首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
This paper discusses the efficiency of embodied spillover from North America and Japan to China. We suppose that embodied spillovers are transmitted by international trade. The efficiency of a country or an area utilizes the embodied spillovers depends on two aspects,which are AC(Absorption Capacity)and SS(Structural Similarity). The empirical analysis show that China's utilizing efficiency of the embodied spillovers from Japan(0.322 8) is larger than from American(0.187 3).  相似文献   

2.
Technological progress is the key competitive ability of a society.A society's technological progress depends on it's ability of research and development (R&D) and the absorption of R&D spillovers. Since China is a developing country, which is comparatively short of R&D expenditure and activity, it is absolutely necessarily to utilize R&D spillovers. This paper analyses the relation among destination-specific AC (Absorption Capacity) , source- and destination-specific SS (Structural Similarity) and embodied technology spillovers by one-sector and three-areas GTAP models. The conclusion is:Being 'neutral' in nature, the exogenous Hicks-Neutral Technical Progress shock uniformly reduces the input requirements associated with producing a given level of output of stuff.  相似文献   

3.
ABSTRACT Regional analysts often identify industry clusters according to a single dimension of industrial interdependence, typically by trading patterns as revealed in national or regionalized input–output data. This is despite the fact that the theory underpinning regional industry cluster applications draws heavily on Marshall's theory of external economies, including the important role of labor pooling economies and knowledge spillovers in addition to spatially co‐located suppliers. This article investigates whether industry clusters identified based on trading relationships (value chain clusters) are meaningfully different in industrial composition and geography than those derived from an analysis of occupational employment requirements (labor‐based clusters). The results suggest that value chain linkages are a weak proxy for shared labor requirements, and vice versa.  相似文献   

4.
杨芳 《中国农学通报》2018,34(34):151-158
基于我国蔬菜种业发展现状及各行业种业产值的测算方法,结合蔬菜业内产值的核算方法,本文运用农户端的数据,对2005 年-2015年我国蔬菜种业产值进行了核算。由于数据较难获取,本文采用间接算法估算其产值。经测算,2015年国内蔬菜种业产值达270.06亿元,其中,山东省的值最大,达40.88亿元。其次,河北省、江苏省、河南省的蔬菜种业产值均在20亿元以上。四川省的蔬菜种业产值最小,不足10亿元。按地域分析,中国东部地区的蔬菜种业产值最大,西部地区的蔬菜种业产值最小。2015年全国蔬菜种业产值排名前五的省份分别为山东省、河北省、河南省、江苏省和湖北省。2015年全国蔬菜种业产值最小的五省分别为海南省、天津市、北京市、青海省和西藏自治区。2005年-2015年东北部地区蔬菜种业产值先降后升,具体表现为2008年下降,2011年上升,主要受蔬菜种子价格波动的影响。东部沿海地区的蔬菜种业产值于2011年之后迅速上涨,主要受蔬菜种子价格波动及用种量变化的影响。此外,中东部地区的蔬菜种业产值略有下降态势。鉴于上述综合分析,各省蔬菜种业产值全国排名的变动主要受控于蔬菜种子价格、用种量及各年气候变动的影响,受蔬菜播种面积的影响较小。  相似文献   

5.
为研究裸大麦的遗传多样性,利用筛选得到的16条ISSR引物对收集的国内外102份裸大麦材料和1份皮大麦材料进行了遗传多样性分析,并分析了裸大麦地理分布与遗传多样性的关系。结果表明,16条ISSR引物共扩增出133条条带,大小在100~2000bp。不同引物扩增的条带数在3?15条,平均每条引物扩增出8.31条,多态性条带为113条,多态性的平均百分率为85.1%,103份材料的遗传相似系数(GS)在0.2817~6,提示裸大麦的遗传多样性较高。利用NTsys 2.1软件进行聚类分析,103份材料分为四大类,第一大类只分布在中国青海,第二大类分布在亚洲、欧洲、北美洲和非洲,第三大类分布在亚洲、北美洲和南美洲,第四大类仅分布在亚洲和北美洲,表明亚洲,尤其中国地区具有较高的遗传多样性。裸大麦的遗传多样性与其地理来源的相关性,为进一步研究裸大麦尤其是青稞起源提供了参考。  相似文献   

