UQ Theses Collection (RHD) - UQ staff and students only - UQ eSpace

The Application of Spices and Herbs to Control Food-borne Pathogens in Ready to Eat Shrimp

Nimsha Weerakkody — 2011-12-10T00:00:00Z

Abstract An interest in antimicrobials from new sources has expanded in recent years because of greater consumer demand for healthy foods with natural preservatives instead of chemical preservatives. Undetermined antimicrobial and antioxidant properties of novel or less-utilised spices and herbs may have the potential to fulfil consumer demands. Numerous studies have reported the antimicrobial activity of individual essential oils or plant extracts alone, however only a few have reported on the activity of combined spice and herb extracts. In addition, there is lack of knowledge on the mechanism of antimicrobial activity of spice and herb extracts. The overall aim of this study was to investigate the antimicrobial activity of less well known spices and herbs against food-borne pathogens Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, Clostridium perfringens and Staphylococcus aureus. In total, seven herbs and spices including the less-utilized goraka (Garcinia quaesita), galangal (Alpinia galanga), lemon iron bark (Eucalyptus staigerana) and mountain pepper (Tasmannia lanceolata) and the more commonly used pepper (Piper nigrum), rosemary (Rosmarinus officinalis), and oregano (Oreganum vulgare) were extracted using ethanol, water and hexane solvents. The antimicrobial activities of these extracts were tested using disc diffusion and broth dilution assays. The total phenolic content of spice and herb extracts was assayed to establish any relationship between antimicrobial activity and phenolic compound levels. Solvent type greatly influenced the antimicrobial activity of the spice and herb extracts except for those of pepper, which had little or no activity. In particular, the hexane and ethanol extracts of galangal and ethanol and water extracts of lemon iron bark had strong antimicrobial activity against S. aureus and/or L. monocytogenes. Antimicrobial activity and phenolic compound levels was found to poorly correlated (r2< 0.30), in contrast to that found by others. This indicated that the antimicrobial activity in some herb and spice extracts may be due to the presence of substances other than phenolic compounds. Three spice and herb extracts yielding the best results were selected for synergistic antimicrobial activity studies using broth dilution assay followed by viable counts. The chemical compositions of these extracts were determined using gas chromatography-mass spectrometry (GC-MS) analysis to provide further insight into antimicrobial constituents and their potential mechanism(s) of action. Combinations of galangal with either rosemary or lemon iron bark showed synergistic antimicrobial activity. Specifically, galangal and rosemary showed synergistic activity against S. aureus and L. monocytogenes only, while galangal and lemon iron bark showed synergistic activity against E. coli and S. Typhimurium. The major chemical components of the galangal and lemon iron bark extracts were 1'-acetoxy-chavicol acetate (1'ACA) (63.4%), and neral (15.6%), respectively, while 1,8 cineole (26.3%) and camphor (20.3%) were identified as major chemical components of the rosemary extract. Previously works by others have shown that crude galangal extract causes cell leakage and coagulation of cytoplasmic components. This part of the project focused on determining if 1'ACA was the galangal extract component which caused membrane damage and if so what effects it has on cell morphology, membrane fatty acid composition, stress response and virulence gene expression and mutation rate. The major chemical compound of the galangal extract (1'ACA) was purified to 100% and was shown to possess antimicrobial activity against S. aureus (including methicillin resistant strains) and L. monocytogenes, but little activity against E. coli and S. Typhimurium. The mechanism of action of purified 1'ACA against the most sensitive bacteria was investigated using different methods. Scanning electron microscopy showed that 1'ACA caused S. aureus cells to develop a rough surface and appear damaged or deformed. An increase in levels of cytoplasmic constituent release and a higher molar fatty acid unsaturation index (due to the changes of ratio of saturated to unsaturated fatty acids) provided further evidence of the effect of 1'ACA on cell envelope integrity. Significant up regulation of genes responsive to cell wall (msrA, vraS) and membrane damage (vraD) were identified using reverse-transcriptase quantitative polymerase chain reaction. Furthermore, a significantly higher mutation rate was observed in S. aureus exposed to 1'ACA. The results of this study suggest that the S. aureus cell envelope is the principal target for the microbicidal action of 1'ACA, either directly or indirectly. Lastly the use of synergistic herb and spice extract combinations in controlling pathogens and food spoilage bacteria in vacuum packed ready-to-eat (RTE) shrimp was investigated. A combination of galangal, rosemary and lemon iron bark significantly (p<0.05) reduced levels of aerobic bacteria and lactic acid bacteria at 4oC on day 12 by 1.6 and 1.59 log cfu/g, respectively. By day 16, levels of these bacteria were equivalent to controls. This spice and herb extract combination treated shrimp had significantly (p<0.05) lower lipid oxidation from days 4 to 16. Similarly, a combination of galangal and rosemary extract significantly (p<0.05) reduced levels of aerobic bacteria and lactic acid bacteria at 8oC on day 8 by 2.82 and 2.61 log cfu/g, respectively. By days 12 and 16 these levels of these bacteria were equivalent to controls. This spice and herb combination treated shrimp had significantly (p<0.05) lower lipid oxidation on days 4 and 16. None of the spice and herb extracts combinations had an effect on levels of inoculated L. monocytogenes or S. aureus, despite having significant activity in vitro. The reason for this is not clear, but possibly due to the more complex environment found in a food matrix. No changes in the colour or pH of shrimp during storage with the spice and herb extract combinations were found. Spice and herb extract combinations used in this study possessed the ability to control the growth of spoilage microflora and extend the shelf-life of RTE shrimp during the storage. Overall, this research has identified and provided a greater understanding of potential novel herb and spice derived antimicrobials for use in food or medical applications.

The application of surface electromyography for the assessment of cervical flexor muscle dysfunction in patients with neck pain

Falla, Deborah — 2007-08-24T00:00:00Z

The architectural implications of Warlpiri jilimi

Keys, Catherine Ann — 2013-06-12T10:47:15Z

THE ARCHITECTURE OF RED CEDAR, Toona ciliata M. Roem AND ITS MODIFICATION BY THE CEDAR TIP MOTH, Hypsipyla robusta Moore (Lepidoptera: Pyralidae) – A VIRTUAL MODEL -

David Spolc — 2012-06-11T00:00:00Z

ABSTRACT Red cedar, Toona ciliata (M. Roem) and its relatives, the mahoganies and tropical cedars of the Swietenioideae (Meliaceae) are highly sought after timber species inhabiting the old and new world tropics. While interest in establishing plantations is high, efforts to date have failed because larvae of the Hypsipyla spp. moth destroy the growing shoots, resulting in increased branching and poor form. Red cedar is the host of the cedar tip moth, Hypsipyla robusta Moore throughout most of its range, which includes Australasia and the western pacific. It reaches over 40m in height when mature, with a spreading crown, long pinnate leaves and a buttressed trunk. It is an early successional tree, with a very high growth rate, favouring wide forest gaps. While there are many studies assessing attack by Hypsipyla spp. on their respective hosts, far fewer studies exist on the response of the Swietenioideae to attack. Studies to date have focused on tree height, branch number or basic biomass partitioning. This thesis is the world’s first model of tree architecture in the Swietenioideae, including damage from Hypsipyla spp. attack. All experiments were conducted in South East Queensland, Australia over three summer/autumn seasons, lasting three, eight and eight months respectively. In the first season, unmoderated tip moth attack and red cedar regrowth were monitored for 70 days in full sun. Treatments included wild tip moth damage, mechanical stem decapitation and undamaged controls. Feeding behaviour, levels of borer attack, stem tissue killed and regrowth branch numbers were all recorded. An allied experiment used damage in 20 greenhouse trees to assess resistance induction against future larvae establishment. All treatments, including controls gained secondary branches at statistically the same rate, stabilising at 9.3 branches per plant. Tertiary branch numbers were quite variable, likely a factor of stem damage timing and oviposition. No regrowth differences between mechanical and insect damage were recorded, suggesting no growth stimulation from insect feeding. Environmental stress appeared to exert some suppression on branching. Sap exudate in the greenhouse and gallery resin outdoors suggested resistance to be the preferred mode of defence under stress. No induction effect was found from pre-feeding. In the second and third seasons, the development rules for red cedar were derived from repeated growth measurements of trees in a greenhouse and a dedicated plantation. In the greenhouse, secondary and tertiary growth responses to two levels of larval damage were recorded over two eight month periods, using a digitiser. In the plantation, growth responses to managed larvae and mechanical damage were recorded under full sun and 70% lateral shade for two eight month periods, using plant mapping. Up to six regrowth branches were produced adjacent to the damaged tip in all greenhouse and field damage treatments, with three being the most common. There was no significant difference in branching rates between the two larval infestation rates in the greenhouse or between larval and mechanical treatments in the field (within each light treatment). But, node and leaf morphology were distinctly different between field light treatments. In the greenhouse, control plants produced no branches. In the field, full sun controls produced up to 8.5 branches from low on the stem, while lateral shade controls produced less than one lower branch. Leaves were determinate and produced from 1 to 17 leaflet pairs, as a function of stem or branch node. Leaflet size was a function of light, number of leaflet pairs and position on the rachis. Formulae describing the growth trends of stems, branches and leaves in 3D were then derived from the growth data and incorporated into sets of stochastic L-systems. L-systems were conceived by Aristid Lindenmayer as a formal language for the mathematical description of the development of cellular structures, such as the branching architecture of plants. The L-systems are animated as ‘Virtual Models’ written in the cpfg language through the L-Studio 54 interface. A greenhouse model, a lateral shade field model and a full sun field model are presented. They are largely to serve as future research tools, but have been utilised here to assess the diurnal light interception efficiency of the natural stem phyllotactic angle versus near alternatives, in both branched and unbranched architectures. Results show that the natural angle is the most efficient and this is discussed in terms of biological, physical and pest influences. Finally the field shade model is used to demonstrate a possible mechanism for producing a straight trunk tree in a forest gap, under a regime of probabilistic tip moth attack and stochastic regrowth branching. The tree is grown for 10 years, ending in an approximate canopy. Finally, a hypothetical integrated scenario for the growth of red cedar is presented as an adaptive compromise to a changing physical environment, within a gradually closing forest gap and a trade-off between height gain and losses to the cedar tip moth.

