Assessing effects of “source-sink” landscape on non-point source pollution based on cell units of a small agricultural catchment

Ascertaining the relationship between "source-sink" landscape and non-point source(NPS) pollution is crucial for reducing NPS pollution, however, it is not easy to realize this target on cell unit scale. To reveal the relationships between "sourcesink" landscape and NPS pollution based on cell units of a small catchment in the Three Gorges Reservoir Region(TGRR), the runoff and nutrient yields were simulated first by rainfall events on a cell unit scale based on the Annualized AGricultural Non-Point Source Pollution Model(AnnAGNPS). Landscape structure and pattern were quantified with "sourcesink" landscape indicators based on cell units including landscape area indices and locationweighted landscape indices. The results showed that:the study case of small Wangjiagou catchment highlighted a good prediction capability of runoff and nutrient export by the AnnAGNPS model. Throughout the catchment, the spatial distribution trends of four location-weighted landscape indices were similar to the trends of simulated total nitrogen(TN) and total phosphorus(TP), which highlighted the importance of spatial arrangement of "source" and "sink" landscape types in a catchment when estimating pollutant loads. Results by Pearson correlation analysis indicated that the location-weighted landscape index provided a more comprehensive account of multiple factors, and can better reflect NPS-related nutrient loss than other landscape indices applied in single-factor analysis. This study provides new findings for applying the "source-sink" landscape indices based on cell units in small catchments to explain the effect of "source-sink" landscape on nutrient export based on cell unit, and helps improve the understanding of the correlation between "source-sink" landscape and NPS pollution.     

基于拓扑关系的BIM室内封闭空间边界建筑要素搜索方法研究

BIM作为工程建设领域的热门新兴技术,包含建筑物全生命周期内的各种数字化信息,但其对要素间空间关系的描述限于建筑领域的专业性表达,以及建模过程中的预定义。基于BIM数据的几何-语义特点,提出一种自动化构建BIM建筑要素拓扑关系的方法,并以此为基础搜索室内封闭空间的边界建筑要素,得到以建筑要素为单元的室内空间划分;以整层建筑物空间作为实验数据,通过实验结果验证了算法的准确性,实现BIM室内三维空间分割,为基于BIM的空间分析提供数据支撑。     

鄂尔多斯盆地前寒武纪末期古地貌恢复及其对烃源岩的控制作用

鄂尔多斯盆地前寒武纪末期古地貌控制着后期沉积体系的空间配置与古地理展布。通过野外剖面、岩芯分析、测井数据等建立鄂尔多斯盆地寒武系层序地层格架;选取寒武纪SS1最大海泛面(徐庄组沉积晚期地层)为标志层,通过残余厚度印模法,并结合古地质图分析,对研究区前寒武纪进行古地貌恢复,明确了前寒武纪沉积背景、构造格局及物源方向。总体上,前寒武纪鄂尔多斯盆地南、北濒临秦祁海和兴蒙海,东、西被贺兰和晋豫陕坳拉槽所夹持,古地貌东北高、西南低,受秦祁海影响最大,可将其划分为3个古构造地貌单元:高地剥蚀区、受古构造控制形成的坳陷区以及处于剥蚀与沉积过渡地带的斜坡阶地区。通过研究前寒武纪末期古地貌与寒武纪早期烃源岩分布认为,拉张活动背景下的坳陷带以及斜坡带是鄂尔多斯盆地寒武纪早期烃源岩发育的有利区块,前寒武纪古地貌格局影响了寒武纪早期烃源岩发育与分布。恢复古地貌形态对于揭示物源供给,研究沉积物搬运、平面和纵向展布特征,探究沉积、沉降中心的迁移规律,以及进一步揭示生储盖组合和分布具有重大意义。     

内含裂隙角的恐龙化石轴向受压数值试验及裂纹扩展机理研究

面临众多古生物化石遭受风化破坏的现实,恐龙化石保护是一项世界性难题。化石的风化原因多种多样,其中化石内部裂隙是导致恐龙化石风化、破坏的重要因素。该文以岩石断裂力学为理论依据,模拟分析内含裂隙的恐龙化石在压力作用下的破坏情况。通过数值模拟的方法,进行了内含裂隙恐龙化石数值压缩试验,并对内含裂隙的恐龙化石裂纹扩展机理进行了研究。研究结果表明,随着裂隙角度增大,开裂角逐渐减小,裂隙处特别是两端应力集中,其他部位应力较低、分布均匀;裂纹扩展是从裂纹尖端起裂,最终裂纹扩展到边缘。此研究结果为揭示恐龙化石风化机理和开展保护提供了基础参考资料。     

