This review presents a comprehensive techno-economic and life-cycle assessment of sustainable aviation fuel(SAF)production from biomass.The critical need for transitioning towards environmentally sustainable alternati...This review presents a comprehensive techno-economic and life-cycle assessment of sustainable aviation fuel(SAF)production from biomass.The critical need for transitioning towards environmentally sustainable alternatives for liquid fuel and aviation industry is first discussed.Key insights encompass the evolutionary progression of biofuel production from first-generation to second-generation biofuels,with a focus on utilizing non-food sources like woody biomass for enhanced sustainability.Available data from the literature on techno-economic assessments of various SAF production pathways are analyzed including production costs,conversion efficiency,and scalability.Moreover,results of lifecycle assessments associated with different SAF production pathways are presented,providing essential insights for decision-making processes.The challenges of scaling up woody biomass-based SAF production are discussed based on the assessment results,and recommendations are proposed to steer stakeholders towards a greener and more sustainable trajectory for aviation operations.展开更多
The concept of the e-marketplace is introduced.Considering a supply chain with a single manufacturer who sells a single item in an e-marketplace,an analytical model for the use of the e-marketplace in a supply chain i...The concept of the e-marketplace is introduced.Considering a supply chain with a single manufacturer who sells a single item in an e-marketplace,an analytical model for the use of the e-marketplace in a supply chain is provided.Assuming the market demand is stochastic and price-dependent,the conditions under which the manufacturer and the e-marketplace owner share the market in equilibrium is developed.The existence and uniqueness of the optimal selling price,quantity and transaction percentage are proved.An integrated supply chain is put forward,and then the efficiency of supply chain coordination is studied by comparing the integrated supply chain with the decentralized supply chain.To gain further insights on the theoretical models,extensive simulations are then carried out.展开更多
[Obective] This study amied to evaluate the direct usage value of Liangzi Lake, like plants and animal resources and water storage value. [Method] It was measured through the market value method. The physical environm...[Obective] This study amied to evaluate the direct usage value of Liangzi Lake, like plants and animal resources and water storage value. [Method] It was measured through the market value method. The physical environment was introduced and the productivity of the lake was investigated both through the literature materials and the investigations. The market value method was clarified in this paper as well as its operation process and the application fields. [Result] Based on the introduction of the current situation in Liangzi Lake, the direct usage value was estimated as 1.32 billion Yuan/year. Plant resources value was 318 million Yuan/year; animal resources value was 675 million Yuan/year; and water storage value was 325 million Yuan/year for the three parts. [Conclusion] This paper will attract more attention to the emphasis of the reasonable development of nature sources.展开更多
According to the distribution characteristics of traffic congestion in time and space, a measure index system of urban traffic congestion is set up based on the spatial and temporal distribution. Based on the analysis...According to the distribution characteristics of traffic congestion in time and space, a measure index system of urban traffic congestion is set up based on the spatial and temporal distribution. Based on the analysis of the main characteristics of traffic congestion and the generation process of traffic congestion, the measure model for urban traffic congestion is constructed by the value function. Moreover, based on the measure values of traffic congestion in urban road networks with defined different levels, a method to prevent and control traffic congestion is designed. The application results confirm that the proposed method is feasible in comprehensive measures for urban traffic congestion and they are consistent with the results of other methods. The measuring results can therefore reflect the actual situation. The comprehensive measure model is scientific and the process is simple, and it has wide application prospects and practical value.展开更多
According to basic connotation and design principles of ecocity, a comparatively integrated index system is constructed in the paper. And at the same time using hierarchy grey comprehensive evaluation method, a hierar...According to basic connotation and design principles of ecocity, a comparatively integrated index system is constructed in the paper. And at the same time using hierarchy grey comprehensive evaluation method, a hierarchy grey comprehensive evaluation model of ecocity is established, then on the basis of the model, a comprehensive evaluation support system is developed, and the theoretical guidance supplied for construction of ecocity is provided.展开更多
