Effect of CDC25 and WEE1 on Plant Cell Cycle and Morphogenesis

The cell cycle comprise the four phases of, G1, S-phase, G2 and mitosis. Two critical transitions are G1/S and G2/M; the latter is regulated by WEE1 kinase and CDC25 phosphatases. The scope of this thesis was to investigate the regulation of the G2/M transition of the cell cycle by WEE1 and CDC25, and how these genes interface with plant growth regulators in Arabidopsis thaliana. In Arabidopsis roots, the frequency of lateral roots was found to be increased by ectopic expression of Schizosaccharomyces pombe (Sp)cdc25e and reduced by Arath;WEE1 expression. I examined the effect of Arath;WEE1 and Spcdc25 on induction of shoots and roots in Arabidopsis hypocotyls in vitro. Hypocotyl explants from two over-expressing WEE1 lines , three T-DNA insertion lines and two expressing cdc25 (Spcdc25e) lines together with wild type (WT) were cultured on two-way gradients of kinetin (Kin) and naphthyl acetic acid (NAA). Below a threshold concentration of NAA (100 ng ml-1), WEE1 repressed morphogenesis in vitro, whereas at all NAA/Kin combinations Spcdc25 promoted morphogenesis (particularly root formation) over and above that in WT. Loss of function wee1-1 cultures were very similar to WT. Quantitative data indicated a significant increase in the frequency of root formation in Spcdc25e cultures compared with WT particularly at low Kin concentrations, and WEE1oe’s repressive effect was overcome by NAA but not Kin. In conclusion, WEE1 has a repressive effect on morphogenesis in vitro that can be overcome by auxin whereas Spcd25 by-passes a cytokinin requirement for the induction of morphogenesis in vitro. The role of CDC25 and WEE1 in DNA damage responses was also analysed. Two over-expressing Arath;CDC25 lines and T-DNA mutants showed no difference to WT either in standard conditions or zeocin-supplemented treatments. However, root length was longer in Arath;CDC25oe lines treated with hydroxyurea (HU) and lateral root number was increased compared to WT. This suggests a differential response of Arath;CDC25oe in the DNA replication (HU-induced) and DNA damage (zeocin-induced) checkpoints (Chapter 5). Finally the roles of WEE1 and CDC25 in cell cycle regulation were examined using tobacco TBY-2 cell cultures expressing Arath;WEE1, Nicotiana tabacum (Nicta)WEE1 or Arath;CDC25. Whilst Nicta;WEE1 lengthened G2 of the cell cycle, Arath;WEE1 had an unusual effect of shortening G2 phase and Arath;CDC25 had no observable effect (Chapter 6).

Internationalization’s Effect on Marketing Learning: A Study of Syrian Firms

The aim of the present study is to understand the effects of international expansion on firms’ acquisition of marketing learning. This study’s focus on marketing learning complements previous research on the impact of internationalization on the development of foreign-market and technological knowledge. The research finds that the scope of a firm’s international activities, perception of gaps in marketing knowledge, and external social capital positively influence firms’ acquisition of marketing learning. However, firm’s age at initial international market entry appears not to be a significant factor. The study adds to the very limited body of research on the marketing learning outcomes of international expansion, while also offering rare empirical insights from the Middle East on this important subject matter. The paper discusses implications for international managers, policy makers, and future researchers.

Wearing Eye Tracking Technology During Batting Practice: Assessing the Experiences of Professional Baseball Athletes

Utilizing wearable technology in sport allows for the collection of motor behavior data during task engagement. This data can be assessed in real-time or retrospectively. Although enriching the scope of performance data, the consequences of wearable technology on the athlete-user, specifically the cognitive effects, has not been fully investigated, hence the purpose of this study. This qualitative study examines the cognitions of 57 professional baseball players who wore eye tracking technology whilst engaged in batting practice. Their verbal self-reports were framed by temporal context: before-during-after task. Three themes emerged during the pre-task segment: social appearance anxiety, claimed self-handicapping, and curiosity. During the task of batting, verbal behavior contained motivational and instructional overt self-talk while claimed self-handicapping was sustained. The final, post-performance segment was marked by the re-emergence of curiosity from the pre-task period as well as self-evaluation/appraisal. Given the participants were professional athletes, their performance has greater career implications than amateur competitors. Nonetheless, the verbal behavior elicited while wearing eye tracking technology indicates an awareness of the equipment by the user. This study found cognitive effects from wearable technology; more research is required to under-stand the scope and nature of those effects on cognitive and motor behaviors.

An Exploration of the Data Collection Methods Utilised with Children, Teenagers and Young People (CTYPs)

Background: The impact of cancer upon children, teenagers and young people can be profound. Research has been undertaken to explore the impacts upon children, teenagers and young people with cancer, but little is known about how researchers can ‘best’ engage with this group to explore their experiences. This review paper provides an overview of the utility of data collection methods employed when undertaking research with children, teenagers and young people. A systematic review of relevant databases was undertaken utilising the search terms ‘young people’, ‘young adult’, ‘adolescent’ and ‘data collection methods’. The full-text of the papers that were deemed eligible from the title and abstract were accessed and following discussion within the research team, thirty papers were included. Findings: Due to the heterogeneity in terms of the scope of the papers identified the following data collections methods were included in the results section. Three of the papers identified provided an overview of data collection methods utilised with this population and the remaining twenty seven papers covered the following data collection methods: Digital technologies; art based research; comparing the use of ‘paper and pencil’ research with web-based technologies, the use of games; the use of a specific communication tool; questionnaires and interviews; focus groups and telephone interviews/questionnaires. The strengths and limitations of the range of data collection methods included are discussed drawing upon such issues as of the appropriateness of particular methods for particular age groups, or the most appropriate method to employ when exploring a particularly sensitive topic area. Conclusions: There are a number of data collection methods utilised to undertaken research with children, teenagers and young adults. This review provides a summary of the current available evidence and an overview of the strengths and limitations of data collection methods employed.