Sexual Orientation and the Advanced Placement Art History Survey (open access)

Sexual Orientation and the Advanced Placement Art History Survey

This two-part study included a content analysis of an AP art history text and a survey together with interviews with AP art history teachers that embraced both quantitative and qualitative research methodologies. The first phase of the study examined one of the more popular art history survey texts in the AP art history program, Gardner’s Art through the Ages, in terms of how inclusive it is in addressing issues of sexual orientation and, particularly, same-sex perspectives. In addition, the text was examined for evidence of sexual orientation ignored – particularly same-sex perspectives ignored and for heteronormative hegemonies. The second phase investigated the understandings and opinions of AP art history teachers toward the inclusion of sexual orientation and same-sex perspectives in their curriculums and classrooms. Recent recognition of gay, lesbian, and same-sex perspectives in the study of art history has challenged art educators and art historians to begin to consider opening up their curriculums and writings to include these perspectives. These ignored perspectives produce important understandings that enrich and deepen the discourse of art history. The inclusion of gay and lesbian content and same-sex perspectives to the study of AP art history, not only effectively serves the needs of AP art …
Date: December 2014
Creator: Bond, Richard P.
System: The UNT Digital Library
A Feasibility Study of Cellular Communication and Control of Unmanned Aerial Vehicles (open access)

A Feasibility Study of Cellular Communication and Control of Unmanned Aerial Vehicles

Consumer drones have used both standards such as Wi-Fi as well as proprietary communication protocols, such as DJI's OcuSync. While these methods are well suited to certain flying scenarios, they are limited in range to around 4.3 miles. Government and military unmanned aerial vehicles (UAVs) controlled through satellites allow for a global reach in a low-latency environment. To address the range issue of commercial UAVs, this thesis investigates using standardized cellular technologies for command and control of UAV systems. The thesis is divided into five chapters: Chapter 1 is the introduction to the thesis. Chapter 2 describes the equipment used as well as the test setup. This includes the drone used, the cellular module used, the microcontroller used, and a description of the software written to collect the data. Chapter 3 describes the data collection goals, as well as locations in the sky that were flown in order to gather experimental data. Finally, the results are presented in Chapter 4, which draws limited correlation between the collected data and flight readiness Chapter 5 wraps up the thesis with a conclusion and future areas for research are also presented.
Date: December 2019
Creator: Gardner, Michael Alan
System: The UNT Digital Library
Johannes Brahms's Ein deutsches Requiem: A Comparison of the Reduced Orchestration Techniques in Joachim Linckelmann's Chamber Ensemble Version to Brahms's Four-Hand Piano Version (open access)

Johannes Brahms's Ein deutsches Requiem: A Comparison of the Reduced Orchestration Techniques in Joachim Linckelmann's Chamber Ensemble Version to Brahms's Four-Hand Piano Version

Recognizing the challenges small groups have to program a major work, in 2010, Joachim Linckelmann created a chamber ensemble arrangement of Johannes Brahms's "Ein deutsches Requiem." In 1869, J.M. Reiter-Biedermann published Brahms's four-hand piano arrangement of "Ein deutsches Requiem." Brahms's arrangement serves as an excellent comparison to the chamber ensemble version by Linckelmann, since it can be assumed that Brahms chose to highlight and focus on the parts he deemed the most important. This study was a comparative analysis of the two arrangements and was completed in three stages. The first stage documented every significant change in Joachim Linckelmann's recent chamber arrangement. The second stage classified each change as either a reduction, reorganization, or elimination. The final stage of the analysis was to compare the choices made by Linckelmann to those made by Brahms. The results show that Linckelmann's choices for reduction, reorganization, and elimination closely align with those of Brahms. The only differences between the arrangements can be attributed to Linckelmann's focus on retaining the original orchestral timbre and Brahms's focus on providing the original vocal parts.
Date: December 2016
Creator: Hawley, Aaron (Michael Aaron)
System: The UNT Digital Library
An Exploratory Study of the Impact of Institutional Policies and Practices of Community and Technical Colleges in Texas on Student Persistence in Online Courses (open access)

An Exploratory Study of the Impact of Institutional Policies and Practices of Community and Technical Colleges in Texas on Student Persistence in Online Courses

