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Seed dormancy and germination characteristics of two Rheum species in the Himalaya-Hengduan Mountains

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植物多样性：英文版 2017年第4期39卷 180-186页

作者： Deli Peng Zhe Chen Xiaojian Hu Zhimin Li bo Song Hang Sun Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of Botany Chinese Academy of Sciences Kunming 650201 Yunnan China School of Life Science Yunnan Normal University Kunming 650500 Yunnan China Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Kunming 650201 Yunnan China University of Chinese Academy of Sciences Belting 100049 China

Seed dormancy and germination characteristics are important factors determining plant reproductive success, and may be expected to have a major influence on plant distribution. In this study, we aimed to explore the characteristics of seed dormancy and germination in two endemic Rheum species(Rheum nobile and Rheum alexandrae) in the Himalaya-Hengduan Mountains. To determine the type of dormancy,fresh seeds of the two species(one population each) were incubated in light at 25/15 and 15/5℃, and then dry after-ripening(dar) seeds were incubated on water agar substrate with or without GA_3. To determine the effect of temperature and light on germination, dar seeds of the two species(two populations each) were incubated both in the light and in the dark at several temperatures, including constant and alternating temperatures. Base temperature(T_b) and thermal times for 50% germination(θ_(50)) were calculated. dar released physiological dormancy(PD), increasing final germination at 15/5℃ and widening the range of germination temperatures from higher to lower, indicative of type 2 non-deep PD for the two Rheum species. Light had no significant effect on germination of seeds from the two species(two populations each). Seeds of the two species germinated significantly better(>80%) at medium temperatures(10-25℃) than at extreme low(5℃) or high(35℃) temperatures. Alternating temperatures(25/15 and 15/5℃) did not significantly increase the final germination of the two species either in the light and in the dark, but it promoted seed germination more quickly than corresponding constant temperatures in the light in both Rh. alexandrae populations, especially at 15/5℃. Germination in response to temperature was well described by the thermal-time model at suboptimal temperatures. The estimated Tbvalues were 1 and 0.9℃, respectively, in two Rh. nobile populations; 4 and 4.1℃,respectively, in two Rh. alexandrae populations; θ_(50)(thermal time) were 100 and 125℃d, respectively in tw

关键词： Germination Light Rheum alexandrae Rheum nobile Dormancy Temperature

Vegetation dynamics in response to human and climatic factors in the Tanzanian Coast

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Frontiers of Earth Science 2021年第3期15卷 595-605页

作者： Herrieth MACHIWA bo TIAN Dhritiraj SENGUPTA Qian CHEN Michael MEADOWS Yunxuan ZHOU State Key Laboratory of Estuarine and Coastal Research East China Normal UniversityShanghai 200241China University of dar es Salaam College of Information and Communication TechnologiesDepartment of Computer Science and EngineeringDar es Salaam 33335Tanzania Key Laboratory of Geographic Information Science(Ministry of Education) School of Geographical SciencesEast China Normal UniversityShanghai 200241China Department of Environmental&Geographical Sciences University of Cape TownRondebosch 7701South Africa College of Geography and Environmental Sciences Zhejiang Normal UniversityJinhua 321004China

This study of vegetation dynamics in the coastal region of Tanzania provides a fundamental basis to better understand the nature of the factors that underlie observed *** Tanzanian coast,rich in biodiversity,is economically and environmentally important although the understanding of the nature and causes of vegetation change is very *** paper presents an investigation of the relationship between vegetation dynamics in response to climate variations and human activities using Moderate Resolution Imaging Spectro-radiometer(MODIS),Normalized Difference Vegetation Index(NDVI),meteorological,and Globeland30 Landsat data ***-temporal trends and the relationship of NDVI to selected meteorological variables were statistically analyzed for the period 2000-2018 using the Mann-Kendall test and Pearson correlation *** results reveal a significant positive trend in temperature(/?>0,Z=2.87)and a non-significant trend in precipitation(|Z|<1.96).A positive relationship between NDVI and precipitation is *** Tanzania has therefore experienced increased temperatures and variable moisture conditions which threaten natural vegetation and ecosystems at *** land cover maps obtained from GlobeLand30 were analyzed to identify the nature and scale of human impact on the *** analysis of land use and land cover in the region reveals an increase in cultivated land,shrubland,grassland,built-up land and bare land,while forests,wetland and water all decreased between 2000 and *** decrease in forest vegetation is attributable to the fact that most livelihoods in the region are dependent on agriculture and harvesting of forest products(firewood,timber,charcoal).The findings of this study highlight the need for appropriate land-use planning and sustainable utilization of forest resources.

