Global distribution of Y-chromosome haplogroup C reveals the prehistoric migration routes of African exodus and early settlement in East Asia

The regional distribution of an ancient Y-chromosome haplogroup C-M130 (Hg C) in Asia provides an ideal tool of dissecting prehistoric migration events. We identified 465 Hg C individuals out of 4284 males from 140 East and Southeast Asian populations. We genotyped these Hg C individuals using 12 Y-chromosome biallelic markers and 8 commonly used Y-short tandem repeats (Y-STRs), and performed phylogeographic analysis in combination with the published data. The results show that most of the Hg C subhaplogroups have distinct geographical distribution and have undergone long-time isolation, although Hg C individuals are distributed widely across Eurasia. Furthermore, a general south-to-north and east-to-west cline of Y-STR diversity is observed with the highest diversity in Southeast Asia. The phylogeographic distribution pattern of Hg C supports a single coastal 'Out-of-Africa' route by way of the Indian subcontinent, which eventually led to the early settlement of modern humans in mainland Southeast Asia. The northward expansion of Hg C in East Asia started similar to 40 thousand of years ago (KYA) along the coastline of mainland China and reached Siberia similar to 15 KYA and finally made its way to the Americas. Journal of Human Genetics (2010) 55, 428-435; doi:10.1038/jhg.2010.40; published online 7 May 2010

Differential cognitive responses to guqin music and piano music in Chinese subjects: an event-related potential study

目的 研究古琴(一种古老的中国乐器)和钢琴音乐对认知的影响.方法 记录和分析了中国被试在两种音乐背景(古琴音乐,钢琴音乐)下完成听觉oddball任务的行为和事件相关电位(event-related potential,ERP)数据.结果 中国被试在本土文化的音乐环境(古琴音乐)下,前额区诱导出更大的P300,这一结果和已有的相关研究是相符的.同时,不同音乐背景对ERP产生的影响在N1和LPC(包括P300和P500)上也表现出差别:中国被试在古琴音乐背景下比钢琴音乐背景下表现出更多的右前侧颞叶的参与.结论 因为古琴音乐的五声调式和汉语发音的音调具有对应关系,因此我们推断在古琴音乐下所表现出的这种特性与被试的汉语环境有关.

The photorefractive sensitivity and the effective electron transport length in two-centre holographic recording

In this paper the photorefractive sensitivity defined for single-centre holographic recording is modified to adapt two-centre holographic recording. Based on the time analytic solution of Kukhtarev equations for doubly doped crystals, the analytical expression of photorefractive sensitivity is given. For comparison with single-centre holographic recording and summing the electron competition effects between the deeper and shallower traps, an effective electron transport length is proposed, which varies with the intensity ratios of recording light to sensitive light. According to analyses in this paper, the lower photorefractive sensitivity in two-centre holographic recording is mainly due to the lower concentration of unionized dopants in the shallower centre and the lower effective electron transport length.