The coupling of transgenes to heat shock promoters is a widely applied method for regulating gene expression. In C. elegans, gene induction can be controlled temporally through timing of heat shock and spatially via targeted rescue in heat shock mutants. Here, we present a method for evoking gene expression in arbitrary cells, with single-cell resolution. We use a focused pulsed infrared laser ...

We study centred second-order in time and space discretizations of the inviscid Burgers equation. Although this equation in its continuum formulation supports non-smooth shock wave solutions, the discrete equation generically supports smooth solitary wave solutions. Using backward error analysis we derive the modified equation associated with the numerical scheme. We identify three different eq...

The piston shock problem is a classical result of shock wave theory. In this work, the analogous dispersive shock wave (DSW) problem for a fluid described by the nonlinear Schrödinger equation is analyzed. Asymptotic solutions are calculated for a piston (step potential) moving with uniform speed into a dispersive fluid at rest. In contrast to the classical case, there is a bifurcation of shock...

According to the Smolukowski-Kramers approximation, we show that the solution of the semi-linear stochastic damped wave equations μutt (t, x) = u(t, x)−ut (t, x)+ b(x, u(t, x)) + QẆ(t), u(0) = u0, ut (0) = v0, endowed with Dirichlet boundary conditions, converges as μ goes to zero to the solution of the semi-linear stochastic heat equation ut (t, x) = u(t, x)+b(x, u(t, x))+QẆ(t), u(0) = u0, end...

Shock wave theory was first studied for gas dynamics, for which shocks appear as compression waves. A shock wave is characterized as a sharp transition, even discontinuity in the flow. In fact, shocks appear in many different physical situation and represent strong nonlinearity of the physical processes. Important progresses have been made on shock wave theory in recent years. We will survey th...

We investigate the dynamics of weakly-modulated nonlinear wave trains. For reaction-diffusion systems and for the complex Ginzburg–Landau equation, we establish rigorously that slowly varying modulations of wave trains are well approximated by solutions to the Burgers equation over the natural time scale. In addition to the validity of the Burgers equation, we show that the viscous shock profil...

Shock tubes have become widely used to study thermodynamic processes in high temperature gas flows [1], [2] and chemical kinetics [3], [4]. Flow parameters behind incident and reflected shock waves were analyzed by Gaydon and Hurle [1], Bazhenova et al. [2], Sturtevant and Slachmuylders [5], Goldsworthy [6], Johannesen et al. [7], and Hanson et al. [8]. It was found that the gas behind the refl...

A Bose-Einstein condensate (BEC) is a quantum fluid that gives rise to interesting shock wave nonlinear dynamics. Experiments depict a BEC that exhibits behavior similar to that of a shock wave in a compressible gas, eg. traveling fronts with steep gradients. However, the governing Gross-Pitaevskii (GP) equation that describes the mean field of a BEC admits no dissipation hence classical dissip...

The structure of a two-phase steady detonation in a granulated solid propellant is studied, and existence conditions for a one-dimensional, steady two-phase detonation are given. Ordinary differential equations from continuum mixture theory are solved numerically to determine steady wave structure. In the limiting case where heat transfer and compaction effects are negligible, the model reduces...