Showing papers by "Curtin University published in 2004"

The worldwide leaf economics spectrum

Abstract: Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients and dry mass in leaves, and operates largely independently of growth form, plant functional type or biome. Categories along the spectrum would, in general, describe leaf economic variation at the global scale better than plant functional types, because functional types overlap substantially in their leaf traits. Overall, modulation of leaf traits and trait relationships by climate is surprisingly modest, although some striking and significant patterns can be seen. Reliable quantification of the leaf economics spectrum and its interaction with climate will prove valuable for modelling nutrient fluxes and vegetation boundaries under changing land-use and climate.

Emerging flaviviruses: the spread and resurgence of Japanese encephalitis, West Nile and dengue viruses

Abstract: Mosquito-borne flaviviruses provide some of the most important examples of emerging and resurging diseases of global significance. Here, we describe three of them: the resurgence of dengue in tropical and subtropical areas of the world, and the spread and establishment of Japanese encephalitis and West Nile viruses in new habitats and environments. These three examples also illustrate the complexity of the various factors that contribute to their emergence, resurgence and spread. Whereas some of these factors are natural, such as bird migration, most are due to human activities, such as changes in land use, water impoundments and transportation, which result in changed epidemiological patterns. The three examples also show the ease with which mosquito-borne viruses can spread to and colonize new areas, and the need for continued international surveillance and improved public health infrastructure to meet future emerging disease threats.

Factors Affecting the Success of a Construction Project

Abstract: Different researchers have tried to determine the factors for a successful project for a long time. Lists of variables have been abounded in the literature, however, no general agreement can be made. The aim of this paper is to develop a conceptual framework on critical success factors (CSFs). Seven major journals in the construction field are chosen to review the previous works on project success. Five major groups of independent variables, namely project-related factors, project procedures, project management actions, human-related factors, and external environment are identified as crucial to project success. Further study on the key performance indicators (KPIs) is needed to identify the causal relationships between CSFs and KPIs. The causal relationships, once identified, will be a useful piece of information to implement a project successfully.

Inquiry in science education: International perspectives

Abstract: This paper set emerged from an international symposium that aimed to shed light on issues associated with the enactment of inquiry both as means (i.e., inquiry as an in- structional approach) and as ends (i.e., inquiry as a learning outcome) in precollege science classrooms. The symposium contributors were charged with providing perspectives from

Optimum control strategies in energy conversion of PMSG wind turbine system without mechanical sensors

Abstract: The amount of energy obtained from a wind energy conversion system (WECS) depends not only on the characteristics of the wind regime at the site, but it also depends on the control strategy used for the WECS. In order to determine the gain in energy derived from one concept as compared against another, models of several autonomous WECS have been developed using Matlab Simulink software. These allow easy performance evaluations and comparisons on different control strategies used, and determine the amount of energy injected to the grid in the case of the grid-connected systems. This paper also proposes a prototype version of the control strategy of a 20-kW permanent-magnet synchronous generator (PMSG) for maximum power tracking and compares with the results produced by previous strategies. Advantages of this mechanical sensorless control strategy for maximum power estimation are demonstrated by digital simulation of the system.

Action Research in Education

Abstract: This article presents an overview of the development and current status of action research. Emerging first in the 1940s, this form of inquiry has recently gained increasing credibility in the academic world as a form of inquiry particularly relevant to the professions. The article describes the variety of definitions, approaches, and perspectives encompassed by those who practice action research, and provides insight into the philosophical differences that underpin these different orientations. It also describes the different applications of action research in educational settings, including its use in practitioner research, teacher education, professional development, curriculum development, evaluation, policy development, and social change.

Species coextinctions and the biodiversity crisis.

Abstract: To assess the coextinction of species (the loss of a species upon the loss of another), we present a probabilistic model, scaled with empirical data. The model examines the relationship between coextinction levels (proportion of species extinct) of affiliates and their hosts across a wide range of coevolved interspecific systems: pollinating Ficus wasps and Ficus, parasites and their hosts, butterflies and their larval host plants, and ant butterflies and their host ants. Applying a nomographic method based on mean host specificity (number of host species per affiliate species), we estimate that 6300 affiliate species are “coendangered” with host species currently listed as endangered. Current extinction estimates need to be recalibrated by taking species coextinctions into account.

