倒刺鲃属鱼类的系统发育及其动物地理学研究(英文)

倒刺鲃属（Spinibarbus）鱼类隶属于鲤科的鲃亚科,共有5个有效种。应用分支系统学原理和方法,对该属鱼类的系统发育和地理分化进行了研究。在进行性状分析时,以四须鲃属（Barbodes）作为倒刺鲃属的外类群,理由是它们的系统发育关系较近,而且四须鲃属较原始。分析结果表明,倒刺鲃属鱼类共有3个共同离征,表明该属鱼类为一个单源群。在19个外部形态和内部骨骼特征的基础上,构建了倒刺鲃属鱼类的系统发育分支图。姐妹群A（S.hollandi）和 B-E（S.sinensis+S.denticulatus+S.yunnanensis+S.polyepis）代表了倒刺鲃属内的第一次谱系分化。第二次谱系分化发生于姐妹群B（S.sinensis）和C-E（S.dentlculalus+S.yunnanensis+S.polylepis）之间;姐妹群B分布于长江水系,而姐妹群C-E则分布于珠江水系以南,包括海南岛;基于谱系分化和姐妹群的地理分布,推测此次谱系分化可能是由于云贵高原的抬升及同时发生的水系分流所致。第三次谱系分化则发生于姐妹群C（S.denticulalus）和D-E（S.yunnanensis+S.polyle...

On-going generation of multiple forms of HIV-1 intersubtype recombinants in the Yunnan Province of China

Objectives: To investigate the molecular epidemiology of HIV in China's Yunnan Province, where the initial HIV-1 outbreak among injecting drug users (IDU) occurred in 1989, and to analyse the genesis and interrelationship of the epidemic with that in surrounding areas. Design: A molecular epidemiological investigation was conducted among IDU in three prefectures in Yunnan Province, including Wenshan (east), Honghe (southeast) and Dehong (west). Methods: Thirty-nine specimens were collected from consenting IDU in 2000-2001. The nucleotide sequences of 2.6 kb gag-RT and 340 base pair (bp) env (C2/V3) regions were determined. Phylogenetic tree and recombination breakpoint analyses were performed. Results: The circulating recombinant form (CRF), CRF08_BC, predominated in east Yunnan near Guangxi Province (89% in Wenshan and 81% in Honghe), whereas it was not detected in Dehong(0/14) in the west. In contrast, 71% (10/14) of the Dehong isolates were unique recombinant forms (URF), mostly between subtypes B' (Thailand variant of subtype B) and C, with distinct profiles of recombination breakpoints. The subtype B' accounts for the remaining 29% (4/14) of Dehong isolates. Interestingly, two Honghe isolates (2/16) shared some of the precise B'/C recombination breakpoints with CRF07_BC. Conclusion: New recombinant strains are arising continually in west Yunnan near the Myanmar border. Some appeared to be secondary recombinants derived from CRF07_BC that had further recombined with other strains. The uneven distribution of subtypes, CRF and URF, suggests the presence of independent transmission networks and clusters among IDU in Yunnan. (C) 2002 Lippincott Williams Wilkins.

The efficiency of compensation grouting in sands

Physical model experiments on compensation grouting in sands were performed in two different setups (Cambridge and Delft). The effect of water-cement (w/c) ratio, bentonite content (b.c.) and injection rate on compensation efficiency was investigated. Results show a considerable drop in compensation efficiency resulted from reducing the soil density. Injection in dense sand (R.D. = 93%) resulted in efficiencies between 40-90%, whereas injection in medium-dense sand (R.D. = 60-75%) yielded in reduced efficiencies between 10-40%. When the w/c ratio increased from 0.5 to 1.5 for a given density (R.D. = 93%) and the b.c. of 4%, the compensation efficiency value decreased. Typical efficiencies were between 60% and 40-50% for w/c ratios of 0.5 and 1.5, respectively. The values of compensation and grout efficiencies were almost equal, suggesting that pressure filtration happens mainly during injection. Increasing the b.c. improved the compensation efficiency. When a higher b.c. of 12% to 14% was used, typical compensation efficiencies in dense sand were 78 and 90% for w/c ratios of 1.5 and 1.8 respectively. © 2012 Taylor & Francis Group.

