Effects of L-aspartic acid,L-asparagine and/or L-asparaginase on forced swimming-induced immobility,analgesia, and decrease in rectal temperature in rats

Summary The effect of L-aspartic acid, L-asparagine and/or L-asparaginase were compared with those of imipramine on immobility, number of defecations, increase of nociceptive threshold, and hypothermia, induced by forced swimming in rats. L-Aspartic acid was found to be as effective as imipramine in reducing the effects of forced swimming, presumable by normalizing the decreased level of endogenous L-aspartic acid, due to the inhibition of L-asparaginase activity and/or by stimulated the inhibited enzyme. The other treatments antagonized the immobility, but not the increased number of defecations. All compounds abolished the elevation of nociceptive threshold and hypothermia.     

氧化铝负载高分散γ—Mo2N的制备及其微观结构的EXAFS表征

采用氧化态Mo/γ－Al2O3与NH3的程序升温反应（TPR）制备了不同Mo担载量的氧化态Mo/γ-Al2O34催化剂,用XRD和EZXAFS方法分别研究了样品在氮化前后的体相结构及Mo原子局域配位结构,结果表明,在氧化前样品的Mo K边径向结构函数与非负载MoO3类似,样品中Mo以高分散的MoO3形式存在,氮化后样品的径向结构函数与非负载的γ－Mo2N基本相同,只是峰强度有所,表明样品中Mo主要以分散度较高的的γ－Mo2N形式存在,并且随担载量降低,γ－Mo2N的分散度更高。     

一种改进BP算法在制冷系统仿真中的应用

采用了改进的BP算法,用网络输出关于学习率的线性展开法来自适应优化学习率,BFGS为尺度法来调整权重,对BFGS法作了局部改进以处理可能发生的BFGS公式中分母项为零的情况,以实际制冷系统的热力性能参数实验数据为样本,对比研究了标准BP算法,含学习率优化的最速下降法和含学习率优化的BFGS法的学习过程,结果表明,文中选用的含学习率优化的BFGS法学习效率与学习精度高,且自适应性能好。     

高阶中立型微分方程振动的充要条件

给出了一类偶数阶微分方程解振动的充要条件。     

白腐菌漂白废水脱色动力学研究

使用Volterra模型描述白腐菌在漂白废水培养基中菌体生长动力学,建立漂白废水脱色部分偶联型动力学方程,初步探讨了生物降解体系中降解菌与发色物质的反应历程,并且利用动力学方法分析了间歇反应时生物降解在漂白废水脱色过程中的作用.     

对社区全民健身活动的调查与对策研究

采用问卷调查和访谈研究方法、针对社区中开展全民健身活动的现状进行分析,找出存在的问题,为促进社区体育活动向深度、广度发展提供依据。     

数字地球与地理信息系统对21世纪地理学的影响

地理信息系统是在2070年代随着计算机技术的发展而兴起的,而数字地球则在20世纪末随着互联网技术以及地理信息系统、遥感技术等信息科学的逐渐成熟而提出的。在对数字地球的概念、关键技术等的研究和对地理信息系统的空间思维和空间可视化及地理信息系统的发展趋势研究的基础上,探讨了在21世纪这两门新技术对地理这门古老学科在研究方法和研究理论上要产生的作用。     

三个典型问题的回溯算法

介绍了排列问题、组合问题和皇后问题的回溯算法,对《算法设计与分析》课程的学习以及参加“大学生数学建模竞赛”与“中学生奥林匹克信息学（计算机）竞赛”等具有一定指导意义。     

New bisexual form of Cavernocypris subterranea (Wolf, 1920) (Crustacea, Ostracoda) from Idaho

Males of Cavernocypris subterranea were found for the first time in an Idaho spring. The bisexual form is described on soft body parts and valves. The genus Cavernocypris now includes 2 bisexual and 1 parthenogenteic species.     

Using Firm‐Level Leverage as an Investment Strategy

We use an investment strategy based on firm‐level capital structures. Investing in low‐leverage firms yields abnormal returns of 4.43% per annum. If an investor holds a portfolio of low‐leverage and low‐market‐to‐book‐ratio firms, abnormal returns increase to 16.18% per annum. A portfolio of low leverage and low market risk yields abnormal returns of 6.67% and a portfolio of small firms with low leverage earns 5.37% per annum. We use the Fama‐Macbeth (1973) methodology with modifications. We confirm that portfolios based on low leverage earn higher returns in longer investment horizons. Our results are robust to other risk factors and the risk class of the firm. Copyright © 2011 John Wiley & Sons, Ltd.