中国对虾育种方法研究与遗传连锁图谱的构建

本研究以中国对虾为材料，以杂交育种和选择育种为目标，进行了系统的中国对虾杂交育种试验、生长性状遗传参数试验及其分子遗传连锁图谱的构建工作。结果表明以不同地理群体杂交作为基础群体，然后采用系统的选择育种方法可以获得较好的选择效果。构建的遗传连锁图谱为中国对虾分子辅助育种提供一定的基础。这些试验结果为中国对虾合理系统的育种工作提供了理论基础和数据支持。其具体结果如下： 1. 试验对中国对虾黄渤海水域乳山湾群体（WYP）和朝鲜半岛南海群体（WKN）的2个群体及其杂交后代不同月龄生长情况和存活率进行了研究，测量体长（TL）、头胸甲长（CL）、头胸甲宽（CW）、第2、3腹节高（HST）、第2、3腹节宽（WST）、体重（BW）和存活率共7个性状，计算各项指标的杂种优势率，并对各性状进行了方差分析和多重比较。其3月龄生长情况和存活率研究结果表明，存活率在乳山湾群体（WYP♀）× 朝鲜半岛南海群体（WKN♂）杂交后代出现杂种劣势外，其他指标都表现出不同程度的杂种优势(4.37%～23.96% )。除了存活率外，杂交后代生长性状均显著高于亲本，乳山湾群体（WYP♀）×朝鲜半岛南海群体（WKN♂）杂交后代高于朝鲜半岛南海群体（WKN♀）× 乳山湾群体（WYP♂）杂交后代，黄渤海水域乳山湾群体高于朝鲜半岛南海群体后代。为确定测量性状与中国对虾体重的相关程度，建立了用体长(X1)，头胸甲宽(X2)，第2、3腹节宽(X3)，头胸甲长(X4)，第2、3腹节高(X5)估计体重的多元回归方程：Y = －2.056 + 0.03X1 + 0.076X2 + 0.078X3 + 0.033X4 + 0.043X5。 2. 中国对虾黄渤海水域乳山湾群体（WYP）和朝鲜半岛南海群体（WKN）2个群体及其杂交后代在4月龄时期的6个生长指标和存活率的杂种优势范围在0.514%到14.95%之间，WYP♀×WKN♂杂交后代在这7个指标中都高于WKN♀×WYP♂杂交后代。5月龄杂交后代也表现出一定程度的杂种优势，其范围在-9.000%～19.090%之间，但头胸甲长、第2、3腹节处高和存活率3个指标出现杂种劣势。不同杂交组合各个阶段生长发育情况和存活率在杂种优势表现出一定的规律。随着月龄的增加，WKN♀×WYP♂杂交后代杂种优势率有所增加，而WYP♀×WKN♂杂交后代的却有所降低。ANOVA分析结果表明，杂交后代在存活率方面与双亲差异不显著。4月龄的分析结果发现杂交后代在WST和BW这2个指标上存在显著差异。LSD多重比较结果显示，WYP♀×WKN♂杂交后代在BW指标上与亲本存在显著差异，在WST指标方面与其他3个组合的后代差异显著。5月龄的数据分析结果发现，杂交后代除体重存在显著差异外，其他各项指标差异均不显著。LSD多重比较结果发现，WKN♀×WYP♂杂交后代体重与其亲本WKN存在显著差异。 3. 