三峡库区浮游生物群落DNA结构与水体理化因子的分析

本文对三峡水库大坝至香溪河段所设A、B、C、D、E、F和G等7个站点浮游生物群落DNA进行了RAPD分子生物学研究,并分析了其与水体理化因子的关系。各站点间RAPD研究表明:D和E首先聚到一组,然后与A聚到一起,最后与C聚成一大类;B和F聚成一大类;站点G独自归于一类。而理化因子聚类结果显示:B首先与C聚为一小类,再与D聚到一起,然后与G、F聚成的小类聚为一类,而E与A分别单独归为一类。比较发现,RAPD聚类结果中相距较近的站点在理化因子聚类中显示为相距较远的站点(如站点A、C、D、E之间),而在RAPD

三峡库区浮游生物群落结构与DNA多态性比较分析

以三峡库区所设A、B、C、D、E、F和G等7个站点为研究区域,利用RAPD技术就其浮游生物群落遗传多样性与物种多样性的关系进行了探索性研究．共鉴定出浮游生物41种,其中藻类4种,原生动物10种,轮虫类19种,枝角类4种,桡足类4种．物种组成相似性最高的是B站和C站,最低的是A站和F站．而站点间浮游生物群落遗传距离分析表明:相距最近的是C站与D站,最远的为D站与F站．树状聚类图也显示:各站点物种组成聚为一类;而DNA多态性RAPD最先聚在一起的是B与F,它们的对应枝由A、C、D、E构成,G单独成为一枝．研究

菜籽粕对异育银鲫免疫应答能力的影响

试验鱼以投喂饲料的不同和是否注射抗原共分为10组,即免疫组:A、B、C、D、E组,免疫对照组:a、b、c、de、组,饲料对照组:A、a组。饲料试验组B、C、D、E、bc、、d、e组。其中,饲料对照组以豆粕和鱼粉为基础蛋白源,饲料试验组分别以双低菜籽粕和普通菜籽粕等氮替代对照组中50%(B、b;D、d)和100%(C、c;E、e)的豆粕蛋白,测定异育银鲫血液白细胞和头肾吞噬细胞的吞噬活性、血清溶菌酶活性、血清补体(C3,C4)含量、血清凝集抗体效价及免疫保护率。结果表明:从免疫后21 d开始,饲料试验组E、

青海湖及其相邻水系特有裸鲤属鱼类的分子系统发育

对来自青海湖、黄河和柴达木水系特有的青海湖裸鲤、花斑裸鲤和斜口裸鲤149个个体的Cytb基因全序列进行了测定和分析.一致的系统进化树显示,以上3个物种并未形成3个独立的单系群;而是分为3个谱系:谱系A包括青海湖裸鲤、斜口裸鲤和黄河花斑裸鲤的一部分;谱系B由黄河花斑裸鲤的另一部分组成;谱系C则由来自柴达木盆地格尔木河的花斑裸鲤形成单系群.AMOVA分析显示,大部分的遗传变异来自于谱系间(93.12%),提出该地区裸鲤属鱼类存在3个多样化谱系.青海湖裸鲤与其甘子河亚种在Cytb水平没有形成分化,不支持青海湖裸

Confidence in beliefs about pain predicts expectancy effects on pain perception and anticipatory processing in right anterior insula.

Psychological factors play a major role in exacerbating chronic pain. Effective self-management of pain is often hindered by inaccurate beliefs about the nature of pain which lead to a high degree of emotional reactivity. Probabilistic models of perception state that greater confidence (certainty) in beliefs increases their influence on perception and behavior. In this study, we treat confidence as a metacognitive process dissociable from the content of belief. We hypothesized that confidence is associated with anticipatory activation of areas of the pain matrix involved with top-down modulation of pain. Healthy volunteers rated their beliefs about the emotional distress that experimental pain would cause, and separately rated their level of confidence in this belief. Confidence predicted the influence of anticipation cues on experienced pain. We measured brain activity during anticipation of pain using high-density EEG and used electromagnetic tomography to determine neural substrates of this effect. Confidence correlated with activity in right anterior insula, posterior midcingulate and inferior parietal cortices during the anticipation of pain. Activity in the right anterior insula predicted a greater influence of anticipation cues on pain perception, whereas activity in right inferior parietal cortex predicted a decreased influence of anticipatory cues. The results support probabilistic models of pain perception and suggest that confidence in beliefs is an important determinant of expectancy effects on pain perception.

Modulation of pain ratings by expectation and uncertainty: Behavioral characteristics and anticipatory neural correlates.

