The Brownian motion of molecules at thermal equilibrium usually has a finite correlation time and will eventually be randomized after a long delay time, so that their displacement follows the Gaussian statistics. This is true even when the molecules have experienced a complex environment with a finite correlation time. Here, we report that the lateral motion of the acetylcholine receptors on live muscle cell membranes does not follow the Gaussian statistics for normal Brownian diffusion. From a careful analysis of a large volume of the protein trajectories obtained over a wide range of sampling rates and long durations, we find that the normalized histogram of the protein displacements shows an exponential tail, which is robust and universal for cells under different conditions. The experiment indicates that the observed non-Gaussian statistics and dynamic heterogeneity are inherently linked to the slow-active remodelling of the underlying cortical actin network.

High-precision measurements of the Nusselt number Nu as a function of the Rayleigh number Ra have been made in water-filled 1m diameter cylindrical cells of aspect ratio $\Gamma {=} $0.67, 1, 2, 5, 10 and 20. The measurements were conducted at the Prandtl number $Pr {\approx} 4$ with Ra varying from $1{\times} 10^7$ to $5{\times} 10^{12}$. When corrections for the finite conductivity of the top and bottom plates are made, the estimates obtained of $Nu_{\infty}$ for perfectly conducting plates may be described by a combination of two power laws $Nu_{\infty} {=} C_{1}(\Gamma)Ra^{\beta_1}+C_{2}(\Gamma)Ra^{\beta_2}$ for all the aspect ratios. The fitted exponents $\beta_1 {=}0.211$ and $\beta_2 {=} 0.332$ are very close to $1/5$ and $1/3$ respectively, which have been predicted by Grossmann & Lohse for the II$_u$ and IV$_u$ regimes in their model. It is also found that $Nu_{\infty}$ is generally smaller for larger $\Gamma$ but the difference is only a few percent and for $\Gamma{\gtrsim} 10$ the asymptotic large-$\Gamma$ behaviour may have been reached.

Current-induced switching from a metallic to an insulating state is observed in phase-separated states of (La(1-y)Pr(y))0.7Ca0.3MnO3 (y=0.7) and Nd(0.5)Ca(0.5)Mn(1-z)Cr(z)O3 (z=0.03) crystals. The application of magnetic fields to this current-induced insulating state causes a pronounced low-field negative magnetoresistance effect [rho(H)/rho(0)=10(-3) at H=1 kOe]. The application of a constant voltage also causes the breakdown of the Ohmic relation above a threshold voltage. At voltages higher than this threshold value, oscillations in currents are observed. This oscillation is well reproduced by a simple model of local switching of a percolative conduction path.

Rare massive eruption of thermal plumes causes random reversals of the large-scale flow in turbulent thermal convection.