Marine macroalgal biodiversity hotspots: why is there high species richness and endemism in southern Australian marine benthic flora?

The southern Australian marine macroalgal flora has the highest levels of species richness and endemism of any regional macroalgal flora in the world. Analyses of species composition and distributions for the southern Australian flora have identified four different floristic elements, namely the southern Australian endemic element, the widely distributed temperate element, the tropical element and a cold water element. Within the southern Australian endemic element, four species distribution patterns are apparent, thought to largely result from the Jurassic to Oligocene fragmentation of East Gondwana, the subsequent migration of Tethyan ancestors from the west Australian coast and the later invasion of high latitude Pacific species. Climatic deterioration from the late Eocene to the present is thought responsible for the replacement of the previous tropical south coast flora by an endemic temperate flora which has subsequently diversified in response to fluctuating environmental conditions, abundant rocky substrata and substantial habitat heterogeneity. High levels of endemism are attributed to Australia's long isolation and maintained, as is the high species richness, by the lack of recent mass extinction events. The warm water Leeuwin Current has had profound influence in the region since the Eocene, flowing to disperse macroalgal species onto the south coast as well as ameliorating the local environment. It is now evident that the high species richness and endemism we now observe in the southern Australian marine macroalgal flora can be attributed to a complex interaction of biogeographical, ecological and phylogenetic processes over the last 160 million years.

The structure of middle management remuneration packages: An application to Australian mine managers

This paper investigates the composition of remuneration packages for middle managers and relates the structure of remuneration contracts to firm-specific attributes. A statutorily defined position in a single industry is studied as an example of middle management. This allows us to control for differences in task complexity across managers and industry-induced factors that could determine differences in remuneration contracts. Higher-risk firms are expected to pay their mine managers a greater proportion of variable salaries and market and/or accounting-based compensation than low-risk firms. Results indicate that high-risk firms pay a higher proportion of variable salaries and more compensation based on market and/or accounting performance.

Research output of Australian general practice: A comparison with medicine, surgery and public health

Objectives: To compare the productivity of Australian general practice in terms of research publications with the productivity of other medical disciplines. Design: A survey of Australian general practice, medicine, surgery and public health publications carried out by manual searching of specific journals and an electronic search of the US National Library of Medicine's PubMed database. Main outcome measures: The number of original research publications by Australian general practitioners, physicians, surgeons and public health physicians during 1999; the relative publication rate of Australian general practice, medicine, surgery and public health over the period 1990-1999. Results: Of original research articles published in 1999, GPs authored 65% (17/26) in Australian Family Physician and 3% (3/90) in the Medical Journal of Australia; physicians published 4% and 37%, respectively. The electronic search identified 54 research articles relating to Australian general practice published in 1999 in 21 different journals, only two of which were primary care journals. Over the period 1990-1999, there was a publication rate of one general practice [discipline] article per 1000 GPs in practice per year. Corresponding rates for medicine, surgery and public health were 105/1000, 61/1000 and 148/1000, respectively. Conclusions: There is considerable disparity between the level of research output of general practice and that of the disciplines of medicine, surgery and public health. If we are to have effective general practice research, we urgently need to develop research skills, a supportive infrastructure and a culture that nurtures research.

Phenotypic and genetic analyses of a short measure of psychosis-proneness in a large-scale Australian twin study

Previous genetic analyses of psychosis proneness have been limited by their small sample size. For the purposes of large-scale screening, a 12-item questionnaire was developed through a two-stage process of reduction from the full Chapman and Chapman scales. 3685 individuals (including 1438 complete twin pairs) aged 18–25 years and enrolled in the volunteer Australian Twin Registry returned a mail questionnaire which included this psychosis proneness scale and the Eysenck Personality Questionnaire. Despite the brevity of the questionnaire, item and factor analysis identified four unambiguous and essentially uncorrelated scales. There were (1) Perceptual Aberration – Magical Ideation; (2) Hypomania – Impulsivity/Nonconformity; (3) Social Anhedonia and (4) Physical Anhedonia. Model-fitting analyses showed additive genetic and specific environmental factors were sufficient for three of the four scales, with the Social Anhedonia scale requiring also a parameter for genetic dominance. There was no evidence for the previously hypothesised sex differences in the genetic determination of psychosis-proneness. The potential value of multivariate genetic analysis to examine the relationship between these four scales and dimensions of personality is discussed. The growing body of longitudinal evidence on psychosis-proneness suggests the value of incorporating this brief measure into developmental twin studies.