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452 Matching Results
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Investigation on Segmentation, Recognition and 3D Reconstruction of Objects Based on LiDAR Data Or MRI
Segmentation, recognition and 3D reconstruction of objects have been cutting-edge research topics, which have many applications ranging from environmental and medical to geographical applications as well as intelligent transportation. In this dissertation, I focus on the study of segmentation, recognition and 3D reconstruction of objects using LiDAR data/MRI. Three main works are that (I). Feature extraction algorithm based on sparse LiDAR data. A novel method has been proposed for feature extraction from sparse LiDAR data. The algorithm and the related principles have been described. Also, I have tested and discussed the choices and roles of parameters. By using correlation of neighboring points directly, statistic distribution of normal vectors at each point has been effectively used to determine the category of the selected point. (II). Segmentation and 3D reconstruction of objects based on LiDAR/MRI. The proposed method includes that the 3D LiDAR data are layered, that different categories are segmented, and that 3D canopy surfaces of individual tree crowns and clusters of trees are reconstructed from LiDAR point data based on a region active contour model. The proposed method allows for delineations of 3D forest canopy naturally from the contours of raw LiDAR point clouds. The proposed model is suitable not …
Date:
May 2015
Creator:
Tang, Shijun
System:
The UNT Digital Library
Let the Punishment Fit the Crime: an Overview of the Historical Approach to Probation in the State of Texas
Adult probation evolved in the United States as a result of the suspended sentence concept. As a result of a lack of follow through when an individual obtained a suspended sentence, there was no “checks and balances” to monitor whether an individual completed the guidelines set forth. As time progressed, it became apparent a more cohesive and monitored system was needed. Thus, an energetic and motivated individual, John Augustus, started the concept of probation by taking it upon himself to assist in the rehabilitative process of individuals charged with criminal behavior. Subsequent to his death, the concept of probation was embraced by his advocates who lobbied legislatively in order to enact probation laws that would oversee the success of probationers. It wasn’t until the 1950’s that the counties in the state of Texas took it upon themselves to enact their own system of monitoring of probationers. Over time the states have guided their probation concepts from evidence based research. Juvenile probation in the United States didn’t gain a solid foundation until the end of the 19th century with the development of the first juvenile court in Illinois. It took this country time to understand that juveniles were different than adults …
Date:
May 2015
Creator:
Reichstein, Sheldon Philip
System:
The UNT Digital Library
Levanten La Mano Si Me Entienden: Receptive Bilinguals’ Linguistic and Cultural Perceptions in Secondary Spanish Classes
Receptive bilinguals have been in a dilemma of knowing just enough Spanish to write and aurally comprehend the curriculum at the beginning-intermediate levels of a Spanish language course. This dichotomy in classrooms with mixed-ability learners has created a need to reconsider placement and pedagogical structures tailored for these students in foreign language courses. Thus, this descriptive study examined the perceptions of receptive bilinguals, drawn from two secondary Spanish courses regarding receptive bilinguals’ language use, personal Spanish language abilities and confidence, personal beliefs about the language, and contentment with the course. For this study, 31 participants were selected from two public high schools in a suburb of a large metropolitan area in north Texas. Two surveys, a listening assessment and an online questionnaire, were administered at the end of the academic year. The Likert questionnaire items were analyzed using SPSS software, while open-ended questions were coded for recurrent themes. Analyses revealed four major findings. First, with regard to influence on language use, participants’ grandparents created the most interaction with the Spanish language when compared with the other family groups. In addition, Spanish influence through television, literature, radio, and music contributed to students’ early childhood Spanish learning. Second, as to language preference, …
Date:
May 2015
Creator:
Baker, Adelita Gonzales
System:
The UNT Digital Library
The Light of Dark-Age Athens: Factors in the Survival of Athens after the Fall of Mycenaean Civilization