关键词： remote sensing NDVI climate variations spatio-temporal changes LULCC coastal Tanzania

Computation of the atmosphere-less light intensity curve during a total solar eclipse by using Lunar Reconnaissance Orbiter topography data and the DE430 astronomical ephemeris

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Research in Astronomy and Astrophysics 2021年第1期21卷 105-118页

作者： Yun-bo Wang Jian-Guo Yan Mao Ye Yong-Zhang Yang Fei Li Jean-Pierre Barriot State Key Laboratory of InformationEngineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Geodesy Observatory of Tahiti University of French PolynesiaBP 657098702 FaaTahitiFrench Polynesia Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

Observations of the sky irradiation intensity in the visible wavelengths during a solar eclipse permit to model the Sun diameter,a key number to constrain the internal structure of our *** this paper,we present an algorithm that takes advantage of the precise Moon topography from Lunar Reconnaissance Orbiter to compute,with a high resolution in time,the geometrical part(***-of-atmosphere,and for a given wavelength)of the sky irradiation at any given location on the Earth during these *** algorithm is also able to model the Baily’s *** give as an application the theoretical computation of the light curve corresponding to the solar eclipse observed at Lakeland(Queensland,North Australia)on 2012 November *** application to real data,with the introduction of atmospheric and instrumental passbands,will be considered in a forthcoming paper.

关键词： eclipse Moon Sun:fundamental parameters

A CORBA-Based Multidatabase System——Panorama Project

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Wuhan University Journal of Natural Sciences 2003年第1A期8卷 21-27页

作者： Lou Qin\|jian, Sarem Mu dar, Li Rui\|xuan, Xiao Wei\|jun, Lu Zheng\|ding, Chen Chuan\|bo School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 Hubei China

Panorama is a multidatabase system (MDBS) devel oped in HUST. The project aims to achieve interoperability among existing, heter ogeneous, federated database management systems such as Oracle8, Sybase, and DM2 (A database management system developed at HUST, Wuhan, China). This system is based on OMG's distributed object management architecture and it is implemented on top of CORBA compliant, namely VisiBroker, which is used as its infrastructu re. Panorama can provide its users a single common data model and a single globa l query language named PanoSQL, which make it possible to incorporate different databases into the system. The main component of this system are interfaces for the Local DBMSs that participate in Panorama, a transaction manager, a common da ta model, a schema integrator, a global query language, and a global query proce ssing and optimization. We first discuss the architecture and components of Panorama system. We also dis cuss the schema integration in this system. And we extend our discussion to the query language, transaction management, and the query processing developed for t his system. Finally, a conclusion and the future work for our designed system ha ve been given.

关键词： heterogeneity CORBA architecture interoperabil ity schema integration multidatabase system

Simulated Gravity Field Estimation for the Main Belt Comet 133P/Elst-Pizarro Based on a Satellite-to-satellite Tracking Mode

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天文和天体物理学研究:英文版 2023年第9期23卷 129-141页

作者： Shang-Biao Sun Jian-Guo Yan Wu-Tong Gao bo Wang Zhen Wang Mao Ye Jean-Pierre Barriot State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Geodesy Observatory of Tahiti University of French PolynesiaBP 6570F-98702 FaaaTahitiFrench PolynesiaFrance

Most asteroids and comets are formed in the early stages of the solar system and therefore contain a wealth of information about their *** asteroid exploration mission planned in the coming years by China will likely target the celestial body named 133P/Elst-Pizarro(estimated diameter of about 4 km).The orbit of this asteroid stays within the asteroid belt,but nevertheless,it displays a comet-like dust *** this study,we used differential tracking data between two simulated probes and the data from an Earth station to estimate 133P gravity field *** observation mode is similar to how the gravity field was estimated for large celestial objects in the GRAIL and GRACE missions,but here the object is the very small 133P *** compared the estimated gravity fields obtained for 133P from the satellite-to-satellite combined with the Earth-based two-way range-rate observation mode,with only the Earth-based two-way range rate *** results show that the accuracy of the low-degree(4 degree and order)estimate of the gravity field is improved by one order of magnitude by using the satellite-to-satellite combined with the Earth-based two-way range-rate observation mode with respect to the Earthonly ***,another order of magnitude improvement in the gravity field solution is gained by decreasing the orbit altitude from 12 to 8 km.

关键词： gravitation-methods data analysis-celestial mechanics-comets general

试论古格时期藏传佛教诸教派在阿里地区的弘传与纷争

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四川师范大学学报(社会科学版) 2012年第1期39卷 161-167页

作者：黄博四川大学中国藏学研究所

藏传佛教后弘期之初,在古格王室的大力扶持下,佛教从上部阿里地区开始弘传,阿里地区一度居于全藏宗教文化的领先地位。同时,后弘期前期也是西藏佛教发展史上一个极具活力的时代,宗派竞起,精彩纷呈。在这一过程中,卫藏地区后来居上,各教... 详细信息

