Ocular refractive and biometric characteristics in patients with tilted disc syndrome

Purpose: To evaluate the ocular refractive and biometric characteristics in patients with tilted disc syndrome (TDS). Methods: This case-control study comprised 41 eyes of 25 patients with established TDS and forty eyes of 20 age- and sex-matched healthy control subjects. All had a complete ocular examination including refraction and analysis using Fourier transformation, slit lamp biomicroscopy, pachymetry keratometry, and ocular biometry. Corneal topography examinations were performed in the syndrome group only. Results: There were no significant differences in spherical equivalent (p = 0.334) and total astigmatism (p= 0.246) between groups. However, mean best spectacular corrected visual acuity was significantly worse in TDS patients (P < 0.001). The lenticular astigmatism was significantly greater in the syndrome group, while the corneal component was greater in the controls (p = 0.004 and p = 0.002, respectively). The measured biometric features were the same in both groups, except for the lens thickness, relative lens position, and lens-axial length factor which were greater in the TDS group (p = 0.002, p = 0.015, and p = 0.025, respectively). Conclusions: Clinically significant lenticular astigmatism, more oblique corneal astigmatism, and thicker lens were characteristic findings in patients with TDS.

Applying an equity lens to tobacco-control policies and their uptake in six western-european countries

We identified policies that may be effective in reducing smoking among socioeconomically disadvantaged groups, and examined trends in their level of application between 1985 and 2000 in six western-European countries (Sweden, Finland, the United Kingdom, the Netherlands, Germany, and Spain). We located studies from literature searches in major databases, and acquired policy data from international data banks and questionnaires distributed to tobacco policy organisations/researchers. Advertising bans, smoking bans in workplaces, removing barriers to smoking cessation therapies, and increasing the cost of cigarettes have the potential to reduce socioeconomic inequalities in smoking. Between 1985 and 2000, tobacco control policies in most countries have become more targeted to decrease the smoking behaviour of low-socioeconomic groups. Despite this, many national tobacco-control strategies in western-European countries still fall short of a comprehensive policy approach to addressing smoking inequalities.

Near real-time prediction of Zenith Tropospheric Delays for position estimation over long-baseline CORS network

This paper presents the preliminary results in establishing a strategy for predicting Zenith Tropospheric Delay (ZTD) and relative ZTD (rZTD) between Continuous Operating Reference Stations (CORS) in near real-time. It is anticipated that the predicted ZTD or rZTD can assist the network-based Real-Time Kinematic (RTK) performance over long inter-station distances, ultimately, enabling a cost effective method of delivering precise positioning services to sparsely populated regional areas, such as Queensland. This research firstly investigates two ZTD solutions: 1) the post-processed IGS ZTD solution and 2) the near Real-Time ZTD solution. The near Real-Time solution is obtained through the GNSS processing software package (Bernese) that has been deployed for this project. The predictability of the near Real-Time Bernese solution is analyzed and compared to the post-processed IGS solution where it acts as the benchmark solution. The predictability analyses were conducted with various prediction time of 15, 30, 45, and 60 minutes to determine the error with respect to timeliness. The predictability of ZTD and relative ZTD is determined (or characterized) by using the previously estimated ZTD as the predicted ZTD of current epoch. This research has shown that both the ZTD and relative ZTD predicted errors are random in nature; the STD grows from a few millimeters to sub-centimeters while the predicted delay interval ranges from 15 to 60 minutes. Additionally, the RZTD predictability shows very little dependency on the length of tested baselines of up to 1000 kilometers. Finally, the comparison of near Real-Time Bernese solution with IGS solution has shown a slight degradation in the prediction accuracy. The less accurate NRT solution has an STD error of 1cm within the delay of 50 minutes. However, some larger errors of up to 10cm are observed.

Place value, multiplicativity, reunitizing and effective classroom teaching of decimal numeration

Student understanding of decimal number is poor (e.g., Baturo, 1998; Behr, Harel, Post & Lesh, 1992). This paper reports on a study which set out to determine the cognitive complexities inherent in decimal-number numeration and what teaching experiences need to be provided in order to facilitate an understanding of decimal-number numeration. The study gave rise to a theoretical model which incorporated three levels of knowledge. Interview tasks were developed from the model to probe 45 students’ understanding of these levels, and intervention episodes undertaken to help students construct the baseline knowledge of position and order (Level 1 knowledge) and an understanding of multiplicative structure (Level 3 knowledge). This paper describes the two interventions and reports on the results which suggest that helping students construct appropriate mental models is an efficient and effective teaching strategy.

