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    On robust stability of stochastic genetic regulatory networks with time delays: A delay fractioning approach

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    Copyright [2009] IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.Robust stability serves as an important regulation mechanism in system biology and synthetic biology. In this paper, the robust stability analysis problem is investigated for a class of nonlinear delayed genetic regulatory networks with parameter uncertainties and stochastic perturbations. The nonlinear function describing the feedback regulation satisfies the sector condition, the time delays exist in both translation and feedback regulation processes, and the state-dependent Brownian motions are introduced to reflect the inherent intrinsic and extrinsic noise perturbations. The purpose of the addressed stability analysis problem is to establish some easy-to-verify conditions under which the dynamics of the true concentrations of the messenger ribonucleic acid (mRNA) and protein is asymptotically stable irrespective of the norm-bounded modeling errors. By utilizing a new Lyapunov functional based on the idea of “delay fractioning”, we employ the linear matrix inequality (LMI) technique to derive delay-dependent sufficient conditions ensuring the robust stability of the gene regulatory networks. Note that the obtained results are formulated in terms of LMIs that can easily be solved using standard software packages. Simulation examples are exploited to illustrate the effectiveness of the proposed design procedures

    Unipolar and bipolar fatigue in antiferroelectric lead zirconate thin films and evidences for switching-induced charge injection inducing fatigue

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    For the first time, we show that unipolar fatigue does occur in antiferroelectric capacitors, confirming the predictions of a previous work [Appl. Phys. Lett., 94, 072901 (2009)]. We also show that unipolar fatigue in antiferroelectrics is less severe than bipolar fatigue if the driving field is of the same magnitude. This phenomenon has been attributed to the switching-induced charge injection, the main cause for polarization fatigue in ferroelectric and antiferroelectric materials. Other evidences for polarization fatigue caused by the switching-induced charge injection from the nearby electrode rather than the charge injection during stable/quasi-stable leakage current stage are also discussed.Comment: 10 pages and 2 figure

    Religious Identity Formation Among Adolescents: The Role of Religious Secondary Schools

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    The purpose of this article is to examine the role religious secondary schools play in the religious identity formation of adolescents. Although several research studies have found a correlation between enrollment in private religious schools and adolescents’ religious identity formation, the researchers of these studies have only speculated about which specific characteristics of religious schools are responsible for this formation in the lives of adolescents. Through a review of the literature, the present article identifies several characteristics of religious secondary schools that may contribute to the process of religious identity formation: a community of religious peers, the presence of religious adults, and an exposure to religious instruction. Implications for Christian secondary school practitioners are also discussed