Vleeshouwers V.G.A.A.,Wageningen University |
Oliver R.P.,Curtin University Australia
Molecular Plant-Microbe Interactions | Year: 2014
One of most important challenges in plant breeding is improving resistance to the plethora of pathogens that threaten our crops. The ever-growing world population, changing pathogen populations, and fungicide resistance issues have increased the urgency of this task. In addition to a vital inflow of novel resistance sources into breeding programs, the functional characterization and deployment of resistance also needs improvement. Therefore, plant breeders need to adopt new strategies and techniques. In modern resistance breeding, effectors are emerging as tools to accelerate and improve the identification, functional characterization, and deployment of resistance genes. Since genome-wide catalogues of effectors have become available for various pathogens, including biotrophs as well as necrotrophs, effector-assisted breeding has been shown to be successful for various crops. "Effectoromics" has contributed to classical resistance breeding as well as for genetically modified approaches. Here, we present an overview of how effector-assisted breeding and deployment is being exploited for various pathosystems. © 2014 The American Phytopathological Society.
Soria R.,Curtin University Australia
Monthly Notices of the Royal Astronomical Society | Year: 2013
We compare the outer radius of the accretion disc in the intermediate-mass black hole candidate HLX-1 as estimated from the ultraviolet/optical continuum, with the values estimated from its outburst decline time-scales. We fit the Swift 2010 outburst decline light curve with an exponential decay, a knee and a linear decay. We find that the disc has an outer radius of 1012≲ Rout≲1013 cm, only an order of magnitude larger than typical accretion discs in the high/soft state of Galactic black holes. By contrast, the semimajor axis is ≈ a few ×1014 cm. This discrepancy can be explained with a highly eccentric orbit. We estimate the tidal truncation radius and circularization radius around the black hole at periastron, and impose that they are similar or smaller than the outer disc radius. We obtain that e ≳ 0.95, that the radius of the donor star is ≲ a few solar radii and that the donor star is not at risk of tidal disruption. If the companion star fills its Roche lobe and impulsively transfers mass only around periastron, secular evolution of the orbit is expected to increase eccentricity and semimajor axis even further. We speculate that such extremely eccentric systems may have the same origin as the S stars in the Galactic Centre. © 2012 The Author.
Wynaden D.,Curtin University Australia
International Journal of Mental Health Nursing | Year: 2010
One in five Australians has a diagnosable mental illness and the impact of the illness on the individual, their family, and the community is significant. Since comprehensive nursing was introduced in the 1980s there have been repeated concerns raised regarding the preparedness of graduates from Australian undergraduate nursing programs to care for people who have a mental illness. In 2009, despite a recent comprehensive national review of the mental health/illness content in pre-registration curricula, these concerns remain.The nursing profession must have a responsibility to the global community to ensure that registered nurses are educated to meet evolving health challenges and the needs of the health consumer in the 21st Century. The purpose of this paper is to highlight the prevalence and impact of mental illness on health care outcomes in all settings and to challenge the profession to acknowledge that mental health nursing content must be a core area of all undergraduate curricula. A nationally coordinated response to address the long standing identified deficits in the educational preparation of comprehensive nurses is now a priority to ensure that nurses remain a major stakeholder group in the delivery of health care and key health informants and decision makers within the global health care arena. © 2010 The Author. Journal compilation © 2010 Australian College of Mental Health Nurses Inc.
Lentillon-Kaestner V.,University of Lausanne |
Hagger M.S.,Curtin University Australia |
Hardcastle S.,University of Brighton
Scandinavian Journal of Medicine and Science in Sports | Year: 2012
The protection of the health of athletes is one of the three criteria taken into account when registering a substance in the World Anti-Doping Agency prohibited list. Nevertheless, in elite-level cycling, banned substance use is widespread. The present research adopted a psychological approach to examine how or whether perceived health risks influence elite-level cyclists' decisions to use banned substances. Sixteen semi-structured interviews were conducted with cyclists hoping to join a professional team (n=6), neo-professional cyclists (n=2), and former professional cyclists (n=8). Although an evolution was observed in the organization of doping and perceptions of doping over the last decade, the perceived health hazards did not influence, most of the time, decisions to use banned substances among the sample of cyclists. There was a systematization of exogenous substance use in the cycling environment and a trivialization of the side effects of the banned substances. Finally, younger cyclists were not concerned about the long-term health consequences of banned substances; they were more focused on the short-term performance-enhancing benefits. There is a need to implement more effective preventive programs to change athletes' attitudes toward doping and its health risks. © 2011 John Wiley & Sons A/S.
Nohut S.,Zirve University |
Lu C.,Curtin University Australia
Ceramics International | Year: 2012
The Weibull distribution is the most widely used function in the reliability analysis and structural design of dental ceramics; however, it is still unclear whether Weibull distribution is always the most suitable one. With wide applications of dental ceramics, a special attention has been paid in discriminating their strength distributions. In this paper, three versatile functions, involving normal, log-normal and Weibull distributions, are applied to the analysis of ten strength data sets of dental ceramics with different compositions and the results are compared in terms of the Akaike information criterion and the Anderson-Darling test. It reveals that various microstructures and compositions in the investigated dental ceramics cause their strength distributions deviated from the Weibull distribution. The influence of microstructure induced fracture properties (multiple-modal flaw size distribution, R-curve behavior and subcritical crack growth) on strength distributions is discussed. © 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
McKee H.C.,University of Birmingham |
Ntoumanis N.,University of Birmingham |
Ntoumanis N.,Curtin University Australia |
Taylor I.M.,Loughborough University
Annals of Behavioral Medicine | Year: 2014
Purpose The aim of this study is to investigate the factors related to dietary lapse occurrence in a community sample of dieters. Methods An ecological momentary assessment (EMA) methodology, via mobile phone-based diaries, was employed to record dietary lapse occurrences in a group of dieters (N = 80; Mage = 41.21 ± 15.60 years; MBMI = 30.78 ± 7.26) over 7 days. Results Analyses indicated that lapses were positively associated with the strength of dietary temptation, presence of others, coping responses, and the environment (exposure to food cues) in which the dieters were in; lapses were more likely to occur in the evening and were negatively associated with the use of coping mechanisms. Additionally, lapse occurrence was found to mediate the relationships among the above predictors of lapse and the self-efficacy to resist future dietary temptations. Conclusions Results provide an insight into the occurrence of lapses in dieters and have implications for interventions focusing on weight loss maintenance and relapse prevention. © 2014 The Society of Behavioral Medicine.
Glasser L.,Curtin University Australia
Inorganic Chemistry | Year: 2010
Thermodynamic properties such as entropy, among others, have been shown to correlate well with formula volume, thus permitting prediction of these properties on the basis of chemical formula and density alone, with no structural detail required. We here extend these studies to the thermoelastic property of isothermal compressibility, β. We show that compressibility is strongly linearly correlated with formula volume per atom pair, Vpr, for binary solids, with the alkali halides having a proportionality constant of 0.908 GPa-1 Vpr-1 while 1:1 monoxides, monochalcogenides, monopnictides, and chalcopyrites (ABX2, which may be considered as AX plus BX) have a common compressibility proportionality constant of 0.317 GPa-1 Vpr-1. Oxides with closely packed oxygen lattices (such as Al2O3), garnets (such as Y 3Fe5O12 = 4M2O3), spinels (MgAl2O4 = MgO3 Al2O3), and other oxides (e.g., FeTiO3 = FeO · TiO2) have compressibilities which are only slightly dependent on volume, at about 0.108 GPa-1 Vpr-1 + 0.003 GPa-1. © 2010 American Chemical Society.
Bahadori A.,Curtin University Australia
Applied Energy | Year: 2011
In one tube pass and one shell pass counter-flow heat exchangers, when both streams change temperature by different amounts, the effectiveness is defined as the temperature change for the stream with lower capacity divided by the maximum possible change and the effectiveness depends on the number of transfer units and the thermal capacity ratio. In this paper, an attempt has been made to formulate a simple-to-use method which is easier than existing approaches, less complicated and with fewer computations for accurate and rapid estimation of effectiveness in one tube pass and one shell pass counter-flow heat exchangers as a function of number of transfer units and the thermal capacity ratio. The proposed method permits estimating the exit temperature for a one tube pass and one shell pass counter-flow heat exchanger without a trial-and-error calculation. The average absolute deviations between the reported data and the proposed correlations are found to be less than 2% demonstrating the excellent performance of proposed correlation. The tool developed in this study can be of immense practical value for engineers and scientists to have a quick check on the effectiveness in one tube pass and one shell pass counter-flow heat exchangers at various conditions without opting for any experimental measurements. In particular, practice engineers would find the predictive tool to be user-friendly with transparent calculations involving no complex expressions. © 2011 Elsevier Ltd.
Do K.D.,Curtin University Australia
Robotics and Autonomous Systems | Year: 2015
Although environmental loads induced by waves, wind, and ocean currents on marine vessels are naturally stochastic, all existing works on controlling these vehicles treat these loads as deterministic. This treatment deteriorates the control performance in a practical implementation. This paper presents a method to design controllers that force an underactuated omni-directional intelligent navigator (ODIN), a spherical underwater vehicle, to track a reference trajectory in two-dimensional space. Motivated by the vehicle's steering practice, the yaw angle regarded as a virtual control plus the surge thrust force are used to force the position of the vehicle to globally track its reference trajectory. The control design is based on several recent results developed for stability and control of stochastic systems, potential projection functions, and backstepping and Lyapunov's direct methods. Simulations are included to illustrate the effectiveness of the proposed results. © 2015 Elsevier B.V. All rights reserved.
Suenaga H.,Curtin University Australia |
Smith A.,University of California at Davis
Energy Journal | Year: 2011
We examine the volatility dynamics of three major petroleum commodities traded on the NYMEX: crude oil, unleaded gasoline, and heating oil. Using the partially overlapping time-series (POTS) framework of Smith (2005), we model jointly all futures contracts with delivery dates up to a year into the future and extract information from these prices about the persistence of market shocks. The model depicts highly nonlinear volatility dynamics that are consistent with the observed seasonality in demand and storage of the three commodities. Specifically, volatility of the three commodity prices exhibits time-to-delivery effects and substantial seasonality, yet their patterns vary systematically by contract delivery month. The conditional variance and correlation across the three commodities also vary over time. High price volatility of near-delivery contracts and their low correlation with concurrently traded distant contracts imply high shorthorizon price risk for an unhedged position in the calendar or crack spread. Price risk at the one-year horizon is much lower than short-horizon risk in all seasons and for all positions, but it is still substantial in magnitude for crack-spread positions. Crack-spread hedgers ignore nearby high-season price risk at their peril, but they would also be remiss to ignore the long horizon. Copyright © 2011 by the IAEE. All rights reserved.
Joyeux R.,Macquarie University |
Ripple R.D.,Curtin University Australia
Energy Journal | Year: 2011
The direction of the causality between energy consumption and income is an important issue in the fields of energy economics, economic growth, and policies toward energy use. The seminal work on the relations between energy consumption and aggregate income is Kraft and Kraft (1978). An extensive literature has followed, but the array of findings provide anything but consensus on either the existence of relations or direction of causality between the variables. The work in this paper extends this research by analysing the cointegrating and causal relations between income and three energy consumption series based on panel data and the latest panel methodologies. These relations are analysed for the 30 OECD countries and 26 non-OECD countries. The results support a finding of causality flowing from income to energy consumption for developed and developing economies, alike. Copyright © 2011 by the IAEE. All rights reserved.
Sun Z.,Curtin University Australia |
Ng K.-H.,University of Malaya
European Journal of Radiology | Year: 2012
Purpose: To perform a systematic review of the radiation dose and diagnostic accuracy of prospective versus retrospective ECG-gated multislice CT coronary angiography. Materials and methods: A search of Pubmed/Medline and Sciencedirect databases for English literature was performed to identify studies comparing prospective and retrospective ECG-gated multislice CT angiography in the diagnosis of coronary artery disease. Effective dose, dose length product, image quality and diagnostic value were compared between two groups of studies. Results: 22 studies were included for analysis. The mean effective dose of prospective ECG-gated scans was 4.5 mSv (95% CI: 3.6, 5.3 mSv), which is significantly lower than that of retrospective scans, which is 13.8 mSv (95% CI: 11.5, 16.0 mSv) (p < 0.001). The mean dose length product was 225 mGy cm (95% CI: 188, 262 mGy cm) and 822 mGy cm (95% CI: 630, 1013 mGy cm) for the prospective and retrospective ECG-gated scans, respectively, indicating a statistically significant difference between these two protocols (p < 0.0001). The mean sensitivity and specificity of multislice CT angiography in the diagnosis of coronary artery disease was 97.7% (95% CI: 93.7%, 100%) and 92.1% (95% CI: 87.2%, 97%) for prospective ECG-gated scans; 95.2% (95% CI: 91%, 99.5%) and 94.4% (95% CI: 88.5%, 100%) for retrospective ECG-gated scans, respectively, with no significant difference for sensitivity but significant difference for specificity (p = 0.047). Conclusion: Multislice CT coronary angiography with prospective ECG-gating leads to a significant reduction of radiation dose when compared to that of retrospective ECG-gating, while offering comparable image quality and diagnostic value. © 2011 Elsevier Ireland Ltd. All rights reserved.
Chaudhary D.S.,Curtin University Australia
Journal of Applied Polymer Science | Year: 2010
Two plasticizers namely, glycerol and xylitol, based on their similar molecular diameter (∼ 6.3 Å) but different molecular weights (glycerol-92; xylitol-152) were selected were selected for studying the plasticization of starch biopolymer containing 70% amylopectin structure via glass transition measurements carried over a wide range of water activity. A standard calorimetry was used to determine the onset temperature of polymeric viscous flow. For both glycerol and xylitol, typical antiplasticization was evident at low plasticizer concentrations, whereas at higher concentration, there was significant reduction in glass transition temperature. Water activity isotherms showed that equilibrium moisture content of the starchbiopolymer (no plasticizer) steadily increases up to 11%, however, for plasticized biopolymer, the moisture content was nearly double than that of biopolymer. We used a modified Gordon-Taylor model, using a new interaction parameter, to understand the competitive plasticization of glycerol and xylitol in presence of water, and determined 8 wt % water as a threshold amount of matrix water for strong three-way interactions: starch-plasticizer, plasticizerplasticizer/water and starch-water. © 2010 Wiley Periodicals, Inc.
Ntogramatzidis L.,Curtin University Australia |
Ferrante A.,University of Padua
Systems and Control Letters | Year: 2010
In this paper we consider the matrix Riccati differential equation (RDE) that arises from linear-quadratic (LQ) optimal control problems. In particular, we establish explicit closed formulae for the solution of the RDE with a terminal condition using particular solutions of the associated algebraic Riccati equation. We discuss how these formulae change as assumptions are progressively weakened. An application to LQ optimal control is briefly analysed. © 2010 Elsevier B.V. All rights reserved.
Glasser L.,Curtin University Australia |
Jenkins H.D.B.,University of Warwick
Inorganic Chemistry | Year: 2011
Thermodynamic properties, such as standard entropy, among others, have been shown to correlate well with formula volume, V m, thus permitting prediction of these properties on the basis of chemical formula and density alone, with no structural detail required. We have termed these procedures "volume-based thermodynamics" (VBT). We here extend these studies to ambient isobaric heat capacities, C p,m, of a wide range of materials. We show that heat capacity is strongly linearly correlated with formula volume for large sets of minerals, for ionic solids in general, and for ionic liquids and that the results demonstrate that the Neumann-Kopp rule (additivity of heat capacity contributions per atom) is widely valid for ionic materials, but the smaller heat capacity contribution per unit volume for ionic liquids is noted and discussed. Using these correlations, it is possible to predict values of ambient (298 K) heat capacities quite simply. We also show that the heat capacity contribution of water molecules of crystallization is remarkably constant, at 41.3 ± 4.7 J K -1 (mol of water) -1, so that the heat capacities of various hydrates may be reliably estimated from the values of their chemical formula neighbors. This result complements similar observations that we have reported for other thermodynamic differences of hydrates. © 2011 American Chemical Society.
Sunarso J.,University of Queensland |
Liu S.,Curtin University Australia |
Lin Y.S.,Arizona State University |
Diniz Da Costa J.C.,University of Queensland
Energy and Environmental Science | Year: 2011
Here we report the production of novel high performance BaBi 0.05Sc0.1Co0.85O3-δ (BaBiScCo) hollow fibres delivering oxygen fluxes of 11.4 ml cm-2 min -1 at 950 °C. The doping of bismuth, a highly ionic conductor, at the B-site of a barium based perovskite overcame oxygen ionic transport limitations even at temperatures as low as 600 °C. © 2011 The Royal Society of Chemistry.
Do K.D.,Curtin University Australia
Systems and Control Letters | Year: 2015
Optimality has not been addressed in existing works on control of (stochastic) nonholonomic systems. This paper presents a design of optimal controllers with respect to a meaningful cost function to globally asymptotically stabilize (in probability) nonholonomic systems affine in stochastic disturbances. The design is based on the Lyapunov direct method, the backstepping technique, and the inverse optimal control design. A class of Lyapunov functions, which are not required to be as nonlinearly strong as quadratic or quartic, is proposed for the control design. Thus, these Lyapunov functions can be applied to design of controllers for underactuated (stochastic) mechanical systems, which are usually required Lyapunov functions of a nonlinearly weak form. The proposed control design is illustrated on a kinematic cart, of which wheel velocities are perturbed by stochastic noise. © 2014 Elsevier B.V. All rights reserved.
Dam H.H.,Curtin University Australia |
Cantoni A.,University of Western Australia
Signal Processing | Year: 2015
This paper proposes a new computational procedure for solving the optimal zero-forcing beamforming problem in multiple antenna channels that maximizes user achievable rate with restriction on the per-antenna element power constraints. An interior point method with optimal step size procedure is developed in which the step size for the line search in the Newton search direction is calculated exactly for each iteration. This significantly enhances the efficiency associated with the line search. Design examples show that the proposed algorithm converges rapidly to the optimal solution with low computational complexity. © 2014 Published by Elsevier B.V. All rights reserved.
Dokuchaev N.,Curtin University Australia
IEEE Signal Processing Letters | Year: 2015
We study the problem of the transmission of currently observed time variable signals via a channel that is capable of sending a single binary signal only for each measurement of the underlying process. For encoding and decoding, we suggest a modification of the adaptive delta modulation algorithm. This modification ensures tracking of time variable signals. We obtained upper estimates for the error for the case of noiseless transmission. © 2015 IEEE.
Bostock C.J.,Curtin University Australia
Journal of Physics B: Atomic, Molecular and Optical Physics | Year: 2011
The calculation of accurate excitation and ionization cross sections for electron collisions with atoms and ions plays a fundamental role in atomic and molecular physics, laser physics, x-ray spectroscopy, plasma physics and chemistry. Within the veil of plasma physics lie important research areas affiliated with the lighting industry, nuclear fusion and astrophysics. For high energy projectiles or targets with a large atomic number it is presently understood that a scattering formalism based on the Dirac equation is required to incorporate relativistic effects. This tutorial outlines the development of the relativistic convergent close-coupling (RCCC) method and highlights the following three main accomplishments. (i) The inclusion of the Breit interaction, a relativistic correction to the Coulomb potential, in the RCCC method. This led to calculations that resolved a discrepancy between theory and experiment for the polarization of x-rays emitted by highly charged hydrogen-like ions excited by electron impact (Bostock et al 2009 Phys. Rev. A 80 052708). (ii) The extension of the RCCC method to accommodate two-electron and quasi-two-electron targets. The method was applied to electron scattering from mercury. Accurate plasma physics modelling of mercury-based fluorescent lamps requires detailed information on a large number of electron impact excitation cross sections involving transitions between various states (Bostock et al 2010 Phys. Rev. A 82 022713). (iii) The third accomplishment outlined in this tutorial is the restructuring of the RCCC computer code to utilize a hybrid OpenMP-MPI parallelization scheme which now enables the RCCC code to run on the latest high performance supercomputer architectures. © 2011 IOP Publishing Ltd.
Biswas W.K.,Curtin University Australia
Energy for Sustainable Development | Year: 2011
Renewable energy can potentially play a role in the supply of safe water in Bangladesh, where nearly 70% of the rural population does not have access to electricity. This paper examines the possible application of renewable energy for pumping water from geologically safe deep tubewells to overcome limitations in existing water technologies in the arsenic-contaminated villages in Bangladesh. Renewable energy, national grid electricity, and alternatives such as diesel engines have been considered as sources of power for both suction and submersible pumps in electrified and non-electrified villages. Three locally available renewable energy sources (human energy, biogas, and solar energy) have been assessed as power sources for reciprocating and submersible pumps. These renewable energy options have not been found cost competitive with the deep tubewells which run off the national grid in electrified villages. However, electricity generated from biogas has the potential to power submersible pumps in non-electrified villages. This paper discusses some financial mechanisms to promote capital-intensive energy options for deep tubewells in arsenic-affected rural areas. © 2010 International Energy Initiative.
Hagger M.S.,Curtin University Australia
Behavioral and Brain Sciences | Year: 2013
I contend that Kurzban et al.'s model is silent on three issues. First, the extent to which opportunity-cost computations are automatic or deliberative is unclear. Second, the role of individual differences in biasing opportunity-cost computations needs elucidating. Third, in the absence of "next-best" tasks, task persistence will be indefinite, which seems unfeasible, so perhaps integration with a limited-resource account is necessary. © Cambridge University Press 2013.
Elhamirad A.H.,Islamic Azad University at Sabzevar |
Zamanipoor M.H.,Curtin University Australia
European Journal of Lipid Science and Technology | Year: 2012
In this study, the thermal stability of some phenolic antioxidants including flavonoids (quercetin and catechin) and phenolic acids (gallic acid, tannic acid, ellagic acid and caffeic acid) in tallow olein was investigated. Tallow olein fractionated from sheep tallow fat was used as a medium to study the antioxidant activity at 120, 140, 160 and 180°C. In order to extract tallow olein, a three-stage fractionation method was performed on sheep tallow fat at the constant temperatures of 25, 15 and 5°C using acetone as a solvent. The results suggested that quercetin and ellagic acid had the highest thermal stability amongst others, while gallic acid and caffeic acid exhibited the least thermal stability. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Stokes S.F.,Curtin University Australia
Journal of Speech, Language, and Hearing Research | Year: 2010
Purpose: To document the lexical characteristics of neighborhood density (ND) and word frequency (WF) in the lexicons of a large sample of English-speaking toddlers. Method: Parents of 222 British-English-speaking children aged 27(±3) months completed a British adaptation of the MacArthur-Bates Communicative Development Inventory: Words and Sentences (MCDI; Klee & Harrison, 2001). Child words were coded for ND and WF, and the relationships among vocabulary, ND, and WF were examined. A cut-point of -1 SD below the mean on the MCDI classified children into one of two groups: low or high vocabulary size. Group differences on ND and WF were examined using nonparametric statistics. Results: In a hierarchical regression, ND and WF accounted for 47% and 14% of unique variance in MCDI scores, respectively. Low-vocabulary children scored significantly higher on ND and significantly lower on WF than did high-vocabulary children, but there was more variability in ND and WF for children at the lowest points of the vocabulary continuum. Conclusion: Children at the lowest points of a continuum of vocabulary size may be extracting statistical properties of the input language in a manner quite different from their more able age peers. © American Speech-Language- Hearing Association.
Wang S.,Nanyang Technological University |
Wang X.,Nanyang Technological University |
Jiang S.P.,Curtin University Australia
Physical Chemistry Chemical Physics | Year: 2011
Pt and Au nanoparticles with controlled Pt:Au molar ratios and PtAu nanoparticle loadings were successfully self-assembled onto poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene (PDDA-G) as highly effective electrocatalysts for formic acid oxidation in direct formic acid fuel cells (DFAFCs). The simultaneously assembled Pt and Au nanoparticles on PDDA-G showed superb electrocatalytic activity for HCOOH oxidation, and the current density associated with the preferred dehydrogenation pathway for the direct formation of CO2 through HCOOH oxidation on a Pt 1Au8/PDDA-G (i.e., a Pt:Au ratio of 1:8) is 32 times higher than on monometallic Pt/PDDA-G. The main function of the Au in the mixed Pt and Au nanoparticles on PDDA-G is to facilitate the first electron transfer from HCOOH to HCOOads and the effective spillover of HCOO ads from Au to Pt nanoparticles, where HCOOads is further oxidized to CO2. The Pt:Au molar ratio and PtAu nanoparticle loading on PDDA-G supports are the two critical factors to achieve excellent electrocatalytic activity of PtAu/PDDA-G catalysts for the HCOOH oxidation reactions. © the Owner Societies 2011.
Wang S.,Nanyang Technological University |
Wang X.,Nanyang Technological University |
Jiang S.P.,Curtin University Australia
Physical Chemistry Chemical Physics | Year: 2011
Pt and Au nanoparticles with controlled Pt :Au molar ratios and PtAu nanoparticle loadings were successfully self-assembled onto poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene (PDDA-G) as highly effective electrocatalysts for formic acid oxidation in direct formic acid fuel cells (DFAFCs). The simultaneously assembled Pt and Au nanoparticles on PDDA-G showed superb electrocatalytic activity for HCOOH oxidation, and the current density associated with the preferred dehydrogenation pathway for the direct formation of CO2 through HCOOH oxidation on a Pt1Au8/PDDA-G (i.e., a Pt :Au ratio of 1 : 8) is 32 times higher than on monometallic Pt/PDDA-G. The main function of the Au in the mixed Pt and Au nanoparticles on PDDA-G is to facilitate the first electron transfer from HCOOH to HCOOads and the effective spillover of HCOOads from Au to Pt nanoparticles, where HCOOads is further oxidized to CO2. The Pt :Au molar ratio and PtAu nanoparticle loading on PDDA-G supports are the two critical factors to achieve excellent electrocatalytic activity of PtAu/PDDA-G catalysts for the HCOOH oxidation reactions. © the Owner Societies 2011.
Rasouli V.,Curtin University Australia |
Harrison J.P.,Imperial College London
International Journal of Rock Mechanics and Mining Sciences | Year: 2010
The mechanical behaviour of rock masses is complex, due partly to the presence of discontinuities within them. Of the geometrical parameters of discontinuities, surface roughness, which encapsulates the topographical features of a rock surface, is known to play a significant role. Here, a new parameter for quantitative roughness determination based on the distribution of unit normal vectors to a rock profile is presented. The analysis of unit normal vectors in terms of directional statistics is customarily performed in Euclidean space using a Cartesian co-ordinate system. Here, the analysis is developed using Riemannian geometry, with Mahalanobis distances being proposed for discrimination between different rock profiles. Statistical parameters on the unit circle are extracted using Riemannian geometry, and from that a roughness parameter, D R1, is obtained. This parameter corresponds to 1D Riemannian dispersion, and as such D R1 increases as profile roughness increases. D R1 is applied to the analysis of synthetic profiles and some real rock profiles. Conclusions are drawn that demonstrate the advantages of the new method in terms of investigating the scale effect in roughness determination as well as in comparing different profiles. A preliminary study into the correlation between D R1 and the shear strength of a fracture, using analytical and numerical investigation of the strength of profiles comprising symmetric triangular asperities sheared at different normal stress levels, shows a clear relation between Riemannian roughness parameter and profile shear strength. © 2010.
Wilde S.A.,Curtin University Australia
Precambrian Research | Year: 2010
Rare felsic volcanic rocks of dacitic to rhyolitic composition occur in the central part of the Jack Hills metasedimentary belt in the Narryer Terrane of Western Australia, interleaved with clastic sedimentary rocks and amphibolite. Representative samples of the four identified felsic volcanic units reveal a similar complex pattern of zircon age distribution, with all samples containing zircon populations at ~3.3-3.4, ~3.0-3.1, ~2.6 and ~1.8-1.9. Ga. The ~3.3-3.4. Ga zircons show well-developed oscillatory zoning in cathodoluminescence (CL) images and are interpreted as inherited igneous zircon derived from granitic precursors, similar to the ~3.3. Ga trondhjemitic granitoids currently exposed along the northern and southern margins of the belt. The ~3.0-3.1. Ga zircons also reveal well-developed oscillatory zoning in CL and are most likely derived from granitoid and/or volcanic rocks of this age, as recorded in the Murchison domain to the south and possibly also present in the Narryer Terrane. The ~2.6. Ga population matches the age of nearby late Archean granitoids intruding the Jack Hills belt and their oscillatory zoning and U-Th chemistry is consistent with their origin from such a source. The youngest discrete group of zircon grains, with ages ranging from ~1970 to ~1775. Ma, show strong oscillatory zoning and average Th/U ratios of 0.76, features consistent with an igneous origin. These younger zircons are therefore interpreted as defining the age of crystallisation of the volcanic rocks. These results establish that the Jack Hills metasedimentary belt contains significant post-Archean components. Taken together with similar results obtained from zircon occurring as detrital grains in clastic sedimentary rocks at Jack Hills, these results overturn the generally-accepted view that the belt is entirely Archean in age and that sedimentation was completed around 3.0. Ga ago. Instead, there is a distinct possibility that much of the material currently exposed in the Jack Hills belt formed in the Proterozoic. A further implication of this study is that the metamorphism affecting these rocks also occurred in the Proterozoic and consequently the rocks should not be considered as forming an Archean greenstone or metasedimentary belt. The paucity of zircons >4. Ga in the known Proterozoic sedimentary rocks and their total absence in the felsic volcanic rocks suggests that such ancient source rocks were no longer present in the area. © 2010 Elsevier B.V.
Teunissen P.J.G.,Curtin University Australia |
Teunissen P.J.G.,Technical University of Delft
Journal of Geodesy | Year: 2010
Global navigation satellite system (GNSS) carrier phase integer ambiguity resolution is the key to high-precision positioning and attitude determination. In this contribution, we develop new integer least-squares (ILS) theory for the GNSS compass model, together with efficient integer search strategies. It extends current unconstrained ILS theory to the nonlinearly constrained case, an extension that is particularly suited for precise attitude determination. As opposed to current practice, our method does proper justice to the a priori given information. The nonlinear baseline constraint is fully integrated into the ambiguity objective function, thereby receiving a proper weighting in its minimization and providing guidance for the integer search. Different search strategies are developed to compute exact and approximate solutions of the nonlinear constrained ILS problem. Their applicability depends on the strength of the GNSS model and on the length of the baseline. Two of the presented search strategies, a global and a local one, are based on the use of an ellipsoidal search space. This has the advantage that standard methods can be applied. The global ellipsoidal search strategy is applicable to GNSS models of sufficient strength, while the local ellipsoidal search strategy is applicable to models for which the baseline lengths are not too small. We also develop search strategies for the most challenging case, namely when the curvature of the non-ellipsoidal ambiguity search space needs to be taken into account. Two such strategies are presented, an approximate one and a rigorous, somewhat more complex, one. The approximate one is applicable when the fixed baseline variance matrix is close to diagonal. Both methods make use of a search and shrink strategy. The rigorous solution is efficiently obtained by means of a search and shrink strategy that uses non-quadratic, but easy-to-evaluate, bounding functions of the ambiguity objective function. The theory presented is generally valid and it is not restricted to any particular GNSS or combination of GNSSs. Its general applicability also applies to the measurement scenarios (e. g. single-epoch vs. multi-epoch, or single-frequency vs. multi-frequency). In particular it is applicable to the most challenging case of unaided, single frequency, single epoch GNSS attitude determination. The success rate performance of the different methods is also illustrated. © 2010 The Author(s).
Aguilera R.F.,Curtin University Australia
Energy Exploration and Exploitation | Year: 2011
This paper estimates petroleum endowment volumes for provinces of the Former Soviet Union (FSU) that have not been previously assessed by other organizations. The study uses the United States Geological Survey World Petroleum Assessment (USGS, 2000) as a starting point. It then utilizes nonlinear regression to estimate parameters of a Variable Shape Distribution (VSD) model that calculates the total petroleum endowment throughout the FSU. Earlier size distribution models used to evaluate unassessed petroleum resources relied mainly on the fractal and lognormal distributions. In fact, all the methods used historically have been based on an assumed form of the size distribution of nature's endowment of petroleum resources. The VSD model is different in that it allows the actual petroleum resource data from USGS (2000) to determine the form of the size distribution of petroleum resources. The model is validated by a good fit of actual data, supported by coefficients of determination (R 2) equal to 0.98 or greater. It is concluded that there is a large petroleum endowment in the FSU that will last for several decades and can contribute significantly to domestic energy needs as well as export requirements.
