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1.
No studies were reported on the field of coastal eutrophication research by using bibliometrics. The objective of this study was to evaluate the coastal eutrophication research performance based on all the related articles in Science Citation Index databases from 1993 to 2008. Document type, publication output, authorship, keywords, publication pattern, country, and institute of publication were analyzed. The USA contributed 35.0% of total articles where the ten major industrial countries accounted for the majority of the total production. An indicator citation per publication was presented in this study to evaluate the impact of number of authors, institutes, countries, and journals. The mean value of citation per publication of collaborative papers was higher than that of single country or institute publications. Collaboration trend was toward multi-authors, multi-institutes and multi-countries papers. This was coincident with the research trends of coastal eutrophication, which was thought to be a component of global change. Additionally, keywords analysis was used to indicate the formation and shift of hot research.  相似文献   

2.
This is an overview of Session 2c dealing with the regulatory, policy and economic issues related to carbon dioxide and its impact on global climate change. The information is taken from the two papers presented in this session (the U.S. Perspective by Dennis Leaf and the European Perspective by Hans J.H. Verolme) and from the panel discussion that took place at the end of the session. The overview focuses primarily on the policy responses of both the United States (US) and the United Kingdom (UK) to changes in global atmospheric pollution. To a lesser extent, the progress of policy responses to these changes is discussed. The United Nations Framework Convention on Climate Change (UNFCCC) has been signed and ratified by over 180 countries. The UNFCCC contained no binding targets or timetables for emissions reductions. The Kyoto Protocol [United Nations. Kyoto Protocol to the United Nations Framework Convention on Climate Change. UNEP.IUC/99/10. Chatlelaine, Switzerland: United Nations Environment Programme's Information Unit for Conventions, for the Climate Change Secretariat, 1997] to the UNFCCC did contain targets and timetables for reductions of greenhouse gases on the part of developed countries. The US has signed but not ratified the Kyoto Protocol. The US has experienced some movement to reduce greenhouse gas emissions on the part of various levels of government, as well as the private sector. The UK's commitment to reducing green house gases is laid down in the UK Climate Change Programme 2000. The UK is a member of the European Union (EU). In this context, an example of EU-wide progress, the voluntary agreement with car manufacturers to reduce CO(2) emissions in new vehicles, will be discussed. In addition, there will be some discussion on the UK CO(2) trading scheme that created the first market in the world in April 2001. Overall, the policy process is constantly informed by scientific research. In the case of climate change, much of this work is carried out under the auspices of international scientific panels.  相似文献   

3.
控制排水条件下土壤氮素的运移   总被引:2,自引:0,他引:2  
为研究暗管控制排水与非控制排水条件下, 不同排水出口控制高度对土壤中氮素分布和迁移的影响, 在湖北省荆州市四湖工程管理局丫角排灌试验站进行了野外试验。试验结果表明, 无论采取控制排水与否, 土壤垂直剖面上硝态氮浓度均有一致的变化规律: 20 cm处浓度最高, 在40~60 cm浓度急剧减小, 60~80 cm浓度值很小(1 mg/kg左右); 控制排水对土壤硝态氮的减小率有显著影响, 表现在控制水位越高, 土层间硝态氮减小率最大; 控制排水能降低表层土壤硝态氮的迁移; 铵态氮与硝态氮迥然不同, 无论采取控制排水与否, 铵态氮在土壤垂直剖面上的含量变化不大; 控制排水对铵态氮的含量也有一定的影响, 表现在控制排水位越低, 土壤中铵态氮的含量越小.  相似文献   

4.
近年来,由于人类生产生活的影响,以化肥农药使用为主的面源污染和以工业排放为主的点源污染日益加剧,全球尤其是海岸带氮含量逐渐升高,对滨海植被的生长产生了巨大的影响。在这个背景下,通过温室模拟实验研究不同供氮水平对互花米草的影响,对研究氮对入侵植物的影响作用机制有重大意义。互花米草在两种氮肥不同氮水平处理下,株高、叶面积、生物量等生长指标以及根冠比、根长/株高等指标的变化情况不同。结果表明:随着氮量增加,米草株高、叶面积、总生物量和地上部分生物量呈先上升后下降的趋势,地下部分生物量、根冠比和根长/株高比则呈下降趋势;各项指标在无机氮肥不同氮水平处理之间存在显著差异,但在有机氮肥的各处理间差异无显著性。这说明适当的供氮水平有利于互花米草的生长,而高氮则抑制其生长  相似文献   

