Background: Many Australians do not meet recommended levels of physical activity and GPs can play an important role in addressing this. Objectives: To evaluate the effectiveness of an exercise referral scheme, in patients referred by their general practitioner (GP). Design: A pre post evaluation with measurement of outcomes immediately post intervention (five weeks) and again at six months. Intervention: The 42 patients that agreed to participate in the study took part in an initial fitness and lifestyle assessment with an exercise physiologist. They then undertook ten exercise sessions over a period of five weeks, following an individually prescribed exercise program. At the completion of the ten exercise sessions, participants were reassessed (fitness and lifestyle) by the exercise physiologist. This was repeated again six months after they completed the intervention. Main outcomes measured: The primary outcomes measured were changes in self reported physical activity and associated markers including cardiovascular fitness. Secondary outcomes measured include changes in physiological and anthropometric measures, behavioural risk factors (dietary behaviour, alcohol consumption and smoking) and quality of life. Patient well-being (using SF12), patient satisfaction and GP satisfaction with the program was also assessed. Results: There was a large withdrawal of participants. Results have been presented in terms of outcome frequency at each assessment point. There was an 18% increase (from baseline) in the proportion of participants achieving the Australian physical activity guidelines and a 31% increase between baseline and the six month follow-up assessment in those that completed the program. There were statistically significant improvements in cardiovascular fitness measures and small improvements in some physiological, anthropometric, dietary behaviours and general well being measures. Conclusions: The results of this study suggest that referral to a community based leisure centre for supervised exercise, supported by a written exercise prescription by an exercise physiologist, may be effective in increasing physical activity levels short and long term in those that complete the program. Exercise referrals can form part of national strategies to increase physical activity, particularly for primary care.

The homotetrameric enzyme dihydrodipicolinate synthase (DHDPS, E.C. 4.2.1.52) from Escherichia coli was used as a model for probing oligomeric structure in enzymes. Dimeric mutants of this enzyme have been found in previous work to be largely inactive, due to the trapping of a covalent adduct. Partial restoration of catalytic activity has been achieved by incubation in the presence of the substrate pyruvate to displace the adduct. It was hypothesized that the buttressing of dimeric units against one another in the wildtype tetrameric form of DHDPS provides stability in the dimer interface, necessary to maintain optimum catalytic performance and substrate specificity. We hypothesized that buttressing a dimeric DHDPS mutant against a surface would result in restoration of catalytic activity by mimicking the buttressing proposed to occur in the tetrameric structure. To test this hypothesis, dimeric DHDPS mutants were immobilised against an agarose support and the immobilised enzymes characterised. Three DHDPS mutants were prepared, the double mutant DHDPS-C20S/L167C was produced by mutagenesis and a crystal structure obtained in collaboration with Dr Renwick Dobson. Two other mutants, DHDPS-Ll67C and DHDPS-Ll97Y were also over expressed and purified. The quaternary structures of the three mutants were characterised in solution, DHDPS-Ll67C was determined to be tetrameric, DHDPS-C20S-Ll67C was found to equilibrate between tetramer and dimer and DHDPS-Ll97Y was confirmed as a dimer, consistent with previous findings. Modification experiments indicated that the sulfhydryl groups of DHDPS-C20S/L167C were available for immobilisation. Activation experiments indicated that both DHDPS-Ll67C and DHDPS-Ll97Y activated. These results were in accord with those of others in indicating that the displacement of an a-ketoglutarate adduct from the active site was responsible for the activation of mutant DHDPS enzymes. Wild-type DHDPS and the mutants were immobilised through amine and sulfhydryl groups. The free and immobilised enzymes were rigorously characterised, with thermal stability, pH optima, kinetic and lysine inhibition properties determined and compared to wild-type DHDPS. Following immobilisation, substrate affinity was found to decrease for wild-type and mutant enzymes, wild-type KmPyr = 0.26 mM free, 0.8-1.2 mM immobilised, Km(S)-ASA = 0.10 mM free, 1.5-2.5 mM immobilised. Lysine inhibition was determined to be largely unaffected by immobilisation. The largest change in K, was an increase to double that of the free enzyme. Restoration of some catalytic activity was found following the immobilisation of dimeric DHDPS-Ll97Y, the immobilised enzyme was 31 ± 12% more active than free DHDPS-Ll97Y. DHDPS-C20S/L167C was also found to immobilise as a dimer. Comparison ofthe immobilised DHDPS-C20S/L167C dimer with a derivatised free dimeric form ofthis enzyme indicated that an increase from 3% to 9% of wild-type activity had resulted from immobilisation. These results supported the hypothesis that buttressing of a dimeric mutant of DHDPS against a support surface would increase catalytic activity and that buttressing across the dimerdimer interface is essential for optimal catalytic activity in DHDPS enzymes.