Association of domestic exposure to volatile organic compounds with asthma in young children

Abstract: Aim: To investigate the association between domestic exposure to volatile organic compounds (VOCs) and asthma in young children. Methods: A population based case-control study was conducted in Perth, Western Australia in children aged between 6 months and 3 years. Cases (n = 88) were children recruited at Princess Margaret Hospital accident and emergency department and discharged with asthma as the primary diagnosis; 104 controls consisted of children from the same age group without an asthma diagnosis identified through the Health Department of Western Australia. Information regarding the health status of the study children and characteristics of the home was collected using a standardised questionnaire. Exposure to VOCs, average temperature and relative humidity were measured in winter and summer in the living room of each participating household. Results: Cases were exposed to significantly higher VOC levels (μg/m 3 ) than controls (p 3 ) the risk of having asthma increased by almost two and three times, respectively. Conclusions: Domestic exposure to VOCs at levels below currently accepted recommendations may increase the risk of childhood asthma. Measurement of total VOCs may underestimate the risks associated with individual compounds.

Recovery of Faunal Communities During Tropical Forest Regeneration

Abstract: As mature tropical forests are cleared, secondary forests may play an important role in the con- servation of animal species, depending on how fast animal communities recover during forest regeneration. I reviewed published studies on the recovery of animal species richness and composition during tropical forest regeneration. In 38 of the 39 data sets I examined, conversion of forest to agriculture or pasture substantially reduced species richness. Given suitable conditions for forest recovery, the species richness of the animal taxa considered can be predicted to resemble that of mature forests roughly 20-40 years after land abandonment. At least for ants and birds, however, recovery of species composition appears to take substantially longer than recovery of species richness. Because species richness for many taxa appears to recover relatively rapidly in secondary forests, conservation of secondary forests may be an effective investment in future diversity. The slower recovery of species composition indicates, however, that some species will require stands of mature forest to persist.

Ants show the way Down Under: invertebrates as bioindicators in land management

Abstract: The sight of land managers poring over ant checklists is a regular occurrence in Australia, where ant monitoring has been successfully applied to a wide range of land-use situations. The robustness of ants as ecological indicators has been consistently demonstrated, and is supported by an extensive understanding of their community dynamics in relation to disturbance. Despite the widespread recognition of the value of terrestrial invertebrates as bioindicators, the use of ants represents one of the few examples where invertebrates are widely adopted in land management as indicator organisms, as opposed to being consigned to the “too hard” basket. The use of invertebrates as bioindicators in land management will always require specialist expertise and a substantial investment in resources. However, research in Australia shows that invertebrate monitoring does not require comprehensive surveys, and that it is possible to simplify sampling and processing without compromising indicator performance. This should...

Protective effect of green tea against prostate cancer: a case-control study in southeast China.

Abstract: To investigate whether green tea consumption has an etiological association with prostate cancer, a case-control study was conducted in Hangzhou, southeast China during 2001-2002. The cases were 130 incident patients with histologically confirmed adenocarcinoma of the prostate. The controls were 274 hospital inpatients without prostate cancer or any other malignant diseases, and matched to the age of cases. Information on duration, quantity and frequency of usual tea consumption, as well as the number of new batches brewed per day, were collected by face-to-face interview using a structured questionnaire. The risk of prostate cancer for tea consumption was assessed using multivariate logistic regression adjusting for age, locality, education, income, body mass index, physical activity, alcohol consumption, tobacco smoking, total fat intake, marital status, age at marriage, number of children, history of vasectomy and family history of prostate cancer. Among the cases, 55.4% were tea drinkers compared to 79.9% for the controls. Almost all the tea consumed was green tea. The prostate cancer risk declined with increasing frequency, duration and quantity of green tea consumption. The adjusted odds ratio (OR), relative to non-tea drinkers, were 0.28 (95% CI = 0.17-0.47) for tea drinking, 0.12 (95% CI = 0.06-0.26) for drinking tea over 40 years, 0.09 (95% CI = 0.04-0.21) for those consuming more than 1.5 kg of tea leaves yearly, and 0.27 (95% CI = 0.15-0.48) for those drinking more than 3 cups (1 litre) daily. The dose response relationships were also significant, suggesting that green tea is protective against prostate cancer.

Linguistic Distance: A Quantitative Measure of the Distance Between English and Other Languages

Abstract: This paper develops a scalar or quantitative measure of the "distance" between English and a myriad of other (non-native American) languages. This measure is based on the difficulty Americans have learning other languages. The linguistic distance measure is then used in an analysis of the determinants of English language proficiency among adult immigrants in the United States and Canada. It is shown that, when other determinants of English language proficiency are the same, the greater the measure of linguistic distance, the poorer is the respondent's English language proficiency. This measure can be used in research, evaluation and practitioner analyses, and for diagnostic purposes regarding linguistic minorities in English-speaking countries. The methodology can also be applied to develop linguistic distance measures for other languages.