The Arc quenching properties of fine bore tubes

Fraser, Stewart Garth. — 2010-09-20T00:00:00Z

THE ART OF MYSTICISM : An Inquiry into the Notion of Ineffability in (Cataphatic) Mystical Experience

Martin, Paul Christopher — 2008-11-21T00:00:00Z

One of the defining characteristics of mystical experience posited by the psychologist and pragmatist philosopher William James in 1902 is that of ineffability, or indescribability. In this thesis my aim is to inquire into this notion of ineffability, indeed to problematize its understanding, by relating it to concepts of art and aesthetics. It is a preliminary attempt to apply the terminology of these fields in a direct analogous way to the mystical state. In short, I want to demonstrate that the mystical experience is like an artistic and aesthetic experience, in its phenomenology and psychology. My focus is on western Christian mysticism. Initially, I shall clarify my approach as dealing mainly with cataphatic, or positive mystical experience, as against apophatic, or negative mystical experiencealthough the demarcation cannot be absolute since there is a dialectical relationship between these particular modes. I introduce the terms happenstance consciousness and desire-laden consciousness, which roughly correspond to nature mysticism and theistic mysticism. The spiritual perception of God can be understood in terms of a metaphorical transposition of the mundane perception that is ordinarily involved with cognition of the world, and in this respect I appeal to the idea of the spiritual senses. I posit a distinction between the awareness of divinity, as the perceptual event, and the consciousness of divinity, as the imaginary experience, although acknowledging that it can only be a relative one. In positive (cataphatic) mystical consciousness, the imagination is of profound importance, as a means for realizing the presence of God; and accordingly, I shall survey ancient and modern thinking on the role of imagination and phantasy up to the eighteenth century. The work of Immanuel Kant in his Critique of Pure Reason (1781/87) presages a shift to non-imagistic propositional thinking about consciousness, one in which the imagination is a productive mechanism that works in conjunction with the understanding to make a judgement based on (empirical) experience. I interpret Kant analogically and metaphorically in order to argue that the mystical encounter with the noumenal God involves a perception of divine light by the sensible intuition of the soul, by dint of the spiritual senses, which is then represented phenomenally in the imaginary, and realized as the presence of God. This constitutive judgement means that the consciousness of divinity is available to be enunciated, and in that regard it demonstrates a recognition of Gods presence. In the event of contemplating God mystics are intuitively drawing the outline of divinity (circumscribing the rounded light of divinity), and in this way the invisible God is pictorially represented in the mystical imagination, where it is coloured by the understanding. Divinity is painted on to the canvas of the soul. It is a work of art, and the result of a creative enterprise. As painted by means of the light of God, the divine presence is perspectivally realized, compositionally formed, and colourfully relieved by the mystical imaginary. The experience of Gods being can finally be rendered as a tangible artwork, which is to say, enunciated, through the act of speaking and/or writing. One of the hallmarks of mystical consciousness is the sense of the beautiful and sublime nature of divinity. Utilizing Kants Critique of the Power of Judgement (1790/93) I argue that the consciousness of divinity is tantamount to an aesthetic realization, and it is by virtue of the reflecting power of judgement that mystics are able to discern the presence of God. Further inquiry reveals that mystical experience as it is realized by an affective consciousness has some affinity with twentieth-century theories of aesthetic experience. Phenomenologically, the imaginary presence of God is an object that exhibits certain aesthetic properties or qualitieswith love and beauty being paramount onesand the medium by which the ineffable consciousness is made manifest is through the use of tropical language (figures of speech), in the enunciation. Ultimately, I argue that mystics are bound to articulate the experience of divinity, since it connotes a recognition of that presence of God which is realized in the imaginary; and thus, their protestations about ineffability are problematic.

The Assessment and Treatment of Disordered Speech and Voice in Parkinson’s Disease Using a PC-based Telerehabilitation System

Gabriella Amalia Constantinescu — 2010-11-09T00:00:00Z

Individuals with Parkinson’s disease (PD) face numerous access barriers to speech-language pathology services including their own physical incapacity, difficulties with transport, travel, cost of travel and the large distances to healthcare facilities. Telerehabilitation is a possible solution for these problems, whereby rehabilitation services may be delivered remotely to patients via telecommunication and information technologies. A number of studies have demonstrated the feasibility of telerehabilitation via personal computer (PC) based systems for assessment and treatment of dysarthria, apraxia of speech, aphasia and voice disorders in adults with neurological impairments. To date, however, no large-scale studies have specifically focused on the online assessment and treatment of the speech and voice disorder associated with PD. The aim of this thesis was to investigate the validity of telerehabilitation for the assessment and treatment of PD and to provide a framework for telerehabilitation use in this area. For the studies in this thesis, a custom made PC-based telerehabilitation system was developed. The system incorporated a number of features to meet face-to-face requirements for the management of PD including: (1) real-time videoconferencing which operated on a 128 kbit/s Internet connection; (2) control of the participant web cameras remotely; (3) store-and-forward function; (4) the ability to display printed materials for the participant remotely; (5) ease of operation; and (6) the ability to objectively measure real-time calibrated average recordings of vocal sound pressure level (SPL), fundamental frequency (F0) and duration. The initial component of the research established the validity of the telerehabilitation system as an acoustic measurement tool via a series of calibration and verification phases, where comparisons were made to standard face-to-face reference measurement tools (Chapter 2). The studies confirmed the accuracy of the telerehabilitation system with non-significant differences in acoustic measures obtained between the telerehabilitation system and reference tools. All measures also fell within predetermined clinical criteria. Following this, a series of four studies were conducted to achieve the aim of this thesis. The first cohort study aimed to investigate the validity and reliability of online assessment of the speech and voice disorder associated with PD (Chapter 3). A total of 61 participants with PD and mild to severe hypokinetic dysarthria took part in the laboratory-based equivalence study. The participants were assessed simultaneously in the online and face-to-face environments. The assessment protocol included perceptual measures of voice and oromotor function, articulatory precision, speech intelligibility, and acoustic measures of mean SPL, maximum F0 range and maximum duration of sustained vowel phonation. The level of agreement between the online and face-to-face ratings was determined using several different analyses, depending on the parameter. These included percent close agreement, quadratic weighted Kappa and the Bland and Altman limits of agreement. The results revealed that for all perceptual parameters, percent close agreement between the two environments was within the predetermined clinical criterion of 80%. However, a number of these parameters fell below the clinical criterion of good agreement based on the quadratic weighted Kappa. The discrepancy in findings was considered to relate to rater variability commonly seen in perceptual ratings and/or the nature of the statistic per se, rather than the online environment. For the remaining speech intelligibility and acoustic parameters, the Bland and Altman limits of agreement analysis revealed comparability between the two environments, with only the word intelligibility values falling below the clinical criterion. It was suggested that speaker severity may have influenced the results on this parameter. The intra- and inter-rater reliability scores were also comparable between the online and face-to-face environments, achieving moderate to very good agreement for all tasks. Subsequent to the validation of the online assessment of hypokinetic dysarthria, three treatment studies were conducted. The first was a laboratory-based randomised controlled non-inferiority trial investigating the validity of online treatment delivery for the speech and voice disorder associated with PD. In this study, 34 participants with idiopathic PD (IPD) and mild to moderate hypokinetic dysarthria received the Lee Silverman Voice Treatment (LSVT®) for PD, in either the online or face-to-face environment (n = 17 in each). The study findings were very promising, with non-inferiority of the online LSVT® modality confirmed for the primary outcome measure of mean change in SPL on a monologue task. Non-significant main effects of treatment environment, dysarthria severity and interaction effects were also noted across all of the acoustic and perceptual parameters (p > .05). Further, it was encouraging to note that significant gains following the LSVT® were made on the majority of acoustic and perceptual parameters for participants in both treatment environments (p < .05 for SPL tasks; maximum F0 range; all voice parameters and speech intelligibility). In order to determine the feasibility of online LSVT® for complex cases of PD, the second laboratory-based treatment study was conducted. Four participants with marked communication, cognitive and physical difficulties took part in the study. The participants had been diagnosed with either IPD and had undergone neurosurgical intervention or with progressive supranuclear palsy. Online treatment delivery for these complex cases showed promise, with functional improvements in communication reported for all cases. Although the treatment gains on the perceptual and acoustic measures were generally variable, it was evident that the outcomes were influenced by the complex participant factors that were all external to the treatment environment. In the final study, a single participant with IPD and mild hypokinetic dysarthria received the LSVT® remotely from his home, in order to determine the feasibly of home telecare for PD. Substantial improvements were achieved on the majority of acoustic parameters (SPL tasks and maximum duration of sustained vowel phonation), and on the perceptual measure of vocal breathiness. The results of the study demonstrated the feasibility of home-based treatment for PD in the real-world setting, within an individual’s most natural and preferred environment. Overall, the findings presented in this thesis provide evidence for the validity of assessing and treating the disordered speech and voice of PD via telerehabilitation. Although some challenges unique to the online environment were encountered in the studies and were mainly due to the audio and video quality during videoconferencing, the participants and speech-language pathologists (SLPs) were able to appropriately manage these without substantial impact on the online delivery overall. The high participant satisfaction with the online modality across all studies further supported this, where the majority of participants (80% and above) were more than satisfied or very satisfied with the online modality overall. The thesis provides a framework for the delivery of telerehabilitation services for people with PD, with the potential to alleviate the current access issues that exist for this population. Further research is needed to build on the findings in this thesis and should include the validity of home-based assessment and treatment, in-depth investigations of participant and SLP satisfaction and cost-benefit analyses of telerehabilitation for PD. Such investigations are necessary in order to determine the complete benefits of telerehabilitation as an additional or alternate mode of service delivery for this population, and the circumstances in which this approach is most suitable.

The association between endophytic N2-fixing bacteria and Australian sugar cane

Robertson, Suzanne K. — 2008-11-21T00:00:00Z

The association between micronutrients status, stunting, body mass index and adiposity among Mexican American children

Gunanti, Inong Retno — 2012-12-13T19:49:04Z

The association between rumen microbial protein production with rumen microbial community structure.

Karen Harper — 2012-03-22T00:00:00Z

Abstract Beef production in tropical northern Australia is generally limited by poor feed quality during the critical dry season. The digestibility of this poor quality feed is directly related to rumen microbial activity and community composition, and despite this important relationship, a review of available literature highlighted our limited understanding of this. Supplementation with nitrogen (N) is a practical strategy to improve the liveweight (LW) gain of cattle grazing low quality pastures, however, the effect of various forms of N supplementation on the composition of the rumen microbes is unknown. N supplementation will increase microbial crude protein (MCP) production but the efficiency of MCP production (EMCP) is difficult to increase. Supplementation with spirulina algae increased EMCP and therefore provided a working model to compare the rumen function and community structure of steers with low and high EMCP values when fed tropical pastures. This study was initiated to develop a better understanding of rumen ecology the factors that govern microbial community structure and growth to increase the EMCP and associated animal performance in tropical production systems. The aims of this study were firstly to identify the changes in microbial species of the rumen when various forms of N were supplemented, and secondly to examine the relationship between the microbial community structure, EMCP and LW gain, as it relates to tropical pastures and supplement type. Experiment 1 investigated the use of the N supplements, urea and spirulina algae, to enhance the EMCP of steers fed a basal diet of Mitchell Grass (Astrebla spp.). Data from a parallel study on rumen function showed a significant improvement in the EMCP with spirulina algae supplementation. In this experiment denaturing gradient gel electrophoresis (DGGE) was applied to compare the effects of treatments on rumen bacterial community structure. Phylogenetic sequence analysis was performed on cloned DGGE bands which represented bacterial species common across all treatments (core bacteria) and supplement specific bacteria. Experiment 2 investigated the effect of N supplements (urea, spirulina algae and cottonseed meal (CSM)) on LW gain of steers fed a basal diet of Speargrass (Heteropogon contortus). LW data from a parallel component of the experiment demonstrated significant LW gains under N supplementation. The 454 pyrosequencing technique was applied providing a comprehensive examination of microbial diversity, community structure, and identification of the core bacteria and bacteria specific to supplement treatments. The core bacteria, which were represented as common bands across all treatments, were identified in Experiment 1. The 454 pyrosequencing (Experiment 2) identified and validated a stable core group of bacterial operational taxonomic units (OTUs) present in all steers. The core group of bacteria could not be characterized to a species level because there are no cultured representatives in the available databases. Supplement specific bacteria were identified in Experiment 1 and 2 using the different molecular techniques however bacterial species again could not be characterized. In both experiments there was animal to animal variation in microbial community structure that was not fully attributable to N supplement treatments. Each steer appeared to have its own unique bacterial profile. In Experiment 1, due to the incomplete Latin square design, it was shown that the profile for each animal was stable when changes in supplement were imposed across the three runs. In Experiment 2, there was considerable animal to animal variation in microbes at both the phyla and the genera level. Across both experiments, a greater bacterial diversity was found in rumen samples from animals fed diets supplemented with the medium (130-170 gRDP/kg DOM in Experiment 1 and 0.14-0.16 g N/kgLW/day in Experiment 2) levels of protein supplement. The bacterial diversity did not correlate with EMCP values in Experiment 1, however, it is likely that any effects were confounded since with high spirulina algae supplementation, rumen retention time was significantly reduced, which is likely to affect microbial populations. In Experiment 2 the higher bacterial diversity was strongly associated with greater LW gains. In an attempt to provide a better understanding of the diversity changes, rumen bacteria community profiles were compared in both experiments. Comparing DGGE profiles in Experiment 1, there were significant changes only at the high and low planes of N with high and low EMCP steers clustering separately, suggesting a relationship between bacterial community profile and EMCP at the extremities of the N supplementation range. The use of 454 pyrosequencing in Experiment 2 provided more clarity of the changes in the OTUs with supplementation by means of OTU networks. These networks showed two distinct clusters that related to urea and protein supplementation treatments, however many OTUs were common across all treatments. It may be concluded that supplementation of protein increases the diversity of rumen bacteria as well as improves the growth conditions for the entire bacterial community, therefore providing more nutrients to the host animal leading to improved EMCP and increased LW gains.

