Potential evapotranspiration(ETo) is important to hydrological cycling and the global energy balance.Based on a modified FAO56-Penman-Monteith model,ETo was simulated for 603 meteorological stations across China in th...Potential evapotranspiration(ETo) is important to hydrological cycling and the global energy balance.Based on a modified FAO56-Penman-Monteith model,ETo was simulated for 603 meteorological stations across China in the period 1971-2008.Spatial distribution and temporal change of ETo were characterized,and the determining factors in ETo were revealed by sensitivity analysis.Results show obvious regional differences in annual average ETo and its determining factor.In general,annual average ETo decreased in the period 1971-2008,but increased since the 1990s.Wind speed and sunshine duration were determining factors in the annual ETo trend,with smaller contributions from relative humidity and temperature.Declining wind speed was the determining factor in decreasing annual ETo in northern temperate regions and the Tibetan Plateau.The spatial extent of wind speed influence contracted to northwest China in summer,and expanded to the whole country in autumn.Decreasing sunshine duration was the determining factor in decreasing annual ETo in subtropical and tropical regions,especially in summer,with a larger spatial influence mainly to the southeast of the farming-pastoral region.ETo change has distinct impacts on earth surface ecosystems and environment depending on different determining factors.展开更多
The thermodynamic systems and dynamic model suitable for determining the nonlinear chemical fingerprints of samples were analyzed.The results indicated that the damp nonlinear chemical reactions in close systems away ...The thermodynamic systems and dynamic model suitable for determining the nonlinear chemical fingerprints of samples were analyzed.The results indicated that the damp nonlinear chemical reactions in close systems away from the equilibrium and open systems without the complementarity of the dissipation substances have important significance for the throng characterization and whole content analysis of chemical components in samples.Various factors influencing on nonlinear chemical fingerprint,such as reactant species and their concentrations,electrode types,temperature,stir rate,the sort,dosage and granularity of the sample,etc.were amply researched by a nonlinear chemistry reaction,namely,damp B-Z oscillation which used acetone and glucose as the main dissipative substances.In addition,the quantitative information on the whole of chemical components in samples and the traits and applications of the fingerprint were investigated.The method and its important conditions for determining nonlinear chemistry fingerprint used in distinguishing and evaluating complex samples were successfully put forward.展开更多
Acute liver failure(ALF)is a medical emergency due to massive hepatocyte loss.In such a harsh condition,maintaining transcriptional regulation in the remaining hepatocytes while activating similar transcription factor...Acute liver failure(ALF)is a medical emergency due to massive hepatocyte loss.In such a harsh condition,maintaining transcriptional regulation in the remaining hepatocytes while activating similar transcription factor networks in liver progenitor cells(LPCs)to ensure essential liver functions are two critical processes to rescue patients from liver failure and death.In this review,we discuss the formation and functions of transcription networks in ALF and liver development.We focus on a hierarchical network of transcription factors that responds to different pathophysiological circumstances:(1)Under normal circumstances,pioneer factor forkhead box protein A2(FOXA2)coordinates several constitutive hepatic transcription factors,such as hepatic nuclear factor 4 alpha(HNF4a)and CCAAT-enhancer binding protein a(C/EBPa),which ensure normal liver function;(2)When the expression of both HNF4a and C/EBPa in hepatocytes are disrupted by severe inflammation,retinoic acid receptor(RAR)is the alternative transcription factor that compensates for their absence;(3)When massive hepatic necrosis occurs,a similar transcription network including FOXA2 and HNF4a,is activated as a“rescue network”in LPCs to maintain vital liver functions when hepatocytes fail,and thus ensures survival.Expression of these master transcription factors in hepatocytes and LPCs is tightly regulated by hormone signals and inflammation.The performance of this hierarchical transcription network,in particularly the“rescue network”described above,significantly affects the clinical outcome of ALF.展开更多
Evaluating actual crop evapotranspiration(ET) variations and their determining factors under changing climates is crucial for agricultural irrigation management and crop productivity improvement in nonhumid regions.Th...Evaluating actual crop evapotranspiration(ET) variations and their determining factors under changing climates is crucial for agricultural irrigation management and crop productivity improvement in nonhumid regions.This study analyzed the spatiotemporal characteristics and detected the determining factors of ETfor winter wheat and summer maize rotation system from 2000 to 2017 in the North China Plain(NCP),by combining the FAO-56 dual crop coefficient approach with remotely sensed vegetation indices(VIs).The results indicated that daily air temperature increased in varying degrees while wind speed and sunshine hours decreased slightly during the growing season of winter wheat and summer maize over the study period.The trends of relative humidity and effective precipitation varied in crop growing seasons.Based on the validated relationship of dual crop coefficients and VIs,the estimated multi-year average ETof winter wheat(370.29±31.28 mm) was much higher than summer maize(281.85±20.14 mm),and the rotation cycle was 652.43±27.67 mm.Annual ETof winter wheat and the rotation cycle increased by 2.96 mm aand 1,77 mm a,respectively.However,the ETof summer maize decreased with distinct spatial variation.Spatially,winter wheat ETincreased significantly in the northeast NCP,covering the Beijing-Tianiin-Hebei areas.Meanwhile,significant increases in summer maize ETwere detected in the southwest NCP.The sensitivity and contribution analysis showed that ETof winter wheat and summer maize was positively sensitive to temperature,wind speed,and sunshine hours while negatively to relative humidity.Moreover,wind speed and sunshine hours contributed most to changes in ET(around 20%-40%).展开更多
基金supported by the National Natural Science Foundation of China (40701010 and 40771016)
文摘Potential evapotranspiration(ETo) is important to hydrological cycling and the global energy balance.Based on a modified FAO56-Penman-Monteith model,ETo was simulated for 603 meteorological stations across China in the period 1971-2008.Spatial distribution and temporal change of ETo were characterized,and the determining factors in ETo were revealed by sensitivity analysis.Results show obvious regional differences in annual average ETo and its determining factor.In general,annual average ETo decreased in the period 1971-2008,but increased since the 1990s.Wind speed and sunshine duration were determining factors in the annual ETo trend,with smaller contributions from relative humidity and temperature.Declining wind speed was the determining factor in decreasing annual ETo in northern temperate regions and the Tibetan Plateau.The spatial extent of wind speed influence contracted to northwest China in summer,and expanded to the whole country in autumn.Decreasing sunshine duration was the determining factor in decreasing annual ETo in subtropical and tropical regions,especially in summer,with a larger spatial influence mainly to the southeast of the farming-pastoral region.ETo change has distinct impacts on earth surface ecosystems and environment depending on different determining factors.
