Showing papers by "University of Wollongong published in 2012"

The 27–year decline of coral cover on the Great Barrier Reef and its causes

Abstract: The world’s coral reefs are being degraded, and the need to reduce local pressures to offset the effects of increasing global pressures is now widely recognized. This study investigates the spatial and temporal dynamics of coral cover, identifies the main drivers of coral mortality, and quantifies the rates of potential recovery of the Great Barrier Reef. Based on the world’s most extensive time series data on reef condition (2,258 surveys of 214 reefs over 1985–2012), we show a major decline in coral cover from 28.0% to 13.8% (0.53% y−1), a loss of 50.7% of initial coral cover. Tropical cyclones, coral predation by crown-of-thorns starfish (COTS), and coral bleaching accounted for 48%, 42%, and 10% of the respective estimated losses, amounting to 3.38% y−1 mortality rate. Importantly, the relatively pristine northern region showed no overall decline. The estimated rate of increase in coral cover in the absence of cyclones, COTS, and bleaching was 2.85% y−1, demonstrating substantial capacity for recovery of reefs. In the absence of COTS, coral cover would increase at 0.89% y−1, despite ongoing losses due to cyclones and bleaching. Thus, reducing COTS populations, by improving water quality and developing alternative control measures, could prevent further coral decline and improve the outlook for the Great Barrier Reef. Such strategies can, however, only be successful if climatic conditions are stabilized, as losses due to bleaching and cyclones will otherwise increase.

A leavening strategy to prepare reduced graphene oxide foams.

Abstract: For instance, freestanding graphene macroscopic structures have shown unique catalytic, electrochemical, and mechanical properties together with potential applications in chemical fi lters and electrodes for energy storage devices. [ 6–8 , 11 , 30 ] However, in most cases, during the process of assembling nanometerscale building blocks into macroscopic paper-like structures, the large accessible surface area of 2D graphene sheets is lost. The reason for this is that the individual graphene sheets tend to irreversibly aggregate and restack owing to the strong π π stacking and van der Waals force between the planar basal planes of graphene sheets. This reduces the potential applications of graphene materials in electrochemical electrodes, composite materials, and so on. [ 20 ] Therefore, preventing aggregation of graphene sheets in the macroscopic structures, such that the properties of the individual graphene sheets are not compromised, is a critical challenge in constructing functional graphene-based macroscopic structures. Currently, a number of strategies for preventing aggregation have been developed, which include adding spacers (e.g., surfactants, nanoparticles, polymers), [ 27–36 ] template-assisted growth, [ 37 ] and crumpling the graphene sheets. [ 18 , 38 ] Alternatively, several groups have reported the formation of freestanding 3D graphene-based macroscopic structures without the assistance of any spacers or templates. [ 7 , 39,40 ] For instance, Li and coworkers reported the preparation of freestanding multilayered graphene fi lms by vacuum-assisted fi ltration based on the effective prevention of graphene intersheet restacking. [ 7 ] Shi and coworkers demonstrated the formation of a 3D graphene hydrogel by a hydrothermal method. [ 39 ] However, preparing freestanding and fl exible graphene fi lms with large accessible surface area but

Confining Sulfur in Double-Shelled Hollow Carbon Spheres for Lithium-Sulfur Batteries

Abstract: New sulfur—carbon nanocomposites are prepared by confining sulfur in double-shelled hollow carbon spheres, which are obtained from SnO2 hollow spheres dispersed in aqueous glucose solution (autoclave, 180 °C, 4 h).

Facile Oxygen Reduction on a Three‐Dimensionally Ordered Macroporous Graphitic C3N4/Carbon Composite Electrocatalyst

Abstract: Honeycomb catalysis: a facile oxygen reduction reaction has been observed on a graphitic C(3)N(4)/carbon catalyst with three-dimensional interconnected macropores (see picture with SiO(2) template). This material not only shows catalytic activity that is comparable to that of commercial Pt/C, but also has much higher organic-fuel tolerance and long-term stability.

semPLS: Structural Equation Modeling Using Partial Least Squares

Abstract: Structural equation models (SEM) are very popular in many disciplines. The partial least squares (PLS) approach to SEM offers an alternative to covariance-based SEM, which is especially suited for situations when data is not normally distributed. PLS path modelling is referred to as soft-modeling-technique with minimum demands regarding mea- surement scales, sample sizes and residual distributions. The semPLS package provides the capability to estimate PLS path models within the R programming environment. Different setups for the estimation of factor scores can be used. Furthermore it contains modular methods for computation of bootstrap confidence intervals, model parameters and several quality indices. Various plot functions help to evaluate the model. The well known mobile phone dataset from marketing research is used to demonstrate the features of the package.