5.
An overview of original information available from Russian language papers on radionuclide transfer to milk is provided. Most of the data presented have not been taken into account in international reviews. The transfer coefficient (F(m)) values for radioactive isotopes of strontium, caesium and iodine are in good agreement with those previously published. The Russian language data, often based on experiments with many animals, constitute a considerable increase to the available data for many less well-studied radionuclides. In some instances, the Russian language data suggest changes in recommended values (e.g. Zr and Ru). The information presented here substantially increases the amount of available data on radionuclide transfer to milk and will be included in the current revision of the IAEA TRS Handbook of parameter values for radionuclide transfer.  相似文献   

6.
三峡库区消落带农用坡地氮素流失特征及其环境效应   总被引:1,自引:0,他引:1  
三峡库区消落带坡地的自发农用较为常见,消落带的这种利用方式可能加剧养分流失并对库区水环境造成影响.通过对库区2011~2013年3个落干期消落带农用坡地的地表径流、壤中流中氮素形态与浓度进行定位监测,研究消落带农用坡地氮素流失特征及其环境效应.结果表明:常规施肥下,消落带农用坡地侵蚀模数为1 443 kg/(hm2·a),落干期内坡地平均径流量为230 mm,径流系数为0.58,其中壤中流流量占总径流量的77%.历次降雨产流事件中常规施肥处理时,地表径流、壤中流中TN平均浓度分别是4.85±0.85、20.73±2.05 mg/L,落干期地表径流(泥沙)和壤中流的TN流失量分别为6.63± 1.19、35.22±3.38 kg/hm2,分别占当季施肥量的2.2%、11.7%.可见,随壤中流流失是三峡库区消落带农用坡地氮素流失的主要途径.与常规施肥处理相比,减量施肥处理使地表径流(泥沙)、壤中流TN流失通量分别显著降低了25%、48%,表明减少氮肥用量可以显著降低消落带农用带来的环境风险,建议消落带农用地氮肥进行减量施肥,使其既不影响作物产量,也显著降低氮流失.  相似文献   

7.
以坡耕地柑桔园为研究对象,地表覆盖方式采用对照、秸秆覆盖和地膜覆盖3个处理,实验采用完全方案。结果表明,在本实验条件下,坡地地膜覆盖处理一定程度增加了径流量,而秸秆覆盖处理与对照每次降雨径流量基本相当;各处理土壤氮磷养分均有一定程度的流失,以氮素流失量较高,磷素流失量相对较低;在地膜覆盖条件下,柑桔园地表径流中N、P流失量较高,其总氮和总磷流失系数分别达0054%和0064%,而秸秆覆盖总氮和总磷流失系数最低;对不同地表覆盖方式柑桔园地表径流水体氮素形态特征分析表明,可溶性氮素占总氮的比例较高,可溶性氮素中又以NO-3 N为主,而NH+4 N所占的比重较低。以上结果说明,在丹江口库区,氮素污染风险要高于磷,防控的主要矛盾是氮,而秸秆覆盖是减少坡耕地养分流失较好的管理措施  相似文献   

8.
This study estimates efficient nitrogen load reductions to the Stockholm archipelago, a Swedish coastal zone in the Baltic Sea, and compares these with politically determined and implemented nitrogen abatement programs. The region is relatively well equipped with necessary data, and a simple programming model is constructed. The results show a large divergence in efficient nitrogen reductions, mainly due to the divergences in benefit estimates from water quality improvements in the archipelago. However, the results need to be interpreted with caution due to all uncertainties related to predicting net values from changes in nitrogen load to a coastal zone. In spite of this, it is still of policy relevance to infer results which show that the politically determined target coincides with an efficient nitrogen reduction at relatively low benefit estimate, but that actual net benefits could be increased from a reallocation of abatement measures towards more low cost measures.  相似文献   