基于不同区域层级的文化产业集聚研究

利用企业层面数据,从市域和省域两个尺度研究中国文化产业的集聚特征,并揭示集聚对文化企业生产率的影响。应用一致性方法估计了中国文化企业的生产函数,并计算企业层面全要素生产率估计值,并从专业化和城市化两个角度研究集聚对于文化企业的影响。结果表明：① 地级市尺度下,文化产业专业化经济并不显著,但却存在城市化经济;② 在更大的省域层面,则呈现出专业化经济显著,多样化经济弱化的特征;③ 行业和区域异质性回归显示了结果的稳健性,核心文化产业的产业集聚经济更显著;④ 在知识溢出效应占主导的文化集聚中,通信基础设施良好的省份被赋予了创意交流的便利性,因而拥有更强的集聚经济。     

基于手机数据的城市公共空间活力评价方法研究——以南京市公园为例

针对已有公共空间活力评价方法存在视角单一,对活力多样性体现不足的问题,本文在深入理解活力内涵与特征的基础上,探讨了多维视角下的公共空间活力评价方法。从个体行为、空间活动、空间交互联系网络的复合视角,围绕活力的核心,综合考虑活动类型及空间联系,提出了重访性、混合性、网络交互中心性三项测度评价指标,在此基础上构建了公共空间活力评价方法框架。以南京市公园为例,采用手机大数据,进行了公园活力的综合评价。分析表明：手机数据可从多个维度快速准确的识别城市公共空间活力现状,并展开综合评价。同时,可进一步参照活力不同维度特征的测度结果,提出具有针对性的活力营造及提升策略与路径指导,体现了本方法对已有评价方法具有一定修正和延展作用。     

Spatiotemporal distribution of fish eggs and larvae in the Huanghe(Yellow) River estuary,China in 2005–2016

Decreasing fish resources in estuaries is a subject of anthropogenic activities.Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in a fishery.As the fifth largest river estuary in the world,the Huanghe(Yellow)River estuary(HRE)is a typical estuary that has been seriously affected by human activities.Annual surveys on ichthyoplankton and environmental factors were conducted in the months of May of 2005 and 2009-2016 in the HRE to investigate the spatiotemporal distribution of fish eggs and larvae and the associated influencing factors.A total of 23 and 20 species of eggs and larvae,respectively,were collected.The dominant orders were Perciformes(51.2%)and Clupeiformes(25.6%).The average number of fish species eggs and larvae were 6.0 and 4.1 in average abundance of 0.91 and 0.13 ind./m~3,respectively.The dominant species were mainly low-commercial-value small-sized fishes,such as Clupanodon punctatus,Hare,ngula zutnasi,and Acanthogobius,whereas certain traditional commercial fishes,such as Trichiurus lepturus,and Clupea pallasii,were not seen.Analysis of the fish egg and larval community revealed four temporal assemblages and two spatial assemblages.Salinity was the main factor on the spatial distribution of ichthyoplankton communities,the species number and Shannon-Weiner diversity index(H')of the fish egg and larval community near the river mouth with lower salinity were significantly lower than the community far away from the river mouth with higher salinity.In addition,increases of water temperature promoted the number and abundance of fish species eggs,and the areas of abundant prey tended to have a more diversified and abundant of ichthyoplankton species.In overall,overfishing,dam construction,and other human activities were the main drivers that led to the substantial decline in fishery resources in the HRE.     

