Showing papers by "University of South Australia published in 1997"

Fatigue, alcohol and performance impairment

Abstract: Reduced opportunity for sleep and reduced sleep quality are frequently related to accidents involving shift-workers1,2,3 Poor-quality sleep and inadequate recovery leads to increased fatigue, decreased alertness and impaired performance in a variety of cognitive psychomotor tests4 However, the risks associated with fatigue are not well quantified Here we equate the performance impairment caused by fatigue with that due to alcohol intoxication, and show that moderate levels of fatigue produce higher levels of impairment than the proscribed level of alcohol intoxication

Focus on Qualitative Methods Qualitative Metasynthesis: Issues and Techniques

Abstract: There has been an accumulation of qualitative studies in recent years, but little cumulation of the understandings gained from them. Qualitative research appears endangered both by efforts to synthesize studies and by the failure to do so. Techniques used have included reciprocal translations of key metaphors and concepts and qualitative and quantitative comparative analyses to produce narrative and theoretical integrations. The major problem yet to be resolved is developing usable and communicable systematic approaches to conducting metasynthesis projects that maintain the integrity of individual studies.

Salivary melatonin as a circadian phase marker: validation and comparison to plasma melatonin

Abstract: There are many situations in which it would be useful to know the phase state of the biological clock. It is recognized that measurement of melatonin levels can provide this information, but traditionally blood has been used for the analysis, and there are many problems in extending the measurements into the home or field situations. The aim of this study was to develop and validate a salivary melatonin radioimmunoassay and to compare results obtained against a plasma assay for determining the onset of melatonin secretion. The assay developed was sensitive (4.3 pM) and required only 200 microliters of sample. A rhythm in melatonin was detected in saliva, peaking at approximately 120 pM or 30% of the plasma levels. Using an objective criterion for determining the onset of secretion (mean +/- 2 standard deviations of three daytime samples), the time of onset was shown to exhibit low intraindividual variability (coefficient of variation = 1.5%-4.3%). The time of onset determined using saliva was significantly correlated with the plasma onset (r = .70, p < .05). The onsets determined were 22:30 h +/- 22 min for the saliva and 21:50 h +/- 16 min for plasma for 17 subjects. Similarly, the acrophases of the saliva and plasma melatonin rhythms were significantly correlated. Neither posture alone nor changes in posture affected the calculation of the onset of melatonin secretion using the saliva approach. Very high saliva flow rates induced by citric acid resulted in lower melatonin concentrations compared to the gentle chewing on parafin film. These results firmly establish the use of salivary melatonin measurements for phase typing of the melatonin rhythm in humans.

H ∞ -control for Markovian jumping linear systems with parametric uncertainty

Abstract: This paper studies the problem of H∞-control for linear systems with Markovian jumping parameters The jumping parameters considered here are two separable continuous-time, discrete-state Markov processes, one appearing in the system matrices and one appearing in the control variable Our attention is focused on the design of linear state feedback controllers such that both stochastic stability and a prescribed H∞-performance are achieved We also deal with the robust H∞-control problem for linear systems with both Markovian jumping parameters and parameter uncertainties The parameter uncertainties are assumed to be real, time-varying, norm-bounded, appearing in the state matrix Both the finite-horizon and infinite-horizon cases are analyzed We show that the control problems for linear Markovian jumping systems with and without parameter uncertainties can be solved in terms of the solutions to a set of coupled differential Riccati equations for the finite-horizon case or algebraic Riccati equations for the infinite-horizon case Particularly, robust H∞-controllers are also designed when the jumping rates have parameter uncertainties

The Consensus Glossary of Temporal Database Concepts - February 1998 Version.

Abstract: This document1 contains definitions of a wide range of concepts specific to and widely used within temporal databases. In addition to providing definitions, the document also includes explanations of concepts as well as discussions of the adopted names.