Preparation and characterization of spinel Li4Ti5O12 nanoparticles anode materials for lithium ion battery

Abstract: Spinel Li4Ti5O12 nanoparticles were prepared via a high-temperature solid-state reaction by adding the prepared cellulose to an aqueous dispersion of lithium salts and titanium dioxide. The precursors of Li4Ti5O12 were characterized by thermogravimetry and differential scanning calorimetry. The obtained Li4Ti5O12 nanoparticles were characterized using X-ray diffraction, transmission electron microscopy (TEM) and electrochemical measurements. The TEM revealed that the Li4Ti5O12 prepared with cellulose is composed of nanoparticles with an average particle diameter of 20–30 nm. Galvanostatic battery testing showed that nano-sized Li4Ti5O12 exhibit better electrochemical properties than submicro-sized Li4Ti5O12 do especially at high current rates, which can deliver a reversible discharge capacity of 131 mAh g−1 at the rate of 10 C, whereas that of the submicro-sized sample decreases to 25 mAh g−1 at the same rate (10 C). Its reversible capacity is maintained at ~172.2 mAh g−1 with the voltage range 1.0–3.0 V (vs. Li) at the current rate of 0.5 C for over 80 cycles.

Review: Recent progress on programming methods for industrial robots

Abstract: Although an automated flexible production cell is an intriguing prospect for small to median enterprises (SMEs) in current global market conditions, the complexity of programming remains one of the major hurdles preventing automation using industrial robots for SMEs. This paper provides a comprehensive review of the recent research progresses on the programming methods for industrial robots, including online programming, offline programming (OLP), and programming using Augmented Reality (AR). With the development of more powerful 3D CAD/PLM software, computer vision, sensor technology, etc. new programming methods suitable for SMEs are expected to grow in years to come.

The first climate refugees? Contesting global narratives of climate change in Tuvalu

Abstract: Climate change effects such as sea-level rise are almost certain. What these outcomes mean for different populations, however, is far less certain. Climate change is both a narrative and material phenomenon. In so being, understanding climate change requires broad conceptualisations that incorporate multiple voices and recognise the agency of vulnerable populations. In climate change discourse, climate mobility is often characterised as the production of ‘refugees’, with a tendency to discount long histories of ordinary mobility among affected populations. The case of Tuvalu in the Pacific juxtaposes migration as everyday practice with climate refugee narratives. This climate-exposed population is being problematically positioned to speak for an entire planet under threat. Tuvaluans are being used as the immediate evidence of displacement that the climate change crisis narrative seems to require. Those identified as imminent climate refugees are being held up like ventriloquists to present a particular (western) ‘crisis of nature’. Yet Tuvaluan conceptions of climate challenges and mobility practices show that more inclusive sets of concepts and tools are needed to equitably and effectively approach and characterise population mobility.

BiVO(4)/CeO(2) nanocomposites with high visible-light-induced photocatalytic activity.

Abstract: Preparation of bismuth vanadate and cerium dioxide (BiVO4/CeO2) nanocomposites as visible-light photocatalysts was successfully obtained by coupling a homogeneous precipitation method with hydrothermal techniques. The BiVO4/CeO2 nanocomposites with different mole ratios were synthesized and characterized by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). Absorption range and band gap energy, which are responsible for the observed photocatalyst behavior, were investigated by UV–vis diffuse reflectance (UV–vis DR) spectroscopy. Photocatalytic activities of the prepared samples were examined by studying the degradation of model dyes Methylene Blue, Methyl Orange, and a mixture of Methylene Blue and Methyl Orange solutions under visible-light irradiation (>400 nm). Results clearly show that the BiVO4/CeO2 nanocomposite in a 0.6:0.4 mol ratio exhibited the highest photocatalytic activity in dye wastewater treatment.

Synergistic toughening of composite fibres by self-alignment of reduced graphene oxide and carbon nanotubes.