Determinants of Innovation

Abstract: The study examines how firm size, market structure, profitability and growth influence innovative activity in small to medium sized Australian manufacturing businesses, using the recently released Confidentialised Unit Record File drawn from the Business Longitudinal Survey of the Australian Bureau of Statistics. Regression analysis is conducted to determine the factors that effect subsequent innovative activity for the full sample of businesses, as well as for sub-samples of firms from high and low-technological opportunity industries. Most variables, including size, R&D intensity, market structure and trade shares are found to be conducive to further innovative activity for the full sample and for high-tech firms. For low-tech industries, fewer variables are significant.

Harm minimization in school drug education: final results of the School Health and Alcohol Harm Reduction Project (SHAHRP).

Abstract: Aims The School Health and Alcohol Harm Reduction Project (SHAHRP study) aimed to reduce alcohol-related harm in secondary school students. Design The study used a quasi-experimental research design in which randomly selected and allocated intervention and comparison groups were assessed at eight, 20 and 32 months after baseline. Setting Metropolitan, government secondary schools in Perth, Western Australia. Participants The sample involved over 2300 students. The retention rate was 75.9% over 32 months. Intervention The evidence-based intervention, a curriculum programme with an explicit harm minimization goal, was conducted in two phases over a 2year period. Measures Knowledge, attitude, total alcohol consumption, risky consumption, context of use, harm associated with own use and harm associated with other people’s use of alcohol. Findings There were significant knowledge, attitude and behavioural effects early in the study, some of which were maintained for the duration of the study. The intervention group had significantly greater knowledge during the programme phases, and significantly safer alcohol-related attitudes to final followup, but both scores were converging by 32 months. Intervention students were significantly more likely to be non-drinkers or supervised drinkers than were comparison students. During the first and second programme phases, intervention students consumed 31.4% and 31.7% less alcohol. Differences were converging 17 months after programme delivery. Intervention students were 25.7%, 33.8% and 4.2% less likely to drink to risky levels from first follow-up onwards. The intervention reduced the harm that young people reported associated with their own use of alcohol, with intervention students experiencing 32.7%, 16.7% and 22.9% less harm from first follow-up onwards. There was no impact on the harm that students reported from other people’s use of alcohol. Conclusions The results of this study support the use of harm reduction goals and classroom approaches in school drug education.

Optimal placement, replacement and sizing of capacitor Banks in distorted distribution networks by genetic algorithms

Abstract: This paper presents a new genetic algorithm (GA)-based approach for the simultaneous power quality improvement and optimal placement and sizing of fixed capacitor banks in radial distribution networks in the presence of voltage and current harmonics. The objective function includes the cost of power losses, energy losses and that of the capacitor banks. Constraints include voltage limits, number/size and locations of installed capacitors (at each bus and the entire feeder) and the power quality limits of standard IEEE-519. Candidate buses for capacitor placement are selected based on an initial generation of chromosomes. Using a proposed fitness function, a suitable combination of objective and constraints is defined as a criterion to select (among the candidates) the most suitable buses for capacitor placement. A genetic algorithm computes improved generations of chromosomes and candidate buses until the solution is obtained. Simulation results for two IEEE distorted networks are presented and solutions of the genetic algorithm are compared with those of the maximum-sensitivities-selection (MSS), the maximum sensitivities selection-local variations (MSS-LV), and the fuzzy set algorithms. The main contribution of this paper is the computation of the near global solution, with weak dependency on initial conditions.

Management of risks in information technology projects

Abstract: Information technology (IT) projects are renowned for their high failure rate. Risk management is an essential process for the successful delivery of IT projects. In‐depth interviews with IT professionals from leading firms in Western Australia were undertaken to determine how IT risks were managed in their projects. The respondents ranked 27 IT risks in terms of likelihood and consequences to identify the most important risks. The top five risks, in order, were: personnel shortfalls; unreasonable project schedule and budget; unrealistic expectations; incomplete requirements; and diminished window of opportunity due to late delivery of software. The respondents overwhelmingly applied the treatment strategy of risk reduction to manage these risks. Furthermore, these strategies were primarily project management processes, rather than technical processes. This demonstrates that project management is a risk management strategy. Scope, quality management, and human resource management were solutions applied to several risks. In particular, managing stakeholders’ expectations is a specific risk treatment that helps to manage several key IT risks.

