A soil-free plant growth system to facilitate analysis of plant pathogen interactions in roots

Analysis of the interaction of pathogens with plant roots is often complicated by the growth of plants in a soil substrate. A soil-free plant growth system (SPS) was developed that removes the need for a substrate while supporting the growth of seedlings in a nutrient rich, oxygenated environment. The model legume Lupinus angustifolius was used to compare the growth of seedlings within soil and the SPS. Seedlings grown under both conditions were similar in morphology, anatomy and health (measured by leaf chlorophyll abundance) and importantly there was little difference in root growth and development although straighter and fuller root systems were achieved in the SPS. The ease of access to the root system proved efficient for the analysis of root and pathogen interactions with no interference from soil or adhering particulate matter. Following inoculation of L. angustifolius roots with Phytophthora cinnamomi the host/pathogen interaction was easily observed and tissues sampled undamaged.

A nonparametric model of financial system and economic growth

In this paper, we show that in the proposed models for economic growth, the financial system variables are generally nonparametric. We, thus, use a nonparametric panel data model to estimate the financial system-economic growth relationship. Our results suggest that as long as a country's domestic credit and private credit are above their cross-sectional mean they have a positive effect on GDP growth. We also discover that market capitalisation positively and significantly impacts GDP growth, while stocks traded (with the exception of OECD countries) has a statistically insignificant effect on GDP growth.

Growth of Australian shortfin eel (Anguilla Australis) elvers given different dietary protein and lipid levels

The Australian shortfin eel, Anguilla australis is a potential candidate for intensive aquaculture. The present study was undertaken to evaluate the growth of elvers (5.4 g ± 0.1 initial weight) fed with diets of varying protein and lipid content, and to assess the potential of using soya-bean meal as a dietary ingredient. A 10 week experiment was conducted at 24 (±1.0) °C by rearing fish, in 60 L conical fibre glass tanks using a closed recirculation system. Diets having protein concentrations of 40 or 50% (by dry weight) were tested at three lipid levels (15, 20, 25%); diets being designated P₄₀L₁₅, P₄₀L₂₀, P₄₀L₂₅, P₅₀L₁₅, etc. All these diets contained 5% soya-bean meal. In addition P₅₀L₂₀ diets were formulated to contain 10 and 20% soya-bean meal in the diet (Diets S1 & S2). Shortfin eel grew best on the P₅₀L₁₅ diet, with an average specific growth rate of 2.26%. Food conservation ratio (FCR) and Protein efficiency ratio (PER) ranged from 1.21 (P₅₀L₁₅) to 2.12 (P₄₀L₂₅), and 0.92 (P₅₀L₂₅) to 1.65 (P₅₀L₁₅), respectively. Based on all criteria the best growth performance of shortfin eel was on the P₅₀L₁₅ diet, followed by P₄₀L₂₀ and P₄₀L₁₅. At both protein levels fish reared on diets with 25% lipid performed poorly. The performance of shortfin eel was not affected by the amount of soya-bean meal in the diet, up to a maximum of 20% dietary inclusion. No significant differences in muscle protein were evident in shortfin eel reared on different dietary treatments, nor was the lipid content of muscle related to dietary lipid level.

The indigenous art market: a roadmap to a more equitable and efficient system

The Indigenous art market plays a significant role both in promoting appreciation for the accomplishments of Aboriginal culture and within broader concepts of the export of a national culture.[1] Despite the growth in status and impact of Indigenous art over the past decade, very little scholarship or resources exist to assist their development and analyse their impact on economic or social wellbeing. This paper canvasses new ways of operating the Indigenous art market to better support emerging and established artists in a globalised economy and suggests that there is a pressing need for future research to develop a new framework for its operation.

Economic growth and sustainability - an empirical study of the Thai development experience

Increasing economic growth has long been the dominant position within the public policies of all South East Asian countries. More recently, a new issue, sustainability, has emerged within development economic literature, which has significant implications for the continual pursuit of economic growth. Sustainability is concerned with ensuring the current generation meets their present needs without threatening future generations' ability to do likewise. This ability is dependent on a healthy and functioning socio-economic environmental (SEE) system. Economic growth can damage the SEE-system, though, through resource degradation, over-harvesting and pollution. Therefore, achieving economic growth and sustainability simultaneously may not be possible. This paper discusses these tensions between economic growth and sustainability by undertaking a number of SEE-based adjustments to GDP in order to measure sustainability. Thailand is used as a case study for a 25 year period, 1975-1999. The adjustments include the environmental costs caused by economic growth such as noise pollution, water pollution, the depletion of non-renewable resources, and deforestation. The results show a stark difference in terms of GDP per capita and the SEE-adjusted GDP per capita figure. The paper concludes that with increasing environmental costs of economic growth, pursuing high growth objectives without considerations to the environment threatens sustainability

Institutions and policies for growth and poverty reduction: the role of private sector development

This paper goes over some of the recent discussions on the effects on growth and poverty of institutions and policies, especially those that relate to the functioning of the private sector. It examines the empirical relationship between various measures of institutional quality and regulatory policies, and economic growth and poverty. The results suggest that good governance, as measured by a strong commitment to the rule of law, among other things, matters for poverty reduction largely through its effect on economic growth. In terms of business regulations, the paper finds that less restrictive regulations pertaining to starting a business are associated with higher economic growth as well as lower rates of $2-a-day poverty. Political freedom is not associated with either higher growth or lower poverty. Taken together, the evidence here seems to suggest that the delivery of good governance and policies that facilitate the creation of new enterprises are more relevant for growth and poverty reduction than the nature of the political system per se.

