10,627 research outputs found

    The behavioural impact of a visually represented virtual assistant in a selfservice checkout context

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    Our research investigated whether the presence of an interface agent - or virtual assistant (VA) - in a self-service checkout context has behavioural effects on the transaction process during particular tasks. While many participants claimed to have not noticed a VA within the self-service interface, behaviour was still affected, i.e. fewer people made errors with the VA present than in the voice-only and control conditions. The results are explained as reflective of an unconscious observation of non-verbal cues exhibited by the VA. The results are discussed in relation to possible behavioural outcomes of VA presence.</p

    Nuclear Corrections to Hyperfine Structure in Light Hydrogenic Atoms

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    Hyperfine intervals in light hydrogenic atoms and ions are among the most accurately measured quantities in physics. The theory of QED corrections has recently advanced to the point that uncalculated terms for hydrogenic atoms and ions are probably smaller than 0.1 parts per million (ppm), and the experiments are even more accurate. The difference of the experiments and QED theory is interpreted as the effect on the hyperfine interaction of the (finite) nuclear charge and magnetization distributions, and this difference varies from tens to hundreds of ppm. We have calculated the dominant component of the 1s hyperfine interval for deuterium, tritium and singly ionized helium, using modern second-generation potentials to compute the nuclear component of the hyperfine splitting for the deuteron and the trinucleon systems. The calculated nuclear corrections are within 3% of the experimental values for deuterium and tritium, but are about 20% discrepant for singly ionized helium. The nuclear corrections for the trinucleon systems can be qualitatively understood by invoking SU(4) symmetry.Comment: 26 pages, 1 figure, latex - submitted to Physical Review

    Frequency spectrum of gravitational radiation from global hydromagnetic oscillations of a magnetically confined mountain on an accreting neutron star

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    Recent time-dependent, ideal-magnetohydrodynamic (ideal-MHD) simulations of polar magnetic burial in accreting neutron stars have demonstrated that stable, magnetically confined mountains form at the magnetic poles, emitting gravitational waves at f∗f_{*} (stellar spin frequency) and 2f∗2 f_{*}. Global MHD oscillations of the mountain, whether natural or stochastically driven, act to modulate the gravitational wave signal, creating broad sidebands (full-width half-maximum ∼0.2f∗\sim 0.2f_*) in the frequency spectrum around f∗f_{*} and 2f∗2 f_{*}. The oscillations can enhance the signal-to-noise ratio achieved by a long-baseline interferometer with coherent matched filtering by up to 15 per cent, depending on where f∗f_* lies relative to the noise curve minimum. Coherent, multi-detector searches for continuous waves from nonaxisymmetric pulsars should be tailored accordingly.Comment: 4 figures, accepted for publication in Ap

    Virtual assistants and social cues:retail interactions and consumer experience

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    This paper describes a multi-disciplinary approach toinforming the design of a Virtual Assistant (VA) for use ina self-service checkout (SSCO). SSCO transactions requirehigh levels of attention as people attempt to performmultiple tasks in the shortest possible time. This is ofteneffortful, affecting performance and satisfaction. One proposed solution is a VA to help guide users’ attention torelevant areas. This paper discusses three key positiveoutcomes to cueing attention with a VA. It also highlightsthe advantage of adopting a multi-disciplinary perspectiveto providing solutions to business problems in a modernretail context

    Multifrequency Radio Observations of a SNR in the LMC. The Case of SNR J0527-6549 (DEM l204)

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    We present a detailed study and results of new Australia Telescope Compact Array (ATCA) observations of supernova remnant, SNR J0527-6549. This Large Magellanic Cloud (LMC) ob ject follows a typical supernova remnant (SNR) horseshoe morphology with a diameter of D=(66x58)+-1 pc which is among the largest SNRs in the LMC. Its relatively large size indicates older age while a steeper than expected radio spectral index of aplha=-0.92+-0.11 is more typical for younger and energetic SNRs. Also, we report detections of regions with a high order of polarization at a peak value of ~54+-17% at 6 cm.Comment: 9 Pages, 6 figures, accepted for publication in SA

    High-concentration Er:YAG single-crystal fibers grown by laser-heated pedestal growth technique

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    High-concentration Er:YAG single-crystal fibers have been grown using the laser-heated pedestal growth technique. Instability in the melt and concomitant opacity of fibers were observed at source concentrations higher than 15 mol.%. Spectroscopic examination shows that broadening of the linewidth of the I&lt;sub&gt;13/2&lt;/sub&gt;4→I&lt;sub&gt;15/2&lt;/sub&gt;4 transition is strongly dependent on Er&lt;sup&gt;3+&lt;/sup&gt; concentration

    Spectacular recovery in the Ord River catchment

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    Regeneration work on severely damaged country in what is now known as the Ord River Regeneration Reserve (ORRR) commenced in 1960. The ORRR is in the East Kimberley area of Western Australia with an associated small area in the Northern Territory. The work included strip contour cultivation and seeding (which proceeded at various levels of intensity during the 1960s, 1970s and 1980s), fencing and destocking of cattle by mustering over many years, and the eradication of donkeys

    Magnetic structure of free cobalt clusters studied with Stern-Gerlach deflection experiments

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    We have studied the magnetic properties of free cobalt clusters in two semi-independent Stern-Gerlach deflection experiments at temperatures between 60 and 307 K. We find that clusters consisting of 13 to 200 cobalt atoms exhibit behavior that is entirely consistent with superparamagnetism, though complicated by finite-system fluctuations in cluster temperature. By fitting the data to the Langevin function, we report magnetic moments per atom for each cobalt cluster size and compare the results of our two measurements and all those performed previously. In addition to a gradual decrease in moment per atom with increasing size, there are oscillations that appear to be caused by geometrical shell structure. We discuss our observations in light of the two competing models for Langevin-like magnetization behavior in free clusters, superparamagnetism and adiabatic magnetization, and conclude that the evidence strongly supports the superparamagnetic model

    Supercell technique for total-energy calculations of finite charged and polar systems

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    We study the behavior of total-energy supercell calculations for dipolar molecules and charged clusters. Using a cutoff Coulomb interaction within the framework of a plane-wave basis set formalism, with all other aspects of the method (pseudopotentials, basis set, exchange-correlation functional) unchanged, we are able to assess directly the interaction effects present in the supercell technique. We find that the supercell method gives structures and energies in almost total agreement with the results of calculations for finite systems, even for molecules with large dipole moments. We also show that the performance of finite-grid calculations can be improved by allowing a degree of aliasing in the Hartree energy, and by using a reciprocal space definition of the cutoff Coulomb interaction

    Water Chemisorption and Reconstruction of the MgO Surface

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    The observed reactivity of MgO with water is in apparent conflict with theoretical calculations which show that molecular dissociation does not occur on a perfect (001) surface. We have performed ab-initio total energy calculations which show that a chemisorption reaction involving a reconstruction to form a (111) hydroxyl surface is strongly preferred with Delta E = -90.2kJ/mol. We conclude that protonation stabilizes the otherwise unstable (111) surface and that this, not the bare (001), is the most stable surface of MgO under ambient conditions.Comment: RevTeX, 4 pages, 1 Encapsulated Postscript Figur
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