Showing papers by "Queensland University of Technology published in 2001"

A logic for uncertain probabilities

Abstract: We first describe a metric for uncertain probabilities called opinion, and subsequently a set of logical operators that can be used for logical reasoning with uncertain propositions. This framework which is called subjective logic uses elements from the Dempster-Shafer belief theory and we show that it is compatible with binary logic and probability calculus.

Kirsten ras mutations in patients with colorectal cancer: the ‘RASCAL II’ study

Abstract: Researchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras incolorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P=0.004, HR 1.3) and overall survival (P=0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes' C cancers (failure-free survival, P=0.008, HR 1.5, overall survival P=0.02, HR 1.45) than in Dukes' B tumours (failure-free survival, P=0.46, HR 1.12, overall survival P=0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer. ⌐ 2001 Cancer Research Campaign.

The validity of self-reported energy intake as determined using the doubly labelled water technique.

Abstract: In the 1980s the development of the doubly labelled water (DLW) technique made it possible to determine the validity of dietary assessment methods using external, independent markers of intake in free-living populations. Since then, the accuracy of self-reported energy intake (EI) has been questioned on a number of occasions as under-reporting has been found to be prevalent in many different populations. This paper is a review of investigations using the DLW technique in conjunction with self-reported EI measures in groups including adults, children and adolescents, obese persons, athletes, military personnel and trekking explorers. In studies where a person other than the subject is responsible for recording dietary intake, such as parents of young children, EI generally corresponds to DLW determined energy expenditure. However, in instances where the subjects themselves report their intake, EI is generally under-reported when compared with energy expenditure. It was originally believed that this phenomenon of under-reporting was linked to increased adiposity and body size, however, it is now apparent that other factors, such as dietary restraint and socio-economic status, are also involved. This paper therefore aims to present a more comprehensive picture of under-reporting by tying in the findings of many DLW studies with other studies focusing particularly on the characteristics and mechanisms for under-reporting. Awareness of these characteristics and mechanisms will enable researchers to obtain more accurate self-reports of EI using all dietary recording techniques.

Mining e-mail content for author identification forensics

Abstract: We describe an investigation into e-mail content mining for author identification, or authorship attribution, for the purpose of forensic investigation. We focus our discussion on the ability to discriminate between authors for the case of both aggregated e-mail topics as well as across different e-mail topics. An extended set of e-mail document features including structural characteristics and linguistic patterns were derived and, together with a Support Vector Machine learning algorithm, were used for mining the e-mail content. Experiments using a number of e-mail documents generated by different authors on a set of topics gave promising results for both aggregated and multi-topic author categorisation.

UML Activity Diagrams as a Workflow Specification Language

Abstract: If UML activity diagrams are to succeed as a standard in the area of organisational process modeling, they need to compare well to alternative languages such as those provided by commercial Workflow Management Systems. This paper examines the expressiveness and the adequacy of activity diagrams for workflow specification, by systematically evaluating their ability to capture a collection of workflow patterns. This analysis provides insights into the relative strengths and weaknesses of activity diagrams. In particular, it is shown that, given an appropriate clarification of their semantics, activity diagrams are able to capture situations arising in practice, which cannot be captured by most commercial Workflow Management Systems. On the other hand, the study shows that activity diagrams fail to capture some useful situations, thereby suggesting directions for improvement.

An Empirical Survey of Frontier Efficiency Measurement Techniques in Education

Abstract: Educational institutions worldwide are increasingly the subject of analyses aimed at defining, measuring and improving efficiency. However, despite the importance of efficiency measurement in education, it is only relatively recently that the more advanced econometric and mathematical programming frontier techniques have been applied to primary and secondary schools, university departments and degree programmes, and universities as a whole. This paper attempts to provide a synoptic survey of the comparatively few empirical analyses in education using frontier efficiency measurement techniques. Both the measurement of inefficiency in education and the determinants of educational efficiency are examined.