Online education is the fastest growing form of course delivery of higher education in the United States. It has revolutionized how students and instructors interact in the educational process. Yet students in online courses continue to experience higher attrition rates than their counterparts in traditional face-to-face classes despite the advantages offered by the technology. This study examined the impact that institutional policies and practices at community colleges in the state of Texas have had on student persistence in online courses. It also examined how institutions collect and use data in addressing students' attrition. The findings were used to identify the most effective institutional practices to share with community college systems in Texas in an effort to improve student persistence in online courses across the state. The population for the study consisted of the 50 public two-year community college and the technical college systems in the state of Texas. The study used a mixed method. A theoretical model of institutional impact on online persistence was drawn from the literature review. This model's five categories were then used to construct a survey to collect data on institutional practices and measure the effectiveness in addressing student persistence. Four college systems were identified using …
Date: December 2010
Creator: Hills, Fred W.
System: The UNT Digital Library
As the Need Presents Itself: Social Identity Theory and Signaling in Online Crowdfunding Campaigns (open access)

As the Need Presents Itself: Social Identity Theory and Signaling in Online Crowdfunding Campaigns

As social interactions increasingly become exclusively online, there is a need for research on the role of identity and social identity in online platforms. Drawing on Symbolic Interactionist approaches to identity, namely Social Identity Theory and Identity Theory, as well as Signaling Theory, this study argues that actors will selectively use religious language to signal their credentials to an audience for the purpose of garnering prosocial behavior in the form of donations to their fundraising campaign. Using latent semantic analysis topic models to analyze the self-presentations of crowdsourcing campaigners on GoFundMe.com, this study found evidence for the presence of signaling to a religious identity online as well as a significant difference in the presentation of need for campaigns originating in areas with high reported religiosity compared to campaigns from areas of low religiosity. In comparison to other campaigns, campaigners engaging in religious signaling were significantly increasing their donations. I suggest that strategically chosen religious topics in online crowdfunding is an example of low-cost identity signaling and provides insight into how signaling happens online and the potential outcomes resulting from this cultural work.
Date: December 2019
Creator: Hamilton, Scott J
System: The UNT Digital Library
African-American Achievement in Charter Schools and the Impact of Connectedness, Alignment, Rigor, and Engagement (C.A.R.E.) on School Effectiveness: A Meta-Analysis and Systematic Review (open access)

African-American Achievement in Charter Schools and the Impact of Connectedness, Alignment, Rigor, and Engagement (C.A.R.E.) on School Effectiveness: A Meta-Analysis and Systematic Review

The purpose of the study was to examine the effects of charter schools on African-American students, this study sought to determine if the practice of connectedness, alignment, rigor, and engagement (C.A.R.E.) influenced academic outcomes. The research methodology employed a meta-analysis in conjunction with a systematic review as a cross-reference and to address variables not covered in the meta-analysis. Utilizing a meta-analysis allowed for a synthesis of the existing quantitative published data to consolidate the results. This produced a specific report of achievement data for African-American students. The results revealed that regardless of region, subject, type of assessment, or school focus charter school do positively influence African-American students' academic outcomes. This study also found the practices connectedness, alignment, rigor, and engagement, the C.A.R.E. model when employed in schools improve academic outcomes, especially when combined and implemented with best practices.
Date: December 2018
Creator: McCloud, Margie J
System: The UNT Digital Library
Fashion-brand Experiences in Multi-channel Retailing: Impacts of Experience Dimensions and Experience Types on Brand Resonance (open access)

Fashion-brand Experiences in Multi-channel Retailing: Impacts of Experience Dimensions and Experience Types on Brand Resonance

The brand behind the garment is what gives the product popularity, relevance to the consumer, and overall profitability. As time passes, markets are becoming flooded with more brands that inherently provide the commodities. As a result, fashion marketers must put more time and investment into stipulating ways for which their brand can reach a select target consumer and enhance repeat purchase intentions with their competitive differentiations. As their efforts engage, an experiential perspective emerges in the fashion industry. By comparing fashion brands and their different distribution channels, the objectives of this study are to identify consumers’ perceptions of fashion brand experience dimensions and experience types, and to investigate the effect of brand experience dimensions and types on brand resonance. Upon extending Schmitt and Brakus, Schmitt, and Zarantonello’s experience dimensions and types, in conjunction with Keller’s brand resonance model, 12 out of 20 hypotheses confirm the significant impact of consumers experiences on brand resonance by analyzing the data (n = 374) from a university in the United States. Sensory and affective experiences are primary factors for establishing fashion brand association, while cognitive and relational driven experiences lead to establishing fashion brand loyalty. Sensory, affective, and relational experiences affect both product and …
Date: December 2011
Creator: Evans, Leslie J.
System: The UNT Digital Library
Students' Attitudes Towards Rapport-building Traits and Practices in Online Learning Environments (open access)

