A new occurrence of buckthorn fossil leaves is reported from the upper Eocene strata of Markam Basin,southeastern Tibet,China.The leaf margin is either entire or slightly sinuous.Secondary veins are regularly spaced,f...A new occurrence of buckthorn fossil leaves is reported from the upper Eocene strata of Markam Basin,southeastern Tibet,China.The leaf margin is either entire or slightly sinuous.Secondary veins are regularly spaced,forming eucamptodromous venation.These secondaries exist as straight lines from midvein to near margin and then arch abruptly upward and enter into a margin vein.The tertiary veins are densely spaced and parallel,and are percurrent to secondary veins.This leaf architecture conforms with Berhamniphyllum Jones and Dilcher,an extinct fossil genus reported from America.Our fossils are characterized by their dense secondaries,with secondary veins on the upper half portion of the blade accounting for over 40%of all secondaries.A new species,Berhamniphyllum junrongiae Z.K.Zhou,T.X.Wang et J.Huang sp.nov.,is proposed.Further analysis shows that confident assignment among Rhamnidium,Berchemia,and Karwinskia cannot be made based on leaf characters alone.Berhamniphyllum might represent an extinct common ancestor of these genera.In this study,several fossil Berchemia from Yunnan and Shandong are emended and reassigned to Berhamniphyllum.A new complex,namely the Berchemia Complex,is proposed based on morphology,molecular evidence,and the fossil record.This complex contains the fossil leaves of Rhamnidium,Karwinskia,Berchemia,and Berhamniphyllum.The historical biogeography of the Berchemia Complex is also discussed in this paper.This complex might have originated in the late Cretaceous in Colombia,South America,and dispersed to North America via Central America during the Eocene.Subsequently,the complex moved from North America to East Asia via the Bering Land Bridge no later than the late Eocene.Besides,the complex migrated from North America to Europe via the North Atlantic Land Bridge and then migrated further to Africa.In East Asia,it first appeared in Markam on the Qinghai-Tibetan Plateau,and then dispersed to other regions of Asia.展开更多
In this paper,we establish the global well-posedness of the stochastic 3D Leray-αmodel with general fractional dissipation driven by multiplicative noise.This model is the stochastic 3D Navier-Stokes equations regula...In this paper,we establish the global well-posedness of the stochastic 3D Leray-αmodel with general fractional dissipation driven by multiplicative noise.This model is the stochastic 3D Navier-Stokes equations regularized through a smoothing kernel of orderθ1 in the nonlinear term and theθ2-fractional Laplacian.In the case ofθ1≥0 andθ2>0 withθ1+θ2≥5/4,we prove the global existence and uniqueness of strong solutions.The main results not only cover many existing works in the deterministic cases,but also generalize some known results of stochastic models such as the stochastic hyperviscous Navier-Stokes equations and classical stochastic3D Leray-αmodel as the special cases.展开更多
Consider d-dimensional magneto-hydrodynamic(MHD)equations with fractional dissipations driven by multiplicative noise.First,we prove the existence of martingale solutions for stochastic fractional MHD equations in the...Consider d-dimensional magneto-hydrodynamic(MHD)equations with fractional dissipations driven by multiplicative noise.First,we prove the existence of martingale solutions for stochastic fractional MHD equations in the case of d=2,3 andα∧β〉0,whereα,βare the parameters of the fractional dissipations in the equation.Second,for d=2,3 andα∧β≥12+d4,we show the pathwise uniqueness of solutions and then obtain the existence and uniqueness of strong solutions using the Yamada-Watanabe theorem.Furthermore,we establish the exponential mixing property for stochastic MHD equations with degenerate multiplicative noise when d=2,3 andα∧β≥12+d4.展开更多
基金The authors are grateful to two anonymous reviewers for their constructive comments, which significantly improved the manuscript. The authors thank fellow members of staff of the Palaeoecology group in Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences for assistance during sample collection and productive critical discussions Professor Yun Fu from the Central Laboratory of Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences for assistance during the TN mea- surements+1 种基金 Dr. Olesya V. Bondarenko, from the Russian Academy of Sciences, Vladivostok, for her help and support during sample preparation Yi-Min Tian from the Faculty of Land Resource Engi- neering, Kunming University of Science and Technology, for her assistance when preparing and observing thin sections. The authors are grateful to Dr. Andrea Kern from the USGS and Dr. Dayou Zhai from Yunnan University for fruitful discussions and suggestions to improve the manuscript. This study was supported by National Nat- ural Science Foundation of China （U1502231）, the CAS 135 Program （XTBG-F01）, and a grant from the China Scholarship Council to J. Lebreton Anberr6e （2013GCX606）. Shihu Li and Chenglong Deng acknowledge support from the National Natural Science Foundation of China （41404056）, and the State Key Laboratory of Lithospheric Evolution （11431780）. Shu-Feng Li was supported by the Foundation of the State Key Laboratory of Paleobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, CAS （15310）. This work is part of the NECLIME （Neogene Climate of Eurasia） network.
