45 research outputs found

    Vegetation studies in the eastern goldfields of Western Australia with particular reference to their role in geological reconnaissance and mineral exploration

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    Within the Eastern Goldfields vegetation studies have revealed that distinct associations characterise the different geological units. The relationship may be constant within a given field area but species differences may occur on similar rock types in different areas of the region. The physical and chemical environments are both influential in the establishment of geobotanical relationships; a vegetation association developed over an outcropping rock unit may vary from that growing on the similar unit when soil covered. Similarly, any marked changes occurring in the chemistry of the soil over differing rock types may be revealed by modifications in the plant assemblage. Thus, an increase in the soil metal content over the normal background content may affect the vegetation supported. Soil geochemical anomalies over areas of mineralisation of nickel, copper and arsenic (gold) are not always characterised by recognisable geobotanical relations: where possible relationships are observable, as over part of the Jimberlana Dyke at Norseman, and over a limited area at Kambalda, further work is necessary in similar localities of the region to substantiate them. Biogeochemical analyses may usefully indicate areas where the concentration of metals in the soils becomes anomalous, thus indicating the location of potential mineralisation. The application of the bio-geochemical method may be limited by the non-availability of elements for plant absorption.<p

    The Heavy Vehicle Study: a case-control study investigating risk factors for crash in long distance heavy vehicle drivers in Australia

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    Background Heavy vehicle transportation continues to grow internationally; yet crash rates are high, and the risk of injury and death extends to all road users. The work environment for the heavy vehicle driver poses many challenges; conditions such as scheduling and payment are proposed risk factors for crash, yet the precise measure of these needs quantifying. Other risk factors such as sleep disorders including obstructive sleep apnoea have been shown to increase crash risk in motor vehicle drivers however the risk of heavy vehicle crash from this and related health conditions needs detailed investigation. Methods and Design The proposed case control study will recruit 1034 long distance heavy vehicle drivers: 517 who have crashed and 517 who have not. All participants will be interviewed at length, regarding their driving and crash history, typical workloads, scheduling and payment, trip history over several days, sleep patterns, health, and substance use. All participants will have administered a nasal flow monitor for the detection of obstructive sleep apnoea. Discussion Significant attention has been paid to the enforcement of legislation aiming to deter problems such as excess loading, speeding and substance use; however, there is inconclusive evidence as to the direction and strength of associations of many other postulated risk factors for heavy vehicle crashes. The influence of factors such as remuneration and scheduling on crash risk is unclear; so too the association between sleep apnoea and the risk of heavy vehicle driver crash. Contributory factors such as sleep quality and quantity, body mass and health status will be investigated. Quantifying the measure of effect of these factors on the heavy vehicle driver will inform policy development that aims toward safer driving practices and reduction in heavy vehicle crash; protecting the lives of many on the road network

    Does an on-road motorcycle coaching program reduce crashes in novice riders? A randomised control trial

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    OBJECTIVES: Motorcycle riding is increasing globally and confers a high risk of crash-related injury and death. There is community demand for investment in rider training programs but no high-quality evidence about its effectiveness in preventing crashes. This randomised trial of an on-road rider coaching program aimed to determine its effectiveness in reducing crashes in novice motorcycle riders. METHODS: Between May 2010 and October 2012, 2399 newly-licensed provisional riders were recruited in Victoria, Australia and completed a telephone interview before randomisation to intervention or control groups. Riders in the intervention group were offered an on-road motorcycle rider coaching program which involved pre-program activities, 4h riding and facilitated discussion in small groups with a riding coach. Outcome measures were collected for all participants via telephone interviews at 3 and 12 months after program delivery (or equivalent for controls), and via linkage to police-recorded crash and offence data. The primary outcome was a composite measure of police-recorded and self-reported crashes; secondary outcomes included traffic offences, near crashes, riding exposure, and riding behaviours and motivations. RESULTS: Follow-up was 89% at 3 months and 88% at 12 months; 60% of the intervention group completed the program. Intention-to-treat analyses conducted in 2014 indicated no effect on crash risk at 3 months (adjusted OR 0.90, 95% CI: 0.65-1.27) or 12 months (adjusted OR 1.00, 95% CI: 0.78-1.29). Riders in the intervention group reported increased riding exposure, speeding behaviours and rider confidence. CONCLUSIONS: There was no evidence that this on-road motorcycle rider coaching program reduced the risk of crash, and we found an increase in crash-related risk factors

    Reproducibility of adenosine stress cardiovascular magnetic resonance in multi-vessel symptomatic coronary artery disease

