几个群体遗传学分析软件的使用

本文对PHYLIP，GENEPOP，FSTAT和BOTTLENECK等几个常用的群体遗传学分析软件的概况及使用．作了简单介绍。     

五种群体遗传学软件的比较

本文对五种群体遗传学数据分析软件FOPGEN32、ARLEQUIN、PHYLIP、MEGA、TREEcON从功能、可处理数据类型、数据输入难度、支持的操作平台、操作简易性、处理结果的直观性以及是否需要辅助软件等进行了比较。得出ARLEQUIN和MEGA使用简单、功能强大，适合群体遗传研究人员使用。     

具有溶磷能力的相思根瘤菌16S rDNA序列分析

为了测定具有溶磷能力的相思根瘤菌的16S rDNA序列。在TY培养基上将菌株培养至对数生长期,以提取的总DNA为模板,采用双向引物进行PCR扩增,对获得的目的产物进行纯化和测序。采用PHYLIP软件中DNADIST程序分析各菌株间的相似性,采用Clustal X和Treeconw软件获得菌株的系统发育树状图。系统发育学分析表明:G7-3、G31-1-5、G31-1-10位于根瘤菌属(Rhizobium)分支中;F7-2-11位于慢生根瘤菌属(Bradyrhizobium)分支;DH001、LH001、LL007酸、Y木1F、3-2-6位于Mesorhizobium分支中;H1-1-1属于类芽孢杆菌(Paenibacillussp.)。该研究初步确定了具有溶磷能力的相思根瘤菌菌株的发育学地位。     

基于18S rDNA序列的涡虫纲三肠目分子系统发育研究

采用18S rRNA对我国常见的4种三肠目涡虫的18S rDNA基因进行序列测定和分析,共获得三肠目2科3属4种的序列,同时结合GenBank中的三肠目18S rDNA序列(22条),以其姐妹群原序列目中的Archimonocelis crucifer为外群,采用MEGA3.0、PHYLIP、PAUP 4.0等分子生物学软件分别构建NJ树、ME树、MP树和ML树,分析三肠目的系统发育关系。结果表明,不同构树方法所得系统树的拓扑结构基本一致。     

新疆泥火山可培养细菌系统发育分析

为了解新疆泥火山可培养细菌的多样性,2009年8月从新疆乌苏泥火山群采集土壤样品,经稀释涂布和划线分离得到31株纯培养菌株,对分离的所有菌株均提取基因组DNA,利用真菌、细菌通用引物扩增得到16S rDNA的序列并测序.将序列在NCBl GenBank数据库中通过Blast软件对其进行同源性检索,使用PHYLIP 3.65软件构建系统发育树.结果表明:31株菌分别归属于13个属,其中15株属于变形菌门(Proteobacteria),12株属于放线菌门(Acti-nobacteria),2株属于厚壁菌门(Firmicutes),2株属于微球菌门(Micrococci).新疆泥火山细菌多样性丰富,优势菌群为盐单胞菌(Halomonas),4号和16号菌株为新种或属.     

棉花黄萎病菌田间动态的分子监测

 分别于1994年3月和1995年3月从同一棉田,采集分离了48个大丽轮枝菌菌株.应用RAPD技术,从240个随机引物中筛选了17个扩增效果好的引物,对供试菌株进行了DNA指纹分析.结果表明:17个引物对48个菌株扩增出120条DNA分子片段,其中43条分子片段为多态带,占35.83%.将扩增结果输入计算机,用PHYLIP分析软件(3.5版本),UPGAME程序进行类聚分析,结果表明95年的5个菌株与其它菌株存在明显的遗传差异.     

新疆泥火山中度嗜盐菌WS1的16S rDNA分析

[目的]了解在新疆泥火山群这一特殊生境条件下一株中度嗜盐菌种属关系。[方法]从新疆泥火山分离得到中度嗜盐菌WS1,测定其生理生化指标,并采用真细菌16SrDNA通用引物PCR扩增WS1菌株的16SrDNA,将得到的片段在NCBI Genbank数据库中通过Blast软件对其进行同源性检索,使用PHYLIP3.65软件构建系统发育树。[结果]该菌能够在浓度0～15%NaCl的条件下生长;PCR扩增得到的片段长度为1 423 bp;同源性比对表明,该菌株与多种涅斯捷连科氏菌的16S rDNA序列同源性高达99%;系统发育树显示WS1菌株与涅斯捷连科氏菌的亲缘关系最近。[结论]结合生理生化指标,初步确定WS1菌株可能是耐盐涅斯捷连科氏菌属的一个亚种。     

GPS在林业工作应用中技术要点及存在问题探讨

该文对GPS手持机的数据采集、GIS Office软件对"任务文件"和"图层文件"的导入导出、View GIS软件对复合图层编辑的操作要点、应用技巧进行了阐述,并针对存在的问题进行了探讨。     

