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Attention and Metacognition in the Elaborated Intrusion Theory of Desire

Description: The elaborated intrusion (EI) theory of desire is a cognitive model that describes the processes involved in craving as intrusive thoughts that are elaborated upon leading to dissonance when desires are not met. While the theory is based on a wide body of research, certain theoretical predictions have not been fully examined. Specifically, EI theory argues that mental imagery has a central role in craving, and predicts that attempts to suppress substance-related intrusive thoughts and mental imagery is related to increased craving. Further, EI theory suggests that elaboration of craving imagery is related to attention and working memory processes, however, there are questions about whether differential performance in these domains is related to craving. The current study examined the relationship between attention/working memory performance and alcohol craving in a sample of 119 young adult males. Additionally, metacognition was examined to clarify the phenomenological aspects of craving within EI theory. Attention and working memory performance did not significantly predict intrusive thought and mental imagery elaboration. Individuals with high craving reported significantly higher levels of anxiety, thought suppression, and greater strength and frequency of craving-related mental imagery. They were also more likely to try to control their own thoughts and make negative judgments on their ability to do so. The strength of craving-related intrusive thoughts, not mental imagery, was the most significant predictor of craving. Implications for the understanding of craving and treatment recommendations based on the findings are discussed.
Date: August 2013
Creator: Yates III, Robert D.
Partner: UNT Libraries

From Germany to Palestine: a Comparison of Two Choral Works by Paul Ben-haim – “Joram” and “Kabbalat Shabbat”

Description: The choral music of Israeli composer Paul Ben-Haim (1897-1984) falls clearly into two distinct compositional periods. Born in Munich, Germany as Paul Frankenburger, the composer received formal, classical training at the Munich Academy of Music. His compositions from this period are an amalgamation of many styles, and they include influences of Bach, Handel, Mahler, Debussy, and Strauss. In 1933, Ben-Haim, along with other trained artists and composers, immigrated to Palestine as part of the Fifth Aliyah. Prior to this wave of immigration, Palestine had not yet received any serious composers, and musically, was still in its infancy. Eager to divorce themselves from the West and identify with their new home in the East, Ben-Haim and his fellow transplant composers sought a new musical language and a unique voice for Israel. Enamored with the exotic sounds of his new environment, Ben-Haim began to absorb elements of Eastern Mediterranean music into his compositions. As a Westerner, he was not familiar with these Eastern traditional folk song melodies, modes, and scales, and he required outside source materials from which to draw. This document examines two choral works, one from each of Paul Ben-Haim’s style periods, Joram (1933) and Kabbalat Shabbat (1968), and identifies the compositional source materials that yielded a significant change in the character and style of his work.
Date: August 2013
Creator: Dalrymple, Holly
Partner: UNT Libraries

Social Media in Policing: a Study of Dallas-fort Worth Area City Police Departments

Description: Social media offers numerous opportunities to companies, organizations and government agencies to communicate with people outside their organization, to promote their interests and to better serve their customers, or as in the case with government agencies, to better serve their citizens. However, little is known about how police departments in particular use social media. This research study explores why police departments use social media, how they manage their social media tools, and the problems and challenges experienced as they use social media. This qualitative study is largely guided by grounded theory. The data were collected from a study population using local police departments in the Dallas-Fort worth (DFW) area principal cities using both individual interviews with police departments’ social media officers and observations of these departments’ online social media tools (in particular, Facebook and Twitter). This study has shown that the DFW area city police departments are using social media quite extensively to keep the public informed and often for investigative purposes. There are some success factors to adopting and using these tools, such as the motivation of department staff and their benefits, successful implementation of the tools, the simplicity of using tools and that it is absolutely free.
Date: August 2013
Creator: Altunbas, Fuat
Partner: UNT Libraries

Comparison of Learning Performance Between Students Who Do and Students Who Do Not Use Mobile Technology-based Activities