9.
中国环境教育研究的历史与未来趋势分析   总被引:1,自引:0,他引:1  
通过对1979年以来中国环境教育学术文章在数量、内容和研究方法等方面的分析。发现中国环境教育研究自1994年开始持续升温。2000年开始从文章内容和研究方法上明显显示出转向可持续发展教育方向的趋势,2004年开始从文章数量上也显示出转向可持续发展教育的方向o20多年来的环境教育研究中。对环境教育意义的阐述和国外环境教育动态的研究分量最重,研究方法的探讨和研究则表现出对主流教育领域的影响敏感且响应及时。但这些文章显示出的环境教育研究方法绝大多数以思辨为主。实证研究、质的研究缺乏。对文章作者分析结果显示。中国环境教育研究队伍很不稳定。缺乏基本的研究经费支持是研究队伍不能保持稳定并缺乏在本土开展的实证和质的研究的根本制约因素。怎样协调因资源禀赋和发展程度不同而导致各国在开展环境教育时出现环境价值观和环境立场产生差异甚至对立的现象。是未来环境教育研究不可回避的任务。  相似文献   

10.
The development and purpose of the FREDERICA radiation effects database   总被引:3,自引:2,他引:1  
Any system for assessing the impact of a contaminant on the environment requires an analysis of the possible effects on the organisms and ecosystems concerned. To facilitate this, the FREDERICA radiation effects database has been developed to provide an online search of the known effects of ionising radiation on non-human species, taken from papers in the scientific peer reviewed literature. The FREDERICA radiation effects database has been produced by merging the work done on radiation effects under two European funded projects (FASSET and EPIC) and making the database available online. This paper highlights applications for the database, gaps in the available data and explains the use of quality scores to help users of the database determine which papers may benefit their research in terms of techniques and reproducibility.  相似文献   

11.
本文介绍了良性发展的基本概念及内涵 ,同时也介绍了提出良性发展的思想过程 ,并对良性发展与可持续发展的关系作了初步的讨论。  相似文献   

12.
This article summarises the abatement of NO(x) pollution by using sorbing catalytic materials with special relevance to the challenge presented in fixed installations sources. A general vision of the origins of the different pollutants, with emphasis on nitrogen oxides formation, is presented as introduction. The impact of NO(x) pollution comprises additionally a quick view of its toxicity and environmental effects. Actual solutions are presented especially the case of the selective catalytic reduction (SCR) process with its advantages and difficulties. The new concepts for NO(x) abatement are also analysed. In such a way, updated information on solid sorbents for NO(x) removal is provided by including metal oxides, spinelles, perovskites, double-layered cuprates, zeolites, carbonaceous materials, heteropolyacids (HPAs), and supported heteropolyacids. The possibility of reducing those sorbed NO(x) is also underlined. Sorption mechanisms are analysed and clarified by emphasising convergence and disagreement points.  相似文献   

13.
Assessment of climate change vulnerability of tourism in Hungary   总被引:1,自引:0,他引:1  
This paper applies vulnerability assessment methodology to assess the comparative vulnerability of different tourism supply types by region in Hungary. The steps of the methodology include (1) definition of tourism supply typology, (2) identifying exposure indicators, (3) identifying sensitivity indicators, (4) identification of adaptive capacity indicators and (5) developing a vulnerability map. It is clear that climate change has potential negative effects on tourism in Hungary, but the spatial distribution, as well as the sub-sectoral (by tourism supply types) differences of these impacts is almost unknown. Most research papers dealing with the vulnerability of tourism mainly focus on a specific tourism type, whereas this article aims to address all of them from a regional point of view. The key results presented in this paper include the vulnerability map of the country showing the relative vulnerability of different tourism supply types and detailed analysis investigating the possible causes and driving factors. We have categorized tourism regions based on the five most vulnerable tourism supply types. The most significant of them all turned out to be outdoor event-based tourism, being the most vulnerable in the two southern regions, since the expected impacts of climate change are foreseen to be the most significant in these areas.  相似文献   

