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

The dynamics of teaching and learning in the struggle for liberation in 20th century South Africa

Purdon, Ailsa Jean — 2013-01-07T17:19:32Z

The early development of the health services of Papua New Guinea, 1870-1939

Spencer, Dora Margaret — 2008-11-21T00:00:00Z

This is an account of the two administration health services, and of those provided by the missions, through three succeeding regimes in British New Guinea/Papua and four successive regimes in German New Guinea/Territory of New Guinea. It also traces the evolution of Australian health administration in relation to the health services of Papua and New Guinea. Because the missions - although subsidised by the Administrations - developed medical services of their own before and quite separate from the administration services they are considered separately. Development of the health services was affected by the considerable constraints of insufficient finance, unfamiliar terrain, unfamiliar peoples and unfamiliar diseases. It was also affected by the emergencies of recurring epidemics of introduced diseases, by the interruption of the First World War and by the crisis of the Great Depression years. While in spite of the war years development was more or less continuous in Papua, New Guinea suffered almost complete disruption of health services for seven years, except to military personnel, during the years of occupation by Australian troops between 1914 and 1921. Nonetheless before the 1930s both the Papua and New Guinea health services were stable and expanding. Increasingly they were able to retain medical staff and to send officers to Australia for postgraduate training in tropical medicine and hygiene: also to undertake increasing medical training and dispersal of both European Medical Assistants and indigenous personnel on patrols and into village societies. The importance of adequate nutrition became a central issue, and continuing campaigns were conducted against hookworm, yaws, gonorrhoea and leprosy. The period of eighteen years between the establishment of Australia's Commonwealth Department of Health in 1921 and 1939 included an exploration of Australia's potential role in relation to health matters in Papua and New Guinea and more widely in the Pacific Region. The first, and a significant, contribution was that made by the Commonwealth Health Laboratory in Rabaul. As possibilities were explored and tried, or discarded, it became clear that the best means for Australia to assist in the health problems of the two Territories was by providing appropriate training for medical and other health personnel and for missionaries, and by conducting field surveys and research to help elucidate the epidemiology and pathology of diseases and questions of entomology. Other appropriate action was the initiation and conducting of international conferences on health matters of common concern, and the undertaking of the receipt and distribution of epidemiological intelligence for the Austral-Pacific Zone, of which New Guinea was a part. The period of the study ends in 1939, when the inevitability of war, and the likely inclusion of New Guinea in the conflict, became apparent.

The ecological and evolutionary causes of call and genetic variation in the satin bowerbird (Ptilonorhynchus violaceus)

Nicholls, James A — 2013-03-08T15:36:33Z

The ecological and evolutionary consequences of genetic diversity

Aguirre, J. David — 2012-09-14T00:00:00Z

The ecological effects of the cyanobacterial toxin cylindrospermopsin

Seifert, Marc — 2008-11-21T00:00:00Z

The occurrence of nuisance growths or blooms of cyanobacteria in reservoirs and other waterbodies poses a potential risk to the quality of water as many species are capable of producing secondary metabolites that may be toxic or impart unpleasant taste and odours. Cylindrospermopsin, a potent cytotoxic alkaloid produced by numerous cyanobacteria including Cylindrospermopsis raciborskii, has gained increasing attention following its implication as the causative agent in a mass human intoxication event and numerous livestock mortalities. Cylindrospermopsin was also considered to pose significant risks to aquatic organisms, although the role of the cyanotoxin in aquatic ecosystems had received little attention. This thesis aimed to address this significant knowledge gap through a series of toxicity assays to determine the effects of the cyanotoxin in the reservoir and it receiving waters downstream within an ecological risk assessment framework. The cosmopolitan benthic cyanobacterium Lyngbya wollei, collected from Yabba Creek and the Brisbane River, was found to produce cylindrospermopsin (33 <g g-1 dry weight) and its naturally occurring analogue deoxy-cylindrospermopsin (550 <g g-1 dry weight). This is the first report of the production of the cylindrospermopsin analogues by a benthic cyanobacterium or any species of the Oscillatoriales. Screening of three other benthic cyanobacteria also identified, for the first time, toxicity associated with an Australian strain of Phormidium aerugineo-caeruleum. No known cyanotoxins were detected, although the observed effects were similar to that of neurotoxins. The comparative toxicity of the three cylindrospermopsin alkaloids; cylindrospermopsin, epi-cylindrospermopsin and deoxy-cylindrospermopsin was assessed using the brine shrimp nauplii bioassay. The toxicity of epi-cylindrospermopsin was an order of magnitude greater than cylindrospermopsin, although deoxy-cylindrospermopsin was substantially less toxic. These results compared favourably with the mouse bioassay and indicate that the hydroxyl group is required for the uptake or toxicity of the metabolite in whole organisms. The bioconcentration and bioaccumulation of cylindrospermopsin and deoxycylindrospermopsin was identified in a range of aquatic flora and fauna. Of particular interest was the discovery of cylindrospermopsin in the muscle and liver tissue of the eeltailed catfish (Tandanus tandanus) but not other fish species collected at the same site. This indicates that rather than extracellular uptake of the toxin, the source of cylindrospermopsin is dietary and possibly taken up through the consumption of freshwater bivalves. Importantly it suggests that cylindrospermopsin may be transferred through the aquatic food web. The accumulation of cylindrospermopsin in the tissue of a popular angling fish species also has implication for the exposure of humans to contaminated seafood. The toxicological effects of cylindrospermopsin and extracts of C. raciborskii were investigated through a series of acute exposure direct toxicity assessments using a floating macrophyte, green algae and a range of aquatic invertebrates from various trophic levels. Additionally, the effect of sub-lethal exposure was assessed using the growth and photosynthesis of green algae and an aquatic macrophyte, and the survival and reproductive success of the cladoceran Ceriodaphnia dubia. The effect of pure cylindrospermopsin was generally less that of C. raciborskii containing a comparable concentration of the toxin. An exception to this was the survival and reproduction of the cladoceran, Ceriodaphnia dubia, which may have benefited from increased levels of nutrition, in the form of bacteria and other micro-organisms, present in the extract. This may also explain the dominance of smaller daphnids during blooms of toxic C. raciborskii. Overall, concentrations of cylindrospermopsin required to elicit adverse effects were typically well above those which can be expected to occur in reservoirs. There is little evidence for significant ecological effects from exposure to cylindrospermopsin alone at concentrations below 100 <g L-1. However, it is likely that other bioactive compounds present in C. raciborskii extracts and cells contributed to the toxicity of the cyanobacterium. The risk posed by cylindrospermopsin alone to aquatic organisms in reservoirs and their receiving waters is therefore considered low. Water quality guidelines or trigger levels for the protection of aquatic ecosystems based solely on the cylindrospermopsin concentration may therefore not capture the potential risk of exposure to entire C. raciborskii cells. Nevertheless, a total (i.e. intra- and extracellular) concentration of cylindrospermopsin of 100 <g L-1 is suggested as an interim trigger level for the protection of aquatic ecosystems, although this should be revised following additional studies into the sub-lethal effects of chronic exposure to cylindrospermopsin and C. raciborskii.

The Ecological Function of Fish Mucus

Maxi Eckes — 2010-05-11T00:00:00Z

Ultraviolet light is damaging but fish have evolved protective mechanisms, which allows them to live in shallow water reefs, high in UV radiation. This thesis details my investigation into the physiological ecology of solar ultraviolet (UV) absorbing compounds, known as mycosporine-like amino acids found in the external epithelial mucus, and examines the supporting role potentially played by a UV-induced DNA repair mechanism in coral reef fish of the Indo-Pacific. Using reverse phase chromatography and UV spectrophotometry, I examined whether the distribution of MAA compounds across different areas of the body is correlated with differential UV exposure. Comparisons were made between the MAA content and the absorbance spectra of mucus from the dorsal, ventral, caudal and head body surface areas in five species of Scaridae (Chlorurus sordidus, Scarus schlegeli, S. niger, S. psittacus and S. globiceps) from Ningaloo Reef, Coral Bay, Western Australia. All fish analysed had at least five MAAs present, and results showed that fish had increased UV absorbance in mucus over the dorsal area, which receives the brunt of UV radiation. Little UV protection was found in mucus from the ventral area, which receives the lower level of UV radiation mostly via reflection of the sand and reef surfaces. Furthermore, UV absorbance per mg dry mucus versus standard fish length showed that there is a positive relationship in C. sordidus with increasing size. I examined whether there is a difference in the quantity of UV screening compounds found in the mucus of fish along a longitudinal geographical gradient from inshore reefs (Lizard Island, Great Barrier Reef) to the outer edge reefs to oceanic reefs (Osprey Reef). MAA absorbance increased with longitudinal distance from the mainland landmass of Australia to more oligotrophic outer reefs, where UV attenuation is reduced and the ocean is more transparent to UV wavelength. I determined that fish living on inshore, more turbid reefs where UV attenuation in shallow waters is high have lower levels of MAA protection than fish from clear oceanic reefs. Furthermore, there seems to be a direct relationship between light attenuation and exposure with the quantity of protective sunscreening found in the mucus of reef fish. It is know that UV irradiation decreases with water depth and that mucus from fish with deep habitats absorbs less UV than that of fish from shallow habitats. It is unknown however, whether this UV protection is variable within the same individuals and if so, how fast changes 11 occur. To test this, I relocated 9 ambon damselfish from a deep reef (18 m) to a shallow reef (1.5 m) to expose fish to increased levels of UV and relocated another 7 fish from a shallow to a deep reef to expose fish to decreased levels of UV. One week after relocation, all fish were returned to their original reef site to determine whether MAA levels would return to their initial levels. Fish relocated to a shallower depth were recovered and had a 60% (SD+/-2%) increase in mucus UV absorbance. Conversely, the fish relocated to a deeper depth were recovered and had a 41% (SD+/-1%) decrease mucus UV absorbance. No difference was found between UV absorbance of relocated and original fish at both depth. Six days after fish were returned to their original reef, mucus UV absorbance levels had returned to 67% +/- 4% of the original level. These results show that mucus UV absorbance is variable in individual ambon damselfish and that the sunscreen protection typical for a certain depth is reached in relocated fish within just a few days of relocation. The rate of MAA loss is higher than the accumulation of MAAs suggesting that diet is not the sole determining factor involved in the sequestration of MAAs to mucus. The cleaner fish Labroides dimidiatus performs a mutualistic service by removing ectoparasites such as gnathiid isopods as well other dead infected tissue from its clients. Cleaner fish however are also known to feed on client mucus. The benefits of eating mucus until recently were unclear. In this study, we analysed the mucus of several cleaner fish clients to determine whether mucus feeding has a nutritional advantage over gnathiids and whether cleaner fish obtain their own MAA protection through this dietary mucus ingestion. Results show that host fish that are infected with gnathiids of poor nutritional value, in contrast to those that harbour gnathiids with higher nutritional value, continuously exude mucus that has both high nutritional value and high MAA content. These findings support the conclusion that in a competitive market for cleaners some host fish are forced to offer more than parasites to cleaners. Ultraviolet light that is not filtered by UV absorbing compounds such as MAA may still lead to DNA damage such as the formation of cyclobutane pyrimidine dimers (CPDs) or 6-4 photoproducts (6-4 PPs). However, coral reef fish have alternative mechanisms to overcome UV induced damage via the photolyase DNA repair mechanisms. We experimentally demonstrated for the first time that a coral reef fish species, the moon wrasse Thalassoma lunare has the ability to repair DNA damage via photoreactivation. Fish both with and without MAA protection were irradiated with UVB wavelength to induce DNA lesions. Half of the experimental fish were then exposed to photoreactivating wavelength to induce DNA repair 12 while the other fish were blocked from the repair mechanisms. Fish which had undergone DNA repair had the lowest number of lesions regardless of mucus MAA protection. When fish were blocked from photoreactivation wavelengths MAA sunscreens clearly served a photoprotective role. The amount of damage was greatest in fish which both lacked MAAs and which were also blocked from photoreactivating wavelengths. Thus for the overall UV protection of fish both the MAA sunscreens as well as the DNA repair system play a significant role in counteracting UV damage. Ultraviolet protection by MAA sunscreens is ubiquitous in marine fish. To date the same 5 MAA compounds (palythine (λmax 320 nm), asterina (λmax 330 nm), palythinol (λmax 332 nm), usujirene (λmax 357 nm) and palythene (λmax 360nm) have been identified in the mucus of several different species of reef fish from Australia. Here we report the first evidence of the presence of additional UV absorbing compounds found in the mucus of fish from Indonesia. Using UV spectroscopy the mucus of four species of fish was compared between both geographical regions. The presence of an additional peak between 294-296 nm wavelengths suggests the presence of gadusol and/or deoxygadusol, which are photoprotective compounds, thought to be the precursors of MAAs. Thus, UV protecting compounds in the mucus of fish may not be as conserved between different regions as previously assumed. Our knowledge concerning the effect of UV radiation has advanced considerably in the past decade and my research findings contribute to the better understanding of protective mechanisms of marine fish. The correlations I have found between UV attenuation/exposure, depth, and longitude of sampled individuals lead me to believe that mucus UV absorbing MAA compounds are a highly efficient adaptive defence.

