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Planar matrices and arrays of Feynman diagrams

Communications in Theoretical Physics 2024年第3期76卷 15-32页

作者： Freddy Cachazo Alfredo Guevara Bruno Umbert Yong Zhang Perimeter Institute for Theoretical Physics WaterlooON N2L 2Y5Canada Department of Physics and Astronomy University of WaterlooWaterlooON N2L 3G1Canada CECs Valdivia y Departamento de Física Universidad de ConcepciónCasilla 160-CConcepciónChile Center for the Fundamental laws of Nature Society of Fellows and Black Hole InitiativeHarvard UniversityCambridgeMA 02138United States of America Department of Applied Mathematics Western UniversityLondonON N6A 5B7Canada cas key laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesNo.19A Yuquan RoadBeijing 100049China

Recently,planar collections of Feynman diagrams were proposed by Borges and one of the authors as the natural generalization of Feynman diagrams for the computation of k=3 biadjoint *** collections are one-dimensional arrays of metric trees satisfying an induced planarity and compatibility *** this work,we introduce planar matrices of Feynman diagrams as the objects that compute k=4 biadjoint *** are symmetric matrices of metric trees satisfying compatibility *** introduce two notions of combinatorial bootstrap techniques for finding collections from Feynman diagrams and matrices from *** applications of the first,we find all 693,13612 and 346710 collections for(k,n)=(3,7),(3,8)and(3,9),*** applications of the second kind,we find all90608 and 30659424 planar matrices that compute(k,n)=(4,8)and(4,9)biadjoint amplitudes,*** an example of the evaluation of matrices of Feynman diagrams,we present the complete form of the(4,8)and(4,9)biadjoint *** also start a study of higher-dimensional arrays of Feynman diagrams,including the combinatorial version of the duality between(k,n)and(n-k,n)objects.

关键词： Feynman diagrams biadjoint amplitudes tropical Grassmannian

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Devonian integrative stratigraphy and timescale of China

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Science China Earth Sciences 2019年第1期62卷 112-134页

作者： Wenkun QIE Xueping MA Honghe XU li QIAO Kun lIANG Wen GUO Junjun SONG Bo CHEN Jianfeng lU cas key laboratory of economic stratigraphy and Palaeogeography Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment Chinese Academy of Sciences School of Earth and Space Sciences Peking University State key laboratory of Palaeobiology and stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment Chinese Academy of Sciences Nanjing Institute of Geology and Palaeontology and Center for Excellence in life and Paleoenvironment Chinese Academy of Sciences

The Global Boundary Stratotype Sections and Points(GSSPs) for the bases of all seven international Devonian stages have been formally defined and ratified by IUGS till 1996, and nowadays, the main tasks for Devonian stratigraphers include further subdivision of these standard stages, strictly constrained absolute ages for the boundaries, and precise neritic-pelagic and marine-terrestrial correlations using multidisciplinary stratigraphy methods. Establishment of high-resolution Devonian integrative stratigraphy framework and timescale of China would play an important role in improving regional and international correlation, facilitating the recognition of important stratigraphic levels in different paleogeographic settings, and understanding the evolution pattern of biota, paleoclimate and paleoenvironment during this critical interval. Based on well-studied bio-and chronostratigraphy of Devonian in South China and adjacent areas, in combination with recent achievements in carbon isotope stratigraphy, event stratigraphy and radioactive isotope ages, this paper briefly summarize the research history and current status of Devonian chronostratigraphy of China, and for the first time introduce Devonian integrative stratigraphy framework of *** to date, few studies have been conducted on the astronomical cyclostratigraphy and high-resolution radioactive isotope dating in Devonian of China, which should be our main focuses in the near future.