Students' Attitudes Towards Rapport-building Traits and Practices in Online Learning Environments

This research was a triangulated study of student attitudes towards instructors' rapport-building traits and their preferences amongst instructors' rapport-building practices in online learning environments. Participants were undergraduate and graduate students enrolled in courses within an educational technology program at a central Texas university. The study employed a mixed-methods approach involving the Likert-item assessment of learners' attitudes, the identification and prioritization of learner preferences through pairwise comparisons, and semi-structured interviews that provided richer, more detailed information. Findings indicated a strong preference for instructor-based traits and practices over pedagogically-based ones. These traits and practices loaded into the components of social presence, enjoyable interaction, and personal connection.
Date: December 2012
Creator: Wright, Robert Demmon
System: The UNT Digital Library
Relationship Centrality and Expressive Writing: Understanding Post-breakup Distress (open access)

Relationship Centrality and Expressive Writing: Understanding Post-breakup Distress

When a romantic relationship ends in dissolution, the ex-partners may experience distress similar to post-traumatic stress or complex grief (i.e., dysphoric mood, feelings of loss, intrusive memories, negative rumination regarding the relationship, and a loss of self-esteem). Interventions designed to reduce post-breakup distress have historically attempted to foster integration of the breakup into the self-narrative through techniques such as expressive writing. Recent research indicates centrality, or heightened integration of an event or concept into an individual’s identity, predicts heightened levels of distress in the case of negative life events, including romantic relationship dissolution. Given the role romantic relationships themselves play in identity formation, exploration is warranted of the potential distress resulting from over-identification with a romantic relationship itself, or relationship centrality, after a breakup has occurred. Furthermore, if an individual has overly-integrated a relationship into their identity, the effectiveness of interventions focusing on further integration of the breakup is called into question. This study explored the centrality of participants’ previous romantic relationships, the distress resulting from the dissolution of those relationships, and the role of expressive writing as a distress reduction tool when centrality is taken into account.
Date: December 2015
Creator: Nowlin, Rachel B.
System: The UNT Digital Library
Endocannabinoid System in a Planarian Model (open access)

Endocannabinoid System in a Planarian Model

In this study, the presence and possible function of endocannabinoid ligands in the planarian is investigated. The endocannabinoids ananadamide (AEA) and 2-arachidonoylglycerol (2-AG) and entourage NAE compounds palmitoylethanolamide (PEA), stearoylethanolamide (SEA) and oleoylethanolamide (OEA) were found in Dugesia dorotocephala. Changes in SEA, PEA, and AEA levels were observed over the initial twelve hours of active regeneration. Exogenously applied AEA, 2-AG and their catabolic inhibition effected biphasic changes in locomotor velocity, analogous to those observed in murines. The genome of a close relative, Schmidtea mediterranea, courtesy of the University of Utah S. med genome database, was explored for cannabinoid receptors, none were found. A putative fatty acid amide hydrolase (FAAH) homolog was found in Schmidtea mediterranea.
Date: December 2010
Creator: Mustonen, Katie Lynn
System: The UNT Digital Library
Retention: Course Completion Rates in Online Distance Learning (open access)

Retention: Course Completion Rates in Online Distance Learning

Online courses in higher education have a reputation for having a lower course completion or retention rate than face-to-face courses. Much of this reputation is based upon anecdotal evidence, is outdated, or is on a small scale, such as a comparison of individual courses or programs of instruction. A causal-comparative analysis was conducted among 11 large, high research public universities. The universities were compared to each other to determine if differences existed between online and face-to-face course completion; undergraduate and graduation online course completion was analyzed for differences as well. The findings suggested the magnitude of the differences between online and face-to-face completions rates was small or negligible. The area which showed a higher magnitude of difference was in the comparison between undergraduate and graduate online course completion; the practical significance could be worth considering for educational purposes.
Date: December 2015
Creator: Phillips, Alana S.
System: The UNT Digital Library
Using Relational Responding to Examine the Acquisition of Mindfulness and Meditation Material: An Analogue Study (open access)

