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101.
江苏省中国科学院植物研究所标本馆(NAS)是中国最早的植物标本馆之一,也是国内最早开展植物标本数字化的标本馆,其标本数字化发展经历了4个阶段: 20世纪80年代后期尝试的标本文字信息数字化的起步阶段; 20世纪90年代末的标本图像数字化和文字信息数字化规范阶段; 2004年以后的标本批量数字化与信息网络共享快速发展阶段; 2018年后的标本数字化信息维护与优化阶段。这一过程集中代表和反映了中国植物标本数字化的发展历程。此外,近年来开始了发掘和利用江苏植物标本的数字化信息工作,包括建设江苏省级数字植物标本馆、开发江苏省维管植物标本时空分布可视化系统、开展标本采集-入库过程数字化等。今后,将不断深化标本数字化的工作,以期形成有NAS特色的数字化植物标本馆。  相似文献   
102.
通过研究多花黄精(Polygonatum cyrtonema)的生态适宜性,为其野生资源保护及人工规范化栽培提供依据。收集237份多花黄精分布位置和55个生态因子,导入最大熵(MaxEnt)模型运算,结合地理信息系统(GIS)分析其适合生长区域。结果表明,影响多花黄精生态适宜性的主要生态因子是3月降水量、年均降水量、6月降水量、5月降水量、4月降水量、2月降水量和最冷季降水量,在福建省具有广泛适宜生长区域。模型预测结果可靠,可为多花黄精野生资源保护提供参考,并为其科学种植提供指导。  相似文献   
103.
Group travel is a familiar phenomenon among birds but the causes of this mode of movement are often unclear. For example, flocking flight may reduce flight costs, enhance predator avoidance or increase foraging efficiency. In addition, naive individuals may also follow older, more experienced conspecifics as a learning strategy. However, younger birds may be slower than adults so biomechanical and social effects on flock structure may be difficult to separate. Gannets are wide‐ranging (100s–1000s km) colonial seabirds that often travel in V or echelon‐shaped flocks. Tracking suggests that breeding gannets use memory to return repeatedly to prey patches 10s–100s km wide but it is unclear how these are initially discovered. Public information gained at the colony or by following conspecifics has been hypothesised to play a role, especially during early life. Here, we address two hypotheses: 1) flocking reduces flight costs and 2) young gannets follow older ones in order to locate prey. To do so, we recorded flocks of northern gannets commuting to and from a large colony and passing locations offshore and used a biomechanical model to test for age differences in flight speeds. Consistent with the aerodynamic hypothesis, returning flocks were significantly larger than departing flocks, while, consistent with the information gathering hypothesis, immatures travelled in flocks more frequently than adults and these flocks were more likely to be led by adults than expected by chance. Immatures did not systematically occupy the last position in flocks and had similar theoretical airspeeds to adults, making it unlikely that they follow, rather than lead, for biomechanical reasons. We therefore conclude that while gannets are likely to travel in flocks in part to reduce flight costs, the positions of immatures in those flocks may result in a flow of information from adults to immatures, potentially leading to social learning.  相似文献   
104.
Glioma is one of the most common primary malignancies of the central nervous system, which has aggressive clinical behavior and a poorer prognosis. MicroRNAs (miRs) are a class of small noncoding RNAs that function as mediators of gene expression, which can be sponged by circRNA provided with a closed circular structure. Dysregulations of circular RNAs (circRNAs) and miRs have been implicated in the development and progression of glioma. In the current study, we investigated the role of circular RNA hsa_circ_0076248 in mediating the oncogenesis of glioma by sponging miR-181a to modulate silent information regulator 1 (SIRT1) expression in vitro and in vivo. The quantitative real-time polymerase chain reaction results showed that the expression of miR-181a was significantly decreased in glioma tissues and cell lines compared with normal brain tissues and normal gliocyte, respectively, and the expression of hsa_circ_0076248 and SIRT1 demonstrated the opposite. Bioinformatics analysis identified hsa_circ_0076248 could sponge miR-181a, and miR-181a could target the mRNA of SIRT1. Our results verified that downregulating hsa_circ_0076248 or upregulating miR-181a could depress the proliferation and invasion of glioma in vitro and in vivo. The experiment also showed that downregulating hsa_circ_0076248 or upregulating miR-181a could remarkably promote the temozolomide chemotherapy sensitivity. Furthermore, Western blot analysis testified that downregulating hsa_circ_0076248 or upregulating miR-181a could promote the expression of p53 and SIRT1. In summary, our study sheds light on the regulatory mechanism of hsa_circ_0076248 in glioma growth and invasion via sponging miR-181a, which downregulates the SIRT1 expression and also suggests that hsa_circ_0076248, miR-181a, and SIRT1 may serve as potential therapeutic targets for glioma.  相似文献   
105.
