UNT Theses and Dissertations - 18,551 Matching Results

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Community of Inquiry Meets Critical Discourse Analysis (CDA): A CDA of Asynchronous Computer-Conference Discourse with Seminary Students in India

Description: The purpose of this study was to better understand student learning in asynchronous computer-conference discourse (ASD) for non-native speakers of English in India through the Community of Inquiry (COI) framework. The study looked at ASD from an online course taught in the fall of 2015 to 25 students in a seminary in South India. All but one of the students were non-native speakers of English. The class consisted of 22 men and 3 women. Eight students spoke languages from the Dravidian family of languages (Malayalam, Tamil, Telegu and Kannada). Eight students were from the Northeastern states of Manipur, Nagaland and Tripura, where most languages are from the Sino-Tibetan family. Three students were native speakers of Indo-Aryan languages (Odiya and Assamese). Five students were from Myanmar representing several Sino-Tibetan languages. The COI is a framework used to understand learning in ASD, often used in online learning. To study the ASD of this group, critical discourse analysis (CDA) was used with the COI to capture the unique socio-cultural and linguistic conditions of this group. The study revealed that non-native speakers of English often reach the Exploration phase of learning but rarely show evidence of reaching the Resolution phase. This phenomenon was also observed in native English speakers as reported in the literature. Also, the structure of ASD showed that students took an examination approach to discussion shaped in part by their epistemology. This examination approach shaped how knowledge was constructed. CDA also showed that the discourse acquired an instructor-centered structure in which Resolution and Repair were initiated and finalized by the instructor. The study advances the COI framework by undergirding it with a theory of asynchronous discourse using critical discourse analysis and capturing cognitive, social and teaching presence phenomena for non-native speakers that were not observed through the traditional COI framework. These ...
Date: August 2017
Creator: George, Stephen J
Partner: UNT Libraries

A Case Study of Mathematics Teachers' Use of Short-Cycle Formative Assessment Strategies

Description: A single case study was used to examine two middle grades mathematics teachers' use of short-cycle formative assessment strategies. Data was collected using multiple sources to provide a description of this single case. Participant change in knowledge of short-cycle formative assessment strategies was collected and analyzed through participant pre- and post-interviews and targeted instructional support was provided through professional development sessions designed to meet diverse needs of participants. Participant change in use of short-cycle formative assessment strategies was collected and analyzed through classroom observations using Assess Today observation protocol and targeted instructional support was provided through post-observation conferences with written feedback. Findings from the study verified that changes in teachers' use of short-cycle formative assessment strategies were positively influenced by the targeted instructional support provided to each participant during the study. The study further indicated that an assessment of teacher's present knowledge and use of short-cycle formative assessment strategies should be considered before providing targeted instructional support to maximize the learning potential for each teacher. Future research is needed regarding the importance of building student self-efficacy through teacher use of short-cycle formative assessment, as well as the importance of involving students in the formative assessment process.
Date: August 2017
Creator: Davis, Adreana A
Partner: UNT Libraries

Microwave-Assisted Synthesis and Photophysical Properties of Poly-Imine Ambipolar Ligands and Their Rhenium(I) Carbonyl Complexes