关键词： Devonian Chronostratigraphy Biostratigraphy Carbon isotope stratigraphy Event stratigraphy

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Changes of vegetation in southern China

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Science China Earth Sciences 2019年第8期62卷 1316-1328页

作者： Weiming WANG Chunhai lI Junwu SHU Wei CHEN cas key laboratory of economic stratigraphy and Palaeogeography Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy of SciencesNanjing210008China State key laboratory of lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing210008China

In order to reveal the changes of vegetation in southern China since the last Glacial Maximum, we have established high-resolution time scales and palynological sequences of borehole profiles by drilling cores in some weak areas of the research to restore vegetation changes over the past 20,000 years on the basis of previous work. This paper gives the vegetation zoning maps of 18, 9 and 6 ka BP respectively in southern China, and describes the distribution characteristics of plants in different zones/subzones. The results show that the vegetation zonations around 18 ka BP were significantly different from that at *** appeared in turn with Cold-temperate coniferous forest and alpine meadow steppe zone, and Temperate mixed coniferous and broad-leaved forest zone/warm temperate deciduous broad-leaved forest zone from northwest to southeast in the west, and Temperate mixed coniferous and broad-leaved forest zone, Warm temperate deciduous broad-leaved forest zone, and Northern subtropical mixed evergreen and deciduous broad-leaved forest zone from north to south in the central and east. The vegetation distribution around 9 ka BP changed distinctively. Except that the northwest part was located in Mountain temperate mixed coniferous and broad-leaved forest zone, the vegetation in other areas occurred in turn with North subtropical mixed evergreen and deciduous broad-leaved forest subzone, Mid-subtropical typical evergreen broad-leaved forest subzone, and South subtropical monsoon evergreen broad-leaved forest subzone/Tropical seasonal rainforest and rainforest zone from north to *** was little change in the appearance of vegetation zonations between 6 and 9 ka BP, but the northern edge of each vegetation belt moved a little northward, reflecting that the overall climate became warmer around 6 ka BP. The vegetation changes in southern China over the past 20,000 years were largely driven by environmental changes. Climate change was the main factor affecting t

关键词： Vegetation changes 18 ka BP 9 ka BP 6 ka BP Environmental change Southern China

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Ordovician integrative stratigraphy and timescale of China

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Science China Earth Sciences 2019年第1期62卷 61-88页

作者： Yuandong ZHANG Renbin ZHAN Yongyi ZHEN Zhihao WANG Wenwei YUAN Xiang FANG Xuan MA Junpeng ZHANG cas key laboratory of economic stratigraphy and Palaeogeography Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment Chinese Academy of Sciences Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences University of Chinese Academy of Sciences State key laboratory of Palaeobiology and stratigraphy (Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences) Geological Survey of New South Wales W.B.Clarke Geoscience Centre

In this chapter, starting with a brief review of the research history and current status in the studies of the Ordovician chronostratigraphy in China, the subdivision of the Ordovician System, definition and recognition of its series and stage boundaries, and possible stratigraphic gaps are discussed in details in order to establish a multidisciplinary stratigraphic correlation through an integrated approach including lithostratigraphy, biostratigraphy, radiometric dating, chemostratigraphy and magnetostratigraphy. Being internationally accepted, the Ordovician System is now subdivided into three series and seven stages, in ascending order, lower(Tremadocian, Floian), Middle(Dapingian, Darriwilian) and Upper series(Sandbian, Katian,Hirnantian). Three of the seven "Golden Spikes" defining the bases of the Ordovician stages, which were established in 1997–2007, are located in China. As a regionally applied chronostratigraphy, the Ordovician System was subdivided in China into lower(Xinchangian, Yiyangian), Middle(Dapingian, Darriwilian) and Upper series(Neichiashanian, Chientangkiangian,Hirnantian). This scheme agrees largely with the standard international classification, which can actually be directly applied to China, except for some special circumstances where the Neichiashanian and Chientangkiangian stages of the Upper Ordovician are used. Based on the new studies in recent years and distinctions and differences recognized in the development of the Ordovician System in the constituent terranes of China, a new framework for correlation among the major Chinese palaeoplates or terranes, e.g. South China, North China(including Tarim and Qaidam) and Xizang(Tibet)-western Yunnan, has been established. However, it has been recognized herein that uncertainties still remain on defining the base of the Tremadocian,Dapingian and Katian, and on the correlation between different mega-facies. More specifically, for the Tremadocian, the precise correlation of its base will depe

