12,633 research outputs found

    Probing signatures of bounce inflation with current observations

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    The aim of this paper is to probe the features of the bouncing cosmology with the current observational data. Basing on bounce inflation model, with high derivative term, we propose a general parametrization of primordial power spectrum which includes the typical bouncing parameters, such as bouncing time-scale, and energy scale. By applying Markov Chain Monto Carlo analysis with current data combination of Planck 2015, BAO and JLA, we report the posterior probability distributions of the parameters. We find that, bouncing models can well explain CMB observations, especially the deficit and oscillation on large scale in TT power spectrum.Comment: 17 pages, 8 figure

    State succinctness of two-way finite automata with quantum and classical states

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    {\it Two-way quantum automata with quantum and classical states} (2QCFA) were introduced by Ambainis and Watrous in 2002. In this paper we study state succinctness of 2QCFA. For any mZ+m\in {\mathbb{Z}}^+ and any ϵ<1/2\epsilon<1/2, we show that: {enumerate} there is a promise problem Aeq(m)A^{eq}(m) which can be solved by a 2QCFA with one-sided error ϵ\epsilon in a polynomial expected running time with a constant number (that depends neither on mm nor on ε\varepsilon) of quantum states and O(log1ϵ)\mathbf{O}(\log{\frac{1}{\epsilon})} classical states, whereas the sizes of the corresponding {\it deterministic finite automata} (DFA), {\it two-way nondeterministic finite automata} (2NFA) and polynomial expected running time {\it two-way probabilistic finite automata} (2PFA) are at least 2m+22m+2, logm\sqrt{\log{m}}, and (logm)/b3\sqrt[3]{(\log m)/b}, respectively; there exists a language Ltwin(m)={wcww{a,b}}L^{twin}(m)=\{wcw| w\in\{a,b\}^*\} over the alphabet Σ={a,b,c}\Sigma=\{a,b,c\} which can be recognized by a 2QCFA with one-sided error ϵ\epsilon in an exponential expected running time with a constant number of quantum states and O(log1ϵ)\mathbf{O}(\log{\frac{1}{\epsilon})} classical states, whereas the sizes of the corresponding DFA, 2NFA and polynomial expected running time 2PFA are at least 2m2^m, m\sqrt{m}, and m/b3\sqrt[3]{m/b}, respectively; {enumerate} where bb is a constant.Comment: 26pages, comments and suggestions are welcom

    Investigation on the changes of corneal curvature after non-phacoemulsification in small-incision cataract surgery with intraocular lens implantation

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    AIM: To investigate the changes of corneal curvature after non-phacoemulsification in small-incision cataract surgery with intraocular lens implantation and discuss the essence of iatrogenic astigmatism. <p>METHODS: In this study, the horizontal corneal curvature(HCC)and vertical corneal curvature(VCC)of 99 patients(116 eyes)were documented before and after cataract surgery,with the postoperative follow-up of 3d; 1, 2wk; 1, 3, 6mo; 1, 2, 3a. The difference value of the HCC and the VCC between preoperation and postoperation were calculated and statistically analyzed. <p>RESULTS: The VCC was deceased by 2.01D, while the HCC was increased by 1.62D on the 3d after surgery; the difference value of the HCC and VCC were both decreased acutely in the 3mo postoperationly(the difference value of the VCC was -0.52D and HCC was 0.46D); the difference value of the HCC and VCC both were decreased mildly after 3mo of postoperation, There was no significant difference between the difference value of HCC(0.29D)and VCC(-0.29D)at 6mo(<i>P</i>=0.801); VCC was still smaller than that of preoperation(-0.26D), and HCC was larger than that of preoperation(0.25D)at the 3a. Paired <i>t</i> test was performed in these curvature differences, which both decreased apparently from 3d to 6mo after surgery(<i>P</i><0.001), while they stayed still from 6mo to 3a postoperatively(VCC: <i>P</i>=0.284; HCC:<i>P</i>=1.000). <p>CONCLUSION: It remains astigmatism for a short time after small-incision cataract surgery and the treatment requires improvement so as to minimize the astigmatism as much as possible

    The Lifecycle and Cascade of WeChat Social Messaging Groups

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    Social instant messaging services are emerging as a transformative form with which people connect, communicate with friends in their daily life - they catalyze the formation of social groups, and they bring people stronger sense of community and connection. However, research community still knows little about the formation and evolution of groups in the context of social messaging - their lifecycles, the change in their underlying structures over time, and the diffusion processes by which they develop new members. In this paper, we analyze the daily usage logs from WeChat group messaging platform - the largest standalone messaging communication service in China - with the goal of understanding the processes by which social messaging groups come together, grow new members, and evolve over time. Specifically, we discover a strong dichotomy among groups in terms of their lifecycle, and develop a separability model by taking into account a broad range of group-level features, showing that long-term and short-term groups are inherently distinct. We also found that the lifecycle of messaging groups is largely dependent on their social roles and functions in users' daily social experiences and specific purposes. Given the strong separability between the long-term and short-term groups, we further address the problem concerning the early prediction of successful communities. In addition to modeling the growth and evolution from group-level perspective, we investigate the individual-level attributes of group members and study the diffusion process by which groups gain new members. By considering members' historical engagement behavior as well as the local social network structure that they embedded in, we develop a membership cascade model and demonstrate the effectiveness by achieving AUC of 95.31% in predicting inviter, and an AUC of 98.66% in predicting invitee.Comment: 10 pages, 8 figures, to appear in proceedings of the 25th International World Wide Web Conference (WWW 2016
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