首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 73 毫秒
1.
郭家山遗址是目前发现的距江苏南京城区最近的,较大型的湖熟文化遗址.遗址商代至西周春秋文化层的植硅体分析,揭示出南京地区在商代(约3 500-3 000 aBP)气候偏温、偏湿;西周(或西周早期)(约3 000-2 800 aBP)气候温和湿润;西周战国时期(约2 800-2 500 aBP)气候偏温、偏湿.与相邻地区同...  相似文献   

2.
榆林地处农牧交错带,是研究环境演变和人地关系的理想地区。本文基于植硅体分析,探讨了该地区王阳畔遗址仰韶晚期至龙山早期过渡阶段的农业生产情况及农业对环境的适应等。遗址剖面及灰坑样品的植硅体分析表明:仰韶晚期,粟和黍是先民的主要粮食作物,而黍较粟始终保持着种植优势;龙山早期,粟作农业逐渐衰落。植硅体组合图谱显示,先民在此遗址活动期间,气候是略偏凉偏干的,整体上较为稳定,呈现出干凉化的趋势。综合来看,农业活动的强弱在一定程度上响应了环境的变化。需要指出的是,该遗址榆科植硅体的大量发现,不仅补充了史前植物利用史,同时也对丰富植硅体数据库具有重要意义。  相似文献   

3.
榆林地处农牧交错带,是研究环境演变和人地关系的理想地区。本文基于植硅体分析,探讨了该地区王阳畔遗址仰韶晚期至龙山早期过渡阶段的农业生产情况及农业对环境的适应等。遗址剖面及灰坑样品的植硅体分析表明:仰韶晚期,粟和黍是先民的主要粮食作物,而黍较粟始终保持着种植优势;龙山早期,粟作农业逐渐衰落。植硅体组合图谱显示,先民在此遗址活动期间,气候是略偏凉偏干的,整体上较为稳定,呈现出干凉化的趋势。综合来看,农业活动的强弱在一定程度上响应了环境的变化。需要指出的是,该遗址榆科植硅体的大量发现,不仅补充了史前植物利用史,同时也对丰富植硅体数据库具有重要意义。  相似文献   

4.
成都平原4 000aBP以来的孢粉记录与环境变化   总被引:1,自引:0,他引:1  
成都平原晚全新世以来沉积的泥质层发现丰富的孢粉。根据孢粉成分组合特征和生态类型可划分出5个孢粉组合带,结合剖面上6个14^C测年数据,提出在过去的4000a研究区植被类型及气候环境经历了5个阶段的变化:3800-3600aBP为亚热带常绿阔叶林,气候暖偏湿;3600-3400aBP为含常绿树种的落叶阔叶林,气候温暖湿润;3400-2600aBP为草/湿地,气温下降,环境更潮湿;2600-900aBP为落叶阔叶林,温度又开始逐渐回升,气候温和偏湿;900-300aBP再次变为草/湿地,偏干冷的气候环境。  相似文献   

5.
江苏泗洪顺山集遗址是淮河中下游地区迄今为止发现年代最早的新石器时代遗址之一。本文对遗址三个不同文化时期连续剖面土壤堆积物中的植硅体进行分析,结果显示该遗址先民早在距今8 500年左右已经开始种植水稻,并一直延续到遗址三期(7 500 BP)。植硅体组合分析结果表明,顺山集遗址所处时期的气候总体上较温暖湿润,但存在气候波动,从一期至三期大体上经历了温暖—偏凉—回暖的过程,可能对应了全新世高温期到来之前的气候转暖。从顺山集遗址水稻遗存的连续发现以及水稻驯化水平不断提高来看,气候变冷并未抑制当地稻作农业的发展,相反在一定程度上可能促进了其发展与扩散。本文研究结果对研究全新世早中期中国中东部气候变化背景下人类适应策略提供了重要的科学依据。  相似文献   