Using Relational Responding to Examine the Acquisition of Mindfulness and Meditation Material: An Analogue Study

Mindfulness meditation is a growing area of interest for both mental health professionals and the general public alike. Beneficial outcomes are associated with these practices, although the variety of measurement techniques makes research difficult to interpret. Definitions of these constructs are varied, and anecdotal accounts point to the idea that many people hold misconceptions about mindfulness and meditation, even when meanings are made clear. Still, no formal research has been published on misconceptions of mindfulness – or, if they exist, how such misinformation affects acquisition of related skills. Furthermore, mindfulness has been incorporated into therapeutic modalities without much consideration for context, including the client's learning history. The current analogue study examined how the presentation of mindfulness meditations (i.e., inaccurate rationale/meditation and accurate rationale/meditation) affects an individual's practice. Specifically, self-reported mindfulness and meditation skills, mood questionnaires, a matching-to-sample task, and qualitative measurements were used to assess acquisition. Although primary hypotheses did not yield significant findings, results from both preliminary and exploratory analyses demonstrate significant findings with regard to teaching, learning, and measurement related to mindfulness meditation. The results, future directions, and limitations are discussed.
Date: December 2016
Creator: Lester, Ethan G.
System: The UNT Digital Library
A Case Study of Leadership Supports of Job-Embedded Professional Development (open access)

A Case Study of Leadership Supports of Job-Embedded Professional Development

Professional development is a critical part of school improvement and enhancing teacher quality; yet there is limited literature about how principals design and lead effective professional development systems. The research activities in this qualitative single case study explored the leadership practices at one successful school implementing job-embedded professional development. A conceptual framework relating Hallinger's leadership for learning construct to professional development helped frame the research. Collected data included participant interviews, a focus group interview, observations, and relevant document analysis. These data were analyzed using a general inductive method to identify the prevailing leadership characteristics. The major themes that emerged during analysis were: (a) vision and goals, (b) high expectations, (c) structures and resources, (d) communication, (e) monitoring progress and providing recognition, (f) focused and ongoing professional development, (g) differentiated professional development, (h) trust and professionalism, (i) culture of learning and growth, (j) building capacity, and (k) collaboration. These themes aligned well with the initial conceptual framework. These findings support the concept that leadership for learning may have implications for school leaders trying to implement effective job-embedded professional development.
Date: December 2019
Creator: Jones, Amber
System: The UNT Digital Library
Finding a Data-Driven Definition of Binge-Watching (open access)

Finding a Data-Driven Definition of Binge-Watching

Binge-watching, the act of watching large amounts of television at a time, has become a popular phenomenon internationally; however, it has yet to be sufficiently defined. In order to define binge-watching, data was collected on specific watching instances from 216 undergraduate students at a large research university. Hierarchical and k-means cluster analyses were conducted in Phase I to empirically determine how binge-watching should be defined. In Phase II, that definition was tested by correlating the number of instances of binge-watching in a one-week period, collected by seven days of daily diary logs, with several theoretically related measures including body mass index, dissociative tendencies, psychological distress, compulsion to watch, boredom proneness, and escapism through watching. The data-driven definition was found to be that eight hours or more of continuous watching was binge-watching, while anything less than that was not. In Phase II, the frequency of binge-watching through the seven-day period was calculated based on that new definition. The frequency of binge-watching was positively correlated with body mass index and dissociative tendencies with statistical significance at the alpha = .05 level. Compulsion to watch was not statistically significant; however, there was a positive correlation. These findings indicate that the proposed data-driven definition …
Date: December 2019
Creator: Kelly, Megan Erin
System: The UNT Digital Library
Exploring the Effectiveness of Curriculum Provided Through Transmedia Books for Increasing Students’ Knowledge and Interest in Science (open access)

Exploring the Effectiveness of Curriculum Provided Through Transmedia Books for Increasing Students’ Knowledge and Interest in Science

