Age-at-first-admission of schizophrenia, bipolar disorder and major depression: Implications of heterogeneity

Age of onset is an important variable when considering the cause and course of mental illnesses. Given the debate about the relationship between psychotic disorders it would be useful to compare age-at-first-admission for ICD schizophrenia and for affective psychoses when the latter is differentiated into 'major depression' and 'bipolar disorder'. Data on age-at-first-admission for Australian-born individuals diagnosed with schizophrenia (ICD 295) or affective psychosis (ICD 296) were extracted from the Queensland Mental Health Statistics System -- a comprehensive, namelinked mental health register. Because the ICD 9 category 296.1 was used to code what is now called "major depressive episode', this group was differentiated from other 296 categorieswhich were considered bipolar disorders. Those receiving more than one diagnoses within these categories were excluded. All distributions show a wide age range of onset from early adolescence into the seventies and eighties. However the modal age-group for major depression ('60-69' for both sexes) is clearly different from bipolar disorder ('20-29' for males; '30- 39' for females), the latter distribution being more similar to the SCZ distribution (which had a model age-group of '20-29' for both sexes). While these distributions were similar for males and females, there were sex differences in the proportions within each diagnostic group: more males with schizophrenia, and more females with bipolar disorder and with major depression. Our results suggest heterogeneity within the affective psychoses as categorised by ICD 9, with bipolar disorder having an age-at-first-admission distribution more similar to schizophrenia than major depression. The Stanley Foundation supported this project.

Determining forest structural attributes using an inverted geometric-optical model in mixed eucalypt forests, Southeast Queensland, Australia

The Montreal Process indicators are intended to provide a common framework for assessing and reviewing progress toward sustainable forest management. The potential of a combined geometrical-optical/spectral mixture analysis model was assessed for mapping the Montreal Process age class and successional age indicators at a regional scale using Landsat Thematic data. The project location is an area of eucalyptus forest in Emu Creek State Forest, Southeast Queensland, Australia. A quantitative model relating the spectral reflectance of a forest to the illumination geometry, slope, and aspect of the terrain surface and the size, shape, and density, and canopy size. Inversion of this model necessitated the use of spectral mixture analysis to recover subpixel information on the fractional extent of ground scene elements (such as sunlit canopy, shaded canopy, sunlit background, and shaded background). Results obtained fron a sensitivity analysis allowed improved allocation of resources to maximize the predictive accuracy of the model. It was found that modeled estimates of crown cover projection, canopy size, and tree densities had significant agreement with field and air photo-interpreted estimates. However, the accuracy of the successional stage classification was limited. The results obtained highlight the potential for future integration of high and moderate spatial resolution-imaging sensors for monitoring forest structure and condition. (C) Elsevier Science Inc., 2000.

Community care and criminal offending in schizophrenia

Background The introduction of community care in psychiatry is widely thought to have resulted in more offending among the seriously mentally ill. This view affects public policy towards and public perceptions of such people. We investigated the association between the introduction of community care and the pattern of offending in patients with schizophrenia in Victoria, Australia. Methods We established patterns of offending from criminal records in two groups of patients with schizophrenia over their lifetime to date and in the 10 years after their first hospital admission. One group was first admitted in 1975 before major deinstitutionalisation in Victoria, the second group in 1985 when community care was becoming the norm. Each patient was matched to a control, by age, sex, and place of residence to allow for changing patterns of offending over time in the wider community. Findings Compared with controls, significantly more of those with schizophrenia were convicted at least once for ail categories of criminal offending except sexual offences (relative risk of offending in 1975=3.5 [95% CI 2.0-5.5), p=0.001, in 1985=3.0 [1.9-4.9], p=0.001). Among men, more offences were committed in the 1985 group than the 1975 group, but this was matched by a similar increase in convictions among the community controls. Those with schizophrenia who had also received treatment for substance abuse accounted for a disproportionate amount of offending. Analysis of admission data for the patients and the total population of admissions with schizophrenia showed that although there had been an increase of 74 days per annum spent in the community for each of the study population as a whole, first admissions spent only 1 more day in the community in 1985 compared with 1975. Interpretation Increased rates in criminal conviction for those with schizophrenia over the last 20 years are consistent with change in the pattern of offending in the general community. Deinstitutionalisation does not adequately explain such change. Mental-health services should aim to reduce the raised rates of criminal offending associated with schizophrenia, but turning the clock back on community care is unlikely to contribute towards any positive outcome.

