2,095 research outputs found

    An Analysis of Kinetic Response Variability

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    Studies evaluating variability of force as a function of absolute force generated are synthesized. Inconsistencies in reported estimates of this relationship are viewed as a function of experimental constraints imposed. Typically, within-subject force variability increases at a negative accelerating rate with equal increments in force produced. Current pulse-step and impulse variability models are unable to accommodate this description, although the notion of efficiency is suggested as a useful construct to explain the description outlined

    Community Restoration: A snapshot on how it is obtained and what are the effects?

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    Community Restoration: A snapshot on how it is obtained and what are the effects? The presentation examines some of the factors to a successful community restoration and what are the end results of a restored community especially when we participate in the process

    Land Cover Data for the Mississippi-Alabama Barrier Islands, 2010-2011

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    Land cover on the Mississippiā€“Alabama barrier islands was surveyed in 2010ā€“2011 as part of continuing research on island geomorphic and vegetation dynamics following the 2005 impact of Hurricane Katrina. Results of the survey include sub-meter GPS location, a listing of dominant vegetation species and field photographs recorded at 375 sampling locations distributed among Cat, West Ship, East Ship, Horn, Sand, Petit Bois and Dauphin Islands. The survey was conducted in a period of intensive remote sensing data acquisition over the northern Gulf of Mexico by federal, state and commercial organizations in response to the 2010 Macondo Well (Deepwater Horizon) oil spill. The data are useful in providing ground reference information for thematic classification of remotely-sensed imagery, and a record of land cover which may be used in future research

    Coherent Quantum-Noise Cancellation for Optomechanical Sensors

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    Using a flowchart representation of quantum optomechanical dynamics, we design coherent quantum-noise-cancellation schemes that can eliminate the back-action noise induced by radiation pressure at all frequencies and thus overcome the standard quantum limit of force sensing. The proposed schemes can be regarded as novel examples of coherent feedforward quantum control.Comment: 4 pages, 5 figures, v2: accepted by Physical Review Letter

    Driving Toward a Culture of ā€œZero CAUTIsā€

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    Qubit metrology and decoherence

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    Quantum properties of the probes used to estimate a classical parameter can be used to attain accuracies that beat the standard quantum limit. When qubits are used to construct a quantum probe, it is known that initializing nn qubits in an entangled "cat state," rather than in a separable state, can improve the measurement uncertainty by a factor of 1/n1/\sqrt{n}. We investigate how the measurement uncertainty is affected when the individual qubits in a probe are subjected to decoherence. In the face of such decoherence, we regard the rate RR at which qubits can be generated and the total duration Ļ„\tau of a measurement as fixed resources, and we determine the optimal use of entanglement among the qubits and the resulting optimal measurement uncertainty as functions of RR and Ļ„\tau.Comment: 24 Pages, 3 Figure

    Direct neutron capture of 48Ca at kT = 52 keV

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    The neutron capture cross section of 48Ca was measured relative to the known gold cross section at kT = 52 keV using the fast cyclic activation technique. The experiment was performed at the Van-de-Graaff accelerator, Universitaet Tuebingen. The new experimental result is in good agreement with a calculation using the direct capture model. The 1/v behaviour of the capture cross section at thermonuclear energies is confirmed, and the adopted reaction rate which is based on several previous experimental investigations remains unchanged.Comment: 9 pages (uses Revtex), 2 postscript figures, accepted for publication as Brief Report in Phys. Rev.

    Reversible quantum operations and their application to teleportation

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    Quantum operations provide a general description of the state changes allowed by quantum mechanics. Simple necessary and sufficient conditions for an ideal quantum operation to be reversible by a unitary operation are derived in this paper. These results generalize recent work on reversible measurements by Mabuchi and Zoller [Phys. Rev. Lett. {\bf 76}, 3108 (1996)]. Quantum teleportation can be understood as a special case of the problem of reversing quantum operations. We characterize completely teleportation schemes of the type proposed by Bennett {\it et al.} [Phys. Rev. Lett. {\bf 70}, 1895 (1993)].Comment: 10 pages, Revte
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