The Diabetes Network Internet-Based Physical Activity Intervention: A randomized pilot study

Abstract: OBJECTIVE —Because of other competing priorities, physical activity (PA) is seldom addressed in a consistent way in either primary care or diabetes education . This 8-week pilot study evaluated the short-term benefits of an Internet-based supplement to usual care that focused on providing support for sedentary patients with type 2 diabetes to increase their PA levels. RESEARCH DESIGN AND METHODS —A total of 78 type 2 diabetic patients (53% female, average age 52.3 years) were randomized to the Diabetes Network (D-Net) Active Lives PA Intervention or an Internet information-only condition. The intervention condition received goal-setting and personalized feedback, identified and developed strategies to overcome barriers, received and could post messages to an on-line “personal coach,” and were invited to participate in peer group support areas. Key outcomes included minutes of PA per week and depressive symptomatology. RESULTS —There was an overall moderate improvement in PA levels within both intervention and control conditions, but there was no significant improvement in regard to condition effects. There was substantial variability in both site use and outcomes within the intervention and control conditions. Internal analyses revealed that among intervention participants, those who used the site more regularly derived significantly greater benefits, whereas those in the control condition derived no similar benefits with increased program use. CONCLUSIONS —Internet-based self-management interventions for PA and other regimen areas have great potential to enhance the care of diabetes and other chronic conditions. We conclude that greater attention should be focused on methods to sustain involvement with Internet-based intervention health promotion programs over time.

Representation results for defeasible logic

Abstract: The importance of transformations and normal forms in logic programming, and generally in computer science, is well documented. This paper investigates transformations and normal forms in the context of Defeasible Logic, a simple but efficient formalism for nonmonotonic reasoning based on rules and priorities. The transformations described in this paper have two main benefits: on one hand they can be used as a theoretical tool that leads to a deeper understanding of the formalism, and on the other hand they have been used in the development of an efficient implementation of defeasible logic.

Job satisfaction and teamwork: The role of supervisor support

Abstract: The link between teamwork and job satisfaction was investigated in a sample of 48 manufacturing companies comprising 4708 employees. Two separate research questions were addressed. First, it was proposed that supervisor support would be a weaker source of job satisfaction in companies with higher levels of teamworking. Multilevel analysis indicated that the extent of teamwork at the company level of analysis moderated the relationship between individual perceptions of supervisor support and job satisfaction. Second, it was proposed that the extent of teamwork would be positively related to perceptions of job autonomy but negatively related to perceptions of supervisor support. Further, it was proposed that the link between teamwork and job autonomy would be explained by job enrichment practices associated with teamwork. Analyses of aggregated company data supported these propositions and provided evidence for a complex mediational path between teamwork and job satisfaction. Implications for implementing teamwork in organizations are discussed. Copyright © 2001 John Wiley & Sons, Ltd.

Plantar pressure differences between obese and non-obese adults: a biomechanical analysis.

Abstract: OBJECTIVE: To investigate plantar pressure differences between obese and non-obese adults during standing and walking protocols using a pressure distribution platform. SUBJECTS: Thirty-five males (age 42.4±10.8 y; 67–179 kg) and 35 females (age 40.0±12.6 y; 46–150 kg) divided into obese (body mass index (BMI) 38.75±5.97 kg/m2) and non-obese (BMI 24.28±3.00 kg/m2) sub-groups, respectively. MEASUREMENTS: Data collection was performed with a capacitive pressure distribution platform with a resolution of 2 sensors/cm2 (Emed F01, Novel GmbH, Munchen). The measurement protocol included half and full body weight standing on the left, right and both feet, respectively, and walking across the platform, striking with the right foot. Pressures were evaluated for eight anatomical sites under the feet. RESULTS: For both men and women, the mean pressure values of the obese were higher under all anatomical landmarks during half body weight standing. Significant increases in pressure were found under the heel, mid-foot and metatarsal heads II and IV for men and III and IV for women. Foot width during standing was also significantly increased in obese subjects. For walking, significantly higher peak pressures were also found in both obese males and females. CONCLUSION: Compared to a non-obese group, obese subjects showed increased forefoot width and higher plantar pressures during standing and walking. The greatest effect of body weight on higher peak pressures in the obese was found under the longitudinal arch of the foot and under the metatarsal heads. The higher pressures for obese women compared to obese men during static weight bearing (standing) may be the result of reduced strength of the ligaments of the foot.

Early diagnosis of lymphedema using multiple frequency bioimpedance.

