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排序方式: 共有543条查询结果,搜索用时 15 毫秒
41.
Spatial analysis of annual air pollution exposure and mortality 总被引:1,自引:0,他引:1
Scoggins A Kjellstrom T Fisher G Connor J Gimson N 《The Science of the total environment》2004,321(1-3):71-85
The aim of this study was to relate ambient air pollution levels to mortality in Auckland, New Zealand. We used urban airshed modelling and GIS-based techniques to quantify long-term exposure to ambient air pollution levels and associated mortality. After adjusting for age, sex, ethnicity, socio-economic status, and urban/rural domicile there was a 1.3% (95%CI: 1-1.5%) increase in non-external cause mortality, and 1.8% (95%CI: 1.5-2.1%) increase in circulatory and respiratory causes per 1 microg/m(3) increase in annual average NO(2). Based on these exposure-response relationships and applying an annual average threshold of 13 microg/m(3), the average annual (for 1996-1999) number of people estimated to die from non-external causes and circulatory and respiratory causes attributable to air pollution in Auckland is 268 (95% range: 227-310) (3.9% of total all cause deaths) and 203 (95% range: 169-237) (5.9% of total circulatory and respiratory deaths) per year, respectively. The number of attributable deaths found in this study are consistent with a previous New Zealand risk assessment using a different methodology, and is approximately twice the number of people dying from motor vehicle accidents in the region, which is on average (1996-1999) 103 per year. The GIS-based exposure maps identify high exposure areas for policy developers and planners in a simple and realistic manner. Taken together with overseas studies the study provides additional evidence that long-term exposure to poor air quality, even at levels below current standards, is a hazard to the public health. 相似文献
42.
The reaction of equivalent quantities of sec-butyllithium with m-diisopropenylbenzene in cyclohexane and benzene solution in the presence and absence of catalytic amounts of triethylamine, does not yield the diadduct quantitatively. Oligomer formation occurs to varying extents depending on the reaction conditions, and, contrary to claims in the literature, this may not be a good route to a difunctional initiator for anionic polymerization. 相似文献
43.
R.D. DuBois O.G. de Lucio J. Gavin 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(3):397-401
An overview of methods being used at the University of Missouri-Rolla to measure differential ionisation for positron impact is presented. Examples of triply differential electron emission and doubly differential positron scattering and energy loss data are given and contributions to each due to binary and recoil events are discussed. In addition, angular distribution data for electron emission due to double and triple ionisation are presented. 相似文献
44.
Base Resistance of Jacked Pipe Piles in Sand 总被引:1,自引:0,他引:1
The paper presents the results from an experimental program carried out at Trinity College Dublin, in which instrumented model piles were jacked into loose dry sand in a large testing chamber. A number of pile installations were carried out to study the effects of in situ stress, diameter, and wall thickness on the behavior of open-ended piles in sand. These indicated that plug stiffness and capacity may be expressed as simple functions of the cone penetration test end resistance and the incremental filling ratio prior to loading. The magnitude and distribution of shear stresses measured on the inner wall are shown to be compatible with existing experimental data and can be related directly to the stress level, interface friction angle, and dilation of the sand at the pile wall. The data are shown to facilitate a better understanding of the factors controlling plug resistance. 相似文献
45.
Wade L. Hadwen Christine S. Fellows Douglas P. Westhorpe Gavin N. Rees Simon M. Mitrovic Brett Taylor Darren S. Baldwin Ewen Silvester Roger Croome 《河流研究与利用》2010,26(9):1129-1152
Understanding longitudinal trends in the processing of carbon in rivers represents a much conceptualised, but infrequently tested, issue in aquatic ecology. In this study, we conducted concurrent longitudinal examinations of three very different rivers in eastern Australia to determine whether general principles in river functioning exist across broad geographic and hydrologic scales. Specifically, we examined trends in ambient basic water chemistry, nutrient concentrations, dissolved organic carbon (DOC), extracellular enzymes and food web structure and functioning and conducted bioassays to examine the degree to which DOC and nutrients limit heterotrophic bacterial respiration. These parameters revealed striking similarities across all sites. For metazoan communities, stable isotope analysis showed that algal carbon was the dominant basal resource utilised by consumers in all three rivers, suggesting that in‐stream primary producers strongly underpin trophic pathways regardless of the position within a catchment or catchment condition. Analyses of extracellular enzymes revealed that microbial communities are actively utilising DOC at all sites. In fact, heterotrophic microbial respiration was strongly limited by DOC at all sites, with nutrient additions resulting in only relatively minor increases in respiration. Ultimately, this study demonstrates that DOC and algal carbon are critically important drivers of ecosystem processes in Australian riverine ecosystems. Furthermore, across all of our sites and rivers, ambient nutrient concentrations did not influence carbon processing. The consistent longitudinal trends in river function identified in this study provide useful insights for catchment managers and modellers with respect to identifiying key principles that underpin ecosystem functioning in Australian rivers. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
46.