Bahadori A.,Curtin University Australia
Applied Thermal Engineering | Year: 2011
When cooling combustion flue gas for heat recovery and efficiency gain, the temperature must not be allowed to drop below the sulfur trioxide dew point. Below the SO3 dew point, very corrosive sulfuric acid forms and leads to operational hazards on metal surfaces. In the present work, simple-to-use predictive tool, which is easier than existing approaches, less complicated with fewer computations is formulated to arrive at an appropriate estimation of acid dew point during combustion flue gas cooling which depends on fuel type, sulfur content in fuel, and excess air levels. The resulting information can then be applied to estimate the acid dew point, for sulfur in various fuels up to 0.10 volume fraction in gas (0.10 mass fraction in liquid), excess air fractions up to 0.25, and elemental concentrations of carbon up to 3. The proposed predictive tool shows a very good agreement with the reported data wherein the average absolute deviation percent was found to be around 3.18%. This approach can be of immense practical value for engineers and scientists for a quick estimation of acid dew point during combustion flue gas cooling for heat recovery and efficiency gain for wide range of operating conditions without the necessity of any pilot plant setup and tedious experimental trials. In particular, process and combustion engineers would find the tool to be user friendly involving transparent calculations with no complex expressions for their applications. © 2011 Elsevier Ltd. All rights reserved.
Ma Z.S.,Xiangtan University |
Zhou Y.C.,Xiangtan University |
Long S.G.,Xiangtan University |
Lu C.,Curtin University Australia
International Journal of Plasticity | Year: 2012
To examine effects of indentation size and substrate on the hardness determination of thin films, two typical types of hard film/soft substrate (Ni/Fe) and soft film/hard substrate (Al/Si and Al/glass) systems are investigated. A simple model is proposed to predict the intrinsic hardness of thin films, which allows a more accurate fitting to empirical data and the estimation of ultimate film hardness. The model can be used to interpret indentation data and extrapolate the indentation depth-hardness curve to an important region where indentation depth lies between 1% to 5 times of film thickness. The results are well consistent with the evolving trend of composite hardness obtained from experiments and numerical results by finite element analysis. © 2012 Published by Elsevier Ltd. All rights reserved.
Brewer M.L.,Curtin University Australia |
Stewart-Wynne E.G.,Clinical Services
Journal of Interprofessional Care | Year: 2013
Royal Perth Hospital, in partnership with Curtin University, established the first interprofessional student training ward in Australia, based on best practice from Europe. Evaluation of the student and client experience was undertaken. Feedback from all stakeholders was obtained regularly as a key element of the quality improvement process. An interprofessional practice program was established with six beds within a general medical ward. This provided the setting for 2- to 3-week clinical placements for students from medicine, nursing, physiotherapy, occupational therapy, social work, pharmacy, dietetics and medical imaging. Following an initial trial, the training ward began with 79 students completing a placement. An interprofessional capability framework focused on the delivery of high quality client care and effective teamwork underpins this learning experience. Quantitative outcome data showed not only an improvement in students' attitudes towards interprofessional collaboration but also acquisition of a high level of interprofessional practice capabilities. Qualitative outcome data from students and clients was overwhelmingly positive. Suggestions for improvement were identified. This innovative learning environment facilitated the development of the students' knowledge, skills and attitudes required for interprofessional, client centred collaborative practice. Staff reported a high level of compliance with clinical safety and quality. © 2013 Informa UK Ltd.
Metelkin D.V.,Russian Academy of Sciences |
Vernikovsky V.A.,Russian Academy of Sciences |
Kazansky A.Y.,Russian Academy of Sciences |
Wingate M.T.D.,Curtin University Australia
Gondwana Research | Year: 2010
This paper presents paleomagnetic data for Late Mesozoic (Middle Jurassic to end-Cretaceous) rocks of the Siberian platform (Verkhoyansk Trough) and its southwestern margin (Transbaikalian basins and Minusa Trough). We determine a series of key paleomagnetic poles for 165, 155, 135, 120, and 75. Ma, which define the Mesozoic apparent polar wander path (APWP) for Siberia. This quantitative approach provides the opportunity for a general revision of Mesozoic tectonics of Central Asia. Many researchers have considered the Eurasian continent to have been completely stable during the Mesozoic era. However, we demonstrate systematic deviations of corresponding Mesozoic poles from Siberia and Europe, and interpret the discrepancies as evidence for large-scale sinistral strike-slip motion due to clockwise rotation of the Siberian plate relative to the European plate. We conclude that, following its Late Paleozoic assembly, the Eurasian plate was not internally stable, i.e. not rigid. The Mesozoic geological evolution of Siberia was dominated by strike-slip tectonics. Rift-related grabens formed within the basement of the West Siberia sedimentary basin and orogenic events occurred along the southwestern margin of the Siberian craton, within the Central Asia tectonic province. Our paleomagnetic reconstruction indicates also that the Mongol-Okhotsk Ocean was still not closed completely before the end of the Jurassic. We propose that final collision occurred in the Early Cretaceous, and during the Middle to Late Jurassic interval, northward subduction of oceanic lithosphere resulted in oblique, west-to-east ocean closure (a "scissors-like" model). The closure was controlled by significant sinistral strike-slip motion of the Siberian craton. This process is reflected in Transbaikalia by extensive bimodal volcanic activity and development of rift-related structures, including pull-apart basins. © 2010 International Association for Gondwana Research.
Rong Y.,Curtin University Australia
IEEE Transactions on Signal Processing | Year: 2012
In this paper, we investigate the challenging problem of joint source and relay optimization for two-way linear non-regenerative multiple-input multiple-output (MIMO) relay communication systems. We derive the optimal structure of the source and relay precoding matrices when linear minimal mean-squared error (MMSE) receivers are used at both destinations in the relay system. We show that for a broad class of frequently used objective functions for MIMO communications such as the MMSE, the maximal mutual information (MMI), and the minimax MSE, the optimal relay and source matrices have a general beamforming structure. This result includes existing works as special cases. Based on this optimal structure, a new iterative algorithm is developed to jointly optimize the relay and source matrices. We also propose a novel suboptimal relay precoding matrix design which significantly reduces the computational complexity of the optimal design with only a marginal performance degradation. Interestingly, we show that this suboptimal relay matrix is indeed optimal for some special cases. The performance of the proposed algorithms are demonstrated by numerical simulations. It is shown that the novel minimax MSE-based two-way relay system has a better bit-error-rate (BER) performance compared with existing two-way relay systems using the MMSE and the MMI criteria. © 1991-2012 IEEE.
Middleton M.J.,Astronomical Institute Anton Pannekoek |
Miller-Jones J.C.A.,Curtin University Australia |
Fender R.P.,University of Southampton |
Fender R.P.,University of Oxford
Monthly Notices of the Royal Astronomical Society | Year: 2014
Transitions to high mass accretion rates in black hole X-ray binaries are associated with the ejection of powerful, relativistically moving jets. The mechanism that powers such events is thought to be linked to tapping of the angular momentum (spin) of the black hole, the rate of accretion through the disc or some combination of the two. We can attempt to discriminate between these different possibilities by comparing proxies for jet power with spin estimates. Because of the small number of sources that reach Eddington mass accretion rates and have therefore been suggested to act as 'standard candles', there has been much recent debate as to whether a significant correlation exists between jet power and black hole spin. We perform continuum fitting to the high-quality, disc-dominated XMM-Newton spectra of the extragalactic microquasar discovered in M31. Assuming prograde spin,we find that for sensible constraints the spin is always very low (a* ≤ 0.15 at 3σ). When combined with a proxy for jet power derived from the maximum 5 GHz radio luminosity during a bright flaring event, we find that the source sits well above the previously reported, rising correlation that would indicate that spin tapping is the dominant mechanism for powering the jets, i.e. it is too 'radio loud' for such a low spin. The notable exceptions require the inclination to be improbably small or the jet to be very fast. We investigate whether this could be a byproduct of selecting prograde-only spin, finding that the data statistically favour a substantially retrograde spin for the same constraints (a* ≤ -0.17 at 3σ). Although theoretically improbable, this remarkable finding could be confirmation that retrograde spin can power such jets via spin-tapping, as has been suggested for certain radio quasars. In either case this work demonstrates the value of studying local extragalactic microquasars as a means to better understand the physics of jet launching. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
Evans K.A.,Curtin University Australia |
Powell R.,University of Melbourne |
Holland T.J.B.,University of Cambridge
Journal of Metamorphic Geology | Year: 2010
The Holland and Powell internally consistent data set version 5.5 has been augmented to include pyrite, troilite, trov (Fe0.875S), anhydrite, H2S, elemental S and S2 gas. Phase changes in troilite and pyrrhotite are modelled with a combination of multiple end-members and a Landau tricritical model. Pyrrhotite is modelled as a solid solution between hypothetical end-member troilite (trot) and Fe0.875S (trov); observed activity-composition relationships fit well to a symmetric formalism model with a value for wtrot-trov of -3.19 kJ mol-1. The hypothetical end-member approach is required to compensate for iron distribution irregularities in compositions close to troilite. Mixing in fluids is described with the van Laar asymmetric formalism model with aij values for H2O-H2S, H2S-CH4 and H2S-CO2 of 6.5, 4.15 and 0.045 kJ mol-1 respectively. The derived data set is statistically acceptable and replicates the input data and data from experiments that were not included in the initial regression. The new data set is applied to the construction of pseudosections for the bulk composition of mafic greenschist facies rocks from the Golden Mile, Kalgoorlie, Western Australia. The sequence of mineral assemblages is replicated successfully, with observed assemblages predicted to be stable at X(CO2) increasing with increasing degree of hydrothermal alteration. Results are compatible with those of previous work. Assemblages are insensitive to the S bulk content at S contents of less than 1 wt%, which means that volatilization of S-bearing fluids and sulphidation are unlikely to have had major effects on the stable mineral assemblage in less metasomatized rocks. The sequence of sulphide and oxide phases is predicted successfully and there is potential to use these phases qualitatively for geobarometry. Increases in X(CO2) stabilized, in turn, pyrite-magnetite, pyrite-hematite and anhydrite-pyrite. Magnetite-pyrrhotite is predicted at temperatures greater than 410 °C. The prediction of a variety of sulphide and oxide phases in a rock of fixed bulk composition as a function of changes in fluid composition and temperature is of particular interest because it has been proposed that such a variation in phase assemblage is produced by the infiltration of multiple fluids with contrasting redox state. The work presented here shows that this need not be the case. © 2010 Blackwell Publishing Ltd.
Ahmed S.F.U.,Curtin University Australia |
Mihashi H.,Tohoku Institute of Technology
Materials and Structures/Materiaux et Constructions | Year: 2011
Experimental results on the strain hardening and multiple cracking behaviors of polyvinyl alcohol (PVA) fiber reinforced cementitious composites under bending are reported in this paper. Different hybrid combinations of PVA fibers with different lengths and volume fractions are considered to reinforce the mortar matrix. Among different hybrid combinations, the composite containing 2% thicker PVA fibers of 12 mm length and 1% thinner PVA fibers of 6 mm length and the composite containing 2% thicker PVA fibers of 24 mm length and 1% thinner PVA fibers of 6 mm length showed the best performance in terms of highest ultimate load, largest CMOD (crack mouth opening displacement) at peak load and multiple cracking behavior. The effects of four types of light weight sands on the strain hardening and multiple cracking behavior of hybrid fiber composites are also evaluated in this study. It has been observed that the ultimate load and CMOD at peak load for all light weight hybrid fiber composites are almost the same irrespective of volume fractions of light weight sand. The composites containing finer light weight sands exhibited higher ultimate load than those containing coarser light weight sands. It is also observed that the hybrid fiber composite containing normal silica sand exhibited higher ultimate load than the composites with light weight sands. © RILEM 2010.
Mayes R.,Curtin University Australia
Australian Geographer | Year: 2010
This paper focuses on a case study of local postcard production in a rural community in Western Australia. Drawing on in-depth interviews with key producers of these postcards, the analysis presented explores perceptions of and contexts for the emergence of this production, in turn examining the notion of 'creativity' articulated and privileged by this cultural work. Connections are identified between the making of postcards, the broader historical field of local cultural work and the construction of community. This, in turn, forms the basis for consideration of the role and relativity of 'marginality'. © 2010 Geographical Society of New South Wales Inc.
Shahin M.A.,Curtin University Australia
Canadian Geotechnical Journal | Year: 2010
In the last few decades, numerous methods have been developed for predicting the axial capacity of pile foundations. Among the available methods, the cone penetration test (CPT)-based models have been shown to give better predictions in many situations. This can be attributed to the fact that CPT-based methods have been developed in accordance with the CPT results, which have been found to yield more reliable soil properties; hence, more accurate axial pile capacity predictions. In this paper, one of the most commonly used artificial intelligence techniques, i.e., artificial neural networks (ANNs), is utilized in an attempt to develop artificial neural network (ANN) models that provide more accurate axial capacity predictions for driven piles and drilled shafts. The ANN models are developed using data collected from the literature and comprise 80 driven pile and 94 drilled-shaft load tests, as well as CPT results. The predictions from the ANN models are compared with those obtained from the most commonly used available CPT-based methods, and statistical analyses are carried out to rank and evaluate the performance of the ANN models and CPT methods. To facilitate the use of the developed ANN models, they are translated into simple design equations suitable for hand calculations.
Evans K.A.,Curtin University Australia
Mineralium Deposita | Year: 2010
Transitions from pyrrhotite-magnetite- to pyrite-magnetite- and pyrite-hematite-bearing assemblages in metasedimentary rocks in the Kambalda-St. Ives goldfield have been shown to be spatially associated with economic gold grades. Fluid mixing, fluid-rock interaction and phase separation have been proposed previously as causes for this association. Textural, mineralogical and isotopic evidence is reviewed, and thermodynamic calculations are used to investigate the mineralogical consequences of progressive fluid-rock interaction in interflow metasediments. Fluid-rock interactions in response to fluid infiltration and/or bulk composition variation are plausible mechanisms for production of the observed features. © 2009 Springer-Verlag.
Zhang F.,Curtin University Australia |
Oganov A.R.,State University of New York at Stony Brook |
Oganov A.R.,Moscow State University
Geophysical Research Letters | Year: 2010
The Earth's core is expected to contain around 10 wt % light elements (S, Si, O, possibly C, H, etc.) alloyed with Fe and Ni. Very little is known about these alloys at pressures and temperatures of the core. Here, using the evolutionary crystal structure prediction methodology, we investigate Fe-Si compounds at pressures of up to 400 GPa, i.e. covering the pressure range of the Earth's core. Evolutionary simulations correctly find that at atmospheric pressure the known non-trivial structure with P213 symmetry is stable, while at pressures above 20 GPa the CsCl-type structure is stable. We show that among the possible Fe silicides (Fe3Si, Fe2Si, Fe5Si3, FeSi, FeSi2 and FeSi3) only FeSi with CsCltype structure is thermodynamically stable at core pressures, while the other silicides are unstable to decomposition into Fe + FeSi or FeSi + Si. This is consistent with previous works and suggests that Si impurities contribute to stabilization of the body-centered cubic phase of Fe in the inner core. © Copyright 2010 by the American Geophysical Union.
Luker T.,Curtin University Australia
International Journal of Refugee Law | Year: 2013
The increasing global magnitude and exigency of refugee status determination is resulting in recent attention to the parameters of credibility as part of evidentiary assessment in refugee law. In Australia, as in other countries, it is well recognised that applications for review of primary level decisions on refugee status commonly fail on the basis of credibility evidence. Furthermore, it has been suggested that the assessment of credibility is likely to be a source of error in decision making. This article reports on the results of a small-scale study into decision making and credibility assessment at the Australian Refugee Review Tribunal involving interviews with decision makers. Drawing on feminist theories of epistemic responsibility, it argues for a revised standard of proof, suggesting a rebuttable presumption of credibility, or truthfulness, on the part of the applicant seeking asylum. Such an approach may go some way towards addressing the potential for epistemic injustice and is consistent with a position of epistemological responsibility demanded by an ethical obligation to the refugee. © The Author (2013).
Hirt C.,Curtin University Australia
Journal of Geodesy | Year: 2010
This study demonstrates that in mountainous areas the use of residual terrain model (RTM) data significantly improves the accuracy of vertical deflections obtained from high-degree spherical harmonic synthesis. The new Earth gravitational model EGM2008 is used to compute vertical deflections up to a spherical harmonic degree of 2,160. RTM data can be constructed as difference between high-resolution Shuttle Radar Topography Mission (SRTM) elevation data and the terrain model DTM2006.0 (a spherical harmonic terrain model that complements EGM2008) providing the long-wavelength reference surface. Because these RTM elevations imply most of the gravity field signal beyond spherical harmonic degree of 2,160, they can be used to augment EGM2008 vertical deflection predictions in the very high spherical harmonic degrees. In two mountainous test areas-the German and the Swiss Alps-the combined use of EGM2008 and RTM data was successfully tested at 223 stations with high-precision astrogeodetic vertical deflections from recent zenith camera observations (accuracy of about 0.1 arc seconds) available. The comparison of EGM2008 vertical deflections with the ground-truth astrogeodetic observations shows root mean square (RMS) values (from differences) of 3.5 arc seconds for ξ and 3.2 arc seconds for η, respectively. Using a combination of EGM2008 and RTM data for the prediction of vertical deflections considerably reduces the RMS values to the level of 0.8 arc seconds for both vertical deflection components, which is a significant improvement of about 75%. Density anomalies of the real topography with respect to the residual model topography are one factor limiting the accuracy of the approach. The proposed technique for vertical deflection predictions is based on three publicly available data sets: (1) EGM2008, (2) DTM2006.0 and (3) SRTM elevation data. This allows replication of the approach for improving the accuracy of EGM2008 vertical deflection predictions in regions with a rough topography or for improved validation of EGM2008 and future high-degree spherical harmonic models by means of independent ground truth data. © Springer-Verlag 2009.
Bennett D.,Curtin University Australia
Australian Geographer | Year: 2010
It is well known that a pilgrimage overseas can be crucial to the career development of specialist creative artists. All too often, however, the pilgrimage becomes a permanent migration. Significantly, the loss of this creative talent is not limited to the national level. The dominance of cities as the centres of Australia's knowledge-based economy leads also to migration of creative artists from regional centres and from smaller cities such as Perth, lessening the potential for those regions to attract and retain creative and innovative people. Given the globalised nature of the cultural industries and the emergence of new technologies, this study of Western Australian creative artists considers whether migration loss could be repositioned as cultural gain. Initial results suggest that spatial separation due to geographic isolation is particularly problematic for Western Australian creative artists both within the regions and the metropolitan area. Despite participants' strong personal connections with Western Australia, artistic connections were tenuous and artistic involvement was negligible. Implications include the need to actively engage with creative migrants by fostering their continued involvement in the cultural life of cities and regions. © 2010 Geographical Society of New South Wales Inc.
Sanders M.R.,University of Queensland |
Mazzucchelli T.G.,University of Queensland |
Mazzucchelli T.G.,Curtin University Australia
Clinical Child and Family Psychology Review | Year: 2013
The capacity for a parent to self-regulate their own performance is argued to be a fundamental process underpinning the maintenance of positive, nurturing, non-abusive parenting practices that promote good developmental and health outcomes in children. Deficits in self-regulatory capacity, which have their origins in early childhood, are common in many psychological disorders, and strengthening self-regulation skills is widely recognised as an important goal in many psychological therapies and is a fundamental goal in preventive interventions. Attainment of enhanced self-regulation skills enables individuals to gain a greater sense of personal control and mastery over their life. This paper illustrates how the self-regulatory principles can be applied to parenting and family-based interventions at the level of the child, parent, practitioner and organisation. The Triple P-Positive Parenting Program, which uses a self-regulatory model of intervention, is used as an example to illustrate the robustness and versatility of the self-regulation approach to all phases of the parent consultation process. © 2013 Springer Science+Business Media New York.
Winstock A.R.,Kings College London |
Barratt M.J.,Curtin University Australia
Drug and Alcohol Dependence | Year: 2013
Background: The last decade has seen the appearance of myriad novel psychoactive substances with diverse effect profiles. Synthetic cannabinoids are among the most recently identified but least researched of these substances. Methods: An anonymous online survey was conducted in 2011 using a quantitative structured research tool. Missing data (median 2%) were treated by available-case analysis. Results: Of 14,966 participants, 2513 (17%) reported use of synthetic cannabis. Of these, 980 (41% of 2417) reported its use in the last 12 months. Almost all recent synthetic cannabis users (99% of 975) reported ever use of natural cannabis. Synthetic cannabis reportedly had both a shorter duration of action (. z=. 17.82, p<. .001) and quicker time to peak onset of effect (. z=. -9.44, p<. .001) than natural cannabis. Natural cannabis was preferred to synthetic cannabis by 93% of users, with natural cannabis rated as having greater pleasurable effects when high (. t(930). =. -37.1, p<. .001, d=. -1.22) and being more able to function after use (. t(884). =. -13.3, p<. .001, d=. -0.45). Synthetic cannabis was associated with more negative effects (. t(859). =. 18.7, p<. .001, d=. 0.64), hangover effects (. t(854). =. 6.45, p<. .001, d=. 0.22) and greater paranoia (. t(889). =. 7.91, p<. .001, d=. 0.27). Conclusions: Users report a strong preference for natural over synthetic cannabis. The latter has a less desirable effect profile. Further research is required to determine longer term consequences of use and comparative dependence potential. © 2013 .
Li Z.-X.,Curtin University Australia |
Evans D.A.D.,Yale University
Geology | Year: 2011
Previous paleomagnetic work has appeared to demand the breakup of southwest United States-East Antarctic (SWEAT) type Rodinia reconstructions before ca. 750 Ma, significantly earlier than the stratigraphic record of rift-drift transition between 715 Ma and 650 Ma. Here we reanalyze Australian paleomagnetic and regional tectonic data to produce a model in which the Precambrian Australian continent had a slightly different configuration before the breakup of Rodinia. A cross-continental megashear zone developed along the Paterson and Petermann orogens at ca. 650-550 Ma, during or after the breakup of Rodinia, manifested as an ~40° clockwise rotation of the South and West Australian cratons relative to the North Australian craton around a vertical axis in Central Australia. This model reconciles major paleomagnetic discrepancies within Australia, and allows for a longer lifespan of SWEAT-like reconstructions of Rodinia that are consistent with the Neoproterozoic stratigraphic records of Australia and Laurentia. © 2011 Geological Society of America.
Ferrante A.,University of Padua |
Ntogramatzidis L.,Curtin University Australia
Automatica | Year: 2014
The purpose of this paper is to investigate the role that the so-called constrained generalized Riccati equation plays within the context of continuous-time singular linear-quadratic (LQ) optimal control. This equation has been defined following the analogy with the discrete-time setting. However, while in the discrete-time case the connections between this equation and the linear-quadratic optimal control problem has been thoroughly investigated, to date very little is known on these connections in the continuous-time setting. This note addresses this point. We show, in particular, that when the continuous-time constrained generalized Riccati equation admits a solution, the corresponding linear-quadratic problem admits an impulse-free optimal control. We also address the corresponding infinite-horizon LQ problem for which we establish a similar result under the additional constraint that there exists a control input for which the cost index is finite. © 2014 Elsevier Ltd. All rights reserved.
Omidi H.,Curtin University Australia |
Sathasivan A.,University of Western Sydney
International Biodeterioration and Biodegradation | Year: 2013
Temperature is one of the important parameters which can significantly effect on the activity/selection of microorganism and subsequently on the reactor's performance. Two microbial electrolysis cells (MECs) were operated at different temperature settings with acetate as a carbon source. On average, COD removal rates of 16.8, 24.7, 34.0, 36.2 and 18.1mg/l/h were recorded at 25, 29, 30, 31 and 35°C, respectively. The results of volatile suspended solids analysis indicated that biomass concentration continued to drop at all temperatures, but the drop was the lowest at 30°C. Consideration of biomass drop and specific COD removal rate showed 31°C as the optimum temperature. These significant results imply that effect of temperature and change in biomass concentration should be considered in future experiments when expressing the removal rates. © 2013 Elsevier Ltd.
Durey A.,Curtin University Australia
Australian and New Zealand Journal of Public Health | Year: 2010
Objective: This paper discusses whether educating health professionals and undergraduate students in culturally respectful health service delivery is effective in reducing racism, improving practice and lessening the disparities in health care between Aboriginal and non-Aboriginal Australians. Approach: The paper supports the concept of race as a social construction that is discursively produced and reproduced. Studies on the effectiveness of crosscultural education for undergraduate students and health professionals to reduce racism and deliver culturally respectful health care to indigenous or minority populations are examined for evidence of sustained improvements to practice. Conclusion: Programs in culturally respectful health care delivery can lead to short-term improvements to practice. Sustained change is more elusive as few programs conducted long-term evaluations. Long-term evaluation of programs in culturally respectful health care delivery is necessary to identify whether early changes to behavior and practices are sustained. Strategies linking policies to practice to reduce health disparities between Aboriginal and non-Aboriginal Australians are also needed. Implications: Confronting the effects of racism in health services towards Aboriginal Australians is a priority requiring a multi-tiered commitment to strategies linking policy to practice to reduce health disparities between Aboriginal and non- Aboriginal Australians. Part of this strategy includes preparing undergraduates and health professionals for culturally respectful health care with education programs that are evaluated for long-term improvements to practice. © 2010 The Authors. Journal Compilation.
Pearce W.M.,James Cook University |
Williams C.,Curtin University Australia
International Journal of Speech-Language Pathology | Year: 2013
Speech-language pathologists experience uncertainty about how to interpret standardized assessment results for Indigenous Australian children. There are risks for inappropriate diagnosis: both over- and under-diagnosis of language impairment may occur due to a convergence of linguistic features which causes difficulty in distinguishing between impairment and difference. While the literature suggests that standardized assessments are inappropriate for Indigenous Australian children, there is an absence of empirical documentation to show how Indigenous children perform on standardized tests of language ability. This study examined the performance of 19 Indigenous Australian children, aged 8;01-13;08, from one school on the Clinical Evaluation of Language Fundamentals, Fourth Edition, Australian Standardized Edition. Standardized scores were compared with teacher ratings of children's oral language skills. Analysis showed poor alignment between teacher ratings and language assessment, and assessment scores were negatively influenced by features of Aboriginal English. Children rated with above average language skills presented with different linguistic profiles from the children rated with average and below average language abilities. The inappropriateness of current standardized language assessments for Indigenous children and the need for further research to guide appropriate assessment are discussed. © 2013 The Speech Pathology Association of Australia Limited.
Shafiee S.,University of Queensland |
Topal E.,Curtin University Australia
Resources Policy | Year: 2010
The global gold market has recently attracted a lot of attention and the price of gold is relatively higher than its historical trend. For mining companies to mitigate risk and uncertainty in gold price fluctuations, make hedging, future investment and evaluation decisions, depend on forecasting future price trends. The first section of this paper reviews the world gold market and the historical trend of gold prices from January 1968 to December 2008. This is followed by an investigation into the relationship between gold price and other key influencing variables, such as oil price and global inflation over the last 40 years. The second section applies a modified econometric version of the long-term trend reverting jump and dip diffusion model for forecasting natural-resource commodity prices. This method addresses the deficiencies of previous models, such as jumps and dips as parameters and unit root test for long-term trends. The model proposes that historical data of mineral commodities have three terms to demonstrate fluctuation of prices: a long-term trend reversion component, a diffusion component and a jump or dip component. The model calculates each term individually to estimate future prices of mineral commodities. The study validates the model and estimates the gold price for the next 10 years, based on monthly historical data of nominal gold price. © 2010 Elsevier Ltd.
Hagger M.S.,Curtin University Australia |
Luszczynska A.,University of Colorado at Colorado Springs |
Luszczynska A.,University of the Humanities
Applied Psychology: Health and Well-Being | Year: 2014
The purpose of this paper is to provide an overview of the literature on two planning intervention techniques in health behaviour research, implementation intentions and action planning, and to develop evidence-based recommendations for effective future interventions and highlight priority areas for future research. We focused our review on four key areas: (1) definition and conceptualisation; (2) format and measurement; (3) mechanisms and processes; and (4) design issues. Overall, evidence supports the effectiveness of planning interventions in health behaviour with advantages including low cost and response burden. There is, however, considerable heterogeneity in the effects across studies and relatively few registered randomised trials that include objective behavioural measures. Optimally effective planning interventions should adopt "if-then" plans, account for salient and relevant cues, include examples of cues, be guided rather than user-defined, and include boosters. Future studies should adopt randomised controlled designs, report study protocols, include fidelity checks and relevant comparison groups, and adopt long-term behavioural follow-up measures. Priority areas for future research include the identification of the moderators and mediators of planning intervention effects. Future research also needs to adopt "best practice" components of planning interventions more consistently to elucidate the mechanisms and processes involved. © 2013 The International Association of Applied Psychology.
Iglauer S.,Curtin University Australia |
Ferno M.A.,University of Bergen |
Shearing P.,University College London |
Blunt M.J.,Imperial College London
Journal of Colloid and Interface Science | Year: 2012
We imaged an oil-wet sandstone at residual oil saturation (S or) conditions using X-ray micro-tomography with a nominal voxel size of (9μm) 3 and monochromatic light from a synchrotron source. The sandstone was rendered oil-wet by ageing with a North Sea crude oil to represent a typical wettability encountered in hydrocarbon reservoirs. We measured a significantly lower S or for the oil-wet core (18.8%) than for an analogue water-wet core (35%). We analysed the residual oil cluster size distribution and find consistency with percolation theory that predicts a power-law cluster size distribution. We measure a power-law exponent τ=2.12 for the oil-wet core which is higher than τ for the water-wet system (τ=2.05), indicating fewer large clusters in the oil-wet case. The clusters are rough and sheet-like consistent with connectivity established through layers in the pore space and occupancy of the smaller pores; in contrast the clusters for water-wet media occupy the centres of the larger pores. These results imply less trapping of oil, but with a greater surface area for dissolution. In carbon storage applications, this suggests that in CO 2-wet systems, capillary trapping is less significant, but that there is a large surface area for dissolution and reaction. © 2012 Elsevier Inc.
Kowalczyk P.,Curtin University Australia
Physical Chemistry Chemical Physics | Year: 2012
Combining experimental knowledge with molecular simulations, we investigated the adsorption and separation properties of double-walled carbon nanotubes (DWNTs) against flue/synthetic gas mixture components (e.g. CO 2, CO, N 2, H 2, O 2, and CH 4) at 300 K. Except molecular H 2, all studied nonpolar adsorbates assemble into single-file chain structures inside DWNTs at operating pressures below 1 MPa. Molecular wires of adsorbed molecules are stabilized by the strong solid-fluid potential generated from the cylindrical carbon walls. CO 2 assembly is formed at very low operating pressures in comparison to all other studied nonpolar adsorbates. The adsorption lock-and-key mechanism results from perfect fitting of rod-shaped CO 2 molecules into the cylindrical carbon pores. The enthalpy of CO 2 adsorption in DWNTs is very high and reaches 50 kJ mol -1 at 300 K and low pore concentrations. In contrast, adsorption enthalpy at zero coverage is significantly lower for all other studied nonpolar adsorbates, for instance: 35 kJ mol -1 for CH 4, and 14 kJ mol -1 for H 2. Applying the ideal adsorption solution theory, we predicted that the internal pores of DWNTs have unusual ability to differentiate CO 2 molecules from other flue/synthetic gas mixture components (e.g. CO, N 2, H 2, O 2, and CH 4) at ambient operating conditions. Computed equilibrium selectivity for equimolar CO 2-X binary mixtures (where X: CO, N 2, H 2, O 2, and CH 4) is very high at low mixture pressures. With an increase in binary mixture pressure, we predicted a decrease in equilibrium separation factor because of the competitive adsorption of the X binary mixture component. We showed that at 300 K and equimolar mixture pressures up to 1 MPa, the CO 2-X equilibrium separation factor is higher than 10 for all studied binary mixtures, indicating strong preference for CO 2 adsorption. The overall selective properties of DWNTs seem to be superior, which may be beneficial for potential industrial applications of these novel carbon nanostructures. © the Owner Societies 2012.