The ecological significance of dissolved organic nitrogen from wastewater treatment plant effluents

Bowyer, Jocelyn Cathryn — 2007-08-24T00:00:00Z

The Ecological significance of subtropical mangrove habitats to juvenile fish

Laegdsgaard, Pia — 2012-11-23T11:39:22Z

The ecology and conservation biology of the yellow-footed rock-wallaby

Sharp, Andy — 2007-08-24T00:00:00Z

The ecology and management of lesser mealworm Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) in eastern Australian broiler houses

Trevor Lambkin — 2011-08-02T00:00:00Z

In Australia, the lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), is a common insect pest of earth floor broiler houses, where it often occurs in large numbers in the bedding material or litter that is used on the floors. Lesser mealworms are reservoirs for several avian pathogens, parasites and food borne diseases. In addition, larvae damage broiler house structures by actively tunnelling into insulation and earth floors. Despite being a common and ubiquitous broiler house pest in Australia, until now, little was known of its ecology in earth floor broiler houses or its susceptibility to registered broiler house insecticides. To determine the factors that influence their localised abundance and distribution in litter, populations of lesser mealworm in several earth-floor broiler houses in sub-tropical Queensland were intensively sampled, experiments were undertaken and life tables constructed. Lesser mealworm larvae were the predominant stage recorded in all litter samples. Life table parameters used stage durations based on a mean broiler house temperature of 31.3°C. Within the broiler houses, substantial horizontal movement of larvae in litter to under feed pans was recorded and this behaviour was supported by life table analyses, which showed atypical lesser mealworm survivorship, suggesting movement by all larval ages. This movement results in large and significant aggregations of larvae under feed pans and along house edges, where chicken access is restricted. Significantly lower larval densities occurred in open locations and under drinker cups, where chickens had complete access. Small larvae appeared to aggregate predominately at the beginning of the flock but continued to move during most of the flock time. In addition, the experimental manipulations in open areas of the broiler house showed that lesser mealworms substantially increased in number inside caged areas without feed pans and under uncaged empty feed pans. Lesser mealworms under similar empty feed pans but enclosed with metal barriers did not increase in the same manner; these barriers significantly restricted their movement. Aggregated populations of lesser mealworms were found to be localised and independent of chicken-feed, manure, and the normally high adult beetle numbers that occur under permanent existing feed pans. Total broiler bird weight in the brooder section during the flock time was considered a driving factor for larval movement, and together with relatively high litter temperatures, a potential source of mortality across larval stages. At almost all types of locations within a broiler house, including experimental treatment locations, numbers of lesser mealworms typically increased over the first 14 d of the flock time, especially in more protected areas such as under feed pans and along house edges, peaked at ≈26 d, and then declined over the remainder of the flock time. In these protected areas or refuges, larvae peaked in numbers, and then left the litter environment to pupate in the earth floor prior to the end of the flock time. This behaviour seemed unrelated to density as the same temporal pattern of abundance was observed under pans within metal barriers, where much fewer insects occurred. It was not observed in uncaged open areas where chickens had complete access. As larvae move away from chickens to refuges, it is likely that populations fail to establish in open areas, but fluctuate in numbers and suffer high rates of mortality. Therefore a typical life stage profile in earth floor broiler houses consists of beetles that emerge from the earth floor at the start of each flock time, lay large numbers of eggs that produce larvae that peak in numbers at ≈21 d, and after a further 21-28 d leave the litter and pupate in the earth floor. These pupae produce adult beetles that begin to emerge prior to the end of the flock time. Removing and replacing litter in the brooder section at the completion of a flock time appeared to inhibit rises in numbers of lesser mealworms over the subsequent flock in the brooder section. In contrast, reusing litter in the grow-out section caused an increase in lesser mealworm numbers in the grow-out over the subsequent flock time. Areas under feed pans and along house edges accounted for 5% of the total house area, but approximately half the estimated total number of lesser mealworms in the broiler house occurred in these locations. Because a high proportion of larvae move to under pan locations and aggregate, this behaviour could be exploited to better manage lesser mealworms by targeting applications of residual control agents at the commencement of the flock to areas under feed pans, which could maximize the efficiency of these agents, and in doing so, reduce the overall quantity of insecticide required to treat a broiler house. The most common practice used for management of lesser mealworm is the treatment of broiler house floors or bedding with insecticides. In Australia fenitrothion, cyfluthrin and spinosad are currently registered for broiler house application, and another insecticide, γ-cyhalothrin, is under consideration. Overall, the most commonly used insecticide throughout eastern Australia is the pyrethroid, cyfluthrin. Because of control failures using this chemical, resistance to cyfluthrin was suspected in Australian broiler farm populations of lesser mealworm. Consequently the responses of several field populations of beetles collected from broiler farms in different Australian states and an insecticide-susceptible reference population to cyfluthrin, spinosad and γ-cyhalothrin were measured in topical application bioassays. In addition, the susceptibility of six Australian broiler house beetle populations and the insecticide susceptible population to several pyrethroids (cyfluthrin, β-cyfluthrin, γ-cyhalothrin & deltamethrin) was measured to determine patterns of cross resistance. The importance of metabolic mechanisms of resistance in these field populations was investigated using similar assays and the synergist piperonyl butoxide. Beetle populations from eastern Australia were first tested with cyfluthrin and resistance (resistance ratios of up to 22-fold at the LC50) was found in almost all of them; with the degree of resistance in a given population directly proportional to the number of cyfluthrin applications it had received. Dose-mortality data showed that 0.0007% cyfluthrin (the LC99.9 of the susceptible population) could be used as a convenient discriminating dose to identify resistant populations. In addition, comparisons of cyfluthrin LC50 values of three broiler populations and a susceptible population, collected and then assayed over a four year interval, indicated that values from all three broiler populations had increased over this time. For spinosad, comparisons of dose-response curves showed that all populations, including the insecticide-susceptible population, were equivalent in their response to spinosad, indicating no pre-existing spinosad resistance. Two of these field populations, including a resistant reference population, had confirmed cyfluthrin/fenitrothion-resistance, but showed no cross-resistance to spinosad. A discriminating concentration of 3% spinosad (just above the highest recorded LC99.9 value of 2.45%) was set to separate resistant and susceptible individuals. For γ-cyhalothrin, baseline studies of beetle populations from most Australian states indicated that it was roughly twice as toxic as cyfluthrin, with a discriminating concentration of 0.005% γ-cyhalothrin chosen to detect any future changes in susceptibility. These same beetle populations were tested with the cyfluthrin discriminating dose to identify possible cross-resistance. Across all populations, there was a significant linear relationship between the γ-cyhalothrin LC50 value and mortality induced by the cyfluthrin discriminating dose. In addition, repeat testing and regression analysis of specific beetle populations to γ-cyhalothrin showed that topical application was a very reliable and repeatable testing method. The γ-cyhalothrin study suggested that cyfluthrin can confer cross-resistance to γ-cyhalothrin in A. diaperinus, but the magnitude of this resistance is not predictable. The susceptibility of beetle populations to four pyrethroids with and without piperonyl butoxide showed that almost all populations, when compared to the reference susceptible population, demonstrated very low susceptibility to cyfluthrin, with some reduced susceptibility to β-cyfluthrin, deltamethrin and γ-cyhalothrin; cross-resistance patterns varied considerably between populations. Adding piperonyl butoxide had no effect on the susceptibility of the susceptible population to any of the insecticides, but it consistently increased the susceptibility of each of the five cyfluthrin-resistant populations to cyfluthrin, β-cyfluthrin and γ-cyhalothrin. The addition of piperonyl butoxide to deltamethrin had inconsistent effects on susceptibility. In general, adding piperonyl butoxide to the four pyrethroids did not completely restore susceptibility to these compounds in resistant populations, indicating the presence of other resistance mechanisms in addition to microsomal-monooxygenase and esterase based metabolic resistance mechanisms. The relative importance of these metabolic resistance mechanisms in each beetle population varied widely between pyrethroids, and the future addition of piperonyl butoxide to these pyrethroids might not necessarily improve their efficacy in the field. Following the laboratory toxicity testing of cyfluthrin and spinosad, field efficacy assessments of these two insecticides and diatomaceous earth, were made on two farms in south eastern Queensland. Diatomaceous earth is known to have insecticidal properties so it was chosen to assess its potential as a natural litter treatment on one farm. Insecticide treatments were applied mostly to earth or hard cement floors in the trial broiler houses, before placements of new bedding. Efficacy of each agent was assessed by regular litter sampling over time. The lowest numbers of lesser mealworm were generally recorded in houses with hard floors, with the most effective treatment being a strategic application of spinosad to hard floors in 1 m bands under feed supply lines. In earth floor broiler houses two under-feed-line treatments (2 m wide, 0.18 gai in 100ml water/m2, & 1 m wide, 0.11 gai in 33 ml water/m2), and an entire floor treatment with 0.07 gai in 86 ml water/m2 gave significantly better control than cyfluthrin and no treatment. The effectiveness of spinosad relied on dose and volume of water used to apply the chemical. Spinosad was ineffective when applied to the surface of bedding in larger volumes of water. The 1 m wide band under-feed-line treatment was the most cost-effective spinosad treatment, using less than half the active component per broiler house when compared to the other equally effective spinosad treatments. All label rate cyfluthrin treatments, and applications of diatomaceous earth applied singly and with spinosad were ineffective. The results of this field assessment hold promise for spinosad as a broiler house treatment, but results for diatomaceous earth and cyfluthrin applications in these trials indicate that they were largely ineffective. Field and laboratory studies indicated that individuals of several broiler house populations of A. diaperinus with reduced susceptibility to cyfluthrin and fenitrothion showed a marked increase in susceptibility to cyfluthrin (up to 14.3-fold), γ-cyhalothrin (up to 51.5-fold) and fenitrothion (up to 2.7-fold), following treatments of spinosad made to the earth floors of broiler houses. This trend was not observed in two insecticide-susceptible broiler house populations from northern Queensland similarly tested with spinosad, but showed susceptibility to the insecticides in these two populations to be stable over the time of the study. In addition, this phenomenon was not observed in beetle populations from similar broiler houses that had received no spinosad treatments but had sustained treatments of cyfluthrin, or no treatments. Directly following cessation of spinosad treatments in broiler houses, cyfluthrin and γ-cyhalothrin susceptibility in beetle populations collected from these houses returned to levels similar to those recorded prior to commencement of spinosad treatments. The marked increase in susceptibility to pyrethroids after exposure to spinosad was also induced in the laboratory where an initial sub-lethal dose of spinosad made to adults of a cyfluthrin/fenitrothion resistant lesser mealworm population enhanced the effect of the subsequent γ-cyhalothrin application. Overall, the results indicated that exposure of A. diaperinus, either as larvae or adults to spinosad on earth floors of broiler houses, predisposes individuals to greater susceptibility to subsequent pyrethroid and possibly other insecticide treatments. The field results showed that this predisposition to susceptibility was not directly transferred genetically to following generations as the population on the Beerwah farm, after cessation of spinosad, produced a generation that returned immediately to low levels of susceptibility to cyfluthrin and γ-cyhalothrin similar to those recorded at the start of the study. The mechanism of these increases in insecticide susceptibility following exposure to spinosad was not determined but the interaction, which only occurred in cyfluthrin/fenitrothion resistant individuals, suggested that mechanisms responsible for resistance were compromised in some way, inferring the possibility of deactivation of resistance mechanisms by spinosad; these mechanisms are most likely associated with enzymes and subsequent insecticide resistance. This phenomenon is an ideal addition to the management of A. diaperinus in broiler houses in that coordinated and sequenced applications of spinosad followed by effective pyrethroid treatments would do much to improve the efficacy of control agents, perhaps reduce concentrations of insecticides applied to broiler houses and mitigate further developments of pyrethroid resistance. A future regime for application of control agents for management of lesser mealworm in Australia is to treat broiler house floors with spinosad in metre wide bands under feed supply lines and in half metre strips along side walls at a dose of 0.11 gai/33 ml water/m2 for four consecutive flocks; followed, immediately after the placement of bedding, by treating the entire surface of bedding with γ-cyhalothrin at 0.03 gai/100 ml water/m2. This regime could be repeated for three consecutive flocks starting in spring and continuing through to autumn. If γ-cyhalothrin is not registered in Australia for broiler house application in the near future, other insecticides could be trialled as an alternative to γ-cyhalothrin but laboratory and field evaluation of alternative insecticides would be required prior to incorporating them into a management sequence. Effectiveness of treatment regimes could be evaluated by assessing numbers of lesser mealworms under three feed pans in the central area of the brooder section four weeks into a flock cycle by quickly moving feed pans sideways and visually assessing the presence of larvae. If no larvae are immediately observed, this could be used to roughly assess treatment effects, and if effective, insecticide applications could be reduced or ceased for one or two flocks. When larvae are again observed this way under feed pans, the control regime can be resumed. The frequent use of cyfluthrin in broiler houses in eastern Australia has selected for cyfluthrin resistance and led to reduced susceptibility to γ-cyhalothrin. Continued use of cyfluthrin for the control of A. diaperinus, at least in eastern Australia, should be seriously questioned. Considering the levels of spinosad resistance that have been recorded in other insect pests, the potential cross-resistance issues with γ-cyhalothrin, and the fact that piperonyl butoxide will not reliably synergise pyrethroids to mitigate insecticide resistance in resistant beetle populations, sustained future usefulness of these chemicals as broiler house treatments for beetle management will rely on combining their applications effectively and prudently. For the future, the most obvious next step for lesser mealworm research is to assess in the field the efficacy of this proposed targeted treatment regime, in particular the effectiveness of encapsulated cypermethrin and dinotefuran. Field trialling of these regimes, incorporating direct litter sampling and evaluations of insect numbers in litter samples is the most accurate means of assessing the effectiveness of this proposed pest management procedure. In addition to sampling litter during the trial to measure effectiveness of the treatments, it would be prudent to progressively monitor the susceptibility of the broiler house beetle populations to both chemicals in order to monitor for possible changes in insecticide resistance as a result of this treatment regime.