Description: The phenomenon luminescence rigidochromism has been reported since the 1970s in tricarbonyldiimine complexes with a general formula [R(CO)3LX] using conventional unipolar diimine ligands such as 2,2;-bipyridine or 1,10-phenanthroline as L, and halogens or simple solvents as X. As a major part of this dissertation, microwave-assisted synthesis, purification, characterization and detailed photoluminescence studies of the complex fac-[ReCl(CO)3L], 1, where L = 4-[4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl]-N,N-diethylbenzenamine are reported. The employment of microwaves in the preparation of 1 decreased the reaction time from 48 to 2 hours compared to the conventional reflux method. Stoichiometry variations allows for selective preparation of either a mononuclear, 1, or binuclear, fac-[Re2Cl2(CO)6], 2, complex. The photophysical properties of 1 were analyzed finding that it possesses significant luminescence rigidochromism. The steady state photoluminescence emission spectra of 1 in solution shift from 550 nm in frozen media to 610 nm when the matrix becomes fluid. Moreover, a very sensitive emission spectral analysis of 0.1 K temperatures steps shows a smooth transition through the glass transition temperature of the solvent host. Furthermore, synthetic modifications to L have attained a family of ambipolar compounds that have tunable photophysical, thermophysical and other material properties that render them promising candidates for potential applications in organic electronics and/or sensors - either as is or for their future complexes with various transition metals and lanthanides.
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Date: August 2017
Creator: Salazar Garza, Gustavo Adolfo
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The King Arrives: Chinese Government Inspections and Their Effects

Description: This dissertation studies a critical facet of Chinese politics, inspections by higher Chinese government to villages. Principally, it looks at how village economic development determines government inspection decisions and how inspections, once conducted, impact village politics. Specifically, I argue that villages perceived as destabilizing to the Chinese regime, villages with higher levels of economic inequality and villages located at the two extremes of economic development, should see more inspections. In addition, I argue that inspections, in return, drive village politics: they increase village leaders' governing efficacy and raise villagers' political awareness. This theory has received strong support from both field work and quantitative empirical tests using the Chinese Household Income Project (2002) dataset.
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Date: August 2017
Creator: Xi, Jinrui
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Mobile-Based Smart Auscultation

Description: In developing countries, acute respiratory infections (ARIs) are responsible for two million deaths per year. Most victims are children who are less than 5 years old. Pneumonia kills 5000 children per day. The statistics for cardiovascular diseases (CVDs) are even more alarming. According to a 2009 report from the World Health Organization (WHO), CVDs kill 17 million people per year. In many resource-poor parts of the world such as India and China, many people are unable to access cardiologists, pulmonologists, and other specialists. Hence, low skilled health professionals are responsible for screening people for ARIs and CVDs in these areas. For example, in the rural areas of the Philippines, there is only one doctor for every 10,000 people. By contrast, the United States has one doctor for every 500 Americans. Due to advances in technology, it is now possible to use a smartphone for audio recording, signal processing, and machine learning. In my thesis, I have developed an Android application named Smart Auscultation. Auscultation is a process in which physicians listen to heart and lung sounds to diagnose disorders. Cardiologists spend years mastering this skill. The Smart Auscultation application is capable of recording and classifying heart sounds, and can be used by public or clinical health workers. This application can detect abnormal heart sounds with up to 92-98% accuracy. In addition, the application can record, but not yet classify, lung sounds. This application will be able to help save thousands of lives by allowing anyone to identify abnormal heart and lung sounds.
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Date: August 2017
Creator: Chitnis, Anurag Ashok
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A Woman's Place is at Work: The Rise of Women's Paid Labor in Five Texas Cities, 1900-1940

Description: This thesis is a quantitative analysis of women working for pay aged sixteen and older in five mid-size Texas cities from 1900 to 1940. It examines wage-earning women primarily in terms of race, age, marital status, and occupation at each census year and how those key factors changed over time. This study investigates what, if any, trends occurred in the types of occupations open to women and the roles of race, age, and marital status in women working for pay in the first forty years of the 20th century.
Date: August 2017
Creator: Scott, Codee
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A Systemic Model for Family Functioning: Mutual Influences of Spousal Attachment, Marital Adjustment, and Coparenting