Regional-scale investigation of the spatial distribution and origin of soluble salts in central north Queensland

A method for regional assessment of the distribution of saline outbreaks is demonstrated for a large area (68 000 km(2)) in north Queensland, Australia. Soil samples were used in conjunction with a digital elevation model and a map of potentially saline discharge zones to examine the landscape distribution of soluble salts in the region. The hypothesis of atmospheric accession of salt was tested for the topographically defined catchment regions feeding into each potentially saline discharge area. Most catchments showed a salt distribution consistent with this hypothesis, i.e. %TSS was large near the discharge areas and decreased rapidly with distance uphill from the discharge areas. In some catchments, however, local saline outbreaks were apparent at significant distances uphill from discharge areas. The possibility of geological sources of this salt was examined by comparing random point distributions with the location of saline points with distance downhill from geological units (excluding points near discharge zones). The distribution of some saline outbreaks was consistent with the occurrence of Cambro-Ordovician metasediments, Devonian limestone, Upper Devonian-Lower Carboniferous volcanics, and Triassic sediments. Copyright (C) 2000 John Wiley & Sons, Ltd.

The status of Petalocotyle Ozaki, 1934 (Digenea : Gyliauchenidae), including the description of two new species from acanthurid fishes in Queensland, Australia

The status of Petalocotyle Ozaki, 1934 within the Gyliauchenidae Goto & Matsudaira, 1918 is reviewed. Two new species, P. adenometra from Prionurus microlepidotus (Amity Point, Queensland, Australia) and P. diverticulata from Acanthurus nigrofuscus and A. lineatus (Heron Island, Queensland, Australia), are described. The body plan of Petalocotyle conforms to that of members of the Gyliauchenidae (oral sucker absent, well-developed pharynx, complex oesophagus and characteristic male terminal genitalia), indicating justifiable inclusion in this family. A new diagnosis is given for the genus, such that Petalocotyle is now identified by the presence of an anterior, protuberant ventral sucker, long caeca, a large, sigmoid cirrus-sac containing a coiled ejaculatory duct, and an extensive vitellarium. We suggest that, of all the known genera of gyliauchenids, Petalocotyle may most closely resemble the 'archaetypal gyliauchenid', that is, it may be placed basally within the radiation of the Gyliauchenidae. However, derived characters, like diverticula in the reproductive system, indicate that some characters of individual members of Petalocotyle may be considered advanced and do not reflect an archaetypal condition. Parallels in the structure of the male and female genitalia of Robphildollfusium Paggi & Orecchia, 1963 and Petalocotyle, along with the shared morphology of the digestive tract, indicate possible phylogenetic links between the two genera. This affinity is difficult to infer using morphology alone and recommend that Robphildollfusium remain detached from the Gyliauchenidae.

Overseas visitors admitted to Queensland hospitals for water-related injuries

Objective: To determine the number of overseas visitors admitted to Queensland hospitals for water-related injuries over three years, the causes of their injuries, the resulting conditions treated, and the type of hospitals to which they were admitted. Design: Retrospective analysis of admissions of overseas visitors to Queensland hospitals over the three financial years 1995/96, 1996/97 and 1997/98. Patients: 296 overseas visitors admitted for water-related injuries, identified from hospital records by their usual place of residence. Main outcome measures: Number of admissions, causes of injuries, conditions treated. and bed days occupied by these patients at different types of hospitals (metropolitan, regional and rural public hospitals, and private hospitals). Results: The 296 overseas visitors accounted for a total of 596 separate admissions, many of these the result of patients with decompression illness being admitted several times to a regional hospital hyperbaric chamber for treatment as day patients. The largest number of injuries involved the use of diving equipment. The main conditions treated were decompression illness (54.7%), fractures and dislocations (15.5%), and drowning and non-fatal submersion (14.9%). Overall, overseas visitors admitted to hospital following a water-related incident occupied 1215 bed days; 90% of these admissions were to regional hospitals. Conclusions: The main reason for admission of overseas visitors is for decompression illness, suggesting that the prevention of injuries among scuba divers requires further coordinated efforts by health and tourism authorities.

Petrographic and isotope constraints on the origin of authigenic carbonate minerals and the associated fluid evolution in Late Permian coal measures, Bowen Basin (Queensland), Australia

