http://espace.library.uq.edu.au/ The University of Queensland en Fez http://blogs.law.harvard.edu/tech/rss http://espace.library.uq.edu.au/view/UQ:158348 In this thesis I explore the phenomenon of the loss of political leadership. This is a problem which has not received much academic attention, yet it is important to understanding leadership in a broader sense. I examine the loss of leadership by using the writings of Niccolò Machiavelli to assess four Australian prime ministers: John Gorton, Malcolm Fraser, Bob Hawke and Paul Keating. From Machiavelli’s political writings and advice on successful leadership, I have drawn four criteria by which leaders can be measured. The leaders’ performance on these four measures can be used to explain their political success and failures. Machiavelli’s method was one of observation and description, from which he constructed advice for political leaders. He self-consciously sought to present advice to leaders based on the realities of human nature, rather than on abstract theory or moral principles, and it is for this reason that his ideas are relevant to systems beyond Florence of the 15th and 16th centuries. Many aspects of political systems vary, but in most respects human nature remains the same, and thus Machiavelli’s observations on leadership resonate today. The four measures of successful leadership I draw from Machiavelli are: political judgement and flexibility; the perception of strength; relationship with the public; and relationship with colleagues. To succeed, leaders need do well on each of these aspects of leadership, while poor performance on any will contribute to their loss of leadership. Australia’s post-World War II experience has seen only Sir Robert Menzies choose the manner of his departure from office, with most of the remaining leaders falling through either of two ways: a party-room deposition or electoral defeat. A prime minister’s style will affect the manner in which they lose their leadership. Of the four Australian prime ministers analysed and compared in this thesis, two ended their leadership through each of the two main forms of leadership loss. Similarities within, and contrasts between, the two groups of leaders exist. 2008-11-21T00:00:00Z Bateman, Joel http://espace.library.uq.edu.au/view/UQ:158078 2008-11-21T00:00:00Z Whiting, Claire http://espace.library.uq.edu.au/view/UQ:272923 The objective of this study was to investigate body condition score (BCS) at calving, the BCS profile during lactation, BCS effect on milk production, the main factors affecting BCS during lactation, and other measurements of BCS. BCS (scale 1 to 8) is a visual assessment of a cow’s body reserves and previous nutritional status. Genetic selection for higher milk production has indirectly selected cows which lose more BCS early in lactation to support milk production at the expense of reproductive efficiency. BCS at calving and monthly BCS during lactation were recorded at Mudtapilly Research Farm in 162 Holstein dairy cows. Individual cow milk production and composition data were recorded monthly. BCS at calving was negatively related to BCS change during lactation and positively related to calculated energy balance. In the second study, farm milk production records and climatic data was used to investigate factors affecting BCS during lactation on four commercial dairy farms in south-east Queensland. The main factor affecting herd BCS was the quality and nutritional characteristics of the concentrate fed to the cows during lactation. Similarly, the main factors affecting milk yield and composition were the quality and quantity of the cow’s diet. In the final experiment, other measurements of BCS were investigated and showed that physical cow measurements have the potential to replace visual BCS. Overall, this study has shown that BCS is a repeatable measurement of a cow’s body reserves and is a useful measurement in herd management, especially in early lactation. A system of management was devised to better manage dairy cows of varying genetic merit in relation to their BCS at calving. 2012-04-20T00:00:00Z Ivan Ward http://espace.library.uq.edu.au/view/UQ:219044 2010-10-26T00:00:00Z Hughes, David Edward. http://espace.library.uq.edu.au/view/UQ:218413 2010-10-13T00:00:00Z Drew, Henry Justin. http://espace.library.uq.edu.au/view/UQ:216288 The effects of varied protein content in the maternal diet during pregnancy are particularly relevant to the cattle industry in Australia, as protein is the most deficient rangeland nutrient, with the majority of replacement beef heifers requiring protein supplementation (Bortolussi et al., 2005a). This thesis aimed to provide information on the effects of breeder protein supplementation on placental and fetal growth, postpartum reproductive efficiency, milk production and potential fertility of the offspring. At artificial insemination (AI), to the same sire bull, two year-old composite beef heifers were divided into four dietary treatment groups: high/high (HH), high/low (HL), low/high (LH), low/low (LL), identified by the level of protein fed during the first and second trimesters, respectively, of gestation. High levels of dietary protein increased IGF-I, -II, IGFBP and leptin. Leptin was positively and IGF-I negatively associated with calf size at birth. We concluded that dietary protein affected maternal IGF and leptin impacting on fetal growth. To investigate the effects of gestational protein supplementation on the placenta at term, expelled placentas from the heifers were collected and weighed and cotyledons were dissected, counted, weighed and measured. The number of cotyledons and weight of the expelled placenta were influenced by the level of maternal dietary protein during gestation. Concentrations of maternal metabolic hormones negatively correlated with the number of cotyledons and placental weight. Calf birth weight, although closely positively associated with placental and cotyledonary weights and area, was not associated with the number of cotyledons. We concluded that dietary protein during gestation influenced placental measures at birth which were important contributors to fetal size. High levels of dietary protein decreased placental function as indicated by decreased bovine pregnancy associated glycoprotein (bPAG) and estrone sulphate (ES) concentrations in first trimester and decreased bovine placental lactogen (bPL) concentrations in the second trimester of gestation. In the third trimester, placental function was no longer associated with previous dietary treatments, yet placental ES corresponded to calf birth weight. We concluded that the placenta was able to compensate for altered maternal protein by changing function as needed to maintain normal fetal growth. Gestation length, placental expulsion time and the interval to the first oestrus postpartum (PPI) are considered to influence postpartum reproductive performance. Whilst the protein treatments imposed during gestation did not directly affect any of these measures in the heifers, high levels of protein during the first and second trimesters resulted in increased prepartum body condition (BCS), which in turn decreased the PPI. Calf size positively contributed to gestation length and PPI. Placental size negatively influenced placental expulsion time. Milk production was assessed monthly postpartum until weaning at 6 months. The milk yield was decreased in heifers receiving a high level of protein in first trimester. Milk production was negatively associated with BCS and leptin during lactation. Colostral protein content was influenced by dietary protein in the first trimester dependent upon genotype and positively associated with bPAG. This inferred that increased dietary protein during the early gestation of the adolescent heifer may have impaired mammary development and affected colostral protein via placental effects. Prenatal protein supplementation may be detrimental to the reproductive function of the offspring. Prepubertal gross testis measures, seminiferous tubule diameters, gonadotrophin, and testosterone concentrations were considered to be indicative of potential reproductive performance in the bull calves. Higher prenatal maternal dietary protein levels were associated with decreased prepubertal Follicle Stimulating Hormone (FSH) concentrations and paired testicular volumes. In the heifer calves, prepubertal measures were taken of gonadotrophin concentrations and ovarian parameters along with postpubertal concentrations of FSH and ovarian measures. Elevated dietary protein in the second trimester of gestation was associated with smaller sized prepubertal ovarian follicles and reduced densities of primordial plus primary follicles and healthy ovarian antral follicles in mature heifer offspring. This thesis constituted, to date, the most comprehensive study of the effects of nutritional protein in the beef heifer during gestation on placental and fetal development and their associations with placental markers and metabolic hormones. It also provided information on the influence of prenatal protein supplementation of heifers on their postpartum reproductive performance and the longer term effects on the reproductive potential of their calves. It conclusively demonstrated that maternal metabolic hormones and placental development respond to levels of nutritional protein during gestation affecting fetal growth. This thesis emphasised that the continuous monitoring of seasonally changing feed values and nutritional requirements of the pregnant growing heifer is essential to production. This thesis also provided the foundations on which to form subsequent studies to further explore long term effects of prenatal protein on reproductive function in offspring. 2010-09-12T00:00:00Z Tracy Sullivan http://espace.library.uq.edu.au/view/UQ:106720 2007-08-24T00:00:00Z McNamara, Simone M. http://espace.library.uq.edu.au/view/UQ:158440 Although a number of research groups have attempted to estimate the physiological demands of rugby league match-play in order to provide relevant data for the design of specific training programs, all have been subject to a number of limitations. The two studies that have used time motion analysis (TMA) were published before the introduction of influential rule changes and the findings from this previous research are arguably dated with regard to the contemporary demands encountered by professional rugby league players. Moreover, research is yet to compare contemporary TMA data with training programs presently used with professional rugby league players. In particular, it is not clear whether current training practices take account of the frequent bouts of very high-intensity activity that are believed to occur during passages of play and which can determine the outcome of a match. The primary aim of the present thesis was therefore to analyse the movement patterns specific to professional rugby league players during match-play (Study 1). A secondary aim was to identify the timing and frequency of the most highly intense periods of play (Study 2). The findings were then used to develop a highly specific training drill that would reflect the most physiologically demanding periods of the game. The physiological costs of this very high intensity activity reflecting the most demanding periods of a game were then examined in a modified drill and comparisons made between the costs of running alone versus running and tackling (Study 3). Furthermore, current training practices were assessed to determine whether they met the physiological demands identified through TMA (Study 4). Study 1 examined the movement patterns and physiological demands of specific positional groups (hit-up forwards, adjustables and outside backs) during competition using time motion analysis (TMA). There were significant (P < 0.05) differences between the distances covered by the three positional groups and it was found that players covered shorter distances than described in previous research. It was determined that the average work to rest ratio was 1:6 for the outside backs and hit-up forwards and 1:5 for the adjustables. However, the average work to rest ratios did not reflect the most demanding periods of the game; these included repeated high-intensity efforts interspersed by recovery periods of very short duration. These periods of repeated highintensity work often occurred at crucial phases of the game, where players were either attacking or defending the try-line. The patterns of movement during the repeated highintensity periods of play were different for each of the positional groups. The hit-up forwards generally sprinted short distances before completing a tackle or being tackled. The recovery durations between bouts of high-intensity exercise were generally quite short. The adjustables covered greater distances in the lead-up to the tackle and completed more lateral movements. They also had greater recovery durations between repeated high-intensity efforts than the hit-up forwards and this was reflected in a greater time spent standing, walking and jogging. The outside backs covered greater distances in the lead up to the tackle than both the hit-up forwards and the adjustables. They also had longer recovery durations between repeated high-intensity efforts than the hit-up forwards but spent less time standing, walking and jogging than the adjustables. The patterns of play revealed significant differences between the positional groups, particularly in regards to repeated high-intensity activities. It was concluded that in order to be