2015 MU dissertations - Access restricted to UM
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Item The role of myostatin deficiency in the development and biomechanical integrity of offspring bone(University of Missouri--Columbia, 2015) Oestreich, Arin Kettle; Schulz, Laura C.; Phillips, Charlotte LOsteogenesis imperfecta (OI) is a genetic bone disorder primarily caused by mutations to the genes for type I collagen, a major structural protein found in bone. There have been over 1,500 different mutations described that cause OI which lead to bone deformity, fragility, scoliosis, and increased fracture incidence. There is no cure for OI and treatment strategies remain limited. It is known that bone naturally responds to the forces it encounters from muscle loading by remodeling its structure to withstand these forces. We hypothesized that increasing muscle mass in a mouse model of osteogenesis imperfecta (oim) would be a therapeutic target to improve bone quality and strength. To test this hypothesis, a mouse model with inherently large muscles due to a deficiency in a protein called myostatin was bred to the oim mouse model. Our findings demonstrated that increased muscle mass in the oim mouse was able to alter the bone microarchitecture and mineral composition to increase the overall biomechanical strength of the compromised oim bone. This data supports that inhibition of myostatin is a novel therapeutic target for increasing both muscle mass and bone strength, and our findings demonstrate the potential of myostatin inhibition as a therapeutic approach to treat OI. Additionally, my research has explored maternal factors contributing to offspring bone development, maturation, and biomechanical integrity. During fetal development, changes in the uterine environment can have effects on offspring bone quality that persist throughout life. The focus of the second half of my research was to better understand the role of myostatin, a regulator of muscle mass, in the uterine environment and its impact on the muscle and bone health of adult offspring. Previous research with mice has shown that decreasing myostatin in the maternal uterine environment during development causes offspring to have larger muscles as adults. In a separate study, my research demonstrates that the decrease of maternal myostatin during fetal development also increases bone strength of adult wildtype offspring. Understanding the factors within the uterine environment that contribute to offspring bone integrity may provide potential therapeutic targets for increasing bone quality of OI patients in utero, which would persist throughout their lifetime. Our results have shown that mice carrying the oim mutation and exposed to a decrease of myostatin in the uterine environment during development have a 16% increase in biomechanical strength as adults. To explore the critical time point when maternal myostatin programs offspring bone integrity, I performed embryo transfers using the oim mouse model and transferring embryos into recipient female dams with a deficiency in myostatin. Taken together, my data demonstrates that the decrease of myostatin in the uterine environment improves the skeletal integrity of adult mice and further, that inhibiting myostatin in utero may provide a new therapeutic window for treating OI.Item Behavioral consequences of polyploidy in hyla chrysoscelis treefrogs : implications for speciation and underlying mechanisms(University of Missouri--Columbia, 2015) Tucker, Mitch; Gerhardt, H. CarlPolyploidy occurs when organisms have more than the typical two copies chromosome sets. Polyploidy has occurred many times throughout plant and vertebrate evolution, and recently in diverse families of frogs. Male treefrogs produce acoustic advertisement-calls to attract females. Females reliably choose males of their own species on the basis of their advertisement-calls, which allows two gray treefrog species to live and breed amidst each other. To investigate the effects of polyploidy on behavior, I created artificial polyploids of the diploid gray treefrog, Hyla chrysoscelis. Polyploid males produce advertisement calls with slower pulse-rates, and consisting of pulses with slower rise-times, both in the direction of the tetraploid species, H. versicolor. Polyploid females also demonstrate a preference for calls with slower pulse-rates, and demonstrate weak preference for slow rise-time pulses, as do females of H. versicolor. These parallel effects of polyploidy undoubtedly contributed to the rapid establishment of early polyploids. I also documented differences in cell size and number between the two species. Cells of polyploids are larger, and fewer in number, than those of the diploids. Environmental temperature can also influence cell size: frogs grown at cooler temperatures have larger cells, similar to polyploids grown at normal temperatures. By comparing the behavior of diploid frogs grown in cooler temperature, polyploids, and wild type diploids, I can further determine the relative effects of cell size and other consequences of polyploidy, such as gene copy number.Item Stages of change, coparenting patterns, and post-divorce parent education programming : a pre-program assessment(University of Missouri--Columbia, 2015) Galovan, Adam M.; Schramm, David G.