Outcomes 5 years post traumatic brain injury (with further reference to neurophysical impairment and disability)

Abstract: The assessment of recovery and outcomes post-traumatic brain injury (TBI) has often been poorly researched and reported in past literature. Indeed, an accurate documentation of outcomes in this population had never been performed in the state of South Australia. To redress this situation this study collected data on people who had sustained a TBI 5 years previously, using medical records, personal interview/questionnaire and neurophysical assessment in order to investigate broad outcomes as well as the specific nature and prevalence of any residual physical impairment and disability. The results (n = 67) indicate that the subjects' living arrangements had not altered significantly, and nearly half had returned to some form of paid work, though over 50% were reliant on the welfare system. The majority (57%) felt they had improved in all areas, 19% partially improved and 8% felt they had actually deteriorated. Considering the physical data, the most frequent areas of residual impairment were headaches, followed by balance difficulties and fatigue/weakness. Functionally, 30% had some degree of deficit in upper limb activity and 9% required assistance for particular transfer tasks. Overall balance was impaired in 34% and gait was altered in 24% with 9% reliant on wheelchairs for mobility. Such data may be used in the education of people with TBI and those who live and/or work with them, as well as in future studies assessing the impact of various factors on recovery and outcomes. Evidence was also provided that residual physical issues should be considered along with the more researched areas of cognition and psychosocial issues.

A very large integrated pH-ISFET sensor array chip compatible with standard CMOS processes

Abstract: The development and preliminary evaluation of a very large pH-sensitive ISFET sensor array chip is reported in this paper. The sensor array chip boasts a 15×16 array of pH-ISFETs with on-chip control and readout circuits. It was designed and fabricated using a novel process which is compatible with standard CMOS technology. This process only required four new mask layers in the design stage and four extra standard processing steps in the fabrication stage. A novel signal processing technique was also employed.

On the optimization of machining parameters for milling operations

Abstract: Owing to the significant role that machining parameters play in performing successful and efficient machining operations, determination of the best or optimum machining parameters is still the subject of many studies. The need to use optimum machining parameters to improve machining efficiency is of greater importance when NC machines with high capital cost are employed. This paper describes development and utilization of an optimization system which determines optimum machining parameters for milling operations. These parameters are intended for use by NC machines, however, they can also be used by conventional machines. The paper discusses both single-tool and multi-tool milling operations where emphasis has been placed on the latter. An example has been presented at the end of the paper to give a clear picture from the application of the system and its efficiency.

The role of xenobiotic metabolizing enzymes in arylamine toxicity and carcinogenesis: Functional and localization studies

Abstract: In both animal models and humans, the first and obligatory step in the activation of arylamines is N-hydroxylation. This pathway is primarily mediated by the phase-I enzymes CYP1A1, CYP1A2 and CYP4B1. In the presence of flavonoids such as alpha-naphthoflavone and flavone, both CYP3A4 and CYP3A5 have also been shown to play a minor role in the activation of food-derived heterocyclic amines. The further activation of N-hydroxyarylamines by phase-II metabolism can involve both N,O-acetylation and N,O-sulfonation catalyzed by N-acetyltransferases (NAT1 and NAT2) and sulfotransferases, respectively. Using an array of techniques, we have been unable to detect constitutive CYP1A expression in any segments of the human gastrointestinal tract. This is in contrast to the rabbit where CYP1A1 protein was readily detectable on immunoblots in microsomes prepared from the small intestine. In humans, CYP3A3/3A4 expression was detectable in the esophagus and all segments of the small intestine. Northern blot analysis of eleven human colons showed considerable heterogeneity in CYP3A mRNA between individuals, with the presence of two mRNA species in same subjects. Employing the technique of hybridization histochemistry (also known as in situ hybridization), CYP4B1 expression was observed in some human colons but not in the liver or the small intestine. Hybridization histochemistry studies have also demonstrated variable NAT1 and NAT2 expression in the human gastrointestinal tract. NAT1 and NAT2 mRNA expression was detected in the human liver, small intestine, colon, esophagus, bladder, ureter, stomach and lung. Using a general aryl sulfotransferase riboprobe (HAST1), we have demonstrated marked sulfotransferase expression in the human colon, small intestine, lung, stomach and liver. These studies demonstrate that considerable variability exists in the expression of enzymes involved in the activation of aromatic amines in human tissues. The significance of these results in relation to a role for heterocyclic amines in colon cancer is discussed.

Why doctors leave rural practice.

