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运用Global Malmquist-Luenberger指数评价2009-2016年全国30个省级行政区交通运输业碳排放全要素生产率的变化情况,基于泰尔指数和变异系数分析其区域差异及形成原因,并结合GML指数的分解指数探讨影响全要素生产率变化的因素.结果 表明,研究期间中部与西部地区交通运输业碳排放全要素生产率呈现下降趋势,并导致全国全要素生产率总体水平降低;全国全要素生产率变化的区域差异主要来源于四大经济区域内部差异,且西部和东北地区内部差异的贡献率较大;虽然影响全要素生产率变化的主要因素存在差异,但各地区全要素生产率的进步均受到技术发展的限制. 相似文献
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【目的】揭示耕地利用生态全要素生产率增长的动力源泉，探究耕地利用生态全要素生产率的提升路径，为促进耕地利用绿色转型提供政策参考。【方法】将Meta-frontier分析框架与Non-radial Malmquist-Luenberger生产率指数相结合，构建Meta-frontier Non-radial Malmquist-Luenberger(MNML)生产率指数模型，从而有效解决了如何在技术异质性框架下对能够考虑非期望产出的耕地利用生态效率和生态全要素生产率的评价问题。【结果】利用MNML生产率指数对1997—2019年中国耕地利用生态效率和生态全要素生产率进行评价，研究发现：(1)共同前沿下中国耕地利用生态效率均值为0.350，仍有65.0%的可改善空间；除东部地区之外，中、西部地区群组前沿下的耕地利用生态效率值远高于共同前沿下的耕地利用生态效率值。(2)中国耕地利用生态全要素生产率年均增长4.0%，并且主要由耕地利用技术进步驱动，而耕地利用技术效率则阻碍了耕地利用生态全要素生产率增长。(3)中国耕地利用生态全要素生产率呈东、西部高，中部低的分布特征，且东、中、西部地区耕地利用... 相似文献
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本文运用Malmquist-Luenberger指数法测度了我国各地区1995-2007年碳排放约束下全要素生产率增长及构成.估计了在碳排放约束和传统情形下全要素生产率指数及其构成,并检验两种情况下全要素生产率及其构成的差异.主要结论有:碳排放约束条件下东部地区TFP增长最快,西部地区增长最慢,中部地区则均介于二者之间;我国全要素生产率增长水平不断提高,技术效率变化是全要素生产率增长的源泉,但在碳排放约束情况下不及传统全要素生产率高;在28个省市区中,有8个地区至少移动生产可能性边界1次;本文还实证考察了人均GDP、工业化水平、技术无效率水平、劳均资本、能源强度和开放度等因素对在碳排放约束条件下全要素生产率影响效果,并据此给出了一些政策性建议. 相似文献
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环境管制与中国农业全要素生产率增长研究 总被引：1，自引：0，他引：1
利用中国省际面板数据,将农业面源污染和碳排放作为"坏产出"指标纳入农业全要素生产率测算中,采用Malmquist-Luenberger指数分析2001—2010年考虑环境因素下中国30个省市区的农业全要素生产率及其分解成分,并探讨考虑环境因素下中国农业全要素生产率演变的影响因素。研究结果表明:考虑环境因素的中国农业全要素生产率呈增长趋势,但表现出较大的波动性,其动力主要来源于技术进步;从地区差异来看,考虑环境因素下中国农业全要素生产率呈现东、中、西部地区依次递减;农村经济发展水平、农业产业结构变动、农业基础设施投资对考虑环境因素下中国农业全要素生产率有显著影响,而环境管制影响则不显著。 相似文献
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选取2008—2018年成渝地区双城经济圈所含16个城市的数据,基于DEA方法的Malmquist-Luenberger指数模型,在传统全要素生产率(TFP)基础上纳入工业生产中能源投入和环境污染产物变量指标,对成渝地区16个城市的工业绿色全要素生产率(GTFP)及其分解项进行测算,并讨论其不同时段下的空间溢出网络结构。结果显示：污染物排放阻碍地区工业GTFP提高,绿色技术进步对GTFP提升有显著促进作用,成渝地区整体绿色技术效率较低。从整体看,空间分布呈现出聚集性特征和空间关联性;从局部看,眉山、泸州、南充、绵阳等GTFP较高的城市表现出溢出效应,重庆的GTFP增速放缓的主要制约因素是绿色技术效率。最后,基于分析结果,从加强工业自主创新能力、优化产业结构以及优化调整环境规制政策等三个方面提出了政策建议。 相似文献
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基于绿色增长视角创新研发方向的约束,将能源消耗和环境污染纳入工业企业研发创新绩效评估框架中,运用方向性距离函数和Malmquist-Luenberger生产率指数测度2005—2011年我国30个省级区域的工业企业研发创新相对效率和全要素生产率变动。研究发现:考察期内工业企业研发效率偏低,均值为0.553;研发全要素生产率增长率为3.6%,由研发创新技术进步和技术效率改善等因素所致;将研发效率与研发全要素生产率指数相结合,按竞争力强弱和进步节奏快慢将30个省级区域分为4种类型。 相似文献
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《资源科学》2019,(5)
绿色发展将成为中国未来农业增长的重点内容,衡量农业绿色生产率有利于正确判断当前绿色发展的阶段特征。本文引入碳排放交易理论,将考虑了碳排放成本的农业绿色GDP作为产出,将农业生产中的氮磷流失作为一种要素投入,运用参数随机前沿函数模型(SFA)测算并分析了中国农业2000—2015年的省(市、区)绿色全要素生产率(GTFP)变化指数,并与传统全要素生产率(TFP)进行了比较分析。结果表明,研究期内中国农业GTFP年均下降0.14%,主要因2008/2009年前绿色技术的"退步"造成;从时间趋势和空间分布呈现明显的波动性特征以及地区之间的梯度性特征。此外,农业TFP变化指数优于GTFP变化指数,年均增长0.02%,主要得益于技术进步驱动,但传统技术效率处于年均下降状态。改变重产出的研发理念、加强农业绿色技术研发,进而提高传统投入要素的技术效率水平是中国未来提高农业绿色生产率的关键。 相似文献
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长江经济带城市土地利用效率评价 总被引：4，自引：0，他引：4
城市土地资源的合理有效利用是经济可持续发展的重要保障。以长江经济带108个地级及以上城市为研究对象,运用三阶段DEA模型和Malmquist指数对2005—2015年城市土地利用效率进行静态和动态分析。研究结果表明：①剔除外部环境和随机误差因素对城市土地利用效率影响之后,综合效率和纯技术效率显著提高,规模效率、技术进步和全要素生产率呈现不同幅度下降;②土地利用效率整体处于较低水平,空间格局呈现下游地区显著高于中、上游地区,长江沿线以南地区显著高于以北地区的分布态势,与纯技术效率联系密切;③土地利用规模报酬空间分异明显,长江中上游地区多处于规模报酬递增阶段,而中下游地区投入冗余情况显著;④土地利用全要素生产率年均下降0.7%,前期受到规模效率和纯技术效率的抑制,后期由技术进步推动发展,各城市土地利用效率趋于均衡。 相似文献
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A research group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol-a chemical found in the skins of red grapes in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said. 相似文献
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《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
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Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
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《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
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A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
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Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
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Active biological molecules functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery disease diagnosis therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction. 相似文献
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Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
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Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
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Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献