Description: The current study examined direct and indirect influences of romantic attachment processes, marital adjustment, and the coparenting relationship on family functioning. Data was collected from a community sample of 86 heterosexual couples with a child aged eight to eleven living in the home. Both spouses completed a demographic questionnaire, the Experiences in Close Relationships Scale, the Dyadic Adjustment Scale, the Coparenting Scale, and the Self-Report Family Inventory as part of a larger study on family processes in middle childhood. Data analysis included multilevel modeling, utilizing the actor-partner interdependence model. Results indicated that marital adjustment mediated the association between attachment processes and family functioning, suggesting that a healthy marital relationship is an important variable that helps explain links between attachment security and the family functioning. Findings also highlighted the benefit of conceptualizing adult romantic attachment, marital, and coparental subsystems within a systemic framework.
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Date: August 2017
Creator: Young, Anne Michelle
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"Momentarium"

Description: "Momentarium" is a collection of poems that examines the instability of moments. By engaging with photography, the poems examine the strengths and flaws in representation. Qualified accuracy, in other words representations that exact no absolute authenticity, are paradoxically, most accurate. The original poems attempt to express both empathy an end to empathy, "I mean to give you what you cannot keep: a blue twice as true" and "I mean to give you what I cannot." The competing forces animate a contingent moment, before it becomes the past.
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Date: August 2017
Creator: Zuehlke, Karl
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Best Practices in Targeted Advertising for Fashion Entrepreneurs

Description: A key to a business's success is reaching the target market. This ensures that consumers are exposed to the retailer's offerings and by turn, inspired to purchase. In turn, the business can reach its goal of a profitable organization. The purpose of this paper was to determine the most effective fashion advertising appeals for reaching target markets. To address these issues, this thesis consisted of two studies. The purpose of the first study was to determine the advice given to fashion entrepreneurs regarding effective target market practices. The purpose of the second study was to determine effective advertising strategies fashion entrepreneurs may employ for effectively reaching target markets. Data was collected to test the effectiveness of the advice from Study 1, degrees of brand awareness, attitudes towards advertising, willingness to follow trends, purchase intention, purchase behavior, and shopping involvement. The Theory of Reasoned Action was employed as the theoretical framework of the study. The framework was utilized to predict that attitudes towards targeted advertising and pressure to follow fashion trends would positively relate to intent to purchase which, in turn, would positively relate to purchase behavior. The results of this paper concluded the TRA model provided a proper framework to predict purchase behavior from targeted advertising employed by fashion entrepreneurs.
Date: August 2017
Creator: Slaton, Kelcie Shaelyn
Partner: UNT Libraries

Investigation of Immersion Cooled ARM-Based Computer Clusters for Low-Cost, High-Performance Computing

Description: This study aimed to investigate performance of ARM-based computer clusters using two-phase immersion cooling approach, and demonstrate its potential benefits over the air-based natural and forced convection approaches. ARM-based clusters were created using Raspberry Pi model 2 and 3, a commodity-level, single-board computer. Immersion cooling mode utilized two types of dielectric liquids, HFE-7000 and HFE-7100. Experiments involved running benchmarking tests Sysbench high performance linpack (HPL), and the combination of both in order to quantify the key parameters of device junction temperature, frequency, execution time, computing performance, and energy consumption. Results indicated that the device core temperature has direct effects on the computing performance and energy consumption. In the reference, natural convection cooling mode, as the temperature raised, the cluster started to decease its operating frequency to save the internal cores from damage. This resulted in decline of computing performance and increase of execution time, further leading to increase of energy consumption. In more extreme cases, performance of the cluster dropped by 4X, while the energy consumption increased by 220%. This study therefore demonstrated that two-phase immersion cooling method with its near-isothermal, high heat transfer capability would enable fast, energy efficient, and reliable operation, particularly benefiting high performance computing applications where conventional air-based cooling methods would fail.
Date: August 2017
Creator: Mohammed, Awaizulla Shareef
Partner: UNT Libraries