Contact lens correction of presbyopia

The ageing population highlights the need to provide effective optical solutions for presbyopic contact lens wearers. However, data gathered from annual contact lens fitting surveys demonstrate that fewer than 40% of contact lens wearers over 45 years of age (virtually all of whom can be presumed to suffer a partial or complete loss of accommodation) are prescribed a presbyopic correction. Furthermore, monovision is prescribed as frequently as multifocal lenses. These observations suggest that an optimal solution to the contact lens correction of presbyopia remains elusive.

A study of water binding, mobility and dehydration in contact lens hydrogels using NMR

Hydrogel polymers are used for the manufacture of soft (or disposable) contact lenses worldwide today, but have a tendency to dehydrate on the eye. In vitro methods that can probe the potential for a given hydrogel polymer to dehydrate in vivo are much sought after. Nuclear magnetic resonance (NMR) has been shown to be effective in characterising water mobility and binding in similar systems (Barbieri, Quaglia et al., 1998, Larsen, Huff et al., 1990, Peschier, Bouwstra et al., 1993), predominantly through measurement of the spin-lattice relaxation time (T1), the spinspin relaxation time (T2) and the water diffusion coefficient (D). The aim of this work was to use NMR to quantify the molecular behaviour of water in a series of commercially available contact lens hydrogels, and relate these measurements to the binding and mobility of the water, and ultimately the potential for the hydrogel to dehydrate. As a preliminary study, in vitro evaporation rates were measured for a set of commercial contact lens hydrogels. Following this, comprehensive measurement of the temperature and water content dependencies of T1, T2 and D was performed for a series of commercial hydrogels that spanned the spectrum of equilibrium water content (EWC) and common compositions of contact lenses that are manufactured today. To quantify material differences, the data were then modelled based on theory that had been used for similar systems in the literature (Walker, Balmer et al., 1989, Hills, Takacs et al., 1989). The differences were related to differences in water binding and mobility. The evaporative results suggested that the EWC of the material was important in determining a material's potential to dehydrate in this way. Similarly, the NMR water self-diffusion coefficient was also found to be largely (if not wholly) determined by the WC. A specific binding model confirmed that the we was the dominant factor in determining the diffusive behaviour, but also suggested that subtle differences existed between the materials used, based on their equilibrium we (EWC). However, an alternative modified free volume model suggested that only the current water content of the material was important in determining the diffusive behaviour, and not the equilibrium water content. It was shown that T2 relaxation was dominated by chemical exchange between water and exchangeable polymer protons for materials that contained exchangeable polymer protons. The data was analysed using a proton exchange model, and the results were again reasonably correlated with EWC. Specifically, it was found that the average water mobility increased with increasing EWe approaching that of free water. The T1 relaxation was also shown to be reasonably well described by the same model. The main conclusion that can be drawn from this work is that the hydrogel EWe is an important parameter, which largely determines the behaviour of water in the gel. Higher EWe results in a hydrogel with water that behaves more like bulk water on average, or is less strongly 'bound' on average, compared with a lower EWe material. Based on the set of materials used, significant differences due to composition (for materials of the same or similar water content) could not be found. Similar studies could be used in the future to highlight hydrogels that deviate significantly from this 'average' behaviour, and may therefore have the least/greatest potential to dehydrate on the eye.