6.
North Korea remains a place of obscurity, mystery and even of imminent threat in popular imagination of East Asia and America. In this article, we explore existing representations of and discourses around North Korea and argue for a different framework to consider how North Korea is a critical participant in the contemporary world. Drawing on our respective fieldwork in Dandong, China, throughout 2006 to 2014, the article suggests a new way of thinking about issues surrounding North Korea.  相似文献   

7.
美国奶业新特点、新趋势及对中国的启示   总被引:1,自引:0,他引:1  
美国奶业发展历史悠久,其生产端、消费端乃至流通贸易方面长期积累的丰富经验,对中国奶业振兴具有一定的参考价值。笔者对2000年以来美国奶业生产、价格、消费、贸易等方面所呈现的新特点进行分析,对奶业相关的支持政策及其变化趋势进行梳理。研究发现,近年来,美国奶牛场数量向北部和西部集中,500头以上规模化牧场成为主流,奶牛存栏增加;技术进步推动奶牛单产突破10 t,生鲜乳产量接近1亿t。基于分级定价的乳成分定价机制不断完善,近5年生鲜乳价格低位运行,2019年快速复苏。乳制品加工业向龙头企业集中,奶酪是主要加工产品。乳制品消费逐年增长,年人均消费量达292.90 kg,奶酪是主要增长点且增速加快。乳制品贸易波动增加,出口目的地集中在北美、东亚和东南亚地区,品类以奶粉、奶酪和乳清为主。奶业产业支持政策广泛涵盖生产、消费、贸易等各环节,各政策间功能互补、协调配套,形成了强大的政策合力与综合效能。美国奶业在产业组织、运行机制、政策配套等方面的经验与做法,对推动完善中国奶业利益联结机制、优化生鲜乳价格形成机制、完善奶业支持政策体系和培育乳制品消费习惯等方面具有重要启示。  相似文献   

8.
Spring sown bread wheat is grown at high latitudes in Europe, Asia and North America. However, it is not clear what the associations are among environments, particularly in Asia and North America, and whether or not cultivars developed in one region may adapt in another. A yield trial comprised of cultivars developed in northern Kazakhstan, western Siberia, the Canadian Prairies, northern USA, northeastern China and broadly adapted genotypes bred by CIMMYT in Mexico was planted in all the above mentioned environments in 2002–2004. In general, cultivars performed best within the regions they were developed. However, cultivars developed in northern Kazakhstan/western Siberia were the most broadly adapted at high latitudes; they were not significantly different for grain yield from the locally developed cultivars in both China and Canada. Stronger photoperiod response, greater plant height and larger seed weight appeared to be key adaptive features of these materials. At lower latitudes, the Kazakh/Siberian cultivars were significantly lower yielding than all other materials. When low latitude Mexican sites were removed from the analysis, the Chinese locations tended to associate, whereas most Canadian and Kazak/Siberian locations were negatively associated with those from China. SSR analysis of the cultivars from each region split the materials into two general groups, one based on North American cultivars and one comprised of Kazakh/Siberian and Chinese cultivars. Lines developed in Mexico were spread across these two groupings. Evidence suggests that considerable scope exists to improve bread wheat adaptation at high latitudes globally through intercrossing materials originating from Asia and North America.  相似文献   

9.
Although climate change has been modifying grassland ecosystems for a long time, few studies on grassland ecosystems have focused on large‐scale responses to climate change. Hence, grassland net primary productivity (NPP) from 1981 to 2010, as well as its variations in China, North America, Europe and Australia, was assessed and compared using a synthetic model in this study. Subsequently, the correlations between the NPP of each grassland type and climate factors were evaluated to reveal the responses of grassland eco‐systems to climate change. The results showed that North America, which has the largest area of grassland ecosystems, exhibits maximum grassland NPP of 4225.30 ± 215.43 Tg DW year?1, whereas Europe, which has the least area of grassland ecosystems among the four regions, exhibits minimum grassland NPP of 928.95 ± 24.68 Tg DW year?1. Grassland NPP presented an increasing trend in China and Australia, but decreasing in Europe and North America from 1981 to 2010. In addition, grassland NPP is positively correlated with mean annual precipitation, but demonstrates notable differences with mean annual temperature. In conclusion, climate change has a significant role in explaining the spatiotemporal patterns of and the variations in grassland NPP in the four regions.  相似文献   