prepared for the most highly intense periods of match-play professional rugby league players should adopt training that included the highest and lowest work to rest ratios and also included tackling. Study 2 assessed the frequency, duration and nature of repeated high-intensity efforts in rugby league using the TMA data from Study 1. Rugby league players are frequently required to tackle an opponent after sprinting to a contest. Due to the high physiological demands of contact, and it’s frequency in rugby league, the element of contact is considered to be a key component of match-play. ‘Repeated bouts of high-intensity exercise’ (HiEx) were examined in the video footage; HiEx described any period of match-play that included three or more sprints and/or tackles with a mean recovery between efforts of less than 20s. There were a number of significant (P < 0.05) differences in HiEx between the positional groups. The hit-up forwards (20.3 ± 1.5) completed a significantly (P < 0.05) greater number of HiEx bouts than the outside backs (12.0 ± 1.0). In addition, the hit-up forwards (3.8 ± 0.8) completed a significantly (P < 0.05) greater number of efforts within the HiEx bouts compared to the outside backs (3.2 ± 0.4) and the adjustables (3.1 ± 0.4). The duration of the HiEx bouts were significantly shorter for the outside backs (17.9 ± 5.4 s) compared to the hit-up forwards (24.8 ± 9.5 s) and the adjustables (21.4 ± 5.9 s). The outside backs also had significantly (P < 0.05) longer recovery periods both within and between HiEx bouts compared to the hit-up forwards and adjustables. The study identified that rugby league players complete large volumes of high-intensity work compared to athletes in other sports. It is concluded that the hit-up forwards in particular should have a significant focus placed on repeated high-intensity efforts during training. Training for all positional groups should reflect the frequency, content and duration of those HiEx bouts identified in the present study. A modified training drill was used in Study 3 to determine the physiological requirements of repeated bouts of high intensity activities and to estimate the energy costs of tackling. A cohort (n = 7) of professional rugby league players completed two test protocols. The initial six minute protocol involved three repeat sets of six sprints interspersed by a rest period of equal time to the exercise duration. The second six minute protocol involved both sprinting and tackling. The subjects were required to drive a tackle bag backwards for two metres in a standing tackle. Heart rate, blood lactate concentration and oxygen uptake data were recorded for the duration of the two protocols. No significant differences (P < 0.05) in heart rate, blood lactate concentrations and oxygen consumption were identified between the two trials, suggesting that for players required to only complete three or less repeated efforts in a single bout of high-intensity exercise (HiEx) during match-play, a running only drill during training would be sufficient to prepare them for the cardiovascular demands of competition. However, the pattern of changes over time tended to be different between trials for all measures. Further repeat efforts may have shown subsequent increases in the physiological cost of exercise for the tackle protocol compared to the running only protocol. These trends support the position that tackling places significantly greater physiological demands on players as the game progresses and when players are required to perform greater numbers of repeat sets. It is recommended that all positional groups, and especially the hit-up forwards, participate in more extensive repeat ‘sets of six’ (i.e. greater than four repeat sets) in order to prepare for the most physiologically demanding periods of match-play. Study 4 examined whether selected training drills simulated competition demands. Three in-season training drills (Ups and Backs drill, Grids drill and Game Play drill) were video recorded and compared to match-play data of equal duration from Study 1. It was found that players covered a significantly (P < 0.05) greater distance in all three training drills than for a match-play period of equal duration (with the exception of the outside backs in the game-play drill). It was also found that players spent a greater percentage of time completing high-intensity activities in all three drills compared to match-play. However, although the game-play drill most closely resembled match-play compared to the other two drills, overall none of the drills closely replicated the characteristics of match-play with regards to the match-play activities and movement patterns. As the findings from Study 3 have shown, there is a strong tendency for fullcontact to increase the physiological cost of an already high-intensity exercise drill, particularly as a function of time. The absence of, for example, tackling in the gameplay drill, may under expose players (particularly the hit-up forwards) to the highest demands of match-play. While injury prevention during training and simulated gameplay is essential and the benefits of avoiding collisions and contacts are clear, there may be value in coaches seeking to add in to game-play additional exercises that increase the physiological cost to that equivalent to the highest demands experienced in a match. This could involve, for example, static exercise against resistance or wrestling. The present series of investigations have collectively shown that professional rugby league players, particularly the hit-up forwards, engage in periods of very high-intensity exercise that often determine the outcome of critical phases of play. The data tend to support the notion that tackling, when combined with sprinting, is particularly demanding and that training may need to better prepare players for the most arduous passages of play. 2008-11-21T00:00:00Z King, Patricia Anne http://espace.library.uq.edu.au/view/UQ:186761 Early in the genesis of Mauritian Creole (MC), the quantificational determiners of its lexifier language, French, incorporated into a large number of the nouns that they combined with, resulting in the occurrence of bare nouns in argument positions, yielding (in)definite, singular, plural and generic interpretations. These early changes were accompanied by the loss all inflectional morphology, as well as the loss of the French copula, and that of the Case assigning prepositions à ('of') and de ('of') which are used in partitive and genitive constructions respectively. I argue that these changes triggered a parametric shift in noun denotation, from predicative in French to argumental in MC, and account for the fact that MC has a very different determiner system from its lexifier. My analysis is motivated by both Longobardi's (1994) claim that only DPs can be arguments, NPs cannot, and Chierchia's (1998b) seemingly incompatible claim that N can be an argument when it is Kind denoting. I provide detailed account of the emergence of the new MC determiners, from their first attestations in the early 18th century, to the end of the 19th century, when the determiner system settles into a form that is still used today. Following an analysis of the modern MC determiner system, I propose that MC nouns are lexically stored as argumental, Kind denoting terms, which share some of the distributional properties of English bare plurals, such as their ability to occur in argument positions without a determiner. The new quantificational determiners are analyzed as 'type shifting operators' that shift Kinds and predicate nominals into argumental noun phrases. The singular indefinite article enn and the plural marker bann assign existential quantification over instances of Kind denoting count nouns, and the null definite determiner is an operator that quantifies over the totality of a set. The differential behaviour of MC count vs. mass nouns is accounted for in terms of the Number argument which must be realized for common count nouns. Some seemingly 'bare' nouns comprise a phonologically null definite determiner equivalent to French le/la and English the. Subject-object asymmetry of count nouns in MC provides evidence for the occurrence of this null element which requires licensing in certain syntactic environments. The Specificity marker la, which serves to mark anaphoric definiteness, is shown to be a 'last resort' means of licensing the null definite determiner. My syntactic analysis is within Chomsky's (1995b) Minimalist framework and a Formal Semantics (Partee 1986), both of which stipulate legitimate operator variable constructions. The loss of the French quantificational determiners, and that of the copula meant that early MC lacked overt sources of quantification at both the nominal and clausal levels. In my analysis of the emerging MC determiner system, I look at the new sources of quantification that arise in order to establish the referential properties of nouns, and I show how these various strategies are linked to the means by which the semantic features of Definiteness, Deixis, Number and Specificity are expressed, and also the means by which the syntactic function of predication is realized. 2009-11-17T00:00:00Z Diana Guillemin http://espace.library.uq.edu.au/view/UQ:158691 Little is currently known about the place and meaning of physical activity in the lives of young Muslim women. The limited research that has been conducted in this area has tended to identify young Muslim women with a single (and often narrow) interpretation of Islam. This has resulted in a failure to consider the different and diverse ways in which young Muslim women shape their subjectivities through negotiating, resisting and/or taking up the different and often complex discourses within Islam. Additionally, previous research has mostly focused upon young Muslim women’s apparent barriers to physical activity engagement, often citing religious clothing and the need for gender segregation as reasons for ‘non participation’. Whilst clothing and gender segregation are important considerations for many young Muslim women, they are not necessarily relevant for all young Muslim women or have a consistent impact across Muslim women. Indeed young Muslim women living in contemporary Western society move through a variety of social spaces on any given day. Consideration therefore must be given to the to the different ways in which discourses such as gender, ethnicity, heteronormativity, healthism and popular culture intersect with the way in which young Muslim women make meaning of and engage in physical activity. Thus this thesis sought to explore the meaning and place of physical activity in the lives of ten young Muslim women as they moved across home, school, recreational spaces and their religious practices. Ten young Muslim women, who attended two different state high schools in an Australian capital city, were each interviewed seven times over a two year period. Using semi-structured interviews, the young women were asked to speak about an array of topics including physical activity, health, fitness, families, school, friends, bodies, Islam, ethnicity and popular culture. These interviews were augmented through the use of diaries, maps, photos and magazines. Whilst in this instance, concerns surrounding confidentiality prevented the diary, photo and mapping artefacts from being analysed in their own right, the discussions which were stimulated by these proved in many cases to be just as valuable. The use of these varied data collection methods however, allowed for the participants to have more freedom to tell their own stories when compared with traditional structured interviewing. All interviews were transcribed by the author and the data analysed using both an interpretive and discourse analysis. It is argued that researching young Muslim women and physical activity in postmodern times requires a flexible theoretical perspective which allows for a focus on the gendered experiences of the young participants, a complex and layered theory of difference and an understanding of how their subjectivities were constructed by social structures, power and discourse. For these reasons, feminist poststructuralism was the chosen methodology as it offered a framework and tools to assist in the understanding of how the participants negotiated discourse in order to take up different ways of understanding and engaging in physical activity (see Chapter Three). It also allowed for notions of difference and diversity. The interpretive data analysis in Chapter Four highlighted the varied ways in which all of the young women were physically active. Significantly, the family was highlighted as one of the most important access points for the young women to engage in physical activity. Religious requirements were of little consequence regarding the young women’s participation in physical education, with other factors such as gendered discourses having more of an impact on their non-participation. School sport however proved to be an important opportunity for many of the young women to be physically active in a team environment. The provisions of gender segregated spaces for the young women to be physically active was not a requirement which was spoken about by most of the young women, nor were issues to do with Islamic clothing, except when the young women spoke of others’ assumptions of how they believed clothing to impact upon their daily lives. The use of discourse analysis in Chapters Five, Six and Seven allowed for the complex intersections of physical activity