High efficiency vortex trapping of circulating tumor cells

Circulating tumor cells (CTCs) are important biomarkers for monitoring tumor dynamics and efficacy of cancer therapy. Several technologies have been demonstrated to isolate CTCs with high efficiency but achieve a low purity from a large background of blood cells. We have previously shown the ability to enrich CTCs with high purity from large volumes of blood through selective capture in microvortices using the Vortex Chip. The device consists of a narrow channel followed by a series of expansion regions called reservoirs. Fast flow in the narrow entry channel gives rise to inertial forces, which direct larger cells into trapping vortices in the reservoirs where they remain circulating in orbits. By studying the entry and stability of particles following entry into reservoirs, we discover that channel cross sectional area plays an important role in controlling the size of trapped particles, not just the orbital trajectories. Using these design modifications, we demonstrate a new device that is able to capture a wider size range of CTCs from clinical samples, uncovering further heterogeneity. This simple biophysical method opens doors for a range of downstream interventions, including genetic analysis, cell culture, and ultimately personalized cancer therapy.     

Re-examining the effects of adding relevance information in a relevance feedback environment

This paper presents an investigation about how to automatically formulate effective queries using full or partial relevance information (i.e., the terms that are in relevant documents) in the context of relevance feedback (RF). The effects of adding relevance information in the RF environment are studied via controlled experiments. The conditions of these controlled experiments are formalized into a set of assumptions that form the framework of our study. This framework is called idealized relevance feedback (IRF) framework. In our IRF settings, we confirm the previous findings of relevance feedback studies. In addition, our experiments show that better retrieval effectiveness can be obtained when (i) we normalize the term weights by their ranks, (ii) we select weighted terms in the top K retrieved documents, (iii) we include terms in the initial title queries, and (iv) we use the best query sizes for each topic instead of the average best query size where they produce at most five percentage points improvement in the mean average precision (MAP) value. We have also achieved a new level of retrieval effectiveness which is about 55–60% MAP instead of 40+% in the previous findings. This new level of retrieval effectiveness was found to be similar to a level using a TREC ad hoc test collection that is about double the number of documents in the TREC-3 test collection used in previous works.     

Chinese primary school mathematics teachers working in a centralised curriculum system: a case study of two primary schools in North‐East China

Mainland China has a highly centralised curriculum development system. A study of two schools in northeast China, one in a rural area and the other in an urban area, indicates that the primary mathematics curriculum has been widely adopted by teachers at the classroom level. Feeling the intense pressure generated by the national mathematics Olympiad,1 1. The mathematics Olympiad is a type of ‘extracurricular’ activity that aims to promote students' interest and improve their ability in mathematics. Students participating in the competition are required to complete some challenging and non‐routine mathematical operations. The international mathematics Olympiad is held every year. In Mainland China, this competition is commonly organised at city, provincial and national level. Students who perform exceptionally well are exempted from the highly competitive national university entrance examinations for entry to universities View all notes teachers in the urban school tended to give more difficult mathematics problems to their students in the hope that above‐average students would perform well in the competition. In the rural school, the ability of students was more varied and generally lower. Teachers there worked very hard to push their students to meet the national requirements. The driving force behind this was the county‐wide public examination in which students' performance was taken as an indicator of teachers' competence. Teachers in both schools also have not taken effective steps to adapt the curriculum for students' individual differences. A comparison of the practices between the teachers in the two schools suggests that teachers' beliefs, their professional knowledge and skills shape their inclination and ability in curriculum adaptation and differentiation.     

Research Report RECSAM: Computers in Education Project,Singapore Study

From 1986 to 1988, Regional Centre for Education in Science and Mathematics (RECSAM) at Penang organised the Computers in Education Project with financial support from the Australian Government. The aim of the Project was to provide information on the use of computers in education among SEAMEO countries. Such information, it was thought, could be useful for educators who needed to formulate sound policies regarding the introduction, management, and use of computers in schools and the roles of computers in education in general. Six countries took part in this project including a team from Singapore.     