Description: This study examined if using mobile technology-based activities would increase student performance in biological science courses. The study compared two groups of students in lectures and labs. Each group had about 20 students. The mobile group had mobile technology-based activities and the non-mobile group received conventional instruction. The mobile group used links to the website, or a QR Code to access the activities. The non-mobile group had handouts and worksheets over the same content. The research methodology for this study was mixed method. The study was a quasi-experimental design that used instruction method as the independent variable between two groups. The study used formative and summative assessment to compare the performance of the mobile group and non-mobile group in lecture and lab. The student in the mobile group had statistically significantly higher lab exam scores than students in the non-mobile group. Additionally, Students were surveyed about their performance expectancy and effort expectancy using mobile technology for learning, and they were asked about their self-management of learning. Analysis indicated that both groups had similar performance and effort expectancy using mobile technology for learning, but the two groups differed on self-management of learning responses to the survey. Focus groups from the mobile group and the non-mobile group were interviewed about issues related to benefits and challenges encountered learning with mobile technology-based activities.
Date: August 2013
Creator: Stowe Jr., William A.
Partner: UNT Libraries

Using Baroque Vocal Music to Introduce Horn Students to the Musical Concepts of Expression, Articulation, Phrasing, and Tempo

Description: Baroque music is an area largely neglected in the music education of young horn students and wind players in general. Baroque horn repertoire is very demanding primarily due to the range. Baroque composers wrote for horn using the uppermost register of the instrument. In this range the partials are closer together, allowing for more melodic writing. This music requires an advanced level of technique, endurance, and ability. Often this repertoire is not suitable for students until they are well into their collegiate years of study. Frequently this music is performed on descant horns. Since only a small number of middle school and high school horn students continue to play after they leave their school band programs, they many never get first hand experience performing Baroque music. Vocal students are often introduced to Baroque arias early in their training. Purcell’s songs and arias are an excellent example of the literature that young voice students use. These arias and songs can be the perfect portal to Baroque music for horn students as well. Here I have created an edition of Henry Purcell’s songs and arias for young horn students. Each aria used the text as a guide for the “affect” and its impact on tone, articulation, and phrasing. The bass line is also used as a guide for determining tempo and style. Each piece is transcribed as a solo with piano accompaniment and as a duet. The goal of this edition is to use Baroque vocal music to introduce horn students to the musical concepts of expression, articulation, phrasing, and tempo.
Date: May 2014
Creator: Winter, Angela K.
Partner: UNT Libraries

Technology-enhanced Classroom Environments and English Language Acquisition Among Native Spanish-speaking, English Language Learners in the Preschool and Elementary Classroom

Description: This qualitative study addressed the question: What are the perceptions of preschool and elementary bilingual and ESL teachers on how technology-enhanced classroom environments support native Spanish-speaking English language learners in the acquisition of English as a second language? With the support of six school districts representing three different regions and 15 schools in Texas, this research investigated technology-enhanced learning environments and the influence of emerging technologies on language acquisition by focusing on classroom interactions and learner engagement in preschool and elementary settings. Forty-six teachers completed the self-identified online questionnaire and from that initial group of participants, 10 were chosen for the face-to-face semi-structured interviews. A two-cycle progressive refinement coding technique was used for the analysis of the teacher interviews. In Vivo coding was selected for the first-cycle coding methodology to study teacher perspectives using their direct language. For the second-cycle methodology, focus coding was chosen as a continuation of the analytical process examining the developing patterns resulting in the initial codes being grouped to form salient categories. This process of reanalyzing and reorganizing coded data led to the creation of four emergent themes and in the views of the teachers interviewed describes how emerging technologies influences English language acquisition. The four emergent themes identified were “engaging students for learning,” collaborating with others,” “developing and clarifying concepts,” and “creating authentic work.”
Date: August 2013
Creator: Miller, Gary
Partner: UNT Libraries

User Acceptance of Technology: an Empirical Examination of Factors Leading to Adoption of Decision Support Technologies for Emergency Management

Description: This study examines factors that influence the intent to use and actual use of decision support software (DSS) technology by emergency management officials to facilitate disaster response management. The unified theory of acceptance and use of technology popularized by scholars from the field of information sciences (IS) for the private sector is adapted and extended to examine technology use in the public sector, specifically by emergency managers. An e-survey was sent to 1, 452 city and county emergency management officials from FEMA region VI and complete responses obtained from 194 were analyzed. Findings suggest that social influence is the strongest predictor of intent to use DSS technology by emergency managers, unlike private sector studies where performance expectancy was the strongest predictor. Additionally, effort expectancy, collaboration, social vulnerability, professionalism, performance expectancy, and gender explained 40 percent of their intent to use DSS technology. Factors explaining actual use of technology were intent to use technology, having an in house GIS specialist, and age of the emergency manager. This research successfully closes the gap in IS and disaster literature by being the first to focus on factors influencing technology use by emergency managers for decision making in disaster response. It underscores the importance of collaboration not only for post-disaster activities but also as a precursor to better disaster preparedness planning that calls for information sharing and technology acceptance and adoption across partnering jurisdictions.
Date: August 2013
Creator: Jennings, Eliot A.
Partner: UNT Libraries

