1,982 research outputs found

    Sublingual Emphysema Following Alveoloplasty: A Case Report

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    Various cases of introduction of air into soft tissues have been reported in the dental literature. Here, we report a rare case of localized sublingual emphysema after alveoloplasty. There was no facial involvement. The patient responded to treatment and recovered uneventfully

    A 200 Year Record of Carbon-13 and Carbon-14 Variations in a Bermuda Coral

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    A 200 year old brain coral, captured in Bermuda in 1976 was slabbed and x-rayed. Using the annual growth bands sequential, dated samples were taken over the entire growth period of the coral and analyzed for Δ14C, δ13C and δ18O. During the past 80 years atmospheric variations in Δ14C and δ13C due to human effects, such as release of bomb C-14 and dilution of both C-14 and C-13 by fossil fuel burning, are closely tracked by the coral. Prior to 1900 divergences between the coral and tree Δ14C and δ13C can be related to world-wide changes in plant production and possibly oceanic upwelling rates

    Designing multiplayer games to facilitate emergent social behaviours online

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    This paper discusses an exploratory case study of the design of games that facilitate spontaneous social interaction and group behaviours among distributed individuals, based largely on symbolic presence 'state' changes. We present the principles guiding the design of our game environment: presence as a symbolic phenomenon, the importance of good visualization and the potential for spontaneous self-organization among groups of people. Our game environment, comprising a family of multiplayer 'bumper-car' style games, is described, followed by a discussion of lessons learned from observing users of the environment. Finally, we reconsider and extend our design principles in light of our observations

    Deviations from Matthiessen's Rule for SrRuO3{\rm SrRuO_3} and CaRuO3{\rm CaRuO_3}

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    We have measured the change in the resistivity of thin films of SrRuO3{\rm SrRuO_3} and CaRuO3{\rm CaRuO_3} upon introducing point defects by electron irradiation at low temperatures, and we find significant deviations from Matthiessen's rule. For a fixed irradiation dose, the induced change in resistivity {\it decreases} with increasing temperature. Moreover, for a fixed temperature, the increase in resistivity with irradiation is found to be {\it sublinear}. We suggest that the observed behavior is due to the marked anisotropic scattering of the electrons together with their relatively short mean free path (both characteristic of many metallic oxides including cuprates) which amplify effects related to the Pippard ineffectiveness condition

    Optical investigation on the electronic structures of Y_{2}Ru_{2}O_{7}, CaRuO_{3}, SrRuO_{3}, and Bi_{2}Ru_{2}O_{7}

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    We investigated the electronic structures of the bandwidth-controlled ruthenates, Y2_{2}Ru2_{2}O7_{7}, CaRuO3_{3}, SrRuO3_{3}, and Bi2_{2}Ru2% _{2}O7_{7}, by optical conductivity analysis in a wide energy region of 5 meV ∼\sim 12 eV. We could assign optical transitions from the systematic changes of the spectra and by comparison with the O 1ss x-ray absorption data. We estimated some physical parameters, such as the on-site Coulomb repulsion energy and the crystal-field splitting energy. These parameters show that the 4dd orbitals should be more extended than 3dd ones. These results are also discussed in terms of the Mott-Hubbard model.Comment: 12 pages (1 table), 3 figure

    lp-Recovery of the Most Significant Subspace among Multiple Subspaces with Outliers

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    We assume data sampled from a mixture of d-dimensional linear subspaces with spherically symmetric distributions within each subspace and an additional outlier component with spherically symmetric distribution within the ambient space (for simplicity we may assume that all distributions are uniform on their corresponding unit spheres). We also assume mixture weights for the different components. We say that one of the underlying subspaces of the model is most significant if its mixture weight is higher than the sum of the mixture weights of all other subspaces. We study the recovery of the most significant subspace by minimizing the lp-averaged distances of data points from d-dimensional subspaces, where p>0. Unlike other lp minimization problems, this minimization is non-convex for all p>0 and thus requires different methods for its analysis. We show that if 0<p<=1, then for any fraction of outliers the most significant subspace can be recovered by lp minimization with overwhelming probability (which depends on the generating distribution and its parameters). We show that when adding small noise around the underlying subspaces the most significant subspace can be nearly recovered by lp minimization for any 0<p<=1 with an error proportional to the noise level. On the other hand, if p>1 and there is more than one underlying subspace, then with overwhelming probability the most significant subspace cannot be recovered or nearly recovered. This last result does not require spherically symmetric outliers.Comment: This is a revised version of the part of 1002.1994 that deals with single subspace recovery. V3: Improved estimates (in particular for Lemma 3.1 and for estimates relying on it), asymptotic dependence of probabilities and constants on D and d and further clarifications; for simplicity it assumes uniform distributions on spheres. V4: minor revision for the published versio

    Hardware implementation of quantum stabilizers in superconducting circuits

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    Stabilizer operations are at the heart of quantum error correction and are typically implemented in software-controlled entangling gates and measurements of groups of qubits. Alternatively, qubits can be designed so that the Hamiltonian corresponds directly to a stabilizer for protecting quantum information. We demonstrate such a hardware implementation of stabilizers in a superconducting circuit composed of chains of π\pi-periodic Josephson elements. With local on-chip flux- and charge-biasing, we observe a softening of the energy band dispersion with respect to flux that is exponential in the number of frustrated plaquette elements, in close agreement with our numerical modeling.Comment: 6+30 pages, 4+18 figures, 0+6 tables, published versio

    Target and Beam Target Spin Asymmetries in Exclusive π+ and π- Electroproduction with 1.6 to 5.7 GeV Electrons

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    Beam-target double-spin asymmetries and target single-spin asymmetries in exclusive π+ and quasiexclusive π- electroproduction were obtained from scattering of 1.6- to 5.7-GeV longitudinally polarized electrons from longitudinally polarized protons (for π+) and deuterons (for π-) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic range covered is 1.1 \u3c W \u3c 2.6 GeV and 0.05 \u3c Q2 \u3c 5 GeV2, with good angular coverage in the forward hemisphere. The asymmetry results were divided into approximately 40 000 kinematic bins for π+ from free protons and 15 000 bins for π- production from bound nucleons in the deuteron. The present results are found to be in reasonable agreement with fits to previous world data for W \u3c 1.7 GeV and Q2 \u3c 0.5 GeV2, with discrepancies increasing at higher values of Q2, especially for W \u3e 1.5 GeV. Very large target-spin asymmetries are observed for W \u3e 1.6 GeV. When combined with cross-section measurements, the present results can provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q2, for resonances with masses as high as 2.3 GeV

    Non-Fermi liquid behavior and scaling of low frequency suppression in optical conductivity spectra of CaRuO3_3

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    Optical conductivity spectra σ1(ω)\sigma_1(\omega) of paramagnetic CaRuO3_3 are investigated at various temperatures. At T=10 K, it shows a non-Fermi liquid behavior of σ1(ω)∼1/ω12\sigma_1(\omega)\sim 1/{\omega}^{\frac 12}, similar to the case of a ferromagnet SrRuO3_3. As the temperature (TT) is increased, on the other hand, σ1(ω)\sigma_1(\omega) in the low frequency region is progressively suppressed, deviating from the 1/{\omega}^{\frac 12%}-dependence. Interestingly, the suppression of σ1(ω)\sigma_1(\omega) is found to scale with ω/T\omega /T at all temperatures. The origin of the % \omega /T scaling behavior coupled with the non-Fermi liquid behavior is discussed.Comment: 4 pages, 3 figure
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