基金supported by the Strategic Priority Research Program of CAS (Grant Nos. XDA2007030102 & XDB26000000)the NSFC (the National Natural Science Foundation of China)-NERC (Natural Environment Research Council of the United Kingdom) joint research program (Grant Nos. 41661134049 & NE/P013805/1)+2 种基金The Second Tibetan Plateau Scientific Expedition and Research Program (STEP), CAS (Grant No. 2019QZKK0705)Youth Innovation Promotion Association, CAS (Grant No. 2017439)Key Research Program of Frontier Sciences, CAS (Grant No. QYZDB-SSW-SMC016)
文摘A new occurrence of buckthorn fossil leaves is reported from the upper Eocene strata of Markam Basin,southeastern Tibet,China.The leaf margin is either entire or slightly sinuous.Secondary veins are regularly spaced,forming eucamptodromous venation.These secondaries exist as straight lines from midvein to near margin and then arch abruptly upward and enter into a margin vein.The tertiary veins are densely spaced and parallel,and are percurrent to secondary veins.This leaf architecture conforms with Berhamniphyllum Jones and Dilcher,an extinct fossil genus reported from America.Our fossils are characterized by their dense secondaries,with secondary veins on the upper half portion of the blade accounting for over 40%of all secondaries.A new species,Berhamniphyllum junrongiae Z.K.Zhou,T.X.Wang et J.Huang sp.nov.,is proposed.Further analysis shows that confident assignment among Rhamnidium,Berchemia,and Karwinskia cannot be made based on leaf characters alone.Berhamniphyllum might represent an extinct common ancestor of these genera.In this study,several fossil Berchemia from Yunnan and Shandong are emended and reassigned to Berhamniphyllum.A new complex,namely the Berchemia Complex,is proposed based on morphology,molecular evidence,and the fossil record.This complex contains the fossil leaves of Rhamnidium,Karwinskia,Berchemia,and Berhamniphyllum.The historical biogeography of the Berchemia Complex is also discussed in this paper.This complex might have originated in the late Cretaceous in Colombia,South America,and dispersed to North America via Central America during the Eocene.Subsequently,the complex moved from North America to East Asia via the Bering Land Bridge no later than the late Eocene.Besides,the complex migrated from North America to Europe via the North Atlantic Land Bridge and then migrated further to Africa.In East Asia,it first appeared in Markam on the Qinghai-Tibetan Plateau,and then dispersed to other regions of Asia.
基金supported by National Natural Science Foundation of China(Grant No.12001247)supported by National Natural Science Foundation of China(Grant Nos.12171208,11831014 and 12090011)+2 种基金supported by National Natural Science Foundation of China(Grant Nos.11931004 and 12090011)Natural Science Foundation of Jiangsu Province(Grant No.BK20201019)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘In this paper,we establish the global well-posedness of the stochastic 3D Leray-αmodel with general fractional dissipation driven by multiplicative noise.This model is the stochastic 3D Navier-Stokes equations regularized through a smoothing kernel of orderθ1 in the nonlinear term and theθ2-fractional Laplacian.In the case ofθ1≥0 andθ2>0 withθ1+θ2≥5/4,we prove the global existence and uniqueness of strong solutions.The main results not only cover many existing works in the deterministic cases,but also generalize some known results of stochastic models such as the stochastic hyperviscous Navier-Stokes equations and classical stochastic3D Leray-αmodel as the special cases.
基金The research of S.Li was supported by the National Natural Science Foundation of China(Grant No.12001247)the Natural Science Foundation of Jiangsu Province(No.BK20201019)+2 种基金the Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.20KJB110015)the Foundation of Jiangsu Normal University(No.19XSRX023)The research of W.Liu was supported by the National Natural Science Foundation of China(Grant Nos.11822106,11831014,12090011)and the PAPD of Jiangsu Higher Education Institutions.
文摘Consider d-dimensional magneto-hydrodynamic(MHD)equations with fractional dissipations driven by multiplicative noise.First,we prove the existence of martingale solutions for stochastic fractional MHD equations in the case of d=2,3 andα∧β〉0,whereα,βare the parameters of the fractional dissipations in the equation.Second,for d=2,3 andα∧β≥12+d4,we show the pathwise uniqueness of solutions and then obtain the existence and uniqueness of strong solutions using the Yamada-Watanabe theorem.Furthermore,we establish the exponential mixing property for stochastic MHD equations with degenerate multiplicative noise when d=2,3 andα∧β≥12+d4.
