珠江流域地形特征

本文根据大地弧形构造及板块理论研讨珠江水系的发育、形成特点。从珠江源头到水系的地形分区,并按云贵高原、两广丘陵、珠江三角洲分别论述其自然地理条件及开发利用对策。     

Samuel Palmer and the Pastoral Vision

Colin Harrison , Senior Curator of European Art at the Ashmolean Museum in Oxford, describes how the English 19th-century artist Samuel Palmer was deeply influenced by the poet and painter William Blake. Palmer's sublime paintings of the 1820s placed a new emphasis on the harmony of nature, reinterpreting traditional subjects entirely afresh, placing the Holy Family not in the Holy Land, but in the English countryside.     

Third Natures: Incubators of Public Space

Cristina Díaz Moreno and Efrén García Grinda , founders of the Madrid-based office AMID.cero9, shift the notion of the urban from the classic idea of the complete or ideal city, to one which engages with essential urban phenomena: the dynamics of confrontation, dispute and agreement between individuals, social groups and subcultures. In this way, public spaces are transformed from empty spaces into a real context for social interaction; and active involvement with social exchange becomes the main purpose of a project for a new architecture of the city.     

Human DDX17 Unwinds Rift Valley Fever Virus Non-Coding RNAs

Rift Valley fever virus (RVFV) is a mosquito-transmitted virus from the Bunyaviridae family that causes high rates of mortality and morbidity in humans and ruminant animals. Previous studies indicated that DEAD-box helicase 17 (DDX17) restricts RVFV replication by recognizing two primary non-coding RNAs in the S-segment of the genome: the intergenic region (IGR) and 5′ non-coding region (NCR). However, we lack molecular insights into the direct binding of DDX17 with RVFV non-coding RNAs and information on the unwinding of both non-coding RNAs by DDX17. Therefore, we performed an extensive biophysical analysis of the DDX17 helicase domain (DDX17_135–555) and RVFV non-coding RNAs, IGR and 5’ NCR. The homogeneity studies using analytical ultracentrifugation indicated that DDX17_135–555, IGR, and 5’ NCR are pure. Next, we performed small-angle X-ray scattering (SAXS) experiments, which suggested that DDX17 and both RNAs are homogenous as well. SAXS analysis also demonstrated that DDX17 is globular to an extent, whereas the RNAs adopt an extended conformation in solution. Subsequently, microscale thermophoresis (MST) experiments were performed to investigate the direct binding of DDX17 to the non-coding RNAs. The MST experiments demonstrated that DDX17 binds with the IGR and 5’ NCR with a dissociation constant of 5.77 ± 0.15 µM and 9.85 ± 0.11 µM, respectively. As DDX17_135–555 is an RNA helicase, we next determined if it could unwind IGR and NCR. We developed a helicase assay using MST and fluorescently-labeled oligos, which suggested DDX17_135–555 can unwind both RNAs. Overall, our study provides direct evidence of DDX17_135–555 interacting with and unwinding RVFV non-coding regions.     

基于颗粒形状参数的火山渣桩侧摩阻特性研究

由于形状参数较一般土体差异较大,已有桩基工程中的传统经验难以适用于火山渣地层。为分析东非裂谷区火山渣地层内灌注桩桩侧摩阻,利用四根钻孔灌注桩的现场静载试验测试火山渣地层的桩侧摩阻值,并对火山渣级配、颗粒形状(棱角度和表面粗糙度)、抗剪强度等物理力学性质进行试验。通过与一般角砾土进行对比,分析二者在颗粒棱角度和表面粗糙度上的区别及其对内摩擦角和桩侧摩阻的影响。结果表明:颗粒形状影响颗粒的内摩擦角和桩侧摩阻;火山渣虽属于角砾范畴,但因其棱角度和表面粗糙度远大于一般角砾,导致该土体在稍密状态下,不仅内摩擦角(42°)与一般角砾土的中密程度上限值(36°～42°)相当,桩侧摩阻极限值(124 kPa)也不低于规范中中密角砾土(90～150 kPa)。研究成果可为火山渣地层桩基工程设计施工提供一定的参考依据。     

论地震周年九寨沟景区餐饮状况及对策

四川汶川大地震给四川旅游及餐饮业造成了重大损失,本文通过大量的统计数据阐述了地震周年九寨沟景区的餐饮状况、地震后国家对旅游景区的政策支持、九寨沟旅游景区餐饮企业的自救情况等,并对振兴九寨沟旅游景区的餐饮提出了具体对策。     

中国牛形古村落--安徽黟县宏村

安徽省黟县东北部的宏村，融自然景观和人文景观为一体，恰似山水长卷，被誉为“中国画里的乡村”。其将整个村子构建成“牛”型结构布局的理水艺术，更是被誉为当今世界历史文化遗产的一大奇迹。2000年11月30日被联合国教科文组织世界遗产委员会列入世界文化遗产名录。     

The Hydro-Ecology of Limestone Springs in the Wye Valley, Derbyshire

Springs are unique freshwater habitats and represent ideal sites in which to examine the relationship between environmental variables and macro-invertebrate communities. The results of three case studies infer that species assemblages are determined by the physical habitat conditions within a spring and the ecological requirements of the component species. The composition of the macro-invertebrate community changes significantly along the longitudinal gradient of a spring-brook, as predicted by ecological theory. The results of the case studies are examined in relation to the conservation and protection of these little-studied habitats, and suggestions are made as to how to achieve this in the Wye Valley.     

British colonial civic improvement in the early twentieth century: E. P. Richards in Madras,Calcutta, and Singapore

E. P. Richards’ Calcutta report of 1914 has been reprinted as a key text in planning history, but little is known of the man himself, compared with other planners active in the British colonies during the early twentieth century such as Geddes and Reade. This article seeks to rescue Richards from obscurity, and position him in the context of the new town planning movement in the first quarter of the twentieth century. A basic narrative of Richards’ career, taken mainly from his membership records and obituary at the Institute of Civil Engineers’ headquarters in London, covers his key periods with the Derwent Valley Water Board (working on the Birchinlee model village) and the Calcutta and Singapore Improvement Trusts between 1901 and 1924.     

四川干热河谷地区公路生态植被恢复与重建模式探讨

分析了四川干热河谷地区公路周边自然植被条件与海拔高度的关系,以国道318线二郎山至康定公路为例,对干热河谷地区公路生态恢复与重建的模式进行了研究,根据道路所处海拔高度的差异把全路段分为二郎山、泸定大渡河、康定瓦斯沟三段,根据各段气候和植被特点确定恢复模式,经过2年的生长观察,证明各恢复模式都取得很好的效果,乔灌木的平均成活率达到85%,草坪地被覆盖率平均达到93%;最后,总结了干热河谷道路生态恢复与重建的特殊技术。