Showing papers by "University of Wollongong published in 1997"
TL;DR: The results suggest that in this human population, as in animal models, skeletal muscle insulin sensitivity is strongly influenced by local supplies of triglycerides, as well as by remote depots and circulating lipids.
Abstract: In animal studies, increased amounts of triglyceride associated with skeletal muscle (mTG) correlate with reduced skeletal muscle and whole body insulin action. The aim of this study was to test this relationship in humans. Subjects were 38 nondiabetic male Pima Indians (mean age 28 ± 1 years). Insulin sensitivity at physiological ( M ) and supraphysiological ( MZ ) insulin levels was assessed by the euglycemic clamp. Lipid and carbohydrate oxidation were determined by indirect calorimetry before and during insulin administration. mTG was determined in vastus lateralis muscles obtained by percutaneous biopsy. Percentage of body fat (mean 29 ± 1%, range 14–44%) was measured by underwater weighing. In simple regressions, negative relationships were found between mTG (mean 5.4 ± 0.3 μmol/g, range 1.3–1.9 μmol/g) and log10 M ( r = −0.53, P ≤ 0.001), MZ ( r = −0.44, P = 0.006), and nonoxidative glucose disposal ( r = −0.48 and −0.47 at physiological and supraphysiological insulin levels, respectively, both P = 0.005) but not glucose or lipid oxidation. mTG was not related to any measure of adiposity. In multiple regressions, measures of insulin resistance (log10 M , MZ , log10[fasting insulin]) were significantly related to mTG independent of all measures of obesity (percentage of body fat, BMI, waist-to-thigh ratio). In turn, all measures of obesity were related to the insulin resistance measures independent of mTG. The obesity measures and mTG accounted for similar proportions of the variance in insulin resistance in these relationships. The results suggest that in this human population, as in animal models, skeletal muscle insulin sensitivity is strongly influenced by local supplies of triglycerides, as well as by remote depots and circulating lipids. The mechanism(s) underlying the relationship between mTG and insulin action on skeletal muscle glycogen synthesis may be central to an understanding of insulin resistance.
1,180 citations
TL;DR: A model that includes a redintegration process that operates to "clean up" decayed short-term memory traces is proposed and the multinomial processing tree model described by R. Schweickert (1993) is used to provide a quantitative fit to data from Experiments 2, 3, and 4.
Abstract: Four experiments investigated the mechanisms responsible for the advantage enjoyed by high-frequency words in short-term memory tasks. Experiment 1 demonstrated effects of word frequency on memory span that were independent of differences in speech rate. Experiments 2 and 3 showed that word frequency has an increasing effect on serial recall across serial positions, but Experiment 4 showed that this effect was abolished for backward recall. A model that includes a redintegration process that operates to ''clean up'' decayed short-term memory traces is proposed, and the multinomial processing tree model described by R. Schweickert (1993) is used to provide a quantitative fit to data from Experiments 2, 3, and 4.
404 citations
TL;DR: An artificial neural network technique together with a feature extraction technique, viz., the wavelet transform, for the classification of EEG signals, which provides a potentially powerful technique for preprocessing EEG signals prior to classification.
291 citations
Proceedings Article•
27 Jul 1997TL;DR: The convergence of the backpropagation (BP) algorithm is investigated, and it is found that the optimal solution is typically not found, and networks larger than might be expected can result in lower training and generalization error.
Abstract: For many reasons, neural networks have become very popular AI machine learning models. Two of the most important aspects of machine learning models are how well the model generalizes to unseen data, and how well the model scales with problem complexity. Using a controlled task with known optimal training error, we investigate the convergence of the backpropagation (BP) algorithm. We find that the optimal solution is typically not found. Furthermore, we observe that networks larger than might be expected can result in lower training and generalization error. This result is supported by another real world example. We further investigate the training behavior by analyzing the weights in trained networks (excess degrees of freedom are seen to do little harm and to aid convergence), and contrasting the interpolation characteristics of multi-layer perceptron neural networks (MLPs) and polynomial models. (overfitting behavior is very different - the MLP is often biased towards smoother solutions). Finally, we analyze relevant theory outlining the reasons for significant practical differences. These results bring into question common beliefs about neural network training regarding convergence and optimal network size, suggest alternate guidelines for practical use (lower fear of excess degrees of freedom), and help to direct future work (e.g. methods for creation of more parsimonious solutions, importance of the MLP/BP bias and possibly worse performance of "improved" training algorithms).
