Adverse feedback sequences in exploited marine systems: Are deliberate interruptive actions warranted?

Several mechanisms for self-enhancing feedback instabilities in marine ecosystems are identified and briefly elaborated. It appears that adverse phases of operation may be abruptly triggered by explosive breakouts in abundance of one or more previously suppressed populations. Moreover, an evident capacity of marine organisms to accomplish extensive geographic habitat expansions may expand and perpetuate a breakout event. This set of conceptual elements provides a framework for interpretation of a sequence of events that has occurred in the Northern Benguela Current Large Marine Ecosystem (off south-western Africa). This history can illustrate how multiple feedback loops might interact with one another in unanticipated and quite malignant ways, leading not only to collapse of customary resource stocks but also to degradation of the ecosystem to such an extent that disruption of customary goods and services may go beyond fisheries alone to adversely affect other major global ecosystem concerns (e.g. proliferations of jellyfish and other slimy, stingy, toxic and/or noxious organisms, perhaps even climate change itself, etc.). The wisdom of management interventions designed to interrupt an adverse mode of feedback operation is pondered. Research pathways are proposed that may lead to improved insights needed: (i) to avoid potential 'triggers' that might set adverse phases of feedback loop operation into motion; and (ii) to diagnose and properly evaluate plausible actions to reverse adverse phases of feedback operation that might already have been set in motion. These pathways include the drawing of inferences from available 'quasi-experiments' produced either by short-term climatic variation or inadvertently in the course of biased exploitation practices, and inter-regional applications of the comparative method of science.

Palaeoclimatic implications of the growth history and stable isotope (delta O-18 and delta C-13) geochemistry of a Middle to Late Pleistocene stalagmite from central-western Italy

The age structure and, stable isotope composition of a stalagmite (CC I) from an upland cave in central-western Italy were studied to investigate regional response to global climatic changes. Four growth phases are constrained by 28 thermal ionization and multi-collector inductively coupled plasma mass spectrometry Th-U ages and reveal intermittent deposition through the period between Marine isotope Stage (MIS) 11 and 3 (similar to380 and similar to43 kyr). Most of the growth took place between similar to380 and similar to280 kyr, a period punctuated briefly by a hiatus in deposition through the glacial maximum of MIS 10. Growth was terminated abruptly at 280 kyr just prior to the MIS 8 glacial maximum. With a present-day chamber temperature of 7.5 degreesC, the timing of hiatuses close to these glacial maxima point to freezing conditions at the time. No deposition was recorded through the entirety of MIS 7 and most of MIS 6, whilst two minor growth phases occurred at similar to141-125 and similar to43 kyr. Growth at 141 kyr indicates temperatures >0 degreesC at a time when MIS 6 ice volumes were close to their maximum. High stable carbon isotope (delta(13)C) values (similar to2.8parts per thousand to +3.1parts per thousand) throughout the stalagmite's growth reflect a persistently low input of biogenic CO2, indicating that the steep, barren and alpine-like recharge area of today ha's been in existence for at least the last similar to380 kyr. During MIS 9, the lowest delta(13)C values occur well after maximum interglacial conditions, suggesting a lag in the development of post-glacial soils in this high-altitude karst. The stable oxygen isotope (delta(18)O) trends match the main structural features of the major climate proxy records (SPECMAP, Vostok and Devils Hole), suggesting that the delta(18)O of CC1 has responded to global-scale climate changes, whilst remarkable similarity exists between CC1 delta(18)O and regional sea-surface temperature reconstructions from North Atlantic core ODP980 and southwest Pacific marine core MD97-2120 through the most detailed part of the CC1 record, MIS 9-8. The results suggest that CC1 and other stalagmites from the cave have the potential to capture a long record of regional temperature trends, particularly in regards to the relative severity of Pleistocene glacial stages. (C) 2004 Elsevier B.V. All rights reserved.

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.

Futures dreaming outside and on the margins of the western world

In this article, we challenge the hegemony of western science fiction, arguing that western science fiction is particular even as it claims universality. Its view remains based on ideas of the future as forward time. In contrast, in non-western science fiction the future is seen outside linear terms: as cyclical or spiral, or in terms of ancestors. In addition, western science fiction has focused on the good society as created by technological progress, while non-western science fiction and futures thinking has focused on the fantastic, on the spiritual, on the realization of eupsychia-the perfect self. However, most theorists assert that the non-west has no science fiction, ignoring Asian and Chinese science fiction history, and western science fiction continues to 'other' the non-west as well as those on the margins of the west (African-American woman, for example). Nonetheless, while most western science fiction remains trapped in binary opposites-alien/non-alien; masculine/feminine; insider/outsider-writers from the west's margins are creating texts that contradict tradition and modernity, seeking new ways to transcend difference. Given that the imagination of the future creates the reality of tomorrow, creating new science fictions is not just an issue of textual critique but of opening up possibilities for all our futures.