Abstract: Multiple frequency bioelectrical impedance analysis (MFBIA) has previously been shown to provide accurate relative measures of lymphedema in the upper limb of patients (1). This paper reports the results of a three year prospective study to evaluate the efficacy of MFBIA to predict the early onset of lymphedema in patients following treatment for breast cancer. Bioelectrical impedance measurements and circumferential measurements of each upper limb were recorded in healthy control subjects (n=60) to determine the normal range of the ratio (dominant/non-dominant) of extracellular and total limb volumes respectively. Patients undergoing surgery for the treatment of breast cancer were recruited as the study group; MFBIA and circumferential measurements were recorded pre-surgery, one month post-surgery and then at two month intervals for 24 months. One hundred and two patients were recruited into the study. Twenty patients developed lymphedema in the 24 months follow up period of this study. In each of these 20 cases MFBIA predicted the onset of the condition up to 10 months before the condition could be clinically diagnosed. Estimates of the sensitivity and specificity were both approximately 100%. At the time of detection by MFBIA, only one of the patients returned a positive test result from the total limb volumes determined from the circumferential measures. These results confirmed the suitability of the MFBIA technique as a reliable diagnostic procedure for the early detection of lymphedema.

Childhood socioeconomic position and cognitive function in adulthood

Abstract: *This article is free to read on the publisher's website* Background Risk of dementia and Alzheimer's disease is higher among adults with limited education, and the less educated perform poorer on cognitive function tests. This study determines whether the socioeconomic environment experienced during childhood has an impact on cognitive functioning in middle age. Methods A population-based study of eastern Finnish men (n = 496) aged 58 and 64 for whom there were data on parent's socioeconomic position (SEP), their own education level, and performance on neuropsychological tests. Cognitive function was measured using the Trail Making Test, the Selective Reminding Test, the Verbal Fluency Test, the Visual Reproduction Test, and the Mini Mental State Exam. Results We found a significant and graded association between parental SEP (combined as an index) and cognitive function both prior to and after adjustment for respondent's education. Those from more disadvantaged backgrounds exhibited the poorest performance. When the separate components of the parental SEP measure were used, father's occupation and mother's education were independently associated with the respondent's score for three and five of the tests, respectively (there was no association with father's education and mother's occupation). After adjustment for the respondent's education, father's occupation was no longer associated with respondent's test score, however, the results were essentially unchanged for mother's education. Conclusions Higher SEP during childhood and greater educational attainment are both associated with cognitive function in adulthood, with mothers and fathers each contributing to their offspring's formative cognitive development and later life cognitive ability (albeit in different ways). Improvements in both parental socioeconomic circumstances and the educational attainment of their offspring could possibly enhance cognitive function and decrease risk of dementia later in life.

Socioeconomic inequalities in all-cause and specific-cause mortality in Australia: 1985–1987 and 1995–1997

Abstract: Background. Socioeconomic inequalities in mortality have been repeatedly observed in Britain, the United States, and Europe, and in some countries, there is evidence that the differentials are widening. This study describes trends in socioeconomic mortality inequality in Australia for males and females aged 0-14, 15-24 and 25-64 years over the period 1985-87 to 1995-97. Methods. SES was operationalised using the Index of Relative Socioeconomic Disadvantage, an area based measure developed by the Australian Bureau of Statistics. Mortality differentials were examined using age-standardised rates, and mortality inequality was assessed using rate ratios, gini coefficients, and a measure of excess mortality. Results. For both periods, and for each sex/age sub-group, mortality rates were highest in the most disadvantaged areas. The extent and nature of socioeconomic mortality inequality differed for males and females and for each age group: both increases and decreases in mortality inequality were observed, and for some causes, the degree of inequality remained unchanged. If it were possible to reduce death rates among the SES areas to a level equivalent to that of the least disadvantaged area, premature all–cause mortality for males in the three age groups would be lower by 22%, 28% and 26% respectively, and for females, 35%, 70% and 56%. Conclusions. The mortality burden in the Australian population attributable to socioeconomic inequality is large, and has profound and far-reaching implications in terms of the unnecessary loss of life, the loss of potentially economically productive members of society, and increased costs for the health care system. Keywords: Socioeconomic status, mortality inequality, Australia, area-based measures.