Transmedia books are new and emerging technologies which are beginning to be used in current classrooms. Transmedia books are a traditional printed book that uses multiple media though the use of Quick Response (QR) codes and augmented reality (AR) triggers to access web-based technology. Using the transmedia book Skills That Engage Me students in kindergarten through second grade engage in curriculum designed to introduce science skills and careers. Using the modified Draw-a-Scientist Test (mDAST), observations and interviews, researchers analyzed pre and post data to describe changes students have about science and scientists. Future study may include the development and validation of a new instrument, Draw a Science Student, and examining the mDAST checklist with the intention of updating the parameters of what is considered positive and negative in relationship with work a scientist conducts.
Date: December 2015
Creator: Ponners, Pamela Jones
System: The UNT Digital Library
Josephus’ Jewish War and the Causes of the Jewish Revolt: Re-examining Inevitability (open access)

Josephus’ Jewish War and the Causes of the Jewish Revolt: Re-examining Inevitability

The Jewish revolt against the Romans in 66 CE can be seen as the culmination of years of oppression at the hands of their Roman overlords. The first-century historian Josephus narrates the developments of the war and the events prior. A member of the priestly class and a general in the war, Josephus provides us a detailed account that has long troubled historians. This book was an attempt by Josephus to explain the nature of the war to his primary audience of predominantly angry and grieving Jews. The causes of the war are explained in different terms, ranging from Roman provincial administration, Jewish apocalypticism, and Jewish internal struggles. The Jews eventually reached a tipping point and engaged the Romans in open revolt. Josephus was adamant that the origin of the revolt remained with a few, youthful individuals who were able to persuade the country to rebel. This thesis emphasizes the causes of the war as Josephus saw them and how they are reflected both within The Jewish War and the later work Jewish Antiquities. By observing the Roman provincial administration spanning 6-66 CE, I argue that Judaea had low moments sprinkled throughout the time but in 66 there was something …
Date: December 2013
Creator: Lopez, Javier
System: The UNT Digital Library
Photo-induced Toxicity of Deepwater Horizon Spill Oil to Four Native Gulf of Mexico Species (open access)

Photo-induced Toxicity of Deepwater Horizon Spill Oil to Four Native Gulf of Mexico Species

The 2010 Deepwater Horizon oil spill resulted in the accidental release of millions of barrels of crude oil into the Gulf of Mexico (GoM). Photo-induced toxicity following co-exposure to ultraviolet (UV) radiation is one mechanism by which polycyclic aromatic hydrocarbons (PAHs) from oil spills may exert toxicity. Blue crab (Callinectes sapidus) are an important commercial and ecological resource in the Gulf of Mexico and their largely transparent larvae may make them sensitive to PAH photo-induced toxicity. Mahi-mahi (Coryphaena hippurus), an important fishery resource, have positively buoyant, transparent eggs. These characteristics may result in mahi-mahi embryos being at particular risk from photo-induced toxicity. Red drum (Sciaenops ocellatus) and speckled seatrout (Cynoscion nebulosus) are both important fishery resources in the GoM. They spawn near-shore and produce positively buoyant embryos that hatch into larvae in about 24 h. The goal of this body of work was to determine whether exposure to UV as natural sunlight enhances the toxicity of crude oil to early lifestage GoM species. Larval and embryonic organisms were exposed to several dilutions of water accommodated fractions (WAF) from several different oils collected in the field under chain of custody during the 2010 spill and two to three gradations of natural …
Date: December 2015
Creator: Alloy, Matthew Michael
System: The UNT Digital Library
In-service Teacher Perception of Feedback From Formative Evaluation Within the Teacher Appraisal Process and Its Relationship to Teacher Self-efficacy (open access)

In-service Teacher Perception of Feedback From Formative Evaluation Within the Teacher Appraisal Process and Its Relationship to Teacher Self-efficacy

The purpose of the study is to describe the current status of and the relationships between teacher self-efficacy and in-service teachers’ perceptions and/or attitudes of (a) the quantity and quality of feedback from formative evaluation, (b) toward feedback from formative evaluation, and (c) the impact of feedback from formative evaluation on teacher self-efficacy. In addition to calculating correlation coefficients, 6 teachers were interviewed – 2 each from high, medium, and low efficacy schools. The quantitative data reported low, positive correlations between all of the factors. Statistically significant correlations were found between 8 of the 12 factors including teacher attitudes toward feedback from formative evaluation and: overall Teacher Sense of Efficacy Scale (r = .302), student engagement (r = .309), instructional strategies (r = .237) and classroom management (r =.266). Other statistically significant correlations were found between teacher perceptions of the impact of feedback from formative evaluation and its relationship to self-efficacy and: overall Teachers’ Sense of Efficacy Scale (r = .295), Student Engagement (r = .300), Instructional Strategies (r = .209), and Classroom Management (r = .282). The face-to-face interviews and online focus group supported the quantitative findings as the participants reported that they value formative evaluation and feedback and …
Date: December 2014
Creator: Curran, Chaney L.
System: The UNT Digital Library
Teacher Perceptions of Student Engagement as Related to Technology Implementation in the Classroom (open access)