Authigenic carbonate minerals are ubiquitous throughout the Late Permian coal measures of the Bowen Basin, Queensland, Australia. In the northern Bowen Basin, carbonates include the following assemblages: siderite I (delta O-18(SMOW) = +11.4 to + 17%, delta C-13(PDB) = - 5.3 to + 120), Fe-Mg calcite-ankerite-siderite II mineral association (delta O-18(SMOW) = +7.2 to + 10.20, delta C-13(PDB) = 10.9 to - 1.80 for ankerite) and a later calcite (delta O-18(SMOW) = +5.9 to + 14.60, delta C-13(PDB) = -11.4 to + 4.40). In the southern Bowen Basin, the carbonate phase consists only of calcite (delta O-18(SMOW) = +12.5 to + 14.80, delta C-13(PDB) = -19.4 to + 0.80), where it occurs extensively throughout all stratigraphic levels. Siderite I occurs in mudrocks and sandstones and predates all other carbonate minerals. This carbonate phase is interpreted to have formed as an early diagenetic mineral from meteoric waters under cold climate and reducing conditions. Fe-Mg calcite-ankerite-siderite Il occur in sandstones as replacement of volcanic rock fragments. Clay minerals (illite-smectite, chlorite and kaolinite) postdate Ca-Fe-Mg carbonates, and precipitation of the later calcite is associated with clay mineral formation. The Ca-Fe-Mg carbonates and later calcite of the northern Bowen Basin are regarded as having formed as a result of hydrothermal activity during the latest Triassic extensional tectonic event which affected this part of the basin, rather than deep burial diagenesis during the Middle to Late Triassic as previously reported. This hypothesis is based on the timing relationships of the authigenic mineral phases and the low delta O-18 values of ankerite and calcite, together with radiometric dating of illitic clays and recently published regional geological evidence. Following the precipitation of the Ca-Fe-Mg carbonates from strongly O-18-depleted meteoric-hydrothermal fluids, continuing fluid circulation and water-rock interaction resulted in dissolution of these carbonate phases as well as labile fragments of volcaniclastic rocks. Subsequently, the later calcite and day minerals precipitated from relatively evolved (O-18-enriched) fluids. The nearly uniform delta O-18 values of the southern Bowen Basin calcite have been attributed to very low water/rock ratio in the system, where the fluid isotropic composition was buffered by the delta O-18 values of rocks. (C) 2000 Elsevier Science B.V. All rights reserved.

Assisting decision-making in Queensland barley production through chance constrained programming

A chance constrained programming model is developed to assist Queensland barley growers make varietal and agronomic decisions in the face of changing product demands and volatile production conditions. Unsuitable or overlooked in many risk programming applications, the chance constrained programming approach nonetheless aptly captures the single-stage decision problem faced by barley growers of whether to plant lower-yielding but potentially higher-priced malting varieties, given a particular expectation of meeting malting grade standards. Different expectations greatly affect the optimal mix of malting and feed barley activities. The analysis highlights the suitability of chance constrained programming to this specific class of farm decision problem.

Modelling socially optimal land allocations for sugar cane growing in North Queensland: a linked mathematical programming and choice modelling study

A modelling framework is developed to determine the joint economic and environmental net benefits of alternative land allocation strategies. Estimates of community preferences for preservation of natural land, derived from a choice modelling study, are used as input to a model of agricultural production in an optimisation framework. The trade-offs between agricultural production and environmental protection are analysed using the sugar industry of the Herbert River district of north Queensland as an example. Spatially-differentiated resource attributes and the opportunity costs of natural land determine the optimal tradeoffs between production and conservation for a range of sugar prices.

Redating the onset of burning at Lynch's Crater (North Queensland): implications for human settlement in Australia

Lynch's Crater preserves a continuous, high-resolution record of environmental changes in north Queensland. This record suggests a marked increase in burning that appears to be independent of any known major climatic boundaries. This increase is accompanied, or closely followed, by the virtually complete replacement of rainforest by sclerophyll vegetation. The absence of any major climatic shift associated with this increase in fire frequency therefore has been interpreted as a result of early human impact in the area. The age for this increase in burning, on the basis of conventional radiocarbon dating, was previously thought to be approximately 38000 C-14 yr BP, supporting the traditional model for human arrival in Australia at 40 000 C-14 yr BP Here we have applied a more rigorous pre-treatment and graphitisation procedure for radiocarbon dating samples from the Lynch's Crater sequence. These new dates suggest that the increase in fire frequency occurred at 45 000 C-14 yr BP, supporting the alternative view that human occupation of Australia occurred by at least 45 000-55 000 cal. yr BP. Copyright (C) 2001 John Wiley & Sons, Ltd.

Retaining rural and remote area nurses - The Queensland, Australia experience

Because higher-than-average turnover rates for nurses who work in remote and rural areas are the norm, the authors conducted a study to identify professional and personal factors that influenced rural nurses' decisions to resign. Using a mail survey, the authors gathered qualitative and quantitative data from nurses who had resigned from rural and remote areas in Queensland, Australia. Their findings, categorized into professional and rural influences, highlight the importance of work force planning strategies that capitalize on the positive aspects of rural and remote area practice, to retain nurses in nonmetropolitan areas.