The problem of obesity : is there a role for antagonists of the renin-angiotensin system?

Obesity is a major health problem worldwide; it is associated with more than 30 medical conditions and is a leading cause of unnecessary deaths. Adipose tissue not only acts as an energy store, but also behaves like an endocrine organ, synthesising and secreting numerous hormones and cytokines. Angiotensin II (ANG II) is the biologically active component of the renin-angiotensin system (RAS). The RAS is present in adipose tissue and evidence suggests that ANG II is intimately linked to obesity. Indeed, ANG II increases fat cell growth and differentiation, increases synthesis, uptake and storage of fatty acids and triglycerides and possibly inhibits lipolysis. Evidence obtained using genetically modified animals has shown that the amount of body fat is directly related to the amount of ANG II, i.e., animals with low levels of ANG II have reduced fat stores while animals with excessive ANG II have increased fat stores. In humans, epidemiological evidence has shown that body fat is correlated with angiotensinogen, a precursor of ANG II, or other components of the RAS. Furthermore, blocking the production and/or actions of ANG II with drugs or natural substances decreases body fat. The decrease in body fat caused by such treatments predominantly occurs in abdominal fat depots and appears to be independent of energy intake and digestibility. Clearly, ANG II has an important role in the accumulation of body fat and the possibility exists that treatment of obesity will be enhanced by the use of natural or synthetic substances that interfere with ANG II.

Focused ion beam milling as a universal template technique for patterned growth of carbon nanotubes

Focused ion beam (FIB) milling system has been used to create nanosized patterns as the template for patterned growth of carbon nanotubes on Si substrate surface without predeposition of metal catalysts. Carbon nanotubes only nucleate and grow on the template under controlled pyrolysis of iron phthalocyanine at 1000 °C. The size, growth direction, and density of the patterned nanotubes can be controlled under different growth conditions and template sizes. Atomic force microscopy and electron microscopy analyses reveal that the selective growth on the FIB template is due to its special surface morphology and crystalline structure.

Growth and structure of prismatic boron nitride nanorods

Prismatic boron nitride nanorods have been grown on single crystal silicon substrates by mechanical ball-milling followed by annealing at 1300 °C. Growth takes place by rapid surface diffusion of BN molecules, and follows heterogeneous nucleation at catalytic particles of an Fe/Si alloy. Lattice imaging transmission electron microscopy studies reveal a central axial row of rather small truncated pyramidal nanovoids on each nanorod, surrounded by three basal planar BN domains which, with successive deposition of epitaxial layers adapt to the void geometry by crystallographic faceting. The bulk strain in the nanorods is taken up by the presence of what appear to be simple nanostacking faults in the external, near-surface domains which, like the nanovoids are regularly repetitive along the nanorod length. Growth terminates with a clear cuneiform tip for each nanorod. Lateral nanorod dimensions are essentially determined by the size of the catalytic particle, which remains as a foundation essentially responsible for base growth. Growth, structure, and dominating facets are shown to be consistent with a system which seeks lowest bulk and surface energies according to the well-known thermodynamics of the capillarity of solids.

Growth and diversity in doctoral education : assessing the Australian experience

The major growth of doctoral education in recent decades has attracted attention from policy makers and researchers. In this article we explore the growth of doctoral education in Australia, its impact on diversity in respect of the doctoral population, shifts in disciplinary strengths, institutional concentration and award programs. We conclude that there has been both change and continuity in the provision of doctoral education with extensive variation at the level of practice in what is a reasonably stable system featuring continuing hierarchical institutional diversification. The limitations of available data and issues for further research, policy and practice are discussed.

Design and analysis of hull configurations for a low-cost, autonomous underwater robot as an enabling technology for system of system applications

The objective of this research is to model and analyze candidate hull configurations for a low-cost, modular, autonomous underwater robot. As the computational power and speed of microprocessors continue to progress, we are seeing a growth in the research, development, and the utilization of underwater robots. The number of applications is broadening in the R&D and science communities, especially in the area of multiple, collaborative robots. These underwater collaborative robots represent an instantiation of a System of Systems (SoS). While each new researcher explores a unique application, control method, etc. a new underwater robot vehicle is designed, developed, and deployed. This sometimes leads to one-off designs that are costly. One limit to the wide-scale utilization of underwater robotics is the cost of development. Another limit is the ability to modify the configuration for new applications and evolving requirements. Consequently, we are exploring autonomous underwater vehicle (AUV) hull designs towards the goal of modularity, vehicle dexterity, and minimizing the cost. In our analysis, we have employed 3D solid modeling tools and finite element methods. In this paper we present our initial results and discuss ongoing work.

