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101.
本文从农业可持续发展、资源永续利用的原则出发,探讨了构建生态农业模式的原则,以山东省广饶县为例,系统分析了在该县构建和应用生态农业模式的优势条件和制约因素,具体论述了适合广饶县发展的三种生态农业模式:农—牧—沼型、上粮下渔型和草—畜—乳型生态农业模式。 相似文献
102.
Use of biofuels diminishes fossil fuelcombustion thereby also reducing net greenhousegas emissions. However, subsidies are
neededto make agricultural biofuel productioneconomically feasible. To explore the economicpotential of biofuels in a greenhouse
gasmitigation market, we incorporate data onproduction and biofuel processing for thedesignated energy crops switchgrass,
hybridpoplar, and willow in an U.S. AgriculturalSector Model along with data on traditionalcrop-livestock production and processing,
andafforestation of cropland. Net emissioncoefficients on all included agriculturalpractices are estimated through crop growthsimulation
models or taken from the literature. Potential emission mitigation policies ormarkets are simulated via hypothetical carbonprices.
At each carbon price level, theAgricultural Sector Model computes the newmarket equilibrium, revealing agriculturalcommodity
prices, regionally specificproduction, input use, and welfare levels,environmental impacts, and adoption ofalternative management
practices such asbiofuel production. Results indicate no rolefor biofuels below carbon prices of $40 perton of carbon equivalent.
At these incentivelevels, emission reductions via reduced soiltillage and afforestation are more costefficient. For carbon
prices above $70,biofuels dominate all other agriculturalmitigation strategies. 相似文献
103.
104.
105.
Ahmet?Kuba?Email author Fatih?Yilmaz Ya?ar?Akta? Nurcan?Met?N 《Quality and Quantity》2005,39(5):615-623
Multinomial Logit Model has analyzed the relationship between the frequency of visits to recreation areas and the motivational factors affecting the visits. Kastro Environment Preserving Site that is located in the Black Sea coast of Marmara region in Turkey, has been chosen as the site for this study. Kastro bay is a natural park that is visited only for recreational visits. The study has been conducted on a photogenic study group due to the proximity factor of Kastro bay close to Istanbul. Kastro bay is a popular recreational park due to its characteristic advantages such as a 200 m wide and approximately 2.5 km long beach and with its high quality vegetation. The vegetation type includes ash tree, oak tree, black pine, sand lily etc. Kastro bay is also the site for the Mediterranean seals (Monachus-monachus) which are at the level of extinction. Approximately 50,000 visitors visit the region during the months of July and August. It has been concluded that there is high direct correlation between the frequency of visits and the motivational factors. It has been determined that the visits are mostly based on the sea and the ecological tourism.Jel: O13, Q20, Q26, Q51, Q56, Q57 相似文献
106.
107.
Hakan Demirtas 《Statistica Neerlandica》2004,58(4):466-482
In this article, we demonstrate by simulations that rich imputation models for incomplete longitudinal datasets produce more calibrated estimates in terms of reduced bias and higher coverage rates without duly deflating the efficiency. We argue that the use of supplementary variables that are thought to be potential causes or correlates of missingness or outcomes in the imputation process may lead to better inferential results in comparison to simpler imputation models. The liberal use of these variables is recommended as opposed to the conservative strategy. 相似文献
108.
CMM模型和我国软件业生产过程标准化 总被引:1,自引:0,他引:1
CMM模型是国际上最流行的一种软件生产过程标准。本文比较了国内外软件业生产过程标准化的现状,分析了阻碍我国软件业开展CMM评估的原因,并在此基础上,提出在我国推行CMM标准亟待解决的几个主要问题。 相似文献
109.
面向电子商务的现代物流管理信息系统的开发 总被引:2,自引:0,他引:2
结合现代物流技术发展趋势,分析探讨了面向电子商务的现代物流管理信息系统的开发技术路线,关键技术内容,功能体系结构设计及分层逻辑模型设计。 相似文献
110.
Chris M. Alaouze 《Empirical Economics》2003,28(3):599-613
The modified logit model (Amemiya and Nold, 1975) is generalised to the case where the error term is autocorrelated. The
asymptotic distribution (as n →∞ and T →∞) of a feasible GLS estimator of β is derived. Tests of linear restrictions on β and the significance of ρ are presented.
The results of the applied work suggest that the factors which explain the pricing behaviour of manufacturing firms, as reported
in the tendency survey conducted by the Australian Chamber of Commerce and Industry and the Westpac Banking Corporation, include
historical inflation rates of up to 7 quarters and capacity utilisation.
First version received: March 2001/Final version received: July 2002
RID="*"
ID="*" The first draft of this paper was written while the author was on study leave at the Department of Econometrics, University
of Sydney, Australia. 相似文献