Thematic and Formal Narrative in Respighi’s Sinfonia Drammatica

Description: Respighi’s scarcely-known orchestral work Sinfonia Drammatica lives up to its title by evoking a narrative throughout the course of its three movements. In this dissertation, I argue how the work’s surface, subsurface, and formal elements suggest this narrative which emerges as a cycle of rising and falling dramatic tension. I explain how Respighi constructs the work’s narrative in the musical surface through a diverse body of themes that employ three motives of contour. The disposition and manipulation of these motives within the themes suggest frequent fluctuations of the level of conflict throughout the symphony as a whole. To show the involvement of musical forms in the work’s narrative, I employ an approach which integrates harmony and thematic behavior. I utilize analytical methods from the current Formenlehre, including terms from James Hepokoski and Warren Darcy’s sonata deformation theory and William Caplin’s theories of formal functions to elucidate ties between the forms of the Sinfonia Drammatica’s movements and those of conventional sonata forms of the late-eighteenth century. This dissertation also employs Heinrich Schenker’s theories of structures, voice leading, and reduction to illustrate large-scale aspects of the Sinfonia Drammatica’s narrative. The resulting analyses show Respighi’s elaborations of common structural paradigms which serve to heighten the articulation of the narrative.
Date: May 2014
Creator: Amato, Alexander G.
Partner: UNT Libraries

The Changing Symbolic Images of the Trumpet: Bologna and Venice in the Seventeenth Century

Description: The trumpet is among the most ancient of all musical instruments, and an examination of its history reveals that it has consistently maintained important and specific symbolic roles in society. Although from its origins this symbolic identity was linked to the instrument’s limited ceremonial and signaling function, the seventeenth century represents a period in which a variety of new roles and identities emerged. Bologna and Venice represent the two most important centers for trumpet writing in Italy during the seventeenth century. Because of the differing ideologies at work in these cities, two distinctive symbolic images of the instrument and two different ways of writing for it emerged. The trumpet’s ecclesiastic role in Bologna and its participation in Venetian opera put the instrument at the service of two societies, one centered around the Church, and another around a more permissive state. Against the backdrop of the social and political structures in Venice and Bologna, and through an examination of its newly-emerging musical roles in each city, the trumpet’s changing identities during a most important point in the history of the instrument will be examined.
Date: May 2014
Creator: Karp, Jamie Marie
Partner: UNT Libraries

The Poetic and Musical Dialogue of Ambrosini and Cavalcanti: a Study of Claudio Ambrosini’s a Guisa Di Un Arcier Presto Soriano for Solo Flute

Description: Claudio Ambrosini’s (b. 1948) unpublished work for unaccompanied flute, A guisa di un arcier presto soriano (1981), although virtually unknown to the musical public and to connoisseurs alike, represents one of the most dazzling and impressive displays of extended techniques in the repertoire of solo flute music. The title, A guisa di un arcier presto soriano, comes from the seventh line of a sonnet by the Italian medieval poet Guido Cavalcanti (ca. 1250-1300) and translates as “just like a fast Syrian archer.” The archer in question is Eros, the Greek god of love. By the composer’s own admission, the form and expression of this piece is closely linked with the form and expression of Cavalcanti’s sonnet. In particular, Ambrosini intimates three elements specifically drawn from the poem: 1) moments of tension and suspense, as Eros silently approaches his target with bow and arrow in hand; 2) moments of love, even to the point of suggesting a love song; and 3) moments that suggest the fast passage of arrows. The purpose of this dissertation is to explore these three elements in Ambrosini’s work and to trace the correlations of the same elements in Cavalcanti’s sonnet. The expression of such concrete poetic imagery in Ambrosini’s music is at times easily deciphered through clear programmatic gestures or wordless madrigalisms; and at other times the symbolism of the poetry is developed in a hidden and metaphorical manner in its musical iteration. Further, Ambrosini’s use of a particularly colorful and vast array of extended techniques serves as the impetus for the formal structure that the music embodies, and I will show that this formal structure is itself a symbolic and metaphorical representation of the poetic significance of Cavalcanti’s sonnet.
Date: August 2013
Creator: Choi, Su-hyun
Partner: UNT Libraries