The association between shift work, body mass index and low back pain in a cohort of nurses and midwives.

Isabella Zhao — 2012-03-20T00:00:00Z

Background Shift work is a defining occupational feature of nursing and midwifery professions. It has various adverse effects that could ultimately affect building and maintaining a healthy nursing and midwifery workforce. Firstly, shift work interrupts people‟s daily routines; therefore, it may lead to poorer lifestyle factors that increase one‟s risk of being overweight or obese. Secondly, shift work is reported to be one of the occupational risk factors for low back pain, which is a common problem among nurses. Aim This research aims to examine the association between shift work, body mass index(BMI) and low back pain (LBP) among nurses and midwives recruited from Australia, New Zealand and the United Kingdom. Methods To understand the impact of shift work on BMI, both cross-sectional and longitudinal cohort studies were undertaken using data from the Nurses and Midwives‟ e-cohort Study (NMes). The NMeS is a longitudinal population-based study recruiting nurses and midwives from Australia, New Zealand and the United Kingdom; and it is conducted completely electronically from recruitment to follow-up. There were 10, 120 total registrants, of whom, 7604 registrants completed survey 1 and 5280 registrants completed survey 2. The average follow-up period was two years. Two cross-sectional studies were carried out to explore the effects of shift work in general and specific shift types (rotating shift work and night-only shift work) on BMI. A longitudinal cohort study was undertaken to better understand the causal relationship between shift work and BMI. Similarly, a second longitudinal study was conducted to investigate the association between shift work and LBP, which also included an interaction analysis of the combining effects of shift work and overweight/obesity on LBP. Detailed statistical methods used for each study were discussed in each paper. Results The results from the two cross-sectional studies showed that almost 60% of the recruited nurses and midwives were overweight or obese. Shift workers were at higher risk of being overweight and obese compared to day workers (aRR: 1.15, 95% CI 1.03 - 1.28, p = 0.013; aRR: 1.14, 95% CI 1.02 - 1.30, p = 0.02, respectively). Regarding the specific shift types, rotating shift work was found to be associated with both overweight and obesity (aRR: 1.02, 95% CI 1.004 – 1.03 p = 0.007; aRR: 1.02,95% CI 1.004 – 1.04, p = 0.02, respectively); and night-only shift work was only found to be associated with obesity (aRR: 1.02, 95% CI 1.002 – 1.04, p = 0.031), but not associated with being overweight. The adjusted relative risk (1.02) was small, which may not reflect clinical significance although the results were statistically significance. Furthermore, shift work is consisted of many different kinds of schedules including rotating shift and night-only shift. Therefore, it was decided to further test the association between shift work in general (including any kind of shift schedules) and BMI using a longitudinal study design, which found a decrease in BMI among those participants who maintained day work and especially among those who changed from shift work at Survey One (S1) to day work at Survey Two (S2)(decrease in BMI of 3.02) during the two years‟ follow up; an increase in BMI among those participants who maintained shift work and those who changed from day work at S1 to shift work at S2 (p < 0.001). These studies demonstrate that shift work is significantly associated with overweight/obesity/increase in BMI; and overweight or obesity is reported to have an impact on LBP. Therefore, in the longitudinal study of examining the association between shift work and LBP, the impact of the interaction between shift work and overweight/obesity on LBP was also examined. The results showed that shift workers were at higher risks of developing LBP compared to day workers (aOR: 1.15, 95% CI 1.05 – 1.40, p = 0.03). The [shift schedule * BMI classification] interaction showed that shift workers who were overweight and obese were more likely to develop LBP than day workers (overweight: aOR: 1.23, p < 0.01; obesity: aOR: 1.34, p < 0.01). Conclusion Shift workers were at higher risk of being overweight or obese and developing LBP compared to day workers. Whilst shift work cannot be avoided in nurses and midwives, interventions targeting weight reduction and LBP prevention should be tailored to the specific work settings. If the adverse effects of shift work can be mitigated with strategic intervention, the potential workforce implications of these morbidities may be prevented.

Theatre Audience Contribution through the Post-performance Discussion

Caroline Heim — 2009-12-01T00:00:00Z

This dissertation addresses a significant gap in audience-orientated criticism by introducing a new approach to theatre audience research: audience contribution through the vehicle of a postperformance discussion. Audience contribution considers the physical and vocal behaviour of audience members as contributions to the theatrical event. Much scholarship has concentrated on the written and performance texts. What I posit as the audience text, comprised of audience contributions, has been predominantly ignored. The audience text is an integral part of the theatrical event that changes, adds to and informs the theatrical experience for audience and arts professionals alike. Over the past century the audience role has changed from interactive contributor to passive receiver. For the contemporary theatre audience member, opportunities to contribute to the theatrical event have been limited to laughter, applause and consumerist practices such as the purchasing of theatrical merchandise. Similarly in much theatre audience theory, audiences are perceived as passive receivers of the drama whose only active contribution is through autonomous cognitive meaning-making processes. The study takes into account the extant audience theory of audience reception and builds on this. Post-performance discussions, which have risen significantly in popularity in the last decade, are an under-explored and under-utilised avenue for audience contribution. A new method for the facilitation of post-performance discussions that encourages audience contribution and privileges the audience voice is introduced. Case studies of post-performance discussions held after performances of Anne of the Thousand Days and Who’s Afraid of Virginia Woolf? trial this new discussion model. An audience text is created that informs the theatrical event and a new role for the contemporary audience is discovered: audience critic. Through the post-performance discussions, audience members become active contributors to, and co-creators of, the theatrical event. Audience contribution has significant implications for audience theory and theatre practice alike.

The attainment of marketing specification for open pit mined direct-shipping low value commodities through planning and blending

Mol, Omer — 2012-12-05T14:58:31Z

The attenuation of chronic complications in experimental diabetes by l-arginine

Ong, Leslie Gin Teck — 2011-12-20T00:00:00Z

The Australian rugose corals : their morphological characters, their systematic classification, and their use in a reinterpretation of the Australian stratigraphic record

Hill, Dorothy — 2012-10-30T12:26:02Z

The Australian South-east Fishery: An analysis of quota species supply and demand

Bose, Shekar. — 2007-08-24T17:46:41Z

The bacterial community in the foregut of the dromedary camel

Anjas Samsudin — 2011-10-18T00:00:00Z

Samsudin, A. A. 2011. The bacterial community in the foregut of the dromedary camel. PhD. thesis, The University of Queensland, Australia. The digestive systems of the Arabian camels are anatomically different from that of the true ruminants such as cattle and sheep. The forestomach of camelids consists of three chambers, whilst in the true ruminant, they have four. Despite having differences in anatomical structures, functionally they are the same. The molecular diversity of the foregut bacterial community in the dromedary camel (Camelus dromedarius) in Central Australia was investigated through comparative analyses of 16S rRNA gene sequences prepared from the foregut contents of 12 adult feral camels fed on native vegetation. A total of 267 near complete 16S rRNA clones were examined, with 151 operational taxonomic units (OTUs) identified at a 99% species-level identity cut-off criterion. The prediction of actual diversity in the foregut of the dromedary camel, using the Chaol’s approach, was 238 OTUs, while the richness and evenness of the diversity estimated, using the Shannon’s index, was 4.84. The majority of clone bacteria in the current study was affiliated with the bacterial phylum Firmicutes (67% of total clones) and was related to the classes Clostridia, Bacilli, and Mollicutes, and these were followed in number by the Bacteroidetes (25%) that were mostly represented by the family Prevotellaceae. The remaining phyla consisted of Actinobacteria, Chloroflexi, Cynophyta, Lentisphaerae, Planctomycetes, Proteobacteria, and Sphirochaetes. Moreover, 11 clones of cultivated bacteria were identified as Brevundimonas sp., Butyrivibrio fibrisolvens, Prevotella sp., and Ruminococcus flavefaciens. The novelty in this foregut environment is remarkable where 97% of the OTUs were distantly related to any known sequence in the public database. In the second study, numerous genera of cellulolytic bacteria, involved in fibre degradation in the rumen, and their functional role in the foregut of the dromedary camels (Camelus dromedarius) were investigated using 16S rRNA gene libraries. The foregut content from five adult feral camels, fed on native vegetation, was inoculated in three different fibre enrichment media, namely; cotton thread (CT), filter paper (FP), neutral detergent fibre (NDF). A total of 283 near complete 16S rRNA clones were examined, with 33 OTUs identified at a 99% species-level identity cut-off criterion. The actual diversity was estimated using Chaol’s approach, with 42 OTUs predicted, while the richness of the diversity estimated using Shannon’s index was 2.82. LIBSHUFF analysis of the three 16S rRNA clone libraries revealed significant differences across all of them. Clostridium bifermentans were found in all three libraries, while Eubacterium sp, Pseudobutyrivibrio ruminis, Pyramidobacter piscolens and Schwartzia succinivorans were found in both CT and FP enrichment media only. The current results in the present study showed significant findings of fibre-degrading bacteria that inhabit the foregut of wild dromedary camels. In the third study, the total bacterial community, F. succinogenes and R. flavefaciens, in the foregut of the dromedary camel was measured by quantifying the cell number of each respective species using real-time PCR. The samples from this study were obtained from the same samples used in the second study. The standard curve gave a linear relationship (R2=0.969) with the equation y= -2.975x+42.33. Using an absolute quantification method, the numbers of cells in one millilitre of each sample ranged from 4.07x106 to 2.73x109 for total bacteria, 1.34x103 to 2.17x105 for F. succinogenes and 5.78x101 to 3.53x104 for R. flavefaciens. The mean cell number for three set of primers used in the current study demonstrated that the number of general bacteria prevalent in the CT enrichment media was 242-fold higher than in rumen content. The mean cell number of F. succinogenes was highest in the FP enrichment media at approximately 107-fold, whereas for the R. flavefaciens targeted primer, the NDF enrichment media had the highest mean cell number with approximately 4-fold when compared to the rumen content. Despite having a low population density in the rumen samples compared to samples from domesticated ruminants, the data presented here would help farmers to develop feeding regimes for dromedary camels since they do not share an interest in the forage consumed by domesticated livestock, especially during a drought season. The final study of this thesis was to identify the unrealized fibre-degrading bacteria in this environment niche using a combination of culturation and molecular methods. Samples in this study were obtained from the same enrichment media (CT, FP and NDF) used in the second and third studies. In this study, only 66 partial-length (700bp) sequenced isolates were successfully recovered. The majority of the isolates in this study were represented by the phylum Firmicutes followed by Proteobacteria and Actinobacteria. The phylum Firmicutes was dominant in the CT and FP enrichment media, while a reasonable number of Proteobacteria was present in the NDF enrichment culture. The genus Clostridium was found in all enrichment media and was the most dominant genus with the highest frequency, 56.1% of isolates, followed by Escherichia coli (19.3%), Actinomyces ruminicola (15.8%) and Streptococcus lutetiensis (8.8%). The results of the culture dependent methods revealed the difficulties in culturing fibre degrading bacteria and more work is needed to address this. None of the isolates obtained from the fibre-enriched media was able to degrade cellulose independently, confirming the complexity of the microbial ecosystem and the importance of the interaction between bacterial groups to degrade fibre. Overall, results of this study provided an insight into a microbial system of a herbivore that has not been thoroughly investigated. Furthermore, the study of the fibre-degrading bacterial community in the foregut of the dromedary camel has provided data that, hopefully, will contribute to the sustainable farming of camels well into the future. These animals do not compete with domesticated ruminants such as cattle and sheep either in feeding behaviour or in the type of feed these animals consume, so the data could support plans for the commercial management of a potential new livestock industry in Australia.

