自适应SAGA算法进行全局寻优的研究

遗传算法以概率转换规则为基础,在给定问题的潜在解集中进行广泛搜索,具有很强的全局寻优能力,但收敛速度慢。模拟退火算法理论上只要计算时间足够长,就可以保证收敛于全局最优点。但是在实际算法的实现过程中,由于计算速度和时间的限制,全局寻优点的效果并不理想。将遗传算法和模拟退火相结合,提出一种混合的自适应遗传算法,可以提高收敛速度并改善全局寻优性能。     

Cloning and structure of a yeast gene encoding a general transcription initiation factor TFIID that binds to the TATA box

The TATA sequence-binding factor TFIID plays a central role both in promoter activation by RNA polymerase II and other common initiation factors, and in promoter regulation by gene-specific factors. The sequence of yeast TFIID, which seems to be encoded by a single gene, contains interesting structural motifs that are possibly involved in these functions, and is similar to sequences of bacterial sigma factors.     

成人乙状结肠冗长症的诊断和治疗

目的乙状结肠冗长症是导致成人便秘的主要原因之一，为提高对该病的诊治水平进行探讨、方法通过5a来收治的15a例成人乙状结肠冗长症的临床资料进行总结，结果术后随访1～5a，均获满意结果，结论成人乙状结肠冗长症的诊断主要靠钡剂灌肠，治疗上首选非手术疗法，无效时，可行乙状结肠部分切除术.     

基于全局转录工程促进肺炎克雷伯氏菌吡咯喹啉醌的生物合成

用易错PCR构建肺炎克雷伯氏菌(Klebsiella pneumoniae)RNA聚合酶rpoD基因的突变文库,将其与载体连接后转化肺炎克雷伯氏菌,从1500个阳性克隆中筛选出一株吡咯喹啉醌(PQQ)生产菌。发酵试验表明,该工程菌的PQQ产量为76mg/mL,比携带未突变rpoD基因的对照菌提高了10%。测序发现rpoD基因在核酸和蛋白质水平的突变率分别达到2.5%和0.5%。二级结构预测发现α螺旋、β转角和无规则卷曲数目均发生了变化,推测由此改变了σ因子与启动子的亲和程度,从而导致了PQQ基因的转录以及K. pneumoniae代谢流量再分配,使得PQQ得到更高效表达。     

A systematic survey of PRMT interactomes reveals the key roles of arginine methylation in the global control of RNA splicing and translation

Thousands of proteins undergo arginine methylation,a widespread post-translational modification cat-alyzed by several protein arginine methyltransferases(PRMTs)...     

Mechanisms for the hiatus in global warming

The observed global mean temperature is the highest on record for the past decade but has plateaued to form an apparent ＂hiatus＂ in global temperature rise, with an almost zero short-term trend. Several speakers presented results on the hiatus and suggested possible mechanisms.     

高校富余人员思想政治工作初探

高等学校人事管理体制改革的最大难点是解决富余人员的分流问题，如何使富余人员认清形势，面对现实，理解和支持改革，是做好富余人员思想政治工作关系，做好富余人员的思想政治工作的有效途径主要有：1，正确把握不同层次富余人员的现实需求，使思想政治工作具有针对性；2，努力营造良好的舆论氛围，使思想政治工作具有亲和性；3，加强人力资源开发，使思想政治工作具有实效性；4，不断改善政策环境，使思想政治工作更具引导性。     

利用增广雅克比矩阵的冗余机械臂逆运动学求解算法

针对冗余机械臂逆运动学问题,提出了一种利用增广雅可比矩阵的逆运动学求解算法.首先,将优化给定的目标函数作为约束任务对机械臂的任务空间进行增广,在此基础上构造增广雅克比矩阵.然后采用分解计算策略将增广部分分解,分别计算后,得到其数值结果.进而利用增广雅可比矩阵计算出关节速度,对其积分后获得关节位置.最后,将本文方法应用于...     

Direct and selective binding of an acidic transcriptional activation domain to the TATA-box factor TFIID

The potent transactivation domain of the herpes simplex virion protein VP16 was used as a column ligand for affinity chromatography. VP16 binds strongly and highly selectively to the human and yeast TATA box-binding factors. Our results imply that the principal target for acidic activation domains is the TATA-box factor TFIID.     

冗余度机器人速度及力传递性能的度量方法

在速度和力可操作椭球的基础上,定义了冗余度机器人机构速度和力方向的可操作度．利用速度和力方向可操作度,度量机器人在当前位形状态下沿指定方向速度和力的传递能力,并通过优化,确定速度和力的最佳传递方位和最佳操作位形．算例表明,平面冗余度机器人机构在给定位形条件下,传力性能强(弱)的方向上传速的性能弱(强)。     

Computational roles for dopamine in behavioural control

Neuromodulators such as dopamine have a central role in cognitive disorders. In the past decade, biological findings on dopamine function have been infused with concepts taken from computational theories of reinforcement learning. These more abstract approaches have now been applied to describe the biological algorithms at play in our brains when we form value judgements and make choices. The application of such quantitative models has opened up new fields, ripe for attack by young synthesizers and theoreticians.     

