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471.
The Peto test is the standard method of analysis used in carcinogenicity studies to compare tumor incidence in groups of animals. It assumes that tumors are either instantly fatal or have no effect on mortality and requires a judgement of the lethality of each tumor. To avoid this requirement, parametric multi-state models have been proposed. In addition these allow estimation of tumor onset and mortality rates. This paper considers two such models and presents a modification. It is shown that the modified models provide a better fit to carcinogenicity data and simulated data are used to show that the modified models provide a modest increase in test power relative to the Peto test. 相似文献
472.
Frøydis Gillund Anne Ingeborg Myhr 《Journal of Agricultural and Environmental Ethics》2010,23(6):527-550
The future of salmon aquaculture depends on the adoption of alternative feed resources in order to reduce the need for fish
meal and fish oil. This may include resources such as species from lower trophic levels, by-products and by-catch from fisheries
and aquaculture, animal by-products, plants, genetically modified (GM) plants, nutritionally enhanced GM plants and products
from microorganisms and GM microorganisms. Here, we report on a deliberative assessment of these alternative feed resources,
involving 18 participants from different interest groups within Norwegian salmon aquaculture. The participants defined a broad
range of appraisal criteria concerning health and welfare issues, economical issues, environmental issues, and knowledge and
social issues. A number of uncertainties, in the form of incomplete knowledge, diverging opinions, and context specific factors
were identified when the participants evaluated the alternatives. Our findings support the need for more research on the suitability
of alternative feed resources for farmed salmon. Additionally, the study underlines the importance of facilitating deliberative
assessments in order to map the plurality of perspectives and explore qualitative aspects of uncertainty. Such initiatives
improve the information base upon which decisions on future feed resources for farmed salmon are made. 相似文献
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476.
Ardavan Mohajer Anne Trémier Suzelle Barrington José Martinez Cecile Teglia Marco Carone 《Waste management (New York, N.Y.)》2009,29(8):2257-2264
The wide range of optimal values reported for the physical parameters of compost mixtures suggest that their interactive relationships should be investigated. The objective of this study was to examine the microbial O2 uptake rate (OUR) in 16 sludge waste recipes, offering a range of moisture content (MC), waste/bulking agent (W/BA) ratio and BA particle size levels determined using a central composite experimental design. The 3 kg samples were maintained at a constant temperature and aeration rate for 28 days, during which a respirometer recorded O2 uptake to provide a measure of microbial activity and biodegradability. The cumulative O2 consumption after 14 and 28 days was found to be significantly influenced by MC, W/BA ratio, BA particle size and the interaction between MC and W/BA ratio (p < 0.05). Using multivariate regression analysis, the experimental data was used to generate a model with good predictive ability for cumulative O2 consumption after 28 days as a function of the significant physical variables (R2 = 0.84). The prediction of O2 uptake by the model depended highly on the interaction between MC and W/BA ratio. A MC outside of the traditional 50–60% (wet basis) range still resulted in a high level of microbial O2 uptake as long as the W/BA ratio was adjusted to maintain a suitable O2 exchange in the sample. The evolution of OUR in the samples was also investigated, uncovering strong associations between short and long-term respirometric indices, such as peak OUR and cumulative O2 consumption (p < 0.005). Combining peak OUR data with cumulative O2 consumption after 14 days allowed for accurate predictions of cumulative O2 after 28 days of aeration (R2 = 0.96), implying that future studies need only run trials up to 14 days to evaluate the overall O2 consumption or biodegradability of similar sludge mixtures. 相似文献
477.
Terry L Tudor Anne C Woolridge Margaret P Bates Paul S Phillips Sharon Butler Keith Jones 《Waste management & research》2008,26(3):233-240
Changes in environmental legislation and standards governing healthcare waste, such as the Hazardous Waste Regulations are expected to have a significant impact on healthcare waste quantities and costs in England and Wales. This paper presents findings from two award winning case study organizations, the Cardiff and Vale NHS Trust and the Cornwall NHS Trust on 'systems' they have employed for minimizing waste. The results suggest the need for the development and implementation of a holistic range of systems in order to develop best practice, including waste minimization strategies, key performance indicators, and staff training and awareness. The implications for the sharing of best practice from the two case studies are also discussed. 相似文献
478.
Anne Pedersen 《Waste management & research》2008,26(1):111-114
During 2006 the CDM market in Malaysia became established and by December 2007 a total of 20 Malaysian projects had registered with the CDM Executive Board. The Kyoto Protocol defines the Annex 1 countries, as countries that are obliged to reduce their greenhouse gas (GHG) emissions and the clean development mechanism (CDM) allows Annex 1 countries to develop projects, which contribute to emission reduction, in non-Annex 1 (developing) countries. Currently, two projects have been corrected due to request for review and there is one project for which review is requested. Two projects have been rejected by the Executive Board. The broad knowledge of CDM in Malaysia and the number of successful projects are partly due to the well-functioning CDM institutional framework in Malaysia. As an illustration this article focuses on a Malaysian-Danish project and describes the implementation of CDM in Malaysia and refers to this specific project. The project was registered with the CDM Executive Board in May 2007 and is a methane avoidance project in which methane is captured from a landfill and used to generate electricity. 相似文献
479.
O. Anne E. Rasa 《Behavioral ecology and sociobiology》1998,43(2):105-113
Parastizopus armaticeps is a nocturnal subsocial detritivorous desert tenebrionid that produces very few offspring per brood. The two environmental
factors that constrain reproduction, rapid sand desiccation rate and food scarcity, are countered by biparental effort. Males
dig and extend breeding burrows, maintaining their moisture level; females forage on the surface at night for high-quality
detritus, the larval food. This was shown to be a scarce and unpredictable resource for which there is high competition. When
food was supplemented in a field experiment, offspring number and survivorship doubled and burrow failure due to desiccation
dropped from approximately half, the typical failure rate for unsupplemented burrows, to zero. Food supplementation did not,
however, increase larval foodstore size and there was no difference in the size of the offspring produced. Supplemented females
reallocated their time, foraging less and digging more with the male. This change in maternal behaviour patterns resulted
in deeper burrows which remained moist longer, thus extending the larval production period. Female foraging efficiency, particularly
food retrieval speed, determined how much time females could allocate to digging, consequently increasing the reproductive
success of the pair. Burrow depth and sand moisture level at the burrow base were the major correlates of reproductive success,
but the scarcity and unpredictability of high-quality food on the surface and the competition for this resource influenced
the number of offspring indirectly through their effect on female behaviour.
Received: 29 November 1996 / Accepted after revision: 7 December 1997 相似文献
480.
PD Dr. Rolf Altenburger Dr. Dana Kühnel Martin Bittens Dr. Birgit Daus Dr. Werner Brack Dr. Florian Centler Prof. Dr. Hauke Harms Dr. Martin Thullner Dr. Lukas Y. Wick Prof. Dr. Kai-Uwe Goss Prof. Dr. Frank-Dieter Kopinke Dr. Katrin Mackenzie Dr. Anja Miltner PD Dr. Matthias Liess Dr. Rainer Wennrich Dr. Anne E. Berns PD Dr. Peter Burauel 《Environmental Sciences Europe》2010,22(4):502-506