Green's functions for Biot's dynamic equation in the frequency domain can be a highly useful tool for the investigation of dynamic responses of a saturated porous medium. Its applications are found in soil dyn...Green's functions for Biot's dynamic equation in the frequency domain can be a highly useful tool for the investigation of dynamic responses of a saturated porous medium. Its applications are found in soil dynamics, seismology, earthquake engineering,rock mechanics, geophysics, and acoustics. However, the mathematical work for deriving it can be daunting. Green's functions have been presented utilizing an analogy between the dynamic thermoelasticity and the dynamic poroelasticity in the frequency domain using the u-p formulation. In this work, a special term "decoupling coefficient" for the decomposition of the fast and slow dilatational waves is proposed and expressed to present a new methodology for deriving the poroelastodynamic Green's functions. The correctness of the solution is demonstrated by numerically comparing the current solution with Cheng's previous solution. The separation of the two waves in the present methodology allows the more accurate evaluation of Green's functions, particularly the solution of the slow dilatational wave. This can be advantageous for the numerical implementation of the boundary element method(BEM) and other applications.展开更多
Background:Efficient and selective utilization of metabolic substrates is one of the key strategies in high-altitude animals to cope with hypoxia and hypothermia.Previous findings have shown that the energy substrate ...Background:Efficient and selective utilization of metabolic substrates is one of the key strategies in high-altitude animals to cope with hypoxia and hypothermia.Previous findings have shown that the energy substrate utilization of highland animals varies with evolutionary history and phylogeny.The heart is a proxy for the cardiopulmonary system,and the metabolic substrate utilization in the myocardium is also under the strong selective pressure of chronically hypoxic and hypothermic environments.However,little information is available on the physiological adjustments in relation to metabolic substrate utilization in the myocardium for coping with high-altitude environments.Methods:We compared the metabolic enzyme activities,including hexokinase(HK),phosphofructokinase(PFK),pyruvate kinase(PK),citrate synthase(CS),carnitine palmitoyl transferase 1(CPT-1),lactic dehydrogenase(LDH),and creatine kinase(CK),and metabolic substrate contents including glucose(Glu),triglyceride(TG),and free fatty acid(FFA)in the myocardium of a typical human commensal species,Eurasian Tree Sparrows(Passer montanus)between the Qinghai-Tibet Plateau(the QTP,3230 m)and low altitude population(Shijiazhuang,80 m),and between sexes.Results:Among the seven metabolic enzymes and three substrates investigated,we identified no significant differences in PK,CPT-1,HK,CS,LDH,and CK activities and TG content of the myocardium between high and low altitude populations.However,the QTP sparrows had significantly lower Glu content and PFK activities but higher FFA content relative to their lowland counterparts.In addition,male sparrows had higher myocardial HK and CS activities relative to females,independent of altitude.Conclusions:Our results showed that the QTP sparrows elevated fatty acid utilization rather than glucose preference in the myocardium relative to lowland counterpart,which contributes to uncovering both the physiological adjustments for adapting to the extreme conditions of the QTP,intraspecifically.展开更多
Water resource availability is the major limiting factor for sustainable development in drylands.Climate change intensifies the conflicting water demands between people and the environment and highlights the importanc...Water resource availability is the major limiting factor for sustainable development in drylands.Climate change intensifies the conflicting water demands between people and the environment and highlights the importance of effective water resource management for achieving a balance between economic development and environmental protection.In 2008,Inner Mongolia,typical dryland in northern China,proposed strict regulations on water exploitation and utilization aimed at achieving sustainable development.Our study is the first to investigate the effectiveness and performance of these long-standing water conservation regulations.Our analyses found that the regulations drove industrial transformation,evidenced by the decreasing proportion of environmentally harmful industries such as coal and steel,and the increasing proportion of tertiary industries(especially tourism).Following industrial transformation,economic development decoupled from industrial water consumption and subsequently led to reduced negative environmental impacts.Based on these results,adaptive strategies were developed for 12 cities by revealing and integrating their development pathways and relative status in achieving sustainable development.Integration and cooperation between cities were proposed,e.g.,a water trade agreement between eastern Inner Mongolia(an economically underdeveloped region with relatively abundant water resources)and central Inner Mongolia(an economically developed region with high water stress).Such an agreement may enable the holistic achievement of sustainable development across regions.By integrating the findings of our research,our study presents a reproducible framework for water-management-based sustainable development strategies in drylands.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.51478435,11402150,and 11172268)
文摘Green's functions for Biot's dynamic equation in the frequency domain can be a highly useful tool for the investigation of dynamic responses of a saturated porous medium. Its applications are found in soil dynamics, seismology, earthquake engineering,rock mechanics, geophysics, and acoustics. However, the mathematical work for deriving it can be daunting. Green's functions have been presented utilizing an analogy between the dynamic thermoelasticity and the dynamic poroelasticity in the frequency domain using the u-p formulation. In this work, a special term "decoupling coefficient" for the decomposition of the fast and slow dilatational waves is proposed and expressed to present a new methodology for deriving the poroelastodynamic Green's functions. The correctness of the solution is demonstrated by numerically comparing the current solution with Cheng's previous solution. The separation of the two waves in the present methodology allows the more accurate evaluation of Green's functions, particularly the solution of the slow dilatational wave. This can be advantageous for the numerical implementation of the boundary element method(BEM) and other applications.
