Depending on the growth condition, bacterial colonies can exhibit different morphologies. As argued by Ben-Jacob et al. there is biological and modeling evidence that a nonlinear diffusion coefficient of the type D(b)=D(0)b(k) is a basic mechanism that underlies almost all of the patterns and generates a long-wavelength instability. We study a reaction-diffusion system with a nonlinear diffusio...

Introduction: Recent observation by infrared spectroscopy has revealed the presence of amorphous and/or crystalline silicate dusts around evolved stars or young star discs [e.g., 1-4]. The species, size, shape, composition, and orientation if they are crystalline, of the dusts control the optical properties of dusts, which further control the radiation field of discs. Thus, the formation and gr...

We propose a new type of crystal growth phenomenon—structure-dependent attachment kinetics—to explain the growth of thin ice plates from the vapor phase at temperatures near 15 C. In particular, we propose that the condensation coefficient for growth of ice prism facets increases dramatically when the width of the facet approaches atomic dimensions. This model reconciles several conflicting mea...

We consider the diffusive properties of Brownian motion in a biased periodic potential. We relate the effective diffusion coefficient to the solution of two coupled time-independent partial differential equations and solve these equations numerically by the matrix-continued-fraction (MCF) method for intermediate values of the temperature and friction coefficient. The weak-noise limit is explore...

We introduce a new, factor based bootstrap approach which is robust under heteroskedastic error terms for inference in functional coefficient models. Modeling the functional coefficient parametrically, the bootstrap approximation of a test statistic used for inference on parameter invariance is shown to hold asymptotically. In simulation studies, the factor based bootstrap inference outperforms...

This report describes a simple method for quantifying viable mycobacteria and for determining generation time. We used statistical models and computer analysis of growth curves generated for the slowly growing mycobacterium Mycobacterium paratuberculosis under controlled conditions to derive a mathematical formula relating the dependent variable, growth, to the independent variables, log10 numb...

Growth of low energy planes of perfect crystals at low supersaturation requires two-dimensional nucleation. The formation energy of nuclei of i atoms may be written G’( = -ikT In cc+G,(i), where G( is the saturation ratio. An atomistic evaluation of G,, for a simple model, is in good agreement with the classical form G,(i) = iiD’, with a constant edge energy coefficient b’, even for very small ...

We have carried out boundary-layer-resolved, unstructured fully-compressible Navier– Stokes simulations of an ultrasonic standing-wave thermoacoustic engine (TAE) model. The model is constructed as a quarter-wavelength engine, approximately 4 mm by 4 mm in size and operating at 25 kHz, and comprises a thermoacoustic stack and a coin-shaped cavity, a design inspired by Flitcroft and Symko (2013)...

The public transport infrastructure of a city is one of the most important indicators of its economic growth and development. Here we investigate the statistical properties of the public transport network in Shenyang to explore its various properties based on complex network theory. The statistical properties of the public transport system consist of the degree of a node, the average shortest p...