106.
旨在生命机体与危险因子间建立生命物质信息对话平台,以物质化的信息,或信息化的物质的思维进行理解和推论,建立物质承载信息,信息通过物质的形式传递的思维模式,对生命信息中危险因子的属性、分类以及生命机体对危险因子的识别方式进行分析,从以上两个方面不同角度阐述危险因子与生命机体机制信息的相关互动关系。在分析与解读的过程中,主张建立合乎自然生成逻辑的科学概念,而摒弃一些主观是非逻辑所推导建立起来的概念,还原生命物质和生命过程的本来生物学位置及性质;主张一元化的思考方式和整体性理解生命信息安全控制机制的核心部分。分析结果:就生命信息中危险因子的属性和分类进行了分析,指出危险因子具有生命信息属性和生命安全属性两个属性,依据危险因子物质来源的不同,分外源性和内源性两类,绘出危险因子来源分类汇总图;从机体方面对危险因子识别方式不同,分为PRR识别方式和抗原(样)受体识别方式两类,并绘出危险因子识别方式分类汇总图。综合危险因子的属性、分类和生命机体对危险因子的识别方式,绘制出危险因子与生命机体机制信息的相关互动图,从保守性结构信息、生理产物信息、对机体损伤信息、代谢通路信息、对机体变应信息、精细纯外观构象信息及内在性核心信息7个方面对两者的相互关系进行了引证和分析,进一步阐释了生命信息安全控制机制。  相似文献   
107.
我国动物地理学研究的前景─—方法论探讨   总被引:5,自引:0,他引:5  
本文着重从方法论的角度探讨在新形势下我国动物地理学的前景,提出建立两类资料地图──动物学资料图( Zoological information map)和地理学资料图(Geographical information map),以比较地理学分析法(Comparative geographical analysis),进行不同时空尺度的研究,并建议了在最近时期内应优先选择开展研究的关键性地区及其中心问题。  相似文献   
108.
Bennett J  Wakefield J 《Biometrics》2001,57(3):803-812
Pharmacokinetic (PK) models describe the relationship between the administered dose and the concentration of drug (and/or metabolite) in the blood as a function of time. Pharmacodynamic (PD) models describe the relationship between the concentration in the blood (or the dose) and the biologic response. Population PK/PD studies aim to determine the sources of variability in the observed concentrations/responses across groups of individuals. In this article, we consider the joint modeling of PK/PD data. The natural approach is to specify a joint model in which the concentration and response data are simultaneously modeled. Unfortunately, this approach may not be optimal if, due to sparsity of concentration data, an overly simple PK model is specified. As an alternative, we propose an errors-in-variables approach in which the observed-concentration data are assumed to be measured with error without reference to a specific PK model. We give an example of an analysis of PK/PD data obtained following administration of an anticoagulant drug. The study was originally carried out in order to make dosage recommendations. The prior for the distribution of the true concentrations, which may incorporate an individual's covariate information, is derived as a predictive distribution from an earlier study. The errors-in-variables approach is compared with the joint modeling approach and more naive methods in which the observed concentrations, or the separately modeled concentrations, are substituted into the response model. Throughout, a Bayesian approach is taken with implementation via Markov chain Monte Carlo methods.  相似文献   
109.
Long KP  Hu SJ  Duan YB  Xu H 《生理学报》1999,51(5):481-487
本文记录了大鼠损伤背根节神经元的自发放电活动。采用背根节慢性压迫动物模型,记录慢性压迫手术后3-10d背根节的自发放电。在记录的156根纤维中,观察到17根(占11A%)出现的动作电位峰峰间期以某一基础间期的整数倍模式出现的整数倍时间节律形式,其回归映射图为晶格状点阵结构,并且该时间形式受细胞膜上钠,钾通道的调控。  相似文献   
110.
刺激大鼠离断背根外周端对相邻背根电活动的影响   总被引:1,自引:0,他引:1  
Zhang Y  Deng YP  Guan XM 《生理学报》1999,51(4):371-376
在切断大鼠左侧12、13背根后,观察电刺激(刺激参数为0.8-1.2mA,100Hz,0.5ms,总时程2s)L2背根外同对L3背根放电活动的影响。结果表明:连续多次刺激L2背根可使L3背根平均放电频率(MDF)逐步增加,增加量与刺激次数中于明显直线正相关,各次刺激后的时程分析表明,这种增频作用具有明显的累积效应的后效应,并与刺激前13背根的活动状态密切相关,刺激前放电活动较强者其增频作用更明显。  相似文献   
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