256 citations
TL;DR: This article examined the relationship between a company's initial motivation for seeking certification (QCert) and its perception of the benefits it has received; and, second, the impact of time on perceptions of benefits received.
Abstract: Utilizes a survey of 272 Australian ISO 9002 quality certified companies to examine two issues: first, the relationship between a company’s initial motivation for seeking certification (QCert) and its perception of the benefits it has received; and, second, the impact of time on perceptions of benefits received. Companies which sought QCert because of an externally‐imposed perception of the necessity to “obtain a certificate” were found to experience fewer beneficial outcomes of QCert, in comparison with companies which sought QCert because of an internally‐driven desire to improve organizational performance. Additionally, no evidence was found that longer‐certified companies experience more benefits than recently‐certified companies, regardless of the initial motivation for seeking QCert. Cautions against the drive towards “forcing” companies to seek QCert as a result of a perception of an external threat. Such a process appears to be counterproductive.
230 citations
TL;DR: A quantitative method of resolving the problem of confound measurement of each discrete phasic SCR as well as the tonic skin conductance level (SCL) using a modelling technique that takes advantage of the stereotyped nature of the within-subject SCR waveform is reported.
218 citations
TL;DR: In this article, the authors review the theoretical and empirical work that has been conducted in relation to virtual communities in society, using it as a basis for an integrative three phase Virtual Communities in Society model, including variables that affect individuals' decision to join virtual communities, variables that explain how members of virtual communities affect their immediate environment, and variables that describe how virtual communities are transforming society.
192 citations
TL;DR: In this paper, the impact of vegetation on channel form and velocity can be quantified in much the same way that other broadly based hydraulic geometry relations have been developed, and the results obtained in this study, combined with those from other regions, permit an interpretation of the sensitivity of channel width to different forms of channel vegetation, information of use for river management.
176 citations
TL;DR: Research suggests that the adoption of a medium block spacing is preferred, with front and rear knee angles in the set position approximating 90 and 130°, respectively, with the hips held moderately high, to develop a high force rate combined with a high maximum force.
Abstract: Many variables have been studied pertaining to the block sprint start. Research suggests that the adoption of a medium block spacing is preferred, with front and rear knee angles in the set position approximating 90 and 130 degrees, respectively, with the hips held moderately high. The sprinter must be capable of developing a high force rate combined with a high maximum force, especially in the horizontal direction. This ability to create high force underlies other important indicators of starting performance such as minimum block clearance time, maximum block leaving velocity and maximum block leaving acceleration. Once the sprinter has projected him/herself from the blocks at a low angle (40 to 45 degrees) relative to the ground, the following 2 post-block steps should occur with the total body centre of gravity ahead of the contacting foot at foot strike to minimise potential horizontal braking forces.
169 citations
TL;DR: In this paper, a planar relaxation of polystyrene was found in the first 1 and 10 nm from the free surface, whereas the dominant relaxation was normal to the surface.
Abstract: Near-edge X-ray absorption fine structure, NEXAFS, spectroscopy was used to investigate the relaxations of polystyrene, a typical amorphous polymer, near a free surface after the imposition of a small deformation. Using synchrotron radiation, the NEXAFS dichroic ratio was determined for both the Auger and total electron yield processes as a function of temperature to determine the orientation of the polymer in the first 1 and 10 nm from the free surface, respectively. Complete relaxation of the polymer was not seen for temperatures less than the bulk glass transition temperature. No evidence of enhanced mobility at the free surface was found. A planar relaxation of the polymer was found in the first nanometer from the free surface, whereas in the first 10 nm, the dominant relaxation was normal to the surface.