When looking at Dark Age Greece, one of the most important sites to consider is Athens. The Dark Age was a transitional period between the fall of Mycenaean Greece of the Bronze Age, and Archaic Greece of the Iron Age. This period is called the Dark Age because the palaces that ruled the Mycenaean age collapsed, and with them fell civilization in mainland Greece. Writing, fine art, massive architecture, trade, and luxury goods disappear from mainland Greece. But Athens survived the fall of the Mycenaeans. In order to understand the reason why Athens survived one must look at what the causes of the fall of the Mycenaeans were. Theories range from raiders and invasion, to natural disasters, such as earthquakes, droughts, and plagues. One must also examine Greece itself. The landscape and climate of Greece have a large impact on the settlement of the Greeks. The land of Greece also affects what Greek communities were able to do economically, whether a city would be rich or poor. It is because Athens is located in Attica that it survived. Attica had the poorest soil in the Mycenaean world, and was the poorest of the major cities, therefore, when looking at the …
Date:
May 2015
Creator:
Golightly, Paul
System:
The UNT Digital Library
Loading Mode Dependent Effective Properties of Octet-truss Lattice Structures Using 3D-Printing
Cellular materials, often called lattice materials, are increasingly receiving attention for their ultralight structures with high specific strength, excellent impact absorption, acoustic insulation, heat dissipation media and compact heat exchangers. In alignment with emerging additive manufacturing (AM) technology, realization of the structural applications of the lattice materials appears to be becoming faster. Considering the direction dependent material properties of the products with AM, by directionally dependent printing resolution, effective moduli of lattice structures appear to be directionally dependent. In this paper, a constitutive model of a lattice structure, which is an octet-truss with a base material having an orthotropic material property considering AM is developed. In a case study, polyjet based 3D printing material having an orthotropic property with a 9% difference in the principal direction provides difference in the axial and shear moduli in the octet-truss by 2.3 and 4.6%. Experimental validation for the effective properties of a 3D printed octet-truss is done for uniaxial tension and compression test. The theoretical value based on the micro-buckling of truss member are used to estimate the failure strength. Modulus value appears a little overestimate compared with the experiment. Finite element (FE) simulations for uniaxial compression and tension of octet-truss lattice materials …
Date:
May 2015
Creator:
Challapalli, Adithya
System:
The UNT Digital Library
Manipulations of Sucrose/Proton Symporters and Proton-pumping Pyrophosphatase Lead to Enhanced Phloem Transport But Have Contrasting Effects on Plant Biomass
Delivery of photoassimilate, mainly sucrose (Suc) from photoautotrophic source leaves provides the substrate for the growth and maintenance of sink tissues such as roots, storage tissues, flowers and fruits, juvenile organs, and seeds. Phloem loading is the energized process of accumulating solute in the sieve element/companion cell complex of source leaf phloem to generate the hydrostatic pressure that drives long-distance transport. In many plants this is catalyzed by Suc/Proton (H+) symporters (SUTs) which are energized by the proton motive force (PMF). Overexpression of SUTs was tested as means to enhance phloem transport and plant productivity. Phloem specific overexpression of AtSUC2 in wild type (WT) tobacco resulted in enhanced Suc loading and transport, but against the hypothesis, plants were stunted and accumulated carbohydrates in the leaves, possibly due to lack of sufficient energy to support enhanced phloem transport. The energy for SUT mediated phloem loading is provided from the PMF, which is ultimately supplied by the oxidation of a small proportion of the loaded photoassimilates. It was previously shown that inorganic pyrophosphate (PPi) is necessary for this oxidation and overexpressing a proton-pumping pyrophosphatase (AVP1) enhanced both shoot and root growth, and augmented several energized processes like nutrient acquisition and stress responses. …
Date:
May 2015
Creator:
Khadilkar, Aswad S
System:
The UNT Digital Library
Mapping Overlapping Constellations: Nature and Technology in Research in Philosophy and Technology/Techné and Environmental Ethics
The overlap between the separate fields of philosophy of technology and environmental philosophy can be investigated using the two longest running flagship journals for each field, Environmental Ethics (EE) and Research in Philosophy and Technology, which is now published as Techné: Research in Philosophy and Technology (RPT/Techné). By looking at the theoretical and conceptual ideas on nature and the environment expressed in RPT/Techné, at those on technology and artifacts expressed in EE, and at the individuals who contributed them using the principles of social epistemology as developed by Steve Fuller, a stereoscopic view incorporating the insights from both specializations can be constructed. The ideas developed in the articles can be charted like stars within constellations, loosely connected in groupings that are neither clear nor evident. Five constellations can be discerned from the relevant articles in each journal, and while there is some overlap, there is considerable difference. The stereoscopic view is developed in three ways: first, by reviewing the contributions of authors who have published in both journals; second, by utilizing resources in both specializations to add subtlety and depth to the ideas expressed, starting in this case from Jacques Ellul’s “Nature, Technique and Artificiality”; and third, by using W. …
