Evolutionary history of the mtDNA 9-bp deletion in Chinese populations and its relevance to the peopling of east and southeast Asia

In total, 1218 Chinese from twelve ethnic groups and nine Han geographic groups were screened for the mtDNA 9-bp deletion motif. The frequency of the 9-bp deletion in all samples was 14.7% but ranged from 0% to 32% in the various ethnic groups. Three individuals had a triplication of the 9-bp segment. Phylogenetic and demographic analyses of the mtDNA hypervariable segment 1 (HVS1) sequences suggest that the 9-bp deletion occurred more than once in China. The majority of the Chinese deletion:haplotypes (about 90%) have a common origin as a mutational event following an initial expansion of modem humans in eastern Asia. Other deletion haplotypes and the three haplotypes with a 9-bp triplication may have arisen independently in the Chinese, presumably by replication error. HVS1 haplotype analysis suggests two possible migration routes of the 9-bp deletion in east and southeast Asia. Both migrations originated in China with one route leading to the Pacific Islands via Taiwan, the other to southeast Asia and possibly the Nicobar Islands. Along both routes of peopling, a decrease in HVS1 diversity of the mtDNA haplotypes is observed. The "Polynesian motif (16217T/C, 16247A/G, and 16261C/T)" and the 16140T/C, 16266C/A, or C/G polymorphisms appear specific to each migration route.

Frequency of the mtDNA 9-bp deletion in Chinese ethnic groups

The 9-bp deletion in the COII/tRNA(Lys) intergenic region (region V) of human mitochondrial DNA was screened in 1521 Chinese from 16 ethnic groups and 9 Hen geographic groups. The highest frequency was found in populations of Miao (32.4%) and Bouyei (30.8

The Acquisition of an Inheritable 50-bp Deletion in the Human mtDNA Control Region Does Not Affect the mtDNA Copy Number in Peripheral Blood Cells

The mitochondrial DNA (mtDNA) control region is believed to play an important biological role in mtDNA replication. Large deletions in this region are rarely found, but when they do occur they might be expected to interfere with the replication of the molecule, thus leading to a reduction of mtDNA copy number. During a survey for mtDNA sequence variations in 5,559 individuals from the general Chinese population and 2,538 individuals with medical disorders, we identified a 50-bp deletion (m.298_347del50) in the mtDNA control region in a member of a healthy Han Chinese family belonging to haplogroup B4c1b2, as suggested by complete mtDNA genome sequencing. This deletion removes the conserved sequence block II (CSBII; region 299-315) and the replication primer location (region 317-321). However, quantification of the mtDNA copy number in this subject showed a value within a range that was observed in 20 healthy subjects without the deletion. The deletion was detected in the hair samples of the maternal relatives of the subject and exhibited variable heteroplasmy. Our current observation, together with a recent report for a benign 154-bp deletion in the mtDNA control region, suggests that the control of mtDNA replication may be more complex than we had thought. Hum Mutat 31:538-543, 2010. (C) 2010 Wiley-Liss, Inc.

Geographic variation of the Perny's Long-nosed squirrels (Dremomys pernyi) (Milne-Edwards, 1867) (Rodentia : Sciuridae) from southwestern China based on cranial morphometric variables

A sample of 114 specimens of Dremomys pernyi was investigated, 73 of which had intact skulls and were subjected to multivariate, coefficient of difference (C. D.), and cluster analyses. Results indicate that 4 subspecies (groups) of Dremomys pernyi inhabi

A priori assessment of algebraic flame surface density models in the context of large eddy simulation for nonunity lewis number flames in the thin reaction zones regime

The performance of algebraic flame surface density (FSD) models has been assessed for flames with nonunity Lewis number (Le) in the thin reaction zones regime, using a direct numerical simulation (DNS) database of freely propagating turbulent premixed flames with Le ranging from 0.34 to 1.2. The focus is on algebraic FSD models based on a power-law approach, and the effects of Lewis number on the fractal dimension D and inner cut-off scale η i have been studied in detail. It has been found that D is strongly affected by Lewis number and increases significantly with decreasing Le. By contrast, η i remains close to the laminar flame thermal thickness for all values of Le considered here. A parameterisation of D is proposed such that the effects of Lewis number are explicitly accounted for. The new parameterisation is used to propose a new algebraic model for FSD. The performance of the new model is assessed with respect to results for the generalised FSD obtained from explicitly LES-filtered DNS data. It has been found that the performance of the most existing models deteriorates with decreasing Lewis number, while the newly proposed model is found to perform as well or better than the most existing algebraic models for FSD. © 2012 Mohit Katragadda et al.

