共查询到20条相似文献，搜索用时 468 毫秒
1.
湖南省耕地经营协调度时空演变 总被引：1，自引：0，他引：1
揭示区域耕地经营格局特征有助于从区域层面解读耕地经营模式特点,切实有效提出区域耕地利用转型的重点和发展方向。本研究基于“集约-规模-产能”三要素提出耕地经营协调度评价模型,并借助协调度函数和探索性空间数据分析方法揭示湖南省县域耕地经营格局演变特征。结果表明：①1990—2014年间,湖南省县域耕地经营协调水平整体较高,且空间格局差异明显：“长株潭”丘陵区集约指数较高,洞庭湖平原区规模指数较高,主要市辖区及其周边县域产能指数较高;②受不同地理区位和社会经济影响,湖南省县域耕地经营要素时空集聚特征存在明显差异:空间维度上,耕地经营协调度由“大集聚”向“小集聚”分布转变;时间维度上,规模指数自相关性较强且分布较集中,产能指数自相关性较弱且分布较分散;③从“投入-规模-产出”过程看,平原区呈现“高-高-高”特征,丘陵区表现“高-低-低”特征,山地区则为“低-低-低”特征。结合耕地经营格局时空演化特征成因,建议湖南各县域因地制宜地采用以粮食作物为主的集约经营模式,以经济作物为主的复合经营模式和特色作物经营模式。 相似文献
2.
耕地流转中农户行为的影响因素实证研究——基于江西省42个县市64个乡镇74个行政村的抽样调查 总被引：5，自引：0，他引：5
耕地流转是解决目前耕地经营过于分散与农业现代化建设矛盾的根本性措施,而农户作为耕地经营的直接主体,其行为在耕地流转决策中起着关键作用。本文以江西省为例,在对42个县市64个乡镇74个行政村抽样调查的基础上,运用主成分分析法和Pearson相关分析法,定量分析研究了农户耕地流出和流入的主要影响因素及其影响程度。研究表明:农户耕地流出和流入的影响因素及其影响程度是有明显差异的。影响农户耕地流出的主要因素依次是非农就业机会、耕地经营收益、农户家庭经济状况、耕地破碎度、区域经济发展水平、交通便捷度;而影响农户耕地流入的主要因素依次是家庭经济状况、耕地破碎度、耕地经营效益、非农就业机会、区域经济发展水平、交通便捷度。针对这一研究结果,本文最后提出了通过增强耕地流出驱动力和耕地流入源动力,来提高农户耕地流转积极性的一系列对策建议。 相似文献
3.
不同经济发展水平地区耕地利用集约度比较 总被引：2，自引：0，他引：2
揭示不同经济发展水平地区耕地利用集约度的时空差异及其驱动因素有助于了解农户土地投入行为对经济发展水平的响应状态,可以为实现耕地资源合理高效利用与农业可持续发展的政策制定提供参考。本文以上海市青浦区、长沙市长沙县和固原市彭阳县为例,运用实物形态法和综合指标法相结合的方法核算了不同经济发展水平地区2001—2016年的耕地利用集约度,然后采用岭回归模型分析了各地区耕地集约利用的驱动因素。结果表明：①2001—2016年,长沙县和彭阳县的耕地利用集约度呈波动上升趋势,而青浦区总体呈下降趋势,平均值从大到小为长沙县、青浦区、彭阳县;②耕地利用集约度包括资本集约度和劳动集约度,不同地区资本集约度在变化趋势和平均值大小顺序等方面与耕地利用集约度基本一致,而劳动集约度均呈波动下降趋势;③不同地区耕地集约利用的驱动因素存在差异,青浦区主要驱动因素为灌溉指数、农业政策和地均GDP,长沙县主要驱动因素是人均耕地面积、农业政策和地均GDP,而农业机械化水平是彭阳县主要驱动因素。不同地区的耕地利用集约度存在明显差异,并且其驱动因素也有所不同,政府相关部门应当根据当地实际情况采取相应措施以提高耕地集约利用水平。 相似文献
4.
不同城市化水平下中国粮食主产区耕地集约利用差异及其政策启示——以江西省和江苏省为例 总被引：7，自引：0，他引：7
本文提出从利用投入和产出效应2个方面测度耕地集约利用,并构建耕地集约利用评价的3种基本类型:粗放化型、集约化型和过度化型.以处于不同城市化水平下的江西省和江苏省两个粮食主产区为例,剖析两省2001年-2010年耕地(水稻种植)集约利用的差异及其政策启示.结果表明:①近10a来,城市化水平低的江西省单位耕地面积水稻种植总投入、省工性投入和增产性投入与城市化水平高的江苏省的差距明显缩小,其中省工性投入的差距最小,而江西省的水稻单产,尤其是水稻净利润在2010年进一步低于江苏省;②尽管江西省和江苏省耕地利用属于集约化型的年份均最多,但属于过度化型的年份比例偏高,分别为33.33％和22.22％,这说明两省尤其是江西省耕地产出效应没有同步跟进或者需要进一步跟进耕地利用投入;③江苏省应凭借自身优势推行农业现代化,江西省需增加以增产性投入为核心的农业投入和推行以加大种粮补贴、提高粮食收购价格为重点的惠农政策. 相似文献
5.
保护耕地资源生态多样性与提高耕地集约利用效益,对集约化农区耕地资源可持续发展具有重要意义.本文应用生态足迹方法,以新疆生产建设兵团45团灌区为例,对集约化条件下耕地资源生态多样性及其利用模式进行了分析.结果表明:1995年～2005年灌区耕地人均生态足迹呈逐年增加趋势,且与生态承载力基本协调;灌区耕地生态足迹的多样性指数呈现逐年下降的趋势,发展能力有待提高;耕地资源发展能力与多样性指数、GDP足迹三者之间关系达到极显著或显著水平.因此,积极稳妥的搞好集约化农区农业结构调整,走农林牧复合型农业发展模式,是促进耕地资源生态多样性、提高耕地资源集约利用效益的有效手段,最终建立资源节约型和环境友好型的耕地利用保障体系. 相似文献
6.
