DNA polymerase activity in trophoblast giant cells in the mouse /

In the developing mouse embryo, the diploid trophectoderm is known to undergo a diploid to giant cell transformation. These cells arise by a process of endoreduplication, characterized by replication of the entire genome without subsequent mitosis or cell division, leading to polyploidy and the formation of giant nuclei. Studies of 13.5 day rat trophoblast derived from the parietal yolk sac have indicated a relatively low rate of DNA polymerase a activity, the noinnal eukaryotic replicase, in comparison to that of DNA polymerase g. These results have suggested that endoreduplication in trophoblast giant cells may not employ the normal replicase enzyme, DNA polymerase a. In order to determine whether a 'switch' from DNA polymerase to DNA polymerase is a necessary concomitant of the diploid to giant cell transformation, two distinct populations of trophoblast giant cells, the primary giant cell derived from the mural trophectoderm and the secondary giant cell derived from the polar trophoectoderm were used. These two populations of trophoblast giant cells can be obtained from the tissue outgrowths of 3.5da blastocysts and the extraembryonic ectoderm (EX) and ectoplacental cone (EPC) of 7.5 day embryos respectively. Tissue outgrowths were treated with aphidicolin, a specific reversible inhibitor of eukaryotic DNA polymerase a, on various days after explantation. The effect of aphidicolin treatment was assessed both qualitatively, using autoradiography and quantitatively by scintillation counting and Feulgen staining. 3 DNA synthesis was measured in control and treated cultures after a Hthymidine pulse. Scintillation counts of the embryo proper revealed that DNA synthesis was consistently inhibited by greater than 907. in the presence of aphidicolin. Inhibition of DNA synthesis in the EX and EPC varied between 81-957. and 82-987. respectively, indicating that most DNA synthesis was mediated by DNA polymerase a, but that a small but significant amount of residual synthesis was indicated. A qualitative approach was then applied to determine whether the apparent residual DNA synthesis was restricted to a subpopulation of giant cells or whether all giant cells displayed a low level of DNA synthesis. Autoradiographs of the ICM of blastocysts and the embryo proper of 7.5da embryos, which acted as diploid control population, was completely inhibited regardless of duration in explant culture. In contrast, primary trophoblast giant cells derived from blastocysts and secondary giant cells derived from the EX and EPC were observed to possess some heavily labelled cells after aphidicolin treatment. These results suggest that although DNA polymerase a is the primary replicating enzyme responsible for endoreduplication in mouse trophoblast giant cells, some nonactivity is also observed. A DNA polymerase assay employing tissue lysates of outgrown 7.5da embryo, EX and EPC tissues was used to attempt to confirm the presence of higher nonactivity in tissues possessing trophoblast giant cells. Employing a series of inhibitors of DNA polymerases, it would appear that DNA polymerase a is the major polymerase active in all tissues of the 7.5da mouse embryo. The nature of the putative residual DNA synthetic activity could not be unequivically determined in this study. Therefore, these results suggest that both primary and secondary trophoblast giant cells possess and use DNA polymerase a in endoreduplicative DNA synthesis. It would appear that the high levels of DNA polymerase g activity reported in trophoblast tissue derived from the 13.5 da rat yolk sac was not a general feature of all endoreduplication.

3D movement and muscle activity patterns in a violin bowing task

Objective: Overuse injuries in violinists are a problem that has been primarily analyzed through the use of questionnaires. Simultaneous 3D motion analysis and EMG to measure muscle activity has been suggested as a quantitative technique to explore this problem by identifying movement patterns and muscular demands which may predispose violinists to overuse injuries. This multi-disciplinary analysis technique has, so far, had limited use in the music world. The purpose of this study was to use it to characterize the demands of a violin bowing task. Subjects: Twelve injury-free violinists volunteered for the study. The subjects were assigned to a novice or expert group based on playing experience, as determined by questionnaire. Design and Settings: Muscle activity and movement patterns were assessed while violinists played five bowing cycles (one bowing cycle = one down-bow + one up-bow) on each string (G, D, A, E), at a pulse of 4 beats per bow and 100 beats per minute. Measurements: An upper extremity model created using coordinate data from markers placed on the right acromion process, lateral epicondyle of the humerus and ulnar styloid was used to determine minimum and maximum joint angles, ranges of motion (ROM) and angular velocities at the shoulder and elbow of the bowing arm. Muscle activity in right anterior deltoid, biceps brachii and triceps brachii was assessed during maximal voluntary contractions (MVC) and during the playing task. Data were analysed for significant differences across the strings and between experience groups. Results: Elbow flexion/extension ROM was similar across strings for both groups. Shoulder flexion/extension ROM increaslarger for the experts. Angular velocity changes mirrored changes in ROM. Deltoid was the most active of the muscles assessed (20% MVC) and displayed a pattern of constant activation to maintain shoulder abduction. Biceps and triceps were less active (4 - 12% MVC) and showed a more periodic 'on and off pattern. Novices' muscle activity was higher in all cases. Experts' muscle activity showed a consistent pattern across strings, whereas the novices were more irregular. The agonist-antagonist roles of biceps and triceps during the bowing motion were clearly defined in the expert group, but not as apparent in the novice group. Conclusions: Bowing movement appears to be controlled by the shoulder rather than the elbow as shoulder ROM changed across strings while elbow ROM remained the same. Shoulder injuries are probably due to repetition as the muscle activity required for the movement is small. Experts require a smaller amount of muscle activity to perform the movement, possibly due to more efficient muscle activation patterns as a result of practice. This quantitative multidisciplinary approach to analysing violinists' movements can contribute to fuller understanding of both playing demands and injury mechanisms .