10.
利用生物测定和高效液相色谱方法研究紫花苜蓿(Medicago sativa L.)自毒性现象,并评价不同品种苜蓿自毒性差异。结果显示,苜蓿叶浸提物抑制受体苜蓿vector的胚根生长,对照与所有处理的差异均达到极显著水平(P<0.01)。50个苜蓿品种按自毒性强度可分为3大类9个小组,自毒性最弱的组只有一个品种,为Key;最强的组有GS20001X、超级阿波罗、射手、NS00-32、牧野、WL232HQ共5个;其余品种分布在上述两组之间。在苜蓿叶浸提物中检测到香豆素、邻香豆酸、间香豆酸和对香豆酸4种目标酚类物质。  相似文献   

11.
为研究大宗淡水鱼养殖和产业空间优化问题,基于标准椭圆模型,以大宗淡水鱼产量最多的草鱼为研究对象,2006—2016年国内31个省级行政区草鱼产业养殖规模为基准,分析草鱼产业发展的空间分布格局(集聚度、重心、范围、方向)、演变特征及影响因素。研究表明,国内草鱼产业空间演变呈离散化集聚发展态势。长江流域中上游地区产量的稳步增加,西北干旱、半干旱地区的草鱼养殖扩大,推动了草鱼产业标准椭圆向西、向北偏移。草鱼产业发展的空间布局呈现分散化集聚,草鱼养殖逐渐由粗放型养殖向精细化养殖方式转变,产业发展在空间上存在由中东部向西、向北传递机制。这主要是草鱼具有良好的环境适应性、中西部成本较为低廉和市场扩大效应导致的。  相似文献   

12.
马铃薯品种遗传多样性分析   总被引:4,自引:0,他引:4  
为解析一套(559份)从世界各国收集的马铃薯种质资源的遗传多样性,用16个表型性状和36个SSR标记进行了聚类和多样性参数分析。对454份表型数据完整材料的UPGMA聚类分析表明,在欧氏距离14.66处被聚成2个类群(A_1和A),其中A_1在欧氏距离12.74处被分为A_(11)和A_(12)亚群;454份材料在欧氏距离11.73处被划成9个类群,包括4个小类(A、B、C和H)和5个大类(D、E、F、G和I),其中类群I所包括的材料占总数的57.5%,该结果较好地揭示了马铃薯种质材料之间的形态差异,区分生态类型不同和遗传差异明显的亲本。36个SSR标记在559份材料中共检测出134个多态性位点,每对引物检测1~7个等位变异,平均3.72个,引物多态性信息量(PIC)为0.1545~0.7743,平均为0.5783,说明品种间有丰富的遗传多样性。NJ系统进化树分析表明,559份材料可分为3个大群。类群I为一个混合群,各地区品种均有分布,包括133份马铃薯材料,占总数的23.8%;类群II中欧洲、北美及中国东北和西北地区的材料所占比重较大,数量为187,占33.5%;类群III中北美、南美以及中国东北和西南地区马铃薯材料所占比重较大,包含239份材料,占42.8%。表型性状聚类与SSR分子标记聚类结果相似,均与地理位置有很大相关性,应结合共同用于评价马铃薯品种遗传多样性。  相似文献   

13.
Russia presents an interesting case of a country which has strived to implement innovation policies since the transition period but so far has achieved mixed results. This study aims to analyze the impact of knowledge production and knowledge spillovers on regional growth in Russia within a framework of endogenous growth models. Applying GMM and spatial error panel modeling techniques to Rosstat data for 80 Russian regions from 2005 to 2013, the authors test the hypothesis about the relevance of R&D and expenditure on technological innovations (H1) and the hypothesis about the relevance of knowledge spillovers (H2) on the growth rates of GRP per capita. Hypothesis 1 was confirmed while Hypothesis 2 was rejected, indicating the absorptive capacities of innovatively lagging regions were not high enough for effective adaptation of new technologies from technologically innovative regions. Inclusion of indicators related to additional channels of knowledge diffusion in regressions resulted in the relevance of FDI and imports of goods and services for regional growth. Results of the study could form the basis for developing innovation policies for the Russian regions.  相似文献   

14.
我国核桃发展现状及贮藏研究概况   总被引:4,自引:0,他引:4  
我国的核桃产量居世界第一。核桃是我国重点发展的产业之一。介绍了我国核桃产业的发展现状、当前的主要贮藏方式、影响核桃贮藏最重要的关键因素以及国内外的研究概况。  相似文献   