Are Streams Protected? Outcomes of Environmental Regulation

Description: Urban areas experience the loss of natural stream channels through conversion to artificial conveyances. This process tends to target headwater and other low order streams. The purpose of this study is to determine the patterns of stream loss in Denton, Texas, and explore the regulatory structure that manages these streams. Historic and current maps and stream data are used to map Denton's streams and categorize them according to their vertical connectivity as: 1) "intact", streams that are open to the atmosphere and connect to groundwater; 2) "concrete", channelized streams open to the atmosphere but cut off from groundwater; and 3) "buried", streams disconnected from the atmosphere and groundwater. A review of federal, state, and local regulatory codes and interviews with local government officials and other stakeholders elucidates stream management in Denton. Results from these analyses reveal high rates of stream loss in the urban center with low rates overall. The federal Clean Water Act and the local Environmentally Sensitive Areas code serve as the primary protective measures for natural streams. These regulations discourage stream impacts through expensive and complex permitting requirements. However the policies allow minor impacts which may cause cumulative effects. This study aims to inform future policy-making decisions and contribute to the knowledge of the environmental regulation of streams.
Date: August 2017
Creator: Rowen, Zachary
Partner: UNT Libraries

Predictors of Postsecondary Success: An Analysis of First Year College Remediation

Description: This study was a quantitative multiple regression investigation into the relationships between campus factors of high school students graduating in 2013 who immediately enrolled in first-year college freshman level remedial coursework at a large, Central Texas two-year postsecondary institution. The goal of this study was to determine which high school campus-level factors predicted enrollment into college remedial education coursework. The dependent variable was a continuous variable representing the percentage of students from Texas public high school campuses enrolled into at least one student credit hour of remedial education during their first semester as a first-year college student. Eight high school campus-level independent variables were included in the regression model at the campus-level: at risk percentage, economically disadvantaged percentage, limited English proficient percentage, advanced course/dual-enrollment percentage, college ready math percentage, college ready English percentage, ACT average, and SAT average. Pearson correlations and linear regression results were examined and interpreted to determine the level of relationship between the eight selected variables and first-year college student remedial coursework. The multiple regression model successfully explained 26.3% (F(8,286) = 12.74. p < 0.05, r2 = 0.263) of the variance between first-year college students enrolled into remedial coursework at a large, Central Texas two-year postsecondary institution and the campus-level variables from high schools from which they graduated and indicated campus-level economic disadvantaged percentage and campus-level SAT average to be statistically significant at the p < 0.05 level.
Date: August 2017
Creator: Baker, Emmett Andrew
Partner: UNT Libraries

Effect of Surface Treatment on the Performance of CARALL, Carbon Fiber Reinforced Aluminum Joints

Description: Fiber-metal laminates (FML) are the advanced materials that are developed to improve the high performance of lightweight structures that are rapidly becoming a superior substitute for metal structures. The reasons behind their emerging usage are the mechanical properties without a compromise in weight other than the traditional metals. The bond remains a concern. This thesis reviews the effect of pre-treatments, say heat, P2 etch and laser treatments on the substrate which modifies the surface composition/roughness to impact the bond strength. The constituents that make up the FMLs in our present study are the Aluminum 2024 alloy as the substrate and the carbon fiber prepregs are the fibers. These composite samples are manufactured in a compression molding process after each pre-treatment and are then subjected to different tests to investigate its properties in tension, compression, flexural and lap shear strength. The results indicate that heat treatment adversely affects properties of the metal and the joint while laser treatments provide the best bond and joint strength.
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Date: August 2017
Creator: Bandi, Raghava
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A Mixed Methods Approach to Exploring Social Support and Resilience in Coping with Stigma and Psychological Distress among HIV-Positive Adults