初级配方师软件评述

初级配方师软件是针对中、小型饲料厂配方师或初用配方软件者而设计的。它根据线性规划原理编制而成，是饲料配方计算中最常用、最有效的软件。打开软盘文件，输入饲养标准，通过Excel的“规划求解”功能即可得出理想饲料配方。电脑中应安装完整的Excel，此时“加载宏”下才有“规划求解”选项。本软件的特点是简单易学。打开软盘文件，就可在荧屏上看到一个饲料配方工作表，操作者只要按下列步骤进行，就可顺利算出最低成本配方：1.在列A中调整好计算配方所需的饲料原料。如果需要添加“工作表”上没有列出的饲料原料，可单击“工具”菜…     

鲤斜管虫的分子系统发育研究

测定了鲤斜管虫(Chilodonella cyprini)的ITS1-5.8S-ITS2基因序列,使用PHYLIP3.66软件及MEGA3.1软件构建了其NJ及UPGMA两种分子系统发育树。结果表明:无论采用何种软件,鲤斜管虫都表现出与四膜虫亲缘关系最接近,而与同一属的钩刺斜管虫亲缘关系较远。     

A look from the inside: perspectives on the expansion of food assistance programs at Michigan farmers markets

There has been a recent push to offer more food assistance programs at farmers markets. Yet, as more programs are developed for farmers markets, little input has been sought from those who are ultimately responsible for their implementation. This ethnographic study explores the experiences of farmers markets that have been early adopters of federal food assistance programs. Participant observation and in-depth interviews were used in six early-adopting markets to understand staff perspectives on the challenges and benefits of administering food assistance programs. The results show that even markets with strong organizational capacity experienced significant burdens while operating food assistance programs. In addition, most worried about the sustainability of these programs due to the level of resources needed for their support. The findings suggest that calls to expand food assistance programs to all farmers markets will continue to be met with challenges as many markets will not have the capacity to operate them. Targeting farmers markets with strong organizational capacity may increase the probability of successful implementation, but building the organizational capacity of farmers markets may be necessary for widespread adoption. The study has implications for other sectors of civil society that are increasingly taking on the work of providing government programs.     

实施生态扶贫战略提高生态建设和扶贫工作的整体效果

扶贫开发和生态建设是我国社会发展所面临的两项重要任务。改革开放以来,我国的开放式扶贫工作和生态建设项目取得了举世瞩目的成就。但由于这两项任务实施目标不同,已有项目并没有相互兼顾,近三十年的实践表明,两类项目所瞄准的地区存在较高重叠。因此,实施生态扶贫战略,兼顾减贫和改善生态环境的双重目标,提高两者的整体效果,探索一条符合我国国情的生态建设和扶贫双赢的道路,对于建设社会主义新农村和构建和谐社会具有积极意义。文章最后提出实施生态扶贫战略的四项主要目标。     

不同种植条件的经济施肥决策和计算机应用

本文以田间试验为基础,论述了应用肥料效应函数法进行不同种植制度的施肥决策,主要进展是:1.对不同种植制度的施肥决策问题进行了分类,提出了最大利润、保险收益和最小成本决策目标;2.提出了适于编写计算机程序的多茬作物经济施肥量计算公式,特别是不同作物的加权价格和加权产量的计算公式,克服了轮作和间套作施肥决策在统计上的障碍;3.建立了计算机施肥决策程序,适于不同种植制度,不同施肥条件和多种目标的施肥决策,有助于实现轮作施肥和区域施肥决策的定量化和计算机化。     

我国水稻白叶枯病抗性遗传的评价和利用

 70年代以来我国水稻对白叶枯病抗性遗传的评价和利用取得相当进展，评价了大量包括地方品种、野生稻和国外引进的种质对水稻白叶枯病的抗性，鉴定了许多抗源。其中有些具有基因Xa-3和Xa-4的抗源广泛地用作杂交计划中的供体，选育出一批优良的品种（系），进行了成株抗性和全生育期抗性的评价，同时，广泛地进行了白叶枯病抗性遗传的研究，包括不同抗性类型的品种、亚种间杂交后代和杂交稻育种后代的抗性遗传行为。并就系统研究抗性基因，培育包括1-2个有利基因的改良抗源等方面提出建议。     

Parallel integration of vision modules

Computer algorithms have been developed for several early vision processes, such as edge detection, stereopsis, motion, texture, and color, that give separate cues to the distance from the viewer of three-dimensional surfaces, their shape, and their material properties. Not surprisingly, biological vision systems still greatly outperform computer vision programs. One of the keys to the reliability, flexibility, and robustness of biological vision systems is their ability to integrate several visual cues. A computational technique for integrating different visual cues has now been developed and implemented with encouraging results on a parallel supercomputer.     