The bassoon at the time of Carl Maria von Weber

Gould, Alannah. — 2007-08-24T00:00:00Z

The behavioural biology and management of southern hairy-nosed wombats (Lasiorhinus latifrons) in captivity

Descovich, Kristin — 2012-11-19T10:22:48Z

The behavioural responses of children with cerebral palsy to tactile stimuli

Clayton, Kellie. — 2012-02-21T00:00:00Z

The behaviour and effects of radiation-induced gas in irradiated aluminium-lithium alloys.

Smith, Ian Oswald. — 2010-09-03T00:00:00Z

The behaviour and physiology of the gravid flatback turtle (Natator depressus)

Sperling, Jannie Bech — 2008-11-21T00:00:00Z

The study describes for the first time the detailed behaviour of flatback sea turtles (Natator depressus) between nesting events within the same season. It includes both horizontal and vertical movements, obtained through satellite telemetry and with Time-Depth-Recorders, respectively. Two genetically and geographically distinct populations were studied; Curtis Island, Queensland and Bare Sand Island, Northern Territory. While the flatbacks at Bare Sand Island appeared to spread randomly out from the island, the flatbacks at Curtis Island made use of the protected waters of the Gladstone port and harbour area. The flatbacks vertical movements were compared to that of loggerhead turtles (Caretta caretta) nesting at Mon Repos Conservation Park, Queensland. Both species spent <10% of their time at or near the surface and displayed dive types that could be referenced to terminology developed for sea turtle species. Most prevalent were dive types 1, 3 and 4, where the first is thought to represent dives during which turtles are inactive on the seabed. In the latter two turtles are thought to slowly ascend in mid-water, as a result of a slow increase in buoyancy, while swimming some distance horizontally. Dive type 1 was by far the most common dive type in the flatback turtle, while dive type 3 was equally as important as type 1 in the loggerhead. Dive type 1 was in both species more common in the middle third of the period, when eggs are maturing. There was some evidence of a diel pattern, with dive type 1 more common during the day in flatbacks and during the night in loggerheads. An important finding was that flatback turtles show long dives, up to 98 min. The mean duration of 50 min for dive type 1 is about twice as long as commonly seen in loggerheads and other large sea turtles, while comparable to the smaller olive ridley (Lepidochelys olivacea) and hawksbill turtle (Eretmochelys imbricata). Part of the explanation for long dives appears to include an oxygen carrying capacity at the high end of the range for diving reptiles and higher blood oxygen saturation at comparable partial pressures of oxygen. Internesting intervals were correlated negatively with sea temperature in both flatback and loggerhead turtles, but could not be described by a single correlation. The results showed that the modal temperature calculated for the egg maturation part of the interval, i.e. approximately the first nine days, depicts the temperature important to pre-ovipositional egg development better than mean temperature measured over the whole internesting interval.

The behaviour and reproductive biology of captive southern hairy-nosed wombats (Lasiorhinus latifrons)

Lindsay Hogan — 2010-08-14T00:00:00Z

Information on the reproductive biology and behavioural ecology of southern hairy-nosed wombats (Lasiorhinus latifrons) is limited. Field reproductive and behavioural studies have been hindered by the difficulties associated with the routine recapturing and direct observation of wombats in the wild. Additionally, due to their extremely poor breeding success within captivity and the intrinsic complications associated with the monitoring of nocturnal and semi-fossorial activity, little formal research has been conducted on captive-held individuals. The overarching objectives of this research were to gain a better understanding of (1) both male and female L. latifrons reproductive physiology/behaviour that will lead to improved captive breeding program outcomes and (2) captive L. latifrons activity rhythms and behavioural time budgets in order to identify the impacts of captivity on wombat behaviour and wellbeing. The primary experiments of this research were centred around the development of ‘non-invasive methodologies’ for the collection of biological samples (Chapter 2), direct observation of behaviour and activity (Chapter 3), assessment of male reproductive function (Chapter 4), detection of female oestrus and cyclicity (Chapter 5), characterisation of activity patterns (Chapter 6) and monitoring of stress (Chapter 7). The last two experiments also tested the efficacy of gentling (Chapter 7) and enrichment (Chapter 8) to improve the wellbeing of the captive wombats. Faecal steroid analysis is a non-invasive tool that allows the stress-free monitoring of steroid hormones and has been used on a wide range of animal species to examine their reproductive physiology and adrenal function. The usefulness of faecal hormone analysis, however, is directly related to the reliable collection and identification of individual faecal samples. In group-housed animals, the identification of faecal samples can be difficult and time consuming and is generally only accurate if a marker is incorporated into the animal’s diets. Hence, Chapter 2 examined the usefulness of non-toxic plastic glitter as a faecal marker in group-housed L. latifrons. Forty-two food treats were tested as vehicles for the oral delivery of glitter; of these, vehicle palatability (> 75% consumed) and consistency of intake (eaten > 80% of times offered) was high for six treats: (1) golden syrup with horse pellets, (2) golden syrup with weetbix, (3) pitted-dates, (4) honey with kangaroo pellets, (5) nutrigel with rolled-oats and (6) strawberry sauce with rolled-oats. Marker mean rate of passage was 2.9 ± 0.5 d, with maximal output occurring 4.2 ± 0.3 d after oral administration. A minimum marker dose of 1.6 g was necessary to achieve high labelling consistency (> 2 flecks of glitter were defaecated in > 90% of pellets) and this dosage was required every 3 days to maintain a steady and detectable state of marker output. Twelve glitter colours were tested and optimum labelling results were obtained with gold, metallic red, metallic green and metallic blue. Once established, this technique was then used to facilitate the long-term collection of faecal samples in order to characterize patterns of reproduction (Chapter 4), monitor ovarian events (Chapter 5) and to quantify stress-responses (Chapter 7) via faecal steroid analysis. The direct observation of wombats is difficult; individuals are not easily identified and the animals are often out-of-view (residing in burrows) or obscured (low-light conditions) during sampling. Published behavioural data available on L. latifrons is largely restricted to visual observations made during dawn and dusk only, whilst published activity data pertains to time spent in or out of the burrows rather than actual physical activity. Hence, Chapter 3 tested the effectiveness of two electronic monitoring systems to remotely observe wombat behaviour and physical activity. Digital video-surveillance proved to be an effective technique for the recording and monitoring of captive wombat behaviour. Animal visibility was good, behavioural events unambiguous and the system enabled the long-term, concurrent recording of behaviour with no direct human presence. Similarly, radio-telemetry proved to be an effective way of recording captive wombat physical activity. The system was reliable, removed observer error and enabled the continuous and concurrent recording of wombat activity. Once established, these two remote monitoring systems were then used to describe wombat behaviour elements and activity patterns (Chapters 3 and 6). After a year of continuous monitoring it was established that the wombats spent, on average, 69.9% sleeping, 8.8% lying resting, 5.2% feeding, 5.2% exploring, 4.3% stereotyping, 2.5% sitting-at-rest, 1.7% digging, 1.4% foraging, 0.4% being handled, 0.3% sun-basking, 0.2% grooming and 0.1% courtship/mating. Temporal patterns were bimodal for 8/12 of the wombat behaviours and unimodal for the remaining four. The mean proportion of total daily time spent active was 18.2 ± 1.8%. Daily activity patterns were characterized by a strong circadian cycle, with high nocturnal activity and low diurnal activity. Daily onset (18:19 h) and cessation (04:34 h) of activity was seasonally constant and strongly associated (P < 0.01) with sunrise/set, but not influenced by either temperature or humidity (P ≥ 0.09). At night there was an alternating rhythm of active and rest periods, with activity peaking at the beginning (19:00 h) and end (03:00 h) of each night. Activity was seasonal with annual changes in temperature, humidity and night-time length being the triggers of variation. Mean daily activity was greater during winter (19.7%) and spring (18.9%), than during summer (16.3%) and autumn (17.2%), with the degree of activity being largely governed by ambient temperature. Feeding, sleeping and stereotyping varied significantly with season. Feeding and stereotyping were negatively associated with ambient temperature and humidity, whilst being positively associated with night-time length; the inverse relationship was true for sleeping. Ambient temperature exerted its largest effect on time spent feeding; feeding times decreased by 3.1 min / 1ºC above 13ºC and compared to spring, feeding times were reduced by 41% during summer. There is, at present, very little data published on male and female wombat reproduction. The reticence of wombats to breed in captivity makes it difficult to study reproduction in captive animals and their cautious, nocturnal nature makes field studies challenging. Non-invasive techniques to monitor reproductive status/function will assist in improving the general knowledge of wombat reproduction and the development of new captive breeding management strategies, by allowing the easy monitoring of captive animals. Thus, the series of experiments in Chapters 4 and 5 explored the efficacy of a number of non-invasive methodologies to assess male reproductive function, monitor female cyclicity and predict the timing of oestrus. To address the pulsatile nature of testosterone, a GnRH agonist stimulation test was developed in the male. IM injection of 4 μg of buserelin (a GnRH agonist) resulted in an increase (P < 0.05) in plasma testosterone concentrations, with maximum secretion occurring at 90 min. Thereafter, plasma testosterone concentrations remained near maximum for 150 min. There was a strong, positive correlation (r = 0.73, P < 0.01), between pre-stimulation testosterone concentrations and the maximal concentrations achieved post-stimulation with post-stimulation concentrations varying between individuals (P < 0.01). These findings indicate that individual male wombats can show large fluctuations in plasma testosterone concentrations over time and that a GnRH agonist can be used to obtain a diagnostic index of the prevailing testosterone biosynthetic capacity of the testes. This technique was then used as part of a larger experiment (Chapter 4) to investigate seasonal changes in male wombat reproduction. To date, the effects of breeding season on captive male wombat fertility have yet to be examined and a better understanding of this phenomenon will pinpoint the most favourable times for mating. Seasonal changes in a series of male reproductive parameters were non-invasively examined over a 18 month period: (1) testosterone concentration, both plasmic and faecal, was monitored using enzyme-immunoassays (EIA), (2) testicular volume was measured manually using digital vernier callipers, (3) sperm production was evaluated by way of spermatorrhoea, whilst (4) prostate and bulbourethral gland cross-sectional areas were assessed by ultrasonography. Plasma testosterone secretion increased in early-winter, peaked late-winter and declined in early-spring (P < 0.01). No seasonal variation (P = 0.22) in faecal testosterone metabolite concentrations was apparent. Testicular volume showed no significant variation (P = 0.29) over the sampling period and spermatozoa were found in the urine throughout the year; these two observations suggest that the captive male wombats remain spermatogenically active year round. While there was no significant seasonal change (P = 0.20) in prostate size, bulbourethral gland size increased in late-autumn, peaked in mid-winter and declined in early-summer (P < 0.01). Ultimately, captive male reproductive function was influenced by seasonality, with a peak in plasma testosterone and bulbourethral gland size occurring in winter (Jun-Aug). In an attempt to characterize oestrus-specific behaviour and develop a reliable method of oestrus detection in L. latifrons, the reproductive physiology and behaviour of eight adult females was monitored for a period of 12 months (Chapter 5). The reproductive behaviour of both sexes (4♂: 8♀) was monitored using 24-h video surveillance, whilst female physical activity was remotely measured using radio-telemetry. A faecal sample was collected every three days, from each female to assess changes in faecal progesterone and oestradiol-17β metabolite concentrations. Each female also received an injection of 0.01, 0.1 or 0.2 mg/kg of oestradiol benzoate (OB) in one of two hormone trials. Video surveillance revealed that the courtship (n = 426) and mating (n = 46) ritual of L. latifrons consisted of 13 distinctive behaviours expressed over six obvious phases: investigation, attraction, chase, restraint, copulation and recovery. Reproductive behaviour was observed in five (2♂, 3♀) wombats, with female receptivity occurring at night and lasting for only 13-h. Faecal progesterone metabolite analysis proved to be a reliable method for mapping oestrous cycle activity, but was not useful for the prediction of oestrus. Six out of the eight female wombats displayed periods of elevated progesterone secretion. From these six individuals, 23 luteal phases, 12 follicular phases and 12 oestrous cycles were recorded, with a mean (± SE) length of 20.9 ± 1.1 d, 11.6 ± 0.6 d and 31.8 ± 1.1 d, respectively. In contrast, changes in the secretion of faecal oestradiol-17β metabolites provided little instructive information on oestrous cycle activity and were not associated with oestrus. Administration of OB resulted in a spike of oestradiol-17β metabolites in the faeces 3-4 d later, but was not dose dependent nor did it elicit oestrus-behaviour. Activity monitoring does not appear to be a useful method for detecting oestrus in L. latifrons, as changes were not associated with key events in the oestrous cycle. However, 24-h video surveillance proved to be a reliable method for oestrus detection in the captive L. latifrons. Threatening or aversive stimulation is experienced in wild and captive conditions alike and evokes similar physiological responses. If an animal, wild or captive, cannot cope with this stimulation it may experience stress. An uncontrollable source of stress for all captive animals lies in their interactions with their human caretakers. A high or persistent fear of people can be a source of psychological stress for animals in captivity. Positive handling is a potent method of reducing the specific fear of human beings through desensitisation. The response of animals to handling by humans has been extensively evaluated in domesticated species, but rarely assessed in wild animals. Hence, Chapter 7 examined the usefulness of a regular handling program to lower the behavioural fear and physiological stress responses of L. latifrons to human interaction. Adult L. latifrons (n = 12) were exposed to two different treatments in a replicated design: (1) daily handling: 15 min of tactile contact from a human handling 5 d/wk for 12 wk and (2) no-handling: no contact apart from that received during routine husbandry. The effect of handling was assessed using overt response, human approach, stressor and novel stimulus tests. Synthetic ACTH was used to validate a method for monitoring faecal cortisol in L. latifrons by EIA. IM injection of 250 μg of Synacthen resulted in a significant (P < 0.05) increase in plasma and faecal cortisol concentration 30 min and 2 d after administration, respectively. Handling positively affected the behavioural responses of the wombats to human approach and contact in two ways: (1) a significant reduction (P < 0.01) in the wombat’s mean flight distances to human approach and (2) a significant (P < 0.01) decline in the strength of the wombat’s behaviour-based fear reactions (i.e. fear scores) to human proximity and contact. Handling had no discernable effect on the wombat’s physiological stress responses to human contact or on their reactions to novelty. While faecal cortisol secretion increased in response to a stressor test involving human contact, it was not alleviated by regular handling (P = 0.84). Similarly, the wombat’s reactions to unfamiliar objects during novel stimulus testing were also unaffected (P = 0.17) by the handling treatment. Therefore, handling exerted its main effect on the behavioural responses of the wombats, representing fear responses to human handlers, rather than reducing their anxiety. The main difference between wild and captive environments lies in the differential ability of control, i.e. a free-living animal is able to control its amount of incoming stimulation whereas a captive animal has a limited capacity to alter the external stimulation to which it is exposed. Without natural behaviour outlets, captive animals have to rely on abnormal behaviour patterns to modify their expectations of the captive environment and exert some control over incoming stimulation. A ‘stereotypy’, defined as a repetitive movement pattern with no apparent goal or function, is a common abnormal behavioural pattern expressed by zoo animals. Stereotypies are of concern because of their association with poor welfare. A previous behavioural study revealed that common wombats (Vombatus ursinus) in captivity are very susceptible to the development of stereotypic behaviour. For that reason, the final experiment (Chapter 8) was designed to further examine stereotypic behaviour in wombats and tested whether environmental enrichment could be used to reduce its prevalence. Adult L. latifrons (n = 12) were subjected to two different treatments in a replicated design with 12 week periods: (1) Enrichment – animals received feed and olfactory enrichment, 5 d/wk and (2) No-enrichment - animals received the standard captive diet only. Wombat behaviour was remotely observed via 24-h video surveillance. Eight out of the 12 wombats displayed one of four stereotyped movements (straight-line pacing, boundary pacing, figure-8 pacing or wall-climbing), with time spent stereotyping ranging from 61-129 min/d (mean 87 ± 7 min/d); time devoted to stereotyping took up 4-9% of the daily budget. There was a significant increase in foraging (333%) and exploration (13%) in response to enrichment. Enrichment also encouraged the expression of a wider range of naturalistic foraging behaviours. Despite these positive effects, enrichment had no discernable effect on the time spent stereotyping (P = 0.87) or inactive (P = 0.13). Despite the fact that stereotypies and inactivity were not reduced by enrichment, animal welfare was still enhanced as there was a notable improvement in natural wombat-specific behavioural expression and diversity.