Incomplete retention of radiation damage in zircon from Sri Lanka

Abstract: A suite of 18 zircon gemstones from placers in the Highland/Southwestern Complex, Sri Lanka, were subjected to a comprehensive study of their radiation damages and ages. The investigation included X-ray diffraction, Raman and PL spectroscopy, electron microprobe, PIXE and HRTEM analysis, as well as (U-Th)/He and SHRIMP U-Th-Pb age determinations. Zircon samples described in this study are virtually homogeneous. They cover the range from slightly metamict to nearly amorphous. Generally concordant U-Th-Pb ages averaging 555 ± 11 Ma were obtained. Late Ordovician zircon (U-Th)/He ages scattering around 443 ± 9 Ma correspond reasonably well with previously determined biotite Rb-Sr ages for rocks from the HSWC. Slightly to moderately metamict zircon has retained the radiogenic He whereas only strongly radiation-damaged zircon (calculated total fluences exceeding ~3.5 × 10 18 α-events/g) has experienced significant He loss. When compared to unannealed zircon from other localities, Sri Lanka zircon is about half as metamict as would correspond to complete damage accumulation over a ~555 m.y. lasting self-irradiation period, suggesting significant annealing of the structural radiation damage. Insufficient consideration of this has often resulted in significant underestimation of radiation effects in zircon. We suggest to estimate “effective α-doses” for Sri Lanka zircon by multiplying total α-fluences, which were calculated using the zircon U-Th-Pb age, by a correction factor of 0.55. This conversion may be applied to literature data as well, because all gem-zircon samples from Sri Lanka (this work and previous studies) seem to reveal the same general trends of property changes depending on the radiation damage. The use of “effective α-doses” for Sri Lanka zircon contributes to more reliable quantitative estimates of radiation effects and makes possible direct comparison between natural and synthetic radiation-damaged zircon.

The nature of learning and its implications for research on learning from museums

Abstract: The last decade has brought considerable progress in our understanding of how institutions like museums affect people's lives. However, there is still a great deal we do not know, and the research challenges ahead sometimes appear quite daunting. In this paper, we suggest that three characteristics of learning, its personal nature, that it is contextualized, and that it takes time, are critical to understanding and investigating the impact that museums have on people's lives. These characteristics have long been recognized, and we believe that recent research has emphasized their importance, but they are yet to be consistently well addressed in research. In the paper, each characteristic is elaborated and its implications for research examined. In particular, we argue that a search for a wider range of learning outcomes, the use of a wider range of research methods, and a greater consideration for, and recognition of, the significance of time are the principles for the future research agenda.

Understanding the grey entrepreneur

Abstract: Demographic trends in the developed world indicate that older entrepreneurs will play an increasingly important part of economic activity as populations age, yet this cohort has been largely ignored in entrepreneurship research. This paper provides an overview of current research about the so-called "grey entrepreneur" (also known as senior, older, third age or elderly entrepreneurs), drawing on research from a number of nations. The extant literature indicates that a majority of older entrepreneurs are male, although the number of older female entrepreneurs is increasing; they are also less likely to possess formal educational qualifications than younger entrepreneurs. Some of the advantages that such entrepreneurs possess include greater levels of technical, industrial and management experience; superior personal networks; and a stronger financial asset base. Some of the disadvantages or potential barriers faced by older entrepreneurs can include lower levels of health, energy and productivity; ageism; and the value that his or her society places on active ("productive") ageing. Numerous issues still remain to be investigated in this field of research. These include the differences between younger and older entrepreneurs; their motives and success criteria; the impact of financial, knowledge and other resources on venturing behaviour; the role of government policies in fostering or hampering individual enterprise; and the significance of cultural differences amongst older entrepreneurs. Research in this field is currently also hampered by a multiplicity of terms and definitions, a lack of age-related data about different entrepreneurial cohorts, and the problems inherent in operationalising the concept of the "grey entrepreneur."

Project success — a survey

Abstract: Over the past decade there has been a growing literature on project success criteria, however there has been relatively little empirical data. This paper provides a significant contribution to the knowledge of project success by providing empirical data on the subject, by means of a survey of 150 Australian project managers on the subject of project success criteria. An analysis of the data found two distinct views: those that perceived project success solely in terms of the traditional project objectives of time, cost and quality; and those that considered success in terms of these objectives and the effectiveness of the project's product. The traditional project management success criteria of time, cost and quality still has a strong hold within the project management community in Australia. However, the most important success criterion was considered to be the product success criterion of meeting the owner's needs.