冗余CAN总线在MDCS系统上的设计与实现

为了提高控制系统在网络通信上的可靠性和稳定性,基于MDCS系统提出CAN总线的冗余设计.研究了MDCS2001系统的技术原理及冗余CAN总线的硬件设计方案,包括总线结构图和控制接线图.经过兀X组态软件的组态.实现了冗余CAN总线的监控、自动换线、检测等功能,将其应用到各种生产过程的自动化控制中,可以提高信息传送的可靠性和生产过程的安全性.     

Proposal and prospects for the global Lower-Middle Cambrian boundary

In recent years paleontologists have been working on the global stratotype section and standard point (GSSP) for the Lower-Middle Cambrian boundary in North America, China, Morocco, Spain and Russia. Continually, they suggest the potential first appearance datum (FAD) of the Middle Cambrian, such as Oryctocephalus indicus, Ovatoryctocara granulata, Acadoparadoxides mureroensis, Hupeolenus and Arthricocephalus chauveaui as being relevant to the potential stratotype section for the Lower-Middle Cambrian boundary. There are only a few trilobites distributed widely enough in the Early to Middle Cambrian connection, so virtually no trilobite(s) can act as the FAD for the global Middle Cambrian. The easily identified Oryctocephalus indicus is widely distributed in three realms of the global Cambrian. Its first appearance position is linked to the extinction of old species coevolution of new ones. It appears to be a comparatively good FAD of Middle Cambrian. The continuous and unbroken Wuliu section (Balang, Taijiang County, Guizhou Province, China) includes O. indicus and co-occurs with many benthic and nektonic trilobites. The evolution of acritarchs in the section, the changed characteristics of trace elements (REE and C isotopes) are generally consistent with the evolution of trilobites both above and below the boundary. Strata above the boundary yield the famous Kaili Biota. The Wuliu section is easily accessible from a main highway.     

解决冗余机器人伪逆可积性问题的势函数法

用伪逆求解具有冗余特性机器人关节空间的运动存在不可预测性，这是由其雅可比矩阵伪逆不可积造成的，结果直接影响机器人的轨迹规划．通过针对伪逆不可积问题的现象及其影响的分析，指出了此类问题的实质及解决问题的途径，在此基础上提出了处理问题的具体方法─—势函数法．实例仿真验证了势函数法的可行性．     

Two roles for guanine nucleotides in the stimulus-secretion sequence of neutrophils

The term 'stimulus-secretion coupling' has, since first enunciated, been held to involve the mobilization of cytosol Ca2+, which in turn is sufficient to trigger exocytotic secretory processes in metabolically competent cells. However, recent studies on a wide range of secretory cell types indicate that a role for Ca2+ can be obviated: examples are stimulation with phorbol ester (phorbol myristate acetate, PMA) which causes the activation of protein kinase C or the stimulation of platelets with collagen. Ca2+-independent exocytosis also occurs when analogues of GTP are injected through the lumen of patch pipettes directly into the cytosol of mass cells. The results presented here suggest that GTP analogues can activate secretory processes by actions at two distinct locations: one may be at the level of the receptor involving the activation of polyphosphoinositide (PPI) phosphodiesterase with consequent liberation of diacylglycerol (DG); the other involves direct activation of the exocytotic mechanism. These conclusions are based on measurements of exocytotic secretion from permeabilized neutrophils into which we have been able to introduce, individually and in combination, Ca2+ chelators (EGTA and BAPTA), Ca2+ (buffered at micromolar concentrations with EGTA), analogues of GTP and GDP and the direct activator of protein kinase C, PMA.     

一类波动方程整体解的存在性与不存在性

研究了一类具有异号项的高阶波动方程初边值问题.首先介绍了这类方程的最新研究进展,并引入了几个重要的广义泛函和集合,然后讨论了这些泛函的性质,并证明了这些集合在该波动方程下是不变的.最后利用Galerkin逼近法和位势井法相结合证明了方程整体弱解的存在性,并利用位势井-凸性方法分析了方程整体弱解不存在的前提条件.同时给出了方程整体弱解存在与不存在的最佳门槛结果.     

一种新颖的冗余度机器人及其视觉伺服方案

视觉伺服冗余度机器人在灵巧操作、装配等领域有很好的应用前景 .为了减少其运动规划的计算量 ,设计了一种具有准万向关节的七自由度机械臂结构 .在此基础上提出了一种基于位姿分散自律速度控制的运动规划方法 :采用速度矢量极小最小二乘分解方法进行腕部运动速度控制 ;根据欧拉角法则正向递推解决操作手的姿态规划问题 .文中还采用数值仿真手段验证了其有效性 .该方法的特点是物理意义明确 ,算法简单 .同时具有一定的运动学鲁棒性 .