146 citations
TL;DR: Preliminary data indicate that the concentration of sLRP is altered in the plasma of patients with liver disease, which may antagonize the clearance of ligands by cell bound LRP perturbing diverse processes including lipid metabolism, cell migration and extracellular proteinase activity.
TL;DR: Results suggest that the conditions proposed by I.C. Biederman and P. Gerhardstein are not generally applicable, the recognition of qualitatively distinct objects often relies on viewpoint-dependent mechanisms, and the molar features of view-based mechanisms appear to be image features rather than geons.
Abstract: Based on the geon structural description approach, I. Biederman and P.C. Gerhardstein (1993) proposed 3 conditions under which object recognition is predicted to be viewpoint invariant. Two experiments are reported that satisfied all 3 criteria yet revealed performance that was clearly viewpoint dependent. Experiment 1 demonstrated that for both sequential matching and naming tasks, recognition of qualitatively distinct objects became progressively longer and less accurate as the viewpoint difference between study and test viewpoints increased. Experiment 2 demonstrated that for single-part objects, larger effects of viewpoint occurred when there was a change in the visible structure, indicating sensitivity to qualitative features in the image, not geon structural descriptions. These results suggest that the conditions proposed by I. Biederman and P.C. Gerhardstein are not generally applicable, the recognition of qualitatively distinct objects often relies on viewpoint-dependent mechanisms, and the molar features of view-based mechanisms appear to be image features rather than geons. Language: en
Book•
28 Oct 1997TL;DR: The first major textbook to encompass the true complexity of climate change is as discussed by the authors, where the authors present the processes that drive the Earth's present climate system, including human-induced and natural components forcing climate change.
Abstract: This is the first major textbook to encompass the true complexity of climate change. Whilst 'greenhouse' warming dominates most of the literature, Ted Bryant presents numerous reasons for the observed climate change of the past century. He argues that changes in climate, more dramatic than those of the last 150 years, have been a predominant aspect of the Earth's climate over the past two million years. Bryant highlights human impacts on climate other than 'greenhouse' gases, including sulphate air pollutants, dust and urban heat islands. He also explains the natural components forcing climate change.Bryant presents, in simple terms, the processes that drive the Earth's present climate system. He outlines the nature and reasons for temperature fluctuations over millennia, including recent human-induced climate change. Finally, he discusses the impact of climate change upon human health and the world's ecosystems.
TL;DR: The structural and activity data are consistent with caerin 1.1 interacting with membranes in a similar manner to other antimicrobial peptides, i.e. via a carpet-like mechanism whereby the individual peptides aggregate in a helical manner and orient themselves parallel to the membrane in a sheet-like arrangement.
Abstract: Caerin 1.1 is one of the major antimicrobial peptides isolated from the skin of the Australian green tree frog, Litoria splendida. Two-dimensional 1H-1H and 1H-13C NMR spectroscopy in trifluoroethanol/ H2O (50:50, by vol.) have been used to assign the 1H and 13C-NMR spectra of this 25-amino-acid peptide. From an examination of these data, and using distance geometry and molecular dynamics calculations, the solution conformation of caerin 1.1 has been determined. The peptide adopts two well-defined helices from Leu2 to Lys11 and from Val17 to His24 separated by a region of less-defined helicity and greater flexibility. Overall, the peptide has a distinct amphipathic charge distribution. The solution structure of caerin 1.1 is compared with activity data against a variety of micro-organisms for the parent peptide and some naturally occurring and synthetic variants of caerin 1.1. The structural and activity data are consistent with caerin 1.1 interacting with membranes in a similar manner to other antimicrobial peptides, i.e. via a carpet-like mechanism whereby the individual peptides aggregate in a helical manner and orient themselves parallel to the membrane in a sheet-like arrangement [Shai, Y. (1995) Trends Biochem. Sci. 20, 460–464].
