56,007 research outputs found

    Quantum Faraday Effect in Double-Dot Aharonov-Bohm Ring

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    We investigate Faraday's law of induction manifested in the quantum state of Aharonov-Bohm loops. In particular, we propose a flux-switching experiment for a double-dot AB ring to verify the phase shift induced by Faraday's law. We show that the induced {\em Faraday phase} is geometric and nontopological. Our study demonstrates that the relation between the local phases of a ring at different fluxes is not arbitrary but is instead determined by Faraday's inductive law, which is in strong contrast to the arbitrary local phase of an Aharonov-Bohm ring for a given flux.Comment: Submitted to Phys. Rev. Let

    Spin resonance in the d-wave superconductor CeCoIn5

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    Neutron scattering is used to probe antiferromagnetic spin fluctuations in the d-wave heavy fermion superconductor CeCoIn5_{5} (Tc_{c}=2.3 K). Superconductivity develops from a state with slow (Γ\hbar\Gamma=0.3 ±\pm 0.15 meV) commensurate (Q0{\bf{Q_0}}=(1/2,1/2,1/2)) antiferromagnetic spin fluctuations and nearly isotropic spin correlations. The characteristic wavevector in CeCoIn5_{5} is the same as CeIn3_{3} but differs from the incommensurate wavevector measured in antiferromagnetically ordered CeRhIn5_{5}. A sharp spin resonance (Γ<0.07\hbar\Gamma<0.07 meV) at ω\hbar \omega = 0.60 ±\pm 0.03 meV develops in the superconducting state removing spectral weight from low-energy transfers. The presence of a resonance peak is indicative of strong coupling between f-electron magnetism and superconductivity and consistent with a d-wave gap order parameter satisfying Δ(q+Q0)=Δ(q)\Delta({\bf q+Q_0})=-\Delta({\bf q}).Comment: (5 pages, 4 figures, to be published in Phys. Rev. Lett.

    Using Ann to Study Sound Preference Evaluation in Urban Open Spaces

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    In soundscape research, subjective preference evaluation of a sound is crucial. Based on a series of field studies and laboratory experiments, influence of sound category and psychoacoustic parameters on sound preference evaluation is examined. It has been found that sound category and loudness and sharpness are important. Regarding a previous study, age and education level are also important to influence sound preference evaluation. In order to understand user's preference in terms of sound at a design stage, prediction of sound preference evaluation is essential. As sound preference evaluation is complicated and influenced by various factors linearly and non-linearly, artificial neural network (ANN) has been explored to make predictions of sound preference evaluation. A number of developed ANN models have been demonstrated, and it has been found that the models including input factors of sound category, loudness and sharpness produce better predictions than others. The best prediction model is the one that is based on an individual case study site. Based on the best prediction model, a mapping tool for sound preference evaluation has been developed and its usefulness for aiding landscape architects and urban designers has been demonstrated

    Diffusive propagation of wave packets in a fluctuating periodic potential

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    We consider the evolution of a tight binding wave packet propagating in a fluctuating periodic potential. If the fluctuations stem from a stationary Markov process satisfying certain technical criteria, we show that the square amplitude of the wave packet after diffusive rescaling converges to a superposition of solutions of a heat equation.Comment: 13 pages (v2: added a paragraph on the history of the problem, added some references, correct a few typos; v3 minor corrections, added keywords and subject classes

    Acoustic demands and influencing factors in facilities for the elderly

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    The aim of this study was to examine the characteristics of the elderly individuals’ acoustic demands and the effects of six influencing factors, categorized into the following three types: activity type, objective environment (number of people in a room, sound pressure level), and demographic factors (age, sex, and occupation type). In addition, we sought to identify relationships between sound preference and acoustic demands. The study was based on a semi-structured interview survey and objective measurements recorded in six facilities for the elderly in China. The results suggested that almost half of the interviewees chose not to add or abate any sound. For the remaining participants, the addition of mainly soothing music to the environment was required, indicating a considerable preference for it over natural sounds, stimulating music, and other sounds. Activity type was an important factor influencing acoustic demands, in that playing ball games and sitting still tended to engender demands for the addition of sounds, while people who were playing or watching Chinese chess did not wish to hear any sounds including soothing music. An analysis of the number of people in a room showed that if that number reached 12, demands for the abatement of sounds increased sharply, particularly for the sound of people talking. In addition, sound pressure level, age, sex, and occupation type (mental or physical work) influenced the demand for acoustic abatement, which involved the abatement of the sound of people talking or other noises and ‘no need to abate’. Natural sounds were seldom required during most activities, with the exception of chatting and sitting still, which is inconsistent with the extent to which people enjoy such sounds. However, there was a significant positive correlation between the elderly individuals’ preference for the overall acoustic environment and their demands for the addition of natural sounds. Furthermore, women were more likely to demand the addition of natural sounds, relative to men

    Reaction-diffusion with a time-dependent reaction rate: the single-species diffusion-annihilation process

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    We study the single-species diffusion-annihilation process with a time-dependent reaction rate, lambda(t)=lambda_0 t^-omega. Scaling arguments show that there is a critical value of the decay exponent omega_c(d) separating a reaction-limited regime for omega > omega_c from a diffusion-limited regime for omega < omega_c. The particle density displays a mean-field, omega-dependent, decay when the process is reaction limited whereas it behaves as for a constant reaction rate when the process is diffusion limited. These results are confirmed by Monte Carlo simulations. They allow us to discuss the scaling behaviour of coupled diffusion-annihilation processes in terms of effective time-dependent reaction rates.Comment: 11 pages, 9 figures, minor correction

    NAIP proteins are required for cytosolic detection of specific bacterial ligands in vivo.

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    NLRs (nucleotide-binding domain [NBD] leucine-rich repeat [LRR]-containing proteins) exhibit diverse functions in innate and adaptive immunity. NAIPs (NLR family, apoptosis inhibitory proteins) are NLRs that appear to function as cytosolic immunoreceptors for specific bacterial proteins, including flagellin and the inner rod and needle proteins of bacterial type III secretion systems (T3SSs). Despite strong biochemical evidence implicating NAIPs in specific detection of bacterial ligands, genetic evidence has been lacking. Here we report the use of CRISPR/Cas9 to generate Naip1(-/-) and Naip2(-/-) mice, as well as Naip1-6(Δ/Δ) mice lacking all functional Naip genes. By challenging Naip1(-/-) or Naip2(-/-) mice with specific bacterial ligands in vivo, we demonstrate that Naip1 is uniquely required to detect T3SS needle protein and Naip2 is uniquely required to detect T3SS inner rod protein, but neither Naip1 nor Naip2 is required for detection of flagellin. Previously generated Naip5(-/-) mice retain some residual responsiveness to flagellin in vivo, whereas Naip1-6(Δ/Δ) mice fail to respond to cytosolic flagellin, consistent with previous biochemical data implicating NAIP6 in flagellin detection. Our results provide genetic evidence that specific NAIP proteins function to detect specific bacterial proteins in vivo
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