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spatial-temporal dynamics of desert vegetation and its responses to climatic variations over the last three decades:a case study of Hexi region in Northwest China

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Journal of Arid Land 2016年第4期8卷 556-568页

作者： YANG Xuemei LIU Shizeng YANG Taibao XU Xianying KANG Caizhou TANG Jinnian WEI Huaidong Mihretab G GHEBREZGABHER LI Zhiqi State Key Laboratory Breeding Base of Desertification and Aeolian Sand Disaster Combating Gansu Desert Control Research Institute Institute of Glaciology and Ecogeography College of Earth and Environmental SciencesLanzhou University Eritrea Institute of Technology College of Education Wuwei Natural Protection Station the Management Bureau of Gansu Qilianshan National Nature Reserve

Analysis of spatial-temporal variations of desert vegetation under the background of climate changes can provide references for ecological restoration in arid and semi-arid areas. In this study, we used the Global Inventory Modeling and Mapping Studies （GIMMS） NDVI data from 1982 to 2006 and Moderate Resolution Imaging Spectroradiometer （MODIS） NDVI data from 2000 to 2013 to reveal the dynamics of desert vegetation in Hexi region of Northwest China over the past three decades. We also used the annual temperature and precipitation data acquired from the Chinese meteorological stations to analyze the response of desert vegetation to climatic variations. The average value of NDVImax （the maximum NDVI during the growing season） for desert vegetation in Hexi region increased at the rate of 0.65x10-3/a （P〈0.05） from 1982 to 2013, and the significant increases of NDVImax mainly appeared in the typical desert vegetation areas. Vegetation was significantly improved in the lower reaches of Shule and Shiyang river basins, and the weighted mean center of desert vegetation mainly shifted toward the lower reaches of the two basins. Almost 95.32% of the total desert vegetation area showed positive correlation between NDVImax and annual precipitation, indicating that precipitation is the key factor for desert vegetation growth in the entire study area. Moreover, the areas with non-significant positive correlation between NDVImax and annual precipitation mainly located in the lower reaches of Shiyang and Shule river basins, this may be due to human activities. Only 7.64% of the desert vegetation showed significant positive correlation between NDVImax and annual precipitation in the Shule River Basin （an extremely arid area）, indicating that precipitation is not the most important factor for vegetation growth in this basin, and further studies are needed to investigate the mechanism for this phenomenon.

关键词： desert vegetation NDVI global warming spatial-temporal variations Hexi region

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Land use dynamics in Lhasa area, Tibetan Plateau

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Journal of Geographical Sciences 2010年第6期20卷 899-912页

作者： CHU DUO ZHANG Yili BIANBA Ciren LIU Linshan Tibet Institute of Plateau Atmospheric and Environmental Sciences CMA Lhasa 850000 China Institute of Geographic Sciences and Natural Resources research CAS Beijing 100101 China

Land use change is the result of the interplay between socioeconomic, institutional and environmental factors, and has important impacts on the functioning of socioeconomic and environmental systems with important tradeoffs for sustainability, food security, biodiversity and the vulnerability of people and ecosystems to global change impacts. Based on the results of the First Land Use Survey in Tibet Autonomous Region carried out in the late 1980s land use map of Lhasa area in 1990 was compiled for the main agricultural area in Lhasa valley using aerial photos obtained in April, May and October 1991 and Landsat imagery in the late 1980s and 1991 as remotely sensed data sources. Using these remotely sensed data the land use status of Lhasa area in 1991, 1992, 1993, 1995, 1999 and 2000 were mapped through updating annual changes of cultivated land, artificial forest, grass planting, grassland restoration, and residential area and so on. Land use map for Lhasa area in 2007 was made using ALOS AVNIR-2 composite images acquired on October 24 and December 26, 2007 through updating changes of main land use types. According to land use status of Lhasa area in 1990, 1995, 2000 and 2007, the spatial and temporal land use dynamics in Lhasa area from 1990 to 2007 are further analyzed using GIS spatial models in this paper.

关键词： land use change Lhasa area Tibetan Plateau

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Standardization/Quantification of EEG-ERP Mapping and Source Imaging of Human Brain Function: Rapid Brain dynamics

Standardization/Quantification of EEG-ERP Mapping and Source...

