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81.
环球空气微生物考察   总被引:12,自引:0,他引:12       下载免费PDF全文
在1986年10月31日~1987年5月17日间,中国"极地"船作环球暨南极的航行中对空气微生物进行了考察。测点分布在其行经的30921海里的空气中,样品计432份。作了对微生物的含量分析及分类研究。结合有关参数,比较各类型环境间微生物含量的差别,指出本环球航行所经各区空气微生物的状况。结果表明,西半球、大西洋、温带、台湾海峡、南美洲、中国、坎帕纳(阿根廷)、黄海等区域的空气微生物含量一般分别比同类环境的高。南大洋空气较洁净,所考察的环球空气至少有15属细菌和5属酵母,葡萄球菌、微球菌较多,长城站空气中有芽孢杆菌。的结果说明长城站的空气微生物含量高于其他两测区的,内海(此处指麦克斯威尔湾)空气的微生物含量高于开阔性海域的(指南设得兰群岛海域),与其他区域比,陈皓文等,国际五城市空气微生物概况(待发表)。陈皓文等,中国南极长城站微生物考察(待发表)。南设得兰群岛区域的微生物(待发表)。表7世界5个海峡空气微生物含量表8南美一些近海河流、水道空气微生物含量表9中国海空气微生物含量(CFL/m3)南极半岛空气仍较洁净,但长城站的空气有待改善。当船只进入中国海域时,均测定了空气微生物。结果列于表9,表中说明黄海的空  相似文献   
82.
Abstract

Objective: Recent news reports in 2016 indicated that across Miami–Dade County, Florida, driving under the influence (DUI) arrests have decreased substantially. The objective of this research was to determine the reasons for the decline in DUI arrests from 2009 to 2016. Are there fewer impaired drivers on the roads? Can DUI enforcement and prosecution be improved?

Methods: The following methods were used in this study: (1) Analysis of existing DUI arrest and crash data; (2) conducting and analysis of a telephone survey of reported knowledge, attitudes, and behaviors concerning impaired driving; (3) conducting and analysis of roadside surveys on the roads on weekend nights in Miami–Dade County; (4) information from focus group discussions with police and prosecutors in Miami–Dade County; and (5) a comprehensive review of the best DUI prevention practices and enforcement strategies used across the country.

Results: DUI arrests decreased 64% in Miami–Dade County between 2009 and 2016. This was a significantly larger decrease than has occurred in the State of Florida as a whole (34%) and in the United States (29%) over the same time period. The decline was not due to any decline in DUI behavior in the county.