Using VAR-DCC-GARCH model,the literature on commodity price was extended by exploring the co-movement between Chinese nonferrous metal prices and global nonferrous metal prices represented by the nonferrous metal pric...Using VAR-DCC-GARCH model,the literature on commodity price was extended by exploring the co-movement between Chinese nonferrous metal prices and global nonferrous metal prices represented by the nonferrous metal prices from London Metal Exchange(LME).The results show that LME nonferrous metals prices still have a greater impact on Chinese nonferrous metals prices.However,the impact of Chinese nonferrous metals prices on LME nonferrous metals prices is still weak except for lead price.The co-movement of nonferrous metal prices between LME and China presents hysteretic nature,and it lasts for 7-8trading days.Furthermore,the co-movement between LME nonferrous metals prices and Chinese nonferrous metals prices has the characteristics of time-varying,and the correlation of lead prices between LME and China is the more stable than all other nonferrous metals prices.展开更多
Human pressure on mountain resources poses certain threats to their natural and man-made environment. Although there are many parameters involved, one of the driving forces behind this situation is the emphasis given ...Human pressure on mountain resources poses certain threats to their natural and man-made environment. Although there are many parameters involved, one of the driving forces behind this situation is the emphasis given so far only to the market value of mountain goods and services, ignoring the true social and environmental costs of using mountain resources. Towards this direction, the use of non-market valuation techniques could prove to be beneficial. Bearing in mind the above remarks, the paper presents an application of the Contingent Valuation Method, which aims at estimating the monetary value of a mountain settlement’s vernacular architecture, namely Metsovo. For this purpose, the survey focuses on Metsovo visitors’ willingness to pay a single annual voluntary contribution to an institution that would be founded in order to undertake all necessary actions required to preserve the town’s traditional character. The results are very promising and indicate that vernacular architecture holds a significant economic value that could justify the implementation of appropriate policies towards the protection of vernacular settlements in mountain areas.展开更多
Municipal public utilities reform is an important part of the economic system structural reform of cities. In this paper a kind of market competition mechanism for commercial municipal public enterprises is proposed; ...Municipal public utilities reform is an important part of the economic system structural reform of cities. In this paper a kind of market competition mechanism for commercial municipal public enterprises is proposed; a price competition model of municipal public enterprises with similar products is founded; its static and dynamic game analysis is offered and a comparison between them is made. The results show that,for the business type of municipal public enterprise market competition mechanism can be introduced to mobilize the enterprise activity to raise the end of efficiency; the government may control the market price through the economic measures of regulating the amount of subsidy;that enterprises enter the market and select the price simultaneously is more advantageous than entering the market one after another in general, information among the municipal enterprises is symmetrical (the equilibrium is lower); "following enterprises" gets "second mover advantage";to raise the difference of the same product will increase the profit of enterprise.展开更多
This paper reviewed the development of Strategic Environmental Assessment (SEA) in China, expounded its functions and regional characteristics, and discussed the targets of SEA in the process of urbanization,and the m...This paper reviewed the development of Strategic Environmental Assessment (SEA) in China, expounded its functions and regional characteristics, and discussed the targets of SEA in the process of urbanization,and the main assessment indicators, procedures, techniques and methodologies of SEA. It concluded that SEA could be improved by the following recommendations: incorporating SEA in decision-making process, selecting experimental units for SEA trial run, and developing strategic evaluation tools and techniques. SEA can provide appropriate and up-to-date information on the impact of human activity on environment in the process of urbanization, and develop a plan of action targeting implementation of intervention for the rehabilitation and preservation of the ecological stability of a city. Therefore, SEA can be a supporting tool for decision-making toward achieving sustainable development.展开更多
In order to better explore the function of urban forest in human habitation and settlement environment,the ecosystem functions were evaluated in terms of air purification,water conservation,soil conservation,maintenan...In order to better explore the function of urban forest in human habitation and settlement environment,the ecosystem functions were evaluated in terms of air purification,water conservation,soil conservation,maintenance of biodiversity in Meizhou by the methods of market price,shadow prices approach and opportunity cost,and the problems of the value assessment at home and abroad in urban forest ecosystem services function were simply discussed.展开更多