Rieck A.,Curtin University Australia |
Pettigrew S.,University of Western Australia
Quality in Primary Care | Year: 2013
Background Community pharmacists (CPs) have been changing their role to focus on patient-centred services to improve the quality of chronic disease management (CDM) in primary care. However, CPs have not been readily included in collaborative CDM with other primary care professionals such as physicians. There is little understanding of the CP role change and whether it affects the utilisation of CPs in primary care collaborative CDM. Aim To explore physician and CP perceptions of the CP's role in Australian primary care and how these perceptions may influence the quality of physician/CP CDM programmes. Methods Data were collected from physicians and CPs using semi-structured interviews. A qualitative methodology utilising thematic analysis was employed during data analysis. Qualitative methodology trustworthiness techniques, negative case analysis and member checking were utilised to substantiate the resultant themes. Results A total of 22 physicians and 22 CPs were interviewed. Strong themes emerged regarding the participant perceptions of the CP's CDM role in primary care. The majority of interviewed physicians perceived that CPs did not have the appropriate CDM knowledge to complement physician knowledge to provide improved CDM compared with what they could provide on their own. Most of the interviewed CPs expressed a willingness and capability to undertake CDM; however, they were struggling to provide sustainable CDM in the business setting within which they function in the primary care environment. Conclusions Role theory was selected as it provided the optimum explanation of the resultant themes. First, physician lack of confidence in the appropriateness of CP CDM knowledge causes physicians to be confused about the role CPs would undertake in a collaborative CDM that would benefit the physicians and their patients. Thus, by increasing physician awareness of CP CDM knowledge, physicians may see CPs as suitable CDM collaborators. Second, CPs are experiencing role conflict and stress in trying to change their role. Strengthening the service business model may reduce these CP role issues and allow CPs to reach their full potential in CDM and improve the quality of collaborative CDM in Australian primary care. © 2013 Radcliffe Publishing.
Abu-Siada A.,Curtin University Australia
IET Science, Measurement and Technology | Year: 2011
Furans are the major degradation of insulating study in transformer oil. Hence, the concentration of furans in oil can be used as a good indicator of study deterioration. Furan concentration in transformer oil is currently measured using high-performance liquid chromatography or gas chromatography-mass spectrometry. Both methods provide accurate and reliable results in detecting furan concentration. However, the two methods need very expensive equipment and take a long time to perform the test on oil samples that should be chemically treated before conducting the test. Moreover, both methods require an expert to perform the test and to interpret its results. This study introduces a novel technique for detecting furan concentration in transformer oil through measuring oil spectral response. The ultraviolet-to-visible spectral response of transformer oil can be measured instantly with relatively cheap equipment and does not need an expert person to conduct the test. Results show that there is a good correlation between oil spectral response and its furan contents. The study introduces two approaches using expert systems to estimate the relationship between furan concentration and spectral response of transformer oil; they are gene expression programming and fuzzy logic. © 2011 The Institution of Engineering and Technology.
Feng H.,Tsinghua University |
Soria R.,Curtin University Australia
New Astronomy Reviews | Year: 2011
Ultraluminous X-ray sources (ULXs) are accreting black holes that may contain the missing population of intermediate mass black holes or reflect super-Eddington accretion physics. Ten years of Chandra and XMM-Newton observations of ULXs, integrated by multiband studies of their counterparts, have produced a wealth of observational data and phenomenological classifications. We review the properties of their host galaxies, list popular spectral models and implications for standard and supercritical accretion physics, demonstrate how X-ray timing of these objects places constraints on their masses. We also review multiwavelength studies of ULXs, including the optical emission of the binary system and nebulosity around them. We summarize that three classes of black holes could power ULXs: normal stellar mass black holes (~10M⊙), massive stellar black holes (≲100M⊙), and intermediate mass black holes (102-104M⊙). We collect evidence for the presence of these three types of compact objects, including caveat of each interpretation, and briefly review their formation processes. © 2011 Elsevier B.V.
Gourlay T.P.,Curtin University Australia
Journal of Engineering Mathematics | Year: 2011
This article traces the contributions of Prof. E. O. Tuck to the field of mathematical ship-squat prediction. The review expands on Tuck's own review of his early work (Ann. Rev. Fluid Mech. 10:33, 1978) and describes the use of his formulae in modern squat-prediction methods. A method for calculating Tuck's sinkage and trim coefficients using easily obtainable ship parameters is also described. © 2010 Springer Science+Business Media B.V.
Tan Y.,Curtin University Australia
Corrosion Science | Year: 2011
Corrosion measurement in highly resistive and inhomogeneous media can be very challenging due to practical difficulties in setting up and maintaining testing cells and sensors, problems associated with IR potential drops and nonuniform polarisation current distribution, and limitations associated with localised corrosion monitoring and detection. Many technological innovations have been made over the past decade to address these issues with reports scattered throughout the literature. This paper provides an overview of innovative experimental methods designed for corrosion testing and monitoring in highly-resistive and inhomogeneous media, with particular focus on localised corrosion measurement using electrode array and electrochemical noise techniques. © 2011 Elsevier Ltd.
Dolzhenko A.V.,Curtin University Australia
Heterocycles | Year: 2011
The present review summarizes information on the synthetic approaches to thiazolo[3,2-a][1,3,5]triazines and polyfused systems bearing this heterocyclic core since the first report on this structure in 1887. The methods allowing access to the heterocyclic systems comprising isomeric thiazolo[3,4-a][1,3,5] triazine scaffold are also included in the review. Data concerning potential applications of the thiazolo[1,3,5]triazines, particularly as biologically active agents are discussed. © 2011.
Love P.,Curtin University Australia
Journal of Engineering, Design and Technology | Year: 2011
Purpose: Adaptive re-use enables a building to suit new conditions. It is a process that reaps the benefit of the embodied energy and quality of the original building in a sustainable manner. Initiatives to improve the sustainability of buildings have tended to focus on new construction projects rather than existing ones. One reason is the tendency to regard old buildings as products with a limited useful life that have to be eventually discarded and demolished. Much of the existing building stock will still be in use for another 100 years. Thus, there is a need to develop policy and strategies that encourage adaptive re-use and the ongoing sustainability of building stock. The purpose of this paper is to provide a comprehensive review of the factors influencing the decision to adopt an adaptive re-use strategy. Design/methodology/approach: Adaptive re-use is beginning to receive attention, yet there is a lack of consensus as to whether it is an appropriate strategy for meeting the changing needs and demands of developers, occupiers and owners for existing building stock. Considering the limited published research on adaptive re-use in buildings, particularly in the context of sustainability, a comprehensive review of the normative literature is undertaken to determine the factors influencing the decision-making process for its use. Findings: It is revealed that the major drivers for adaptive focus on lifecycle issues, changing perceptions of buildings, and governmental incentives. The barriers to re-use, on the other hand, include a perception of increased maintenance costs, building regulations, inertia of development criteria and the inherent risk and uncertainty associated with older building stock. The identification of drivers and barriers has enabled a balanced view of the adaptive re-use debate to be presented. Research limitations/implications: The paper concludes that more empirical research is required to examine the role of adaptive re-use in the context of its contribution to sustainability if it is to become an effective strategy that drives the formulation of public policy for addressing the issues associated with existing building stock. Practical implications: The research identifies key adaptive re-use issues that need to be addressed by policy makers, developers and owners during the formative stages of the design process so that efforts toward sustainability can be ameliorated. Addressing a building's adaptive re-use will significantly reduce whole life costs, waste and lead to the improved building functionality. Originality/value: This paper provides policy makers and key decision makers with the underlying factors that need to be considered when implementing an adaptive re-use policy as part of their sustainability strategy. © Emerald Group Publishing Limited.
Ferrante A.,University of Padua |
Ntogramatzidis L.,Curtin University Australia
IEEE Transactions on Automatic Control | Year: 2012
In this note it is shown that the main result of , concerning a characterization of a pair of structural invariant subspaces associated with the extended symplectic system, is a particular case of a result presented in and within a more general and rigorous context. We also analyse the proof of the main result of , and the way such result is used to accomodate the boundary conditions in the solution of a finite-horizon linear quadratic optimal control problem. © 2006 IEEE.
Fraser S.,Curtin University Australia
International Journal of Drug Policy | Year: 2015
Concepts of addiction differ across time and place. This article is based on an international research project currently exploring this variation and change in concepts of addiction, in particular in the field of alcohol and other drug (AOD) use. Taking AOD policy in Australia and Canada as its empirical focus, and in-depth interviews with policy makers, service providers and advocates in each country as its key method (N = 60), the article compares the addiction concepts articulated by professionals working in each setting. Drawing on Bruno Latour's theoretical work on the body and his proposal for a better science based on the 'articulation of differences', it explores the accounts of addiction offered across the Australian and Canadian project sites, identifying a shared dynamic in all: the juggling of difference and unity in discussions of the nature of addiction, its composite parts and how best to respond to it. The article maps two simultaneous trajectories in the data - one moving towards difference in participants' insistence on the multitude and diversity of factors that make up addiction problems and solutions, and the other towards unity in their tendency to return to narrow disease models of addiction in uncomfortable, sometimes dissonant, strategic choices. As I will argue, the AOD professionals interviewed for my project operate in two modes treated as distinct in Latour's proposal: in turning to reifying disease labels of addiction they take for granted, and work within, a 'universe of essences', but in articulating the multiplicity and diversity of addiction, they grope towards a vision of a 'multiverse of habits'. The article concludes by addressing this tension directly, scrutinising its practical implications for the development of policy and delivery of services in the future, asking how new thinking, and therefore new opportunities, might be allowed to emerge. © 2015.
Hirt C.,Curtin University Australia
Marine Geodesy | Year: 2013
We apply the residual terrain modeling (RTM) technique for gravity forward-modeling to successfully improve high-resolution global gravity fields at short spatial scales in coastal zones. The RTM scheme is combined with the concept of rock-equivalent topography, allowing to use a single uniform constant mass-density in the RTM forward-modeling, both at land and sea. SRTM30_PLUS bathymetry is merged with higher-resolution SRTM V4.1 land topography, and expanded into spherical harmonics to degree 2160, yielding a new and consistent high-degree RTM reference surface. The forward-modeling performance is demonstrated in coastal zones of Greece and Canada using ground-truth vertical deflections, gravity from land and shipborne gravimetry, and geoid heights from GPS/leveling, with improvements originating from bathymetry clearly identified. We demonstrate that the SRTM30_PLUS bathymetry carries information on gravity field structures at spatial scales less than 5 arc minutes, which can be used to augment EGM2008 in (rugged) coastal zones, both over land and marine areas. This may be of value (i) to partially reduce the signal omission error in EGM2008/GOCE-based height transfer in areas devoid of dense gravity data, (ii) to fill the gap between land gravity and shipborne gravity along rugged coastlines, and (iii) for the development of next-generation altimetric gravity fields. © 2013 Copyright Taylor and Francis Group, LLC.
Zusman M.,Curtin University Australia
Journal of Multidisciplinary Healthcare | Year: 2013
Recent figures show that there has been no change in the upward trend of direct and indirect costs for the largely benign symptom of low back pain in Western societies. This is despite greater understanding and the recommendation of a much more conservative and independent approach to its management. Moreover, in recent years, several large-scale education programs that aim to bring knowledge of the public (including general practitioners) more in line with evidence-based best practice were carried out in different countries. The hope was that the information imparted would change beliefs, ie, dysfunctional patient behavior and biomedical practice on the part of clinicians. However, these programs had no influence on behavior or costs in three out of the four countries in which they were implemented. It is argued that one reason for the overall lack of success is that it is extremely difficult to alter the potentially disabling belief among the lay public that low back pain has a structural mechanical cause. An important reason for this is that this belief continues to be regularly reinforced by the conditions of care of a range of "hands-on" providers, for whom idiosyncratic variations of that view are fundamental to their professional existence. © 2013 Zusman, publisher and licensee Dove Medical Press Ltd.
Van Kranendonk M.J.,University of New South Wales |
Van Kranendonk M.J.,Macquarie University |
Kirkland C.L.,Geological Survey of Western Australia |
Kirkland C.L.,Curtin University Australia
Geology | Year: 2013
The rate of growth of the continental crust is controversial. We present an evaluation of time-constrained analyses of oxygen isotopes in zircon grains and incompatible element (Zr, Th) concentrations in magmatic rocks to test for variations in the degree of crustal recycling through geological time. The data indicate a rise in these geochemical proxies from ca. 3.0 Ga to a statistically significant peak at 1.2-1.1 Ga during the amalgamation of supercontinent Rodinia, and a decrease thereafter. When combined with other geological and geophysical observations, the data are interpreted as a consequence of an unprecedented level of crustal recycling and sediment subduction during Rodinia assembly, arising from a "Goldilocks" (i.e., just right) combination of larger, thicker plates on a warmer Earth with more rapid continental drift relative to modern Earth. The subsequent decrease in 18O, Zr, and Th measurements is interpreted to refl ect decreasing drift rates on a cooling Earth. © 2013 Geological Society of America.
Lewin G.,Curtin University Australia |
Vandermeulen S.,Silver Chain
Health and Social Care in the Community | Year: 2010
The Home Independence Program (HIP) is a short-term restorative programme targeted at older home-care clients, who do not have a diagnosis of dementia, when they are first referred for assistance or when they are referred for additional services because their needs have increased. This study compared the outcomes for individuals who participated in HIP with those of individuals who received 'usual' home-care services. The study was conducted in metropolitan Perth, Western Australia, between 2001 and 2003, when HIP was being trialled as a service in just one region. One hundred clients were recruited into each group and were visited at home on three occasions - service start and at 3 months and 1 year. Standardised outcome measures were used to measure functional dependency, morale, confidence in performing everyday activities without falling and functional mobility. Service outcomes were also examined at 3 months and 1 year. The HIP group showed improvements on all personal outcome measures compared with the control group. These improvements were, except for the morale scale, significantly associated with group assignment even when baseline differences between the groups were adjusted for. As regards service outcomes, the odds of the individuals who received HIP still requiring services was 0.07 (95% CI = 0.03-0.15, P < 0.001) times those for the individuals in the control group at 3 months and 0.14 times at 12 months (95% CI = 0.07-0.29, P < 0.001). The results of this study supported the hypothesis that older individuals referred for home care who participated in a programme to promote their independence had better individual and service outcomes than individuals who received usual home care. © 2009 Blackwell Publishing Ltd.
Sanguinetti L.,University of Pisa |
D'Amico A.A.,University of Pisa |
Rong Y.,Curtin University Australia
IEEE Journal on Selected Areas in Communications | Year: 2012
The remarkable promise of multiple-input multiple-output (MIMO) wireless channels has motivated an intense research activity to characterize the theoretical and practical issues associated with the design of transmit (source) and receive (destination) processing matrices under different operating conditions. This activity was primarily focused on point-to-point (single-hop) communications but more recently there has been an extensive work on two-hop or multi-hop settings in which single or multiple relays are used to deliver the information from the source to the destination. The aim of this tutorial is to provide an up-to-date overview of the fundamental results and practical implementation issues in designing amplify-and-forward MIMO relay systems. © 2012 IEEE.
Shaikh F.U.A.,Curtin University Australia
Materials and Design | Year: 2013
This paper reports the newly developed ductile fibre reinforced geopolymer composite (DFRGC) exhibiting deflection hardening and multiple cracking behaviour. The binder of the above composite is different from that used in conventional cement based system. The class F fly ash is used instead of Portland cement in DFRGC and is activated by alkaline liquids (sodium hydroxide and sodium silicate). In this study, two types of fibres namely steel (ST) and polyvinyl alcohol (PVA) fibres are used in mono as well as in ST-PVA hybrid form, with a total volume fraction of 2%. The deflection hardening behaviour of newly developed DFRGC is also compared with that of conventional ductile fibre reinforced cementitious composites (DFRCC). The effects of two different sizes of sand (1.18mm, and 0.6mm) and sand/binder ratios of 0.5 and 0.75 on the deflection hardening and multiple cracking behaviour of both DFRGC and DFRCC are also evaluated. Results revel that the deflection hardening and multiple cracking behaviour is achieved in geopolymer based DFRGC similar to that of cement based system. For a given sand size and sand content, comparable deflection hardening behaviour, ultimate flexural strength and the deflection at peak load are observed in both cement and geopolymer based composites irrespective of fibre types and combination. The deflection hardening behaviour of DFRGC is also confirmed by the calculated toughness index values of I20>20. The scanning electron microscope (SEM) study shows no degradation of PVA and steel fibres in the geopolymer matrix. However, the bond of PVA fibre with geopolymer matrix is found to be higher than that with cement matrix as evidenced in the SEM pictures. An opposite trend is observed with steel fibre. The proposed development exhibit a significant benefit for the use of geopolymer based DFRGC over cement based system as the former one is green in terms of no cement use. © 2013 Elsevier Ltd.
Sarker P.K.,Curtin University Australia |
Haque R.,SGS Australia |
Ramgolam K.V.,Shire of Kalamunda
Materials and Design | Year: 2013
Use of fly ash based geopolymer as an alternative binder can help reduce CO2 emission of concrete. The binder of geopolymer concrete (GPC) is different from that of ordinary Portland cement (OPC) concrete. Thus, it is necessary to study the effects of the geopolymer binder on the behaviour of concrete. In this study, the effect of the geopolymer binder on fracture characteristics of concrete has been investigated by three point bending test of RILEM TC 50 - FMC type notched beam specimens. The peak load was generally higher in the GPC specimens than the OPC concrete specimens of similar compressive strength. The failure modes of the GPC specimens were found to be more brittle with relatively smooth fracture planes as compared to the OPC concrete specimens. The post-peak parts of the load-deflection curves of GPC specimens were steeper than that of OPC concrete specimens. Fracture energy calculated by the work of fracture method was found to be similar in both types of concrete. Available equations for fracture energy of OPC concrete yielded conservative estimations of fracture energy of GPC. The critical stress intensity factor of GPC was found to be higher than that of OPC concrete. The different fracture behaviour of GPC is mainly because of its higher tensile strength and bond strength than OPC concrete of the same compressive strength. © 2012 Elsevier Ltd.
Wills-Johnson N.,Curtin University Australia
Environment, Development and Sustainability | Year: 2010
Environmentally sustainable development is one of the key challenges faced by societies today. Yet it is not a new challenge; throughout history, societies have faced the need to live within environmental constraints. Some have done so well, and some poorly. One society which did well for tens of thousands of years is that of Aboriginal Australia. This paper explores some lessons from Aboriginal Australia which have resonance in the modern world and shows that countries which have learned those lessons are in fact more sustainable than those which have not. It thus suggests that there is much that the pantheon of human experience can teach the modern world as it endeavours to create a sustainable future. © Springer Science + Business Media, B.V. 2010.
Schofield M.J.,La Trobe University |
Grant J.,Curtin University Australia
BMC Psychiatry | Year: 2013
Background: Mental health professionals face unique demands and stressors in their work, resulting in high rates of burnout and distress. Clinical supervision is a widely adopted and valued mechanism of professional support, development, and accountability, despite the very limited evidence of specific impacts on therapist or client outcomes. The current study aims to address this by exploring how psychotherapists develop competence through clinical supervision and what impact this has on the supervisees' practice and their clients' outcomes. This paper provides a rationale for the study and describes the protocol for an in-depth qualitative study of supervisory dyads, highlighting how it addresses gaps in the literature. Methods/Design: The study of 16-20 supervisor-supervisee dyads uses a qualitative mixed method design, with two phases. In phase one, supervisors who are nominated as expert by their peers are interviewed about their supervision practice. In phase two, supervisors record a supervision session with a consenting supervisee; interpersonal process recall interviews are conducted separately with supervisor and supervisee to reflect in depth on the teaching and learning processes occurring. All interviews will be transcribed, coded and analysed to identify the processes that build competence, using a modified form of Consensual Qualitative Research (CQR) strategies. Using a theory-building case study method, data from both phases of the study will be integrated to develop a model describing the processes that build competence and support wellbeing in practising psychotherapists, reflecting the accumulated wisdom of the expert supervisors.Discussion: The study addresses past study limitations by examining expert supervisors and their supervisory interactions, by reflecting on actual supervision sessions, and by using dyadic analysis of the supervisory pairs. The study findings will inform the development of future supervision training and practice and identify fruitful avenues for future research. © 2013 Schofield and Grant; licensee BioMed Central Ltd.
Smith K.,Curtin University Australia
Library Hi Tech News | Year: 2011
Purpose: The paper seeks to describe the establishment and progress of an online initiative: RIC - Researching the Information Commons. Design/methodology/approach: Who has really challenged and thought through in a research sense about the issues that surround the commons provision of information; a concept dear to the hearts of many of the world's librarians? This question leads to the development of a researcher networking initiative, represented on the web as RIC (http://infocommons.curtin.edu.au). Findings: The web site has a growing number of participants, not all working together, but who are interested in information commons matters from a research point of view. Research limitations/implications: RIC is a federated network of colleagues researching in this many faceted arena and it is slowly gathering momentum. Expressions of interest to join have been sought, and a web site has been developed. Practical implications: RIC will operate through: openness and feedback; shared decision making; diversity within the commons; honouring social and legal equity amongst its members; and fostering sociability within the commons. Social implications: The vision for the RIC Group is to nurture and mentor a community of researchers interested in matters relating to the information commons, by being in itself an information commons. Originality/value: The topic of information commons has considerable use and currency but there appears to be only one RIC. © Emerald Group Publishing Limited.
Davies A.,Curtin University Australia
Journal of Rural Studies | Year: 2011
The world's population is ageing, with forecasts predicting this ageing is likely to be particularly severe in the rural areas of more developed countries. These forecasts are developed from nationally aggregated census and survey data and assume spatial homogeneity in ageing. They also draw on narrow understandings of older people and construct the potential impact of ageing (such as increased dependence on the health care system) as negative. The construction and reinforcement of such stereotypes have obscured public policy debate about ageing and also the rural. This paper considered how, through using a mixed method approach, narrow understandings of rural ageing could be extended and refined. Using a case study of grey nomads in rural Australia, the strengths and weaknesses of various research approaches were reviewed. The investigation concluded that both quantitative and qualitative data could be used to extend contemporary understandings of rural population ageing and move constructions of this phenomenon beyond an impending rural crisis. © 2011 Elsevier Ltd.
Ruebsam W.,University of Kiel |
Schwark L.,University of Kiel |
Schwark L.,Curtin University Australia
Earth and Planetary Science Letters | Year: 2014
Early Toarcian (Jurassic; ~183 Ma) sediments recorded profound environmental changes, including mass extinction, global warming, marine transgression as well as widespread bottom water anoxia and organic matter accumulation on the Western Tethyan shelf. Enhanced organic matter accumulation was accompanied by a positive carbon isotope excursion (CIE) in pelagic carbonate, which marks the Toarcian Oceanic Anoxic Event. These environmental changes were accompanied by a major perturbation of the global carbon cycle, expressed by negative CIE, interrupting the positive trend. The duration of the carbon cycle perturbation is still debated, with estimates for the negative CIE range from ~200 to ~600 kyr. Here we present ultra high-resolution (<1 kyr) measurements of magnetic susceptibility and sediment color from a marine section located in the Lorraine Sub-Basin (NE Paris Basin) documenting Milankovitch-controlled fluctuations in depositional conditions that occurred superimposed onto the overall sea level evolution. Differences in the wavelength of the sedimentary cycles indicate variable sediment accumulation rates that mainly resulted from rapid sea level fluctuations. The most pronounced sea level rise that took place within the uppermost tenuicostatum zone resulted in a strong condensation of the basal Schistes Carton formation. Strong condensation can explain the discrepancy between durations previously calculated for the CIE placed at this stratigraphic interval. Our data support durations of ~900 kyr and ~600 kyr for the positive and negative CIE, respectively. The cyclostratigraphy-based timescale further proposes a duration of >555 kyr for the tenuicostatum zone and 1310 kyr for the serpentinum zone. The durations of the elegantulum and falciferum subzones can be estimated to ~790 kyr and ~520 kyr, respectively. A change in the orbital response from eccentricity- to obliquity-forcing, evident from other locations, is well-expressed in the Lorraine Sub-Basin and occurred within the CIE interval. The strong impact of the obliquity component in post-event deposits hints to processes most effective at high latitudes, such as the waxing and waning of polar ice. Paleogeographic features of the Western Tethyan shelf supported the tele-connection of higher to lower latitude processes via water exchange through the Viking Corridor. © 2014 Elsevier B.V.
Hirt C.,Curtin University Australia |
Hirt C.,TU Munich
Geophysical Research Letters | Year: 2014
Accurate knowledge of Antarctica's topography, bedrock, and ice sheet thickness is pivotal for climate change and geoscience research. Building on recent significant progress made in satellite gravity mapping with European Space Agency's Gravity field and Ocean Circulation Explorer (GOCE) mission, we here reverse the widely used approach of validating satellite gravity with topography and instead utilize the new GOCE gravity maps for novel evaluation of Bedmap1/2. Space-collected GOCE gravity reveals clear improvements in the Bedmap2 ice and bedrock data over Bedmap1 via forward modeled topographic mass and gravity effects at spatial scales of 400 to 80 km. Our study demonstrates GOCE's sensitivity for the subsurface mass distribution in the lithosphere and delivers independent evidence for Bedmap2's improved quality, reflecting new radar-derived ice thickness data. GOCE and Bedmap2 are combined to produce improved Bouguer gravity maps over Antarctica. We recommend incorporation of Bedmap2 in future high-resolution global topography and geopotential models and its use for detailed geoid modeling over Antarctica. © 2014. American Geophysical Union. All Rights Reserved.
de Oliveira B.I.R.,Curtin University Australia
Spinal Cord | Year: 2016
Study design:Quasi-experimental translational study with pre- and post-measures.Objectives:To determine the effects of the Spinal Cord Injury and Physical Activity in the Community (SCIPA Com) intervention on leisure-time physical activity (LTPA) and associated outcomes among participants with spinal cord injury (SCI).Setting:Young Men’s Christian Associations and community fitness centers, Australia and New Zealand.Methods:SCIPA Com consisted of three stages: (i) training exercise professionals via the Train the Trainers Spinal Cord Injury course; (ii) implementation of supervised physical activity programs twice a week for 30 to 60 min for 8 to 12 weeks; and (iii) follow-up assessments on health outcomes over 9 months. Participants with SCI were classified as active or inactive by baseline LTPA levels and linear mixed methods compared LTPA between groups over time.Results:Sixty-four community-dwelling participants with SCI completed customized physical activity programs. Compared with baseline, there were significant improvements in LTPA (26 min per day, 95% confidence interval (CI): 16.6–35.4; P<0.001), functional goals (2, 95% CI: 1.72–2.37; P<0.001), self-esteem (1.5, 95% CI: 0.72–2.27; P<0.001) and overall quality of life (P<0.05). Over time, LTPA participation was greater among the active compared with the inactive group, although LTPA levels among the inactive improved compared with baseline.Conclusions:Significant improvements in LTPA participation and health outcomes were observed, especially among inactive individuals with SCI. SCIPA Com is an ecologically valid intervention based on training and support provided to community exercise professionals who, although new to adapted training, delivered effective physical activity programs for those at risk of inactivity.Sponsorship:Transport Accident Commission (Project Number DP172) and the International Postgraduate Research Scholarship (IPRS), Curtin University.Spinal Cord advance online publication, 19 January 2016; doi:10.1038/sc.2015.235. © 2016 International Spinal Cord Society
Sevastopulo G.D.,Trinity College Dublin |
Barham M.,Curtin University Australia
Geological Magazine | Year: 2014
The Task Group charged with proposing the GSSP for the base of the Serpukhovian Stage (Mississippian, Lower Carboniferous) is likely to use the global First Appearance Datum (FAD) of the conodont Lochriea ziegleri in the lineage Lochriea nodosa - L. ziegleri for the definition and correlation of the base of the stage. It is important to establish that the FAD of L. ziegleri in different basins is penecontemporaneous. Ammonoids provide high-resolution biostratigraphy in the Late Mississippian but their use in international correlation is limited by provincialism. However, it is possible to assess the levels of diachronism of the First Occurrence Datum (FOD) of L. ziegleri in sections in NW Europe using ammonoid zones. Published conodont distribution in the Rhenish Slate Mountains of Germany show the FOD of L. ziegleri in the Emstites novalis Biozone (upper part of the P2c zone of the UK and Ireland) but L. ziegleri has also been reported as occurring in the Neoglyphioceras spirale Biozone (P1d zone). In the Yoredale Group of northern England, the FOD of L. ziegleri is in either the P1c or P1d zone. In NW Ireland, the oldest records of both L. nodosa and L. ziegleri are from the Lusitanoceras granosum Biozone (P2a). Although there is some discrepancy in the recorded levels of the FOD of L. ziegleri in NW Europe, this may be as a result of collection failure. The base of the Serpukhovian based on the FAD of Lochriea ziegleri will be in the middle of the Brigantian regional Substage. © Cambridge University Press 2013.
Fisher C.,University of Western Australia |
O'Connor M.,Curtin University Australia
Cancer Nursing | Year: 2012
Background: Breast cancer is the most commonly diagnosed cancer among women in Western Australia, with negative psychological impacts exacerbated for younger women. Many women survive 5 years following diagnosis, suggesting more young women and their families will be living with its ongoing effects for longer periods. Diagnosis and treatment impact a woman's identity as a mother, but limited research exists from the women's perspective. Objective: The aim of the study was to explore the impact of breast cancer on the identities of young women as "mothers." Methods: A qualitative research design using conversational in-depth interviews and guided by a social constructivist paradigm was used. In-depth interviews were undertaken with 8 young women who were living with breast cancer and had dependent children. Interviews were audiotaped, transcribed, and analyzed. Results: Biographical disruption as described by Bury provided the analytical framework for interpretation of data. Four themes, "diagnosis and disruption," "maintaining normality," "continuing the mothering role," and "experiencing survivorship," reflect women's experiences of identity reconstruction in the context of living with breast cancer. Conclusions: A breast cancer diagnosis precipitates complex changes in a woman's identity as a mother. A woman's postdiagnosis identity invariably integrates a changed prediagnosis identity and that of "breast cancer patient" and "survivor." The relationship between the 3 is dynamic and in constant tension. Implications for Practice: Routine practice should include acknowledgement that an identity as mother exists alongside "patient." Questions to women about children and any concerns and issues they may have should also be routine. Copyright © 2012 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Glasser L.,Curtin University Australia
Inorganic Chemistry | Year: 2014
Materials with the garnet crystal structure include silicate minerals of importance both in geology, on account of their use in geothermobarometry, and industrially as abrasives. As a consequence of the former, there is considerable published thermodynamic information concerning them. We here examine this thermodynamic information for end-member silicate garnets (some of which are synthetic since not all occur in nature) for consistencies and anomalies, using thermodynamic relations between thermodynamic properties that we have established over recent years. The principal properties of interest are formula volume, heat capacity, entropy, formation enthalpy (from which the Gibbs energy may be obtained), and isothermal compressibility. A significant observation is that the ambient-temperature heat capacities of the silicate garnets are rather similar, whereas their ambient-temperature entropies are roughly proportional to their formula volumes. Evaluation of their Debye temperatures implies that their vibrational contributions to heat capacity are fully excited at ambient temperatures. The relatively small isothermal compressibilities of these garnets is related to the rigidity of their constituent silicate tetrahedra. We here establish additive single-ion values for each of the thermodynamic properties, which may be applied in estimating corresponding values for related materials. © 2014 American Chemical Society.
MacLean S.,University of Melbourne |
MacLean S.,Center for Alcohol Policy Research |
Moore D.,Curtin University Australia
International Journal of Drug Policy | Year: 2014
Background: Young adults from across greater Melbourne are drawn to the city centre night time economy (NTE). There is some evidence that young adults who live in outer-suburbs are involved in higher rates of weekend night time assaults than their inner-urban peers, both as perpetrators and as victims. Using the notion of 'assemblages', this article explores outer-suburban people's participation in the affectively charged spaces of inner-city entertainment precincts to show that trouble in the NTE cannot be attributed to alcohol and other drugs alone. Methods: We provide a narrative analysis of interviews conducted in 2012 with 60 young adult drinkers aged 18-24, half of whom lived in an inner-city area and half in outer-suburbs. Results: More so for young adults from outer-suburbs than those who live closer to the city, going to the city is an event marked out as different from everyday life. Their sense of being 'hyped up' in the inner-city made different sets of practices possible, particularly in relation to drinking and being open to new engagements with friends and sexual partners. Participants also spoke, however, of discomfort, danger and fear. Violence was most likely to occur at points where people felt a dissonance between their heightened affective states and the spaces where they found themselves. Conclusion: In this analysis, outer-suburban young adults' positioning within the assemblages of the city centre NTE makes conflict and violence more likely for them. Efforts to improve NTE safety should maintain a focus on managing alcohol availability. Nonetheless additional strategies to decentralise the NTE, ensure better late night public transport to outer-suburbs or to support people to manage sudden affective shifts in NTE might also play a greater part in the overall effort. © 2014 Elsevier B.V.