TL;DR: Regression analyses indicated that participants' approach and avoidance coping responses varied across four sport-related stressful situations, lending credence to the interactional (contextual) model of coping in which participants' use of coping strategies is at least a partial function of situational demands.
Abstract: The purpose of this study was to examine links between coping style, situational appraisals and the subsequent use of coping strategies in response to acute stress among competitive Australian basketball players (N = 190, 93 men and 97 women, ranging in age from 18 to 44 years). Regression analyses indicated that participants' approach and avoidance coping responses varied across four sport-related stressful situations. In addition, both personal and situational factors accounted for significant variation in players' approach coping responses, with situational factors better predictors of approach coping than personal dispositions. For avoidance coping, situational appraisals (i.e. perceived stress and controllability) were again better predictors than personal dispositions. The results lend credence to the interactional (contextual) model of coping in which participants' use of coping strategies is at least a partial function of situational demands.
TL;DR: The most detailed studies of quartzose karst landforms have been in present-day tropical regions, or areas believed to have been tropical in the geologically recent past as mentioned in this paper.
TL;DR: In this article, the authors evaluated the exercise capacity of individuals with mild to moderate Parkinson's disease and determined whether abnormalities in respiratory function and gait affect exercise capacity, using a maximum exercise test on a cycle ergometer and respiratory function tests and a walking test.
TL;DR: The Family Attitude Scale (FAS) as discussed by the authorsAS is a 30-item instrument that can be completed by any informant and is associated with reported anger, anger expression and anxiety of respondents.
Abstract: Research on outcomes from psychiatric disorders has highlighted the importance of expressed emotion (EE), but its cost-effective measurement remains a challenge. This article describes development of the Family Attitude Scale (FAS), a 30-item instrument that can be completed by any informant. Its psychometric characteristics are reported in parents of undergraduate students and in 70 families with a schizophrenic member. The total FAS had high internal consistency in all samples, and reports of angry behaviour in FAS items showed acceptable inter-rater agreement. The FAS was associated with the reported anger, anger expression and anxiety of respondents. Substantial associations between the parents' FAS and the anger and anger expression of students was also observed. Parents of schizophrenic patients had higher FAS scores than parents of students, and the FAS was higher if disorder duration was longer or patient functioning was poorer. Hostility, high criticism and low warmth on the Camberwell Family Interview (CFI) were associated with a more negative FAS. The highest FAS in the family was a good predictor of a highly critical environment on the CFI. The FAS is a reliable and valid indicator of relationship stress and expressed anger that has wide applicability.
TL;DR: A pronounced fall in serum leptin in association with reduced carbohydrate intake before substantial loss of body fat suggests a role for leptin in defending the body's carbohydrate stores and implicates leptin in the satiating effects of carbohydrate.
Abstract: The response of serum leptin to short (4 days) and prolonged (28 days) energy restriction (50 % reduction in energy intake) was determined in 18 (9 male, 9 female) moderately obese humans (body mass index 32.0 ± 0.6 kg/m2 mean ± SEM), 9 of whom had mild non-insulin-dependent diabetes mellitus (NIDDM). Body composition was assessed before and at the end of the energy restriction using DEXA. The subjects lost a measured 2.6 ± 0.4 kg of body fat after 28 days and an estimated 0.3 kg at 4 days. Serum leptin fell to 64 ± 3 % of baseline levels at day 4 and further to 46 ± 4 % at day 28. In a multiple correlation analysis, the change in leptin concentration at day 4 was significantly related to the change in dietary carbohydrate intake (partial r = 0.68, p < 0.005) but not to changes in fat (r = 0.12) or protein (r = 0.02) intakes. There was a 1 : 1 relationship between the changes in leptin and dietary carbohydrate (regression slope = 1.0 ± 0.3). Gender, or the presence of NIDDM had no effects on these responses. This pronounced fall in serum leptin in association with reduced carbohydrate intake before substantial loss of body fat suggests a role for leptin in defending the body's carbohydrate stores and implicates leptin in the satiating effects of carbohydrate. Dietary or other interventions which maintain leptin levels during weight reduction may lead to improvements in weight loss. [Diabetologia (1997) 40: 348–351]
TL;DR: A growing number of Muslim countries are expressing the desire, and in some cases taking serious actions, to turn to Islamic laws and teachings (shariah) in modelling their way of life, including their economic behaviour as discussed by the authors.
