Non-homogeneous polygonal Markov fields in the plane: graphical representations and geometry of higher order correlations

We consider polygonal Markov fields originally introduced by Arak and Surgailis (1989). Our attention is focused on fields with nodes of order two, which can be regarded as continuum ensembles of non-intersecting contours in the plane, sharing a number of features with the two-dimensional Ising model. We introduce non-homogeneous version of polygonal fields in anisotropic enviroment. For these fields we provide a class of new graphical constructions and random dynamics. These include a generalised dynamic representation, generalised and defective disagreement loop dynamics as well as a generalised contour birth and death dynamics. Next, we use these constructions as tools to obtain new exact results on the geometry of higher order correlations of polygonal Markov fields in their consistent regime.Comment: 54 page

The cost-effectiveness of coronary calcium score-guided statin therapy initiation for Australians with family histories of premature coronary artery disease

Objectives: To compare the cost-effectiveness of coronary artery calcium (CAC) score-guided statin therapy criteria and American College of Cardiology/American Heart Association (ACC/AHA) guidelines (10-year pooled cohort equation [PCE] risk ≥ 7.5%) with selection according to Australian guidelines (5-year absolute cardiovascular disease risk [ACVDR] ≥ 10%), for people with family histories of premature coronary artery disease. Study design, setting: Markov microsimulation state transition model based on data from the Coronary Artery calcium score: Use to Guide management of Hereditary Coronary Artery Disease (CAUGHT-CAD) trial and transition probabilities derived from published statin prescribing and adherence outcomes and clinical data. Participants: 1083 people with family histories of premature coronary artery disease but no symptomatic cardiovascular disease. Main outcome measures: Relative cost-effectiveness over fifteen years, from the perspective of the Australian health care system, compared with usual care (Australian guidelines), assessed as incremental cost-effectiveness ratios (ICERs), with a notional willingness-to-pay threshold of $50 000 per quality-adjusted lifeyear (QALY) gained. Results: Applying the Australian guidelines, 77 people were eligible for statin therapy (7.1$33 108 (CAC ≥ 100) and $53 028 per QALY gained (CAC > 0); the ACC/AHA guidelines approach (ICER,$909 241 per QALY gained) was not cost-effective. CAC score-guided selection (CAC ≥ 100) was cost-effective for people with 5-year ACVDR of at least 5%. Conclusion: Expanding the number of people at low to intermediate CVD risk eligible for statin therapy should selectively target people with subclinical atherosclerosis identified by CAC screening. This approach can be more cost-effective than simply lowering treatment eligibility thresholds.Prasanna Venkataraman, Amanda L Neil, Geoffrey K Mitchell, Tony Stanton, Stephen Nicholls, Andrew M Tonkin, Gerald F Watts, Thomas H Marwic

Does horizontal transmission invalidate cultural phylogenies?

Phylogenetic methods have recently been applied to studies of cultural evolution. However, it has been claimed that the large amount of horizontal transmission that sometimes occurs between cultural groups invalidates the use of these methods. Here, we use a natural model of linguistic evolution to simulate borrowing between languages. The results show that tree topologies constructed with Bayesian phylogenetic methods are robust to realistic levels of borrowing. Inferences about divergence dates are slightly less robust and show a tendency to underestimate dates. Our results demonstrate that realistic levels of reticulation between cultures do not invalidate a phylogenetic approach to cultural and linguistic evolution

The Development of an Integrated Coastal Simulator for Supporting Long Term Coastal Management

The coastal simulator is designed to provide information on the possible future states of the coast through the 21st Century under a range of climate and socio-economic futures and shoreline management options. It links a series of models within a nested spatial framework that recognises three scales which provide boundary conditions to the smaller scale: (1) “global”; (2) regional (e.g. North Sea); and (3) the simulator domain (defined by discrete physiographic unit(s)). The linked models describe a range of processes, including marine climate (waves, surges and mean sea level), sand bank morphodynamics, wave transformation, shoreline morphodynamics, built environment scenarios, ecosystem change, and erosion and flood risk. The simulator includes a dedicated graphical user interface which allows a range of queries of the results, including visualisations. The prototype simulator is designed to support Shoreline Management Plans (SMP’s), but provides a methodology that could support integrated coastal zone management

General discussion

The Gerhard Herzberg fonds is held at the NRC Archives. Contact [email protected] for information about access.Le fonds Gerhard Herzberg est conserv\ue9 aux Archives du CNRC. Contactez [email protected] pour des informations sur l'acc\ue8s.Peer reviewed: YesNRC publication: Ye