环渤海地区500年来的旱涝变化及其区域分异

用研究区１４７０～１９８５年的旱涝等级资料，划分了该地区５００年来旱涝变化的７个阶段，讨论了不同阶段间旱涝型的变化及其旱涝型区域分异意义。结果表明，５００年来研究区有４类主要旱涝型，各型旱涝在不同阶段的重要程度及场型特征有较大差异，深刻反映了该地区５００年来旱涝区域分异特征的变化。通过对５００年来旱涝变化与温度变化的对比发现，较温暖期，研究区的旱涝型及旱涝区域分异格局较多变，旱涝变化的区域差异性较     

资源型城市转型效率时空格局及影响因素探析：以陕甘宁能源富集区为例

基于数据包络分析、标准差椭圆和地理探测器方法，引入产业多样化指数和产业专业化指数，综合探讨陕甘宁资源型城市的转型效率、时空格局及其影响因素，得到2011—2020年陕甘宁资源型城市转型绩效综合得分及分布、不同发展阶段资源型城市转型绩效以及三省区各自资源型城市的转型绩效。结果表明：（1）2011—2020年陕甘宁资源型城市转型效率具有显著的时间和空间差异。（2）研究期内陕甘宁资源型城市转型效率空间分布格局基本保持稳定，仍以东西方向为主导。（3）地方财政一般预算内支出、城市建设用地面积、地区生产总值是影响资源型城市转型效率空间分异的主导因子。揭示了研究区资源型城市转型效率的发展演变态势及驱动因素，可为其持续优化转型提供决策依据。     

黑龙江省土地综合承载力空间差异研究

区域土地综合承载力研究为差别化土地利用政策的制定提供依据。本文根据土地综合承载力的内涵来构建评价指标体系,运用熵权法、多目标综合评价法及聚类分析法对黑龙江省土地综合承载力的空间差异进行研究。结果表明,黑龙江省土地综合承载力呈现出南高北低、西高东低的空间分异特征。通过障碍因素分析,表明:生态承载是高承载能力区和较高承载能力区(哈尔滨、大庆、齐齐哈尔、绥化)的主要障碍因素;经济承载是中等承载区(鸡西、伊春、佳木斯、牡丹江、黑河、大兴安岭)的主要障碍因素;水土资源承载是低承载能力区(鹤岗市、双鸭山和七台河)的主要障碍因素。在此基础上,针对不同土地综合承载区障碍因素特征提出了差别化土地利用政策。     

黄河流域县域经济密度测算及空间分异研究

县域经济是国民经济的基本单元,科学评估县域经济的空间分异、影响因素和形成机理,可以为区域经济分析和区域发展政策制定提供科学决策依据。本文以黄河流域504个县域为研究单元,采用熵权灰色模型、Jenks最佳分类法和Kernel分析等方法,基于人均、地均组成的经济密度综合指数构建经济密度评价指标体系和经济密度综合评价模型,从空间分布特征、空间集聚状态两个维度对2000年、2014年黄河流域县域经济密度的空间分异的特征状态和影响因素进行研究。研究结果表明:(1)流域经济密度的空间分异主要受人均密度系统影响,地均密度系统只是强化或减弱人均系统的分异强度。(2)黄河流域东部与中西部之间的经济密度差异明显。东部经济密度水平高,且形成了以郑州、济南为中心的高级别集聚状态,中东部以西安为中心形成了次一级集聚状态,而中西部经济密度整体水平低且仅有少量的弱集聚核心和集聚影响区。(3)流域中西部内部经济空间分异也发生变化。内蒙古、河南的经济密度水平较高,而其他省区的水平相对较弱;流域中西部高水平、中高水平经济密度区域及实力较强的集聚核心和扩展轴带分布在内蒙古中部、河南中部、陕西南部、山西中部,其他省区的集聚核心和扩展轴带较弱。     

Automatic sensitivity analysis of a finite volume model for two-dimensional shallow water flows

Given a numerical model for solving two-dimensional shallow water equations, we are interested in the robustness of the simulation by identifying the rate of change of the water depths and discharges with respect to a change in the bottom friction coefficients. Such a sensitivity analysis can be carried out by computing the corresponding derivatives. Automatic differentiation (AD) is an efficient numerical method, free of approximation errors, to evaluate derivatives of the objective function specified by the computer program, Rubar20 for example. In this paper AD software tool Tapenade is used to compute forward derivatives. Numerical tests were done to show the robustness of the model and to demonstrate the efficiency of these AD-derivatives.     