Date:
May 2015
Creator:
Miller, Glen, 1975-
System:
The UNT Digital Library
Marital Status and Racial/Ethnic Differences in Health Outcomes
Substantial evidence demonstrates that marriage is associated with better health outcomes and lower mortality risk. Some evidence suggests that there are gender and race/ethnicity differences between the marriage-health benefits association. However, previous studies on marriage and health have mainly focused on non-Hispanic White-Black differences. Limited information is available regarding the roles of Hispanics. The present study examined marital status, gender, and the differences between non-Hispanic Whites, non-Hispanic Blacks, and Hispanics, in health outcomes. A retrospective cohort analysis of 24,119 Hispanic, NH White, and NH Black adults admitted to a large hospital was conducted. A total of 16,661 patients identified as either married or single was included in the final analyses. Consistent with the broader literature, marriage was associated with beneficial hospital utilization outcomes. With respect to differences in these benefits, results suggest that married patients, Hispanic patients, and women, were less likely to experience in-hospital mortality. Similar effects were observed in aggregated length of stay with married Hispanic women hospitalized nearly 2 days less than their single counterparts (6.83 days and 8.66 days, respectively). These findings support existing literature that marriage is associated with health benefits, add to the emerging research of a Hispanic survival advantage, and broaden the understanding …
Date:
May 2015
Creator:
Villarreal, Cesar
System:
The UNT Digital Library
Marvels of the Invisible
This dissertation is comprised of a collection of poems preceded by a critical preface. The preface considers the consumed animal body as a metaphor in contemporary American poetry, specifically in the works of Galway Kinnell, Li Young Lee, and Brigit Pegeen Kelly. The consumption of the mute creature allows the poet to identify the human self in the animal other, and serves as a metaphor for our continuity with the natural world. I revise Owen Barfield’s notion of “original participation,” positing that through imaginative participation, the poet and the reader can identify the animal within the self, and thus approach a fuller understanding of both the self and the outside world. We identify the animal other within the human self, and in of this act of relating, we are able to temporarily transgress the boundaries of the individual self to create art that expresses continuity with the outside world. This argument brings about a discussion of text as an act of consumption, and the way and which this can symbolize the ways in which the self is altered through the act of reading. The book-length collection of poems, entitled Marvels of the Invisible, won Tupelo Press’s 2014 Berkshire prize for …
Date:
May 2015
Creator:
Molberg, Jenny, 1985-
System:
The UNT Digital Library
The Mechanisms of Human Glutathione Synthetase and Related Non-Enyzmatic Catalysis
Human glutathione synthetase (hGS) is a homodimeric enzymes that catalyzes the second step in the biological synthesis of glutathione, a critical cellular antioxidant. The enzyme exhibits negative cooperativity towards the γ-glutamylcysteine (γ-GC) substrate. In this type of allosteric regulation, the binding of γ-GC at one active site significantly reduces substrate affinity at a second active site over 40 Å away. The presented work explores protein-protein interactions, substrate binding, and allosteric communication through investigation of three regions of hGS: the dimer interface, the S-loop, and the E-loop. Strong electrostatic interactions across the dimer interface of hGS maintain the appropriate tertiary and quaternary enzymatic structure needed for activity. The S-loop and E-loop of hGS form walls of the active site near γ-GC, with some residues serving to bind and position the negatively cooperative substrate. These strong interactions in the active site serve as a trigger for allosteric communication, which then passes through hydrophobic interactions at the interface. A comprehensive computational and experimental approach relates hGS structure with activity and regulation. ATP-grasp enzymes, including hGS, utilize ATP in the nucleophilic attack of a carboxylic acid in a reaction thought to proceed through the formation of an acylphosphate intermediate. Small metal cations are known …
Date:
May 2015
Creator:
Ingle, Brandall L.