Teacher Perceptions of Student Engagement as Related to Technology Implementation in the Classroom

The challenges of at-risk students are not new. Newspaper articles from the 1860s presented information about communities seeking to help students to complete school and find employment to provide a livable wage. Today's solutions focus on legislation intended to affect societal change and provide equitable opportunities for at-risk students. Much research regarding how to improve academic outcomes for at-risk students addresses high school level, identifying those factors that encourage secondary learners to remain in school. However, less work has been done investigating whether earlier intervention can obviate later retention efforts by improving students' learning outcomes in the elementary grades. In this vein, engagement is a factor found to positively influence learning, particularly when students are actively engaged with instructional content. Technology can facilitate such interactions between students and content; however, research is needed to better understand the relationship between student engagement and technology, particularly with at-risk students in elementary settings. Seeking to address the gap, this qualitative study examined the occasion of a fifth-grade school that recently implemented 1:1 technology. Using a case study approach, researchers explored the effects of the 1:1 Chromebook implementation on teacher-perceived student engagement at the elementary level. This study sought to better understand how this …
Date: December 2018
Creator: Mata, Jodi Lane
System: The UNT Digital Library
Effects of a Water Conservation Education Program on Water Use in Single-family Homes in Dallas, Texas (open access)

Effects of a Water Conservation Education Program on Water Use in Single-family Homes in Dallas, Texas

The City of Dallas Environmental Education Initiative (EEI) is a hands-on, inquiry-based, K-12 water conservation education program that teaches students concepts about water and specific water conservation behaviors. Few descriptions and evaluations, especially quantitative in nature, of water conservation education programs have previously been conducted in the literature. This research measured the quantitative effects and impacts of the education program on water use in single-family homes in Dallas, Texas. A total of 2,122 students in 104 classrooms at three schools in the Dallas Independent School District received hands-on, inquiry-based water conservation education lessons and the average monthly water use (in gallons) in single-family homes was analyzed to measure whether or not there was a change in water use. The results showed that over a period of one calendar year the water use in the single-family homes within each school zone and throughout the entire research area in this study experienced a statistically significant decrease in water use of approximately 501 gallons per home per month (independent, t-test, p>0.001). Data from this research suggests that EEI is playing a role in decreasing the amount of water used for residential purposes. Additionally, this research demonstrates the use of a quantitative tool by …
Date: December 2014
Creator: Serna, Victoria Faubion
System: The UNT Digital Library
Beta-adrenergic Blockade Via Atenolol and Its Effects on Blood Pressure, Heart Rate, and Renal Morphology in the Developing Chicken Gallus Gallus Domesticus (open access)

Beta-adrenergic Blockade Via Atenolol and Its Effects on Blood Pressure, Heart Rate, and Renal Morphology in the Developing Chicken Gallus Gallus Domesticus

Chicken embryos were chronically exposed to the ?1- blocker atenolol during one of three stages: mesonephros (E7-E9), mesonephros-metanephros (E11-E13), or metanephros (E15-E17). Mesonephros group hearts were larger than all other groups (P < 0.01). Mesonephros and metanephros group kidneys were larger than all remaining groups (P < 0.0001). The mesonephros group nephron number was ~40% lower than control values (P = 0.002). Glomerular areas were 26% and 18% larger than the control group in the mesonephros and metanephros groups, respectively (P < 0.001). These data suggest an E7-E9 critical window of cardiovascular and renal development for atenolol. Acute atenolol exposure in E15 embryos showed an increase in mean arterial pressure with all but the highest dose. All doses significantly decreased heart rate.
Date: December 2012
Creator: Rossitto Lopez, Josie Jovita
System: The UNT Digital Library
Transgenerational Responses to Environmental Stressors in Vertebrates: From Organisms to Molecules (open access)

