城市生态系统健康综合评价

生态系统健康是生态学领域的研究热点之一.文中提出了对城市生态系统健康概念的理解; 从状态空间的角度, 解释了城市生态系统健康的内涵,并以此为基础,提出了目前研究中存在的不足; 从复合生态系统的角度,提出了一种新的城市生态系统健康评价方法——综合评价方法; 构建了城市生态系统健康综合评价模型,并将该方法应用于佛山市城市生态系统的健康评价.结果表明, 在研究时段内,佛山市城市生态系统健康水平逐年上升;综合评价方法不仅能反映城市整体健康状况,而且能辨别各子系统的相对健康水平,具有一定的理论价值和可操作性.     

基于能值分析的合肥城市生态系统健康动态评价

随着城市化和城市环境问题的日趋突出,城市生态系统健康评价成为近年来生态学领域研究的热点.本文运用能值分析方法,采用活力、组织结构、恢复力和服务功能维持4个要素,构建了评价城市生态系统健康的能值指标--城市健康能值改良指标,并用于合肥市生态系统的健康评价,然后将评价结果与天津、芜湖、上海、宁波、福州等6座国内城市进行比较...     

基于熵理论的城市生态系统服务流定量评估——以北京市为例

量化评价生态系统的服务功能是合理开发生态资源、实现可持续发展的重要前提.生态系统服务流能够为生态系统服务功能的量化评估提供解决方案.本文以四大生态系统服务类型为框架,构建了城市生态系统服务流评估体系;将生态系统服务流重新分类,引入熵理论,对指标及系统无序度、发展演变方向进行定量评价;并以北京市为研究对象,选择24个因子开展案例研究.结果表明:2004—2015年间,北京城市生态系统服务总熵值为0.794,总熵流为-0.024,系统无序度较大,濒临非健康状态;系统熵值3次取得极值,3个变化周期内系统熵值的年平均变化幅度逐渐增大,说明人为活动对城市生态系统干预强度增大;2007年熵流达到最小值,生态环境质量最高;北京市常住人口总数与城市生态系统熵流拟合函数的决定系数为0.921,说明人口数量与城市生态环境状态有很强的相关性.     

基于属性理论的城市生态系统健康评价——以重庆市北部新区为例

确定了城市生态系统健康评价指标体系,提出了基于属性理论的城市生态系统健康评价模型及评价方法。以重庆北部新区为对象,运用该模型和方法对重庆北部新区生态系统健康现状进行了评价。结果表明:重庆北部新区城市生态系统现状属于一般健康类;基于评价结果识别健康限制因素,提出了生态系统健康调控措施。     

基于投影寻踪的城市生态系统健康评价

掌握城市生态系统的健康水平,对城市实施可持续发展具有重要意义.采用一种新型的多指标数据处理方法-投影寻踪模型,选取典型指标,利用基于实数编码遗传算法优化求取最佳投影方向,对广州市2000年、2005年的城市生态系统健康状况进行评价.评价结果表明:2000年,广州市对应的等级值为2.95,处于亚健康状态,符合其客观状况,该结果与采用模糊综合评价法所得结论一致;2005年,广州市对应的等级值为3.48,仍处于亚健康状态,但其等级值大于2000年的数值,等级值在增大,表明经过5a的建设,广州市的生态系统健康状况在不断好转.此外,与模糊综合评价法相比,该模型能精确地刻画出生态系统的具体健康水平,具有较高的评价精度和区分度.     

基于绿视率的城市生态舒适度评价模型构建

城市生态系统服务指人类从城市生态系统中获取的利益,城市绿色空间是提供城市生态系统服务的主要载体。而城市化进程的加快对城市绿色空间的存量造成威胁,城市生态系统服务难以达到居民需求。传统的城市绿色空间评价指标集中于对城市绿地面积的评价,指标偏向整体性和二维化,忽视了三维绿量,也鲜少关注生态系统服务质量。基于以上背景提出了一个城市生态系统服务功能评价指标——城市生态舒适度,通过人体的主观感受对城市生态系统服务功能做出质量反馈,并结合灰色关联分析法构建了该指标的评价模型。通过样本的条件对比分析得出,当绿视率水平低于30%时,城市生态舒适度的主要影响因子为绿视率;当绿视率水平高于30%时,则是湿度、PM2.5浓度和风力等级。将评价模型的模拟结果与实测值进行对比验证,结果显示二者的变化趋势基本相同,表明评价模型科学有效。     

