Assessment of eco-environment vulnerability in the northeastern margin of the Qinghai-Tibetan Plateau,China

The northeastern margin of the Qinghai-Tibetan Plateau is typically a vulnerable eco-environment where an overload of alpine meadows and serious soil degeneration have led to vulnerability to natural disasters. Consequently, this vulnerable eco-environment does not allow for rapid socioeconomic development, resulting in weak potential for sustainable development. The northeastern margin of the Qinghai-Tibetan Plateau in China is used for this case study, which sets up 17 impact factors of eco-environment vulnerability (EEV) to assess the indexes, including natural impact factors, economic impact factors and social impact factors. Subsequently, the study uses an analytic hierarchy process to endow index weights and proposes an assessment model of ^n P_i W_i /( _i = 1^n P_i W_i + _i = 1^n P_i W_i ) G = 1 - \sum\nolimits_{i = 1}^{n} {{{P_{i} \cdot W_{i} } /{( {\max \sum\nolimits_{i = 1}^{n} {P_{i} \cdot W_{i} } + \min \sum\nolimits_{i = 1}^{n} {P_{i} \cdot W_{i} } } )}}} to analyze and assess the dynamic changes in the EEV of the study area from 1987–2008. Finally, the correlation of the EEV and 17 impact factors is analyzed.     

一个锢囚状中尺度对流系统的多尺度结构分析

利用多普勒雷达、气象卫星、自动气象站等监测资料、1°×1°NCEP再分析资料和4DVAR雷达反演低层风场资料,运用雷达拼图图形叠加、剖面和中尺度滤波等分析手段,对2007年7月18日华北东部一个锢囚状a中尺度对流系统(MaCS)的多尺度空间、动力结构及其演变进行了细致地分析.结果表明:(1) MaCS生命史分为发生发展...     

Distribution of intact and core GDGTs in marine sediments

We conducted a survey of archaeal GDGT (glycerol dibiphytanyl glycerol tetraether) distributions in marine sediments deposited in a range of depositional settings. The focus was comparison of two pools presumed to have distinct geobiological significance, i.e. intact polar GDGTs (IP GDGTs) and core GDGTs (C GDGTs). The former pool has been suggested to be related to living communities of benthic archaea in marine sediments, while the latter is commonly interpreted to consist of molecular fossils from past planktonic archaeal communities that inhabited the surface ocean. Understanding the link between these two pools is important for assessment of the validity of current molecular proxies for sedimentary archaeal biomass and past sea surface temperatures. The relative distributions of GDGTs in the two pools in a core at a CH₄ rich site in the Black Sea provide evidence for in situ production of glycosidic IP GDGTs and their subsequent degradation to corresponding C GDGTs on timescales that are short in geological terms. In addition, we monitored the relationship between the IP GDGT and C GDGT pools in a sample set from various ocean basins with subseafloor depth from a few cm to 320 m and 0 to 4 Myr in age. Notable differences between the two pools can be summarized as follows: the GDGT with acyclic biphytanes, GDGT-0, and its analogues with two and three cyclopentane moieties (GDGT-2 and -3) are generally more abundant in the pool of IP GDGTs, while crenarchaeol tends to be more abundant in the C GDGT pool. Consequently, the ring index is generally higher for the C GDGTs while TEX₈₆, a molecular proxy ratio not considering the two major GDGTs, tends to be higher in the IP GDGT pool. These differences in the proportion of individual GDGTs in the two pools are probably due to in situ production of IP GDGTs with distributions differing from those of C GDGTs. Despite these differences, we observed significant correlation of these two ratios between the two pools. Specifically, in both pools TEX₈₆ is high in sediments from warm oceanic regimes and low in cold regimes. We discuss these relationships and suggest that recycling of core GDGTs by benthic archaea is an important mechanism linking both molecular pools.     