with gender, race, ethnicity, religion, heteronormativity, healthism and popular culture to be explored. Indeed this analysis drew particular attention to the different and diverse ways in which the participants shaped their subjectivities and social relations in the context of physical activity and health. Chapter Five for example explored the different ways in which the participants constituted themselves as ‘young Muslim women’, supporting calls from some researchers for the need to move beyond understanding the hijab as a marker of subjectivity. Despite the re-occurring themes of difference and diversity throughout this thesis, Chapter Six highlighted the significance of dominant feminine discourses and physical activity positioning them ‘other’ than male. Additionally, Chapter Seven revealed the implications of discourses surrounding healthism on both the meaning and place of physical activity in the lives of the eleven participants. Understandings of a healthy body as being slim were expressed by many, as were the moral implications of not having the ‘correct’ body shape, with language such as ‘lazy’, ‘unmotivated’ and ‘unattractive’ used to describe those deemed to be overweight. The overall findings from this provide an important departure from much existing literature which situates young Muslim women as belonging to a homogenous group and understands their participation in physical activity through a deficit framework. The eleven participants were indeed physically active, in a variety of different ways, within a variety of different locations. Similarly the meanings which the young women ascribed to physical activity differed greatly, depending upon their access to discursive resources such as the media, education and Islam. This study points to the need for a more complex understanding of young Muslim women’s engagement in physical activity by researchers, educators and policy makers. This is particularly important in a post September 11 society where images of stereotypical Muslim women are displayed daily. 2008-11-21T00:00:00Z Knez, Kelly http://espace.library.uq.edu.au/view/UQ:106137 2007-08-24T00:00:00Z Gilmour, John Colin. http://espace.library.uq.edu.au/view/UQ:243597 2011-07-13T00:00:00Z Reid, Janet Louise. http://espace.library.uq.edu.au/view/UQ:158810 2008-11-21T00:00:00Z O'Connor, Peter Joseph http://espace.library.uq.edu.au/view/UQ:275957 This thesis presents a systematic program of research to understand and promote the mental health of Australian university students. It comprises three sections. The studies in Section 1 investigate the mental health of Australian university students. Section 2 focuses on the measurement of constructs related to the mental health of students. Section 3 consists of three interventions developed to promote the mental health and wellbeing of Australian tertiary students. Section 1 comprises five studies exploring the mental health of university students. Chapter 2 reports the prevalence of psychological distress in a university health service. This study showed that 50% of students had elevated levels of distress. Chapter 3 is a follow-up study of three health services to clarify whether the high levels of distress found in Study 1 were characteristic of a single university health service or typical of Australian university health services. This study showed similar results to Study 1 suggesting that around half of all students attending university health services have elevated levels of distress, with very little difference between students surveyed towards the end of the academic year in Study 1 and at the beginning of the year in this study. While there is a greater prevalence of distress in patients attending GP clinics in the community, the rates were higher in university clinics. Chapter 4 aimed to explore whether the prevalence rates found in university health services were similar to the general university population. This study used a convenience sample of 6449 students from three universities. This study also compared the rates of distress compared with data from the Australian National Mental Health survey data. Chapter 5 is a qualitative study investigating the issues that most affect the wellbeing of international students studying in Australia. Section 1 concludes with a study investigating the activities and challenges of counselling services in Australia and New Zealand in supporting the mental health of students. University has a number of distinguishing features that may distinguish it and its students from other populations. Section 2 comprises four studies examining four correlates of distress in university students - stress, perfectionism, coping self-efficacy, and competition. Chapter 7 describes the development and evaluation of the University Stress Scale (USS). The USS provides researchers and clinicians working with university students with a domain approach to assessing stress, which can guide interventions and appropriate referrals. Chapter 8 evaluates the factor structure of the Frost Multidimensional Perfectionism Scale in a university student sample. Chapter 9 reports a study on the relationship between perfectionism, coping self-efficacy, and student distress. Chapter 10 explores staff and student perceptions of the role competition plays in the success and distress of law students. The high levels of distress reported in studies in this thesis and confirmed with other Australian and international research provides a strong argument for a prevention approach to improve the wellbeing and resilience of university students. Universal interventions target the entire population of university students with the aim of preventing the development of mental health problems. A major component of this thesis was the development of an integrated group of universal interventions to improve student wellbeing and resilience. Staying on Track, The Learning Thermometer, and thedesk. These interventions are described in Section 3. The underlying principle for these interventions is to integrate teaching, learning, support, and wellbeing to provide a seamless experience for students. Relatively few students access support services even when they need them. To make a population impact on wellbeing and resilience, interventions need to be embedded within the curriculum and be seen as relevant to all students who want to be successful, rather than just those with mental health problems. To be successful, such an approach needs to maximise limited resources, while not creating additional burdens on academic and support staff. Staying on Track does this by focussing on providing information at a time when it is most relevant to students. The Learning Thermometer and thedesk are web-based interventions that require minimal staff input, but link students with supports and resources when needed. The Discussion and Conclusion summarises the work within this thesis and situates it within the broader context of tertiary education in Australia. It highlights some of the current challenges the sector is experiencing related to student wellbeing and possible directions for future research and intervention. 2012-06-21T00:00:00Z Helen Stallman http://espace.library.uq.edu.au/view/UQ:281251 Negative energy balance is a common metabolic condition as parturition approaches and during early lactation in dairy cows. It variably affects metabolic homeostasis and subsequently postpartum reproductive performance. Fatty liver syndrome and ketosis are two major metabolic disorders in transition dairy cows that result from the attempt by cows to respond to the energy imbalance in early lactation. Choline has been introduced to dairy feeding system basically because of its positive impact on productive parameters including milk composition, yield and postpartum reproductive function. The mechanisms by which choline is involved in metabolic pathways is not fully understood. However, there is evidence that choline has lipothrophic characteristics and contributes to the exportation of accumulated triglyceride (TG) in hepatic tissue, mostly very low density lipoprotein. Therefore, choline may have a key role in ameliorating the detrimental effects of fatty liver syndrome and ketosis in early lactation. This could be associated with improvements in postpartum reproductive function including a reduction in the postpartum anoestrus interval, higher conception rate and pregnancy rate. In the first study in this thesis, feeding 120 g/day rumen- protected choline (providing 30g choline chloride) to Holstein-Friesian cows during the transition period (3 weeks before to 6 weeks after calving) improved the metabolic state and postpartum reproductive function in dairy cows. Cows that received choline had greater plasma concentrations of leptin in early lactation and they showed a lesser decline in plasma insulin. Body condition was marginally better in cows that received choline and a greater proportion conceived to AI in the first 100 days after calving, although the latter was not significantly different to cows that did not receive choline. In the second study, Holstein-Friesian cows received 240 g/day rumen-protected choline (providing 60g choline chloride) from the time of calving to 6 weeks postpartum. Cows that received choline had lesser plasma concentration of β-hydroxybutyrate than cows that did not receive choline at Week 6 postpartum. The size of the dominant follicle was greater at Weeks 3 and 6 postpartum in cows fed choline and a greater proportion of these cows had ovulated by Week 6, compared with cows not fed choline. It was concluded that the provision of choline can influence both metabolic hormones and metabolic substrates in early lactation dairy cows and there can be beneficial effects on reproductive function. 2012-09-06T00:00:00Z Shahsavari, Arash http://espace.library.uq.edu.au/view/UQ:247244 This thesis examines the effect of welding on the microstructure and properties of commercially pure titanium welded with a pulsed laser beam. Among other applications, pulsed laser welding is widely used in the construction of dental implants from pre-fabricated wrought components and also for the repair of both wrought and cast implants. In practice these devices experience an increased number of failures due to fracture of the laser welded titanium framework compared to traditional gold prostheses. The numerous studies which have focused on improving the properties of such welds, however, tend to be more clinically focused with only limited investigations into understanding the fundamental weld metallurgy. In the present work this issue is addressed with detailed investigation into the effect of alloying elements, external contamination from welding and changing process parameters. In addition, micros tensile testing and wave-dispersive spectroscopy techniques are developed to try and improve the characterisation of pulsed laser welds. Modern wave dispersive spectroscopy techniques were successfully employed to measure bulk oxygen content in titanium on a small area 100x100m with good agreement with the bulk ASTM standard technique down to oxygen contents of 500ppm. The technique was still not localised enough however to be applied to the intended application of laser welds. An all-weld longitudinal micro tensile test was successfully developed with the ability to accurately evaluate the elongation of the welds. It was identified however that the significance of such tensile test results could not be appreciated without further investigation into the weld metallurgy to develop a greater understanding of the cause of the measured changes in properties. Investigations into the weld metallurgy revealed that alloy composition and external contamination have the most significant effect on the weld microstructure and hardness of the weld with the effect of process parameters being more subtle. The welds consist of a fusion zone and a HAZ region which has undergone significant grain growth and morphology change due to heating above the beta transus. At low alloy contents the fusion zone and HAZ undergo a massive transformation on cooling which transits to a martensite transformation with increased alloy content. Iron was found to have the largest effect on weld microstructure, being a strong suppressor of the massive phase and promoting the martensitic transformation. Oxygen and nitrogen do not affect the nature of the allotropic beta to alpha phase transformation as much as iron but have a more pronounced effect on hardness due to solid solution strengthening. The transition from massive to martensitic transformation occurs at lower alloy contents in the fusion zone compared to the HAZ due to the higher cooling rate it experiences. A wide range of process parameters were trialled with little affect on the nature of the allotropic phase transformation. The main effect of process parameters was to coarsen the microstructure due to changes in the cooling rate linked mainly to changing energy per pulse. The hardness of high solute content alloys was more sensitive to changes in process parameters than low solute content alloys due to the effect solutes have on increasing the gradient of the Hall-Petch relation. For higher pulse energy welds an additional HAZ was identified associated with slow early stage recrystallization in the alpha phase field. This region requires a large number of dislocation to form however so is only present for welds on deformed substrates. 