Managing woodlands for income maximisation in western Queensland, Australia: clearing for grazing versus timber production

Queensland, Australia, has a proud pastoral history; however, the private and social benefits of continued woodland clearing for pasture development are unlikely to be as pronounced as they had been in the past. The environmental benefits of tree retention in and regions of the State are now better appreciated and market opportunities have arisen for the unique timbers of western Queensland. A financial model is developed to facilitate a comparison of the private profitability of small-scale timber production from remnant Acacia woodlands against clearing for pasture development in the Mulga Lands and Desert Uplands bioregions of western Queensland. Four small-scale timber production scenarios, which differ in target markets and the extent of processing (value-adding), are explored within the model. Each scenario is examined for the cases where property rights to the timber are vested with the timber processor, and where royalties are payable. For both cases of resource ownership, at least one scenario generates positive returns from timber production, and exceeds the net farm income per hectare for an average grazing property in the study regions over the period 1989-1990 to 2000-2001. The net present value per hectare of selectively harvesting and processing high-value clearwood from remnant western Queensland woodlands is found to be greater than clearing for grazing. (C) 2003 Elsevier B.V. All rights reserved.

Change in abundance of dugongs in Shark Bay, Ningaloo and Exmouth Gulf, Western Australia: evidence for large-scale migration

The third in a series of five-yearly aerial surveys for dugongs in Shark Bay, Ningaloo Reef and Exmouth Gulf was conducted in July 1999. The first two surveys provided evidence of an apparently stable population of dugongs, with similar to 1000 animals in each of Exmouth Gulf and Ningaloo Reef, and 10000 in Shark Bay. We report estimates of less than 200 for each of Exmouth Gulf and Ningaloo Reef and similar to 14000 for Shark Bay. This is an apparent overall increase in the dugong population over this whole region, but with a distributional shift of animals to the south. The most plausible hypothesis to account for a large component of this apparent population shift is that animals in Exmouth Gulf and Ningaloo Reef moved to Shark Bay, most likely after Tropical Cyclone Vance impacted available dugong forage in the northern habitat. Bias associated with survey estimate methodology, and normal changes in population demographics may also have contributed to the change. The movement of large numbers of dugongs over the scale we suggest has important management implications. First, such habitat-driven shifts in regional abundance will need to be incorporated in assessing the effectiveness of marine protected areas that aim to protect dugongs and their habitat. Second, in circumstances where aerial surveys are used to estimate relative trends in abundance of dugongs, animal movements of the type we propose could lead to errors in interpretation.

A call to arms at the end of history: a discourse-historical analysis of George W. Bush's declaration of war on terror

In this article we take a discourse-historical approach to illustrate the significance of George W Bush's (2001) declaration of a 'war on terror'. We present four exemplary 'call to arms' speeches by Pope Urban 11 (1095), Queen Elizabeth I (1588), Adolf Hitler (1938) and George W Bush (2001) to exemplify the structure, function, and historical significance of such texts in western societies over the last millennium. We identify four generic features that have endured in such texts throughout this period: (i) an appeal to a legitimate power source that is external to the orator, and which is presented as inherently good; (ii) an appeal to the historical importance of the culture in which the discourse is situated; (iii) the construction of a thoroughly evil Other; and (iv) an appeal for unification behind the legitimating external power source. We argue further that such texts typically appear in historical contexts characterized by deep crises in political legitimacy.

Providing treatment for hepatitis C in an Australian district centre

Hepatitis C virus (HCV) poses a major public health problem world wide. The introduction of combined therapy (interferon and ribavirin) and the recent development of pegylated interferon have offered the opportunity to alter the natural history of HCV, potentially reducing morbidity and mortality. Until recently, treatment has been confined to larger Australian cities. This paper describes the establishment of a clinic for the treatment of HCV in a regional Australian city. The facilities of the sexual health clinic were utilised. Factors contributing to the success of the clinic include the specialist nurse, a multidisciplinary approach, and the service model of shared care with general practitioners. The patient population and the outcomes of managing HCV in a regional centre are described. The sustained viral response rate is comparable to the published data from specialist centres.

Peter Brown's The 'rise of western christendom', second edition: A review essay

Peter Brown, perhaps the world's leading scholar in the field of late antiquity, has produced a substantially revised and expanded edition of one of his major books, drawing on the vast volume of recent work. This essay summarizes its central arguments, especially the significance it attributes to developments away from the Mediterranean and to the seventh century, which together allow the topic to be seen in a compelling new light. It applauds the sustained excellence of Brown's prose, as well as his frame of reference and historical imagination. Some questions are raised concerning his deployment of sources, the importance given to the north, the ability to make decisions that people are credited with, and the coming of Islam. That a scholar of Brown's eminence is able to relish and appropriate effectively work that appeared subsequent to the first edition of this book is a tribute to his stature.