Teachers' pedagogical beliefs and their planning and conduct of computer-mediated classroom lessons

In this study, we observed and interviewed six teachers from two Singapore primary school classrooms. The schools were reportedly achieving high levels of computer integration as reflected in a nationwide questionnaire survey. Out of the 18 lessons that we observed, 14 lessons have incorporated some elements of constructivist teaching. However, closer examination revealed that the underlying orientation of the lessons was inclined towards information acquisition and regurgitation. Five out of the six teachers we interviewed were reportedly inclined towards constructivist notion of teaching. The teachers accounted for the inconsistency between their espoused beliefs and the teacher-centric teaching practice as due to contextual constraints. The teachers expressed that the need to complete the syllabi according to stipulated schedules so as to get the students ready for examination was the main barriers that prevented them from engaging in more constructivist teaching. This case study therefore highlights that although it is necessary for teachers to hold pedagogical beliefs that are compatible with the constructivist notion of teaching and learning, this is an insufficient condition to shift traditional teaching practice. Changes in assessment systems and substantial professional development are further conditions that have to be addressed.     

The influence of temperature and humidity on swelling and surfactant migration in acrylic emulsion paint films

It has often been observed anecdotally and implied through experimentation that acrylic emulsion paintings accumulate and entrain soils over time due to the inherent mechanical softness in artist's acrylic paint films, through the presence of hydrophilic film components, and by virtue of the ubiquitous presence of surfactant moieties on these film surfaces once they dry. In the present study, it has been this last effect that we have sought to describe more fully in terms of surfactant responsiveness to both temperature and relative humidity (RH). Surfactant hydration and dehydration under varying temperature and RH conditions affects the ultimate partitioning of the surfactant at the paint–air interface, as well as the inherent size, aggregation tendencies, and solubility of surfactant in the bulk paint materials which contain components that are highly responsive to changes in temperature and RH (e.g. polyacrylic or polymaleic anhydride-type dispersal materials). In this work, analytical techniques including three-dimensional microscopy and quartz crystal microbalance with dissipation were used to add to and reinforce current understanding of the physical and mechanical changes to acrylic paint films with temperature and RH. The migration of surfactant at the film surface was studied using desorption electrospray ionization-mass spectrometry and attenuated total reflectance Fourier transform infrared microscopy.     

中国蕨类植物的一些新分类群

在编写《中国植物志》第五卷过程中,发现三叉蕨科、实蕨科和藤蕨科的一些新分类群,预  先发表。模式标本均存中国科学院植物研究所。      

中国盾蕨属的订正研究

 本文根据近四十年来积累的丰富标本材料,对盾蕨属Neolepisorus Ching分  类的正确与否进行了研究。  本属从原来只有3个种的一个小属发展到今天的  11个种的中等属,有力地说明了我国植物资源的丰富,并从一个侧面反映了四  十年代以来我国植物分类学研完取得了巨大进展。  特别有意义的是,这个属的  许多种各自显示着形态变异的多样性,即一个种的叶型往往从正常的全缘单叶  能发展为各种不同程度的畸形分裂,对它们分类上的鉴定造成一定的困难,同  时,对他们的形态发生的研究也提供了一个新课题。