Numerical study of dc-biased ac-electrokinetic flow over symmetrical electrodes

This paper presents a numerical study of DC-biased AC-electrokinetic (DC-biased ACEK) flow over a pair of symmetrical electrodes. The flow mechanism is based on a transverse conductivity gradient created through incipient Faradaic reactions occurring at the electrodes when a DC-bias is applied. The DC biased AC electric field acting on this gradient generates a fluid flow in the form of vortexes. To understand more in depth the DC-biased ACEK flow mechanism, a phenomenological model is developed to study the effects of voltage, conductivity ratio, channel width, depth, and aspect ratio on the induced flow characteristics. It was found that flow velocity on the order of mm/s can be produced at higher voltage and conductivity ratio. Such rapid flow velocity is one of the highest reported in microsystems technology using electrokinetics.     

What are the affective and social outcomes for low-achieving students within an inclusive school in Hong Kong?

In response to several major curriculum reforms in Hong Kong since 2000, schools were required to initiate policies that catered for learner diversity. As well academic achievement, the reforms also emphasized the affective and social outcomes of the learning experience. A whole-school approach to learner diversity includes students with low academic achievement and mild disabilities, with schools being free to develop policies and practices inline with the needs of the students, teachers, and parents. Against the Chinese cultural context, where high academic achievement is highly valued, this study describes the affective and social outcomes of students in one Hong Kong primary school that streamed students according to achievement level. Four hundred and ten students across Primary 3–5 responded to four instruments measuring academic self-concept, alienation from school, teacher–students relationship, and social integration. The responses showed that, when studying the regular curriculum, students in the low-achievement group reported greater levels of alienation and lowest levels of social integration compared with students with the highest levels of achievement. On the other hand, low-achieving students who studied a differentiated curriculum reported affective and social outcomes more consistent with the responses from the high-achieving students. The results suggest that there is a mismatch between the aims and practice of the educational policy reflecting learner diversity and the cultural expectations of both parents and students.     

A microfluidic membrane device to mimic critical components of the vascular microenvironment

Vascular function, homeostasis, and pathological development are regulated by the endothelial cells that line blood vessels. Endothelial function is influenced by the integrated effects of multiple factors, including hemodynamic conditions, soluble and insoluble biochemical signals, and interactions with other cell types. Here, we present a membrane microfluidic device that recapitulates key components of the vascular microenvironment, including hemodynamic shear stress, circulating cytokines, extracellular matrix proteins, and multiple interacting cells. The utility of the device was demonstrated by measuring monocyte adhesion to and transmigration through a porcine aortic endothelial cell monolayer. Endothelial cells grown in the membrane microchannels and subjected to 20 dynes∕cm(2) shear stress remained viable, attached, and confluent for several days. Consistent with the data from macroscale systems, 25 ng∕ml tumor necrosis factor (TNF)-α significantly increased RAW264.7 monocyte adhesion. Preconditioning endothelial cells for 24 h under static or 20 dynes∕cm(2) shear stress conditions did not influence TNF-α-induced monocyte attachment. In contrast, simultaneous application of TNF-α and 20 dynes∕cm(2) shear stress caused increased monocyte adhesion compared with endothelial cells treated with TNF-α under static conditions. THP-1 monocytic cells migrated across an activated endothelium, with increased diapedesis in response to monocyte chemoattractant protein (MCP)-1 in the lower channel of the device. This microfluidic platform can be used to study complex cell-matrix and cell-cell interactions in environments that mimic those in native and tissue engineered blood vessels, and offers the potential for parallelization and increased throughput over conventional macroscale systems.     

Instructional practices and science performance of 10 top-performing regions in PISA 2015

ABSTRACT

This study analysed 10 top-performing regions in PISA 2015 on their science performances and instructional practices. The regions include Singapore, Japan, Estonia, Taipei, Finland, Macao, Canada, Hong Kong, China and Korea. The science performances of the 10 regions and their teaching practices are described and compared. The construct of enquiry-based instruction as developed in PISA 2015 is revised into two new constructs using factor analysis. Then, the relationships of the teaching practices with science performance are analysed using hierarchical linear modelling. Adaptive instruction, teacher-directed instruction and interactive application are found positively associated with performance in all regions, while investigation and perceived feedback are all negative. The regions except Japan and Korea tend to have a high frequency of teacher-directed instruction facilitated by more or less authoritative class discussion in class. A fair amount of practical work is done, but not many of them are investigations. The cultural influences on teaching practices are discussed on how an amalgam of didactic and constructivist pedagogy is created by the Western progressive educational philosophy meeting the Confucian culture. The reasons for investigation’s negative association with performance are also explored.     

