Seismicity and seismic risk in Australasia

Imperial Users onl

On the Biochemistry, Mechanism and Physiological Role of Fungal Nitronate Monooxygenase

Nitronate monooxygenase (E.C. 1.13.11.16), formerly known as 2-nitropropane dioxygenase (EC 1.13.11.32), is a flavin dependent enzyme that catalyzes the oxidation of nitronates to their corresponding carbonyl compounds and nitrite. Despite the fact that the enzyme was first isolated from Neurospora crassa 60 years ago, the biochemical and physiological properties of nitronate monooxygenase have remained largely elusive. This dissertation will present the work that established both the catalytic mechanism and physiological role of the fungal enzyme. The biological and biochemical properties of propionate-3-nitronate, the recently discovered physiological substrate for nitronate monooxygenase, will be extensively reviewed. The nitronate is produced by a variety of variety leguminous plants and fungi and is a potent and irreversible inhibitor of succinate dehydrogenase. Nitronate monooxygenase allows N. crassa to overcome the toxicity of propionate-3-nitronate as demonstrated by in vivo studies of the yeast, which showed that the wild-type can grow in the presence of the toxin whereas a knock out mutant that lacks the gene encoding for the enzyme could not. In addition to establishing the physiological role of nitronate monooxygenase, the work presented here demonstrates that the catalytic mechanism of the enzyme involves the formation of an anionic flavosemiquinone intermediate. This intermediate is stabilized by the protonated form of an active site histidine residue (His-196) that acts as an electrostatic catalyst for the reaction as demonstrated by pH studies of the reductive half reaction of the enzyme. Histidine 196 also serves as the catalytic base for the reaction of the enzyme with nitroethane as substrate as revealed through mutagenesis studies in which the residue was replaced with an asparagine. The kinetic implications of branching of reaction intermediates in enzymatic catalysis are also demonstrated through studies of the kinetic isotope effects of nitronate monooxygenase with 1,1-[2H2]-nitroethane as substrate. Finally the use of competitive inhibitors as a probe of enzyme structure will be presented through a study of the inhibition of nitronate monooxygenase with mono-valent inorganic ions. The dissertation will close with unpublished work on the enzyme and concluding remarks concerning the biochemistry and physiology of nitronate monooxygenase

A Behavioral Intervention For Child Obesity: Increasing Physical Activity On The Playground Via Reinforcement In A Preschool Classroom

Child obesity rates have reached an all-time high in the United States with rates quadrupling since 1963 for children ages 2-5 (Fryar, Caroll, & Ogden, 2012). This has led to increased research directed toward understanding the causes of this proliferation. The literature shows that several key variables, including physical activity level, diet, and health education are related to childhood obesity (Epstein, 2005; Trost, et al., 2003). In the realm of physical activity level, many interventions have been proposed and conducted with varying degrees of success. Only few have attempted to impact the physical activity level of children in free play, probably due to the complex nature of free play periods. In addition, activity preference is an important but often neglected aspect of free play since choice complicates the ability to influence physical activity level. The current study describes an intervention that attempted to increase physical activity level as well as determine if activity preference changes as a result of providing reinforcement for physical activity. Using behavior modification techniques associated with a classroom token economy, preschoolers\u27 moderate-to-vigorous physical activity on the playground was reinforced in attempt to influence both level of physical activity and activity preference. Also, in order to better understand the importance of peer influences on activity, sociometric interviews were conducted with the children before, during, and after the intervention. Accelerometers were used on the playground throughout the study to determine both which children were physically more or less active, and to measure any increase or decrease in level of physical activity. Several statistical tests were used to determine significant differences between mean activity level at pre-, during, and post-intervention, and sociometric interview data were analyzed for relationships among sociometric variables and activity levels. Results regarding the effectiveness of the intervention were inconclusive, as 50% of participants did not respond and the other 50% significantly increased their activity levels on the playground. Conclusions based on findings suggest a need for closer control of the magnitude and quality of reinforcement in order to increase response rate and that reinforcement-based intervention could be useful on playgrounds in equipment poor environments

An analysis of the factors influencing the implementation of health and personal social service policies for elderly people in Northern Ireland.

SIGLEAvailable from British Library Document Supply Centre- DSC:D66285/86 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Brood-rearing Period Cover Use By Wild Turkey Hens in Southcentral South Dakota

Brood-rearing period cover use by wild turkey (Meleagris gallopavo) hens with broods and those without, in Gregory County, South Dakota, was determined in order to formulate management suggestions for grassland/riparian woodland habitat. Two hens with broods and 12 hens without broods were studies through telemetry and direct observations form 5 July through 2 August and 3 August through 17 August of 1982 and 1982. Vegetational data were collected in 1983. Hens with broods selected for the grass/forb-dominated understory and 52% open canopy of south-facing savannah woodlands while their broods were less than 4 weeks of age. After 4 weeks, broods moved to the shrubby understory and 7% open canopy of north-facing bur oak forest. Broods hens did not appear to use cultivated fields, farmsteads, or bottomlands, and grasslands were avoided or used in proportion to availability. Hens without broods used cultivated fields, farmsteads, and bottomlands in proportion to availability, generally avoided grasslands, and selected woodlands

How Do Teachers Experience Lesson Study?

For the past 20 years, an increasing number of American educators have employed the Japanese model of lesson study as a process to structure their professional development experience. This study endeavored to understand how teachers experienced this relatively new and foreign process in their local contexts, using the overall research question, “How do teachers experience lesson study?” Leveraging hermeneutic phenomenology, the research was based on semi-structured phone interviews of 15 educators. These educators were from various regions in America, two from the Far East, and one from Europe. In describing their professional development experiences prior to lesson study, participants overlapped their terms, which signaled confusion. This was emblematic of their overall experiences with professional development. In general, participants found their professional development to be inapplicable, ineffective, and random. Additionally, they experienced issues sustaining their new learning even when they felt their professional development events were effective. Overall, participants believed their professional development time prior to lesson study was squandered. Participants experienced lesson study as an effective approach to professional development. Out of the 15 participants, 14 stated lesson study was the best form of professional development they experienced in their careers. They felt confident in the formal, yet flexible process. Lesson study offered the participants practice based, shared experiences learning about standards, curriculum, materials, and content fueled by structured collaboration. It changed their dispositions towards professional development. They contended lesson study assisted them in learning more about their students. Participants reported increased feelings of efficacy and professionalism after completing lesson study cycles. However, participants also described how their lesson study work was impeded by systemic obstacles including time, competing initiatives, misconceptions about lesson study, principal turnover, and interpersonal complications. This study adds information about lesson study obstacles in relation to school climate. They were frustrated by the local facilitation of their lesson study professional development. The participants found that the American system was ill-suited to support their lesson study experiences in the way that it is supported in Japan. This research informs those interested in using lesson study as a professional learning community. Further, it adds information to the discussion about professional development in general and the role of collaboration in this regard