Ground state energy of He isoelectronic sequence treated variationally via Hylleraas-like wavefunction

In this study, the energy for the ground state of helium and a few helium-like ions (Z=1-6) is computed variationally by using a Hylleraas-like wavefunction. A four-parameters wavefunction, satisfying boundary conditions for coalescence points, is combined with a Hylleraas-like basis set which explicitly incorporates r12 interelectronic distance. The main contribution of this work is the introduction of modified correlation terms leading to the definition of integral transforms which provide the calculation of expectation value of energy to be done analytically over single-particle coordinates instead of Hylleraas coordinates.

Global transposable characteristics in the complete DNA sequence of the yeast

Global transposable characteristics in the complete DNA sequence of the Saccharomyces cevevisiae yeast is determined by using the metric representation and recurrence plot methods. On the basis of the correlation distance of nucleotide strings, 16 chromosome sequences of the yeast, which are divided into 5 groups, display 4 kinds of the fundamental transposable characteristics: a short increasing period, a long increasing quasi-period, a long major value and hardly relevant.

中药穿龙薯蓣、黄山药和盾叶薯蓣的分子鉴别研究

为建立对中药穿龙薯蓣、黄山药和盾叶薯蓣分子鉴别的方法，我们首先研究薯蓣叶绿体psbA-trnH片段遗传多样性，探讨该片段用于中药穿龙薯蓣、黄山药和盾叶薯蓣种间分子鉴别和系统学研究中的意义。在对不同类群薯蓣种的叶绿体psbA-trnH基因间区进行ＰＣＲ扩增并测序，获得了该区间的完整序列的基础上，将所得序列用软件MEGA3.0进行相关分析。穿龙薯蓣的psbA-trnH片段全长274bp，黄山药全长279bp，盾叶薯蓣植物个体内的叶绿体DNA则有两种psbA-trnH片段，长度分别为241bp和503bp。MEGA3.0软件分析，三种薯蓣种间psbA-trnH片段序列的遗传距离（p-distance）为0.00350-0.04545，各个薯蓣种内的不同类群该序列无差异。用UPGMA法根据psbA-trnH序列的遗传距离建立系统发生树，每个种不同产地的薯蓣很明确地聚在一起，和形态分类一致。所得结果显示psbA-trnH片段序列在所研究的三种薯蓣种内保守，在种间具有明显的较大差异，而三种薯蓣及薯蓣属的系统发生关系尚须进一步研究。 以穿龙薯蓣、黄山药和盾叶薯蓣的psbA-trnH片段序列分析结果为基础，我们根据三种薯蓣在该片段上的特征序列位点设计了用于识别三种薯蓣的寡核苷酸片段并作为PCR反应的引物，将三种薯蓣的特征标记引物与psbA-trnH片段引物配合使用建立了相互识别三种薯蓣的显性和共显性两种检测方式，辅以NaOH碱法快速提取薯蓣干燥根茎总DNA，为三种薯蓣药材相互间快速准确鉴别创造了条件。 To establish molecular method for identifying Chinese medicine Dioscorea nipponica/panthaica/zingiberensis, we firstly study the Genetic diversity of psbA-trnH of Dioscorea and discuss the value of the fragment to molecular identity and systematology to three Dioscorea species (Dioscorea nipponica/panthaica/zingiberensis). The psbA-trnH fragments of different species of Dioscorea are amplified and sequenced，analyzing by software MEGA3.0. The length of Dioscorea nipponica and panthaica are 274bp and 279bp; two psbA-trnH fragments exist in Dioscorea zingiberensis individual, length of the shorter fragment is 241bp and the longer is 503bp. The interspecific Genetic distance (p-distance) of the three species is 0.00350-0.04545, and no intraspecific diversity exists. According to the Genetic distance, phylogenetic tree is built by UPGMA Method, each species of different place gather obviously, which is same to the shape classification. Results show that the psbA-trnH fragment is highly conservative at intraspecific level and obvious diversity at interspecific level, however, phylogenetic study is necessary for the Dioscorea in the future. Based on analysis to psbA-trnH fragment of Dioscorea panthaica, nipponica and zingiberensis, according to the special point of the three Yam species, primers as marker are designed for distinguishing the three species. Cooperating with primer pair psbAf-trnHr, dominant and codominant way is established for discriminating them. Moreover, assisted with NaOH method to extract total DNA of Dry stenophora of Yam, rapid and correct identity to the three species can be done.

Helium isotope investigation on magnetic reversal boundaries of loess-paleosol sequence at Luochuan；central Chinese Loess Plateau

IEECAS SKLLQG