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81.
The first part of this paper presents an overview of national forest carbon balance studies that have been carried out in Europe. Based on these national assessments, an estimate is made of the present role of European forests in the global carbon cycle. Differences in the methodologies applied are discussed. At present, 15 European countries have assessed a national forest and/or forest sector carbon balance. Together, these studies cover 104 million ha and present the average situation in the mid-1980s. Most of the studies have used a static methodology to convert forest inventory data into carbon. Extrapolating those studies to the total forest area of Europe (149 million ha) (excluding the FSU), yields a whole tree carbon sink of 101.3 Tg C y−1 (9.5% of the European emissions) and a whole tree carbon stock of 7929 Tg C. Although in general the applied methodologies are comparable, they differ considerably in the way net fluxes are assessed and in the applied conversion coefficients. The role of forest fires in the European forest C balance might be larger than generally expected. A disadvantage of the static methodologies used is that they often regard only the forest ecosystem part of the carbon cycle which may result in misleading results concerning the role of the total forest sector; another disadvantage is that results are only valid for the year(s) on which the data are based. The second part of the paper discusses a methodology that could be applied to all national forests and forest sectors yielding more consistent results. The possibilities of using a large-scale forestry scenario model for a study on the present and future European forest sector carbon balance are presented. 相似文献
82.
边缘计算(edge computing, EC)是在靠近人、物或数据源头的网络边缘侧,融合网络、计算、存储、应用核心能力的新网络架构和开放平台.边缘计算将传统的集中式云计算处理的方式,改为将计算存储能力下移至网络边缘,面向用户和终端的方式,就近提供边缘智能服务.边缘计算极大地降低了由于数据回传造成的核心网和传输网的拥塞与负担,实现较低时延,带来较高带宽,同时能够快速响应用户请求并提升服务质量.当前,边缘计算已经成为未来第五代通信(5G)时代的重要使能技术,并写入第三代合作伙伴计划(3rd generation partnership project, 3GPP)标准.越来越多的运营商、设备商、芯片厂商加入建设边缘计算生态的行列,如何打造一个统一的标准化的边缘计算平台对于未来边缘生态的建设至关重要.因此,重点介绍当前边缘计算标准化的进展情况,从欧洲电信标准化协会(European Telecommunications Standards Institute, ETSI)最先提出边缘计算架构开始,到3GPP将边缘计算纳入未来5G发展的关键技术,再到中国通信标准化协会(China Communications Standards Association, CCSA)中边缘计算的立项与课题研究.每一部分的介绍均安排了大量对标准内容的分析和解释.最后介绍了近年来中国联通在边缘计算方面的研究成果.包括重要的边缘计算试点、联通未来边缘计算试点计划以及边缘计算的组网部署方案探索等内容.期望与产业界共同探讨边缘计算商业合作模式,共建网络边缘生态,全面推动5G业务的蓬勃发展. 相似文献
83.
为探究盐浓度对欧洲鳗肌原纤维蛋白热诱导凝胶形成性能的影响,测定了蛋白的浊度、表面疏水性和活性巯基的变化,考察了0.1、0.3、0.5 mol/L的NaCl浓度下的肌原纤维蛋白热诱导凝胶的性质。结果表明,欧洲鳗肌原纤维蛋白的浊度、表面疏水性和活性巯基分别在30、35和40 ℃开始增加。随着NaCl浓度的增加,肌原纤维蛋白的热吸收峰温度降低,而储能模量和损耗模量增加。0.5 mol/L NaCl溶解的欧洲鳗肌原纤维蛋白热诱导凝胶破断强度为98.81 g,高于低浓度NaCl溶解的蛋白热诱导凝胶。电泳结果表明,增加NaCl浓度会促进肌球蛋白重链和肌动蛋白的相互作用。根据傅里叶变换红外光谱和扫描电镜结果,发现0.5 mol/L NaCl溶解的肌原纤维蛋白热诱导凝胶具有最高的酰胺II/酰胺I强度比和最致密的网络结构。研究结果表明欧洲鳗肌原纤维蛋白在35 ℃时开始变性,提高NaCl浓度可以增强热诱导蛋白凝胶的强度和网络结构致密度,将为利用盐浓度和温度调控鳗鱼加热调理产品提供理论指导。 相似文献
84.