Abstract: Retention of rural doctors remains difficult because of complex factors that influence decisions of medical families. This study explores the reasons why Queensland rural doctors left their communities during 1995. Semi-structured interviews were conducted with contactable former rural doctors who claimed that they had entered rural practice with the intention to stay for a substantial period of time. The interviews were audiotaped, transcribed and analysed using NUD.IST software. Participants appeared to be subject to a dynamic balance between opposing pressures to stay and pressures to leave. In time, they became susceptible to 'triggers' to leave. These triggers were sometimes locality-specific and could be difficult to address, particularly without early intervention. We believe that it should be possible to develop strategies that address specific concerns of rural doctors, particularly if they are identified early. The optimum period of stay in rural practice should be reconsidered, such that moderate stays should be rewarded in a way that retains the doctors in some form of rural, or near-rural practice.

Attitudes and beliefs about bullying among Australian school children

Abstract: Attitudes and beliefs of Australian schoolchildren about bullying in schools were assessed and related to age, gender and reported involvement in bullying others at school. Questionnaires were answered anonymously by 2940 boys and 2508 girls attending 20 South Australian coeducational schools; student ages ranged from 9 to 18 years. The questionnaires contained the following reliable multi-item measures: attitudes toward bullying; normative pressure experienced by students to bully others at school; attitudes to victims of bullying; perceived capacity to bully others; and proneness to bully others at school. Generally, the mean scores on the attitudelbelief measures showed similar age trends to those indicating engagement in bullying behaviour. With increasing age, up to about 16 years, both boys and girls reported more engagement in persistent bullying and displayed attitudes and beliefs more supportive of bullying. Beyond 16 years, however, both attitudes and behaviours moderated, as reflected in result...

The relationship between occupational balance and health: a pilot study

Abstract: Occupational therapists, physicians and others evince an appreciation of the relationship between balanced lifestyles and health, but there are few studies that concentrate on balance as a key issue. This paper reports on a pilot study that tested the effectiveness of a questionnaire to explore perceptions of occupational balance and its relationship to health. The ultimate aim is to provide information that may assist clients, or the population in general, about potentially healthily balanced configurations of occupation. Using a cluster sampling method and with 146 respondents the results of a questionnaire indicated that, for many of these respondents, perceived ideal occupational balance is approximately equal involvement in physical, mental, social and rest occupations. A correlation between reported good health and the closeness of current occupational patterns to the ideal was statistically significant. These promising results warrant further investigation. Copyright © 1997 Whurr Publishers Ltd.

Reduced performance of male and female athletes at 580 m altitude.

Abstract: This study examined the effect of mild hypobaria (MH) on the peak oxygen consumption ( O2peak) and performance of ten trained male athletes [ (SEM); O2peak = 72.4 (2.2) ml · kg−1 · min−1] and ten trained female athletes [ O2peak = 60.8 (2.1) ml · kg−1 · min−1]. Subjects performed 5-min maximal work tests on a cycle ergometer within a hypobaric chamber at both normobaria (N, 99.33 kPa) and at MH (92.66 kPa), using a counter-balanced design. MH was equivalent to 580 m altitude. O2peak at MH decreased significantly compared with N in both men [− 5.9 (0.9)%] and women [− 3.7 (1.0)%]. Performance (total kJ) at MH was also reduced significantly in men [− 3.6 (0.8)%] and women [− 3.8 (1.2)%]. Arterial oxyhaemoglobin saturation (SaO2) at O2peak was significantly lower at MH compared with N in both men [90.1 (0.6)% versus 92.0 (0.6)%] and women [89.7 (3.1)% versus 92.1 (3.0)%]. While SaO2 at O2peak was not different between men and women, it was concluded that relative, rather than absolute, O2peak may be a more appropriate predictor of exercise-induced hypoxaemia. For men and women, it was calculated that 67–76% of the decrease in O2peak could be accounted for by a decrease in O2 delivery, which indicates that reduced O2 tension at mild altitude (580 m) leads to impairment of exercise performance in a maximal work bout lasting ≈ 5 min.

Reviewing Foucault:: possibilities and problems for nursing and health care

Abstract: This paper addresses Foucauldian theory and its usefulness to nursing research. It is written in the form of a discussion between the authors on the merits and liabilities of Foucauldian theory as applied to analyses of nursing. As such, it focuses upon some of the more pertinent critiques of both Foucauldian and postmodern theory. By addressing Foucault from two different positions, the discussion seeks to demonstrate the complexity of Foucauldian theory and warns against over-simplification in its application to nursing research. The authors also argue for an awareness of the strengths and weaknesses of any given theoretical stance.