Wetlands play an important ecological role and provide many functions for people, yet wetlands are cur- rently decreasing and deteriorating. The ability to calculate an economic value for the loss of wetlands is becom...Wetlands play an important ecological role and provide many functions for people, yet wetlands are cur- rently decreasing and deteriorating. The ability to calculate an economic value for the loss of wetlands is becoming in- creasingly important for policy makers. In this study, remote sensing, field investigations, department visits, and other methods were used to survey wetland types, assess wetland area changes, and calculate wetland economic value. Mar- ket value loss and ecological ftmction value loss, caused by reduction of wetland area and environmental pollution were calculated using commonly accepted methods of market valuation, ecological valuation, environmental protection investment cost analysis, and outcome parameters. According to market value loss and ecological function value loss, preliminarily fund allocation for wetland and ecological compensation was calculated. This will provide an important reference for future Yellow River Delta eco-compensation studies.展开更多
Customer satisfaction is an important index to evaluate the competitiveness and efficiency of an enterprise. Every enterprise is confront with the subject of supplying with the customer satisfactory products at the lo...Customer satisfaction is an important index to evaluate the competitiveness and efficiency of an enterprise. Every enterprise is confront with the subject of supplying with the customer satisfactory products at the lowest costs and the highest manufacturing speed. Regarding the delivery days of a coach company as a design variable, this paper builds up an optimization model of customer satisfaction, and suggests an effective method to reduce costs and increase customer satisfaction based on analysis and research.展开更多
Matter-element analysis method was used to construct the comprehensive matter-element model for the evaluation of the quality of various kinds of irrigation water in Turpan City to evaluate the quality of irrigation w...Matter-element analysis method was used to construct the comprehensive matter-element model for the evaluation of the quality of various kinds of irrigation water in Turpan City to evaluate the quality of irrigation water(such as river water,spring water, Karez well water, pumped well water) in Turpan City, Xinjiang. The results showed that the quality of the irrigation water was the best in October,which was in Grade I or Grade 2; in May, the quality of some of the irrigation water became poorer to Grade II, which was easy to soil salinization; in March, the detected qualities of the water samples water from the Meiyaogou basin were all in Grade IV, which was not suitable for farmland irrigation. The comparison on the evaluation results of matter-element analysis and fuzzy evaluation method showed that the results of the 2 methods were almost consistent with each other, and showed good uniformity.展开更多
There are three primary methodologies employed to determine real estate value in the appraisal industry: the cost approach, the sales approach and the income approach. The definition of market value is defined as: ...There are three primary methodologies employed to determine real estate value in the appraisal industry: the cost approach, the sales approach and the income approach. The definition of market value is defined as: "a type of value, stated as an opinion that includes a set of assumptions concerning the market". Unfortunately, untrained and unlicensed appraisers provided opinions using primarily the sales approach or market data approach and virtually ignored the other two methodologies. The ensuing game of "Can You Top This" resulted in creating an out-of-control real estate market driven by unregulated fiduciaries as appraisers.展开更多
Based on the remote sensing images of urban land use of Chongqing City Proper in the last 30years(from 1978 to 2011),The paper focuses on the impact of urban spatial expansion on urban ecosystem service.The charactere...Based on the remote sensing images of urban land use of Chongqing City Proper in the last 30years(from 1978 to 2011),The paper focuses on the impact of urban spatial expansion on urban ecosystem service.The charactereristics of urban spatial expansion pattern are expressed by Landscape Expansion Index and Index of Fractal Dimension.Taking advantage of calculation of these two indices,changes of the ecological service values in the main urban area of Chongqing caused by the variation of urban expansion patterns are evaluated and the interrelationship is analyzed.The main conclusions and results are as follows;in Chongqing City Proper,the ecological service value decreased rapidly from 1978 to 2011,especially in the period of 2002-2011.Urban spatial expansion pattern has exerted significant impact on urban ecosystem service value.Edge-expansion pattern broke into a great deal of urban enclaves and caused the disadvantage effect of the function of urban ecological system.At the same time,negative correlation existed between the indices of fractal dimension and the ecosystem service value.展开更多