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Given concerns about the effect of divorce and interparental conflict on children, many judges now require divorcing/legally separating parents with children under age 18 to attend parent education programs (PEPs). In general, evaluations of these programs have shown their effectiveness. Evaluation studies of PEPs, however, have often not been rigorous. Despite the fact that researchers and practitioners acknowledge that individuals display markedly different patterns of coparenting following divorce and that not all program participants are amenable to making changes in their coparental relationship, researchers have not empirically assessed participants' coparenting patterns or stage of change prior to participation in PEP . Using latent class analysis of survey data from participants in a PEP class, this dissertation provides an initial evaluation of participants coparenting patterns and stage of change prior to participating in PEP and considers how demographic factors are related to both coparenting pattern and stage of change. The association between coparenting pattern and stage of change is also evaluated. Results from this evaluation suggest a need for a more tailored approach to parent education programming and have broader implications for family life education and relationships research.Item Does the benchmark assessment tool show a significant directional correlation between professional development and student achievement : what effect does the level of implementation of PLCs in schools have on student achievement?(University of Missouri--Columbia, 2015) Brotherton, Tammy Sue; Stader, David L.; Watkins, Paul[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Educational researchers agree on a few aspects of educational reform. First, in order for reform to happen in schools, professional development (PD) is essential. Educators need additional training once they move into the teaching profession. Secondly, PD should be evaluated to determine its effectiveness. Past forms of PD evaluation included participant reactions immediately after the PD session, survey of knowledge gained by the participants, and implementation levels of program objectives. These past evaluation forms are no longer enough. There is a significant need to evaluate PD using impact data. The bottom line as to whether or not the PD is considered effective is its impact on student achievement. Finally, many researchers agree there is a need to measure the implementation levels of PD formatively throughout its execution. However, this is time-consuming and expensive. There is a desperate need for a low-cost, time-efficient, formative PD evaluation tool directly linked to student achievement. State department authorities and school leaders need this information to make informed decisions on behalf of students and to allocate tax money more judiciously. Research for the necessity to monitor PD, as well as connect it to student success, is easier said than done. The Missouri Professional Learning Communities (MO PLC) project is using the Benchmark Assessment Tool (BAT) to formatively measure the level of implementation of Professional Learning Community (PLC) concepts in schools. The purpose of this quantitative study was to use an ANOVA test to determine if BAT scores from 331 schools across the state of Missouri had a significant correlation to math and English Language Arts (ELA) Missouri Assessment Program (MAP) index scores. By gathering BAT scores from schools all around the state, a variety of demographics were included in this study. Findings from this study revealed no significant correlation between BAT scores and math and ELA MAP index scores. Therefore, a null hypothesis was realized. As a result, the BAT cannot be used as a Guskey (2000) Level 5 evaluation tool for determining PD effectiveness because it does not show a significant impact on student achievement.Item Quantitative analysis of the relationship between factors of servant leadership, school culture and academic achievement in ten Missouri middle-level schools(University of Missouri--Columbia, 2015) Crain, Ty A.; Wall, Timothy J., 1972-; Edmonds, Carole[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The purpose of the study was to explore and analyze the relationships among the factors of servant leadership, school culture, and student achievement in Missouri public middle-level schools. The method of analysis was quantitative with survey data being used to determine if any relationships exist between factors of servant leadership, school culture and student achievement data from the 2014 Missouri Assessment Program tests in Mathematics and Communication Arts. A total of 119 teachers from 10 middle-level schools in Missouri comprised the population of the study. Data from the two surveys as well as student achievement data were aggregated at the school level and analyzed using Pearson product-moment coefficient correlations and multiple regression analysis to determine the relationships. The results suggest that principal servant leadership behaviors have statistically significant influence on the factors of school culture. The study also found that while controlling for enrollment and free and reduced lunch that free and reduced lunch statistically and significantly influenced student achievement. Explanatory models were designed from the findings to illustrate the relationships between servant leadership, school culture, and student achievement.