Description: Since its emergence in the U.S., HIV has been a stigmatized illness. People living with HIV (PLH) are a minority and prone to psychological distress and poor mental health outcomes due to HIV-related stigma. PLH who identify with another minority group in addition to being HIV-positive (e.g., gay, African-American) experience multiple forms of oppression or layered stigma. Affirmative social support and resilience are negatively associated with HIV-stigma and are important coping resources for PLH. We used an explanatory sequential mixed methods design study involving a quantitative survey phase and a qualitative interview phase. We explored whether social support and resilience (Positive Psychological Resources) mediate or moderate the relationship between HIV Stigma and Psychological Distress among HIV-positive adults using partial least squares (PLS) path modeling and multiple regressions. Via PLS, we found Positive Psychological Resources partially mediated the relationship between HIV Stigma and Psychological Distress: the path between HIV Stigma and Psychological distress reduced (from t = 5.49, p = .000 to t = 2.39, p = .000) but remained statistically significant. Similarly, via regression, the Sobel test was significant (Sobel = .26, SE = .07, z = 3.63, p = .000). However, moderation was not found (HIV Stigma x Positive Psychological Resources β = .05, t = .66, p = .508). Overall, our quantitative survey and qualitative interview data were consistent. We anticipate that our findings will inform strengths-based therapeutic interventions to mitigate stress and stigma among PLH.
Date: August 2017
Creator: Fritz, Sarah-mee
Partner: UNT Libraries

Educational Uplift along the US-Mexico Border: How Students, Families, and Educators Cultivate a College-Going Culture in Contested Terrain

Description: Using critical race theory and LatCrit as conceptual frameworks, I conducted a qualitative instrumental case study of a cadre of self-identified Mexican-American and Hispanic college students who bring college knowledge, goodwill, and aid to their border town communities. The purpose of this study was to explore how college knowledge and other forms of academic capital are transmitted and co-constructed in the contested terrain of the borderlands. Primary data sources included semi-structured interviews, participant and non-participant observation, and personal artifacts (e.g. newspaper articles, college admissions essays, social media, etc.) collected from 17 full-time undergraduate student participants, 11 males and 6 females, ranging from 19 to 22 years old, who were active members of the Gates Millennium Scholars Program. Supplemental data sources included semi-structured interviews with 23 family members and 9 educators identified by student participants, as well as a review of public records regarding student participant's border town communities (e.g. newspaper articles, census data, educational statistics, etc.). Findings detail how this group of college students manages the 'scholar' distinction in their hometown and utilizes distinct methods to promote academic capital formation. Specifically, this study delineates the following four types of scholars: (1) pioneers, (2) guardians, (3) ambassadors, and (4) advocates. Ultimately, this research highlights the importance of college students' ingenuity in response to enduring system inequality in higher education, particularly along the U.S.-Mexico border, with implications for research theory, policy, and practice.
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Date: August 2017
Creator: Sanchez, Nydia C
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Social Support as a Moderator of Racial/Ethnic Differences in Subclinical Atherosclerosis: The North Texas Heart Study

Description: This study examined racial/ethnic differences in pre-clinical disease, social support, and tested whether social support was a moderator of racial/ethnic differences in subclinical atherosclerosis. Participants were NHWs, NHBs, and Latinos (n = 283) from the baseline and cross-sectional sample of the North Texas Heart Study. Results from unadjusted models showed no significant racial/ethnic differences for common or bifurcation intima-media thickness (cIMT). However, unadjusted models for cIMT showed a main effect for race/ethnicity F(2, 229) = 3.12, p = .046, partial η2 = .027, with Latinos demonstrating significantly greater internal cIMT compared to NHB but not NHWs. In minimally adjusted models, there was a main effect for race/ethnicity, F(2, 227) = 3.10, p = .047, partial η2 = .027, with significantly greater internal cIMT in Latinos compared to NHBs but not NHWs. In fully adjusted models, racial/ethnic differences in cIMT were attenuated. Contrary to study hypotheses, no racial/ethnic differences in social support were found and social support was not a moderator of racial/ethnic differences in subclinical disease. In the North Texas Heart Study, few racial/ethnic differences emerged, with fully adjusted risk factor models accounting for these differences.
Date: August 2017
Creator: Garcia, James Jonathan
Partner: UNT Libraries

