Y chromosome evidence of earliest modern human settlement in East Asia and multiple origins of Tibetan and Japanese populations

Background: The phylogeography of the Y chromosome in Asia previously suggested that modern humans of African origin initially settled in mainland southern East Asia, and about 25,000 30,000 years ago, migrated northward, spreading throughout East Asia. H

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

Mitochondrial genome evidence reveals successful Late Paleolithic settlement on the Tibetan Plateau

Due to its numerous environmental extremes, the Tibetan Plateau -the world's highest plateau-is one of the most challenging areas of modern human settlement. Archaeological evidence dates the earliest settlement on the plateau to the Late Paleolithic, whi

A settlement inhibition assay with cyprid larvae of the barnacle Balanus amphitrite

A settlement inhibition assay using barnacle cyprid larvae, Balanus amphitrite, was developed with Cd2+ and phenol as standard reference toxicants. Mean percentage settlement of cyprid larvae showed a progressive reduction with increasing concentrations of Cd2+ and phenol. A significant reduction in settlement was found when cyprids were exposed to 0.1 mgL(-1) Cd2+ or 10 mgL(-1) phenol. The assay was used to assess the sublethal toxicity of three oil dispersants (Vecom B-1425 GL, Norchem OSD-570 and Corexit 9905) commonly used in Hong Kong waters. Results of this investigation show that the barnacle settlement inhibition assay can be incorporated into the battery of tests currently available for ecotoxicological assessment of marine contaminants. (C) 1997 Elsevier Science Ltd.

Effect of stocking density on growth, settlement and survival of clam larvae, Meretrix meretrix

To determine the optimal larval density for hatchery culture of the clam Meretrix meretrix, experiments with stocking densities of 5, 10, 20, 40 and 60 larvae ml(-1) were designed, which included the developmental stages from D-veliger to 8 days postsettlement. Shell length, settlement time and survival rate of the larvae were recorded. Results showed that, at each sampling time, larvae reared at the highest density had the smallest mean size, whereas larvae reared at the lowest density had the largest mean size. Statistical differences in mean shell length at different stocking densities appeared from day 2, and greater differences occurred with increased culture time. Specific growth rate (SGR) in the rapid growing stage (day 0-3) was negatively correlated with density; however, no correlation was found between SGR and density in the slow growing stage (days 3-7). Settlement time was prolonged and shell length of settled larvae decreased as density increased. However, larval survival rate (74.8-79.1%) was independent of stocking density. Results showed that a high stocking density, in the designated range, is feasible for larval culture of the clam M. meretrix. However, for large-scale culture, in the interest of costs and safety, a stocking density of 10-20 larvae ml(-1) is recommended. (c) 2006 Elsevier B.V. All rights reserved.

The Response of Bucket Foundation under Horizontal Dynamic Loading

The experimental investigation of the response of suction bucket foundation in fine sand layer under horizontal dynamic loading has been carried out. The developments of settlement and excess pore pressure of sand foundation have been mainly studied. It is shown that the sand surrounding the bucket softens or even liquefies at the first stage if the loading amplitude is over a critical value, at later stage, the bucket settles and the sand layer consolidates gradually. With the solidification of the liquefied sand layer and the settlement of the bucket, the movement of the sand layer and the bucket reach a stable state.

Molecular Dynamics Simulation of Barnacle Cement

Barnacle cement is an underwater adhesive that is used for permanent settlement. Its main components are insoluble protein complexes that have not been fully studied. In present article, we chose two proteins of barnacle cement for study, 36-KD protein and Mrcp-100K protein. In order to investigate the characteristic of above two proteins, we introduced the method of molecular modeling. And the simulation package GROMACS was used to simulate the behavior of these proteins. In this article, before the simulations, we introduce some theories to predict the time scale for polymer relaxation. During the simulation, we mainly focus on two properties of these two proteins: structural stability and adhesive force to substrate. First, we simulate the structural stability of two proteins in water, and then the stability of 36-KD protein in seawater environment is investigated.We find that the stability varies in the different environments. Next, to study adhesive ability of two proteins, we simulate the process of peeling the two proteins from the substrate (graphite). Then, we analyze the main reasons of these results. We find that hydrogen bonds in proteins play an important role in the protein stability. In the process of the peeling, we use Lennard–Jones 12-6 potential to calculate the van der Waals interactions between proteins and substrate.