基于产业差异修正的工业行业土地集约利用评价研究——以江苏省为例 总被引：5，自引：2，他引：3
进行土地集约利用评价比较的前提是不同区域或行业间应具有可比性,本研究首先阐释了土地集约利用评价的可比性问题,然后设定了产业差异修正系数,在对江苏省各工业行业土地利用指标进行产业差异修正的基础上,评价了各工业行业及各区域的土地集约利用水平。研究结果表明:①土地利用指标经过修正后,行业间差异和区域间差异明显变小,个别指标出现了在不同区域间的优劣转变;②苏南、苏中、苏北工业行业土地集约度差异较大,从全省工业行业情况来看,土地集约利用总体水平偏低,黑色金属冶炼、造纸、石油加工、机械制造类、通信电子类行业土地集约度相对较高;③产业差异修正前后,工业行业土地集约利用评价结果存在一定差异,苏南工业行业平均土地集约度低于苏中。 相似文献
7.
基于多元数据集成的农用地集约利用评价-以北京市平谷区为例 总被引：2，自引：0，他引：2
本文以北京市平谷区为案例区,区别以往基于行政单元和统计数据的农用地集约利用评价方法,基于农户调研数据,结合土地利用现状、地形图、土壤图、农用地分等相关数据,构建基于多元数据集成的农用地集约利用评价指标体系,并以平谷区的农用地为评价单元,进行农用地集约度评价.结果表明:①平谷区农用地集约度受自然因素和社会经济因素的共同影响,农户的家庭收入水平、劳动力数量、农业收入比状况是影响农用地集约度的主要因素,地形和灌溉等自然本底是影响农用地集约度的基础条件;②平谷区农用地集约度主要处于比较集约和基本集约的水平,具有很大的提高潜力,平原和半山区的农用地集约度高于山区.构建基于多元数据的农用地集约利用评价指标体系,进行基于地块水平的农用地集约度评价,是一务可行有效的途径. 相似文献
8.
四重质量维度下的县域耕地质量评价方法研究 总被引：13，自引：0，他引：13
耕地利用与保护需要对耕地质量进行多维管理,多维耕地质量评价是耕地资源管理的重要依据,而县级尺度耕地质量评价是中国耕地质量管理的基础。根据耕地质量内涵,构建反映不同质量维度耕地质量的方法,是客观评价耕地多重质量的必然要求。本文以“需求-质量维度-指标-限制系数-耕地质量”理论框架为基础,构建了基于土壤、生态、环境和管理四个质量维度的县域耕地质量指标体系。利用多源多尺度数据,采用限制系数逐级修正的方法,以北京市大兴区为例进行了耕地质量评价方法的研究,并将评价结果与相关方法进行了对比分析。研究结果表明：①大兴区耕地质量处于中等偏上水平,环境质量是制约耕地质量提升的主要因素;②本研究考虑了耕地的环境质量,因此评价结果与基础地力评价和农用地质量分等成果有一定差异;③构建的耕地质量评价指标体系融合了现有的农用地质量分等指标、耕地地力指标、土壤环境指标等,具有较强的包容性和开放性;④根据非加和及限制因子原理,采用限制系数逐级修正的方法,客观反映了县域耕地质量差异。该评价方法不仅可以评价耕地质量,还可定量评价分维度质量,是对已有成果评价方法的有效补充,可以为中国耕地资源“数量、质量、生态”三位一体的管理需求提供有效支撑。 相似文献
9.
文章以贵港市区域建设用地为评价对象,选取利用强度指数(UII)、增长耗地指数(GCI)、用地弹性指数(EI)和管理绩效指数(API)构建评价指标体系,采用多因素综合评价法对区域土地节约集约利用状况进行分析评价。结果表明2015年贵港市区域建设用地节约集约利用评价总指数为72.70,土地利用状况处于中等水平,建设用地消耗量与社会经济发展协调程度还有待提升;贵港市所辖5个县(市、区)差异较大,土地利用状况最好为平南县,依次为覃塘区、桂平市、港南区和港北区。最后提出相关建议及措施,以期为促进贵港市建设用地的合理开发与利用提供科学依据与指导。 相似文献
10.
【目的】耕地集约化利用是保障农产品供给安全和耕地可持续利用的有效路径。科学辨析耕地集约化利用不平衡不充分的时空分异特征,精准把握耕地集约化利用存在的短板,对促进耕地资源潜力的挖掘,提升农业生产综合能力具有重要的现实意义。【方法】本文基于投入强度、利用程度、产出效益和持续状况4个维度测度2000—2020年全国及四大区域耕地集约化利用水平,采用Dagum基尼系数探究耕地集约化利用空间不平衡状况及结构来源,运用分位数标准化方法分析耕地集约化利用不充分状况及不平衡不充分的影响因素。【结果】(1)2000—2020年全国及四大区域耕地集约化利用水平差异较为显著,但总体均呈现不断提升的态势,耕地集约化利用程度较低省份对较高省份存在“追赶效应”。(2)全国耕地集约化利用不平衡状况总体呈现缩小态势,耕地集约化利用空间不平衡的主要来源是区域间不平衡,约占7成以上。(3)全国及四大区域耕地集约化利用不充分指数均呈现下降态势,总体不充分指数西部（80.94）>东北（74.33）>全国（68.14）>中部（60.16）>东部（55.72）。(4)耕地利用持续状况是导致全国及东部、中部... 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.
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
19.
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
20.
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