Antagonism by DDT of the effect of valinomycin on a synthetic membrane     

B D Hilton  R D O'Brien 《Science (New York, N.Y.)》1970,168(933):841-843

The potassium conductance which is induced by 10(-6) molar valinomycin in a lecithin-decane membrane is reversed by 3 x 10(-6) molar DDT. Membranes not treated with valinomycin are not affected by DDT. This blockade of potassium conductance parallels the effect of DDT on axonic conduction. Dieldrin and lindane, whose physiological actions are in some ways like those of DDT, do not affect valinomycin-induced conductance of lecithin-decane membranes.  相似文献   

Adoption of sustainable irrigation management practices by stone and pome fruit growers in the Goulburn/Murray Valleys, Australia     

Anne-Maree Boland  Denise Bewsell  Geoff Kaine 《Irrigation Science》2006,24(2):137-145

The management of water resources by orchards in the south-eastern region of Australia is an increasingly important policy issue, especially given the low water allocations and concerns about salinity in recent years. Optimal management for economic and environmental sustainability can be described as best management practice (BMP). A project was developed to run an extension program, which aimed to achieve behavioural change among orchardists through the adoption of irrigation BMPs and benchmarks. The effectiveness of the extension program was evaluated and the drivers for adoption assessed. In the first stage of the project both BMPs and benchmarks were determined for irrigation management. A survey of 200 growers showed no relationship between yield and irrigation system or irrigation volume suggesting that increased yields were not a key driver for adoption of sustainable irrigation practices. Stage two of the project involved undertaking an extension program aimed to facilitate the adoption of BMPs and benchmarks and incorporated a suite of activities to meet the learning needs of a diversity of participants (40 growers). The program was effective in establishing behavioural change for many of the growers involved; however, it was resource intensive requiring significant one-on-one input. Stage three aimed to analyse the key drivers for adoption of sustainable irrigation practices for the whole of the stone and pome fruit industry in south-eastern Australia using market research. The study determined that water use efficiency was not a key driver for adoption of sustainable irrigation practices (micro irrigation and soil moisture monitoring) and adoption was generally not limited by lack of knowledge. Groups of growers were identified where extension programs could be effective by focussing on specific information e.g. redevelopment of orchard. Other groups had no need and/or ability to change unless the external operating environment was to change e.g. regulation, access to pressurised water. The voluntary adoption of more sustainable irrigation practices will probably require extensive resources using one-on-one methodology. The extension program should not focus on the broader social objective of improved water use efficiency but promote other potential benefits (e.g. labour saving, redevelopment of production systems, management flexibility) with targeted messages for specific groups.  相似文献   

Evaluation of pheromone release from commercial mating disruption dispensers     

Tomaszewska E  Hebert VR  Brunner JF  Jones VP  Doerr M  Hilton R 《Journal of agricultural and food chemistry》2005,53(7):2399-2405

Pome fruit growers and crop consultants have expressed concerns about the seasonal release performance of commercial codling moth mating disruption dispenser products. Because of these concerns, we developed a laboratory flow-through volatile collection system (VCS) for measuring the volatile release of the codling moth sex pheromone, codlemone, from commercially available hand-applied dispensers. Under controlled air-flow and temperature conditions, the released vapor was trapped onto a polyurethane foam adsorbent followed by solvent extraction, solvent reduction, and GC/MS determination. Method recovery and breakthrough validations were performed to demonstrate system reliability before determining codlemone release from commercial dispensers field-aged over 140 days. The volatile collection was carried out in a consistent manner among five dispenser types most commonly used by growers, so that direct comparison of performance could be made. The comparison showed differences in the amount of pheromone released and in the patterns of release throughout the season between dispenser types. The variation in release performance demonstrates the need for routine evaluation of commercially marketed mating disruption dispensers. We believe that the simple and cost-effective volatile collection system can assist pheromone dispenser manufacturers in determining seasonal dispenser performance before new products are introduced into the commercial market and in rapidly verifying dispenser release when field-aged dispenser efficacy is in question.  相似文献   