Karousis N.,National Hellenic Research Foundation |
Suarez-Martinez I.,Curtin University Australia |
Ewels C.P.,University of Nantes |
Tagmatarchis N.,National Hellenic Research Foundation
Chemical Reviews | Year: 2016
Carbon nanohorns (sometimes also known as nanocones) are conical carbon nanostructures constructed from an sp2 carbon sheet. Nanohorns require no metal catalyst in their synthesis, and can be produced in industrial quantities. They provide a realistic and useful alternative to carbon nanotubes, and possibly graphene, in a wide range of applications. They also have their own unique behavior due to their specific conical morphology. However, their research and development has been slowed by several factors, notably during synthesis, they aggregate into spherical clusters ∼100 nm in diameter, blocking functionalization and treatment of individual nanocones. This limitation has recently been overcome with a new approach to separating these "dahlia-like" clusters into individual nanocones. In this review, we describe the structure, synthesis, and topology of carbon nanohorns, and provide a detailed review of nanohorn chemistry. © 2016 American Chemical Society.
Mujah D.,Curtin University Australia
Journal of Cleaner Production | Year: 2015
This study investigates the compressive strength of grout and how the filler effect of ground palm oil fuel ash (POFA) contributes to its strength. POFA derived from the palm oil fruit bunches (POFA-FB) and also from the kernels (POFA-K) were ground to two different particle sizes and used to replace Type I Portland cement at 0-40% by weight of binder to cast the grout samples. The compressive strengths of ground POFA grouts were determined at various ages between 7 and 60 days. The results showed that the compressive strength of grout reinforced with POFA-K was much more noticeable as compared to that of POFA-FB. It is also reported that small particles of ground POFA promoted a filler effect that helped to increase the compressive strength of grouts. In contrast, larger particles of ground POFA decrease the value of compressive strength due to the development of more voids in the microstructure. Also, the inclusion of the ground POFA has reduced the charge passed of grout indicating its capacity as chloride resistance agent. © 2015 Elsevier Ltd.
Fisher I.,Watervale Systems Pty Ltd |
Kastl G.,Level Inc |
Sathasivan A.,Curtin University Australia
Water Research | Year: 2012
Maintaining a chlorine residual is a major disinfection goal in many water distribution systems. A suitable general model of chlorine decay in the transported bulk water is an essential component for efficiently modelling chlorine concentration in distribution systems. The two-reactant model meets basic suitability criteria, including accurate prediction of chlorine residual over hundreds of hours, commencing with chlorine concentration 0-4 mg/L. This model was augmented with an equation that increases the decay coefficients with temperature according to Arrhenius theory. The augmented model was calibrated against decay-test data sets to obtain a single invariant set of parameters for each water. Model estimates of chlorine residuals over time closely matched decay-test data, over the usual operating ranges of initial chlorine concentration (1-4 mg/L) and temperature (3.5-28 °C). When the augmented model was fitted to partial data sets, it also predicted the data reserved for validation very well, suggesting that this model can accurately predict the combined effect of initial chlorine concentration and temperature on chlorine bulk decay in distribution systems, using a single set of invariant parameters for a given source water. © 2012 Elsevier Ltd.
Mumby K.,Northumbria University |
Whitworth A.,Curtin University Australia
International Journal of Language and Communication Disorders | Year: 2012
Background: Despite recognition of the need for increased long-term support for people with aphasia following stroke, there remains limited evidence for effective service-level interventions. Aims: To evaluate the outcomes and experiences of people participating in the Communication Hub for Aphasia in North Tyneside (CHANT), a 2-year partnership project between health, local authority and third-sector services, shaped by people with aphasia, which provided a coordinated programme of support and interventions for people with long-term aphasia following stroke. Methods & Procedures: Quantitative and qualitative methods were used in the evaluation. Thirty-nine participants with aphasia were recruited to the 12-month study as they became part of CHANT, with 20 completing all measures at the end of the study. Participants had no other speech and language therapy during the study. Quantitative measures (before and after intervention) were used for quality of life, self-report outcomes and goal attainment. Three of the participants with aphasia and three further people involved in the service (carer, volunteer, public sector worker) each agreed to a series of five semi-structured interviews over a 9-month period. A total of 28 interviews were collected using neutral interviewers; these were transcribed and analysed by a team within NVivo8 software, based on interpretive principles from grounded theory. Thematic analysis of the narratives explored the experience of engaging with CHANT, and the barriers and facilitators affecting quality of life. Outcomes & Results: People with aphasia made significant gains in quality of life (in particular, in communication and psychosocial adjustment to stroke) and self-report measures of change. A total of 82% of real-life goals set as part of intervention were fully or partially achieved at follow-up. Five core themes emerged from the narratives: 'Quality of life', 'Barriers', 'Facilitators', 'Types of CHANT activity' and 'Effectiveness'. The intervention was evaluated through the theme of 'Effectiveness' in relation to the other themes, encapsulating emerging participant views (including the type and timeliness of activity, expectations of outcomes, resources and perceived value). The impact of the intervention was also analysed in terms of identifying barriers and providing facilitators. Conclusions & Implications: The quantitative and qualitative (narrative) findings were complementary in demonstrating the effectiveness of the CHANT service delivery model. Moreover, the narratives, through a longitudinal perspective, provided evidence about people's experience of intervention for long-term aphasia. The findings provide foundations for further work into long-term recovery, intervention and adjustment to aphasia post-stroke. © 2012 Royal College of Speech and Language Therapists.
Kazem A.,Tafresh University |
Sharifi E.,Tafresh University |
Hussain F.K.,University of Technology, Sydney |
Saberi M.,Islamic Azad University at Tafresh |
Hussain O.K.,Curtin University Australia
Applied Soft Computing Journal | Year: 2013
Due to the inherent non-linearity and non-stationary characteristics of financial stock market price time series, conventional modeling techniques such as the Box-Jenkins autoregressive integrated moving average (ARIMA) are not adequate for stock market price forecasting. In this paper, a forecasting model based on chaotic mapping, firefly algorithm, and support vector regression (SVR) is proposed to predict stock market price. The forecasting model has three stages. In the first stage, a delay coordinate embedding method is used to reconstruct unseen phase space dynamics. In the second stage, a chaotic firefly algorithm is employed to optimize SVR hyperparameters. Finally in the third stage, the optimized SVR is used to forecast stock market price. The significance of the proposed algorithm is 3-fold. First, it integrates both chaos theory and the firefly algorithm to optimize SVR hyperparameters, whereas previous studies employ a genetic algorithm (GA) to optimize these parameters. Second, it uses a delay coordinate embedding method to reconstruct phase space dynamics. Third, it has high prediction accuracy due to its implementation of structural risk minimization (SRM). To show the applicability and superiority of the proposed algorithm, we selected the three most challenging stock market time series data from NASDAQ historical quotes, namely Intel, National Bank shares and Microsoft daily closed (last) stock price, and applied the proposed algorithm to these data. Compared with genetic algorithm-based SVR (SVR-GA), chaotic genetic algorithm-based SVR (SVR-CGA), firefly-based SVR (SVR-FA), artificial neural networks (ANNs) and adaptive neuro-fuzzy inference systems (ANFIS), the proposed model performs best based on two error measures, namely mean squared error (MSE) and mean absolute percent error (MAPE). Copyright © 2012 Published by Elsevier B.V. All rights reserved.
Farrugia A.,Curtin University Australia
International Journal of Drug Policy | Year: 2014
Education programs are a central element of Australian harm reduction drug policy. Considered less judgmental and more effective than the punitive policies of Australia's past, harm reduction drug education is premised on the goal of reducing 'risks' and harms associated with illicit drug use rather than an elimination of use per se. In this article I analyse two sets of key texts designed to reduce drug related harm in Australia: harm reduction teaching resources designed for classroom use and social marketing campaigns that are targeted to a more general audience. I identify two significant accounts of young people's drug use present in Australian harm reduction drug education: 'damaged mental health' and 'distress'. I then draw on some of Deleuze and Guattari's key concepts to consider the harm reducing potential these accounts may have for young people's drug using experiences. To demonstrate the potential limitations of current drug education, I refer to an established body of work examining young people's experiences of chroming. From here, I argue that the accounts of 'damaged mental health' and 'distress' may work to limit the capacity of young drug users to practice safer drug use. In sum, current Australian harm reduction drug education and social marketing may be producing rather than reducing drug related harm. © 2014 Elsevier B.V.
Duff C.,Curtin University Australia
International Journal of Drug Policy | Year: 2014
'Context' is one of the most enduring analytical devices in social science accounts of alcohol and other drug (AOD) use, although its elaboration tends to emphasise macro-structural processes (like economic change, law enforcement, health policy, racism or stigma) at the expense of more finely-grained understandings of the place and time of consumption. Drawing on Gilles Deleuze's notion of the assemblage, and its reception in recent critical geographies of AOD use, I will characterise context as an assemblage of social, affective and material forces. Such a characterisation is not indifferent to the range of structural forces that are often understood to mediate AOD use. Rather, it is concerned to document how these forces actually participate in the modulations of consumption. The assemblage will thus be construed in ways that align context with the 'real conditions' (place and time) of drug use. I will develop this argument by way of a case study drawn from a recent qualitative study of the social contexts of methamphetamine use in Melbourne. My goal is to document the ways 'context' is produced in the activity of drug use, and how 'context' so constructed, comes to modulate this use. By contrasting traditional approaches to the analysis of context with methods borrowed from Deleuze, I aim to transcend structural understandings of context in order to clarify the active, local and contingent role of contexts in the mediation of what bodies do 'on' and 'with' drugs. © 2013 Elsevier B.V.
Haddow G.,Curtin University Australia
Library and Information Science Research | Year: 2013
A key component of Vincent Tinto's model of retention is the importance of student integration in the academic institution. Library use can be regarded as a form of integration within such institutions. A quantitative approach was applied to demonstrate how institutional data can be combined to examine library use and retention at a single institution. Undergraduate student and library use data were analyzed to identify results that suggested associations between library use and student retention. Library use was measured by log-ins to electronic resources, as well as borrowing from the library. The undergraduate students enrolled for the first time in 2010 comprised the population, Sub-group student characteristics, age and socioeconomic status, underwent further analysis. The findings show retained students log-in to authenticated resources and borrow from the library at higher rates than withdrawn students. Mature age students withdraw from the university at higher rates than younger students. Log-ins to authenticated resources increase as students progress over time through their university programs. No notable associations were found among socioeconomic background, library use, and retention. For the institution, these findings can inform the development of library services to target specific student groups on the basis that higher library use may lead to improved integration and retention. In addition, the study describes a research design that is replicable in other institutions and contributes to library use and retention literature. © 2013 Elsevier Inc.
Taylor C.K.,Curtin University Australia
Zootaxa | Year: 2011
A morphological phylogenetic analysis is conducted of Australasian harvestmen previously included in the family Monoscutidae. Monophyly of Monoscutidae is not supported, and the subfamilies Monoscutinae and Megalopsalidinae are synonymised with the South American subfamily Enantiobuninae. Monoscutidae is re-synonymised with the family Neopilionidae. The analysis also demonstrates the polyphyly of species previously assigned to the genus Megalopsalis. Megalopsalis epizephyros new species, M. eremiotis new species, M. leptekes new species and M. pilliga new species are described and M. serritarsus and M. hoggi are redescribed, all from Australia. Hypomegalopsalis tanisphyros new genus and species is described from Western Australia. Megalopsalis linnaei is transferred to Tercentenarium new genus. Forsteropsalis new genus is established to include species from New Zealand (including Auckland Island): Macropsalis chiltoni (type species), Pantopsalis distincta, Macropsalis fabulosa, Pantopsalis grayi, Megalopsalis grimmetti, Megalopsalis inconstans, Megalopsalis marplesi, Megalopsalis nigra and Pantopsalis wattsi. © 2011 Magnolia Press.
Shahin M.A.,Curtin University Australia
Soils and Foundations | Year: 2014
The design of pile foundations requires good estimations of the pile load-carrying capacity and the settlement. Designs for bearing capacity and settlement have been traditionally carried out separately. However, soil resistance and settlement are influenced by each other, and thus, the design of pile foundations should consider the bearing capacity and the settlement together. This requires that the full load-settlement response of the piles be accurately predicted. However, it is well known that the actual load-settlement response of pile foundations can only be obtained through load tests carried out in-situ, which are expensive and time-consuming. In this technical note, recurrent neural networks (RNNs) were used to develop a prediction model that can resemble the load-settlement response of steel driven piles subjected to axial loading. The developed RNN model was calibrated and validated using several in-situ full-scale pile load tests, as well as cone penetration test (CPT) data. The results indicate that the developed RNN model has the ability to reliably predict the load-settlement response of axially loaded steel driven piles, and thus, can be used by geotechnical engineers for routine design practice. © 2014 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved.
Islam M.N.,Curtin University Australia
Machining Science and Technology | Year: 2013
This article reports the experimental and analytical results of an investigation of additional factors that affect the dimensional accuracy and surface finish of turned parts besides the three major cutting parameters - cutting speed, feed rate, and depth of cut. The selected additional factors were cooling method, blank size, and work material. A three-level, three-parameter experiment was planned using design-of-experiment methodology. The three levels of independent input parameters were: for cooling method - dry turning, flood turning, and minimum quantity lubrication turning; for blank size - φ20, 40, and 60 mm; and for work material - aluminium 6061, mild steel 1030, and alloy steel 4340. The measured output parameters were the two most widely used dimensional accuracy characteristics of turned parts - diameter error and circularity - and the surface finish characteristic arithmetic average. The results were analyzed applying three methods: traditional analysis, Pareto ANOVA, and Taguchi method. The results reveal that, while work material has the greatest effect on diameter error and surface roughness, the major contributor to circularity is blank size. © 2013 Copyright Taylor and Francis Group, LLC.
Rong Y.,Curtin University Australia
IEEE Wireless Communications Letters | Year: 2012
We consider a practical dual-hop nonregenerative multiple-input multiple-output (MIMO) relay system, where the relay node only knows the correlation matrix of the relay-destination channel. A nonlinear minimal mean-squared error (MMSE)-based decision feedback equalizer (DFE) is used at the destination node to retrieve the source signals. We derive the structure of statistically optimal source and relay precoding matrices to minimize a class of objective functions which are multiplicatively Schur-convex with respect to the diagonal elements of the MSE matrix. Simulation results demonstrate that the proposed algorithm has a very close performance compared to MIMO relay system with full channel knowledge at the relay node, and thus is very useful for practical relay systems. © 2012 IEEE.
Zhang X.,University of Western Australia |
Hao H.,Curtin University Australia |
Wang Z.,Beijing Institute of Technology
Engineering Structures | Year: 2014
A series of field blasting tests of glass windows to blast loadings have been recently conducted. This is the second paper to report the testing data on monolithic tempered glass windows. While the first paper reports the glass panel response and failure modes, the current paper concentrates on the glass fragments induced by the blast loadings. Thermally tempered glass has been often adopted for monolithic windows to reduce ejecting fragment hazards after window fracture. However, previous blast tests conducted on monolithic tempered glass reported that in addition to small cubic fragments the shattered glass panes could break into large and jagged fragments similar to the cases in annealed glass which poses much more debris threats than expected. A thorough study on tempered glass fragments produced by air blast pressure is therefore necessary for better protection of human safety. In this paper, fragment characteristics of monolithic tempered glass windows observed in blasting tests are analyzed and presented. 1.5. m × 1.2. m monolithic panes of two commonly used thicknesses, i.e. 6. mm and 10. mm, fully clamped onto the opening of an enclosed RC frame were tested with 5-10. kg TNT charge detonated at 4.5-12.3. m stand-off distances. Glass fragment mass and splash distributions both in front of and behind the windows were evaluated with respect to reflected pressure and glass specification. Fragment size and shape were also analyzed. High-speed cameras were used to monitor glass window fracture processes. Fragment velocities were determined by post-processing the high-speed camera images. Fragment ejecting velocities were evaluated with respect to the reflected impulse. Negative pressure was found to significantly influence the fragment ejecting velocity and fragment splash distributions. © 2014 Elsevier Ltd.
Human B.A,Western Australian Fisheries and Marine Research Laboratories |
Davies A.,Curtin University Australia
Marine Policy | Year: 2010
Stakeholder consultation is being adopted as standard practice in the planning and management of natural resource management programs. While the utility of stakeholder participation has been investigated for the evaluation and implementation phases of natural resource management programs, few studies have examined the utility of stakeholder consultation during the initial phases of developing such programs. This paper presents a case study from a project developing a marine and coastal monitoring program for the Pilbara and Kimberley region of northern Western Australia. Via a series of workshops held in the region, stakeholders were asked to prioritise future research needs using several voting procedures. During the analyses of the results from the different voting procedures, it became apparent that there were high levels of inconsistency, poor correlation, and contradiction, between participants' responses. Despite the rigour of the selection process used to identify 'suitable' stakeholders for the workshops, these results show that stakeholders did not have the technical or broader contextual knowledge about marine ecosystems to effectively and objectively contribute to the research prioritisation and planning process. Based on the outcomes of this study, we argue that project designers need to be clear about why they are involving stakeholders in a project, particularly in light of the costs involved (financial, time, resources, costs to the stakeholder) in stakeholder consultation. Stakeholder involvement may be appropriate in later stages of developing natural resource management programs (implementation and management), however, stakeholder involvement is not appropriate in the initial phases of such programs, where scientific expertise is essential in formulating scientific concepts and frameworks. Crown Copyright © 2009.
Gibson S.,Solaris Care Center |
McConigley R.,Curtin University Australia
Supportive Care in Cancer | Year: 2016
Aim: The aim of this study was to identify the incidence, causes, risk factors and interventions for cancer patients requiring unplanned admissions within 14 days of discharge at a large metropolitan private hospital without a co-located emergency department. Methods: Retrospective data were collected on cancer patients who had an unplanned admission within 14 days of discharge during the period December 1, 2011 and May 31, 2012. Data were collected from the inpatient bed administration database and medical record review. Variables collected included demographics, cancer diagnosis, reasons for admission, interventions, and length of stay. Results: A total of 133 oncology patients required 206 unplanned admissions (UPAs). The most common cancer diagnoses associated with unplanned readmission were upper gastrointestinal (25.4 %), colorectal (19.6 %), gynaecological (18.8 %) and breast (13.8 %) cancers. The symptoms most commonly associated with unplanned re-admission were pain (16 %); infection not associated with neutropaenia (15.5 %); fever and febrile neutropaenia (14.6 %); nausea, vomiting and dehydration (13.6 %); dyspnoea (8.3 %) and altered neurological status (7.8 %). The median length of stay (LOS) was 6 days. Length of stay during UPA was decreased for patients with a partner and for those who had a palliative care consult. The need for psychological supports was related to a longer LOS during UPA. Conclusion: Cancer patients are at a significant risk of requiring unscheduled care and admission. Strategies and services to limit the burden on patients and the health care system should be reviewed to minimise the incidence of unplanned admission. © 2015, Springer-Verlag Berlin Heidelberg.
Suenaga H.,Curtin University Australia
Mathematics and Computers in Simulation | Year: 2013
This study examines bias in a term-structure model of commodity prices in specifying the true stochastic dynamics of underlying spot price. The bias is quantified by comparing the model estimated by the conventional method of estimating all model parameters simultaneously with a panel of futures prices and the model estimated by an alternative method of estimating model parameters in two steps. In this alternative approach, a subset of model parameters is first estimated on the first difference of observed futures prices so that these parameters are free from bias in specifying deterministic price variation and the dynamics of the underlying state variables. In the second step, the remaining model parameters are estimated on the futures price equations, while holding the parameters estimated in the first step. Empirical applications to four commodities (gold, crude oil, natural gas, and corn) reveal that the two-factor model widely considered in the literature is subject to a misspecification bias of substantial size. Out-of-sample forecast test indicates that, for three of the four commodities considered, the model estimated by the sequential method yields a considerably more accurate price forecast than the model estimated by the simultaneous method. © 2013 IMACS.
Nemchin A.A.,Curtin University Australia |
Horstwood M.S.A.,British Geological Survey |
Whitehouse M.J.,Swedish Museum of Natural History
Elements | Year: 2013
High-spatial-resolution isotope analyses have revolutionised U-(Th-)Pb geochronology. These analyses can be done at scales of a few tens of microns or less using secondary ion mass spectrometry or laser ablation inductively coupled plasma mass spectrometry. They allow determination of the internal age variation of uranium- and thorium-bearing minerals and as a consequence much greater understanding of Earth system processes. The determination of variation on the micron scale necessitates the sampling of small volumes, which restricts the achievable precision but allows discrimination of discrete change, linkage to textural information, and determination of multiple isotopic and elemental data sets on effectively the same material. High-spatial-resolution analysis is being used in an increasing number of applications. Some of these applications have become fundamental to their scientific fields, while others have opened new opportunities for research.
Gao S.,Northwestern Polytechnical University |
Zhong Y.,Curtin University Australia |
Shirinzadeh B.,Monash University
Information Sciences | Year: 2010
This paper adopts the concept of random weighting estimation to multi-sensor data fusion. It presents a new random weighting estimation methodology for optimal fusion of multi-dimensional position data. A multi-sensor observation model is constructed for multi-dimensional position. Based on this observation model, a random weighting estimation algorithm is developed for estimation of position data from single sensors. Using the random weighting estimations from each single sensor, an optimization theory is established for optimal fusion of multi-sensor position data. Experimental results demonstrate that the proposed methodology can effectively fuse multi-sensor dimensional position data, and the fusion accuracy is much higher than that of the Kalman fusion method. © 2010 Elsevier Inc. All rights reserved.
Arshad M.,BC Hydro |
Islam S.M.,Curtin University Australia
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2011
Power transformers are designed to withstand system abnormalities such as over voltages and external short-circuits. Transformer monitoring and diagnostics are the effective techniques in preventing the eventual failures and contribute to ensure the plant's reliability. Transformer life mainly depends on the integrity of its solid insulation (cellulose). The solid insulation in transformers degrades with time at rates which depend on the temperature and the amount of moisture, oxygen and acids in the insulation system. Moisture and oxygen cause the paper insulation to decay much faster than normal. Moisture in a transformer accelerates the aging process and causes severe deterioration in the mechanical and electrical properties of insulation system. The aging of paper insulation is irreversible. The degree of polymerization value is a main relation between insulation deterioration and formation of aging products. To predict a failure or an unusual behavior, an accurate interpretation of monitoring, diagnostics and maintenance data is required. The monitoring of insulation system and verification of core and winding mechanical integrity allow optimization of the lifecycle management of an asset. This paper presents an investigation and condition assessment of 152 MVA, 512 kV, 1-phase, 2-winding generator step-up transformer having a history of combustible gases. © 2006 IEEE.
Jenkins H.D.B.,University of Warwick |
Glasser L.,Curtin University Australia
Journal of Chemical and Engineering Data | Year: 2010
Thermodynamic data are required for an understanding of the behavior of materials but are often lacking (or even unreliable) for a variety of reasons such as synthetic problems, purity issues, failure to correctly identify hydrolysis products, instability of the material, etc. Thus, it is necessary to develop procedures for the estimation of that data. The Thermodynamic Difference Rules (TDR) are additive approximations by which the properties of materials are estimated by reference to those of related materials. These rules appear in the form of the reliable Hydrate Difference Rule (HDR), based on the well-established properties of the large number of known hydrates, and the somewhat less certain Solvate Difference Rule (SDR). These rules are briefly surveyed and their application carefully delineated by a scheme and demonstrated by a number of calculated examples. © 2010 American Chemical Society.
Hay R.,Curtin University Australia
Sustainable Development | Year: 2010
Identity is formed gradually as we mature through personal development within societal (and natural) context. As such, it is group informed but individually directed and is strongly influenced by our family, community, place and natural surroundings. Together, these interwoven aspects of our lives help us each to create an identity that is unique and that should be able to be sustained over time. However, because we live within collectives and places that have often become less sustainable of late, this has a corresponding effect on our identity. The interactive relationship between identity and sustainability is therefore integral to how we understand and then address issues that currently confront us all. To investigate this relationship, three aspects of identity are considered together: the significance of an ecocentric philosophy, personal development oriented to service and transformational leadership. Interweaving these related reflections goes beyond a more limited view of identity, providing new directions for sustainability. © 2010 John Wiley & Sons, Ltd and ERP Environment.
Sun Z.,Curtin University Australia
The Scientific World Journal | Year: 2014
Invasive angiography has been widely accepted as the gold standard to diagnose cardiovascular pathologies. Despite its superior resolution of demonstrating atherosclerotic plaque in terms of degree of lumen stenosis, the morphological assessment for the plaque is insufficient for the analysis of plaque components, and therefore, unable to predict the risk status or vulnerability of atherosclerotic plaque. There is an increased body of evidence to show that the vasa vasorum play an important role in the initiation, progression, and complications of atherosclerotic plaque leading to major adverse cardiac events. This paper provides an overview of the evidence-based reviews of various imaging modalities with regard to their potential value for comprehensive characterization of the composition, burden, and neovascularization of atherosclerotic plaque. © 2014 Zhonghua Sun.
Williams C.J.,Curtin University Australia |
Williams C.J.,Curtin Health Innovation Research Institute |
McLeod S.,Charles Sturt University
International Journal of Speech-Language Pathology | Year: 2012
Within predominantly English-speaking countries such as the US, UK, Canada, New Zealand, and Australia, there are a significant number of people who speak languages other than English. This study aimed to examine Australian speech-language pathologists' (SLPs) perspectives and experiences of multilingualism, including their assessment and intervention practices, and service delivery methods when working with children who speak languages other than English. A questionnaire was completed by 128 SLPs who attended an SLP seminar about cultural and linguistic diversity. Approximately one half of the SLPs (48.4%) reported that they had at least minimal competence in a language(s) other than English; but only 12 (9.4%) reported that they were proficient in another language. The SLPs spoke a total of 28 languages other than English, the most common being French, Italian, German, Spanish, Mandarin, and Auslan (Australian sign language). Participants reported that they had, in the past 12 months, worked with a mean of 59.2 (range 1-100) children from multilingual backgrounds. These children were reported to speak between two and five languages each; the most common being: Vietnamese, Arabic, Cantonese, Mandarin, Australian Indigenous languages, Tagalog, Greek, and other Chinese languages. There was limited overlap between the languages spoken by the SLPs and the children on the SLPs' caseloads. Many of the SLPs assessed children's speech (50.5%) and/or language (34.2%) without assistance from others (including interpreters). English was the primary language used during assessments and intervention. The majority of SLPs always used informal speech (76.7%) and language (78.2%) assessments and, if standardized tests were used, typically they were in English. The SLPs sought additional information about the children's languages and cultural backgrounds, but indicated that they had limited resources to discriminate between speech and language difference vs disorder. © 2012 The Speech Pathology Association of Australia Limited.
Swartz D.A.,NASA |
Soria R.,Curtin University Australia |
Tennant A.F.,NASA |
Yukita M.,University of Alabama
Astrophysical Journal | Year: 2011
One hundred seven ultraluminous X-ray sources (ULXs) with 0.3-10.0keV luminosities in excess of 1039ergs-1 are identified in a complete sample of 127 nearby galaxies. The sample includes all galaxies within 14.5Mpc above the completeness limits of both the Uppsala Galaxy Catalogue and the Infrared Astronomical Satellite survey. The galaxy sample spans all Hubble types, a four-decade range in mass, 7.5 < log (M/M·) < 11.4, and in star formation rate, 0.0002 < SFR(M· yr -1) ≤ 3.6. ULXs are detected in this sample at rates of one per 3.2 × 1010 M·, one per 0.5 M ·yr-1 star formation rate, and one per 57Mpc 3 corresponding to a luminosity density of 2 × 10 37ergs-1Mpc-3. At these rates we estimate as many as 19 additional ULXs remain undetected in fainter dwarf galaxies within the survey volume. An estimated 14 objects, or 13%, of the 107 ULX candidates are expected to be background sources. The differential ULX luminosity function shows a power-law slope α -0.8 to -2.0 with an exponential cutoff at 20 × 1039ergs-1 with precise values depending on the model and on whether the ULX luminosities are estimated from their observed numbers of counts or, for a subset of candidates, from their spectral shapes. Extrapolating the observed luminosity function predicts at most one very luminous ULX, LX 1041ergs-1, within a distance as small as 100Mpc. The luminosity distribution of ULXs within the local universe cannot account for the recent claims of luminosities in excess of 2 × 1041ergs-1, requiring a new population class to explain these extreme objects. © 2011 The American Astronomical Society. All rights reserved.
Wittwer J.E.,La Trobe University |
Webster K.E.,La Trobe University |
Hill K.,Curtin University Australia
Archives of Physical Medicine and Rehabilitation | Year: 2013
Objective: To determine whether rhythmic music and metronome cues alter spatiotemporal gait measures and gait variability in people with Alzheimer disease (AD). Design: A repeated-measures study requiring participants to walk under different cueing conditions. Setting: University movement laboratory. Participants: Of the people (N=46) who met study criteria (a diagnosis of probable AD and ability to walk 100m) at routine medical review, 30 (16 men; mean age ± SD, 80±6y; revised Addenbrooke's Cognitive Examination range, 26-79) volunteered to participate. Interventions: Participants walked 4 times over an electronic walkway synchronizing to (1) rhythmic music and (2) a metronome set at individual mean baseline comfortable speed cadence. Main Outcome Measures: Gait spatiotemporal measures and gait variability (coefficient of variation [CV]). Data from individual walks under each condition were combined. A 1-way repeated-measures analysis of variance was used to compare uncued baseline, cued, and retest measures. Results: Gait velocity decreased with both music and metronome cues compared with baseline (baseline, 110.5cm/s; music, 103.4cm/s; metronome, 105.4cm/s), primarily because of significant decreases in stride length (baseline, 120.9cm; music, 112.5cm; metronome, 114.8cm) with both cue types. This was coupled with increased stride length variability compared with baseline (baseline CV, 3.4%; music CV, 4.3%; metronome CV, 4.5%) with both cue types. These changes did not persist at (uncued) retest. Temporal variability was unchanged. Conclusions: Rhythmic auditory cueing at comfortable speed tempo produced deleterious effects on gait in a single session in this group with AD. The deterioration in spatial gait parameters may result from impaired executive function associated with AD. Further research should investigate whether these instantaneous cue effects are altered with more practice or with learning methods tailored to people with cognitive impairment. © 2013 by the American Congress of Rehabilitation Medicine.
Phillips J.L.,The University of Notre Dame Australia |
Halcomb E.J.,University of Western Sydney |
Davidson P.M.,Curtin University Australia
Journal of Pain and Symptom Management | Year: 2011
Context: Over the past decade, there has been widespread adoption of end-of-life care pathways as a tool to better manage care of the dying in a variety of care settings. The adoption of various end-of-life care pathways has occurred despite lack of robust evidence for their use. Objectives: This integrative review identified published studies evaluating the impact of an end-of-life care pathway in the acute and hospice care setting from January 1996 to April 2010. Methods: A search of the electronic databases Scopus and Cumulative Index of Nursing and Allied Health Literature as well as Medline and the World Wide Web were undertaken. This search used Medical Subject Headings key words including "end-of-life care," "dying," "palliative care," "pathways," "acute care," and "evaluation." Articles were reviewed by two authors using a critical appraisal tool. Results: The search revealed 638 articles. Of these, 26 articles met the inclusion criteria for this integrative review. No randomized controlled trials were reported. The majority of these articles reported baseline and post implementation pathway chart audit data, whereas a smaller number were local, national, or international benchmarking studies. Most of the studies emerged from the United Kingdom, with a smaller number from the United States, The Netherlands, and Australia. Conclusion: Existing data demonstrate the utility of the end-of-life pathway in improving care of the dying. The absence of randomized controlled trial data, however, precludes definitive recommendations and underscores the importance of ongoing research. © 2011 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.
Paul V.,University of Santiago de Compostela |
McKenzie F.H.,Curtin University Australia
Land Use Policy | Year: 2013
There has been a growing literature on alternative food networks (AFNs); structures that reconfigure the systems of production, distribution and consumption of food. Part of this literature emphasises the local scale and the idea of proximity. In a world that is increasingly urban, AFNs at a local scale can be more easily developed by linking peri-urban farmlands and cities. However, agriculture in the rural-urban fringe struggles to survive in the face of urban pressures and sprawl; a process which undermines viable agricultural production in the city's countryside. A widely used strategy to address these pressures has been farmland protection, undertaken in different ways depending on the legal framework of particular countries. This paper considers farmland conservation and AFNs development issues through a case-study of the Baix Llobregat Agricultural Park (BLAP) in metropolitan Barcelona. It concludes that AFNs in peri-urban areas are only possible if farmland preservation is guaranteed, and that the former does not come as a direct consequence of the latter. The specific conditions in which both can occur will be of interest for scholars as well as policy-makers and planners. © 2012 Elsevier Ltd.