Infant wrapping as an evidence-based strategy to encourage settling and the utilisation of the supine sleep position

Objective: To identify knowledge, attitudes and practices of child health nurses relating to infant wrapping as an effective settling/sleep strategy. Methods: A pre-test/post-test intervention design was used to explore knowledge, attitudes and practices relating to wrapping in a sample of child health nurses (n=182): a) pre-test survey; b) educational intervention incorporating evidence relating to infant wrapping; SIDS&KIDS endorsed infant wrapping pamphlet; Safe Sleeping recommendations. Emphasis was placed on infant wrapping as an effective settling strategy for parents to use as an alternative to prone positioning; c) post-test survey to evaluate intervention effectiveness. Results: Pretest results identified wide variation in nurses’ knowledge, attitudes and practices of infant wrapping as a settling/sleep strategy. The intervention increased awareness of wrapping guidelines and self-reported practices relating to parent advice. Significant positive changes in nurses’ awareness of wrapping guidelines (p<0.001); to wrap in supine position only (p<0.001); and parental advice to use wrapping as an alternative strategy to prone positioning to assist settling/sleep (p<0.01), were achieved post-test. Conclusions: Managing unsettled infants and promoting safe sleeping practices are issues routinely addressed by child health nurses working with parents of young infants. Queensland has a high incidence of prone sleeping. Infant wrapping is an evidence-based strategy to improve settling and promote supine sleep consistent with public health recommendations. Infant wrapping guidelines are now included in Queensland Health’s state policy and Australian SIDSandKids information relating to safe infant sleeping. In communicating complex health messages to parents, health professionals have a key role in reinforcing safe sleeping recommendations and offering safe, effective settling/sleep strategies to address the non-recommended use of prone positioning for unsettled infants.

Best practice for prevention and treatment of cardiovascular disease through an equity lens : a review

Background: Despite declining rates of cardiovascular disease (CVD) mortality in developed countries, lower socioeconomic groups continue to experience a greater burden of the disease. There are now many evidence-based treatments and prevention strategies for the management of CVD and it is essential that their impact on the more disadvantaged group is understood if socioeconomic inequalities in CVD are to be reduced. Aims: To determine whether key interventions for CVD prevention and treatment are effective among lower socioeconomic groups, to describe barriers to their effectiveness and the potential or actual impact of these interventions on the socioeconomic gradient in CVD. Methods: Interventions were selected from four stages of the CVD continuum. These included smoking reduction strategies, absolute risk assessment, cardiac rehabilitation, secondary prevention medications, and heart failure self-management programmes. Electronic searches were conducted using terms for each intervention combined with terms for socioeconomic status (SES). Results: Only limited evidence was found for the effectiveness of the selected interventions among lower SES groups and there was little exploration of socioeconomic-related barriers to their uptake. Some broad themes and key messages were identified. In the majority of findings examined, it was clear that the underlying material, social and environmental factors associated with disadvantage are a significant barrier to the effectiveness of interventions. Conclusion: Opportunities to reduce socioeconomic inequalities occur at all stages of the CVD continuum. Despite this, current treatment and prevention strategies may be contributing to the widening socioeconomic-CVD gradient. Further research into the impact of best-practice interventions for CVD upon lower SES groups is required.

Destination competitiveness through the lens of brand positioning : the case of Australia’s Sunshine Coast

The purpose of the paper is to provide a collaborative practitioner/academic interpretation of a destination’s competitiveness through the lens of brand positioning in the domestic short break drive market. A 173 item questionnaire, which was mailed to a systematic random sample of 3000 households in the target market, attracted a 17% useable response. The paper compares how one destination, the Sunshine Coast, is positioned in its most important market, in relation to the brand identity intended by the destination marketing organisation (DMO). Key constructs were brand salience, brand associations and brand resonance. The Sunshine Coast was found to hold a leadership position in the minds of consumers, and the results indicated a strong level of congruence between actual market perceptions and the brand identity intended by the DMO. There were strong associations between brand salience, brand associations and brand resonance. The findings provided the destination of interest with both a measure of past marketing effectiveness as well as positive indicators of future performance. The paper represents collaboration between a tourism practitioner and a tourism academic, and attempts a contribution to the emerging literature on destination competitiveness through the lens of positioning theory.