Effect of diet on the development,survival, and reproduction of the calanoid copepod Pseudodiaptomus dubia

Pseudodiapto,mus dubia is a calanoid copepod abundant in the mariculture ponds of southern China.However,our understanding of the population dynamics of P.dubia in aquaculture ponds is limited.In this study,groups of larval P.dubia were each fed a different microalgal species,and the effects of these different diets on development,survival,and reproduction were assessed.The five microalgae used were species common in aquaculture farms in China,and included two chlorophytes(Chlorella saccharophila and Platymonas subcordiformis),one golden microalga(Isochrysis zhan.jiangensis),and two diatoms(Chaetoceros muelleri and Cyclotella meneghinia,na).Our results indicated that C.saccharophila was not a suitable food for larval P.dubia,as all larvae fed this microalga died at stage Ⅲ(as copepodites).The survival rates of P.dubia larvae fed C.muelleri,Ⅰ. zhanjiangensis,and P.subcordiformis were significantly higher than that of larvae fed C.meneghiniana.In the adult stage,copepods fed C.muelleri,I. zhanjiangensis,and C.meneghiniana produced more nauplii(430-566 nauplii/female),had higher intrinsic growth rates(0.2-0.253/d),and better longevity(59-60 days)than those fed P.subcordiformis.Our results therefore suggest that P.dubia has different nutritional needs and food preferences at different life stages.For example,P.subcordifonnis was suitable for developing larvae but not for breeding adults,while C.meneghiniana was suitable for breeding adults but not for developing larvae.Both C.muelleri and I.zhanjiangensis were excellent foods for P.dubia throughout the entire life cycle.     

GDELT数据网络化挖掘与国际关系分析

21世纪以来的国际关系错综复杂、瞬息万变,给世界的经济、安全、外交等带来了深刻变化。这些变化对中国的内外政策产生了重大影响。全面及时地分析国际关系及其变化特征,对于中国的经济和外交发展规划具有重要参考价值。国际关系研究具有复杂性、及时性、时空性等特点,迫切需要时空大数据分析技术为其提供新的思路和技术手段。大众媒体如报纸、广播等记录着世界上发生的各种各样的事件,蕴含着丰富的信息,相对于记录个人活动的社交媒体数据,其更加适合于对人类社会进行大规模和长时间的分析。GDELT是一个免费开放的新闻数据库,它实时监测世界上印刷、广播、网络媒体中的新闻,对其进行文本分析并提取出人物、地点、组织和事件等关键信息。本文利用复杂网络的理论和方法对GDELT进行网络化挖掘并进一步分析国家关系。首先利用该数据构建国家交互网络,然后通过网络特征统计分析国家之间的交互关系,最后探测国家冲突事件交互网络的时序变化。研究发现：① 国家交互网络具有无标度特性,网络连接在整体和局部上都呈现出不均匀性,少数国家与其他国家有大量交互,大多数国家与其他国家的交互很少;一个国家与少数国家有大量交互,而与大多数国家的交互很少。② 国家冲突事件交互网络的突然变化往往对应一些重大事件。本文的研究可以为大数据时代的国际关系探索提供一个新的视角,同时也为新闻媒体数据的分析提供参考。     

Consumption of Ecosystem Services in Laos

The exponential increase of ecosystem utilization has instigated a serious conflict between ecosystem services and residents’ needs. The Belt and Road Initiative has greatly influenced Laotian production and living, and the scientific assessment of the consumption of ecosystem services in Laos is important for exploring residents’ influence on the ecosystem. Based on data for the Laotian consumption of agricultural products, fruits and livestock products during 1961-2013, normalized by either harvest index or feed conversion ratio, this study draws three main conclusions. 1) Ecosystem service consumption in Laos is centered on the consumption of farmland, forestry and grassland ecosystem services, which account for over 80%, over 10% and under 2%, showing downward, upward and constant trends, respectively. The consumption of these ecosystem services shows a trend of increasing first, then fluctuating, and finally increasing. 2) The consumption of ecosystem services in Laos was characterized by the mode of “dominance of consumption of the farmland ecosystem services” from 1961 to 2008, and the mode of “balanced development of consumption of farmland, forest and grassland ecosystem services” from 2008 to 2013, with a trend of transformation from the former into the latter. 3) The formation and change in the consumption mode of Laotian ecosystem services have been affected by both supply and trade. Laos developed agriculture mainly during the period from 1961 to 2008, forming the mode of “dominance of consumption of the farmland ecosystem services”. This development benefited from the enriched varieties of imports as well as the increased value of trade and import volume. However, the consumption of ecosystem services in Laos after 2008 changed from the mode of “dominance of consumption of the farmland ecosystem services” to one of “balanced development of consumption of farmland, forest and grassland ecosystem services”. This study provides an empirical reference for research on the consumption of ecosystem services.