A novel DRD2 single-nucleotide polymorphism associated with schizophrenia predicts age of onset: HapMap tag-sincle-nucleotide polymorphism analysis

Background: Dopamine D2 receptor (DRD2) is thought to be critical in regulating the dopaminergic pathway in the brain which is known to be important in the aetiology of schizophrenia. It is therefore not surprising that most antipsychotic medication acts on the Dopamine D2 receptor. DRD2 is widely expressed in brain, levels are reduced in brains of schizophrenia patients and DRD2 polymorphisms have been associated with reduced brain expression. We have previously identified a genetic variant in DRD2, rs6277 to be strongly implicated in schizophrenia susceptibility. Methods: To identity new associations in the DRD2 gene with disease status and clinical severity, we genotyped seven single nucleotide polymorphisms (SNPs) in DRD2 using a multiplex mass spectrometry method. SNPs were chosen using a haplotype block-based gene-tagging approach so the entire DRD2 gene was represented. Results: One polymorphism rs2734839 was found to be significantly associated with schizophrenia as well as late onset age. Individuals carrying the genetic variation were more than twice as likely to have schizophrenia compared to controls. Conclusions: Our results suggest that DRD2 genetic variation is a good indicator for schizophrenia risk and may also be used as a predictor age of onset

Guided by the light: Roost choice and behaviour of urban Rainbow Lorikeets (Trichoglossus haematodus)

1. The formation of large communal roosts is a conspicuous phenomenon associated with a wide range of bird species successfully exploiting urban environments. In many Australian cities, the abundance of the Rainbow Lorikeet (Trichoglossus haematodus), a native parrot, has increased markedly in recent decades, with the species roosting in very large numbers within suburban sites. These roosting locations are noisy and cause significant fouling of the land beneath, resulting in conflict with humans.2. We investigated the selection of roosting sites in this species in Brisbane, Australia, by comparing characteristics of both the general sites of these roosts as well as individual trees used within roosting sites and trees that were avoided.3. Lorikeets used a wide variety of tree types for roosting but demonstrated a clear preference for clumped trees within sparsely treed areas that received significantly more artificial light at night than otherwise suitable sites  and trees nearby.4. These features of roosting sites may enhance the detection of nocturnal predators by Rainbow Lorikeets, suggesting a potential positive impact of anthropogenic lighting. Our findings provide valuable insights into the management of roost-related conflicts in urban areas. We encourage further investigations into the possible benefits of artificial light

Strategic Interaction amongst Australia’s East Coast Ports

Australia’s principal container ports, located in its state capitals, are owned and operated by state authorities that largely return profits from port operations to state governments. Since they govern the volumes of trade in most merchandise, they command immense influence over the openness and flexibility of the national economy. In this study, we estimate the elasticities of substitution between services of ports in Brisbane, Sydney and Melbourne. We also examine the pricing of port services to estimate the extent of their interaction, from which we derive conjectural variations parameters to assess the actual and potential levels of price collusion. The results confirm that there is considerable potential for destructive oligopoly behaviour and that pricing by the apparently isolated Port of Melbourne has been effectively controlled by price-cap regulation. The services of the ports of Sydney and Brisbane are comparatively substitutable, however. Although their regulation appears to be less restrictive, this substitutability appears to result in some level of competition, which aids in the control of pricing.

Analysis of spacing for spotted gum plantations for maximising merchantable logs' volume in South East Queensland, Australia

Spotted gum (Corymbia citriodora subspecies Variegata) has the potential to be the major hardwood species for large-scale plantations in South East Queensland, Australia, but production research is limited due to the lack of age of research plots. Optimal spacing is a major subject of concern. Based on time series data from a spotted gum experiment site, growth performance is analysed for five spacing levels: ─11.3 m x 11.3 m (78 stems per hectare), 7.4 m x 7.4 m (182 sph), 5.4 m x 5.4 m (343 sph), 3.6 m x 3.6 m (771 sph) and 2.9 m x 2.9 m (1189 sph). The major objective was assumed to be to maximise total merchantable log volume. A growth model was produced, and the mean diameter at breast height (dbh) and total merchantable log volume for each spacing levels at a range of harvesting ages was estimated. From the analysis, the spacing level of 5.4 m x 5.4 m was found to be optimal for maximising merchantable log volume to 10 cm small-end diameter. Further analysis of mean dbh, height and volume of the largest 200 and 250 trees from this spacing level indicates that merchantable log volume could be maximised by retaining the 250 largest trees per hectare. The total financial revenue from the best spacing level in 25 and 30 years are predicted to be $13,637 and$17,779 per hectare, respectively. If full rotation data could be obtained, more reliable models could be produced, and a more accurate financial estimate could be made

Modelling residential water demand with fixed volumetric charging in a large urban municipality: The case of Brisbane, Australia

This paper uses household level data to model residential water demand in Brisbane, Australia from 1998 to 2004. In this system, residential consumption is charged using a fixed annual service fee with no free entitlement and a fixed volumetric charge per kilolitre. Water demand is specified as quarterly household water consumption and demand characteristics include the contemporaneous and lagged marginal price of water, household income and size, and the number of rainy (with at least some precipitation) and warm (greater than 19.5°C) days. The findings not only confirm residential water as price and income inelastic, but also that the price and income elasticity of demand in owner-occupied households is higher than in renter households. However, the results also show that weather, especially the number of warm days, is likely to exert a much greater influence on residential water consumption than any factors subject to the usual demand management strategies.Residential water demand, two-part tariffs, fixed volumetric charge, demand management strategies

Urban water demand with fixed volumetric charging in a large municipality: the case of Brisbane, Australia

This paper uses suburb-level quarterly data to model residential water demand in Brisbane, Australia, from 1998 to 2003. In this system, residential consumption is charged using a fixed annual service fee with no water entitlement followed by a fixed volumetric charge per kilolitre. Water demand is specified as average quarterly household water consumption and the demand characteristics include the marginal price of water, household income and size, and the number of rainy and warm days. The findings not only confirm residential water as price and income inelastic, but also that the price and income elasticity of demand in owner-occupied households is higher than in rented households. The results also show that weather, particularly summer months and the number of rainy days, exerts a strong influence on residential water consumption.water management and policy, demand analysis, utility regulation and pricing, Resource /Energy Economics and Policy,