The effects of non-unity lewis numbers on turbulent premixed flame interactions in a twin V-flame configuration

The influence of Lewis number on turbulent premixed flame interactions is investigated using automatic feature extraction (AFE) applied to high-resolution flame simulation data. Premixed turbulent twin V-flames under identical turbulence conditions are simulated at global Lewis numbers of 0.4, 0.8, 1.0, and 1.2. Information on the position, frequency, and magnitude of the interactions is compared, and the sensitivity of the results to sample interval is discussed. It is found that both the frequency and magnitude of normal type interactions increases with decreasing Lewis number. Counternormal type interactions become more likely as the Lewis number increases. The variation in both the frequency and the magnitude of the interactions is found to be caused by large-scale changes in flame wrinkling resulting from differences in the thermo-diffusive stability of the flames. During flame interactions, thermo-diffusive effects are found to be insignificant due to the separation of time scales. © 2013 Copyright Taylor and Francis Group, LLC.

Description of a new species of the genus Tylopharynx (Nemata : Diplogasteroidea), T-clariamphida sp n., with a redescription of T-foetida (Butschli, 1874) Goffart, 1930

Tylopharynx clariamphida sp. n. is described from muddy sand collected in Anhui Province, China. It can be distinguished from T foetida (Butschli, 1874), the type and only species of the genus, by numerous characters: having 24 to 26 prominent and clearly separated longitudinal ridges, a higher lip region with no hint of a cephalic framework, more prominent amphidial foveae in lateral view, wider and more posteriorly located amphidial apertures, smaller basal knobs of stoma, longer metacorpus, more enlarged phasmids, shorter spicules with shorter digitate terminus, shorter reflexed part of testis, and thicker gubernaculum with more angular shape. For comparison, an expanded description is given for T foetida from Belgium, and SEM photographs of both species are provided.

Long-Wavelength Emission InAs Quantum Dots Grown on InGaAs Metamorphic Buffers

In this work, InAs quantum dots (QDs) grown on a linear graded InGaAs metamorphic buffer layer by molecular beam epitaxy have been investigated. The growth of the metamorphic buffer layers was carefully optimized, yielding a smooth surface with a minimum root mean square of roughness of less than 0.98 nm as measured by atomic force microscopy (AFM). InAs QDs were then grown on the buffer layers, and their emission wavelength at room-temperature is 1.49 mu m as measured by photoluminescence (PL). The effects of post-growth rapid thermal annealing (RTA) on the optical properties of the InAs QDs were investigated. After the RTA, the PL peak of the QDs was blue-shifted and the full width at half maximum decreased.

