Bioeconomic analysis of aquaculture's impact on wild stocks and biodiversity

Anderson theorizes that development of the aquaculture of a species of fish (also captured in an open-access fishery) favours the conservation of its wild stocks, if competitive market conditions prevail. However, this theory is shown to be subject to significant limitations. While this is less so within his model, it is particularly so in an extended one outlined here. The extended model allows for the possibility that aquaculture development can impact negatively on wild stocks thereby shifting the supply curve of the capture fishery, or raise the demand for the fish species subject both to aquaculture and capture. Such development can threaten wild stocks and their biodiversity. While aquaculture development could in principle have no impact on the biodiversity of wild stocks or even raise aquatic biodiversity overall, its impact in the long-term probably will be one of reducing aquatic diversity both in the wild and overall.

Prognostic impact of adenomatous polyposis coil gene expression in osteosarcoma of the extremities

Purpose: To evaluate the impact of adjuvant chemotherapy on the outcome of osteosarcoma of the extremities, and to identify prognostic factors using the expression of adenomatous polyposis coli (APC), cadherin and beta-catenin Wnt-signalling markers. Methods: The clinical, demographic, anatomic and pathological factors including a detailed analysis of the immunohistochemical expression of cadherin, B-catenin and APC were retrospectively examined in 97 patients with osteosarcoma of the extremities (metastatic and non-metastatic at diagnosis), treated with surgery and/or chemotherapy from 1985 to 2000. Results: APC immunoreactivity showed a statistically significant association with age and serum alkaline phosphatase levels (p = 0.025 and p = 0.038). When survival was the end-point of multivariate analysis, race segregated patients with poor survival as did lack of cadherin expression. For overall survival, cadherin immunoreactivity and the interaction between APC expression and response to adjuvant chemotherapy were significant (p = 0.012 and p < 0.001). No significant clinical association was evident with immunohistochemical expression of cadherin, beta-catenin. Conclusion: Lack of expression of cadherin was a significant variable to overall and disease-free survival. Significantly, positive APC immunoreactivity and adjuvant chemotherapy were associated with a favourable treatment response. Studies using newer immunohistochemical markers within the Wnt-signalling pathway may guide the development of more appropriate therapeutic targets for future individualised treatment. (C) 2010 Elsevier Ltd. All rights reserved.

Testing for Market Power in Multiple-Input, Multiple-Output Industries: The Australian Grains and Oilseeds Industries

Recent empirical studies have found significant evidence of departures from competition in the input side of the Australian bread, breakfast cereal and margarine end-product markets. For example, Griffith (2000) found that firms in some parts of the processing and marketing sector exerted market power when purchasing grains and oilseeds from farmers. As noted at the time, this result accorded well with the views of previous regulatory authorities (p.358). In the mid-1990s, the Prices Surveillence Authority (PSA 1994) determined that the markets for products contained in the Breakfast Cereals and Cooking Oils and Fats indexes were "not effectively competitive" (p.14). The PSA consequently maintained price surveillence on the major firms in this product group. The Griffith result is also consistent with the large number of legal judgements against firms in this sector over the past decade for price fixing or other types of non-competitive behaviour. For example, bread manufacturer George Weston was fined twice during 2000 for non-competitive conduct and the ACCC has also recently pursued and won cases against retailer Safeway in grains and oilseeds product lines.