Release ofRa from uranium mill tailings by microbial Fe(III) reduction

Uranium mill tailings were anaerobically incubated in the presence of H₂ with Alteromonas putrefaciens, a bacterium known to couple the oxidation of H₂ and organic compounds to the reduction of Fe(III) oxides. There was a direct correlation between the extent of Fe(III) reduction and the accumulation of dissolved²²⁶Ra. In sterile tailings in which Fe(III) was not reduced, there was negligible leaching of²²⁶Ra. The behavior of Ba was similar to that of Ra in inoculated and sterile systems. These results demonstrate that under anaerobic conditions, microbial reduction of Fe(III) may result in the release of dissolved²²⁶Ra from uranium mill tailings.     

Fixed-ammonium in clays associated with crude oils

The association of ammonium (NH₄⁺) silicates with organic-rich sedimentary environments has stimulated interest in the chemical cycle of N, and its possible application as an indicator of in situ organic maturation reactions or crude oil migration. Fixed-NH₄ in clay minerals was determined from three hydrocarbon occurrences of similar depositional environment but different ages, depth and thermal maturity, to determine whether anomalously high NH₄-substitution occurs near mature hydrocarbons. Results show higher fixed-NH₄ concentrations in marginally mature mudstones than in immature sediments. The highest fixed-NH₄ concentrations were found in clays from sandstone reservoirs containing migrated crude oil.Fixed-NH₄ in clays from Holocene oil seep sediments in the Gulf of Mexico continental slope, offshore Louisiana, averages 0.08 wt % and increases with depth in shallow cores (420 cm), reflecting an early diagenetic trend that is apparently not influenced by migrating crude oil. Programmed pyrolysis shows that the sediments are thermally immature (av.T_max = 419°C). High Hydrogen Index values (av.= 359mg/g) are the result of biodegraded crude oil, and a high Oxygen Index (av.= 182mg/g) reflects the presence of authigenic carbonate.Fixed-NH₄ averages 0.16 wt % in Wilcox Group (Eocene) mudstones enclosing two sandstone reservoirs at Fordoche Field, onshore Louisiana. In comparison to these mudstones, anomalously high NH₄-fixation appears to occur in reservoir clay minerals. Pyrolysis shows that the sediments are marginally mature for crude oil generation (av.T_max = 432°C). Average Hydrogen Index (187 mg/g) and Oxygen Index values (75 mg/g) are consistent with oil-prone Type II and Type III kerogen. Increased pyrolysis Production Index values and solvent extraction shows the presence of migrated crude oil. This suggests that a reaction which releases NH₃ during crude oil generation or migration is recorded byNH₄⁺ substitution in clays.Fixed-NH₄ and total organic carbon (TOC) at Fordoche Field show no statistically significant correlation, suggesting that NH₄⁺ substitution in clay minerals is not simply related to the amount of organic matter in the section, but is also influenced by the presence of crude oil. Once NH₄⁺ has been fixed in clays, it is a more stable hydrocarbon proximity indicator than pore fluid tracers, because it is less influenced by later chemical or geological changes.     

The first rural women's network in New South Wales: seventy years of the country women's association

The Country Women's Association of NSW (CWA) is the main voice of rural women in the state. It has been the biggest women's organisation in NSW until very recently. Its significant contribution to rural community development has been overlooked. After its foundation in 1922, the CWA established a widespread women's network, as well as many facilities for women and children. The necessary fund‐raising activities required the organisation of regular social activities in country towns. The CWA has always affirmed women's traditional gender roles, and it has never challenged the male hegemony typical of rural Australia. By contributing to the improvement of rural conditions, to the stability of family life and to local social activities, the CWA has helped to develop the rural economy as well as local and national identity. It has helped women put down roots in country areas. Its future role needs to be defined in the context of the difficult economic situation, and of the changes in gender roles, in rural NSW.     

International migration and health: Sickle cell and thalassaemia health care in the United Kingdom

Human migration has contributed to the redistribution of diseases from regions where they were endemic, thereby creating new areas where the task of control and management has become necessary. This is the case with respect to the major haemoglobinopathies — sickle cell anaemia and thalassaemia — in the United Kingdom since World War II. On the one hand, the great cultural diversity of the immigrant population presents an important challenge in delivering health care to the populations at risk of the diseases. On the other hand, the spatial concentration of these populations is one of the greatest advantages in the management of the disorders, since access to centrally located services can be optimized.The case of health care relating to the major haemoglobinopathies in the United Kingdom raises practical and theoretical questions about the most effective health care delivery models for ethnic minority needs. In turn, this issue has important implications for decisions concerning national and regional budgetary priorities in the health service and the position of minority medicine in the allocation of resources.     

A simple cleaning procedure for improvement of training site statistics

For improving the effectiveness of supervised training, a simple cleaning procedure which operates by selectively dropping training site pixels based on the Mahalanobis distance and class probability has been proposed. The method is iterative and takes into account the spectral overlap in all image bands with all the user specified classes. The procedure results in greater classification accuracy with narrower confidence interval. On the test data, Bhattacharrya distance measure of class separability unproved front an average value of 1.9373 to 1.9797 with a maximum change for a class pair from 1.2671 to 1.9052. The overall classification accuracy increased from 94.74 ±0.64 to 99.63 ± 0.19.     

Size selection of Atlantic rangia clams,Rangia cuneata,by blue crabs,Callinectes sapidus

Male blue crabsCallinectes sapidus Rathbun were allowed to forage on six size classes of the Atlantic rangia clam,Rangia cuneata (Sowerby), in laboratory squaria under conditions of restricted or unrestricted prey size availability. Prey profitability (energy gained divided by handling time) decreased as prey size increased. Crabs preferred smaller clams (1–2 cm long, then 2–3 cm long), as predicted by an energy maximization model. Under conditions of restricted prey sizes (nonreplacement experiments), when the smaller clams were no longer available, crabs tended to choose progressively larger clams. Crabs did not exhibit selective feeding behavior among clams larger than 3 cm long. For the range of crab sizes tested (71–167 mm carapace width), there was no correlation between crab carapace width and the mean clam size that was eaten.     

Design of tunnel linings in a creeping rock

Summary The effect of long term rock deformation on lining pressure is considered using different concepts of rock behaviour. These include the conventional characteristic-line or convergence-confinement method, modified to allow for rock ageing, and lining-rock interaction methods using models of linear-viscoelastic, linear-elastic linear viscous, and linear elastic non-linear viscous rock behaviour. Calculations of lining pressures show that the former tends to underestimate, compared with the latter.This paper was presented at the 28th US Symposium on Rock Mechanics in Tucson, Arizona, July 1987.     

Searching for sustainability in aquaculture: An investigation into the economic prospects for an integrated salmon–mussel production system

The pollution effects of cage aquaculture represent an external cost to society, and the challenge for environmental economists has been to estimate the magnitude of these costs and to suggest ways in which they can be mitigated or ‘internalised’. One possible mitigation strategy involves the development of integrated production systems based on polyculture, and this paper examines the financial viability of such a system that integrates the farming of salmon and mussels. The results demonstrate the commercial potential of an integrated salmon–mussel production system under present market conditions, but highlight the critical role played by future price trends.