3,575 research outputs found

    Re-Study on the wave functions of Υ(nS)\Upsilon(nS) states in LFQM and the radiative decays of Υ(nS)→ηb+γ\Upsilon(nS)\to \eta_b+\gamma

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    The Light-front quark model (LFQM) has been applied to calculate the transition matrix elements of heavy hadron decays. However, it is noted that using the traditional wave functions of the LFQM given in literature, the theoretically determined decay constants of the Υ(nS)\Upsilon(nS) obviously contradict to the data. It implies that the wave functions must be modified. Keeping the orthogonality among the nSnS states and fitting their decay constants we obtain a series of the wave functions for Υ(nS)\Upsilon(nS). Based on these wave functions and by analogy to the hydrogen atom, we suggest a modified analytical form for the Υ(nS)\Upsilon(nS) wave functions. By use of the modified wave functions, the obtained decay constants are close to the experimental data. Then we calculate the rates of radiative decays of Υ(nS)→ηb+γ\Upsilon(nS)\to \eta_b+\gamma. Our predictions are consistent with the experimental data on decays Υ(3S)→ηb+γ\Upsilon(3S)\to \eta_b+\gamma within the theoretical and experimental errors.Comment: 10 pages, 2 figures, 1 table. Typos corrected and more discussions added. accepted for publication in Physical Review

    BLISTER-regulated vegetative growth is dependent on the protein kinase domain of ER stress modulator IRE1A in Arabidopsis thaliana

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    The unfolded protein response (UPR) is required for protein homeostasis in the endoplasmic reticulum (ER) when plants are challenged by adverse environmental conditions. Inositol-requiring enzyme 1 (IRE1), the bifunctional protein kinase / ribonuclease, is an important UPR regulator in plants mediating cytoplasmic splicing of the mRNA encoding the transcription factor bZIP60. This activates the UPR signaling pathway and regulates canonical UPR genes. However, how the protein activity of IRE1 is controlled during plant growth and development is largely unknown. In the present study, we demonstrate that the nuclear and Golgi-localized protein BLISTER (BLI) negatively controls the activity of IRE1A/IRE1B under normal growth condition in Arabidopsis. Loss-of-function mutation of BLI results in chronic up-regulation of a set of both canonical UPR genes and non-canonical UPR downstream genes, leading to cell death and growth retardation. Genetic analysis indicates that BLI-regulated vegetative growth phenotype is dependent on IRE1A/IRE1B but not their canonical splicing target bZIP60. Genetic complementation with mutation analysis suggests that the D570/K572 residues in the ATP-binding pocket and N780 residue in the RNase domain of IRE1A are required for the activation of canonical UPR gene expression, in contrast, the D570/K572 residues and D590 residue in the protein kinase domain of IRE1A are important for the induction of non-canonical UPR downstream genes in the BLI mutant background, which correlates with the shoot growth phenotype. Hence, our results reveal the important role of IRE1A in plant growth and development, and BLI negatively controls IRE1A’s function under normal growth condition in plants

    Blind separation of cyclostationary signals from instantaneous mixtures

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    This paper presents a new approach for blind separation of unknown cyclostationary signals from instantaneous mixtures. The proposed method can perfectly separate the mixed source signals so long as they have either different cyclic frequencies or clock phases. This is a weaker condition than those required by the algorithms. The separation criterion is to diagonalize a polynomial matrix whose coefficient matrices consist of the correlation and cyclic correlation matrices, at time delay &tau;=0, of multiple measurements. <br /

    A Possibility of Search for New Physics at LHCb

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    It is interesting to search for new physics beyond the standard model at LHCb. We suggest that weak decays of doubly charmed baryon such as Ξcc(3520)+,Ξcc++\Xi_{cc}(3520)^+, \Xi_{cc}^{++} to charmless final states would be a possible signal for new physics. In this work, we consider two models, i.e. the unparticle and Z′Z' as examples to study such possibilities. We also discuss the cases for Ξbb0,Ξbb−\Xi^0_{bb}, \Xi_{bb}^- which have not been observed yet, but one can expect to find them when LHCb begins running. Our numerical results show that these two models cannot result in sufficiently large decay widths, therefore if such modes are observed at LHCb, there must be a new physics other than the unparticle or Z′Z' models.Comment: 7 pages, 3 figures, 1 table. More references and discussion adde

    Enhancing consumer engagement in online shopping platforms through economic incentives

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    Online shopping is becoming part of people’s everyday life experience. Recognizing the tremendous growth of online shopping, it is important to investigate how to achieve success in the competitive environment. The purpose of this paper is to understand the development of consumer engagement process and investigate how to encourage consumers to engage in online shopping platform. Based on information processing theory, we propose a more complete framework to examine consumer engagement process by adding calculative commitment and economic incentives. In our framework, economic incentives, considered as both cognitive and emotive basis for purchase, moderates the process of consumer engagement. We believe our study will provide a deeper understanding of consumer engagement process

    Interference Mitigation for Cognitive Radio MIMO Systems Based on Practical Precoding

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    In this paper, we propose two subspace-projection-based precoding schemes, namely, full-projection (FP)- and partial-projection (PP)-based precoding, for a cognitive radio multiple-input multiple-output (CR-MIMO) network to mitigate its interference to a primary time-division-duplexing (TDD) system. The proposed precoding schemes are capable of estimating interference channels between CR and primary networks, and incorporating the interference from the primary to the CR system into CR precoding via a novel sensing approach. Then, the CR performance and resulting interference of the proposed precoding schemes are analyzed and evaluated. By fully projecting the CR transmission onto a null space of the interference channels, the FP-based precoding scheme can effectively avoid interfering the primary system with boosted CR throughput. While, the PP-based scheme is able to further improve the CR throughput by partially projecting its transmission onto the null space.Comment: 12 pages, 4 figures, submitted to the IEEE Trans. Wireless Communications in April 201

    Phase-locked scroll waves defy turbulence induced by negative filament tension

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    Scroll waves in a three-dimensional media may develop into turbulence due to negative tension of the filament. Such negative tension-induced instability of scrollwaves has been observed in the Belousov-Zhabotinsky reaction systems. Here we propose a method to restabilize scroll wave turbulence caused by negative tension in three-dimensional chemical excitable media using a circularly polarized (rotating) external field. The stabilization mechanism is analyzed in terms of phase-locking caused by the external field, which makes the effective filament tension positive. The phase-locked scrollwaves that have positive tension and higher frequency defy the turbulence and finally restore order. A linear theory for the change of filament tension caused by a generic rotating external field is presented and its predictions closely agree with numerical simulations
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