Investigation of motivation strategies used by school teachers for workplace engagement

The purpose of this study was to explore the strategies that elementary school teachers use to be engaged in their work. Participation was solicited from a random sample of schools stratified by location (i.e., urban, inner city, and rural) of a large school board. The study used an anonymous quantitative/qualitative questionnaire. The survey tool was based upon Kahn's (1990) psychological engagement framework, which presents the foundation of availability of self, meaningfulness of work, and safety while at work. Forty-one surveys were analyzed descriptively including a subgroup of self-rated highly engaged teachers. Teachers tended to favour physical and emotional strategies compared to cognitive type strategies, with the exception of the highly engaged subgroup. The theme of preferred strategies reflected a setting outside the school/workplace, that is, a preference for horne based strategies. The study's main contribution highlights the teachers' sense of importance for physical and emotional health in a profession that is heavily focused in the cognitive domain. This may influence administrative and teacher discourse regarding workplace engagement with strategies to help reduce stress and to maintain and increase teacher engagement.

Understanding Workplace Essential Skills: A Student's Perspective

An instrumental case study was conducted to explore the perspective of recent graduates from a Greater Toronto Area community college experience in relation to Workplace Essential Skills (WES). Five participants who graduated from a business school within the last 4 years were interviewed twice over a 4-month period to gain a deeper understanding of this relationship. This qualitative approach used semi-structured interviews to elicit stories about their experiences, their relationships in school, and the development of skills that were useful in the workplace. The analysis of data involved the 3-step coding process of open, axial, and selective coding consistent with the approach used by Neuman (2006). The analysis revealed that the overall experience of attending college contributed to the learning that took place. The participants gave greater significance to the life experience in learning WES and the networks associated with learning than the formal aspects of education. It is also important to acknowledge that the research identified a significant opportunity for educators’ to positively impact the learning experience.

Factors Contributing to Reading Performance: An In-Depth Analysis of the “Boy Crisis”

This research used a quantitative study approach to investigate the “boy crisis” in Canada. Boy crisis advocates suggest that boys are being surpassed by girls on reading assessments and promote strategies to assist male students. A feminist framework was used in this study that allowed for an investigation and discussion of the factors that mediate between gender and success at reading comprehension, interpretation, and response to text without ignoring female students. Reading scores and questionnaire data compiled by the Pan-Canadian Assessment Program were used in this research, specifically the PCAP-13 2007 assessment of approximately 30,000 13-year-old students from all Canadian provinces and Yukon Territory (CMEC, 2008). Approximately 20,000 participants wrote the reading assessment, while 30,000 students completed the questionnaire responses. Predictor variables were tested using parametric tests such as independent samples t-test, one-way ANOVA, chi-square analysis, and Pearson r. Findings from this study indicate that although boys scored lower than girls on the PCAP-13 2007 reading assessment, factors were found to influence the reading scores of both male and female students to varying degrees. Socioeconomic status, perceptions of the reading material used in language arts classrooms, reading preference, reading interest, parental involvement, parental encouragement for reading, and self-efficacy were all found to affect the reading performance of boys and girls. Relationships between variables were also found and are discussed in this research. The analysis presented in this study allows parents, educators, and policy makers to begin to critically examine and re-evaluate boy crisis literature and offers suggestions on how to improve reading performance for all students of all socioeconomic backgrounds.

The Good, the Bad, and the Ugly: Critical Media Literacy and Disney Female Characters

The purpose of this research project was to use a qualitative approach to explore Critical Media Literacy (CML) with young girls by collaboratively analyzing Disney animated films. My goal was to provide a safe and encouraging space for children to share their perspectives and opinions of Disney animated female characters featured in The Little Mermaid (Ashman, Musker, & Clements, 1989), Cinderella (Disney, Geronimi, Jackson, & Luske, 1950), and The Princess and the Frog (Del Vecho, Clements, & Musker, 2009). I used CML as my theoretical framework as it provided an inquisitive approach to watching films, which, in turn, encouraged the participants to use critical thinking pertaining to the images of female characters in Disney. I also incorporated feminist theory as the majority of discussion revolved around the physical appearance of female characters as well as the participants’ understandings of femininity. I conducted two focus groups with 4 young girls, aged 7 to 11, to gain insight into their understanding of Disney female characters. An inquisitive and collaborative approach to watching films revealed three themes: (a) powerful women in Disney are mean and ugly; (b) heterosexual relationships are paramount; and (c) Disney Princesses are always pretty and nice. I concluded by recommending the importance of CML and collaborative film-watching with young children as the simplicity of asking questions encourages young people to become aware of, challenge, and think critically about the media they are consuming.

