基于GIS和遥感技术的生态系统服务价值评估研究进展

生态系统服务价值评估是当前生态系统管理领域研究的热点,密切联系着人类的生活福祉.本文系统综述了基于地理信息系统(GIS)和遥感(RS)技术的生态系统服务价值评估的研究进展,归纳为以下3个特征：生态经济学理论作为价值定量计算的核心方法被普遍采纳;GIS和RS在数据获取、时空分析和集成平台方面发挥着关键作用;运用生态系统服务功能机理模型模拟自然现象与人类活动之间的关系.根据目前该领域的研究现状及不足,提出了可扩展、分布式的集成研究框架--“生产线”框架,探讨了GIS和RS技术与生态系统服务价值评估集成研究的未来发展趋势.     

盘锦地区湿地生态系统服务功能价值估算

随着湿地研究的展开和深入,湿地生态系统的服务功能价值越来越受到人们的重视,以辽河三角洲盘锦地区湿地为例,结合地理信息系统和野外调查及实验,综合运用环境经济学,资源经济学,模糊数学等研究方法,对该地区的湿地生态系统的服务功能进行了价值评估,得到该地区湿地生态系统的服务功能价值为62.13亿元,是该地区国民生产总值的1.2倍,并根据估算结果,讨论了不同方法在估算过程中存在的优缺点。     

生态系统服务价值评估研究进展——国外学者观点

生态系统服务的价值评估是目前生态学研究热点和存在较多争议的领域之一。争论的焦点主要集中在生态系统服务货币化评估的必要性和有效性。通过对大量文献的检索,较为系统地总结了国外学者的观点,特别是引起诸多争论的主要原因：一是由于生态系统本身的复杂性,各项服务之间存在着相互依赖的关系,使生态系统服务的分类本身就缺乏严格的标准,同时存在着时间和空间上复杂的尺度转换问题,从而使生态系统服务的价值评估容易出现重复计算;二是由于经济学方法本身存在着一定的局限性,对于不同的评估对象和评估目标往往需要选取不同的评估方法,每一种生态系统服务通常可以有几种不同的评估方法,评估结果在很大的程度上依赖于选择的不同方法．从而使得到的结果间缺乏可比性;三是由于生态系统不同于经济系统。有时用经济学方法对生态系统进行评估时往往很难反映出自然系统的价值,特别是当人类对生态系统服务的偏好随着时间和新信息的出现而发生变化时,可能会出现更大的差异。今后的研究应当着力于上述困难的解决,以便使生态系统的评估结果更加客观可信,为生态补偿机制建立和生态系统管理等提供有力支撑。     

生态系统服务与自然资本价值评估

生态系统服务是生态系统提供的商品和服务,是人类生态和发展的物质基础和基本条件,是人类拥有的关键自然资本。概述了生态系统服务的内涵及类型,介绍了当前国内外有关生态系统服务及自然资本的价值理论、价值评估的各种方法及其类型;评述了研究的主要进展,存在的主要问题、难点和研究的主要趋向。认为生态系统服务及自然资本的价值评估研究是建立生态－环境－经济综合核算体系（可持续发展核算体系）的重要内容和关键环节,完善价值评估的理论与经济技术方法是生态系统服务价值评估研究亟待解决的问题。     

湖泊生态服务受益者分析及生态生产函数构建

生态系统服务管理作为生态系统管理的优化方式,是生态学研究的前沿方向。湖泊生态系统服务管理是指综合利用生态学、经济学、社会学和管理学等学科知识,对影响湖泊生态系统结构、过程、功能的关键因子进行调控,提高湖泊生态系统服务供给水平和供给能力的过程。近年来国内外学者针对湖泊生态系统服务内涵、分类、经济价值评估等方面开展了大量研究,极大地促进了湖泊生态系统服务从认知走向管理实践。然而,现有研究在开展湖泊生态系统服务价值评估时多忽略生态系统服务受益者和生态系统特征对生态系统服务的边际影响分析,无法揭示生态系统服务空间流动和转移特征及生态系统服务时空权衡关系,制约了生态系统服务研究与管理决策和政策设计结合。在综述湖泊生态系统服务定量评估方法的基础上,认为通过生态系统服务受益者分析确定湖泊生态系统最终服务,并通过构建生态生产函数确定湖泊生态系统服务权衡关系及湖泊生态系统特征对生态系统最终服务的边际影响,是生态系统服务走向管理实践和政策设计的科学依据,可以确保生态、社会、经济可持续发展。     

