1,640 research outputs found

    Possible molecular states from interactions of charmed baryons

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    In this work, we perform a systematic study of possible molecular states composed of two charmed baryons including hidden-charm systems ΛcΛˉc\Lambda_c\bar{\Lambda}_c, Σc()Σˉc()\Sigma_c^{(*)}\bar{\Sigma}_c^{(*)}, and ΛcΣˉc()\Lambda_c\bar{\Sigma}_c^{(*)}, and corresponding double-charm systems ΛcΛc\Lambda_c\Lambda_c, Σc()Σc()\Sigma_c^{(*)}\Sigma_c^{(*)}, and ΛcΣc()\Lambda_c\Sigma_c^{(*)}. With the help of the heavy quark chiral effective Lagrangians, the interactions are described with π\pi, ρ\rho, η\eta, ω\omega, ϕ\phi, and σ\sigma exchanges. The potential kernels are constructed, and inserted into the quasipotential Bethe-Salpeter equation. The bound states from the interactions considered is studied by searching for the poles of the scattering amplitude. The results suggest that strong attractions exist in both hidden-charm and double-charm systems considered in the current work, and bound states can be produced in most of the systems. More experiment studies about these molecular states are suggested though the nucleon-nucleon collison at LHC and nucleon-antinucleon collison at PˉANDA\rm \bar{P}ANDA.Comment: 7 pages, 5 figure

    Quantum Entanglement in the S=1/2 Spin Ladder with Ring Exchange

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    In this paper we study the concurrence and the block-block entanglement in the S=1/2S=1/2 spin ladder with four-spin ring exchange by the exact diagonalization method of finite cluster of spins. The relationship between the global phase diagram and the ground-state entanglement is investigated. It is shown that the block-block entanglement of different block size and geometry manifests richer information of the system. We find that the extremal point of the two-site block-block entanglement on the rung locates a transition point exactly due to SU(4) symmetry at this point. The scaling behavior of the block-block entanglement is discussed. Our results suggest that the block-block entanglement can be used as a convenient marker of quantum phase transition in some complex spin systems.Comment: 5 pages, 7 figure

    Clinical effects research of the excision of pterygium combined with limbal epithelial autograft with conjunctival grafting on recurrent pterygium

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    AIM: To observe the clinical effects of the excision of pterygium combined with limbal epithelial autograft with conjunctival grafting on recurrent pterygium. <p>METHODS: Totally 84 patients(84 eyes)with first recurrent pterygium were allocated two groups: excision pterygium with limbal epithelial autograft with conjunctival(group A, 43 cases with 43 eyes)and excision of pterygium with conjunctival autograft(group B, 41 cases with 41 eyes), the post-operative follow-up period of 12 months, we analyzed the repair time of epithelium, tear break-up time(1 month and 3 months), Schirmer l test(1 month and 3 months), corneal fluorescence staining test(1 month and 3 months), and recurrent rate. <p>RESULTS: The group A had a shorter repair time of epithelium and lower recurrent rate, compared with the group B, which had statistically significant difference(<i>P</i><0.05), but there was no statistically significant difference in the tear break-up time, corneal fluorescence staining test and the Schirmer l test in 1 month and 3 months between the two groups(<i>P</i>>0.05). <p>CONCLUSION:Limbal epithelial autograft with conjunctival transplantation is a convenient, safe, effective method for the treatment of recurrent pterygium

    Developer-Intent Driven Code Comment Generation

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    Existing automatic code comment generators mainly focus on producing a general description of functionality for a given code snippet without considering developer intentions. However, in real-world practice, comments are complicated, which often contain information reflecting various intentions of developers, e.g., functionality summarization, design rationale, implementation details, code properties, etc. To bridge the gap between automatic code comment generation and real-world comment practice, we define Developer-Intent Driven Code Comment Generation, which can generate intent-aware comments for the same source code with different intents. To tackle this challenging task, we propose DOME, an approach that utilizes Intent-guided Selective Attention to explicitly select intent-relevant information from the source code, and produces various comments reflecting different intents. Our approach is evaluated on two real-world Java datasets, and the experimental results show that our approach outperforms the state-of-the-art baselines. A human evaluation also confirms the significant potential of applying DOME in practical usage, enabling developers to comment code effectively according to their own needs
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