2011-09-05T00:00:00Z Alexander Buddery http://espace.library.uq.edu.au/view/UQ:105889 2007-08-24T17:52:23Z O'Neill, Andrew. http://espace.library.uq.edu.au/view/UQ:159339 2008-11-21T00:00:00Z Milinovich, Gabriel http://espace.library.uq.edu.au/view/UQ:241539 The removal of unwanted nutrients, such as carbon, nitrogen and phosphorus from wastewater, is crucial in maintaining our waterways and preventing eutrophication. The enhanced biological phosphorus removal (EBPR) process is a widely applied and globally important biological process for the removal of phosphorus and treatment of wastewater. This removal performance occurs through the intracellular accumulation of phosphate by polyphosphate-accumulating organisms (PAO). Candidatus “Accumulibacter phosphatis” (Accumulibacter) are identified as a major PAO responsible for EBPR by culture-independent methods. Maintenance of stable EBPR performance is of importance and EBPR failure is often attributed to the presence of glycogen-accumulating organisms (GAO). Candidatus “Competibacter phosphatis” (Competibacter) has been identified as a major GAO, which competes anaerobically with PAO for carbon without removing phosphate, therefore negatively impacting EBPR performance. Typically, full-scale EBPR systems operate as floccular activated sludge, in which small biofilm aggregates (30-200 mm) of microorganisms treat wastewater. However, there is recent interest to operate activated sludge as ‘aerobic’ granules, which form larger biofilm aggregates (200-2000 mm) which exhibit faster settling characteristics and higher biomass concentrations than floccular sludge, making it operationally and economically advantageous. Phylogenetic-group specific probes for environmental samples. Since EBPR systems are mixed microbial communities, most studies are limited to in-situ investigations. The first research paper (Chapter 4) assessed the microbial community using fluorescence in-situ hybridisation (FISH). FISH is regularly used to assess the microorganisms present in EBPR activated sludge biomass, and to link process performance with resident microbial communities. This assessment has substantial implications for EBPR, specifically relating to the identification of two critical, relatively-abundant and competing bacterial populations of Accumulibacter and Competibacter. These are members of the Betaproteobacteria and Gammaproteobacteria respectively and targeted by the phylogenetic group specific (PGS) oligonucleotide FISH probes, BET42a and GAM42a. A metagenomic study of two EBPR biomasses, which produced a near complete genome for Accumulibacter, and our own 16S-23S rRNA gene analysis revealed that Accumulibacter was actually targeted by the Gammaproteobacteria PGS FISH probe. This FISH probe inconsistency was of particular importance on this occasion as the trusting use of the PGS probes would confuse the monitoring of key bacteria that have competing roles within EBPR. Granule formation mechanisms. To date, the majority of research on granular sludge has focused on optimisation of engineering aspects relating to reactor operation with little emphasis on the fundamental microbiology. The second research paper (Chapter 5) investigated microbial mechanisms for granule formation as observed in three laboratory-scale sequencing batch reactors operating for biological phosphorus removal, treating two different types of wastewater. During the initial stages of granulation two distinct granule types (white and yellow) were distinguished within the mixed microbial population. White granules appeared as compact, smooth, dense aggregates dominated by 97.5% Accumulibacter and yellow granules appeared as loose, rough, irregular aggregates with a mixed microbial population of 12.3% Accumulibacter and 57.9% Competibacter among other bacteria. Phylogenetic and microscopic analysis suggests the granule types are likely not a result of strain-associated differences, and rather the result of two different formation mechanisms. Further understanding and application of these formation mechanisms and the associated microbial ecology may provide conceptual information benefiting start-up procedures for full-scale granular sludge reactors. Bacteriophage activity causing community and performance changes. Bacteria are known to play important roles in biogeochemical cycles and biotechnology processes, such as EBPR, but little is known about the influence of bacteriophage on these processes. The third research paper (Chapter 6) investigated the effect of bacteriophage infection of EBPR process performance and granular sludge. However, a major impediment to the study of host-bacteriophage interactions is that the host bacteria and their bacteriophage are often not available in pure culture. In this study we used in-situ microbial methods to investigate a bacteriophage infection of the uncultured bacterium Accumulibacter, resulting in a decline in phosphorus removal performance and granular sludge stability within laboratory-scale EBPR treatment reactor. This is the first demonstration of bacteriophage affecting both bacterial-community structure and nutrient-removal performance in activated sludge and suggests that bacteriophage play a significant role in determining the structure and function of bacterial communities in activated sludges. Metatranscriptomic and metaproteomic comparison of floccular and granular sludge. Our understanding of the fundamental microbial mechanisms associated with granular sludge formation and stability is still very limited. The fourth research paper (Chapter 7) we present a combined metatranscriptomic and metaproteomic comparison between floccular and granular sludge and identifies significant differences in gene expression and protein. Overall, 569 mRNA transcripts and 191 proteins were identified as being statistically different between floccular and granular sludge. Results indicate that genes and proteins involved in signal transduction, cell motility, EPS formation and cell membrane biogenesis may play crucial roles in granulation. The study also identified a large number of hypothetical and unknown proteins, which may be involved in granule formation and stability, further emphasising our lack of understanding of granulation. 2011-05-30T00:00:00Z Jeremy Barr http://espace.library.uq.edu.au/view/UQ:205958 Coral disease represents one of the many challenges facing coral reefs, and is a contributing factor to the overall decline in coral reef health worldwide. An increase in disease frequency, outbreaks and the emergence of new diseases has fuelled much concern over the impact of coral diseases and subsequently prompted research into their possible causes. Our understanding of putative coral pathogens has lagged behind the emergence of coral disease as a major threat to the health of coral reefs. The Great Barrier Reef (GBR) is the largest contiguous reef in the world, and is still regarded as one the healthiest and best managed coral reef ecosystems in existence today. Despite this, the frequency of coral disease has begun to increase sharply over the past decade, prompting researchers to focus on the aetiology, causal factors and ecological impact of coral disease within the Great Barrier Reef Marine Park (GBRMP). This PhD thesis focused on two distinct disease elements: brown band (BrB) and white syndrome (WS). These two diseases affect corals within the GBRMP, yet their microbiology and ecology is largely unknown. The research project investigated the microbiology and ecology of WS and BrB affecting acroporids, using culture-dependent and independent methods to characterise the microbial community associated with healthy and diseased corals and identify putative coral pathogens. The lifecycle and diurnal cycles of BrB ciliates were also explored to gain a greater understanding of the effect of these ciliates on coral health. Ecological surveys were carried out at Heron Island sites commonly used for the collection of corals to ascertain the prevalence and significance of these diseases in the context of laboratory results. Surveys at five sites revealed a mean prevalence of 8.11% of tabular acroporids affected by WS, which is consistent with previous studies. BrB revealed a much lower prevalence of less than 0.04%. Bacterial 16S rRNA gene clone libraries were constructed from Acropora hyacinthus samples derived from a healthy control colony, and a healthy section and lesion border of a WS affected colony. Distinct shifts in the microbial community and partitioning between the lesion border and healthy section of the diseased colony were observed. In addition, the healthy section of the diseased colony displayed a different microbial community to the control colony, supporting previous data that a microbial shift occurs preceding visible signs of infection. A number of bacteria from the healthy section of diseased coral shared close sequence affiliations to a number of Vibrio spp., including potentially pathogenic Vibrio species. Sequences retrieved from the lesion border of WS affected Acropora hyacinthus were dominated by Pseudoalteromonas spp., although these species have not been previously implicated in coral disease. The coral disease BrB is characterised by the presence of a brown ciliate band and these ciliates have been identified as a new species belonging to the class Oligohymenophorea, subclass Scuticociliatia. Within BrB-affected Acropora muricata, numerous filamentous, coccoid and rod bacteria were observed to be closely associated with the ciliate band, but absent in coral tissue adjacent to the typical brown band. It is unknown whether the bacteria associated with the mass of ciliates are the primary pathogens, a food source for the ciliates or simply opportunistic pathogens. Several isolates retrieved from BrB corals were tested for their pathogenicity in controlled infection trials using Acropora muricata. The preliminary results identified at least two isolates of interest (CC1 and HB-8). However, the results of a replicated infection trial failed to conclusively identify the bacteria as the causative agents of this disease. The findings from the cross-infection trials and ecological surveys suggest that BrB is an infectious but not highly contagious coral disease. This study revealed important aspects of both WS and BrB that were previously unknown. The research carried out has built a greater understanding, and a platform for future research directed at understanding key processes involved in these coral diseases. This research has highlighted the need for ongoing infection trials in diseases, even when a pathogen has been identified. The discovery of possible key bacterial species involved in WS and BrB warrants further research aimed at understanding the mechanisms in which bacteria may affect the coral holobiont. In conclusion, this research has further supported the notion that corals are a complex community with bacterial, animal and protistan partners, which when disturbed may see one or several of the previous benign partners becoming pathogenic. In a rapidly changing climate, this conclusion is consistent with the idea that coral diseases are on the rise due to changing environmental circumstances disturbing the balance between these interdependent partners. 2010-06-08T00:00:00Z Meegan Henderson http://espace.library.uq.edu.au/view/UQ:294429 2013-03-21T17:28:48Z Mackellar, Melissa Claire http://espace.library.uq.edu.au/view/UQ:157863 The contemporary view of insect migration is one of a behaviourally distinct form of movement that is an adaptation to temporary habitats. Migratory insects are characterised by a syndrome of behavioural and physiological traits that promote migration. The migration syndromes of particular species are variations on the general syndrome, and depend on both selective pressures from the environment and the evolutionary response that is supported by the genetics of the syndrome traits. The pattern and role of migration in a particular population are determined by the interaction between the environment and the species’ migration syndrome. Complete understanding of migration in a population therefore requires a combined consideration of the population’s environment, migration syndrome and genetics. A recently developed conceptual model of a generalised insect migration system facilitates such a holistic treatment of insect migration. The model is built around four components: the migration arena (the environment); the population trajectory (the changing population demography); the migration syndrome (the traits that implement migration and determine the fitness of migrants); and the genetic complex underlying the migration syndrome. Specific variants of the model can be derived for particular species and locations. The migratory moth species Helicoverpa punctigera (Wallengren) and Helicov-erpa armigera (H¨ ubner) are widely distributed in Australia, and occur in both crop-ping and non-cropping areas. The habitats occupied by the species are often tem-porary and geographically separated. Moths colonise new habitats by long-distance migration. Both species are abundant in the periphery of the continent during summer. In winter, H. punctigera is almost exclusively confined to the far inland, whereas H. armigera mostly remains near the coast. This thesis describes the development and application of conceptual models of the migration systems of H. punctigera and H. armigera in Australia. The model for H. punctigera was used to formulate and test hypotheses on the species’ population trajectory. That for H. armigera was used to determine the effects of differences between the migration syndromes of the two species