The ecology and population genetics of the prickly forest skink in a fragmented habitat

Sumner, Joanna Mary. — 2007-08-24T00:00:00Z

The Ecology, Management and Monitoring of Wildlife Populations in Fragmented Landscapes - a Koala Case Study

Rhodes, Jonathan Roger — 2008-11-21T00:00:00Z

Habitat destruction and degradation are the most important threatening processes for the majority of species of conservation concern. As landscapes become more fragmented their spatial structure becomes increasingly important for the viability of wildlife populations. Therefore, understanding the dynamics of how populations interact with landscape structure is crucial for developing effective wildlife management and monitoring strategies. To achieve robust management, such an understanding should be incorporated into decision theory approaches for the design of management and monitoring strategies. Monitoring is a crucial component for assessing the outcome of management, because this can then be used to inform future management actions in an adaptive management framework. However, for many species, their spatial population dynamics are not well understood and objective management frameworks not well developed. In this thesis I use modelling approaches to develop the components of an adaptive management framework for species of conservation concern that occur in fragmented landscapes. I use the koala (Phascolarctos cinereus) as a study organism and specifically address three key components that are important for adaptive management. These components are: (1) the development of novel approaches for modelling and understanding spatial population processes, (2) the application of modelling approaches to develop general principles and methods for managing wildlife populations in fragmented landscapes and (3) the application of modelling approaches to identify the best spatio-temporal sampling strategies for monitoring population trends in fragmented landscapes. This research advances our understanding of the dynamics of wildlife populations in fragmented landscapes, but importantly also develops tools and general principles for the adaptive management of these populations. To improve our understanding of the dynamics of populations in fragmented landscapes I develop several novel modelling approaches. Firstly, I develop an approach for disassociating the effect of natural habitat and anthropogenic influences on population distributions using static occupancy models. This approach allows inferences to be made about how important the distribution of habitat is compared to other human-related factors. Secondly, I develop modelling approaches for understanding habitat selection and dispersal processes. In particular, I address common problems for modelling complex habitat selection processes and parameterising dispersal simulation models. The habitat selection models are novel because they account for habitat preferences that depend upon the spatial location of habitat. The novel emphasis for the dispersal models, is showing that pattern-oriented approaches are useful for parameterising dispersal simulation models, even when we have little data. These models make an important contribution to our understanding of and methods for understanding spatial population processes. These and other modelling approaches are then applied to some key management questions, in order to develop general principles and methods for wildlife management decision-making. These studies relate to identifying the best spatial allocation of different management strategies, the planning of road networks to minimise impacts on wildlife and the impact of different mortality rates on the ranking of habitat protection strategies. First, I show that the relative spatial distribution of habitat and anthropogenic influences has important implications for the spatial allocation of management strategies. Second, I show that increasing traffic volume on existing roads is generally preferential to building new roads in terms of minimising the impact on wildlife mortality. Third, I use a multi-criteria decision analysis to show that the spatial arrangement of protected habitat is much less important for populations subject to high mortality rates than those subject to low mortality rates. Finally, spatially-explicit modelling approaches are applied to questions related to how sampling effort should best be allocated spatially and spatio-temporally to monitor population trends. These studies reveal that the best sampling strategy depends predictably upon the monitoring objectives and the dynamics of the species. Using the principles developed, improved monitoring strategies and ultimately improved management strategies will be possible. This thesis makes an important contribution to the development of adaptive management strategies for wildlife populations in fragmented landscapes. To implement an adaptive management approach, the modelling, management and monitoring components must be explicitly linked. By developing each of these components, this thesis provides a strong basis from which an adaptive management framework can be constructed. How this may be achieved and key areas for future research are discussed.

The Ecology of Cycads: Living Representatives of an Ancient Plant Lineage and their Interactions with Animals.

John Hall — 2011-08-22T00:00:00Z

Abstract Cycads are charismatic plants occupying a special place in botany because of their ancient fossil record, extending back over 250 million years. Cycads have evolved remarkable interactions with animals, including insect pollination, vertebrate seed dispersal, and defences against herbivory. In this thesis, I explore the nature of such cycad-animal interactions in contemporary ecosystems, and how we can incorporate such information into our understanding of ancient plant ecology. I argue that the biotic interactions of cycads, evolved in antiquity, have been central to their survival, allowing them to persist as “gymnosperms in a sea of angiosperms”. All cycads thus far studied exhibit host-specific obligate mutualisms in their pollination (usually by beetles). Exclusion tests on the Australian cycad Cycas ophiolitica (chapter two) demonstrate the plant can be pollinated by beetles inhabiting the reproductive structures (pollination vector for Cycas was unknown at the study's outset). Airborne pollen loads collected at distances from coning C. ophiolitica plants suggest secondary pollination by wind is possible, but only at high density of coning plants. The overall morphology and coning behaviour of C. ophiolitica suggests maladaption for wind pollination. A study of pollen aerodynamics (chapter 3) found that when dropped en mass, pollen from cycads and other animal pollinated plants settled quickly in large aggregations, whereas pollen from wind pollinated plants fell slowly as single grains. Cycads from oceanic islands, dispersed by floating seeds, were hypothesised to be wind pollinated because of isolation from specific insect pollinators. However the aerodynamics of their pollen (dimensions, settling velocity and aggregation tendency) are shown to be similar to those of cycads known to be insect pollinated, suggesting no selection for wind pollination. Cycads have repeatedly been “invaded” by “new” host specific pollinators over the course of their history. For example, the beetles identified as pollinators of Australian Cycas (this study) have no taxonomic affinity with those pollinating C. revoluta in Japan (identified by other authors). Hence, cycad reproductive structures seem to be pre-adapted for the attraction and incorporation of new pollinators, making the cycad pollination symbiosis robust over evolutionary time. Contemporary cycads have large fruit-enclosed seeds, dispersed by small mammals, with such dispersal being limited to short distances. Seed dispersal distances for the Australian cycad Macrozamia miquelii (chapter four) were restricted to less than 5m, with 70 - 100% of propagules remaining within 1 metre of maternal females. Macrozamia miquelii occurs in high density stands of up to 5,000 plants per hectare. Brushtail possums (Trichosurus vulpecula), the only dispersal fauna observed, ate the fruit and discarded the seed in situ beneath parent plants. Both cycad seeds and foliage contain unique compounds highly toxic to animals. The seeds of M. miquelii and C. ophiolitica (chapter 5) contain high concentrations of the known toxin cycasin (0.34 and 0.28% of fresh weight respectively). This study demonstrated for the first time that toxic cycasin is absent from the fruit. Also, the fruit mass is as heavy as the seed itself, and becomes brightly coloured during the dispersal phase. Cycads thus seem adapted for dispersal by large animals capable of swallowing propagules whole, digesting the fruit and voiding the toxic seeds intact. Extant ratites fit this profile, as does Pleistocene megafauna present in Australian cycad habitats 40,000 years ago. The 285 extant cycad species are slow-growing, dioecious understory plants. Although numerically insignificant globally, cycads can dominate understories locally as high density populations. As a consequence of the dispersal of large, heavy propagules en mass by megafauna, I argue that cycads have always existed as spatially isolated, high density stands or “colonies” within landscapes. Individuals are well adapted to establish in such stands, where they are advantaged by access to mates and host specific pollinators through participation in synchronised reproductive events. Physical defences such as leaf toughness and spinescence are typical of cycads globally (chapter 6). It is shown that cycad leaf toughness usually exceeds that of conifers and sclerophyll angiosperms. Cycads offer a counterpoint to angiosperm ecology. Their long-lived, slow-growing, well-defended foliage is relevant to explanations of angiosperm dominance and simultaneous gymnosperm persistence. In sum, the diversity and sophistication of cycad-animal interactions defy the traditional perception of these plants as primitive "living fossils". Cycads have been interpreted as relicts comparable to ecologically restricted lineages such as Ginkgo. I argue that cycads are more comparable to conifers, in that both groups are gymnosperms that continue to occupy notable habitat in the post-Cretaceous angiosperm-dominated flora. But unlike wind pollinated and dispersed conifers, it is the biotic interactions of cycads that have been central to cycad persistence over 250 million years. These include a robust insect pollination mutualism, vertebrate seed dispersal adaptations that maintain and propagate high density stands, and defensive adaptations that allow cycads to outlive other understory plants. Biogeographical evidence plausibly extends these interactions back to Mesozoic times. Cycads have not survived by chance.

The Ecology of Dispersal: Causes and Consequences of Phenotype-dependent dispersal

Scott Burgess — 2011-06-21T00:00:00Z

Dispersal is one of the few traits shared by all organisms. The study of dispersal has a long history in both ecology and evolutionary biology. Ecologists have long sought to understand how dispersal affects population dynamics and species coexistence, while evolutionary ecologists have sought to understand the evolution of dispersal despite significant costs to the individual. Remarkably, these two discussions have rarely informed each other — in particular, ecologists often ignore the role that dispersal costs may play in influencing population-level processes. This thesis seeks to unify these two sub-disciplines of dispersal biology by investigating how among- individual variation in phenotype (e.g., dispersal duration and larval size) influences dispersal behaviour, habitat selection, post-settlement performance, and ultimately population dynamics. I used marine bryozoans (Bugula neritina and Watersipora arcuata) as an experimental system and combined the results from laboratory and field studies with theoretical models. In chapter 2, I asked whether the population effects of phenotypic variation among individuals match or exceed the influence of spatial and temporal variation in the number of individuals. To do this, I simultaneously manipulated the phenotype (dispersal duration) and the density of colonizers and measured subsequent population structure. I found that the phenotype and abundance of individuals colonizing a patch strongly interacted to affect subsequent reproductive output of the population. In fact, populations founded by a few individuals with short dispersal durations (i.e., in relatively good ‘condition’) actually had a similar reproductive yield to populations founded by many individuals with long dispersal durations (in relatively poor ‘condition’). In chapter 3, I conducted a series of experiments in the field and the lab to estimate the relative importance of direct and indirect deferred costs of dispersal. I then used those data to parameterise a theoretical model to describe how dispersal costs interact with the spacing and quality of habitat to influence population connectivity. I found that the deferred costs of dispersal can result in the strength of connectivity to distant good quality patches being the same as that to nearby poor quality patches. Costs of dispersal therefore have a number of implications for understanding the spread of invasive species and developing spatial conservation plans. In chapter 4, I showed that dispersal duration and larval size affect larval behaviour prior to settlement, and these effects are likely to interact with the more well studied external settlement cues. I also present a habitat selection model, parameterized with the experimental results, to explore when these phenotype-dependent behaviours might be adaptive under different scenarios of habitat abundance and quality. I suggest that presettlement larval behaviour can be viewed in the context of informed dispersal where individuals use internal and external cues to assess the current settlement habitat in relation to unknown habitat elsewhere. In chapter 5, I used an experimental approach that examined the effects of maternal exposure to temperature on the phenotype and performance of offspring in different temperatures. I also analysed autocorrelation in water temperature from field measurements to estimate intergenerational predictability in environmental correlations. I found that the responses of larvae to different water temperatures depended on the temperature that their mothers experienced. Analysis of time series data on temperature in the field indicated that offspring are likely to experience similar thermal environments as their mothers, particularly during the larval and very early post- metamorphic life-history stages. In this paper, I provide estimates of absolute and relative maternal fitness and discuss how the benefits of transgenerational plasticity depend on the importance of frequency- (or density-) dependent selection. The need to understand dispersal and colonization processes has become increasingly apparent in the context of managing threatened or invasive species, as well as predicting biological responses to environmental change. The main implications of the results presented in this thesis are that costs of dispersal, phenotypic variation, and phenotypic links between life-history stages at the individual level can have consequences at a population level: consequences that would not be predicted assuming dispersers were homogeneous. Studying the costs of dispersal, and the role of phenotypic links among life-history stages, is therefore fundamental for a mechanistic understanding of population processes. It is hoped that this work will contribute to the broader understanding of the links between ecological and evolutionary dynamics that are essential to properly manage biodiversity.

The ecology of fish larvae in Pumicestone Passage : an estuarine system in Southeast Queensland, Australia

Pham, Cong Tri. — 2007-08-24T00:00:00Z

The ecology of individual specimens Acanthaster planci in low density populations

Souter, David William — 2008-11-21T00:00:00Z

This is the first long-term study of A. planci based on repeated observations of recaptured specimens living in three low density populations at Lady Musgrave Island Reef, Heron Island Reef and One Tree Island Reef, situated in the southern Great Barrier Reef. This study describes the growth of adult specimens, their dietary preferences, their feeding rates and their movements over periods ranging from days to more than three years. These data enable the ecology and life history strategy of A. planci in low density populations to be examined in detail for the first time. In addition, the results of this study enable a true comparison of the behaviour of individuals in low density populations with those maintained in the laboratory or comprising outbreaking populations in order to assess the applicability of previously held hypotheses, notions and beliefs concerning this starfish. The mean density of starfish at each reef ranged between 93.7 starfish·km-2 at Heron Island Reef and 535.7 starfish·km-2 at Lady Musgrave Island Reef and was well below that ascribed to outbreaking populations. Each population exhibited adult-dominated, uni-modal size frequency distributions with starfish ranging in size from 27 cm to 59 cm in total diameter. The mean size of starfish sampled within each population did not change significantly over the duration of the study and was 41.9 cm, 44.5 cm and 50.9 cm at Heron Island, One Tree Island and Lady Musgrave Island Reefs respectively. These results indicate that both adult mortality and recruitment within low density populations was low and/or unpredictable. The growth of 59 starfish ranging in size from 28 cm to 59 cm in total diameter and recaptured between 1 and 5 times, was recorded over periods ranging between 65 and 1252 days. The growth of these individuals was extremely plastic with the rates of change in size between encounters ranging between 9.2 mm·month-1 and 18.4 mm·month-1 demonstrating that, in the field, A. planci normally exhibit periods of significant growth and shrinkage, which are interspersed with periods of stasis. Several starfish maintained rapid growth beyond 45 cm in total diameter and many demonstrated that specimens of A. planci have the capacity to grow significantly throughout their entire size range. Although the rate of growth tends to decline with increasing size, many of these starfish maintained large sizes for the duration of the study. This study showed that in habitats where food is not limiting, specimens of A. planci exhibit plastic asymptotic growth where the maximum size of a starfish is likely to be constrained by morphometry and physiological demands, but sub-maximal asymptotes can be temporarily imposed by the various environmental conditions experienced throughout the life of an individual starfish, particularly food availability. The achievement of large body sizes increases fecundity and confers greater resilience to predation and to periods of food limitation. Phenotypically plastic growth enhances the survival and fitness of individuals by allowing them to accommodate changes in environmental conditions throughout their lives. The mean coral consumption of each of 14 recaptured starfish at Lady Musgrave Island Reef ranged between 0 cm2·day-1 and 974 cm2·day-1, while at One Tree Island Reef the feeding rates of 20 starfish ranged between 4 cm2·day-1and 570 cm2·day-1. The majority of individuals did not show significant changes in their feeding rates between encounters or between seasons, although the great variation in the amounts of coral eaten by these starfish each day might have obscured any clear seasonal changes in the feeding rates of these starfish. At Lady Musgrave Island Reef, significant variation in the feeding rates of different individuals was recorded during 2 of 4 field trips and also within both summer and winter. Some of this variation can be attributed to the fact that larger starfish generally consumed more coral than smaller starfish at both reefs. The remaining variation was attributed to differences in the composition of the coral community within the specific habitats occupied by different starfish. Starfish occupying habitats in which preferred corals were abundant generally consumed a smaller area of coral per day suggesting that the return per unit effort foraging on preferred corals is greater, thus increasing the survival and fitness of individuals by reducing the time spent foraging and exposed to predators. The dietary preferences of 43 individuals were investigated. The diets of 10 of these starfish were recorded on multiple occasions. Twenty-four genera of scleractinian coral were recorded in the diet of these starfish. When eaten, Acropora and Seriatopora were universally preferred, while Stylophora was usually preferred and Porites was generally not preferred. Although regularly preyed upon, Montipora was often consumed in similar proportions to its availability. Pocillopora was more acceptable to individuals at One Tree Island Reef than at Lady Musgrave Island Reef and not preferred by any starfish investigated at Heron Island Reef. The dietary preferences of those starfish observed repeatedly did not change significantly between field trips or seasons. Significant variation in preferences between individuals examined during the same trip was uncommon at Lady Musgrave Island Reef and Heron Island Reef but occurred during each field trip conducted at One Tree Island Reef. These results indicate that A. planci does exhibit a hierarchy of preferences for various corals but the stability of this hierarchy is moderated by the dietary experience of the individual and the availability of preferred coral genera, such that when preferred corals, particularly Acropora, are abundant, there is little variation in preferences between individuals or within individuals over time. As the abundance of preferred corals declines, starfish consume a broader range of corals. The foraging behaviour of A. planci is consistent with a time minimising strategy and appears to conform to the predictions of optimal foraging theory. The mean daily displacement of individuals sampled ranged between 0 m·day-1 and 6.8 m·day-1 at Lady Musgrave Island Reef and between 0.2 m·day-1 and 4 m·day-1 at One Tree Island Reef. At both reefs, most starfish did not exhibit significant variation in their daily displacements between field trips or between seasons, but the daily displacements of different individuals varied significantly within 6 of the 7 field trips conducted, and also within summer and winter. Individuals occupying habitats with greater cover of live hard coral tended to exhibit smaller daily displacements. Homing to a refuge was common among starfish at Lady Musgrave Island Reef but rare in starfish at One Tree Island Reef. No relationship between starfish size and daily displacement or homing frequency was found at either reef. The mean daily displacement of the population sampled at Lady Musgrave Island Reef was significantly greater during summer than during winter, but such seasonal variation was not apparent within the population at One Tree Island Reef. The mean daily displacement of all starfish sampled at One Tree Island Reef was significantly greater than those sampled at Lady Musgrave Island Reef. The daily movements of A. planci in populations of low density are highly plastic and appear to be influenced by the abundance of preferred corals providing food, predation pressure and the cover of live hard coral providing suitable refuges. Over periods ranging between 140 days and 1249 days, individual starfish were relatively stationary. The mean rate of displacement between encounters for 41 starfish recaptured at Lady Musgrave Island Reef was 70.6 m·year-1 and was 43.9 m·year-1 for the 8 starfish recaptured at One Tree Island Reef. At Lady Musgrave Island Reef, almost 30% of recaptures occurred within 10 m of an individuals last recorded position and overall, greater than 85% of all recaptures occurred within 100 m. The furthest any starfish moved from its point of initial capture was 330 m in 734 days. Starfish that had traversed sandy habitats exhibited greater changes in displacement compared with those that had travelled across coral. Starfish located on reef slopes tended to navigate directional paths, which prevented retracing ground already covered, while the direction of movement of starfish located on reticulated or isolated patch reefs was more random. These results show that specimens of A. planci in populations of low density do not undergo long migrations and could potentially live their entire life within a small area of reef. A. planci demonstrate plastic phenotypic responses in growth and foraging behaviour to varying environmental conditions experienced throughout their life. These characteristics have evolved to counteract unpredictable recruitment while living in low densities by promoting survival and longevity of individual starfish. This allows A. planci to adopt an iteroparous strategy which enhances the fitness of individuals by enabling them adapt the level of reproductive effort to prevailing environmental conditions. Because the life history strategy of A. planci has evolved to ensure survival and longevity of individual starfish, the appearance and persistence of outbreaks is an inevitable consequence of circumstances that facilitate greater than usual fertilisation success. Identifying the mechanisms that might produce unnaturally high fertilisation success will be important in determining the causes of primary outbreaks.