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    <p>Abstract</p> <p>Purpose</p> <p>First-pass perfusion cardiovascular magnetic resonance (CMR) is increasingly being utilized in both clinical practice and research. However, the reproducibility of this technique remains incompletely evaluated, particularly in patients with severe coronary artery disease (CAD). The purpose of this study was to determine the inter-study reproducibility of adenosine stress CMR in patients with symptomatic multi-vessel CAD and those at low risk for CAD.</p> <p>Methods</p> <p>Twenty patients (10 with CAD, 10 low risk CAD) underwent two CMR scans 8 ± 2 days apart. Basal, mid and apical left ventricular short axis slices were acquired using gadolinium 0.05 mmol/kg at peak stress (adenosine, 140 μ/kg/min, 4 min) and rest. Myocardial perfusion was evaluated qualitatively by assessing the number of ischemic segments, and semi-quantitatively by determining the myocardial perfusion reserve index (MPRi) using a normalized upslope method. Inter-study and observer reproducibility were assessed--the latter being defined by the coefficient of variation (CoV), which was calculated from the standard deviation of the differences of the measurements, divided by the mean. Additionally, the percentage of myocardial segments with perfect agreement and inter- and intra-observer MPRi correlation between studies, were also determined.</p> <p>Results</p> <p>The CoV for the number of ischemic segments was 31% with a mean difference of -0.15 ± 0.88 segments and 91% perfect agreement between studies. MPRi was lower in patients with CAD (1.13 ± 0.21) compared to those with low risk CAD (1.59 ± 0.58), p = 0.02. The reproducibility of MPRi was 19% with no significant difference between patients with CAD and those with low risk CAD (p = 0.850). Observer reproducibility for MPRi was high: inter-observer CoV 9%, r = 0.93 and intra-observer CoV 5%, r = 0.94. For trials using perfusion CMR as an endpoint, an estimated sample size of 12 subjects would be required to detect a two-segment change in the number of ischemic segments (power 0.9, α 0.05).</p> <p>Conclusions</p> <p>Adenosine stress CMR, by qualitative and semi-quantitative normalized upslope analyses are reproducible techniques in both patients with multi-vessel CAD and those without known CAD. The robust inter-study reproducibility of perfusion CMR supports its clinical and research application.</p

    The Heavy Vehicle Study: a case-control study investigating risk factors for crash in long distance heavy vehicle drivers in Australia

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    Background Heavy vehicle transportation continues to grow internationally; yet crash rates are high, and the risk of injury and death extends to all road users. The work environment for the heavy vehicle driver poses many challenges; conditions such as scheduling and payment are proposed risk factors for crash, yet the precise measure of these needs quantifying. Other risk factors such as sleep disorders including obstructive sleep apnoea have been shown to increase crash risk in motor vehicle drivers however the risk of heavy vehicle crash from this and related health conditions needs detailed investigation. Methods and Design The proposed case control study will recruit 1034 long distance heavy vehicle drivers: 517 who have crashed and 517 who have not. All participants will be interviewed at length, regarding their driving and crash history, typical workloads, scheduling and payment, trip history over several days, sleep patterns, health, and substance use. All participants will have administered a nasal flow monitor for the detection of obstructive sleep apnoea. Discussion Significant attention has been paid to the enforcement of legislation aiming to deter problems such as excess loading, speeding and substance use; however, there is inconclusive evidence as to the direction and strength of associations of many other postulated risk factors for heavy vehicle crashes. The influence of factors such as remuneration and scheduling on crash risk is unclear; so too the association between sleep apnoea and the risk of heavy vehicle driver crash. Contributory factors such as sleep quality and quantity, body mass and health status will be investigated. Quantifying the measure of effect of these factors on the heavy vehicle driver will inform policy development that aims toward safer driving practices and reduction in heavy vehicle crash; protecting the lives of many on the road network

    Severe obstructive sleep apnea and long distance truck driving : a case report

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    Introduction: Untreated sleep disorders can increase driver crash risk by up to 7 fold, and truck drivers have a variety of risk factors for sleep disorders. Measures currently used to identify drivers at risk depend predominantly on the ability of the driver to identify and report themselves as sleepy. Methods: This case report presents a 54 year old long distance truck driver who participated in a case-control study, underwent at home breathing monitoring and was followed up with an in-depth interview. Results: Self-reported measures did not identify this driver as at risk of sleepiness or sleep apnea; yet he was subsequently diagnosed with severe sleep apnea using an at home monitor and polysomnography. Conclusions: Self-assessment of risk factors is insufficient as a screen for sleep apnea. General practitioners are in an ideal position to identify potential sleep apnea sufferers and can initiate the enquiry process that leads to diagnostic testing.5 page(s

    The Use of self-report exposure measures among novice motorcyclists : appropriateness and best practice recommendations

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    Objectives: While self-report methods to collect exposure information have large practical advantages in many research contexts, little research has specifically investigated the reliability and validity of motorcyclists' self-reported exposure. The present study aimed to examine the reliability and validity of different self-report exposure measures and to provide recommendations on best practice self-report riding exposure questions. Methods: The reliability and validity of different self-report exposure measures were examined amongst novice motorcyclists through t-tests, Bland Altman plots, coefficients of variation, and correlations. Results: The most valid and reliable data was provided when riding exposure was asked for the current average week rather than earlier and longer periods, and in units of time rather than distance or number of trips. The greater reliability of riding exposure found amongst commuting and rural riders compared to recreational and metropolitan riders respectively and at the second interview compared to the first suggests that factors such as riding purposes, geographical locations, and riding experience can contribute to measurement error. Conclusions: If self-reported odometer readings are used, questions on whether the respondents share their own bike or ride more than one bike, and a built-in process to ensure respondents report the exact odometer reading on their bike are recommended. It is recommended that self-report riding exposure questions ask about the hours of riding for the current average week, and data on riding purposes, locations, and experience are also collected.10 page(s
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