Lee Gordon-Brown

Simulation studies of age-specific lifetime major depression prevalence

BackgroundThe lifetime prevalence (LTP) of Major Depressive Disorder (MDD) is the proportion of a population having met criteria for MDD during their life up to the time of assessment. Expectation holds that LTP should increase with age, but this has not usually been observed. Instead, LTP typically increases in the teenage years and twenties, stabilizes in adulthood and then begins to decline in middle age. Proposed explanations for this pattern include: a cohort effect (increasing incidence in more recent birth cohorts), recall failure and/or differential mortality. Declining age-specific incidence may also play a role.MethodsWe used a simulation model to explore patterns of incidence, recall and mortality in relation to the observed pattern of LTP. Lifetime prevalence estimates from the 2002 Canadian Community Health Survey, Mental Health and Wellbeing (CCHS 1.2) were used for model validation and calibration.ResultsIncidence rates predicting realistic values for LTP in the 15-24 year age group (where mortality is unlikely to substantially influence prevalence) lead to excessive LTP later in life, given reasonable assumptions about mortality and recall failure. This suggests that (in the absence of cohort effects) incidence rates decline with age. Differential mortality may make a contribution to the prevalence pattern, but only in older age categories. Cohort effects can explain the observed pattern, but only if recent birth cohorts have a much higher (approximately 10-fold greater) risk and if incidence has increased with successive birth cohorts over the past 60-70 years.ConclusionsThe pattern of lifetime prevalence observed in cross-sectional epidemiologic studies seems most plausibly explained by incidence that declines with age and where some respondents fail to recall past episodes. A cohort effect is not a necessary interpretation of the observed pattern of age-specific lifetime prevalence.

Geographical Information Systems in Victorian Secondary Schools: Current Constraints and Opportunities.

Whilst widespread diffusion and adoption of spatial enabling technology, such as geographic information systems (GIS), is taking place within Australian public and private sectors, the same cannot be said for GIS within Australian secondary schools and state-based geography curricula. In the Australian state of Victoria, information regarding the status of GIS diffusion within secondary-school geography departments is currently limited, and in this setting, its adoption and use is recognised as relying upon the individual drive of committed geography teachers and schools, rather than any policy innovation. This paper reports the findings of a survey regarding the current state of GIS-based geography education in Victorian secondary schools, which was administered to Victorian secondary geography teachers via an anonymous online survey instrument during 2008. Results show that there are many barriers and constraints affecting adoption and use of GIS for geography teaching and learning in Victorian secondary schools. They include “bottom-up” resistance that might be overcome by GIS-based geography teacher training and “top-down” failure to support GIS-based education in secondary geography curriculum. In recognition of policy documents and statements by lead agencies in favour of GIS-based geography curriculum in Australian and Victorian secondary schools (including documentation relating to a proposed National Geography Curriculum), the survey results reported here can be regarded as important baseline information prerequisite to consensus-building regarding the place of GIS-based geography teaching and learning.

Flood-tide Delta Morphological Change at the Gippsland Lakes Artificial Entrance, Australia (1889–2009)

Abstract Analysis of historical survey and navigation charts, aerial imagery, and digital hydro-data (representing a time-series of 1889–2009) allows the morphological evolution of a flood-tide delta at the artificial entrance to the Gippsland Lakes (Victoria, Australia) to be visualised and quantified. Analysis shows that flood-tide delta growth has imposed progressively greater demands upon port managers for publicly funded maintenance dredging. This flood-tide delta growth corresponds with a progressive diminution of Gippsland Lakes catchment river discharge volumes, and dampening of flow variability, due to both regional precipitation pattern changes and changes in catchment water resource allocation. Future climate change predictions for the Gippsland Lakes catchment and coastal area suggest both further decreases in catchment river discharge, and changing sediment flux along this sector of the Ninety Mile Beach. Thus, scope for flood-tide delta nourishment will probably increase, as will the demand for mitigation of the inevitable effects upon entrance channel navigability. Information derived from the analysis of time-series bathymetry used for this study offers baseline information in support of stakeholder consensus building regarding options for maintaining navigability. Analysis points to the merit of considering (and testing via morphological modelling) alternative options for navigation channel maintenance than those in present practice. We argue that the circumstances prevailing at the artificial entrance call for consideration of engineered configuration changes practised elsewhere by entrance managers faced with similar issues.

GA-SVM Based Framework for Time Series Forecasting

A framework (hereby named GA-SVM) for time series forecasting was formed by integration of the particular power of Genetic Algorithms (GAs) with the modeling power of the Support Vector Machine (SVM). The proposed system has potential to capture the benefits of both fascinating fields into a single framework. GAs offer high capability in choosing inputs that are relevant and necessary in predicting dependent variables. With these selected inputs, SVM becomes more accurate in modeling the estimation problems. Experiments demonstrated that the integrated GA-SVM approach is superior compared to conventional SVM applications.