A Multidimensional Approach to the Group Cohesion-Group Performance Relationship

Abstract: This study (a) examined the multidimensionality of both group cohesion and group performance, (b) investigated the relationship between group-level task and social cohesion and group effectiveness, and (c) examined the longitudinal changes in cohesion and performance and the direction of effect between cohesion and performance. First, the authors hypothesized that both task and social cohesion would predict positively all dimensions of group performance. Second, that a stronger relationship would be observed between task cohesion and task effectiveness and between social cohesion and system viability. Third, that all dimensions of cohesion and performance would increase over time. Finally, that cohesion would be both the antecedent and the consequence of performance but that the performance-cohesion relationship would be stronger than the cohesion-performance relationship. Results supported the hypothesized one-to-one relationship between specific dimensions of group cohesion and group performance. Task cohesion was the sole predictor of self-rated performance at both Time 1 and Time 2, whereas social cohesion was the only predictor of system viability at Time 1 and the stronger predictor at Time 2. Social cohesion at Time 2 predicted performance on group task. However, no longitudinal changes were found in cohesion or performance. Finally, group cohesion was found to be the antecedent, but not the consequence, of group performance.

Comparison of Raman spectra in characterizing gibbsite, bayerite, diaspore and boehmite

Abstract: High-quality Raman spectra were used for the characterization of alumina phases of gibbsite, bayerite, diaspore and boehmite. The Raman spectrum of gibbsite shows four strong, sharp bands at 3617, 3522, 3433 and 3364 cm in the hydroxyl stretching region. The spectrum of bayerite shows seven bands at 3664, 3652, 3552, 3542, 3450, 3438 and 3420 cm. Five broad bands at 3445, 3363, 3226, 3119 and 2936 cm and four broad and weak bands at 3371, 3220, 3085 and 2989 cm-1 are present in the Raman spectrum of the hydroxyl stretching region of diaspore and boehmite. The hydroxyl stretching bands are related to the surface structure of the minerals. The Raman spectra of bayerite, gibbsite and diaspore are complex whereas the Raman spectrum of boehmite shows only four bands in the low-wavenumber region. These bands are assigned to deformation and translational modes of the alumina phases. A comparison of the Raman spectrum of bauxite with those of boehmite and gibbsite showed the possibility of using Raman spectroscopy for on-line processing of bauxites that contain a mixture of alumina phases.

Porous Clays and Pillared Clays-Based Catalysts. Part 2: A review of the Catalytic and Molecular Sieve Applications

Abstract: Metal oxide pillared clay (PILC) possesses several interesting properties, such as large surface area, high pore volume and tunable pore size (from micropore to mesopore), high thermal stability, strong surface acidity and catalytic active substrates/metal oxide pillars. These unique characteristics make PILC an attractive material in catalytic reactions. It can be made either as catalyst support or directly used as catalyst. This paper is a continuous work from Kloprogge's review (J.T. Kloprogge, J. Porous Mater. 5, 5 1998) on the synthesis and properties of smectites and related PILCs and will focus on the diverse applications of clay pillared with different types of metal oxides in the heterogeneous catalysis area and adsorption area. The relation between the performance of the PILC and its physico-chemical features will be addressed.

Reversal of cardiac and renal fibrosis by pirfenidone and spironolactone in streptozotocin-diabetic rats.

Abstract: Fibrosis leads to chronic impairment of cardiac and renal function and thus reversal of existing fibrosis may improve function and survival. This project has determined whether pirfenidone, a new antifibrotic compound, and spironolactone, an aldosterone antagonist, reverse both deposition of the major extracellular matrix proteins, collagen and fibronectin, and functional changes in the streptozotocin(STZ)-diabetic rat. Streptozotocin (65 mg kg(-1) i.v.)-treated rats given pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone; approximately 200 mg kg(-1) day(-1) as 0.2 - 2g 1(-1) drinking water) or spironolactone (50 mg kg(-1) day(-1) s.c.) for 4 weeks starting 4 weeks after STZ showed no attenuation of the increased blood glucose concentrations and increased food and water intakes which characterize diabetes in this model. STZ-treatment increased perivascular and interstitial collagen deposition in the left ventricle and kidney, and surrounding the aorta. Cardiac, renal and plasma fibronectin concentrations increased in STZ-diabetic rats. Passive diastolic stiffness increased in isolated hearts from STZ-diabetic rats. Both pirfenidone and spironolactone treatment attenuated these increases without normalizing the decreased +dP/dt(max) of STZ-diabetic hearts. Left ventricular papillary muscles from STZ-treated rats showed decreased maximal positive inotropic responses to noradrenaline, EMD 57033 (calcium sensitizer) and calcium chloride; this was not reversed by pirfenidone or spironolactone treatment. STZ-treatment transiently decreased GFR and urine flow rates in isolated perfused kidneys; pirfenidone but not spironolactone prevented the return to control values. Thus, short-term pirfenidone and spironolactone treatment reversed cardiac and renal fibrosis and attenuated the increased diastolic stiffness without normalizing cardiac contractility or renal function in STZ-diabetic rats.