on the trajectory. The models incorporated data from empirical models and simulation models developed for selected parts of the migration systems. Bioclimatic models estimated the portion of the continent that is climatically favourable for colonisation by each species in each season. A second type of bioclimatic model estimated the effect of year-to-year variation in habitat quality on the distribution of H. punctigera breeding in the inland. Finally, a simulation model of moth migration estimated the frequency with which wind patterns support various migration pathways. For H. punctigera the portion of the continent predicted to be climatically favourable for breeding tended to cycle between the inland and the periphery, al-though, contrary to observations, central Queensland was predicted to be favourable year-round. In the far inland the winter breeding period was predicted to be sub-stantially shorter in Western Australia than in south-western Queensland. For H. armigera the potential distribution tended to expand and contract around a core area in central Queensland. The probability of H. punctigera breeding at a given site in the far inland during winter was positively correlated with the increase in vegetation greenness at the site between April and July. It was also related to soil and climate variables. Although breeding was predicted to occur more often in some areas than in others, the esti-mated distribution of breeding varied greatly from year to year, and breeding was predicted at any given site in only a minority of years. Validation analyses indicated that the migration model was sufficiently accu-rate for use in characterising the migration system. However, the limited vertical structure present in the available weather data (e.g. representing low-level jets) will prevent the model from confidently forecasting particular migration events. Complete annual cycles of the population trajectory of H. punctigera could be constructed within the limits of the migration arena and the known migration syn-drome. In eastern Australia the cycle included return migration from the eastern cropping areas to the far inland during autumn, as has previously been proposed in the literature. In Western Australia two trajectories were possible—one including spring diapause and a late summer generation in the south-west, and one including a summer generation in the far south-west. Additional trajectories were possible when pupae in spring diapause were assumed to emerge later than has been observed, or when summer quiescence was assumed to be more frequent than would be expected from our currently limited knowledge of its induction. These assumptions enabled H. punctigera to persist throughout the year in the far inland of eastern Australia, but not in that of the west. The conceptual models enabled certain hypotheses on the population trajectories to be tested with existing field and biological data. For other hypotheses they identified data that would enable testing. For a decision on which, if any, of the above H. punctigera trajectories operate in nature, we need more information on the frequency and duration of spring diapause and summer quiescence, plus additional data on breeding activity in parts of Western Australia. 2008-11-21T00:00:00Z Rochester, Wayne Allan http://espace.library.uq.edu.au/view/UQ:284675 2012-11-10T13:24:27Z Ian W. Turner http://espace.library.uq.edu.au/view/UQ:252226 This thesis is broken up into two major sections. In both sections, the mathematical tools of splines are used in different ways in the theoretical electromagnetic modelling of antennas and scatterers. Splines are well known for their data interpolation and smoothing qualities. In the first section of this thesis, the mathematics of Basis Splines (B-Splines) are “embedded” into the Method of Moments technique. Using the same B-Splines in the geometry as well as in the Method of Moments theory offers some distinct advantages that are highlighted in this thesis. Methods to increase the speed of the computations are addressed and the results are compared with those published in the literature. One conclusion from this research was that fewer wire segments were required to obtain excellent results when compared to traditional methods. The second section uses the mathematics of B-Splines to create the sophisticated geometry of conformal antennas. These antennas can now be imported into many of the modern commercial electromagnetic software packages available to produce very accurate results. From Maxwell's equations in the frequency domain, the Mixed Potential Integral Equation (MPIE) is derived. It is used with the Method of Moments technique to calculate the surface currents on a straight thin-wire. Quadratic B-Splines were used as the basis and testing functions excited from a plane wave incident electric field at different angles. A technique was introduced that entirely uses B-Spline theory to numerically solve the MPIE. This eliminated the traditional method of using conventional numerical Gauss-Quadrature integration. The difficulty with this approach was in developing an accurate analytical method from spline theory to treat the singularity in the thin-wire approximation of the Green's free-space function. When a curved wire is modelled, it is traditionally represented as a large number of straight wire segments. In this thesis, an arbitrary shaped curved wire was modelled using individually curved wire segments of unequal lengths. The same B-Splines used to represent the geometry of the curve are also used in the developed theory improving the efficiency of the code. Elliptical integrals are required to treat the singularity in the Green's free-space function and are represented as a closed form solution. Commercial electromagnetic software using straight thin-wire segments is used to model the same curved wire and the results are compared. The MPIE is then transformed into the time domain where the Time Domain Integral Equation (TDIE) is derived using the Method of Moments and spatial B-Spline basis functions. The currents on a straight thin-wire excited from an incident Gaussian pulse are calculated directly in the time domain and compared with those in the literature using pulse basis functions. Over a large bandwidth in the frequency domain, the currents are also calculated by a commercial electromagnetic software package and converted to the time domain using traditional techniques. The results from all the different methods are analysed by calculating their signature using Complex Natural Resonances (CNRs). Extracting these theoretical natural resonances showed that the inclusion of B-Splines as the basis functions to the TDIE gives a very accurate representation of the natural damped response of the induced current without additional spurious frequencies. It has been known for some time that even with the modern electromagnetic software tools available to the RF Design Engineer, it is often the inaccurate representation of the antenna/scatterer that lets them down. A modern commercial electromagnetic modelling software package has the limitation of only being able to draw shapes which are basic using the graphical front-end available to the user. The second part of this thesis concentrates exclusively on using B-Splines to produce antennas with complex geometry. The B-Splines discussed in this section are enhanced to represent the more powerful Non-Uniform Rational B-Splines (NURBS). A set of NURBS-based geometric software design tools are developed with a design procedure to present a unique set of results for different types of cylindrical and spherical conformal antennas. 2011-09-18T00:00:00Z Bruce Piper http://espace.library.uq.edu.au/view/UQ:220083 Cyclotides are topologically unique plant-derived cyclic peptides present in plants from Rubiaceae (coffee), Violaceae (violet) and Cucurbitaceae families. Their primary function in plants is proposed to be defense-related, based on their potent insecticidal activity. Members of this family of peptides incorporate the exceptional features of a head-to-tail cyclic backbone and a cystine knot motif, the combination of which imparts extraordinary stability to these molecules, and thus makes the cyclotide framework valuable for drug design applications. Kalata B1, the prototypic cyclotide which has a range of biologically important activities, including insecticidal and nematocidal activities, might potentially be a solution to the prevalence of resistance to current pesticides. To develop cyclotides as novel agricultural agents, it is necessary to understand the structural and biological basis for their reported anthelmintic activities. The aim of this thesis is to investigate the mode of action of kalata B1, which is believed to involve membrane interactions, through biophysical, chemical and biological approaches, to delineate the fundamental mechanism responsible for its nematocidal activity. The membrane-lytic properties of kalata B1 were examined using a range of biophysical techniques and reported in Chapters 3 of this thesis. Kalata B1 was shown to cause leakage of vesicle contents from large unilamellar vesicles with a preference for model membranes containing phosphoethanolamine, especially those incorporating sphingomyelin and cholesterol. Using the same dye leakage experiments, the lytic activity of a suite of alanine mutants of kalata B1 showed that substitution of residues in the well-defined hydrophobic patch of kalata B1 decreased its lytic activity dramatically. In addition, several residues responsible for the lytic activity of kalata B1 were found to cluster separately to form a bioactive patch, which was believed to be involved in a self-association step before pore-formation. Electrophysiological experiments provided unequivocal evidence of kalata B1-induced pore formation in liposome patches, and the conductive pores formed were observed to expand over time. The pore-forming propensity of kalata B1 was further confirmed using giant unilamellar vesicles (GUVs) encapsulating different molecular sizes of fluorescently-tagged dextran and is reported in Chapter 4. A representative group of three other cyclotides, kalata B2, B7 and B8, was also examined and compared with kalata B1. Kalata B2 and B7 appeared to cause dye leakage from GUVs by inducing membrane permeation similar to kalata B1, but an alternative lytic mechanism was observed from kalata B8 since total membrane disruption was observed in the presence of this peptide. The results suggested that the mode of action of cyclotides differs depending on sequence, having significant effects with surface hydrophobicity and distribution of surface charge. In Chapter 5, the effect of incorporating positively charged residues in kalata B1 on nematocidal and haemolytic activity is reported. A lysine scanning mutagenesis study of kalata B1 was conducted, where each of the non-cysteine residues were successively replaced with lysine. The suite of peptides was assayed against the larvae of two sheep nematodes, Haemonchus contortus and Trichostrongylus colubriformis. The data clearly highlighted residues that were crucial for anthelmintic activity in kalata B1. Disruption of either the hydrophobic or bioactive patches by incorporation of lysine in these regions abolished nematocidal and haemolytic activities of kalata B1, confirming that the continuity of these two patches are essential for its biological activity. Furthermore, it was demonstrated that the nematocidal activity of kalata B1 could be increased by incorporation of basic amino acids in strategic locations. The data indicated the presence of a third important face on the opposite side to the bioactive patch, since lysine substitution in this face resulted in dramatic improvement in anthelmintic activity. This face was termed the “amendable face” in this thesis. The incorporation of a lysine residue into kalata B1 enabled labelling of this peptide with biotin to help localise the molecule in the adult H. contortus nematodes following ingestion. Chapter 6 reports that a biotinylated lysine mutant of kalata B1 interacted with the lipid-rich epicuticle layer of adult H. contortus and the interaction may contribute to the death of the nematodes. The combined findings in this chapter suggest that cyclotides do not need to be ingested by the worms to exert their toxic effects, but an interaction with the external surface alone is toxic. In summary, the overall findings from this thesis show that kalata B1 is a pore-forming cyclotide, and its nematocidal and haemolytic activities can be attributed to its membrane-active properties. The observed lytic mechanisms of kalata B1 and its lysine mutants reveal that the distribution of basic residues and continuity of the hydrophobic patch on the surface of cyclotides are important modulators of their reported activities. The results from this thesis provide a mechanistic explanation for the diversity of biological functions ascribed to this fascinating family of peptides. The findings should facilitate future investigations of other cyclotide members and the development of the cyclotide framework in agricultural and pharmaceutical applications. 