System:
The UNT Digital Library
The Microbial Retting Environment of Hibiscus Cannabinus and Its Implications in Broader Applications
Fiber-yielding plants is an area of increased interest due to the potential use in a variety of green-based materials. These biocomposites can be incorporated into multiple uses; for example, to replace building materials and interior vehicular paneling. The research here aims to focus in on the crop Hibiscus cannabinus for utilization into these functions. H. cannabinus is economically attractive due to the entire process being able to be accomplished here in the United States. The plant can be grown in a relatively short growth period (120-180 days), and then processed and incorporated in a biocomposite. The plant fiber must first be broken down into a useable medium. This is accomplished by the retting process, which occurs when microbial constituents breakdown the heteropolysaccharides releasing the fiber. The research aims to bridge the gap between the primitive process of retting and current techniques in molecular and microbiology. Utilizing a classical microbiological approach, which entailed enrichment and isolation of pectinase-producing bacteria for downstream use in augmented microbial retting experiments. The tracking of the bacteria was accomplished by using the 16S rRNA which acts as “barcodes” for bacteria. Next-generation sequencing can then provide data from each environment telling the composition and microbial diversity of …
Date:
May 2015
Creator:
Visi, David K.
System:
The UNT Digital Library
"Miss Kathy"
Miss Kathy is a documentary film that tells the story of Kathy Griffin-Grinan, a lead recovery coach for prostitution and human trafficking with the Harris County Sheriff’s Office. Her non-profit organization —We’ve Been There, Done That – works in conjunction with law-enforcement to offer the survivors of prostitution a chance at rehabilitation. With endless enthusiasm, she mentors survivors as they struggle to escape a destructive lifestyle. This film also explores the relationship between human trafficking and prostitution, while addressing issues of victimization and exploitation.
Date:
May 2015
Creator:
Alexander, Jeffrey, 1982-
System:
The UNT Digital Library
Modern Forms of an Ancient Art: A Selection of Contemporary Fanfares for Multiple Trumpets Demonstrating Evolutionary Processes in the Fanfare Form
The pieces discussed throughout this dissertation provide evidence of the evolution of the fanfare and the ability of the fanfare, as a form, to accept modern compositional techniques. While Britten’s Fanfare for St. Edmundsbury maintains the harmonic series, it does so by choice rather than by the necessity in earlier music played by the baroque trumpet. Stravinsky’s Fanfare from Agon applies set theory, modal harmonies, and open chords to blend modern techniques with medieval sounds. Satie’s Sonnerie makes use of counterpoint and a rather unusual, new characteristic for fanfares, soft dynamics. Ginastera’s Fanfare for Four Trumpets in C utilizes atonality and jazz harmonies while Stravinsky’s Fanfare for a New Theatre strictly coheres to twelve-tone serialism. McTee’s Fanfare for Trumpets applies half-step dissonance and ostinato patterns while Tower’s Fanfare for the Uncommon Woman demonstrates a multi-section work with chromaticism and tritones. By applying modern compositional techniques to an older, abstract form, composers have maintained the original aesthetic while allowing for fanfares to be used as concert music. This document adds to the limited body of scholarly writing on modern fanfares.
Date:
May 2015
Creator:
Florek, Paul J.
System:
The UNT Digital Library
The Modern Trombone in the African American Church: Shout Bands and the African American Preacher in the United House of Prayer
The United House of Prayer was established by Marcelino Manuel da Graça (1881-1960), who is also known as Charles Manuel “Sweet Daddy” Grace, or “Daddy” Grace. He founded and developed the use of the shout bands which are charismatic gospel trombone ensembles within this church. This study explores the importance of shout bands and examines them from multiple perspectives focusing in particular on worship practices. Additionally, it examines rhythmic elements as the most important characteristic of music performed by these unique ensembles, rhythms that reflect the preacher’s personal timing and inflections that the trombones then imitate. The approach used here supports a deeper understanding of the United House of Prayer and of the trombone in church services of this denomination. Indeed, it ultimately establishes the trombone’s role in the United House of Prayer.