Abstract: A growing number of Muslim countries are expressing the desire, and in some cases taking serious actions, to turn to Islamic laws and teachings (shariah) in modelling their way of life, including their economic behaviour. Attempts to investigate the consequences of applying Islamic principles in Muslim societies. Argues that the traditional tools of economic analysis suggest that Islamic societies are likely to face many problems if they free their economies completely from all traces of interest, impose the religious tax of Zakat in a strict fashion and abandon all kinds of speculation.
TL;DR: In this paper, the authors explore the methodological approaches to accounting research and practice and what has been termed the critical accounting movement, and the debates over the concept of rationality in critical accounting research.
TL;DR: It is shown that all the existing RNN architecture can be considered as special cases of the general RNN architectures, and how these existing architectures can be transformed to the generalRNN architectures.
TL;DR: In this article, the authors used logit, probit and discriminant analysis to test for structural differences between the financial characteristics of interest-free banks and conventional banks and found that the two groups of banks may be differentiated in terms of liquidity, leverage, and credit risk, but not in the terms of profitability and efficiency.
Abstract: Uses logit, probit and discriminant analysis to test for structural differences between the financial characteristics of interest‐free banks and conventional banks. The analysis extends to various financial dimensions which evaluate performance, namely: liquidity, leverage, credit risk, profitability and efficiency. Covers 15 interest‐free banks and 15 conventional banks. The statistical evidence suggests that the two groups of banks may be differentiated in terms of liquidity, leverage and credit risk, but not in terms of profitability and efficiency.
TL;DR: This correspondence studies resilient functions which have applications in fault-tolerant distributed computing, quantum cryptographic key distribution, and random sequence generation for stream ciphers and presents a number of new methods for synthesizing resilient functions.
Abstract: This correspondence studies resilient functions which have applications in fault-tolerant distributed computing, quantum cryptographic key distribution, and random sequence generation for stream ciphers. We present a number of new methods for synthesizing resilient functions. An interesting aspect of these methods is that they are applicable both to linear and nonlinear resilient functions. Our second major contribution is to show that every linear resilient function can be transformed into a large number of nonlinear resilient functions with the same parameters. As a result, we obtain resilient functions that are highly nonlinear and have a high algebraic degree.
TL;DR: This article examined how these contexts may be very different for girls as compared to boys in single sex as well as co-educational physical education lessons and found that the meanings expressed through teachers' choices in language are different for both genders.
Abstract: With the ‘linguistic turn’ in contemporary social theory there has been an increased interest in looking more closely at pedagogical practices in physical education as they construct social relations. Initially, and within a rather different theoretical framework this took the form of counting the number and kind of interactions teachers had with boys as compared to girls. More recently researchers have begun to look closely at how language choices construct relations of power between teacher and students and produce contexts for learning. This paper examines how these contexts may be very different for girls as compared to boys in single sex as well as co‐educational physical education lessons. Systemic functional linguistics and semiotic theory have provided the methodology and analytical tools to make visible the system of meanings expressed through teachers choices in language. The analysis has been further informed by the work of post‐structuralist and particularly feminist post‐structuralis...
TL;DR: Genetic variation among populations, expressed as the standardised variance in allele frequencies (FST), was inversely related to expected larval dispersal capability, implying that for species which undergo direct development, local populations are effectively closed and evolve largely independent of one another.
