We study soft-gluon radiation in top quark decay within the framework of perturbative fragmentation functions. We present results for the b-quark energy distribution, accounting for soft-gluon resummation to next-to-leading logarithmic accuracy in both the MS coefficient function and in the initial condition of the perturbative fragmentation function. The results show a remarkable improvement a...

Recently it has been shown that symmetries emerging in the heavy quark and large recoil energy limit impose various relations on form factors that parametrise the decay of B mesons into light mesons. These symmetries are broken by perturbative effects. In this paper we discuss the structure of heavy-to-light form factors including such effects and compute symmetry-breaking corrections to first ...

We study propagation of dispersion-managed solitons in optical fibers which are modeled by the nonlinear Schrödinger equation with a periodic dispersion coefficient. When the dispersion variations are weak compared to the average dispersion, we develop perturbation series expansions and construct asymptotic solutions at the first and second orders of approximation. Due to a parametric resonance...

We present a generalized mode-coupling theory for a dense binary fluid mixture. The theory is used to calculate molecular-scale renormalizations to the stress-tensor autocorrelation function (STAF) and to the long-wavelength zero-frequency shear viscosity. As in the case of a dense simple fluid, we find that the STAF appears to decay as t over an intermediate range of time. The coefficient of t...

More than a century ago, Stokes (1819–1903)pointed out that the attenuation of surface waves could be exploited to measure viscosity. This paper provides the link between fluid viscosity and the attenuation of surface waves by invoking the conservation of energy. First we calculate the power loss per unit area due to viscous dissipation. Next we calculate the power loss per unit area as manifes...

Background Phlebotominae sand flies are the main vectors of leishmaniasis and some other diseases. Materials and Methods Using sticky traps, sand flies were collected fortnightly from outdoors and indoors areas of selected sites. Results A total of 2032 specimens (498 in the city and 1534 in the outskirts of Yazd) belonging to 11 species were collected. The activity of sand flies started in...

We contemplate the vitality productive scope and availability issue in remote sensor systems (WSNs). We attempt to find heterogeneous sensors and course information produced to a base station fewer than two clashing goals: minimization of system expense and expansion of system lifetime. We go for fulfilling availability and scope prerequisites and additionally sensor hub and join limit requirem...

the faunistic survey of oribatid mites, between 2008 and 2010, on the outskirts of the city of shiraz led to the discovery of the species banksinoma exobothridialis bayartogtokh of the family thyrisomidae. both the species and the family are new to the iranian fauna.