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Alterations of soil aggregates and intra-aggregate organic carbon fractions after soil conversion from paddy soils to upland soils:Distribution,mineralization and driving mechanism

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Pedosphere 2024年第1期34卷 121-135页

作者： Longfei KANG Jiamei WU Chunfeng ZHANG Baoguo ZHU Guixin CHU College of Life Science Shaoxing UniversityShaoxing 312000China The Key Laboratory of Oasis Eco-agriculture Xinjiang Production and Construction Group/Department of Resources and Environmental SciencesAgronomy CollegeShihezi UniversityShihezi 832000China Hunan Institute of Agricultural Environment and ecology Changsha 410000China Jiamusi Branch Heilongjiang Academy of Agricultural SciencesJiamusi 154007China

Investigating the impacts of soil conversion on soil organic carbon(OC) content and its fractions within soil aggregates is essential for defining better strategies to improve soil structure and OC sequestration in terrestrial ecosystems. However, the consequences of soil conversion from paddy soil to upland soil for soil aggregates and intra-aggregate OC pools are poorly understood. Therefore, the objective of this study was to quantify the effects of soil conversion on soil aggregate and intra-aggregate OC pool distributions. Four typical rice-producing areas were chosen in North and South China, paired soil samples(upland soil converted from paddy soil more than ten years ago vs. adjacent paddy soil) were collected(0–20 cm) with three replicates in each area. A set of core parameters(OC preservation capacity, aggregate carbon(C) turnover, and biological activity index) were evaluated to assess the responses of intra-aggregate OC turnover to soil conversion. Results showed that soil conversion from paddy soil to upland soil significantly improved the formation of macro-aggregates and increased aggregate stability. It also notably decreased soil intra-aggregate OC pools, including easily oxidized OCa(EOCa), particulate OCa(POCa), and mineral-bound(MOCa) OC, and the sensitivity of aggregate-associated OC pools to soil conversion followed the order: EOCa(average reduction of 21.1%) > MOCa(average reduction of 15.4%) > POCa(average reduction of 14.8%). The potentially mineralizable C(C_(0)) was significantly higher in upland soil than in paddy soil, but the corresponding decay constant(k) was lower in upland soil than in paddy soil. Random forest model and partial correlation analysis showed that EOCa and pH were the important nutrient and physicochemical factors impacting k of C mineralization in paddy soil,while MOCa and C-related enzyme(β-D-cellobiohydrolase) were identified as the key factors in upland soil. In conclusion, this study evidenced that soil conversion

关键词： decay constant easily oxidized organic C macro-aggregate meso-aggregate micro-aggregate mineral-bound organic C particulate organic C potentially mineralizable C

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A Nonlinear Autoregressive Approach to Statistical Prediction of Disturbance Storm Time Geomagnetic Fluctuations Using Solar Data

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Journal of Signal and Information Processing 2014年第2期5卷 42-53页

作者： Joseph M. Caswell Neuroscience research group Laurentian University Sudbury Canada

A nonlinear autoregressive approach with exogenous input is used as a novel method for statistical forecasting of the disturbance storm time index, a measure of space weather related to the ring current which surrounds the Earth, and fluctuations in disturbance storm time field strength as a result of incoming solar particles. This ring current produces a magnetic field which opposes the planetary geomagnetic field. Given the occurrence of solar activity hours or days before subsequent geomagnetic fluctuations and the potential effects that geomagnetic storms have on terrestrial systems, it would be useful to be able to predict geophysical parameters in advance using both historical disturbance storm time indices and external input of solar winds and the interplanetary magnetic field. By assessing various statistical techniques it is determined that artificial neural networks may be ideal for the prediction of disturbance storm time index values which may in turn be used to forecast geomagnetic storms. Furthermore, it is found that a Bayesian regularization neural network algorithm may be the most accurate model compared to both other forms of artificial neural network used and the linear models employing regression analyses.

关键词： Space Weather Geomagnetic Storms Artificial Neural Networks Solar Winds NARX Forecasting Interplanetary Magnetic Field

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How far can one send a photon？

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Frontiers of physics 2015年第6期10卷 95-102页

作者： Nicolas Gisin group of Applied Physics University of Geneva 1211 Geneva 4 Switzerland

The answer to the question How far can one send a photon？ depends heavily on what one means by a photon and on what one intends to do with that photon. For direct quantum communication, the limit is approximately 500 km. For terrestrial quantum communication, near-future technologies based on quantum teleportation and quantum memories will soon enable quantum repeaters that will turn the development of a world-wide-quantum-web （WWQW） into a highly non-trivial engineering problem. For Device-Independent Quantum Information Processing, near-future qubit amplifiers （i.e., probabilistic heralded amplification of the probability amplitude of the presence of photonic qubits） will soon allow demonstrations over a few tens of kilometers.