Laser Additive Manufacturing of Magnetic Materials

Description: A matrix of variably processed Fe-30at%Ni was deposited with variations in laser travel speeds as well and laser powers. A complete shift in phase stability occurred as a function of varying laser travel speed. At slow travel speeds, the microstructure was dominated by a columnar fcc phase. Intermediate travel speeds yielded a mixed microstructure comprised of both the columnar fcc and a martensite-like bcc phase. At the fastest travel speed, the microstructure was dominated by the bcc phase. This shift in phase stability subsequently affected the magnetic properties, specifically saturation magnetization. Ni-Fe-Mo and Ni-Fe-V permalloys were deposited from an elemental blend of powders as well. Both systems exhibited featureless microstructures dominated by an fcc phase. Magnetic measurements yielded saturation magnetizations on par with conventionally processed permalloys, however coercivities were significantly larger; this difference is attributed to microstructural defects that occur during the additive manufacturing process.
Date: August 2017
Creator: Mikler, Calvin
Partner: UNT Libraries

It's All Coming Back to You: 1980s Retro Film Culture and the Masculinity of Cult

Description: The 1980s is a formative decade in American history. America sought to reestablish itself as a global power and to reassert the dominant ideology of white, patriarchal capitalism. Likewise, media producers in the 1980s sought to reassert the dominance of the white, male, muscled body in filmic representations. The identity politics of the 1980s and the depictions of the white, muscled body once prominent in the 1980s have been the site of conservative nostalgia for a young, male-dominated, cult audience that is a subset of a larger cultural trend known as retro film culture. This thesis provides historical context behind the populist 1980s B-action films from Cannon Group, Inc that celebrate violent masculinity in filmic representations with white, male action heroes. Equally important is the revival of VHS collecting and how this 1980s-inspired subculture reinforces white, patriarchal capitalism through the cult films they valorize and their capitalistic trading practices despite their claims of oppositionality against mainstream taste and Hollywood films. Lastly, this thesis reveals how a new cycle of contemporary films primarily produced outside of Hollywood reasserts and celebrates the dominance of the white, male, muscled body in filmic representations despite a postmodern and hyperconscious exterior. Overall, I argue how these areas of nostalgia are distinct, yet not unrelated, because they reassert white, patriarchal capitalism through the revival of conservative nostalgia for the 1980s.
Date: August 2017
Creator: Collins, Ryan William
Partner: UNT Libraries

Investigating Human Gut Microbiome in Obesity with Machine Learning Methods

Description: Obesity is a common disease among all ages that has threatened human health and has become a global concern. Gut microbiota can affect human metabolism and thus may modulate obesity. Certain mixes of gut microbiota can protect the host to be healthy or predispose the host to obesity. Modern next-generation sequencing technique allows accessing huge amount of genetic information underlying microbiota and thus provides new insights into the functionality of these micro-organisms and their interactions with the host. Multiple previous studies have demonstrated that the microbiome might contribute to obesity by increasing dietary energy harvest, promoting fat deposition and triggering systemic inflammation. However, these researches are either based on lab cultivation studies or basic statistical analysis. In order to further explore how gut microbiota affect obesity, this thesis utilize a series of machine learning methods to analyze large amount of metagenomics data from human gut microbiome. The publicly available HMP (Human Microbiome Project) metagenomic sequencing data, contain microbiome data for healthy adults, including overweight and obese individuals, were used for this study. HMP gut data were organized based on two different feature definitions: taxonomic information and metabolic reconstruction information. Several widely used classification algorithms: namely Naive Bayes, Random Forest, SVM and elastic net logistic regression were applied to predict healthy or obese status of the subjects based on the cross-validation accuracy. Furthermore, the corresponding feature selection algorithms were used to identify signature features in each dataset that lead to the differences between healthy and obese samples. The results showed that these algorithms perform poorly on taxonomic data than metabolic pathway data though lots of selected taxa are still supported by literature. Among all the combinations between different algorithms and data, elastic net logistic regression has the best cross-validation performance and thus becomes the best model. In this model, several important ...
Date: August 2017
Creator: Zhong, Yuqing
Partner: UNT Libraries