Abstract: The extraordinary properties of graphene and carbon nanotubes motivate the development of methods for their use in producing continuous, strong, tough fibres. Previous work has shown that the toughness of the carbon nanotube-reinforced polymer fibres exceeds that of previously known materials. Here we show that further increased toughness results from combining carbon nanotubes and reduced graphene oxide flakes in solution-spun polymer fibres. The gravimetric toughness approaches 1,000 J g(-1), far exceeding spider dragline silk (165 J g(-1)) and Kevlar (78 J g(-1)). This toughness enhancement is consistent with the observed formation of an interconnected network of partially aligned reduced graphene oxide flakes and carbon nanotubes during solution spinning, which act to deflect cracks and allow energy-consuming polymer deformation. Toughness is sensitive to the volume ratio of the reduced graphene oxide flakes to the carbon nanotubes in the spinning solution and the degree of graphene oxidation. The hybrid fibres were sewable and weavable, and could be shaped into high-modulus helical springs.

Distribution System Planning With Incorporating DG Reactive Capability and System Uncertainties

Abstract: Distributed generation (DG) systems are considered an integral part in future distribution system planning. The active and reactive power injections from DG units, typically installed close to the load centers, are seen as a cost-effective solution for distribution system voltage support, energy saving, and reliability improvement. This paper proposes a novel distribution system expansion planning strategy encompassing renewable DG systems with schedulable and intermittent power generation patterns. The reactive capability limits of different renewable DG systems covering wind, solar photovoltaic, and biomass-based generation units are included in the planning model and the system uncertainties such as load demand, wind speed, and solar radiation are also accounted using probabilistic models. The problem of distribution system planning with renewable DG is formulated as constrained mixed integer nonlinear programming, wherein the total cost will be minimized with optimal allocation of various renewable DG systems. A solution algorithm integrating TRIBE particle swarm optimization (TRIBE PSO) and ordinal optimization (OO) is developed to effectively obtain optimal and near-optimal solutions for system planners. TRIBE PSO, OO, and the proposed algorithm are applied to a practical test system and results are compared and presented.

Auditory Hallucinations in Schizophrenia and Nonschizophrenia Populations: A Review and Integrated Model of Cognitive Mechanisms

Abstract: While the majority of cognitive studies on auditory hallucinations (AHs) have been conducted in schizophrenia (SZ), an increasing number of researchers are turning their attention to different clinical and nonclinical populations, often using SZ findings as a model for research. Recent advances derived from SZ studies can therefore be utilized to make substantial progress on AH research in other groups. The objectives of this article were to (1) present an up-to-date review regarding the cognitive mechanisms of AHs in SZ, (2) review findings from cognitive research conducted in other clinical and nonclinical groups, and (3) integrate these recent findings into a cohesive framework. First, SZ studies show that the cognitive underpinnings of AHs include self-source-monitoring deficits and executive and inhibitory control dysfunctions as well as distortions in top-down mechanisms, perceptual and linguistic processes, and emotional factors. Second, consistent with SZ studies, findings in other population groups point to the role of top-down processing, abnormalities in executive inhibition, and negative emotions. Finally, we put forward an integrated model of AHs that incorporates the above findings. We suggest that AHs arise from an interaction between abnormal neural activation patterns that produce salient auditory signals and top-down mechanisms that include signal detection errors, executive and inhibition deficits, a tapestry of expectations and memories, and state characteristics that influence how these experiences are interpreted. Emotional factors play a particular prominent role at all levels of this hierarchy. Our model is distinctively powerful in explaining a range of phenomenological characteristics of AH across a spectrum of disorders.

Foucault, Power, and Education

Abstract: © 2013 Taylor & Francis. Foucault, Power, and Education invites internationally renowned scholar Stephen J. Ball to reflect on the importance and influence of Foucault on his work in educational policy. By focusing on some of the ways Foucault has been placed in relation to educational questions or questions about education, Ball highlights the relationships between Foucault’s concepts and methods, and educational research and analysis. An introductory chapter offers a brief explanation of some of Foucault’s key concerns, while additional chapters explore ways in which Ball himself has sought to apply Foucault’s ideas in addressing contemporary educational issues.In this intensely personal and reflective text, Ball offers an interpretation of his Foucault—That is, his own particular reading of the Foucauldian toolbox. Ideal for courses in education policy and education studies, this valuable teaching resource is essential reading for any education scholar looking for a starting point into the literature and ideas of Foucault.