基金supported by the National Natural Science Foundation of China(NSFC,No.31971413)to DL and NSFC(No.31770445)to YWthe Second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK0501)+2 种基金the Natural Science Foundation of Hebei Province(NSFHB,C2020205038)to DLthe Foundation of Hebei Normal University(L2019B26)to CJthe Post-doctoral Research Programm to PD。
文摘Background:Efficient and selective utilization of metabolic substrates is one of the key strategies in high-altitude animals to cope with hypoxia and hypothermia.Previous findings have shown that the energy substrate utilization of highland animals varies with evolutionary history and phylogeny.The heart is a proxy for the cardiopulmonary system,and the metabolic substrate utilization in the myocardium is also under the strong selective pressure of chronically hypoxic and hypothermic environments.However,little information is available on the physiological adjustments in relation to metabolic substrate utilization in the myocardium for coping with high-altitude environments.Methods:We compared the metabolic enzyme activities,including hexokinase(HK),phosphofructokinase(PFK),pyruvate kinase(PK),citrate synthase(CS),carnitine palmitoyl transferase 1(CPT-1),lactic dehydrogenase(LDH),and creatine kinase(CK),and metabolic substrate contents including glucose(Glu),triglyceride(TG),and free fatty acid(FFA)in the myocardium of a typical human commensal species,Eurasian Tree Sparrows(Passer montanus)between the Qinghai-Tibet Plateau(the QTP,3230 m)and low altitude population(Shijiazhuang,80 m),and between sexes.Results:Among the seven metabolic enzymes and three substrates investigated,we identified no significant differences in PK,CPT-1,HK,CS,LDH,and CK activities and TG content of the myocardium between high and low altitude populations.However,the QTP sparrows had significantly lower Glu content and PFK activities but higher FFA content relative to their lowland counterparts.In addition,male sparrows had higher myocardial HK and CS activities relative to females,independent of altitude.Conclusions:Our results showed that the QTP sparrows elevated fatty acid utilization rather than glucose preference in the myocardium relative to lowland counterpart,which contributes to uncovering both the physiological adjustments for adapting to the extreme conditions of the QTP,intraspecifically.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0304-02)Joint Chinese Academy of Sciences(CAS)-Max Planck Society(MPG)Research Project(HZXM20225001MI)+3 种基金the Strategic Priority Research Program A of Chinese Academy of Sciences(XDA20050104)the National Natural Science Foundation of China(42041005)CAS Light of West China Programthe Fundamental Research Funds for the Central Universities。
基金supported by the CAS Strategic Priority Research Programme(No.XDA20050103)the International Partnership Program of Chinese Academy of Sciences(No.121311KYSB20170004-04)and the National Natural Science Foundation of China(Grant No.42001267).
文摘Water resource availability is the major limiting factor for sustainable development in drylands.Climate change intensifies the conflicting water demands between people and the environment and highlights the importance of effective water resource management for achieving a balance between economic development and environmental protection.In 2008,Inner Mongolia,typical dryland in northern China,proposed strict regulations on water exploitation and utilization aimed at achieving sustainable development.Our study is the first to investigate the effectiveness and performance of these long-standing water conservation regulations.Our analyses found that the regulations drove industrial transformation,evidenced by the decreasing proportion of environmentally harmful industries such as coal and steel,and the increasing proportion of tertiary industries(especially tourism).Following industrial transformation,economic development decoupled from industrial water consumption and subsequently led to reduced negative environmental impacts.Based on these results,adaptive strategies were developed for 12 cities by revealing and integrating their development pathways and relative status in achieving sustainable development.Integration and cooperation between cities were proposed,e.g.,a water trade agreement between eastern Inner Mongolia(an economically underdeveloped region with relatively abundant water resources)and central Inner Mongolia(an economically developed region with high water stress).Such an agreement may enable the holistic achievement of sustainable development across regions.By integrating the findings of our research,our study presents a reproducible framework for water-management-based sustainable development strategies in drylands.