2,373 research outputs found

    Structure and play: rethinking regulation in the higher education sector

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    This paper explores possible tactics for academics working within a context of increasing regulation and constraint. One suggested tactic is to move outside of a creativity-conformity binary. Rather than understanding creativity and conformity as separable, where one is seen as excluding the other, the authors consider the potential of examining the relationships between them. The theme of 'structure and play' illustrates the argument. In the first part of the paper, using various examples from art and design - fields generally associated with creativity - the authors explore the interrelatedness of creativity and conformity. For example, how might design styles, which are generally understood as creative outcomes, constrain creativity and lead to conformity within the design field? Is fashion producing creativity or conformity? Conversely, the ways in which conformity provides the conditions for creativity are also examined. For example, the conformity imposed by the state on artists in the former communist bloc contributed to a thriving underground arts movement which challenged conformity and state regulation. Continuing the theme of 'structure and play', the authors recount a story from an Australian university which foregrounds the ongoing renegotiation of power relations in the academy. This account illustrates how programmatic government in a university, with its aim of regulating conduct, can contribute to unanticipated outcomes. The authors propose that a Foucauldian view of distributed power is useful for academics operating in a context of increasing regulation, as it brings into view sites where power might begin to be renegotiated

    Evidence of Skyrmion excitations about ν=1\nu =1 in n-Modulation Doped Single Quantum Wells by Inter-band Optical Transmission

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    We observe a dramatic reduction in the degree of spin-polarization of a two-dimensional electron gas in a magnetic field when the Fermi energy moves off the mid-point of the spin-gap of the lowest Landau level, ν=1\nu=1. This rapid decay of spin alignment to an unpolarized state occurs over small changes to both higher and lower magnetic field. The degree of electron spin polarization as a function of ν\nu is measured through the magneto-absorption spectra which distinguish the occupancy of the two electron spin states. The data provide experimental evidence for the presence of Skyrmion excitations where exchange energy dominates Zeeman energy in the integer quantum Hall regime at ν=1\nu=1

    Visual attention modulates the into ration of goal-relevant evidence and not value

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    When choosing between options, such as food items presented in plain view, people tend to choose the option they spend longer looking at. The prevailing interpretation is that visual attention increases value. However, in previous studies, ‘value’ was coupled to a behavioural goal, since subjects had to choose the item they preferred. This makes it impossible to discern if visual attention has an effect on value, or, instead, if attention modulates the information most relevant for the goal of the decision-maker. Here, we present the results of two independent studies—a perceptual and a value-based task—that allow us to decouple value from goal-relevant information using specific task-framing. Combining psychophysics with computational modelling, we show that, contrary to the current interpretation, attention does not boost value, but instead it modulates goal-relevant information. This work provides a novel and more general mechanism by which attention interacts with choice

    Critical and Near-Critical Branching Processes

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    Scale-free dynamics in physical and biological systems can arise from a variety of causes. Here, we explore a branching process which leads to such dynamics. We find conditions for the appearance of power laws and study quantitatively what happens to these power laws when such conditions are violated. From a branching process model, we predict the behavior of two systems which seem to exhibit near scale-free behavior--rank-frequency distributions of number of subtaxa in biology, and abundance distributions of genotypes in an artificial life system. In the light of these, we discuss distributions of avalanche sizes in the Bak-Tang-Wiesenfeld sandpile model.Comment: 9 pages LaTex with 10 PS figures. v.1 of this paper contains results from non-critical sandpile simulations that were excised from the published versio

    Dynamic nuclear polarization at the edge of a two-dimensional electron gas

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    We have used gated GaAs/AlGaAs heterostructures to explore nonlinear transport between spin-resolved Landau level (LL) edge states over a submicron region of two-dimensional electron gas (2DEG). The current I flowing from one edge state to the other as a function of the voltage V between them shows diode-like behavior---a rapid increase in I above a well-defined threshold V_t under forward bias, and a slower increase in I under reverse bias. In these measurements, a pronounced influence of a current-induced nuclear spin polarization on the spin splitting is observed, and supported by a series of NMR experiments. We conclude that the hyperfine interaction plays an important role in determining the electronic properties at the edge of a 2DEG.Comment: 8 pages RevTeX, 7 figures (GIF); submitted to Phys. Rev.

