As an important means regulating the relationship between human and natural ecosystem,ecological restoration program plays a key role in restoring ecosystem functions.The Grain-for-Green Program(GFGP,One of the world...As an important means regulating the relationship between human and natural ecosystem,ecological restoration program plays a key role in restoring ecosystem functions.The Grain-for-Green Program(GFGP,One of the world’s most ambitious ecosystem conservation set-aside programs aims to transfer farmland on steep slopes to forestland or grassland to increase vegetation coverage)has been widely implemented from 1999 to 2015 and exerted significant influence on land use and ecosystem services(ESs).In this study,three ecological models(In VEST,RUSLE,and CASA)were used to accurately calculate the three key types of ESs,water yield(WY),soil conservation(SC),and net primary production(NPP)in Karst area of southwestern China from 1982 to 2015.The impact of GFGP on ESs and trade-offs was analyzed.It provides practical guidance in carrying out ecological regulation in Karst area of China under global climate change.Results showed that ESs and trade-offs had changed dramatically driven by GFGP.In detail,temporally,SC and NPP exhibited an increasing trend,while WY exhibited a decreasing trend.Spatially,SC basically decreased from west to east;NPP basically increased from north to south;WY basically increased from west to east;NPP and SC,SC and WY developed in the direction of trade-offs driven by the GFGP,while NPP and WY developed in the direction of synergy.Therefore,future ecosystem management and restoration policy-making should consider trade-offs of ESs so as to achieve sustainable provision of ESs.展开更多
粮食生产服务与土壤保持服务的供给矛盾是制约怒江流域可持续发展的一大阻碍。以流域中心的施甸县为例,使用均方根偏差(Root Mean Square Error, RMSE)方法评估了2000—2020年粮食生产和土壤保持服务权衡强度的空间特征变化。然后将202...粮食生产服务与土壤保持服务的供给矛盾是制约怒江流域可持续发展的一大阻碍。以流域中心的施甸县为例,使用均方根偏差(Root Mean Square Error, RMSE)方法评估了2000—2020年粮食生产和土壤保持服务权衡强度的空间特征变化。然后将2020年作为基准年,以坡耕地生态恢复作为决策变量,使用多目标线性规划提取了高生态恢复优先的区域,进而识别了权衡强度与恢复潜力的空间分布异同。研究结果表明,(1)两项生态系统服务权衡的空间分异明显,研究期间权衡强度呈增加趋势,RMSE平均值由2000年的0.466增加至2020年的0.499;高权衡强度区域主要集中在研究区的低海拔坝区,而低权衡强度区域分布零散,且高/低权衡强度区域在空间上都表现出聚集的特征。(2)根据线性规划绘制的效率前沿曲线,在土壤保持服务收益达到13.35×10^(6)t hm^(-2)a^(-1)时需要转出3388.51hm^(2)坡耕地,同时粮食生产服务损失达9.59×10^(6)kg,而继续提升会显著增加成本。(3)各权衡强度等级坡耕地的生态恢复潜力为:中权衡>低权衡>高权衡,其中权衡强度在0.4—0.5区间的坡耕地最适宜进行生态恢复。这一研究结果可以为山地区域坡耕地利用模式提供参考,推进可持续发展目标的实现。展开更多
Over the years,many scholars have conducted a wealth of empirical research on the effectiveness of technical indicator analysis in the financial market,and the conclusions are obviously different.Among them,two progra...Over the years,many scholars have conducted a wealth of empirical research on the effectiveness of technical indicator analysis in the financial market,and the conclusions are obviously different.Among them,two program trading models based on RSI and CCI indicators achieve an annual return rate of more than 180%in the empirical research of palm oil futures program trading,but the amount of data used in this study is too small,and the transaction cost is not considered.As the actual trading process has the characteristics that investors pay more attention to the sustainability of the model's profitability,and that investors’trading varieties are diverse and with high transaction cost,this paper further verifies the sustainability and general applicability of these two models:using the closing price of 1-day and 30-minute K-line of 18 kinds of commodity futures in recent 10 years to investigate the changes of annual return rate,maximum withdrawal ratio etc.under different transaction costs and K-line cycles.The results show that the model’s profitability is time-varying,and the transaction cost has a greater influence on the rate of return of 30-minute K-lines than that of 1-day K-lines.展开更多
基金Under the auspices of National Key Technology Research and Development Project of China(No.2018YFC0507301-02)Chinese Academy of Sciences,Strategic Pilot Science and Technology Project(Class A)(No.XDA2002040201)Shaanxi Province Natural Science Basic Research Project(No.2018JM4016)
文摘As an important means regulating the relationship between human and natural ecosystem,ecological restoration program plays a key role in restoring ecosystem functions.The Grain-for-Green Program(GFGP,One of the world’s most ambitious ecosystem conservation set-aside programs aims to transfer farmland on steep slopes to forestland or grassland to increase vegetation coverage)has been widely implemented from 1999 to 2015 and exerted significant influence on land use and ecosystem services(ESs).In this study,three ecological models(In VEST,RUSLE,and CASA)were used to accurately calculate the three key types of ESs,water yield(WY),soil conservation(SC),and net primary production(NPP)in Karst area of southwestern China from 1982 to 2015.The impact of GFGP on ESs and trade-offs was analyzed.It provides practical guidance in carrying out ecological regulation in Karst area of China under global climate change.Results showed that ESs and trade-offs had changed dramatically driven by GFGP.In detail,temporally,SC and NPP exhibited an increasing trend,while WY exhibited a decreasing trend.Spatially,SC basically decreased from west to east;NPP basically increased from north to south;WY basically increased from west to east;NPP and SC,SC and WY developed in the direction of trade-offs driven by the GFGP,while NPP and WY developed in the direction of synergy.Therefore,future ecosystem management and restoration policy-making should consider trade-offs of ESs so as to achieve sustainable provision of ESs.
基金This research is partially supported by:(1)Key R&D Plan of Guangxi(Project No.:2017AB17011)Basic Competency Promotion Project for College and University Young Teachers of Guangxi(Project No.:2017KY0600)Academic Research Project of Guangxi University of Finance and Economics(Project No.:2016YBKT14).
文摘Over the years,many scholars have conducted a wealth of empirical research on the effectiveness of technical indicator analysis in the financial market,and the conclusions are obviously different.Among them,two program trading models based on RSI and CCI indicators achieve an annual return rate of more than 180%in the empirical research of palm oil futures program trading,but the amount of data used in this study is too small,and the transaction cost is not considered.As the actual trading process has the characteristics that investors pay more attention to the sustainability of the model's profitability,and that investors’trading varieties are diverse and with high transaction cost,this paper further verifies the sustainability and general applicability of these two models:using the closing price of 1-day and 30-minute K-line of 18 kinds of commodity futures in recent 10 years to investigate the changes of annual return rate,maximum withdrawal ratio etc.under different transaction costs and K-line cycles.The results show that the model’s profitability is time-varying,and the transaction cost has a greater influence on the rate of return of 30-minute K-lines than that of 1-day K-lines.
