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221.
This study focuses on assessing the impact of sublethal doses of paraquat on the survival, the emergence, the life span and the parasitic behavior of Diaeretiella rapae M’Intosh (Hymenoptera: Braconidae). The impact of sublethal doses was measured at room temperature using different densities of the cabbage aphid Brevicoryne brassicae. The results reveal that the field dose of paraquat caused 100% mortality in D. rapae. The percentage emergence of D. rapae decreased from 80.5% in the control group to 71.5% when treated with the lowest concentration of paraquat. Similarly, the life span of parasitoids that emerged from the mummy treated with paraquat also decreased significantly. Oviposition capability and ovipositor thrusting frequency of D. rapae also treated with sublethal dose paraquat decreased significantly along with a shortened patch residence time in the foraging area.  相似文献   
222.
This paper is to investigate the behavior of residents towards electrical and electronic waste (e-waste) recycling in Beijing. For this purpose a large sample questionnaire survey was performed to explore the residents’ characteristics of recycling behavior and preference of e-waste recycling pattern. Besides, the willingness of residents to participate in e-waste recycling was also assessed in our study. For this a logistic regression model was developed to estimate and explain residents’ willingness in e-waste recycling. The model showed that Convenience of recycling facilities and service, Residential conditions, Recycling habit and Economic benefits are four determinants of Beijing residents’ willingness and behavior in e-waste recycling. And centralized recycling pattern by professional recovery spots would have a broad prospect if various kinds of channels can be provided to make the residents feel more convenient in e-waste recycling.  相似文献   
223.
我国相继颁发了一系列劳动安全的专门法律、法规,同时在其他的一些法律、法规中,对劳动安全也做出了相应的法律规定,初步形成了劳动安全法规体系。作为劳动行政部门的监察执法人员,既要精通专门的劳动安全法律、法规,也必须掌握相关的法律规定,以提高监察执法工作的力度和水平。  相似文献   
224.
Results of breeding bird censuses in 1979 and 1980 were used to compare the relationships of both species and guilds to forest habitats in the White Mountains of New Hampshire. Several age classes of 11 forest cover types were studied: northern hard-woods (Fagus-Betula-Acer), spruce (Picea), spruce-fir (Picea-Abies), birth (Betula), swamp hardwoods (Acer-Pinus-Tsuga), pine (Pinus strobus andP. resinosa), balsam fir (Abies), aspen (Populus tremuloides andP. grandidentata), northern red oak (Quercus), oak-pine (Quercus-Pinus), and hemlock (Tsuga). All types were even-aged; only northern hardwoods had an additional uneven-aged condition. Forest cover types were also pooled to consider generalized habitats: hardwoods, mixed forest, or softwoods. Results of ordinations based on censuses of 74 bird species indicate that foraging guilds are more related to general cover types than are nesting substrate guilds, but bird species reflect habitat differences to a greater degree than do either guild scheme. Also, considerable overlap occurs in bird species distribution between hardwoods and mixed forests; softwoods show little overlap with other types. Discriminant function and classification analyses revealed that bird species composition can be used to correctly classify general forest habitats more accurately (83.8%) than either foraging (63.2%) or nesting substrate guilds (58.4%). These results indicate that, of the habitats studied, avian species compositions are more characteristic than are foraging or nesting substrate guild composition, which tend to be similar across forest habitats.  相似文献   
225.
Flood area and damage estimation in Zhejiang,China   总被引:1,自引:0,他引:1  
A GIS-based method to estimate flood area and damage is presented in this paper, which is oriented to developing countries like China, where labor is readily available for GIS data collecting, and tools such as, HEC-GeoRAS might not be readily available. At present local authorities in developing countries are often not predisposed to pay for commercial GIS platforms. To calculate flood area, two cases, non-source flood and source flood, are distinguished and a seed-spread algorithm suitable for source-flooding is described. The flood damage estimation is calculated in raster format by overlaying the flood area range with thematic maps and relating this to other socioeconomic data. Several measures used to improve the geometric accuracy and computing efficiency are presented. The management issues related to the application of this method, including the cost-effectiveness of approximate method in practice and supplementing two technical lines (self-programming and adopting commercial GIS software) to each other, are also discussed. The applications show that this approach has practical significance to flood fighting and control in developing countries like China.  相似文献   
226.
通过对松花江河冰的物理力学性能试验和松花江公路大桥桥墩的流冰动压力测量、桥面的脉动测量 ,依据国内外对冰 -结构相互作用的分析 ,提出了适合我国黑龙江冰情特点的春季流冰冰荷载的计算方法。  相似文献   
227.
基于多Agent技术的交通事故救援系统的研究   总被引:6,自引:0,他引:6  
着重介绍了目前人工智能领域的研究热点问题———Agent技术的概念与原理 ,以及多Agent组的概念和分类 ;提出了基于多Agent技术的交通事故救援系统的流程框架 ;论述了该系统每一个Agent成员所能够完成的主要功能 ;通过该系统的实现 ,可以提高交通事故的及时报警与快速解决的效率 ,实行更加有效的交通流量合理分配 ;在利用既有交通基础设施的基础上增强了出行者的出行便利。笔者认为 ,随着Agent技术和网络技术研究的不断深入 ,基于Agent的应用研究必将有着更广泛的应用前景  相似文献   
228.
提高交通安全——实现智能汽车的研究   总被引:1,自引:1,他引:1  
主要介绍了通过智能汽车的研究 ,提高城市交通安全的必要性 ;综述了发达国家关于智能汽车研究的现状与趋势 ,并通过国外智能汽车发展的趋势 ;进一步论证智能汽车的研究是汽车工业发展的方向 ,也是提高交通安全的重要手段之一。此外 ,论文提出利用模式识别技术的智能汽车的结构框架 ;指出神经网络方法应用与模式识别技术结合的优势。最后 ,论文在阐述我国需要发展智能汽车的同时 ,提出应结合中国国情相应研究相关理论 ,为今后的实施奠定基础的近期目标 ,并提出展望  相似文献   
229.
230.
本文在剖析绿色技术的概念内涵与特征的基础上,构建了由清洁生产技术、资源化技术、末端治理技术、生态农业技术、绿色食品技术、清洁消费技术与生态恢复技术等为主要内容的我国绿色技术体系,并从行政、经济、法律、教育及科研等五个方面阐述了促进我国可持续发展的绿色技术实施策略。  相似文献   
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