Lewis酸引发的LLDPE/PS共混体系的原位反应增容及其结构与性能研究

本文以单组分和双组分Lewis酸为催化剂，采用反应加工的方法，制备了原位反应增容的线性低密度聚乙烯/聚苯乙烯共混物（LLDPE/PS），并对原位反应增容的机理、增容体系的结构性能以及Lewis酸对共混组分的降解作用进行了系统研究。 以FTIR和NMR为手段、二甲苯为模拟化合物，确认LLDPE/PS共混体系在Lewis酸为催化剂作用下发生了LLDPE与PS的接枝反应，LLDPE接枝在PS苯环的对位上。形成的原位接枝共聚物对体系起增容作用。 使用溶剂抽提、SEM、DMA、流变和DSC等手段对以单组分Lewis酸AlCl3 为催化剂的LLDPE/PS共混物的结构性能进行了研究。从溶剂抽提前后的重量比计算了接枝物的含量。催化剂用量较低时体系中的接枝物含量随AlCl3的增加而提高，随着AlCl3进一步增加，接枝物含量不会增加反而下降，发现AlCl3导致均聚物的降解。研究结果表明，共混体系中加入适量的AlCl3催化剂后，分散相尺寸减小，分布均匀，储能模量增加，低频区的复数黏度升高。但AlCl3用量过高时使共混物的分散相尺寸增加，分布均匀度下降，储能模量和复数黏度降低。以GPC为手段研究了单组分 Lewis酸AlCl3对共混组分的降解作用，发现对PS的降解作用显著。 由于单组分Lewis酸催化剂会导致共混组分降解，使共混体系的物理机械性能变劣，为此，我们在LLDPE/PS共混物中引入了双组分Lewis酸催化剂（Me3SiCl、InCl3•4H2O）。结果表明双组分Lewis酸催化剂不但能够催化LLDPE和PS的原位接枝反应，获得高性能的LLDPE/PS合金材料，而且不会引发共混组分PS的降解。在催化剂用量固定时，采用双组分催化剂时共混物的拉伸强度随着LLDPE含量的增加几乎保持不变，但冲击强度有十分明显的提高。对比了加入催化剂前后共混物形貌的变化，增容后的共混物中分散相粒子尺寸显著降低，证明了双Lewis酸良好的催化性能。 对以双Lewis酸为催化剂的共混物的流变行为和结晶行为进行了研究。随着催化剂的加入，两相之间的相互作用增强，因此共混物的复数黏度，储能模量和损耗模量都有不同程度的提高。增容后的LLDPE相区变小，因而在冷却过程中出现不同程度的分步结晶现象。 对单组分和双组分Lewis酸催化剂原位反应增容LLDPE/PS共混体系的机理进行了探讨。机理为Friedel-Crafts烷基化反应。在采用单组分Lewis酸催化剂时， AlCl3与体系中含有的微量水等杂质发生反应，形成一个复合物，然后进一步与聚乙烯中的不饱和的双键发生反应形成碳正离子，并攻击LLDPE分子链从而形成大分子的碳正离子LLDPE+，而这些LLDPE+则通过电子的重排而发生剪切断裂。在催化剂的存在下，这些断裂的LLDPE片断取代PS中的苯环上的质子而发生接枝反应，从而形成LLDPE-g-PS共聚物。采用双组分Lewis酸催化剂时，首先发生双Lewis酸的耦合；耦合后的Lewis酸与水等杂质反应生成复合物，然后与非饱和的LLDPE分子反应生成初级碳正离子；初级碳正离子进攻LLDPE主链，生成较大的碳正离子；LLDPE+碳正离子取代PS苯环对位的质子而生成接枝共聚物。

基于ICA和BP网络的电流传感器相位差测量方法

提出了一种高精度在线测定电流传感器相位差的方法.在输入端加入测试信号,在输出端采用独立分量分析(ICA)将该测试信号与传感器正常工作的输出信号分离,通过比较该测试信号输出前后相位的变化确定传感器的相位差.但因ICA算法固有的局限性,同一混合信号每次分离结果误差不同,为了提高分离精度,利用BP网络学习分离结果中相位误差与最大似然指标和负熵的关系,提出了一个指示分离结果误差的评价量,以选取多次分离结果中的最优结果.实验结果证明该评价量的有效性.

基于BP神经网络的系统级电源管理算法

在深入研究目前国际上比较流行的几种系统级电源管理（PM）算法的基础上，利用BP神经网络的非线性映射能力，提出基于BP神经网络的、对任务之间相互间隔时间也就是系统空闲时段的长度进行自适应学习的BPPM算法，具有传统回归PM算法不可比拟的优点。仿真实验表明引入神经网络的电源管理算法较之传统PM算法大大降低了系统级功耗。实现了在不需要建立系统模型、无需预先获得负载统计特性的前提下，通过从系统正常工作产生的数据中不断学习，使系统具有自适应、高效的电源管理能力，以达到降低系统功耗、提高器件可靠性、延长工作寿命的目的。

An improved BP algorithm for pattern recognition

An improved BP algorithm for pattern recognition is proposed in this paper. By a function substitution for error measure, it resolves the inconsistency of BP algorithm for pattern recognition problems, i.e. the quadratic error is not sensitive to whether the training pattern is recognized correctly or not. Trained by this new method, the computer simulation result shows that the convergence speed is increased to treble and performance of the network is better than conventional BP algorithm with momentum and adaptive step size.