城市地理信息三维可视化研究

讨论的城市地理信息系统三维可视化技术致力于将传统的地理信息系统和虚拟现实技术结合起来，通过对图形数据和属性数据库的共同管理、分析及操作，实现数据可视化，为城市管理和决策提供准确、及时、全面的信息、依据和手段，促进城市管理的规范和科学化。本文建立的三维可视化城市地理信息系统使用了细节层次(Level of Detail，LOD)显示技术和视景分块调度技术来提高实时性。     

食饵种群具有常数放养的Ⅱ型功能反应捕食系统的定性分析

考虑食饵种群具有常数放养的Holling Ⅱ型功能反应捕食系统 x=(r—bx)x—yφ(x)+k y=y(-d+eφ(x))这里φ(x)=(ax)/(1+ωx)为Holling Ⅱ型功能反应函数,k>0是食饵种群的常数放养率。1 平衡点的性质及其稳定性经无量纲变换,系统(1)化为     

基于思维进化算法的常微分方程组演化建模

在基本思维进化算法（MindEvolutionaryComputation，原名Mind-Evolution-BasedMachineLearning）框架的基础上，吸取遗传规划（GP）中的树形编码思想，提出了利用树结构进行信息抽取的方法，进而实现了用于常微分方程组演化建模的趋同、异化算子，并获取了优良的效果，使MEC在非数值优化领域中得到了进一步应用。最后的仿真实例的结果表明，同GP方法比较，MEC方法具有计算速度快、建模结果优和全局搜索性能好等明显优点。     

耦合标量场中孤子激发与耦合参数之间的关系

本文提供一个简捷的方法求解相对论性的耦合标量场中的精确孤子解,并考察了其孤子解与耦合参量d之间的关系,此方法可以用来求解其他类型的非线性耦合方程及类似的非线性微分方程.     

A single population of olfactory sensory neurons mediates an innate avoidance behaviour in Drosophila

All animals exhibit innate behaviours in response to specific sensory stimuli that are likely to result from the activation of developmentally programmed neural circuits. Here we observe that Drosophila exhibit robust avoidance to odours released by stressed flies. Gas chromatography and mass spectrometry identifies one component of this 'Drosophila stress odorant (dSO)' as CO2. CO2 elicits avoidance behaviour, at levels as low as 0.1%. We used two-photon imaging with the Ca2+-sensitive fluorescent protein G-CaMP to map the primary sensory neurons governing avoidance to CO2. CO2 activates only a single glomerulus in the antennal lobe, the V glomerulus; moreover, this glomerulus is not activated by any of 26 other odorants tested. Inhibition of synaptic transmission in sensory neurons that innervate the V glomerulus, using a temperature-sensitive Shibire gene (Shi(ts)), blocks the avoidance response to CO2. Inhibition of synaptic release in the vast majority of other olfactory receptor neurons has no effect on this behaviour. These data demonstrate that the activation of a single population of sensory neurons innervating one glomerulus is responsible for an innate avoidance behaviour in Drosophila.     

Control of phyllotaxy by the cytokinin-inducible response regulator homologue ABPHYL1

Phyllotaxy describes the geometric pattern of leaves and flowers, and has intrigued botanists and mathematicians for centuries. How these patterns are initiated is poorly understood, and this is partly due to the paucity of mutants. Signalling by the plant hormone auxin appears to determine the site of leaf initiation; however, this observation does not explain how distinct patterns of phyllotaxy are initiated. abphyl1 (abph1) mutants of maize initiate leaves in a decussate pattern (that is, paired at 180 degrees), in contrast to the alternating or distichous phyllotaxy observed in wild-type maize and other grasses. Here we show that ABPH1 is homologous to two-component response regulators and is induced by the plant hormone cytokinin. ABPH1 is expressed in the embryonic shoot apical meristem, and its spatial expression pattern changes rapidly with cytokinin treatment. We propose that ABPH1 controls phyllotactic patterning by negatively regulating the cytokinin-induced expansion of the shoot meristem, thereby limiting the space available for primordium initiation at the apex.     

重组人甲状旁腺激素(1-34)在大肠杆菌中的表达与纯化

将化学合成的rhPTH(1-34)基因用PCR扩增后,克隆至表达载体pET-35b( ),使rhPTH(1—34)融合于纤维素结合结构域(CBDdos)的羧基端,并得到高效表达．融合蛋白经纤维素树脂亲和层析纯化后,经Factor Xa裂解释放出rhPTH(1-34),再通过纤维素树脂亲和层析、C4反向高效液相色谱纯化得到rhPTH(1-34)纯品．每升培养液可获取3mg高纯度的rhPTH(1-34)．经质谱测定,所得样品的分子量为4117．0Da,与rhPTH(1—34)理论分子量一致．     

重组人脑钠素在大肠杆菌中的表达、纯化与鉴定

人脑钠素(hBNP,humanbrainnatriureticpeptide)是心室分泌的由32个氨基酸组成的多肽激素.临床研究表明,hBNP是治疗充血型心衰竭的一种安全有效的多肽药物.化学合成脑钠素全基因,以pET32a为表达载体,构建了硫氧还蛋白-脑钠素(thioredoxin＿hBNP)融合蛋白表达质粒,并转化至大肠杆菌BL21(DE3),经IPTG诱导,融合蛋白的表达量占全菌蛋白量的25%以上.融合蛋白经肠激酶裂解、Zn＿Sepharose亲和层析和C4反相高效液相层析,从每升培养液中可获取4mgrhBNP,纯度达到95%.经质谱测定,rhBNP样品的分子量为3464Da.体外活性测定结果表明,rhBNP样品对兔胸主动脉条具有显著的血管舒张效应,其ED50为(2.24±0 58)×10-6mg/mL.     

重组人胸腺肽α1在大肠杆菌中的表达纯化和鉴定

用PCR将化学合成的人胸腺肽α1基因扩增并克隆到pMD18-T载体中,经过KpnI／SacI酶切、连接将胸腺肽基因插入到表达载体pET32b中硫氧还蛋白下游．将重组质粒转化至表达宿主BL21(DE3)中,经IPTG诱导,Zn—Sepharose亲和层析纯化以及复性处理,从每升菌液中可获得35mg硫氧还蛋白-胸腺肽α1融合蛋白．经凝血因子Xa酶切、Zn—Sepharose亲和层析以及反相高效液相色谱纯化获得3．8mg重组人胸腺肽．小鼠胸腺细胞凋亡实验表明,重组人胸腺肽能显地抑制地赛米松诱导的小鼠胸腺细胞的凋亡,且该抑制作用与重组人胸腺肽的浓度呈剂量依赖关系．