233 research outputs found
A qualitative case study of graduate assistantship experiences at the University of Central Missouri
Dr. Sandy Hutchinson, Dissertation Supervisor.Includes vita.Field of Study: Educational leadership and policy analysis."July 2018."This qualitative case study was designed to investigate graduate assistantships at the University of Central Missouri (UCM). Specifically, the researcher sought to understand how assistantships prepare graduate students for real world practices, provide a place to perfect their leaned skills, and assist with professional goal attainment. Participants of this study included current graduate assistants, previous graduate assistants, university leadership, and supervisors of graduate assistants. The conceptual framework of this research study incorporated Kolb's (1984), Experiential Learning Theory. This theory was chosen because it gives credibility to the concept that graduate assistantships can enrich learning and professional development (Johns, 2001; Kolb, 1984). Data collection for this study consisted of individual interviews, a focus group and an online survey. Furthermore, data validity and reliability were enriched through strategies such as triangulation, adequate engagement in collection of data, member checking, and rich thick description (Creswell, 2014; Merriam & Tisdell, 2016; Seidman, 2013). Analysis of the data revealed topics such as professional development effectiveness, opportunities and experience, and the organizational value of graduate assistantships. This information provides concrete evidence pertaining to the benefits and value of graduate assistantships at UCM.Includes bibliographical references (pages 162-170)
Two Strains of Crocosphaera watsonii with Highly Conserved Genomes are Distinguished by Strain-Specific Features
Unicellular nitrogen-fixing cyanobacteria are important components of marine phytoplankton. Although non-nitrogen-fixing marine phytoplankton generally exhibit high gene sequence and genomic diversity, gene sequences of natural populations and isolated strains of Crocosphaera watsonii, one of the two most abundant open ocean unicellular cyanobacteria groups, have been shown to be 98–100% identical. The low sequence diversity in Crocosphaera is a dramatic contrast to sympatric species of Prochlorococcus and Synechococcus, and raises the question of how genome differences can explain observed phenotypic diversity among Crocosphaera strains. Here we show, through whole genome comparisons of two phenotypically different strains, that there are strain-specific sequences in each genome, and numerous genome rearrangements, despite exceptionally low sequence diversity in shared genomic regions. Some of the strain-specific sequences encode functions that explain observed phenotypic differences, such as exopolysaccharide biosynthesis. The pattern of strain-specific sequences distributed throughout the genomes, along with rearrangements in shared sequences is evidence of significant genetic mobility that may be attributed to the hundreds of transposase genes found in both strains. Furthermore, such genetic mobility appears to be the main mechanism of strain divergence in Crocosphaera which do not accumulate DNA microheterogeneity over the vast majority of their genomes. The strain-specific sequences found in this study provide tools for future physiological studies, as well as genetic markers to help determine the relative abundance of phenotypes in natural populations
Molecular interconversion behaviour in comprehensive two-dimensional gas chromatography
Comprehensive two-dimensional gas chromatography (GC x GC) is shown to provide information on dynamic molecular behaviour (interconversion), with the interconversion process occurring on both columns in the coupled-column experiment. The experiment requires suitable adjustment of both experimental conditions and relative dimensions of each of the columns. In this case, a longer column than normally employed in GC x GC allows sufficient retention duration on the second column, which permits the typical plateau-shape recognised for the interconversion process to be observed. The extent of interconversion depends on prevailing temperature, retention time, and the phase type. Polyethylene glycol-based phases were found to result in high interconversion kinetics, although terephthalic acid-terminated polyethylene glycol had a lesser extent of interconversion. Much less interconversion was seen for phenyl-methylpolysiloxane and cyclodextrin phases. This suggests that for the oximes, interconversion largely occurs in the stationary phase. Examples of different extents of interconversion in both dimensions are shown, including peak coalescence on the first column with little interconversion on the second column
An atypical receiver domain controls the dynamic polar localization of the Myxococcus xanthus social motility protein FrzS
The Myxococcus xanthus FrzS protein transits from pole-to-pole within the cell, accumulating at the pole that defines the direction of movement in social (S) motility. Here we show using atomic-resolution crystallography and NMR that the FrzS receiver domain (RD) displays the conserved switch Tyr102 in an unusual conformation, lacks the conserved Asp phosphorylation site, and fails to bind Mg2+ or the phosphoryl analogue, Mg2+·BeF3. Mutation of Asp55, closest to the canonical site of RD phosphorylation, showed no motility phenotype in vivo, demonstrating that phosphorylation at this site is not necessary for domain function. In contrast, the Tyr102Ala and His92Phe substitutions on the canonical output face of the FrzS RD abolished S-motility in vivo. Single-cell fluorescence microscopy measurements revealed a striking mislocalization of these mutant FrzS proteins to the trailing cell pole in vivo. The crystal structures of the mutants suggested that the observed conformation of Tyr102 in the wild-type FrzS RD is not sufficient for function. These results support the model that FrzS contains a novel ‘pseudo-receiver domain’ whose function requires recognition of the RD output face but not Asp phosphorylation
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Refining genetic boundaries for Agassiz’s desert tortoise (Gopherus agassizii) in the western Sonoran Desert: the influence of the Coachella Valley on gene flow among populations in southern California