Two-Phase Spray Cooling with HFC-134a and HFO-1234yf for Thermal Management of Automotive Power Electronics using Practical Enhanced Surfaces

Description: The objective of this research was to investigate the performance of two-phase spray cooling with HFC-134a and HFO-1234yf refrigerants using practical enhanced heat transfer surfaces. Results of the study were expected to provide a quantitative spray cooling performance comparison with working fluids representing the current and next-generation mobile air conditioning refrigerants, and demonstrate the feasibility of this approach as an alternative active cooling technology for the thermal management of high heat flux power electronics (i.e., IGBTs) in electric-drive vehicles. Potential benefits of two-phase spray cooling include achieving more efficient and reliable operation, as well as compact and lightweight system design that would lead to cost reduction. The experimental work involved testing of four different enhanced boiling surfaces in comparison to a plain reference surface, using a commercial pressure-atomizing spray nozzle at a range of liquid flow rates for each refrigerant to determine the spray cooling performance with respect to heat transfer coefficient (HTC) and critical heat flux (CHF). The heater surfaces were prepared using dual-stage electroplating, brush coating, sanding, and particle blasting, all featuring "practical" room temperature processes that do not require specialized equipment. Based on the obtained results, HFC-134a provided a better heat transfer performance through higher HTC and CHF values compared to HFO-1234yf at all tested surfaces and flow rates. While majority of the tested surfaces provided comparable HTC and modestly higher CHF values compared to the reference surface, one of the enhanced surfaces offered significant heat transfer enhancement.
Date: August 2017
Creator: Altalidi, Sulaiman Saleh
Partner: UNT Libraries

Crystallographic Complex Reflection Groups and the Braid Conjecture

Description: Crystallographic complex reflection groups are generated by reflections about affine hyperplanes in complex space and stabilize a full rank lattice. These analogs of affine Weyl groups have infinite order and were classified by V.L. Popov in 1982. The classical Braid theorem (first established by E. Artin and E. Brieskorn) asserts that the Artin group of a reflection group (finite or affine Weyl) gives the fundamental group of regular orbits. In other words, the fundamental group of the space with reflecting hyperplanes removed has a presentation mimicking that of the Coxeter presentation; one need only remove relations giving generators finite order. N.V Dung used a semi-cell construction to prove the Braid theorem for affine Weyl groups. Malle conjectured that the Braid theorem holds for all crystallographic complex reflection groups after constructing Coxeter-like reflection presentations. We show how to extend Dung's ideas to crystallographic complex reflection groups and then extend the Braid theorem to some groups in the infinite family [G(r,p,n)]. The proof requires a new classification of crystallographic groups in the infinite family that fail the Steinberg theorem.
Date: August 2017
Creator: Puente, Philip C
Partner: UNT Libraries

Using Possible Selves to Examine the Impact of Internalized Stigma of Mental Illness on the Career Development of College Students with Hidden Disability

Description: The purpose of the study was to examine the impact of internalized stigma of mental illness on the career development of college students with hidden disabilities. The availability of research investigating career variables within this population is limited and is primarily focused within the vocational rehabilitation arena. Therefore, one of the goals of the current study was to link separate bodies of literature on college students with disabilities, career development, and internalized stigma of mental illness. The second goal was to examine the interaction of internalized stigma of mental illness between career decision self-efficacy and career exploration on the perceived likelihood of achieving hoped for occupational possible selves (OPS). The study included college students with hidden disabilities and investigated variables related to mental illness and career. Participants were administered a background information questionnaire, the Career Decision Self-Efficacy scale (CDSE-SF), selected subscales of the Career Exploration Survey (CES), and the Internalized Stigma of Mental Illness scale (ISMI). Contrary to hypotheses, career decision making self-efficacy, career self-exploration, and internalized stigma of mental illness did not have a direct effect on the perceived likelihood of achieving hoped for OPS. However, career environment exploration did have a direct and positive association with perceived likelihood of achieving hoped for OPS. Results further indicated internalized stigma of mental illness did not moderate the effect of career decision self-efficacy and career exploration on the perceived likelihood of achieving one's hoped for occupational self. Study implications, limitations, and future directions are discussed.
Date: August 2017
Creator: Campbell, Robyn
Partner: UNT Libraries

