Wallum on the Nabiac Pleistocene barriers, lower North Coast of New South Wales

Wallum is widespread on coastal dunefields, beach ridge plains and associated sandy flats in northern NSW and southern Queensland. These sand masses contain large aquifers, and the wallum ecosystem is considered to be generally groundwater-dependent. This study describes the floristic composition and environmental relations of wallum on a Pleistocene barrier system at Nabiac (32˚ 09’S 152˚ 26’E), on the lower North Coast of NSW. Despite their minimal elevation and degraded relief, the Nabiac barriers maintain floristic patterns related to topography and hence groundwater relations. Comparative analyses identified the Nabiac wallum as representative of the ecosystem throughout large parts of its range in eastern Australia. The Nabiac wallum and nearby estuarine and alluvial vegetation supports species and communities of conservation significance. A borefield is proposed for development on the Nabiac barriers, thereby providing a valuable opportunity for research into mechanisms of groundwater utilisation by the wallum ecosystem

Wetland biodiversity in coastal New South Wales: the Wallis Lake catchment as a case study

The floristic composition and environmental relations of wetland vegetation in the Wallis Lake catchment (32˚ 09’S; 152˚ 20’E), area 1292 km2, on the lower North Coast of NSW are described. The catchment supports wetlands listed as Endangered Ecological Communities (NSW Threatened Species Conservation Act 1995) and plant species of high conservation value. A methodology of air photo interpretation, site-based sampling (114 quadrats) and landscape differentiation was developed. A total of 393 vascular plant taxa were recorded (including 10% exotics). Wetland vegetation formations and subformations including mangrove forest, swamp sclerophyll forest, wet heathland, chenopod shrubland, tussock grassland, sedgeland and rushland are described using numerical classification. 31 plant species of national or regional conservation significance are identified. Four Endangered Ecological Communities are discussed – Coastal Saltmarsh, Swamp Oak Floodplain Forest, Swamp Sclerophyll Forest on Coastal Floodplains, and Freshwater Wetlands on Coastal Floodplains. A key recommendation is the completion of reliable wetland vegetation and soil landscape mapping for all land tenures in the catchment – to assess wetland condition and conservation significance, and representation in formal conservation reserves, thereby directing future priorities for the protection of wetland biodiversity on both public and private lands. The methodology developed can be applied to the survey and conservation of wetland biodiversity in other parts of coastal NSW

Spin state transition in LaCoO3 by variational cluster approximation

The variational cluster approximation is applied to the calculation of thermodynamical quantities and single-particle spectra of LaCoO3. Trial self-energies and the numerical value of the Luttinger-Ward functional are obtained by exact diagonalization of a CoO6 cluster. The VCA correctly predicts LaCoO3 as a paramagnetic insulator and a gradual and relatively smooth increase of the occupation of high-spin Co3+ ions causes the temperature dependence of entropy and magnetic susceptibility. The single particle spectral function agrees well with experiment, the experimentally observed temperature dependence of photoelectron spectra is reproduced satisfactorily. Remaining discrepancies with experiment highlight the importance of spin orbit coupling and local lattice relaxation.Comment: Revtex file with 10 eps figure

Farm-level Economic Evaluation of Net Feed Efficiency in Australia’s Southern Beef Cattle Production System: A Multi-period Linear Programming Approach

Selection of beef cattle for increased net feed efficiency is a current major focus for research. At present the trait seems to be more apparent in Australia’s southern beef production system which is dominated by mixed farming enterprises. Farm-level evaluation of net feed efficiency should take account of the farming system for which it is proposed along with the dynamic nature of genetic selection. Gross margin, linear programming and multi-period linear programming approaches to evaluation of the trait at the farm-level using a representative farm are compared. Implications of the trait for researchers and beef producers are identifiedfarm-level evaluation, genetic traits, linear programming, Farm Management,

A Northern Tablelands Whole-Farm Linear Program for Economic Evaluation of New Technologies at the Farm-Level