Nitrate leaching from short-rotation coppice   总被引：1，自引：0，他引：1  

G. Goodlass    M. Green    B. Hilton  & S. McDonough   《Soil Use and Management》2007,23(2):178-184

In the UK, short‐rotation coppice (SRC) is expected to become a significant source of ‘bio‐energy’ over the next few years. Thus, it is important to establish how nitrate leaching losses compare with conventional arable cropping, especially if SRC is grown in Nitrate Vulnerable Zones. Nitrate leaching was measured using porous ceramic cups in each of the three phases in the lifespan of SRC, establishment, harvest and removal and was compared with conventional arable cropping. Nitrogen concentrations were increased in drainage water as soon as the crop cover was destroyed to plant the SRC (peak 70 mg L^?1 nitrate‐N) and increased further (peak 134 mg L^?1 nitrate‐N) on cultivation. Once the coppice crop was established, concentrations returned to a smaller level (average 18 mg L^?1 nitrate‐N). Concentrations were not affected by the harvesting operation, and annual applications of nitrogen (40, 60 and 100 kg ha^?1 N in the first, second and third years, respectively) had little effect. By contrast, concentrations in the arable rotation showed a regular pattern of increase in the autumn, and the average peak value over the 4 years was 54 mg L^?1 nitrate‐N. When the SRC was ‘grubbed up’ and roots removed, the soil disturbance resulted in a flush of mineralization which, combined with a lack of crop cover, led to increased nitrate‐N in leachate (peak 67 mg L^?1 nitrate‐N). In a normal life‐span of SRC (15–30 years), the relatively large nitrate losses on establishment and at final grubbing up would be offset by small losses during the productive harvest phase, especially when compared with results under the arable rotation.  相似文献   

Soil pH preferences and the influences of soil type and temperature on the survival and growth of Aporrectodea longa (Lumbricidae): The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002     

Geoff H. Baker  Wendy A. Whitby 《Pedobiologia》2003,47(5-6):745-753

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Influences of native (Megascolecidae) and exotic (Lumbricidae) earthworms on ryegrass production in acidic pasture soils from south-eastern Australia: The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002     

Geoff H. Baker  K.Yin Chan  Katrina Munro 《Pedobiologia》2003,47(5-6):830-834

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Metabolite profiling of tomato (Lycopersicon esculentum) using 1H NMR spectroscopy as a tool to detect potential unintended effects following a genetic modification   总被引：5，自引：0，他引：5  

Le Gall G  Colquhoun IJ  Davis AL  Collins GJ  Verhoeyen ME 《Journal of agricultural and food chemistry》2003,51(9):2447-2456

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The conservation status of the spectacled petrel Procellaria conspicillata     

Peter G. Ryan  Clifford Dorse  Geoff M. Hilton 《Biological conservation》2006,131(4):575-583

The spectacled petrel Procellaria conspicillata is listed as critically endangered due to its small population size and ongoing mortality on long-lines. Spectacled petrels were counted in 2004, repeating a census made in 1999 at their sole breeding locality, Inaccessible Island. The 2004 survey took place earlier in the breeding season than the previous count, allowing for more robust estimates of burrow occupancy. During early incubation, birds responded to call playback at 69% of burrow entrances, but birds in at least 8% of burrows remained silent. Birds in shallow burrows were less likely to respond to playback than were those in deep burrows. Two repeat trials at 100 marked nests showed that at least 61% of apparently ‘unoccupied’ burrows were occupied on subsequent checks, resulting in an overall occupancy estimate of 91%. Occupancy was equally high in peripheral colonies. The apparent spatial extent of colonies increased slightly from 1999, and the estimate of total burrow numbers increased by 50%, from 5900 burrows in 1999 to 8900 in 2004. Validation surveys indicated that burrow numbers were underestimated (84 ± 3%) to the same extent as that in 1999 (85 ± 4%), and repeat checks of one colony where all nests were marked showed that even careful counts underestimated actual numbers of burrows by up to 10%. This suggests there are some 11-12,000 burrows, and assuming 90% occupancy, the adult population is likely to be at least 20,000 birds. The population has increased over the last five years, continuing the apparent recovery from a very small population size in the early 20th century. Despite this increase, demographic models indicate that the population remains at risk from relatively small increases in mortality, if mortality is determined primarily by fishing effort. Mitigation of long-line mortality remains the key conservation goal for this species.  相似文献   

Energy     

Geoff Bertram 《Asia Pacific viewpoint》2001,42(1):115-131

The 1990s was a decade in which radical institutional restructuring was imposed from above on an energy economy which was in a stage of stable maturity following half a century of rapid development. The key plank in the reforms was the withdrawal of the state from ownership of energy production where possible (natural gas and parts of electricity), and from any non‐commercial philosophy in relation to the electricity and coal enterprises which remained state‐owned. Regulation of natural monopoly elements (pipelines, transmission and distribution lines, processing plants) was virtually eliminated under the rubric of ‘light‐handed regulation’, and the scheduling of electricity generators was moved from a planned to a market system. Underlying real trends in energy intensity, production and use were unaffected by the reforms, and the expected efficiency gains which had motivated reform were not in evidence by the end of the decade.  相似文献   

New Naturalist: The Broads,by Brian Moss. Collins,London, UK, 2001, 392pp. Price £34.99 (hardback), ISBN 000 220163 1; £19.99 (paperback), ISBN 000712410 4.     

Geoff Phillips 《水产资源保护:海洋与淡水生态系统》2003,13(3):279-280

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