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1.
西北半干旱区集水型生态农业与生态环境的恢复重建 总被引：4，自引：1，他引：4
集水型生态农业是适应西北半干旱区自然资源特点的农业发展模式,是改善生态环境和提高土地生产力的结合点。通过采取使两者同时受益的关键措施,不但可以实现农民的脱贫,而且还可以使生态环境逐步得到恢复与重建,最终实现农业的可持续发展。 相似文献
2.
我国南方红壤丘陵区土壤质地黏重,透水性差,季节性降雨分布严重不足,极易发生水土流失;不合理的耕作措施加剧土壤侵蚀,导致土壤肥力下降,制约当地农业的可持续发展。1979年中国科学院桃源农业生态试验站(以下简称"桃源站")建站以来,系统开展了区域农业生态系统优化管理、农业整体效益的提高和建立区域农业综合发展的技术体系与优化模式,并进行示范推广,为南方红壤丘陵区农田生态系统耕地地力提升和水土流失治理、区域农业结构调整和生态环境改善提供重要理论和技术支撑。通过系统分析南方潜育性和次生潜育化水稻土的形成原因,为我国潜育性水田的治理提供技术支撑;研究红壤稻田生态系统可持续生产力与系统健康的协调机制,为稻田生态系统持续、高效生产提供理论依据和技术支撑;系统解析驱动稻田N2O和CH4排放关键过程的微生物作用机理,为我国农田温室气体减排提供重要的科学依据;系统解析我国农田生态系统土壤细菌和反硝化微生物的分布格局和主要驱动因素,为大尺度刻画我国农田土壤微生物群落组成机构及生态功能奠定基础;研究猪日粮功能性氨基酸代谢与生理功能调控机制,提升我国科学养猪水平和养猪业的健康可持续发展;探明了多年蔬菜连作对土壤氮素转化功能的影响及其微生物作用机制,并提出相应调控措施,为蔬菜土氮素的调控提供强有力理论依据和技术支持;研究典型农田生态系统养分流失特征及影响因素,构建丘岗复合农业生态系统氮磷拦截与生态消纳模式和稻田流失氮磷生态湿地消纳技术,为防控农田生态系统氮磷面源污染提供技术支撑;构建南方丘陵区坡地种草养羊与农牧资源循环利用模式并开展示范推广,服务当地农业可持续发展。未来,桃源站在中国科学院"率先行动"计划指导下,将为区域农业可持续发展作出更大的贡献。 相似文献
3.
王林 《大科技．科学之谜》2014,(2):222-223
毕节地区生态系统比较脆弱,加上近年来的无序开垦和不合理的用地,导致各种生态问题的出现,退耕还林工作刻不容缓。做好退耕还林工作,是改善生态环境,提高农业土地生产力的有效措施,也是实现可持续发展的基础。本文分析了毕节地区的基本自然环境,简要阐述了退耕还林的必要性,希望对毕节地区的退耕还林工作提供支持和帮助。 相似文献
4.
鲁瑞林 《大科技．科学之谜》2013,(23):301-302
摘要：随着经济的发展,人类活动日益频繁,对生态环境造成的影响也越来越严重,尤其是森林生态系统。当前,人们已经高度关注森林系统的作用和功能。党中央、国务院也制定了明确的方针：停止天然林采伐,恢复森林植被,维护生态系统的平衡和可持续发展。本文就天然林保护工作的重要性以及特点进行阐述,进一步提出针对性的措施,以提高天然林资源保护工作效率。 相似文献
5.
土壤侵蚀是水土保持的工作对象,水土保持就是在合理利用水土地资源基础上,组织运用水土保持林草措施、水土保持工程措施、水土保持农业措施、水土保持管理措施等构成水土保持综合措施体系,以达到保持水土、提高土地生产力、改善山丘区和风沙区生态环境的目的。以水土保持公路工程管理措施为切入点来论述土壤侵蚀及其与水土流失的关系。 相似文献
6.
土地整理的目标主要应是保护和改善生态环境,维护生物多样性及生态平衡,确保生态安全和土地生态系统可持续发展,土地整理的生态建设目标远比增加耕地的目标重要。转变传统的以增加耕地面积、改善生产条件为主要内容的可持续发展型现代土地整理发展,有效推进全省土地资源的可持续利用。 相似文献
7.
国内林业造林更新的现状及管理措施 总被引：1，自引：0，他引：1
近些年来,人类工业的快速发展对生态系统造成了严重的破坏,尤其是对森林资源产生的破坏和浪费,已经对人类的生产和生活产生了严重的威胁。为了有效的改善生态环境、减少对资源的破坏,我国进行了一系列的造林更新工程,其不仅在改善生态环境方面发挥了重要的作用,同时也为农牧产业的发展提供了更丰富的物质基础,更加关系着我国社会和经济的可持续发展。基于此,本文就主要针对国内林业造林更新的现状以及改进的措施进行简单的分析。 相似文献
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9.
张存生 《内蒙古科技与经济》2006,(12):16-17
实现我国农业可持续发展战略,必须抛弃旧的发展观,树立符合时代要求的新的科学发展观,走集约、高效、节约资源型的可持续农业发展道路。在实践中要因地制宜,实施区域发展战略,发展多种类型的可持续农业,对不同区域不同的经济发展水平,应采取不同的可持续发展模式和途径。同时,还要建立可持续发展的农业生态系统、可持续发展的农业技术系统和可持续发展的农业经济系统。 相似文献
10.
贵州东北部的地貌以喀斯特山地为主,具备生态环境敏感度高、承载容量低、土地石漠化严重等特点,为了改善该地区农业生态环境,促进农业经济持续稳定发展,应当合理建设农林复合生态模式,优化调整作物种植结构,提高土地利用率和劳动生产率。本文以思南县为例,对黔东北喀斯特山地农林复合生态建设模式进行探讨。 相似文献
11.
《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
12.
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
13.
《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
14.
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
15.
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
16.
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
17.
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
18.
Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献
19.
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
20.
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