The behaviour of inert gas produced in irradiated alloys.

Hastings, Ian James. — 2010-08-25T00:00:00Z

The Behaviour of the Lumbar Paraspinal Muscles in People with Recurrent Low Back Pain During Symptom Remission

David MacDonald — 2011-07-06T00:00:00Z

Low back pain is a prevalent and costly musculoskeletal condition. It has been estimated that between 60 and 90% of people will experience an episode of low back pain in their lifetime. At the moment three million Australian adults are suffering with low back pain and one million of those people will continue to have recurrent episodes. Changes in the behaviour of the trunk muscles have been argued to contribute to these recurrent episodes and rehabilitation strategies have been developed to optimise, enhance or restore the function of those muscles in this population. Some rehabilitation strategies targeting the paraspinal muscles have focused on the lumbar multifidus based on biomechanical models that argue the lumbar multifidus can contribute to the control of motion at the lumbar spine and limited electromyographic and imaging data that suggest that the morphology and behaviour of the lumbar multifidus are altered in people with low back pain. Based on morphological data, it is believed that changes in multifidus behaviour are specific to the components of the multifidus that cross only two lumbar segments. However, specific recording of the deep and superficial fibres of the lumbar multifidus had not been undertaken to test this belief. Furthermore, determining whether changes in the behaviour of the lumbar multifidus are present in people with recurrent low back pain during a period of symptom remission had not been investigated and could offer a candidate mechanism to explain symptom recurrence. The overall aim of this thesis was to investigate the control of the deep and superficial fibres of the lumbar multifidus muscles in people with recurrent unilateral low back pain during a period of symptom remission and in healthy pain-free individuals. Specific recordings of deep and superficial fibres of the lumbar multifidus activity were made using intramuscular electromyography during internal (Studies I: Chapter 4 and III: Chapter 6; rapid upper extremity movements) and external postural perturbations (Study II: Chapter 5; predictable and unpredictable trunk loading) with varying levels of cognitive demand (Study III: Chapter 6) and preparation for trunk loading (Study II: Chapter 5). The behaviour of the lumbar multifidus was also investigated using ultrasound imaging during voluntary lower limb movements commonly used to challenge trunk control in low back pain populations (Study IV: Chapter 7). These studies showed temporal and spatial differences in the control of the deep and superficial fibres of the lumbar multifidus muscles in people with recurrent unilateral low back pain during a period of symptom remission compared to healthy pain-free individuals. Temporal differences (Study I: delayed onset of deep multifidus activity relative to the onset of deltoid activity) are present bilaterally but greater on the previously symptomatic side. Spatial differences (Study II: decreased amplitude of deep multifidus activity and earlier onset of peak superficial multifidus amplitude prior to predictable trunk loading) are also present bilaterally but differed between the previously symptomatic and non-symptomatic sides. However, spatial differences were not affected by increased cognitive demand (Study III: no difference in the amplitude of the deep or superficial fibres of the lumbar multifidus during internal postural perturbations with increased cognitive demand). Ultrasound imaging also showed differences in lumbar multifidus behaviour between these two groups during performance of a lower limb movement (Study IV: greater increase in multifidus percentage thickness change during the prone straight leg raise in people with a recurrent low back pain during symptom remission compared to healthy pain-free individuals). Our findings show that differences are present in the control of the lumbar multifidus between people with recurrent low back pain during symptom remission and healthy pain-free individuals. These findings support the notion that there are differences in the strategy used by the nervous system to control spinal motion in people with recurrent low back pain. These findings are consistent with therapeutic exercise programmes attempting to restore the control of specific components of the paraspinal muscle group. Finally, these findings suggest that despite the resolution of symptoms paraspinal muscle function is not restored and could offer a candidate mechanism to explain symptom recurrence.