Abstract: In south-eastern Australia, the prosobranch gastropods Morula marginalba (Blainville), Cominella lineolata (Lamarck) and Bedeva hanleyi (Angas) have similar fine-scale distributions, but appear to possess very different dispersal capabilities due to contrasting modes of larval development. M.marginalba produce planktonic larvae, whereas C. lineolata and B. hanleyi undergo direct development in benthic egg capsules and emerge as crawling juveniles. To test for possible effects of contrasting life histories on levels of genetic variation within and among populations, a survey was conducted of allozyme variation at six polymorphic loci in 8 to 9 local populations of each species. Collections of snails were made between June 1992 and November 1993. Sampling ranges spanned between 162 and 180 km of coast. Regardless of larval type, proportions of single-locus genotypes in each collection were consistent with the recruitment of offspring which had been generated through random mating. However, genotypic diversity was lower in those species that undergo direct development. Loci surveyed in C. lineolata and B. hanleyi were polymorphic (i.e. frequency of most common allele <95%) in fewer populations than those examined for M.␣marginalba (P <0.001) and, where polymorphisms occurred, also possessed significantly fewer alleles (P <0.001). Consequently, average levels of expected heterozygosity were greater in populations of M. marginalba than in those of either of the other species (P <0.001). Genetic variation among populations, expressed as the standardised variance in allele frequencies (FST), was inversely related to expected larval dispersal capability. The nine collections of M. marginalba showed little overall differentiation (FST = 0.017; P <0.001), reflecting the ability of planktonic larvae to interconnect local populations, and so limit divergence due to drift and natural selection. In contrast, there were high levels of allelic heterogeneity among the nine collections of C. lineolata (FST = 0.523; P <0.001) and eight collections of B. hanleyi (FST = 0.140; P <0.001). These data imply that for species which undergo direct development, local populations are effectively closed and evolve largely independent of one another.
TL;DR: In this paper, the conformational state of a protein when it forms a high molecular weight complex with α-crystallin is investigated by examining, using NMR spectroscopy and size exclusion high performance liquid chromatography, the interaction of α-stallin with α lactalbumin and its various intermediately folded (molten globule) states.
TL;DR: In this paper, a combination of SHRIMP U-Pb dating of single zircon grains and specially constructed expected ZIRcon-age histograms was used to determine provenance or protosource areas for sediment samples.
TL;DR: In this paper, the authors investigated possible factors that are associated with experiencing acute stress in police work and found that years of experience as a police officer influenced the extent of the officers' beliefs that they could cope with stressful events.
Abstract: Two studies investigated possible factors that are associated with experiencing acute stress in police work. Occupational acute stressors in law enforcement were identified by police officers in Study 1 (N = 39). Using standardized mean (Z) scores as the dependent variable, MANOVA indicated that four of the 17 acute stressors identified in Study 1 were significantly different than the remaining stressors in terms of their combined intensity and frequency. The purpose of Study 2 was to examine the intensity of primary and secondary appraisal and reappraisal of police officers (N = 95) related to these previously identified stressful events, and the extent to which these measures differed as a function of experience in the police force. An adapted version of the Stress Appraisal Measure (SAM) measured police officers' primary appraisals, secondary appraisals, reappraisals, and overall stress perceptions that were associated with these four acute stressors. Multiple regression analyses indicated that two primary appraisal dimensions, threat and challenge, were significant predictors of overall stressfulness, with centrality found as an important appraisal dimension. MANOVA revealed that years of experience as a police officer influenced the extent of the officers' beliefs that they could cope with stressful events.
TL;DR: Skeletal muscle fibre type composition is different in infants and adults and there is an age-dependent increase in Type 2b fibres over the lifespan, which supports a gene-environment interaction on fibretype composition in human skeletal muscle.
Abstract: Muscle fibre type composition in infant and adult populations and relationships with obesity