生态系统服务价值评估方法综述

基于相关科学研究文献,首先对生态系统服务价值评估的国内外研究现状进行追踪与分析;其次,从评估过程的角度,将生态系统服务价值评估方法分为两类:直接评估法和间接评估法,同时进一步对这两类方法进行了分类,并对分类后的评估方法在概念内涵、计算方法等方面进行了总结;最后,文章讨论了目前价值评估方面存在的问题,对生态系统服务价值的评估理论、评估方法及评估结果表现形式进行了总结,并对其未来发展方向提出了建议:加强不同生态系统服务价值评估方法的对比验证及综合应用研究,加强植被覆盖较少或无植被覆盖地区的生态系统服务价值评估研究,加强复合生态系统和精细尺度的生态系统服务价值评估研究。     

生态系统服务价值评估的研究进展

自然资本、人力资本和人造资本是支持人类生存和发展的三大资本,与后两者对比而言,自然资本及由其提供的生态系统服务缺乏完善的经济价值评估系统。近年来,在生态学家和经济学家的共同关注下生态系统服务价值评估的研究已经取得较好的进展。本文从能量学和经济学两个方面介绍生态系统服务价值评估的理论基础,通过对研究案例的分析和总结,提出生态服务价值评估在方法和技术上的几个改进方面,主要包括生态服务单价的生物量订正法、空间尺度问题的转换、条件价值评估法的改进以及动态模拟模型的应用。生态系统服务价值评估还存在某些问题有待今后发展的理论和方法来改进和完善。     

生态系统服务价值的生态区位修正方法——以北京市为例

生态系统服务价值评估是当前生态经济学和环境经济学的研究热点和焦点,生态区位是影响生态系统服务价值的重要因子。以北京市为例,对北京市进行生态区位的划分,遵循资源稀缺性原理,将不同生态区位赋予不同的生态区位系数,并以北京市1980年、1995年和2000年土地利用图为例,以生态区位系数对北京市用地类型的生态服务价值进行修正,以体现不同生态区位单位面积生态系统服务价值的不同。研究得到了北京市3期土地利用单位面积生态系统服务价值分布图。分析发现:北京市的生态系统服务价值组成中,水田、有林地、灌木林和水体的生态系统服务价值占的比重较高;各生态区位生态系统服务总价值从城区到近郊平原区到近郊半山区到远郊山区依次增加;从1980年到1995年,北京市的生态系统服务价值减少了1.21×107元,而且各生态区位的生态系统服务价值也大都减少;从1995年到2000年,北京市的生态系统服务价值有所提高,但与1980年相比还是减少了3.07×106元。     

生态系统的净化服务及其价值研究

生态系统对环境的净化服务是其向人类提供的重要服务功能之一,了解生态系统的净化机理及其价值,对自然资源的保护及其可持续利用有着十分重要的作用。本文讨论了生态系统的净化服务的机理,提出了生态系统净化类型,在此基础上,运用经济学和环境经济学原理,探讨了生态系统的净化价值评估方法,以我国森林生态系统为例,对生态系统的净化价值进行了估算。     

土地利用/覆被变化与景观服务:评估、制图与模拟

从景观尺度上探讨生态系统服务功能的研究越来越引起国内外学者的重视.相比生态系统尺度,景观尺度是探索人类活动对土地利用/覆被变化影响、探究可持续景观演变机理和过程的最佳尺度.基于对当前国际学界对景观服务研究进展的系统梳理与分析,本文探讨了景观服务的内涵与分类,并对景观服务价值评估、制图与模拟等研究方法进行归纳与分析,并对景观服务的未来研究趋势进行展望.景观服务研究的未来方向应进一步明确景观服务的内涵及其分类体系,不断完善和发展景观服务评估、制图与模型模拟方法,重点开展景观格局-过程-服务-尺度长期综合研究,继续加强景观生态学及景观经济学等理论与方法在景观服务研究领域中的应用.     

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.