2,367 research outputs found

    Implementation of a Social Network Information Dissemination Model Incorporating Negative Relationships

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    For the study of information dissemination in online social networks, most existing information dissemination models include only positive relationships, ignoring the existence and importance of negative relationships, and do not consider the influence of inter-individual relationship polarity on dissemination. To solve these problems, we propose a social network information dissemination model incorporating negative relationships in this paper. Drawing on the state concept of the SIR (Susceptible Infected Recovered) model, the three types of SIR states are subdivided into five sub-states. Combining the advantages of the viewpoint evolution model, the influence of relational polarity on node attitudes is added to the modeling of the propagation process. The experiment proves that the method proposed in this paper can show more specifically the changing trend in the number of propagation nodes with different attitudes and portray the process of information propagation in online social networks

    Production rates of hidden-charm pentaquark molecules in Λb\Lambda_b decays

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    The partial decay widths and production mechanism of the three pentaquark states, PψN(4312)P_{\psi}^{N}(4312), PψN(4440)P_{\psi}^{N}(4440), and PψN(4457)P_{\psi}^{N}(4457), discovered by the LHCb Collaboration in 2019, are still under debate. In this work, we employ the contact-range effective field theory approach to construct the Dˉ()Σc()\bar{D}^{(*)}\Sigma_{c}^{(*)}, DˉΛc\bar{D}^{*}\Lambda_c, DˉΛc\bar{D}\Lambda_c, J/ψpJ/\psi p, and ηcp\eta_c p coupled-channel interactions to dynamically generate the multiplet of hidde-charm pentaquark molecules by reproducing the masses and widths of PψN(4312)P_{\psi}^{N}(4312), PψN(4440)P_{\psi}^{N}(4440), and PψN(4457)P_{\psi}^{N}(4457). Assuming that the pentaquark molecules are produced in the Λb\Lambda_b decay via the triangle diagrams, where Λb\Lambda_{b} firstly decays into Ds()ΛcD_{s}^{(\ast)}\Lambda_{c}, then Ds()D_{s}^{(\ast)} scatters into Dˉ()K\bar{D}^{(\ast)}K, and finally the molecules are dynamically generated by the Dˉ()Λc\bar{D}^{(\ast)}\Lambda_{c} interactions, we calculate the branching fractions of the decays ΛbPψNK\Lambda_b \to {P_{\psi}^{N}}K using the effective Lagrangian approach. With the partial decay widths of these pentaquark molecules, we further estimate the branching fraction of the decays Λb(PψNJ/ψp)K \Lambda_b \to ( P_{\psi}^{N} \to J/\psi p )K and Λb(PψNDˉΛc)K \Lambda_b \to ( P_{\psi}^{N}\to \bar{D}^* \Lambda_c )K . Our results show that the pentaquark states PψN(4312)P_{\psi}^{N}(4312), PψN(4440)P_{\psi}^{N}(4440), and PψN(4457)P_{\psi}^{N}(4457) as hadronic molecules can be produced in the Λb\Lambda_b decay, and on the other hand their heavy quark spin symmetry partners are invisible in the J/ψpJ/\psi p invariant mass distribution because of the small production rates. Our studies show that is possible to observe some of the pentaquark states in the ΛbDˉΛcK\Lambda_b\to \bar{D}^*\Lambda_c K decays

    Interfacial effects on the polarization of BiFeO3BiFeO_{3} films

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    By considering an interfacial layer between the electrode and the BiFeO3BiFeO_{3}(BFOBFO) layer, the polarization and the hysteresis behavior of BFOBFO film are simulated. It is found that the non-ferroelectric interface will increase the coercive field, and remarkably suppress the polarization of the ultrathin film under low applied fields. Due to the competition between the interfacial effect and the internal compressive stress, the maximum polarization on the P-E loop of a BFOBFO film can be independent on the film thickness under an adequate applied field.Comment: 3 pages, 2 figure

    A case report of secondary B-cell acute lymphoblastic leukemia treated with a combination of FLT3 inhibitor and decitabine

