Persistent current formation in a high-temperature Bose-Einstein condensate: an experimental test for c-field theory

Experimental stirring of a toroidally trapped Bose-Einstein condensate at high temperature generates a disordered array of quantum vortices that decays via thermal dissipation to form a macroscopic persistent current [T. W. Neely em et al. arXiv:1204.1102 (2012)]. We perform 3D numerical simulations of the experimental sequence within the Stochastic Projected Gross-Pitaevskii equation using ab initio determined reservoir parameters. We find that both damping and noise are essential for describing the dynamics of the high-temperature Bose field. The theory gives a quantitative account of the formation of a persistent current, with no fitted parameters.Comment: v2: 7 pages, 3 figures, new experimental data and numerical simulation

INVISQUE as a tool for intelligence analysis: the construction of explanatory narratives

We report an exploratory user-study in which a group of civil servants with experience of, or involvement in, intelligence analysis used the tool INVISQUE to address a problem using the 2011 VAST dataset. INVISQUE uses a visual metaphor that combines searching, clustering and sorting of document surrogates with free-form manipulation on an infinite canvas. We were interested in exposing the behaviours and related cognitive strategies that users would employ to better understand how this and similar environments might better support intelligence type work. Our results include the observation that the search and spatial features of the system supported participants in establishing, elaborating and systematically evaluating explanatory narratives that accounted for the data. Also, visual persistence at the interface allowed them to keep track of searches and to re-find documents when their importance became apparent. We conclude with reflections on our findings and propose a set of guidelines for developing systems that support sensemaking

Suppression of Kelvon-induced decay of quantized vortices in oblate Bose-Einstein Condensates

We study the Kelvin mode excitations on a vortex line in a three-dimensional trapped Bose-Einstein condensate at finite temperature. Our stochastic Gross-Pitaevskii simulations show that the activation of these modes can be suppressed by tightening the confinement along the direction of the vortex line, leading to a strong suppression in the vortex decay rate as the system enters a regime of two-dimensional vortex dynamics. As the system approaches the condensation transition temperature we find that the vortex decay rate is strongly sensitive to dimensionality and temperature, observing a large enhancement for quasi-two-dimensional traps. Three-dimensional simulations of the recent vortex dipole decay experiment of Neely et al. [Phys. Rev. Lett. 104, 160401 (2010)] confirm two-dimensional vortex dynamics, and predict a dipole lifetime consistent with experimental observations and suppression of Kelvon-induced vortex decay in highly oblate condensates.Comment: 8 pages, 8 figure

An Investigation into the Role of Coping in Preventing Depression Associated with Perfectionism in Preadolescent Children

The relationships between self-oriented and socially prescribed perfectionism (SPP) and maladaptive and adaptive coping strategies and their collective impact on depression symptoms were examined in the context of a randomized controlled universal trial of the Aussie Optimism Positive Thinking Skills Program. Five hundred and forty-one children aged 8-12 completed a battery of self-reports, of which responses for measures of depression symptoms, perfectionism, and coping strategies were examined for the purposes of this study. Structural equation modeling tested whether coping mediated the effects of perfectionism on depression. Results indicated that SPP had both a direct and an indirect relationship with depression symptoms through a moderate association with maladaptive coping. Implications for prevention of depression were discussed and recommendations for future research were proposed

Trialling the SMART approach: identifying and assessing sense-making

It is important to develop tools that support sense-making by providing representations that help to capture the externalisation of the thinking process. The paper focuses on a new method for identifying the sense-making processes of experts by combing probes with cognitive task analysis methods. The data-frame sense-making model is used as a theoretical frame, and the probes have been developed around the model to elicit experts’ sense-making. However, in the analysis proceeding a sense-making task, the developed probes by themselves were unable to capture the experts sense-making and a stronger emphasis of cognitive task analysis methods and observations were required to interpret the findings