生物材料与生物传感器

论述了具有分子识别功能的生物材料的开发应用现状,生物材料的元件化,生物元件的改良,生物传感器的原理及电极式、热敏式、光敏式、声波检测器式生物传感器的研究开发动向,最新成果及未来展望.     

不同培肥管理措施对土壤微生物生态特征的影响

本文研究了厩肥区、秸杆区、化肥区和无肥对照区四种不同培肥管理措施对土壤微生物生态特征的影响,结果表明,施入厩肥、化肥或秸杆还田均能明显增加土壤微生物生物量及呼吸量;土壤微生物生物质量、土壤呼吸及代谢商等微生物指标均与土壤有机质的变化呈相同的变化趋势;BIOLOG生态盘测试亦揭示了培肥管理措施能明显影响土壤微生物的群落结构。     

Understanding and analysing activity and learning in virtual communities

Abstract  The purpose of this study is to provide a preliminary framework to observe, analyse and evaluate both activity and learning in virtual communities. So various types of virtual communities will be studied by examining their relationship to socialisation and learning. After a presentation of the main ideas of Wenger's social learning theory, the principal components of the social context of the emergence and evolution of virtual communities will be described. It will show how taking this context into account enables the definition of four principal types of virtual communities: community of interest, goal-oriented community of interest, learners' community and community of practice and describe how the activity of these communities develops according to the goals they set for themselves and to the strategies they adopt to reach them. For each type of virtual community, an attempt will be made to determine the process of negotiation of meaning at the base of learning, and to describe the learning performed in terms of participation and reification processes.     

微生物腐蚀机制及检测方法

生物膜在自然界无处不在,但生物膜造成的腐蚀却基本上被忽略。综述了微生物尤其是硫酸盐还原菌的腐蚀机理,并对微生物腐蚀研究方法做了简单介绍,以期对火电厂微生物腐蚀的研究工作有一定的帮助。     

Design issues of a distance learning course on Business on the Internet

Abstract The paper presents the main design issues of a distance learning course on Business on the Internet. The instructional design is based on a learner-centred instructional strategy which allows learners to construct their own knowledge while solving real business problems and transferring their knowledge to other learners. They learn autonomously taking the responsibility for their learning and following their individual cognitive styles, interests, preferences. The learners have access to the Internet being members of a global, cooperative learning community. The learning community involves students and tutors who collectively take responsibility for the design and evaluation of the course content and the teaching methods to be applied. Both students and tutors inhabit a virtual learning environment that offers different virtual places and services: virtual university, virtual enterprise, auditoriums, workshop rooms, cafes, libraries, etc. where students from different locations can meet, interact, learn and work together, as if they were face-to-face.     

厘清关系确保大学城健康发展

我国高等教育的跨跃式发展，催生了大学城。大学城既是社会现象，又是一种全新的大学组织制度。文章认为要确保大学城健康发展，必须厘清大学城中大学与大学、大学与企业、大学与社区、大学与政府等诸方面的关系。     

Effect of Exogenous Rare Earths on Microbial Characteristics in Paddy Soil

Duetoincreasingcropyieldsandimprovingcropquality ,REammoniumhydrogencarbonatecomplexfertilizerwereappliedwidelyinsoils ,whichacceler atetheaccumulationofREinsoilsafteragriculturalapplication[1,2 ] .Previousstudieshavereportedaccu mulationofREsinsoilissignificantafter 3monthsofagriculturalapplication[3] ,andREhardlymigratedownward[4 ] .Itiscertaintythatagriculturalapplica tionofREcanresultREaccumulationinsoilandmayhaveaneffectonsoilmicrobialactivities .Soilmicro bialbiomassisamarkerofthemi…     

Crossing the digital divide safely and trustingly: how ecologies of learning scaffold the journey

The article addresses the issue of learning to elearn in borderless programs in a globalised learning landscape and the associated problems of scaffolding the journey across the digital divide. The authors argue that the assumption underlying such courses is that cross-cultural programs are viable because they are conceived and designed to be ‘global’, and that they assume this design to be inclusive. Henning and Van der Westhuizen claim that the global discourse in most domains can take only marginal note of the need to infuse such programs with a local semiotic—a course design criterion for which they argue. They furthermore forward the notion that the majority of the world's prospective elearners need various bridging mechanisms in order to be able to access the broader discourse and that one of these mechanisms can be explored through the metaphor of “information ecologies” as proposed by Nardi and O'Day [Nardi, B.A., & O'Day, V.L. (1999). Information ecologies. Using technology with heart. Cambridge, MA: The MIT Press]. They also conclude that issues of the learners’ trust in the course and its system need to be considered when contemplating programs for diverse target groups. By way of a case study, consisting of three portraitures of adult learners, they explore the limitations of assumed distributed cognition and claim that learning is, in reality, contained/constrained in the familiar local narrative of the novice adult elearners in a rural South African context. The case study illustrates how the resistance to technology and its power base becomes an obstacle for the students and how the support of peers becomes the main scaffolding mechanism for their entry into electronic learning environments. The findings thus show how the social context becomes the facilitator and the scaffold for elearning, more than technology and the curriculum itself.     

Effects of electron beam irradiation on microbial inactivation and quality of kimchi paste during storage

The effects of electron beam irradiation on microbial inactivation and quality of noninoculated and inoculated (Listeria monocytogenes) kimchi pastes were examined. Kimchi paste samples were irradiated at doses of 2, 4, 6, 8 and 10 kGy and stored for 21 days at 4 °C. Irradiation (10 kGy) reduced the populations of total aerobic bacteria, lactic acid bacteria, and yeast and moulds in the samples by 1.72, 2.24 and 0.86 log CFU g^?1, respectively, compared to the control. In particular, coliforms were not detected at 8 and 10 kGy, and the population of L. monocytogenes in inoculated samples was significantly decreased by 2.67 log CFU g^?1. Electron beam irradiation delayed the changes in O₂ and CO₂ concentrations, pH, acidity and reducing sugar content observed in kimchi paste during storage. These results suggest that electron beam irradiation can be used to improve the microbiological safety and shelf life of kimchi paste.     

Attention web designers: You have 50 milliseconds to make a good first impression!

Three studies were conducted to ascertain how quickly people form an opinion about web page visual appeal. In the first study, participants twice rated the visual appeal of web homepages presented for 500 ms each. The second study replicated the first, but participants also rated each web page on seven specific design dimensions. Visual appeal was found to be closely related to most of these. Study 3 again replicated the 500 ms condition as well as adding a 50 ms condition using the same stimuli to determine whether the first impression may be interpreted as a 'mere exposure effect' (Zajonc 1980). Throughout, visual appeal ratings were highly correlated from one phase to the next as were the correlations between the 50 ms and 500 ms conditions. Thus, visual appeal can be assessed within 50 ms, suggesting that web designers have about 50 ms to make a good first impression.