基于公共安全的城市广场步行空间景观设计研究—以重庆市三峡广场为例

物质空间和人口的高密度发展促进城市快速发展,广场的更新速度与城市发展不同步,步行空间安全系数降低,安全事故发生的概率增大,公共景观作为广场步行空间的构成要素影响步行空间的安全。以重庆市三峡广场为研究对象,基于层次分析法—模糊综合评价法从绿化、道路、水景设计以及景观小品等方面开展景观安全评价,明确景观安全性设计的重点,发现其存在的安全隐患,实现安全评价定性分析与定量计算的有机结合,为广场步行空间公共景观安全性设计与评价提供参考。     

基于社区营造的城市公共空间微更新探讨

随着城市建设进入由增量转向存量的阶段，渐进式的微更新成为城市更新和改造的主要模式。以公众参与为基础、微小社区空间和公共空间设施为改造对象的局部更新方式，成为激发城市活力、提升建成城市公共空间品质的新方式。主要以北京、上海为例，对城市微更新的发展背景加以分析，对微更新背景下的城市公共空间的多重含义进行阐述，在此基础上总提出基于社区营造的城市公共空间的微更新途径，分别是边缘空间的整合和触媒方式的选择、场地历史文脉原真性的挖掘和社区居民社会生活方式的保护、多方协作的开放沟通平台和责任规划师制度的建立。     

城市景观复写——从空间分析到设计途径

当代景观设计中价值取向的转变，包括设计行为从创造画面转向塑造场所，从创造新事物转向重现场地本质与原貌。依据景观设计中的空间特征和规划设计应用价值，将文本视角下的当代景观空间特征“复写”（palimpsest）定义为场地中各历史层次与当代层次的结合与共同显现。复写空间利用场地的潜力，实现了景观意义的传达，具有二元性、互文性及透明性的特点。复写既可以作为分析工具，也可以作为设计手段，其核心价值在于：多层空间结构得以平等呈现；历史信息积累而显现场地特质；设计创造诱发新的发展空间与场地产生关联。结合案例论述，研究与复写相关的分析方法与设计路径：呈现自治或在场地介入过程中建立互设关系，相关设计思想可回溯到埃森曼“人工开挖”（artificial excavation）的设计理念，以及文化景观及遗产保护中的“踪迹”（trace）概念。以场地空间特征出发，选择合适的设计方法，进而提出复写空间的多层建构是设计过程的关键部分。     

上海城市公共开放空间夏季小气候及舒适度

基于2006年5—8月上海城区5种类型公共开放空间（广场、喷泉、草坪、廊道、林地）的空气温度、相对湿度、风速和辐射强度等小气候指标,分析了各空间类型对小气候的调节作用,并采用体感气象指数（discomfort index, DI）作为评价指标,比较了各空间类型对人体舒适程度影响的差异.结果表明：上海市5种类型公共开放空间的平均温度、相对湿度等小气候因子存在一定差异;平均气温依次为广场＞草坪＞喷泉＞廊道＞林地;平均空气相对湿度依次为林地＞廊道＞喷泉＞草坪＞广场;广场面积、喷泉水体附近的风速及风向、草坪的草种类型、廊道的宽度及乔木盖度、林地的盖度及乔木林冠层高度等非气候指标分别与各自空间的气候指标呈显著相关.与其他3种空间类型相比,林地和廊道具有明显的遮荫、降温、增湿作用,对小气候的调节能力更佳.     

城市滨水空间生态系统服务供需匹配的空间智慧

当前生态系统服务空间性研究大多在区域或城市尺度上开展,风景园林生态实践的指导性较为有限,研究聚焦场地尺度,旨在从生态系统服务供需视角看待城市滨水空间的发展与规划设计实践。在已有生态系统服务供需方面文献爬梳的基础上,提出影响需求的三大因素及其需求类型的划分方法,甄别影响城市滨水空间生态系统服务供给能力的核心指标,选取上海苏州河市区段进行实证研究,采取田野调查法、文献研究法,并基于GIS进行需求目标与供给能力的空间制图。通过拟合分析比对创新性地提出指导城市滨水空间生态实践的三大空间智慧：1）基于需求目标研判制定发展策略的空间智慧;2）分段分类型供给满足存量更新需求的空间智慧;3）生态系统服务供需平衡转向匹配的空间智慧,为城市滨水空间的生态实践提出理论依据、评价标准及技术支撑。     