Spectral Analysis of Fractional Kinetic Equations with Random Data

Abstract: We present a spectral representation of the mean-square solution of the fractional kinetic equation (also known as fractional diffusion equation) with random initial condition. Gaussian and non-Gaussian limiting distributions of the renormalized solution of the fractional-in-time and in-space kinetic equation are described in terms of multiple stochastic integral representations.

Separating more sources than sensors using time-frequency distributions

Abstract: This paper deals with the problem of blind source separation of nonstationary signals of which only instantaneous linear signals are observed. Exploiting the effectiveness of time-frequency signal processing for nonstationary signals, a blind source separation approach is considered using the observation spatial time-frequency distributions (STFD). Existing solutions are bound to the situation in which the number of sources being separated is less than the number of available sensors measuring the mixed sources. We consider the more general case when we can have more sources than sensors assuming that the former are "separable" in the time-frequency domain. The proposed solution proceeds through 3 main steps: (i) a testing procedure is applied (after whitening the STFD) to first separate the cross-terms from auto-terms; (ii), source separation in the time-frequency domain (from the autoterms only) using a vector classification approach; and finally (iii), obtaining the source signatures using time-frequency synthesis.

Technology and humane nursing care: (ir)reconcilable or invented difference?

Abstract: Technology and humane nursing care: (ir)reconcilable or invented difference? Aim(s) of the paper. This paper questions the validity of a boundary presumed to exist between technology and humane care. It argues the need for reconciliation of presumed tension(s) between technology and person focused care and the need to reconsider our ways of understanding the relations between technology and nursing. Background/rationale. Recent scholarship in the social sciences related to reproductive and imaging technologies and emergency resuscitation are examined and arguments are presented that question the appropriateness of a humanist view that emphasizes technology on the nonhuman and nonnatural side of a human/nonhuman, nature/artifice divide. It is argued that what determines experiences such as dehumanization is not technology per se but how individual technologies are used and operate in specific user contexts, the meanings that are attributed to them, how individuals or cultural groups define what is human, and the organizational, human, political and economic technological system (technique) that creates rationale and efficient order within nursing, health care and society. Conclusion. The paper concludes by asking whether the commonplace appeal to resolve tensions between humane care and technology has erroneously highlighted technology as the reason for impersonal care, and encourages re-examination of the relationship(s) between technology, humane care and nursing practice.

Electrophoretic deposition of hydroxyapatite coatings on metal substrates : A nanoparticulate dual-coating approach

Abstract: Hydroxyapatite coatings can be readily deposited on metal substrates by electrophoretic deposition. However, subsequent sintering is highly problematic owing to the fact that temperatures in excess of 1100°C are required for commercial hydroxyapatite powders to achieve high density. Such temperatures damage the metal and induce metal-catalysed decomposition of the hydroxyapatite. Furthermore, the firing shrinkage of the hydroxyapatite coating on a constraining metal substrate leads to severe cracking. The present study has overcome these problems using a novel approach: the use of aged nanoparticulate hydroxyapatite sols (lower sintering temperature) and a dual coating strategy that overcomes the cracking problem. Dual layers of uncalcined hydroxyapatite (HAp) powder were electrophoretically coated on Ti, Ti6Al4V and 316L stainless steel metal substrates, sintered at 875–1000°C, and characterised by SEM and XRD, and interfacial shear strength measurement. Dual coatings on stainless steel had an average high bond strength (about 23 MPa), and dual coatings on titanium and titanium alloy had moderate strengths (about 14 and 11 MPa, respectively), in comparison with the measured shear strength of bone (35 MPa). SEM and XRD demonstrated that the second layer blended seamlessly with the first and filled the cracks in the first. The superior result on stainless steel is attributed to a more appropriate thermal expansion match with hydroxyapatite, the thinner oxide layer, or a combination of these factors.