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巴西是农牧业大国,农业是巴西经济的支柱产业。自20世纪70年代开始,巴西经历了土壤改良和热带动植物生产系统,免耕直播,以及农林牧一体化生产3次技术革命;巴西的大豆也经历杂交大豆、热带大豆和转基因大豆3次技术变革。巴西农业技术变革主要依赖于由政府主导的农业技术创新管理体制与运作机制,以及由科技部牵头的国家科技创新发展战略。未来,巴西还将在转基因大豆、热带水稻栽培、动物疫病防控和病虫害防治等技术上寻求与中国的合作。 相似文献
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中国是大豆发源地,大豆一直是我国主要的粮食与油料作物之一,建国以后很长一段时期内我国的大豆面积、产量与出口量一直处于世界首位。但是20世纪90年代以来,我国在大豆高产优质品种选育及配套高产高效栽培技术研究、试验、组装与推广上发展缓慢,单产水平上不去,导致种植大豆比较效益低。同时,美国、巴西、阿根廷等国家大豆发展迅猛,在国际大豆市场的份额越来越大,对我国大 相似文献
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主要国家大豆压榨企业布局特征及其成因——以美国、巴西、中国为例 总被引：1，自引：0，他引：1
大豆是一种重要的农产品资源,压榨行业是大豆产业链上的重要环节,它的原料来自大豆种植业,生产的豆粕主要用作饲料业和畜牧业的蛋白原料。自1996年以来,中国大豆进口量不断增加,是全球最大的大豆压榨国,大豆压榨企业布局发生了重大变化。美国和巴西是世界上最大的大豆生产国,也是主要的大豆压榨国,对比分析美国、巴西及中国大豆压榨企业布局特征,对指导中国未来大豆压榨企业投资布局具有重要意义。本文根据项目组20多年持续收集的相关资料,以及美国农业部、巴西植物油加工协会的资料,对比美国、巴西和中国的大豆供求基本特点、大豆生产布局、畜牧业和饲料业分布、大豆压榨企业和产能布局特点发现,美国、巴西的大豆压榨企业主要集中在大豆主产区,并与其国内豆粕市场空间高度重合,呈现"大集聚、小分散"的布局形态;而中国大豆压榨企业布局和大豆制品销区在空间上不完全重合,逐渐形成了以沿海港口城市为压榨核心,以长江、哈大铁路等交通运输线路扩散的带状布局形态。区域畜牧业、饲料业发展决定着豆粕市场需求空间,但是大豆原料供给与豆粕需求在空间上往往存在差异,除了不同国家和区域的产业政策外,大豆原料及豆粕的运费成本、豆粕的市场潜力、区域内大豆压榨产能规模及企业间分工协作所产生的集聚效应是造成大豆压榨企业空间布局形态存在巨大差异的主要原因。 相似文献
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大豆生产及贸易的生态经济效应评价 总被引：1，自引：0，他引：1
全球化进程的加快促使全球农产品贸易量迅速增加,由此引起的环境及社会经济效应也逐渐成为学术界关注的焦点。本研究使用多属性效用理论,分别从生态和社会经济两个方面对我国及我国大豆进口来源国的大豆生产及贸易的效应进行了定量分析和评价。通过计算结果可以看出,巴西、美国大豆生产和贸易的生态效应和社会经济效应均较高,而阿根廷大豆生产及贸易则处于低生态效应、高社会经济效应的范围,相比较而言,我国大豆生产和贸易的生态和社会经济效应值均低于这三个大豆进口来源国。因此,从全球角度来看,我国大豆进口降低了全球大豆生产的生态环境负效应,提高了大豆出口国的社会经济效应。但是对于我国而言,要保证大豆供给的可持续性,一方面应提高国内大豆的生产效率和社会经济价值,另一方面应采取相应措施保障进口大豆来源的可持续性。 相似文献
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大豆是一种重要的农产品资源,压榨行业是大豆产业链上的重要环节,它的原料来自大豆种植业,生产的豆粕主要用作饲料业和畜牧业的蛋白原料。自1996年以来,中国大豆进口量不断增加,是全球最大的大豆压榨国,大豆压榨企业布局发生了重大变化。美国和巴西是世界上最大的大豆生产国,也是主要的大豆压榨国,对比分析美国、巴西及中国大豆压榨企业布局特征,对指导中国未来大豆压榨企业投资布局具有重要意义。本文根据项目组20多年持续收集的相关资料,以及美国农业部、巴西植物油加工协会的资料,对比美国、巴西和中国的大豆供求基本特点、大豆生产布局、畜牧业和饲料业分布、大豆压榨企业和产能布局特点发现,美国、巴西的大豆压榨企业主要集中在大豆主产区,并与其国内豆粕市场空间高度重合,呈现“大集聚、小分散”的布局形态;而中国大豆压榨企业布局和大豆制品销区在空间上不完全重合,逐渐形成了以沿海港口城市为压榨核心,以长江、哈大铁路等交通运输线路扩散的带状布局形态。区域畜牧业、饲料业发展决定着豆粕市场需求空间,但是大豆原料供给与豆粕需求在空间上往往存在差异,除了不同国家和区域的产业政策外,大豆原料及豆粕的运费成本、豆粕的市场潜力、区域内大豆压榨产能规模及企业间分工协作所产生的集聚效应是造成大豆压榨企业空间布局形态存在巨大差异的主要原因。 相似文献