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第一届全国脑与认知科学学术研讨会

作者： Andrew CN Chen center for Functional Human Brain Mapping Capital University of Medical Sciences Beijing China

＜正＞Mental function is uniquely characterised as sets of rapid brain dynamics, operating in a fraction of a second. Electromagnetic EEG-ERP mapping is much more effective than hemodynamic PET-fMRI neuroimaging in tracing the temporal processing of brain function. Though EEG and ERP have been used and tens of thousands of studies been reported over many decades, no standardised EEG measurement and quantification has been adopted in brain research and clinical use. This truly hampers the scientific vigour and progress in this field of human brain mapping. Previous qEEG mapping largely derived from BEAM is limited by merely a measure of power map from EEG electrode sites. No spatial

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Experimental digital quantum simulation of temporal–spatial dynamics of interacting fermion system

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Science Bulletin 2015年第2期60卷 241-248,I0002,I0003页

作者：陆遥冯冠儒李岩松龙桂鲁 State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua University Collaborative Innovation center of Quantum Matter Tsinghua National Laboratory for Information Science and Technology

Efficient simulations of many-body quantum systems are generally difficult on classical computers due to the exponential resource growth with the system size, while quantum computer has been proved to complete the same task effectively. In this article, we studied quantum algorithms for digital simulation of the dynamics of interacting quantum systems in real space. As an illustrative example, we concentrated on a digital quantum simulation algorithm for a two-fermion system with Coulomb interaction. We experimentally realized our algorithm on a three-qubit NMR device, and interesting phenomena such as the moving toward or against each other of particles under attractive or repulsive interaction have been clearly observed. This experiment demonstrated the very promising potential of quantum computers, even of small scale, to address the simulation of complex quantum systems.

关键词：多体量子系统相互作用系统费米子系统数字模拟时空动态实验量子计算机动态数字仿真

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Inverse Ising techniques to infer underlying mechanisms from data

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Chinese Physics B 2020年第8期29卷 1-23页

作者： Hong-Li Zeng Erik Aurell School of Science New Energy Technology Engineering Laboratory of Jiangsu ProvinceNanjing University of Posts and TelecommunicationsNanjing 210023China Nordita Royal Institute of Technologyand Stockholm UniversitySE-10691 StockholmSweden KTH-Royal Institute of Technology AlbaNova University CenterSE-10691 StockholmSweden Faculty of Physics Astronomy and Applied Computer ScienceJagiellonian University30-348 KrakowPoland

As a problem in data science the inverse Ising(or Potts)problem is to infer the parameters of a Gibbs-Boltzmann distributions of an Ising(or Potts)model from samples drawn from that *** algorithmic and computational interest stems from the fact that this inference task cannot be carried out efficiently by the maximum likelihood criterion,since the normalizing constant of the distribution(the partition function)cannot be calculated exactly and *** practical interest on the other hand flows from several outstanding applications,of which the most well known has been predicting spatial contacts in protein structures from tables of homologous protein *** applications to date have been to data that has been produced by a dynamical process which,as far as it is known,cannot be expected to satisfy detailed *** is therefore no a priori reason to expect the distribution to be of the Gibbs-Boltzmann type,and no a priori reason to expect that inverse Ising(or Potts)techniques should yield useful *** this review we discuss two types of problems where progress nevertheless can be *** find that depending on model parameters there are phases where,in fact,the distribution is close to Gibbs-Boltzmann distribution,a non-equilibrium nature of the under-lying dynamics *** also discuss the relation between inferred Ising model parameters and parameters of the underlying dynamics.

关键词： inverse Ising problem kinetic Ising model statistical genetics fitness reconstruction

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Probing electron and lattice dynamics by ultrafast electron microscopy: Principles and applications

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International Journal of Mechanical System dynamics 2023年第3期3卷 192-212页

作者： Yiling Lian Jingya Sun Lan Jiang Laser Micro/Nano Fabrication Laboratory School of Mechanical EngineeringBeijing Institute of TechnologyBeijingP.R.China Yangtze Delta Region Academy of Beijing Institute of Technology JiaxingP.R.China Chongqing Innovation center Beijing Institute of TechnologyChongqingP.R.China

Microscale charge and energy transfer is an ultrafast process that can determine the photoelectrochemical performance of ***,nonlinear and nonequilibrium properties hinder our understanding of ultrafast processes;thus,the direct imaging strategy has become an effective means to uncover ultrafast charge and energy transfer *** to diffraction limits of optical imaging,the obtained optical image has insufficient spatial ***,electron beam imaging combined with a pulse laser showing high spatial–temporal resolution has become a popular area of research,and numerous breakthroughs have been achieved in recent *** this review,we cover three typical ultrafast electron beam imaging techniques,namely,time-resolved photoemission electron microscopy,scanning ultrafast electron microscopy,and ultrafast transmission electron microscopy,in addition to the principles and characteristics of these three *** outstanding results related to photon–electron interactions,charge carrier transport and relaxation,electron–lattice coupling,and lattice oscillation are also *** summary,ultrafast electron beam imaging with high spatial–temporal resolution and multidimensional imaging abilities can promote the fundamental under-standing of physics,chemistry,and optics,as well as guide the development of advanced semiconductors and electronics.