关键词： Ordovician System Geological age Chronostratigraphy Chemostratigraphy Biostratigraphy

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Sedimentary Evolution and Transgressions of the Western Subei Basin in Eastern China since the late Pliocene

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Acta Geologica Sinica(English Edition) 2019年第1期93卷 155-166页

作者： CHENG Yu lI Xiangqian SHU Junwu BAI Shibiao ZHAO Zengyu ZHANG Xiangyun GUO Gang ZHANG Ping lIN Jingxing The Institute of Geological Survey of Jiangsu Province Nanjing Institute of Geology and Palaeontology CAS Key Laboratory of Economic Stratigraphy and PalaeogeographyChinese Academy of Sciences School of Geography Science Nanjing Normal University Institute of Geology Chinese Academy of Geological Sciences

Sedimentary sequences in the Subei Basin are complex and have been affected by interactions between the ocean and rivers since the late Pliocene, including the Yellow River, Huaihe River, and the Yangtze River. This sedimentary evolution, in particular the timing of Pleistocene transgressions, has long been a matter of controversy owing to the lack of precise chronological evidence. The aim of this study is to explore the evolution of the sedimentary environment throughout the past 3.00 Ma in this region on the basis of a comprehensive analysis of particle size and foraminifera and ostracods collected in the TZK9 core from the Subei Basin combined with geochronological studies of magnetostratigraphy, AMS^(14)C and optically stimulated luminescence(OSl). The results show that fluvial facies in the sedimentary environment from 3.00 to 1.01 Ma. There were fluvial facies and reflects six sea-level high stands from 1.01 to 0.25 Ma. The study area was affected by four large-scale transgressions since 0.25 Ma. The four marine sedimentary layers known as DU7(buried at 48–52 m), DU5(buried at 35–41 m), DU3(buried at 16–23 m), and DU1(buried at 2–4 m) are recorded in the MIS7(210–250 ka), MIS5, MIS3, and Holocene, respectively. The magnitude of the DU5 transgression was identical to that of the DU3 transgression, both were larger than the DU7 transgression, and the DU1 transgression was the weakest. The variation of transgression strength reflects the influence of global changes in sea level, tectonic subsidence, shell ridges, and sand dams. In the TZK9 core, we found evidence of seven sea-level high stands from the Early–Middle Pleistocene, and the first one caused by regional rapid subsidence and could be traced back to 0.83-0.84 Ma. The sea-level high stands and the age of the first one recorded above was different from other cores in eastern China, this was caused by the lack of absolute age control and the differences in paleotopography during this period. This study rec

关键词： foraminifera and ostracods sea-level change transgression Subei Basin

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Extracellular Disintegration of Viral Proteins as an Innovative Strategy for Developing Broad-Spectrum Antivirals Against Coronavirus

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CCS Chemistry 2024年第2期6卷 487-496页

作者： Ke Sun Zhe Ding Xiaoying Jia Haonan Cheng Yingwen li Yan Wu Zhuoyu li Xiaohua Huang Fangxu Pu Entao li Guiyou Wang Wei Wang Yun Ding Gary Wong Sandra Chiu Jiaming lan Aiguo Hu Shanghai key laboratory of Advanced Polymeric Materials School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237 cas key laboratory of Molecular Virology&Immunology Chinese Academy of SciencesShanghai 200031 University of the Chinese Academy of Sciences Beijing 100049 State key laboratory of Virology Center for Biosafety Mega-ScienceWuhan Institute of VirologyChinese Academy of SciencesWuhan 430071 Division of life Sciences and Medicine University of Science and Technology of ChinaHefeiAnhui 230027 Department of Clinical laboratory The First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui 230001

The coronavirus disease 2019(COVID-19)pandemic,caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has claimedmillions of lives and caused innumerable economic losses ***,state-of-the-art treatments still lag behind the continual emergence of new *** to resolving this issue is developing antivirals to deactivate coronaviruses regardless of their structural ***,we report an innovative antiviral strategy involving extracellular disintegration of viral proteins with hyperanion-grafted enediyne(EDY)*** core EDY generates reactive radical species and causes significant damage to the spike protein of coronavirus,while the hyperanion groups ensure negligible cytotoxicity of the *** EDYs exhibit antiviral activity down to nanomolar concentrations,and the selectivity index of up to 20,000 against four kinds of human coronavirus,including the SARS-CoV-2 Omicron variant,suggesting the high potential of this new strategy in combating the COVID-19 pandemic and a future“disease X.”