Ocular surface changes with short-term contact lens wear

Contact lenses are a common method for the correction of refractive errors of the eye. While there have been significant advancements in contact lens designs and materials over the past few decades, the lenses still represent a foreign object in the ocular environment and may lead to physiological as well as mechanical effects on the eye. When contact lenses are placed in the eye, the ocular anatomical structures behind and in front of the lenses are directly affected. This thesis presents a series of experiments that investigate the mechanical and physiological effects of the short-term use of contact lenses on anterior and posterior corneal topography, corneal thickness, the eyelids, tarsal conjunctiva and tear film surface quality. The experimental paradigm used in these studies was a repeated measures, cross-over study design where subjects wore various types of contact lenses on different days and the lenses were varied in one or more key parameters (e.g. material or design). Both, old and newer lens materials were investigated, soft and rigid lenses were used, high and low oxygen permeability materials were tested, toric and spherical lens designs were examined, high and low powers and small and large diameter lenses were used in the studies. To establish the natural variability in the ocular measurements used in the studies, each experiment also contained at least one “baseline” day where an identical measurement protocol was followed, with no contact lenses worn. In this way, changes associated with contact lens wear were considered in relation to those changes that occurred naturally during the 8 hour period of the experiment. In the first study, the regional distribution and magnitude of change in corneal thickness and topography was investigated in the anterior and posterior cornea after short-term use of soft contact lenses in 12 young adults using the Pentacam. Four different types of contact lenses (Silicone hydrogel/ Spherical/–3D, Silicone Hydrogel/Spherical/–7D, Silicone Hydrogel/Toric/–3D and HEMA/Toric/–3D) of different materials, designs and powers were worn for 8 hours each, on 4 different days. The natural diurnal changes in corneal thickness and curvature were measured on two separate days before any contact lens wear. Significant diurnal changes in corneal thickness and curvature within the duration of the study were observed and these were taken into consideration for calculating the contact lens induced corneal changes. Corneal thickness changed significantly with lens wear and the greatest corneal swelling was seen with the hydrogel (HEMA) toric lens with a noticeable regional swelling of the cornea beneath the stabilization zones, the thickest regions of the lenses. The anterior corneal surface generally showed a slight flattening with lens wear. All contact lenses resulted in central posterior corneal steepening, which correlated with the relative degree of corneal swelling. The corneal swelling induced by the silicone hydrogel contact lenses was typically less than the natural diurnal thinning of the cornea over this same period (i.e. net thinning). This highlights why it is important to consider the natural diurnal variations in corneal thickness observed from morning to afternoon to accurately interpret contact lens induced corneal swelling. In the second experiment, the relative influence of lenses of different rigidity (polymethyl methacrylate – PMMA, rigid gas permeable – RGP and silicone hydrogel – SiHy) and diameters (9.5, 10.5 and 14.0) on corneal thickness, topography, refractive power and wavefront error were investigated. Four different types of contact lenses (PMMA/9.5, RGP/9.5, RGP/10.5, SiHy/14.0), were worn by 14 young healthy adults for a period of 8 hours on 4 different days. There was a clear association between fluorescein fitting pattern characteristics (i.e. regions of minimum clearance in the fluorescein pattern) and the resulting corneal shape changes. PMMA lenses resulted in significant corneal swelling (more in the centre than periphery) along with anterior corneal steepening and posterior flattening. RGP lenses, on the other hand, caused less corneal swelling (more in the periphery than centre) along with opposite effects on corneal curvature, anterior corneal flattening and posterior steepening. RGP lenses also resulted in a clinically and statistically significant decrease in corneal refractive power (ranging from 0.99 to 0.01 D), large enough to affect vision and require adjustment in the lens power. Wavefront analysis also showed a significant increase in higher order aberrations after PMMA lens wear, which may partly explain previous reports of "spectacle blur" following PMMA lens wear. We further explored corneal curvature, thickness and refractive changes with back surface toric and spherical RGP lenses in a group of 6 subjects with toric corneas. The lenses were worn for 8 hours and measurements were taken before and after lens wear, as in previous experiments. Both lens types caused anterior corneal flattening and a decrease in corneal refractive power but the changes were greater with the spherical lens. The spherical lens also caused a significant decrease in WTR astigmatism (WRT astigmatism defined as major axis within 30 degrees of horizontal). Both the lenses caused slight posterior corneal steepening and corneal swelling, with a greater effect in the periphery compared to the central cornea. Eyelid position, lid-wiper and tarsal conjunctival staining were also measured in Experiment 2 after short-term use of the rigid and SiHy contact lenses. Digital photos of the external eyes were captured for lid position analysis. The lid-wiper region of the marginal conjunctiva was stained using fluorescein and lissamine green dyes and digital photos were graded by an independent masked observer. A grading scale was developed in order to describe the tarsal conjunctival staining. A significant decrease in the palpebral aperture height (blepharoptosis) was found after wearing of PMMA/9.5 and RGP/10.5 lenses. All three rigid contact lenses caused a significant increase in lid-wiper and tarsal staining after 8 hours of lens wear. There was also a significant diurnal increase in tarsal staining, even without contact lens wear. These findings highlight the need for better contact lens edge design to minimise the interactions between the lid and contact lens edge during blinking and more lubricious contact lens surfaces to reduce ocular surface micro-trauma due to friction and for. Tear film surface quality (TFSQ) was measured using a high-speed videokeratoscopy technique in Experiment 2. TFSQ was worse with all the lenses compared to baseline (PMMA/9.5, RGP/9.5, RGP/10.5, and SiHy/14) in the afternoon (after 8 hours) during normal and suppressed blinking conditions. The reduction in TFSQ was similar with all the contact lenses used, irrespective of their material and diameter. An unusual pattern of change in TFSQ in suppressed blinking conditions was also found. The TFSQ with contact lens was found to decrease until a certain time after which it improved to a value even better than the bare eye. This is likely to be due to the tear film drying completely over the surface of the contact lenses. The findings of this study also show that there is still a scope for improvement in contact lens materials in terms of better wettability and hydrophilicity in order to improve TFSQ and patient comfort. These experiments showed that a variety of changes can occur in the anterior eye as a result of the short-term use of a range of commonly used contact lens types. The greatest corneal changes occurred with lenses manufactured from older HEMA and PMMA lens materials, whereas modern SiHy and rigid gas permeable materials caused more subtle changes in corneal shape and thickness. All lenses caused signs of micro-trauma to the eyelid wiper and palpebral conjunctiva, although rigid lenses appeared to cause more significant changes. Tear film surface quality was also significantly reduced with all types of contact lenses. These short-term changes in the anterior eye are potential markers for further long term changes and the relative differences between lens types that we have identified provide an indication of areas of contact lens design and manufacture that warrant further development.