基金supported by the National Key Technologies R & DProgram (2009GJD20033)the International Scientific and Technological Cooperation Project (2007DFA40680) from the Ministry of Scienceand Technology of China
文摘The thermodynamic systems and dynamic model suitable for determining the nonlinear chemical fingerprints of samples were analyzed.The results indicated that the damp nonlinear chemical reactions in close systems away from the equilibrium and open systems without the complementarity of the dissipation substances have important significance for the throng characterization and whole content analysis of chemical components in samples.Various factors influencing on nonlinear chemical fingerprint,such as reactant species and their concentrations,electrode types,temperature,stir rate,the sort,dosage and granularity of the sample,etc.were amply researched by a nonlinear chemistry reaction,namely,damp B-Z oscillation which used acetone and glucose as the main dissipative substances.In addition,the quantitative information on the whole of chemical components in samples and the traits and applications of the fingerprint were investigated.The method and its important conditions for determining nonlinear chemistry fingerprint used in distinguishing and evaluating complex samples were successfully put forward.
基金supported by the Deutsche For-schungsge meinschaft WE 5009/9e1,Chinese-German Cooperation Group projects GZ 1517(H.-L.Weng)BMBF through HiChol 01GM1904A(R.Liebe).R.Feng is supported by the Chinese Scholarship Council(Grant No.201706230256).
文摘Acute liver failure(ALF)is a medical emergency due to massive hepatocyte loss.In such a harsh condition,maintaining transcriptional regulation in the remaining hepatocytes while activating similar transcription factor networks in liver progenitor cells(LPCs)to ensure essential liver functions are two critical processes to rescue patients from liver failure and death.In this review,we discuss the formation and functions of transcription networks in ALF and liver development.We focus on a hierarchical network of transcription factors that responds to different pathophysiological circumstances:(1)Under normal circumstances,pioneer factor forkhead box protein A2(FOXA2)coordinates several constitutive hepatic transcription factors,such as hepatic nuclear factor 4 alpha(HNF4a)and CCAAT-enhancer binding protein a(C/EBPa),which ensure normal liver function;(2)When the expression of both HNF4a and C/EBPa in hepatocytes are disrupted by severe inflammation,retinoic acid receptor(RAR)is the alternative transcription factor that compensates for their absence;(3)When massive hepatic necrosis occurs,a similar transcription network including FOXA2 and HNF4a,is activated as a“rescue network”in LPCs to maintain vital liver functions when hepatocytes fail,and thus ensures survival.Expression of these master transcription factors in hepatocytes and LPCs is tightly regulated by hormone signals and inflammation.The performance of this hierarchical transcription network,in particularly the“rescue network”described above,significantly affects the clinical outcome of ALF.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA28060200)the National Science Fund for Excellent Young Scholars (42122003)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA20040301)the Youth Innovation Promotion Association,CAS (Y202016)。
文摘Evaluating actual crop evapotranspiration(ET) variations and their determining factors under changing climates is crucial for agricultural irrigation management and crop productivity improvement in nonhumid regions.This study analyzed the spatiotemporal characteristics and detected the determining factors of ETfor winter wheat and summer maize rotation system from 2000 to 2017 in the North China Plain(NCP),by combining the FAO-56 dual crop coefficient approach with remotely sensed vegetation indices(VIs).The results indicated that daily air temperature increased in varying degrees while wind speed and sunshine hours decreased slightly during the growing season of winter wheat and summer maize over the study period.The trends of relative humidity and effective precipitation varied in crop growing seasons.Based on the validated relationship of dual crop coefficients and VIs,the estimated multi-year average ETof winter wheat(370.29±31.28 mm) was much higher than summer maize(281.85±20.14 mm),and the rotation cycle was 652.43±27.67 mm.Annual ETof winter wheat and the rotation cycle increased by 2.96 mm aand 1,77 mm a,respectively.However,the ETof summer maize decreased with distinct spatial variation.Spatially,winter wheat ETincreased significantly in the northeast NCP,covering the Beijing-Tianiin-Hebei areas.Meanwhile,significant increases in summer maize ETwere detected in the southwest NCP.The sensitivity and contribution analysis showed that ETof winter wheat and summer maize was positively sensitive to temperature,wind speed,and sunshine hours while negatively to relative humidity.Moreover,wind speed and sunshine hours contributed most to changes in ET(around 20%-40%).