Cooper C.E.,Curtin University Australia |
Withers P.C.,University of Western Australia
Physiological and Biochemical Zoology | Year: 2010
Strict criteria have been established for measurement of basal metabolic rate and standard evaporative water loss to ensure that data can be compared intra- and interspecifically.However, data-sampling regimes vary, from essentially continuous sampling to interrupted (switching) systems with data recorded periodically at more widely spaced intervals. Here we compare one continuous and three interrupted sampling regimes to determine whether sampling regime has a significant effect on estimation of basal metabolic rate or standard evaporativewater loss. Compared to continuous 20-s sampling averaged over 20 min, sampling every 6 min and averaging over 60 min overestimated basal metabolic rate and evaporative water loss, sampling every 3 min and averaging over 21 min underestimated basal metabolic rate, and sampling every 12 min and averaging over 36 min showed no difference in estimates. Increasing the period over which the minimum mean was calculated significantly increased estimates of physiological variables. Reducing the frequency of sampling from 20 s to a longer interval of 3, 6, or 12 min underestimated basal metabolic rate but not evaporative water loss. This indicates that sampling frequency per se influences estimates of basal metabolic rate and that differences are not just an artifact of differences in the period over which the mean is calculated. Sampling regime can have a highly significant influence on estimation of standard physiological variables, although the actual differences between sampling regimes were generally small (usually <5%). Although continuous sampling is the preferred sampling regime for openflowrespirometry studies, if time and cost are prohibitive, then use of an appropriate switching system will result in smaller errors than measuring individuals continuously for shorter periods. © 2010 by The University of Chicago. All rights reserved.
Souders A.K.,Memorial University of Newfoundland |
Sylvester P.J.,Memorial University of Newfoundland |
Myers J.S.,Curtin University Australia
Contributions to Mineralogy and Petrology | Year: 2013
Isotopic analyses of ancient mantle-derived magmatic rocks are used to trace the geochemical evolution of the Earth's mantle, but it is often difficult to determine their primary, initial isotope ratios due to the detrimental effects of metamorphism and secondary alteration. We present in situ analyses by LA-MC-ICPMS for the Pb isotopic compositions of igneous plagioclase (An75-89) megacrysts and the Hf isotopic compositions of BSE-imaged domains of zircon grains from two mantle-derived anorthosite complexes from south West Greenland, Fiskenæsset and Nunataarsuk, which represent two of the best-preserved Archean anorthosites in the world. In situ LA-ICPMS U-Pb geochronology of the zircon grains suggests that the minimum crystallization age of the Fiskenæsset complex is 2,936 ± 13 Ma (2σ, MSWD = 1. 5) and the Nunataarsuk complex is 2,914 ± 6. 9 Ma (2σ, MSWD = 2. 0). Initial Hf isotopic compositions of zircon grains from both anorthosite complexes fall between depleted mantle and a less radiogenic crustal source with a total range up to 5 εHf units. In terms of Pb isotopic compositions of plagioclase, both anorthosite complexes share a depleted mantle end member yet their Pb isotopic compositions diverge in opposite directions from this point: Fiskenæsset toward a high-μ, more radiogenic Pb, crustal composition and Nunataarsuk toward low-μ, less radiogenic Pb, crustal composition. By using Hf isotopes in zircon in conjunction with Pb isotopes in plagioclase, we are able to constrain both the timing of mantle extraction of the crustal end member and its composition. At Fiskenæsset, the depleted mantle melt interacted with an Eoarchean (~3,700 Ma) mafic crust with a maximum 176Lu/177Hf ~0. 028. At Nunataarsuk, the depleted mantle melt interacted with a Hadean (~4,200 Ma) mafic crust with a maximum 176Lu/177Hf ~0. 0315. Evidence from both anorthosite complexes provides support for the long-term survival of ancient mafic crusts that, although unidentified at the surface to date, could still be present within the Fiskenæsset and Nunataarsuk regions. © 2012 Springer-Verlag.
Dhami N.K.,Thapar University |
Sudhakara Reddy M.,Thapar University |
Mukherjee A.,Curtin University Australia
Frontiers in Microbiology | Year: 2014
Since ages, architects and artists worldwide have focused on usage of durable stones as marble and limestone for construction of beautiful and magnificent historic monuments as European Cathedrals, Roman, and Greek temples, Taj Mahal etc. But survival of these irreplaceable cultural and historical assets is in question these days due to their degradation and deterioration caused by number of biotic and abiotic factors. These causative agents have affected not only the esthetic appearance of these structures, but also lead to deterioration of their strength and durability. The present review emphasizes about different causative agents leading to deterioration and application of microbially induced calcium carbonate precipitation as a novel and potential technology for dealing with these problems. The study also sheds light on benefits of microbial carbonate binders over the traditional agents and future directions. © 2014 Dhami, Reddy and Mukherjee.
McManus A.,Curtin University Australia
Australasian Medical Journal | Year: 2013
Previously, the main focus of primary health care practices was to diagnose and treat patients. The identification of risk factors for disease and the prevention of chronic conditions have become a part of everyday practice. This paper provides an argument for training primary health care (PHC) practitioners in health promotion, while encouraging them to embrace innovation within their practice to streamline the treatment process and improve patient outcomes. Electronic modes of communication, education and training are now commonplace in many medical practices. The PHC sector has a small window of opportunity in which to become leaders within the current model of continuity of care by establishing their role as innovators in the prevention, treatment and management of disease. Not only will this make their own jobs easier, it has the potential to significantly impact patient outcomes.
Jiwa M.,Curtin University Australia
Australasian Medical Journal | Year: 2013
The development of innovations for clinical practice warrants active engagement of clinicians in the research process. This requires attention to factors that serve as incentive to participate. The explanation for the success of factors that encourage practitioners to participate in research can be found in sources of satisfaction and dissatisfaction with clinical practice. It is also important to consider intrinsic incentives such as common and troublesome clinical presentations that are related to workload or unsatisfactory clinical encounters. This review will consider each of these factors and suggest ways in which clinicians, especially general practitioners, may be invited to assist on research projects.
Lannes A.,University Paris - Sud |
Teunissen P.J.G.,Technical University of Delft |
Teunissen P.J.G.,Curtin University Australia
Journal of Geodesy | Year: 2011
The first objective of this paper is to show that some basic concepts used in global navigation satellite systems (GNSS) are similar to those introduced in Fourier synthesis for handling some phase calibration problems. In experimental astronomy, the latter are at the heart of what is called 'phase closure imaging.' In both cases, the analysis of the related structures appeals to the algebraic graph theory and the algebraic number theory. For example, the estimable functions of carrier-phase ambiguities, which were introduced in GNSS to correct some rank defects of the undifferenced equations, prove to be 'closure-phase ambiguities:' the so-called 'closure-delay' (CD) ambiguities. The notion of closure delay thus generalizes that of double difference (DD). The other estimable functional variables involved in the phase and code undifferenced equations are the receiver and satellite pseudo-clock biases. A related application, which corresponds to the second objective of this paper, concerns the definition of the clock information to be broadcasted to the network users for their precise point positioning (PPP). It is shown that this positioning can be achieved by simply having access to the satellite pseudo-clock biases. For simplicity, the study is restricted to relatively small networks. Concerning the phase for example, these biases then include five components: a frequency-dependent satellite-clock error, a tropospheric satellite delay, an ionospheric satellite delay, an initial satellite phase, and an integer satellite ambiguity. The form of the PPP equations to be solved by the network user is then similar to that of the traditional PPP equations. As soon as the CD ambiguities are fixed and validated, an operation which can be performed in real time via appropriate decorrelation techniques, estimates of these float biases can be immediately obtained. No other ambiguity is to be fixed. The satellite pseudo-clock biases can thus be obtained in real time. This is not the case for the satellite-clock biases. The third objective of this paper is to make the link between the CD approach and the GNSS methods based on the notion of double difference. In particular, it is shown that the information provided by a maximum set of independent DDs may not reach that of a complete set of CDs. The corresponding defect is analyzed. One of the main results of the corresponding analysis concerns the DD-CD relationship. In particular, it is shown that the DD ambiguities, once they have been fixed and validated, can be used as input data in the 'undifferenced CD equations.' The corresponding algebraic operations are described. The satellite pseudo-clock biases can therefore be also obtained via particular methods in which the notion of double differencing is involved. © 2011 The Author(s).
Yamasaki K.,Sojo University |
Chuang V.T.G.,Curtin University Australia |
Maruyama T.,Kumamoto University |
Otagiri M.,Sojo University
Biochimica et Biophysica Acta - General Subjects | Year: 2013
Background Human serum albumin acts as a reservoir and transport protein for endogenous (e.g. fatty acids or bilirubin) and exogenous compounds (e.g. drugs or nutrients) in the blood. The binding of a drug to albumin is a major determinant of its pharmacokinetic and pharmacodynamic profile. Scope of review The present review discusses recent findings regarding the nature of drug binding sites, drug-albumin binding in certain diseased states or in the presence of coadministered drugs, and the potential of utilizing albumin-drug interactions in clinical applications. Major conclusions Drug-albumin interactions appear to predominantly occur at one or two specific binding sites. The nature of these drug binding sites has been fundamentally investigated as to location, size, charge, hydrophobicity or changes that can occur under conditions such as the content of the endogenous substances in question. Such findings can be useful tools for the analysis of drug-drug interactions or protein binding in diseased states. A change in protein binding is not always a problem in terms of drug therapy, but it can be used to enhance the efficacy of therapeutic agents or to enhance the accumulation of radiopharmaceuticals to targets for diagnostic purposes. Furthermore, several extracorporeal dialysis procedures using albumin-containing dialysates have proven to be an effective tool for removing endogenous toxins or overdosed drugs from patients. General significance Recent findings related to albumin-drug interactions as described in this review are useful for providing safer and efficient therapies and diagnoses in clinical settings. This article is part of a Special Issue entitled Serum Albumin. © 2013 Elsevier B.V.
Saptoro A.,Curtin University Australia
Theoretical Foundations of Chemical Engineering | Year: 2012
Recently, artificial neural networks, especially feedforward neural networks, have been widely used for the identification and control of nonlinear dynamical systems. However, the determination of a suit- able set of structural and learning parameter value of the feedforward neural networks still remains a difficult task. This paper is concerned with the use of extended Kalman filter and unscented Kalman filter based feed- forward neural networks training algorithms. The comparisons of the performances of both algorithms are discussed and illustrated using a simulated example. The simulation results show that in terms of mean squared errors, unscented Kalman filter algorithm is superior to the extended Kalman filter and back-prop- agation algorithms since there are improvements between 2.45-21.48% (for training) and 8.35-29.15% (for testing). This indicates that unscented Kalman filter based feedforward neural networks learning could be a good alternative in artificial neural network models based applications for nonlinear dynamical systems. © Pleiades Publishing, Ltd., 2012.
Huang X.-L.,CAS Guangzhou Institute of Geochemistry |
Wilde S.A.,Curtin University Australia |
Zhong J.-W.,CAS Guangzhou Institute of Geochemistry |
Zhong J.-W.,Kunming University of Science and Technology
Precambrian Research | Year: 2013
The Dengfeng and Taihua Complexes are well-exposed Neoarchean to Paleoproterozoic units in the southern segment of the Trans-North China Orogen (TNCO). Zircon U-Pb dating shows that the Dengfeng Complex records two episodes (2568±11Ma and 2306±6Ma) of tonalite-trondhjemite-granodiorite (TTG) magmatism. All of the TTG rocks are characterized by high SiO2 (66.7-75.4wt%), Na2O (3.20-5.06wt%) and relatively low MgO (0.40-1.78wt%). The Late Neoarchean TTG gneisses have very low contents of HREE (YbN=0.69-2.75) and Y (1.73-7.07ppm), with moderate [La/Yb]N (24.1-53.8) and high Sr/Y (65.1-291.3) ratios. The Early Paleoproterozoic TTG gneisses have low contents of HREE (YbN=2.93-6.37) and Y (6.7-11.0ppm), with moderate [La/Yb]N (10.1-27.0) and Sr/Y (10.6-52.1) ratios. Both suites show pronounced negative Nb-Ta, P and Ti anomalies but positive Sr and Pb anomalies. The Late Neoarchean TTG gneisses all have similar bulk-rock Nd and zircon Hf model ages with mainly positive eNd(t), and are interpreted as resulting from the melting of dominantly juvenile thickened lower crust with residual garnet and amphibole. The Early Paleoproterozoic TTG gneisses have extremely variable eNd(t) (-6.23 to +4.23) and heterogeneous zircon eHf(t) (-3.3 to +3.1), which are also best interpreted as resulting from the partial melting of thickened lower crust with residual amphibole and garnet. The Taihua Complex in the Xiaoqinling area records three episodes of Early Paleoproterozoic TTG magmatism (2.48Ga at Caotan, 2.31Ga at Houjiacun and 2.16Ga at Bayuan), younger than the Taihua Complex in the Lushan area (2.85-2.72Ga). All rocks have relatively low contents of HREE (YbN=1.03-8.32) and Y (2.84-24ppm), with moderate [La/Yb]N (8.7-88.4) and Sr/Y (19.8-125.8) ratios, and show negative Ta-Nb and Ti anomalies and positive Sr and Pb anomalies. The Caotan gneisses at 2.48Ga and the Houjiacun TTG gneisses at 2.31Ga have low Mg# (0.14-0.45), low Cr (<42ppm) and Ni contents (1-21ppm), with variable but overall positive eNd(t) and eHf(t) values, and were derived from the partial melting of thickened lower crust with residual garnet and amphibole. The younger Bayuan TTG gneisses at 2.16Ga have low SiO2 (57.11-64.89wt%), high MgO (2.64-4.62wt%), Cr (100-247ppm) and Ni (32-80ppm), with negative whole rock eNd(t) and zircon eHf(t) values, resulted from the partial melting of delaminated lower crust that interacted with peridotitic mantle.The geochronology of the Dengfeng Complex (in the Dengfeng area) and the Taihua Complex (in the Lushan, Xiong'er and Xiaoqinling areas) reveals at least four magmatic episodes in the southern segment of the TNCO from the Late Mesoarchean to Early Paleoproterozoic (2.85-2.72Ga, 2.57-2.48Ga, 2.34-2.30Ga and 2.20-2.07Ga). The rocks of the two early episodes are dominantly of juvenile compositions with mostly positive whole rock eNd(t) and zircon eHf(t) values, suggesting two episodes of crustal growth formed in a subduction tectonic setting. The magmatic rocks of the third episode consist of both the juvenile and pre-existing crustal materials with variable whole rock eNd(t) and zircon eHf(t) values, which were generated in a subduction zone during the initial assembly of the NCC within the Columbia supercontinent cycle. The final episode of magmatism lacks juvenile materials with whole rock eNd(t) and zircon eHf(t) values being consistently negative. These may have resulted from the orogenic collapse. The episodic continental growth recorded in the southern segment of the TNCO was caused by subduction and consequent orogeny, consistent with global supercontinent cycles within the Late Archean and Early Paleoproterozoic. © 2013 Elsevier B.V.
Blyth A.J.,Curtin University Australia |
Shutova Y.,University of New South Wales |
Smith C.,La Trobe University
Organic Geochemistry | Year: 2013
The determination of δ13C values in speleothems is of considerable importance in palaeoenvironmental research, but has focussed solely on analysis of the carbonate. Here we demonstrate a new method for analysing the δ13C values of organic matter (OM) trapped in speleothems, utilising flow injection liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). Developmental analysis using a homogenised speleothem powder showed that the method is robust, with repeated digests and analyses having an average standard deviation of 0.1‰. Dilution tests with samples of 4-23μg total organic carbon (TOC) show relatively small linearity effects, with the overall standard deviation across a peak response range of 1700-9000mV being 0.2‰. © 2012 Elsevier Ltd.
Venkatesh V.,University of Arkansas |
Chan F.K.Y.,Curtin University Australia |
Thong J.Y.L.,Hong Kong University of Science and Technology
Journal of Operations Management | Year: 2012
Advances in Internet technologies have led to the popularity of technology-based self-services, with the design of such services becoming increasingly important. Using technology-based services in the public sector as the setting, we identified the key service attributes driving adoption and use of transactional e-government services, and citizens' preference structures across these attributes. After identifying four key attributes, i.e., usability, computer resource requirement, technical support provision and security provision, we conducted a Web-based survey and a conjoint experiment among 2465 citizens. In a two-stage Web-based survey, citizens reported their perceptions about a smartcard technology for transactional e-government services before use, and their use and satisfaction 4 months later. Results showed that the key attributes (noted above) influenced citizens' intentions, subsequent use and satisfaction. In the conjoint experiment, citizens reported their preferences for key service attributes for two transactional e-government services. Further, a cluster analysis uncovered four distinct citizen segments, i.e., balanced, usability-focused, risk-conscious and resource-conservative, that can inform efforts in designing e-government services. A post hoc analysis confirmed the appropriateness of the market segmentation in understanding citizens' adoption and use of transactional e-government services. © 2011 Published by Elsevier B.V.
Pidgeon R.T.,Curtin University Australia
Chemical Geology | Year: 2014
The suggestion that the accumulation of radiation damage in zircons could be used as a dating method was first proposed in the 1950s. In the original technique radiation damage was determined by X-ray diffraction however, this is not suitable for the small sample analysis needed in modern geochronology. It is now possible to measure radiation damage and U and Th contents on micron-sized areas on the polished surface of zircon grains using Raman spectroscopy and SIMS mass spectrometry. This opens the way for a reassessment of the potential of radiation damage ages and the purpose of this contribution is to re-examine the technique through its application to zircons from two granitoids from the Archean Yilgarn Craton and ancient detrital zircons from the Jack Hills in Western Australia. The three examples show internally consistent radiation damage ages that are also in accord with independent geochronological evidence. The 420 ± 110 Ma radiation damage age for the Darling Range granite is coincident with 500-400. Ma biotite Rb-Sr ages in the same region of the Yilgarn Craton. Likewise a tonalite from the Youanmi Terrane in the Craton with a 1650 ± 150 Ma zircon radiation damage age, lies within the domain of a 1600. Ma event recorded by biotite Rb-Sr ages. The Jack Hills zircons have a 1120 ± 130 Ma radiation damage age that is explained by a complex damage accumulation and annealing history culminating in a mild heating event indicated by biotite Ar-Ar ages of about 1140. Ma. The positive results for the three case histories suggest that radiation damage ages could play a useful role in dating low temperature thermal events. © 2013 Elsevier B.V.
White R.W.,University of Mainz |
Powell R.,University of Melbourne |
Holland T.J.B.,University of Cambridge |
Johnson T.E.,University of Mainz |
And 2 more authors.
Journal of Metamorphic Geology | Year: 2014
New activity-composition (a-x) relations for minerals commonly occurring in metapelites are presented for use with the internally consistent thermodynamic dataset of Holland & Powell (, Journal of Metamorphic Geology, 29, 333-383). The a-x relations include a broader consideration of Fe2O3 in minerals, changes to the formalism of several phases and order-disorder in all ferromagnesian minerals where Fe-Mg mixing occurs on multiple sites. The a-x relations for chlorite, biotite, garnet, chloritoid, staurolite, cordierite, orthopyroxene, muscovite, paragonite and margarite have been substantially reparameterized using the approach outlined in the companion paper in this issue. For the first time, the entire set of a-x relations for the common ferromagnesian minerals in metapelitic rocks is parameterized simultaneously, with attention paid to ensuring that they can be used together to calculate phase diagrams of geologically appropriate topology. The a-x relations developed are for use in the Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2-O2 (NCKFMASHTO) system for both subsolidus and suprasolidus conditions. Petrogenetic grids in KFMASH and KFMASHTO are similar in topology to those produced with earlier end-member datasets and a-x relations, but with some notable differences. In particular, in subsolidus equilibria, the FeO/(FeO + MgO) of garnet is now greater than in coexisting staurolite, bringing a number of key staurolite-bearing equilibria into better agreement with inferences from field and petrographic observations. Furthermore, the addition of Fe3+ and Ti to a number of silicate phases allows more plausible equilibria to be calculated in relevant systems. Pseudosections calculated with the new a-x relations are also topologically similar to equivalent diagrams using earlier a-x relations, although with many low variance fields shifting in P-T space to somewhat lower pressure conditions. © 2013 John Wiley & Sons Ltd.
Priddis L.,Curtin University Australia
Paediatric nursing | Year: 2011
The Platt report (Ministry of Health 1959) recommended that hospitals provide for parents to stay with sick children. This review, of how hospitals have or have not followed this guidance, assesses the literature and includes insights into research on the theory of attachment. The authors conclude that, although parents are commonly to be found on wards with sick children, this is not often systematically encouraged or even understood. However, recent initiatives to improve communication between staff and the parents of children admitted to hospital are encouraging.
Coronary CT angiography in calcified coronary plaques: Comparison of diagnostic accuracy between bifurcation angle measurement and coronary lumen assessment for diagnosing significant coronary stenosis
Sun Z.,Curtin University Australia |
Xu L.,Capital Medical University |
Fan Z.,Capital Medical University
International Journal of Cardiology | Year: 2016
Background To investigate the diagnostic value of coronary CT angiography (CCTA) by bifurcation angle measurement in the assessment of calcified plaques compared to conventional coronary lumen analysis. Methods Fifty-three patients with calcified plaques identified on CCTA in the left coronary artery were included in the study. Minimal lumen diameter (MLD) and bifurcation angle between the left anterior descending (LAD) and left circumflex (LCx) arteries were measured and compared between CCTA and invasive coronary angiography (ICA), while the areas under the curves (AUCs) by receiver-operating characteristic curve analysis (ROC) were compared between CCTA and ICA with regard to the diagnostic value of using bifurcation angle as a criterion. Results On a per-vessel assessment, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and 95% confidence interval (CI) with the use of bifurcation angle for determining coronary stenosis were 100% (86%, 100%), 79% (59%, 92%), 81% (62%, 92%), and 100% (85%, 100%) for CCTA, and 100% (86%, 100%), 82% (63%, 94%), 83% (65%, 94%), and 100% (85%, 100%) for ICA, respectively. While the sensitivity and NPV remained unchanged, the specificity and PPV of CCTA by MLD were 33% (21%, 47%) and 43% (31%, 56%). The AUCs by ROC curve analysis for CCTA and ICA bifurcation angle measurements demonstrated no significant difference (p > 0.05, 0.79 vs 0.86, and 0.70 vs 0.68 at the LAD and LCx assessment, respectively). Conclusion Coronary CT angiography by bifurcation angle measurement shows significant improvement in the diagnosis of calcified plaques with diagnostic value comparable to invasive coronary angiography. © 2015 Elsevier Ireland Ltd. All rights reserved.
Lin J.,Curtin University Australia
Medical Physics | Year: 2015
Purpose: In multipinhole single photon emission computed tomography, the overlapping of projections has been used to increase sensitivity. Avoiding artifacts in the reconstructed image associated with projection overlaps (multiplexing) is a critical issue. In our previous report, two types of artifactfree projection overlaps, i.e., projection overlaps that do not lead to artifacts in the reconstructed image, were formally defined and proved, and were validated via simulations. In this work, a new proposition is introduced to extend the previously defined type-II artifact-free projection overlaps so that a broader range of artifact-free overlaps is accommodated. One practical purpose of the new extension is to design a baffle window multipinhole system with artifact-free projection overlaps. Methods: First, the extended type-II artifact-free overlap was theoretically defined and proved. The new proposition accommodates the situation where the extended type-II artifact-free projection overlaps can be produced with incorrectly reconstructed portions in the reconstructed image. Next, to validate the theory, the extended-type-II artifact-free overlaps were employed in designing the multiplexing multipinhole spiral orbit imaging systems with a baffle window. Numerical validations were performed via simulations, where the corresponding 1-pinhole nonmultiplexing reconstruction results were used as the benchmark for artifact-free reconstructions. The mean square error (MSE) was the metric used for comparisons of noise-free reconstructed images. Noisy reconstructions were also performed as part of the validations. Results: Simulation results show that for noise-free reconstructions, the MSEs of the reconstructed images of the artifact-free multiplexing systems are very similar to those of the corresponding 1-pinhole systems. No artifacts were observed in the reconstructed images. Therefore, the testing results for artifact-free multiplexing systems designed using the extended type-II artifact-free overlaps numerically validated the developed theory. Conclusions: First, the extension itself is of theoretical importance because it broadens the selection range for optimizing multiplexing multipinhole designs. Second, the extension has an immediate application: using a baffle window to design a special spiral orbit multipinhole imaging system with projection overlaps in the orbit axial direction. Such an artifact-free baffle window design makes it possible for us to image any axial portion of interest of a long object with projection overlaps to increase sensitivity. © 2015 American Association of Physicists in Medicine.
Do K.D.,Curtin University Australia
IEEE Transactions on Industrial Electronics | Year: 2016
This paper presents a constructive method to design distributed controllers that force a group of N underactuated ships under sea loads to perform a desired synchronization motion tracking task and guarantee no collisions between the ships. First, an observer is designed to globally exponentially estimate the sea loads. Then, the ship dynamics is transformed to an almost spherical form. Smooth or p-times differentiable step functions are next introduced to ensure that the collision avoidance is only active when the ships are in their collision detection zones. For each ship, a dynamical variable is introduced to deal with relaxation of the reference path generation and difficulties caused by underactuation. The control design is based on the above developments, and Lyapunov and backstepping methods. The effectiveness of the proposed results is illustrated through simulations. © 2016 IEEE.
Olatunji O.A.,Curtin University Australia
Proceedings of Institution of Civil Engineers: Management, Procurement and Law | Year: 2014
Building information modelling (BIM) offers a pathway to change in extant technical operations (and business practices) in the architectural, engineering, construction and facilities operations disciplines. Published evidence markedly suggests BIM enhances project outcomes and contract relationships, as though this is a considerable departure from conventional challenges. The overarching question explored in this research - what is this change really about and who does it affect? - is aimed at expounding the relationship between BIM-triggered change and existing change management theories. Although construction disciplines react to change differently, and so are different business structures, the context of change facilitated by BIM is identifiable. It includes behavioural change, process change and role change. Others include skill change, tool change and product change. Furthermore, there are project change scenarios, BIM-triggered change to business models and philosophies and change to legal frameworks. These variables and their descriptors are both interactive and ontologically stratified. Thus, more contemporary studies should reflect the characterisations in these changes. In the end, conclusions are drawn on the legal implications of the different scenarios of BIM changes and potential areas for further research.
Rong Y.,Curtin University Australia
Proceedings of the 2011 Australian Communications Theory Workshop, AusCTW 2011 | Year: 2011
In this paper, we derive the optimal structure of the source precoding matrices and the relay amplifying matrix for a two-way amplify-and-forward multiple-input multiple-output (MIMO) relay communication system where linear minimal mean-squared error (MMSE) receivers are used at both destinations. We show that for a broad class of frequently used objective functions for MIMO communications, the optimal relay and source matrices have a general beamforming structure. Based on this optimal structure, a new iterative algorithm is developed to optimize the relay and source matrices. The performance of the proposed algorithm is demonstrated by numerical simulations. ©2011 IEEE.
Galbreath J.,Curtin University Australia
Business Strategy and the Environment | Year: 2010
This exploratory study sought to investigate how well 98 firms in three industries, across 10 countries, are addressing climate change through five specific governance practices. The findings suggest that non-US firms demonstrate higher performance on the governance dimensions than their US counterparts. Further, by separating firms into low versus high performers on the governance dimensions, some board structure variables, such as number of directors and an independent board chair, were associated with higher performing firms. The study contributes both to institutional and agency theory. For example, coercive isomorphisms in regions of the world, such as Europe, might be driving firms to demonstrate that they are addressing climate change at the governance level in order to gain legitimacy. As for agency theory, this study offers both confirmatory and contradictory results regarding board independence. For example, firms who separated the CEO-board chair role achieved better governance on climate change, while at the same time firms who demonstrated lack of independence with respect to the inside versus outside director ratio also achieved better governance on climate change. This paves the way for additional research in understanding how board structure influences organizational phenomena. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Gucciardi D.F.,Curtin University Australia
Journal of Science and Medicine in Sport | Year: 2016
Objectives: The purpose of this study was to investigate the role of mental toughness in maximising the effect of intentions to perform rehabilitative exercises on behaviour among a sample of people with knee pain. Design: Cross-sectional survey, with a 2-week time-lagged assessment of exercise behaviour. Methods: In total, 193 individuals (nfemale = 107, nmale = 84) aged between 18 and 69 years (M = 30.79, SD = 9.39) participated, with 136 (70.5%) retained at both assessment points. At time 1, participants completed an online, multisection survey that encompassed measures of demographic details, severity of problems associated with the knee (e.g., pain, symptoms), past behaviour, mental toughness, and the theory of planned behaviour constructs (TPB; attitudes, subjective norms, perceived behavioural, intentions). Two weeks later, participants retrospectively reported their exercise behaviour for the past 14 days using an online survey. Results: Moderated regression analyses indicated that mental toughness and its interaction with intention accounted for an additional 3% and 4% of the variance in exercise behaviour, respectively. Past behaviour, attitudes, and mental toughness all had direct effects on behaviour, alongside a meaningful interaction between intentions and mental toughness. Specifically, intentions had a stronger effect on exercise behaviour among those individuals high in mental toughness compared to those low in this personal resource. Conclusions: The results of this study shed new light on the intention-behaviour gap by indicating that mental toughness increases the likelihood that intention is translated into action. © 2015 Sports Medicine Australia.
Lindwall M.,Gothenburg University |
Larsman P.,Gothenburg University |
Hagger M.S.,Curtin University Australia
Health Psychology | Year: 2011
Objective: The aim of this prospective study was to investigate the reciprocal nature of the physical activity-depressive symptoms relationship in 17,593 older adults from 11 European countries older adults (M age = 64.07, SD = 9.58) across two-year follow-up. Also, gender and age were examined as potential moderators of this relation. Method: A two-wave cross-lagged panel design and latent change score models with structural equation modeling was used to analyze data. Depressive symptoms were measured at baseline (T1) and follow-up (T2) using the EURO-D scale, capturing the two factors of affective suffering and motivation. Physical activity was measured at T1 and T2 as frequency of moderate physical activity and vigorous physical activity. Results: Cross-sectional latent variable analyses revealed that higher levels of physical activity at T1 and T2 were associated with lower levels of affective suffering and motivation at T1 and T2. Physical activity at T1 was significantly associated with affective suffering and motivation at T2. The relations of depressive symptoms at T1 with physical activity at T2 were not significant. However, a cross-lagged model showed best model fit, supporting a reciprocal prospective relationship between physical activity and depressive symptoms in older adults. Latent change in depressive symptoms factors was related to latent change in physical activity indicating complex and dynamic associations across time. Conclusions: Regular physical activity may be a valuable tool in the prevention of future depressive symptoms in older adults, and depressive symptoms may also prevent older adults from engaging in regular physical activity. © 2011 American Psychological Association.
O'Leary M.J.,Curtin University Australia |
Hearty P.J.,University of North Carolina at Wilmington |
Thompson W.G.,Woods Hole Oceanographic Institution |
Raymo M.E.,Lamont Doherty Earth Observatory |
And 2 more authors.
Nature Geoscience | Year: 2013
During the last interglacial period, 127-116 kyr ago, global mean sea level reached a peak of 5-9m above present-day sea level. However, the exact timing and magnitude of ice sheet collapse that contributed to the sea-level highstand is unclear. Here we explore this timing using stratigraphic and geomorphic mapping and uranium-series geochronology of fossil coral reefs and geophysical modelling of sea-level records from Western Australia. We show that between 127 and 119 kyr ago, eustatic sea level remained relatively stable at about 3-4 m above present sea level. However, stratigraphically younger fossil corals with U-series ages of 118.1±1.4 kyr are observed at elevations of up to 9.5 m above present mean sea level. Accounting for glacial isostatic adjustment and localized tectonics, we conclude that eustatic sea level rose to about 9 m above present at the end of the last interglacial. We suggest that in the last few thousand years of the interglacial, a critical ice sheet stability threshold was crossed, resulting in the catastrophic collapse of polar ice sheets and substantial sea-level rise. © 2013 Macmillan Publishers Limited. All rights reserved.
