生态系统游憩服务功能维度及其形成——以三江源国家公园为例

已有研究主要从规模角度分析生态系统游憩服务,较少分析其结构。结合生态系统服务理论与旅游体验理论,基于旅游者的生态体验提出生态系统游憩服务功能维度的理论模型,并以三江源国家公园为案例区,采用问卷调查搜集数据,运用因子分析与结构方程模型分析数据、验证假设。研究表明,生态系统游憩服务包括美感体验、游憩机会与适宜环境3个功能维度,其形成受到地形、地表覆被、独特景观、景观格局、植被、保护地空间类型、天气与海拔等要素的影响。在不同区域,由于生态要素条件、旅游者对生态要素与各功能维度的感知和态度存在区别,生态系统游憩服务结构呈现出功能和结构差异性。研究解析了生态系统游憩服务的功能维度,深化了生态系统游憩服务研究,有助于完善生态系统游憩服务理论,优化生态要素管理方式。     

基于CPTED理论的大学校园环境安全评价研究——以华南理工大学五山校区为例

在当代大学校园开放性与内聚性双重特性影响下,如何建设平安校园是校园环境设计的一大难题。本文采用问卷调查结合深度访谈的方法,分析学生对校园整体环境的安全评价并绘制安全感知地图,利用统计分析方法对CPTED六要素相关性展开分析并对其重要程度进行排序,发现安全评价较低地点分布于校园边际空间及夜间可视性较差的地点。通过对校园整体环境展开实地调研,基于CPTED六要素提炼13个校园环境安全评价要素,提出校园环境安全设计的优化建议,以期为相关校园规划及环境设计提供参考。     

森林景观斑块密度及边缘密度动态研究——以关帝山林区为例

景观异质性是景观的基本属性 ,是形成不同景观结构和功能的基础 ,直接影响资源、物种和干扰在景观中的分配与传播 ,影响景观的生物多样性和生产力 ,对景观整体功能及生态过程有重要控制作用[4 ,7,8] ,对景观要素斑块动态的影响尤需作具体而深入的研究[3,5,6 ] 。景观异质性可以理解为景观内景观要素属性的变异程度[1] 。景观异质性是由景观要素的多样性和景观要素的空间相互关系共同决定的。当景观要素类型一定时 ,同类景观要素以大斑块相对集中的分布格局 ,景观异质性较低 ;以异质小斑块分散分布的格局 ,异质性较高。因此 ,景观异质性可用…     

基于资源环境承载力的国家级新区空间开发管控研究

随着我国城市工业化和城镇化的快速推进,由于不合理的空间开发导致生态空间被挤占、城市资源环境超载现象日益突出。以资源环境承载力为基础的空间开发管控制度是体现生态优先、绿色发展理念,从源头实现城市经济社会发展和环境协调发展的重要路径。选取国家级新区江北新区为案例地区,通过构建涵盖生态保护重要性、土地承载力、环境容量、环境压力4个要素层、10项具体指标的评价体系,基于GIS空间分析工具评估区域资源环境承载力。研究表明江北新区资源环境承载力呈现由沿江向内陆、平原地区向丘陵地区逐级递减趋势,根据要素层在空间分布差异性,将区域分为资源环境承载力饱和区域、资源承载力尚好但环境压力较大区域、资源承载力较好且环境压力较小区域、生态环境安全保障区域四个类型,并制定差异化的空间准入和管控措施。研究不仅为资源环境要素全面融入国家新一轮空间规划体系制定和实施全过程提供技术支撑,也可为长江经济带制造业发达地区探索可持续发展空间开发路径提供案例借鉴。     

城市绿地空间形态对PM2.5的消减影响——以武汉市为例

缓解大气颗粒物污染、营造清洁健康的城市环境是中国绝大部分城市须解决的问题之一。城市绿地能有效缓解PM2.5,然而当前对绿地空间形态的研究不足,导致能在规划设计中直接应用的成果不多。基于武汉市9个城市绿地空间形态要素量化差异与实地测量的PM2.5浓度大小,探索二者深层的量化关系规律。结果显示：1）PM2.5消减量随绿地规模的增加呈增长趋势,当规模大于5~10 hm2消减量减缓;2）绿地面积、周长及形状指数与PM2.5的消减量显著正相关,分维指数与近圆形形状指数相关性不显著;3）PM2.5的消减效率随绿地规模的增加急剧下降,当绿地规模超过5~10 hm2,消减效率变化不明显。通过量化分析,揭示对PM2.5消减具有显著影响的城市绿地空间形态指标,提出适当的规模、不规则或复杂的绿地形态及分散式的布局等绿地优化策略。     