Hong Kong-based TEFL/TESOL global academics: life,culture, mobility,globalisation and cosmopolitanism

This paper is about a qualitative research concerning a group of expatriates' (TEFL/TESOL English language teachers) experiences in Hong Kong. Data related to their life, attitudes and cultural dispositions are discussed under four different states, namely, Adaptation, Drifting in Global Comfort, Drifting in Global Discomfort and Bitter/Sweet Home. Together, these contribute to their mobility pattern – the Global Drift. The study discusses their global experiences and situations relating to the interplay of personal choice on the one hand and changing global and local processes and conditions on the other. It is argued that this is a self-perpetuating group sustained and reproduced by a Global Quality including distinct cultural dispositions, concepts of home and the reproduction of third-culture-kids, who are tailor-made for twenty-first-century mobile work. Finally, the research is situated in the study of cosmopolitanism, particularly in the identification of cosmopolitans and their dispositions. Alternative ways of theorising home (as interactive continuums) and issues related to mobility and dispositions will be discussed briefly.     

Visuomotor integration and executive functioning are uniquely linked to Chinese word reading and writing in kindergarten children

This cross-sectional study examined the associations of visuomotor integration and executive functioning with Chinese word reading and writing in kindergarten children. A total of 369 Chinese children (mean age = 57.99 months; 55% of them were girls) from Hong Kong, China, completed tasks on visuomotor integration, executive functioning, and Chinese word reading and writing. Children also completed tasks on rapid automatized naming, and their mothers provided child and family background information. Hierarchical regression analyses revealed that, controlling for child age, gender, and rapid automatized naming and maternal education, both visuomotor integration and executive functioning were uniquely linked to Chinese word reading and writing. Findings highlighted the importance of visuomotor integration and executive functioning in understanding the development of Chinese word reading and writing in early years, and the utility of targeting visuomotor integration and executive functioning to help kindergarten children to learn to read and write in Chinese.     

Inquiry Science Learning and Teaching: a Comparison Between the Conceptions and Attitudes of Pre-service Elementary Teachers in Hong Kong and the United States

Research in Science Education - International studies of science education, such as the Trends in Mathematics and Science Study (TIMSS), have revealed considerable national disparities in...     

Effects of social persuasion from parents and teachers on Chinese students’ self-efficacy: an exploratory study

This study compared the effects of social persuasion from parents and teachers on students’ self-efficacy in reading comprehension in English as a foreign language. Ninety-nine Grade 8 Chinese students in a secondary school in Hong Kong completed a questionnaire with six scenarios which tapped their self-efficacy after receiving positive and negative feedback that were described as coming from their teacher, mother and father. Students decreased their self-efficacy after receiving negative feedback and the source of feedback did not make a statistically significant difference. Conversely, positive feedback led to an increase in self-efficacy with the mother’s positive feedback leading to a higher increase in self-efficacy than feedback from the teacher and the father. No statistically significant difference was noted in the change in self-efficacy after receiving feedback from the father and the teacher. Parents and teachers should increase the use of positive feedback and decrease that of negative feedback. Implications for collaboration between teachers and parents in providing positive feedback on students’ academic performance were discussed.     

Do reading practices make a difference? Evidence from PIRLS data for Hong Kong and Taiwan primary school Grade 4 students

This study examined the influence of classroom pedagogic reading practices and out-of-school practices in explaining why the reading attainment of Hong Kong Grade 4 students was superior to that of their counterparts in Taiwan in the 2006 Progress in International Reading Literacy Study. Analyses of scores from 9301 students (4712 from Hong Kong and 4589 from Taiwan) revealed that independent reading in school made a distinctive contribution to the reading performance of Hong Kong and Taiwan students after controlling for the effects of students’ and parents’ reading attitudes, the availability of supportive home educational resources and student engagement in a range of reading practices. Out-of-school informational reading was found to be negatively associated with students’ reading attainment for both Hong Kong and Taiwan students. There was evidence that reading aloud in class in Taiwan classrooms significantly contributed to the Taiwan students’ poor reading performance.     

Enacting feedback utilization from a task-specific perspective

Feedback is central to successful teaching and learning. Despite extensive research on the relationship between feedback, pedagogy and learning, there remain no conclusive answers as to how feedback can be effectively utilized by learners. Recently, there is emerging research exploring how feedback is conceptualized as dialogic processes to facilitate provision and uptake of feedback; and how feedback utilization is best supported by learner active involvement in the iterative feedback process for future learning. Drawn from this knowledge base, this article aims to review four aspects of feedback scholarship including nature, paradigms, issues and trends which serve as a theoretical basis, together with instructors’ interviews, to inform how five common assessment tasks in one social sciences faculty could be strategically revamped to promote feedback utilization. The article concludes with pedagogical insights to suggest three conditions wherein feedback could be made sustainable to support learning through a redesigning of conventional assessment tasks in the higher education contexts.