Farm to school in British Columbia: mobilizing food literacy for food sovereignty

Farm to school programs have been positioned as interventions that can support goals of the global food sovereignty movement, including strengthening local food production systems, improving food access and food justice for urban populations, and reducing distancing between producers and consumers. However, there has been little assessment of how and to what extent farm to school programs can actually function as a mechanism leading to the achievement of food sovereignty. As implemented in North America, farm to school programs encompass activities not only related to school food procurement, but also to the development of student knowledge and skills under the framework of food literacy. Research on farm to school initiatives has largely been conducted in countries with government-supported national school feeding programs; this study examines farm to school organizing in Canada, where there is no national student nutrition program. Using qualitative fieldwork and document analysis, we investigate the farm to school movement in British Columbia, in a context where civil society concerns related to education and health have been the main vectors of farm to school mobilization. Our analysis suggests that, despite limited institutional infrastructure for school meals, the British Columbia farm to school movement has contributed toward realizing goals of food sovereignty through two main mechanisms: advocacy for institutional procurement of local and sustainable foods and mobilizing food literacy for increased public engagement with issues of social justice and equity in food systems.     

CIMES: A package of programs for determining canopy geometry and solar radiation regimes through hemispherical photographs

CIMES is a multi-purpose, multi-platform, and free package of programs for the determination of solar radiation regimes and canopy structure attributes using hemispherical photographs. These command-line programs, like a toolbox, offer a unique set of features such as: a variety of approaches to invert gap fraction data, correction for slope (solar radiation and LAI), and different procedures to account for foliage clumping, spherical statistics for gap fraction distribution, photosynthetically active radiation (PAR) interception under clear- and overcast sky conditions, and sun-fleck dynamics. We present the general overview of the programs, the solar radiation regime, and the canopy structure estimates as processed by CIMES software. The most important point of CIMES compared to other software would be to have statistics and estimates for each single photosite including all available theoretical and empirical algorithms, so that anyone working on methods rather than application will have more freedom compared to other software. For application, the batch processing does everything.     

基于良基语义的协商机制研究

在当今社会生活中,协商已渗透到人类活动的各个方面,自动协商一直是多Agent领域研究的热点之一.近年来,一些学者采用具有非单调特征的回答集程序表示Agent知识,通过回答集程序的相互更新实现协商.虽然目前已经提出一些基于回答集程序的方法来解决协商问题,但这些研究并没有充分考虑协商最优解和协商过程复杂性之间的平衡问题.寻找基于回答集程序的协商解实际上至少是一个NP-难的搜索问题,而回答集程序的良基语义模型在多项式时间内可以计算得到.因此,本文利用良基语义,结合信念修正的思想对协商过程进行优化,从而提出了一个基于良基语义的双边协商模型.该模型可有效缩短协商过程,实现协商最优解和协商过程复杂性之间的平衡.最后,本文通过实验验证了协商模型的有效性和适用性.     

Thrips: Pests of Concern to China and the United States

Thrips are among the most important agricultural pests globally because of the damage inflicted by their oviposition, feeding, and ability to transmit plant viruses. Because of their invasiveness, a number of pest species are common to both China and the United States and present significant challenges to growers of a wide range of crops in both countries. Among the pest thfips common to both countries are four of the major global thrips pests, Frankliniella occidentalis (Pergande), Scirtothrips dorsalis Hood, Thrips palmi Karny, and Thrips tabaci Lindeman. This review addresses characteristics that enable thrips to be such damaging pests and how biological attributes of thrips create challenges for their management. Despite these challenges, a number of successful management tactics have been developed for various cropping systems. We discuss some of these tactics that have been developed, including the use of cultural controls, biological controls, and judicious use of insecticides that do not disrupt overall pest management programs. The exchange of this type of information will help to facilitate management of pest thrips, especially in regions where species have recently invaded. A prime example is F. occidentalis, the western flower thrips, which is native to the United States, but has recently invaded China. Therefore, management tactics developed in the United States can be adapted to China. Because further success in management of thrips requires a thorough understanding of thrips ecology, we discuss areas of future research and emphasize the importance of collaboration among different countries to enhance our overall understanding of the biology and ecology of thrips and to improve management programs for these widespread pests.     

The political economy of fisheries development in the third world

International agencies have contributed significantly to the promotion of capital-intensive fisheries development programs in many Third World nations. Activities of both bilateral and multilateral development assistance agencies are examined and shown to have certain common features, notably production-oriented programs typified by the introduction of powerful new fishing technologies, and the promotion of fishery exports as a means of increasing foreign exchange earnings. The argument is advanced that these programs have been largely detrimental to the best interests of recipient nations because they have ignored both resource limitations and the distributional consequences of such development. Fisheries development programs in the Third World are seen as being shaped by a convergence of institutional and class interests between national and international agencies. The perspective of political economy is used to examine these interests and explain their relation to policy outcomes. Evidence is presented to show that international agencies have contributed to dualistic patterns of industry growth which have skewed development benefits towards a narrow urban elite. Rural small-scale fishers have been increasingly marginalized as a result of their inability to compete over a limited and, in some cases, depleted resource. Fisheries development and resource management need to be seen as complementary aspects of a single process rather than as separate activities. Central to fisheries management is the question of resource allocation between competing users. Suggestions are offered by which international development agencies can play an important role in encouraging resource use patterns which are both biologically sustainable and socially just.