Engaging Lives: a Nomadic Inquiry Into the Spatial Assemblages and Ethico-aesthetic Practices of Three Makers

Description: This research is a nomadic inquiry into the ethics and aesthetics of three makers’ social and material practices. Deleuze’s concept of the nomad operated in multiple ways throughout the process, which was embedded in performative engagements that produced narratives of becoming. Over four months, I built relationships with three people as I learned about the ethico-aesthetic significance of their daily practices. The process started by interviewing participants in their homes and expanded over time to formal and informal engagements in school, community, and agricultural settings. I used Guattari’s ecosophical approach to consider how subjectivity was produced through spatial assemblages by spending time with participants, discussing material structures and objects, listening to personal histories, and collaboratively developing ideas. Participants included a builder who repurposed a missile base into a private residence and community gathering space, an elementary art teacher who practiced urban homesteading, and a young artist who developed an educational farm. The research considers the affective force of normalized social values, the production of desire by designer capitalism, and the mutation of life from neoliberal policies. Our experiences illuminate the community-building potential of direct encounters and direct exchanges. The project generates ideas for becoming an inquirer in the everyday and reveals possibilities for producing pedagogical experiences through collective and dissensual action. Ultimately, the project produces hope for performative and anti-disciplinary approaches to education, rupturing false divisions that fragment the force of thought, to produce, instead, aesthetic experiences that privilege processes and are based in direct and collective engagements with life.
Date: May 2014
Creator: Coats, Cala R.
Partner: UNT Libraries

An Analysis of Honegger’s Cello Concerto (1929): a Return to Simplicity?

Description: Literature available on Honegger’s Cello Concerto suggests this concerto is often considered as a composition that resonates with Les Six traditions. While reflecting currents of Les Six, the Cello Concerto also features departures from Erik Satie’s and Jean Cocteau’s ideal for French composers to return to simplicity. Both characteristics of and departures from Les Six examined in this concerto include metric organization, thematic and rhythmic development, melodic wedge shapes, contrapuntal techniques, simplicity in orchestration, diatonicism, the use of humor, jazz influences, and other unique performance techniques.
Date: May 2014
Creator: Kleinmann, Denika Lam
Partner: UNT Libraries

Showing the Flag: War Cruiser Karlsruhe and Germandom Abroad

Description: In the early 1920s the Weimar Republic commissioned a series of new light cruisers of the Königsberg class and in July 1926, the keel of the later christened Karlsruhe was laid down. The 570 feet long and almost 50 feet wide ship was used as a training cruiser for future German naval officers. Between 1930 and 1936 the ship conducted in all five good-will tours around the world, two under the Weimar Republic and three under the Third Reich. These good-will tours or gute Willen Fahrten were an important first step in reconciling Germany to the rest of the world and were meant to improve international relations. The Foreign Office and the Ministry of Defense carefully orchestrated all stops of the vessels in conjunction with the respective embassies abroad. Final arrangements were made at least six-nine months before the scheduled visits and even small adjustments to the itinerary proved troublesome. Further, all visits were treated as “unofficial presentations.” The mission of the Karlsruhe was twofold: first to extend or renew relations with other nations, and second to foster notions of Heimat and the Germandom (Deutschtum) abroad. The dissertation is divided in two large parts; the individual training cruises with all the arrangements, the selection of the individual nations and ports, and explores the level of decision making amongst the various agencies, departments, and organizations involved. For the Weimar Republic, the ship represented modernity and a break with the past, and embodied at one and the same time, traditional German culture and the idea of progress. Since the cruiser continued its training abroad after 1933, a comparison between the “two Germanies” makes sense. The second part of the research will explore the notion of Heimat and the Germans living abroad and how the Karlsruhe acted as a symbolic link between the ...
Date: August 2013
Creator: De Santiago Ramos, Simone Carlota Cezanne
Partner: UNT Libraries

Si Se Puede: an Investigation of Factors Fostering Allied Health Graduate Degree Completion for Latinos/as

