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Models were developed of relationships among water quality, geospatial and species-level diatom data for 465 samples collected from stream sites across south-eastern Australia. Transfer functions were derived from weighted averaging and artificial neural network approaches. Analysis of spatial variations in species assemblages was used to divide the sites into two groups according to site elevation. The strongest predictive models for the upland group associated diatom assemblages with conductivity, longitude, altitude, and to a lesser extent pH, NO x and TKN. The strongest predictors for the lowland group were longitude and conductivity, but artificial neural network models performed well for NO x and temperature. The importance of the geospatial variables suggests that there may be a capacity to develop diatom sub-regions within which robust models for other water quality variables important to management can be generated. [ABSTRACT FROM AUTHOR]

There have been few recent estimates of the prevalence of tinnitus from large population-based samples of older persons. Our study aimed to assess the prevalence and characteristics of prolonged tinnitus in a representative sample of 2015 adults aged 55-99 years, residing in the Blue Mountains, west of Sydney, Australia, during 1997-99. All participants underwent a detailed hearing examination by an audiologist, including comprehensive questions about hearing. After age adjustment, subjects reporting tinnitus had significantly worse hearing at both lower and higher frequencies (p < 0.001). This difference was more marked in younger than in older subjects (p < 0.05). Overall, 602 subjects (30.3%) reported having experienced tinnitus, with 48% reporting symptoms in both ears. Tinnitus had been present for at least 6 years in 50% of cases, and most (55%) reported a gradual onset. Despite tinnitus being described as mildly to extremely annoying by 67%, only 37% had sought professional help, and only 6% had received any treatment. [ABSTRACT FROM AUTHOR]

The development of a broader, more holistic approach to aquatic ecosystem management has been called for in recent years. Physical and chemical objectives alone are no longer considered sufficient for the protection of aquatic ecosystems and should be supplemented with biological objectives. The ubiquitous and sedentary nature of macroinvertebrates, combined with their measurable response to environmental conditions, favour their use as important indicators in environmental policies. To establish biological objectives, there is a need for a regional framework to limit the variability between ecosystems. Past studies have demonstrated that an a posteriori regionalisation approach may be more useful than an a priori approach in explaining single component (e.g. macroinvertebrates) patterns across ecosystems. This is particularly important as aquatic resource management agencies often focus on one or two components of the ecosystem to assess environmental health. This study uses an a posteriori method to delineate and describe biological regions based on edge and riffle macroinvertebrate data. The regionalisation will provide a framework for setting biological objectives, based on the range of reference conditions measured within each separate region. The objectives will include regional checklists for taxa and biotic indices. Predictive modelling in the style of RIVPACS or AUSRIVAS will also be used within each region to develop objectives, incorporating local, regional and systematic features as predictor variables. [ABSTRACT FROM AUTHOR]

Human induced increases to nutrient concentrations in streams have led to many agencies developing strategies and criteria for nutrient reduction. National or statewide guidelines are generally inappropriate, due to the natural variability in stream ecosystems within political boundaries. This study used an extant aquatic macroinvertebrate-based regionalisation for the state of Victoria, Australia, as the basis for defining regions of relatively homogeneous environmental character. This enabled the selection of ecologically-based regional reference sites and subsequent characterisation of the nutrient status of these sites. Using an extensive biological and nutrient data base for streams across the State, we calculated 50th and 75th percentile concentrations for reference sites within each region. Using these percentiles in conjunction with `impact and recovery' studies, we defined nutrient guidelines for each region. Although the nutrient data largely supported the biological regionalisation, patterns in the nutrient data did require some minor modifications for the nutrient regions. Relatively unimpacted regions with reference sites in very good-to excellent-condition were assigned guidelines largely based on the 75th percentiles. The more impacted regions, where `best available' reference sites were of poorer quality, were assigned guidelines based largely on the 50th percentiles. Professional judgement and known extents of impacts across each region provided important contributions to the decision-making process. The derived guideline concentrations are comparable to several cited in the literature and are proposed for use in monitoring, assessment and restoration targets. [ABSTRACT FROM AUTHOR]