UNT Libraries - 17,850 Matching Results

Search Results

Note: All results matching your query require you to be a member of the UNT Community (you must be on campus or login with university credentials for access).

The Relationship between Teacher Attrition and Student Achievement in Reading among Middle School Students

Description: The purpose of this study was to determine whether a significant relationship existed between teacher attrition and student success in middle school reading by conducting a quantitative analysis. Additionally, the inclusion of school demographic characteristics were included in the model to consider previous findings referencing the challenges schools face in attracting and retaining teachers in low performing urban schools with high populations of economically disadvantaged and minority students. In this analysis, the relationship between teacher attrition and student achievement in middle school as measured by the State of Texas Assessments of Academic Readiness (STAAR) for reading among middle school students in Grades 6, 7, and 8, as reported on the Texas Academic Performance Reports (TAPR), were examined. The regression models used to analyze the three research questions addressed in the study include an examination of teacher attrition on campus pass rates, and grade level pass rates for sixth, seventh, and eighth grades as measured by the STAAR Reading assessment. The data utilized in this study were collected from seven North Texas middle schools in a fast growth school district together with their comparable campuses as identified by the Texas Education Agency for the school years 2013-2014 through 2015-2016. The results of the analysis indicate teacher attrition accounts for a significant variance in STAAR Reading pass rates among middle school students. Additionally, the school demographic characteristics defined as percentage economically disadvantaged, percentage English language learners, mobility rates, and percentage white students account for 83.4% of the variance in the average campus pass rates for STAAR Reading when combined.
Date: August 2017
Creator: Perkins, Gwendolyn Moseley

Kinetic Study of the Reactions of Chlorine Atoms with Fluoromethane and Fluoromethane-d3 in the Gas Phase

Description: The kinetics of the gas-phase reactions of chlorine atoms with fluoromethane (CH3F) and fluoromethane-d3(CD3F) were tested experimentally. The relative rate method was applied by using CH4 as the reference compound for fluoromethane (CH3F) and CH4 and CH3F as the reference compound for fluoromethane-d3(CD3F). The rate constants for H-abstraction from CH3F and D-abstraction from CD3F were measured at room temperature and a total pressure of 920 Torr using Ar as a diluent. The rate constants are described by the expressions: kH= (3.50±0.52) x 10-13 cm3 molecule-1 s-1 and kD=(5.0±0.51) x 10-14 cm3 molecule-1 s-1. The kinetic isotope effect, equal to the ratio kH/kD, was found to be 7.0±1.2 at room temperature.
Date: August 2017
Creator: Shao, Kejun

Development and Analysis of a Mobile Node Tracking Antenna Control System

Description: A wireless communication system allows two parties to exchange information over long distances. The antenna is the component of a wireless communication system that allows information to be converted into electromagnetic radiation that propagates through the air. A system using an antenna with a highly directional beam pattern allows for high power transmission and reception of data. For a directional antenna to serve its purpose, it must be accurately pointed at the object it is communicating with. To communicate with a mobile node, knowledge of the mobile node's position must be gained so the directional antenna can be regularly pointed toward the moving target. The Global Positioning System (GPS) provides an accurate source of three-dimensional position information for the mobile node. This thesis develops an antenna control station that uses GPS information to track a mobile node and point a directional antenna toward the mobile node. Analysis of the subsystems used and integrated system test results are provided to assess the viability of the antenna control station.
Date: August 2017
Creator: Hensley, Phillip Hayden

The Impact of Commuting on Mental Health

Description: The purpose of this research is to explicate the relationship between commuting behavior, stress, and mental health. The overall results from the regression analysis turned out to be inconclusive given the researcher's initial hypothesis. The commute time reported by respondents did not have a statistically significant bearing on mental health outcomes. This was true for both the normal sample, and the sample that was split by gender.
Date: August 2017
Creator: Malek-Ahmadi, John H.

MBE Growth and Characterization of Graphene on Well-Defined Cobalt Oxide Surfaces: Graphene Spintronics without Spin Injection

Description: The direct growth of graphene by scalable methods on magnetic insulators is important for industrial development of graphene-based spintronic devices, and a route towards substrate-induced spin polarization in graphene without spin injection. X-ray photoelectron spectroscopy (XPS), low energy electron diffraction LEED, electron energy loss spectroscopy (EELS) and Auger electron spectroscopy (AES) demonstrate the growth of Co3O4(111) and CoO(111) to thicknesses greater than 100 Å on Ru(0001) surfaces, by molecular beam epitaxy (MBE). The results obtained show that the formation of the different cobalt oxide phases is O2 partial pressure dependent under same temperature and vacuum conditions and that the films are stoichiometric. Electrical I-V measurement of the Co3O4(111) show characteristic hysteresis indicative of resistive switching and thus suitable for advanced device applications. In addition, the growth of Co0.5Fe0.5O(111) was also achieved by MBE and these films were observed to be OH-stabilized. C MBE yielded azimuthally oriented few layer graphene on the OH-terminated CoO(111), Co0.5Fe0.5O(111) and Co3O4(111). AES confirms the growth of (111)-ordered sp2 C layers. EELS data demonstrate significant graphene-to-oxide charge transfer with Raman spectroscopy showing the formation of a graphene-oxide buffer layer, in excellent agreement with previous theoretical predictions. XPS data show the formation of C-O covalent bonding between the oxide layer and the first monolayer (ML) of C. LEED data reveal that the graphene overlayers on all substrates exhibit C3V. The reduction of graphene symmetry to C3V – correlated with C-O bond formation – enables spin-orbit coupling in graphene. Consequences may include a significant band gap and room temperature spin Hall effect – important for spintronic device applications. The results suggest a general pattern of graphene/graphene oxide growth and symmetry lowering for graphene formation on the (111) surfaces of rocksalt-structured oxides.
Date: August 2017
Creator: Olanipekun, Opeyemi B

Assessment of Competencies among Doctoral Trainees in Psychology

Description: The recent shift to a culture of competence has permeated several areas of professional psychology, including competency identification, competency-based education training, and competency assessment. A competency framework has also been applied to various programs and specialty areas within psychology, such as clinical, counseling, clinical health, school, cultural diversity, neuro-, gero-, child, and pediatric psychology. Despite the spread of competency focus throughout psychology, few standardized measures of competency assessment have been developed. To the authors' knowledge, only four published studies on measures of competency assessment in psychology currently exist. While these measures demonstrate significant steps in progressing the assessment of confidence, three of these measures were designed for use with individual programs, two of these international (i.e., UK and Taiwan). The current study applied the seminal Competency Benchmarks, via a recently adapted benchmarks form (i.e., Practicum Evaluation form; PEF), to practicum students at the University of North Texas. In addition to traditional supervisor ratings, the present study also involved self-, peer supervisor, and peer supervisee ratings to provide 360-degree evaluations. Item-response theory (IRT) was used to evaluate the psychometric properties of the PEF and inform potential revisions of this form. Supervisor ratings of competency were found to fit the Rasch model specified, lending support to use of the benchmarks framework as assessed by this form. Self- and peer-ratings were significantly correlated with supervisor ratings, indicating that there may be some utility to 360-degree evaluations. Finally, as predicted, foundational competencies were rated as significantly higher than functional competencies, and competencies improved significantly with training. Results of the current study provide clarity about the utility of the PEF and inform our understanding of practicum-level competencies.
Date: August 2017
Creator: Price, Samantha

Development of a Natural Fiber Mat Plywood Composite

Description: Natural fibers like kenaf, hemp, flax and sisal fiber are becoming alternatives to conventional petroleum fibers for many applications. One such applications is the use of Non-woven bio-fiber mats in the automobile and construction industries. Non-woven hemp fiber mats were used to manufacture plywood in order to optimize the plywood structure. Hemp fiber mats possess strong mechanical properties that comparable to synthetic fibers which include tensile strength and tensile modulus. This study focuses on the use of hemp fiber mat as a core layer in plywood sandwich composite. The optimization of fiber mat plywood was done by performing a three factor experiment. The three factors selected for this experiment were number of hemp mat layers in the core, mat treatment of the hemp mat, and the glue content in the core. From the analysis of all treatments it was determined that single hemp mat had the highest effect on improving the properties of the plywood structure.
Date: August 2017
Creator: Anthireddy, Prasanna Kumar

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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