Mudhoo A.,University of Mauritius |
Garg V.K.,Guru Jambheshwar University of Science and Technology |
Wang S.,Curtin University Australia
Environmental Chemistry Letters | Year: 2012
Industrialization and urbanization have resulted in increased releases of toxic heavy metals into the natural environment comprising soils, lakes, rivers, groundwaters and oceans. Research on biosorption of heavy metals has led to the identification of a number of microbial biomass types that are extremely effective in bioconcentrating metals. Biosorption is the binding and concentration of adsorbate from aqueous solutions by certain types of inactive and dead microbial biomass. The novel types of biosorbents presently reviewed are grouped under fungal biomass, biomass of non-living, dried brown marine algae, agricultural wastes and residues, composite chitosan biosorbent prepared by coating chitosan, cellulose-based sorbents and bacterial strains. The reports discussed in this review collectively suggest the promise of biosorption as a novel and green bioremediation technique for heavy metal pollutants from contaminated natural waters and wastewaters. © 2011 Springer-Verlag.
Coolen M.J.L.,Woods Hole Oceanographic Institution |
Coolen M.J.L.,Curtin University Australia |
Orsi W.D.,Woods Hole Oceanographic Institution
Frontiers in Microbiology | Year: 2015
Thawing of permafrost soils is expected to stimulate microbial decomposition and respiration of sequestered carbon. This could, in turn, increase atmospheric concentrations of greenhouse gasses, such as carbon dioxide and methane, and create a positive feedback to climate warming. Recent metagenomic studies suggest that permafrost has a large metabolic potential for carbon processing, including pathways for fermentation and methanogenesis. Here, we performed a pilot study using ultrahigh throughput Illumina HiSeq sequencing of reverse transcribed messenger RNA to obtain a detailed overview of active metabolic pathways and responsible organisms in up to 70 cm deep permafrost soils at a moist acidic tundra location in Arctic Alaska. The transcriptional response of the permafrost microbial community was compared before and after 11 days of thaw. In general, the transcriptional profile under frozen conditions suggests a dominance of stress responses, survival strategies, and maintenance processes, whereas upon thaw a rapid enzymatic response to decomposing soil organic matter (SOM) was observed. Bacteroidetes, Firmicutes, ascomycete fungi, and methanogens were responsible for largest transcriptional response upon thaw. Transcripts indicative of heterotrophic methanogenic pathways utilizing acetate, methanol, and methylamine were found predominantly in the permafrost table after thaw. Furthermore, transcripts involved in acetogenesis were expressed exclusively after thaw suggesting that acetogenic bacteria are a potential source of acetate for acetoclastic methanogenesis in freshly thawed permafrost. Metatranscriptomics is shown here to be a useful approach for inferring the activity of permafrost microbes that has potential to improve our understanding of permafrost SOM bioavailability and biogeochemical mechanisms contributing to greenhouse gas emissions as a result of permafrost thaw. © 2015 Coolen and Orsi.
Dong C.,Curtin University Australia
Composites Part B: Engineering | Year: 2016
A study on the flexural behaviours of the of glass and carbon fibre reinforced epoxy hybrid composites is presented in this paper. Two types of glass fibres: S-2 and E, and two types of carbon fibres: T700S and P-100 are investigated. The flexural strength is obtained using an approach based on finite element analysis. Three compressive strength models: Lo-Chim, Budiansky and the shear models are used to obtain the flexural strengths. It is shown from the results that when shear failure occurs, the flexural strength is 20-30% lower compared to other failure modes. © 2016 Elsevier Ltd. All rights reserved.
Williams M.E.,Curtin University Australia |
Thompson S.C.,University of Western Australia
Journal of Immigrant and Minority Health | Year: 2011
With large numbers of refugee arrivals and numerous barriers to accessing services it is especially important that resources are efficiently and effectively directed to address the health needs of refugees. Ten databases were utilised to conduct the review, returning 156 titles which were assessed for validity based on specified criteria. The 14 critically appraised articles included in this review consist of experimental research and discussions on best practice. Articles consistently demonstrated the benefit of community-based mental health service in improving mental health outcomes. Themes of cultural awareness, language, setting, and post-migration stressors emerged across the articles. In addition, the studies also point to the gaps in research of a longitudinal nature and ones that deal with scattered populations post migration. Communitybased interventions proved valuable for improving the mental health of refugees. However, additional interventions and evaluations are required to draw consistent and conclusive judgments on best practice in dealing with refugee mental health issues. © Springer Science+Business Media, LLC 2010.
Simpson J.,Curtin University Australia
European Journal of Combinatorics | Year: 2013
We give a short proof of a recent result of Mansouretal.(2012)  concerning the recurrence u (n, k) = u (n - 1, k - 1) + (an-1 + bk) u (n - 1, k) © 2012.
Hu P.J.-H.,University of Utah |
Hui W.,Curtin University Australia
Decision Support Systems | Year: 2012
We examine students' learning effectiveness and satisfaction in technology-mediated learning by analyzing how it influences the underlying learning process, with a focus on the role of learning engagement. We propose a structural model that explains students' learning effectiveness and satisfaction, and then empirically test that model and the associated hypotheses with an experiment involving 212 university students learning Adobe Photoshop. Our experimental data show that the effects of technology-mediated learning are mostly mediated by learning engagement. In particular, the use of preprogrammed video contents to deliver learning materials negatively affects learning engagement, which in turn reduces perceived learning effectiveness and satisfaction. However, technology-mediated learning appears to have no significant effects, direct or moderating, on learning effectiveness or satisfaction. These findings have several important implications for technology-mediated learning research and practice. © 2012 Elsevier B.V. All rights reserved.
Lu C.,Curtin University Australia
International Journal of Materials Research | Year: 2011
In contrast to their bulk samples, there seems no obvious size effect on the strength of brittle materials at micro-and nano-scales although some degree of scatter exists in experimental measurements. In this paper, current advances on the statistical analysis of available strength data of materials at micro-and nano-scales have been briefly reviewed. It is shown that, by means of a minimum information criterion, a better statistical model can be selected for quantifying the intrinsic mechanical properties of micro-and nanostructured materials and further applied for extracting the optimal information from those imperfect experimental data obtained with recently nano-mechanical testing techniques. Also discussed is the defect tolerance of brittle materials at micro-and nano-scales, which may be due to the collective interaction of flaws in a non-traditional sense. © Carl Hanser Verlag GmbH & Co. KG.
Dam H.H.,Curtin University Australia
International Journal of Innovative Computing, Information and Control | Year: 2013
Variable fractional delay (VFD) filters are useful for various signal processing and communication applications with frequency characteristics such as fractional delays to be varied online. In this paper, we investigate the design of VFD filters with discrete coefficients as a means of achieving low complexity and efficient hardware implementation. The optimization problem with minimax criterion is formulated as a mixed integer programming problem with a non-linear cost function and continuous constraints. An efficient optimization procedure is proposed to tackle the design problem that includes a combination of the branch and bound method and an adaptive scheme for discretization. Design examples are given to demonstrate the effectiveness of the proposed algorithm. © 2013 ICIC International.
Clark C.,Curtin University Australia |
Hand M.,University of Adelaide
Gondwana Research | Year: 2010
The pressure-temperature (P-T) path for the Palaeoproterozoic Willyama Supergroup rocks in the Olary Domain, South Australia has been reconstructed through detailed petrographic observations, in conjunction with calculation of compositionally specific P-T pseudosections of metapelitic rock units and Sm-Nd garnet geochronology. The P-T path for the Willyama Complex has historically been interpreted to follow a single anticlockwise path, however the results of this study demonstrate that this path can be better described by two metamorphic events (M 1 and M 2) separated by 1100 Ma. The M 1 event occurred at c. 1600 Ma and was associated with high temperature-low pressure metamorphism. Sm-Nd garnet geochronology constrains the timing of garnet growth at c. 1585 Ma. The growth of large andalusite porphroblasts during M 1 exerted a first order control on the bulk composition during the subsequent M 2 event. Mineral chemistries coupled with quantitative phase diagrams constrain peak conditions to be in the order of c. 550°C and 5.5 kbar during M 2. The identification of two metamorphic events calls into question interpretations of metamorphic core complex formation and the single anticlockwise P-T paths being associated with the early stages of the tectonic evolution of the terrain. © 2009 Elsevier B.V. All rights reserved.
Mohajer N.,Curtin University Australia
Health education research | Year: 2010
Growing numbers of adolescents are marginalized by social factors beyond their control, leading to poor health outcomes for their families and future generations. Although the role of the social determinants of health has been recognized for many years, there is a gap in our knowledge about the strategies needed to address these factors in health promotion. Drawing on a review of literature on health promotion for marginalized and out-of-school adolescents, this paper highlights some urgent areas of focus for researchers and policy makers addressing adolescent health. Social determinants of health affecting marginalized adolescents identified by the review were education, gender, identity, homelessness, poverty, family structure, culture, religion and perceived racism, yet there is little solid evidence as to how to best address these factors. More systematic research, evaluation and global debate about long-term solutions to chronic poverty, lack of education and social marginalization are needed to break the cycle of ill health among vulnerable adolescents.
Liaw S.-S.,Washington State University |
Zhou S.,Washington State University |
Wu H.,Curtin University Australia |
Garcia-Perez M.,Washington State University
Fuel | Year: 2013
This paper investigates the effect of thermal pretreatment temperatures between 200 and 370 °C on the yield and composition of products (bio-charm gasm water and organics) obtained when Douglas-fir wood was subsequently pyrolyzed in an auger reactor at 500 °C. The yield of products was reported for the pretreatment and pyrolysis steps separately, and for the two steps added. The maximum yield of bio-oils achieved without pretreatment was close to 59 mass%. A decrease in total liquid yield was observed when the biomass was pretreated at 300 °C. At higher temperatures, the yields of Douglas-fir primary degradation products (lignin oligomers, anhydrosugars and alkylated and methoxylated phenols) decreased. The overall water yield increased gradually to 14 mass% at a pretreatment temperature of 290 °C. The yield of lignin oligomers also decreased as the pretreatment temperature increased. A drastic reduction in the yield of methoxylated phenols derived from guaiacyl (G) was observed when the biomass was pretreated at temperatures over 300 °C. This drastic reduction in the yield of methoxylated lignin derivatives can be explained by the formation of liquid intermediates that facilitate the formation of ionic species, enhancing dehydration reactions leading to the production of o-quinone methide intermediates critical for bio-char formation. © 2012 Elsevier Ltd. All rights reserved.
Jiang S.P.,Curtin University Australia
International Journal of Hydrogen Energy | Year: 2012
Solid oxide fuel cells (SOFCs) are the most efficient devices for the direct conversion of the chemical energy stored in fuels such as hydrogen and hydrocarbons into electricity. The development of highly efficient and robust SOFCs requires cathodes and anodes with high electrocatalytic activity for O 2 reduction and direct oxidation of hydrocarbon fuels, respectively. Nanoscale engineering of electrode structures via metal salt solution impregnation or infiltration attracts increasing attention as the most effective way to develop highly active and advanced electrode structures for SOFCs. The infiltration method opens a new horizon in the advanced electrode development as the method expands the set of variable electrode materials combinations with the elimination of thermal expansion mismatch and the suppression of potential detrimental reactions between electrode and electrolyte materials. In this article, the advances and challenges in the development of nanoscale and nano-structured electrodes and the fundamental understanding of the remarkable enhancement in the electrode performance are reviewed and discussed with primary focus on the progress and status of the field in the last 5 years. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Yang X.,China University of Mining and Technology |
Aldrich C.,Curtin University Australia
International Journal of Mining Science and Technology | Year: 2013
Coal flotation is widely used to separate commercially valuable coal from the fine ore slurry, and is an industrial process with nonlinear, multivariable, time-varying and long time-delay characteristics. The online detection of ash content of products as the operation performance evaluation in the flotation system is extraordinarily difficult because of the low solid content and numerous micro-bubbles in the slurry. Moreover, it is time-consuming by manual analysis. Consequently, the optimal separation is not usually maintained. A novel technique, called the neuro-immune algorithm (NIA) inspired by the biological nervous and immune systems, is presented in this paper for predicting the ash content of clean coal and performing the optimizing control to the coal flotation system. The proposed algorithm integrates the deeply-studied artificial neural network (ANN) and the developing artificial immune system (AIS). A two-layer back-propagation network was constructed offline based on the historical process data under the best system situation, using five parameters: the flow and the density of raw slurry, the input flows of water, the kerosene and the GF oil, as the inputs and the ash content of clean coal as the output. The immune cell of AIS is made up of six parameters above as the antigen. The cytokine based clone selection algorithm is used to produce the relative antibody. The detailed computation procedures about the hybrid neuro-immune algorithm are minutely discussed. The ash content of clean coal was predicted by NIA using the practical process data s: (308.6 174.7 146.1 43.6 4.0 9.4), and the absolute difference between the actual and computed ash content values was 0.0967%. The optimizing control on NIA was simulated considering two different situations where the ash content of clean coal was controlled downward from 10.00% or upward from 9.20% predicted by ANN to the target value 9.50%. The results indicate that the target ash content and the value of controlling parameters are obtained after several control cycles. © 2013 Published by Elsevier B.V. on behalf of China University of Mining & Technology.
Voon D.,Monash University |
Hasking P.,Curtin University Australia |
Hasking P.,Monash University |
Martin G.,University of Queensland
Journal of Abnormal Psychology | Year: 2014
This longitudinal study examines the extent to which changes in the use of cognitive reappraisal, expressive suppression, and rumination impact on frequency, duration, and medical severity of nonsuicidal self-injury (NSSI) among adolescents. Data from 3,143 predominantly female high school students recruited from 40 Australian secondary schools were analyzed using latent growth curve modeling. Significant differences in the psychological factors between the 555 participants with a history of NSSI and non-self-injurers were reported at baseline. Self-injurers experienced significantly greater accumulation of life stressors over time compared with non-self-injurers. After controlling for adverse life events, psychological distress and other emotion regulation strategies, use of cognitive reappraisal at baseline was associated with less severe NSSI presentations, and slower growth in medical severity of NSSI over time. Findings indicate that while both cohorts have similar emotion regulation trajectories, adolescents who self-injure start off at a disadvantage and have a propensity to engage in less helpful processes that tend to heighten negative emotional states. Results recommend increasing focus on improving adolescents' frequency and skills in use of cognitive reappraisal in efforts to reduce NSSI among this population. © 2014 American Psychological Association.
Aguilera R.F.,Curtin University Australia
Energy Policy | Year: 2014
Concerns about the costs of developing oil and gas from conventional and unconventional formations have led many commentators to assume that increasing prices are in the offing and may be a limiting factor for economic growth. Historically, production costs have fluctuated as influenced by the cost-increasing effects of depletion versus the cost-reducing effects of technological progress. This paper aims to review several methods for assessing current and long-term costs. Despite the uncertainty of such estimation, evidence shows that production costs in the foreseeable future might not increase dramatically and actually could decrease as petroleum development methods improve and additional supplies come online. Recent examples include the commercially viable production of unconventional oil and gas resources that has kept energy prices contained. © 2013 Elsevier Ltd.
Cheng A.S.K.,Hong Kong Polytechnic University |
Lee H.C.,Curtin University Australia
Transportation Research Part F: Traffic Psychology and Behaviour | Year: 2012
The purposes of this study were to identify the relationships between the risk-taking behavior, response inhibition, and risky motorcycle riding behavior of commuter motorcyclists with different levels of impulsivity, and to examine how these behaviors contribute to motorcycle accidents. A total of 255 Chinese commuter motorcyclists were recruited for this study. Their levels of impulsivity were classified according to the Chinese Barratt Impulsiveness Scale version 11th. Their risk-taking behavior was assessed by the Balloon Analogue Risk Task and their response inhibition was assessed by the Chinese version of the Stroop test Victoria version. The Chinese Motorcycle Rider Driving Violation Scale was used to assess risky motorcycle riding behaviors. Results showed that impulsivity was associated with risk-taking behavior and risky motorcycle riding. Highly impulsive motorcyclists carry out more risk-taking behaviors and are less able to inhibit responses than those with low impulsivity. Motorcyclists with medium impulsivity (OR, 4.74; 95% CI, 1.91-11.39) and those with high impulsivity (OR, 4.91; 95% CI, 2.34-10.24) were about 5 times more likely to be actively involved in motorcycle accidents than those with low impulsivity. Postlicense motorcycle riding experience and risky motorcycle riding behavior were two significant predictors of motorcycle traffic accidents after controlling for other sociodemographic variables. These results can facilitate the development of interventions, including the training and testing of motorcyclists, public education, and mass media messages about traffic risk. © 2012 Elsevier Ltd. All rights reserved.
Thern E.R.,Curtin University Australia |
Nelson D.R.,University of Western Sydney
Precambrian Research | Year: 2012
A multivariate approach using a similarity matrix derived from >5500 U-Pb zircon analyses was used to investigate the complex and overlapping detrital zircon age structure within ca. 3Ga metasedimentary rocks from the Yilgarn Craton, Western Australia. Detrital zircon analyses were grouped by their 207Pb/ 206Pb dates using a robust Chi-square grouping method which produced 74 Yilgarn-wide age groups from a pool of >3500 analyses and that were correlated between different metasedimentary rocks. Principal component analysis (PCA) was then used on a calculated similarity matrix of >65 samples which contained these age groups. PCA indicates that the main age populations of the detrital zircons in the ca. 3Ga metasedimentary rocks were derived in varying portions from the Narryer and Yarlarweelor Gneiss Complexes. Differences between the age structure of >3.9Ga zircon populations within the Mt. Alfred metasedimentary rocks with those from Mt. Narryer, Jack Hills and Maynard Hills localities is best explained by their derivation from two Hadean terranes which were joined by ca. 3.7Ga. © 2011 Elsevier B.V.
Evans K.A.,Curtin University Australia |
Elburg M.A.,Ghent University |
Elburg M.A.,University of KwaZulu - Natal |
Kamenetsky V.S.,University of Tasmania
Geology | Year: 2012
The subarc mantle is a primary control on the composition of arc magmas and the formation of arc-related ore deposits. Elevated ferric iron contents in arc lavas have been interpreted as a record of subarc mantle that is oxidized relative to mid-oceanic ridge basalt (MORB), but this conclusion is controversial. Measurements of spinel compositions in primitive arc lavas imply an arc magma source 1-4 log units more oxidized than MORB and ocean island basalts analyzed using the same technique. Samples from seven arcs show a significant correlation (P < 0.0005) between redox budget, subduction zone convergence rate, and subduction zone age. These results support the notion of oxidized arc lavas in the mantle source zone, but resolution of contradictory evidence regarding subarc mantle redox state requires further work. © 2012 Geological Society of America.
Harris P.,Center for Health Equity Training |
Spickett J.,Curtin University Australia
Environmental Impact Assessment Review | Year: 2011
This article provides an overview of Health Impact Assessment (HIA) within Australia. We discuss the development and current position of HIA and offer some directions for HIA's progression. Since the early 1990s HIA activity in Australia has increased and diversified in application and practice. This article first highlights the emergent streams of HIA practice across environmental, policy and health equity foci, and how these have developed within Australia. The article then provides summaries of current practice provided by each Australian state and territory. We then offer some insight into current issues that require further progression or resolution if HIA is to progress effectively in Australia. This progress rests both on developing broad system support for HIA across government, led by the health sector, and developing system capacity to undertake, commission or review HIAs. We argue that a unified and clear HIA approach is required as a prerequisite to gaining the understanding and support for HIA in the public and private sectors and the wider community. © 2010 Elsevier Inc.
Coombe D.R.,Curtin University Australia |
Kett W.C.,Glycan Biosciences Inc.
Handbook of Experimental Pharmacology | Year: 2012
Explorations of the therapeutic potential of heparin mimetics, anionic compounds that are analogues of glycosaminoglycans (GAGs), have gone hand-in-hand with the emergence of understanding as to the role of GAGs in many essential biological processes. A myriad of structurally different heparin mimetics have been prepared and examined in many diverse applications. They range in complexity from heterogeneous polysaccharides that have been chemically sulphated to well-defined compounds, designed in part to mimic the natural ligand, but with binding specificity and potency increased by conjugation to non-carbohydrate pharmacophores. The maturity of the field is illustrated by the seven heparin mimetics that have achieved marketing approval and there are several more in late-stage clinical development. An overview of the structural determinants of heparin mimetics is presented together with an indication of their activities. The challenges in developing heparin mimetics as drugs, specificity and potential toxicity issues, are highlighted. Finally, the development path of three structurally very different mimetics, PI-88 ®, GMI-1070 and RGTAs, each of which is in clinical trials, is described. © 2012 Springer-Verlag Berlin Heidelberg.
Jiang S.P.,Curtin University Australia
Journal of Materials Chemistry A | Year: 2014
There are significant technological and economical advantages for operating a proton exchange membrane fuel cell (PEMFC) at temperatures above 100-150 °C. One of the key components in the development of high temperature PEMFCs is the proton exchange membrane (PEM). The PEM not only needs to be highly stable in the harsh chemical and physical environment in fuel cells, but also needs to possess high proton conductivity at elevated temperatures and under low humidity conditions. In this paper, the research activity and progress in the development of high temperature PEMs will be briefly reviewed but the main emphasis will be on the development of unsupported and functionalized nano and mesoporous structured inorganic materials such as TiO2, Fe 2O3, Al2O3 and SiO2 as high temperature PEMs for fuel cells. Among various inorganic proton conducting materials, heteropolyacid (e.g., H3PW12O40 or HPW) functionalized mesoporous silica, HPW-meso-silica, shows particularly promising potential as new PEMs for fuel cells. The challenge and prospects of the development of functionalized mesoporous silica based PEMs for fuel cells operated at high temperatures (300-450 °C) are discussed. This journal is © the Partner Organisations 2014.
Zhu W.,Xiangtan University |
Yang L.,Xiangtan University |
Guo J.W.,Xiangtan University |
Zhou Y.C.,Xiangtan University |
Lu C.,Curtin University Australia
International Journal of Plasticity | Year: 2015
Determination of interfacial adhesion energies of thermal barrier coatings is important for understanding failure mechanisms and predicting their lifetime. Combined compression test with a cohesive zone finite element model, it is shown that the interfacial adhesion energy is in the range of 100-130 J/m2. Based on the nonlinear delamination theory, the critical interfacial adhesion energy of delamination is 120 J/m2 and the corresponding loading phase angle is -56°. With the increase of the half-length of the crack, the crack propagation tends to be steady with a steady-state interface energy release rate of 150 J/m2, and delamination experiences almost pure mode II. These results obtained from finite element simulations and theoretical analyses are in good agreement with the available values determined by other testing methods reported in the literatures, which confirms the validity of this method. © 2014 Elsevier Ltd.
Gucciardi D.F.,Curtin University Australia |
Jackson B.,University of Western Australia
Journal of Science and Medicine in Sport | Year: 2015
Objectives: Fostering individuals' long-term participation in activities that promote positive development such as organised sport is an important agenda for research and practice. We integrated the theories of planned behaviour (TPB) and basic psychological needs (BPN) to identify factors associated with young adults' continuation in organised sport over a 12-month period. Design: Prospective study, including an online psycho-social assessment at Time 1 and an assessment of continuation in sport approximately 12 months later. Methods: Participants (N=. 292) aged between 17 and 21 years (M=. 18.03; SD. =. 1.29) completed an online survey assessing the theories of planned behaviour and basic psychological needs constructs. Bayesian structural equation modelling (BSEM) was employed to test the hypothesised theoretical sequence, using informative priors for structural relations based on empirical and theoretical expectations. Results: The analyses revealed support for the robustness of the hypothesised theoretical model in terms of the pattern of relations as well as the direction and strength of associations among the constructs derived from quantitative summaries of existing research and theoretical expectations. The satisfaction of basic psychological needs was associated with more positive attitudes, higher levels of perceived behavioural control, and more favourable subjective norms; positive attitudes and perceived behavioural control were associated with higher behavioural intentions; and both intentions and perceived behavioural control predicted sport continuation. Conclusions: This study demonstrated the utility of Bayesian structural equation modelling for testing the robustness of an integrated theoretical model, which is informed by empirical evidence from meta-analyses and theoretical expectations, for understanding sport continuation. © 2013.
Hall S.,Curtin University Australia
Renewable Energy | Year: 2014
Green Building has been a large focus for the construction industry, with Green Star certified commercial buildings becoming the new standard for commercial office buildings. However there has been little focus on the improvement of existing buildings, and many of Australia's capital cities have ageing building stock that is not operating efficiently and contributing to the nation's growing greenhouse gas emissions.Retrofitting existing buildings for energy efficiency is receiving more attention across Australia, with grants and funding to incentivise owners to find energy efficient solutions for buildings. However it is important that optimising performance of these buildings considers the impact on occupants. Australians spend the majority of their day indoors and the quality of the indoor environment can have a major impact on the health and productivity of workers.This paper covers the development of a tool for a project sponsored by the Sustainable Built Environment National Research Centre to assist building stakeholders identify key energy performance issues with their buildings. The tool explores 5 key areas in buildings that influence energy performance: design elements, building management, occupant experience, agreements and culture and indoor environment quality.The paper explains the development of the tool and some surprising results from the first trial on the tenancy for a 28 year old commercial building in the Perth CBD that underwent a Green Star interiors fit-out. © 2013 Elsevier Ltd.
Aguilera R.F.,Curtin University Australia
Applied Energy | Year: 2014
As the Asia Pacific region continues to experience rapid economic growth, natural gas may have an important role in satisfying regional demand and transitioning to a low carbon economy. In this study, a Global Energy Market Model (GEM) is used to analyze the market shares of gases, liquids and solids in the Asia Pacific. The model matches the historical energy mix from 1850 to 2010 as well as the historical hydrogen to carbon (H/. C) ratio. The GEM is then used to present scenarios of the Asia Pacific energy mix and H/. C ratio to the year 2030. The scenarios vary according to policies and technologies that either encourage or discourage gas use. Estimates of conventional and unconventional gas quantities and costs are also presented, partly with a Variable Shape Distribution Model (VSD) and supply curves. The Asia Pacific is found to have vast natural gas resources, though suitable policies are needed to develop the potential. For instance, incentives will be necessary for investment in gas and LNG technology, as increased market share will not occur if investment does not take place in a timely fashion. In addition, it is important that government intervention not create disincentives for development of the regional gas and LNG industries. © 2013 Elsevier Ltd.
Kitoko V.,Curtin University Australia
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2011
In this paper we evaluate the physiological performance of a silver-silver chloride dry electrode with bristle (B-Electrode) in recording EEG data. For this purpose, we compare the performance of the bristle electrode in recording EEG data with the standard wet gold-plated cup electrode (G-Electrode) using two different brain state change tasks including resting condition with eyes-closed and performing mathematical task with eyes-open. Using a 2 channel recording device, eyes-closed command data were collected from each of 6 participants for a period of 20 sec and the same procedure was applied for the mathematical calculation task. These data were used for statistical and classification analyse. Although, B-electrode has shown a slightly higher performance compared with G-electrode in both tasks, but analyse did not reveal any significant differences between both electrodes in all six subjects tested.
Shafiei S.,Azad University |
Salim R.A.,Curtin University Australia
Energy Policy | Year: 2014
This paper attempts to explore the determinants of CO2 emissions using the STIRPAT model and data from 1980 to 2011 for OECD countries. The empirical results show that non-renewable energy consumption increases CO2 emissions, whereas renewable energy consumption decreases CO2 emissions. Further, the results support the existence of an environmental Kuznets curve between urbanisation and CO2 emissions, implying that at higher levels of urbanisation, the environmental impact decreases. Therefore, the overall evidence suggests that policy makers should focus on urban planning as well as clean energy development to make substantial contributions to both reducing non-renewable energy use and mitigating climate change. © 2013.
Herzog G.,Tyndall National Institute |
Nolan M.-T.,Tyndall National Institute |
Arrigan D.W.M.,Curtin University Australia
Electrochemistry Communications | Year: 2011
The electrochemical behaviour of haemoglobin denatured using different concentrations of urea was investigated at the liquid-liquid interface. The reverse peak current varied with the concentration of urea, allowing the building of the unfolding curve, which compares well with UV-Vis absorbance results. Thermodynamic parameters, such as the change in free energy of folding in water, ΔG w, and the index of the compactness of the protein, m, were extracted from the experimental data. The work here presents a simple electrochemical method for the study of protein unfolding by electrochemistry at the liquid-liquid interface. © 2011 Elsevier B.V. All rights reserved.
Mattiussi A.,University of Udine |
Rosano M.,Curtin University Australia |
Simeoni P.,University of Udine
Decision Support Systems | Year: 2014
A framework for an energy supply decision support system (DSS) for sustainable plant design and production is presented in this paper, utilising an innovative use of multi-objective and multi-attribute decision-making (MODM, MADM) modelling together with impact assessment (IA) of the emission outputs. The mathematical model has been applied within an eco-industrial park (EIP) setting and includes three steps. First, an assessment of the total EIP emissions' inventory and impacts is conducted; the second step, focusing on the sustainability benefits of combined heating and power (CHP) plants and photovoltaic technologies, developed a multi-objective mathematical model including both economic and environmental objectives in a Pareto-frontier optimisation analysis. Four different scenarios involving combinations of CHP plants (internal combustion engine, gas turbine, micro-turbines and fuel cells) and two types of PV plant (monocrystalline and polycrystalline) were evaluated. The third step utilises a MADM methodology - the analytic hierarchy process (AHP) - for selecting the best alternative among the Pareto-frontier efficient solutions. This model has been applied to a case study of an EIP located in Perth (Kwinana Industrial Area - KIA), Western Australia. © 2013 Elsevier B.V.
Love P.E.D.,Curtin University Australia
Procedia Engineering | Year: 2011
Infrastructure projects regularly experience cost and schedule overruns. Research led by Flyvberg has suggested that misrepresentation and optimum bias are primary causes for overruns. While Flyvberg's research has made a significant contribution to ameliorating understanding as to why economic infrastructure projects experience overruns, it does not adequately explain why this is the case for such social infrastructure. In addressing this shortcoming, a case study is used to determine the intermediary events and actions that contributed to it experiencing a project cost overrun. The events and actions that contributed overruns are identified and analyzed. The analysis of the case study findings has led to the propagation of nomological framework for social infrastructure project overruns.
Rong Y.,Curtin University Australia
IEEE Transactions on Communications | Year: 2010
In this letter we propose linear non-regenerative multicarrier multiple-input multiple-output (MIMO) relay technique that aims to minimize the mean-squared error (MSE) of the signal waveform estimation at the destination. We generalize the existing result on the structure of the optimal relay amplifying matrix by considering the direct source-destination link. To minimize the MSE, a power loading algorithm is developed which has a significantly reduced computational complexity compared with existing techniques. © 2010 IEEE.
Thomas L.E.,Curtin University Australia
Building Research and Information | Year: 2010
Existing buildings present the best opportunity for reducing greenhouse gas emissions in developed economies, given that only 2-3% of the building stock is newly built each year. Insights from a post-occupancy evaluation of a large-scale refurbishment project of a head office building in Sydney, Australia, are presented to inform future refurbishment strategies. The study evaluates occupant satisfaction and energy performance, and elicits influencing factors arising from the design process and interventions, ongoing building management, and operational performance. Occupants returned a high level of satisfaction across the range of environmental variables for overall comfort, temperature, lighting, and air quality as well as perceived productivity and health. These outcomes highlight the importance of improving indoor environmental quality for occupants particularly through increased fresh air, daylight, glare control, access to views, and noise management. The positive results reinforce the value of an integrated and user-responsive approach that was adopted for building design, development, and management. The reduction in operational energy (in this project, coupled with carbon reduction) as a consequence of refurbishment and positive user feedback demonstrates the potential to future-proof existing buildings in the context of climate change. © 2010 Taylor & Francis.
Jayaweera D.,Curtin University Australia
IEEE Transactions on Power Systems | Year: 2015
Security enhancement of distribution networks are constrained with multiple causes including limited availability of network resources and high penetration of intermittent distributed generation. In that context, this paper proposes a new methodology to enhance the security of power supply in a distribution network by strategically integrating plug-in hybrid electric vehicle (PHEV) micro grids based on the nodal criticality. The nodal criticality is assessed by integrating operational uncertainties of events into samples of Monte Carlo simulation and then classifying load interruptions on the basis of their magnitudes and frequencies. The load shedding due to criticality of system stress is classified into arrays of clusters on the basis of magnitudes of interrupted loads. The critical clusters that provide the largest disturbances to nodal loads are used as the reference capacities of PHEV micro grids to mitigate impacts. Case studies are performed by applying the methodology into a realistic model of a distribution network. Results depict that the proposed methodology can improve the system-wide security of supply. There are some nodes of which the security of supply can be improved significantly. The levels of improvement in security of supply of nodes are not consistent and some nodes can also receive marginal improvements. © 1969-2012 IEEE.