2010-11-09T00:00:00Z Yen-Hua Huang http://espace.library.uq.edu.au/view/UQ:105894 2007-08-24T17:52:33Z McDevitt, Christopher A. http://espace.library.uq.edu.au/view/UQ:106911 2007-08-24T00:00:00Z World, Cameron John. http://espace.library.uq.edu.au/view/UQ:205585 Sulfite oxidising enzymes are found in all forms of life and play an important role in detoxification of sulfite produced through biochemical processes. All known sulfite oxidising enzymes share a common molybdenum active site. The sulfite dehydrogenase (SDH) from the soil bacterium Starkeya novella differs from the vertebrate sulfite oxidases (SO) in that the heme and Mo subunits are tightly associated rather than connected by a flexible hinge. This structural integrity makes SDH an ideal model enzyme for the study of enzymatic sulfite oxidation without the complications of structural changes underlying catalysis. In human sulfite oxidase (HSO) the substitution of a conserved active site amino acid residue, Arg-160 for Gln, results in a lethal disease. A number of independent studies have been carried out in order to understand the effects of this substitution on catalysis in both human (HSO) and chicken sulfite oxidising enzymes (CSO). The focus of this work is the analogous residue in SDH, Arg 55. A number of active site substitutions have been investigated, including SDHR55Q, an analogous substitution to the lethal mutation identified in humans. In addition, the properties of the Arg residue have also been probed using a substitution to a hydrophobic residue, Met (SDHR55M) and a substitution to the positively charged Lys (SDHR55K). A fourth active site substitution, SDHH57A, was also investigated as the crystal structure of this variant indicated that His-57 plays a role in stabilising the position of Arg-55 in SDH. It was of interest to determine the effect of the instability in the position of Arg-55 on the catalytic parameters of the SDHH57A. The kinetic properties of the substituted enzymes were investigated using steady-state assays with cytochrome c as an electron acceptor. When the positive charge was lost in the case of SDHR55M and SDHR55Q, a dramatic increase in the KM (sulfite - app) of 2 – 3 orders of magnitude resulted. This indicates that the positive charge on Arg-55 is important for substrate binding. All the Arg-55 variants studied were found to have lower turnover numbers than the wild type, in particular, SDHR55Q was found to have a reduced kcat (108 s-1 vs 345 s-1 for SDHWT at pH 8). The changes in the Mo centre underlying the altered kinetic properties were investigated in detail using EPR spectroscopy of the intermediate MoV oxidation state in SDHR55Q and SDHH57A. Similar to what has been noted for HSOR160Q, a sulfate blocked form was observed at pH 6 using pulsed EPR experiments, suggesting that this substitution causes an inhibition of the hydrolysis step required to release the reaction product, sulfate. This could be a further reason for the poor catalytic activity of SDHR55Q, in particular, a reason for the low turnover rate of this variant. Unlike what was noted in HSOR160Q, where the substituted enzyme showed a dramatic decrease in rate of intramolecular transfer by three orders of magnitude compared to HSOWT, the rate of electron transfer was found to be 3 times faster in SDHR55Q relative to the wild type enzyme. These results indicate that Arg-55 is not involved in the pathway of electron transfer between the Mo and heme centres, but rather assists with the the docking of the heme group in HSO. As this process is not required in SDH, our results suggest that intramolecular electron transfer (IET) in HSOR160Q decreases because it is crucial for docking of the heme domain. Through potentiometric redox titrations, the effect of the active site amino acid substitutions on both the Mo and Fe redox potentials was investigated. No significant change was determined for the MoVI/V redox potentials, however, the heme potentials for SDHWT and SDHR55K were 40 mV higher than those of the other variants, with the lowest potentials belonging to SDHR55M and SDHH57A. Of further interest was that the MoVI/V couple is significantly lower than the heme couple (175 mV vs 240 mV respectively) in SDHWT. It appears that the positive charge of the Arg is important in regulating the heme redox potentials and could thereby contribute to modulating enzymatic activity. When SDH was immobilised on a modified pyrolytic graphite electrode, stable and high catalytic currents were observed, indicating facile heterogeneous electron transfer between the enzyme and the electrode. This good electron transfer allowed the catalytic properties of SDH and its substituted enzymes to be investigated as a function of potential. A pH dependence ( 59 mV/pH) in the catalytic operating potential was noted for SDHWT and SDHR55K, which appears to follow the pH dependence of the MoVI/V couple. This catalytic potential is pH-independent in the R55M and H57A variants, where the catalytic operating potentials appeared to follow the FeIII/II redox couple. It is proposed that two distinct pathways of electron transfer from the Mo centre to the electrode are likely to exist. The first is direct transfer from the Mo centre to the electrode at lower potential (~ 175 mV) while the second proceeds via the heme group (320 mV). The pathway followed is determined by the oxidation state of the heme group. A slight difference in the electron transfer rates of these two processes was seen, with direct transfer (from Mo) being the faster, which accounts for the unusual peak shape noted in the voltammogram for SDHWT at high sulfite concentrations, where the rate of catalytic activity slows at a higher potentials despite the greater thermodynamic driving force. This work provides new insights into the mechanism of enzymatic sulfite oxidation. Arg-55 has been shown to play an important role in the catalytic functioning of SDH in both substrate affinity and product release. Unlike what has been previously proposed, Arg-55 does not play a part in the pathway of electron transfer, but is rather involved in the regulation of the redox potentials of the metal centres in the enzyme. 2010-05-28T00:00:00Z Trevor Rapson http://espace.library.uq.edu.au/view/UQ:252707 2011-09-21T00:00:00Z Frazer, David Michael http://espace.library.uq.edu.au/view/UQ:211627 Brain tumours comprise about 25% of all cancers in children. Medulloblastoma – which arise in the cerebellum – are the most common and severe malignant pediatric brain tumour and the leading cause of cancer-related deaths in children under the age of 9. Treatment of medulloblastoma remains conventional, with surgery followed by chemotherapy and radiation. These measures are successful in about 60-80% of cases but treatment results in severe side effects due to its toxicity to the central nervous system. Therefore it is of utmost importance to define the signalling pathways and genetic changes involved in the formation of medulloblastoma in order to allow for better diagnosis and treatments with higher efficiency and decreased toxicity. The cell of origin for medulloblastoma is thought to be the granule neuron progenitor, a cell type arising from cerebellar stem cells of the ventricular zone. After birth granule neuron progenitors differentiate into mature granule neurons which populate the majority of the cerebellum and are crucial for its cognitive functions and motor coordination. The Hedgehog signalling pathway plays an important role in medulloblastoma generation and murine models with activated Hedgehog signalling develop medulloblastoma at high frequencies. In addition, the Notch pathway has been implicated in the generation of medulloblastoma, and interaction between the two pathways has been suggested. Inhibitors of both Hedgehog and Notch are currently in clinical trials however knowledge of possible interactions between them could lead to more effective treatment strategies. The aim of this project was to investigate the interaction of Hedgehog and Notch signalling in normal brain development and medulloblastoma. Two mouse models allowed activation of Hedgehog and inactivation of Notch signalling in granule neuron progenitors and cerebellar ventricular zone stem cells. In granule neuron progenitors canonical Notch signalling is not required and the layering and cell types of RBP-Jlox/lox;Math1-Cre cerebella appear identical to control brains. In contrast, Notch inactivation in ventricular zone stem cells with GFAP-Cre resulted in increased differentiation of stem cells into progenitor cells accompanied by an overall developmental delay in neuronal differentiation. Medulloblastoma generated by Hedgehog activation (through inactivation of the negative Hedgehog regulator Ptc1) in both cell types cannot be blocked by Notch inactivation. Furthermore, medulloblastoma of Ptc1lox/lox;RBP-Jlox/lox;GFAP-Cre and those of Ptc1lox/lox;RBP-Jlox/lox;Math1-Cre mice are identical in incidence as well as histology to the tumours in which only Hedgehog signalling is activated. This implies that even though Notch signalling plays an important role in cerebellar stem cells it is not required for the initiation and development of Hedgehog induced medulloblastoma. Therefore it may be crucial to consider the Hedgehog status of patients in order to interpret clinical data of Notch pathway inhibitors and even more importantly these results suggest that determining the Hedgehog status might be crucial before treatment of medulloblastoma patients with Notch pathway inhibitors. 2010-08-13T00:00:00Z Elaine Julian http://espace.library.uq.edu.au/view/UQ:105890 2007-08-24T17:52:25Z Crocetti, Gregory Robert http://espace.library.uq.edu.au/view/UQ:106777 2007-08-24T00:00:00Z Gratten, Jacob. http://espace.library.uq.edu.au/view/UQ:106750 2007-08-24T00:00:00Z Nir, Edward Ess. http://espace.library.uq.edu.au/view/UQ:105549 2007-08-24T00:00:00Z Williams, Nicholas P.. http://espace.library.uq.edu.au/view/UQ:209974 Abstract: This dissertation investigates the syntax and also some aspects of the morphology of Tharifith Berber (such as, the inflectional classes of nouns and the Construct State) within the Distributed Morphology framework (Halle & Marantz 1993, et al.). One of its main objectives is to demonstrate how morphology could be brought within the range of syntax. This view becomes apparent when inflectional morphemes which project in the syntax are also used to derive words. Contrary to what has always been reported, that Berber is an unquestionable VSO language, I show that Tharifith has now shifted to a Topic-Initial configurational system. This claim is based on two pieces of evidence: (1) the SVO order is preferred over VSO, (2) when the object is a clitic both the verb and the clitic are required to be in the initial position of the clause. I propose an account arguing that the two alternations instantiate a Topic-fronting phenomenon, which requires the initial position of the clause to be filled with Topic. Of interest to word order is another property displayed by some WH- complex clauses which require Verb-First. A careful analysis of the structure of these clauses reveals that this is an instantiation of V-to-C movement, also known as the verb second phenomenon (V2). While the movement to the initial position in the main clause is argued to be motivated by Topic, I show that V2 is motivated by the feature Focus which needs to be checked in C. Due to the fact that this operation is sensitive to the phonological property of the complementiser, I make the claim that discourse features, at least in Berber, should be generated at PF. Despite the fact that the subject, object and dative clitics are often grouped under the ‘clitic – banner,’ I show that the first set displays the properties of agreement markers on the verb while the other two sets are claimed to be argument XPs. The approach takes an in-depth theoretical approach to the study of clitics. In a framework where syntax operates on purely formal features, and taking on board the view that clitics as arguments have the formal features required by the computation identical to the ones found with lexical NPs, it is argued that any other distinction between the two sets of arguments is made post-syntactically. Argument structure is then claimed to follow from a fairly small number of principles which govern their syntactic system. The study discusses the movement of clitics at length, and argues it to be phonological. Crucial to the analysis is the fact that this movement operation is not only dependent on the phonological property of clitics but is also dependent on the property of functional elements that host them. Evidence is provided which shows that only functional categories that are phonologically dependent can be hosts. I then conclude that cliticisation is in fact an attraction by the host, a process which occurs during the mapping of the syntactic output to phonology. I further argue that this type of PF merger which is claimed to generate the placement of clitics is constrained by an adjacency relation. Additional support to the claim that morphology should be subject to syntactic principles is found with valency. I show that the system, in many respects, treats the structure of verbs and clauses along the same line. Furthermore, the meaning which is traditionally claimed to be inherent to words is shown from the verbal system to follow from the syntactic structure the verbs project. 