Understanding the influence of geographic features on the evolutionary history and population structure of a species can assist wildlife managers in delimiting genetic units (GUs) for conservation and management. Landscape features including mountains, low elevation depressions, and even roads can influence connectivity and gene flow among Agassiz’s desert tortoise (Gopherus agassizii) populations. Substantial changes in the landscape of the American Southwest occurred during the last six million years (including the formation of the Gulf of California and the lower Colorado River), which shaped the distribution and genetic structuring of tortoise populations. The area northwest of the Gulf of California is occupied by the Salton Trough, including the Coachella Valley at its northern end. Much of this area is below sea level and unsuitable as tortoise habitat, thus forming a potential barrier for gene flow. We assessed genetic relationships among three tortoise populations separated by the Coachella Valley. Two adjacent populations were on the east side of the valley in the foothills of the Cottonwood and Orocopia mountains separated by Interstate 10. The third population, Mesa, was located about 87 km away in the foothills of the San Bernardino Mountains at the far northwestern tip of the valley. The Cottonwood and Orocopia localities showed genetic affiliation with the adjacent Colorado Desert GU immediately to the east, and the Mesa population exhibited affiliation with both the Southern Mojave and Colorado Desert GUs, despite having a greater geographic distance (0.5x–1.5x greater) to the Colorado Desert GU. The genetic affiliation with the Colorado Desert GU suggests that the boundary for that GU needs to be substantially extended to the west to include the desert tortoise populations around the Coachella Valley. Their inclusion in the Colorado Desert GU may benefit these often overlooked populations when recovery actions are considered
Are Small Reimbursement Changes Enough to Change Cancer Care? Reimbursement Variation in Prostate Cancer Treatment
The Centers for Medicare and Medicaid Services recently initiated small reimbursement adjustments to improve the value of care delivered under fee-for-service. To estimate the degree to which reimbursement influences physician decision making, we examined utilization of gonadotropin-releasing hormone (GnRH) agonists among urologists as Part B drug reimbursement varied in a fee-for-service environment
Effect of state-mandated insurance coverage on accrual to community cancer clinical trials
Thirty-five U.S. states and territories have implemented policies requiring insurers to cover patient care costs in the context of cancer clinical trials; however, evidence of the effectiveness of these policies is limited. This study assesses the impact of state insurance mandates on clinical trial accrual among community-based practices participating in the NCI Community Clinical Oncology Program (CCOP), which enrolls approximately one-third of all NCI cancer trial participants. We analyzed CCOP clinical trial enrollment over 17 years in 37 states, 14 of which implemented coverage policies, using fixed effects least squares regression to estimate the effect of state policies on trial accrual among community providers, controlling for state and CCOP differences in capacity to recruit. Of 91 CCOPs active during this time, 28 were directly affected by coverage mandates. Average recruitment per CCOP between 1991 and 2007 was 95.1 participants per year (SD = 55.8). CCOPs in states with a mandate recruited similar numbers of participants compared to states without a mandate. In multivariable analysis, treatment trial accrual among CCOPs in states that had implemented a coverage mandate, was not statistically different than accrual among CCOPs in states that did not implement a coverage mandate (β = 2.95, p = 0.681). State mandates did not appear to confer a benefit in terms of CCOP clinical trial accrual. State policies vary in strength, which may have diluted their effect on accrual. Nonetheless, policy mandates alone may not have a meaningful impact on participation in clinical trials in these states
Sexual Health Education from the Perspective of School Staff: Implications for Adoption and Implementation of Effective Programs in Middle School
Introduction: US teens are having sex early; however, the vast majority of schools do not implement evidence-based sexual health education (SHE) programs that could delay sexual behavior and/or reduce risky behavior. This study examines middle school staff’s knowledge, attitudes, barriers, self-efficacy, and perceived support (psychosocial factors known to influence SHE program adoption and implementation). Methods: Professional school staff from 33 southeast Texas middle schools completed an internet or paper-based survey. Prevalence estimates for psychosocial variables were computed for the total sample. Chi-square and t-test analyses examined variation by demographic factors. Results: Almost 70% of participants were female, 37% white, 42% black, 16% Hispanic; 20% administrators, 15% nurses/counselors, 31% non-physical education/non-health teachers, 28% physical education/health teachers; mean age = 42.78 years (SD = 10.9). Over 90% favored middle school SHE, and over 75% reported awareness of available SHE curricula or policies. More than 60% expressed confidence for discussing SHE. Staff perceived varying levels of administrator (28%-56%) support for SHE and varying levels of support for comprehensive sex education from outside stakeholders (e.g., parents, community leaders) (42%-85%). Overall, results were more favorable for physical education/health teachers, nurses/counselors, and administrators (when compared to non-physical education/non-health teachers) and individuals with experience teaching SHE. Few significant differences were observed by other demographic factors. Conclusions: Overall, study results were extremely positive, which may reflect a high level of readiness among school staff for adopting and implementing effective middle school SHE programs. Study results highlight the importance of several key action items for schools
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