Description: This study uncovers the experiences of Latinos/as in allied health graduate programs and provides vital information which may help increase the number of Latino/a healthcare providers. It focuses on the testimonios (life narratives) of 9 Latinos/as who graduated from allied health graduate programs. Academic resilience and community cultural wealth theories framed the study while testimonio methodology guided data collection. Alumni were interviewed about the personal experiences and educational journeys that led them to successfully complete graduate allied health degrees. Participants’ family background, educational history, personal and environmental factors were considered. Participants described learning about the value of education early in their lives in home and school settings. The interviews also revealed the importance of participants’ personal drive and desire to excel academically and professionally. Participants noted that the academic rigor and adjustment required to succeed in graduate allied health programs, combined with feelings of social isolation, made their transition to the graduate program challenging. Family and social networks were noted as the most supportive in regards to participants’ retention and success. Research implications include the use of methodologies and theoretical frameworks which focus on the voices and experiences of underrepresented students in the allied health professions. Implications for allied health schools include intentional recruitment of underrepresented student populations, the establishment of social support systems, student affairs offices, and the inclusion of social class, ethnicity, and cultural diversity as standards by which allied health schools are rated for accreditation and re-accreditation purposes.
Date: August 2013
Creator: Olivares-Urueta, Mayra
Partner: UNT Libraries

Erich Wolfgang Korngold’s Idea of the “Modern”: Developing Variation in the Piano Concerto in C Sharp, Opus 17

Description: This study examines the Piano Concerto in C sharp, Op.17 (1923), by Erich Wolfgang Korngold (1897-1957), in light of developing variation, techniques that transform motivic ideas and create musical continuity in this work. The troublesome reception history of Korngold’s piano concerto derives from its complex musical features, which have created difficulties in understanding and evaluating this piece. Consequently, critics and scholars often label the highly sophisticated yet tonal musical language in this piece a residue of Romanticism from the nineteenth century. In this document, in contrast, examination of motivic development and connections in Korngold’s piano concerto reveals thematic and structural coherence in light of Korngold’s idea of modernity. This study provides a historical and technical survey of developing variation and discusses Korngold’s implementation of these techniques in his early compositions and the piano concerto. By doing so, this study recognizes the progressive aspect in Korngold’s music.
Date: May 2014
Creator: Huang, Shu-Yuan
Partner: UNT Libraries

Targeted and Metal-loaded Polymeric Nanoparticles As Potential Cancer Therapeutics

Description: Polymeric nanoparticles were designed, synthesized, and loaded with metal ions to explore the therapeutic potential for transition metals other than platinum found in cisplatin. Nanoparticles were synthesized to show the potential for polymer based vectors. Metal loading and release were characterized via Inductively Coupled Plasma Mass Spectrometry (ICP MS), Energy Dispersive X-Ray Spectroscopy (EDX), X-Ray Photoelectron Spectroscopy (XPS), and Elemental Analysis. Targeting was attempted with the expectation of observed increased particle uptake by cancer cells with flow cytometry and fluorescence microscopy. Results demonstrated that a variety of metals could be loaded to the nano-sized carriers in an aqueous environment, and that the release was pH-dependent. Expected increased targeting was inconsistent. The toxicity of these particles was measured in cancer cells where significant toxicity was observed in vitro via dosing of high copper-loaded nanoparticles and slight toxicity was observed in ruthenium-loaded nanoparticles. No significant toxicity was observed in cells dosed with metal-free nanoparticles. Future research will focus on ruthenium loaded polymeric nanoparticles with different targeting ligands dosed to different cell lines for the aim of increased uptake and decreased cancer cell viability.
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Date: May 2014
Creator: Harris, Alesha N.
Partner: UNT Libraries

The Mechanisms of Methane C–H Activation and Oxy-insertion Via Small Transition Metal Complexes: a DFT Computational Investigation