2010-07-31T00:00:00Z Abdelhak El Hankari http://espace.library.uq.edu.au/view/UQ:254235 2011-10-05T00:00:00Z Bogossian, Fiona E. http://espace.library.uq.edu.au/view/UQ:274608 The Tamworth Country Music Festival is considered to be the premier event of Australia’s country music calendar and has a 40-year history. The festival has inextricably linked Tamworth to country music and has changed the cultural identity of the city, which is now referred to by many as ‘Australia’s Country Music Capital’. Despite the importance of this event to the region, little academic research has been conducted in the past with regard to the motivations, experiences and expectations of visitors who attend the festival. Perhaps more importantly, no research has been undertaken to identify the role that country music plays for those who attend the festival, and what consequences the choice of the music presented at the event may have on the individuals who attend and their experience of the festival itself. In seeking to address this research gap, a two-phase study using a mixed-method research design was undertaken during the 10-day festival in January, over a two-year period in 2008 and 2009. In order to determine visitors’ motivations for attending the event and the types of experiences they sought, the first phase of the study used a quant/QUAL approach. A total of 1320 completed surveys were collected during the 2008 Tamworth Country Music Festival. These data were analysed using SPSS 15.0 for the quantitative questions and Microsoft Excel for the sorting and coding of the open-ended qualitative questions. The findings revealed that country music and the festival atmosphere were the principal motivators for many who attended the Tamworth Country Music Festival, although this phase of the study did not reveal why these festival attributes were so important to the study participants. The findings from Phase 1 of the study were then used as a basis to develop an interview schedule that was used in a series of in-depth qualitative interviews with 29 attendees at the 2009 festival. The qualitative data that resulted from this second phase of the study were analysed using the Leximancer 3.1 software program, which transformed the data from natural language into semantic patterns, which were listed and mapped to enable easy identification of the major themes from the interviews, as well as the relationships between them and the major concepts within the data. This information was then further analysed and interpreted by the researcher. The principal findings from the interview data were that a majority of visitors were motivated to attend the Tamworth Country Music Festival because of its focus on country music. The atmosphere, the social aspects and the Australian character of the festival were also important motivators for attendance; however, the study found that each of the different aspects of the festival was highly influenced by the country music genre. Furthermore, the study found that visitors to the festival attributed a broad range of associated meanings to country music, including those related to a particular way of life. The findings indicate that the Tamworth Country Music Festival experience is a complex phenomenon, as it is a process of constant co-occurrence between the visitor and the provisions offered by the organisers, as well as an important social and cultural exchange with the other visitors who attend the festival. The results of this study have provided a useful insight for planners, organisers and managers of the festival who, by channelling their resources into the areas that really matter to visitors, will be positioned better to maintain their current competitive advantage for future festivals. 2012-05-23T00:00:00Z Rosemary Adsett http://espace.library.uq.edu.au/view/UQ:225688 Friedreich’s Ataxia (FRDA) is an autosomal recessive neurodegenerative disorder and the most common of the hereditary ataxias. Pathological degeneration primarily involves the spinal cord with the degeneration of neurones in the spinocerebellar tracts. Dysarthria is a diagnostic clinical feature of FRDA. While the dysarthria associated with FRDA is classically described as ataxic, neurological involvement can extend beyond the spinocerebellar tracts, particularly as the disease progresses, resulting in a mixed dysarthria. The current keystone of knowledge regarding the dysarthria associated with FRDA has arisen largely from perceptual descriptions. Hence, the primary aim of this thesis is to provide a comprehensive assessment of speech function in individuals with a confirmed genetic diagnosis of FRDA, applying perceptual and instrumental techniques. Thirty-eight individuals with FRDA participated in the perceptual speech assessment with a subgroup of seven participants completing an instrumental battery of assessments. Perceptual speech assessment was conducted on the cohort of 38 individuals with FRDA and a group of 20 non-neurologically impaired individuals, who served as controls. Assessment included the perceptual analysis of a speech sample investigating 30 different dimensions of speech, an overall dysarthria severity rating, and the Assessment of Intelligibility of Dysarthria Speech (ASSIDS). The FRDA participants presented with dysarthria of severities ranging from mild to moderate. Correlation analysis revealed a significant relationship between dysarthria severity and parameters of disease duration and overall disease severity, but not with age of onset or the size of the genetic mutation. The perceptual profiles obtained from the perceptual analysis were subjected to a cluster analysis, suggesting the existence of three subgroups, defined according to their perceptual speech characteristics. The first subgroup presented with mild dysarthric symptoms, the second was characterised by the presence of hypernasality and the third distinguished by an increased phonatory dysfunction. A subgroup of seven individuals with FRDA participated in a series of instrumental assessments, including acoustic and physiological measures (Nasometer and Respitrace), selected to provide an overview of motor speech function encapsulating all aspects of speech production including: articulation, phonation, resonance and speech breathing. Instrumental assessment supported the perceptual findings and the clustering of subgroups, representing distinct impairments of the speech mechanism and perhaps reflective of differing evolutions beyond the cerebellum. A further aim of this thesis was to specifically investigate the articulatory impairment that is prominent in the dysarthria associated with FRDA, using physiological instrumentation. Electropalatography (EPG) was used to describe the pattern of linguopalatal contact and the consonant phase durations exhibited by seven individuals with FRDA. The FRDA group exhibited significantly increased consonant durations compared to the controls while maintaining normal linguopalatal contact patterns, suggesting that the articulatory impairment in FRDA manifests as a temporal rather than spatial disturbance. Lingual kinematics were investigated in two subsequent studies using electromagnetic articulography (EMA). Due to the demands of the assessment, a smaller group of four individuals with FRDA participated in the study. The first study investigated lingual movements across sentence productions of the tongue–tip sentence Tess told Dan to stay fit and the tongue-back sentence Karl got a croaking frog. Kinematic parameters included velocity, acceleration/deceleration, distance travelled and duration of movement for the approach phase and release phase of consonant productions across the sentence. The FRDA group demonstrated greater movement durations, increased articulatory distances and reduced speed measures during the approach phase of consonant productions. The final EMA study sought to further investigate the articulatory kinematics in the dysarthria associated with FRDA, by looking specifically at the production of the alveolar consonant /t/ and the velar consonant /k/ as produced within a sentence utterance, as well as in a syllable repetition task. Results revealed significantly greater movement durations and increased articulatory distances, most predominantly during the approach phase of consonant production. A task difference was observed with lingual kinematics more disturbed during the syllable repetition task than during the sentence utterance. Despite expectations of slowed articulatory movements in FRDA dysarthria, the EMA data indicated that the observed prolongation of consonant phase durations was generally associated with greater articulatory distances, rather than slowed movement execution. Slowed movement execution was evident only in the participant who presented with a more severe dysarthria, associated with a more severe disease progression. This thesis provides the largest study of the dysarthria associated with FRDA to date. It is anticipated that this research will provide a baseline for a longitudinal study of speech function in FRDA. The quantification of speech function in this population may have an important role in providing a significant functional measure of neurological decline. This may lead to the development of more sensitive assessment tools to measure change in performance in clinical trials, for determining the benefits of speech pathology interventions and for therapies targeting the central nervous system (CNS) involvement in FRDA. 2010-12-21T00:00:00Z Joanne Folker http://espace.library.uq.edu.au/view/UQ:284087 2012-10-30T00:00:00Z Stephens, Christopher John. http://espace.library.uq.edu.au/view/UQ:286812 2012-12-06T10:49:01Z Spearritt, Gordon D http://espace.library.uq.edu.au/view/UQ:106595 2007-08-24T00:00:00Z Kabir, Nahid Afrose. http://espace.library.uq.edu.au/view/UQ:106764 2007-08-24T00:00:00Z Piscioneri, Matthew. http://espace.library.uq.edu.au/view/UQ:205495 Ultrasound has become a widely available imaging modality for the investigation of patients with a variety of clinical conditions. Concerns have been raised by clinicians and government alike that a sizeable proportion of this imaging may be unnecessary, inappropriate or of inadequate quality for patient management. This study aims to prospectively evaluate the opinions of treating vascular clinicians as to whether the vascular ultrasound imaging studies that patients bring with them when initially referred are necessary, and technically adequate to permit clinical decision-making for the patient’s management. Vascular clinicians Australia-wide were invited to participate in the study in April 2003. They were asked to recruit their next 50 consecutive new patients, eligible to be enrolled in the study, who presented with ultrasound scans organized by their referring doctor. The clinicians were asked to fill out a two-page proforma detailing the diagnosis, if known, and their opinion regarding the study and report, whether they required further information, and what investigations they would have ordered if seeing the patient for the first time, in a primary setting. 17 vascular clinicians Australia-wide agreed to participate in the study and to recruit their next 50 patients referred to them with vascular ultrasound imaging performed prior to specialist consultation. 473 Proformas were returned for analysis. Of all studies performed, 19 percent were judged unnecessary. Studies that were considered necessary however, were, in some cases, technically inaccurately or inadequately reported in 27 percent of cases, and 67 percent of these studies were then repeated. The NATAVUS Study has demonstrated that a significant percentage of ultrasound imaging performed by referring clinicians to vascular specialists is unnecessary, and that necessary imaging does not, in a large percentage of cases, provide accurate and adequate data to allow for specialist clinical decision-making. The data from this study has the potential to develop guidelines for appropriate use of vascular ultrasound imaging for various vascular conditions. If the results of this study were to be duplicated in a larger study, development and adoption of such guidelines would have the potential to generate significant cost savings to the health system by the elimination of some unnecessary testing. This is of particular relevance with Australia’s ageing population. 2010-05-23T00:00:00Z Rebecca Jack http://espace.library.uq.edu.au/view/UQ:205299 Support teachers learning difficulties (STLD) have made a significant contribution to the provision of support for students experiencing learning difficulties and learning disabilities in Queensland state primary schools over almost forty years. During the 1990s with the implementation of an inclusive curriculum in schools, and in recent years, with changing systemic expectations of how academic performance might be improved, these teachers have increasingly participated in collaborative models with their classroom colleagues to provide for students experiencing various barriers to learning. This study focuses on the nature of exemplary practice as perceived through the eyes and voices of six exemplary STLD teachers. In keeping with this intent, a process of selecting the participants for in-depth study was instigated in a professional community of state primary STLD teachers located in a Brisbane education district to determine at the grass-roots what an exemplary STLD teacher might “look like”, and which six teachers in that community might contribute to the community‟s understanding of exemplary STLD teaching practice. These contributions are represented in six case studies, referred to as “portraits” and were co-constructed, that is through a dialogic process between the participant and me. Each portrait communicates an aspect of teaching practice and the experiential knowledge that underpins it. The term “exemplary” has been adopted consciously to denote “that serves as an example” (Harper, 2001) in contrast to the term “expert”, which frequently carries a technical connotation. A mixed methodology was adopted (Lincoln & Guba, 2003) in this qualitative study in anticipation of the need to draw upon various methods that in combination might assist in viewing, conceptualizing and harnessing the dynamic complexity expected to be evident in grassroots practice. First, various expressions of constructivism contributed, with the major influence being social constructivism to denote a “house” or a community of professionals in ongoing dialogue. 