Date:
May 2015
Creator:
Block, Tyrone J.
System:
The UNT Digital Library
A Multimodal Investigation of Renewal of Human Avoidance, Perceived Threat, and Emotion
Many people who receive exposure-based treatments for anxiety disorders exhibit a return of fear and avoidance which is often referred to as renewal or relapse. Human and nonhuman research on fear conditioning and renewal has been instrumental in helping understand relapse in anxiety disorders. The purpose of this investigation was to examine renewal of human avoidance and assess whether avoidance may aid in sustaining renewal of fear responses. We adopted a multimodal measurement approach consisting of an approach-avoidance task along with ratings of perceived threat and fear and measures of skin-conductance, a widely used physiological measure of fear. A traditional, single-subject research design was used with six healthy adults. All tasks employed a discrete trial procedure. Experimental conditions included Pavlovian fear conditioning in which increased probability of money loss was paired with a “threat” meter in Context A and later followed extinction in Context B. Fear and avoidance increased to higher threat levels in Context A but not Context B. Renewal testing involved presenting the threat meter on a return to Context A to determine if it evoked fear and avoidance (i.e., relapse). As predicted, renewal testing in Context A showed that increased threat was associated with increased avoidance, ratings …
Date:
May 2015
Creator:
Ludlum, Madonna L.
System:
The UNT Digital Library
Nanohybrids Based on Solid and Foam Polyurethanes
Polymer nanocomposites are a going part of Materials Science and Engineering. These new composite materials exhibit dimensional and thermal stability of inorganic materials and toughness and dielectric properties of polymers. Development of nanocomposites become an important approach to create high-performance composite materials. In this study silica, fly ash, silica nanotubes and carbon black particles have been added to modify polyurethane foam and thermoplastic polyurethanes. It has been found that the addition of silica can diminish the size of foam bubbles, resulting in an increased stiffness of the material, increase of the compressive strength, and greater resistance to deformation. However, the uniformity of bubbles is reduced, resulting in increased friction of the material. Fly ash added to the foam can make bubbles smaller and improve uniformity of cells. Therefore, the material stiffness and compressive strength, resistance to deformation, and has little impact on the dynamic friction of the material. Adding nanotubes make bubble size unequal, and the arrangement of the bubble uneven, resulting in decreased strength of the material, while the friction increases. After the addition of carbon black to the polyurethane foam, due to the special surface structure of the carbon black, the foam generates more bubbles during the foaming …
Date:
May 2015
Creator:
Bo, Chong
System:
The UNT Digital Library
Neurotoxicity of the Industrial Solvent 4-Methylcyclohexanemethanol: Involvement of the GABA Receptor
A recent chemical spill of 4-Methylcyclohexanemethanol (4-MCHM) in West Virginia left 300,000 people without water. Officials claimed that this compound is not lethally toxic, but potentially harmful if swallowed or inhaled, and can cause eye and skin irritation. Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens reports high exposures from skin contact or inhalation may cause damage to the heart, liver, kidneys, and lungs, and may result in death. However, no quantitative data seem to exist and no references can be found on neurotoxicity. We have investigated the neurotoxicity of 4-MCHM using mammalian nerve cell networks grown on microelectrode arrays. Network spontaneous activity from multiple units (range 48 – 120 per network) were used as the primary readout. Individual units were followed based on spike waveforms digitized at 40 kHz (Plexon MNAP system). Dose response curves show the effective inhibitory concentration at 50 percent decrease (EC50) to average 27.4 microM SD±6.17. However, in the presence of 40 microM bicuculline, a competitive GABAA antagonist, the EC50 shifts to 70.63uM SD ±4.3; implying that early, low concentration exposures to 4-MCHM involve GABA activation. Initial activity loss occurs without active unit loss (defined as 10 or more template threshold crossing per min), indicating …
Date:
May 2015
Creator:
Gibson, Jason (Jason Robert)
System:
The UNT Digital Library