14.
Sustainability is an important concept for society, economics, and the environment, with thousands of research papers published on the subject annually. As sustainability science becomes a distinctive research field, it is important to define sustainability clearly and grasp the entire structure, current status, and future directions of sustainability science. This paper provides an academic landscape of sustainability science by analyzing the citation network of papers published in academic journals. A topological clustering method is used to detect the sub-domains of sustainability science. Results show the existence of 15 main research clusters: Agriculture, Fisheries, Ecological Economics, Forestry (agroforestry), Forestry (tropical rain forest), Business, Tourism, Water, Forestry (biodiversity), Urban Planning, Rural Sociology, Energy, Health, Soil, and Wildlife. Agriculture, Fisheries, Ecological Economics, and Forestry (agroforestry) clusters are predominant among these. The Energy cluster is currently developing, as indicated by the age of papers in the cluster, although it has a relatively small number of papers. These results are compared with those obtained by natural language processing. Education, Biotechnology, Medical, Livestock, Climate Change, Welfare, and Livelihood clusters are uniquely extracted by natural language processing, because they are common topics across clusters in the citation network.  相似文献   

15.
乌江中上游水库-河流体系夏秋季N、Si分布特征   总被引:1,自引:0,他引:1  
测定了乌江中上游的洪家渡至乌江渡水库段水体中总氮、氨氮和溶解态硅等营养物质含量,并现场测定水深、温度、溶解氧和叶绿素浓度等理化参数。研究结果表明:在夏秋水库分层现象不断减弱期间,氮、硅的空间分布受水库生物地球化学作用差异的影响,在空间上具有明显不同的分布特征。流域内地表水总氮含量变化不大,水库内垂直分布也较均一;7至9月份河流和水库表层水体总氮含量平均值呈下降趋势,分别为347、317和 3.00 mg/L。7、8月份水库表层水溶解态硅含量明显低于上下游水体,说明水库生物吸收作用强而导致水库滞留溶解态硅;在垂直剖面上,0~30 m 水体溶解态硅含量随水深增加而增加,30~60 m 溶解态硅含量变化不大,这反映了水库上层水体生物对硅的吸收,和下层水体溶解态硅的吸收和释放平衡。  相似文献   

16.
知识网络是由创造、转移、吸收和应用知识的行为主体在知识的传播与交流过程中彼此联结而形成的网络结构。以国际ISI和国内VIP数据库中2000~2009年发表于生物技术领域的合著论文作者信息统计数据为数据源,基于社会网络分析的理论和方法,从国际和国内省级层面运用UCINET和Pajek软件分析知识网络的空间极化和扩散规律。总体上看网络仍处于量的扩张期,网络的稳健性正在逐步提高,网络结构开始向成熟型转变。国际层面上看,知识网络的空间极化现象明显。国内层面上看,知识网络由等级结构向扁平结构转变,空间上相应地经历了由一极向多核再向多中心发展的过程。依据知识网络空间分布特征,将知识交流区域分为知识集聚区、知识门户区、知识途径区及知识边缘区四大类型,并对我国的技术创新政策提出对策建议  相似文献   