    Millikelvin de Haas-van Alphen and magnetotransport studies of graphite

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    Copyright © 2011 American Physical SocietyRecent studies of the electronic properties of graphite have produced conflicting results regarding the positions of the different carrier types within the Brillouin zone, and the possible presence of Dirac fermions. In this paper we report a comprehensive study of the de Haas–van Alphen, Shubnikov–de Haas, and Hall effects in a sample of highly orientated pyrolytic graphite, at temperatures in the range 30 mK to 4 K and magnetic fields up to 12 T. The transport measurements confirm the Brillouin-zone locations of the different carrier types assigned by Schroeder, Dresselhaus and Javan Phys. Rev. Lett. 20 1292 (1968): electrons are at the K point, and holes are near the H points. We extract the cyclotron masses and scattering times for both carrier types from the temperature- and magnetic-field-dependences of the magneto-oscillations. Our results indicate that the holes experience stronger scattering and hence have lower mobility than the electrons. We utilize phase-frequency analysis and intercept analysis of the 1/B positions of magneto-oscillation extrema to identify the nature of the carriers in graphite, whether they are Dirac or normal (Schrödinger) fermions. These analyses indicate normal holes and electrons of indeterminate natur

    Evidence of Josephson-coupled superconducting regions at the interfaces of Highly Oriented Pyrolytic Graphite

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    Transport properties of a few hundreds of nanometers thick (in the graphene plane direction) lamellae of highly oriented pyrolytic graphite (HOPG) have been investigated. Current-Voltage characteristics as well as the temperature dependence of the voltage at different fixed input currents provide evidence for Josephson-coupled superconducting regions embedded in the internal two-dimensional interfaces, reaching zero resistance at low enough temperatures. The overall behavior indicates the existence of superconducting regions with critical temperatures above 100 K at the internal interfaces of oriented pyrolytic graphite.Comment: 6 Figures, 5 page

    Simple model for 1/f noise

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    We present a simple stochastic mechanism which generates pulse trains exhibiting a power law distribution of the pulse intervals and a 1/fα1/f^\alpha power spectrum over several decades at low frequencies with α\alpha close to one. The essential ingredient of our model is a fluctuating threshold which performs a Brownian motion. Whenever an increasing potential V(t)V(t) hits the threshold, V(t)V(t) is reset to the origin and a pulse is emitted. We show that if V(t)V(t) increases linearly in time, the pulse intervals can be approximated by a random walk with multiplicative noise. Our model agrees with recent experiments in neurobiology and explains the high interpulse interval variability and the occurrence of 1/fα1/f^\alpha noise observed in cortical neurons and earthquake data.Comment: 4 pages, 4 figure

    Data journalism beyond majority world countries:Challenges and opportunities

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    © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. This commentary reflects on the state of research on data journalism and discusses future directions for this line of work. Drawing on theory in international development and postcolonial studies, we discuss three critical pitfalls that we encourage future scholarship in this area to avoid. These include using a linear model of progress, in which journalists in Majority World nations struggle to ‘catch up’ to their Minority World counterparts because of the ‘obstacles’ they face; reproducing a simplistic split between the ‘West and the Rest’, thus missing the complex interaction of structures operating at different levels; and failing to examine journalistic agency due to an overemphasis on the technical structuring of the ‘tools’ used in data journalism. We also encourage scholars to engage in more comparative work rather than single case studies; increase dialogic communication between scholarship produced in, or about, different parts of the world; and incorporate more diverse methodologies with the aim of building theory. More broadly, we advocate for greater critical reflection upon—if not the challenging of—our dominant modes of thought in order to build more nuanced frameworks for explaining the complex causes, and potentially mixed effects, of data journalism around the world

    Universal Prefactor of Activated Conductivity in the Quantum Hall Effect

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    The prefactor of the activated dissipative conductivity in a plateau range of the quantum Hall effect is studied in the case of a long-range random potential. It is shown that due to long time it takes for an electron to drift along the perimeter of a large percolation cluster, phonons are able to maintain quasi-equilibrium inside the cluster. The saddle points separating such clusters may then be viewed as ballistic point contacts between electron reservoirs with different electrochemical potentials. The prefactor is universal and equal to 2e2/he^2/h at an integer filling factor ν\nu and to 2e2/q2he^2/q^{2}h at ν=p/q\nu=p/q.Comment: 4 pages + 2 figures by reques
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