Expectations about the magnitude of impending pain exert a substantial effect on subsequent perception. However, the neural mechanisms that underlie the predictive processes that modulate pain are poorly understood. In a combined behavioral and high-density electrophysiological study we measured anticipatory neural responses to heat stimuli to determine how predictions of pain intensity, and certainty about those predictions, modulate brain activity and subjective pain ratings. Prior to receiving randomized laser heat stimuli at different intensities (low, medium or high) subjects (n=15) viewed cues that either accurately informed them of forthcoming intensity (certain expectation) or not (uncertain expectation). Pain ratings were biased towards prior expectations of either high or low intensity. Anticipatory neural responses increased with expectations of painful vs. non-painful heat intensity, suggesting the presence of neural responses that represent predicted heat stimulus intensity. These anticipatory responses also correlated with the amplitude of the Laser-Evoked Potential (LEP) response to painful stimuli when the intensity was predictable. Source analysis (LORETA) revealed that uncertainty about expected heat intensity involves an anticipatory cortical network commonly associated with attention (left dorsolateral prefrontal, posterior cingulate and bilateral inferior parietal cortices). Relative certainty, however, involves cortical areas previously associated with semantic and prospective memory (left inferior frontal and inferior temporal cortex, and right anterior prefrontal cortex). This suggests that biasing of pain reports and LEPs by expectation involves temporally precise activity in specific cortical networks.

几种罗非鱼乳酸脱氢酶和苹果酸脱氢酶同工酶的电泳研究

用淀粉凝胶垂直平板电泳比较分析了三种口孵类型罗非鱼的6种组织的乳酸脱氢酶(LDH)和苹果酸脱氢酶(MDH)同工酶谱及其相对迁移特性,发现这两种同工酶在各个种内表现出组织的分布特异性,而在各个种间又具有明显的差异。利用LDH同工酶的F基因和MDH同工酶的A、B、C、D基因作为遗传标志,能够将亲缘关系相近的这三种罗非鱼区别开来,从而为形态分类学提供了新的生化证据,并且对于以育种为目的的亲本选择,具有一定的实用意义。

Properties of exchange interaction in Yb3Fe5O12 under extreme conditions

In Yb3Fe5O12, the exchange effective field can be expressed as H-eff = -lambda center dot center dot center dot M-Fe = -lambda chi(eff)center dot center dot center dot H-e = -gamma center dot center dot center dot H-e where gamma is named as the exchange field parameter and H-e is the external magnetic field. Then, in this paper, by the discussions on the characteristics of the exchange field parameter gamma, the properties of exchange interaction in ytterbium iron garnet (Yb3Fe5O12) are analyzed under extreme conditions (high magnetic fields and low temperatures). Our theory suggests that the exchange field parameter gamma is the function of the temperatures under different external magnetic fields, and gamma = a+b center dot center dot center dot T+c center dot center dot center dot T-2, where the coefficients a, b, c are associated with the external magnetic fields and the magnetized directions. Thus, the temperature-dependence, field-dependence and anisotropic characteristics of the exchange interaction in Yb3Fe5O12 are revealed. Also, excellent fits to the available experiments are obtained. (C) 2009 Elsevier B.V. All rights reserved.

Thermal entanglement in a two-qubit Heisenberg XXZ spin chain under an inhomogeneous magnetic field

The thermal entanglement in a two-qubit Heisenberg XXZ spin chain is investigated under an inhomogeneous magnetic field b. We show that the ground-state entanglement is independent of the interaction of z-component J(z). The thermal entanglement at the fixed temperature can be enhanced when J(z) increases. We strictly show that for any temperature T and J(z), the entanglement is symmetric with respect to zero inhomogeneous magnetic field, and the critical inhomogeneous magnetic field b(c) is independent of J(z). The critical magnetic field B-c increases with the increasing parallel to b parallel to but the maximum entanglement value that the system can arrive at becomes smaller.

A 16-term error model based on linear equations of voltage and current variables

Formulation of a 16-term error model, based on the four-port ABCD-matrix and voltage and current variables, is outlined. Matrices A, B, C, and D are each 2 x 2 submatrices of the complete 4 x 4 error matrix. The corresponding equations are linear in terms of the error parameters, which simplifies the calibration process. The parallelism with the network analyzer calibration procedures and the requirement of five two-port calibration measurements are stressed. Principles for robust choice of equations are presented. While the formulation is suitable for any network analyzer measurement, it is expected to be a useful alternative for the nonlinear y-parameter approach used in intrinsic semiconductor electrical and noise parameter measurements and parasitics' deembedding.

The effects of nonlinear couplings and external magnetic field on the thermal entanglement in a two-spin-qutrit system

We investigate the effects of nonlinear couplings and external magnetic field on the thermal entanglement in a two-spin-qutrit system by applying the concept of negativity. It is found that the nonlinear couplings favor the thermal entanglement creating. Only when the nonlinear couplings vertical bar K vertical bar are larger than a certain critical value does the entanglement exist. The dependence of the thermal entanglement in this system on the magnetic field and temperature is also presented. The critical magnetic field increases with the increasing nonlinear couplings constant vertical bar K vertical bar. And for a fixed nonlinear couplings constant, the critical temperature is independent of the magnetic field B. (c) 2005 Elsevier B.V. All rights reserved.