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L. Richard Little André E. Punt Bruce D. Mapstone Gavin A. Begg Barry Goldman Ashley J. Williams 《Ecological modelling》2009
Individual transferable quotas (ITQs) are increasingly seen as a way to make fisheries more profitable and halt over-capitalisation. ITQs allocate to users of a resource a share of a total allowable catch (TAC) which they are free to use, lease, or sell. We outline an approach to modelling the effect of an ITQ system in a multi-species, multi-sector fishery and apply it to the Coral Reef Fin Fish Fishery (CRFFF) in Queensland, Australia. An ITQ model, based on the assumption that operators seek to maximize profits, simulates the use of tradeable quota units by operators in the fishery, taking account of the initial quota allocation to operators, seasonal fish prices and individual operator variable costs, their fishing efficiency and experience, and constraints on vessel movements. Rationalization of the fishery is predicted to occur under an ITQ system for the CRFFF, which will lead to reductions in effort, increases in profits, and changes over time in quota prices. The ecological consequences of transferable quota in the multi-species fishery are seen in the catch and discard levels of the less profitable species, even though a TAC was set. This had flow-on effects on biomass. For example, simulations showed that the TAC for the primary target species, coral trout, was used more fully than that for a less valuable target species, red throat emperor, and that this was achieved through increased discarding of red throat emperor. Catches of both coral trout and red throat emperor that were derived from the model were higher than those recently observed in the fishery. The effort predicted by the model, however, closely approximated the actual effort observed in the fishery following implementation of ITQ management. 相似文献
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In 1997 a workshop was held on the subject of how to cope with accelerating technologies. These are industries such as aviation, air traffic control and biotechnology, amongst others, where the rate of technological development is significant. A number of papers were presented from a range of viewpoints and in a variety of different industrial contexts. The papers ranged from theoretical models to help understand the process of acceleration and its impact on organisational learning, to practical analyses of future potential risks in specific accelerating industries such as air traffic control. The aim of the papers and the workshop as a whole was to provide insight into the problems associated with accelerating technologies, and thereby derive measures to control or cope with such acceleration. The problems arising from acceleration, as predicted by the theoretical models and evidenced by experiences in accelerating industries (e.g. aviation) are manifold. Two examples of particular problems are unforeseen risks in an industry (a lack of forward vision), and a failure to learn adequately (i.e. in time) from incidents occurring in an organisation (a lack of constructive hindsight). There is also an incipient danger of society being driven by technology rather than being led by social needs. Even if each technology ultimately becomes ‘ultra-safe’, it will nevertheless have its own ‘event horizon’, limiting useful further progress. Each of the papers from the workshop is summarised and integrated into a three-part synopsis of the workshop. This covers the context of accelerating technologies, modelling their impacts, and deriving coping strategies. Four of the papers are included in their entirety as separate papers in their own right in this special issue of Safety Science. 相似文献
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We compared measures of ecosystem state across six adjacent land-tenure groups in the intact tropical savanna landscapes of
northern Australia. Tenure groups include two managed by Aboriginal owners, two national parks, a cluster of pastoral leases,
and a military training area. This information is of relevance to the debate about the role of indigenous lands in the Australian
conservation estate. The timing and frequency of fire was determined by satellite imagery; the biomass and composition of
the herb-layer and the abundance of large feral herbivores by field surveys; and weediness by analysis of a Herbarium database.
European tenures varied greatly in fire frequencies but were consistently burnt earlier in the dry season than the two Aboriginal
tenures, the latter having intermediate fire frequencies. Weeds were more frequent in the European tenures, whilst feral animals
were most abundant in the Aboriginal tenures. This variation strongly implies a signature of current management and/or recent
environmental history. We identify indices suitable for monitoring of management outcomes in an extensive and sparsely populated
landscape. Aboriginal land offers a unique opportunity for the conservation of biodiversity through the maintenance of traditional
fire regimes. However, without financial support, traditional practices may prove unsustainable both economically and because
exotic weeds and feral animals will alter fire regimes. An additional return on investment in Aboriginal land management is
likely to be improved livelihoods and health outcomes for these disadvantaged communities. 相似文献
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Goebes MD Hildemann LM Kujundzic E Hernandez M 《Journal of environmental monitoring : JEM》2007,9(6):599-609
Aspergillus is a genus of mold that has strong indoor sources, including several species capable of acting as opportunistic pathogens. Previous studies suggest that Aspergillus could serve as an indicator for abnormal mold growth or moisture, making it an important genus for environmental monitoring. Here, a quantitative polymerase chain reaction (qPCR, or real-time PCR) assay is presented for Aspergillus. The assay shows good specificity for the genus, detecting all Aspergillus species tested, although a few non-Aspergillus species are also amplified. Sensitivity testing demonstrates that DNA representing one conidium can be detected. A validation study compared qPCR results against direct microscopy counts using A. fumigatus conidia aerosolized into a laboratory chamber. The assay was then used to quantify Aspergillus in indoor air samples, demonstrating its utility for environmental monitoring. Analysis of a small number of clinical sputum samples showed complete agreement with culturing results. 相似文献
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This paper reviews the evolution of energy use in Sweden since the early 1970s to shed light on the future, with emphasis on the role of energy efficiency. Between 1973 and 1989 improvements in end-use energy efficiency saved 8% of Sweden's primary energy use and 24% of Sweden's delivered energy use. These savings were concentrated in the residential and manufacturing sectors, with important savings also occurring in air travel and the heating of commercial buildings. Despite these accomplishments, we found that Sweden was well behind Denmark, FRGermany, Japan and the USA in energy savings during this period. At the beginning of the 1990s Sweden exhibited one of the most energy intensive economic structures in the OECD. Sweden now faces many dilemmas that will influence future energy use: the role of nuclear power, pricing and taxation policies for fuels and electricity, the future of subsidies for housing and travel, the role of Sweden's energy intensive exports, and indeed the very lifestyle of the Swedes. 相似文献