对2个野生群体——朝鲜半岛南海岸群体（WKN）和黄渤海群体（WYP）和3个养殖群体——朝鲜半岛群体的养殖一代（FKN），黄海1号（HH1）和即抗98（JK98）进行杂交试验的研究，结果表明JK98 (♀)  WKN (♂)组合在存活率方面最高，其余的依次为WYP (♀) WKN (♂)，WKN (♀) WYP (♂)，FKN (♀)HH1 (♂) 和 WYP (♀) FKN (♂)。而在体重方面FKN(♀)  HH1(♂)组合最高，其余的依次为WKN (♀) WYP (♂)，WYP (♀) WKN (♂)，WYP (♀)FKN (♂) 和 JK98 (♀)WKN (♂)。在所有生长性状方面，JK98 (♀)  WKN (♂)在5个组合中是最低的。方差检测结果表明，TL、CL、HST、LL和BW这5个指标在不同组合间存在差异，而其他指标不存在差异。多重比较结果发现JK98 (♀)WKN (♂)组合的TL与其他组合间差异极显著，HST指标与WKN (♀) WYP (♂)，FKN(♀)  HH1(♂)和 WYP (♀)  WKN (♂)这3个组合差异显著，BW指标与WKN (♀) WYP (♂) 和 FKN(♀)  HH1(♂)差异显著。 4. 通过人工授精的方法建立了中国对虾21个半同胞家系，测量了中国对虾21个半同胞（46个全同胞）家系的TL、CL、CW、HST、WST、第1腹节长（FL）、第6腹节长（LL）。利用MTDFREML软件得到生长性状遗传力在0.15~0.35之间，属于中度遗传力范围。TL的遗传力为0.34±0.071，CL的为0.30±0.070，CW为0.35±0.077，WST为0.33±0.073，HST为0.33±0.073，FL的最低为0.15±0.044，LL的为0.24±0.059。各个性状间表现出高的正相关，其中CW和TL以及HST的遗传相关最大，FL和WST的遗传相关最小。 通过以上杂交育种和选择育种的研究，认为单纯的依靠杂交育种来改善中国对虾的育种工作可能具有一定的局限性。所以在实际的育种过程中，以中国对虾不同群体的杂交后代作为基础群体，并以此为基础进行系统的选择育种应该具有更大的潜力。 5. 本试验利用中国对虾F2群体和AFLP分子标记技术进行了遗传连锁图谱的构建。利用55对AFLP引物组合对F2家系的110个个体进行了研究，结果检测到532个符合作图策略的AFLP标记。利用卡方检验检测分离位点是否符合孟德尔分离定律。对于符合3：1比例的分离位点利用F2自交模型构建性别平均连锁图谱，对于符合1：1比例的分离位点利用拟测交理论分别构建中国对虾的雌性和雄性遗传连锁图谱。雌性、雄性和性别平均遗传图谱分别有28、35和44个连锁群，图谱实际长度分别为1090、1617和1772.1 cM。中国对虾遗传连锁图谱估计基因组长度为2420 cM，符合与人类基因组相比的对虾类基因组长度。中国对虾雄性遗传连锁图谱比雌性遗传连锁图谱长32.6%，这可能说明中国对虾不同性别存在不同的重组率。通过皮尔逊相关系数检测认为AFLP标记在中国对虾图谱上分布均匀。本文利用AFLP标记构建的中国对虾遗传连锁图谱为中国对虾基因组研究和遗传改良提供一定的基础，同时也应该开发微卫星等共显性标记，为遗传连锁图谱的整合提供条件。