The Nothingness of Presence: Sound, Ritual, and Encounter in the Music of Into Your Hands
The ritual music written for the Compline service of the Liturgy of the Hours, Into Your Hands, is analyzed using an ontological and phenomenological approach, which seeks to answer how such sound/musical phenomena wed to the specific ritual dynamics of Compline in their own right can create a potential for encounter with the Divine. The Jewish philosopher Martin Buber’s understanding of encounter is used to show that the sound/musical phenomena in itself bears similarities with the nature of the Judeo/Christian God, and such a nature is revealed to be both irreducibly non-conceptual as well as an entity that establishes the ontological actuality of one’s being. Studies in the beginnings of humanity at large as well as the beginnings of the individual fetus reveal that an integrated expression of music and ritual can be said to have formed the impetus of such ontological beginnings through encounter. Therefore, one of the first sounds heard in the womb - that of water (or amniotic fluid) - constitutes what may be an archetypal sound of encounter. The phenomenological effects of such an archetype are analyzed in the music of Into Your Hands through topics such as the loss of aural perspective, immersion, dynamic swells, …
Date:
May 2015
Creator:
Evans, Eric
System:
The UNT Digital Library
The Palestinian Archipelago and the Construction of Palestinian Identity After Sixty-five Years of Diaspora: the Rebirth of the Nation
This dissertation conceptualizes a Palestinian archipelago based on Mikhail Bakhtin’s theory of the chronotope, and uses the archipelago model to illustrate the situation and development of Palestinian consciousness in diaspora. To gain insight into the personal lives of Palestinians in diaspora, This project highlights several islands of Palestinian identities as represented in the novels: Dancing Arabs, A Compass for the Sunflower, and The Inheritance. The identities of the characters in these works are organized according to the archipelago model, which illustrates how the characters rediscover, repress, or change their identities in order to accommodate life in diaspora. Analysis reveals that a major goal of Palestinian existence in diaspora is the maintenance of an authentic Palestinian identity. Therefore, my description of the characters’ identities and locations in the archipelago model are informed by various scholars and theories of nationalism. Moreover, this dissertation illustrates how different Palestinian identities coalesce into a single national consciousness that has been created and sustained by a collective experience of suffering and thirst for sense of belonging and community among Palestinians. Foremost in the memories of all Palestinians is the memory of the land of Palestine and the dream of national restoration; these are the main uniting …
Date:
May 2015
Creator:
Shaheen, Basima
System:
The UNT Digital Library
Participant Perspectives: Investigating the Experience of Low-Income Schizophrenics in Clinical Research Trials
The continued investigation into the experiences of individuals with schizophrenia who participate in biomedical research trials is necessary in order to understand participants’ perspectives, motivations, attitudes, values, and beliefs. As important stakeholders in the clinical research process, participant feedback is significant and can help shed light on, not only their experiences, but also deepen understandings when it comes to clinical trial participants’ perceptions of informed consent and personal autonomy. Conducting ethical research demands the exploration of these issues and specifically targeting this vulnerable group helped to address a gap in the literature. This study was conducted for InSite Clinical Research and gathered data in the form of in-depth semi-structured interviews and a short survey instrument with 20 low-income adults diagnosed with schizophrenia that participate in clinical research trials. Findings indicate overall positive research experiences, with motivations aligning with previous research when it comes to trial participation including: altruism, personal benefit, access to medications, financial incentives, and psychosocial treatment. Learning about their illness and themselves, autonomy, and debriefing were also particularly important within this group. Unique to this sample were findings of friendship. Trust in the research staff was identified as a major underlying value and shaping factor impacting informed consent …
Date:
May 2015
Creator:
Green, Asha M.