Reproduction and Metabolic Responses to Acute and Chronic Hypoxia in Ovoviviparous Blaberid Cockroaches, with a Focus on Blaptica dubia

Description: The major components of the tracheal system of insects are an extension of the exoskeleton, and the size of the exoskeleton is fixed in the adult stage, so any increase in metabolic demand that may accompany reproduction must be met by a relatively unaltered tracheal system that the female set in place at ecdysis, when entering adulthood. Acute hypoxia tends to elicit an increase in ventilation in insects, and here, I observe increased interburst VCO2 release, and a tendency towards a more continuous gas exchange pattern being preferred over discontinuous gas exchange when Blaptica dubia and Eublaberus posticus are exposed to a descending regime of hypoxia. Additionally, higher temperatures appear to increase sensitivity to hypoxia in these species, an expected result because both species, like most ectothermic animals, display a Q10 effect, increasing metabolic rates as temperature increases. The reproductive mode of B. dubia is considered to be lecithotrophic pseudoviviparity (or type A ovoviviparity), and by the time the embryos are born, they have more than doubles in volume from the time of oviposition. This gain is apparent in the wet mass of the embryo, with no change occurring in dry mass. The egg mass that can be attributed to water begins at 39% at oviposition and increased to nearly 82% at hatching. The metabolic rates of females and embryos increase as embryonic development progresses, but bomb calorimetry reveals that energy content of the embryos does not change. It is possible that these embryos gain some nutrition from the mother during embryonic development, but direct evidence remains to be demonstrated. Blaptica dubia and Eublaberus posticusare both blaberid species that display the same reproductive mode, pseudoviviparity, with incubation occurring in a brood sac. Comparisons between the reproductive traits of B. dubia and E. posticus reveal that the two species have similar ...
Date: August 2017
Creator: Mallery, Christopher Sean
Partner: UNT Libraries

The Impact of Observational Learning on Physical Activity Appraisal and Exertion Following Experimental Back Injury and the Role of Pain-Related Fear

Description: Chronic low back pain (CLBP) is one of the most prevalent and disabling health conditions in the US and worldwide. Biomedical explanations of acute injury fail to account for why some individuals experience remission of pain and restoration of physical function while others do not. Pain-related fear, accompanied by elevated appraisals of physical exertion and avoidance of physical activity, has emerged as a central psychosocial risk factor for transition from acute injury to chronic pain and disability. Research has indicated that these pain-related factors may be maintained through observational learning mechanisms. To date, no studies have experimentally examined the role of observational learning and pain-related fear in the context of actual musculoskeletal injury. Accordingly, the present study examined the impact of observational learning and pain-related fear on activity appraisals and exertion following experimentally- induced acute low back injury. Healthy participants' appraisal of standardized movement tasks along with measures of physical exertion were collected prior to and following a procedure designed to induce delayed onset muscle soreness (DOMS) to the lower back. Following induction of DOMS, participants observed a video prime depicting CLBP patients exhibiting either high or low pain behavior during similar standardized movements. In line with hypothesized effects, participants assigned to the high pain behavior prime demonstrated greater elevation in pain and harm appraisals as well as greater decrement in physical exertion. Further in line with hypotheses, significant changes in appraisal and physical performance following the high pain behavior prime were only observed among participants endorsing high pain-related fear during baseline assessment. Discussion of findings addresses potential mechanisms of action as well as study limitations and direction for future research.
Date: August 2017
Creator: Guck, Adam
Partner: UNT Libraries