The ecology of soft sediment tidepool dwelling gobies (Pisces: Gobiidae) in Moreton Bay, Australia

Craig Chargulaf — 2011-04-29T00:00:00Z

Tide pools are challenging environments. They can experience rapid changes in temperature, salinity and pH yet are occupied by fishes and other organisms. While more attention has been given to community composition, zonation and competition of intertidal rockpool faunas, soft sediment tidepools are potentially important in terms of biodiversity and fisheries. Gobies, dominate the communities of both rock- and soft sediment pools by virtue of physiological and behavioural adaptations. In part their great diversity is potentially a function of the ability to cope with great adversity. The combination of physiological challenges and low resource diversity offers and useful natural laboratory for examining resource partitioning and speciation processes in extreme environments. Moreton Bay, Australia contains extensive areas of soft sediment shores on which pools commonly occur. The objectives of this thesis were to: 1) quantify the use of soft sediment tidepools by fishes and their associated meiofaunal prey, and 2) examine more closely how several gobiid species are able to coexist in such a homogenous environment. A twelve month survey of fishes in soft sediment tidepools was undertaken between January and December 2009 at three sites: Dunwich, Manly and Godwin Beach, in south-east Queensland, Australia. The gobies Favonigobius lentiginosus, Favonigobius exquisitus, Pseudogobius sp., whiting Sillago spp. and the blenny Omobranchus punctatus were the most abundant species. The mean density of fish was between 0.29 ± 0.13 and 5.04 ± 1.74 fish L-1. Abundance of fish was positively correlated with pool volume. Most fish caught were juveniles, suggesting that soft sediment pools act as nurseries for some species. To assess prey availability and therefore the potential role of soft sediment pools as foraging areas during low tide, I assayed the meiofaunal occupation of soft sediment tidepools at each of the three intertidal shores. Mean maximum meiofaunal abundances were found at Godwin Beach (1389.2 ± 158.2 individuals per 20 cm3) and abundances differed significantly among months. Nematodes and copepods were the most abundant taxa while all other taxa contributed to <10% of the total abundances. Unlike fish abundances, pool volume did not correlate with the abundance of meiofauna and only at Dunwich did depth (p < 0.0001) and surface area (p < 0.01) have a positive correlation. The soft sediment pools found around Moreton Bay provide sufficient meiofaunal prey resources for juvenile and small fish that use them. The feeding ecology of two sympatric gobies, Favonigobius lentiginosus and F. exquisitus was investigated for tropic partitioning of resources. Gut contents were analysed to explore competition and temporal dietary shifts. Copepods dominated goby diets and there was no evidence of temporal partitioning between the congeners, even when sympatric. Food resource competition did not appear to be a limiting factor between F. lentiginosus and F. exquisitus despite cohabitation in such restricted environments, providing tentative support for the unified neutral theory hypothesis. Using scanning electron microscopy (SEM) character states for phylogenetic analysis were developed from images of the oral and pharyngeal jaws of six soft sediment tidepool dwelling gobies. The aim was to test if resource partitioning could be identified at a morphological level through divergence in pharyngeal and oral jaws. The genera Arenigobius, Acentrogobius and Favonigobius differed little morphologically, from which I infer that trophic resource competition is not a primary structuring agent in the evolution of gobies in such intertidal pools. Competition for food resources while the tide is in, partitioning of non-food resources, or spatial segregation by virtue of different physiological tolerances are suggested as mechanisms that might act to support the coexistence of such trophic isomorphs. Tank experiments were conducted assess whether Favonigobius lentiginosus, which typically occupies soft sediment tidepools, and Arenigobius frenatus, typically found in nearby subtidal seagrass beds, actually prefer those habitats. Both A. frenatus and F. lentiginosus preferred the seagrass habitat when alone. When in the same tank, F. lentiginosus significantly altered its preferred habitat towards sand (p < 0.01). Higher densities of F. lentiginosus also caused individuals to use more of the marginal habitats. I suggest that the use of soft sediment tidepools by F. lentiginosus may be a consequence of competition with A. frenatus for space in seagrass beds. Soft sediment tidepools are dynamic ecosystems that contain a small but potentially important group of fishes dominated by juveniles that mainly these pools as nursery refuges and, by virtue of pool dwelling meiofaunal communities, foraging areas during low tide. The intertidal gobies of Moreton Bay appear to be competing directly for prey, as most lack any apparent morphological or behavioural specializations that might allow them to segregate resources.

The economic impact of Noosa national park : an holistic assessment

Pearson, Leonie. — 2009-12-09T00:00:00Z

The Economic Potential for Smallholder Rubber Production in Northern Laos

Manivong, Vongpaphane — 2008-11-21T00:00:00Z

Rubber smallholdings are being established by shifting cultivators in Northern Laos, in response to demand from China and encouraged by government land-use policy. This can be seen as part of a general transition from subsistence to commercial agriculture in the uplands in particular, from shifting cultivation to tree crop production. This study examines the economics of smallholder rubber production in an established rubber-growing village in Luangnamtha Province and models the likely expansion of smallholder rubber in the Province. Data were obtained from key informant interviews, group interviews, direct observation, and a farm-household survey. Latex yields were estimated using the Bioeconomic Rubber Agroforestry Support System (BRASS). A discounted cash flow (DCF) model was developed to estimate the net present value for a representative rubber smallholding. This model was then combined with spatial data in a Geographical Information System (GIS) to predict the likely expansion of rubber based on resource quality and accessibility. The study shows that, given current market conditions and credit support, investment in smallholder rubber production in the uplands of Northern Laos can be profitable. The results from the DCF analysis for the study village show that the expansion of rubber planting in that village is based on good economic returns. The spatial analysis indicates that the potential for rubber in the study village is not an isolated case; there are also other areas in Luangnamtha Province that appear to be economically suitable for rubber. Therefore, rubber can be considered as one of the potential alternatives for poor upland farmers, in line with the government policy of stabilising shifting cultivation and supporting new livelihood options for poverty reduction. However, there are risks associated with rubber production and emerging constraints of land and labour, hence government should move cautiously in promoting rubber where farmers are uncertain about reducing their dependence on shifting cultivation. The role for government, as in other countries where smallholder rubber has played a significant role in rural development, is to ensure the provision of good quality planting material, to assist financially during the long investment period when no income is generated, and to invest in roads and marketing infrastructure. In particular, maintaining secure access to the China market will be crucial for the sustainability of smallholder rubber in Northern Laos. If carefully managed, the expansion of smallholder rubber in Laos has the potential to contribute to sustainable rural livelihoods.

THE ECONOMIC ROLE OF FORMAL AND INFORMAL INTER-FIRM NETWORKS IN THE DEVELOPMENT OF SMALL AND MEDIUM INDUSTRIAL ENTERPRISES: STUDY OF SYMBIOSIS IN THE INDONESIAN GARMENT INDUSTRY

Adam, Latif — 2008-11-21T00:00:00Z

It has been frequently argued that the formation of inter-firm networks (business cooperation) could be used as an effective means to promote SMIEs in Indonesia. However, as the majority of previous studies have concentrated largely on investigating SMIEs internal management, there has been only little detailed information available concerning the determinants and the economic role of inter-firm networks in the development of Indonesian SMIEs. This thesis discusses not only issues involving the development of SMIEs from the angle of SMIEs internal management, but also goes further to examine what are the determinants impacting on the efforts of SMIEs to develop and maintain long-term inter-firm networks, and to what extent and how have inter-firm networks contributed to the improvement in their performance. Thus, this thesis is expected to make several distinctive contributions to knowledge since it provides the first examination of the determinants and the economic role of inter-firm networks in the development of SMIEs in the Bandung garment industry, and is the first estimate of technological capabilities, competitiveness, and growth of SMIEs in Indonesia. To provide a better foundation for considering these three issues, this thesis starts by analyzing the development of both the Indonesian SMIEs and the Indonesian garment industry. Subsequently, this thesis constructs a theoretical framework by adopting a pluralistic theoretical approach. The theoretical framework emphasizes the importance of trust and competency as fundamental determinants for cementing the formation and operation of a network. The framework also highlights several advantages that SMIEs can enjoy from their involvement in a particular type of inter-firm networks. Using these initial analyses and the theoretical framework as guidance, a case study is then conducted by surveying 210 SMIEs in the garment industry in several specific locations of Bandung. The analysis outlined in this thesis indicates the important role of SMIEs in the Indonesian economy. SMIEs are able not only to create employment and generate income for both household economies and the national economy, but importantly also to contribute to Indonesias industrial exports. However, despite these important roles, the analysis of the survey (fieldwork) data also indicates that SMIEs suffer from a number of problems. It is found that most SMIEs surveyed face difficulties in securing and expanding their markets. They also have limited resources and access to capital, technology, and raw materials. The majority of SMIEs surveyed eased their problems by engaging in inter-firm networks. However, due to unfair practices, untrustworthy and incompetent partners, a significant number of them terminated and discontinued their engagement. Consistent with theoretical arguments, it is found that by developing inter-firm networks, SMIEs surveyed have an alternative solution to securing and expanding their markets. Furthermore, developing inter-firm networks provides opportunities to SMIEs to have better access to capital, technology, information, and raw materials. This suggests that inter-firm networks can be used as an important means of facilitating the development of SMIEs. Three important conditions may facilitate the preference of the majority of SMIEs surveyed to develop inter-firm networks. Firstly, entrepreneurs in the Bandung garment industry come from a similar socio-cultural background. Furthermore, Bandungs garment products are popular among many Indonesian for their up-to-date design, good quality, and competitive prices. This popularity attracts many enterprises from Bandung and other Indonesian cities to develop networks with Bandungs garment enterprises. In addition, by using a binomial logit model, it is found that several attributes of entrepreneurs, particularly educational background, correlate positively with the decision of SMIEs to develop inter-firm networks. The higher educational level of entrepreneurs, the more likely they are to develop inter-firm networks. The fact that the majority of entrepreneurs interviewed have a high level of educational background could be another reason why inter-firm networks have been adopted as a common strategy by the majority of SMIEs surveyed. This is because educational background correlates positively with the ability to build contacts and to communicate with others. The better entrepreneurs communicate with others, the more capable they are to develop inter-firm networks. In line with the theoretical argument, the analysis of the fieldwork data also indicates that trustworthiness and competency are fundamental determinants for the success of long-term inter-firm networks. Thus, to develop such networks, SMIEs need not only to build trust and competency, but also to find trustworthy and competent partners. This entailed several initial mechanisms being utilized by the SMIEs surveyed. Interestingly, the initial mechanism that SMIEs choose to develop inter-firm networks determines whether or not their networks can survive over a longer period of time. Indeed, as the estimates of the binomial logit model indicates, if entrepreneurs develop cooperation through mechanisms other than trade and industry associations and government programs, this increases the probability of long-term business cooperation. In contrast, if entrepreneurs develop business cooperation via trade and industry associations and government programs, this decreases the probability that cooperation will continue over a longer period of time. By using an ordered probit model, the analyses of the survey data also shows that inter-firm networks, together with several other variables, positively influence the performances of SMIEs surveyed. If SMIEs are involved in inter-firm networks, this increases their probability of improving their technological capabilities, expanding their markets, and accelerating their growth. However, the estimates of the ordered probit model also indicate that each type of inter-firm network brings a different positive impact. Engaging in more than one type of inter-firm network has a larger impact on improving the performances of SMIEs surveyed than involvement in one type of network. Also, entering a vertical inter-firm network (putting out and subcontracting) has a greater positive impact in enabling SMIEs to increase their business performances than entering into horizontal inter-firm network (clustering). The significant role of inter-firm networks in providing various benefits for SMIEs may in turn encourage the government to become involved in the promotion of inter-firm networks. However, by assuming SMIEs that can maintain their inter-firm networks over a longer period of time are those that succeed in developing their networks, it is found that such networks can only be developed successfully if they are based on economic and profit motivations. This suggests that the government should focus and limit its involvement in the promotion of inter-firm networks by only adopting market-oriented policy based on actual needs as articulated by SMIEs themselves. Indeed, as the SMIEs surveyed mention, instead of intervening directly, the government should pay more attention to the creation of conducive and stable legal and commercial (economic) conditions. Many SMIEs believe that such an environment is an important prerequisite not only to stimulate the development of inter-firm networks, but also to ensure that these work effectively. Without having to intervene directly, there are many ways in which the government can support the development of inter-firm networks. The first important one is to design and introduce a legal framework (laws) that can be used to solve commercial disputes of firms in a network. In addition, the government could eliminate various nuisance taxes and reduce tariffs and taxes on high quality imported inputs to enable SMIEs to develop inter-firm networks. Finally, the government should eliminate discriminatory policy against SMIEs and implement anti-monopoly laws to ensure that SMIEs and LIEs compete fairly.