关键词： quantum communication

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Jurassic-Cretaceous Boundary Strata of the Somanakamura group in NE Japan and their Correlation with Coeval terrestrial Deposits in China

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Acta Geologica Sinica(English Edition) 2015年第1期89卷 285-299页

作者： LI Wei WAN Xiaoqiao Atsushi MATSUOKA ZHANG Shuqin QU Haiying Tsubasa TAMURA Kohei YOSHINO State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Department of Geology Niigata University research Center of Paleontology and Stratigraphy Jilin Univercity

Defining the Jurassic-Cretaceous boundary is a controversy in stratigraphic study of the world. It has been widely accepted that this boundary can be defined at the bottom of Berriasian in Tetbys, with the appearance of the ammonite Berriasellajacobi dating to ca. 145 Ma. However, it is difficult for the widespread terrestrial deposits in China to correlate with the international standard of marine facies. The Somanakamura group in Japan is represented by a succession of marinecontinental transitional strata. It provides a bridge of marine and nonmarine stratigraphic correlation. The ammonite and radiolarian fossils preserved in this group suggest an age from Bajocian to early Valanginian. The J-K boundary was defined in or atop the Tomizawa Formation of the group according to the ammonite data. The present authors study the fossil spores and pollen newly found from the Tomizawa and Koyamada formations. Three assemblages have been recognized. They are Assemblage 1 （Cyathidites-Classopollis） from the upper part of the Tomizawa Formation, Assemblage 2 （Cyathidites-Jiaohepollis） from the lower part of the Koyamada Formation, and Assemblage 3 （Cyathidites-Spheripollenites-Ephedripites） from the middle to upper part of the Koyamada Formation. With the reference of ammonite evidence, the J-K boundary can be defined between Assemblage 1 and Assemblage 2. This palynological J-K boundary can be correlated with that of terrestrial sequence in China. However, local biostratigraphy imply that the continental J-K boundary in China is of 135 or 137 Ma age. It has a considerable discrepancy from the marine standard. Biogeographically, the distribution pattern of spores and pollen in southern China is in accordance with that in the Somanakamura group, which parallels the Tuchengzi Formation in northeastern China. By the palynological correlation between the Somanakamura group and the strata in southern China, and then with the sequence in northeastern China, it is suggested that th

关键词： Somanakamura group Jurassic-Cretaceous boundary ammonites spores and pollen,Tomizawa Formation Koyamada Formation Tuchengzi Formation

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Pc5 Oscillation Analysis by the Satellite and Ground-Based Data

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空间科学学报 2005年第5期25卷 393-396页

作者： A. Potapov T. Polyushkina T. L. Zhang H. Zhao A. Guglielmi J. Kultima Institute of Solar-terrestrial Physics Siberia Branch Russian Academy of Sciences Irkutsk 664033 Russia Space research Institute Austrian Academy of Sciences Graz Austria National Microwave Remote Sensing Laboratory Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 China Institute of Physics of the Earth Russian Academy of Sciences Moscow 123995 Russia Sodankylii Geophysical Observatory Sodankylii Finland

Large amplitude Pc5 event was observed in the space and on ground on August 3, 2001, about three hours after contact of the strong discontinuity in the solar wind with the magnetosphere according to data from ACE and Wind satellites. The Pc5 amplitude was as high as 15 nT in the tail of magnetosphere and about 5 nT at the ground based stations. In the magnetosphere Pc5 waves were observed by Cluster and Polar satellites, which occupied positions in the morning part of the near tail at the close field lines but were parted by distance of 11.5 Re, mainly along the x-axis of the GSM coordinate system. Both compressional and transverse components of the Pc5 wave activity were observed in the space, with the transverse component having the larger amplitude. Time delay between the Cluster and Polar satellites was about 8 minutes, which could be interpreted as a wave propagation from the geomagnetic tail to the Earth with the 150km/s group *** ground-based Pc5 activity was analysed by using data from the Image magnetometer network. Doubtless demonstrations of a field line resonant structure were found in variations of amplitude and polarization with latitude. Finnish chain of search coil magnetometers observed modulated Pc1 emission simultaneously with the Pc5 wave train. A possibility of non-linear impact of Pc5 wave energy on the plasma and waves in the magnetosphere is discussed.