THE BENEFITS AND INJURY RELATED HARMS OF PHYSICAL ACTIVITY IN CHILDREN AGED 5-12 YEARS

Spinks, Anneliese Barclay — 2008-11-21T00:00:00Z

Background: The prevalence of overweight status amongst Australian children has increased substantially and now approximates one quarter of the paediatric population. Proponents of physical activity have argued that this increase in partly due to decreasing activity levels, coinciding with an increase in sedentary behaviour. Consequently, a public health agenda to increase physical activity participation has emerged and Australian guidelines were published in 2004, recommending that children aged 5-12 years participate in a minimum of 60 minutes of physical activity daily and spend no more than two hours a day using electronic media for entertainment. However, an unintended consequence of physical activity is exposure to the risk of injury. To date, these risks have not been quantified in primary school aged children despite injury being a leading cause for hospitalisation and death in this population. Furthermore, the protective effect of sufficient physical activity against obesity remains uncertain, with a lack of consensus of an independent relationship between activity and weight status. A clearer understanding of the relationship between physical activity and the positive and negative outcomes is therefore warranted to inform public health policy and ensure that the potential benefits of increased activity participation amongst the paediatric population will not be outweighed by the risks and costs of injury. Aims: There were five main aims of the thesis: 1. To describe the distribution of BMI in children 5-12 years by age, sex and SES 2. To quantify the association between physical activity and obesity in children 5-12 years 3. to describe the distribution of physical activity participation in children 5- 12 years by age, sex and SES. 4. To describe the physical activity specific incidence of injury in children 5- 12 years, by age, sex and SES 5. To quantify the association between categories of physical activity and injury type sustained. Method: The Childhood Injury Prevention Study (CHIPS) was a prospective cohort study that collected data from a randomly selected sample of Brisbane primary and pre-school children aged 5 to 12 years. Data for each participating child were available for the following variables: age, gender, body mass index (BMI), socioeconomic status (SES) indicators (household income, maternal education, school area SES), family size, home play equipment availability, transport method to school, estimated time per week in various types of physical activity and sedentary leisure activities, and incidence of injury recorded prospectively over 12 months. Analytic strategies Logistic regression analysis was performed to 1) determine the protective effect of compliance with the Australian guidelines against obesity. 2) identify variables that were associated with insufficient (< 60 minutes) daily activity. The age and gender distribution of injury rates per hourly exposure were calculated for all activity and for organized, non-organised and common specific activities occurring outside school hours. Additionally, child-based injury rates were calculated for physical activity related injuries both in and out of the school setting. Results: Compliance with physical activity guidelines and protection against overweight status Approximately 20% of the cohort was considered overweight according to international age standardised BMI charts. Non-compliance with activity guidelines was 15% for out of school physical activity participation, and 31% for excessive electronic media entertainment use. Non-compliance with the minimal physical activity guideline increased the odds of being overweight by 28%, however this difference was not statistically significant. There was, however a significant 63% increase in the odds of overweight status amongst children who overused electronic media for entertainment. Children failing the minimum activity participation recommendation were less likely to walk or cycle to school (adjusted odds ratio (OR) 0.43; 95% CI = 0.24 0.77) or participate in organised sports or activity (OR 0.42; 95% CI = 0.28 0.64) and were more likely to spend in excess of 2 hours a day watching television of using a computer for entertainment (OR 2.10 (1.16 3.78). Harms of physical activity: exposure to injury risk A high number of injuries (89%) sustained by the cohort were directly related to physical activity and 34% of physical activity related injuries required professional medical treatment. Analysis of injuries occurring outside of school revealed an overall injury rate of 5.7 injuries per 10 000 hours of exposure to physical activity and a medically treated injury rate of 1.7 per 10 000 hours. The highest injury risks per exposure time occurred for tackle-style football, wheeled activities and tennis. Conclusion: One in seven children from the Greater Brisbane area are at risk for being insufficiently active according to Australian national guidelines whilst a third overuse electronic media. Given that overuse of electronic entertainment was positively associated with childhood obesity, these children should be the target of public health campaigns to promote alternative leisure time activities. Injury rates per hours of exposure to physical activity were low with less than 2 injuries requiring medical treatment occurring for every 10 000 hours of activity participation outside of school.

THE BENEFITS OF PEER TUTORING IN A GRADUATE ENTRY MEDICAL PROGRAM

Ian Jones — 2010-11-15T00:00:00Z

ABSTRACT Helping students learn is faculty’s raison d’etre. There are many ways to achieve this aim including the increasingly popular method of peer tutoring where a social and situational model of learning is championed. This study used such a model in the Success Promotion Program (SPP) and was compared with three “academic knowledge” peer tutoring programs, the Supplemental Instructional Project (Hurley et al, 2003), Peer Assisted Study Sessions (Playford, Miller & Kelly, 2002) and Supplemental Instruction (Blanc, DeBuhr & Martin, 1983), rather than “clinical skill based” peer tutoring programs. SPP assessed the effect of peer tutoring on students in the Year Two MBBS Program and their peer tutors recruited from the Year Three MBBS Program at The University of Queensland during 2005. Comparisons were made between the perceived study characteristics and interpersonal connections for those students and tutors who participated in SPP and a control group who did not participate in SPP. The aim was to determine if there were differences between these groups and if participation changed participants’ end of year summative assessment cohort ranking compared with their previous performance in the medical course. SPP promoted collaborative learning and engaged participants in valued learning experiences, encouraged constructive discussion, guided participants to helpful references and assisted them to control their own learning, all in a non-threatening environment. Peer tutors were able to pass on their experiences of learning in the MBBS Program. Students appreciated peer tutors’ ability to teach at an appropriate level and both tutor and students reported benefiting from this co-operative and symbiotic relationship. Combinations of quantitative and qualitative methodologies were used, including Approaches to Learning Inventory, a modified Grasha-Ichiyama Psychological Size and Distance Scale, and structured and free response questionnaires. Both students and tutors completed these questionnaires during the study. At the beginning of Year Two of the MBBS Program, student study characteristics were similar and in accord with a deep approach to learning. Neither gender, nor number of SPP sessions attended by students, changed their study characteristics. Overall, it was not possible to show significant differences in study characteristics between participating and control students. This occurred because each group had passed the same selection process, had similar levels of academic performance and used similar study methods. However, where it was possible to compare student study characteristics at the beginning and end of the year, it was found that students moved away from a deep to a surface approach to learning as examinations approached. Students’ interpersonal connections with tutors did not influence their end of year academic ranking. Benefits from participation in the Success Promotion Program (SPP) were revealed by those students who attended ten or more sessions. They demonstrated a need for relevant information, an understanding of core material and discovering where this core material fitted into clinical practice. This group of students enjoyed working cooperatively with their peers, sharing information and resources, and not being left completely to their own devices to master the MBBS Program. All these needs were met by SPP, plus they increased their academic ranking at the end of year more than those who attended fewer or no SPP sessions. In addition, students who participated in SPP had lower failure rates in the end of year examinations than non participants. Tutors favoured a deep approach to learning, put much effort into their studies and monitored how they studied. They did not alter these learning behaviours during the study. Tutors rated their expertise higher against SPP students and increased these ratings as the year progressed. Interpersonal connections did not influence tutor academic outcomes, nor whether they were rated by students as outstanding tutors. High academic rank in Year Two did not distinguish them as volunteers for peer tutoring the following year. The Success Promotion Program (SPP) was compared with three “academic knowledge” peer-tutoring programs and revealed similarities of program aims, but differences between the academic levels of participating students, tutor selection, range of subjects taught, and program duration. The academic level of SPP students and tutors was more advanced than the three comparator peer tutoring programs; tutor selection was not confined to “A-grade” volunteers; the number of academic subjects tutored at any one time was high, and spanned the academic year. Study positives far exceeded negatives and participants reported how learning was enriched by peer tutoring. The study demonstrated the impact and relevance of social aspects of teaching and learning. These attributes are predicted to be of benefit for these students throughout their medical careers. SPP has made a contribution to understanding how students and tutors learn and develop their self directed learning behaviours. However, the MBBS Program assessment procedures do not measure which learning behaviours students use, and was considered one reason why it was not possible to demonstrate a link between learning behaviour and examination outcome. Seeing SPP participants taking new opportunities to learn and then reap the rewards of their efforts by passing their summative assessments was pleasing. At the time of writing these students and tutors are now qualified doctors. Here they continue to seek and understand new knowledge, employing skills that they learnt at Medical School and during the Success Promotion Program. Their future is bright, and their quest for knowledge continues.

The biological and molecular characterisation of the Defective embryo and meristems (Dem) gene family

Matthew, Louisa. — 2007-08-24T00:00:00Z

The bio-logic of venom complexity: A chemical and evolutionary investigation into the role of venom complexity in two orders of venomous animals

Morgenstern, David — 2013-04-19T12:59:13Z

The biology and behaviour of Culicoides brevitarsis kieffer (Diptera: Ceratopogonidae) : with particular reference to those features essential to its laboratory colonisation.

Campbell, Malcolm McLachlan. — 2011-07-23T00:00:00Z

The biology and characterisation of the ascoviruses (Ascoviridae: Ascovirus) of Helicoverpa armigera Hubner and Helicoverpa punctigera Wallengren (Lepidoptera: Noctuidae) in Australia

Newton, Ian Russell — 2007-08-24T00:00:00Z

The Biology and Conservation of Gorgonian-Associated Pygmy Seahorses

Richard E. Smith — 2011-03-17T00:00:00Z

Pygmy seahorses are a little known, morphologically and ecologically distinct group of syngnathid fish. Reaching a maximum standard length of 26.9 and 24 mm respectively, Bargibant’s (Hippocampus bargibanti) and Denise’s pygmy seahorses (H. denise) are amongst the smallest of seahorses. They are also extreme habitat specialists living in an obligate association with certain gorgonian corals of tropical Southeast Asian reefs. The dissimilarities from their larger congeners, the extent of anthropogenic pressures within their geographical range and their listing by the IUCN Red List of Threatened Species as ‘Data Deficient’ highlight the need for targeted study. The aim of this thesis was to conduct the first biological examination of gorgonian-associated pygmy seahorses, elucidating the population structure, behaviour and potential threats to the species. The study site was a marine protected area created and administered by a SCUBA resort in southeast Sulawesi, Indonesia. Population size and structure of H. bargibanti and H. denise, were estimated at seven sites and five depth contours. Within the 7,000 m2 of reef surveyed by belt transect, the densities of both species were very low (H. bargibanti: 0.34 (± 0.16 S.E) 200 m-2, H. denise: 1.18 (± 0.20) 200 m-2). Their densities were amongst the lowest for an unexploited seahorse population. The more host specific and rarer, H. bargibanti, which lives exclusively in association with Muricella spp. gorgonians, was found on 20.0% of potential hosts but the density of hosts was low (0.72 (± 0.1) 200 m-2). The more common H. denise is reported to be comparatively cosmopolitan in host choice but within transects at this site was exclusively found inhabiting the relatively common Annella reticulata gorgonians (7.60 (± 0.8) 200 m-2), with 7.8% of gorgonian colonies of that species inhabited. Group sizes ranged between 1 and 6 individuals and sex ratios were in some cases skewed. The isolation of pygmy seahorses on a gorgonian host and the occurrence of variable group sizes were hypothesised to act as selective pressures on the ecology of gorgonian-associated pygmy seahorses. To investigate this, focal observations were conducted on the social and reproductive behaviour, space use and activity levels of 18 (9 Male: 9 Female) adult H. denise in four groups of different sex ratios and numbers of individuals. During 217 thirty-minute observation periods monogamy was observed to be the prevalent mating system but social polygamy and sequential polyandry were recorded in certain instances where sex ratios were skewed. Conventional sex roles were observed, with males competing for access to females. Small (150-1508 cm2) and strongly overlapping (by 2-5 individuals) home ranges, measured using minimum convex polygons, were observed and in no instances were seahorses observed away from their gorgonian host. Sites of concentrated use, or core areas, were observed and coincided with protected areas of the host. Nocturnal use core areas were usually shared by reproductive partners and were the site of social and reproductive behaviours. The ecology of H. denise appears to maximise reproductive output through mating system plasticity and early maturation of animals. Complementing the ecological studies I explored the role of gorgonian-associated pygmy seahorses in ecotourism through diver surveys and observations. Almost a third of survey respondents (30.8%) listed pygmy seahorses as one of the three underwater organisms they most wished to see during their stay at a dedicated SCUBA diving resort. The majority (88.9%) did see pygmy seahorses and of the 57.3% of respondents that used underwater photographic equipment 73.8% took images of them. Diver observations indicated that photographic activities led to the majority of contacts with the reef (72.2%) when in the vicinity of pygmy seahorses. Many of these contacts (29.2%) were with the focal pygmy seahorse’s gorgonian host directly. Use of a constant light source to highlight the animals and physical contact made with the gorgonian were found to be significant predictors of pygmy seahorse avoidance behaviours. Survey respondents were overwhelmingly in favour (91.8%) of Code of Conduct guidelines to minimise diver impacts on pygmy seahorses. Without management intervention pygmy seahorse-related ecotourism is likely to cause harm to both the seahorses and their gorgonian hosts. This research is the first of its kind into the ecology of pygmy seahorses: a group of biologically distinct and economically valuable species. My findings indicate that exceedingly low densities of H. bargibanti and H. denise, extreme habitat specialisation, high levels of habitat degradation coupled with pressure from dive tourism threaten seahorse populations. This study highlights the need for conservation and management of these species to prevent overexploitation and localised extinctions from loss of suitable gorgonian hosts.