17.
Radon gas was allowed to accumulate in its radium source and then injected into a 36 m(3) test room, resulting in an initial radon concentration of 15 kBq m(-3). Filter papers were used to collect the short-lived radon progeny and thus to measure the Potential Alpha Energy Concentration (PAEC) in-situ in the year 1984 at different times and conditions according to the experimental design. The radon progeny collected on the filter papers were studied as a function of aerosol particle concentration ranging from 10(2)-10(5) particles cm(-3) in three different experiments. The highest aerosol particle concentration was generated by indoor cigarette smoking. Those filters were stored after the experiment, and were used after 16 years to study the activity of the radon long-lived alpha emitter progeny, (210)Po (T(1/2)=138 days). This isotope is separated from the short-lived progeny by (210)Pb beta emitter with 22.3 years half-life. After 16 years' storage of these filters, each filter paper was sandwiched and wrapped between two CR-39 nuclear track detectors, to put the detectors in contact with the surfaces of different filters, for 337 days. Correlation between the PAEC measured using filter papers in the year 1984 and the activity of long-lived alpha emitter (210)Po on the same filter papers measured in the year 2000 were studied. The results of the (210)Po activity showed a very good correlation of 0.92 with the PAEC 16 years ago. The results also depict that the PAEC and (210)Po activity in indoor air increased with the increase of aerosol particle concentration, which shows the attachment of short-lived radon progeny with the aerosol particles. The experiment proves that indoor cigarette smoking is a major source of aerosol particles carrying radon progeny and, thus, indoor cigarette smoking is an additional source of internal radiation hazard to the occupants whether smoker or non-smoker.  相似文献   

18.
This article is a review of work published in various journals and conference proceedings on the topics of Simulation Modelling for Sustainability between January 2000 and May 2015. A total of 192 papers are reviewed. The article intends to serve three goals. First, it will be useful to researchers who wish to know what kinds of questions have been raised and how they have been addressed in the areas of simulation modelling for sustainability. Second, the article will be a useful resource for searching research topics. Third, it will serve as a comprehensive bibliography of the papers published during the period. The literature is analysed for application areas, simulation methods and dimensions of the triple bottom line model of sustainable development.  相似文献   

19.
The Instituto de Radioprote??o e Dosimetria has been coordinating the National Intercomparison Program (PNI) for 15 years, from 1991 to 2005. The objective is to evaluate the analytical performance of the laboratories in low-level activity concentration radionuclide assays in environmental samples. This work presents an evaluation of PNI data from 42 intercomparison runs, which distributed to 22 Brazilian laboratories 2511 samples evaluating 5768 radionuclide assays involving 32 radionuclides in the period from 1991 to 2004. The laboratory performance was evaluated using the Normalized Standard Deviation used by the U.S. EPA. For comparison aims, the Normalized Deviation, used by BIPM was also applied. Laboratory performance were grouped and evaluated in three periods of 5 years each. The first period shows, an average value of good performance of 71.2%, the second shows an average of 78.6% and the last an average of 82.3%. Performance for each kind of radionuclide is also presented.  相似文献   

20.
丹江口库区典型小流域水体氮素分布特征研究   总被引:1,自引:0,他引:1  
丹江口水库水质总体良好,但总氮浓度超标问题突出。为明确不同类型小流域氮素的分布和输出特征,优化制定库区控氮措施,选择库周典型小流域,开展水体氮素浓度系统观测和分析。结果显示:(1)余家湾(养殖型)总氮浓度平均为21.23 mg/L,五龙池(村落型)总氮浓度平均为4.00 mg/L,高于钱家沟(自然型)和张沟(农田型);五龙池(村落型)硝态氮浓度最高,平均为2.37 mg/L,张沟最低,平均为1.06 mg/L;余家湾(养殖型)氨氮浓度远高于钱家沟(自然型)、五龙池(村落型)和张沟(农田型)。(2)钱家沟(自然型)氨氮浓度沿程下降趋势显著(p0.05);张沟(农田型)硝态氮(p0.01)和总氮浓度(p0.01)沿程上升趋势显著,坑塘湿地等微地形结构可能是影响小流域氮素的沿程变化的主要因素。(3)钱家沟(自然型)和五龙池(村落型)氮素冬季(12~2月)浓度较高,夏秋季(6~11月)浓度较低,春季(3~5月)波动最大;张沟(农田型)氮素高值出现在6月;余家湾(养殖型)氮素浓度高值出现在8月。(4)余家湾(养殖型)氮素以氨氮为主,五龙池(村落型)、张沟(农田型)和钱家沟(自然型)以硝态氮为主。基于上述结论,后续丹江口库区氮素控制应系统梳理不同类型小流域的分布和数量,重点关注养殖型小流域的氨氮污染和村落型小流域的硝态氮污染。  相似文献   

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