城市生态系统的动力学演化模型研究进展

从系统分析出发,对城市生态系统的动力学演化模型的发展历程、建模的方法和步骤过程、软件开发方法和目前的模型软件等进行了总结。归纳了城市生态系统的动力学演化建模的方法,主要包括模型定义、模拟、实现、验证、分析和应用等六大步骤。目前国内外用于城市生态系统动力学演化模型的主要方法有：基于数理模型的方法、生态控制论和灵敏度模型、系统动力学模型、多目标规划法等。已经开发的用于城市生态系统的动力学模拟的软件可以划分为两类：基于土地利用和交通规划的专业模型和基于系统动力学和灵敏度模型的一般软件。总结了常用的城市演化模型软件,讨论了模型的研究对象和应用范围。分析了城市生态系统的动力学演化模型建模的不确定性的来源,并指出：向宏观和微观两极化发展是城市生态系统动力学演化模型的发展趋势之一,而与人工智能和地理信息系统等新方法的集成是发展的另一趋势。城市生态系统动力学演化模型的开发前景在于对不确定性问题的定性、定量分析,而多模型的耦合和集成是发展的必然趋势。     

基于能值分析的城市生态系统健康评价——以包头市为例

城市生态系统健康是城市生态学界近年来的研究热点和前沿.采用能值评价方法,结合城市生态系统作为复合系统所具有的生态服务功能,明确提出基于能值进行城市生态系统健康评价的理论框架和技术路线,得出表征城市健康程度随时间的变化走向和比较意义.针对城市生态系统健康表征特性,采用4个要素,即活力(V)、组织结构(O)、恢复力(R)和服务功能维持(F), 构建了评价城市生态系统健康的新的能值指标--城市健康能值指标(EUEHI),并将EUEHI应用于包头城市生态系统健康评价中,并比较了其他5个城市的EUEHI.结果显示2000～2004年包头健康程度总体呈现上升状态,健康等级不断提高,但同中国其他城市之间尚有距离,健康程度仍处于较低水平.这说明近几年包头重视改变资源结构和利用效率,使得城市生态系统在生态系统服务功能维持方面得到不断改善.同时,包头作为老工业城市组织结构尚不完善,环境负荷大,生态系统承载力逐年降低,因此仍需从降低环境胁迫入手,逐步降低城市生态系统干扰,使其恢复力得以提高,增加系统反弹恢复的容量,使之恢复维持结构与格局的能力,实现城市健康和谐发展.     

生态系统综合评价的内容与方法

生态系统综合评价是系统分析生态系统的生产及服务能力,对生态系统进行健康诊断,做出综合的生态分析和经济分析,评价其当前状态,并预测生态系统今后的发展趋势,为生态系统管理提供科学依据。从总体上讲,综合评价更强调生态系统一系列产品与服务功能之间的权衡,具有很强的实践意义。许多学者对不同的生态系统服务功能进行了经济价值评估,但缺乏对生态系统的产品、服务、健康与管理之间关系的进一步探讨。对生态系统服务功能评价、健康评价的生态管理与预测进行了系统论述,目的是提出生态系统综合评价的框架,指导生态系统评价行动及生态系统管理。     

滨海红树林湿地生态系统健康的诊断方法和评价指标

健康的红树林湿地生态系统是指系统组分之间及系统整体维持动态的平衡,在适度的自然与人为干扰下,红树林生态系统服务功能发挥正常。本文筛选并评述了包括指示物种法、结构功能指标法、生态系统失调综合症诊断法、生态系统健康风险评估法、生态脆弱性和稳定性评价、生态功能评价法等6种可用于红树林湿地生态系统健康的诊断方法,分析了各自的应用前景。以压力-状态-响应模型为主线,构建了红树林湿地生态系统健康评价指标体系。在未来研究中,需进一步加强指标的筛选、评价标准与权重的确定,将生态系统健康水平与其生态服务功能相关联,开展具体案例分析。     

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.