Anthropogenic emission of atmospheric carbon dioxide (CO2) has led to a rapid increase in atmospheric CO2 concentra- tion. Increasing atmospheric CO2 can reduce seawater pH and carbonate ions, which may adversely affe...Anthropogenic emission of atmospheric carbon dioxide (CO2) has led to a rapid increase in atmospheric CO2 concentra- tion. Increasing atmospheric CO2 can reduce seawater pH and carbonate ions, which may adversely affect the survival of the larvae of calcareous animals. Cyclina sinensis is a commercially and ecologically important species in several Asian countries. Living in coast shallow waters, this species has experienced the coastal environmental changes frequently throughout its life cycle. In this study, we simulated possible future seawater pH values including 8.2, 7.8 and 7.4 and examined the effects of ocean acidification on the early development of C. sinensis. Clam embryos were incubated for 48 h (2 d) in control and high-CO2 seawater to compare embryo- genesis, larval growth and swimming behavior. Fertilization rate was quite sensitive to pH, and moderate acidification could induce a significant decrease in fertilization rate. However, only extreme acidification could bring significant negative effect to hatching rate, body size, and average path velocity of trochophora. Moreover, with seawater acidification, C. sinensis needs much more time to reach the same developmental stage, which increases the risk of larva survival. Together with recent studies demonstrating negative impacts of high CO2 on fertilization and larva swimming behavior, the results imply a future decrease of C. sinensis populations in oceans if its acclimation to the predicted environmental alteration does not occur.展开更多
With the rapid economic development during the last 30 years in China, more and more disparities have emerged among different regions. It has been one of the hot topics in the fields of physical geography and economic...With the rapid economic development during the last 30 years in China, more and more disparities have emerged among different regions. It has been one of the hot topics in the fields of physical geography and economic geography, and also has been the task for Chinese government to handle. Nevertheless, to quantitatively assess the impacts of physio-geographical patterns （PGP） on the regional development disparity has been ignored for a long time. In this paper, a quantitative method was adopted to assess the marginal effects of the PGP on spatio-temporal disparity using the partial determination coefficients. The paper described the construction of the evaluation model step by step following its key scientific thinking. Total GDP, per capita GDP, primary industrial output value and secondary industrial output value were employed in this study as the indicators to reflect the impacts of PGP on the regional development disparity. Based on the evaluation methods built by researchers, this study firstly analyzed the temporal impacts of the PGP on spatio-temporal disparity of the regional development in China during the past 50 years, and then explained the spatial differences at each development stage. The results show that the spatio-temporal disparity in China is highly related to the PGP, and that the marginal contribution rate could be employed as an effective way to quantitatively assess the impact of the PGP on spatio-temporal disparity of the regional development.展开更多
本文探讨了利率市场化影响宏观经济的存贷利差渠道。本文首先利用阿尔钦-张五常-巴泽尔所构建的价格管制理论,分析了利率市场化如何降低实际的存贷利差。在此基础上,本文将Hall(2011)的存贷利差模型与Kiyotaki and Moore(1997)所构建的...本文探讨了利率市场化影响宏观经济的存贷利差渠道。本文首先利用阿尔钦-张五常-巴泽尔所构建的价格管制理论,分析了利率市场化如何降低实际的存贷利差。在此基础上,本文将Hall(2011)的存贷利差模型与Kiyotaki and Moore(1997)所构建的信用约束模型结合起来,构建了一个分析利率市场化宏观经济效应的信用约束模型,并通过冲击模拟分析,具体考察了存贷利差变化对模型稳定状态的影响,以及在新的稳定状态下主要变量对真实冲击和金融冲击的反应。研究发现,存贷利差降低会使得经济中主要变量的稳定状态增加(经济增长),且贷款价值比例越高,这种变化越敏感;在新的稳定状态下,存贷利差越低,则模型主要变量对同样太小的真实外生冲击反应越小,即经济变得更加平稳、波动幅度降低。展开更多
基金supported by the Central Public-interest Scientific Institution Basal Research Fund (Nos. 2016HYZD0601 and 2018HYXKQ01-10)the Fund of Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, P. R. Chinathe National Modern Agricultural Industry Technology System Construction Project (No. CARS-49)
文摘Anthropogenic emission of atmospheric carbon dioxide (CO2) has led to a rapid increase in atmospheric CO2 concentra- tion. Increasing atmospheric CO2 can reduce seawater pH and carbonate ions, which may adversely affect the survival of the larvae of calcareous animals. Cyclina sinensis is a commercially and ecologically important species in several Asian countries. Living in coast shallow waters, this species has experienced the coastal environmental changes frequently throughout its life cycle. In this study, we simulated possible future seawater pH values including 8.2, 7.8 and 7.4 and examined the effects of ocean acidification on the early development of C. sinensis. Clam embryos were incubated for 48 h (2 d) in control and high-CO2 seawater to compare embryo- genesis, larval growth and swimming behavior. Fertilization rate was quite sensitive to pH, and moderate acidification could induce a significant decrease in fertilization rate. However, only extreme acidification could bring significant negative effect to hatching rate, body size, and average path velocity of trochophora. Moreover, with seawater acidification, C. sinensis needs much more time to reach the same developmental stage, which increases the risk of larva survival. Together with recent studies demonstrating negative impacts of high CO2 on fertilization and larva swimming behavior, the results imply a future decrease of C. sinensis populations in oceans if its acclimation to the predicted environmental alteration does not occur.
基金National Natural Science Foundation of China, No.40131010
文摘With the rapid economic development during the last 30 years in China, more and more disparities have emerged among different regions. It has been one of the hot topics in the fields of physical geography and economic geography, and also has been the task for Chinese government to handle. Nevertheless, to quantitatively assess the impacts of physio-geographical patterns （PGP） on the regional development disparity has been ignored for a long time. In this paper, a quantitative method was adopted to assess the marginal effects of the PGP on spatio-temporal disparity using the partial determination coefficients. The paper described the construction of the evaluation model step by step following its key scientific thinking. Total GDP, per capita GDP, primary industrial output value and secondary industrial output value were employed in this study as the indicators to reflect the impacts of PGP on the regional development disparity. Based on the evaluation methods built by researchers, this study firstly analyzed the temporal impacts of the PGP on spatio-temporal disparity of the regional development in China during the past 50 years, and then explained the spatial differences at each development stage. The results show that the spatio-temporal disparity in China is highly related to the PGP, and that the marginal contribution rate could be employed as an effective way to quantitatively assess the impact of the PGP on spatio-temporal disparity of the regional development.
文摘本文探讨了利率市场化影响宏观经济的存贷利差渠道。本文首先利用阿尔钦-张五常-巴泽尔所构建的价格管制理论,分析了利率市场化如何降低实际的存贷利差。在此基础上,本文将Hall(2011)的存贷利差模型与Kiyotaki and Moore(1997)所构建的信用约束模型结合起来,构建了一个分析利率市场化宏观经济效应的信用约束模型,并通过冲击模拟分析,具体考察了存贷利差变化对模型稳定状态的影响,以及在新的稳定状态下主要变量对真实冲击和金融冲击的反应。研究发现,存贷利差降低会使得经济中主要变量的稳定状态增加(经济增长),且贷款价值比例越高,这种变化越敏感;在新的稳定状态下,存贷利差越低,则模型主要变量对同样太小的真实外生冲击反应越小,即经济变得更加平稳、波动幅度降低。