Description: Our country continues to demand clean renewable energy to meet the growing energy needs of our time. Thus, natural gas, which is 87% by volume of methane, has become a hot topic of discussion because it is a clean burning fuel. However, the transportation of methane is not easy because it is a gas at standard temperature and pressure. The usage of transition metals for the conversion of small organic species like methane into a liquid has been a longstanding practice in stoichiometric chemistry. Nonetheless, the current two-step process takes place at a high temperature and pressure for the conversion of methane and steam to methanol via CO + H2 (syngas). The direct oxidation of methane (CH4) into methanol (CH3OH) via homogeneous catalysis is of interest if the system can operate at standard pressure and a temperature less than 250 C. Methane is an inert gas due to the high C-H bond dissociation energy (BDE) of 105 kcal/mol. This dissertation discusses a series of computational investigations of oxy-insertion pathways to understand the essential chemistry behind the functionalization of methane via the use of homogeneous transition metal catalysis. The methane to methanol (MTM) catalytic cycle is made up of two key steps: (1) C-H activation by a metal-methoxy complex, (2) the insertion of oxygen into the metal−methyl bond (oxy-insertion). While, the first step (C-H activation) has been well studied, the second step has been less studied. Thus, this dissertation focuses on oxy-insertion via a two-step mechanism, oxygen-atom transfer (OAT) and methyl migration, utilizing transition metal complexes known to activate small organic species (e.g., PtII and PdII complexes). This research seeks to guide experimental investigations, and probe the role that metal charge and coordination number play.
Date: May 2014
Creator: Prince, Bruce M.
Partner: UNT Libraries

The Effects of Glyphosate Based Herbicides on Chick Embryo Development

Description: Glyphosate based herbicides are among the most widely used herbicides in the world. The purpose of this study was to determine developmental toxicity of glyphosate, the active ingredient in the common herbicide Roundup, on developing chicken embryos. Few studies have examined toxic effects of glyphosate alone versus the full compound formulations of Roundup, which include adjuvants and surfactants. Adjutants and surfactants are added to aid in solubility and absorption of glyphosate. In this study chicken embryos were exposed at the air cell on embryonic day 6 to 19.8 or 9.9 mg / Kg egg mass of glyphosate in Roundup or glyphosate only. Chickens treated with 19.8 and 9.9 mg / Kg glyphosate in Roundup showed significant reduction in survivability compared to glyphosate alone treatments and controls. On embryonic day 18, embryos were sacrificed for evaluation of developmental toxicity using wet embryo mass, dry embryo mass, and yolk mass as indicators. Morphology measurements were taken on liver mass, heart mass, tibiotarsus length and beak length. Embryos treated with 19.8 mg / Kg glyphosate and 9.9 mg / Kg glyphosate in Roundup showed significant reductions in wet and dry embryo mass and yolk mass. Tibiotarsus length in 9.9 mg / Kg glyphosate in Roundup treatments were significantly reduced compared to 9.9 mg / Kg glyphosate treatments. Beak length was significantly reduced in 9.9 mg /Kg glyphosate in Roundup treatments compared to all other groups.
Date: August 2013
Creator: Winnick, Blake Edward
Partner: UNT Libraries

Effects of Natural/anthropogenic Stressors and a Chemical Contaminant on Pre and Post Mycorrhizal Colonization in Wetland Plants

Description: Arbuscular mycorrhizal fungi, colonizing over 80% of all plants, were long thought absent in wetlands; however, recent studies have shown many wetland plants harbor arbuscular mycorrhizae (AM) and dark septate endophytes (DSE). Wetland services such as biodiversity, shoreline stabilization, water purification, flood control, etc. have been estimated to have a global value of $14.9 trillion. Recognition of these vital services is accompanied by growing concern for their vulnerability and continued loss, which has resulted in an increased need to understand wetland plant communities and mycorrhizal symbiosis. Factors regulating AM and DSE colonization need to be better understood to predict plant community response and ultimately wetland functioning when confronting natural and human induced stressors. This study focused on the effects of water quality, hydrology, sedimentation, and hurricanes on AM and DSE colonization in three wetland species (Taxodium distichum, Panicum hemitomon, and Typhal domingensis) and plant communities of coastal wetlands in Southeast Louisiana and effects of an antimicrobial biocide, triclosan (TCS), on AM (Glomus intraradices) spore germination, hyphal growth, hyphal branching, and colonization in fresh water wetland plants (Eclipta prostrata, Hibiscus laevis, and Sesbania herbacea) from bottom land hardwood forest in north central Texas. The former, mesocosm studies simulating coastal marsh vegetation ran for five years. In the latter studies, AM spores and wetland plants were exposed to 0 g/L, 0.4 g/L, and 4.0 g/L TCS concentrations in static renewal and flow through exposures for 21 and 30 days, respectively. AM and DSE colonization was significantly affected by individual and interactions of four independent variables in mesocosm experiments. Similarly, spore germination, hyphal growth, hyphal branching, and AM colonization in selected wetland plants were significantly lowered by exposure to the TCS at environmentally relevant concentrations. However, levels of effects were plant species and fungal propagules specific. My results showed that natural and human ...
Date: August 2013
Creator: Twanabasu, Bishnu Ram
Partner: UNT Libraries