The biology and control of ergot (Claviceps africana) in sorghum

Bhuiyan, Shamsul Arafin. — 2007-08-24T00:00:00Z

The biology and ecology of Ponyfish (Leiognathidae) in the Gulf of Carpentaria, Northern Australia

Smith, Jonathan Staunton. — 2007-08-24T17:47:51Z

The Biology and Population Ecology of Nautilus pompilius at Osprey Reef, Coral Sea and the conservation implications of international Nautilus fishing

Andrew Dunstan — 2012-01-05T00:00:00Z

The chambered Nautilus is represented by two extant genera, Nautilus Linnaeus and Allonautilus Ward and Saunders. Species and sub-species of these genera are the subject of speculation as to their threatened status arising from the impacts of targeted fishing for the ornamental shell, jewellery and exotic food market. At present there is a group of nautilid experts communicating with the U.S Fish and Wildlife Service to assess whether such concerns are valid and whether any species of these two genera fit the criteria necessary for listing in the Appendices of the Convention on International Trade in Endangered Species (CITES). This PhD thesis provides current scientific information required by this expert group to enable assessment of the status of nautilid populations. This includes nautilid growth rates, population estimates, movement, localised distribution, fishery impacts and social development and livelihood values of Nautilus fisheries. It also provides a new insight into the life of Nautilus in the wild. Trapping for Nautilus was conducted at Osprey Reef (Coral Sea, Australia) from 1998 - 2008, on 417 occasions, with 2673 individuals of one species, Nautilus pompilius, captured and 252 individuals recaptured. Baited remote underwater video systems (BRUVS) were deployed on 15 occasions and six remotely operated vehicle (ROV) dives from 100-800 m were conducted to record Nautilus presence and behaviour. Maturity, sex and size data were recorded, while measurements of recaptured individuals allowed estimation of growth rates to maturity, and longevity beyond maturity. Sexual dimorphism in size at maturity (males: 131.9SD = 2.6 mm; females: 118.9 7.5 mm shell diameter) was described in a population dominated by mature individuals (58%). Mean growth rates of 15 immature recaptured animals were 0.061 0.023 mm day-1 resulting in an estimate of around 15.5 years to maturation. Recaptures of mature animals after more than five years provided evidence of a lifespan exceeding 20 years. Using program MARK, a small and dispersed population of between 844 and 4467 individuals (14.6-77.4 km-2) dominated by males (83:17 male:female) and comprises few juveniles (<10%) was determined for Osprey Reef N. pompilius. These results provide the first nautilid population and density estimates which are essential elements for long-term management of populations via sustainable catch models. Results from BRUVS deployments now provide confidence for their more widespread use to assess efficiently the size and density of exploited and unexploited Nautilus populations worldwide. Ultrasonic telemetry techniques were employed to track eleven specimens of Nautilus pompilius for variable times ranging from one to 78 days at Osprey Reef, Coral Sea, Australia. Combined with the observational records from ROV dives, the resulting data suggest continuous, nightly movement between depths of 130 to 700 m, with daytime behaviour split between either stasis in relatively shallow (160 to 225 m) depths and active foraging in depths between 489 and 700 m. The findings also extend the known habitable depth range of Nautilus to 700 m, demonstrate juvenile distribution within the same habitat as adults and document daytime feeding behaviour. These data support an hypothesis that, contrary to previously observed diurnal patterns of shallower at night than day, more complex vertical movement patterns may exist in at least this, and perhaps all other Nautilus populations. The studies of Nautilus pompilius at Osprey Reef reveal that this unexploited population is stable from a catch per unit effort (CPUE) basis over 10 years. In contrast, data from a detailed interview questionnaire of Nautilus pompilius fishers and traders in Palawan, Philippines highlight a fishery that is unsustainable. The results from the Philippines show up to 80% declines in reported CPUE from 1980 to the present, fewer than two Nautilus generations, which can be attributed to fishing pressure. Questionnaire responses suggested there is no cultural or historical relevance of Nautilus fishing to local Palawan communities and the fishery only provides approximately 10 - 20 years of economic return before becoming non-viable. Identification of new Nautilus fishing sites and training of locals by buyers from distant depleted fishing areas illustrate how the demand for Nautilus shells has generated this fishing pressure. These findings demonstrate that the Palawan population of Nautilus pompilius fits the criteria for listing as ‘ENDANGERED’ in the International Union for Conservation of Nature (IUCN) Red List and fulfils the requirements for listing within Appendix 1 and 2 of CITES. This project has also developed the techniques to allow rapid and cost-effective estimation of nautilid population density and to gather valuable survey data on fishery catch rates and social value of fishing to the community. The use of Baited Remote Underwater Video Systems is proposed to measure attraction times, numbers and speed of movement of Nautilus to ultimately determine population density and to derive population estimates. These methods form the basis for future research proposed to fill the gaps in knowledge of chambered Nautilus and Allonautilus required for informed decision-making about conservation management.

The biology, epidemiology and variability of Quambalaria shoot blight of Corymbia species

Geoffrey Pegg — 2011-07-05T00:00:00Z

The recent need to develop a source of high value logs for sawn timber products to replace the declining supplies from native forests has resulted in the rapid expansion of spotted gum plantations in Queensland and northern New South Wales. Quambalaria shoot blight, caused by the fungus Quambalaria pitereka, is a serious disease affecting this expansion (Simpson, 2000; Self et al., 2002; Carnegie, 2007b; Pegg et al., 2008). This study aimed to develop a disease management strategy through investigating aspects of the pathogens biology. Initially we aimed to determine which species of Quambalaria are associated with shoot blight symptoms on Corymbia spp. Surveys identified three Quambalaria spp. — Q. pitereka, Q. eucalypti and Q. cyanescens — from native and plantation eucalypts as well as amenity plantings. Symptom descriptions and morphological studies were coupled with phylogenetic studies using ITS rDNA sequence data. Quambalaria pitereka was the causal agent of blight symptoms on species and hybrids in the Corymbia complex. Quambalaria eucalypti was identified from Eucalyptus species and a single Corymbia hybrid. Quambalaria cyanescens was detected from native and plantation Corymbia spp. Quambalaria spp. are pathogens of growing global importance, yet virtually nothing is known about the manner in which they infect and colonise their hosts. A study of the infection process of Q. pitereka and Q. eucalypti on Corymbia and Eucalyptus species was thus undertaken using light, scanning and transmission electron microscopy after artificial inoculation. For both species, conidial germination was triggered at relative humidity (RH) levels above 90 % and commenced within 2 hours in the presence of free water. Light reduced the percentage germination but did not prevent germination. Conidial germination and hyphal growth occurred on the upper and lower leaf surfaces with penetration occurring via the stomata or wounds on the leaf surface or juvenile stems. There was no evidence of direct penetration of the host epidermis. Following penetration through the stomata, hyphae of Q. pitereka and Q. eucalypti grew only intercellularly without the formation of haustoria or any other interaction apparatus. Instead, the presence of an interaction zone is demonstrated in this thesis. Conidiophores arose through stomatal openings and produced conidia seven days after infection. Incorporation of screening for resistance to Q. pitereka into current breeding programs is essential for the future development of plantations using spotted gum and Corymbia hybrids. An additional part of this study was to determine whether there is variability in susceptibility to infection by Q. pitereka among different species and provenances of spotted gum and to identify variability among and within families of spotted gum. We also considered whether the seed source origin is a significant indicator of susceptibility. Assessments were conducted in trials consisting of spotted gum provenances, families and clones, all at the same site and with high levels of disease pressure and with optimum climatic conditions for disease development. While all species and provenances of spotted gum could be infected by Q. pitereka, results showed that there are high levels of variability in susceptibility among and within species, provenances and families, indicating the potential to select for disease resistance. Provenance was shown to be an unreliable indicator of susceptibility to Q. pitereka. A spotted gum clonal trial provided the opportunity to investigate the impact of the disease on tree growth and factors influencing wood quality. The effect of Q. pitereka on productivity when infection occurs during plantation establishment and the value of deploying resistant germplasm were determined. The results showed that Q. pitereka has a significant impact on plantation establishment and emphasised the negative impact on wood quality and value in sawlog production where unimproved or incorrectly selected germplasm is deployed. Tree growth, based on height and diameter as well as tree form, was significantly improved where germplasm with low susceptibility to Q. pitereka infection was used. Disease development within plantation-grown spotted gum was examined and an understanding of the epidemiology of Q. pitereka and factors influencing disease development established. It was shown that native spotted gum is a primary source of inoculum, followed rapidly by the production of secondary inoculum from infected trees in the plantation. The rate of spread and development of Q. pitereka within plantations increased exponentially over time as additional trees became infected and produced secondary inoculum. Spore concentration was shown to play an important role in disease development with disease severity increasing with increasing disease incidence on individual trees and incidence across the plantation. An understanding of pathogen variability and host-pathogen interactions is needed to develop management strategies for the disease. The aim of the study was to determine if there was any difference in host range of Q. pitereka isolates and any variability in aggressiveness of these isolates. It was evident for the first time that Q. pitereka isolates differ in their level of aggressiveness towards hosts. Of the isolates tested, two were consistently more aggressive, based on incidence and severity of disease and lesion size, on spotted gum species and C. torelliana.

The Biology of Nod2

Barry, Guy — 2008-11-21T00:00:00Z

The NOD-LRR (nucleotide-binding oligomerization domain, leucine-rich repeat) family of proteins in mammals form part of a wider, extremely well conserved pathogen detection system that includes the CED (cell death abnormality) proteins in C. elegans and the pathogen-detecting disease resistance (R) proteins in plants. The mammalian NOD-LRR protein Nod2 has been shown to mediate NF-KE! activation upon activation by MDP (muramyl dipeptide), a breakdown product of bacterial cell walls, and is thought to form part of the innate host defense system. This protein was isolated as a susceptibility gene for Crohn's disease (CD), an inflammatory bowel disease (IBD), and to Blau syndrome (BS) which is characterised by early-onset granulomatous arthritis, uveitis and skin rash with carnptodactyly. Data presented in this thesis shows Nod2 mRNA significantly increased with TLR ligands and far less by MDP. The combination of these ligands resulted in an additive effect of Nod2 mRNA production, as examined using real-time PCR, indicating that separate signalling pathways could exist for TLR ligands and MDP. Microarray data showed overlapping, but not exact, gene sets for LPS and MDP, and that MDP induced gene expression at a slower rate than LPS. Furthermore, MDP alone had no observed effect in MTT assays and osteoclast formation using RAW264.7 cells, but the combination of MDP and TLR ligands proposed potential links to apoptosis and osteoclastogenesis respectively. Together these data suggest the need for an initial stimulus for the priming of Nod2. Whereas most of the mammalian Toll-like receptors (TLR) span the cell membrane and bind extracellular pathogen-associated molecular patterns (PAMPs), Nod2 is cytoplasmic. As it is proposed to play a role in the intracellular PAMP detection system the intracellular location is an important issue. In this thesis it is shown that Nod2 is part of a large cytoplasmic protein complex. and not associated with a membrane-bound organelle such as the endosomal compartment. Attempts to identify intracellular partners of Nod2, with an MDP responsive, V5-His-tagged full length construct, have not been successful to date. Stimulation of Nod2 by MDP has been shown to activate NF-a, linking Nod2 to the inflammatory process, and CD-associated mutants lack this ability. This would seem to contrast the phenotype of CD in patients, exhibiting excess levels of NF-KJ3 and other inflammatory mediators. However, the activation of NF-KB can be part of a negative regulatory pathway. Protein expression in baculovims of the possible dominant-negative LRR domain of Nod2 was suspended after the protein was found to be insoluble and usable amounts were not able to be produced.