关键词：人造卫星磁气圈太阳风太阳活动

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SMART COMMUNICATIONS AND NETWORKING FOR FUTURE DEEP-SPACE EXPLORATION

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China Communications 2020年第7期17卷 I0001-I0004页

作者： Qinyu Zhang Zhili Sun Tomaso de Cola Kanglian Zhao the EIE School the Institute for Communication Systems(ICS) Department of Electrical and Electronic EngineeringFaculty of Engineering and Physical SciencesUniversity of Surrey the German Aerospace Center(DLR) the Satellite and Space Communications(SSC)technical committee within ComSoc the Space-Internetworking Services(SIS)within the CCSDS standardization body the SatCom working group within the ETP Networld2020 platform School of Electronic Science and Engineering Nanjing University Institute of Space-terrestrial Intelligent Networks Nanjing University

Since the first space probe flew to the Moon in 1959,over 200 deep-space exploration missions have already been carried out on the eight planets,various asteroids and comets in the solar *** of deepspace scientific ex... 详细信息

关键词： SPACE planet NETWORK

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Skyline-Based Registration of 3D Laser Scans

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Geo-Spatial Information Science 2011年第2期14卷 85-90页

作者： Andreas Nüchter Stanislav Gutev Dorit Borrmann Jan Elseberg Automation group School of Engineering and Science Jacobs University Bremen gGmbH

Acquisition and registration of terrestrial 3D laser scans is a fundamental task in mapping and modeling of cities in three dimensions. To automate this task marker-flee registration methods are required. Based on the existence of skyline features, this paper proposes a novel method. The skyline features are extracted from panoramic 3D scans and encoded as strings enabling the use of string matching for merging the scans. Initial results of the proposed method in the old city center of Bremen are presented.

关键词： LIDAR point cloud processing 3D city modeling marker-free registration place recognition

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Halomethoxybenzenes in air of the Nordic region

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Environmental Science and Ecotechnology 2023年第1期13卷 57-63页

作者： Terry Bidleman Agneta Andersson Eva Brorstrom-Lunden Sonia Brugel Lars Ericson Katarina Hansson Mats Tysklind Department of Chemistry UmeåUniversity90187UmeåSweden Department of ecology&Environmental Science UmeåUniversity90187UmeåSweden UmeåMarine Science Centre UmeåUniversity90571HorneforsSweden IVL Swedish Environmental Research Institute(IVL)Aschebergsgatan 4441133GothenburgSweden

Halomethoxybenzenes(HMBs)are a group of compounds with natural and anthropogenic *** we extend a 2002e2015 survey of bromoanisoles(BAs)in the air and precipitation at Rå€o on the Swedish west coast and Pallas in Subarctic *** BAs data are reported for 2018 and 2019 and chlorinated HMBs are included for these and some previous years:drosophilin A methyl ether(DAME:1,2,4,5-tetrachloro-3,6-dimethoxybenzene),tetrachloroveratrole(TeCV:1,2,3,4-tetrachloro-5,6-dimethoxybenzene),and pentachloroanisole(PeCA).The order of abundance of HMBs at Råo was SBAs>DAME>TeCV>PeCA,whereas at Pallas the order of abundance was DAME>SBAs>TeCA>*** lower abundance of BAs at Pallas reflects its inland location,away from direct marine ***-Clapeyron(CC)plots of log partial pressure(Pair)/Pa versus 1/T suggested distant transport at both sites for PeCA and local exchange for DAME and *** were dominated by distant transport at Pallas and by both local and distant sources at Rå€*** between air and precipitation concentrations were examined by scavenging ratios,SR=(ng m^(-3))precip/(ng m^(-3))*** were higher at Pallas than Rå€o due to greater Henry's law partitioning of gaseous compounds into precipitation at colder *** is produced by terrestrial *** screened 19 fungal species from Swedish forests and found seven of them contained 0.01e3.8 mg DAME per kg fresh *** suggest that the volatilization of DAME from fungi and forest litter containing fungal mycelia may contribute to atmospheric levels at both sites.

