Aims While using phylogenetic and functional approaches to test the mechanisms of community assembly,functional traits often act as the proxy of niches.However,there is little detailed knowledge regarding the correlat...Aims While using phylogenetic and functional approaches to test the mechanisms of community assembly,functional traits often act as the proxy of niches.However,there is little detailed knowledge regarding the correlation between functional traits of tree species and their niches in local communities.We suggest that the co-varying correlation between functional traits and niches should be the premise for using phylogenetic and functional approaches to test mechanisms of community assembly.Using functional traits,phylogenetic and environmental data,this study aims to answer the questions:(i)within local communities,do functional traits of co-occurring species covary with their environmental niches at the species level?and(ii)what is the key ecological process underlying community assembly in Xishuangbanna and Ailaoshan forest dynamic plots(FDPs)?Methods We measured seven functional traits of 229 and 36 common species in Xishuangbanna and Ailaoshan FDPs in tropical and subtropical China,respectively.We also quantified the environmental niches for these species based on conditional probability.We then analyzed the correlations between functional traits and environmental niches using phylogenetic independent contrasts.After examining phylogenetic signals of functional traits using Pagel’sλ,we quantified the phylogenetic and functional dispersion along environmental gradients within local tree communities.Important Findings For target species,functional traits do co-vary with environmental niches at the species level in both of the FDPs,supporting that functional traits can be used as a proxy for local-scale environmental niches.Functional traits show significant phylogenetic signals in both of the FDPs.We found that the phylogenetic and functional dispersion were significantly clustered along topographical gradients in the Ailaoshan FDP but overdispersion in the Xishuangbanna FDP.These patterns of phylogenetic and functional dispersion suggest that environmental filtering plays a key role in structuring local tree 展开更多
Repolarization heterogeneity(RH)is an intrinsic property of ventricular myocardium and the reason for T-wave formation on electrocardiogram(ECG).Exceeding the physiologically based RH level is associated with appearan...Repolarization heterogeneity(RH)is an intrinsic property of ventricular myocardium and the reason for T-wave formation on electrocardiogram(ECG).Exceeding the physiologically based RH level is associated with appearance of life-threatening ventricular arrhythmias and sudden cardiac death.In this regard,an accurate and comprehensive evaluation of the degree of RH parameters is of importance for assessment of heart state and arrhythmic risk.This review is devoted to comprehensive consideration of RH phenomena in terms of electrophysiological processes underlying RH,cardiac electric field formation during ventricular repolarization,as well as clinical significance of RH and its reflection on ECG parameters.The formation of transmural,apicobasal,left-toright and anterior-posterior gradients of action potential durations and end of repolarization times resulting from the heterogenous distribution of repolarizing ion currents and action potential morphology throughout the heart ventricles,and the different sensitivity of myocardial cells in different ventricular regions to the action of pharmacological agents,temperature,frequency of stimulation,etc.,are being discussed.The review is focused on the fact that RH has different aspects–temporal and spatial,global and local;ECG reflection of various RH aspects and their clinical significance are being discussed.Strategies for comprehensive assessment of ventricular RH using different ECG indices reflecting various RH aspects are presented.展开更多
Under the excitation of elastic waves,local fluid flow in a complex porous medium is a major cause for wave dispersion and attenuation.When the local fluid flow process is simulated with wave propagation equations in ...Under the excitation of elastic waves,local fluid flow in a complex porous medium is a major cause for wave dispersion and attenuation.When the local fluid flow process is simulated with wave propagation equations in the double-porosity medium,two porous skeletons are usually assumed,namely,host and inclusions.Of them,the volume ratio of inclusion skeletons is low.All previous studies have ignored the consideration of local fluid flow velocity field in inclusions,and therefore they can not completely describe the physical process of local flow oscillation and should not be applied to the situation where the fluid kinetic energy in inclusions cannot be neglected.In this paper,we analyze the local fluid flow velocity fields inside and outside the inclusion,rewrite the kinetic energy function and dissipation function based on the double-porosity medium model containing spherical inclusions,and derive the reformulated Biot-Rayleigh(BR)equations of elastic wave propagation based on Hamilton’s principle.We present simulation examples with different rock and fluid types.Comparisons between BR equations and reformulated BR equations show that there are significant differences in wave response characteristics.Finally,we compare the reformulated BR equations with the previous theories and experimental data,and the results show that the theoretical results of this paper are correct and effective.展开更多
Optical nanoantennas can convert propagating light to local fields.The local-field responses can be engineered to exhibit nontrivial features in spatial,spectral and temporal domains,where local-field interferences pl...Optical nanoantennas can convert propagating light to local fields.The local-field responses can be engineered to exhibit nontrivial features in spatial,spectral and temporal domains,where local-field interferences play a key role.Here,we design nearly fully controllable local-field interferences in the nanogap of a nanoantenna,and experimentally demonstrate that in the nanogap,the spectral dispersion of the local-field response can exhibit tuneable Fano lineshapes with nearly vanishing Fano dips.A single quantum dot is precisely positioned in the nanogap to probe the spectral dispersions of the local-field responses.By controlling the excitation polarization,the asymmetry parameter q of the probed Fano lineshapes can be tuned from negative to positive values,and correspondingly,the Fano dips can be tuned across a broad spectral range.Notably,at the Fano dips,the local-field intensity is strongly suppressed by up to ~50-fold,implying that the hot spot in the nanogap can be turned into a cold spot.The results may inspire diverse designs of local-field responses with novel spatial distributions,spectral dispersions and temporal dynamics,and expand the available toolbox for nanoscopy,spectroscopy,nano-optical quantum control and nanolithography.展开更多
