Transcription factor (TF) proteins rapidly locate unique target sites on long genomic DNA molecules--and bind to them--during gene regulation. The search mechanism is known to involve a combination of three-dimensional diffusion through the bulk of the cell and one-dimensional sliding diffusion along the DNA. It is believed that the surprisingly high target binding rates of TF proteins relies o...

We investigate velocity statistics of an impurity immersed in a uniform granular fluid. We consider the cooling phase, and obtain scaling solutions of the inelastic Maxwell model analytically. First, we analyze identical fluid-fluid and fluid-impurity collision rates. We show that light impurities have similar velocity statistics as the fluid background, although their temperature is generally ...

We extract at redshift z = 0 a Milky Way sized object including gas, stars and dark matter (DM) from a recent, high-resolution cosmological N-body simulation with baryons. Its resolution is su cient to witness the formation of a rotating disk and bulge at the center of the halo potential, therefore providing a realistic description of the birth and the evolution of galactic structures in the ΛC...

We report measurements of ion energy distributions of ionized species in titanium and aluminium filtered cathodic vacuum arcs operating in oxygen and nitrogen gas atmospheres. The ion energy distributions were recorded using a Hiden mass selected ion energy analyzer. The results show that a significant reduction in ion energies and a change in the shape of ion energy distributions occurs as the...

We study, globaly in time, the velocity distribution f(v; t) of a spatially homogeneous system that models a system of electrons in a weakly ionized plasma, subjected to a constant external electric eld E. The density f satis es a Boltzmann type kinetic equation containing a full nonlinear electron-electron collision term as well as linear terms representing collisions with reservoir particles ...

Abstract The calculation of fusion reactivity involves a complex six-dimensional integral that takes into account the cross section and velocity distributions two reactants. However, more simplified one-dimensional form can be useful in certain cases, such as for studying yield or diagnosing ion energy spectra. This simpler has been derived few special combination Maxwellian distributions, beam...

We have used Monte Carlo simulations of O+ velocity distributions in the high latitude Fregion to improve the calculation of incoherent radar spectra in auroral ionosphere. The Monte Carlo simulation includes ionneutral, O+-O collisions (resonant charge exchange and polarization interaction) as well as O+-O+ Coulomb self-collisions. At high altitudes, atomic oxygen O and atomic oxygen ion O+ do...

Models of the continuum radiation from accreting hot plasmas typically assume that the plasma heating mechanism produces energetic particles distributed in energy either as a Maxwellian (the “thermal” models) or as an extended power law (the “non-thermal” models). The reality, however, is that neither description is probably accurate. In other astrophysical contexts where we have been able to o...

We introduce a new micro/macro decomposition of collisional kinetic equations which naturally incorporates the exact space boundary conditions. The idea is to write the distribution fonction f in all its domain as the sum of a Maxwellian adapted to the boundary (which is not the usual Maxwellian associated with f) and a reminder kinetic part. This Maxwellian is defined such that its ’incoming’ ...