In seasonally breeding songbirds, variations in testosterone and song correlate with volume changes in brain nuclei associated with song, including the HVC. The authors tested whether singing can lead to activity-dependent increases in HVC volume by examining song output in starlings (Sturnus vulgaris). The authors manipulated males' environments so that only some were dominant with nestboxes, whereas others were not. Some of these males thus sang at higher rates and had larger HVC volume than others. The study was conducted over 2 years. In 1 year, males selectively occupied nestboxes but did not sing. HVC volume did not differ in these starlings, indicating that nestbox possession alone cannot increase HVC. The findings suggest that changes in song nuclei volume can be driven by changes in singing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
85.
J. Ventura-Traveset I. Stojkovic F. Coromina J. Benedicto F. Petz 《International Journal of Satellite Communications and Networking》1995,13(2):117-135
This paper deals with satellite payload architectures adequate for the provision of universal mobile telecommunication services (UMTS) by medium altitude earth and geostationary orbit (MEO and GEO) satellites. The payload concept introduced is based on a transparent transponder with onboard digital signal processing (DSP) operations and digital beamforming at the traffic carrier level (narrowband beamforming). The emphasis of the paper is on key design aspects and technology considerations of the payload processor unit (PPU), which includes multiplexing/demultiplexing and digital beamforming operations, and on the antenna and RF signal handling subsystems. For completeness, a review on the European digital technology is also presented. The development of such a payload architecture is in line with present and planned activities of the European Space Agency (ESA) for MEO and GEO orbit systems, which are also implicitly discussed in the paper. 相似文献
86.
The development of different muscles and adipose tissues during growth was investigated in commercial Japanese Black (JB) cattle and compared with breeds of the largest variation to be found in Europe. Animals, reared under typical conditions for Japanese and European beef production systems, gained similar body weights but different carcass composition at 24 months of age. The carcass of JB contained more adipose tissue and the least proportion of muscle. The longissimus muscle of JB developed extraordinary amounts of 23.3% intramuscular fat (IMF) at 24 months of age, compared from 0.6% to 4.7% in European breeds. The relationships between IMF content in the longissimus muscle and different adipose tissue weights indicate that a large amount of “waste fat” is accreted with every percent of IMF. However in JB, the good ability of IMF deposition is associated with relatively least development of “waste fat”, as a result of unique breed characteristics combined with special feeding system. 相似文献
87.
Sture Blomgren 《Building Research & Information》2003,31(6):474-478
Changes to the Swedish research landscape since 2001 are described including the re-organization of research councils, research programmes, the management and allocation of public funding research in Sweden, and the effects on built environment research. The reasons for these changes include the desire for increased integration with European Union research programmes, an increasing emphasis on inter- and multidisciplinary research, and the desire for research to contribute to economic well-being. Despite Sweden's high level of government investment in research, shifting priorities and an increasing number of applicants have resulted in reduced allocations for built environment research. This presents the challenging tasks to define and maintain core research capabilities within the built environment sector as well as to ensure adequate industry engagement with both the creation of the research agenda and the use of research outputs. 相似文献
88.
W. E. Gore G. T. Pearce G. N. Lanier J. B. Simeone R. M. Silverstein J. W. Peacock R. A. Cuthbert 《Journal of chemical ecology》1977,3(4):429-446
The three components of theScolytus Multistriatus aggregation attractant-4-methyl-3-heptanol (1), -multistriatin (2), and -cubebene (3)-were collected from beetles and elm wood by aeration, solvent extraction of host tissue, or solvent extraction of beetles and beetle parts. Bioassays and analysis of extracts demonstrated that (a) compounds 1 and 2 are produced by virgin females and 3 is host-produced, (b) cessation of the production of 1 is coincident with diminished attractiveness of females after they have been joined by males, (c) the release of 3 from elm wood is augmented by attacking beetles, and (d) the level of 3 is related to the condition of the wood, and fungal growth (particularlyceratocystis ulmi) may lead to increased levels of 3. Compound 1 was concentrated in the upper abdominal area and 2 in the abdomen tips, but neither component was in the hindgut. A gland opening through the vaginal palpi (a pair of sclerotized conical structures) was circumstantially associated with the release of 2. Compounds 1, 2, and 3 are regulatory agents that contribute to the initiation and maintenance of the beetle-elm-microorganism biosystem.Coleoptera:Scolytidae. 相似文献
89.
90.
湖北省公安厅主楼是一幢已投入使用数年的欧式建筑。扩建大楼建成以后,新旧建筑之间空间与立面关系显得协调得当,沿街立面显得更为完善,表明该建筑设计较为成功。面对各项制约条件的限制,建筑设计从场地规划、平面与立面设计,都做出了较为成功的选择。 相似文献