Tissue-specific Bioconcentration Factor of the Synthetic Steroid Hormone Medroxyprogesterone Acetate (Mpa) in the Common Carp, Cyprinus Carpia

Description: Due to the wide spread occurrence of medroxyprogesterone acetate (MPA), a pharmaceutical compound, in wastewater effluent and surface waters, the objectives of this work were to determine the tissue specific uptake and bioconcentration factor (BCF) for MPA in common carp. BCFs were experimentally determined for MPA in fish using a 14-day laboratory test whereby carp where exposed to 100 μg/L of MPA for a 7-day period followed by a depuration phase in which fish were maintained in dechlorinated tap water for an additional 7 days. MPA concentrations in muscle, brain, liver and plasma were determined by liquid chromatography/mass spectrometry (LC/MS). The results from the experiment indicate that MPA can accumulate in fish, however, MPA is not considered to be bioaccumulative based on regulatory standards (BCF ≥ 1000). Although MPA has a low BCF value in common carp, this compound may cause reproductive effects in fish at environmentally relevant concentrations.
Date: August 2013
Creator: Steele IV, William B.
Partner: UNT Libraries

The Use of Social Media in Informal Scientific Communication Among Scholars: Modeling the Modern Invisible College

Description: The concept of the invisible college is a key focus of scientific communication research with many studies on this topic in the literature. However, while such studies have contributed to an understanding of the invisible college, they have not adequately explained the interaction of social and structural processes in this phenomenon. As a consequence, past research has described the invisible college differently based on researchers’ perspectives, resulting in misinterpretations or inconsistent definitions of the relevant social and structural processes. Information science and related disciplines have focused on the structural processes that lead to scholarly products or works while placing less emphasis on the social processes. To advance understanding of the invisible college and its dimensions (including both social processes and structural processes), a proposed model (Modern Invisible College Model, MICM) has been built based on the history of the invisible college and Lievrouw’s (1989) distinction between social and structural processes. The present study focuses on the social processes of informal communication between scholars via social media, rather than on the structural processes that lead to scholarly products or works. A developed survey and an employed quantitative research method were applied for data collection. The research population involved 77 scholars from the Institute of Public Administration (IPA), in Saudi Arabia. Descriptive statistics, frequency and percentage were conducted for each statement. Means and standard deviations were calculated. The results indicate that the majority of participants heavily use social media for scientific communication purposes. Also, the results confirm that scholars consider social media to be an effective and appropriate tool for scientific communication. Seven factors were found in the findings to have positive correlations with uses and gratifications theory and the use of social media. This research contributes to and benefits scholars, reference groups (i.e., the invisible college itself), and institutions, and provides ...
Date: May 2014
Creator: Algarni, Mohammed Ayedh
Partner: UNT Libraries

Novel Semi-Conductor Material Systems: Molecular Beam Epitaxial Growth and Characterization

Description: Semi-conductor industry relies heavily on silicon (Si). However, Si is not a direct-band gap semi-conductor. Consequently, Si does not possess great versatility for multi-functional applications in comparison with the direct band-gap III-V semi-conductors such as GaAs. To bridge this gap, what is ideally required is a semi-conductor material system that is based on silicon, but has significantly greater versatility. While sparsely studied, the semi-conducting silicides material systems offer great potential. Thus, I focused on the growth and structural characterization of ruthenium silicide and osmium silicide material systems. I also characterized iron silicon germanide films using extended x-ray absorption fine structure (EXAFS) to reveal phase, semi-conducting behavior, and to calculate nearest neighbor distances. The choice of these silicides material systems was due to their theoretically predicted and/or experimentally reported direct band gaps. However, the challenge was the existence of more than one stable phase/stoichiometric ratio of these materials. In order to possess the greatest control over the growth process, molecular beam epitaxy (MBE) has been employed. Structural and film quality comparisons of as-grown versus annealed films of ruthenium silicide are presented. Structural characterization and film quality of MBE grown ruthenium silicide and osmium silicide films via in situ and ex situ techniques have been done using reflection high energy electron diffraction, scanning tunneling microscopy, atomic force microscopy, cross-sectional scanning electron microscopy, x-ray photoelectron spectroscopy, and micro Raman spectroscopy. This is the first attempt, to the best of our knowledge, to grow osmium silicide thin films on Si(100) via the template method and compare it with the regular MBE growth method. The pros and cons of using the MBE template method for osmium silicide growth are discussed, as well as the structural differences of the as-grown versus annealed films. Future perspectives include further studies on other semi-conducting silicides material systems in terms ...
Date: December 2013
Creator: Elmarhoumi, Nader M.
Partner: UNT Libraries