Conclusions: Based upon the data and information gathered in this project, the following actions were recommended for Miami–Dade County: (1) County police chiefs need to find ways to overcome law enforcement apathy toward DUI enforcement and persuade their traffic enforcement officers to be proactive rather than reactive when it comes to identifying and making impaired driving stops. (2) County police agencies should join forces to conduct more sobriety checkpoints. Checkpoints are safer for both the police and the drivers going through them and serve as a general deterrent to impaired driving. (3) An interagency DUI task force or team of 5 to 7 officers should be established within the county. These officers would be solely dedicated to DUI enforcement and paid for by each individual agency or under a grant from the state or federal government.  相似文献   
83.
官厅水库浮游植物功能群季节演替及其驱动因子   总被引:3,自引:0,他引:3  
官厅水库是北京市重要的水源地,其生态环境问题一直深受社会关注。以浮游植物功能群调查为基础,于2010年春夏秋三季对官厅水库进行生态调查,根据水库水环境特征,在永1000、妫1018+1、河口3个不同生境区域设置采样点,进行浮游植物水样采集。共鉴定出浮游植物112种(包括变种),分属于6门52属。浮游植物种类组成:绿藻门23属49种,占种类总数的43.75%;硅藻门12属34种,占30.36%;蓝藻门10属19种,占16.96%;裸藻门4属7种,占6.25%;甲藻门2属2种,占1.79%;隐藻门1属1种,占0.89%。浮游植物丰度秋季(8 889.97×10~4个/L)夏季(7 157.39×10~4个/L)春季(868.97×10~4个/L),三季均值为5 638.78×10~4个/L。3个季节里浮游植物划分为18个功能群,代表性功能群的季节演替为春季(F/MP/H1/C/D/G/W1)→夏季(Tc/M/Wo/C/N/X3/LM)→秋季(Tc/H1/C/D/W1/P)。利用典范对应分析方法,对同步取得的p、TN、TP、WT等环境因子与浮游植物功能群分之间的相关性进行分析。结果显示,WT、p、TP、NH_4-N是官厅水库浮游植物功能群演替的主要驱动因子。  相似文献   
84.
采用H2O2浸渍的修饰方法对ACF进行化学改性,并利用氮吸附等温线和XPS(X-ray photoelectron spectroscopy)的方法对ACF样品进行表征。通过在反应床上开展吸附实验,由此测定改性前后ACF脱除VOC(甲苯作为VOC的代表物)的效果,同时考察氧气、温度、水蒸气等因素对ACF脱除甲苯的影响。研究发现,改性使得ACF样品比表面积和孔容略有降低,但表面含氧官能团含量增加,吸附甲苯的能力也因此增强。当模拟烟气中O2浓度为5%时,ACF脱除VOC效果达到最佳,超过5%之后,氧的促进效果不再明显;温度40℃为最佳吸附温度;当烟气中加入水蒸气时,ACF对VOC的脱除效率降低。  相似文献   
85.
Na2S·HNO3改性活性炭对水中低浓度Pb2+吸附性能的研究   总被引:2,自引:0,他引:2  
采用回流蒸煮、微波焙烧的方法改性活性炭,通过Boehm滴定法、TG和FT-IR分析了改性前后活性炭表面官能团的变化情况.Boehm滴定表明:改性活性炭的总酸度、羧基、内酯基皆有增加;TG曲线中的多个失重峰说明了改性活性炭表面含氧基团的增加;FT-IR谱图上500~720 cm-1范围内新峰的出现说明了改性活性炭表面增加...  相似文献   
86.
Abstract:  Reintroduction of fire and grazing, alone or in combination, has increasingly been recognized as central to the restoration of North American mixed-grass and tallgrass prairies. Although ecological studies of these systems are abundant, they have generally been observational, or if experimental, have focused on plant species diversity. Species diversity measures alone are not sufficient to inform management, which often has goals associated with life-form groups and individual species. We examined the effects of prescribed fire, light cattle grazing, and a combination of fire and grazing on three vegetation components: species diversity, groups of species categorized by life-form, and individual species. We evaluated how successful these three treatments were in achieving specific management goals for prairies in the Iowa Loess Hills (U.S.A.). The grazing treatment promoted the greatest overall species richness, whereas grazing and burning and grazing treatments resulted in the lowest cover by woody species. Burning alone best achieved the management goals of increasing the cover and diversity of native species and reducing exotic forb and (predominantly exotic) cool-season grass cover. Species-specific responses to treatments appeared idiosyncratic (i.e., within each treatment there existed a set of species attaining their highest frequency) and nearly half of uncommon species were present in only one treatment. Because all management goals were not achieved by any one treatment, we conclude that management in this region may need refining. We suggest that a mosaic of burning and grazing (alone and in combination) may provide the greatest landscape-level species richness; however, this strategy would also likely promote the persistence of exotic species. Our results support the need to consider multiple measures, including species-specific responses, when planning and evaluating management .  相似文献   
87.
Piran P 《Disasters》2004,28(3):283-293
Afghan refugees in Iran, like many Muslims around the world, think that using contraceptives is against their religious beliefs. The majority of Iranians also thought so until a decade ago. Since then an all-encompassing social movement has emerged in Iran in which women and young people have played decisive roles. This movement has led to an attitude shift towards acceptance of family planning across Iranian society. High-ranking clerics, responding to the social movement, issued progressive edicts indicating that poor families could practise family planning. This paper reports the findings of focus group studies carried out among Afghan refugee men in two communities in Iran. The findings indicate that exposure to Iranian life, especially the rulings of Iranian clerics, have influenced Afghans' views on family planning. The findings also indicate that a system of justification is needed to help people avoid both social sanctions and individual stresses resulting from a controversial practice regarded as a sin for centuries.  相似文献   
88.
人工湿地基质中酶活性和细菌生理群的时空动态特征   总被引:30,自引:6,他引:24  
对复合垂直流人工湿地基质中6种酶酶活性和5种细菌生理类群数量进行了测定.结果表明各种酶酶活性在不同月份存在显著差异(p<0.05):纤维素酶、蛋白酶和磷酸酶在6月、9月和12月时都表现出较高的酶活性,并且都显著地高于3月的酶活性;β-葡萄糖苷酶在6月时酶活性显著地高于其它月;而脲酶活性在9月和12月时极显著地高于3月和6月(p<0.01);脱氢酶酶活性在6月和12月时明显高于3月和9月.相比较而言,6种酶酶活性的空间特征较为一致,下行流池酶活性显著高于上行流池活性(p<0.05),并且随着基质层深度的增加,酶活性亦相对递减.细菌生理类群数量在6月和9月达到高峰,并且所反映出来的空间规律与酶活性有一致性.  相似文献   
89.
季铵化改性稻草吸附去除水中SO42-的特性研究   总被引:1,自引:1,他引:0  
曹威  党志 《环境科学学报》2013,33(9):2466-2472
采用NaOH、环氧氯丙烷和三甲胺改性稻草秸秆,制备出含季铵基的吸附剂,用以去除水中的硫酸根离子(SO2-4).通过SEM、元素分析、13C-NMR表征发现,稻草改性后表面纤维结构暴露,含氮量增加,引入了大量的季铵基,吸附潜力显著提高.吸附实验结果表明,改性稻草吸附去除SO42-平衡时间约20min,pH为3~8范围内吸附效果较好.采用Langmuir吸附模型可较好地描述改性稻草对SO2-4的吸附等温线,其最大单分子层吸附量Qmax为74.76mg·g-1,吸附能力远大于原稻草(11.68mg·g-1).  相似文献   
90.
浮游植物分类是揭示浮游植物群落演替规律和开展水生态调查工作的基础.为了比较FG、MFG和MBFG功能群分类方法之间的差异,运用功能群分类和冗余分析(RDA)等方法,于2017年4月(平水期)和2017年8月(丰水期)对浮游植物群落结构和水环境理化指标进行采样分析,结果表明:①MFG功能群与FG功能群具有重叠部分,而MBFG功能群与FG和MFG相比差异较大.②FG功能群考虑了浮游植物的生理、生态学等特征,能更好地解释与环境的相关性,并且更准确反映环境因子与浮游植物生态位之间的关系.同时可以根据浮游植物优势功能群预测水库环境因子及富营养化状态,但是FG功能群需要具备系统的浮游植物鉴定知识,工作量大. MFG功能群分类方法简单易懂,能够较好的解释浮游植物与环境因子的关系,但功能群与环境因子联系较弱. MBFG功能群分类方法最为简单、高效,但是MBFG功能群对环境的解释度不够,分类依据过于简单,分组太少.③3个分类方法各有优缺点,根据研究目的不同以及实际需要选择合适的分类方法.  相似文献   
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