Investigating effective wayfinding in airports : a Bayesian network approach

Effective Wayfinding is the successful interplay of human and environmental factors resulting in a person successfully moving from their current position to a desired location in a timely manner. To date this process has not been modelled to reflect this interplay. This paper proposes a complex modelling system approach of wayfinding by using Bayesian Networks to model this process, and applies the model to airports. The model suggests that human factors have a greater impact on effective wayfinding in airports than environmental factors. The greatest influences on human factors are found to be the level of spatial anxiety experienced by travellers and their cognitive and spatial skills. The model also predicted that the navigation pathway that a traveller must traverse has a larger impact on the effectiveness of an airport’s environment in promoting effective wayfinding than the terminal design.

A Flight control scheme to improve position tracking performance of rotary-wing UASs

This paper outlines an innovative and feasible flight control scheme for a rotary-wing unmanned aerial system (RUAS) with guaranteed safety and reliable flight quality in a gusty environment. The proposed control methodology aims to increase gust-attenuation capability of a RUAS to ensure improved flight performance when strong gusts occur. Based on the design of an effective estimator, an altitude controller is firstly constructed to synchronously compensate for fluctuations of the main rotor thrust which might lead to crashes in a gusty environment. Afterwards, a nonlinear state feedback controller is proposed to stabilize horizontal positions of the RUAS with gust-attenuation property. Performance of the proposed control framework is evaluated using parameters of a Vario XLC helicopter and high-fidelity simulations show that the proposed controllers can effectively reduce side-effect of gusts and demonstrate performance improvement when compared with the proportional-integral-derivative (PID) controllers.

Monocular vision based autonomous navigation for a cost-effective MAV in GPS-denied environments

In this paper, we present a monocular vision based autonomous navigation system for Micro Aerial Vehicles (MAVs) in GPS-denied environments. The major drawback of monocular systems is that the depth scale of the scene can not be determined without prior knowledge or other sensors. To address this problem, we minimize a cost function consisting of a drift-free altitude measurement and up-to-scale position estimate obtained using the visual sensor. We evaluate the scale estimator, state estimator and controller performance by comparing with ground truth data acquired using a motion capture system. All resources including source code, tutorial documentation and system models are available online.

