Woodleigh, Southern Carnarvon Basin, Western Australia: history of discovery, Late Devonian age, and geophysical and morphometric evidence for a 120 km-diameter impact structure

The discovery of the Woodleigh impact structure, first identified by R. P. lasky, bears a number of parallels with that of the Chlcxulub impact structure of K-T boundary age, underpinning complications inherent in the study of buried impact structures by geophysical techniques and drilling. Questions raised in connection with the diameter of the Woodleigh impact structure reflect uncertainties in criteria used to define original crater sizes in eroded and buried impact structures as well as limits on the geological controls at Woodleigh. The truncation of the regional Ajona - Wandagee gravity ridges by the outer aureole of the Woodleigh structure, a superposed arcuate magnetic anomaly along the eastern part of the structure, seismic-reflection data indicating a central > 37 km-diameter dome, correlation of fault patterns between Woodleigh and less-deeply eroded impact structures (Ries crater, Chesapeake Bay), and morphometric estimates all indicate a final diameter of 120 km. At Woodleigh, pre-hydrothermal shock-induced melting and diaplectic transformations are heavily masked by pervasive alteration of the shocked gneisses to montmorillonite-dominated clays, accounting for the high MgO and low K2O of cryptocrystalline components. The possible contamination of sub-crater levels of the Woodlelgh impact structure by meteoritic components, suggested by high Ni, Co, Cr, Ni/ Co and Ni/Cr ratios, requires further siderophile element analyses of vein materials. Although stratigraphic age constraints on the impact event are broad (post-Middle Devonian to pre-Early Jurassic) high-temperature (200-250 degrees C) pervasive hydrothermal activity dated by K-Ar isotopes of illite - smectite indicates an age of 359 +/- 4 Ma. To date neither Late Devonian crater fill, nor impact ejecta fallout units have been identified, although metallic meteoritic ablation spherules of a similar age have been found in the Conning Basin.

First development of a polyurethane keratoprosthesis and its Australian connection: An unbeknown episode in the history of artificial cornea

This paper is aimed at establishing a particular chronological priority issue in the convoluted history of artificial cornea. According to existing records, the first keratoprosthesis made from polyurethane was developed by Caldwell and Jacob-Labarre in the late 1980s. This paper demonstrates that in fact the first polyurethane keratoprosthesis was proposed and designed in 1985 by Lawrence Hirst, an Australian ophthalmologist then working in St Louis, USA. The first prototype was manufactured in January 1986 by Thermedics Inc according to Dr Hirst's instructions from Tecoflex, a transparent polyurethane developed by the same company. This keratoprosthesis, which also had a porous skirt, was inserted intralamellarly in a monkey cornea and followed up clinically for about 3 months. There were no significant postoperative complications, and the histology of the explant indicated proper biointegration of the prosthetic skirt within the host stromal tissue. Because of a delay in the manufacture of further prototypes and to Dr Hirst's decision to return to Australia, the project was eventually abandoned. As no report was published on this development, the present paper is entirely based on original documents held in Dr Hirst's archives.

The evolutionary history of Symbiodinium and scleractinian hosts - Symbiosis, diversity, and the effect of climate change

Marine invertebrates representing at least five phyla are symbiotic with dinoflagellates from the genus Symbiodinium. This group of single-celled protists was once considered to be a single pandemic species, Symbiodinium microadriaticum. Molecular investigations over the past 25 years have revealed, however, that Symbiodinium is a diverse group of organisms with at least eight (A-H) divergent clades that in turn contain multiple molecular subclade types. The diversity within this genus may subsequently determine the response of corals to normal and stressful conditions, leading to the proposal that the symbiosis may impart unusually rapid adaptation to environmental change by the metazoan host. These questions have added importance due to the critical challenges that corals and the reefs they build face as a consequence of current rapid climate change. This review outlines our current understanding of the diverse genus Symbiodinium and explores the ability of this genus and its symbioses to adapt to rapid environmental change. (c) 2006 Rubel Foundation, ETH Zurich. Published by Elsevier GmbH. All rights reserved.

Movement and figurality: The circulation diagram and the history of the architectural plan

Knowledge of the plan competes with self-consciousness of experience. The less we are able to understand our spatio-visual experience by the abstract coordinates of the plan, the more we are thrust back into a lived experience of the building in duration. This formula, frequently unacknowledged, has been one of the main precepts of the experientialist modernism which arises out of the picturesque and which stands in critique of classical idealism. One of the paths to critique this formula is by showing that the attention to the experience of the spaces in duration is predicated on obscuring, complicating and weakening the apprehension of the plan as a figure. Another development in the practice of modern planning has been architects using a kind of over-drawing where human circulation diagrams or 'movement lines' are drawn expressively across the orthographic plane; thus representing the lived experience of buildings. We will show that these two issues are linked; the plan's weak figure and the privilege this supposes for durational experience has a corollary - experience itself demands to be visible in the plan, and this is one origin of the present fascination with 'diagramming'. In this paper we explore the practice of architectural planning and its theoretical underpinnings in an attempt to show the viability of a history of architectural planning methods.