Cloning and characterization of a delta-6 desaturase encoding gene from Nannochloropsis oculata

A gene(NANOC-D6D) encoding a desaturase that removes two hydrogen atoms from fatty acids at delta 6 position was isolated from a cDNA library of Nannochloropsis oculata(Droop) D.J.Hibberd(Eustigmatophyceae).The unicellular marine microalga N.oculata synthesizes rich long chain polyunsaturated fatty acids(LCPUFAs),including eicosapentaenoic acid(20:5n-3,EPA).The deduced protein contains 474 amino acids that fold into 4 trans-membrane domains.The neighbor-joining phylogenetic tree indicates that NANOC-D6D is ...     

Impacts of AMSU-A inter-sensor calibration and diurnal correction on satellite-derived linear and nonlinear decadal climate trends of atmospheric temperature

Climate Dynamics - Satellite microwave temperature sounding data have been widely used in the study of climate trends over the past decades. When merging advanced microwave sounding unit-A (AMSU-A)...     

中国典型地区人文-经济地理研究进展与展望

城市密集区、老工业基地、陆疆、山区是中国主要的地域类型,也是人文-经济地理学研究“人一地关系地域系统”形成规律、驱动力和作用机制、演化过程与空间格局的重要对象。伴随全球化、工业化、城市化、信息化的快速发展,不同地区的社会经济与自然系统之间的匹配和适应关系正发生着深刻而剧烈的变化,加强上述典型地区的研究既是人文一经济地理学科发展的内在要求,也是强化学科在国家和区域发展中的服务职能的必然要求。本文分析了中国城市密集区的空间格局及其演化,城市老工业区改造,边境城镇集聚扩散的动力机制,山区聚落空间、文化景观及其环境与山区资源环境承载力等方面的最新研究进展;总结了在国家重大地域空间规划和战略咨询中发挥的科技支撑作用以及在典型城市密集区可持续发展、老工业基地振兴、山区资源环境承载力等方面取得的重大研究成果和产生的社会影响。从学科建设和技术方法层面,提出未来要加强城市密集区发展的社会和生态效应,老工业基地振兴政策与绩效评价,陆疆地域系统演变机理和发展模式,应对气候变化的山区可持续生计选择、动力、机制等方面的研究。     

“天地图·黑龙江”网络安全态势感知解决方案

通过对"天地图·黑龙江"信息安全现状的分析,找出现有网络信息安全存在的问题,并提出相应解决方案,旨在解决网络信息安全系统管理形式分散、管理方式落后等方面问题,建造一个网络信息安全设备集中化、智能化管理的网络安全态势感知系统平台。     

历史时期伊犁河谷文化遗址时空特征及驱动力分析

运用Arc GIS软件对伊犁河谷文化遗址时空分布进行分析,探讨了遗址时空演变特征与人文历史、自然环境的关系。结果表明:1从夏—西周到清—近现代6个时期中,遗址数量及在总数中的比重、出现频率呈倒"V"型变化,从萌芽阶段到巅峰阶段,至衰落阶段。2遗址的空间分布格局由前3个时期的"东高西低"转变为后3个时期的"西高东低",人类活动空间重心发生了转移。3遗址主要分布在1~5级坡度上,其比重由春秋—秦时期的75%增至清—近现代时期的93.75%;而遗址集中分布高程则由春秋—秦和西汉—南北朝时期的4~8级转移到后3个时期的1~4级,且其数量表现出明显的从高海拔的山地丘陵向低海拔平原、从高坡度向低坡度转移。4研究区遗址演变模式与典型干旱区遗址迁移模式相反,表现为特殊的"中上游→下游"迁移的"湿润模式"。5研究区文化遗址分布、时空演变受政治、经济、生产力等人文因素和地貌、海拔、坡度、气候等自然因素的综合影响。由于其气候湿润,水资源丰富,虽然遗址分布和演变表现出一定的河谷谷地、阶地、平原、水资源等"自然因素"指向性规律,但更突出表现为生产力水平、政治稳定、经济发展、商贸交通等"人文力量"指向性规律,这一点在中后期表现得更为明显。