Concurrent droplet charging and sorting by electrostatic actuation

This paper presents a droplet-based microfluidic device for concurrent droplet charging and sorting by electrostatic actuation. Water-in-oil droplets can be charged on generation by synchronized electrostatic actuation. Then, simultaneously, the precharged droplets can be electrostatically steered into any designated laminar streamline, thus they can be sorted into one of multiple sorting channels one by one in a controlled fashion. In this paper, we studied the size dependence of the water droplets under various relative flow rates of water and oil. We demonstrated the concurrent charging and sorting of up to 600 droplets∕s by synchronized electrostatic actuation. Finally, we investigated optimized voltages for stable droplet charging and sorting. This is an essential enabling technology for fast, robust, and multiplexed sorting of microdroplets, and for the droplet-based microfluidic systems.     

Size-dependent trajectories of DNA macromolecules due to insulative dielectrophoresis in submicrometer-deep fluidic channels

In this paper, we demonstrate for the first time that insulative dielectrophoresis can induce size-dependent trajectories of DNA macromolecules. We experimentally use λ (48.5 kbp) and T4GT7 (165.6 kbp) DNA molecules flowing continuously around a sharp corner inside fluidic channels with a depth of 0.4 μm. Numerical simulation of the electrokinetic force distribution inside the channels is in qualitative agreement with our experimentally observed trajectories. We discuss a possible physical mechanism for the DNA polarization and dielectrophoresis inside confining channels, based on the observed dielectrophoresis responses due to different DNA sizes and various electric fields applied between the inlet and the outlet. The proposed physical mechanism indicates that further extensive investigations, both theoretically and experimentally, would be very useful to better elucidate the forces involved at DNA dielectrophoresis. When applied for size-based sorting of DNA molecules, our sorting method offers two major advantages compared to earlier attempts with insulative dielectrophoresis: Its continuous operation allows for high-throughput analysis, and it only requires electric field strengths as low as ∼10 V∕cm.     

Supervision and evaluation: The Wyoming perspective

The intent of this study was to assess the perceptions and actions of Wyoming principals concerning their role in supervising and evaluating teachers. A survey was sent to all 286 principals in the state of Wyoming, of which, 143 returned surveys, a response rate of 50%. Findings suggested that principals utilized supervisory behaviors more often than evaluative behaviors. Elementary principals perceived their evaluative practices as significantly more prevalent than secondary principals. Furthermore, principals indicated that their greatest frustrations in supervising teachers were time, the evaluation instrument, and teachers’ unwillingness to change. Additionally, findings suggested that Wyoming principals utilized classroom walkthroughs because they provided a snapshot of teaching and provided a medium for providing feedback. In regards to developmental supervision, principals indicated that novice teachers received much more supervision than veteran teachers. However, their reported use of differentiated supervision only applied to teacher autonomy concerning professional development goals. Principals reported that teachers had little input concerning the methods by which they were supervised. Finally, a majority of the Wyoming principals felt that improvement plans were effective at changing mediocre teaching behaviors, but 40% were speculative that such plans truly remediated poor teachers.     

Reflection on the education policy orientation in post-May 31 reform in Korea

For the last 70 years, since the establishment of the Republic of Korea, Korean education has achieved universal expansion of educational opportunity from elementary to secondary to higher education. Planning, centralized policy making, top-down implementation, and administrative control had been the standards of the first few decades of Korean education. The so-called May 31 education reform implemented in 1995 made a turning point for these approaches to education policy and administration by highlighting autonomy, openness, diversity, accountability, consumer centeredness, market control, and governance for quality education. However, these government-driven education reform initiatives have resulted in limiting the expected outcomes. In this paper, the authors call for a new approach to education policy and administration and propose supporting school innovation, empowering an internal accountability system in governance. The authors also suggest a search for normative values for democratic communitarianism as a new philosophical foundation of education policy framework, beyond instrumental values of education.     

The emerging landscape of school-based professional learning communities in South Korean schools

Abstract

Over the last decade, school-based professional learning communities (PLCs) have emerged as a key feature of the education system in South Korea. To understand this relatively new phenomenon in the context of South Korea, we provide a review of research on school-based PLCs in South Korea and an empirical analysis of the Teaching and Learning International Survey (TALIS) 2008 with a focus on school-based PLCs. Based on our findings from the literature review and analysis of the TALIS, we aim to provide a fuller picture of the emerging landscape of school-based PLCs in South Korean schools. In so doing, we focus on what constitutes school-based PLCs in South Korean schools and how they are similar to and/or different from their counterparts in other countries. Implications for policy, practice, and research are discussed.     

The de/politicization of pronouns: implications of the No Big Deal Campaign for gender-expansive educational policy and practice

ABSTRACT

Accommodating non-binary transgender people, many of whom use gender-neutral pronouns, poses a unique challenge to schools and universities, even in contexts with legal protections for transgender rights. This article explores a recent Canadian controversy around gender-neutral pronouns, and assembles a theoretical framework to analyze the argument that legal protection for transgender peoples’ pronouns poses a threat to ‘free speech.’ The framework bridges queer theory, affect theory and Deleuzo-Guattarian assemblage theory to propose a threshold between ‘extra’ and ‘excessive’ effort to accommodate social difference in everyday life. Free speech objections produce some peoples’ pronouns as requiring ‘excessive’ effort. This extra/excessive framework was exemplified by a recent Canadian social media campaign that sought to produce transgender peoples’ pronouns as requiring merely ‘extra’ effort, which entails de-politicizing pronouns. Community responses to the campaign carry significant implications for gender-expansive educational policy and practice.     

Self-concept of students in higher education: are there differences by faculty and gender?

Many studies examine student self-concept during compulsory schooling but few have explored the self-concept of students in higher educational settings. The current study examined self-concept by faculty and gender among higher education students in New Zealand. Participants were 929 undergraduate students from a large New Zealand university. The results showed some differences in verbal and maths self-concept by faculty. Generally, students in faculties teaching subjects more reliant on maths skills had higher maths self-concept than those in faculties where facility in verbal skills was important. The opposite results were found for verbal self-concept. No overall gender differences were found for general, academic, verbal and maths self-concept although a statistically significant difference was found for problem-solving self-concept. This finding suggests students’ choice of faculty may be based on perceptions of their skills and capabilities in the various fields, irrespective of gender.     

Leadership of older adults’ service learning in Taiwan: a qualitative study

ABSTRACT

In Taiwan, there are service learning programs organized by older adult educational institutions that are held in high esteem. Director leadership plays a key role in the effectiveness of such institutions, and the leadership experiences of such directors in guiding service learning are worth exploring. This study conducted a qualitative approach and selected directors from eight Active Aging Learning Centers (AALCs) who achieved outstanding leadership effectiveness to take part in one-on-one and in-depth semi-structured interviews. The results indicated that: 1. Directors infused the entire service learning process with inspirational motivation by adopting through individualized consideration as a starting point. 2. When directors led the preparation process for service learning, they focused on inducing intellectual stimulation among the older adult learners, such that they felt empowered and capable of providing community services. 3. During the community service phase, directors practiced a form of leadership characterized by idealized influence to encourage, accompany, and support the elderly while they engaged in service learning. 4. The dilemma faced by directors was dissatisfaction with the leadership. Directors responded by reminding them of their original service learning intention and downplaying issues, which made the service learning group undergo a positive transformation. 5. The results of directors’ leadership had a positive effect on the community as it led to more dynamism and more people participating in community service.