藏传佛教后弘期之初,在古格王室的大力扶持下,佛教从上部阿里地区开始弘传,阿里地区一度居于全藏宗教文化的领先地位。同时,后弘期前期也是西藏佛教发展史上一个极具活力的时代,宗派竞起,精彩纷呈。在这一过程中,卫藏地区后来居上,各教派在卫藏地区相继创立,并传入上部阿里地区。其中,止贡噶举派成就特别突出,得到西藏西部的古格、普兰、拉达克等地方政权的支持,成为阿里地区主导教派。15世纪初,格鲁派在卫藏地区兴起并迅速传入阿里,得到古格政权的大力扶持,成为古格境内的主导教派;另一方面,拉达克政权则开始转而成为主巴噶举派的信徒,双方在宗教派别的信奉上渐生分歧,格鲁派与主巴噶举派的矛盾日益增加,以致双方冲突不断,直至古格政权崩溃。

关键词：藏传佛教阿里噶举派格鲁派

影像辅助下基于地面Lidar的建筑物特征精细提取方法

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应用基础与工程科学学报 2015年第2期23卷 299-307页

作者：杨林盛业华王波南京师范大学虚拟地理环境教育部重点实验室江苏南京210023 江苏省地理信息资源开发与利用协同创新中心江苏南京210023

面向建筑物精细建模,探讨了在影像辅助下基于地面Li dar的建筑物几何特征精细提取方法.首先在基于梯度方向进行建筑物特征初步提取的基础上,引入建筑结构完整性约束规则,进行了特征边缘线段合并与角点处特征线的闭合处理.然后利用影像与... 详细信息

面向建筑物精细建模,探讨了在影像辅助下基于地面Li dar的建筑物几何特征精细提取方法.首先在基于梯度方向进行建筑物特征初步提取的基础上,引入建筑结构完整性约束规则,进行了特征边缘线段合并与角点处特征线的闭合处理.然后利用影像与Li dar点云配准关系将建筑物影像特征线映射到三维点云空间,即获得影像三维空间坐标.在此辅助下,最后通过估算点云法向、曲率,得到精细的几何特征,从而更好地表达地理场景中的建筑物.研究实例表明,本文的特征提取方法严谨可靠,能有效提高点云特征提取的效率和精度.

关键词：地面Lidar 影像建筑物建模特征提取

基于改进彗星星历的67P/Churyumov-Gerasimenko的三阶重力场模型

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中国科学：物理学、力学、天文学 2023年第5期53卷 135-149页

作者：高梧桐鄢建国王波杨婉羚李斐 Jean-Pierre Barriot 武汉大学测绘遥感信息工程国家重点实验室武汉430079 Geodesy Observatory of Tahiti University of French PolynesiaFaa’a Tahiti F-98702French Polynesia

本文解算了Rosetta彗星探测任务的主要目标——彗星67P/Churyumov-Gerasimenko的重力场模型.与以往模型的主要区别是,本文使用了JPL团队最新解算的67P星历模型,该彗星星历在很大程度上得到了改进.67P的改进星历能够对其GM值的解算产生... 详细信息

本文解算了Rosetta彗星探测任务的主要目标——彗星67P/Churyumov-Gerasimenko的重力场模型.与以往模型的主要区别是,本文使用了JPL团队最新解算的67P星历模型,该彗星星历在很大程度上得到了改进.67P的改进星历能够对其GM值的解算产生一定的影响,这一影响与67P通过近日点由于彗星喷发造成的质量损失处于同一水平.新的彗星重力场解算结果表明,67P重力异常比过去的模型更加显著.从2.65 km的参考球上看,新的重力场模型最大重力异常值约为0.9±0.03 mGal,较大的异常值表明了该彗星内部质量分布不均一的特性,这可能是由于高孔隙率和分层的彗核结构导致的.

关键词： 67P/Churyumov-Gerasimenko 重力场彗星精密定轨内部结构

基于机载Lidar数据的城市建筑物高度分级方法研究

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测绘通报 2015年第4期 82-85页

作者：黄明张锦曾波太原理工大学测绘科学与技术系山西太原030024 山西省测绘工程院山西太原030024

传统的基于不规则的三角网和形态学点云滤波处理方法提取的DEM,由于在滤波过程中没有顾及不同区域地形起伏度差异,使得滤波过程中产生大量粗差,导致DEM与实际地形偏差太大。准确提取建筑物轮廓和高程的前提是要提取高精度的DEM,因此必须... 详细信息

传统的基于不规则的三角网和形态学点云滤波处理方法提取的DEM,由于在滤波过程中没有顾及不同区域地形起伏度差异,使得滤波过程中产生大量粗差,导致DEM与实际地形偏差太大。准确提取建筑物轮廓和高程的前提是要提取高精度的DEM,因此必须在DSM转化为DEM的过程中改进DEM提取方法。本文针对地形起伏度不大的城市区域,采取格网值替换、设置高程和面积阈值进行过滤处理的方法提取建筑物轮廓及高程值,验证表明该提取方法的精度优于传统滤波方法。

关键词： DEM DSM 高程阈值面积阈值