6.
本文利用植硅体分析方法,对安徽蚌埠禹会村遗址双墩文化时期44份土壤样品开展植物考古研究,重点关注典型农作物植硅体类型及其形态特征,以及敏感型与固定型植硅体组合特征等。结果显示,禹会村遗址大部分样品中皆发现有水稻特征型植硅体,并未发现粟、黍等旱地作物遗存;水稻扇型及双峰型植硅体形态特征分析显示,水稻遗存为驯化程度较高的粳型稻。以上研究结果表明,该遗址双墩文化时期的农业结构延续了顺山集文化时期以来种植粳型稻为主的传统。此外,通过水稻植硅体高密度样品中敏感型与固定型植硅体含量比值为0.7±0.2推测,该遗址水稻栽培环境属于“高地势-雨水供给”或“低地势-雨水供给”类型。本文研究结果为探讨淮河中游地区新石器时代农业发展、水稻栽培与驯化以及人类适应策略等问题提供了重要科学依据。  相似文献   

7.
香港壕涌遗址孢粉、植硅石组合及其环境考古   总被引:4,自引:1,他引:3  
香港壕涌遗址孢粉、植硅石组合表明:自新石器时期以来该遗址周围植被以热带-亚热带蕨类植物为主;草本植物以禾本科、莎草、藜科等主为;在遗址附近的高地及山坡上生长了常绿阔叶林,其成分包括:阿丁枫香属(Altingia)、栲属(Castanopsis )、常绿栎(evergrenn Quercus)、棕榈(Palmae)等;植被面貌是人类活动干扰的结果。新石期时期,遗址受海水影响,人类活动以采集、捕捞为主;唐宋时期,禾本科花粉及典型水稻硅酸体的大量出现,反映了稻作农业的发展及人类生存方式的改变。  相似文献   

8.
江苏苏州绰墩遗址孢粉记录与太湖地区的古环境   总被引:3,自引:0,他引:3  
张瑞虎 《古生物学报》2005,44(2):314-321
根据绰墩遗址考古资料和孢粉分析,认为古遗址中的孢粉组合受人类活动影响较大,太湖地区新石器文化的兴衰与该区地势、气候、海平面变化以及太湖碟形湖盆体系的发育有密切关系,绰墩遗址中之所以形成较为丰富的文化内涵,与其较高的地势有关。  相似文献   

9.
西藏扎布耶盐湖晚第四纪孢粉植物群的初步研究   总被引:16,自引:1,他引:15  
扎布耶盐湖位于西藏青藏高原腹地。通过该湖ZK2钻孔的孢粉分析,揭示了约36000aB.P.以来扎布耶地区的气候和湖盆演变。约在36000-33000aB.P.,扎布耶地区为森林草原,气候冷、湿;约33000-30000aB.P.,为灌丛草原,气候温、干;约30000-27500aB,P.为干旱草原,气候偏暖、湿;约18000-12000aB.P.,为干旱草原,环境寒冷,干燥;约12000-4000aB.P.,扎布耶地区各类草本植物繁茂,气候偏温、干。另外,根据水生藻类化石群的分析,自36000aB.P以来,扎布耶盐湖有三次湖进、淡水湖期,同时也有三次湖退事件。  相似文献   

10.
苏州草鞋山遗址新石器时代以来的植硅石研究   总被引:2,自引:0,他引:2  
本文首次对苏州草鞋山遗址新石器时代以来的植硅石进行分析。结果表明:马家浜文化时期气候发展经历了三个阶段。第一阶段(距今约6275a以前)气候温暖湿润,禾本科植物以芦竹亚科、竹亚科和水稻为主;第二阶段(距今约6275-6200a间)气候温凉略干,黍亚科大量出现;第三阶段(距今约6200-5985a间)气温回升。菘泽文化至宋代,气温继续变暖,此阶段,禾本科各亚科植物均有生长。本遗址马家浜文化时期发现典型水稻扇型及亚铃型硅酸体,反映该地自马家浜文化时期以来,水稻栽培已有一定规模  相似文献   

11.
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.  相似文献   

12.
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  相似文献   

13.
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.  相似文献   

14.
15.
16.
鸡传染性法氏囊病病毒研究进展   总被引:3,自引:0,他引:3  
闫笑  李天宪 《中国病毒学》2003,18(2):191-195
传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.  相似文献   

17.
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.  相似文献   

18.
Shen  Jia-Yuan  Li  Man  Xie  Lyu  Mao  Jia-Rong  Zhou  Hong-Ning  Wang  Pei-Gang  Jiang  Jin-Yong  An  Jing 《中国病毒学》2021,36(1):145-148
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).  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号