关键词： ultrafast electron imaging charge transfer time-resolved photoemission electron microscopy scanning ultrafast electron microscopy ultrafast transmission electron microscopy

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The bacterial abundance and production in the East China Sea: seasonal variations and relationships with the phytoplankton biomass and production

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Acta Oceanologica Sinica 2014年第9期33卷 166-177页

作者： CHEN Bingzhang HUANG Bangqin XIE Yuyuan GUO Cui SONG Shuqun LI Hongbo LIU Hongbin Fujian Provincial Joint Key Laboratory of Coastal Ecology and Environmental Studies and State Key Laboratory of Marine Environmental Science Xiamen University Division of Life Science Hong Kong University of Science and Technology Key Laboratory of Marine Ecology and Environmental Science Institute of Oceanology Chinese Academy of Sciences National Marine Environmental Monitoring center State Oceanic Administration

The East China Sea is a productive marginal sea with a wide continental shelf and plays an important role in absorbing atmospheric carbon dioxide and transferring terrigenous organic matter to the open ocean. To investigate the roles of heterotrophic bacteria in the biogeochemical dynamics in the East China Sea, bacterial biomasses （BB） and productions （BP） were measured in four cruises. The spatial distributions of the BB and the BP were highly season-dependent. Affected by the Changjiang River discharge, the BB and the BP were high in shelf waters （bottom depth not deeper than 50 m） and generally decreased offshore in August 2009. In December 2009 to lanuary 2010, and November to December 2010, the BB and the BP were high in waters with medium bottom depth. The onshore-offshore decreasing trends of the BB and the BP also existed in May-June 2011, when the BB was significantly higher than in other cruises in shelf break waters （bottom depth deeper than 50 m but not deeper than 200 m）. The results of generalized additive models （GAM） suggest that the BB increased with the temperature at a range of 8-20~C, increased with the chlorophyll concentration at a range of 0.02-3.00 mg/m3 and then declining, and decreased with the salinity from 28 to 35. The relationship between the temperature and the log-transformed bacterial specific growth rate （SGR） was linear. The estimated temperature coefficient （Q10） of the SGR was similar with that of the phytoplankton growth. The SGR also increased with the chlorophyll concentration. The ratio of the bacterial to phytoplankton production ranged from less than 0.01 to 0.40, being significantly higher in November December 2010 than in May-June 2011. Calculated from the bacterial production and growth efficiency, the bacterial respiration consumed, on average, 59%, 72% and 23% of the primary production in August 2009, November-December 2010, and May-/une 2011, respectively.

关键词： bacterial production generalized additive model chlorophyll temperature East China Sea

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Correlation of the temporal and spatial expression patterns of HQT with the biosynthesis and accumulation of chlorogenic acid in Lonicera japonica flowers

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Horticulture research 2019年第1期6卷 934-947页

作者： Yanqun Li Dexin Kong Mei Bai Hanjun He Haiyang Wang Hong Wu State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources South China Agricultural UniversityGuangzhou 510642China Guangdong Technology research center for Traditional Chinese Veterinary Medicine and Natural Medicine South China Agricultural UniversityGuangzhou 510642China Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm South China Agricultural UniversityGuangzhou 510642China

Hydroxycinnamoyl-CoA quinate transferase(HQT)is one of the key enzymes in the biosynthesis of chlorogenic acid(CGA)in the flowers of Lonicera ***,the spatiotemporal expression patterns of HQT and its relationship to the dynamics of CGA biosynthesis,transport,and storage remain largely *** this study,we collected *** flower samples at different growth stages(S1–S6)and examined the spatiotemporal expression pattern of HQT and the dynamic accumulation patterns of CGA using a combination of molecular and cytological *** results suggest that the spatiotemporal expression pattern of HQT is directly correlated with dynamic changes in CGA accumulation and distribution in *** *** further show that CGA is synthesized primarily in the cytoplasm and *** synthesized in the cytoplasm first accumulates in specialized vesicles and is then transferred to large central vacuoles for storage by fusion of CGA-containing vesicles with ***,CGA synthesized in the chloroplasts appears to be transferred into the vacuoles for storage by direct membrane fusion between the tonoplast and the disrupted chloroplast ***,our results suggest that CGA is synthesized in chloroplasts and cytoplasm and finally transferred to the vacuole for long-term storage.