3GPP Long Term Evolution LTE Scheduling

Description: Future generation cellular networks are expected to deliver an omnipresent broadband access network for an endlessly increasing number of subscribers. Long term Evolution (LTE) represents a significant milestone towards wireless networks known as 4G cellular networks. A key feature of LTE is the implementation of enhanced Radio Resource Management (RRM) mechanism to improve the system performance. The structure of LTE networks was simplified by diminishing the number of the nodes of the core network. Also, the design of the radio protocol architecture is quite unique. In order to achieve high data rate in LTE, 3rd Generation Partnership Project (3GPP) has selected Orthogonal Frequency Division Multiplexing (OFDM) as an appropriate scheme in terms of downlinks. However, the proper scheme for an uplink is the Single-Carrier Frequency Domain Multiple Access due to the peak-to-average-power-ratio (PAPR) constraint. LTE packet scheduling plays a primary role as part of RRM to improve the system’s data rate as well as supporting various QoS requirements of mobile services. The major function of the LTE packet scheduler is to assign Physical Resource Blocks (PRBs) to mobile User Equipment (UE). In our work, we formed a proposed packet scheduler algorithm. The proposed scheduler algorithm acts based on the number of UEs attached to the eNodeB. To evaluate the proposed scheduler algorithm, we assumed two different scenarios based on a number of UEs. When the number of UE is lower than the number of PRBs, the UEs with highest Channel Quality Indicator (CQI) will be assigned PRBs. Otherwise, the scheduler will assign PRBs based on a given proportional fairness metric. The eNodeB’s throughput is increased when the proposed algorithm was implemented.
Date: December 2013
Creator: Alotaibi, Sultan
Partner: UNT Libraries

Titanium Boride Formation and Its Subsequent Influence on Morphology and Crystallography of Alpha Precipitates in Titanium Alloys

Description: Over the last two decades there has been an increased interest in understanding the influence of trace boron additions in Ti alloys. These additions refine the prior β grain size in as-cast Ti alloys along with increasing their modulus and yield strength due to the precipitation of TiB. TiB also acts as a heterogeneous nucleation site for α precipitation and has been shown to influence the α phase morphology. B is completely soluble in liquid Ti but has a negligible solubility in both body centered cubic β and hexagonal close packed α phases of Ti. Thus, during solidification of hypoeutectic B containing alloys, B is rejected from β into the liquid where it reacts with Ti to form pristine single crystal whiskers of TiB. Despite a substantial amount of reported experimental work on the characterization of TiB precipitates, its formation mechanism and influence on α phase precipitation are still not clear. The current work is divided into two parts – (i) understanding the mechanism of TiB formation using first principles based density functional theory (DFT) calculations and (ii) elucidating how TiB influences the α phase morphology and crystallography in titanium alloys using electron microscopy techniques. TiB exhibits anisotropic growth morphology with [010] direction as its predominant growth direction and displays a hexagonal cross section with (100), (101), and (10) as the bounding planes. A high density of stacking faults has been experimentally observed on the (100) plane. The present study, by using DFT based nudged elastic band (NEB) calculations, elucidates for the first time that the diffusion of B through TiB is via an interstitial-assisted mechanism as opposed to vacancy-assisted mechanism hypothesized in literature. This one dimensional interstitial-assisted diffusion results in the anisotropic growth of TiB. In addition, the energetics of TiB- α interfaces was calculated to understand the hexagonal ...
Date: December 2013
Creator: Nandwana, Peeyush
Partner: UNT Libraries