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.     

Evaluating epistemic uncertainty under incomplete assessments

The thesis of this study is to propose an extended methodology for laboratory based Information Retrieval evaluation under incomplete relevance assessments. This new methodology aims to identify potential uncertainty during system comparison that may result from incompleteness. The adoption of this methodology is advantageous, because the detection of epistemic uncertainty – the amount of knowledge (or ignorance) we have about the estimate of a system’s performance – during the evaluation process can guide and direct researchers when evaluating new systems over existing and future test collections. Across a series of experiments we demonstrate how this methodology can lead towards a finer grained analysis of systems. In particular, we show through experimentation how the current practice in Information Retrieval evaluation of using a measurement depth larger than the pooling depth increases uncertainty during system comparison.     

The Relationship Between Teacher Behaviours and Student Talk in Promoting Quality Learning in Science Classrooms

This paper distils 24 years of classroom research into promoting quality learning in science classrooms to develop an overall framework for better understanding and describing both the learning and the teaching approaches that stimulate and support it. For me, quality learning is characterised by adjectives such as informed, purposeful, reflective, intellectually active, metacognitive and independent. Central to quality learning is the role of talk, and central to promoting talk which promotes quality learning are certain teacher behaviours. I first focus on the ways that teachers behave in the classroom in order to promote, react to and use student talk. These behaviours are summed up in a list of twelve principles for quality teaching. Each of these principles requires, as well as appropriate teacher behaviours, the use of effective teaching procedures. I then focus on four kinds of student talk that exemplify informed, purposeful, reflective and intellectually active thinking. These variously involve students’ existing ideas and explanations; increasing student ownership of practical activities; constructive challenges to the teacher (or text’s) idea, and lateral, reflective ‘thinking’ questions.     

Adolescent caregiving success as a predictor of social functioning from ages 13 to 33

Adolescent success providing satisfying support in response to a close friend's call in a caregiving task was examined as a potentially fundamental developmental competence likely to predict future social functioning, adult caregiving security, and physical health. Adolescents (86 males, 98 females; 58% White, 29% African American, 8% mixed race/ethnicity, 5% other) were followed from ages 13 to 33 (1998–2021) using multiple methods and reporters. Early caregiving success was found to predict greater self- and partner-reported caregiving security, lower negativity in adult relationships, and higher adult vagal tone. Results are interpreted as advancing our understanding beyond simply recognizing that adolescent friendships have long-term import, to now identifying specific capacities within friendships that are linked to longer-term outcomes.     

Implicit Theories of Personality and Attributions of Hostile Intent: A Meta‐Analysis,an Experiment,and a Longitudinal Intervention

Past research has shown that hostile schemas and adverse experiences predict the hostile attributional bias. This research proposes that seemingly nonhostile beliefs (implicit theories about the malleability of personality) may also play a role in shaping it. Study 1 meta‐analytically summarized 11 original tests of this hypothesis (N = 1,659), and showed that among diverse adolescents aged 13–16 a fixed or entity theory about personality traits predicted greater hostile attributional biases, which mediated an effect on aggressive desires. Study 2 experimentally changed adolescents' implicit theories toward a malleable or incremental view and showed a reduction in hostile intent attributions. Study 3 delivered an incremental theory intervention that reduced hostile intent attributions and aggressive desires over an 8‐month period.     

Teacher Evaluation in an Era of Educational Change

Teachers can help minority children close the academic achievement gap in intermediate and middle school by combining literacy instruction and content-area material. This connection improves reading achievement and increases curriculum knowledge, even if students have previously experienced difficulty with primary school reading. Fortunately, upper-elementary and middle-level learners are still naturally curious, are developing cognitively, and have acquired some basic reading skills. Teachers can therefore extend students' previous learning by using a spiral curriculum, in which curricular concepts are introduced at an appropriate level and then revisited at more challenging levels. Teachers can also increase the academic complexity for students by using strategies that include picture books, word recognition skills, intensive subject matter, vocabulary in a meaningful context, Readers Theater, and after-school activities.