关键词： enediyne broad spectrum antiviral protein disintegration coronavirus polyanions

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Fossil liverworts from the lower Cretaceous Huolinhe Formation in Inner Mongolia, China

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Acta Geologica Sinica(English Edition) 2016年第3期90卷 838-846页

作者： lI Ruiyun WANG Xuelian JIN Peihong MA Fujun YAN Defei lIN Zhicheng SUN Bainian School of Earth Sciences&key laboratory of Mineral Resources in Western China(Gansu Province) Lanzhou University Northwest University Museum Northwest University key laboratory of economic stratigraphy and Palaeogeography Nanjing Institute of Geology and PalaeontologyCAS School of Petroleum Engineering Chongqing University of Science & Technology

A new genus and species, Rebouliothallus huolinhensis sp. nov., and two uncertain species, Ricciopsis sp. and Hepaticites sp., are described. The fossils were collected from the lower Cretaceous Huolinhe Formation of Huolinhe Basin, northeastern China. The new genus Rebouliothallus was established in the Aytoniaceae family of Marchantiales. Rebouliothallus huolinhensis appears to be quite similar to species of the extant genus Reboulia Raddi. The species is characterized by the relatively large ventral scales. Ventral scales are large, imbricate and arranged in two rows on the ventral surface. Rhizoids are either pegged or smooth. Ricciopsis sp. is characterized by the rosette- forming thallus. Hepaticites sp. shows some similarities to liverworts. Of the forty-nine Early Cretaceous floras of China, only two floras, one from the Huolinhe basin, Inner Mongolia and the other from the Jixi Basin, Heilongjiang Province, contain fossil liverworts. The rare fossil liverwort records in the Early Cretaceous floras of China may be the result of taphonomic bias.

关键词： Rebouliothallus Ricciopsis Hepaticites Early Cretaceous Huolinhe Formation

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Depositional Environments of the Upper Permian Quartzose Sandstone(Shandong Province, North China): Insight from Trace Element Geochemistry

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Journal of Earth Science 2015年第2期26卷 273-284页

作者： Dawei lü Zengxue li Jitao Chen Ying liu Zengqi Zhang Jipo liang Haiyan liu key laboratory of Depositional Mineralization & Sedimentary Mineral (SDUST) key laboratory of economic stratigraphy and Palaeogeography Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Geological Institute of Shandong Province

The depositional environment of the Upper Permian quartzose sandstone （Kuishan sandstone in Shihezi Formation of Upper Permian） in the North China epicontinental basin is controversial. In order to test the previous hypotheses, we analyzed sedimentological characteristics of the Kuishan sandstones in outcrops and boreholes, and carried out trace element geochemical analysis by electron probe microanalyzer. Three lithofacies were recognized, including normal-graded conglomerate （Cng）, trough and planar cross-bedded coarse sandstone （CStpc）, and planar cross-bedded medium sandstone （MSpc）. Normal-graded conglomerate （Cng） formed in the meandering river or deltaic distributary channels. Trough and planar cross-bedded coarse sandstone （CStpc） formed in meandering river or distributary channels of near-source deltaic plain. Planar cross-bedded medium sandstone （MSpc） formed in the siliciclastic beach with highto moderate-energy conditions. By the petrology and trace elements analysis, three relatively large-scale transgressions were revealed. Each transgression was reflected by the lower content of Ba and ratios of Fe/Mn, and the high content of B and ratios of B/Ga. The ratios of Ni/Co of all samples are all lower than 2, suggesting oxygen-enriched shallower water en- vironment during deposition of the Kuishan sandstones.