基于生态认知的校园雨水花园设计

生态认知视角下的校园雨水花园设计旨在探讨生态语境下校园景观的教育作用。环境教育中的无意识教育方式是通过环境的感染力潜移默化影响受育者,无意识教育方式为受育者提供的开放性、自主性和互动性的教育途径更能深刻影响受育者的认知。基于生态认知的校园雨水花园设计以无意识环境教育思想为指导,运用生态显露设计,以可视化雨水路径刻画雨水生态特征,以满足花园功能、技术和艺术要求且实现可视化雨水路径的空间设计与艺术品质,创造雨水花园的张力场效应和感染力,如空间秩序、材质对比、色彩运用以及空间的愉悦体验等,以促进生态的无意识教育     

空间尺度对地形异质性-物种多样性关系的影响:粒度和幅度

空间尺度是影响我们理解生态学格局和过程的关键因素。目前已有多种关于物种多样性分布格局形成机制的假说且研究者未达成共识,原因之一是空间尺度对物种多样性分布格局的环境影响因子的解释力和相对重要性有重要影响。地形异质性是物种多样性分布格局的重要影响因素。本文综述了在地形异质性-物种多样性关系的研究中,不同空间粒度和幅度对研究结果的影响,以及可能的原因。尽管已认识到地形异质性-物种多样性关系的空间尺度效应,但粒度和幅度的具体影响仍未有统一结论。当前物种多样性分布格局研究未能覆盖较完整的尺度变化梯度。未来对地形异质性-物种多样性关系的研究需要同时考虑幅度和粒度的影响。建议结合可靠的模型和统计分析方法开展多尺度格局比较分析,以进一步阐明研究尺度对地形异质性-物种多样性关系的影响以及地形异质性起主导作用的空间尺度。     

长江中游城市群城市生态承载力时空格局及其影响因素

长江中游城市群是我国的典型生态敏感区和重点开发区,科学评价其生态承载力具有重要的科学价值和现实意义。从城市生态系统的组成要素、结构特征出发,选择状态空间法从社会经济协调力、资源环境支撑力和生态弹性力3个维度构建了城市生态承载力综合评价指标体系,综合运用空间分析、多元回归、地理加权回归等方法深入分析了2006—2015年长江中游城市群城市生态承载力时空格局及其影响因素。结果表明:①2006—2015年长江中游城市群城市生态承载力指数总体呈波动上升的"W"型走势,社会经济协调力维度呈波动下降的趋势,而资源环境支撑力和生态弹性力维度整体呈波动上升的趋势;②从空间格局来看,2006—2015年长江中游城市群城市生态承载力表现出显著的空间关联性与异质性,环洞庭湖地区和环鄱阳湖城市群地区形成两大高值集聚区,而在武汉城市圈和环长株潭城市群核心区域形成两大低值集聚区;③社会发展水平、城镇居民收入水平、人口密度、经济发展效率、资源供给状况和环境污染治理水平等要素对长江中游城市群城市生态承载力空间分异格局的影响较为显著,影响强度具有空间异质性特征。     

基于生态导向的城市空间优化与功能组织——以天津市滨海新区临海新城为例

以生态学理论为指导,全面统筹建设城市的生态环境、社会环境、经济环境和物质形体环境的城市规划手段是实现城市自然-经济-社会和谐、高效、持续发展的重要途径。研究以天津市滨海新区临海新城为例,借鉴景观生态学分析方法,提出基于生态导向的城市空间优化和功能组织的规划思路：基于城市生态环境现状评价和问题诊断基础,整体优化生态景观格局;利用GIS空间分析技术进行城市生态适宜性和敏感性分析,划分城市生态功能区;结合城市职能定位和产业选择,确定自然生态因子和经济活动的镶嵌关系,优化城市产业活动的空间配置。实证研究的结果表明：基于生态导向的城市空间优化与功能组织将城市规划引向重建自然和保护自然的空间塑造过程;城市生态网络空间的构建决定了城市“组团状”的功能组织和空间布局模式;基于生态分析的城市空间优化保障了城市生态系统的健康持续发展。     

城市街道景观特征与连续性评价方法研究

随着对城市建设问题的深入认识,人们对城市街道景观的认知已从三维空间建构转向空间体验与感受。以视觉认知为基础,采用视觉认知画面为手段,对城市街道进行量化研究。以画面占有率的数值变化反映街道景观特征,以画面占有率的样本方差值反映街道景观的连续性。以街道贴线率为影响因素,通过相关性分析,考察了贴线率如何对街道景观特征与连续性产生影响。     

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.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.