The Economics of Alcohol in Australian Rural Communities

Dennis Petrie — 2010-05-13T00:00:00Z

Alcohol is a complex good which is ingrained within the social fabric of Australian culture. This is even more apparent within rural communities which are considered to have higher levels of risky alcohol consumption. While alcohol provides pleasure to many, it has devastating effects for others. Not only are individuals themselves affected, but also their families and the community at large. This thesis considers a number of the economic aspects associated with alcohol consumption in rural Australia. This thesis was completed in conjunction with a larger ongoing project: Alcohol Action in Rural Communities (AARC), which is a cost-benefit analysis of community-wide interventions to reduce alcohol-related harm in rural Australia. Given the study involves 20 rural communities in New South Wales, Australia; much of the analysis is centred around data collected from these communities. This thesis examines the amount and patterns of alcohol consumption, some of the associated harms, the value of reducing these harms, plus professionals’ and the public’s opinions on interventions, viewed as an optimal solution to reduce alcohol-related harm for the communities within this study. First, those factors which affect individuals’ decisions regarding how much alcohol to consume are examined through econometric modelling of the demand for alcohol. Moreover, a theoretical model is derived whereby individuals choose both the intensity and frequency of alcohol consumption in order to maximise their utility. This is then used to examine those factors that affect the relationship between intensity and frequency of alcohol consumption for individuals within the 20 communities of the study. Secondly, the impact that this alcohol consumption has in terms of the effect on morbidity, crime and traffic accidents within these 20 communities is analysed. The relationship between selfreported quality of life using the EQ5D (a quality of life instrument) and self-reported risky alcohol use are examined using ordered Probit and Tobit models. Also, the relationship between community levels of risky drinking and crime and traffic accidents that occur in alcohol-related times is analysed, controlling for the underlying level of crime in the community by using the rate of incidents that occur in non-alcohol-related times. It is found that rural communities in Australia are experiencing a sizeable amount of potentially avoidable harm due to risky alcohol use. Thirdly, the value of reducing alcohol-related harm in these communities, in terms of the amount households are willing to pay for these reductions, is estimated using contingent valuation methods. Individuals’ willingness to pay for a percentage reduction in alcohol-related harm is estimated using both a postal questionnaire for the 20 communities, plus a face-to-face questionnaire conducted in two of these communities. The face-to-face questionnaire is also used to conduct a double-bounded dichotomous choice experiment, to investigate the willingness of households to pay for a reduction in a number of different types of alcohol-related harm. Finally, the views on the optimal policy options to reduce alcohol-related harm for rural communities in Australia are examined for both professionals and the general public. A sample of drug and alcohol (D&A) professionals were asked to allocate a budget of $100,000 to a number of interventions in order to reduce alcohol-related harm in a hypothetical rural community. The D&A professionals most commonly selected interventions include training general practitioners (GPs), targeting high-risk groups, developing a harm-reduction code of practice, expanding social work services and the training of emergency department staff. Additionally, individuals from the general public were asked via a postal questionnaire to allocate a percentage of total funds to eight intervention areas in order to reduce alcohol-related harm in their communities. The top three intervention areas given the most funding, on average, by the public were school-based interventions, educational messages in the media, and greater police enforcement. There is no doubt that alcohol consumption causes a substantial amount of harm for rural communities within Australia. This thesis has provided information to inform the development of interventions tailored to specific communities and has derived estimates which can be used to help evaluate the cost-benefit of these interventions. There is still additional research to be done in order to obtain more accurate estimates of the exact effect alcohol has on rural communities and thus comprehensively evaluate which interventions are likely to be the most cost-effective in reducing this harm.

The Economics of Developing a Long-Distance Walking Track in North Queensland

Cook, Averil — 2008-11-21T00:00:00Z

Walking tracks with provision for overnight stays exist in many countries. They are a tourism drawcard and some (e.g. the Milford Track in New Zealand) have icon status. In Australia, long-distance tracks exist in most states but had not until recently been developed in north Queensland. The working hypothesis for this thesis is that a new long-distance walking track in the tropical rainforest environment could be a valuable recreation asset for the region, and a major tourism attractor. Since a long-distance walking track in a natural environment would be situated in a rural region away from major cities, there is potential for tourism expenditure by long-distance hikers to contribute positively to the economy of remote towns. It is proposed that a walking track can be created relatively easily in the rainforests if disused former logging roads are used as the basis. The new walking track on a logging road base could be developed at moderate cost, and with minimal ecological and environmental disturbance. A new track created within a protected natural area is usually regarded as a public good and most associated costs may be considered to be appropriately funded through the taxation system. However, it may be argued that the recreational use of a long-distance walking track provides benefits to those who use it, and that hikers should contribute towards the recovery of managerial costs. An appropriate level of user fee may be obtained from a market model. In this thesis, an annual market model is estimated for the recreation service which provides a short-term efficient price. A long-distance walking track is an investment in recreation infrastructure the benefits of which are intergenerational. Thus efficiency in the long-term is also an important consideration. Both a static analysis and cost-benefit dynamic analysis are presented in this thesis. When a track does not exist (as was the case in north Queensland when this thesis commenced) or when it is under construction (as when the thesis was nearing completion), direct evaluation is not possible and so demand (consumer surplus) and supply (marginal cost of recreation service) estimates for a new track must be obtained from other sources. A key original contribution in this thesis is the application of economic transfer to derive a market model for a proposed recreation service infrastructure item, and a further application of economic transfer involves the use of the benefit level from the market model as an input into the cost-benefit analysis. Demand estimates have been obtained from surveys of visitors on two other walking tracks in north Queensland. Zonal travel cost methodology has been applied to the survey data to develop demand curves for these long-distance hiking opportunities and measures of value in terms of consumer surplus. Zonal rather than individual travel cost was necessary since most respondents were walking the particular track for the first time. Since the Centenary of Federation in Australia in 2001, when seed funding was made available, some new long-distance walking tracks have been developed in the Queensland Wet Tropics World Heritage Area. One of these has been selected as the case study developing track for this thesis. Demand and cost estimates for the new trail have been transferred, with appropriate adjustments, from the studies conducted on the two other trails. An interesting feature in this transfer process is that close substitutes exist for the target walking track but not for either of the two source walking tracks. An innovation in this thesis is the development of a market model for the new track. Two market models are derived, one from each of the source tracks, and are used to determine the socially efficient price and visitation levels. These may be used by management as a basis for the setting of user fees. The equilibrium values obtained from the static analysis have also been incorporated into the dynamic analysis together with the consumer surplus estimates from the travel cost demand curve. The equilibrium quantities provide the basis for an estimate of the visitation level expected for the new track on which many of the continuing management costs depend. Two scenarios (with and without hut infrastructure) have been investigated in cost-benefit analyses. Both scenarios were found to be economically worthwhile.

The economics of developing water resource projects in the Ethiopian Nile River basin : their environmental, and transboundary implications

Mekonnen, Kefyalew. — 2011-09-14T00:00:00Z

The economics of interstate freight transport regulation and competition in West Malaysia

Gan, Saiu-Chiew. — 2011-07-11T00:00:00Z

THE ECONOMICS OF RENEWABLE ENERGY POLICY WITH SPECIAL REFERENCE TO AUSTRALIA

Ivanova, Galina — 2008-11-21T00:00:00Z

This thesis examines some aspects of the economics of the Australian Federal Governments Mandatory Renewable Energy Target (MRET) policy with a special reference to Queensland. The objective of this policy is to increase the market share of renewable energy technologies in the Electricity Supply Industry (ESI) in Australia. The Renewable Energy Certificates (RECs) market was established to achieve the desired market share of renewable energy technologies. These certificates are issued to renewable energy generators for each megawatt hour of eligible renewable electricity produced by generators. In Australia, electricity retailers and other large consumers of electricity have to buy a certain amount of RECs and then surrender RECs to the renewable energy regulator in order to comply with the policy. If retailers and other large consumers of electricity do not have the required amount of RECs by a certain day they have to pay a specified penalty. Renewable energy technologies are less emission intensive than conventional fossil-fuel electricity generation technologies. Therefore, the increased market share of renewable energy technologies is expected to result in reduced emissions from the electricity industry and corresponding improvements in environmental quality. The problem, however, is that private costs of producing electricity from renewable energy technologies are in general more expensive than private costs of producing electricity from conventional fossil-fuel generation technologies. Further, the recent structural reforms of the Australian electricity sector and removal of legal barriers to entry in generation have contributed to the private cost advantage which fossil - fuel electricity generation has in general over renewable technologies. This thesis investigates the options available to policymakers to internalise externalities in the ESI, the cost of emissions from the ESI, and benefits of increasing the market share of renewable energy technologies. It also looks at the renewable energy policies adopted in various countries. The thesis presents simulation models examining the impact of the MRET policy as if it were a state based scheme adopted by the state of Queensland. Models also illustrate how a carbon tax can change the merit order of the Queensland ESI. It highlights the advantages and disadvantages of the MRET policy. This thesis looks at the supply side by examining main components and effects of the Australian MRET policy including, using the methodology of experimental economics, the effects of the penalty for non-compliance in the context of a specific market structure. Increasing the market share of the renewable energy technologies is also approached from the demand side. This thesis examines consumers willingness to pay (WTP) to protect the environment. Important influences on WTP higher prices in order to protect the environment were analysed on the international and Australian levels using the 1993 and 2000 International Social Survey Programme (ISSP) data and the Australian data from the 2003 Australian Survey of Social Attitudes (AuSSA). This thesis also employs a contingent valuation survey that was developed to determine the extent to which consumers are willing to pay to protect the environment, to support the MRET policy and to pay for electricity generated from renewable energy. The contingent valuation survey was administered in Queensland. The simulation results indicated that there were enough available low cost renewable energy resources (such as biomass) in Queensland if the state were to adopt the Federal Governments MRET scheme policy objectives and policy instruments (such as RECs market and a penalty for non-compliance) as a state scheme. However, it is unlikely that all these resources will be employed due to several factors (e.g., the seasonal nature of some of the biomass resources, such as waste from sugar mills). Therefore the price of RECs could be quite high and just below the penalty. It was also concluded that the presence of a penalty for non-compliance in the RECs market can lead to a high RECs price. Wrong market price signals could lead to inefficient investments in renewable energy technologies. Several important results emerged from the analysis of WTP for the protection of the environment: 1) in most countries considered, marginal willingness to pay to protect the environment was less in 2000, than in 1993; 2) respondents were more inclined to state that they were willing to pay higher prices in order to protect the environment than they were to pay higher taxes; 3) respondents were more reluctant to pay for an environmental good if the good is provided on a very large scale, such as the global environment, compared with an environmental good provided on a small scale which impacts mainly the local environment; 4) WTP to protect the environment is associated strongly with perceptions of the risk of environmental destruction; and 5) although there are many similarities among the characteristics of the consumers in different countries who are willing to pay more for environmental protection, the country specific research is required to account for local specifics. The analysis of the data obtained by the Queensland survey showed that the demand side can support some investments in low cost renewable energy technologies. Consumers indicated a strong preference for voluntary support of support renewable energy technologies compared with the mandatory support as required by the MRET policy. Policy recommendations are presented.

The economics of the church-firm : a case study of Churches of Christ in New South Wales : a non-profit organisation

Fiedler, Mervyn Rupert George. — 2010-11-02T00:00:00Z

The Effect and Efficacy of E-government administration

Amy Cooper — 2011-11-30T00:00:00Z

Determining the optimum form of administration is the ideal of public administration theory. This thesis begins by acknowledging the long-standing debate between public administration theorists over the best way for governments to organise and manage for successful outcomes. E-government administration is a more recent entrant into this debate. This thesis determines the effect and efficacy of e-government administration by pursuing answers to the following three research questions: 1: What causes divergence between traditional and e-government administration structures? 2: How has e-government administration affected traditional public administration? 3: Which e-government administration style produces the best e-government outcome? Asking what caused the divergence between virtual and traditional administration structures results in two conclusions. First, the OECD e-government administration classifications provide a very useful framework and classified each case study’s e-government administration to show if and how they differed from traditional public administration structures. Second, the formal and informal institutions at play in a given country are the single greatest influence on the development of its particular e-government administration style. Next, the effect of e-government administration on public administration was researched in the context of two leading theories on the subject. Fountain’s (2001; 2006) Technology Enactment Framework suggests how e-government could affect public administration (Fountain 2001; 2006). Dunleavy et al.’s (2005; 2006) Digital Era Governance suggests the effect of this change has been to move governance beyond New Public Management trends to a new era of digital governance. Case study data supports both theories. This thesis contributes significantly to and modifies Fountain’s work, which until now has been most often tested on US data. Having three additional countries reflect Fountain’s Framework greatly assists its usefulness as an explanatory tool to illustrate how technology (here, e-government) affects institutional structures (or public administration). This research also contributes to Dunleavy et al. Though their theory had been tested in each case study country, the level of analysis was particularly deep in this research and yet remains in support of their proposition. Collectively, this research provides a pool of evidence in support of each theory that is too significant to allow either to be considered as significantly flawed. To provide a mechanism in which both can be considered accurate, it is argued that Fountain’s TEF provides the logisitical framework through which Dunleavy et al.’s DEG is able to take root. This line of argument also contributes to the broader public administration literature. The two dominant theories provided by Fountain and Dunleavy have not previously been tested in conjunction with one another. The argument that each supports the other has provided an alternate explanation to the usual juxtaposition of the two as contrasting viewpoints. Lastly, asking which e-government administration produces the best e-government outcome was designed to advance the field of public administration by testing centralisation theory. The question was designed to assist in the debate over the best way to organise and manage for successful outcomes. Researching its answer followed a logical progression that demonstrates no significant flaw and in fact works hard to dispel any concerns on that front. It was found that centralised administrations did not produce better e-government outcomes on a municipal, national nor global scale. The overwhelming indication of these results is that there is no causal relationship between centralised administrations and good e-government outcomes. This is not an insignificant finding. The pursuit of excellence in public administration, however defined, remains a key concern in developed countries. The OECD is even now in “talks with the producers of the major global e-government surveys with a view to launching new e-government indicators that focus on public sector performance” (Hicks 2010). For countries seeking public administration excellence in their online application of e-government, these results demonstrate that organising and managing e-government administration in a centralised fashion has not produced top quality e-government outcomes. In sum, this research has made the effect and efficacy of e-government administration clear. The efficacy of e-government is not tied to the centrality of its administration and its effect, brought about by how civil servants use and perceive technology, has been to usher in a new era of digital governance.

The effectiveness of CBT in the treatment of depression and anxiety occurring both in isolation and in conjunction with other serious psychiatric conditions as seen within a community mental health service.

Katherine Macdonald — 2009-10-15T00:00:00Z

Abstract Background: Cognitive Behaviour Therapy, (CBT) is well established as an effective treatment for depression. Its applicability in routine public mental health practice is however unknown, as most published studies excluded participants with suicide risk or if co-morbid with other disorders such as schizophrenia or bipolar affective disorder. Clients of public mental health services are characterised by symptom severity, chronic course of illness, treatment resistance and / or co-morbidity. In order to determine whether CBT has utility in routine public mental health practice, it is important to find out whether symptoms of depression (and anxiety) in this client population will respond to a course of CBT provided as part of standard care. Aims and Hypotheses: This effectiveness study aimed to ascertain if CBT is effective in treating depressed and/or anxious symptoms when such symptoms exist within the clinically more complex population found within Community Mental Health Services / Settings, (CMHSs). It was hypothesised that clients receiving CBT would show reliable and clinically significant improvement in symptoms of depression and anxiety but that the amount of improvement would be less than that reported in efficacy studies with less complex client groups. Method: This was a repeated measures, uncontrolled intervention study with results benchmarked against published data. Forty six adult clients of the Inner North Brisbane Mental Health Service (INBMHS) with diagnoses of Depression and / or Anxiety, in isolation or in conjunction with Schizophrenia, Bipolar affective disorder, or a Personality Disorder were treated with an eight (8) session manualised CBT program as part of routine clinical care. Standardised measures of depression, anxiety and stress were taken at time of referral, time of the commencement of treatment, time of treatment completion and at six-month post completion of treatment. Results: Participants showed reliable and statistically significant improvement in self reported symptoms from commencement to completion of treatment. Gains were retained at follow-up. Effect sizes were in the moderate to large range and improvements were clinically significant for approximately one third of the participants. Conclusions: CBT seems to be an effective treatment for depression and anxiety where such symptoms exist within a mental health population. Further research addressing the limitations of this study would add strength to the argument that the mental health population could benefit from the broad availability of such treatment.

The effectiveness of dialectical behaviour therapy in routine public mental health settings: an Australian controlled trial

Pasieczny, Nathan — 2013-03-11T12:38:22Z

THE EFFECTIVENESS OF KIKUYU PASTURES IN THE CAPTURE OF NITROGEN FROM DAIRY EFFLUENT ON THE ATHERTON TABLELANDS

Silver, Bradley Allan — 2008-11-21T00:00:00Z

Pressure on dairy farmers to remain viable since the industry was deregulated in July 2000 has accelerated the rate of production intensification. Milk is still produced on a year round basis in Queensland but now decreased milk price and increasing production costs are requiring farmers to intensify to a greater extent. The industry is still primarily pasture based but there is an increasing trend to feed larger numbers of cows in some form of purpose built intensive feeding system. Increased intensification results in an increased reliance on supplementary feeding, a greater need to ensure peak pasture production with fertiliser and more pressure on the waste management system. A common waste management system on the Atherton Tablelands of northern Queensland requires storage of all effluent in a single long term storage pond. This waste is then applied to pasture in the dry season through a sprinkler system. Alternatively effluent may be applied on a twice daily basis as yards are cleaned after milking. Although tropical grass can use large amounts of nutrient, potential loss of nutrients by run-off and leaching can occur in the wet season of tropical north Queensland when effluent is applied daily. This study was designed to test the management strategy of applying dairy effluent to a tropical pasture in summer when the pasture growth and therefore nutrient requirement is at its highest. The objective was to determine nutrient use efficiency of kikuyu and to determine leaching losses of nitrogen and therefore the potential environmental hazard. Stored dairy effluent was applied through the irrigation system at 0, 18.5, 42.4, 56.0 and 74.6 kg TKN ha‾¹ over the wet season to a kikuyu (Pennisetum clandestenin) dominant pasture which had been sown to annual ryegrass (Lolium multiflorum) the previous autumn. Irrigation water was applied at rates which were in inverse proportions to dairy effluent. Pasture yield was measured every three weeks over a 107 day period. No significant difference in total pasture dry matter yield, pasture growth rate, plant nitrogen percent or total plant nitrogen yield was measured. Total pasture yields were 5243, 5808, 6213, 6035 and 5836 kg DM ha‾¹ over 5 harvests. Pasture growth rate ranged from 33.4 to 78.9 kg DM day‾¹. Mean plant nitrogen yield was 161.8, 178.2, 194.2, 197.5 and 196.9 kg ha‾¹. There was no significant difference in soil N and soil cation concentration (except sodium) to a depth of 80 cm at the completion of the trial period. At 50 to 80 cm soil depths treatments 1, 4 and 5 were significantly different to treatments 2 and 3 in sodium concentration. There was no difference in soil N levels to a depth of 20 cm prior to or after the treatment application. Following extensive measurement and sampling of leachate it was calculated that 29.1 and 86.8 kg ha‾¹ of total N was leached to 50 cm from treatments 1 and 5 respectively. Measurements of soil N, plant N and leachate N indicate that there was a gain of 20 kg N ha‾¹ in the N budget for treatment 1 and a gain of 55 kg N ha‾¹ from the system during the trial period for treatment 5. Possible reasons for these results are discussed. The results indicate that it is difficult to apply dairy effluent to pastures during the summer wet season on the Atherton Tablelands without nitrogen losses through leaching. However given the large amounts of organic N and the potential for high rates of mineralisation, substantial N losses can occur without any additional N application. The results also suggest that the yield of a tropical pasture, which follows a well fertilised annual temperate pasture such as ryegrass, is not enhanced by the application of dairy effluent during this time. However, pasture quality may be improved by the application of dairy effluent.

The effect of aestivation on the musculo-skeletal system of the green striped burrowing frog, Cyclorana alboguttata

Hudson, Nicholas J. — 2007-08-24T00:00:00Z

The effect of alloy composition and microstructure on the hot cracking of vertical direct chill cast aluminium alloy billet

Instone, Stephen S — 2011-12-14T00:00:00Z

The effect of Australian gudgeon (Hypseleotris spp.) on phytoplankton in a subtropical reservoir, and implications for food web manipulation

Hunt, Richard Joseph — 2007-08-24T00:00:00Z

The effect of cadmium on benzo[a]pyrene-induced DNA damage and repair in Sprague-Dawley rats

Peng, Cheng. — 2007-08-24T17:52:15Z

The effect of case conferences between general practitioners and palliative care specialist teams on the quality of life of dying people

Geoffrey Keith Mitchell — 2007-08-24T00:00:00Z

The effect of cell hydrodynamics on flotation kinetics

Tabosa, Erico Oliveira — 2012-10-18T11:55:46Z

THE EFFECT OF CHRONIC LOW BACK PAIN ON THE SIZE AND ACTIVATION OF THE LUMBAR MULTIFIDUS MUSCLE

Wallwork, Tracy Leigh — 2008-11-21T00:00:00Z

The lack of control of lumbar stability is thought to be a major factor in the aetiology and chronicity of low back pain. The lumbar multifidus muscle is considered to play a significant role in maintaining lumbar stability and stiffness. The aim of this study was to use clinical measures to compare lumbar multifidus muscle in chronic low back pain patients and unimpaired subjects. Sixteen subjects with chronic low back pain and 16 unimpaired subjects were assessed in the study. Cross-sectional area (CSA) and contraction size of multifidus were measured on both sides and at individual vertebral levels, from L2 L5, using realtime ultrasound. The differences between the chronic back pain and unimpaired groups were statistically significant for both cross-sectional area and contraction size measures. In the unimpaired group, the contraction size of multifidus was greatest at the L5 segmental level, and then decreased in size at higher lumbar levels. In the chronic low back pain group, the contraction size was the same at L4 and L5 levels and contractions were less at these levels than those at L2 and L3. Three way interactions showed a significant interaction (p<0.05) between vertebral levels, change in thickness and group. Contrasts revealed a significant difference (p<0.05) between upper lumbar levels (L2 and L3) and lower lumbar levels (L4 and L5) across groups. In the unimpaired group, the contraction size of multifidus was greater at lower lumbar levels (L4 and L5) than upper lumbar levels (L2 and L3), while in the low back pain group, the contraction size was less at lower lumbar levels than upper lumbar levels. A similar pattern occurred with multifidus CSAs. In the unimpaired group, CSA was greatest at L5 and gradually reduced at higher lumbar levels. In the chronic back pain group, CSAs were the same at L5 and L4 and only slightly greater than L3. Two way interactions showed a highly significant difference (p<0.01) between groups across vertebral levels. There was a significant difference between upper lumbar levels (L2and L3) and lower lumbar levels (L4 and L5). Lower lumbar levels were less in the chronic low back pain group than the unimpaired group, when compared to upper lumbar levels. Estimated marginal means showed that CSA at L5 was significantly less in the chronic low back pain group (confidence interval >95%). Results of the study indicate that chronic low back pain patients have poorer muscle activation and greater muscle wasting of multifidus muscle at the lower lumbar levels compared with higher lumbar levels, than normal subjects. Clinical programmes should aim to restore multifidus muscle activation and size, in patients with chronic low back pain.

The Effect of Chronic Stress on Cellular Immunity: A Possible Alleviation by Praescent™

Neville Hartley — 2012-02-27T00:00:00Z

It is well known that chronic stress affects the immune system which is often suppressed during chronic stress affecting both cellular and humoral components of immunity. During chronic stress excessive reactive oxygen species (ROS) are also produced which contribute to cellular damage, inflammation, cancer, and immune dysfunction. This project investigates whether Praescent™, a mixture of plant derived chemicals; cis-3-hexen-1-ol (0.03%), trans-2-hexenal (0.03%) and alpha-pinene (0.015%), can alleviate the negative effects of chronic stress on cellular immunity. In addition it explores whether there is a correlation between high levels of ROS and immune suppression. To answer these questions C57BL/6 mice were restrained for 35 consecutive days (4 h/day), injected with an antigen (ovalbumin) and exposed aromatically to Praescent™. Stress hormones were determined by radioimmunoassay (RIA) measuring the total and free compartments of corticosterone within the blood plasma, and adrenals were weighed as a percentage of body weight to determine the physiological effects of chronic stress. The immunological response was evaluated using enzyme-linked immunosorbent assay’s (ELISAs) to quantify immunoglobulin-gamma (IgG) antibodies, and their subtypes IgG1 and IgG2a, and the ratio of IgG1 to IgG2a was also evaluated. Leukocyte numbers were determined by microscopy. The oxidative status was evaluated using 2′,7′-dichloro- fluorescin diacetate (DCFH-DA), a sensor of ROS. During chronic stress high levels of ROS were detected accompanied by a corresponding decrease in the number of leukocytes. In addition, there was a shift from cell-mediated immunity toward antibody-mediated immunity as evident by an increase in the IgG1 to IgG2a ratio. Praescent™ significantly reduced ROS levels and prevented the reduction of leukocytes following chronic stress; however it did not prevent the stress-induced shift toward an antibody-mediated immunity. Furthermore, Praescent™ prevented the stress-induced increase in adrenal weights. These results suggest that Praescent™ is an effective agent alleviating oxidative stress and preventing stress-induced alterations to the immune system.

