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961.
We studied the energy and economic flow of six types of homegardens in Sanjia village, SW China. Our study showed that the energy input of six types of homegardens averaged 99.11-175.65 x 1010J/ha, the energy output was 102.30-159.83 x 1010J/ha and the ratio of input/output ranged between 1:0.880-1:1.416. The ratios of input to output of home-gardens that prioritized cultivation of crops were higher than for homegardens that prioritized animal husbandry or other economic activities. The economic ratio of input/ output of six types of homegardens varied between 1:0.997-1:1.376 and the economic output ranged between 2480.0-10131.5 RMB/yr. We concluded that the homegarden systems of Sanjia village are high in the input and output of energy and cash flow, and can provide a basis for designing models of farm economy in rural subtropical areas.  相似文献   
962.
Analyzing the structure and functioning of the urban system revealed ways to optimize its structure by adjusting the relationships among compartments, thereby demonstrating how ecological network analysis can be used in urban system research. Based on the account of the extended exergy utilization in the sector of urban socio-economic system, which is considered as the composition of extraction (Ex), conversion (Co), agriculture (Ag), industry (In), transportation (Tr), tertiary (Te) and households (Do) sectors, an urban ecological network model is constructed to gain insights into the economic processes oriented to sustainable urban development. Taking Beijing city as the case, the network accounting and related ecological evaluation of a practical urban economy are carried out in this study in the light of flux, efficiency, utility and structure analysis. The results showed that a large quantity of energy and resources have to be consumed to maintain the structure and function of a city. The thermodynamic efficiencies of individual sector in Beijing remain at a low level. The social system in Beijing is a highly competitive network, and there are 8 competitive relations and only two mutualistic ones. The Domestic and Agricultural sector are the major controlling factors of the system. Moreover, the assessment results of Beijing are compared with the other three socio-economic systems, Norway, UK and Italy, and the ecological network function and structure comparisons are correspondingly illuminated and discussed. The conclusions indicate that the exergy-based network analysis can be refined to become an integrative tool for evaluation, policy-making and regulation for urban socio-economic system management concerning structure and efficiency at urban levels.  相似文献   
963.
近年来中国尤其是华北地区雾霾情况日趋严重.雾霾天气不仅对中国人民身体健康形成了威胁,并且在很大程度上对中国经济的正常健康发展形成了制约.本文探讨了中国雾霾的主要形成原因及雾霾对社会各方面造成的危害,根据雾霾成因分析经济产业调整的具体方式,以期优化经济产业结构,科学规划城市发展,从 源头治理雾霾,有效地促进经济产业持续健康有序的发展.  相似文献   
964.
当前节能减排是我国各级政府的主要工作任务."十一五"建筑节能目标占社会总节能目标的21%,建筑节能是我国节能工作的重要内容.本研究采用数量经济方法,建立建筑节能对建筑能耗的直接经济和环境影响测算模型.在合理的情景假定下.应用该模型测算,得出结论:"十一五"建筑节能目标的各项分解任务和总的节能任务可在3年内完成.3年中每年的建筑节能量对"十一五"期间平均每年节能任务的贡献率分别是17.28%,34.55%,51.83%.3年中每年因建筑节能而减少的主要污染物的排放量对"十一五"期间平均每年减排任务的贡献率分别是76%,152%和228%.最后提出既有建筑节能改造的节能任务可以适当增加的政策建议.  相似文献   
965.
Abstract: A price on carbon is expected to generate demand for carbon offset schemes. This demand could drive investment in tree‐based monocultures that provide higher carbon yields than diverse plantings of native tree and shrub species, which sequester less carbon but provide greater variation in vegetation structure and composition. Economic instruments such as species conservation banking, the creation and trading of credits that represent biological‐diversity values on private land, could close the financial gap between monocultures and more diverse plantings by providing payments to individuals who plant diverse species in locations that contribute to conservation and restoration goals. We studied a highly modified agricultural system in southern Australia that is typical of many temperate agriculture zones globally (i.e., has a high proportion of endangered species, high levels of habitat fragmentation, and presence of non‐native species). We quantified the economic returns from agriculture and from carbon plantings (monoculture and mixed tree and shrubs) under six carbon‐price scenarios. We also identified high‐priority locations for restoration of cleared landscapes with mixed tree and shrub carbon plantings. Depending on the price of carbon, direct annual payments to landowners of AU$7/ha/year to $125/ha/year (US$6–120/ha/year) may be sufficient to augment economic returns from a carbon market and encourage tree plantings that contribute more to the restoration of natural systems and endangered species habitats than monocultures. Thus, areas of high priority for conservation and restoration may be restored relatively cheaply in the presence of a carbon market. Overall, however, less carbon is sequestered by mixed native tree and shrub plantings.  相似文献   
966.