The biology of Parthenium hysterophorus L. in Australia

Navie, Sheldon (Sheldon C.) — 2007-08-24T18:12:34Z

The biology of Protasparagus Africanus (Lam.) Oberm. in eastern Australia

Stanley, T. D. (Trevor D.) — 2013-03-14T09:58:42Z

The biopsychosocial implications of helicobacter pylori infection in adults with intellectual disability

Wallace, Robyn A. — 2011-05-18T16:55:51Z

The Biosynthesis of pyrimidines by escherichis coli.

Back, Kenneth John Campbell — 2010-07-20T00:00:00Z

The Blue Poppy Sea: reflections on writing from the leaky boat of an ethnographic novel

Jennaway, Megan Gayle — 2011-02-25T00:00:00Z

The breakage of mineral particles in ball mills

Bush, P. D. — 2010-08-31T00:00:00Z

The Buddha's Second Renunciation: doubt, groundlessness and autonomy in contemporary Western Buddhism

Martin Kovacic — 2009-12-07T00:00:00Z

This thesis addresses a major trend (what might be termed a “post-Buddhism”) within contemporary Western Buddhist thinking, and hence practice, emphasising the epistemic, existential and ethical autonomy of self as it engages with the Asian Buddhist traditions. Aligning its enquiry with a corresponding hermeneutic of the Buddha‘s biography in his “second renunciation” (his social-psychological and praxiological relinquishment of the structures of religious authority) it focuses on the work of contemporary Western dharma teachers Stephen Batchelor, David Loy and Alan Clements. Their respective emphases of agnostic doubt, ontological groundlessness, and existential-ethical autonomy are investigated in turn, alongside a corresponding reading of the Buddha‘s praxis prior to his enlightenment. Of interest to academic Buddhist Studies, this analysis introduces potential re-theorisations of the meta-epistemic nature of Buddhist praxis and the phenomenology of self and Buddhist ‘non-self’ as it/they engage with both Buddhist and Derridean deconstructive (contemplative and intellectual) praxis. It also considers a re-contextualisation of Buddhist ethics as it is influenced by the deconstructive and ethical strategies of Derrida and Levinas, as well as a (native but under-explored) Buddhist ‘ethics of non-duality.’ (All of these themes might be seen as more or less implicit also in the work of Western Buddhist theorists such as Roger Jackson, John Makransky, José Ignacio Cabezón, Alan B. Wallace, John Pickering and so on, and their deconstructionist counterparts in John Caputo, Robert Magliola, Steven Laycock, Carl Olson and others.) The thesis concludes with a general theorisation of the newly-inflected models of Buddhist enlightenment, praxiology and ethical engagement that necessarily emerge from such a shift of emphasis: a post-secular, non-hierarchical trans-religious culture of self-determination both within and without tradition. The Buddha‘s enlightenment itself emerges as a heterogeneous culture of human freedoms rather than a form of univocal religious transcendence. Similarly, Batchelor, Loy and Clements’ concerns around authenticity can be seen as productive elements of an evolving model of Buddhism within Western culture: one that in paradoxically grounding itself in ‘groundlessness,’ returns to the meta-religious roots of Gotama Buddha‘s own socio-historic transformation of the (religious and other) conditions of his time. Such a transformation becomes characterised by a greater attention to the contingencies of the unique self and its environment, knowledge-acquisition and its constructed character, justice and ethical ambiguity, and the indeterminacy of normative religious claims.

The Bundaberg Volcanic Province : field relations, petrochemistry, and tectonic setting

Robertson, Allan Douglas Cowie. — 2011-09-21T00:00:00Z

The burden of major depressive disorder on significant others : an examination of the objective and subjective burden on significant others of patients with major depressive disorder, and the effectiveness of a brief cognitive behavioural based interventi

Walters, David. — 2011-08-16T00:00:00Z

The capacity for reform

Eccleston, Richard. — 2007-08-24T00:00:00Z

The cardiovascular effects of the toxin(s) of the Australian paralysis tick, Ixodes holocyclus

Campbell, Fiona Elizabeth — 2007-08-24T17:57:20Z

The Catalytic Mechanism of SoxAX Cytochromes: Insights from Site-directed Mutagenesis, Spectroscopy and Enzyme Kinetics

James Kilmartin — 2012-06-28T00:00:00Z

The SoxAX cytochromes are part of a multi-enzyme complex that catalyses the oxidation of reduced sulfur compounds. The diheme SoxAX cytochrome from Starkeya novella is a critical component in the bacterial sulfur oxidation pathway and catalyses the covalent attachment of thiosulfate to the SoxYZ carrier protein. The highly unusual His/Cys ligated heme group found within the SoxA subunit is believed to be the active site of SoxAX, however, the extremely low SoxA heme redox potential and the presence of a Cu(II) redox centre raised many questions regarding the role of the SoxA heme and Cys236 in the reaction mechanism of SoxAX. In this study we substituted Cys236 with other well-characterised heme ligands (methionine and histidine), to create different heme ligand environments with which to investigate the proposed function of Cys236. The substituted SoxAX proteins were spectroscopically analysed by near infra red magnetic circular dichroism (NIR-MCD) and electronic paramagnetic resonance (EPR) spectroscopy in order to fully characterise the ligand sphere surrounding the SoxA heme before determining the kinetic parameters of each using the recently developed reduced glutathione (GSH) assay system. The initial characterisation of the SoxA heme ligand environment involved UV-vis absorption and NIR-MCD spectroscopy, as well as optical heme redox titrations, and the results corresponded to what was expected based on the literature. The exception was SoxAXC236A; the presence of a high spin SoxA heme group could not be confirmed based solely on these results. The use of EPR increased the resolution of our ligand field characterisation and demonstrated multiple low spin heme species for SoxAXC236M and SoxAXC236H, as well as the presence of a small amount of high spin heme. Analysis of the SoxAXC236M protein crystal structure revealed variability in the bond lengths between the axial ligands and the Fe3+ ion centre. It can be concluded that the heme heterogeneity observed in the EPR spectra arises from multiple conformations of the heme ligands. Unlike the other Cys236 substituted proteins, the EPR spectrum of SoxAXC236A revealed virtually no high spin heme signal intensity, instead a low spin species was identified indicating a new heme ligand has coordinated to the SoxA heme. Taken together, the EPR data for SoxAXWT and the Cys236 substituted proteins demonstrates an inherent flexibility in the local SoxA heme ligand environment, which may be an important property in the reaction mechanism of SoxAX. The creation of Cys236 substituted proteins allowed, for the first time, an opportunity to test whether properties of the SoxA such as the heme redox potential or the nature of the heme ligands are critical for the SoxAX reaction mechanism. Utilising a recently developed assay system that uses reduced glutathione as a substrate, we have demonstrated neither the heme redox potential nor the nature of the heme ligands of the SoxA heme has any significant impact on the substrate binding affinity. However, a noticeable decrease in the kcat values indicates that Cys236 is necessary for efficient enzymatic turnover. It is possible that this is due to the Cys236 interacting with the substrate and requires the conformational flexibility demonstrated in the EPR spectroscopy. The results then demonstrate that the substitution of Cys236 with other heme ligating residues has no significant affect on the glutathione binding affinity and is further evidence strengthening the hypothesis that the Cu(II) site is the active site of SoxAX.

The Causes for the Poor Flotation Performance of a Double-Refractory Gold Ore

Reyhaneh Hosseini Tabatabaei — 2012-03-08T00:00:00Z

The recovery of gold from certain Carlin-type deposits, with numerous perceived and real recovery problems is quite challenging. These deposits are characterised as “double-refractory” because most of the gold values are locked in sulphide minerals (e.g. pyrite and arsenopyrite) and, therefore, cannot be leached directly with cyanide; pre-concentration of sulphide minerals by flotation followed by either roasting or pressure oxidation is necessary. Furthermore, these ores contain varying amounts of carbonaceous matter which is known to cause “preg-robbing” in the cyanidation stage that must be removed before cyanidation. Despite the numerous studies that have been performed on double-refractory gold ores in many laboratories globally, recovery of sulphide minerals remains low and selective separation between sulphide minerals and carbonaceous matter is quite poor. A review of the published literature on double-refractory gold ores showed that the reasons for their poor separation and recovery by flotation are unknown and that no detailed study investigating the causes of this behaviour has yet been conducted. This thesis investigated the possible causes for the poor flotation response and separation selectivity of a double-refractory gold deposit owned by Barrick Gold Corporation (Goldstrike deposit, BR-22 ore). It was hypothesized that “The poor flotation response and selective separation of gold-bearing minerals in the Goldstrike double-refractory gold ore are mainly caused by certain non-sulphide gangue species, and can therefore be rectified in principle by an appropriate alternative processing strategy for separating the deleterious species from the value species”. To address this hypothesis, a comprehensive suite of analytical techniques including fire-assay, inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray Diffraction, optical microscopy and image analysis techniques (Mineral Liberation Analyser) were used for detailed chemical and mineralogical characterisation of the ore. The distribution of gold in different gold bearing minerals was also identified using diagnostic acid leaching methods. Preliminary flotation experiments were performed to improve the flotation recovery and separation selectivity of the ore. To address the hypothesis a novel experimental design strategy was developed and applied. A gravity separation technique (i.e. Mozley separator) in conjunction with a tailored mixture experimental design was used to first isolate/separate mineral components, blend the separated mineral components in controlled proportions and characterize the blends metallurgically using flotation. In the course of the use of this suite of techniques, the effect of certain gangue minerals and mineral associations on the flotation response of the ore was studied. Through the detailed chemical and mineralogical characterisation of the ore, it was found that in order to obtain the adequate degree of liberation, the ore needed to be ground to a very fine P80 of approximately 20 µm. But the preliminary flotation performance (i.e. recovery and separation selectivity) of the fine-grind Goldstrike double-refractory gold ore was quite poor and non-selective despite the minerals of interest being almost fully-liberated. The results of the flotation experiments on the blended components of the ore supported the hypothesis and showed that even a small increase in the mass proportion of non-sulphide gangue minerals had a detrimental effect on the recovery of sulphides and separation selectivity. The very fine size distribution and extensive free surface area of the existing non-sulphide gangue minerals especially clays and carbonates had a noticeable effect on the flotation recovery and separation selectivity of the ore. Therefore, it is postulated that effect of non-sulphide gangue minerals on the surface/pulp chemistry of sulphide minerals caused by existence of fine and fully-liberated non-sulphide gangue minerals may be the reason for the low recovery and poor separation selectivity of the gold bearing minerals. It is recommended that a comprehensive surface chemistry study be conducted for investigating the adsorption of reagents and oxidation on the surface of minerals. Also, spiking flotation experiments as a tool for examining the extent effect of non-sulphide gangue minerals (carbonaceous matter, clays and carbonates) on the flotation performance of sulphides should be considered. Moreover, by combining spiking tests with a surface chemistry study, it may be possible to understand the underlying mechanism of the adverse effect of certain gangue minerals on flotation performance of the double-refractory gold ore type. Finally, as a quick approach for increasing the recovery of sulphides before these additional studies, separation of non-sulphide gangue minerals especially clays and carbonates prior to the sulphide flotation stage is suggested for the Goldstrike double-refractory gold ore.