Parameters affecting the frequencies of transformation and co-transformation with synthetic oligonucleotides in yeast.

Factors influencing the direct transformation of the yeast Saccharomyces cerevisiae with synthetic oligonucleotides were investigated by selecting for cyc1 transformants that contained at least partially functional iso-1-cytochrome c. Approximately 3 x 10(4) transformants, constituting 0.1% of the cells, were obtained by using 1 mg of oligonucleotide in the reaction mixture. Carrier, such as heterogeneous oligonucleotides, enhanced transformation frequencies. Transformation frequencies were dramatically reduced if the oligonucleotides had a large number of mismatches or had terminally located mismatches. Transformation with oligonucleotides, but not with linearized double-strand plasmid, was efficient in a rad52- strain, suggesting that the pathway for transformation with oligonucleotides is different from that with linearized double-strand plasmid. We describe a procedure of co-transformation with two oligonucleotides, one correcting the cyc1 defect of the target allele in the host strain, and the other producing a desired amino acid alteration elsewhere in the iso-1-cytochrome c molecule; approximately 20% of the transformants obtained by co-transformation contained these desired second alterations.     

Genome-wide genetic diversity may help identify fine-scale genetic structure among lake whitefish spawning groups in Lake Erie

In Lake Erie, lake whitefish Coregonus clupeaformis supported lucrative fisheries before populations were decimated by overfishing and water quality degradation. In recent years, there has been a renewed interest in lake whitefish and management of the fishery they support. Lake whitefish spawn on several reefs throughout Lake Erie, but the relative recruitment dynamics and contributions of spawning groups to the fishery are not well understood. Modern high-throughput sequencing approaches offer new opportunities to census population diversity and to identify subtle differences among closely related populations. We used high-throughput sequencing data to evaluate the genetic structure and diversity of lake whitefish collected opportunistically across broad spatial scales in Lake Erie. Using RAD-capture (Rapture), we sequenced and genotyped individuals (N = 88) from the west, central, and east basin of Lake Erie at 120,268 single nucleotide polymorphisms (SNPs). Lake whitefish from Niagara and Crib Reefs (west basin) diverged from the three collections. Interestingly, these were the only lake whitefish collected during the act of spawning (late November), and all other fish were collected pre-spawn (August-early November). These results suggest that some lake whitefish spawning reefs may be reproductively isolated, though definition of these groups into stocks will require more intentional sampling during the act of spawning.     

基于GIS的土地信息系统的设计与实现

土地信息系统是面向土地管理的地理信息系统,是由土地相关信息组成的数据库以及收集、描述、处理和分配这些数据的技术方法组成.文中介绍了一个土地信息系统的组成,并着重讨论了系统的技术要点及实现方法.     

面向机器人装配设计与规划的集成框架

本文针对面向机器人装配的产品设计与装配规划中的关键问题,分析实际产品设计与 装配规划的一般过程,提出了将面向机器人装配的产品设计与装配规划进行系统集成的框架 ,并对系统的各个模块的功能和实现作了研究探讨,通过在工程实践中的应用验证了其正确 性和有效性．     

基于组件技术开发的重要实现途径——RAD的思考

RAD思想就是可视化的CBD开发,通过封装好的标准事件,来和系统进行交互;通过改写事件处理程序,完成用户要求的处理。RAD的作用首先是将程序员从抽象的用户界面的设计中解放出来,把更多的精力和时间投入到真正需完成的逻辑代码的编写中去。介绍了实际秉承了CBD优势,又可可视化进行的高效开发方式——RAD。     

The utility of rapid application development in large-scale, complex projects

This paper describes an investigation into the utility of an agile development approach known as rapid application development (RAD) within a large-scale development project conducted within the public sector in the UK. Features of RAD as an 'agile' information systems development method (ISDM) are discussed and previous research identifying properties of development environments most conducive to its application are described. A case study is then presented based upon a long-term qualitative investigation of the 'unbundling' of a commercial RAD-like ISDM. The evidence from this case leads us to question established wisdom in relation to appropriate adoption and application of agile development within large-scale and complex development environments.     

A GIS based component-oriented integrated system for estimation, visualization and analysis of road traffic air pollution

Road traffic is a dominant source of air pollution. Therefore it is necessary to provide decision-makers with up-to-date emission information in an easily understandable form. To achieve this goal we have integrated existing emission calculation software with a graphical user interface, which includes a GIS (geographical information system) component. The paper first gives a summary of the basic road traffic emission model and then focuses on the design and implementation of the computer application with the emphasis on the used component and GIS technology. The integrated emission evaluation system offers entirely new ways of using the emission model and gives additional visualization and analysis possibilities.     

1027和RAD7型测氡仪测氡效果的研究与评价

采用1027型和RAD7型连续测氡仪对比测量某房间的氡气含量。结果发现,对于同一房间,1027型连续测氡仪不论采用哪种工作状态(enable和disable),测量数据和RAD7型连续测氡仪测量数据差别都很大;1027型测氡仪测量数据稳定性差,波动较大,RAD7型连续测氡仪测量数据稳定性好,波动较小;湿度对2种仪器的影响都很大。