Shahin M.A.,Curtin University Australia
Journal of Constructional Steel Research | Year: 2014
In this study, the feasibility of using evolutionary computing for modelling ultimate pure bending of steel circular tubes was investigated. The behaviour of steel circular tubes under pure bending is complex and highly non-linear, and the literature has a number of solutions, most of which are difficult to use in routine design practice as they do not provide a closed-form solution. This work presents a new approach, based on evolutionary polynomial regression (EPR), for developing a simple and easy-to-use formula for prediction of ultimate pure bending of steel circular tubes. The EPR model was calibrated and verified using a large database that was obtained from the literature and comprises a series of 104 pure bending tests conducted on fabricated and cold-formed tubes. The predicted ultimate pure bending of steel circular tubes using this model can be obtained from a number of inputs including the tube thickness, tube diameter, steel yield strength and modulus of elasticity of steel. A sensitivity analysis was carried out on the developed EPR model to investigate the model generalisation ability (or robustness) and relative importance of model inputs to its output. Predictions from the EPR model were compared with those obtained from artificial neural network (ANN) models previously developed by the authors, as well as most available codes and standards. The results indicate that the EPR model is capable of predicting the ultimate pure bending of steel circular tubes with a high degree of accuracy and outperforms most available codes and standards. The results also indicate that the performance of the EPR model agrees well with that of the previously developed ANN models. It was also shown that the EPR model was able to learn the complex relationship between the ultimate pure bending and most influencing factors, and render this knowledge in the form of a simple and transparent function that can be readily used by practising engineers. The advantages of the proposed EPR technique over the ANN approach were also addressed. © 2013 Elsevier Ltd.
Aylmore M.G.,Tenova Mining and Minerals Australia Pty Ltd. |
Staunton W.P.,Curtin University Australia
Hydrometallurgy | Year: 2014
The effect of some typical oxide and sulfide minerals, as well as activated carbon, on synthetic gold thiosulfate leach solutions was examined. The presences of pyrite and goethite in a synthetic ore slurry have a significant effect on the adsorption and stability of gold, silver, copper and polythionates in ammoniacal thiosulfate solutions. Adsorption of tetrathionate in particular leads to significant gold and silver losses. The adsorption of copper on mineral surfaces inhibited gold and silver losses, even in the presence of tetrathionate. However, goethite was found to strongly adsorb copper(II). It is concluded that gold extraction from natural ores is lower than that obtained with cyanide, partly as a result of sorption or precipitation reactions. Furthermore, the presence of silver in solution catalyses the precipitation of a mixed copper/silver/gold sulfide in ammoniacal thiosulfate solutions containing tetrathionate. © 2014 Elsevier B.V.
Tait R.J.,Australian National University |
Tait R.J.,Curtin University Australia |
Spijkerman R.,Parnassia Addiction Research Center |
Riper H.,VU University Amsterdam |
Riper H.,Luneburg University
Drug and Alcohol Dependence | Year: 2013
Background: Worldwide, cannabis is the most prevalently used illegal drug and creates demand for prevention and treatment services that cannot be fulfilled using conventional approaches. Computer and Internet-based interventions may have the potential to meet this need. Therefore, we systematically reviewed the literature and conducted a meta-analysis on the effectiveness of this approach in reducing the frequency of cannabis use. Methods: We systematically searched online databases (Medline, PubMed, PsychINFO, Embase) for eligible studies and conducted a meta-analysis. Studies had to use a randomized design, be delivered either via the Internet or computer and report separate outcomes for cannabis use. The principal outcome measure was the frequency of cannabis use. Results: Data were extracted from 10 studies and the meta-analysis involved 10 comparisons with 4125 participants. The overall effect size was small but significant, g= 0.16 (95% confidence interval (CI) 0.09-0.22, P<. 0.001) at post-treatment. Subgroup analyses did not reveal significant subgroup differences for key factors including type of analysis (intention-to-treat, completers only), type of control (active, waitlist), age group (11-16, 17+ years), gender composition (female only, mixed), type of intervention (prevention, 'treatment'), guided versus unguided programs, mode of delivery (Internet, computer), individual versus family dyad and venue (home, research setting). Also, no significant moderation effects were found for number of sessions and time to follow-up. Finally, there was no evidence of publication bias. Conclusions: Internet and computer interventions appear to be effective in reducing cannabis use in the short-term albeit based on data from few studies and across diverse samples. © 2013 Elsevier Ireland Ltd.
Terziovski M.,Curtin University Australia |
Guerrero J.-L.,Georgetown University
International Journal of Production Economics | Year: 2014
ISO 9000 quality system certification has been widely applied around the world, but with mixed success. A review of the literature revealed gaps in research in this area of quality/operations management, particularly in the empirical testing of the effects of ISO 9000 certification on innovation performance. This study examines the impact of ISO 9000 certification on product and process innovation performance of 220 Australian organizations. Our results show that ISO 9000 certification does not have a statistically significant relationship with product innovation performance measures such time-tomarket (TTM) of new products. ISO 9000 certification tends to drive out variance increasing activities, which in turn affects the organization's ability to innovate. Conversely, ISO 9000 certification has a positive and significant impact on process innovation performance measures such as restructuring and application of the internal customer concept. ISO 9000 certified firms are more likely to include restructuring, and to apply the internal customer concept throughout their organization to improve cooperation and to create flatter structures as part of their process innovation activities. The .ndings of this study have implication for managers and auditing bodies. Managers should exercise caution when choosing processes to certify, and auditing bodies should consider the paradox between product innovation and process innovation in the next revision of the ISO 9000 standard. © 2014 Elsevier B.V. All rights reserved.
Glasser L.,Curtin University Australia |
Jenkins H.D.B.,University of Warwick
Journal of Chemical and Engineering Data | Year: 2011
Thermodynamics, as both thermochemistry and thermophysics, is fundamental and central to the science of matter and, in particular, of condensed materials. While extensive data resources for thermodynamic quantities do exist, none of the experimental, simulation, or theoretical studies can keep pace with the rate of synthesis of new materials or provide reliable data for hypothesized materials. Correlation methods can fill this gap. We describe a range of recently developed correlation methods that rely on volume to predict thermodynamic quantities. In parallel with these, thermodynamic difference rules, which describe how properties of materials (say, of a group of solvates) may be inferred from corresponding properties of materials that neighbor them in composition, have recently been reviewed. © 2010 American Chemical Society.
Garcia-Sosa A.T.,University of Tartu |
Mancera R.L.,Curtin University Australia
Molecular Informatics | Year: 2010
The accurate calculation of the free energy of interaction of protein-water-ligand systems has an important role in molecular recognition and drug design that is often not fully considered. We report free energy thermodynamic integration calculations used to evaluate the effects of inclusion, neglect, and targeting and removal (i.e., systematic substitution by ligand functional groups) of an important, tightly bound, water molecule in the SH3 domain of Abl tyrosine kinase. The effects of this water molecule on the free energies of interaction of several Abl-SH3 domain-ligand systems reveal that there is an unfavourable free energy change associated with its removal into the bulk solvent. Only three substitutions by an additional functional group (out of methyl, ethyl, hydroxyl, amino, and amide groups) in the phenyl ring of a tyrosine in the peptide ligand resulted in a favourable change in the free energy of binding upon replacement of the ordered water molecule. This computational approach provides a direct route to the systematic and rigorous prediction of the thermodynamic influence of ordered, structural water molecules on ligand modification and optimization in drug design by calculating free energy changes in protein-water-ligand systems. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Bateman P.W.,Curtin University Australia |
Fleming P.A.,Murdoch University
Behavioral Ecology and Sociobiology | Year: 2014
Most studies examining escape behaviour have considered single approaches and single fleeing responses; few have considered how organisms' response is influenced by persistent pursuit. We explored fleeing behaviour of two grasshopper species to test whether they modified escape behaviour when approached repeatedly. Schistocerca alutacea did not increase flight initiation distance (FID) upon repeated approach but fled farther. Psinidia fenestralis increased its FID on the second approach but decreased its flight distance over successive escapes. Both species showed a bimodal pattern of flight direction, either flying directly away or flying perpendicular to the direction of the observer's approach. Neither species showed a significant pattern of flight direction or change in flight direction with successive escapes. Most (88 %) P. fenestralis initially landed on sand, but after repeated approaches an increasing proportion landed in grass and hid. Both species therefore changed escape behaviour with persistent pursuit but used different tactics, suiting their flight ability or camouflage, and optimised habitat use. Three grasshopper species have now been examined for responses to repeated approach by predators and all show different tactics supporting escape decision theory. Our results emphasise the variety of escape responses across species and how the dynamic nature of escape responses vary according to an animal's situation. Rather than single optimum escape options, each grasshopper species shows a range of responses, which vary with risk from persistent predators. Although grasshoppers provide an excellent model, it would be profitable to examine responses of a range of species according to levels of predation risk. © 2013 Springer-Verlag Berlin Heidelberg.
Raynes-Goldie K.,Curtin University Australia
First Monday | Year: 2010
This paper explores how 20-something Facebook users understand and navigate privacy concerns. Based on a year-long ethnographic study in Toronto, Canada, this paper looks at how - contrary to many mainstream accounts - younger users do indeed care about protecting and controlling their personal information. However, their concerns revolve around what I call social privacy, rather than the more conventional institutional privacy. This paper also examines the somewhat subversive practices which users engaged in to enhance their own social privacy, and in some cases, violate that of others. Finally, this paper examines some of the reasons that users may continue using the site, despite privacy concerns.
Xiang Y.,Beihang University |
Lu S.,Beihang University |
Jiang S.P.,Curtin University Australia
Chemical Society Reviews | Year: 2012
As one of the most effective synthesis tools, layer-by-layer (LbL) self-assembly technology can provide a strong non-covalent integration and accurate assembly between homo- or hetero-phase compounds or oppositely charged polyelectrolytes, resulting in highly-ordered nanoscale structures or patterns with excellent functionalities and activities. It has been widely used in the developments of novel materials and nanostructures or patterns from nanotechnologies to medical fields. However, the application of LbL self-assembly in the development of highly efficient electrocatalysts, specific functionalized membranes for proton exchange membrane fuel cells (PEMFCs) and electrode materials for supercapacitors is a relatively new phenomenon. In this review, the application of LbL self-assembly in the development and synthesis of key materials of PEMFCs including polyelectrolyte multilayered proton-exchange membranes, methanol-blocking Nafion membranes, highly uniform and efficient Pt-based electrocatalysts, self-assembled polyelectrolyte functionalized carbon nanotubes (CNTs) and graphenes will be reviewed. The application of LbL self-assembly for the development of multilayer nanostructured materials for use in electrochemical supercapacitors will also be reviewed and discussed (250 references). © 2012 The Royal Society of Chemistry.
Goh Y.M.,Curtin University Australia |
Chua D.K.H.,National University of Singapore
Journal of Construction Engineering and Management | Year: 2010
Risk assessment, consisting of hazard identification and risk analysis, is an important process that can prevent costly incidents. However, due to operational pressures and lack of construction experience, risk assessments are frequently poorly conducted. In order to improve the quality of risk assessments in the construction industry, it is important to explore the use of artificial intelligence methods to ensure that the process is efficient and at the same time thorough. This paper describes the adaptation process of a case-based reasoning (CBR) approach for construction safety hazard identification. The CBR approach aims to utilize past knowledge in the form of past hazard identification and incident cases to improve the efficiency and quality of new hazard identification. The overall approach and retrieval mechanism are described in earlier papers. This paper is focused on the adaptation process for hazard identification. Using the proposed CBR approach, for a new work scenario (the input case), a most relevant hazard identification tree and a set of incident cases will be retrieved to facilitate hazard identification. However, not all information contained in these cases are relevant. Thus, less relevant information has to be pruned off and all the retrieved information has to be integrated into a hazard identification tree. The proposed adaptation is conducted in three steps: (1) pruning of the retrieved hazard identification tree; (2) pruning of the incident cases; and (3) insertion of incident cases into the hazard identification tree. The adaptation process is based on the calculation of similarity scores of indexes. A case study based on actual hazard identifications and incident cases is used to validate the feasibility of the proposed adaptation techniques. © 2010 ASCE.
Schmid R.,University of Melbourne |
Ntogramatzidis L.,Curtin University Australia
Automatica | Year: 2010
We consider the use of linear multivariable feedback control to achieve a nonovershooting step response. A method is given for designing a linear time invariant state feedback controller to asymptotically track a constant step reference with zero overshoot and arbitrarily small rise time, under some mild assumptions. We present a unified design method that can be applied to continuous and discrete time systems, square and non-square systems, minimum and nonminimum phase systems, and also strictly proper and nonstrictly proper systems. © 2009 Elsevier Ltd. All rights reserved.
Iglauer S.,Curtin University Australia |
Paluszny A.,Imperial College London |
Blunt M.J.,Imperial College London
Fuel | Year: 2013
We imaged sandstone cores at residual gas saturation (Sgr) with synchrotron radiation at a nominal resolution of (9 μm)3. We studied two three-phase flooding sequences: (1) gas injection into a core containing oil and initial water followed by a waterflood (gw process); (2) gas injection into a waterflooded core followed by another waterflood (wgw process). In the gw flood we measured a significantly higher Sgr (=20.6%; Sgr in the wgw flood was 5.3%) and a significantly lower residual oil saturation (Sor; Sor in the gw flood was 21.6% and S or in the wgw flood was 29.3%). We also studied the size distribution of individual trapped clusters in the pore space. We found an approximately power-law distribution N ∝ s-τ with an exponent τ = 2.02-2.03 for the residual oil clusters and τ = 2.04 for the gas clusters in the gw flood. τ (=2.32) estimated for the gas clusters in the wgw process was significantly different. Furthermore, we calculated the surface area A-volume V relationships for the clusters. Again an approximate power-law relationship was observed, A ∝ Vp with p ≈ 0.75. Moreover, in the gw flood sequence we identified oil layers sandwiched between the gas and water phases; we did not identify such oil layers in the wgw flood. These results have several important implications for oil recovery, carbon geo-sequestration and contaminant transport: (a) significantly more oil can be produced and much more gas can be stored using a gw flood; (b) cluster size distributions for residual oil or gas clusters in three-phase flow are similar to those observed in analogue two-phase flow; (c) there is a large cluster surface area available for dissolution of the residual phase into an aqueous phase; however, this surface area is significantly smaller than predicted by percolation theory (p ≈ 1), which implies that CO2 dissolution trapping and contamination of aquifers by hazardous organic solvents is slower than expected because of reduced interfacial contact areas. © 2012 Elsevier Ltd. All rights reserved.
Christou A.,Curtin University Australia
BMC public health | Year: 2010
BACKGROUND: Despite a lower incidence of bowel cancer overall, Indigenous Australians are more likely to be diagnosed at an advanced stage when prognosis is poor. Bowel cancer screening is an effective means of reducing incidence and mortality from bowel cancer through early identification and prompt treatment. In 2006, Australia began rolling out a population-based National Bowel Cancer Screening Program (NBCSP) using the Faecal Occult Blood Test. Initial evaluation of the program revealed substantial disparities in bowel cancer screening uptake with Indigenous Australians significantly less likely to participate in screening than the non-Indigenous population.This paper critically reviews characteristics of the program which may contribute to the discrepancy in screening uptake, and includes an analysis of organisational, structural, and socio-cultural barriers that play a part in the poorer participation of Indigenous and other disadvantaged and minority groups. METHODS: A search was undertaken of peer-reviewed journal articles, government reports, and other grey literature using electronic databases and citation snowballing. Articles were critically evaluated for relevance to themes that addressed the research questions. RESULTS: The NBCSP is not reaching many Indigenous Australians in the target group, with factors contributing to sub-optimal participation including how participants are selected, the way the screening kit is distributed, the nature of the test and comprehensiveness of its contents, cultural perceptions of cancer and prevailing low levels of knowledge and awareness of bowel cancer and the importance of screening. CONCLUSIONS: Our findings suggest that the population-based approach to implementing bowel cancer screening to the Australian population unintentionally excludes vulnerable minorities, particularly Indigenous and other culturally and linguistically diverse groups. This potentially contributes to exacerbating the already widening disparities in cancer outcomes that exist among Indigenous Australians. Modifications to the program are recommended to facilitate access and participation by Indigenous and other minority populations. Further research is also needed to understand the needs and social and cultural sensitivities of these groups around cancer screening and inform alternative approaches to bowel cancer screening.
Godfrey E.,University of Auckland |
Parker L.,Curtin University Australia
Journal of Engineering Education | Year: 2010
BACKGROUND: Calls for culture change as key to systemic reform in engineering education implicitly assume the existence of common elements of a distinctive culture. The landscape for engineering education studies that invoke the concept of culture is complex and multi-faceted, yet still ill-defined and incomplete. PURPOSE (HYPOTHESIS): The aim of this study is to develop a conceptual framework of cultural dimensions that has the potential to guide the understanding of culture in the context of engineering education to demonstrate "where we are" and "how to get where we want to go." DESIGN/METHOD: Ethnographic methods within an overarching interpretivist research paradigm were used to investigate the culture of engineering education as manifested in one institution. Adapting Schein's cultural framework, the data were collected and analyzed to distil from observable behaviors and practices the essence of the culture in the form of tacitly known cultural norms, shared assumptions, and understandings that underpinned the lived experience of staff and students. RESULTS: The findings are discussed within six cultural dimensions which emerged from the data as: An Engineering Way of Thinking, An Engineering Way of Doing, Being an Engineer, Acceptance of Difference, Relationships and Relationship to the Environment. CONCLUSIONS: The detailed findings from this study, combined with evidence from other studies, support the view that the proposed six dimensions have the potential to be transferred to other institutions as a practical tool for evaluating and positioning the culture of engineering education.
Oliver R.,Curtin University Australia
New Phytologist | Year: 2012
Genome sequencing has been carried out on a small selection of major fungal ascomycete pathogens. These studies show that simple models whereby pathogens evolved from phylogenetically related saprobes by the acquisition or modification of a small number of key genes cannot be sustained.The genomes show that pathogens cannot be divided into three clearly delineated classes (biotrophs, hemibiotrophs and necrotrophs) but rather into a complex matrix of categories each with subtly different properties. It is clear that the evolution of pathogenicity is ancient, rapid and ongoing. Fungal pathogens have undergone substantial genomic rearrangements that can be appropriately described as 'genomic tillage'. Genomic tillage underpins the evolution and expression of large families of genes - known as effectors - that manipulate and exploit metabolic and defence processes of plants so as to allow the proliferation of pathogens. © 2012 The Author. New Phytologist © 2012 New Phytologist Trust.
Zhang G.,Tianjin University |
Liu W.,Curtin University Australia
IEEE Transactions on Automatic Control | Year: 2011
The problem of impulsive mode elimination for descriptor systems via a structured output proportional and derivative (P-D) feedback is investigated in this technical note. The motivation of solving this problem arises from an observation that the impulse behavior for some descriptor systems can not be eliminated completely by a parameterized output P-D feedback, but it can be removed by a structured P-D feedback elegantly designed. In order to explain this phenomenon explicitly, a concept of the structured P-D feedback is first introduced, then an explicit necessary and sufficient condition is constructively derived for the closed loop systems to be regular and impulse-free by the structured P-D feedback. The main result is represented in terms of the original system parameters instead of decomposed subsystem parameters. Finally, an example is provided to illustrate the effectiveness of the proposed result. © 2006 IEEE.
Dam H.H.,Curtin University Australia
IEEE Transactions on Signal Processing | Year: 2011
This correspondence investigates the least squares and minimax design problems for allpass variable fractional delay (VFD) filters. A two stage optimization approach is proposed to solve the resulting minimax optimization problem. This approach includes a combination of a one-dimensional global search method and an adaptive scheme to refine the discretization points. In addition, the paper investigates the design of allpass VFD filters which minimizes the weighted integral squared error subject to constraints on peak error deviation from the desired response. By using approximations, the design problem can be formulated as a quadratic optimization problem. Design examples show that a tradeoff between the weighted integral squared error and the peak error deviation can be achieved. In addition, the integral squared error can be reduced significantly from the minimax solution while maintaining approximately the same peak error deviation. Similarly, the peak error deviation can be significantly reduced from the least squares solution while maintaining approximately the same integral squared error. © 2011 IEEE.
Rong Y.,Curtin University Australia
IEEE Communications Letters | Year: 2011
In this letter, we study two-way nonregenerative multiple-input multiple-output (MIMO) relay communications with multiple relay nodes. An iterative algorithm is developed to jointly optimize the source, relay, and receive matrices such that the two-way sum mean-squared error (MSE) of the signal waveform estimation is minimized. Numerical examples demonstrate a better performance of the proposed algorithm compared with existing algorithms for two-way MIMO multi-relay networks. © 2006 IEEE.
Glasser L.,Curtin University Australia
Journal of Chemical Thermodynamics | Year: 2014
Lanthanoid (or lanthanide) garnets are ionic solids of technological importance in their use in electronic materials. They are also of interest in respect of their systematic relationships and as geochemical tracers. As a consequence, there is considerable published thermodynamic information for these garnets. Based principally on the computational results of Moretti and Ottonello (1998) , we here examine the thermodynamic information for consistencies and anomalies among the ferri-, alumino-, and gallo-garnets using relations between thermodynamic properties that we have established over recent years. The principal properties of interest are formula volume, heat capacity, entropy, and formation enthalpy (from which the Gibbs free energy may be obtained), and isothermal compressibility. We also establish additive single-ion values for trivalent lanthanide cations which may be applied in estimating properties for related materials. Since the results of the work of Moretti and Ottonello are based upon consistent computational analyses, we should expect generally smooth relations. These are, indeed, found for various of the properties (except for the europium garnets), with some uncertainty in the absolute entropies, and anomalies in the formation enthalpies of europium and ytterbium/lutetium garnets. The results of some more recent experimental work are included in our analyses. Values for the (unknown) promethium garnets are estimated by averaging the properties of the neighbouring neodymium and samarium garnets. © 2014 Elsevier Ltd. All rights reserved.
Casassa S.,University of Turin |
Demichelis R.,Curtin University Australia
Journal of Physical Chemistry C | Year: 2012
The relative energy of aluminum mono- (boehmite and diaspore) and trihydroxides (gibbsite, bayerite, doyleite, and nordstrandite) was investigated with a periodic local Møller-Plesset second-order perturbative approach, with the aim of providing a reliable trend of stability on the basis of a proper description of both the long-range Coulomb interactions and the short-range correlation effects. These components, disregarded in previous studies based on the density functional theory, turn out to be important for these kinds of systems, where hydrogen bonds and van der Waals forces play a fundamental role in stabilizing the structure. The results are in good agreement with the available experimental evidence. The reasons for the monohydroxides energy difference were investigated, with diaspore showing an electronic structure for oxygen atoms more favorable than that for boehmite. The problem of the nordstrandite structure was reexamined because of the presence of a second minimum energy structure on the energy surface. Both of them are higher in energy than those of the other trihydroxide polymorphs, and the relative stability of one of these structures with respect to gibbsite is in agreement with recent experimental investigations. © 2012 American Chemical Society.
Brown A.,Curtin University Australia
Renewable and Sustainable Energy Reviews | Year: 2016
Some consideration has been given to regulatory and institutional reforms to facilitate sustainable development in electricity usage in Papua New Guinea but little attention has been paid to bringing about full compliance of financial reporting expectations of the country's main energy utility. Examining documentary evidence of the audit reports of the Auditor General's Office of Papua New Guinea, this study considers the financial reporting compliance of PNG Power for the period 2007-2013, and the means by which compliant reporting may be improved. The results of the study reveal that the financial statements of PNG Power are late and receive disclaimers of opinion from the Auditor General's Office, which suggest that PNG Power's stakeholders are not receiving accurate and reliable financial information to make informed decisions about sustainable development of electricity usage and planning in Papua New Guinea. The study reveals that it would take little resources to improve PNG Power's reporting, which in turn could enhance national energy policy decision-making and energy utility accountability. © 2016 Published by Elsevier Ltd.
Arnott D.,Monash University |
Pervan G.,Curtin University Australia
Journal of the Association of Information Systems | Year: 2012
Design science has been an important strategy in decision support systems (DSS) research since the field's inception in the early 1970s. Recent reviews of DSS research have indicated a need to improve its quality and relevance. DSS design-science research has an important role in this improvement because design-science research can engage industry and the profession in intellectually important projects. The Hevner, March, Park, and Ram's (HMPR) guidelines for the conduct and assessment of information systems design-science research, published in MIS Quarterly in 2004, provides a vehicle for assessing DSS design-science research. This paper presents research that used bibliometric content analysis to apply the HMPR guidelines to a representative sample of 362 DSS design-science research papers in 14 journals. The analysis highlights major issues in DSS research that need attention: research design, evaluation, relevance, strategic focus, and theorizing.
Ebert J.R.,University of Western Australia |
Smith A.,Curtin University Australia |
Wood D.J.,University of Western Australia |
Ackland T.R.,University of Western Australia
American Journal of Sports Medicine | Year: 2013
Background: Patient-reported outcome (PRO) instruments are employed to assess outcomes after matrix-induced autologous chondrocyte implantation (MACI), although the PRO most responsive to change after surgery remains unknown. Purpose: To compare the responsiveness of 4 commonly used PRO instruments at 5 years after MACI. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: The Knee Injury and Osteoarthritis Outcome Score (KOOS), the Lysholm score, the Tegner activity scale, and the 36- item Short Form Health Survey (SF-36) were administered to 104 patients before and at 5 years after MACI knee surgery. The Selfadministered Patient Satisfaction Scale was employed at 5 years to investigate each patient's overall level of satisfaction as well as satisfaction with relieving pain and improving the ability to perform daily activities, partake in recreational activities, and participate in sport. The effect size (ES) and standardized response mean (SRM) were used to compare PRO responsiveness. A receiver operating characteristic (ROC) curve analysis was performed to evaluate the extent to which PRO changes were associated with satisfaction. The minimal clinically important difference (MCID) according to the criterion of patient satisfaction was identified as the PRO instrument change score maximizing classification accuracy. Results: The most responsive PRO measures were the KOOS sport/recreation (ES, 1.63; SRM, 1.43) and quality of life (QOL) (ES, 1.37; SRM, 1.18) subscales. The least responsive were the SF-36 mental component summary (MCS) (ES, 0.38; SRM, 0.40) and the Tegner activity scale (ES, 0.91; SRM, 0.59). Of the 104 patients, 54 (51.9%) reported being "very satisfied," 38 (36.5%) "somewhat satisfied," 8 (7.7%) "somewhat dissatisfied," and 4 (3.9%) "very dissatisfied." A ROC curve analysis was performed using "very satisfied" as the responder criterion. The strongest association was between the change in KOOS sport/recreation with satisfaction in improving the ability to perform recreational activities (area under the curve, 0.756; 95% confidence interval, 0.663-0.849), and the change score maximizing prediction accuracy (MCID) was 40 (sensitivity, 69%; specificity, 76%). Conclusion: The KOOS sport/recreation and QOL subscales were the most responsive PRO measures and were most predictive of satisfaction. This information will provide a guide as to the improvements required in pertinent PRO measures to produce a satisfied patient, while allowing researchers to better structure trials in these patients using the most relevant PRO instruments. © 2013 The Author(s).
Merrick H.,Curtin University Australia
First Monday | Year: 2012
The notion of 'simple living' and the documenting of more sustainable lifestyles is an increasingly familiar topic of online writing. This paper presents a case study of two online forums focused on simple living, Aussies Living Simply and the Earth Garden Path. Site members were surveyed to examine the impact of the sites on their practice and understandings of sustainability. The study asks how such online communities might support the development of civic and individual action around sustainability, or "green citizenship". © 2012, First Monday © 2012, Helen Merrick.
Phan C.M.,Curtin University Australia
Journal of Physical Chemistry Letters | Year: 2014
Directional and controllable transportation of microdroplets is critical for emerging micro- and nanotechnology, in which the conventional mechanical energy generation is not applicable. This Letter shows that an aqueous microdroplet can be charged for controlled motion in electrostatic potential, which was created by differentiating pH, between two oil/water interfaces. The directional motion of the droplet, <100 μm in diameter, was obtained with a constant velocity of ∼1 mm/s. The force analysis showed that the droplet surface was charged and recharged oppositely by ion transfer through interfacial layers, without significant mass transfer. The charging and recharging cycles were recorded continuously with a single droplet over 100 times. The energy for motion was generated from pH neutralization, which is the simplest aqueous reaction. This is the first time that the phenomenon is reported. The phenomenon can be employed as an efficient and robust method to convert chemical to mechanical energy for miniaturized devices and microprocesses. © 2014 American Chemical Society.
Shafiee S.,University of Queensland |
Topal E.,Curtin University Australia
Applied Energy | Year: 2010
This paper reviews a long-term trend of worldwide fossil fuel prices in the future by introducing a new method to forecast oil, natural gas and coal prices. The first section of this study analyses the global fossil fuel market and the historical trend of real and nominal fossil fuel prices from 1950 to 2008. Historical fossil fuel price analysis shows that coal prices are decreasing, while natural gas prices are increasing. The second section reviews previously available price modelling techniques and proposes a new comprehensive version of the long-term trend reverting jump and dip diffusion model. The third section uses the new model to forecast fossil fuel prices in nominal and real terms from 2009 to 2018. The new model follows the extrapolation of the historical sinusoidal trend of nominal and real fossil fuel prices. The historical trends show an increase in nominal/real oil and natural gas prices plus nominal coal prices, as well as a decrease in real coal prices. Furthermore, the new model forecasts that oil, natural gas and coal will stay in jump for the next couple of years and after that they will revert back to the long-term trend until 2018. © 2009 Elsevier Ltd. All rights reserved.
Whiteside J.H.,UK National Oceanography Center |
Grice K.,Curtin University Australia
Annual Review of Earth and Planetary Sciences | Year: 2016
The history of life on Earth is punctuated by a series of mass extinction episodes that vary widely in their magnitude, duration, and cause. Biomarkers are a powerful tool for the reconstruction of historical environmental conditions and can therefore provide insights into the cause and responses to ancient extinction events. In examining the five largest mass extinctions in the geological record, investigators have used biomarkers to elucidate key processes such as eutrophy, euxinia, ocean acidification, changes in hydrological balance, and changes in atmospheric CO2. By using these molecular fossils to understand how Earth and its ecosystems have responded to unusual environmental activity during these extinctions, models can be made to predict how Earth will respond to future changes in its climate. Copyright © 2016 by Annual Reviews. All rights reserved.
Do K.D.,Curtin University Australia
Ocean Engineering | Year: 2015
Although environmental loads induced by waves, wind, and ocean currents on ocean vehicles are naturally stochastic, all existing works on controlling these vehicles treat the loads as deterministic. This treatment deteriorates the control performance or even results in an unstable closed loop system in a practical implementation. This paper presents a method to design controllers that force a fully actuated ocean vehicle under stochastic environmental loads to track a reference trajectory in three dimensional space. The control design is based on several recent results developed for stability and control of stochastic systems, and backstepping and Lyapunov's direct methods. The modified Rodrigues parameters are used for the attitude representation of the vehicle to reduce singularities in comparison with the use of Euler-angles and Rodrigues parameters. Simulations on an omni-directional intelligent navigator illustrate the results. © 2015 Elsevier Ltd.All rights reserved.
McKenzie F.H.,Curtin University Australia
Rangeland Journal | Year: 2011
Remote Australia constitutes ∼75% of the continent and is a dry, often harsh environment in which to live; consequently less than 3% of Australia's population reside there but it is also where a substantial proportion of Australia's export wealth is derived. It is therefore important that attention is paid to ensuring that remote locations in Australia are liveable and that innovative strategies are pursued to attract and retain a productive workforce in these places. Attracting and retaining skilled and professional staff is a problem not limited to remote, or even rural and regional locations in Australia. There is strong evidence to suggest that it is increasingly a global problem and organisations throughout the world are seeking innovative strategies to attract and develop new talent and developing other strategies to retain that talent. This paper examines population and labour mobility trends in remote Australia and the issues that have been influential on rates of staff attraction and retention, most particularly adequate housing, services and infrastructure. The second half of the paper examines a variety of recommendations and strategies developed by the public and private sectors to more effectively attract and retain skilled and professional staff to remote locations. This paper does not claim to be a rigorous analysis of all remote areas of Australia nor a comprehensive study of attraction and retention strategies. Rather, it aims to highlight the complexity, depth and interconnectedness of the issues for communities, public and private sectors and how they apply in remote locations in Australia. © 2011 Australian Rangeland Society.