Yam, Dioscorea esculenta which is a high value commodity is a threatened species in Ghana, due to several factors including neglect on the part of science, technology, research and development. Different doses of radi...Yam, Dioscorea esculenta which is a high value commodity is a threatened species in Ghana, due to several factors including neglect on the part of science, technology, research and development. Different doses of radiation were use to improve the size and market value of D. esculenta to promote it effective use and enhance effective conservation. We observed through repeated experiments that irradiation of yam planting material at 40 Gy gave the best results producing a M1 generation with a decreased number of tubers but with an increased tuber size per vine. Some yam characteristics are valued more than others, and prices vary across species, time, and market sites. Tuber weight exhibits an increasing marginal value and price per kilogram increases above an optimum size; therefore, yam producers and dealers derive additional reward from extra-large tubers. We conclude that, to effectively access and benefit from urban markets, producers should focus on the improved size and conical shaped-tubers, which are easy to process and meet the aesthetic qualities preferred by urban consumers. The implications for research on improved variety development to reduce poverty and for crop and resource management practices are drawn.展开更多
Shale gas is a practical resource with great potential that could be economically explored and developed in the near future. It has been commercially developed in North America and other places. Featuring a vast distr...Shale gas is a practical resource with great potential that could be economically explored and developed in the near future. It has been commercially developed in North America and other places. Featuring a vast distribution, a low abundance,unfavorable reservoir conditions, ultra-low permeability and a fast production decline, shale gas is more difficult to develop than conventional natural gas, as it needs advanced drilling and completion technology to develop. During the early stage of shale gas exploration and development, the United States offered enterprises necessary incentives such as tax reductions and exemptions and subsidies to achieve sustainable shale gas development and encourage technological progresses. By comparing the state of China's shale gas development with that of the US' in terms of geological conditions, production technology,market price, tax relief, subsidy periods and amount, this paper intends to put forward related suggestions for the effective development of shale gas according to the current status of development.展开更多
The hedonic price model is widely applied to study the urban housing market because of the heterogeneity of housing products. Literature indicated that the hedonic price theory mainly includes two parts: Lancaster’s ...The hedonic price model is widely applied to study the urban housing market because of the heterogeneity of housing products. Literature indicated that the hedonic price theory mainly includes two parts: Lancaster’s partiality theory and Rosen’s characteristic market equilibrium analysis. This paper chose 18 characteristics as independent variables and set up a linear hedonic price model for Hangzhou City. The model was tested with 2473 housing samples and field survey data of 290 housing commu-nities. This research found that 14 out of 18 characteristics had significant influence on housing price. They were classified into 5 groups according to their impact degree.展开更多
One of most challenging problems from applying the Black-Scholes model to financial derivatives, is reconciling the deviation between the expected and observed values. This study derives an extension of the Black-Scho...One of most challenging problems from applying the Black-Scholes model to financial derivatives, is reconciling the deviation between the expected and observed values. This study derives an extension of the Black-Scholes model and recovers the real drift of binary call options from their market prices. For space-dependent real drift, we obtain stable linearization and an integral equation. We also find that using market prices of options with different strike prices enables us to identify the term structure of the real drift. Results demonstrate that our new approach can confirm the existence of arbitrage opportunities in a binary option transaction.展开更多
文摘This review presents a comprehensive techno-economic and life-cycle assessment of sustainable aviation fuel(SAF)production from biomass.The critical need for transitioning towards environmentally sustainable alternatives for liquid fuel and aviation industry is first discussed.Key insights encompass the evolutionary progression of biofuel production from first-generation to second-generation biofuels,with a focus on utilizing non-food sources like woody biomass for enhanced sustainability.Available data from the literature on techno-economic assessments of various SAF production pathways are analyzed including production costs,conversion efficiency,and scalability.Moreover,results of lifecycle assessments associated with different SAF production pathways are presented,providing essential insights for decision-making processes.The challenges of scaling up woody biomass-based SAF production are discussed based on the assessment results,and recommendations are proposed to steer stakeholders towards a greener and more sustainable trajectory for aviation operations.
