29,430 research outputs found

    Peripheral visual response time to colored stimuli imaged on the horizontal meridian

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    Two male observers were administered a binocular visual response time task to small (45 min arc), flashed, photopic stimuli at four dominant wavelengths (632 nm red; 583 nm yellow; 526 nm green; 464 nm blue) imaged across the horizontal retinal meridian. The stimuli were imaged at 10 deg arc intervals from 80 deg left to 90 deg right of fixation. Testing followed either prior light adaptation or prior dark adaptation. Results indicated that mean response time (RT) varies with stimulus color. RT is faster to yellow than to blue and green and slowest to red. In general, mean RT was found to increase from fovea to periphery for all four colors, with the curve for red stimuli exhibiting the most rapid positive acceleration with increasing angular eccentricity from the fovea. The shape of the RT distribution across the retina was also found to depend upon the state of light or dark adaptation. The findings are related to previous RT research and are discussed in terms of optimizing the color and position of colored displays on instrument panels

    Secondary teachers' perceptions of the effectiveness of their pre-service education and strategies to improve pre-service education for teachers: A school based training route in England

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    This study aims to provide a deeper understanding of the impact of an EBITT course on teachers' early professional development, identify strengths of the course and also the ways in which the training could be improved. Data collected was recorded during individual face- to- face interviews using a structured interview schedule. In devising our approach we utilised the model suggested by Sharon Feiman-Nemser in her article How do Teachers Learn to Teach? in Cochran - Smith et. al. (2008) Handbook of Research on Teacher Education The data was analysed to explore (after 2-4 years reflection): • which elements of initial training were valuable and less valuable • what they have learned since the course • which aspects of the course the teachers feel should be improved It was cross referenced against findings from national surveys of teachers in their post qualifying year of teaching (induction year) and early years of teaching conducted by the TDA. These findings were presented as part of a common wider international study on the same theme in four countries (UK, Spain, Australia, and Ireland)

    Reliability considerations in the design, assembly, and testing of the mariner iv power system

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    Reliability considerations in design, assembly, and testing of Mariner IV power syste

    HI Absorption Toward HII Regions at Small Galactic Longitudes

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    We make a comprehensive study of HI absorption toward HII regions located within Galactic longitudes less than 10 degrees. Structures in the extreme inner Galaxy are traced using the longitude-velocity space distribution of this absorption. We find significant HI absorption associated with the Near and Far 3kpc Arms, the Connecting Arm, Banias Clump 1 and the H I Tilted Disk. We also constrain the line of sight distances to HII regions, by using HI absorption spectra together with the HII region velocities measured by radio recombination lines.Comment: Complete figure set available in online version of journal. Accepted by ApJ August 8, 201

    Fault-tolerant quantum computation with cluster states

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    The one-way quantum computing model introduced by Raussendorf and Briegel [Phys. Rev. Lett. 86 (22), 5188-5191 (2001)] shows that it is possible to quantum compute using only a fixed entangled resource known as a cluster state, and adaptive single-qubit measurements. This model is the basis for several practical proposals for quantum computation, including a promising proposal for optical quantum computation based on cluster states [M. A. Nielsen, arXiv:quant-ph/0402005, accepted to appear in Phys. Rev. Lett.]. A significant open question is whether such proposals are scalable in the presence of physically realistic noise. In this paper we prove two threshold theorems which show that scalable fault-tolerant quantum computation may be achieved in implementations based on cluster states, provided the noise in the implementations is below some constant threshold value. Our first threshold theorem applies to a class of implementations in which entangling gates are applied deterministically, but with a small amount of noise. We expect this threshold to be applicable in a wide variety of physical systems. Our second threshold theorem is specifically adapted to proposals such as the optical cluster-state proposal, in which non-deterministic entangling gates are used. A critical technical component of our proofs is two powerful theorems which relate the properties of noisy unitary operations restricted to act on a subspace of state space to extensions of those operations acting on the entire state space.Comment: 31 pages, 54 figure

    Fault-tolerant quantum computation with high threshold in two dimensions

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    We present a scheme of fault-tolerant quantum computation for a local architecture in two spatial dimensions. The error threshold is 0.75% for each source in an error model with preparation, gate, storage and measurement errors.Comment: 4 pages, 4 figures; v2: A single 2D layer of qubits (simple square lattice) with nearest-neighbor translation-invariant Ising interaction suffices. Slightly improved threshol
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