Leptotrichia hongkongensis sp. nov., a novel Leptotrichia species with the oral cavity as its natural reservoir

A straight, non-sporulating, Gram-variable bacillus (HKU24T) was recovered from the blood culture of a patient with metastatic breast carcinoma. After repeated subculturing in BACTEC Plus Anaerobic/F blood culture broth, HKU24T grew on brucella agar as non-hemolytic, pinpoint colonies after 96 h of incubation at 37 °C in an anaerobic environment and aerobic environment with 5% CO2. Growth was enhanced with a streak of Staphylococcus aureus. HKU24T was non-motile and catalase-negative, but positive for alkaline phosphatase, β-glucosidase, and α-glucosidase. It hydrolyzed phenylphosphonate and reduced resazurin. 16S rRNA, groEL, gyrB, recA, and rpoB sequencing showed that HKU24T occupies a distinct phylogenetic position among the Leptotrichia species, being most closely related to Leptotrichia trevisanii. Using HKU24T groEL, gyrB, recA, and rpoB gene-specific primers, fragments of these genes were amplified from one of 20 oral specimens. Based on phenotypic and genotypic characteristics, we propose a new species, Leptotrichia hongkongensis sp. nov., to describe this bacterium.     

A Pilot Study to Identify Comparison Schools for Math and Science Partnership Participating Schools: Preliminary Findings on One Math/Science Partnership

This pilot study proposes a set of analytical steps for comparing schools that participate in the National Science Foundation's Math and Science Partnership (MSP) Program and their nonparticipating peers in the same state. This pilot is part of a larger effort to evaluate the MSP Program's role in student achievement, with two companion analyses. Although our pilot study uses a comparative approach, the study by Dimitrov in this issue follows a within-group design. The third analysis by Yin and his associates in this issue covers the varied designs used by the MSPs themselves in their own evaluations.

In this pilot, we focus on a sample of participating schools in one MSP in one state. The nonparticipating schools were carefully matched with the program participating schools on eight demographic variables to form a comparison group. This article offers detailed documentation on how we operationalize two matching methods for comparative purpose. We conclude that carefully executed matching methods are promising for large scale comparative analysis on the effects of the MSP Program across different states.     

Beginning teachers' understanding performances of technology integration

As part of a two-year, mixed methods study, the focus of this paper reports the qualitative findings that are related to nine beginning teachers' learning to teach with Information and Communication Technology (ICT) during their first year of teaching. It aims to explore how these teachers deepen their understanding performances of technology integration in their first year. They demonstrated consistent, varied perceptions, frequency and ways of using ICT for classroom teaching and learning from their initial teacher education to their first year teaching. They developed diverse understandings of technology integration from their own practice, and chose to play different roles, such as, follower, doer and emerging teacher leader for technology integration. Suggestions to schools on providing beginning teachers with ongoing technical and pedagogical support and capitalizing on their tech-savvy strengths are discussed.     

Metacognitive development and moving away

It is now largely accepted that social and cultural factors have a significant impact on cognitive development in children. Piaget acknowledged the impact of social factors and peer interaction on cognitive development. However, there has been relatively little work on the impact of social and cultural factors on the development of metacognition in first‐year university students. Using the Learning and study strategies inventory (LASSI) as a measure of metacognition, this study samples first‐year undergraduates in Hong Kong (N = 1815) and identifies significant differences in metacognitive abilities between students living in their home environment and those who have moved away from their family and, in some cases, culture, to pursue undergraduate education.     

Automatic indexing using term discrimination and term precision measurements

A variety of abstract automatic indexing models have been developed in recent times in an effort to produce indexing methods that are both effective and usable in practice. Among these are the term discrimination model and the term precision system. These two indexing systems are briefly described and experimental evidence is cited showing that a combination of both theories produces better retrieval performance than either one alone. Appropriate conclusions are reached concerning viable automatic indexing procedures usable in practice.     

College Admissions,International Competition,and the Cold War in Asia: The Case of Overseas Chinese Students in Taiwan in the 1950s

Focusing only on education exchanges between the United States and other countries, existing scholarship fails to illuminate how American‐sponsored student migrations between other countries helped expand U.S. hegemony. This article attempts to rectify this limitation by looking at Taiwan's policies on overseas Chinese students (qiaosheng) in the 1950s. After the debacle of the Chinese Civil War and its retreat to Taiwan, the Kuomintang (KMT) sought to solicit overseas Chinese support and to counter Communist China's drive for “returning students.” The KMT‐developed qiaosheng program faced difficulties until 1954, when the United States, seeing that Taiwan's project could serve its anti‐Communist plan, started bankrolling the qiaosheng program, thereby enabling the KMT to lure more students away from Communist China. These findings suggest that overlooking U.S.‐sponsored student migrations between nations outside the United States renders our analysis of international education exchanges and American imperialism incomplete.