智能机器人系统分层递阶智能控制结构的分析与综合

智能机器人是分层递阶智能控制结构开放的复杂巨系统。本文根据神经科学、人脑智能的三个重要特性,对智能机器人系统分屋递阶智能控制结构、功能和各个层级的基本理论做了简要的论述和分析,采用从定性到定量的综合集成技术,用概率模型表达组织级的推理、规划、决策的不确定性,分配协调级的任务,和执行级的控制作用,用熵作为系统分层递阶各级性能的集成测度,建立智能控制的数学模型。智能机器人系统综合可以以下述数学问题为出发点,即寻求适当的决策与控制序列,随智能递降而精度递增的原则,构成系统的总体熵最小,即可获得最优决策、最优控制和最优设计;用在核电站中自动检修的移动式智能机器人系统求熵最小值改善系统性能有效性的事例做了简要说明,进而提出实现的基本途径和应用前景。

赣中变质岩带变泥砂质岩石地球化学特征及其地质意义

赣中变质岩带主要由变泥砂质岩石和少量斜长角闪岩组成。30个变泥砂质岩石样品分析表明，稀土元素分布模式显示明显富集轻稀土元素及Eu负异常[∑REE=129～296μg／g，δEu=0．51～0．86，(La／Yb)N=3．95～12．91，其小相容元素比值高(Th／Sc=0．57～3．59、La／Sc=1．46～12．4、La／Yb=5．84～19．0、La／Sm=4．69～6．87、Th／U=3．40～6．42)，大离子亲石元素富集，Zr、Hf、Sc、Ti、Y、HREE和Sr含量较低，其原岩应为一套砂泥质岩石，沉积于远离陆地的克拉通大陆架浅海环境；δBa=0．10～0．93，Nd同位素亏损地幔模式年龄tDM=1597～2525Ma，εNd(0)=-9．9～-15．8，其源区物质主体由占元占代富铝富钾的花岗质岩石和(或)碎屑沉积岩构成，经历了较强的化学风化作用。

某金矿氰化物灾害性排放的环境影响预测

某大型金矿废水氰化物对下游城市具有很强的环境敏感性，通过室内试验及实地监测，研究了氰化物在该流域的降解特性、规律及影响因素。运用氰化物在该流域的降解规律及其水文条件，预测了各种灾害性排放氰化物对下游流域的环境影响程度，并提出了相应的防治措施。

Proceedings of the Second PHANToM User's Group Workshop

On October 19-22, 1997 the Second PHANToM Users Group Workshop was held at the MIT Endicott House in Dedham, Massachusetts. Designed as a forum for sharing results and insights, the workshop was attended by more than 60 participants from 7 countries. These proceedings report on workshop presentations in diverse areas including rigid and compliant rendering, tool kits, development environments, techniques for scientific data visualization, multi-modal issues and a programming tutorial.

Age-dependence of urinary normal and modified nucleosides in childhood as determined by reversed-phase high-performance liquid chromatography

Modified nucleosides have been characterized as tumor markers for a number of malignant diseases. In order to use these markers in children, the age-dependence of the nucleoside levels in healthy children has to be established and taken into account in diagnostic decisions. In this study, the levels of 12 normal and modified nucleosides in urine of 166 healthy children and adolescents with an age between 1 day and 19 years are determined by reversed-phase HPLC, and age-dependent reference ranges are defined. The urinary nucleoside concentrations are related to the creatinine concentrations, which allows the use of randomly collected urine samples. All nucleoside levels in urine of children decrease with age, most pronounced during the first 4 years of life, and the age-dependence of the reference values of the individual nucleosides can be approximated by a mathematical function y = b(0) + b(1) (1/x) with the regression coefficients b(0) and b(1), the nucleoside levels y and the age x between 1 year and 19 years. In the very young children, the shifts in the nucleoside concentrations are more differentiated. Starting with low levels on the first day of life, the concentrations of all studied nucleosides rise up to an age of 1-2 months, when they reach their absolute maximum for all age periods, and then decrease. (C) 2004 Elsevier B.V. All rights reserved.

Analysis of the elements of catabolite repression in Clostridium acetobutylicum.

The ptsH gene, encoding the phosphotransferase protein HPr, from Clostridium acetobutylicum ATCC 824 was identified from the genome sequence, cloned and shown to complement a ptsH mutant of Escherichia coli. The deduced protein sequence shares significant homology with HPr proteins from other low-GC gram-positive bacteria, although the highly conserved sequence surrounding the Ser-46 phosphorylation site is not well preserved in the clostridial protein. Nevertheless, the HPr was phosphorylated in an ATP-dependent manner in cell-free extracts of C. acetobutylicum. Furthermore, purified His-tagged HPr from Bacillus subtilis was also a substrate for the clostridial HPr kinase/phosphorylase. This phosphorylation reaction is a key step in the mechanism of carbon catabolite repression proposed to operate in B. subtilis and other low-GC gram-positive bacteria. Putative genes encoding the HPr kinase/phosphorylase and the other element of this model, namely the catabolite control protein CcpA, were identified from the C. acetobutylicum genome sequence, suggesting that a similar mechanism of carbon catabolite repression may operate in this industrially important organism.