人力资本综合存量的度量方法有采用产出法分析,也有用投入法来分析;有从理论上推理,也有从经验数据上论证。分析方法有从教育人力资本角度出发,也有从健康人力资本角度出发。而绝大多数文献很少将教育和健康因素同时纳入考虑,仅分析其中一个方面无疑会带来测量的误差。若能同时考虑教育和健康,由新的度量方法产生新数据,由此带来新结论或是能对已有结论作进一步地论证,则是对以往文献研究的一个补充。因此,本文从四个维度建立新型人力资本综合测量体系,通过因子分析法对人力资本的综合水平进行了衡量。其中四个维度主要是指教育、劳动力再培训、身心健康和劳动力合理流动。在此基础上,把人力资本综合存量这一指标引入Solow模型中,构建扩展的Solow模型。利用扩展Solow模型,并结合最新人口统计数据进行实证分析,建立扩展的中国经济增长模型。研究发现人力资本和技术进步正逐渐成为我国经济增长的主要影响因素,劳动力数量对经济增长的影响在逐渐减弱。在我国经济发展的新阶段,如何在控制人口数量和提高经济发展水平方面协调各项工作成为当前的热点问题。为此我们针对教育投入,全民人口素质,中高端人才培养,经济增长方式创新等方面提出一些建议。  相似文献   
967.
ABSTRACT

Does climate change lead to violent conflict? This article reviews the existing literature connecting climatic conditions to conflict. It finds that the existing literature has not detected a robust and general effect from climate to conflict onset. Moreover, there exists scientific agreement that climatic changes can contribute to conflict under some conditions and through certain pathways. In particular, the recent literature offers considerable suggestive evidence that climatic changes can lead to conflict in countries and/or regions, which are dependent on agriculture, host politically excluded groups, and have ineffective institutions. Future research should focus not only on understanding of the pathways and contexts in which climatic changes are most likely to increase or exacerbate the risk of conflict but also work to understand the mechanisms by which climate variability and change might cause conflict.  相似文献   
968.
Abstract

The purpose of this article is to classify the regional economic types and development dynamics of small towns in suburb Beijing by applying the classification methods developed by Nelson’s method and Location Quotient method into 183 small towns in Beijing. Four types of small towns are thus identified, including urban agriculture dominated towns, manufacturing dominated towns, service industry dominated towns and comprehensive type towns with balanced economic development. Within the environment of geographical information system, the spatial distribution pattern of four types of small towns with their evolution trend is analyzed. The results indicate that four types of small towns have obvious ‘core-periphery’ spatial structure but with different functional orientations and evolution mechanisms. Based on this, the different development strategies for each type of small towns are summarized, providing a scientific reference for the differentiating planning and development strategies of these small towns.  相似文献   
969.
长江经济带经济演进的时空分析   总被引:1,自引:0,他引:1  
长江经济带横跨我国东中西部,与沿海经济带共同构成我国国土开发和经济建设的“T”字形宏观格局,是全国经济联系的中心区域,在我国经济发展中具有极其重要的战略地位。改革开放以来,我国率先实施了沿海经济发展战略,地处我国沿海经济带上的长江三角洲、珠江三角洲和环渤海地区得到了超常规发展,带动了全国经济的繁荣,而作为我国另一条发展主轴线的长江沿岸地区,区域发展战略及相关政策的提出则相对较晚。通过对长江经济带的时空分析,选择1992~2010年作为时间序列,以长江经济带作为空间序列,运用定性与定量相结合的手段,在概括长江经济带整体经济发展情况的基础上,分析长江经济带空间分异的变化过程,以期对长江经济带的发展提供可行性的线索和建议  相似文献   
970.
以安全生产相对指标工矿商贸十万就业人员生产安全事故死亡率为研究对象,通过文献调研分析,最终从经济发展、经济发展结构、经济活动水平和社会活动水平角度筛选出14个指标为观察对象,采用逐步多元回归分析法筛选出影响我国安全生产的主要经济社会发展指标为:第三产业增加值产值占GDP比重、第三产业就业人数占总就业人数的比重和固定资产投资增长速度,并建立了回归模型。应用弹性系数法对主要影响因素进行重要性排序,并推测工矿商贸就业人员十万人事故死亡率将保持持续下降的趋势。  相似文献   
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