奥本罗历史城区中心——从远期总体规划到公共空间更新

ADEPT建筑事务所与Topotek1事务所最近在丹麦的集镇—奥本罗完成了一个历史城区的改造。在基于当地现状条件完成的公共空间再设计与城市总体规划之间创造了紧密的联系,通过趣味性的设计手法以及对传统材料的创新使用,使历史悠久的城区中心为公共空间的更新做好了准备。此项目的改造基于历史城区中心的特征、规模及过往经历完成,同时也为街道和广场增添了现代感。为满足城市中各类型公共生活而设计的铺装和城市家具强调了这一新特征。在创造从宏观到细节之间明确关联性的过程中,目标是建立一个具有整体性的历史城区中心的鲜明特点,同时也通过局部细节的处理使不同的公共空间各具特色。     

灾后重建背景下城市公共空间设计路径探析

灾后重建关乎灾区长远稳定的发展,不仅受到学者的关注,也是国家、政府高度重视的民生工作,其涉及社会、经济、环境、文化及物理等多个层面。芦山“4·20”地震发生以来,作为灾害的见证者和灾后重建的践行者,以芦山根艺苑广场设计为契机,通过访谈、问卷调查等方法,提出“重塑”的设计理念,以灾后重建中公共空间的生态重塑、文化重塑和公共重塑为研究内容,着眼于以问题为导向、需求为目标的设计框架,探索和归纳灾后重建中城市公共空间的设计路径,体现其本土性、文化性、公共性的价值内涵。     

基于移动测量的城市空间形态对夏季午后城市热环境影响研究

城市空间形态是城市特殊微气候形成的主要因素之一。本研究旨在通过分析2016年及2017年武汉和郑州夏季移动实测数据,探讨不同气候区（夏热冬冷地区和寒冷地区）、不同用地属性（商业和住宅）以及不同城市空间形态指标（天空开阔度、绿化覆盖率、建筑高度和建筑密度）对夏季午后城市热环境形成的影响机理,并基于非线性回归分析,研究城市空间形态各项指标与夏季午后气温的相关性。结果显示,在夏季午后,建筑的遮阴效果是对城市气温影响最为关键性的因素。特别是在郑州,建筑密度和天空开阔度2个因素最为关键,具有显著的相关性。相比之下,武汉气温值与建筑遮阴效果的相关性低于郑州,说明干热环境下太阳辐射对气温的高低起决定性因素,而湿热环境下却并不显著。     

城市地下历史景观的保护实践探析

城市地下考古遗址是城市历史景观的重要组成部分,对城市中心地区地下空间的深度开发是目前发展的重要趋势。在地下空间的规划和设计中对地下历史景观和地下公共空间进行整合,不仅能减少对城市地下历史景观造成破坏,还能充分发挥历史景观的社会文化功能,塑造出富有特色的城市公共空间,促进城市的文化可持续发展。本文以保加利亚谢尔迪卡古文化与交通综合体为例,探讨城市地下空间开发中历史景观的营建经验,以供中国参考。     

城市居住区多功能绿地景观的景感生态学效应

作为居住区绿地景观重要的组成要素,公共活动空间是居民最为频繁使用的空间,对提高绿地生态系统文化服务,改善人居环境与提高居民健康具有重要意义。基于居民休闲娱乐文化感知,探讨居住区绿地公共活动空间的景感生态学效应,揭示多功能绿地景观对生态系统文化服务和景感营造的影响,可为居住区绿地的景观规划与设计提供重要的参考依据。以郑州市26个居住小区80个公共活动空间为研究对象,结合景感生态学理念,基于小区绿地公共活动空间的景感特征（植被覆盖、基础设施、遮荫率、管理水平、公共活动空间面积与类型）以及内部居民休闲娱乐文化活动特征的调查分析,探讨了城市居住区绿地公共活动空间的景感效应对绿地生态系统文化服务的影响。结果表明：（1）小区绿地不同类型公共活动空间提供的景感效应存在显著差异,水体的自然属性使其景感效应更丰富,文化服务价值最高。（2）小区绿地公共活动空间面积越大,居民的心理感知越强,景感体验越丰富,文化服务价值越高,增加公共活动空间面积是构建多功能绿地景观的直接通道。（3）公共活动空间的植被覆盖营造的视感与遮荫率营造的风感生态学效应较为显著,而基础设施的触感与清洁度的视感并未存在显著影响。（4）结合小区社会经济数据的多元回归分析结果表明,由公共活动空间面积营造的多样化景感对居民活动量的贡献最大,其次为公共活动空间的类型与小区户数。运用景感生态学理论和景感营造原则,在有限的空间内通过景观设计实现了景感载体化,改善和增加了绿地生态系统服务,能够缓解城市绿地的不公平性。未来城市居住区特别是高密度居住区应尽可能设置大面积的具有多功能特征的公共活动空间,而低密度居住区在绿地面积充足的前提下,可设置大面积自然水体和增设多类型的公共活动空间,以提高景感效应。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.     

Chemical constituents from the fruits of Rhus typhina L. and their chemotaxonomic significance

This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized.