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271.
船舶对区域大气污染的贡献备受关注.为控制船舶大气污染物排放,推进我国靠港船舶转用低硫油,以珠江口湾区为案例区,在利用统计分析法确定船舶辅机功率、靠港时间等关键参数的基础上,采用燃料动力法估算靠港船舶转用低硫油的经济成本与环境效益.结果表明:①珠江口湾区靠港船舶燃油消耗量大,2015年珠江口湾区船舶在靠港期间的总耗油量达31.35×104 t.②珠江口湾区靠港船舶转用低硫油的环境效益显著.2015年珠江口湾区大于3 000 DWT(载重吨)的靠港船舶转用w(S)(硫含量)为0.5%的燃油时,PM10、PM2.5、NOx、SOx排放量分别减少792.8、729.1、566.3、6 979.9 t;转用w(S)为0.1%的燃油时,PM10、PM2.5、NOx、SOx排放量分别减少835.3、792.8、1769.7、8 155.0 t.③靠港船舶转用低硫油会增加船东的成本.2015年珠江口湾区大于3 000 DWT靠港船舶都转用w(S)为0.1%的燃料油,因燃油价格差导致的额外成本为2.29×108元.在目前航运经济不景气的背景下,可通过财政补贴方式鼓励船东转用低硫油.参照深圳对靠港船舶转用低硫油的补贴政策,2015年大于3 000 DWT靠港船舶转用w(S)为0.5%的燃油时需补贴资金1.71×108元,转用w(S)为0.1%的燃油时需补贴资金2.29×108元.研究显示,靠港船舶转用低硫油能显著降低大气污染物排放,但转用低硫油需要船东承担一定的经济成本,政府应通过补贴等激励方式,逐步推进靠港船舶转用低硫油. 相似文献
272.
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274.
Marshall Flug Robert H. Montgomeiy 《Journal of the American Water Resources Association》1988,24(5):1073-1081
ABSTRACT: A basic problem in the management of rivers has been how to balance the tradeoffs between instream and out-of-stream uses. Traditionally, the problem has been addressed by optimizing the economic benefits of flow diversions and regulated releases with instream uses as a flow constraint. An alternative method is to model the effect different river flows have on various recreational uses (e.g., boating, fishing) and then use the results as an additional function or piece of information to determine river project operations and benefits. A methodology that is based on multiobjective decision theory and that relates instream recreational preferences to river flow is proposed. The methodology consists of determining, standardizing, and combining recreational benefit functions, and incorporating potential sources of uncertainty into an estimate of total instream benefits. Thus different types of flow patterns, resulting from reservoir regulation (out-of-stream water uses), can be analyzed to determine their potential instream impact. The methodology is applied to the New River Gorge, West Virginia, which has been designated as a National River. 相似文献
275.
神龙公司坚持开展"清洁无害工厂"创建活动,积极推行清洁生产,取得良好环境效益,经济生产创历史最好水平。 相似文献
276.
We compared the medical and financial cost-effectiveness of prenatal serum screening for Down's syndrome using maternal age, serum alpha-fetoprotein and human chorionic gonadotrophin with and without the use of unconjugated oestriol. The use of unconjugated oestriol is medically more cost-effective than screening without it at all levels of detection. The actual performance depends on whether gestational age is estimated using ‘dates’ or an ultrasound scan. At a detection rate of 60 per cent, the proportion of unaffected fetal losses per case diagnosed at amniocentesis is about 22 per cent less if gestational age is estimated using dates (time since the first day of the last menstrual period) and about 47 per cent less if it is based on an ultrasound scan examination. At this detection rate, the inclusion of unconjugated oestriol increases costs by about £2k per case diagnosed (£36k instead of £34k) if gestational age is estimated using dates, but it is no more expensive if gestational age is measured from an ultrasound scan examination (indeed, it is more cost-effective at detection rates above 60 per cent). Since there is little change in the financial cost with the inclusion of unconjugated oestriol, for the improved medical performance of screening, it is worthwhile including it in the screening test. 相似文献
277.
油母页岩干馏煤气脱硫工艺的选择 总被引:1,自引:0,他引:1
何红梅 《辽宁城乡环境科技》2006,26(2):33-34,42
针对页岩炼油厂生产工艺和二氧化硫的产生量,提出了煤气干法和湿法脱硫工艺,并对这两种工艺在原理和适用性方面进行了对比,认为湿法脱硫更适合于该厂的实际情况,经对湿法脱硫的投资费用进行的估算结果显示,该厂采用湿法脱硫技术将会带来明显的环境效益和社会效益。 相似文献
278.
A. J. Moore 《Behavioral ecology and sociobiology》1994,35(4):235-241
The adaptive nature of female mate choice remains one of the most contentious issues in the study of sexual selection. Here, I provide evidence that mate choice by females of the ovoviviparous cockroach Nauphoeta cinerea influences the rate at which offspring develop and provides both direct and indirect benefits to the female. Males that are more attractive to females produce offspring with shorter development times than less preferred males. Development time is heritable and apparently unconstrained by antagonistic pleiotropy. Male attractiveness and rate of offspring development are genetically correlated. Offspring gain an indirect benefit from their mother's mate choice because, on average, individuals that hatch faster reach sexual maturity more quickly. Females that discriminate among males gain a direct benefit because N. cinerea is ovoviviparous and the time between clutches is decreased by producing offspring with shorter development. In addition to providing evidence for beneficial consequences of mate choice, this study highlights how genetic data provide insights into the process of sexual selection not gained in a purely phenotypic study.Communicated by P. Pamilo 相似文献
279.
According to indicator models of sexual selection, mates may obtain indirect, i.e. genetic, benefits from choosing partners indicating high overall genetic quality by honest signals. In the scorpionfly Panorpa vulgaris, both sexes show mating preferences on the basis of the condition of the potential partners. Females prefer males that produce nuptial gifts (i.e. salivary secretions) during copulation, while males invest more nuptial gifts in females of high nutritional status. Both characters, males' ability to produce nuptial gifts and high nutritional status of females, are known to be reliable indicators of foraging ability. Thus, besides possible direct benefits, both sexes might also obtain indirect benefits in terms of “good foraging genes” by their choice and thereby increase the fitness of their offspring. A prerequisite for this possibility is the heritability of the respective trait. In the present study, we estimated the repeatability and the heritability of foraging ability. Our results indicate (1) a significant repeatability of individual foraging efficiencies in males and females and (2) a heritable component of this trait by a significant parent–offspring regression. These findings suggest that genetic benefits in terms of increased offspring foraging ability might contribute to selection for mating preferences in both sexes. 相似文献
280.
James F Booker Bonnie G. Colby 《Journal of the American Water Resources Association》1995,31(5):877-888
ABSTRACT: Economic benefit functions of water resource use are estimated for all major offstream and instream uses of Colorado River water. Specific benefit estimates are developed for numerous agricultural regions, for municipal uses, and for cooling water in thermal energy generation. Economic benefits of hydropower generation are given, as are those for recreation on Colorado River reservoirs and on one free-flowing reach. Marginal and total benefit estimates for Colorado River water use are provided. The estimates presented here represent a synthesis of previous work, providing in total a comprehensive set of economic demand functions for competing uses of Colorado River water. Non-use values (e.g., benefits of preserving endangered species) are not estimated. 相似文献