关键词： Halomethoxybenzenes(HMBs) Bromoanisoles(BAs) Drosophilin A methyl ether(DAME) Tetrachloroveratrole(TeCV) Atmospheric transport Sources

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The organic geochemistry of crude oil in the Saltpond Basin(Ghana):Organic source input,depositional environment,and thermal maturity

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Acta Geochimica 2024年第3期43卷 424-440页

作者： Kojo Amoako Ningning Zhong Nancy Pearl Osei-Boakye Ebenezer Apesegah research group for Marine Geochemistry(ICBM-MPI Bridging group) Institute for Chemistry and Biology of the Marine Environment(ICBM)School of Mathematics and ScienceCarl von Ossietzky UniversitäOldenburgAmmerläder HeerstraВ114-11826129 OldenburgGermany State Key Laboratory of Petroleum Resources and Prospecting College of GeosciencesChina University of PetroleumBeijing 102249China Petroleum Corporation GNPCPMBPetroleum HouseTemaGhana

The Saltpond Basin,situated within the South Atlantic margin of Ghana,is a significant area for petro-leum exploration but has received relatively limited research *** studies have examined source rock com-position,but data on crude oil organic chemistry are lack-ing,hindering understanding of the basin’s petroleum system and *** address this gap,we analyzed biomarkers and stable carbon-isotope ratios in Saltpond Basin crude oil using gas chromatography–mass spectrometry and gas chromatography–isotope ratio mass spectrometry to eluci-date organic matter source,depositional environment,and thermal *** were compared with oils from the West African segment of the South Atlantic margin,namely the Tano Basin and the Niger Delta Basin,to iden-tify potential correlations and gain insights into regional *** and isotopic results unveiled a sig-nificant prevalence of organic matter derived from lower marine *** of organic matter deposition and preservation in Saltpond oil samples suggested a suboxic marine transitional environment,contradicting conventional understanding of terrestrial dominance in such ***,the potential for degradation processes to obscure differentiation between terrestrial and marine organic mat-ter origins underscores the complex nature of organic mat-ter dynamics in transitional marine *** of molecular thermal maturity indices suggested Saltpond oils were expelled from source rocks exhibiting thermal maturity at the early maturity *** analysis unveiled genetic disparities among crude oils sourced from the Saltpond Basin and those from the Tano and Niger Delta Basin,primarily due to variations in source input and depo-sitional environment *** oil exhibits lower terrestrial organic input than Tano Basin’s crude oils,which also have less terrestrial input than Niger Delta Basin crude ***,its paleodepositional envi

关键词： Biomarkers Carbon isotopes Crude oil Saltpond Basin Ghana

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Orchid diversity and distribution pattern in karst forests in eastern Yunnan Province,China

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Forest Ecosystems 2023年第3期10卷 348-356页

作者： Qiang Liu Xunfeng Wu Haitao Xing Kuanbo Chi Wenhua Wang Liang Song Xiaoke Xing Innovation group of Orchid Conservation and Utilization Yunnan Forestry Technological CollegeJindian RoadPanlong DistrictKunming650224China Jiuwuji Agricultural Service Center Luoping655804China CAS Key Laboratory of Tropical Forest ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesKunming650223China Institute of Medicinal Plant Development Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing100193China

Global biodiversity loss and mass extinction of species have raised serious global concerns,especially in fragile *** forest,a well-known fragile ecosystem,is served as a natural laboratory for biogeographical,ecological,evolutionary,and taxonomic ***,species richness and distribution patterns in karst forests largely remain *** has been regarded as the“flagship”group of plant *** this study,we use Wanfengshan Nature Reserve in southeast Yunnan,China,as a model to determine the conservation status of orchids in the karst forest by conducting systematic field surveys in the past three years from 2019 to *** total,we identified 78 orchid species in 35 genera in Wanfengshan Nature *** dominant species were Bulbophyllum andersonii,Eria coronaria,Nervilia mackinnonii and Paphiopedilum *** life forms were also observed,including epiphyte(14.29%),facultative epiphyte(18.18%),lithophyte(23.38%),and terrestrial(44.15%).Orchid species richness showed a bimodal pattern varied with altitude,the higher richness was recorded at 1,500-1,600 and 1,200-1,300 m,while the minimum was below 1,100 *** independent hill is rich in orchid species including‘endemic’species.A total of 25(33.8%)orchid species were considered threatened by the Redlist of Chinese Vascular Plants(Qin et al.,2017),including 3 CR species,5 EN species and 17 VU *** call for more research addressing the mechanisms of ecological adaption,mycorrhizal interactions,and pollination of orchids in karst forests,and effective ways for recovery and conservation of orchids.

关键词： Orchid diversity Limestone forest Resource investigation Threatened status Orchid conservation

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