香格里拉区域大气本底站环境特征初探

介绍了香格里拉大气本底站的站址地理分布特征,分析和总结了近年来的基本气象要素特征,通过轨迹-聚类方法分析了影响该站的气流来源.轨迹分析结果表明:香格里拉区域大气本底观测站对于探讨南亚地区的大气成分远距离输送对我国西南地区的环境影响具有独特的作用.     

Crystal structure of the β2 adrenergic receptor-Gs protein complex

G protein-coupled receptors (GPCRs) are responsible for the majority of cellular responses to hormones and neurotransmitters as well as the senses of sight, olfaction and taste. The paradigm of GPCR signalling is the activation of a heterotrimeric GTP binding protein (G protein) by an agonist-occupied receptor. The β(2) adrenergic receptor (β(2)AR) activation of Gs, the stimulatory G protein for adenylyl cyclase, has long been a model system for GPCR signalling. Here we present the crystal structure of the active state ternary complex composed of agonist-occupied monomeric β(2)AR and nucleotide-free Gs heterotrimer. The principal interactions between the β(2)AR and Gs involve the amino- and carboxy-terminal α-helices of Gs, with conformational changes propagating to the nucleotide-binding pocket. The largest conformational changes in the β(2)AR include a 14 ? outward movement at the cytoplasmic end of transmembrane segment 6 (TM6) and an α-helical extension of the cytoplasmic end of TM5. The most surprising observation is a major displacement of the α-helical domain of Gαs relative to the Ras-like GTPase domain. This crystal structure represents the first high-resolution view of transmembrane signalling by a GPCR.     

The Moment of China's Internet Companies Management Method

文章介绍了我国互联网企业的资本结构后,从市场、技术、人力资源3个方面分析了我国互联网企业的管理之道,最后讨论了互联网企业文化建设的不足和原因.以及如何提高策略.     

Identification of susceptibility genes loci associated with type 2 diabetes

In this study, we selected 10 susceptible SNPs loci to investigate their contribution to susceptibility to type 2 diabetes in Han Chinese among Hubei population. We genotyped SNPs rs5219, rs1801282, rs1470579, rs1111875, rs1081661, rs7754840, rs4506565, rs13266634, rs4402960, and rs5643981 by using the method of polymerase chain reaction-ligase detection reaction (PCR-LDR). In a case-control study, we have genotyped the 10 candidate susceptibility SNP loci, and here, we reported that the SNP rs5219 in KCNJ1...     

天文学在古代中国社会文化中的作用

从天人关系的角度探讨了中国古代天文学在社会文化中的作用.中国古代天文学从早期开始就与敬天的宗教崇拜密不可分.天文观测既是敬天的活动.也是"通天"的手段.历法对于农业社会来说无疑是十分重要的,因此"观象授时"成为帝王统治的首要政治任务.历法是"君权神授"的"天命"的象征.改革历法就意味着改变天命,是重大的宗教政治问题.从敬天和观天的宗教天文活动中产生了"法天"的思想.帝王只要按照历法规定的"月令"治理国家,社会就和谐有序.汉代的董仲舒提出"天人合一"的宗教神学思想,把天文现象当作灾异现象,具有警示人事的作用.以观天象而占国家大事吉凶的中国占星术因此在中国古代宗教政治中发挥了极其重要的作用.     

基于Pro/E的车用CNG气瓶装卸机械设计

针对车用CNG气瓶定检时人工装卸气瓶效率低、安全性差等问题,提出设计一种CNG气瓶装卸机械.该装置包括升降小车和机械抓手两部分,可实现对气瓶的抓取、旋转、升降、进退等动作.基于Pro/Engineer的三维建模功能,建立该机械装置、气瓶及车厢的3D模型,进行模拟装卸的结构干涉分析.结果表明该机械结构简单、操作方便,具有...     

微合金非调质40Mn2V钢管的变形抗力研究

采用Gleeble-1500 热模拟实验机对微合金非调质40Mn2V钢管的变形抗力进行了研究.结果表明,变形温度越高,变形速率越低,钢管变形抗力越小.变形抗力对数值lnσ随着温度升高和变形速率对数值lnε·的增大,分别呈线性减小和线性增大,且变形抗力与变形程度呈非线性关系.采用Matlab软件拟合出了微合金非调质40Mn2V钢管的变形抗力公式,其拟合度R为0.966 3.     

析当前我国大学生失业的特点

大学生失业从历史和世界的角度来考察,是一种比较普遍的社会现象。1999年高校扩招之后,我国开始出现了比较突出的大学生失业现象,并引起了人们的高度关注。当前我国大学生的失业现象具有必然性和合理性、主动性和被动性、相对性、差异性等特点,分析这些特点有助于我们全面地辩证地认识大学生失业现象。     

Medical entity and attributes extraction system based on relation annotation

The abundant entities and entity-attribute relations in medical websites are important data resources for medical research. However, the medical websites are usually characterized of storing entity and attribute values in different pages. To extract those data records efficiently, we propose an automatic extraction system which is related to entity and attribute relations (attributes and values) of separate storage. Our system includes following modules: (1) rich-information interactive annotation page rendering; (2) separate storage attribute relations annotating; (3) annotated relations for pattern generating and data records extracting. This paper presents the relations about the attributes which are stored in many pages by effective annotation, then generates rules for data records extraction. The experiments show that the system can not only complete attribute relations of separate storage extraction, but also be compatible with regular relation extraction, while maintaining high accuracy.     

重新解读网络环境下的文件生命周期理论

文件连续体理论与文件生命周期理论之争,其主因是档案学界对两种理论定位和电子文件生命周期的认识不一.本文对此从一切文件皆有生命周期、电子文件生命周期表现形式与纸质文件生命周期表现形式比较、科学认识网络环境下的文件生命周期理论三方面,运用辩证唯物史观重新解读网络环境下的文件生命周期理论.