基金The National Key Technology R&D Program of China during the11th Five-Year Plan Period(No.2006BAH02A06)the Program Project of Humanity and Social Science of Ministry of Education in China(No.06JA630012)
文摘The concept of the e-marketplace is introduced.Considering a supply chain with a single manufacturer who sells a single item in an e-marketplace,an analytical model for the use of the e-marketplace in a supply chain is provided.Assuming the market demand is stochastic and price-dependent,the conditions under which the manufacturer and the e-marketplace owner share the market in equilibrium is developed.The existence and uniqueness of the optimal selling price,quantity and transaction percentage are proved.An integrated supply chain is put forward,and then the efficiency of supply chain coordination is studied by comparing the integrated supply chain with the decentralized supply chain.To gain further insights on the theoretical models,extensive simulations are then carried out.
文摘[Obective] This study amied to evaluate the direct usage value of Liangzi Lake, like plants and animal resources and water storage value. [Method] It was measured through the market value method. The physical environment was introduced and the productivity of the lake was investigated both through the literature materials and the investigations. The market value method was clarified in this paper as well as its operation process and the application fields. [Result] Based on the introduction of the current situation in Liangzi Lake, the direct usage value was estimated as 1.32 billion Yuan/year. Plant resources value was 318 million Yuan/year; animal resources value was 675 million Yuan/year; and water storage value was 325 million Yuan/year for the three parts. [Conclusion] This paper will attract more attention to the emphasis of the reasonable development of nature sources.
基金The National Natural Science Foundation of China(No.51178157)
文摘According to the distribution characteristics of traffic congestion in time and space, a measure index system of urban traffic congestion is set up based on the spatial and temporal distribution. Based on the analysis of the main characteristics of traffic congestion and the generation process of traffic congestion, the measure model for urban traffic congestion is constructed by the value function. Moreover, based on the measure values of traffic congestion in urban road networks with defined different levels, a method to prevent and control traffic congestion is designed. The application results confirm that the proposed method is feasible in comprehensive measures for urban traffic congestion and they are consistent with the results of other methods. The measuring results can therefore reflect the actual situation. The comprehensive measure model is scientific and the process is simple, and it has wide application prospects and practical value.
文摘According to basic connotation and design principles of ecocity, a comparatively integrated index system is constructed in the paper. And at the same time using hierarchy grey comprehensive evaluation method, a hierarchy grey comprehensive evaluation model of ecocity is established, then on the basis of the model, a comprehensive evaluation support system is developed, and the theoretical guidance supplied for construction of ecocity is provided.
基金Project(71073177)supported by the National Natural Science Foundation of ChinaProject(12JJ4077)supported by the Natural Science Foundation of Hunan Province of ChinaProject(2012zzts002)supported by the Fundamental Research Funds of Central South University,China
文摘Using VAR-DCC-GARCH model,the literature on commodity price was extended by exploring the co-movement between Chinese nonferrous metal prices and global nonferrous metal prices represented by the nonferrous metal prices from London Metal Exchange(LME).The results show that LME nonferrous metals prices still have a greater impact on Chinese nonferrous metals prices.However,the impact of Chinese nonferrous metals prices on LME nonferrous metals prices is still weak except for lead price.The co-movement of nonferrous metal prices between LME and China presents hysteretic nature,and it lasts for 7-8trading days.Furthermore,the co-movement between LME nonferrous metals prices and Chinese nonferrous metals prices has the characteristics of time-varying,and the correlation of lead prices between LME and China is the more stable than all other nonferrous metals prices.
文摘Human pressure on mountain resources poses certain threats to their natural and man-made environment. Although there are many parameters involved, one of the driving forces behind this situation is the emphasis given so far only to the market value of mountain goods and services, ignoring the true social and environmental costs of using mountain resources. Towards this direction, the use of non-market valuation techniques could prove to be beneficial. Bearing in mind the above remarks, the paper presents an application of the Contingent Valuation Method, which aims at estimating the monetary value of a mountain settlement’s vernacular architecture, namely Metsovo. For this purpose, the survey focuses on Metsovo visitors’ willingness to pay a single annual voluntary contribution to an institution that would be founded in order to undertake all necessary actions required to preserve the town’s traditional character. The results are very promising and indicate that vernacular architecture holds a significant economic value that could justify the implementation of appropriate policies towards the protection of vernacular settlements in mountain areas.