The Effect of Comminution Mechanism on Particle Properties: Consequences for Downstream Flotation Performance

Timothy Vizcarra — 2011-03-31T00:00:00Z

Many particle properties critical to the flotation process originate from the comminution stage. A better understanding of how these properties are affected by the methods of particle size reduction used will help determine whether current strategies for comminuting ores can be modified to further enhance particle floatabilities. This thesis investigates how different comminution mechanisms affect the properties of ore and mineral particles and assesses how changes to these properties subsequently affect flotation performance downstream. Three ores were selected for this study: Northparkes (a low-grade, copper porphyry ore); Ernest Henry (an iron-oxide hosted copper-gold ore); and Century (a high-grade strataform zinc ore). These were each comminuted to various particle size distributions using a hammer mill and a piston-die compression unit (simulating the breakage mechanisms used by high pressure grinding rolls). Progeny particles were then characterised using the JKMRC’s mineral liberation analyser (MLA) on a size-by-size basis. It was found that size-by-size liberation properties were independent of both the mechanism used to comminute the ore samples, as well as the final size distribution of the progeny particles. This was observed for both valuable and gangue mineral phases. Variations in the liberation properties of a mineral in a given size fraction were explained in terms of the effect of mineral grade upon the statistical uncertainties of liberation measurements. Rather than being dependent on the method of breakage used to comminute an ore, liberation properties were instead found to be dependent on the mechanical properties of associated mineral phases. Where large differences existed between the mechanical properties of associated minerals, the “harder” mineral was found to be conserved during the breakage process, deporting directly to high-grade liberation classes upon size reduction without forming composite particles. These effects were not observed for “softer” minerals. The mechanism of comminution used was not found to have any effect on the liberation properties of the discharge particles. However, relationships were found between the shape properties of particles (quantified using the MLA) and the breakage devices from which they were discharged. Samples comminuted in the hammer mill were found to be comparatively more round than those discharged from the piston-die compression unit which, conversely, were more angular. This was attributed to rebreakage events during the hammer mill grinding process whereby topographical features on particle surfaces (such as sharp edges and corners) were chipped away, resulting in the production of round, spherical particles. The effect of particle angularity on flotation performance was subsequently tested by floating sized, fully liberated chalcopyrite particles that were comminuted in either the hammer mill or piston-die compression unit, and retrospectively analysing the angularity properties of the timed concentrates. It was found that, in the absence of collector, angular chalcopyrite particles exhibited faster flotation kinetics than comparatively round particles, likely due to the enhancement of particle-bubble adhesion mechanics as hypothesised by past studies. Additionally, surface chemistry analysis conducted in collaboration with the Ian Wark Research Institute also showed that the comparatively angular concentrates also had higher degrees of surface coverage by hydrophobic polysulphide species, and this is also likely to have contributed to their faster flotation kinetics. The results of this thesis clearly show that mineral liberation properties cannot be controlled by the method of breakage used. However, it is expected that the results will aid in the development of both empirical as well as fundamental mineral liberation models. Additionally, it is shown that a potential method of enhancing particle floatability during the comminution stage is through the manipulation of particle shape properties. This has important implications for the development of property-based flotation models as well as for the eventual integration of comminution and flotation models.

The effect of deeply subducted oceanic slabs and associated sediment on the chemical evolution of the mantle and on mantle-derived melts

Murphy, David Thomas. — 2011-07-11T10:28:45Z

The effect of developmental temperature on muscle morphology and growth of mangrove jack Lutjanus argentimaculatus, silver perch Bidyanus bidyanus and barramundi Lates calcarifer

Carey, Geoff — 2008-11-21T00:00:00Z

The early growth and development of fish muscle is highly temperature dependent. Changes in the thermal regimes of developing fish embryos can induce differences in the number and size of muscle fibres (muscle cellularity) in just hatched larvae. These differences show considerable variation, with the complex pattern of magnitude and longevity of myogenic change showing high species-specificity. Myogenic responses to early temperature in several fish species studied so far show no inter-species/genus patterns, although responses are repeatable within species/genus. In some species, a higher than normal incubation temperature increases muscle cellularity, whereas in others, a lower incubation temperature increases muscle cellularity. As early muscle cellularity can be a strong predictor of future growth patterns in fish, this response has prompted considerable scientific interest. Early muscle cellularity may also influence recruitment success, locomotor ability, and ultimately fitness, and as such it is important to improve understanding in this area. In this study, just fertilised eggs of mangrove jack Lutjanus argentimaculatus, silver perch Bidyanus bidyanus and barramundi Lates calcarifer were introduced to three different incubation temperatures, to assess the effects on early muscle growth and development. The thermal regimes applied to each species corresponded to an ambient (spawning) temperature, a warm temperature, and a cool temperature, all within the particular thermal tolerances of that species. Larvae of B. bidyanus and L. calcarifer were on-grown to assess subsequent effects of incubation temperature. Additionally, five day old larvae of L. calcarifer were transferred from the high and low temperatures back to ambient temperature to ascertain the effects on muscle parameters, growth rates and locomotory ability. These species were chosen as ideal candidates for examination in this study as they are important aquaculture species both in Australia and internationally, and all have well established hatchery protocols offering a reliable supply of fertilised eggs. Also they allow the examination of early thermal effects on both salt-water spawning (L. argentimaculatus, L. calcarifer) and fresh-water spawning (B. bidyanus) species. After retrieval from spawning tanks, fertilised eggs of L. argentimaculatus were incubated till hatch at 26°C (cool), 29°C (ambient) and 32°C (warm); those of B. bidyanus were incubated at 22°C, 25°C and 28°C; and those of L. calcarifer were incubated at 26°C, 29°C and 31°C. Warmer incubation temperatures hastened hatching in all three species, whereas cooler incubation temperatures delayed hatching. Average time to 50% hatch of L. argentimaculatus incubated at 26, 29 and 32°C was 19, 17.5 and 13 hours, respectively; of B. bidyanus incubated at 22, 25 and 28°C was 37, 34 and 30 hours, respectively; and of L. calcarifer incubated at 26, 29 and 31°C was 19, 15 and 13 hours, respectively. Incubation temperature had a significant effect on the length of just-hatched B. bidyanus, with incubation at 22°C producing shorter larvae (3.49 ± 0.09 mm) than those incubated at 25°C (4.18 ± 0.09 mm) or 28°C (4.39 ± 0.09 mm). By 12 days post-hatch, however, those incubated and grown at the warm (28°C) temperature were significantly longer (6.73 ± 0.14 mm) than those grown at 25°C (5.92 ± 0.22 mm). The length of just hatched L. argentimaculatus or L. calcarifer was unaffected by incubation temperature, although by nine days post-hatch barramundi incubated and grown at the warm (31°C) temperature were significantly longer (4.90 ± 0.18 mm) than those incubated and grown at 29°C (4.22 ± 0.23 mm), 26°C (3.95 ± 0.13 mm), or transferred from the warm (3.98 ± 0.25 mm) or cool (4.01 ± 0.21 mm) temperatures. Transverse sections of just hatched larvae from all incubation temperatures showed muscle components at an immature stage of development, revealing myotubes yet to differentiate to mature inner (white) muscle fibres. Incubation temperature had a significant effect on the number of immature inner muscle fibres in just hatched L. argentimaculatus and L. calcarifer, with incubation at the warm temperature increasing fibre number in L. argentimaculatus (315.60 ± 13.07 for those incubated at 32°C, 275.00 ± 16.90 for those incubated at 29°C, 253.00 ± 13.80 for those incubated at 26°C); and incubation at the cool temperature increasing fibre number in L. calcarifer (350.00 ± 14.21 for those incubated at 26°C, 327 ± 11.44 for those incubated at 29°C, 292.00 ± 14.49 for those incubated at 31°C). Conversely, inner muscle fibre area significantly increased at the warm incubation temperature in L. calcarifer (12.23 ± 0.66 µm2 for those incubated at 31°C, 9.75 ± 0.45 µm2 for those incubated at 29°C, 10.33 ± 0.75 µm2 for those incubated at 26°C), whereas incubation at the cooler incubation temperatures increased inner muscle fibre area in L. argentimaculatus, although not significantly (P = 0.09). Inner muscle fibre cellularity of just hatched B. bidyanus was unaffected by incubation temperature. The total area of superficial (red) muscle fibres and the proportion of superficial to total fibre area in just-hatched L. calcarifer were significantly affected by incubation temperature, with incubation at the cool temperature (26°C) increasing both the total area (1816.23 ± 136.16 µm2) and proportion (0.21 ± 0.01) of superficial muscle fibres compared with incubation at 29°C (974.95 ± 108.42 µm2 and 0.14 ± 0.01 for total superficial fibre area and proportion of superficial to total muscle fibre area, respectively) and 31°C (1049.09 ± 70.60 µm2 and 0.13 ± 8.7 x 10-3). These parameters were unaffected by incubation temperature in L. argentimaculatus and B. bidyanus. By nine days post-hatch, differences in the total superficial fibre area between non-transferred and transferred treatment groups of L. calcarifer were no longer significant, whereas differences in the proportion of superficial to total muscle fibre area still were, with those hatched and grown at the warm (31°C) temperature having a significantly reduced proportion of superficial muscle area (0.05 ± 6.66 x 10-3) compared with those incubated and grown at 29°C (0.08 ± 7.77 x 10-3) and 26°C (0.09 ± 5.66 x 10-3), and those incubated at 26°C and transferred to 29°C (0.07 ± 5.31 x 10-3), and incubated at 31°C and transferred to 29°C (0.06 ± 6.91 x 10-3). Growth rates of L. calcarifer from the five treatment groups were assessed over a 12 week trial. Differences in mass and standard length increase between treatment groups were not significant (P = 0.060, P = 0.071 for mass and standard length after twelve weeks, respectively). However, differences between treatment groups increased between six and 12 weeks (P = 0.075, P = 0.100 for differences in mass and standard length after six weeks, respectively), indicating that a longer period of testing may have resulted in significant growth differences between treatment groups. Additionally, mass increased considerably more in the group incubated at the coolest temperature and transferred to the control temperature (26/29°C), than in any other treatment group (37.10 % more than the 26/26°C group, 23.80 % more than the 29/29°C group, 21.00 % more than the 31/29°C). It is proposed that the superior mass increase seen in this treatment group may have been imprinted on the myogenic program of L. calcarifer after incubation at the cool (26°C) temperature, which resulted in an increase in inner muscle fibres at hatch, and a subsequently improved growth rate. There was no evidence that incubation temperature affected the burst (Umax) or sustained (Ucrit) swimming ability of L. calcarifer. However, barramundi incubated and reared at the cool (26°C) temperature performed significantly better at 26°C test temperature (101.76 ± 3.70 cm.s-1) than those of other treatment groups (83.22 ± 6.29 cm.s-1 for the 29/29°C group, 85.40 ± 9.70 cm.s-1 for the 31/31°C group, 87.30 ± 4.10 cm.s-1 for the 26/29°C group, 76.42 ± 5.93 cm.s-1 for the 31/29°C group), indicating the ability of L. calcarifer to thermally acclimate burst swimming. Additionally, swimming ability was significantly affected by the test temperature, with Umax of fish from all treatments highest at 29°C test temperature, and the swim speeds of all treatment groups combined significantly lower at 26°C for Umax (86.90 ± 2.80 cm.s-1 at 26°C, 103.20 ± 3.40 cm.s-1 at 29°C, 96.90 ± 3.90 cm.s-1 at 31°C) and Ucrit (58.89 ± 8.90 cm.s-1 at 26°C, 60.90 ± 6.50 cm.s-1 at 29°C, 62.40 ± 6.20 cm.s-1at 31°C). Lower test temperature therefore tended to depress both burst and sustained swimming ability in L. calcarifer. The positive results from this study indicate that the growth rate of L. argentimaculatus and L. calcarifer may be enhanced by the application of thermal manipulation in the hatchery phase of development. Additionally, there was a demonstrated affect of early thermal regimes on the subsequent swimming ability of L. calcarifer. Possible implications and future directions for this research are discussed.

The effect of developmental vitamin D3 deficiency on brain development, behaviour and immune function in the Sprague-Dawley rat

Louise Harvey — 2009-03-23T00:00:00Z

Epidemiological evidence from season of birth and migrant studies has led to the proposal that developmental vitamin D3 (DVD) deficiency may be a risk factor for schizophrenia. Concurrently, there has been recent intense interest in vitamin D3 as a modifying factor in the development of immune responses. However, the effects of DVD deficiency on immune function remains unknown. Thus, a model of DVD deficiency has been developed in Sprague-Dawley rats. Briefly, female rats were maintained on a vitamin D3 deficient diet prior to and during gestation. At birth dams were returned to a vitamin D3 replete diet. Post-weaning their offspring, the DVD-deficient rats, were maintained on a vitamin D3 replete diet. Therefore, this model represents a transient, prenatal vitamin D3 deficiency. A number of structural and cellular changes have been described in the DVD-deficient rat brain, including ventriculomegaly, decreased growth factor expression, and increased rates of mitosis. These changes are correlated with altered adult behaviour in the DVD-deficient rat, including a locomotor sensitivity to novelty. This thesis will focus on extending these findings and characterising immune function in the DVD-deficient rat. Vitamin D3 can affect cellular differentiation and is anti-proliferative and pro-apoptotic in many tissues including the brain. The effect of DVD deficiency on brain development has been restricted to neuronal cells in vivo and in vitro. However, the effect of this exposure on glial cell maturation and phenotype was unknown. The experiments reported in this thesis demonstrated that primary cortical glial cell cultures from DVD-deficient rat neonates displayed a similar phenotype and maturational status compared with cells from control rats. Learning and memory was examined in this model by exploring the phenomenon of latent inhibition. DVD-deficient rats displayed normal latent inhibition, however, they exhibited a subtle performance acquisition deficit during the early stages of the conditioned avoidance learning task. Extended handling and pre-exposure were able to ameliorate this deficit, though with this treatment normal latent inhibition was also abolished in both control and DVD-deficient rats. Ultrasonic vocalization and nociceptive threshold testing confirmed that alterations in peripheral sensation could not explain this performance acquisition deficit. The results suggested that anxiety or attentional mechanisms may have contributed to this rate of learning deficit. Finally, as vitamin D3 is a powerful immunoregulator, there is the potential for a transient DVD deficiency to induce a persistent alteration in the development and function of the immune system. This hypothesis was supported by findings that showed DVD deficiency resulted in a primed immune system, as indicated by an enlarged spleen, thymus and peripheral lymph tissue as well as increased pro-inflammatory cytokine production in response to an in vitro stimulation. However, these findings did not lead to an alteration in cell mediated immune response in vivo. The results from the research reported in this thesis indicate that a transient, prenatal vitamin D3 deficiency had a subtle yet significant effect on the immune system and behaviour of the adult rat. These findings add further weight to the body of evidence that link prenatal vitamin D3 status to various adverse health outcomes. The DVD-deficient rat model is an integral step in understanding prenatal vitamin D3 deficiency as a potential environment risk factor in the development of immune and psychiatric disorders.

The effect of elevated temperature on the ability to preserve disused muscle during metabolic depression in the aestivating ectotherm, Cyclorana alboguttata

Young, Karen Melissa — 2012-11-06T12:31:18Z

The effect of enacted capabilities on adoption and utilisation of innovative information systems : a study of small- and medium-sized enterprises.

