China ＇s sectoral trade composition, product quality mix, and the import content of processing exports have all changed substantially during the past decade. This has rendered trade elasticities estimated using aggre...China ＇s sectoral trade composition, product quality mix, and the import content of processing exports have all changed substantially during the past decade. This has rendered trade elasticities estimated using aggregate data highly unstable, with more recent data pointing to significantly higher demand and price elasticities. Sectoral differences in these parameters are also very wide. All this suggests greater caution should be exercised when using historical data to simulate the response of China＇s economy to external shocks and exchange rate changes. Analyses based on models with estimated coefficients largely representative of China in the 1980s and 1990s are likely to turn out to be wrong, perhaps even dramatically.展开更多
To clarify the changes in plant photosynthesis and mechanisms underlying those responses to gradually increasing soil drought stress and reveal quantitative relationships between photosynthesis and soil moisture,soil ...To clarify the changes in plant photosynthesis and mechanisms underlying those responses to gradually increasing soil drought stress and reveal quantitative relationships between photosynthesis and soil moisture,soil water conditions were controlled in greenhouse pot experiments using 2-year-old seedlings of Forsythia suspensa（Thunb.） Vahl. Photosynthetic gas exchange and chlorophyll fluorescence variables were measured and analyzed under 13 gradients of soil water content. Net photosynthetic rate（PN）, stomatal conductance（gs）, and water-use efficiency（WUE） in the seedlings exhibited a clear threshold response to the relative soil water content（RSWC）. The highest PNand WUEoccurred at RSWCof51.84 and 64.10%, respectively. Both PNand WUEwere higher than the average levels at 39.79% B RSWCB 73.04%. When RSWCdecreased from 51.84 to 37.52%,PN, gs, and the intercellular CO2 concentration（Ci）markedly decreased with increasing drought stress; the corresponding stomatal limitation（Ls） substantially increased, and nonphotochemical quenching（NPQ） also tended to increase, indicating that within this range of soil water content, excessive excitation energy was dispersed from photosystem II（PSII） in the form of heat, and the reduction in PNwas primarily due to stomatal limitation.While RSWCdecreased below 37.52%, there were significant decreases in the maximal quantum yield of PSII photochemistry（Fv/Fm） and the effective quantum yield of PSII photochemistry（UPSII）, photochemical quenching（qP）, and NPQ; in contrast, minimal fluorescence yield of the dark-adapted state（F0） increased markedly. Thus,the major limiting factor for the PNreduction changed to a nonstomatal limitation due to PSII damage. Therefore, an RSWCof 37.52% is the maximum allowable water deficit for the normal growth of seedlings of F. suspensa, and a water content lower than this level should be avoided in field soil water management. Water contents should be maintained in the range of 39.79% B RSWCB 73.04% t展开更多
A pegged exchange rate regime has been pivotal to China＇s export-led development strategy. However, its huge trade surpluses and massive build up of international reserves have been matched by large deficits for majo...A pegged exchange rate regime has been pivotal to China＇s export-led development strategy. However, its huge trade surpluses and massive build up of international reserves have been matched by large deficits for major trading partners, creating acute policy concerns abroad, especially in the USA. This paper provides a straighOeorward conceptual framework for interpreting the effect of China＇s exchange rate policy on its own trade balance and that of trading partners in the context of discrepant economic growth rates. It shows how pegging the exchange rate when output is outstripping expenditure induces China＇ s trade surpluses and counterpart deficits for its trading partners. An important corollary is that given its strictly regulated capital account, China＇s persistently large surpluses imply a significantly undervalued renminbi, which should gradually become more flexible.展开更多
文摘China ＇s sectoral trade composition, product quality mix, and the import content of processing exports have all changed substantially during the past decade. This has rendered trade elasticities estimated using aggregate data highly unstable, with more recent data pointing to significantly higher demand and price elasticities. Sectoral differences in these parameters are also very wide. All this suggests greater caution should be exercised when using historical data to simulate the response of China＇s economy to external shocks and exchange rate changes. Analyses based on models with estimated coefficients largely representative of China in the 1980s and 1990s are likely to turn out to be wrong, perhaps even dramatically.
基金supported by the National Natural Science Foundation of China(Nos.41621061,31500511)the Natural Science Foundation of Shandong Province of China(No.ZR2015CL044)
文摘To clarify the changes in plant photosynthesis and mechanisms underlying those responses to gradually increasing soil drought stress and reveal quantitative relationships between photosynthesis and soil moisture,soil water conditions were controlled in greenhouse pot experiments using 2-year-old seedlings of Forsythia suspensa（Thunb.） Vahl. Photosynthetic gas exchange and chlorophyll fluorescence variables were measured and analyzed under 13 gradients of soil water content. Net photosynthetic rate（PN）, stomatal conductance（gs）, and water-use efficiency（WUE） in the seedlings exhibited a clear threshold response to the relative soil water content（RSWC）. The highest PNand WUEoccurred at RSWCof51.84 and 64.10%, respectively. Both PNand WUEwere higher than the average levels at 39.79% B RSWCB 73.04%. When RSWCdecreased from 51.84 to 37.52%,PN, gs, and the intercellular CO2 concentration（Ci）markedly decreased with increasing drought stress; the corresponding stomatal limitation（Ls） substantially increased, and nonphotochemical quenching（NPQ） also tended to increase, indicating that within this range of soil water content, excessive excitation energy was dispersed from photosystem II（PSII） in the form of heat, and the reduction in PNwas primarily due to stomatal limitation.While RSWCdecreased below 37.52%, there were significant decreases in the maximal quantum yield of PSII photochemistry（Fv/Fm） and the effective quantum yield of PSII photochemistry（UPSII）, photochemical quenching（qP）, and NPQ; in contrast, minimal fluorescence yield of the dark-adapted state（F0） increased markedly. Thus,the major limiting factor for the PNreduction changed to a nonstomatal limitation due to PSII damage. Therefore, an RSWCof 37.52% is the maximum allowable water deficit for the normal growth of seedlings of F. suspensa, and a water content lower than this level should be avoided in field soil water management. Water contents should be maintained in the range of 39.79% B RSWCB 73.04% t
文摘A pegged exchange rate regime has been pivotal to China＇s export-led development strategy. However, its huge trade surpluses and massive build up of international reserves have been matched by large deficits for major trading partners, creating acute policy concerns abroad, especially in the USA. This paper provides a straighOeorward conceptual framework for interpreting the effect of China＇s exchange rate policy on its own trade balance and that of trading partners in the context of discrepant economic growth rates. It shows how pegging the exchange rate when output is outstripping expenditure induces China＇ s trade surpluses and counterpart deficits for its trading partners. An important corollary is that given its strictly regulated capital account, China＇s persistently large surpluses imply a significantly undervalued renminbi, which should gradually become more flexible.