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“大豆优异基因资源发掘及其基因组研究” 立项背景和意义 总被引：3，自引：0，他引：3
大豆是重要的粮食和油料作物,在我国国民经济发展中具有重要地位
。在中国加入WTO的形势下,我国大豆面临着生产落后、供给严重不足、国内大豆产业受到
进口转基因大豆的严重冲击的局面。我国是大豆的起源中心,收集保存的大豆资源蕴藏着丰\\r
富的有益基因。开展大豆优异基因资源发掘、大豆基因组序列测定与生物信息学分析、大豆
优异基因的分子标记、定位与克隆等关键科学问题研究,将推动大豆的分子生物学研究并提\\r
高大豆的分子育种水平,为大豆遗传改良奠定坚实的理论基础。针对这些内容,2003年国家
自然科学基金委员会设立了重大项目“大豆优异基因资源发掘及其基因组研究”。 相似文献
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张海 《科技成果管理与研究》2010,(7):20-20
吉林省农业科学院杨光宇研究员从事大豆资源研究工作30余年，在大豆资源研究方面创造了非凡的业绩，在国内外该研究领域有相当重要的影响，为吉林省乃至我国的农业发展做出了突出的贡献。 相似文献
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我国野生大豆研究进展及展望 总被引：3，自引：0，他引：3
一年生野生大豆(Glycine soja)是栽培大豆(G.max)的近缘祖先种,其地理分布限于亚洲东部,包括俄罗斯、日本、朝鲜和中国。1978年,吉林省农业科学院在全国率先开展了野生大豆考察,搜集资源800份,在我国大豆界引起巨大的反响。1979-1980年,我国开展了全国性的野生大豆资源考察,从25个省区搜集资源5000余份。到目前为止,已搜集到野生大豆资源6000余份,占世界总数的90%以上。这些野生大豆资源中蕴藏着品质好、抗性强、丰产性好等一大批优异基因型,为世界大豆界所瞩目。野生大豆资源的搜集不仅为大豆品种的遗传改良提供了新的基因来源,同时也为大豆起源、演化及分类等研究提供了丰富的研究素材。因此,中国野生大豆研究具有重要的学术价值和实践意义。近年来,我国野生大豆的研究取得了重要的进展。 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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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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《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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《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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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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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
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Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
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Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
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《中国科学院院刊(英文版)》2014,(3)
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence 相似文献