Development and use of a model system to monitor clubroot disease progression with an Australian field collection of Plasmodiophora brassicae

A modified sand–liquid culture method facilitated easy visualisation of the primary life cycle stages of Plasmodiophora brassicae within clean root hairs of the Arabidopsis host. Pathogen penetration occurred from day 4 onwards and then primary plasmodia developed within the host root. Several Arabidopsis ecotypes tested in varying growth conditions showed differences in disease expression. Defined growth cabinet conditions were found most suitable for studying disease progression in the ecotypes and for achieving uniform infection and disease development. Arabidopsis ecotypes Ta-0 and Tsu-0 known to be partially resistant to a German single-spore isolate of P. brassicae were susceptible to an Australian (Victorian) field population of P. brassicae. The European clubroot differential test was used to confirm virulence and describe the pathotype of the Victorian field population. Knowledge of the interaction of an Australian population of P. brassicae with its host will provide valuable information on a disease which is very difficult to control.

Role of exercise in the development of bone strength during growth

Exercise during growth may increase peak bone mass; if the benefits are maintained it may reduce the risk of fracture later in life (1). It is hypothesised that exercise will preferentially enhance bone formation on the surface of cortical bone that is undergoing bone modeling at the time (2). Therefore, exercise may increase bone mass accrual on the outer periosteal surface during the pre- and peri-pubertal years, and on the inner endocortical surface during puberty (3). An increase in bone formation on the periosteal surface is, however, more effective for increasing bone strength than medullary contraction (4). While exercise may have a role in osteoporosis prevention, there is little evidential basis to support this notion. It is generally accepted that weight-bearing exercise is important, but it is not known how much, how often, what magnitude or how long children need to exercise before a clinically important increase in bone density is obtained. In this thesis, the effect of exercise on the growing skeleton is investigated in two projects. The first quantifies the magnitude and number of loads associated with and in a moderate and low impact exercise program and non-structured play. The second project examines how exercise affects bone size and shape during different stages of growth. Study One: The Assessment of the Magnitude of Exercise Loading and the Skeletal Response in Girls Questions: 1) Does moderate impact exercise lead to a greater increase in BMC than low impact exercise? 2) Does loading history influence the osteogenic response to moderate impact exercise? 3) What is the magnitude and number of loads that are associated with a moderate and low impact exercise program? Methods: Sixty-eight pre-and early-pubertal girls (aged 8.9±0.2 years) were randomised to either a moderate or low impact exercise regime for 8.5-months. In each exercise group the girls received either calcium fortified (-2000 mg/week) or non-fortified foods for the duration of the study. The magnitude and number of loads associated with the exercise programs and non-structured play were assessed using a Pedar in-sole mobile system and video footage, respectively. Findings: After adjusting for baseline BMC, change in length and calcium intake, the girls in the moderate exercise intervention showed greater increases in BMC at the tibia (2.7%) and total body (1.3%) (p ≤0.05). Girl's who participated in moderate impact sports outside of school, showed greater gains in BMC in response to the moderate impact exercise program compared to the low impact exercise program (2.5 to 4.5%, p ≤0.06 to 0.01). The moderate exercise program included -400 impacts per class, that were applied in a dynamic manner and the magnitude of impact was up to 4 times body weight. Conclusion: Moderate-impact exercise may be sufficient to enhance BMC accrual during the pre-pubertal years. However, loading history is likely to influence the osteogenic response to additional moderate impact exercise. These findings contribute towards the development of school-based exercise programs aimed at improving bone health of children. Study Two: Exercise Effect on Cortical Bone Morphology During Different Stages of Maturation in Tennis Players Questions: 1) How does exercise affect bone mass (BMC) bone geometry and bone strength during different stages of growth? 2) Is there an optimal stage during growth when exercise has the greatest affect on bone strength? Methods: MRI was used to measure average total bone, cortical and medullary areas at the mid- and distal-regions of the playing and non-playing humerii in 47 pre-, peri- and post-pubertal competitive female tennis players aged 8 to 17 years. To assess bone rigidity, each image was imported into Scion Image 4.0.2 and the maximum, minimum and polar second moments of area were calculated using a custom macro. DXA was used to measure BMC of the whole humerus. Longitudinal data was collected on 37 of the original cohort. Findings: Analysis of the entire cohort showed that exercise was associated with increased BMC and cortical area (8 to 14%), and bone rigidity (11 to 23%) (all p ≤0.05). The increase in cortical bone area was associated with periosteal expansion in the pre-pubertal years and endocortical contraction in the post-pubertal years (p ≤0.05). The exercise-related gains in bone mass that were accrued at the periosteum during the pre-pubertal years, did not increase with advanced maturation and/or additional training. Conclusion: Exercise increased cortical BMC by enhancing bone formation on the periosteal surface during the pre-pubertal years and on the endocortical surface in the post-pubertal years. However, bone strength only increased in response to bone acquisition on the periosteal surface. Therefore the pre-pubertal years appear to be the most opportune time for exercise to enhance BMC accrual and bone strength