15.
以我国31个省区市为研究对象,使用2012—2019年面板数据,运用三阶段DEA模型测算我国生鲜农产品冷链物流效率。结果表明:我国生鲜农产品冷链物流效率呈逐年上升趋势,大部分地区生鲜农产品冷链物流产业处于规模效率递增阶段;信息化水平、基础设施建设水平、对外开放程度,以及创新发展水平对投入指标的松弛变量产生了显著的影响;华中、华东、华北和华南地区的生鲜农产品冷链物流效率高于全国平均水平,东北、西南和西北低于全国平均水平;规模效率是制约生鲜农产品冷链物流效率提高的最主要因素。针对上述结果提出了相应的对策建议,可为国家或地方政府制定冷链物流产业发展政策提供决策依据与参考。  相似文献   

16.
ABSTRACT Competitiveness can be defined as the ability of an economy to maintain stable or increasing market shares in an economic activity while sustaining stable or increasing living shares for those who participate in it. Government policy in all countries has strong effects on competitiveness. With the turn away from a Cold War economy the Clinton Administration has pursued a technology policy explicitly linked to the quest for heightened national competitiveness. It is based on a rejection of Reagan-Bush era analyses of the competitiveness problem, which centered on cost reduction in industry. There are many different forms of technology policy for competitiveness, however. Some center on labor quality, while others center on technological spillovers between industries. An effective policy should promote technological spillovers in the economy. All such policies, moreover, are only effective if they are organized and governed properly. The Clinton-Gore policy has many different programs and methods of governance. This paper argues that it should reinforce the regional level of organization of technology policy formulation and implementation.  相似文献   

17.
区域农业结构的灰色关联分析与优势产业的发展   总被引:7,自引:3,他引:4  
吴凯  卢布  袁璋 《中国农学通报》2006,22(10):397-397
此文应用灰色关联分析、相关分析对中国中部地区三大区域的农村经济结构、农林牧渔业总产值结构、粮食产量结构、肉类产量结构进行了初步分析,确定了贡献较大的因子,并用时序模型对所研究的系列进行了模拟和预测。中部地区农业结构的现状是:非农产业的贡献越来越大,农、牧业为主的产值结构,中国玉米、小麦、稻谷、大豆优势产业带,中国肉牛、肉羊生产优势区。该区三大区域应根据各自的资源优势,因地制宜、大力发展其优势粮食作物、优势牛羊业和优势非农产业,进一步促进其农业和农村经济的可持续发展。  相似文献   

18.
This article briefly introduc input-output analysis, and its application to analyzing the housing industry of Japan, and the actuality and challenges in the development of housing industry in China; discusses the importance of analyzing input and output and creating its input-output table between Chinese housing industry and its correlative industries; roughly analysed the influence of the housing industry of Chongqing on its district economy and the action of inducing the development of its correlative industries.  相似文献   

19.
通过回顾工业革命的历史,指出现代化的本质是工业化和城市化,是把农村人变为城市人、把农民变为工人、把农村变为城镇的过程,现代农业是市场化、工业化和城市化的农业;提出农业的根本出路在于工业化、城市化的发展,根本动力在于工业化、城市化过程中所产生的市场新需求;分析了2000年以来中国农产品加工业的发展,结果表明,2011年年底我国农产品加工业总产值已经达到14.7×10~4亿元,占GDP总量的32%,与农业产值之比达到1.7:1,已经取代传统种养殖业成为农业的主体,成为国民经济的战略性接替产业和支柱产业;指出现代农业的发展将主要依赖于农产品加工业的发展,未来30年是我国农产品加工业发展难得的战略机遇期和高速发展期。针对发展中存在的问题,从政府的地位和作用、现代农业发展规划、农业科技发展思路,以及农产品加工科技公益类性质等方面,提出了政策建议。  相似文献   

20.
中国养殖业中的外来物种入侵现象调查分析   总被引:5,自引:0,他引:5  
采用文献调研、实地考察与专家咨询相结合的方法对调查了中国养殖业中外来物种入侵现象进行了调查。初步查明了中国养殖业中外来入侵物种种类共计27科40种,其中外来入侵水生植物、陆生植物、无脊椎动物、脊椎动物分别为5种、10种、3种、22种;来源于美洲、欧洲、非洲、亚洲和中国不同生态环境的分别有22种、3种、6种、3种、6种;中国养殖业中的外来物种入侵途径以不当的有目的的引入为主;外来物种入侵已对中国生物多样性、人民健康和经济造成了严重影响。针对中国养殖业中造成外来物种入侵的原因,需要采取必要的防治措施以促进中国养殖业的顺利发展。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号