In nematic liquid crystals light is strongly scattered from director fluctuations. We are interested in the limit where the incoming light wave is scattered many times. Then, the light transport can be described by a diffusion equation for the energy density of light with diffusion constants D‖ and D⊥, respectively, parallel and perpendicular to the director. We start from a radiative transfer ...

We investigate through a generalized Langevin formalism the phenomenon of anomalous diffusion for asymptotic times, and we generalized the concept of the diffusion exponent. A method is proposed to obtain the diffusion coefficient analytically through the introduction of a time scaling factor λ. We obtain as well an exact expression for λ for all kinds of diffusion. Moreover, we show that λ is ...

Near ambient pressures, molecular diffusion dominates protonic diffusion in ice. Theoretical studies have predicted that protonic diffusion will dominate at high pressures in ice. We measured the protonic diffusion coefficient for the highest temperature molecular phase of ice VII at 400 kelvin over its entire stable pressure region. The values ranged from 10(-17) to 10(-15) square meters per s...

In this report, a diffusion analysis has been extended to a lattice containing two interstitial sites, and the results obtained are used to understand: ~1! the formation of a nitrided/unnitrided N configuration for intermediate N content and ~2! the abnormally small ~apparent! diffusion frequency factor, both of which characterize the newly developed R2Fe17 nitrides. It turns out that the diffu...

Surviving in a diverse environment requires corresponding organism responses. At the cellular level, such adjustment relies on the transcription factors (TFs) which must rapidly find their target sequences amidst a vast amount of non-relevant sequences on DNA molecules. Whether these transcription factors locate their target sites through a 1D or 3D pathway is still a matter of speculation. It ...

Saul’yev-type asymmetric schemes have been widely used in solving diffusion and advection equations. In this work, we show that Saul’yev-type schemes can be derived from the exponential splitting of the semidiscretized equation which fundamentally explains their unconditional stability. Furthermore, we show that optimal schemes are obtained by forcing each scheme’s amplification factor to match...

Transcription factor (TF) molecules translocate by facilitated diffusion (a combination of 3D diffusion around and 1D random walk on the DNA). Despite the attention this mechanism received in the last 40 years, only a few studies investigated the influence of the cellular environment on the facilitated diffusion mechanism and, in particular, the influence of "other" DNA binding proteins competi...