Transgenerational Responses to Environmental Stressors in Vertebrates: From Organisms to Molecules

Genomic modifications occur slowly across generations, whereas short-term epigenetic transgenerational inheritance of adaptive phenotypes may be immediately beneficial to large numbers of individuals, acting as a bridge for survival when adverse environments occur. In this study we used dietary exposure to crude oil as an example of an environmental stressor to assess its effects from the molecular to the organismal levels in piscine and avian animal models. In addition, we assessed the role of the parental exposures on their offspring F1 generation. The research developed in this dissertation has contributed to several areas of investigation including molecular biology, animal physiology, and evolutionary biology. The quantitative information from these studies may be utilized to supplement information regarding the proximate and ultimate effects of environmental stressors on fish and bird populations. Furthermore, this information may be used as additional support for understanding the conservation of the responses from the molecular to the whole organismal levels across the vertebrate taxa, as well as their implications for population survival and maintenance. Additionally, the zebrafish (Danio rerio), the Siamese fighting fish (Betta splendens) and the king quail (Coturnix chinensis) have proven to be excellent models to start building a strong basis for understanding the effects …
Date: December 2019
Creator: Martinez Bautista, Naim
System: The UNT Digital Library
The Impact of Developmental Stress on Cardiovascular Physiology of Two Archosaur Species: American Alligator (Alligator mississippiensis) and Domestic Chicken (Gallus gallus) (open access)

The Impact of Developmental Stress on Cardiovascular Physiology of Two Archosaur Species: American Alligator (Alligator mississippiensis) and Domestic Chicken (Gallus gallus)

Crocodilians and birds comprise sister taxa of archosaurs, the development of these vertebrates occurs within an egg case that leaves developing embryos susceptible to fluctuations in the nesting environment. Studies suggest that sub-optimal conditions alter morphological growth and cardiovascular physiology. Regulation of the cardiovascular system is immature in the subjects studied, and embryos may rely on humoral rather than neural control of the cardiovascular system. The primary focus of this dissertation was to assess regulatory mechanisms responsible for maintenance of arterial pressure and heart rate. Dehydration stress had marked effects on embryo growth, and altered baseline cardiovascular parameters, while leaving the response to humoral regulator, angiotensin II (Ang II), unaffected. However, dehydrated alligator embryos developed cholinergic tone on heart rate. Hypoxic incubated chicken embryos were reduced in embryo mass, and altered response to humoral regulatory components Ang I and adenosine in addition identifying a novel regulatory component of the cardiovascular response to acute hypoxia. Collectively, these studies add to the existing knowledge of cardiovascular physiology in embryonic archosaurs and suggest that some components of cardiovascular regulation are plastic following developmental stress.
Date: December 2014
Creator: Tate, Kevin B.
System: The UNT Digital Library
Predictive Relationships among Learner Characteristics, Academic Involvement, and Doctoral Education Outcomes (open access)

Predictive Relationships among Learner Characteristics, Academic Involvement, and Doctoral Education Outcomes

The literature identifies multiple factors pertinent to learner characteristics and learning experiences that may promote doctoral education outcomes, and yet little quantitative research has examined relationships between those factors deemed important in the effectiveness of doctoral education. This study sought to examine predictive relationships among doctoral students’ learner characteristics, their involvement in mentorship and intellectual community, and doctoral education outcomes. Using Astin’s theory of involvement and the literature on signature pedagogies in doctoral education as conceptual guides, a survey instrument was constructed for the purpose of measuring variables identified as relevant to the effective formation of scholars. Central to the conceptualization of this study was academic involvement as represented by mentorship and intellectual community. The instrument was validated in a two-stage pilot testing process and administered to doctoral candidates at three public Texas higher education institutions. Of the 217 participants, the majority were female, White (Non-Hispanic), US citizens, and were pursuing education doctorates. Data were analyzed using multivariate statistical analyses. Reliability and validity estimates indicated psychometric integrity of the 20 observed variables measured to represent the constructs of mentorship and intellectual community. Results indicated that doctoral students’ learner characteristics were not notably predictive of doctoral students’ degree of involvement in …
Date: December 2011
Creator: Anderson, Baaska
System: The UNT Digital Library