Semi-local Quantum Criticality and the Instability of Extremal Planar Horizons

We show that the Aretakis instability of compact extremal horizons persists in the planar case of interest to holography and discuss its connection with the emergence of "semi-local quantum criticality" in the field theory dual. In particular, the spatially localized power-law decay of this critical phase corresponds to spatially localized power-law growth of stress-energy on the horizon. For near-extremal black holes these phenomena occur transiently over times of order the inverse temperature. The boundary critical phase is characterized by an emergent temporal conformal symmetry, and the bulk instability seems to be essential to preserving the symmetry in the presence of interactions. We work primarily in the solvable example of charged scalar perturbations of five-dimensional (near-)extremal planar Reissner-Nordstr\"om anti-de Sitter spacetime and argue that the conclusions hold more generally.Comment: 23 pages. v2 contains a reference updat

Core Reflection as Self-Fulfilling Prophecy: Implications for Teacher Education

In this commentary, I explore a method of teacher reflection developed by Korthagen and colleagues, which they refer to as “core reflection” (Korthagen, Kim, & Green, 2013). Specifically, I have noticed that the process of “core reflection” bears a strong resemblance to self-fulfilling prophecies and other “placebo effects” observed in many medical and psychological studies (Price, Finniss, & Benedetti, 2008). It may be the case that this particular brand of teacher reflection is effective, not because teachers actually possess particular character strengths or virtues (as the method supposes), but because core reflection functions as a self-fulfilling prophecy: i.e., expectations bring forth changes in behavior. If, indeed, core reflection functions in this way, this insight has implications for teacher reflection and teacher education

Expanding the Scope of Teacher Education in an Attempt to Prevent Burnout Contagion

Burnout is a significant problem that continues to plague the teaching profession. In this essay, I argue that the burnout of early-career teachers is not solely a function of personal factors (e.g., their knowledge, their beliefs, their pedagogical skills, their commitment to the teaching profession) but also a function of the organizational climates into which these early-career teachers enter. Specifically, burnout can be contagious, and, therefore, I argue that teacher educators must expand the scope of their efforts to include not only educating individual pre-service teachers but also revitalizing the organizational climates present within local schools

Knots in Thinking and the Problem of Enactment: Exploring the Classroom Thinking of Three Novice Teachers

Novice teachers begin their careers with certain instructional ideals; however, in practice, novice teachers tend to enact classroom practices that only partially align with these ideals—a phenomenon referred to as the problem of enactment. This article explores this phenomenon by investigating the classroom thinking of three novice teachers. Using stimulated-recall interviews, these teachers were asked to describe the deliberative decisions they made while teaching and to rate how well these decisions aligned with their instructional ideals. It was found that when novice teachers perceived only partial alignment between their enacted decisions and their instructional ideals, teachers tended to experience simultaneous practical intentions. I argue that, as teacher educators attempt to address the problem of enactment, they must deepen their appreciation for the cognitive challenge of balancing simultaneous practical intentions. The real-time negotiation between multiple goals and concerns can be considered to be a core practice of teaching

The End of College: Creating the Future of Learning and the University of Everywhere

Book Revie

Scaling and Universality in Extremal Black Hole Perturbations

We show that the emergent near-horizon conformal symmetry of extremal black holes gives rise to universal behavior in perturbing fields, both near and far from the black hole horizon. The scale-invariance of the near-horizon region entails power law time-dependence with three universal features: (1) the decay off the horizon is always precisely twice as fast as the decay on the horizon; (2) the special rates of $1/t$ off the horizon and $1/\sqrt{v}$ on the horizon commonly occur; and (3) sufficiently high-order transverse derivatives grow on the horizon (Aretakis instability). The results are simply understood in terms of near-horizon ($\mathrm{AdS}_2$) holography. We first show how the general features follow from symmetry alone and then go on to present the detailed universal behavior of scalar, electromagnetic, and gravitational perturbations of $d$-dimensional electrovacuum black holes.Comment: 31 pages. v3 matches published versio

Atmospheric Moisture Content Effects on Ionic Liquid Wettability of Alumina

The contact angles or wettability of 7 Ionic Liquids, on an alumina substrate, have been measured under two different storage conditions. The first using a small amount of moisture content, the second with no moisture content. The contact angle of Ionic Liquid droplets on an alumina substrate were measured using an Attension Theta instrument with automated software. The results show that a small amount of moisture improves the wettability of the Ionic Liquid – alumina system and therefore subsequent uses of these liquids with alumina should take this into consideration