文摘Municipal public utilities reform is an important part of the economic system structural reform of cities. In this paper a kind of market competition mechanism for commercial municipal public enterprises is proposed; a price competition model of municipal public enterprises with similar products is founded; its static and dynamic game analysis is offered and a comparison between them is made. The results show that,for the business type of municipal public enterprise market competition mechanism can be introduced to mobilize the enterprise activity to raise the end of efficiency; the government may control the market price through the economic measures of regulating the amount of subsidy;that enterprises enter the market and select the price simultaneously is more advantageous than entering the market one after another in general, information among the municipal enterprises is symmetrical (the equilibrium is lower); "following enterprises" gets "second mover advantage";to raise the difference of the same product will increase the profit of enterprise.
文摘This paper reviewed the development of Strategic Environmental Assessment (SEA) in China, expounded its functions and regional characteristics, and discussed the targets of SEA in the process of urbanization,and the main assessment indicators, procedures, techniques and methodologies of SEA. It concluded that SEA could be improved by the following recommendations: incorporating SEA in decision-making process, selecting experimental units for SEA trial run, and developing strategic evaluation tools and techniques. SEA can provide appropriate and up-to-date information on the impact of human activity on environment in the process of urbanization, and develop a plan of action targeting implementation of intervention for the rehabilitation and preservation of the ecological stability of a city. Therefore, SEA can be a supporting tool for decision-making toward achieving sustainable development.
基金Supported by Special Funds for Central Financial to Support the Local Colleges and Universities([2013]389)~~
文摘In order to better explore the function of urban forest in human habitation and settlement environment,the ecosystem functions were evaluated in terms of air purification,water conservation,soil conservation,maintenance of biodiversity in Meizhou by the methods of market price,shadow prices approach and opportunity cost,and the problems of the value assessment at home and abroad in urban forest ecosystem services function were simply discussed.
基金Under the auspices of Scientific and Technological Projects of Shandong Province (No. 2006GG2206019, 2007 GG30006002)National Natural Science Foundation of China (No.40901065)
文摘Wetlands play an important ecological role and provide many functions for people, yet wetlands are cur- rently decreasing and deteriorating. The ability to calculate an economic value for the loss of wetlands is becoming in- creasingly important for policy makers. In this study, remote sensing, field investigations, department visits, and other methods were used to survey wetland types, assess wetland area changes, and calculate wetland economic value. Mar- ket value loss and ecological ftmction value loss, caused by reduction of wetland area and environmental pollution were calculated using commonly accepted methods of market valuation, ecological valuation, environmental protection investment cost analysis, and outcome parameters. According to market value loss and ecological function value loss, preliminarily fund allocation for wetland and ecological compensation was calculated. This will provide an important reference for future Yellow River Delta eco-compensation studies.
文摘Customer satisfaction is an important index to evaluate the competitiveness and efficiency of an enterprise. Every enterprise is confront with the subject of supplying with the customer satisfactory products at the lowest costs and the highest manufacturing speed. Regarding the delivery days of a coach company as a design variable, this paper builds up an optimization model of customer satisfaction, and suggests an effective method to reduce costs and increase customer satisfaction based on analysis and research.
基金Supported by the National Natural Science Foundation of China(41261030)the Key Laboratory for Oasis Ecosystem,Ministry of Education(041079)~~
文摘Matter-element analysis method was used to construct the comprehensive matter-element model for the evaluation of the quality of various kinds of irrigation water in Turpan City to evaluate the quality of irrigation water(such as river water,spring water, Karez well water, pumped well water) in Turpan City, Xinjiang. The results showed that the quality of the irrigation water was the best in October,which was in Grade I or Grade 2; in May, the quality of some of the irrigation water became poorer to Grade II, which was easy to soil salinization; in March, the detected qualities of the water samples water from the Meiyaogou basin were all in Grade IV, which was not suitable for farmland irrigation. The comparison on the evaluation results of matter-element analysis and fuzzy evaluation method showed that the results of the 2 methods were almost consistent with each other, and showed good uniformity.
