The penetrance and characteristics of contact lens wear in Australia

Background A population-based, cross-sectional telephone survey was conducted to estimate the penetrance and characteristics of contact lens wear in Australia. Methods Based on postcode distribution, 42,749 households around Australia were randomly selected from the national electronic telephone directory. During calls, the number of individuals and contact lens wearers in each household aged between 15 and 64 years was ascertained. Contact lens wearers were interviewed using a structured questionnaire, to determine details of demographics, lens type, mode of lens wear and hygienic habits. Contact lens wear characteristics and habits were compared by lens type and mode of use. Results Of the 32,405 households contacted, 19,171 (59.2 per cent) agreed to participate. The penetrance of contact lens wear during the study period was 5.01 per cent (95% CI: 4.78-5.24). The mean age of lens wearers was 36.5 ± 18.3 years and 63.4 per cent were female. There were significant differences in the habits and characteristics of lens wearers depending on their lens type and mode of use. Conclusions The penetrance of contact lens wear concurs with market estimates and equates to approximately 680,000 contact lens wearers aged between 15 and 64 years in Australia. This is the most detailed and extensive population-based survey of contact lens wearers ever conducted. The discrepancies found between the characteristics of lens wearers surveyed in this study compared to those in previous studies of contact lens practitioners highlights the importance of study design. These results may be applied to other regions with similar health-care and regulatory systems.

Experimental and numerical characteristics of portable water-filled road safety barrier system under different impact conditions

This research has developed an innovative road safety barrier system that will enhance roadside safety. In doing so, the research developed new knowledge in the field of road crash mitigation for high speed vehicle impact involving plastic road safety barriers. This road safety barrier system has the required feature to redirecting an errant vehicle with limited lateral displacement. Research was carried out using dynamic computer simulation technique support by experimental testing. Future road safety barrier designers may use the information in this research as a design guideline to improve the performance and redirectional capability of the road safety barrier system. This will lead to better safety conditions on the roadways and potentially save lives.

Characteristics of ultrafine particle sources and deposition rates in primary school classrooms

The aim of this work was to investigate changes in particle number concentration (PNC) within naturally ventilated primary school classrooms arising from local sources either within or adjacent to the classrooms. We quantify the rate at which ultrafine particles were emitted either from printing, grilling, heating or cleaning activities and the rate at which the particles were removed by both deposition and air exchange processes. At each of 25 schools in Brisbane, Australia, two weeks of measurements of PNC and CO2 were taken both outdoors and in the two classrooms. Bayesian regression modelling was employed in order to estimate the relevant rates and analyse the relationship between air exchange rate (AER), particle infiltration and the deposition rates of particle generated from indoor activities in the classrooms. During schooling hours, grilling events at the school tuckshop as well as heating and printing in the classrooms led to indoor PNCs being elevated by a factor of more than four, with emission rates of (2.51 ± 0.25) x 1011 p min-1, (8.99 ± 6.70) x 1011 p min-1 and (5.17 ± 2.00) x 1011 p min-1, respectively. During non-school hours, cleaning events elevated indoor PNC by a factor of above five, with an average emission rate of (2.09 ± 6.30) x 1011 p min-1. Particles were removed by both air exchange and deposition; chiefly by ventilation when AER > 0.7 h-1 and by deposition when AER < 0.7 h-1.

Measuring the preference for dwelling characteristics of Melbourne : railway stations and house prices

The relationship between public transportation and home values has proven to be complex, with studies providing divergent findings. Using Victorian Valuer General Data for 2009, this paper applies a hedonic pricing approach to the Melbourne metropolitan housing market in order to estimate the impacts of proximity to a train station on residential property prices. The findings reveal a negative impact on dwelling price for those properties within 125 metres from a train station and a positive relationship between dwelling price and proximity for properties more than 125 metres away.

Characteristics of epoxy resin/SiO2 nanocomposite insulation : effects of plasma surface treatment on the nanoparticles

The present study compares the effects of two different material processing techniques on modifying hydrophilic SiO2 nanoparticles. In one method, the nanoparticles undergo plasma treatment by using a custom-developed atmospheric-pressure non-equilibrium plasma reactor. With the other method, they undergo chemical treatment which grafts silane groups onto their surface and turns them into hydrophobic. The treated nanoparticles are then used to synthesize epoxy resin-based nanocomposites for electrical insulation applications. Their characteristics are investigated and compared with the pure epoxy resin and nanocomposite fabricated with unmodified nanofillers counterparts. The dispersion features of the nanoparticles in the epoxy resin matrix are examined through scanning electron microscopy (SEM) images. All samples show evidence that the agglomerations are smaller than 30 nm in their diameters. This indicates good dispersion uniformity. The Weibull plot of breakdown strength and the recorded partial discharge (PD) events of the epoxy resin/plasma-treated hydrophilic SiO2 nanocomposite (ER/PTI) suggest that the plasma-treated specimen yields higher breakdown strength and lower PD magnitude as compared to the untreated ones. In contrast, surprisingly, lower breakdown strength is found for the nanocomposite made by the chemically treated hydrophobic particles, whereas the PD magnitude and PD numbers remain at a similar level as the plasma-treated ones.