Silvester D.S.,Curtin University Australia
Analyst | Year: 2011
Ionic Liquids are salts that are liquid at (or just above) room temperature. They possess several advantageous properties (e.g. high intrinsic conductivity, wide electrochemical windows, low volatility, high thermal stability and good solvating ability), which make them ideal as non-volatile electrolytes in electrochemical sensors. This mini-review article describes the recent uses of ionic liquids in electrochemical sensing applications (covering the last 3 years) in the context of voltammetric sensing at solid/liquid, liquid/liquid interfaces and carbon paste electrodes, as well as their use in gas sensing, ion-selective electrodes, and for detecting biological molecules, explosives and chemical warfare agents. A comment on the future direction and challenges in this field is also presented. © 2011 The Royal Society of Chemistry.
De Laeter J.,Curtin University Australia
Mass Spectrometry Reviews | Year: 2011
The nucleosynthetic characteristics of U and Pb, together with the interconnectivity between these elements by two radioactive decay chains, are the foundation on which the U/Pb system was able to make a unique contribution to isotope science. The Rosetta Stone is an ancient Egyptian tablet that enabled previously indecipherable hieroglyphics to be translated. In a similar manner, the isotopic investigation of the U/Pb system, by a variety of mass spectrometric instrumentation, has led to our knowledge of the age of the Earth and contributed to thermochronology. In a similar manner, climate change information has been garnered by utilizing the U-Disequilibrium Series to measure the ages of marine archives. The impact of Pb in the environment has been demonstrated in human health, particularly at the peak of leaded petrol consumption in motor vehicles in the 1970s. Variations in the isotopic composition of lead in samples enable the source of the lead to be "fingerprinted" so as to trace the history of the Pb in ice cores and aerosols. The discovery of nuclear fission of 235U led to the development of nuclear reactors and the isotopic investigation of the Oklo natural reactors. The mass spectrometer is the modern Rosetta Stone of isotope science, which has enabled the isotopic hieroglyphics of the U/Pb system to be investigated to reveal new horizons in our understanding of nature, and to address a number of societal and environmental problems. © 2010 Wiley Periodicals, Inc.
Dolzhenko A.V.,Curtin University Australia
Heterocycles | Year: 2011
The present review summarizes information on the synthetic approaches to compounds with pyrimido[1,2-a][1,3,5]triazines, 1,3,5-triazino[2,1-b] quinazolines (benzofused pyrimido[1,2-a][1,3,5]triazines), and other polyfused heterocyclic systems bearing these scaffolds. Data concerning potential applications of the pyrimido[1,2-a][1,3,5]triazines, particularly as biologically active agents, are also discussed. © The Japan Institute of Heterocyclic Chemistry.
MacQuart J.-P.,Curtin University Australia
Astrophysical Journal | Year: 2011
We relate the underlying properties of a population of fast radio-emitting transient events to its expected detection rate in a survey of finite sensitivity. The distribution of the distances of the detected events is determined in terms of the population luminosity distribution and survey parameters, for both extragalactic and Galactic populations. The detection rate as a function of Galactic position is examined to identify regions that optimize survey efficiency in a survey whose field of view is limited. The impact of temporal smearing caused by scattering in the interstellar medium has a large and direction-dependent bearing on the detection of impulsive signals, and we present a model for the effects of scattering on the detection rate. We show that the detection rate scales as ΩS -3/2 + δ 0, where Ω is the field of view, S 0 is the minimum detectable flux density, and 0 < δ ≤ 3/2 for a survey of Galactic transients in which interstellar scattering or the finite volume of the Galaxy is important. We derive formal conditions on the optimal survey strategy to adopt under different circumstances for fast transient surveys on next generation large-element, wide-field arrays, such as ASKAP, LOFAR, the MWA, and the SKA, and show how interstellar scattering and the finite spatial extent of a Galactic population modify the choice of optimal strategy. © 2011. The American Astronomical Society. All rights reserved.
Rong Y.,Curtin University Australia |
Xiang Y.,Deakin University
IEEE Transactions on Wireless Communications | Year: 2011
In this letter, we address multiuser multi-hop multiple-input multiple-output (MIMO) relay communication systems with correlated MIMO fading channels. In particular, we consider the practical scenario where the channel fading is fast and thus the instantaneous channel state information (CSI) is only available at the destination node, but unknown at all users and all relay nodes. We derive the structure of the optimal user precoding matrices and relay amplifying matrices that maximizes the users-destination ergodic sum mutual information. Compared with existing works, our results are more general, since we address multiuser scenarios, consider MIMO relays with a finite dimension, and take into account the noise vector at each relay node. © 2006 IEEE.
Ntogramatzidis L.,Curtin University Australia |
Ferrante A.,University of Padua
IET Control Theory and Applications | Year: 2011
In this study, the authors introduce a range of techniques for the exact design of PID controllers for feedback control problems involving requirements on the steady-state performance and standard frequency-domain specifications on the stability margins and crossover frequencies. These techniques hinge on a set of simple closed-form formulae for the explicit computation of the parameters of the controller in finite terms as functions of the specifications, and therefore they eliminate the need for graphical, heuristic or trial-and-error procedures. The relevance of this approach is (i) theoretical, since a closed-form solution is provided for the design of PID-type controllers with standard frequency-domain specifications; (ii) computational, since the techniques presented here are readily implementable as software routines, for example, using MATLAB®; (iii) educational, because the synthesis of the controller reduces to a simple exercise on complex numbers that can be solved with pen, paper and a scientific calculator. These techniques also appear to be very convenient within the context of adaptive control and self-tuning strategies, where the controller parameters have to be calculated online. Furthermore, they can be easily combined with graphical and first/second-order plant approximation methods in the cases where the model of the system to be controlled is not known. © 2011 The Institution of Engineering and Technology.
Evans K.-A.,Curtin University Australia |
Tomkins A.-G.,Monash University
Earth and Planetary Science Letters | Year: 2011
A number of lines of evidence point to a causal link between oxidised slab-derived fluids, oxidised sub-arc mantle, and the formation of economic concentrations of metals such as Cu and Au that require oxidised magmas. However, trace element evidence from some trace element and isotope data suggests that sub-arc mantle is no more oxidised than mantle elsewhere.A simple analytical model is applied to constrain the evolution of sub-arc mantle oxidation state as a function of redox-budget fluxes from the subducting slab. Influential variables include the solubility of Fe3+ and SO4 2- in slab-derived fluids, the geometry of the infiltration of slab-derived fluids in sub-arc mantle, the coupling between slab-derived and arc-output redox budgets, and the concentration of redox-buffering elements such as Fe and S in the sub-arc mantle.Plausible Archean and Proterozoic redox budget fluxes would not have created oxidised sub-arc mantle without input from ferric iron or sulphate dissolved in non-aqueous fluids such as silicate melts. Aqueous-borne Phanerozoic redox budget fluxes, on the other hand, which are dominated by the sulphate component, could have increased sub-arc fO2 by up to three log10 units. The results are generally consistent with the proposed elevated fO2 for sub-arc mantle, but no resolution was found for the apparent contradiction between high proposed fO2 values derived from iron-based oxybarometry and the lower values inferred from trace element and isotope evidence.Increases in sub-arc mantle fO2 are favoured by focussed fluid infiltration and magma generation, weak coupling between slab and arc-output redox budgets, and restricted redox-buffering in the sub-arc mantle. Fertile arc segments for ore deposits associated with oxidised magmas require fluid chemistry and pressure-temperature gradients that enhance Fe3+ and SO4 2- solubility in aqueous and silica-rich fluids, tectonic stress regimes that favour focussed transfer of components into the sub-arc mantle, and a relatively weak redox buffer for the sub-arc mantle. The paucity of Cu and Au deposits associated with oxidised magmas in Precambrian rocks may be explained as a consequence of a lack of subducted oxidised material, rather than simply as a consequence of preservation potential. Additionally, the reduced nature of subducted material in the Precambrian may have caused S and metal enrichment in the sub-arc mantle. © 2011 Elsevier B.V.
Raimondo T.,University of Adelaide |
Clark C.,Curtin University Australia |
Hand M.,University of Adelaide |
Faure K.,Institute of Geological & Nuclear Sciences
Journal of Metamorphic Geology | Year: 2011
The Reynolds-Anmatjira Ranges, central Australia, form part of a high-grade basement terrane dissected by intensely metasomatized transpressional shear zones active during the Ordovician-Carboniferous Alice Springs Orogeny. Unlike typical retrograde structures associated with discrete fluid flow, the mid-crustal setting and intracontinental nature of these shear systems present significant problems for the source and ingress mechanism of the fluid involved in their rehydration. To address these issues, we describe two detailed traverses across deformed and metasomatized basement rocks in this region, and interrogate their record of fluid-rock interaction from various perspectives. Both traverses combine structural and petrological observations with Zr-in-rutile and Ti-in-quartz thermobarometry, oxygen and hydrogen stable isotope analysis, and major, trace and rare earth element mobility trends. Each technique is critically evaluated for its utility in this study and its more widespread applicability to alternative field areas, providing a strategic framework for the general investigation of fluid-affected shear zones. Ultimately, the integrated data sets specify pressure-temperature conditions of ~530°C and 4-5kbar, implying average apparent thermal gradients of 29-36°Ckm-1 and depths of 14-18km. Other characteristic features to emerge include strongly variable element mobilities and pronounced isotopic depletion fronts consistent with the alteration effects of an externally derived, non-equilibrium fluid. This is confirmed by calculated fluid compositions indicative of contributions from a fluid of meteoric origin, with estimated δ18O and δD values as low as 2.3‰ and -59.8‰, respectively. We propose that these surficial fluid signatures are imposed on the mid-crust by the prograde burial and dehydration of hydrothermally altered fault panels produced during pre-orogenic basin formation. Progressive fluid release with continued subsidence then leads to the accumulation of increasing fluid volumes in the vicinity of the brittle-ductile transition, promoting extensive hydration, metasomatism and reaction softening at the locus of stress transmission from plate-boundary sources. The sustained injection of externally derived fluids into refractory crustal material may thus stimulate a critical reduction in the long-term strength of the lithosphere, providing strong impetus for the initiation and advancement of intracontinental orogenesis. © 2011 Blackwell Publishing Ltd.
Wilde S.A.,Curtin University Australia
Tectonophysics | Year: 2015
The Central Asian Orogenic Belt (CAOB) evolved through complex closure of the Paleo-Asian Ocean from the Neoproterozoic to the late Phanerozoic. This caused the Chinese cratons to collide with Eurasia and led to the formation of the world's largest Phanerozoic orogenic belt. Ocean closure commenced in the west and was completed in the east near Changchun. Closure of the Paleo-Asian Ocean in NE China was along the Solonker-Xar Moron-Changchun-Yanji suture and this was likely completed in the Late Permian, although associated activity continued into the Triassic. There was an overlap in the latest Permian-Early Triassic between terminal activity associated with Paleo-Asian Ocean closure and the onset of tectonism associated with subduction of the Paleo-Pacific plate. This switch in geodynamic setting occurred at ~. 260-250. Ma, and is reflected by a relaxing of north-south directed compression and the onset of east-west directed processes related to Paleo-Pacific subduction. By the Early Jurassic, events associated with the westward advance of the Paleo-Pacific plate dominated, leading to extensive development of I-type granites as far inland as the Great Xing'an Range. From ~. 140. Ma, the Paleo-Pacific plate retreated eastward, resulting in an extensional setting in the Early Cretaceous, the effects of which were enhanced by regional thinning of the lithosphere, commonly attributed to delamination. Throughout this period, the eastern Asian margin was tectonically complex. The north-south oriented Jiamusi-Khanka(-Bureya) block was rifted away from the eastern margin of the CAOB in the Late Triassic, but was then re-united in the Jurassic by westward-advancing subduction that affected both the western and eastern margins of the block. Accretionary complexes continued to evolve in the Cretaceous along the whole eastern margin of Asia, with final accretion of the Nadanhada Terrane (part of the Sikhote-Alin accretionary terrane) with the CAOB at ~. 130. Ma, followed by the emplacement of S-type granites. © 2015 Elsevier B.V.
Newsholme P.,Curtin University Australia |
De Bittencourt P.I.H.,Federal University of Rio Grande do Sul |
De Bittencourt P.I.H.,National Institute of Hormones and Womens Health
Current Opinion in Clinical Nutrition and Metabolic Care | Year: 2014
Obesity is a chronic inflammatory disease in which the physiological resolution of inflammation is attenuated, leading to low-grade inflammation throughout the body. However, the heat shock response, which is a key component of the physiological response to resolve inflammation, is seriously hampered in adipose tissue and other metabolic organs (e.g. skeletal muscle, liver, pancreatic β-cells) in metabolic diseases. In this review, we hypothesize that adipocyte metabolic stress triggers the onset of fat cell senescence, and companion senescence-Associated secretory phenotype (SASP), and that such a scenario is responsible for attenuating the resolution of inflammation. RECENT FINDINGS: We shall discuss the role of the heat shock response in the context of the resolution of inflammation and the relevance of heat shock response blockade in chronic inflammatory diseases. Sirtuin-1 is responsible for the induction of heat shock transcription factor-1 mRNA expression and for the stabilization of heat shock transcription factor-1 in a high-profile activity state. However, adipose tissue-emanated SASP depress sirtuin-1 expression, leading adipocytes to a perpetual state of unresolved inflammation, due to a dampening of the heat shock response. SUMMARY: The advance of inflammasome-mediated SASP from adipose to other tissues promotes cellular senescence in many other cells of the organism, aggravating obesity-dependent chronic inflammation. Inducers of heat shock response (e.g. heat shock itself, physical exercise and calorie restriction) may efficiently interrupt this vicious cycle and are envisaged as the best and also the most economical treatment for obesity-related chronic diseases.Copyright © Lippincott Williams &Wilkins.
Jiang S.P.,Curtin University Australia |
Tang H.,Wuhan University of Technology
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2012
Layer-by-layer (LbL) self-assembly of polyelectrolyte bilayers on the methanol permeability and proton conductivity of Nafion membranes is investigated using polycations PDDA (poly(diallyldimethylammonium chloride)) and PAH (poly(allylamine hydrochloride)) and polyanions PAMP (poly(2-acrylamido-2-methyl-1-propanesulfonic acid)), PAZO (poly(1-(4-(3-carboxy-4-hydroxyphenylazo) benzene sulfonamido)-1,2-ethanediyl, sodium salt)), PSS (poly(sodium styrene sulfonate)) and PAA (poly(acrylic acid)). The formation of polyelectrolyte multilayers on Nafion membranes is confirmed by AFM and UV-visible spectroscopy. The lowest methanol permeability is observed on the self-assembled PDDA-PAA and PAH-PAA bilayers with the exponential growth process. The observed exponential growth process of polyelectrolyte multilayers with PAA polyanion is most likely related to small monomeric block of PAA, resulting in low steric hindrance and high flexibility and mobility of the ionomers and thus promoting the interdiffusion of PAA during the self-assembly. PDDA polycation shows a much better ability to block methanol crossover in comparison with that of PAH polycation. This study shows the importance of LbL self-assembled multilayer structure on the proton conductivity and methanol crossover properties of modified Nafion membranes for application in direct methanol fuel cells (DMFCs). © 2012 Elsevier B.V..
Hirt C.,Curtin University Australia
ZFV - Zeitschrift fur Geodasie, Geoinformation und Landmanagement | Year: 2011
EGM2008 is a high-resolution global model of Earth's gravity field that allows computation of quasigeoid heights and further functionals down to a resolution of 5 arc minutes. The present paper assesses EGM2008 over Germany by means of quasigeoid heights from the German GCG05 quasigeoid model and GPS/levelling points, and quasigeoid height differences from astronomical levelling. Residual terrain model (RTM) data is used for the computation of RTM quasigeoid heights, serving to augment the resolution of EGM2008 at scales shorter than 5 arc minutes. For quasigeoid heights, the comparisons show a RMS (root mean square) agreement of ~3cm between EGM2008 and GCG05 as well as EGM2008 and GPS/levelling. The residuals between EGM2008 (augmented with RTM) and astrogeodetic quasigeoid height differences are near or at the cm-level for two local test areas. The comparisons show the very good quality of EGM2008 over Germany, which serves as an example region where dense gravity sets were used for the model's development.
Iglauer S.,Curtin University Australia |
Paluszny A.,Imperial College London |
Pentland C.H.,Imperial College London |
Blunt M.J.,Imperial College London
Geophysical Research Letters | Year: 2011
Carbon capture and storage (CCS), where CO2 is injected into geological formations, has been identified as an important way to reduce CO 2 emissions to the atmosphere. While there are several aquifers worldwide into which CO2 has been injected, there is still uncertainty in terms of the long-term fate of the CO2. Simulation studies have proposed capillary trapping-where the CO2 is stranded as pore-space droplets surrounded by water-as a rapid way to secure safe storage. However, there has been no direct evidence of pore-scale trapping. We imaged trapped super-critical CO2 clusters in a sandstone at elevated temperatures and pressures, representative of storage conditions using computed micro-tomography (μ-CT) and measured the distribution of trapped cluster size. The clusters occupy 25% of the pore space. This work suggests that locally capillary trapping is an effective, safe storage mechanism in quartz-rich sandstones. © 2011 by the American Geophysical Union.
Westerveld M.F.,Griffith University |
Claessen M.,Curtin University Australia
International Journal of Speech-Language Pathology | Year: 2014
A national online survey was used to investigate spontaneous language sampling and analysis practices by speech-language pathologists working with children and adolescents. A total of 257 responses were received from clinicians around Australia. Results indicated that spontaneous language samples are collected on a routine basis in elicitation contexts deemed appropriate to the clients' age or developmental stage. However, language samples were generally short, often not recorded, and analysed informally. Consistent with previous research into language sampling practices, the main barrier to more detailed language sample analysis appears to be the time needed for transcription. Despite rapid technological advances in the last two decades, only 12.5% of the respondents reported using computer-assisted transcription and analysis procedures. Suggestions are made on how to promote change in clinical practice to ensure spontaneous language samples are transcribed and analysed in more detail. By transcribing the samples, detailed analysis of children's language performance can be undertaken, allowing for effective goal-setting and assisting in objective progress measuring during and following intervention. © 2014 The Speech Pathology Association of Australia Limited.
Wilson M.E.J.,Curtin University Australia
Geological Society Special Publication | Year: 2011
This study reviews how shallow water carbonates are revealing environmental and climatic changes on all scales through the last 50 million years in SE Asia. Marine biodiversity reaches a global maximum in the region, yet the environmental conditions are at odds with the traditional view of 'blue-water' reefal development. The region is characterized by complex tectonics, major volcanism, high terrestrial runoff, nutrient influx, everwet and monsoonal climates, low salinities, major currents and ENSO (El Niño Southern Oscillation) fluctuations. Terrestrial runoff, nutrient upwelling, tectonics, volcanism and recent human activities are major influences on the modern development of carbonate systems. Coral sclerochronology is revealing how these factors vary locally over annual and decadal scales. The strong impact of vertical tectonic movements and the interplay with eustasy is evaluated from Quaternary and Pleistocene coral reef terraces. Isotopic data from terrace deposits indicates that interglacials may have been up to 3-6 °C warmer than glacials, consistent with the region's record from terrestrial and deep marine deposits. Study of outcrop and subsurface carbonate deposits reveals the impact of tectonics, siliciclastic, nutrient influx, eustasy and oceanography on individual systems over millennial timescales. Major changes in oceanography, plate tectonics, climate change and perhaps fluctuating CO 2 levels impacted Cenozoic regional carbonate development. Results of studies from terrestrial and deep marine realms are comparable with those from the carbonates, but have yielded higher resolution records of changing currents, precipitation and the monsoons. There is considerable scope for further research, however, SE Asian carbonates are powerful tools in evaluating past environmental change in the equatorial tropics. © 2011 The Geological Society of London.
Kaczmarek M.-A.,Montpellier University |
Kaczmarek M.-A.,Curtin University Australia |
Tommasi A.,Montpellier University
Geochemistry, Geophysics, Geosystems | Year: 2011
Analysis of the microstructures in the km-scale mantle shear zone that separates the northern and the central parts of the Lanzo peridotite massif provides evidence of an evolution in time and space of deformation processes accommodating shearing in the shallow mantle within an extensional setting. This shear zone displays an asymmetric distribution of deformation facies. From south to north, gradual reorientation of the foliation of coarse porphyroclastic plagioclase-bearing peridotites is followed by development of protomylonites, mylonites, and mm-scale ultramylonite bands. A sharp grain size gradient marks the northern boundary. Early deformation under near-solidus conditions in the south is recorded by preservation of weakly deformed interstitial plagioclase and almost random clinopyroxene and plagioclase crystal orientations. Feedback between deformation and melt transport probably led to melt focusing and strain weakening in the shear zone. Overprint of melt-rock reaction microstructures by solid-state deformation and decrease in recrystallized grain size in the protomylonites and mylonites indicate continued deformation under decreasing temperature. Less enriched peridotite compositions and absence of ultramafic dykes or widespread melt-impregnation microstructures north of the shear zone and clinopyroxene and amphibole enrichment in the mylonites and ultramylonites suggest that the shear zone acted as both a thermal barrier and a high-permeability channel for late crystallizing fluids. These observations, together with chemical data indicating faster cooling of central Lanzo relative to the northern body, corroborate that this shear zone is a mantle detachment fault. All deformation facies have crystal preferred orientations consistent with deformation by dislocation creep with dominant activation of the (010) and (100) systems in olivine and orthopyroxene, respectively. Dynamic recrystallization produces dispersion of olivine CPO but not a change of dominant deformation mechanism. Evidence for activation of grain boundary sliding is limited to mm-scale ultramylonite bands, where solid-state reactions produced very fine grained polymineralic aggregates. Except for these latest stages of deformation, strain localization does not result from the microstructural evolution; the grain size decrease is a consequence of the need to deform a rock volume whose strength continuously increases because of decreasing temperature conditions. Strain localization in the intermediate levels thus essentially results from the more localizing behavior of both the deep, partially molten, and shallow parts of this extensional shear zone distribution. Copyright 2011 by the American Geophysical Union.
Schoeppe S.,Central Queensland University |
Duncan M.J.,Central Queensland University |
Badland H.,University of Melbourne |
Oliver M.,Auckland University of Technology |
Curtis C.,Curtin University Australia
Journal of Science and Medicine in Sport | Year: 2013
Health benefits from children's independent mobility and active travel beyond school travel are largely unexplored. Objectives: This review synthesized the evidence for associations of independent mobility and active travel to various destinations with physical activity, sedentary behaviour and weight status. Design: Systematic review. Methods: A systematic search in six databases (PubMed, Scopus, CINAHL, SportDiscus, PsychInfo, TRIS) for papers published between January 1990 and March 2012 was undertaken, focussing on children aged 3-18 years. Study inclusion and methodological quality were independently assessed by two reviewers. Results: 52 studies were included. Most studies focussed solely on active travel to and/or from school, and showed significant positive associations with physical activity. The same relationship was detected for active travel to leisure-related places and independent mobility with physical activity. An inverse relationship between active travel to school and weight status was evident but findings were inconsistent. Few studies examined correlations between active travel to school and self-reported screen-time or objectively measured sedentary behaviour, and findings were unclear. Conclusions: Studies on independent mobility suggested that children who have the freedom to play outdoors and travel actively without adult supervision accumulate more physical activity than those who do not. Further investigation of children's active travel to leisure-related destinations, measurement of diverse sedentary behaviour beyond simply screen-based activities, and consistent thresholds for objectively measured sedentary behaviour in children wilL clarify the inconsistent evidence base on associations of active travel with sedentary behaviour and weight status. © 2012 Sports Medicine Australia.
Hirt C.,Curtin University Australia
Computers and Geosciences | Year: 2011
Gravimetric geoid computation is often based on modified Stokes's integration, where Stokes's integral is evaluated with some stochastic or deterministic kernel modification. Accurate numerical evaluation of Stokes's integral requires the modified kernel to be integrated across the area of each discretised grid cell (mean kernel). Evaluating the modified kernel at the center of the cell (point kernel) is an approximation, which may result in larger numerical integration errors near the computation point, where the modified kernel exhibits a strongly nonlinear behavior. The present study deals with the computation of whole-of-the-cell mean values of modified kernels, exemplified here with the Featherstone-Evans-Olliver (1998) kernel modification [Featherstone, W.E., Evans, J.D., Olliver, J.G., 1998. A Meissl-modified Vaníček and Kleusberg kernel to reduce the truncation error in gravimetric geoid computations. Journal of Geodesy 72(3), 154-160]. We investigate two approaches (analytical and numerical integration), which are capable of providing accurate mean kernels. The analytical integration approach is based on kernel weighting factors which are used for the conversion of point to mean kernels. For the efficient numerical integration, Gauss-Legendre quadrature is applied. The comparison of mean kernels from both approaches shows a satisfactory mutual agreement at the level of 10-4 and better, which is considered to be sufficient for practical geoid computation requirements. Closed-loop tests based on the EGM2008 geopotential model demonstrate that using mean instead of point kernels reduces numerical integration errors by ~65%. The use of mean kernels is recommended in remove-compute-restore geoid determination with the Featherstone-Evans-Olliver (1998) kernel or any other kernel modification under the condition that the kernel changes rapidly across the cells in the neighborhood of the computation point. © 2011 Elsevier Ltd.
Maxwell P.,Curtin University Australia
Resources Policy | Year: 2015
Appreciating the pricing arrangements for a mineral and its compounds provides useful insight into the nature of its market and the industrial structure of its production. This paper focuses on the case of lithium, which has emerged from being a minor metal with limited profitable applications in 1950 to its glamour metal status some 65 years later. During this period bilateral contracts based on producer prices have been the major way in which prices have been negotiated. The entry of a major new producer (SQM) in the late 1990s led to a situation where price information was difficult to obtain, even though competition in the sector was growing. This is consistent with a movement from cooperative oligopoly to non-cooperative oligopoly. Growing price transparency since 2010 has been associated with the actual and projected entry of several new producers. With its continuing growth it seems inevitable that lithium will be formally traded on one of major metal exchanges within the next decade. In addition to this, the practice of transfer pricing between branches of established multinational producers also applies to the lithium industry. © 2015 Elsevier Ltd.
Glasser L.,Curtin University Australia
Inorganic Chemistry | Year: 2013
Entropies of solids are obtained experimentally as integrals of measured heat capacities over the temperature range from zero to ambient. Correspondingly, the Debye phonon distribution equation for solids provides a theoretical connection between these two chemical thermodynamic measures. We examine how the widely applicable Debye equation illuminates the relation between the corresponding experimental measures using more than 250 ionic solids. Estimation of heat capacities for simple ionic solids by the Dulong-Petit heat capacity limit, by the Neumann-Kopp elemental sum, and by the ion sum method is examined in relation to the Debye equation. We note that, and explain why, the ambient temperature heat capacities and entropies of ionic solids are found to be approximately equal, and how deviations from equality may be related to the Debye temperature, ΘD, which characterizes the Debye equation. It is also demonstrated that Debye temperatures may be readily estimated from the experimental ratio of ambient heat capacity to entropy, Cp/Sp, rather than requiring resort to elaborate theoretical or experimental procedures for their determination. Correspondingly, ambient mineral entropies and heat capacities are linearly correlated and may thus be readily estimated from one another. © 2013 American Chemical Society.
Plimpton S.J.,Sandia National Laboratories |
Gale J.D.,Curtin University Australia
Current Opinion in Solid State and Materials Science | Year: 2013
For this article, we call scientific software a community code if it is freely available, written by a team of developers who welcome user input, and has attracted users beyond the developers. There are obviously many such materials modeling codes. The authors have been part of such efforts for many years in the field of atomistic simulation, specifically for two community codes, the LAMMPS and GULP packages for molecular dynamics and lattice dynamics respectively. Here we highlight lessons we have learned about how to create such codes and the pros and cons of being part of a community effort. Many of our experiences are similar, but we also have some differences of opinion (like modeling vs modelling). Our hope is that readers will find these lessons useful as they design, implement, and distribute their own materials modelling software for others to use. © 2013 Elsevier Ltd. All rights reserved.
Reimers J.R.,University of Sydney |
Wang Y.,University of Sydney |
Cankurtaran B.O.,University of Technology, Sydney |
Cankurtaran B.O.,Curtin University Australia |
Ford M.J.,University of Technology, Sydney
Journal of the American Chemical Society | Year: 2010
The superatom model for nanoparticle structure is shown to be inadequate for the prediction of the thermodynamic stability of gold nanoparticles. The observed large HOMO-LUMO gaps for stable nanoparticles predicted by this model are, for sulfur-stabilized gold nanoparticles, attributed to covalent interactions of the metal with thiyl adsorbate radicals rather than ionic interactions with thiolate adsorbate ions, as is commonly presumed. In particular, gold adatoms in the stabilizing layer are shown to be of Au(0) nature, subtle but significantly different from the atoms of the gold core owing to the variations in the proportion of gold-gold and gold-sulfur links that form. These interactions explain the success of the superatom model in describing the electronic structure of both known and informatory nanoparticle compositions. Nanoparticle reaction energies are, however, found not to correlate with the completion of superatom shells. Instead, local structural effects are found to dominate the chemistry and in particular the significanctly different chemical properties of gold nanoparticle and bulk surfaces. These conclusions are drawn from density-functional-theory calculations for the Au102(p-mercaptobenzoic acid)44 nanoparticle based on the X-ray structure (Jadzinsky, P. D.; et al. Science 2007, 318, 430), as well calculations for the related Au102(S*-CH 3)44 nanoparticle, for the inner gold-cluster cores, for partially and overly reacted cores, and for Au(111) surface adsorbates. © 2010 American Chemical Society.
Glasser L.,Curtin University Australia
Inorganic Chemistry | Year: 2013
Formation enthalpies, ΔfH(298), are essential thermodynamic descriptors of the stability of materials, with many available from the numerous thermodynamic databases. However, there is a need for predictive methods to supplement these databases with missing values for known and even hypothetical materials, and also as an independent check on the not-always reliable published values. In this paper, we present 34 additive single-ion values, ΔfH(298)ion, from the formation enthalpies of 124 ionic solids, including an extensive group of silicates. In addition, we have also developed an additive set of 29 single-ion formation Gibbs energies, ΔfG(298)ion, for a smaller group of 42 materials from within the full set, constrained by the limited availability of the corresponding experimental data. Such single-ion values may be extended among related materials using simple differences from known thermodynamic values, but always with critical consideration of the results. Using the excellent available data for silicates, we propose that the solid-state silicate ion formation enthalpies can be estimated as-ΔfH(298) silicate/kJ mol-1=-252[n(Si) + n(O)]-27, where n(X) represents the number of species X in the silicate. More speculatively, we estimate the contribution per silicon and oxygen species as-490 and-184 kJ mol-1, respectively. Similarly,-ΔfG(298) silicate/kJ mol-1=-266[n(Si) + n(O)]-7, with the contribution per silicon and oxygen species being-140 and-300 kJ mol -1, respectively. We compare and contrast these results with the extensive collection of "modified lattice energy" (MLE) ion parameters from the M.S. thesis of C. D. Ratkey. Our single-ion formation enthalpies and the MLE parameters may be used in complementary predictions. While lattice energies, UPOT, entropies, So 298, and heat capacities, Cp,298, of ionic solids are reliably estimated as proportional to their formula volumes (using our Volume-Based Thermodynamic, VBT, procedures), this is not the case in general for thermodynamic formation properties, other than within select groups of related materials. © 2013 American Chemical Society.
Chaudhary D.,Curtin University Australia |
Liu H.,University of Ballarat
Ultrasonics Sonochemistry | Year: 2013
Na+-montmorillonite clay (generally referred to as MMT) is very useful for reinforcing polymeric matrix at very low concentrations (typically, 2-5% wt). These clay particles are typically exfoliated before they can demonstrate the significant gains in heat deflection temperature, modulus, and elongation properties. In the case of hydrophilic biopolymer based matrices, such as carbohydrates and chitosan, exfoliating these nanoclay particles needs greater attention because the exfoliation is typically carried out using hydrophobic oligomers through ion-exchange. This study reports a new method of synthesizing completely hydrophilic MMT-assemblages using hydrophilic plasticizers for biopolymers. We used sugar alcohols (glycerol, xylitol with 3 and 5 hydroxyl groups) and polysaccharide maltodextrin to exfoliate the MMT. Sonication was conducted for MMT nanoclay and plasticizers at different weight ratios. It was confirmed that all plasticizer/modifier led to expansion of MMT gallery spacing (d-spacing) and the change in d-spacing could be related to the molecular structure of the plasticizer. Meanwhile, the extent of exfoliation was maximum with maltodextrin (fully exfoliation with 1:10 and 1:20 ratio of MMT:plasticizer) across all test samples and interestingly, glycerol and xylitol samples quickly established within the MMT galleries and exhibited minimal influence with further increase in relative concentrations. © 2012 Elsevier B.V. All rights reserved.