文摘There are three primary methodologies employed to determine real estate value in the appraisal industry: the cost approach, the sales approach and the income approach. The definition of market value is defined as: "a type of value, stated as an opinion that includes a set of assumptions concerning the market". Unfortunately, untrained and unlicensed appraisers provided opinions using primarily the sales approach or market data approach and virtually ignored the other two methodologies. The ensuing game of "Can You Top This" resulted in creating an out-of-control real estate market driven by unregulated fiduciaries as appraisers.
基金Supported by the Key Technologies R&D Program(No.2012 BAJ23B05)the National Natural Science Foundation of China(No.40701179)
文摘Based on the remote sensing images of urban land use of Chongqing City Proper in the last 30years(from 1978 to 2011),The paper focuses on the impact of urban spatial expansion on urban ecosystem service.The charactereristics of urban spatial expansion pattern are expressed by Landscape Expansion Index and Index of Fractal Dimension.Taking advantage of calculation of these two indices,changes of the ecological service values in the main urban area of Chongqing caused by the variation of urban expansion patterns are evaluated and the interrelationship is analyzed.The main conclusions and results are as follows;in Chongqing City Proper,the ecological service value decreased rapidly from 1978 to 2011,especially in the period of 2002-2011.Urban spatial expansion pattern has exerted significant impact on urban ecosystem service value.Edge-expansion pattern broke into a great deal of urban enclaves and caused the disadvantage effect of the function of urban ecological system.At the same time,negative correlation existed between the indices of fractal dimension and the ecosystem service value.
文摘Yam, Dioscorea esculenta which is a high value commodity is a threatened species in Ghana, due to several factors including neglect on the part of science, technology, research and development. Different doses of radiation were use to improve the size and market value of D. esculenta to promote it effective use and enhance effective conservation. We observed through repeated experiments that irradiation of yam planting material at 40 Gy gave the best results producing a M1 generation with a decreased number of tubers but with an increased tuber size per vine. Some yam characteristics are valued more than others, and prices vary across species, time, and market sites. Tuber weight exhibits an increasing marginal value and price per kilogram increases above an optimum size; therefore, yam producers and dealers derive additional reward from extra-large tubers. We conclude that, to effectively access and benefit from urban markets, producers should focus on the improved size and conical shaped-tubers, which are easy to process and meet the aesthetic qualities preferred by urban consumers. The implications for research on improved variety development to reduce poverty and for crop and resource management practices are drawn.
文摘Shale gas is a practical resource with great potential that could be economically explored and developed in the near future. It has been commercially developed in North America and other places. Featuring a vast distribution, a low abundance,unfavorable reservoir conditions, ultra-low permeability and a fast production decline, shale gas is more difficult to develop than conventional natural gas, as it needs advanced drilling and completion technology to develop. During the early stage of shale gas exploration and development, the United States offered enterprises necessary incentives such as tax reductions and exemptions and subsidies to achieve sustainable shale gas development and encourage technological progresses. By comparing the state of China's shale gas development with that of the US' in terms of geological conditions, production technology,market price, tax relief, subsidy periods and amount, this paper intends to put forward related suggestions for the effective development of shale gas according to the current status of development.
基金Project supported by the National Social Science Foundation of China (No. 05CJY017), the Philosophy and Social Science Founda-tion of Zhejiang Province, China (No. N04GL06), and ShuguangProject (2004) of Zhejiang University, China
文摘The hedonic price model is widely applied to study the urban housing market because of the heterogeneity of housing products. Literature indicated that the hedonic price theory mainly includes two parts: Lancaster’s partiality theory and Rosen’s characteristic market equilibrium analysis. This paper chose 18 characteristics as independent variables and set up a linear hedonic price model for Hangzhou City. The model was tested with 2473 housing samples and field survey data of 290 housing commu-nities. This research found that 14 out of 18 characteristics had significant influence on housing price. They were classified into 5 groups according to their impact degree.
文摘One of most challenging problems from applying the Black-Scholes model to financial derivatives, is reconciling the deviation between the expected and observed values. This study derives an extension of the Black-Scholes model and recovers the real drift of binary call options from their market prices. For space-dependent real drift, we obtain stable linearization and an integral equation. We also find that using market prices of options with different strike prices enables us to identify the term structure of the real drift. Results demonstrate that our new approach can confirm the existence of arbitrage opportunities in a binary option transaction.