6 This provides the framework within which the study has been undertaken. Second, phenomenology, most particularly the work of Moustakas (1994) and van Manen (1990, 1994, 1995, 2007), is the primary source for the inspiration (van Manen) and the methods and tools (Moustakas) to explore the nature of their practice. Phenomenological approaches were adopted with the expectation they could assist in highlighting the essence of each individual‟s practice while allowing for the eliciting of experiential themes that are of importance to the professional community of STLD teachers. Finally, studies of practical teacher knowledge (Elbaz, 1983) in association with narrative inquiry (Connolly & Clandinin, 1988) have provided further insights into how the collective expression of these teachers might be displayed. The primary preoccupation of the portraits is the teachers‟ provision of support for individual students, and the nature and quality of the relationships enlisted in the service of making this provision. The teachers‟ transactions on behalf of these students are indicative of a raft of values, ideals, collaborative and communication skills which might be subsumed by the term relatedness, and the ability to see astutely the elements in various situations that need attentiveness. Their practice in action appears to be best encapsulated by Van Manen‟s (1995) term “pedagogical tact”, a term borrowed to capture the nature of the pedagogical relationships infused into their personal and professional selves. Three views of practice are provided to display and illuminate the nature of the six exemplary teachers‟ collective practice – View 1: “From the inside” which reveals the metaphors that inhabit their practice and the significance they have for their practice; View 2: “From the outside” which, through the vehicle of a narrative highlights a STLD teacher and a classroom teacher undertaking a collaborative process of providing for Dayne a student experiencing significant difficulties; View 3: “Thinking together” which provides an edited script elicited from a conversation of the participating exemplary STLD teachers. Collectively, the three views reveal what is at the heart of learning support for the six teachers. In addition, aspects of practical knowledge that are particularly pertinent to learning support practice are discussed. 7 Finally, the effectiveness of the methods adopted for the study is explored. First, the screening process successfully enabled the selection of participants who had developed their craft to a sophisticated degree enhanced by their own “personal signature” (Eisner, 1991). Second, the adoption of a combination of a social constructivist framework and phenomenological approaches provided appropriate vehicles to enable the construction of six portraits of practices that exemplified significant aspects of practice. Third, the difficulties of authenticating the portraits using a cohort of critical friends from the STLD community and forging links with the community are discussed. Finally, I raise the possibility of embedding the portraits in professional development contexts where early career STLD teachers may wish to reflect on their practice. 2010-05-17T00:00:00Z Michael Boyle http://espace.library.uq.edu.au/view/UQ:107072 2007-08-24T00:00:00Z Purcell, Anne http://espace.library.uq.edu.au/view/UQ:241528 While the UPOV Convention is the central international intellectual property treaty dealing with plant varieties, it has attracted comparatively little attention. To the extent that there has been discussion of the UPOV Convention, it has been characterised by the fact that most scholarship in this area has focused on specific national or regional implementation of the UPOV Convention. Furthermore, a number of assumptions are commonly made in the scholarship on the UPOV Convention and UPOV-based schemes including that UPOV is sui generis; that it is out-dated and obsolete; and that the UPOV Convention has increasingly come to resemble patent protection. To contribute to, and move beyond, this scholarship this thesis has two interrelated aims. These are: (1) to explore historically some of the key ideas, aspects and concepts that underpin and inform the UPOV Convention; and (2) to critically engage with the assumptions commonly made about the UPOV Convention. While the thesis does not engage directly with normative or doctrinal inquiries, this kind of historical analysis is important as the UPOV Union and the UPOV Convention are at an important juncture, with unresolved questions over the effectiveness of the Convention, as well as over the relevance of, and need for, a separate international treaty on plant varieties. By highlighting the changes that have occurred over the past fifty years, as well as the actors involved in these changes, the thesis uncovers the relational, interactive and juridical nature of the UPOV Convention; suggesting a more mobile and mutable law than has previously been discussed. As a consequence those involved in UPOV — including the UPOV Union, member states, plant breeding organisations, non-government organisations, other industry bodies and academics — must clearly and explicitly acknowledge the relational, interactive and juridical nature of the UPOV Convention. Indeed, it can no longer be assumed that the UPOV Convention is simply sui generis, out-dated and patent-like. 2011-05-30T00:00:00Z Jay Sanderson http://espace.library.uq.edu.au/view/UQ:276411 Naming deficits are commonly experienced post-stroke and, given their high incidence and detrimental consequences, these impairments are frequently targeted in the treatment of aphasia. Evidence suggests that certain techniques can facilitate naming in aphasia, however, the neural mechanisms underpinning training-induced success remain unclear. This thesis aimed to advance our understanding of the mechanisms responsible for naming facilitation in the unimpaired brain and, importantly, to elucidate the neurocognitive substrates of naming facilitation in aphasia. Further, it aimed to determine whether such effects differ based on the type and timing of prior facilitation. The functional magnetic resonance imaging (fMRI) studies forming part of this thesis achieved these aims by utilizing two targeted language tasks that have been demonstrated to be effective facilitation techniques in individuals with aphasia. The level of processing required (either at the semantic or phonological level) in each language task was deliberately manipulated and allowed investigation of the potential locus of any positive effects upon subsequent naming performance. By manipulating the timing of prior facilitation using these tasks, either over the short-term (a period of minutes) or the long-term (a period of several days), the studies were also able to investigate the longevity of any facilitation effects. To our knowledge, no other neuroimaging studies have utilized this design to explore the underlying mechanisms involved in successful overt picture naming following facilitation, with targeted tasks over different timeframes, in individuals with aphasia and healthy controls. The thesis is comprised of four studies: semantic and phonological facilitation studies in both healthy individuals and in aphasia. The semantic studies investigated the behavioural and neurocognitive effects of naming facilitation using a semantic task in the absence of the phonological word form, and the time course of such effects. One experiment using this facilitation technique was conducted upon healthy controls and a second experiment, using exactly the same technique, was conducted upon individuals with aphasia. Although both subject groups benefited behaviourally from facilitation with a semantic task, different patterns of neural activation were evident. Modulation of activity was identified within regions associated with lexical-semantic processing, over the long-term for controls and over both the long- and the short-term for participants with aphasia. However, short-term facilitatory effects for control participants were found in regions linked to episodic memory and object recognition mechanisms. The phonological studies explored the effects of naming facilitation from a phonologically-based auditory repetition task administered in the presence of a picture. An experiment using this technique was conducted with healthy controls and a separate experiment with individuals with aphasia. Greater positive behavioural effects were shown in this phonological study than in the semantic study, for both controls and participants with aphasia. Additionally, the neuroimaging results suggested that the facilitatory effects arising from a phonological task were less selective, engaging regions associated with phonological and semantic processing in both controls and individuals with aphasia. For both subject groups these effects were evident over the long- and the short-term, with the short-term effects for control participants contributed to by modulation of activity in an area known to be involved in phonological processing. In summary, both techniques were effective in facilitating subsequent picture naming in controls and participants with aphasia to varying degrees. Taken together, the facilitation effects of a semantic verification task appeared to be somewhat selective in engaging regions associated with more efficient lexical-semantic processing during subsequent naming. On the other hand, an auditory repetition task was slightly more effective and less selective, engaging regions linked to both semantic and phonological processing, consistent with a strengthening of the connections between the two levels of processing. Although no distinct patterns emerged across individuals with aphasia regarding broader mechanisms of recovery, the results did provide evidence that right hemisphere mechanisms may be supportive of naming facilitation rather than maladaptive, and highlighted the involvement of regions not traditionally associated with language processing, particularly the cerebellum. Together, these experiments suggest that distinct neurocognitive mechanisms underlie the facilitation of naming by semantic and phonological tasks in both subject groups. An advance in our understanding of these mechanisms will inform the therapeutic facilitation of naming in the recovery of word production abilities following neurological injury. Therefore, these findings may aid the development of theoretically driven treatment selection methods and ultimately result in the provision of more targeted therapy for individuals with aphasia. 2012-06-27T00:00:00Z Shiree Heath http://espace.library.uq.edu.au/view/UQ:194264 West Nile Virus (WNV) has emerged as a major cause of viral encephalitis. Since its outbreak in the United States 27,000 people have presented with clinical WNV disease resulting in 1074 fatalities. WNV causes a range of disease from mild febrile illnesses to severe and fatal encephalitis. To date, there are currently no therapeutic agents or vaccines available to treat WNV infection in humans. In order to address this, a better understanding of the mechanisms responsible for viral neuroinvasion and neuropathology are required. Using a range of in vitro and in vivo studies, we have investigated the routes by which WNV enters the CNS. Virus replication was observed in the brain microvascular endothelial cells in mice that succumbed to WNV encephalitis. Moreover, we demonstrated that infection of a polarized HBMEC with WNV induced apoptosis. Microarray analysis of WNV-infected HBMEC’s revealed that WNV elicited the expression of cytokines that have been shown to contribute to permeablization of the BBB. These findings suggest that WNV can enter the CNS through the BBB via multiple mechanisms. Real-time RT-PCR performed on WNVinfected HBMECs identified two host genes involved in the host cellular anti-oxidant response that were differentially regulated during viral infection. Furthermore, the addition of the antioxidant, N-acetylcysteine, restored cell viability and decreased viral replication, indicating that oxidative stress contributes to WNV-induced pathogenesis. The current state of knowledge regarding the pathogenesis of WNV encephalitis is based on studies that have defined the role of systemic immune responses to WNV. Limited investigations have been undertaken to determine the contribution of brain cells in the defence, or damage to the brain once WNV has gained access to the CNS. Real-time RT-PCR results in conjunction with in vivo CBA assay data, suggested several candidate host genes that could contribute to the pathogenesis of WNV. Thus, it is necessary to further define the mechanisms of WNV induced pathogenesis as this will aid in the development of targeted strategies to prevent neurological infection and mitigate neurological diseases in affected individuals. 2010-01-30T00:00:00Z Rebecca Biron http://espace.library.uq.edu.au/view/UQ:106367 2007-08-24T00:00:00Z Redden, Guy Francis http://espace.library.uq.edu.au/view/UQ:291271 2013-02-12T12:27:27Z Nguyen, Tai Minh