In this project I investigate university students orientations to learning statistics. The students who participated in my research were studying statistics as a compulsory component of their psychology course. My central thesis is that learning develops in the relationship between the thinking, feeling and acting person and the social, institutional and cultural contexts surrounding him or her. How students orient themselves or position themselves to learn statistics is reflected in their engagement with the learning task and their activities. These activities determine the quality of their learning and emerging knowledge. To understand student learning I draw on the powerful theories of Vygotsky (1962, 1978) and Leontev (1978, 1981). In particular, I extend and apply Leontev's construct of activity (Leontev, 1981). This suggests that individuals act in accordance with their purposes and needs which are shaped by and reflect histories and resources, both personal and cultural. My investigation consists of two studies. Study One is a qualitative exploration of the orientations to learning statistics of five older students. These students sought help with statistics at the Mathematics Learning Centre where I work. My case studies of these students are inseparable from my efforts to help them learn statistics. Study Two is grounded in Study One. The main source of data for this broader study is a survey which was completed by 279 psychology students studying statistics. In keeping with the theoretical framework, my methodology involves a holistic analysis of students and the milieu in which they act. My findings suggest relationships among students affective appraisals; their conceptions of statistics; their approaches to learning it; their evaluations and the outcomes of their actions. In Study One the relationships emerged from the students' descriptions. In Study Two I quantified the ways in which variables related to each other. Structure for the data was provided by means of correlations, factor analysis and cluster analysis. For this study I also interviewed students and teachers of statistics. My data support the systemic view of teaching and learning in context afforded by my theoretical perspective. Learning statistics involves the whole person (Semenov, 1978) and is inseparable from the arena of his or her actions. The goal of statistics education is surely to enable students to develop useful, meaningful knowledge. My findings suggest that for many of the participants in my project this goal was not being met. Most of these students reported their reluctance to learn statistics and described adopting primarily surface approaches to learning it. A range of conceptions of the subject was expressed, but for many of the students statistical meaning was evidently reduced to performance on assessment tasks. Such orientations to learning statistics may lead to it becoming irrelevant and inert information. For a few students, however, the experience of learning statistics led to self development and enhanced perspectives on the world in which we live. My project indicates the diversity of students' experiences. It raises issues as to why we teach statistics today and how the teaching and learning of statistics is being supported at university. //REFERENCES Leontev, A. N. (1978). Activity, Consciousness, and Personality. (M. J. Hall, Trans.). Englewood Cliffs, New Jersey: Prentice-Hall. Leontev, A. N. (1981). The problem of activity in psychology. In J. V. Wertsch (Ed.), The Concept of Activity in Soviet Psychology, (pp. 37-71). New York: M. E. Sharpe. Semenov, N. (1978). An empirical psychological study of thought processes in creative problem-solving from the perspective of the theory of activity. Soviet Psychology, 16(1), 3-46. Vygotsky, L. S. (1962). Thought and Language. Cambridge, Massachusetts: The M.I.T. Press. Vygotsky, L. S. (1978). Mind in Society. Cambridge, MA: Harvard University Press.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 6 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Thesis (Ph.D.) OGI School of Science & Engineering at OHSU, March 2008. / Includes bibliographical references (leaves 98 - 99).

Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: leaf 257-281.

Thesis (Ph. D.)--University of New South Wales, 2003. / Also available online.

Lic.-avh. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 2 uppsatser.

Thesis (Ph. D.)--University of Toronto, 2007. / Source: Dissertation Abstracts International, Volume: 68-06, Section: A, page: 2289. Includes bibliographical references (leaves 202-219).