从合作到冲突--简析麦地那时期的阿拉伯-犹太关系

麦地那时期是伊斯兰教发展和阿拉伯国家初创的重要时期。当时已在阿拉伯半岛上相处近千年的阿拉伯和犹太两个民族的关系也经历了从合作到冲突的演变。造成这种演变的主要原因是双方政治经济实力的变化和各自需求的不同,也是伊斯兰教从初创到传播和阿拉伯民族从统一走向扩张的必然结果。犹太人也就成为阿拉伯人征服的第一个“异族”。     

Vesicular restriction of synaptobrevin suggests a role for calcium in membrane fusion

Release of neurotransmitter occurs when synaptic vesicles fuse with the plasma membrane. This neuronal exocytosis is triggered by calcium and requires three SNARE (soluble-N-ethylmaleimide-sensitive factor attachment protein receptors) proteins: synaptobrevin (also known as VAMP) on the synaptic vesicle, and syntaxin and SNAP-25 on the plasma membrane. Neuronal SNARE proteins form a parallel four-helix bundle that is thought to drive the fusion of opposing membranes. As formation of this SNARE complex in solution does not require calcium, it is not clear what function calcium has in triggering SNARE-mediated membrane fusion. We now demonstrate that whereas syntaxin and SNAP-25 in target membranes are freely available for SNARE complex formation, availability of synaptobrevin on synaptic vesicles is very limited. Calcium at micromolar concentrations triggers SNARE complex formation and fusion between synaptic vesicles and reconstituted target membranes. Although calcium does promote interaction of SNARE proteins between opposing membranes, it does not act by releasing synaptobrevin from synaptic vesicle restriction. Rather, our data suggest a mechanism in which calcium-triggered membrane apposition enables syntaxin and SNAP-25 to engage synaptobrevin, leading to membrane fusion.     

Integration of telomere sequences with the draft human genome sequence

Telomeres are the ends of linear eukaryotic chromosomes. To ensure that no large stretches of uncharacterized DNA remain between the ends of the human working draft sequence and the ends of each chromosome, we would need to connect the sequences of the telomeres to the working draft sequence. But telomeres have an unusual DNA sequence composition and organization that makes them particularly difficult to isolate and analyse. Here we use specialized linear yeast artificial chromosome clones, each carrying a large telomere-terminal fragment of human DNA, to integrate most human telomeres with the working draft sequence. Subtelomeric sequence structure appears to vary widely, mainly as a result of large differences in subtelomeric repeat sequence abundance and organization at individual telomeres. Many subtelomeric regions appear to be gene-rich, matching both known and unknown expressed genes. This indicates that human subtelomeric regions are not simply buffers of nonfunctional 'junk DNA' next to the molecular telomere, but are instead functional parts of the expressed genome.     

走近"习性"、"资本"和"场"--读《布尔迪厄访谈录》

布尔迪厄以访谈的形式,阐述了在他的理论体系中起核心组织作用的三个概念"习性"、"资本"和"场".习性是一个构筑在实践层面上的后天获得的性情系统,是在实践中形成的即兴创作的能力.资本是以同一的形式和扩大的形式获取利润的潜在能力,它实质上是权力的一种形式.场涉及的是对人们的关系、地位的分析,对行动者占据的位置的多维空间的阐述;每个场都是斗争的场所.     

分布式PowerBuilder应用程序的调试策略和方法

由于分布式应用的独特性,使得分布式应用程序的调试远比单机应用程序的调试复杂得多。文中对分布式应用程序提出一种“先单机单机程调试,次单机多进程调试,最后再多机远程调试”的调试策略,给出在PowerBuilder开发环境下的实施方法,并对分布式PB应用程序的常用调试工具、技术和调试中应注意的问题进行探讨。所述策略和方法知开发《广西变通高校计算机等级考试管理系统MCT》网络版中得到成功使用,证明是正确可行的。     

教育本质：知识论的困惑与存在论的彰显－兼论教育本质探讨思路的转向

教育本质的论争之所以陷入“疑无路”的境地,根本在于论争只是囿于探究知识论的“教育是什么”而遗忘了追寻存在论的“怎样教育”这一教育之“根”与“本”,以致教育之本质与语言遭际异化。缘此,本文拟在反思以往教育本质论争的基础上,试图走向“怎样教育”,以期扬弃异化,返朴归真。     

伪装检测仿真技术与方法

受时间、设备、经费以及环境等条件的限制,伪装检测实际上不能达到敌现代高技术侦察的条件,处于特例检测以偏概全、满足统计要求的检测又无法实现的两难境遇。通过探索“黑箱化”途径,分析特例与普遍意义的关系,确定统计意义下的应用条件;对连续与间断的辩证转化,建立模拟运算公式和传递模型;讨论局部与整体的空间均匀性,限定模型的边界和条件;由聚类与分解相关因素,简化或深化研究问题;经模拟运行和实验检验,探索实现伪装检测遥感图象的数字仿真。     

塔里木盆地前震旦-石炭纪构造与地层组合特征

通过对塔里木盆地前震旦-石炭纪构造演化与地层组合特征的分析研究,将该盆地构造和地层系统划分为2大组合系统5个构造-地层组合.前震旦系为混合片麻岩、浅变质岩组成的地台基底,震旦纪发生板内裂陷形成坳拉槽,早寒武世-奥陶纪和石炭纪是盆地两次大的海侵期,沉积了富含烃类的碳酸盐岩建造,志留-泥盆纪为克拉通边缘隆升阶段,发育浅海相碎屑岩及碳酸盐岩建造.     

谈高师美术教育的"素质教育"问题

探讨高师美术教育中"素质教育"的相关问题.     

临氢条件下CO偶联合成草酸二乙酯反应的原位红外研究

利用原位红外光谱技术测定了临氢条件下CO和亚硝酸乙酯在催化剂上吸附的红外光谱,发现氢气会影响CO在催化剂活性中心上的吸附,且氢气与CO会发生甲烷化反应,氢气与亚硝酸乙酯反应生成乙醇和少量的乙腈,因此,CO催化偶联反应中加入氢气后,CO的转化率和草酸二乙酯选择性均降低。