Implementation of a Social Network Information Dissemination Model Incorporating Negative Relationships

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

The partial decay widths and production mechanism of the three pentaquark states, $P_{\psi}^{N}(4312)$, $P_{\psi}^{N}(4440)$, and $P_{\psi}^{N}(4457)$, 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 $\bar{D}^{(*)}\Sigma_{c}^{(*)}$, $\bar{D}^{*}\Lambda_c$, $\bar{D}\Lambda_c$, $J/\psi p$, and $\eta_c p$ coupled-channel interactions to dynamically generate the multiplet of hidde-charm pentaquark molecules by reproducing the masses and widths of $P_{\psi}^{N}(4312)$, $P_{\psi}^{N}(4440)$, and $P_{\psi}^{N}(4457)$. Assuming that the pentaquark molecules are produced in the $\Lambda_b$ decay via the triangle diagrams, where $\Lambda_{b}$ firstly decays into $D_{s}^{(\ast)}\Lambda_{c}$, then $D_{s}^{(\ast)}$ scatters into $\bar{D}^{(\ast)}K$, and finally the molecules are dynamically generated by the $\bar{D}^{(\ast)}\Lambda_{c}$ interactions, we calculate the branching fractions of the decays $\Lambda_b \to {P_{\psi}^{N}}K$ using the effective Lagrangian approach. With the partial decay widths of these pentaquark molecules, we further estimate the branching fraction of the decays $\Lambda_b \to ( P_{\psi}^{N} \to J/\psi p )K$ and $\Lambda_b \to ( P_{\psi}^{N}\to \bar{D}^* \Lambda_c )K$. Our results show that the pentaquark states $P_{\psi}^{N}(4312)$, $P_{\psi}^{N}(4440)$, and $P_{\psi}^{N}(4457)$ as hadronic molecules can be produced in the $\Lambda_b$ decay, and on the other hand their heavy quark spin symmetry partners are invisible in the $J/\psi p$ invariant mass distribution because of the small production rates. Our studies show that is possible to observe some of the pentaquark states in the $\Lambda_b\to \bar{D}^*\Lambda_c K$ decays

Interfacial effects on the polarization of BiFeO3BiFeO_{3} films

By considering an interfacial layer between the electrode and the $BiFeO_{3}$($BFO$) layer, the polarization and the hysteresis behavior of $BFO$ 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 $BFO$ film can be independent on the film thickness under an adequate applied field.Comment: 3 pages, 2 figure

Three-body molecules DˉDˉ∗Σc\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)

The nature of the three pentaquark states, $P_{c}(4312)$, $P_{c}(4440)$ and $P_{c}(4457)$, discovered by the LHCb Collaboration in 2019, is still under debate, although the $\bar{D}^{(\ast)}\Sigma_{c}$ molecular interpretation seems to be the most popular. In this work, by adding a $\bar{D}$ meson into the $\bar{D}^{\ast}\Sigma_{c}$ pair, we investigate the mass and decay width of the three-body molecules $\bar{D}\bar{D}^{\ast}\Sigma_{c}$ and explore the correlation between the existence of the $\bar{D}\bar{D}^{\ast}\Sigma_{c}$ molecules with the existence of $\bar{D}^{(\ast)}\Sigma_{c}$ and $\bar{D}^{\ast}\bar{D}$ two-body molecules. The latter can be identified with the doubly charmed tetraquark state $T_{cc}$ recently discovered by the LHCb Collaboration. Based on the molecular nature of $P_{c}(4312)$, $P_{c}(4440)$, $P_{c}(4457)$, and $T_{cc}$, our results indicate that there exist two three-body bound states of $\bar{D}\bar{D}^{\ast}\Sigma_{c}$ with $I(J^{P})=1(1/2^{+})$ and $I(J^{P})=1(3/2^{+})$, and binding energies $37.24$ MeV and $29.63$ MeV below the $\bar{D}\bar{D}^{\ast}\Sigma_{c}$ mass threshold. In addition, we find that the mass splitting of these two three-body molecules are correlated to the mass splitting of $P_{c}(4440)$ and $P_{c}(4457)$, which offers a non-trivial way to reveal the molecular nature of these states. The partial widths of two $\bar{D}\bar{D}^{\ast}\Sigma_{c}$ molecules decaying into $J/\psi p \bar{D}$ and $J/\psi p \bar{D}^{\ast}$ are found to be several MeV. We recommend the experimental searches for the $\bar{D}\bar{D}^{\ast}\Sigma_{c}$ molecules in the $J/\psi p \bar{D}$ and $J/\psi p \bar{D}^{\ast}$ invariant mass distributions

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

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