Morphological Change at the Snowy River Ocean Entrance, Victoria, Australia (1851–2008)

Abstract Analysis of data, including historical documentation, survey and navigation charts, and aerial imagery, representing a time series of 1851–2008 for the Snowy River ocean entrance area (located in East Gippsland, Victoria, Australia) shows that much morphological change has occurred, including entrance channel migration along 8000 m of Holocene sandy barrier formation. Increasingly frequent episodes of Snowy River entrance channel closure to Bass Strait is apparent from reference to the 1981–2008 record. The deployment of GIS technology allows such long-term coastal zone change to be visualised and documented, and, to some extent, quantified. Explanations for this change relate primarily to altered stream flow regimes. Within the Snowy River catchment, hydrological processes have been irretrievably altered after the development of the Snowy Mountains Hydro-electricity Scheme (SMHS) from 1951, which currently appropriates the vast majority of annual discharge from the high rainfall and snowfall areas of the upper Snowy River catchment. Loss of Snowy River discharge volume in the post-SMHS period also refers to a steady diminution of stream flow yield from the unregulated sub-catchments, due to a reduction in catchment rainfall. Whilst ebb-flow augmentation via stream flow discharge is essential to the maintenance of the Snowy River entrance, both long-term below-average catchment rainfall and snow coverage, together with future climate change predictions, leave provision of legislated flow targets for the lower Snowy River in question. Thus, the Snowy River entrance is likely to remain ephemeral in the future as a direct consequence of inter-regional water transfer and climate change.

Channel Dredging Trials at Lakes Entrance, Australia: A GIS-Based Approach for Monitoring and Assessing Bathymetric Change

Abstract Dredging trials using trailing suction hopper dredging (TSHD) equipment were carried out across both flood- and ebb-tide deltas at the artificial entrance to the Gippsland Lakes (Victoria, Australia) during March to July 2008. These trials were designed to evaluate options for future sediment management at this location. Regular hydrodata capture before, during, and after the TSHD trials period allowed geographic information systems (GIS)–based monitoring of TSHD performance and overall flood- and ebb-tide delta bathymetric evolution. Results show that the TSHD dredging approach is far more effective in terms of net flood- and ebb-tide delta volumetric reduction, and navigation channel maintenance, than previously used maintenance dredging approaches (which relied upon the use of side-cast and cutter-suction dredging equipment). However, after the culmination of the trials, channel infill quickly took place. The information derived from analysis of the time-series bathymetry used for this study offers baseline information in support of future stakeholder consensus building regarding options for maintaining navigability and, thus, port viability.

Spatial Decision Support for Integrated Coastal Zone Management (ICZM) in Victoria, Australia: Constraints and Opportunities

Abstract Since the United Nations Conference on Environment and Development (1992), the Integrated Coastal Zone Management (ICZM) concept has been adopted by Australian states, including the state of Victoria, as the framework vehicle to guide coastal management. Conceptually vital to the ICZM process is that appropriate environmental, social, demographic, and economic information should be available to all stakeholder groups, such that informed decision making can be supported across the entire catchment–marine–coastal continuum. It has been noted, both internationally and in Australia, that spatial information and related enabling technologies (e.g., geographical information systems –) have much potential to enhance the level of decision support for ICZM practitioners. However, despite much policy innovation regarding ICZM and spatial information infrastructure in Victoria since the early 1990s, stakeholders within the Victorian ICZM program are not yet served by any form of coordinated spatial information provision framework or any capacity-building initiatives vis-à-vis the application of spatial enabling technologies for ICZM. In this paper, we report the findings of an anonymous online survey (responses n = 342) administered to all Victorian ICZM stakeholder groups, which aimed to obtain baseline data regarding spatial information and enabling technology use. Survey results show that despite policy development and innovation at state government level, the current deployment of spatial information and its associated stakeholder-focussed decision-support technology does not meet its potential for decision support in bringing ICZM policy to practice. Results indicate that the initiation of targeted capacity-building programs, aimed specifically at increasing the capability of ICZM practitioners regarding the application of spatial information and enabling technologies, should be considered by lead agencies in order to provide an enhanced level of decision support within the Victorian ICZM program.

The Optimal Rule Structure for Fuzzy Systems in Function Approximation by Hybrid Approach in Learning Process

A hybrid approach of learning process is investigated to optimize the fuzzy rule structure of the fuzzy system for function approximation. First, if-then rules are initialized more much than usual and then are optimized via deployment of a genetic algorithm. Subsequently, the supervised gradient descent algorithm (incorporated momentum technique) is utilized in order to tune the fuzzy rule parameters. Experimental results are presented that indicate significant improvement in term of accuracy in function approximation can be achieved during deployment of the standard additive model (SAM) by adopting the hybrid approach.

Generic Models of Sports Governance and Their Potential for Sustainability

This chapter discusses how generic governance models may influence sporting organisations in Australia to improve their prospects for utility and sustainability. It draws on a research study that focused on the sports of bowls, hockey and swimming which examined how governance, and management structures and practices affected a sport’s capacities in revenue generation and sustainability. (The Project Team comprised the authors and Dr. Robert Kidston (Senior Consultant, Governance and Management Improvement, Innovation and Best Practice Program, Australian Sports Commission), Mr. Rob Clement (General Manager, Innovation and Best Practice, Australian Sports Commission), Mr. Stephen Fox (Senior Consultant, Australian Sports Commission). The Project Team acknowledges with gratitude research assistance, literature review, interviews with participants and a report entitled, The Influence of Governance and Management on the Capacity for Revenue Raising by Sporting Organisations, Preliminary Report, unpublished (copy on file with authors), conducted and/or provided by Mr. J A (Jim) Ferguson (Consultant, former Executive Director of the Australian Sports Commission)). The results of the study are considered within the context of two broad questions on sport governance: