Effects of maternal aging on localizations and expression levels of DNA methyltransferases and chromosome architecture in in-vivo matured mouse oocytes

This paper investigated the age-related changes in the expression patterns of maintenance methyltransferase (DNMT1) and de novo methyltransferases (DNMT3a, 3b, 3L) and the chromosome architecture in in-vivo matured mouse oocytes using two-photon laser-scanning microscope. Our results showed that (1) DNMT1 and DNMT3a, 3b, 3L in the oocytes of pubertal mice were located in the cortical region of oocyte cytoplasm. In aging groups, DNMT1 was also located in the cortical region. However, DNMT3a, 3b, 3L had a relatively wider distribution in the oocyte cytoplasm and appeared near the chromosomes. These differences between pubertal and aging groups suggested that aging might affect DNA methylation; (2) the expression of DNMT1, and DNMT3a, 3b in aging groups increased significantly compared to pubertal groups, while, the expression of DNMT3L decreased. These results might be explained by the compensation mechanism among DNMTs, which might be impervious to aging; (3) aging caused increased errors in the distribution and three-dimensional morphology of chromosomes, including the increased total volume and surface area, the high ratio of height to diameter of a circular cylinder enclosing the chromosomes (H/D). Our work provided morphological information for the studies of age-related decline in oocyte qualities.     

狭窄光学共振的飞秒脉冲激光稳频性研究

稳频的连续飞秒脉冲激光器以狭窄的光学共振作为水准基点，这种激光器具有稳定频率成分的宽带光谱和大功率的超短脉冲，能够有效的快速转变频率。在本文中可以看出这种双光子吸收共振使氢原子1S-2S能级之间跃迁的钛宝石激光器稳频飞秒脉冲振荡机制。     

Gabor和小波框架

Gabor分析和小波分析在信号分析、图像处理和其它信息科学领域有着广泛的应用，二者都适合描述时频信号的局部特征，与传统的Fourier分析描述的稳定信号相比它们具有极大的灵活性和实用性。     

非交换几何导论

非交换几何对于大多数数学家来讲，是一个陌生的概念。它不仅是当代数学的最前沿，而且涉及所有布尔巴基数学的交叉，即使这些数学也不是简单的：测度论、代数拓扑学、算子代数、微分拓扑学、微分（黎曼）几何学……，更让数学家头痛的还包括整套的量子物理学。     

光学测量技术

本书是施普林格出版社的光学科学系列丛书的136卷，作者佩波宁教授于1977年、1979年分别在约恩苏大学获得学士和硕士学位，1982年在约恩苏大学获得博士学位，此后一直在约恩苏大学从事教学和科研工作，长期从事光学测量方面的研究工作。     

Attributes associated with probability of infestation by the pi?on ips, Ips confusus (Coleoptera: Scolytidae), in pi?on pine, Pinus edulis

We examined attributes of pi?on pine ( Pinus edulis ) associated with the probability of infestation by pi?on ips ( Ips confuses ) in an outbreak in the Coconino National Forest, Arizona. We used data collected from 87 plots, 59 infested and 28 uninfested, and a logistic regression approach to estimate the probability of infestation based on plot and tree-level attributes. Pi?on pine stand density index was a good predictor of the likelihood of infestation by pi?on ips at the plot level, and a cross-validation analysis confirmed that the model correctly classified 82% of the cases. Diameter at root collar and pi?on dwarf mistletoe infestation level were good predictors of individual tree infestation, and a cross-validation analysis indicated that the model correctly classified 72% of the cases. Results suggest that the occurrence of pi?on ips infestations may be related to stress factors associated with increased stocking and pi?on dwarf mistletoe infestations.     

Global awareness, future city design and decision making

Our world has been changing at an exponential rate.As a result of this rapid growth,we will be forced to make changes in not only the way we live in the environment but also in the environment itself such as designing the cities of the future to be in greater harmony with the increasing population and growing complexity.The paper contains both reflections on global awareness and comprehensive criteria and their priorities for choosing the most desirable city.     

考虑轴颈偏斜时滑动轴承的动力特性

本文建立了同时考虑轴颈径向位移和歪斜时的滑动轴承动力学模型.对于这种模型,油膜力将扩展为四个广义力分量.文章将相应的动力系数矩阵分解为对称和反对称两部分并讨论其物理性质.然后,本文推导得出该模型的正交变换矩阵,在此基础上导得各向同性的动力系数矩阵表达式,并讨论了诸元素的物理意义.文章最后引入动力系数椭圆的概念以分析非对称动力系数矩阵的变换性质.     

煤层注水效果的数量化理论预测法与参数的修正

本文应用数量化理论，给出了如何建立煤层注水效果的预测数学模型，并结合实例，进行了预测．实例表明，根据本矿已知煤层注水工程的各种信息，采用数量化理论．建立的计算机预测煤层注水效果的方法，不仅可以确切地判定所给定的注水组合参数是否最优，同时还揭露了注水参数与水分增值的内在关系，为调控参数提供了科学手段