Analysis of simple sequence repeats markers derived from Phytophthora sojae expressed sequence tags

Five thousand and eight hundred publicly available expressed sequence tags (ESTs) of Phytophthora sojae were electronically searched and 415 simple sequence repeats (SSRs) were identified in 369 ESTs. The average density of SSRs was one SSR per 8.9 kb of EST sequence screened. The most frequent repeats were trinucleotide repeats (50.1%) and the least frequent were tetranucleotide repeats (8.2%). Forty primer pairs were designed and tested on 5 strains of P. sojae. Thirty-three primer pairs had successful PCR amplifications. Of the 33 functional primer pairs, 28 primer pairs produced characteristic SSR bands of the expected size, and 15 primer pairs (45.5%) detected polymorphism among 5 tested strains of P. sojae. Based on the polymorphisms detected with 20 EST-SSR markers, the 5 tested strains of P. sojae were clustered into 3 groups. In this study, the SSR markers of P. sojae were developed for the first time. These markers could be useful for identification, genetic variation study, and molecular mapping of P. sojae and its relative species.     

STS的首次国际峰会:社会中的科学技术京都论坛

2004年11月14—16日，在日本国立京都国际会馆举行了首届STS论坛。这是一次跨国界、跨界别的高峰会议，有50个国家和地区的部长级官员、科学界领袖、高技术公司的企业家、政策制订者共约480位代表出席论坛，以非正式的方式进行对话。日本现任首相小泉纯一郎说，这是“世界上处理人类在对付科学和技术的明面和暗面时所面临的问题以及人类未来的问题的第一个尝试”，     

多媒体教学中学生英语听力心理分析与听力能力的形成

听力理解是一个复杂的心理语言过程和创造的思维过程。训练听力是英语教学的目标之一，听力教学培养学生理解和应答口头语言的能力，目前已普遍受到重视。本文试图通过剖析多媒体教学中影响学生听力提高的心理因素，探索改进和完善听力的教学方法，使听力教学从以应试为目的变为一种求知的途径。     

完善个人所得税制的探讨

本文论述了我国在完善个所得税制进程中,要以优化税制为基础,通过降低税率,减少档次,拓宽税基,强化征管,增加收入,逐步实现公正、中性、简化和具有国际竞争力的个人所得税税制改革目标。     

Swelling Studies of Chitosan-Gelatin Films Cross-Linked by Sulfate

0　IntroductionChitosanisadeacetylatedderivativeofchitin ,containinginitsstructure glucosamineandacetylglucosamine joinedthroughβ (1→ 4 )linkages.ItisinsolubleinwaterandcommonorganicsolventsbutsolubleatapHunder 6 .5acidicmedia.Duetoitsexcellentbiodegradableandbiocompatiblecharacter,chi tosanhasbeenexaminedextensivelyinthepharmaceuticalindus tryforitspotentialinthedevelopmentofdrugdeliverysys tems[1 ,2 ] .Gelatinisabiodegradablepolymerofwidesafety ,pro ducedfromcollagen ,themostabundantprote…     

Numerical tests of efficiency of the retrospective time integration scheme in the self-memory model

A set of numerical tests was carried out to compare the retrospective time integral scheme in a self-memory model,whose dynamic kernel is the barotropical quasi-geostrophic model, with the ordinary centered difference scheme in the barotropical quasigeostrophic model. The Rossby-Haurwitz wave function was taken as the initial fields for both schemes. The results show that in comparison with the ordinary centered difference scheme, the retrospective time integral scheme reduces by 2 orders of magnitude the forecast error, and the forecast error increases very little with lengthening of the time-step. Therefore, the retrospective time integral scheme has advantages of improving the forecast accuracy, extending the predictable duration and reducing the computation amount.     

Study and Application of Internal Coating Technique to Drag Reduction of the Trunk Pipeline for the West-East Gas Pipeline

Coverage layer coated in the internal wall of pipeline enables the friction drag to be reduced, the throughput and the gas transmission efficiency to be increased, the frequency of pigging and the number of the intermediate compressor station to be reduced, and the power consumption of the compressor to be decreased etc. The drag reduction is a high advanced scientific technique with outstanding economical benefit. The study and application of internal coating technique for drag reduction of 4000km trunk pipeline in West-East gas transmission pipeline (WEGTP) project are described, in which the main points are the drag reduction principle, coating process and the indoor study of this technique with own-decided knowledge property right at home.     

Adaptive Event-Based Consensus of Multi-Agent Systems with General Linear Dynamics

In this paper, adaptive event-based consensus of multi-agent systems with general linear dynamics is considered. A novel adaptive event-based controller and a state-dependent triggering function are proposed for each agent. The consensus can be achieved without the assumption that (A,B) is stabilizable. Furthermore, the Zeno-behavior of the concerned closed-loop system is also excluded under certain conditions. Finally, a numerical simulation example is presented to show the effectiveness of the theoretical results.     

Seasonal Variation and Land-Use/Land-Cover Type Impacts on the Correlation of Urban Heat Island Intensity and Difference Vegetation Index with Satellite Data in Xi’an,China

Green coverage has pronounced influences on urban heat island (UHI) effect, while the impacts of seasonal variation and Land-Use/Land-Cover (LULC) types on this effect has not been implemented. This paper investigated the spatio-seasonal characteristics of urban thermal environment and the vegetation-soil mixed area, and then explored the effects of vegetation status on UHI intensity from the perspectives of seasons and regions in Xi’an using four Landsat 8 images. UHI intensity index was implemented to extract UHI intensity based on thermal infrared imagery, and difference vegetation index (DVI) was used to represent vegetation-soil mixed area. Results indicated that DVI has impacts on UHI intensity, and their relations vary with season and region. In the whole Xi’an, if UHI intensity is smaller than -0.1, DVI increases with the increase of UHI intensity; whereas for UHI intensity is greater than -0.1, DVI decreases with increases of the UHI intensity from early spring to autumn. The highest correlation level was discovered in the autumn map (R²=0.713). Results of correlation analysis further displayed that DVI positively correlated with UHI intensity at impervious surface, and that the main urban area possessed the best correlation with R²=0.564 5.