Implementing Web 2.0 technologies in higher education: A collective case study

Abstract: Web 2.0 technologies are becoming more popular in the everyday lives of students. As a result, teachers and designers have begun to explore their use in formal education. This paper presents evaluation findings from a collective case study of six Web 2.0 implementations in Australian higher education. The research was undertaken as part of a larger study that sought to understand how today's students use information and communication technologies to support their learning. Conducted across three universities, the research included a range of disciplines, class sizes and year levels. A common evaluation strategy was used in order to collect comparable data from which commonalities and differences could be identified. This paper provides an overview of the study, describes the methodology used, summarises the implementation experiences of staff and students involved and presents the key findings. The results suggest that most students had little prior experience with relevant technologies and that many struggled to see the value of using Web 2.0 technologies for learning and teaching, both of which have important implications for the design of appropriate learning tasks. While the argument can be made for improving the design through better task-technology alignment, this study also highlights inherent tensions between Web 2.0 and educational practices.

Antarctic Climate Change and the Environment: an Update.

Abstract: We present an update of the ‘key points’ from the Antarctic Climate Change and the Environment (ACCE) report that was published by the Scientific Committee on Antarctic Research (SCAR) in 2009. We summarise subsequent advances in knowledge concerning how the climates of the Antarctic and Southern Ocean have changed in the past, how they might change in the future, and examine the associated impacts on the marine and terrestrial biota. We also incorporate relevant material presented by SCAR to the Antarctic Treaty Consultative Meetings, and make use of emerging results that will form part of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report

Host–pathogen checkpoints and population bottlenecks in persistent and intracellular uropathogenic Escherichia coli bladder infection

Abstract: Bladder infections affect millions of people yearly, and recurrent symptomatic infections (cystitis) are very common. The rapid increase in infections caused by multidrug-resistant uropathogens threatens to make recurrent cystitis an increasingly troubling public health concern. Uropathogenic Escherichia coli (UPEC) cause the vast majority of bladder infections. Upon entry into the lower urinary tract, UPEC face obstacles to colonization that constitute population bottlenecks, reducing diversity, and selecting for fit clones. A critical mucosal barrier to bladder infection is the epithelium (urothelium). UPEC bypass this barrier when they invade urothelial cells and form intracellular bacterial communities (IBCs), a process which requires type 1 pili. IBCs are transient in nature, occurring primarily during acute infection. Chronic bladder infection is common and can be either latent, in the form of the quiescent intracellular reservoir (QIR), or active, in the form of asymptomatic bacteriuria (ASB/ABU) or chronic cystitis. In mice, the fate of bladder infection, QIR, ASB, or chronic cystitis, is determined within the first 24 h of infection and constitutes a putative host–pathogen mucosal checkpoint that contributes to susceptibility to recurrent cystitis. Knowledge of these checkpoints and bottlenecks is critical for our understanding of bladder infection and efforts to devise novel therapeutic strategies.

A “skeleton/skin” strategy for preparing ultrathin free-standing single-walled carbon nanotube/polyaniline films for high performance supercapacitor electrodes

Abstract: One of the most critical aspects in the preparation of single-walled carbon nanotubes (SWCNTs)/conducting polymer hybrid electrodes is to improve the energy density without seriously deteriorating their high power capability. Here, we report a “skeleton/skin” strategy for the preparation of free-standing, thin and flexible SWCNT/polyaniline (PANI) hybrid films by a simple in situ electrochemical polymerization method using directly grown SWCNT films with a continuous reticulate structure as template. In situ electrochemical polymerization can achieve effective deposition of PANI onto the surface of SWCNT bundles in the films and control the morphology and microstructure of the SWCNT/PANI hybrid films. In a SWCNT/PANI hybrid film, the directly grown SWCNT film with continuous reticulate architecture acts as the skeleton and PANI layers act as the skin. This unique continuous “skeleton/skin” structure ensures that these hybrid films have much higher conductivity compared to SWCNT/PANI composite films based on post-deposition SWCNT films. Flexible supercapacitors have been fabricated using the SWCNT/PANI hybrid films as both electrodes and charge collectors without metallic current collectors. High energy and power densities (131 W h kg−1 and 62.5 kW kg−1, respectively) have been achieved for the optimized assembly. The high electrical conductivity and flexibility, in combination with continuous porous architecture, suggests that the as-prepared ultrathin free-standing SWCNT/PANI hybrid films have significant potential as promising electrode materials for thin, lightweight and flexible energy storage devices with high performance.

