42,202 research outputs found
The time course of routine action
Previous studies of action selection in routinized tasks have used error rates as their sole dependent measure (e.g. Reason, 1979; Schwartz et al., 1998). Consequently, conclusions about the underlying mechanisms of correct behavior are necessarily indirect. The present experiment examines the performance of normal subjects in the prototypical coffee task (Botvinick & Plaut, 2004) when carried out in a virtual environment on screen. This has the advantage of (a) constraining the possible errors more tightly than a real world environment, and (b) giving access to latencies as an additional, finer grained measure of performance. We report error data and timing of action selection at the crucial branching points for the production of routinized task sequences both with and without a secondary task. Processing branching points leads to increased latencies. The presence of the secondary task has a greater effect on latencies at branching points than at equivalent non-branching points. Furthermore, error data and latencies dissociate, suggesting that the exact timing is a valid and valuable source of information when trying to understand the processes that govern routine tasks. The results of the experiment are discussed in relation to their implication for computational accounts of routine action selection
The Power of Two Choices in Distributed Voting
Distributed voting is a fundamental topic in distributed computing. In pull
voting, in each step every vertex chooses a neighbour uniformly at random, and
adopts its opinion. The voting is completed when all vertices hold the same
opinion. On many graph classes including regular graphs, pull voting requires
expected steps to complete, even if initially there are only two
distinct opinions.
In this paper we consider a related process which we call two-sample voting:
every vertex chooses two random neighbours in each step. If the opinions of
these neighbours coincide, then the vertex revises its opinion according to the
chosen sample. Otherwise, it keeps its own opinion. We consider the performance
of this process in the case where two different opinions reside on vertices of
some (arbitrary) sets and , respectively. Here, is the
number of vertices of the graph.
We show that there is a constant such that if the initial imbalance
between the two opinions is ?, then with high probability two sample voting completes in a random
regular graph in steps and the initial majority opinion wins. We
also show the same performance for any regular graph, if where is the second largest eigenvalue of the transition
matrix. In the graphs we consider, standard pull voting requires
steps, and the minority can still win with probability .Comment: 22 page
Breakdown of counterflow superfluidity in a disordered quantum Hall bilayer
We present a theory for the regime of coherent interlayer tunneling in a
disordered quantum Hall bilayer at total filling factor one, allowing for the
effect of static vortices. We find that the system consists of domains of
polarized superfluid phase. Injected currents introduce phase slips between the
polarized domains which are pinned by disorder. We present a model of saturated
tunneling domains that predicts a critical current for the breakdown of
coherent tunneling that is extensive in the system size. This theory is
supported by numerical results from a disordered phase model in two dimensions.
We also discuss how our picture might be used to interpret experiments in the
counterflow geometry and in two-terminal measurements.Comment: 7 pages, 3 figure
Youth and the future: effective youth services for the year 2015
This report provides an understanding of the services required by young people in the year 2015, based on a thorough analysis of recent trends and expert projections of those trends. The report analyses key social and economic changes for young people in Australia over the past 10 to 20 years including movements in population, education, employment/unemployment and the labour market, incomes, family and household structure, health, and crime and justice
Observation of narrow-band noise accompanying the breakdown of insulating states in high Landau levels
Recent magnetotransport experiments on high mobility two-dimensional electron
systems have revealed many-body electron states unique to high Landau levels.
Among these are re-entrant integer quantum Hall states which undergo sharp
transitions to conduction above some threshold field. Here we report that these
transitions are often accompanied by narrow- and broad-band noise with
frequencies which are strongly dependent on the magnitude of the applied dc
current.Comment: 4 pages, 3 figure
Fragmentation pathways of [Re₂(μ-OR)₃(CO)₆]– (R = H, Me) and ligand exchange reactions with oxygen donor ligands, investigated by electrospray mass spectrometry
The rhenium hydroxy and methoxy carbonyl complexes [Re₂(μOR)₃(CO)₆]⁻ (R = H or Me) have been studied by negative-ion electrospray mass spectrometry (ESMS). The complexes undergo facile exchange reactions with protic compounds, including alcohols and phenols. With dimethyl malonate, ester hydrolysis occurs giving carboxylate-containing complexes, and with H₂O₂ or ButOOH, oxidation to ReO₄⁻occurs. The feasibility and extent of these reactions can conveniently, rapidly, and unambiguously be determined by electrospray mass spectrometry, and is dependent on the acidity and steric bulk of the protic compound. The results also suggest that the complexes can be used as versatile starting materials for the synthesis of a wide range of analogous [Re₂(μ-OR)₃(CO)₆]⁻ complexes by simple reaction with an excess of the appropriate alcohol. By varying the applied cone voltage the fragmentation pathways have been investigated; the hydroxy complex undergoes dehydration followed by CO loss, whereas for the methoxy complex -hydride elimination (and CO loss) is observed, with confirmation provided by deuterium labelling studies. Under ESMS conditions, the neutral complexes [Re₂(μ-OR)₂(μ-dppf )(CO)₆] [R = H or Me; dppf = 1,1 -bis(diphenylphosphino)ferrocene] undergo substantial solvolysis and hydrolysis to give mainly mononuclear species; simple parent ions (e.g. [M + H]⁺) are not formed in appreciable abundance, probably due to the lack of an efficient ionisation pathway
GNurseSIM intercultural simulation for caring for elderly patients: Reflections on co-creation of artefacts
This case study presents the experiences and perceptions of nursing lecturers and students jointly co-creating video simulation artefacts for an Intercultural Care for Elderly Patients.
Context
Globally, the number of elderly over the age of 80 is expected to triple by 2050 up to 426 million. Complexities with cultural perceptions of disorders or healthy ageing impact on access to and appropriate care or health promotion. Global movements mean it is likely diverse elderly patients will encounter as culturally diverse nurses and carers with varied perceptions of elderly and careneeds. Simulation can supplement situated learning to explore complex topics such as intercultural care. An EU funded project: GNurseSIM European consortium (7 partners across 5 countries) was the driver of developing simulations.
Method
This UK case study resulted from student reflections, piloting and evaluation and learning from the co-creation approach and scenarios.
Results
Reflective narratives reveal an awareness of the breadth of culture expression, fallibility of assumptions, self-development and being a ‘professional’ that translate into practice.
Conclusion
The experience of partnership in building these simulation videos point to a deep and transformative learning experience through student co-creation. This approach offers means to develop professional attributes otherwise challenging to teach
Metastable Resistance Anisotropy Orientation of Two-Dimensional Electrons in High Landau Levels
In half-filled high Landau levels, two-dimensional electron systems possess
collective phases which exhibit a strongly anisotropic resistivity tensor. A
weak, but as yet unknown, rotational symmetry-breaking potential native to the
host semiconductor structure is necessary to orient these phases in macroscopic
samples. Making use of the known external symmetry-breaking effect of an
in-plane magnetic field, we find that the native potential can have two
orthogonal local minima. It is possible to initialize the system in the higher
minimum and then observe its relaxation toward equilibrium.Comment: 5 pages, 3 figures. Figure references corrected. Version accepted for
publication in Physical Review Letter
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