关键词： flowers transferred specialized

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dynamics of synthetic yeast chromosome evolution shaped by hierarchical chromatin organization

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National Science Review 2023年第5期10卷 240-250页

作者： Sijie Zhou Yi Wu Yu Zhao Zhen Zhang Limin Jiang Lin Liu Yan Zhang Jijun Tang Ying-Jin Yuan Frontiers Science center for Synthetic Biology (Ministry of Education) Tianjin University Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin University Institute for Systems Genetics NYU Langone Health School of Computer Science and Technology College of Intelligence and ComputingTianjin University Epigenetic Group Frasergen Bioinformatics Co.Ltd. Department of Computer Science University of South Carolina

Synthetic genome evolution provides a dynamic approach for systematically and straightforwardly exploring evolutionary *** Chromosome Rearrangement and Modification by LoxP-mediated Evolution(SCRaMbLE) is an evolutionary system intrinsic to the synthetic yeast genome that can rapidly drive structural ***,we detect over 260 000 rearrangement events after the SCRaMbLEing of a yeast strain harboring 5.5 synthetic yeast chromosomes(synⅡ,synⅢ,synⅤ,circular synⅥ,synⅨR and synⅩ).Remarkably,we find that the rearrangement events exhibit a specific landscape of *** further reveal that the landscape is shaped by the combined effects of chromatin accessibili and spatial contact *** rearrangements tend to occur in 3D spatially proximal and chromatin-accessible *** enormous numbers of rearrangements mediated by SCRaMbLE provide a driving force to potentiate directed genome evolution,and the investigation of the rearrangement landscape offers mechanistic insights into the dynamics of genome evolution.

关键词： synthetic biology genome rearrangement hierarchical chromatin organization synthetic yeast genome SCRaMbLE Saccharomyces cerevisiae

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Transmission-reflection optoacoustic ultrasound(TROPUS)computed tomography of small animals

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Light(Science & Applications) 2019年第1期8卷 1051-1062页

作者： Elena Mercep Joaquin LHerraiz Xose Luis Dean-Ben Daniel Razansky Faculty of Medicine Technical University of MunichMunichGermany iThera Medical GmbH MunichGermany Nuclear Physics Group and UPARCOS Complutense University of MadridCEI MoncloaMadridSpain Health research Institute of Hospital Clinico San Carlos(IdISSC) MadridSpain Institute for Biological and Medical Imaging(IBMI) Helmholtz Center MunichNeuherbergGermany Faculty of Medicine and Institute of Pharmacology and Toxicology University of ZurichZurichSwitzerland Institute for Biomedical Engineering and Department of Information Technology and Electrical Engineering ETH ZurichZurichSwitzerland

Rapid progress in the development of multispectral optoacoustic tomography techniques has enabled unprecedented insights into biological dynamics and molecular processes in vivo and noninvasively at penetration and spatiotemporal scales not covered by modern optical microscopy *** imaging provides highly complementary information on elastic and functional tissue properties and further aids in enhancing optoacoustic image *** devised the first hybrid transmission–reflection optoacoustic ultrasound(TROPUS)small animal imaging platform that combines optoacoustic tomography with both reflection-and transmission-mode ultrasound computed *** system features full-view cross-sectional tomographic imaging geometry for concomitant noninvasive mapping of the absorbed optical energy,acoustic reflectivity,speed of sound,and acoustic attenuation in whole live mice with submillimeter resolution and unrivaled image ***-processing unit(GPU)-based algorithms employing spatial compounding and bent-ray-tracing iterative reconstruction were further developed to attain real-time rendering of ultrasound tomography images in the full-ring acquisition *** vivo mouse imaging experiments revealed fine details on the organ parenchyma,vascularization,tissue reflectivity,density,and *** further used the speed of sound maps retrieved by the transmission ultrasound tomography to improve optoacoustic reconstructions via two-compartment *** newly developed synergistic multimodal combination offers unmatched capabilities for imaging multiple tissue properties and biomarkers with high resolution,penetration,and contrast.

关键词： reflectivity rendering details

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