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131.
Pan G Zhang MM Chen H Zou H Yan H 《Environmental pollution (Barking, Essex : 1987)》2006,141(2):195-200
Algal removal abilities of 26 clays/minerals were classified into three categories according to the 8-h equilibrium removal efficiency (Q8h) and removal rate at a clay loading of 0.7 g/L. Type I clays (sepiolite, talc, ferric oxide, and kaolinite) had a Q8h > 90%, a t50 (time needed to remove 50% of the algae) < 15 min, and a t80 < 2.5 h. Type II clays (6 clays) had a Q8h 50-90%, a t50 < 2.5 h, and a t80 > 2.5 h. Type III clays (14 clays) with Q8h < 50%, t50 > 8 h and t80 > 14 h had no practical value in removal of algal blooms. When the clay loading was reduced to 0.2 g/L, Q8h for all the 25 materials decreased to below 60%, except for sepiolite whose Q8h remained about 97%. The high efficiency for sepiolite to flocculate M. aeruginosa cells in freshwaters was due to the mechanism of netting and bridging effect. 相似文献
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Gyamfi Bright Akwasi Sarpong Steve Yaw Bein Murad A. 《Environmental science and pollution research international》2021,28(9):11016-11029
Environmental Science and Pollution Research - The debate on ecological matters that relate to the biomass emissions nexus has gained prominence and different scholars have suggested various forms... 相似文献
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电梯维护保养质量评价是一项评价指标多,指标间关系复杂,评判结论模糊的工作。应用灰色综合评价法对解决以上工作中的难点有很好的效果。本文介绍了灰色综合评价法的基本思想和原理,给出了灰色评价法指标体系的构造方法、计算过程以及关联系数计算公式的分辨系数选取原则。通过实例分析,得出电梯维护保养质量评价中应用灰色综合评价法的特点和要注意的事项。 相似文献
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Large-Scale Conversion of Forest to Agriculture in the Boreal Plains of Saskatchewan 总被引:1,自引:0,他引:1
Keith A. Hobson †‡ Erin M. Bayne † Steve L. Van Wilgenburg 《Conservation biology》2002,16(6):1530-1541
139.
Michael A Patten Eyal Shochat Dan L Reinking Donald H Wolfe Steve K Sherrod 《Ecological applications》2006,16(2):687-695
Bird populations in North America's grasslands have declined sharply in recent decades. These declines are traceable, in large part, to habitat loss, but management of tallgrass prairie also has an impact. An indirect source of decline potentially associated with management is brood parasitism by the Brown-headed Cowbird (Molothrus ater), which has had substantial negative impacts on many passerine hosts. Using a novel application of regression trees, we analyzed an extensive five-year set of nest data to test how management of tallgrass prairie affected rates of brood parasitism. We examined seven landscape features that may have been associated with parasitism: presence of edge, burning, or grazing, and distance of the nest from woody vegetation, water, roads, or fences. All five grassland passerines that we included in the analyses exhibited evidence of an edge effect: the Grasshopper Sparrow (Ammodramus savannarum), Henslow's Sparrow (A. henslowii), Dickcissel (Spiza americana), Red-winged Blackbird (Agelaius phoeniceus), and Eastern Meadowlark (Sturnella magna). The edge was represented by narrow strips of woody vegetation occurring along roadsides cut through tallgrass prairie. The sparrows avoided nesting along these woody edges, whereas the other three species experienced significantly higher (1.9-5.3x) rates of parasitism along edges than in prairie. The edge effect could be related directly to increase in parasitism rate with decreased distance from woody vegetation. After accounting for edge effect in these three species, we found evidence for significantly higher (2.5-10.5x) rates of parasitism in grazed plots, particularly those burned in spring to increase forage, than in undisturbed prairie. Regression tree analysis proved to be an important tool for hierarchically parsing various landscape features that affect parasitism rates. We conclude that, on the Great Plains, rates of brood parasitism are strongly associated with relatively recent road cuts, in that edge effects manifest themselves through the presence of trees, a novel habitat component in much of the tallgrass prairie. Grazing is also a key associate of increased parasitism. Areas managed with prescribed fire, used frequently to increase forage for grazing cattle, may experience higher rates of brood parasitism. Regardless, removing trees and shrubs along roadsides and refraining from planting them along new roads may benefit grassland birds. 相似文献
140.
Gillian M. Raab Duncan P. H. Laxen Niall Anderson Steve Davis Michael Heaps Mary Fulton 《Environmental geochemistry and health》1993,15(4):191-200
The water lead concentrations measured in the homes of children who were part of the Edinburgh Lead study are related to the characteristics of the water supply and the household plumbing. At the time of the study one of the City of Edinburgh's two water supplies was lime treated to reduce plumbosolvency but in the second supply this treatment had not yet become effective. This allows us to estimate the extent to which this type of water treatment reduces water lead concentrations, in houses with lead plumbing, to comply with existing and proposed limits for lead in water. The kitchen cold water was supplied from a lead storage tank in 69 (15%) of the houses. These houses had the highest lead concentrations and water treTo whom correrspondence should be addressed. 相似文献