II) phosphors exist predominantly for photophysical studies. However, fewer are known to be candidates for cisplatin derivatives. If such a molecule could exist, it would be efficient at not only destroying the cancerous cells which harm the body, but the destruction would also be traceable within the human body as it occurred. Herein, research accomplished in chemistry describes the photophysical properties of a water-soluble phosphor. Spectroscopically, this phosphor is unique in that it possesses a strong green emission at room temperature in aqueous media. Its emission is also sensitive to the gaseous environment. These properties have been expanded to both analytical and biological applications. Studies showing the potential use of the phosphor as a heavy metal remover from aqueous solutions have been accomplished. The removal of toxic heavy metals was indicated by the loss of emission as well as the appearance of a precipitate. The gaseous sensitivity was elicited to be used as a potential cancerous cell biomarker. In vivo studies were accomplished in a wide variety of species, including bacteria (E. coli), worms (C. elegans), small crustaceans (Artemia), and fish (D. rerio and S. ocellatus). The phosphor in question is detectable in all of the above. This fundamental …
Date:
December 2012
Creator:
Satumtira, Nisa Tara
System:
The UNT Digital Library
Zero Anaphora and Meithei
The focus of this thesis is to determine what factors predict zero anaphora in Meithei. The data for this thesis is derived from pear stories. Arguments were tabulated in spreadsheets counting nouns, pronouns, and zero anaphors; they were also examined for their semantic role and information status. The findings showed the agent role was typically represented by reduced forms of reference, the majority of the time by zero anaphora. Other semantic roles were typically represented by lexical full forms of reference. Agents were strongly correlated to previous subjects. Other semantic roles were typically found in the other information status categories. The conclusion drawn from these findings is semantic role and information status influence accessibility, and accessibility determines whether or not arguments are represented by zero anaphors in Meithei.
Date:
December 2012
Creator:
Cockerham, Terence
System:
The UNT Digital Library