The benefits of evaluating a new technology in a whole-farm context using a linear programming framework are well known. Linear programming allows the joint evaluation of concurrent farm activities, while considering the costs and returns of all enterprises and any resource adjustments imposed by adoption of the technology. This Report provides a rationale for and description of a whole-farm linear programming model that can be used for the economic evaluation of new technologies that are applicable to beef/sheep grazing farms typical of the Northern Tablelands of New South Wales. In this farming system, the whole-farm focus incorporates various aspects of the pasture base, resource constraints and sheep and cattle interactions. An overview of economic tools that are available to assess technologies at the farm level is provided first, listing some of the major benefits and limitations of each of these various techniques. A representative farm for the selected farming system is then developed and a whole-farm linear program based on this representative farm is described in some detail. A series of modelling experiments is undertaken to examine variations of the base model and their impact on the resulting technology evaluation. An example technology, involving the genetic improvement of beef cattle for improved feed efficiency (NFE), is evaluated. The optimal farm plan for a "typical" (single) year is generated, given the objective of maximising farm total gross margin. Three enterprises are selected: 1,108 first-cross ewes, 1,732 Merino wethers and a beef herd of 127 cows producing 18 month old heavy feeder steers (HFS) at 448kg liveweight and excess heifers sold as 9 month old weaners. For this farm plan, the annual operating budget shows a total gross margin for the farm of $86,191. The optimal farm plan for the representative farm is found to be sensitive to relatively small changes in input or output prices and production parameters. Only small improvements in a number of the individual enterprise gross margins would result in them displacing the currently selected enterprises. These results suggest relatively similar profitability levels between these sheep and beef enterprises. This would be anticipated given that all the enterprises described in this report were identified by local experts as being common in the Northern Tablelands. Further, the relatively small differences in enterprise profitability when viewed in a whole farm context also reflect the similar resources that each of the enterprises require, making them readily substitutable. For new technologies that have dynamic attributes, measuring the cashflow over time becomes important. Genetic traits in ruminants that have long biological lags are such technologies. This means that a single-year equilibrium model will be unable to effectively measure the costs of introducing the new technology over time. In the case of the NFE technology in beef cattle, any herd expansion that is possible as a result of the trait is measured by the opportunity cost of heifer sales forgone that are instead retained to increase the breeding herd. These herd dynamics can be represented explicitly within a multi-period version of a whole-farm LP model. The NFE cow enterprise is offered to the model, with the initial sheep enterprises set the same as the base case (1,108 prime lamb producing ewes, 1,732 19-micron Merino wethers). The model again selects 127 HFS producing cows in the first year, but the new optimal farm plan is to invest in the new technology by purchasing NFE-superior bulls in successive years and expanding the cow herd while concurrently decreasing the scale of the Merino wether enterprise. Substitution of Merino wethers for NFE cows occurs up to year 12 after which additional breeding cows are possible from their increasing net feed efficiency alone. There is an increase in cow numbers of 12.6 per cent by year 25, which equates to an improvement in the NPV per breeding cow per year over the base herd of$5.02, using a 5 per cent discount rate. Other experiments reported include adding constraints for fixed costs, family drawings and an overdraft facility; alternate discount rates for the NPV calculations; alternate terminal values for the livestock assets at the end of the simulation period; and a post-optimality risk analysis. This study has highlighted several additional benefits of evaluating a technology in a whole-farm multi-period linear programming framework. First, apart from determining the type and size of the optimal farm enterprise mix and the optimal value of the objective function, whole-farm multi-period linear programming also provides important additional information including shadow costs and prices and constraint slacks, and how they change over time. Shadow costs of activities show how sensitive the optimal farm enterprise mix is to changes in the gross margins of alternate farm activities not included in the current farm plan. The shadow prices for resources indicates how much a farm manager could pay for additional units of a limiting resource, for example, additional labour. Second, in terms of the specific NFE technology examined in this report, it would appear that there may well be regions where such feed efficiencies may be of greater benefit due to particularly large variations in pasture growth patterns throughout the year. The Northern Tablelands with its recognised winter feed deficit may be one such area. This information may be of benefit to researchers in extending the NFE technology to farmers. Third, the deterministic multi-period version of the model highlighted the impact of the inclusion of overhead and capital constraints in the modelling process in determining the potential adoption of a technology by a farm manager. The availability and cost of capital is shown to influence the extent to which the NFE technology may be adopted by an individual farm business. Fourth, from a modelling perspective, the effect of uncertain terminal values and the bearing that they have on measuring the level of adoption of a new technology is an area for further investigation. Finally, the impact of risk was assessed in this study post-optimally by the inclusion of stochastic output prices in the optimal whole farm budgets. This is an area for further research, including the potential of alternate modelling techniques such as MOTAD programming or stochastic dynamic programming. However due to size constraints, such approaches may necessitate trade-offs in terms of the detail of whole-farm models to which they are applied.Research and Development/Tech Change/Emerging Technologies,

Correlated band structure of NiO, CoO and MnO by variational cluster approximation

The variational cluster approximation proposed by Potthoff is applied to the calculation of the single-particle spectral function of the transition metal oxides MnO, CoO and NiO. Trial self-energies and the numerical value of the Luttinger-Ward functional are obtained by exact diagonalization of a TMO6-cluster. The single-particle parameters of this cluster serve as variational parameters to construct a stationary point of the grand potential of the lattice system. The stationary point is found by a crossover procedure which allows to go continuously from an array of disconnected clusters to the lattice system. The self-energy is found to contain irrelevant degrees of freedom which have marginal impact on the grand potential and which need to be excluded to obtain meaningful results. The obtained spectral functions are in good agreement with experimental data.Comment: 14 pages, 17 figure

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. Griffith obtained his results using highly aggregated data and a relatively simple empirical model. In this study we focus on confirming the earlier results by formally testing for competitive behaviour in the Australian grains and oilseeds industries using a more sophisticated empirical model and a less aggregated grains and oilseeds data set. We specify a general duality model of profit maximisation that allows for imperfect competition in both the input and output markets of the grains and oilseeds industries. The model also allows for variable-proportions technologies and can be regarded as a generalisation of several models appearing in the agricultural economics and industrial organisation literatures. Aggregate Australian data taken from the 1996-97 input-output tables are used to define the structure of the relevant industries, and time series data are used implement the model for thirteen grains and oilseeds products handled by seven groups of agents. The model is estimated in a Bayesian econometrics framework. Results are reported in terms of the characteristics of estimated probability distributions for demand and supply elasticities and indexes of market power. Our results suggest that there is a positive probability that: (a) flour and cereal food product manufacturers exert market power when purchasing wheat, barley, oats and triticale; (b) beer and malt manufacturers exert market power when purchasing wheat and barley; and (c) other food product manufacturers exert market power when purchasing wheat, barley, oats and triticale. What is interesting is that each of the transaction nodes where market power is indicated is one where a farm commodity is sold to a processing sector that is, the evidence suggests oligopsonistic behaviour by grains buyers. The wheat and barley industries seem to be especially disadvantaged by this type of market conduct. A related and equally interesting result is that there was no consistent evidence of market power in the downstream nodes of the data set relating to the sales of flour and other cereal foods, or the sale of bread and other bakery products. These transaction points are where legal judgements against suppliers have been made in the recent past. We have stated our results in quite cautious language, as there is much uncertainty surrounding our estimates. This stems partly from the lack of good quality data, so we suggest that one avenue for future research should be improving the collection and integrity of relevant data (especially including the retail and distributive nodes of the various markets).Industrial Organization, Marketing,