West elevation, General Purpose North 3, University of Queensland, St Lucia

Formal elevation facing University of Queensland entrance roads.

West elevation, General Purpose North 3, University of Queensland, St Lucia

Formal elevation facing University of Queensland entrance roads.

West elevation, General Purpose North 3, University of Queensland, St Lucia

Formal elevation facing University of Queensland entrance roads.

Prevalence of Parkinson’s disease in metropolitan and rural Queensland: A general practice survey

The prevalence of idiopathic Parkinson’s disease (IPD) in Australia is unclear. We estimated the prevalence of IPD, and other forms of parkinsonism, through the study of typical caseloads in general practice. A random sample of general practitioners (GPs) throughout Queensland (401 responses from 528 validated practice addresses) was asked to estimate the numbers of patients with IPD and parkinsonism seen in the preceding year. The estimated prevalence of diagnosed IPD in Queensland was 146 per 100 000 (95% CI = 136–155). A further 51 per 100 000 in the population were suspected by doctors to have IPD without formal diagnosis, whereas another 51 per 100 000 people may have non-idiopathic parkinsonism. Idiopathic Parkinson’s disease was more common in rural than metropolitan areas. Although most GPs were confident in making diagnoses of IPD, the majority had little or no confidence in their ability to treat the disease, especially in its later stages. Support from neurologists was perceived by GPs to be very good in cities, but poor in remote areas.

Bimanual aiming and overt attention: one law for two hands

Reaching to interact with an object requires a compromise between the speed of the limb movement and the required end-point accuracy. The time it takes one hand to move to a target in a simple aiming task can be predicted reliably from Fitts' law, which states that movement time is a function of a combined measure of amplitude and accuracy constraints (the index of difficulty, ID). It has been assumed previously that Fitts' law is violated in bimanual aiming movements to targets of unequal ID. We present data from two experiments to show that this assumption is incorrect: if the attention demands of a bimanual aiming task are constant then the movements are well described by a Fitts' law relationship. Movement time therefore depends not only on ID but on other task conditions, which is a basic feature of Fitts' law. In a third experiment we show that eye movements are an important determinant of the attention demands in a bimanual aiming task. The results from the third experiment extend the findings of the first two experiments and show that bimanual aiming often relies on the strategic co-ordination of separate actions into a seamless behaviour. A number of the task specific strategies employed by the adult human nervous system were elucidated in the third experiment. The general strategic pattern observed in the hand trajectories was reflected by the pattern of eye movements recorded during the experiment. The results from all three experiments demonstrate that eye movements must be considered as an important constraint in bimanual aiming tasks.

Wolbachia: Invasion biology in South Pacific butterflies

Wolbachia ensdosymbionts are well known for their ability to manipulate the population biology and development of their hosts. One of the less studied outcomes of Wolbachia infection with this symbiont is the selective killing of male embryos. Recent work on butterflies living on different South Pacific islands is beginning to help us understand the complexity of the co-evolutionary interactions between these partners.

Wolbachia pipientis: bacterial density and unidirectional cytoplasmic incompatibility between infected populations of Aedes albopictus

Unidirectional cytoplasmic incompatibility is seen when certain Wolbachia-infected insect populations are crossed. Two hypotheses might explain this phenomenon: superinfections with mutually incompatible strains of Wolbachia producing incompatibility when crossed to individuals infected with only a single bacterial strain or, alternatively, a bacterial dosage model, with differences in Wolbachia densities responsible for the incompatibility. A quantitative PCR assay was set up as a general method to compare Wolbachia densities between populations. Using this assay in unidirectionally incompatible stocks of the mosquito Aedes albopictus, we have determined that densities are significantly higher in Houston than in the Mauritius and Koh Samui stocks. This is consistent with a dosage model for the observed crossing patterns, but does not rule out the possibility that superinfection is the primary cause of the incompatibility.

16S rRNA phylogenetic analysis of the bacterial endosymbionts associated with cytoplasmic incompatibility in insects

Bacterial endosymbionts of insects have long been implicated in the phenomenon of cytoplasmic incompatibility, in which certain crosses between symbiont-infected individuals lead to embryonic death or sex ratio distortion. The taxonomic position of these bacteria has, however, not been known with any certainty. Similarly, the relatedness of the bacteria infecting various insect hosts has been unclear. The inability to grow these bacteria on defined cell-free medium has been the major factor underlying these uncertainties. We circumvented this problem by selective PCR amplification and subsequent sequencing of the symbiont 16S rRNA genes directly from infected insect tissue. Maximum parsimony analysis of these sequences indicates that the symbionts belong in the α-subdivision of the Proteobacteria, where they are most closely related to the Rickettsia and their relatives. They are all closely related to each other and are assigned to the type species Wolbachia pipientis. Lack of congruence between the phylogeny of the symbionts and their insect hosts suggests that horizontal transfer of symbionts between insect species may occur. Comparison of the sequences for W. pipientis and for Wolbachia persica, an endosymbiont of ticks, shows that the genus Wolbachia is polyphyletic. A PCR assay based on 16S primers was designed for the detection of W. pipientis in insect tissue, and initial screening of insects indicates that cytoplasmic incompatibility may be a more general phenomenon in insects than is currently recognized.

Breastfeeding and the responsibilities of GPs: a qualitative study of general practice registrars

The most recent National Health Survey reports that more than 80% of women initiate breastfeeding, while recent studies describe initiation rates of more than 90%. Yet fewer than 50% of women continue to breastfeed for 6 months or longer. This is at odds with National Health and Medical Research Council recommendations that 80% of infants be exclusively breastfed for the first 6 months of life. Women are more likely to initiate and continue to breastfeed if their doctor supports and encourages them to do so. Conversely, women perceive a neutral attitude by doctors toward breastfeeding to be similar to a negative attitude. Therefore, while doctors may not perceive their support or encouragement to be a determining factor in a woman’s breastfeeding decisions, women often place great emphasis on their GP's attitude to breastfeeding and are much more likely to think that information provided by a doctor is important. No previous research in Australia has addressed the issue of how GPs perceive their roles and responsibilities regarding breastfeeding. As part of a larger research project investigating the breastfeeding skills and knowledge of general practice registrars, this article reports the results of qualitative interviews with eight general practice registrars and their views and beliefs about GPs’ responsibilities to breastfeeding women.