Building distributed leadership for effective supervision of creative practice higher research degrees : final report 2014

Building distributed leadership for effective supervision of creative practice higher research degrees is an Office for Learning and Teaching (OLT) funded project, conducted in partnership between Queensland University of Technology, The University of Melbourne, Auckland University of Technology, University of New South Wales and University of Western Sydney. The project was initiated to develop a cooperative approach to establishing an understanding of the contextual frameworks of the emergent field of creative practice higher degrees by research (HDRs); capturing early insights of administrators and supervisors; gathering exemplars of good practices; and establishing an in-common understanding of effective approaches to supervision. To this end, the project has produced: • A literature review, to provide a research foundation for creative practice higher research degree supervision (Chapter 3). • A contextual review of disciplinary frameworks for HDR programs, produced through surveys of postgraduate research administrators (Section 4.1), and an analysis of institutional materials and academic development programs for supervisors (Section 4.2). • A National Symposium, Effective Supervision of Creative Arts Research Degrees (ESCARD), at QUT in Brisbane in February 2013, with 62 delegates from 20 Australasian Universities, at which project findings were disseminated, and delegates presented case studies and position papers, and participated in discussions on key issues for supervisors (Appendix 1). • Resources, including a booklet for supervisors: 12 Principles for the Effective Supervision of Creative Practice Higher Research Degrees, which encapsulates attitudes, insights and good practices of experienced and new supervisors. It was produced through a content analysis of interviews with twenty-five supervisors in creative disciplines (visual and performing arts, music, new media, creative writing and design) (Printed booklet, PDF, Appendix 3). • A project website to disseminate project outcomes , which holds project findings, relevant references, and a repository of case studies and position papers by supervisors and program administrators. • A call for papers for a special issue ‘Supervising Practice: Perspectives on the Supervision of Creative Practice Research Higher Degrees’ of ACCESS Journal: Critical Perspectives on Communication, Cultural & Policy Studies (ERA ranked A quality) in 2014 (Appendix 2). • A community of supervisory practice initiated through project partnerships, a national symposium where supervisors from across Australasia met in dialogue for the first time, resource sharing, and joint publishing opportunities. • A set of recommendations for supervision capacity building and academic development, produced through the triangulation of literature and contextual reviews, analysis of institutional frameworks, interviews with supervisors and national dialogues. It is anticipated that the project’s outcomes will support experienced and new supervisors in this emergent field, and so benefit HDR students, and will enable creative disciplines to build supervision capacity, and so to accommodate growth in postgraduate enrolments. Funded as a pilot project, the project set out to establish a robust research base to provide a foundation for future work involving sharing good practices, resource building, and designing effective approaches to academic development for supervisors. Recommendations that were produced out of this project include the need to extend beyond generic, formal training for supervisors to academic development that harnesses and extends distributed leadership; focuses on local, disciplinary contexts; has a strong emphasis on case studies; provides diverse resources; and facilitates dialogue between supervisors. Recommendations also include developing frameworks for mentoring new supervisors and building a national network to facilitate cross-institutional discourse, disseminate good practices, and share insights into the management of risk factors, ethical issues, and preparing candidates for examination. As a pilot investigation, the outcomes of this project lay the ground for this future work.

Influence of stop position on spectacle magnification

Purpose To develop and use equations of spectacle magnification when the limiting stop is either the entrance pupil of the eye or an artificial pupil in front of a lens. Methods Spectacle magnification was determined for ophthalmic lenses in air and for water environments. The reference was the retinal image for an uncorrected eye in air with a natural pupil. Results When an artificial pupil is placed in front of lenses, spectacle magnification is hardly affected by lens power, unlike the usual situation where the natural pupil is used. The water environment provides interesting influences in which spectacle magnification is highly sensitive to the distance between the cornea and eye entrance pupil. In water, retinal images are approximately 18% bigger than in air. Wearing air-filled goggles in water increases retinal image size by about 13% compared with that when they are not worn. Conclusions The equations extend earlier understanding of spectacle magnification and should be useful for those wishing to determine magnification of ophthalmic lens systems when artificial pupils and environments such as water are used.