174,506 research outputs found

    China: disidencia y ciberespacio

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    La reciente condena de Liu Xiaobo, prominente disidente chino, se ha producido en medio de un conflicto de grandes intereses empresariales y políticos, en el marco de un ciberespacio altamente estratégico. Este análisis se propone, primero, explicar la relevancia de la detención de Liu Xiaobo y su importancia en relación con el activismo chino de significado político y social de los últimos años. A continuación ofrece algunas interpretaciones sobre el enfrentamiento Google-Pekín, casi coincidente con el caso Liu y relacionado con ciberataques y censura. Por último, analiza aspectos del pulso de poder en el ciberespacio

    On the qq-log-convexity conjecture of Sun

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    In his study of Ramanujan-Sato type series for 1/π1/\pi, Sun introduced a sequence of polynomials Sn(q)S_n(q) as given by Sn(q)=k=0n(nk)(2kk)(2(nk)nk)qk,S_n(q)=\sum\limits_{k=0}^n{n\choose k}{2k\choose k}{2(n-k)\choose n-k}q^k, and he conjectured that the polynomials Sn(q)S_n(q) are qq-log-convex. By imitating a result of Liu and Wang on generating new qq-log-convex sequences of polynomials from old ones, we obtain a sufficient condition for determining the qq-log-convexity of self-reciprocal polynomials. Based on this criterion, we then give an affirmative answer to Sun's conjecture

    New Liu Estimators for the Poisson Regression Model: Method and Application

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    A new shrinkage estimator for the Poisson model is introduced in this paper. This method is a generalization of the Liu (1993) estimator originally developed for the linear regression model and will be generalised here to be used instead of the classical maximum likelihood (ML) method in the presence of multicollinearity since the mean squared error (MSE) of ML becomes inflated in that situation. Furthermore, this paper derives the optimal value of the shrinkage parameter and based on this value some methods of how the shrinkage parameter should be estimated are suggested. Using Monte Carlo simulation where the MSE and mean absolute error (MAE) are calculated it is shown that when the Liu estimator is applied with these proposed estimators of the shrinkage parameter it always outperforms the ML. Finally, an empirical application has been considered to illustrate the usefulness of the new Liu estimators.Estimation; MSE; MAE; Multicollinearity; Poisson; Liu; Simulation

    Osteoinductive and Antibacterial Biomaterials for Bone Tissue Engineering

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    Wismeyer, D. [Promotor]Liu, Y. [Copromotor

    SCF E3 Ligase Substrates Switch from CAN-D to Can-ubiquitylate

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    Liu et al. (2018) report a mathematical model predicting how the cellular repertoire of SCF E3 ligases is assembled by “adaptive exchange on demand,” with the limited pool of CUL1 scanning the vast sea of F-box proteins for those with substrates demanding ubiquitylation

    The nature of attraction between like charged rods

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    Comment on the paper of Ha and Liu (Phys. Rev. Lett. {\bf 79}, 1289 (1997)) regarding the nature of attraction between like charged rods. We demostrate that their results do not produce the correct low temperature limit.Comment: Comment to appear in Phys. Rev. Let

    Comment on 'A new nanoscale metastable iron phase in carbon steels'

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    We show that the selected area diffraction patterns presented in a recent paper (T. Liu et al. Sci. Rep. 2015 5, 15331) do not prove the existence of a new hexagonal phase in martensitic steels. They can be actually simulated by twin effects.Comment: 5 pagesm 3 figure
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