On the Laws and Causes of Socio-economic Territorial Differentiation in Minority Areas in China

Abstract

On the basis of applying quantitative and qualitative approaches as well as GIS technology, this paper established an index system to make a comprehensive evaluation on socioeconomic development of minority areas in China. The result showed that socio-economic development in minority area presents a series of characteristics that the north is high and the south is low, center-margin pattern is obvious and the areas with middle and lower development indices are distributed centrally and continuously. However, the causes of the socioeconomic characteristics mainly include natural conditions, economic development basic, population cultural quality, regional combination and development conditions of mineral and energy resources, informal institutional factors and distribution of major traffic lines.     

我国地方性氟中毒病区环境氟的安全阈值

概述了我国地方性氟中毒的4个流行区域及其环境特征,揭示地方性氟中毒的流行与地球化学环境密切相关,研究了不同氟中毒病区氟从外环境到人体的传输途径及其剂量-效应关系.选择氟斑牙检出率5%作为病区划分标准,确定了不同病区环境氟的安全阈值,为氟的环境风险评价提供科学依据.     

Genetic diversity and genetic differentiation of Squaliobarbus curriculus from the Pearl River based on mitochondrial D-loop sequences北大核心CSCD

Squaliobarbus curriculus is one of the most economically important edible freshwater fish in the Pearl River. To assess the level of genetic diversity and genetic variation of S. curriculus populations w ithin t he Pearl R iver, samples were collected from six geographical populations from six drainages. 978 base pairs of the D-loop sequence were obtained as a molecular marker. 106 haplotypes were defined among 170 S. curriculus individuals. Populations of S. curriculus in the Pearl River displayed a high haplotypic diversity index (h = 0.9820) and high nucleotide diversity index (π = 0.01353). T he results of genetic distance and genetic differentiation index show that genetic differentiation among S. curriculus populations is not significant. The neighbor-joining tree shows two clades. Clade A is composed of most haplotypes of S. curriculus. Clade B includes two private haplotypes from the Xijiang River. Haplotype network analysis is consistent with the results of genetic distance and genetic differentiation. The results of AMOVA analysis showed that most variation was found within populations (99.36%). Neutral test analysis explained that there was population expansion in the history of S. curriculus in the Pearl River. Xijiang River could be the center of origin, as supported by all the results. © 2018 Science Press. All rights reserved.     

贵州省旱地黄壤Zn和有机质的空间异质性特征

探究黄壤Zn和有机质的空间分布特征及其变异规律,分析环境因子对黄壤Zn和有机质空间分异的影响,对贵州省山地复杂环境下土壤资源的科学管理和可持续利用具有重要意义.基于130914个野外采样点,综合运用多种地统计学与传统统计学的方法,分析了贵州省旱地黄壤Zn和有机质的空间变异特征及其驱动因子.结果表明：①贵州省旱地黄壤Zn的平均含量略低于全国土壤Zn的平均含量（100 mg·kg^-1）,处于中等水平,而有机质含量则较为丰富;变异系数表明两者均属于中等程度的空间变异.②黄壤Zn和有机质均存在显著的空间自相关性,呈聚集分布,其中以Zn的Moran''s I指数更大、自相关程度更强;两个养分的最优理论模型均为指数模型,且块基比均介于25%~50%,具有中等程度的空间相关性,但结构性因素的作用更大;有机质的分形维数较Zn要高,其空间格局更复杂,对尺度的依赖性大.③Zn的高值区主要集中在西部和西北部地区,低值区多位于东南部和南部地区;有机质高值区沿西北东南带斜线分布,而低值区则沿东北西南方向与高值区呈现交叉分布的格局.④空间自相关分析和方差分析表明,选取的7个环境因子均对黄壤Zn和有机质的空间变异具有不同程度的影响,其中,高程和NDVI与两者的相关性更强.     

Genome Stability vs. Deprivation or Enrichment of the Geomagnetic Field

Summary This study suggested that cell-cycle kinetics, DNA replication and DNA repair react to magnetic fields differently. During their culture growth cycle, which lasted about five days, Friend erythroleukemia cells were either kept in the absence of magnetic fields in a magnetically shielded room or irradiated in a solenoid with 70 μT at 50 Hz plus 45 μT DC of the Earth: some cells grew without inducer of in vitro differentiation; others were induced to differentiate hemoglobin through dimethylsulfoxide. It emerged that, during a single culture growth cycle, while proliferation was slightly accelerated by the magnetic-field irradiation achieved in the solenoid both in undifferentiating and dimethylsulfoxide-differentiating cells, DNA replication did not appear to significantly depend on the magnetic-field deprivation achieved in the magnetically shielded room. However, as a result of a 318-day long magnetic-field irradiation in the solenoid, DNA replication remained unchanged in undifferentiating cells and partially inhibited in dimethylsulfoxide-differentiating cells. Following the same long magnetic-field irradiation in the solenoid, the amount of labelled repair patches in the parental DNA strands was slightly reduced.