1,048 research outputs found

    COGNITIVE CRUISE CONTROL: INVESTIGATING HOW CONTEXT AFFECTS THE MOMENTUM OF COGNITIVE CONTROL

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    In the present studies a coordination dynamics perspective is taken to explore the interplay of perception and action in a continuous dual-task paradigm. Two experiments will be conducted using an action-dynamics methodology, through tracking response trajectories with the Nintendo Wii remote, which allows for analysis of how a response unfolds over time. The real-time data (i.e., the response trajectories) are expected to reflect an intriguing pattern of cognitive competition as attention adapts to trial context. The purpose of this work is twofold: a) exploring whether attention/cognitive control is best characterized in terms of its structural limitations (i.e., bottleneck) or its flexible, dynamic properties and, b) investigate if any patterns emerge in the response trajectories that may be indicative of the cognitive system adjusting to conform to the unique combination of experimental parameters

    Enlivening the Rhetoric of Family Nursing: "there, in the midst of things, his whole family listening"

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    At the time that this study was conducted, family nursing practice in acute care hospital settings had received little attention in nursing research and theory. A hermeneutic inquiry explored nursing practices that involved families on three cardiac medical-surgical units in two hospitals in a large urban health care region in Canada. Data for the inquiry were generated through field observations with fifteen nurses and interviews with ten nurses. Nurses supported and enabled family presence in these units but demonstrated limited evidence of deliberate family assessment and intervention. Nurses espoused a familiar rhetoric that claimed that family nursing exists because of the inevitability of encounters with family members throughout daily work. Nurses wished to appear to include family members in their practice and emphasized the importance of family teaching. Still, nurses’ ability to articulate the nature of this practice was limited. Family nursing rhetoric is explored as a potentially legitimate discourse that underlies current trends influencing nursing of families, particularly the impact of early discharge and increased reliance on family members to provide care at home during early recovery

    Intensive Care Unit Nursing: An Interpretable and Hermeneutic Practice

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    Intensive care unit (ICU) nursing is an interpretive practice. Hermeneutics, as an interpretive philosophy, is an ideal approach to make meaning of the ambiguities that exist in this intensive practice setting. This paper uses the underpinnings from Gadamer’s philosophical hermeneutics to explore the idea that ICU nursing is an interpretive practice.

    Pressure shift of the superconducting T_c of LiFeAs

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    The effect of hydrostatic pressure on the superconductivity in LiFeAs is investigated up to 1.8 GPa. The superconducting transition temperature, T_c, decreases linearly with pressure at a rate of 1.5 K/GPa. The negative pressure coefficient of T_c and the high ambient pressure T_c indicate that LiFeAs is the high-pressure analogue of the isoelectronic SrFe_2As_2 and BaFe_2As_2.Comment: 3 pages, 2 figure

    The Synthesis and Characterization of LiFeAs and NaFeAs

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    The newest homologous series of superconducting As-pnictides, LiFeAs (Li111) and NaFeAs (Na111) have been synthesized and investigated. Both crystallize with the layered tetragonal anti-PbFCl-type structure in P4/nmm space group. Polycrystalline samples and single-crystals of Li111 and Na111 display superconducting transitions at ~ 18 K and 12-25 K, respectively. No magnetic order has been found in either compound, although a weak magnetic background is clearly in evidence. The origin of the carriers and the stoichiometric compositions of Li111 and Na111 were explored.Comment: submitted for publication in Physica C special issue on Fe-pnictide

    Optimality of private quantum channels

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    We addressed the question of optimality of private quantum channels. We have shown that the Shannon entropy of the classical key necessary to securely transfer the quantum information is lower bounded by the entropy exchange of the private quantum channel E\cal E and von Neumann entropy of the ciphertext state ϱ(0)\varrho^{(0)}. Based on these bounds we have shown that decomposition of private quantum channels into orthogonal unitaries (if exists) is optimizing the entropy. For non-ancillary single qubit PQC we have derived the optimal entropy for arbitrary set of plaintexts. In particular, we have shown that except when the (closure of the) set of plaintexts contains all states, one bit key is sufficient. We characterized and analyzed all the possible single qubit private quantum channels for arbitrary set of plaintexts. For the set of plaintexts consisting of all qubit states we have characterized all possible approximate private quantum channels and we have derived the relation between the security parameter and the corresponding minimal entropy.Comment: no commen

    First-Principles Study for the Anisotropy of Iron-based Superconductors toward Power and Device Applications

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    Performing the first-principles calculations, we investigate the anisotropy in the superconducting state of iron-based superconductors to gain an insight into their potential applications. The anisotropy ratio γλ\gamma_\lambda of the c-axis penetration depth to the ab-plane one is relatively small in BaFe2As2 and LiFeAs, i.e., γλ∼3\gamma_\lambda \sim 3, indicating that the transport applications are promising in these superconductors. On the other hand, in those having perovskite type blocking layers such as Sr2ScFePO3 we find a very large value, γλ∼200\gamma_\lambda \sim 200, comparable to that in strongly anisotropic high-Tc cuprate Bi2Sr2CaCu2O{8-\delta}. Thus, the intrinsic Josephson junction stacks are expected to be formed along the c-axis, and novel Josephson effects due to the multi-gap nature are also suggested in these superconductors.Comment: 5 pages, 4 figure

    Crossover from commensurate to incommensurate antiferromagnetism in stoichiometric NaFeAs revealed by single-crystal 23Na,75As-NMR experiments

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    We report results of 23Na and 75As nuclear magnetic resonance (NMR) experiments on a self-flux grown high-quality single crystal of stoichiometric NaFeAs. The NMR spectra revealed a tetragonal to twinned-orthorhombic structural phase transition at T_O = 57 K and an antiferromagnetic (AF) transition at T_AF = 45 K. The divergent behavior of nuclear relaxation rate near T_AF shows significant anisotropy, indicating that the critical slowing down of stripe-type AF fluctuations are strongly anisotropic in spin space. The NMR spectra at low enough temperatures consist of sharp peaks showing a commensurate stripe AF order with a small moment \sim 0.3 muB. However, the spectra just below T_AF exhibits highly asymmetric broadening pointing to an incommensurate modulation. The commensurate-incommensurate crossover in NaFeAs shows a certain similarity to the behavior of SrFe2As2 under high pressure.Comment: 5 pages, 5 figures, revised version to appear in J. Phys. Soc. Jp
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