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    Secondary acute lymphoblastic leukemia (s-ALL) refers to acute lymphoblastic leukemia that occurs after a previous malignant tumor, including therapy-related acute lymphoblastic leukemia (t-ALL) and prior malignant tumor acute lymphoblastic leukemia (pm-ALL). We report a case of a 51-year-old female patient who developed acute lymphoblastic leukemia 14 years after being diagnosed with diffuse large B-cell lymphoma (DLBCL). The patient was unresponsive to conventional chemotherapy for acute lymphoblastic leukemia (ALL) and achieved remission with a combination of sorafenib and decitabine based on the molecular biology characteristics of her B-ALL

    Three-body molecules DˉDˉΣc\bar{D}\bar{D}^{\ast}\Sigma_{c}- understanding the nature of TccT_{cc}, Pc(4312)P_{c}(4312), Pc(4440)P_{c}(4440) and Pc(4457)P_{c}(4457)

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    The nature of the three pentaquark states, Pc(4312)P_{c}(4312), Pc(4440)P_{c}(4440) and Pc(4457)P_{c}(4457), discovered by the LHCb Collaboration in 2019, is still under debate, although the Dˉ()Σc\bar{D}^{(\ast)}\Sigma_{c} molecular interpretation seems to be the most popular. In this work, by adding a Dˉ\bar{D} meson into the DˉΣc\bar{D}^{\ast}\Sigma_{c} pair, we investigate the mass and decay width of the three-body molecules DˉDˉΣc\bar{D}\bar{D}^{\ast}\Sigma_{c} and explore the correlation between the existence of the DˉDˉΣc\bar{D}\bar{D}^{\ast}\Sigma_{c} molecules with the existence of Dˉ()Σc\bar{D}^{(\ast)}\Sigma_{c} and DˉDˉ\bar{D}^{\ast}\bar{D} two-body molecules. The latter can be identified with the doubly charmed tetraquark state TccT_{cc} recently discovered by the LHCb Collaboration. Based on the molecular nature of Pc(4312)P_{c}(4312), Pc(4440)P_{c}(4440), Pc(4457)P_{c}(4457), and TccT_{cc}, our results indicate that there exist two three-body bound states of DˉDˉΣc\bar{D}\bar{D}^{\ast}\Sigma_{c} with I(JP)=1(1/2+)I(J^{P})=1(1/2^{+}) and I(JP)=1(3/2+)I(J^{P})=1(3/2^{+}), and binding energies 37.2437.24 MeV and 29.6329.63 MeV below the DˉDˉΣc\bar{D}\bar{D}^{\ast}\Sigma_{c} mass threshold. In addition, we find that the mass splitting of these two three-body molecules are correlated to the mass splitting of Pc(4440)P_{c}(4440) and Pc(4457)P_{c}(4457), which offers a non-trivial way to reveal the molecular nature of these states. The partial widths of two DˉDˉΣc\bar{D}\bar{D}^{\ast}\Sigma_{c} molecules decaying into J/ψpDˉJ/\psi p \bar{D} and J/ψpDˉJ/\psi p \bar{D}^{\ast} are found to be several MeV. We recommend the experimental searches for the DˉDˉΣc\bar{D}\bar{D}^{\ast}\Sigma_{c} molecules in the J/ψpDˉJ/\psi p \bar{D} and J/ψpDˉJ/\psi p \bar{D}^{\ast} invariant mass distributions

    Broad Inhibition Sharpens Orientation Selectivity by Expanding Input Dynamic Range in Mouse Simple Cells

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    SummaryOrientation selectivity (OS) is an emergent property in the primary visual cortex (V1). How OS arises from synaptic circuits remains unsolved. Here, in vivo whole-cell recordings in the mouse V1 revealed that simple cells received broadly tuned excitation and even more broadly tuned inhibition. Excitation and inhibition shared a similar orientation preference and temporally overlapped substantially. Neuron modeling and dynamic-clamp recording further revealed that excitatory inputs alone would result in membrane potential responses with significantly attenuated selectivity, due to a saturating input-output function of the membrane filtering. Inhibition ameliorated the attenuation of excitatory selectivity by expanding the input dynamic range and caused additional sharpening of output responses beyond unselectively suppressing responses at all orientations. This “blur-sharpening” effect allows selectivity conveyed by excitatory inputs to be better expressed, which may be a general mechanism underlying the generation of feature-selective responses in the face of strong excitatory inputs that are weakly biased
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