关键词： Kuishan sandstone electron probe microanalysis (EPMA) depositional environment transgression regression.

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New records of Jurassic petrified wood in Jianchang of western liaoning,China and their palaeoclimate implications

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Science China Earth Sciences 2015年第12期58卷 2154-2164页

作者： TIAN Ning XIE AoWei WANG YongDong JIANG ZiKun lI liQin YIN Yalei ZHU ZhiPeng WANG JiaJia College of Palaeontology Shenyang Normal University State key laboratory of Palaeobiology and stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences key laboratory for Evolution of Past life in Northeast Asia Ministry of Land and Resources Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences key laboratory of economic stratigraphy and Palaeogeography Chinese Academy of Sciences Chinese Academy of Geological Sciences

Diverse and rich fossil wood records have been documented from the Mesozoic of liaoning Province, NE China. The Tiaojishan Formation(mainly distributed in Beipiao, Chaoyang, Fuxin and Jianchang regions) is one of the most significant horizons for the Jurassic petrified wood in liaoning Province. Previously, wood fossils of this formation were mainly reported in Beipiao and Chaoyang regions, whereas fossil wood record was merely known in Jianchang region. Here we describe new fossil wood specimens from the Tiaojishan Formation in Jianchang County, western liaoning. Two fossil wood taxa, i.e., Protaxodioxylon jianchangense Tian et Wang sp. nov. and Xenoxylon peidense Zheng et Zhang were recognized on the basis of anatomical features. These fossil wood records add new data for understanding the fossil wood diversity, floral composition and palaeoclimate of the Tiaojishan Formation. The occurrence of Xenoxylon and Protaxodioxylon implies a cool temperate, wet and seasonal climate condition with interannual variations during the Middle to late Jurassic transition in western liaoning region.

关键词： fossil wood Xenoxylon Protaxodioxylon Middle to late Jurassic palaeoclimate Tiaojishan Formation western liaoning

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Oxygenation in carbonate microbialites and associated facies after the end-Permian mass extinction:Problems and potential solutions

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Journal of Palaeogeography 2018年第1期7卷 32-47页

作者： Stephen Kershaw Hao Tang Yue li li Guo Department of life Sciences Kingston Lane Brunel University State key laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University cas key laboratory of economic stratigraphy and Palaeogeography Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences casP Department of Earth Sciences University of Cambridge

Carbonate sediments deposited in normally-oxygenated shallow ocean waters of the latest Permian period, immediately prior to the end-Permian mass extinction, contain well-developed diverse shelly faunas. After the extinction of these skeletal metazoans, the sediments commonly comprise microbialites(regarded by most authors as benthic) and associated facies bearing evidence interpreted by many authors to indicate reduced oxygenation of the shallow ocean waters. However, the evidence of oxygenation state is inconsistent and the sequences have gaps, indicated in the following 5 points:1) Shelly fossils occur commonly in post-extinction shallow marine limestones, and likely to have been aerated in contact with the atmosphere. Nevertheless, although the largest mass extinction in Earth history may have caused reduced body size in shelly organisms, such reduction is arguably due to environmental stress of lowered oxygenation. Discriminating between these controls remains a challenge.2) Abundant pyrite framboids in many post-extinction limestones are interpreted by several authors as indicating dysoxic contemporaneous waters, so the organisms that lived there, now shelly fossils, were dysaerobic. However, verification is problematic because pyrite framboids scattered amongst shelly fossils cannot have formed amongst living organisms, which need at least some oxygen; synsedimentary framboid formation requires anoxic conditions in the redox boundary where sulphate-reducing processes work. Thus, framboids and shelly fossils found together means taphonomic mixing of sediments, destroying original depositional relationships so that it is not possible to determine whether the shells were aerobic or dysaerobic prior to sediment mixing. Furthermore, diagenetic growth of framboids is possible, as is import of previously-formed framboids from deeper water during upwelling. Thus, there is no proof of an environmental link between framboid size and occurrence, and contemporaneous oxyg

关键词： Stromatolite Thrombolite Microbialite Permian-Triassic boundary Pyrite Anoxia

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