Microstructure and electromagnetic characteristics of Ni nanoparticle film coated carbon microcoils

Carbon microcoils (CMCs) have been coated with a Ni nanoparticle film using an electroless plating process. The morphology, the elemental composition and the phases in the coating layer, complex permittivity and permeability of the CMCs and Ni-coated CMCs were, respectively, investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and microwave vector network analysis at room temperature. A homogeneous dispersion of Ni nanoparticles on the outer surface of the CMCs was obtained, with a mean particle size of ∼34.4 nm and the phosphorus content of about 8.5 wt%. When comparing the coated and uncoated CMC samples, the real (ε′) and imaginary (ε″) part of the complex permittivity as well as dielectric dissipation factor (tgδε = ε″/ε′) of the Ni-coated CMCs were much smaller, while the real (μ′) and imaginary (μ″) part of the complex permeability and the magnetic dissipation factor (t g σμ = μ″ / μ′) were larger. The enhanced microwave absorption of Ni-coated CMCs resulted from stronger dielectric and magnetic losses. In contrast, the microwave absorption of uncoated CMCs was mainly attributed to the dielectric rather than magnetic losses.

Dispersion characteristics of a cylindrical antenna in magnetoactive plasma

Dispersion characteristics and topography of electromagnetic fields of axially symmetric surface waves (SW) and of azimuth surface waves (ASW) propagating in a structure composed of a cylindrical metal antenna and magnetoactive plasma are investigated. The antenna and plasma may be separated by a vacuum layer. The dispersion characteristics of SW and ASW are presented as functions of the antenna and the magnetoactive plasma parameters. Close agreement between theory and experimental results are shown. Surface impedances of the SW and ASW are calculated for various parameters of the problem.

Characteristics of high-performance ambipolar organic field-effect transistors based on a diketopyrrolopyrrole-benzothiadiazole copolymer

In this paper, we report the device characteristics of ambipolar thin-film transistors (TFTs) based on a diketopyrrolopyrrole-benzothiadiazole copolymer. This polymer semiconductor exhibits the largest comparable electron and hole mobility values in a single organic semiconductor. The key to realizing such high mobility values, which are $0.5&cm}{2}/\hbox{V}̇\hbox{s, is molecular design, i.e., the use of suitable surface treatments of the source/drain contact electrodes and device architectures, particularly top-gate configurations. The subthreshold characteristics of the TFT devices are greatly improved by the use of dual-gate device geometry. We also report the first measurement of the velocity distribution of electron and hole velocities in an ambipolar organic semiconductor.

Electrical characteristics of lateral heterostructure organic field-effect bipolar transistors

We describe and discuss the unique electrical characteristics of an organic field-effect transistor in which the active layer consists of a type II lateral heterojunction located approximately midway between the source and drain. The two active semiconductors on either side of the junction transport only one carrier type each, with the other becoming trapped, which leads to devices that operate in only the steady state when there is balanced electron and hole injections from the drain and source. We describe the unique transfer characteristics of such devices in two material systems.

Characteristics of low-speed vehicle run-over events in children : an 11-year review

Objectives: The purpose of this study was to investigate the characteristics associated with fatal and non-fatal low-speed vehicle run-over (LSVRO) events in relation to person, incident and injury characteristics, in order to identify appropriate points for intervention and injury prevention. Methods: Data on all known LSVRO events in Queensland, Australia, over 11 calendar years (1999–2009) were extracted from five different databases representing the continuum of care ( prehospital to fatality) and manually linked. Descriptive and multivariate analyses were used to analyse the sample characteristics in relation to demographics, health service usage, outcomes, incident characteristics, and injury characteristics. Results: Of the 1641 LSVRO incidents, 98.4% (n=1615) were non-fatal, and 1.6% were fatal (n=26). Over half the children required admission to hospital (56%, n=921); mean length of stay was 3.4 days. Younger children aged 0–4 years were more frequently injured, and experienced more serious injuries with worse outcomes. Patterns of injury (injury type and severity), injury characteristics (eg, time of injury, vehicle type, driver of vehicle, incident location), and demographic characteristics (such as socioeconomic status, indigenous status, remoteness), varied according to age group. Almost half (45.6%; n=737) the events occurred outside major cities, and approximately 10% of events involved indigenous children. Parents were most commonly the vehicle drivers in fatal incidents. While larger vehicles such as four-wheel drives (4WD) were most frequently involved in LSVRO events resulting in fatalities, cars were most frequently involved in non-fatal events. Conclusions: This is the first study, to the authors’ knowledge, to analyse the characteristics of fatal and non-fatal LSVRO events in children aged 0–15 years on a state-wide basis. Characteristics of LSVRO events varied with age, thus age-specific interventions are required. Children living outside major cities, and indigenous children, were over-represented in these data. Further research is required to identify the burden of injury in these groups.

Constraints and characteristics of flexible work arrangements in small not-for-profit firms

There is a great deal of research that examines flexible working arrangements, but this work tends to be concentrated in large organisations. This research examines the approach taken to flexible working arrangements in five small community based, not for profit organisations. We present three propositions that aim to understand the constraints and the characteristics of flexible work in this rarely studied sector.