149 research outputs found

    Equation-free Dynamic Renormalization of a KPZ-type Equation

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    In the context of equation-free computation, we devise and implement a procedure for using short-time direct simulations of a KPZ type equation to calculate the self-similar solution for its ensemble averaged correlation function. The method involves "lifting" from candidate pair-correlation functions to consistent realization ensembles, short bursts of KPZ-type evolution, and appropriate rescaling of the resulting averaged pair correlation functions. Both the self-similar shapes and their similarity exponents are obtained at a computational cost significantly reduced to that required to reach saturation in such systems

    A note on Gabor coefficient computing with Taylor series expansion

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    We present an improvement on a previously proposed method for computing Gabor coefficients of characteristic functions with polygonal cross sections, based on a Taylor series expansion and Olver's algorithm. Several requirements are proposed to make the method more robust. Numerical evidence is given to show a convergent solution can be obtained based on a sufficiently high truncation number and working precision

    Local normal vector field formulation for polygonal building blocks in a Gabor representation

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    The usage of a spatial spectral domain integralequation solver for electromagnetic scattering from dielectricobjects provides a means to execute scattering simulationsfor lithography.We consider the extension of the localnormal vector field formulation to support polygonal buildingblocks in a Gabor series representation of functions.The usage of a spatial spectral domain integral equation solver for electromagnetic scattering from dielectric objects provides a means to execute scattering simulations for lithography. We consider the extension of the local normal vector field formulation to support polygonal building blocks in a Gabor series representation of functions

    Two-Dimensional Diffusion in the Presence of Topological Disorder

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    How topological defects affect the dynamics of particles hopping between lattice sites of a distorted, two-dimensional crystal is addressed. Perturbation theory and numerical simulations show that weak, short-ranged topological disorder leads to a finite reduction of the diffusion coefficient. Renormalization group theory and numerical simulations suggest that longer-ranged disorder, such as that from randomly placed dislocations or random disclinations with no net disclinicity, leads to subdiffusion at long times.Comment: 10 pages, 6 figure

    High-Precision Tuning of State for Memristive Devices by Adaptable Variation-Tolerant Algorithm

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    Using memristive properties common for the titanium dioxide thin film devices, we designed a simple write algorithm to tune device conductance at a specific bias point to 1% relative accuracy (which is roughly equivalent to 7-bit precision) within its dynamic range even in the presence of large variations in switching behavior. The high precision state is nonvolatile and the results are likely to be sustained for nanoscale memristive devices because of the inherent filamentary nature of the resistive switching. The proposed functionality of memristive devices is especially attractive for analog computing with low precision data. As one representative example we demonstrate hybrid circuitry consisting of CMOS summing amplifier and two memristive devices to perform analog multiply and accumulate computation, which is a typical bottleneck operation in information processing.Comment: 20 pages, 6 figure

    Transcription Profile Analysis Reveals That Zygotic Division Results in Uneven Distribution of Specific Transcripts in Apical/Basal Cells of Tobacco

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    BACKGROUND: Asymmetric zygotic division in higher plants results in the formation of an apical cell and a basal cell. These two embryonic cells possess distinct morphologies and cell developmental fates. It has been proposed that unevenly distributed cell fate determinants and/or distinct cell transcript profiles may be the underlying reason for their distinct fates. However, neither of these hypotheses has convincing support due to technical limitations. METHODOLOGY/PRINCIPAL FINDINGS: Using laser-controlled microdissection, we isolated apical and basal cells and constructed cell type-specific cDNA libraries. Transcript profile analysis revealed difference in transcript composition. PCR and qPCR analysis confirmed that transcripts of selected embryogenesis-related genes were cell-type preferentially distributed. Some of the transcripts that existed in zygotes were found distinctly existed in apical or basal cells. The cell type specific de novo transcription was also found after zygotic cell division. CONCLUSIONS/SIGNIFICANCE: Thus, we found that the transcript diversity occurs between apical and basal cells. Asymmetric zygotic division results in the uneven distribution of some embryogenesis related transcripts in the two-celled proembryos, suggesting that a differential distribution of some specific transcripts in the apical or basal cells may involve in guiding the two cell types to different developmental destinies
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