Educational Technology Decision-Making: A Case Study on Technology Acquisition for 746,000 Ontario Students

Very little research has examined K–12 educational technology decision-making in Canada. This collective case study explores the technology procurement process in Ontario’s publicly funded school districts to determine if it is informed by the relevant research, grounded in best practices, and enhances student learning. Using a qualitative approach, 10 senior leaders (i.e., chief information officers, superintendents, etc.) were interviewed. A combination of open-ended and closed-ended questions were used to reveal the most important factors driving technology acquisition, research support, governance procedures, data use, and assessment and return on investment (ROI) measures utilized by school districts in their implementation of educational technology. After participants were interviewed, the data were transcribed, member checked, and then submitted to “Computer-assisted NCT analysis” (Friese, 2014) using ATLAS.ti. The findings show that senior leaders are making acquisitions that are not aligned with current scholarship and not with student learning as the focus. It was also determined that districts struggle to use data-driven decision-making to support the governance of educational technology spending. Finally, the results showed that districts do not have effective assessment measures in place to determine the efficacy or ROI of a purchased technology. Although data are limited to the responses of 10 senior leaders, findings represent the technology leadership for approximately 746,000 Ontario students. The study is meant to serve as an informative resource for senior leaders and presents strategic and research-validated approaches to technology procurement. Further, the study has the potential to refine technology decision-making, policies, and practices in K–12 education.

Postsecondary Teaching and Learning Development Needs: Motivators and Barriers Associated With Participation in Educational Development

This study investigated instructor perceptions of motivators and barriers that exist with respect to participation in educational development in the postsecondary context. Eight instructors from a mid-size, research intensive university in south-western Ontario participated in semistructured interviews to explore this particular issue. Data were analyzed using a qualitative approach. Motivation theory was used as a conceptual framework in this study, referring primarily to the work of Ryan and Deci (2000), Deci and Ryan (1985), and Pink (2009). The identified motivators and barriers spanned all 3 levels of postsecondary institutions: the micro (i.e., the individual), the meso (i.e., the department or Faculty), and the macro (i.e., the institution). Significant motivators to participation in educational development included desire to improve one’s teaching (micro), feedback from students (meso), and tenure and promotion (macro). Significant barriers to participation included lack of time (micro), the perception that an investment towards one’s research was more important than an investment to enhancing teaching (meso), and the impression that quality teaching was not valued by the institution (macro). The study identifies connections between the micro, meso, macro framework and motivation theory, and offers recommendations for practice.

Personal Support Workers' Experience of Collaboration in a Long-Term Care Facility in Rural Ontario

The growing complexity of healthcare needs of residents living in long-term care necessitates a high level of professional interdependence to deliver quality, individualized care. Personal support workers (PSWs) are the most likely to observe, interpret and respond to resident care plans, yet little is known about how they experience collaboration. This study aimed to describe PSWs’ current experiences with collaboration in long-term care and to understand the factors that influenced their involvement in collaboration. A qualitative approach was used to interview eight PSWs from one long-term care facility in rural Ontario. Thematic analysis revealed three themes: valuing PSWs’ contributions, organizational structure, and individual characteristics and relationships. Collaboration was a difficult process for PSWs who felt largely undervalued and excluded. To improve collaboration, management needs to provide opportunities for PSWs to contribute and support the development of relationships required to collaborate.

Diversity Discourse and the Ontario Educator: The Understandings of Race and Whiteness Among New White Ontario Teachers

As a recent teacher education graduate, I have been left with more questions than answers about how to create and maintain an equitable and antioppressive classroom. These complicated questions of equity laid the groundwork for this study, which explored how new teachers understood diversity, specifically whiteness, and how they connected these perceptions to their course-related experiences in their teacher education program. Using a qualitative approach, this study problematized the lack of critical discussions around diversity taking place in Ontario teacher education courses. Through purposive, homogenous sampling, 7 new Ontario educators participated in a semistructured interview that focused on their experiences as teacher candidates and new teachers and their understandings and ideas regarding diversity, race, and more specifically, whiteness. The findings suggest that the greater Canadian discourse surrounding multiculturalism impacts the everyday diversity talk of the participants, and that problematic ideas of acceptance and tolerance are common. The findings also show a strong discomfort and unfamiliarity among the participants with the terms whiteness and white privilege. Finally, the results also revealed that new teachers have limited experience in their teacher education to discuss and learn about diversity, particularly critical discussions about race and privilege. Through this investigation, I aimed to bring attention to the necessity of having these critical, albeit difficult, discussions around diversity and whiteness in order to support new, predominately white, teachers.