Process-evaluation of tropospheric humidity simulated by general circulation models using water vapor isotopologues: 1. Comparison between models and observations

Abstract: The goal of this study is to determine how H2O and HDO measurements in water vapor can be used to detect and diagnose biases in the representation of processes controlling tropospheric humidity in atmospheric general circulation models (GCMs). We analyze a large number of isotopic data sets (four satellite, sixteen ground-based remote-sensing, five surface in situ and three aircraft data sets) that are sensitive to different altitudes throughout the free troposphere. Despite significant differences between data sets, we identify some observed HDO/H2O characteristics that are robust across data sets and that can be used to evaluate models. We evaluate the isotopic GCM LMDZ, accounting for the effects of spatiotemporal sampling and instrument sensitivity. We find that LMDZ reproduces the spatial patterns in the lower and mid troposphere remarkably well. However, it underestimates the amplitude of seasonal variations in isotopic composition at all levels in the subtropics and in midlatitudes, and this bias is consistent across all data sets. LMDZ also underestimates the observed meridional isotopic gradient and the contrast between dry and convective tropical regions compared to satellite data sets. Comparison with six other isotope-enabled GCMs from the SWING2 project shows that biases exhibited by LMDZ are common to all models. The SWING2 GCMs show a very large spread in isotopic behavior that is not obviously related to that of humidity, suggesting water vapor isotopic measurements could be used to expose model shortcomings. In a companion paper, the isotopic differences between models are interpreted in terms of biases in the representation of processes controlling humidity. Copyright © 2012 by the American Geophysical Union.

Prevalence and Correlates of Low Fundamental Movement Skill Competency in Children

Abstract: OBJECTIVE: To describe the demographic and health-related characteristics of school-aged children with low competency in fundamental movement skills (FMS). METHODS: Cross-sectional representative school-based survey of Australian elementary and high school students ( n = 6917) conducted in 2010. Trained field staff measured students’ height, weight, and assessed FMS and cardiorespiratory endurance (fitness). Information on students’ demographics and physical activity was collected by questionnaire. RESULTS: Overall, the prevalence of students with low motor skill competency was high. Girls with low socioeconomic status (SES) were twice as likely to be less competent in locomotor skills compared with high SES peers. Among boys, there was a strong association between low competency in FMS and the likelihood of being from non–English-speaking cultural backgrounds. There was a clear and consistent association between low competency in FMS and inadequate cardiorespiratory fitness. For boys, there was a clear association between low competency in object-control skills and not meeting physical activity recommendations. Conversely, the odds of being inactive were double among girls who had low competency in locomotor skills. CONCLUSIONS: Low competency in FMS is strongly associated with lower cardiorespiratory fitness and physical activity levels in children and adolescents. The characteristics of students with competency in FMS differ by gender and skills types and show that interventions need to target girls from low SES backgrounds and boys from non–English-speaking cultural backgrounds. The high prevalence of low competency in FMS among Grade 4 students indicates that FMS interventions need to start during the preschool and early school years. * Abbreviations: CI — : confidence interval FMS — : fundamental movement skills NSW — : New South Wales OR — : odds ratio SES — : socioeconomic status

A Review of Localization Systems for Robotic Endoscopic Capsules

Abstract: Obscure gastrointestinal (GI) bleeding, Crohn disease, Celiac disease, small bower tumors, and other disorders that occur in the GI tract have always been challenging to be diagnosed and treated due to the inevitable difficulty in accessing such a complex environment within the human body. With the invention of wireless capsule endoscope, the next generation of the traditional cabled endoscope, not only a dream has come true for the patients who have experienced a great discomfort and unpleasantness caused by the conventional endoscopic method, but also a new research field has been opened to develop a complete miniature robotic device that is swallowable and has full functions of diagnosis and treatment of the GI diseases. However, such an ideal device needs to be equipped with a highly accurate localization system to be able to exactly determine the location of lesions in the GI tract and provide essential feedback to an actuation mechanism controlling the device's movement. This paper presents a comprehensive overview of the localization systems for robotic endoscopic capsules, for which the motivation, challenges, and possible solutions of the proposed localization methods are also discussed.