For a diffusion-controlled reaction in a static, reactive bed of nonoverlapping spherical traps, upper bounds on the effective reaction-rate constant have been obtained from a variational principle of Rubinstein and Torquato. The bounds remain finite for all volume fractions and arbitrary distributions of traps. We have obtained two kinds of bounds: one kind depends on the trap volume fraction ...

BACKGROUND AND PURPOSE Estimates of blood volume and volume transfer constant are parameters commonly used to characterize hemodynamic properties of brain lesions. The purposes of this study were to compare values of volume transfer constant and estimates of blood volume in high-grade gliomas on a pixel-by-pixel basis to comprehend whether they provide different information and to compare estim...

Experiments with the flour beetle Tribolium have revealed that animal numbers were larger in cultures grown in a periodically fluctuating volume of medium than in cultures grown in a constant volume of the same average size. In this paper we derive and analyze a discrete stage-structured mathematical model that explains this phenomenon as a kind of resonance effect. Habitat volume is incorporat...

In this study we produced a new method for solving regular differential equations with step size h and Taylor series. This method analyzes a regular differential equation with initial values and step size h. this types of equations include quadratic and cubic homogenous equations with constant coeffcients and cubic and second-level equations.

Monte Carlo simulations of finite-size effects for continuum percolation in three-dimensional, rectangular sample spaces filled with spherical particles were performed. For samples with any dimension less than 10-20 times the particle diameter, finite-size effects were observed. For thin films in the finite-size regime, percolation across the thin direction of the film gave critical volume frac...

Big mammals have big (or slow) cells C ells use two basic strategies to adapt to the size of the organism in which they reside, say Van Savage and colleagues. Depending on how often they divide, comparable cells in a mouse and an elephant differ in either metabolic rate or cell volume, but usually not both. The need for such adaptation stems from simple geometry. As body volume increases, surfa...

We report constant-volume and constant-pressure simulations of the thermodynamic and dynamic properties of the low-temperature liquid and crystalline phases of the modified Stillinger-Weber (SW) model. We have found an approximately linear temperature increase of the effective Gaussian width of the distribution of inherent structures. This effect comes from non-Gaussianity of the landscape and ...