Exploring the relationship between impulsivity and decision-making on mobile devices.

Mobile devices offer a common platform for both leisure and work-related tasks but this has resulted in a blurred boundary between home and work. In this paper we explore the security implications of this blurred boundary, both for the worker and the employer. Mobile workers may not always make optimum security-related choices when ‘on the go’ and more impulsive individuals may be particularly affected as they are considered more vulnerable to distraction. In this study we used a task scenario, in which 104 users were asked to choose a wireless network when responding to work demands while out of the office. Eye-tracking data was obtained from a subsample of 40 of these participants in order to explore the effects of impulsivity on attention. Our results suggest that impulsive people are more frequent users of public devices and networks in their day-to-day interactions and are more likely to access their social networks on a regular basis. However they are also likely to make risky decisions when working on-the-go, processing fewer features before making those decisions. These results suggest that those with high impulsivity may make more use of the mobile Internet options for both work and private purposes but they also show attentional behavior patterns that suggest they make less considered security-sensitive decisions. The findings are discussed in terms of designs that might support enhanced deliberation, both in the moment and also in relation to longer term behaviors that would contribute to a better work-life balance.

The rpf gene of Micrococcus luteus encodes an essential secreted growth factor

Galina V. Mukamolova, Obolbek A. Turapov, Konstantin Kazarian, Miroslav Telkov, Arseny S. Kaprelyants, Douglas B. Kell and Michael Young (2002). The rpf gene of Micrococcus luteus encodes an essential secreted growth factor. Molecular Microbiology, 46 (3), 611-621. Sponsorship: BBSRC / Russian Foundation for Basic Research (grant 00-04-48691)/ WHO Global Programme for Vaccines and Immunization / Wellcome Trust RAE2008

Coronica general de la Orden de San Benito, Patriarca de Religiosos

Colofón en v.1, v.2, v.5, v.6, y v.7.

To Queue or Not to Queue: When Queueing is Better Than Timesharing in a Distributed System

We examine the question of whether to employ the first-come-first-served (FCFS) discipline or the processor-sharing (PS) discipline at the hosts in a distributed server system. We are interested in the case in which service times are drawn from a heavy-tailed distribution, and so have very high variability. Traditional wisdom when task sizes are highly variable would prefer the PS discipline, because it allows small tasks to avoid being delayed behind large tasks in a queue. However, we show that system performance can actually be significantly better under FCFS queueing, if each task is assigned to a host based on the task's size. By task assignment, we mean an algorithm that inspects incoming tasks and assigns them to hosts for service. The particular task assignment policy we propose is called SITA-E: Size Interval Task Assignment with Equal Load. Surprisingly, under SITA-E, FCFS queueing typically outperforms the PS discipline by a factor of about two, as measured by mean waiting time and mean slowdown (waiting time of task divided by its service time). We compare the FCFS/SITA-E policy to the processor-sharing case analytically; in addition we compare it to a number of other policies in simulation. We show that the benefits of SITA-E are present even in small-scale distributed systems (four or more hosts). Furthermore, SITA-E is a static policy that does not incorporate feedback knowledge of the state of the hosts, which allows for a simple and scalable implementation.

Multi-Scale 3D Scene Flow from Binocular Stereo Sequences

Scene flow methods estimate the three-dimensional motion field for points in the world, using multi-camera video data. Such methods combine multi-view reconstruction with motion estimation. This paper describes an alternative formulation for dense scene flow estimation that provides reliable results using only two cameras by fusing stereo and optical flow estimation into a single coherent framework. Internally, the proposed algorithm generates probability distributions for optical flow and disparity. Taking into account the uncertainty in the intermediate stages allows for more reliable estimation of the 3D scene flow than previous methods allow. To handle the aperture problems inherent in the estimation of optical flow and disparity, a multi-scale method along with a novel region-based technique is used within a regularized solution. This combined approach both preserves discontinuities and prevents over-regularization – two problems commonly associated with the basic multi-scale approaches. Experiments with synthetic and real test data demonstrate the strength of the proposed approach.