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61.
Robert J. Langridge Bryan D. MacGregor 《Journal of Environmental Planning and Management》1986,29(1):19-22
This study analyses the behaviour of high technology and new firms in the Newbury District of Berkshire in terms of employment, location, genealogy, and local economic impact. It finds that encouraged by good communications networks and a ‘resident electronics establishment’, the direct, as opposed to the indirect, employment consequences are generally encouraging, but not widely replicable. Moreover, the general picture of employment growth masks important differences in labour demand across occupations, particularly with respect to ‘traditional male’ skilled manual workers. 相似文献
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63.
Dynamics of Bacterial Abundance,Biomass, Activity,and Community Composition in the Oligotrophic Traunsee and the Traun River (Austria) 总被引:1,自引:0,他引:1
Klammer Susanne Posch Thomas Sonntag Bettina Griebler Christian Mindl Birgit Psenner Roland 《Water, Air, & Soil Pollution: Focus》2002,2(4):137-163
The holomictic Traunsee is the deepest and second largest lakein Austria. The special characteristic of this ecosystem isthe fact that local salt and soda industries presumably alterthe lake by the discharge of waste materials. Since thebeginning of the 20th century salt and soda works areannually releasing up to 50,000 tons of solid wastes and up to150,000 tons of chloride into Traunsee. To assess potentialeffects of these anthropogenic impacts on the bacterioplanktonthree sampling sites, influenced as well as not influenced bythe industrial discharge, were chosen for comparison andsampled monthly from November 1997 to October 1998. Bacterialabundance ranged between 0.4 to 3.0 × 106 cells ml-1 with decreasing numbers along the depth profile. Theproportion of actively respiring bacteria, i.e. INT [2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride]reducing cells, never exceeded 10% of DAPI (4',6'-diamidino-2-phenylindole) stained cells. Fluorescence in situ hybridization (FISH) was used to examine the seasonal and spatial distribution of dominant phylogenetic groups of thebacterioplankton. Up to 84% of bacteria detected with DAPIcould be detected via FISH applying the universal bacterialprobe EUB338. Percentages of alpha- and beta-Proteobacteriaand members of the Cytophaga-Flavobacterium cluster did notexceed 60% of DAPI-stained cells.Beta-Proteobacteriaappeared to be the most abundant group, not only in Traunsee butalso in two reference lakes, Attersee and Hallstättersee. No significant differences in any of the bacterial parameters couldbe detected between the three sampling sites and all measurementswere found in the range reported for oligotrophic lakes. The highdischarge of the Traun River, resulting in a lake water renewaltime of only one year, may diminish possible effects of industrial waste discharge in the pelagic zone. 相似文献
64.
运用川北广元历年飞播成效调查以及固定标准地观测的结果,结合笔者从事飞播造林技术与管理工作的经验,得出:飞播造林是速度快、省劳力、投资少、成本低、效益高的造林方式,推广飞机播种造林是绿化川北山地,迅速治理流域生态环境和实现山区经济可持续发展的有效措施 相似文献
65.
流动危险源毒气泄漏事故伤害模型研究 总被引:2,自引:0,他引:2
笔者介绍了危险货物道路运输的现状和特点,阐述了进行流动危险源事故后果分析的必要性,提出了流动危险源运动时毒气泄漏事故伤害模型,并利用该模型进行了数值模拟,证明该模型分析流动危险源运动时毒气泄漏事故的后果是可行的。 相似文献
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67.
Size-Dependent Selective Leaf Damage by Insects and Some Methodological Implications of This Phenomenon 总被引:1,自引:0,他引:1
The area of leaves on birch (Betula pubescens ssp. tortuosa) auxiblasts and brachyblasts and the degree of their damage by the complex of leaf-gnawing and leaf-mining insects were studied in a light birch forest. The results showed that phyllophagous insects, primarily snout beetles, prefer young leaves on the apexes of auxiblasts. Thus, selective damage is inflicted on smaller leaves, both on the auxiblasts and in the entire sample. This phenomenon is widespread and may manifest itself in different ways, depending on the pattern of leaf area distribution along the extended shoot and the feeding preferences of the insects. Thus, it is necessary to reconsider research methods and approaches based on the assumption that insects damage leaves nonselectively, irrespective of their size. 相似文献
68.
对催化装置四机组运行状态进行分析,介绍了齿轮箱高速轴及轴瓦损坏的情况,并分析说明了引起损坏的原因。结合生产实际确定合理的齿轮轴修复工艺方案,即采用激光融敷表面修复高新技术,迅速可靠地对齿轮轴进行修复,保证了设备运行的可靠性,从而实现安全生产、节能降耗、效益增长。 相似文献
69.
70.
Myron MoInau Walter J. Rawls David L. Curtis C. C. Warnick 《Journal of the American Water Resources Association》1980,16(3):428-432
ABSTRACT: Data from a network of 45 shielded precipitation gages on the Reynolds Creek Experimental Watershed in Southwestern Idaho were analyzed to determine the optimum gage density for estimating mean annual precipitation. Four subsets of the 45 gage network were used to derive a curve of mean annual precipitation versus number of gages with a confidence band at the 95 percent level. When less than 20 gages were used in the estimate, the confidence interval widens rapidly. Estimates were improved by stratifying gages on the basis of plant cover class or by elevation bands. Sixty-four percent of the variation in mean annual precipitation was accounted for by elevation and cover class. The aspect and hydrologic soil classification were not statistically significant. 相似文献