Salleh, Noor Akma Mohd — 2008-11-21T00:00:00Z

This thesis is motivated by the need to establish a model covering innovative information systems (IS) adoption behaviours within small and medium-sized enterprises (SMEs). Studies on adoption behaviour related to innovative IS are devoting increasing attention to SMEs. Most prior studies, however, have still relied on models developed from studies of large firms. The applicability to SMEs of findings and models developed from large firm studies is not without question as SMEs are not miniature versions of large firms. SMEs face different challenges and opportunities from large firms. This thesis empirically examined issues on the adoption behaviours of innovative IS by SMEs. In line with this objective, two research questions were established. First, what are the critical determinants that allow SMEs to overcome inhibiting factors and adopt an innovative IS? Second, what are the critical determinants that ultimately activate and stimulate them to become enabled and actively utilise an innovative IS? The conceptualisation of enacted capabilities, adapted from the resource-based view of the firm is introduced. This thesis postulates that appropriate enacted capabilities facilitate SMEs to become enabled and actively utilise an innovative IS. These enacted capabilities include the level of IT skills and knowledge of the enterprises members, trust in technology, trust in trading partners, external experts support, and organisational culture Models incorporating aspects of the theory underlying the technology acceptance model (Davis, 1989), the diffusion of innovation theory (Rogers, 1995), and the resource-based view of the firm (Barney, 1991) were developed to describe the causal linkages between the determinants that activate and stimulate innovative IS adoption behaviour (i.e., from adopting to enabling to utilising innovative IS). One model was developed for the adoption stage and a second for the enablement and utilisation stages. The adoption stage model contains three main hypotheses. The first two hypotheses propose that enacted capabilities have a positive direct effect on both perceived net benefits and attitude towards adoption from a competitive advantage perspective. The third hypothesis proposes that perceived net benefits have a positive effect on attitude towards adoption form a competitive advantage perspective. The enablement and utilisation stages model contains four main hypotheses. The first two hypotheses propose that enacted capabilities and attitude have positive effects on perceived net benefits. The last two hypotheses propose that perceived net benefits and attitude towards adoption from a competitive advantage perspective have positive effects on the extent of enablement and usage of innovative IS. The hypotheses are tested using data obtained via a survey and follow-up interview. Responses were received from 206 SMEs of varying industries and sizes from the survey. Out of these 206 SMEs, follow-up interviews were conducted with twenty-one SMEs. The interviews utilise a combination of both open and closed questions. The questions for the follow-up interviews were based on findings derived from the survey. The innovative IS examined was the Malaysian governments electronic procurement system, known as ePerolehan. All government suppliers must register for the system and become enabled for use before they can start utilising the system. The results indicate that enacted capabilities possessed by SMEs affect perceived net benefits at all stages of adoption behaviours of SMEs (i.e., adoption, enablement and utilisation). More significantly, two aspects of enacted capabilities, top management IS skills and knowledge and trust in trading partners dominate the effect on perceived net benefits. Support from external experts dominates the effect on attitude at the adoption stage. Top management IS skills and knowledge and trust in technology have a negative effect on attitude at the time of adoption. Enacted capabilities also contribute to the extent of enablement and usage within SMEs. Furthermore, different categories of adopters differ in the set of enacted capabilities underlying their innovative IS adoption behaviour. Results also indicate that when SMEs perceived higher net benefits in adopting innovative IS, they have a positive attitude. The positive attitude generated at the time of adoption has a direct effect on the extent of enablement and usage. The influence of perceived net benefits differs at the different stages of adoption behaviour. At the utilisation stage, usage is affected by perceived net benefits, however, perceived net benefits do not affect the extent of enablement at the enablement stage. In conclusion, this thesis found that enacted capabilities display important roles as antecedents to perceived net benefits, and that perceived net benefits act as a mediator from enacted capabilities to attitude at the adoption stage. Enacted capabilities also display important roles as stimulators of the extent of enablement and usage. Thus, apart from requiring good ideas and financial resources, SMEs also require appropriate enacted capabilities when adopting, enabling and utilising innovative IS.

The Effect of Exercise on Cancer Risk Factors in Males with Barrett's Oesophagus

Brooke Maree Winzer — 2012-06-18T00:00:00Z

The incidence of oesophageal adenocarcinoma is rising faster than any other cancer. Overweight and obese males are at a particularly high risk of this cancer, especially those with the pre-malignant lesion, Barrett's oesophagus. If Barrett's oesophagus does progress to adenocarcinoma, prognosis is poor with a 5 year survival rate of 10-15%. At present there is a lack of evidenced-based interventions aimed at reducing oesophageal cancer risk in persons with Barrett's oesophagus. Oesophageal adenocarcinoma and Barrett's oesophagus have strong links with gastro-oesophageal reflux disease, overall body fatness and more specifically, abdominal obesity. Mechanisms mediating the positive relationship between adiposity and oesophageal adenocarcinoma may include the exacerbation of gastro-oesophageal reflux disease through mechanical factors, however metabolic mechanisms related to obesity may also be involved including altered concentrations of a number of obesity-related hormones. Exercise may be beneficial for those with Barrett's oesophagus due to its effects on reducing adiposity and improving levels of some obesity-related hormones; and possibly via reducing gastro-oesophageal reflux. Therefore exercise may be a suitable and feasible lifestyle treatment to lower oesophageal adenocarcinoma risk. However no trials have been conducted to date in adults with Barrett's oesophagus to evaluate the effect of exercise on mechanisms or "biomarkers" implicated in oesophageal adenocarcinoma development. The overall aim of this thesis is therefore to further understand the capacity of exercise to modulate oesophageal adenocarcinoma risk. To address this aim, two studies were undertaken: a systematic literature review and a randomised controlled trial. A systematic literature review was conducted to appraise previous trials evaluating the effect of exercise interventions on candidate biomarkers associated with cancer development. Findings of the review were used to inform the development of an exercise trial in persons with Barrett's oesophagus. A randomised controlled trial of exercise versus stretching was conducted in inactive males with Barrett's oesophagus (n = 33), aged 18 to 70 years, who were overweight or obese (body mass index 25.0 - 34.9 kg/m2). Participants were randomised to receive either a 24-week, moderate-intensity aerobic and resistance exercise intervention (60 min, 5 sessions/week) or stretching (45 min, 5 sessions/week). Outcomes were measured at baseline, 12-weeks and 24-weeks and included body composition (bio-impedance spectroscopy), abdominal adiposity (waist circumference), gastro-oesophageal reflux symptoms (Gastro-oesophageal Reflux Disease Impact Scale) and circulating concentrations of leptin, adiponectin (total, high molecular weight), C-reactive protein, interleukin-6, tumour necrosis factor-alpha, insulin and glucose. Insulin resistance was determined using homeostasis model assessment (HOMA) score. An intention-to-treat analysis was conducted as the primary analysis using generalised linear models. In addition, per-protocol and dose-response analyses were performed as an exploratory exercise. In total, 32 men (97%) completed the study. Men in the intervention group exercised an average of 4.2 hours/week. Compared to the control group, the exercise group recorded larger improvements in fitness and strength following 12- and 24-weeks of intervention, indicating good levels of adherence. From baseline to 24-weeks, reductions in waist circumference were greater in the exercise group compared with the control group (adjusted intervention effect -4.5 [95% CI -7.5, -1.4] cm; p < 0.01). Reductions in fat mass were also greater in the exercise group than the control group however the difference was non-significant (adjusted intervention effect -1.7 [95% CI -4.9, 1.7] kg; p = 0.32). Compared with controls, the exercise group recorded greater reductions in leptin levels (adjusted intervention effect -3.0 [95% CI -6.4, 0.5] ng/mL; p = 0.09). Changes in gastro-oesophageal reflux symptoms, C-reactive protein, interleukin-6, tumour necrosis factor-a and adiponectin levels did not differ between the groups, however levels of C-reactive protein, insulin and total adiponectin significantly decreased within both groups (p < 0.05). This novel and exploratory exercise trial found beneficial changes in a number of candidate biomarkers associated with oesophageal adenocarcinoma risk in males with Barrett's oesophagus including abdominal obesity, fat mass, leptin, insulin and insulin resistance. These findings, along with those from previous exercise trials in populations with a number of risk factors for breast and colon cancer, suggest that exercise can modulate various metabolic and hormonal pathways implicated in cancer development.

The effect of harvest date on the composition and quality of macadamia nuts

Netiwaranon, Siriwan. — 2007-08-24T18:01:21Z

The effect of heifer dietary protein intake during gestation on fetal and postnatal development of their progeny: attention to the circulatory IGF-axis and the autocrine IGF-axis of skeletal muscle and adipose tissue

Gina Micke — 2011-10-13T00:00:00Z

The beef producing northern pastoral and southern agricultural zones of Australia share an inherent seasonal pattern of pasture quantity and quality. Protein deficiency is a feature of dry season pastures in the northern pastoral zone, whilst protein oversupply is a feature of improved and legume based pastures in the southern agricultural zone. Maternal nutrient intake during gestation has been linked to perturbations to the postnatal growth pathway, the body composition and the metabolism of their progeny. This thesis investigates the effect of heifer (n = 120) protein intake during the first two trimesters of gestation on fetal (n = 71) growth; dystocia and progeny (n = 68) postnatal growth. It also investigates this effect on the circulatory, skeletal muscle and adipose tissue insulin-like growth factor (IGF) axes of the progeny. The study was based at Goondiwindi, Australia (latitude 28.52S, longitude 150.33E) and consisted of a two-by-two factorial design. On the day of artificial insemination (AI), heifers were allocated by stratification by weight and genotype to one of four treatment groups. Treatment groups were defined by the amount of crude protein (CP) fed to each heifer during the first (AI to 93 days of gestation (gd)) and second (94 to 180 gd) trimesters of gestation (HH: first trimester = 1.4 kg CP/d and 76.3 MJ ME/d, second trimester = 1.4 kg CP/d and 82.4 MJ ME; HL: first trimester = 1.4 kg CP/d and 76.3 MJ ME/d, second trimester = 0.4 kg CP/d and 63.1 MJ ME/d; LH: first trimester = 0.4 kg CP/d and 62.5 MJ ME/d, second trimester = 1.4kg CP/d and 82.4 MJ ME/d; LL: first trimester = 0.4kg CP/d and 62.5 MJ ME/d, second trimester = 0.4 kg CP/d and 63.1 MJ ME/d). All heifers were fed 1.06 kg CP/d and 71.45 MJ ME/d from 181 gd until parturition. Progeny remained with their mothers until weaning at 191 days of age (d). From weaning until 401 d they were managed as a single group grazing native pastures at Goondiwindi. From 401 d they were managed as part of a larger group of yearling cattle at Surat, Queensland (27°16′S, 149°07′E) before commencing an intensive feedlot finishing program at 541 d at Dalby, Queensland (27°18′S, 151°26′E). They were commercially slaughtered at 680 d. Heifers fed low compared to high protein diets during the first trimester of gestation had smaller fetuses at 39 gd and progeny with greater expression of IGF-IR mRNA in their SC adipose tissue at 680 d. There were further sex-specific effects of heifer diet during the first trimester of gestation. Male progeny exposed to maternal diets low in protein during the first trimester of gestation were heavier and leaner during the post-weaning period and had greater cross-sectional areas of their semitendinosus and longissimus dorsi muscles when compared to their high protein exposed counterparts. These changes were accompanied by greater IGF-I and IGF-II mRNA expression in their semitendinosus muscle and lower LEP mRNA expression in their PR adipose tissue at 680 d. In contrast, female progeny exposed to maternal diets low in protein during the first trimester of gestation were lighter and of smaller stature during the post-weaning period which resulted in them having lighter carcasses at 680 d. In addition they had greater expression of IGF-IIR mRNA in their semitendinosus muscle but decreased expression of IGF-I mRNA in PR adipose tissue at 680 d when compared to their high protein exposed counterparts. In comparison, heifers fed low protein diets during the second trimester of gestation had lower birthweight calves, an effect that persisted to 29 d, in addition to having calves with greater plasma NEFA concentration at birth than those that were fed high protein diets during the same period. These progeny went on to have greater cross-sectional area of their longissimus dorsi muscle at slaughter; greater expression of IGF-IR mRNA in their semitendinosus muscle, IGF-II mRNA in PR adipose tissue and LEP mRNA in OM adipose tissue, but lesser expression of IGF-IR, IGF-II and IGF-IIR mRNA in their omental adipose tissue at 680 d when compared to their high protein exposed counterparts. A change to maternal diet from high to low protein, or visa versa, at the end of the first trimester of gestation resulted in a male offspring with greater plasma IGF-I concentrations during the postnatal period compared to their counterparts exposed to a constant plane of nutiriton. Importantly, pelvic area measurements obtained prior to conception remained valid in their assessement of the relationship between pelvic area and the likelihood of dystocia occurring in the event of changing maternal nutrient intake during gestation. Heifer protein intake during gestation has a permanent sex-specific effects on: fetal and postnatal growth; the endocrine IGF-axis of progeny; and the autocrine/paracrine IGF-axes of skeletal muscle and adipose tissue of the progeny. These findings may assist cattle producers to optimise both welfare and financial outcomes for the heifer herd.

The effect of infestation with the Australian paralysis tick, Ixodes holocyclus, on thermoregulation and respiration in the dog

Fearnley, C. E. A. (Cecily E. A.) — 2008-11-21T00:00:00Z

The effect of intra-muscular components of oxidative phosphorylation on the rate of phosphocreatine resynthesis following intense exercise

McMahon, Shaun A.J. — 2010-10-29T00:00:00Z

The Effect of Mental Workload on Decision Making in Air Traffic Control

Selina Fothergill — 2010-08-23T00:00:00Z

The aim of the present research was to examine the impact of mental workload on conflict resolution decision making in air traffic control (ATC). While previous studies have examined the effect of workload on performance (Averty, 2004; Kopardekar & Magyrits, 2002) and conflict detection (Mogford, 1997; Seamster, Redding, Cannon, Ryder & Purcell, 1993), limited research examines the effect of workload on conflict resolution decisions. The aim of the first study was to gain an initial understanding of how controllers manage their airspace. Results demonstrated that controllers scan repetitively, in a clockwise and top-bottom pattern; group aircraft with similar characteristics and use at least five lateral and eight vertical conflict resolution heuristics. Study two examined the effect of conflict type on conflict resolution under different levels of workload. Under moderate workload controllers used a mix of solutions, while under high workload, solutions became more conservative. Study three examined the effect of other contextual factors on conflict resolution. Results again suggested conflict type affects conflict resolution decisions and also that other contextual parameters, such as aircraft performance may play a role in solution preferences. Study four examined the effect of workload on conflict resolution using a realistic ATC task. Workload not only impacted on controllers’ performance scores, but interacted with conflict type to determine whether an efficient solution was preferred over a less efficient solution. This research identifies some of the heuristics experts use when competing priorities are present and provides an understanding of how conflict type, contextual factors and workload affect decisions. Findings contribute to the naturalistic decision making (NDM) literature by demonstrating how the situation can influence decision making.