Based on the local discontinuous Galerkin methods for time-dependent convection-diffusion systems newly developed by Corkburn and Shu,according to the form of the generalized convection-diffusion equations which model...Based on the local discontinuous Galerkin methods for time-dependent convection-diffusion systems newly developed by Corkburn and Shu,according to the form of the generalized convection-diffusion equations which model the radial porous flow with dispersion and adsorption,a local discontinuous Galerkin method for radial porous flow with dispersion and adsorption was developed,a high order accurary new scheme for radial porous flow is obtained.The presented method was applied to the numerical tests of two cases of radial porous,i.e., the convection-dispersion flow and the convection-dispersion-adsorption flow,the corresponding parts of the numerical results are in good agreement with the published solutions,so the presented method is reliable.Reckoning of the computational cost also shows that the method is practicable.展开更多
Phase and group velocities of 15-70 s Rayleigh waves propagating across the Iberian Penin- sula have been transformed into local dispersion curves by linear inversion of travel times. The procedure permits that the wa...Phase and group velocities of 15-70 s Rayleigh waves propagating across the Iberian Penin- sula have been transformed into local dispersion curves by linear inversion of travel times. The procedure permits that the waveform dispersion to be obtained as a continuous period-dependent velocity function at grid points belonging to the area probed by the waves, thus providing phase- and group-velocity contour maps for several periods within the interval of interest. The regionalization process rests on a homoge- neous initial data set in which the number of observations remains almost constant for all periods of reference. Damped least-squares inversion of the local dispersion curves for shear-wave velocity structure is performed to obtain depth-dependent S-wave velocity profiles at the grid points covering the model region. The reliability of the results should improve significantly owing to the use of phase and group velocities simultaneously. On this basis, we have built horizontal depth sections that give an updated view of the seismic velocity structure of the peninsula at lithospheric and upper mantle depths （20--200 km）. After averaging all the pure-path S-wave velocities previously determined at each grid point, the velocity- depth models so obtained for major tectonic units allow the comparison between the Hercynian basement and other areas of Mesozoic folding and Tertiary hasins展开更多
基金National Natural Science Foundation of China(31000201,31370445,31061160188)National Key Basic Research Program of China(2014CB954104)the West Light Foundation of Chinese Academy of Sciences and the Special Program for Basic Research of the Ministry of Science and Technology of China(2012FY10400,2011FY120200).
文摘Aims While using phylogenetic and functional approaches to test the mechanisms of community assembly,functional traits often act as the proxy of niches.However,there is little detailed knowledge regarding the correlation between functional traits of tree species and their niches in local communities.We suggest that the co-varying correlation between functional traits and niches should be the premise for using phylogenetic and functional approaches to test mechanisms of community assembly.Using functional traits,phylogenetic and environmental data,this study aims to answer the questions:(i)within local communities,do functional traits of co-occurring species covary with their environmental niches at the species level?and(ii)what is the key ecological process underlying community assembly in Xishuangbanna and Ailaoshan forest dynamic plots(FDPs)?Methods We measured seven functional traits of 229 and 36 common species in Xishuangbanna and Ailaoshan FDPs in tropical and subtropical China,respectively.We also quantified the environmental niches for these species based on conditional probability.We then analyzed the correlations between functional traits and environmental niches using phylogenetic independent contrasts.After examining phylogenetic signals of functional traits using Pagel’sλ,we quantified the phylogenetic and functional dispersion along environmental gradients within local tree communities.Important Findings For target species,functional traits do co-vary with environmental niches at the species level in both of the FDPs,supporting that functional traits can be used as a proxy for local-scale environmental niches.Functional traits show significant phylogenetic signals in both of the FDPs.We found that the phylogenetic and functional dispersion were significantly clustered along topographical gradients in the Ailaoshan FDP but overdispersion in the Xishuangbanna FDP.These patterns of phylogenetic and functional dispersion suggest that environmental filtering plays a key role in structuring local tree
文摘Repolarization heterogeneity(RH)is an intrinsic property of ventricular myocardium and the reason for T-wave formation on electrocardiogram(ECG).Exceeding the physiologically based RH level is associated with appearance of life-threatening ventricular arrhythmias and sudden cardiac death.In this regard,an accurate and comprehensive evaluation of the degree of RH parameters is of importance for assessment of heart state and arrhythmic risk.This review is devoted to comprehensive consideration of RH phenomena in terms of electrophysiological processes underlying RH,cardiac electric field formation during ventricular repolarization,as well as clinical significance of RH and its reflection on ECG parameters.The formation of transmural,apicobasal,left-toright and anterior-posterior gradients of action potential durations and end of repolarization times resulting from the heterogenous distribution of repolarizing ion currents and action potential morphology throughout the heart ventricles,and the different sensitivity of myocardial cells in different ventricular regions to the action of pharmacological agents,temperature,frequency of stimulation,etc.,are being discussed.The review is focused on the fact that RH has different aspects–temporal and spatial,global and local;ECG reflection of various RH aspects and their clinical significance are being discussed.Strategies for comprehensive assessment of ventricular RH using different ECG indices reflecting various RH aspects are presented.
