1,072 research outputs found

    Satisfaction with Cognitive Rehabilitation Delivered via the Internet in Persons with Acquired Brain Injury

    Get PDF
    We examined the level of satisfaction with cognitive rehabilitation delivered via the Internet in persons with moderate to severe acquired brain injury (ABI). Fifteen adults with moderate to severe ABI were randomized to 30 days of Internet-based active treatment (AT) or to a wait list (WL) group, and crossed over to the opposite condition after 30 sessions. Both caregivers and participants were assessed at three time points during the study. This study focused on participant satisfaction with receiving treatment in this manner. Though the results of this study showed no significant treatment effect, the vast majority of participants (>87%) were satisfied with treatment. Treatment satisfaction accounted for 25% of additional variance in predicting lower family ratings of mood difficulties after final assessment (p<.03). Greater satisfaction with treatment was positively correlated with greater employment rate after treatment (r=.63, p=.02), as well as lower family ratings of memory and mood difficulties after final assessment (r=-.59, p=.03; r=-.58, p=.03,). Results suggest that treatment satisfaction in persons with ABI is related to less activity limitations, and maintaining employment after cognitive rehabilitation delivered via the Internet. 

    Patterns of Coastal Land Cover and Estuarine Habitat Quality: Application of Long-term Monitoring Data

    Get PDF
    2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio

    Structural materials from recycled high density polyethylene and herbaceous fibers, and method for production

    Get PDF
    A composite useful for structural components comprised of recycled high density polyethylene and herbaceous fibrous materials and a method to produce composites based on recycled high density polyethylene and chopped herbaceous fibers. An alternative structural composite is disclosed which is comprised of recycled low density polyethylene and chopped herbaceous fibrous material

    Quantum state engineering on an optical transition and decoherence in a Paul trap

    Get PDF
    A single Ca+ ion in a Paul trap has been cooled to the ground state of vibration with up to 99.9% probability. Starting from this Fock state |n=0> we have demonstrated coherent quantum state manipulation on an optical transition. Up to 30 Rabi oscillations within 1.4 ms have been observed. We find a similar number of Rabi oscillations after preparation of the ion in the |n=1> Fock state. The coherence of optical state manipulation is only limited by laser and ambient magnetic field fluctuations. Motional heating has been measured to be as low as one vibrational quantum in 190 ms.Comment: 4 pages, 5 figure

    Speed of ion trap quantum information processors

    Get PDF
    We investigate theoretically the speed limit of quantum gate operations for ion trap quantum information processors. The proposed methods use laser pulses for quantum gates which entangle the electronic and vibrational degrees of freedom of the trapped ions. Two of these methods are studied in detail and for both of them the speed is limited by a combination of the recoil frequency of the relevant electronic transition, and the vibrational frequency in the trap. We have experimentally studied the gate operations below and above this speed limit. In the latter case, the fidelity is reduced, in agreement with our theoretical findings. // Changes: a) error in equ. 24 and table III repaired b) reference Jonathan et al, quant-ph/ 0002092, added (proposes fast quantum gates using the AC-Stark effect)Comment: 10 pages, 4 figure

    Absolute Frequency Measurements of the Hg^+ and Ca Optical Clock Transitions with a Femtosecond Laser

    Get PDF
    The frequency comb created by a femtosecond mode-locked laser and a microstructured fiber is used to phase coherently measure the frequencies of both the Hg^+ and Ca optical standards with respect to the SI second as realized at NIST. We find the transition frequencies to be f_Hg=1 064 721 609 899 143(10) Hz and f_Ca=455 986 240 494 158(26) Hz, respectively. In addition to the unprecedented precision demonstrated here, this work is the precursor to all-optical atomic clocks based on the Hg^+ and Ca standards. Furthermore, when combined with previous measurements, we find no time variations of these atomic frequencies within the uncertainties of |(df_Ca/dt)/f_Ca| < 8 x 10^{-14} yr^{-1}, and |(df_Hg/dt)/f_Hg|< 30 x 10^{-14} yr^{-1}.Comment: 6 pages, including 4 figures. RevTex 4. Submitted to Phys. Rev. Let

    Motional sidebands and direct measurement of the cooling rate in the resonance fluorescence of a single trapped ion

    Full text link
    Resonance fluorescence of a single trapped ion is spectrally analyzed using a heterodyne technique. Motional sidebands due to the oscillation of the ion in the harmonic trap potential are observed in the fluorescence spectrum. From the width of the sidebands the cooling rate is obtained and found to be in agreement with the theoretical prediction.Comment: 4 pages, 4 figures. Final version after minor changes, 1 figure replaced; to be published in PRL, July 10, 200

    Trapped ions in the strong excitation regime: ion interferometry and non--classical states

    Get PDF
    The interaction of a trapped ion with a laser beam in the strong excitation regime is analyzed. In this regime, a variety of non--classical states of motion can be prepared either by using laser pulses of well defined area, or by an adiabatic passage scheme based on the variation of the laser frequency. We show how these states can be used to investigate fundamental properties of quantum mechanics. We also study possible applications of this system to build an ion interferometer.Comment: 9 pages, Revtex format, 5 compressed postscript figure
    • …
    corecore