Refinement-closed security properties allow the verification of systems for all possible implementations. Some systems, however, have refinements that do not represent possible implementations. In particular, real instantiations of abstract systems comprising security-critical components surrounded by maximally hostile unrefined components are often characterised only by compositions of refinements of the abstract system's components, rather than all refinements of the abstract system. In this case, refinement-closed security properties that examine multiple behaviours of a system at once can be falsely violated by the presence of inconsistent pairs of behaviour arising from different, incompatible refinements of the system's components.We show how to weaken a class of such properties, which includes both information flow and causation properties, to allow them to be applied to these sorts of abstract systems. The weakened properties ignore all pairs of inconsistent behaviour that would have violated the original property from which they are derived. We also show how to adapt existing automated tests for these properties to allow them to be used to test for their weakened counterparts instead. This enables greater flexibility in the application of these sorts of properties to compositions of nondeterministic components. 相似文献
47.
48.
Sustainability Reporting and Water Resources: a Preliminary Assessment of Embodied Water and Sustainable Mining 总被引:1,自引:0,他引:1
Gavin M. Mudd 《Mine Water and the Environment》2008,27(3):136-144
This paper presents a preliminary compilation and analysis of the water reported to have been consumed by a range of various
mineral commodities and compares it to mine production data. This has been undertaken to assess and quantify the ‘embodied
water’ of mineral products—a key aspect of sustainability (embodied water is the total water required to produce a good or
service). At present, although the use of formal reporting protocols such as the global reporting initiative (GRI) is increasing,
there are still critical weaknesses. Some key aspects to facilitate proper water accounting are not listed in sustainability
reports, including the extent of recycled water used, mine site water inventories, the quality of various waters, and impacts
on water resources. Based on the data compiled, there is wide variation in the water used for different mineral commodities
as well as for the same commodity. There is little evidence for ‘economies of scale’ in base metals and bulk minerals, though
for precious metals (gold, platinum), greater throughput does tend to lead to greater efficiency. For many mines, there is
little evidence of improving efficiency over time, although some mines have made substantive improvements in reducing water
consumed. The grade of ore being processed is clearly critical in understanding the embodied water of minerals, with declining
ore grades leading to an increased chance of higher embodied water in the future. Given that many metals are declining in
average ore grade, the sensitivity of embodied water to ore grade provides a major sustainability challenge for mining generally.
In summary, the embodied water of minerals is clearly significant, and will likely gradually increase in the future, and so
must be more completely accounted for to understand a fundamental aspect of sustainability and mining—that of water resources. 相似文献
49.
Dmitri V. Louzguine-Luzgin Alain R. Yavari Gavin Vaughan Akihisa Inoue 《Intermetallics》2009,17(7):477-480
This paper presents some crystalline structures which can be taken as the approximants of the corresponding metallic glassy phases. Such phases have a clustered structure and preferably (but not strictly necessarily) a large unit cell. Peak intensities of their radial distribution functions (RDFs) must be integrated at a step of about 0.01 nm in order to obtain RDFs similar to those of the corresponding glassy alloys owing to a degree of disorder related to the corresponding glassy structures. 相似文献
50.
Frank R. Cichocki Gavin Chen Jack Zhou Meng Deng 《Materials science & engineering. C, Materials for biological applications》2008,28(3):331-335
Bioabsorbable polyglycolide-co-lactide microtubes have been developed for the continuous delivery of fluid medications directly to an operative site. Studies conducted with radio-opaque solution using porcine models indicated that infusion of fluids in the wound site was rapid and complete. The tissue reaction to the microtube was generally characterized as minimal to mild with complete absorption occurring within 56 days postimplantation. Processing–microstructure-property relationships and bio-degradation characteristics of the microtubes are presented. 相似文献