基金supported by the National Natural Science Foundation of China(Grant No.41104066)RIPED Youth Innovation Foundation(Grant No.2010-A-26-01)+1 种基金the National Basic Research Program of China(Grant No.2014CB239006)the Open fund of SINOPEC Key Laboratory of Geophysics(Grant No.WTYJY-WX2013-04-18)
文摘Under the excitation of elastic waves,local fluid flow in a complex porous medium is a major cause for wave dispersion and attenuation.When the local fluid flow process is simulated with wave propagation equations in the double-porosity medium,two porous skeletons are usually assumed,namely,host and inclusions.Of them,the volume ratio of inclusion skeletons is low.All previous studies have ignored the consideration of local fluid flow velocity field in inclusions,and therefore they can not completely describe the physical process of local flow oscillation and should not be applied to the situation where the fluid kinetic energy in inclusions cannot be neglected.In this paper,we analyze the local fluid flow velocity fields inside and outside the inclusion,rewrite the kinetic energy function and dissipation function based on the double-porosity medium model containing spherical inclusions,and derive the reformulated Biot-Rayleigh(BR)equations of elastic wave propagation based on Hamilton’s principle.We present simulation examples with different rock and fluid types.Comparisons between BR equations and reformulated BR equations show that there are significant differences in wave response characteristics.Finally,we compare the reformulated BR equations with the previous theories and experimental data,and the results show that the theoretical results of this paper are correct and effective.
基金supported by the National Key Research and Development Program of China(2017YFA0205700)the National Natural Science Foundation of China(11621101,61774131,91833303)+2 种基金the Fundamental Research Funds for the Central Universities(2017FZA5001,2018FZA5001)the China Postdoctoral Science Foundation(2017M621920,2017M622722)the Science and Technology Department of Zhejiang Province and the Guangdong Innovative Research Team Program(201001D0104799318).
文摘Optical nanoantennas can convert propagating light to local fields.The local-field responses can be engineered to exhibit nontrivial features in spatial,spectral and temporal domains,where local-field interferences play a key role.Here,we design nearly fully controllable local-field interferences in the nanogap of a nanoantenna,and experimentally demonstrate that in the nanogap,the spectral dispersion of the local-field response can exhibit tuneable Fano lineshapes with nearly vanishing Fano dips.A single quantum dot is precisely positioned in the nanogap to probe the spectral dispersions of the local-field responses.By controlling the excitation polarization,the asymmetry parameter q of the probed Fano lineshapes can be tuned from negative to positive values,and correspondingly,the Fano dips can be tuned across a broad spectral range.Notably,at the Fano dips,the local-field intensity is strongly suppressed by up to ~50-fold,implying that the hot spot in the nanogap can be turned into a cold spot.The results may inspire diverse designs of local-field responses with novel spatial distributions,spectral dispersions and temporal dynamics,and expand the available toolbox for nanoscopy,spectroscopy,nano-optical quantum control and nanolithography.
文摘Based on the local discontinuous Galerkin methods for time-dependent convection-diffusion systems newly developed by Corkburn and Shu,according to the form of the generalized convection-diffusion equations which model the radial porous flow with dispersion and adsorption,a local discontinuous Galerkin method for radial porous flow with dispersion and adsorption was developed,a high order accurary new scheme for radial porous flow is obtained.The presented method was applied to the numerical tests of two cases of radial porous,i.e., the convection-dispersion flow and the convection-dispersion-adsorption flow,the corresponding parts of the numerical results are in good agreement with the published solutions,so the presented method is reliable.Reckoning of the computational cost also shows that the method is practicable.
文摘Phase and group velocities of 15-70 s Rayleigh waves propagating across the Iberian Penin- sula have been transformed into local dispersion curves by linear inversion of travel times. The procedure permits that the waveform dispersion to be obtained as a continuous period-dependent velocity function at grid points belonging to the area probed by the waves, thus providing phase- and group-velocity contour maps for several periods within the interval of interest. The regionalization process rests on a homoge- neous initial data set in which the number of observations remains almost constant for all periods of reference. Damped least-squares inversion of the local dispersion curves for shear-wave velocity structure is performed to obtain depth-dependent S-wave velocity profiles at the grid points covering the model region. The reliability of the results should improve significantly owing to the use of phase and group velocities simultaneously. On this basis, we have built horizontal depth sections that give an updated view of the seismic velocity structure of the peninsula at lithospheric and upper mantle depths （20--200 km）. After averaging all the pure-path S-wave velocities previously determined at each grid point, the velocity- depth models so obtained for major tectonic units allow the comparison between the Hercynian basement and other areas of Mesozoic folding and Tertiary hasins
