131 research outputs found

    Social and Behavioral Domains in Acute Care Electronic Health Records: Barriers, Facilitators, Relevance, and Value.

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    Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018

    Porous Superhydrophobic Membranes: Hydrodynamic Anomaly in Oscillating Flows

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    We have fabricated and characterized a novel superhydrophobic system, a mesh-like porous superhydrophobic membrane with solid area fraction Φs\Phi_s, which can maintain intimate contact with outside air and water reservoirs simultaneously. Oscillatory hydrodynamic measurements on porous superhydrophobic membranes as a function of Φs\Phi_s reveal surprising effects. The hydrodynamic mass oscillating in-phase with the membranes stays constant for 0.9Φs10.9\le\Phi_s\le1, but drops precipitously for Φs<0.9\Phi_s < 0.9. The viscous friction shows a similar drop after a slow initial decrease proportional to Φs\Phi_s. We attribute these effects to the percolation of a stable Knudsen layer of air at the interface.Comment: 5 pages, 3 figure

    Gerasimov-Drell-Hearn Sum Rule and the Discrepancy between the New CLAS and SAPHIR Data

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    Contribution of the K^+\Lambda channel to the Gerasimov-Drell-Hearn (GDH) sum rule has been calculated by using the models that fit the recent SAPHIR or CLAS differential cross section data. It is shown that the two data sets yield quite different contributions. Contribution of this channel to the forward spin polarizability of the proton has been also calculated. It is also shown that the inclusion of the recent CLAS C_x and C_z data in the fitting data base does not significantly change the result of the present calculation. Results of the fit, however, reveal the role of the S_{11}(1650), P_{11}(1710), P_{13}(1720), and P_{13}(1900) resonances for the description of the C_x and C_z data. A brief discussion on the importance of these resonances is given. Measurements of the polarized total cross section \sigma_{TT'} by the CLAS, LEPS, and MAMI collaborations are expected to verify this finding.Comment: 15 pages, 8 figure

    Coherent Control of Atomic Beam Diffraction by Standing Light

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    Quantum interference is shown to deliver a means of regulating the diffraction pattern of a thermal atomic beam interacting with two standing wave electric fields. Parameters have been identified to enhance the diffraction probability of one momentum component over the others, with specific application to Rb atoms.Comment: 5 figure

    Scaling laws in velocity-selective coherent population trapping in the presence of polarization-gradient cooling

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    One-dimensional laser cooling based on velocity-selective coherent population trapping (VSCPT) on a 2g→1e transition has been investigated numerically through the solution of the optical Bloch equations. As in the work of G. Morigi et al. [Phys. Rev. A 53, 2616 (1996)], it has been found that for a large set of atomic and laser parameters, the VSCPT cooling process may be described through scaling-law relations. The scaling laws are based on the relations between the loss rates at large atomic momentum and their dependence on the momentum around zero value. The role of the laser detuning on the VSCPT trapping efficiency has been examined and scaling laws including the detuning have been derived

    Atom-optics hologram in the time domain

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    The temporal evolution of an atomic wave packet interacting with object and reference electromagnetic waves is investigated beyond the weak perturbation of the initial state. It is shown that the diffraction of an ultracold atomic beam by the inhomogeneous laser field can be interpreted as if the beam passes through a three-dimensional hologram, whose thickness is proportional to the interaction time. It is found that the diffraction efficiency of such a hologram may reach 100% and is determined by the duration of laser pulses. On this basis a method for reconstruction of the object image with matter waves is offered.Comment: RevTeX, 13 pages, 8 figures; minor grammatical change

    Quantum-state control in optical lattices

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    We study the means to prepare and coherently manipulate atomic wave packets in optical lattices, with particular emphasis on alkali atoms in the far-detuned limit. We derive a general, basis independent expression for the lattice operator, and show that its off-diagonal elements can be tailored to couple the vibrational manifolds of separate magnetic sublevels. Using these couplings one can evolve the state of a trapped atom in a quantum coherent fashion, and prepare pure quantum states by resolved-sideband Raman cooling. We explore the use of atoms bound in optical lattices to study quantum tunneling and the generation of macroscopic superposition states in a double-well potential. Far-off-resonance optical potentials lend themselves particularly well to reservoir engineering via well controlled fluctuations in the potential, making the atom/lattice system attractive for the study of decoherence and the connection between classical and quantum physics.Comment: 35 pages including 8 figures. To appear in Phys. Rev. A. March 199
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