System:
The UNT Digital Library
Pastoral Livelihoods and Household Water Management in the Central Argentine Andes
Pastoralists tend to occupy highlands and drylands lands with uncertain climates and are experienced at coping with climatic variability and drought. Increasingly, however, the speed with which climate patterns are changing has become an issue of concern. This study examines household water management strategies of pastoralists in western Argentina. In this semi-arid region, pastoralists rely primarily on streams and springs fed by snow and glacier melt from the Andes, and have developed various strategies to meet their water needs. They also deal with myriad challenges posed by climate, economic, and socio-cultural change and work vigorously to maintain their herds – a combination of cattle, goats, and sheep – in this water scarce region. The goal of this study is to understand: 1) different household water management strategies; 2) the ways pastoral livelihoods are changing in response to changes in water supply; and 3) the socio-economic changes that affect pastoral livelihoods. Information from interviews, household surveys, and participant observations reveals that climate fluctuation impacts water supplies and use, herd size, and expenses made on tanks, technology, and infrastructure for the storage and transport of water, food for animals, and subsistence crops. Understanding the micro-scale, water practices of pastoral households provides insight …
Date:
May 2015
Creator:
Parker, Julie
System:
The UNT Digital Library
Pathways for C—H Activation and Functionalization by Group 9 Metals
As fossil fuel resources become more and more scarce, attention has been turned to alternative sources of fuels and energy. One promising prospect is the conversion of methane (natural gas) to methanol, which requires an initial activation of a C-H bond and subsequent formation of a C-O bond. The most well studied methodologies for both C-H activation and C-O bond formation involve oxidation of the metal center. Metal complexes with facile access to oxidation states separated by four charge units, required for two subsequent oxidations, are rare. Non-oxidative methods to perform C-H bond activation or C-O bond formation must be pursued in order for methane to methanol to become a viable strategy. In this dissertation studies on redox and non-redox methods for both C-H activation and C-O bond formation are discussed. In the early chapters C-O bond formation in the form of reductive functionalization is modeled. Polypyridine ligated rhodium complexes were studied computationally to determine the properties that would promote reductive functionalization. These principles were then tested by designing an experimental complex that could form C-O bonds. This complex was then shown to also work in acidic media, a critical aspect for product stabilization. In the later chapters, non-oxidative C-H …
Date:
May 2015
Creator:
Pahls, Dale R.
System:
The UNT Digital Library
Patient Family and Hospital Staff Information Needs at a Pediatric Hospital: an Analysis of Information Requests Received by the Family Resource Libraries
This research explored the information needs of patient families and hospital staff at a pediatric hospital system in Dallas, Texas. Library statistics recorded in four hospital libraries from 2011 - 2013 were used to analyze the information requests from patient families and hospital staff. Crosstabulations revealed the extent to which patient families and hospital staff used the libraries to satisfy their information needs. The data showed that patient families used the libraries very differently than hospital staff. Chi-square tests for independence were performed to identify the relationships between the Classification (Patient Family, Hospital Staff) and two descriptors of information needs (Request Type, Resources Used). There were a total of 1,406 information requests analyzed. The data showed that patient families and hospital staff information requests differed greatly in the number of information requests, the type of information requested, the resources used and the time the library staff spent on the requests. Chi-square analyses revealed relationships statistically significant at the p < .05 level; however, the strength of the relationships varied.
Date:
May 2015
Creator:
Rutledge, M. Hannah
System:
The UNT Digital Library
Peer Networks and Health Risk Behaviors Among Adolescents
Adolescence is a time of great exploration and change. During this time, youth are transitioning both biologically and sexually into adults. Adolescents are also testing the boundaries of self-reliance and making choices about their personal relationships. Not surprisingly, aggressive urges are often driven by peers in pursuit of some form of identity (Masten 2004). Peers can have both positive and negative effects on the wellbeing on youth. Peer groups can provide emotional, physical, and social support to youth during a time of immense change (Parker and Asher 1987; Gest, Graham-Berman, and Hartup 2001). Peers can also model delinquent and risk-taking behaviors that have lasting health, social, and economic consequences throughout the life course. In an effort to understand the role of friendships in adolescent health, social scientists have increasingly focused on adolescent network structures within schools and the role various positions and peer group formations influence behaviors such as alcohol and cigarette use, violent and serious delinquency, and sexual risk-taking. While informative, peer networks studies have yet to adequately address how peer network structures based on immigrant generation and types of marginalized social positions influence health risk behavior engagement among adolescents. In three studies, I address the dearth of research …
Date:
May 2015
Creator:
Niño, Michael David
System:
The UNT Digital Library