843 research outputs found
Pollination ecology of Arrojadoa rhodantha (Gurk) Britton & Rose (Cactaceae) in Petrolina - PE, Brazil.
This work aimed to study the biology and floral visitors ofthis cactus in Petrolina, PE
Thermalization of an anisotropic granular particle
We investigate the dynamics of a needle in a two-dimensional bath composed of
thermalized point particles. Collisions between the needle and points are
inelastic and characterized by a normal restitution coefficient . By
using the Enskog-Boltzmann equation, we obtain analytical expressions for the
translational and rotational granular temperatures of the needle and show that
these are, in general, different from the bath temperature. The translational
temperature always exceeds the rotational one, though the difference decreases
with increasing moment of inertia. The predictions of the theory are in very
good agreement with numerical simulations of the model.Comment: 7 pages, 6 Figures, submitted to PRE. Revised version (Fig1, Fig5 and
Fig6 corrected + minor typos
Leucemia em cĂŁo portador de Leishmaniose visceral. Relato de caso
O artigo nĂŁo apresenta resumo
Electrical conductivity of dispersions: from dry foams to dilute suspensions
We present new data for the electrical conductivity of foams in which the
liquid fraction ranges from two to eighty percent. We compare with a
comprehensive collection of prior data, and we model all results with simple
empirical formul\ae. We achieve a unified description that applies equally to
dry foams and emulsions, where the droplets are highly compressed, as well as
to dilute suspensions of spherical particles, where the particle separation is
large. In the former limit, Lemlich's result is recovered; in the latter limit,
Maxwell's result is recovered
Injected Power Fluctuations in 1D Dissipative Systems
Using fermionic techniques, we compute exactly the large deviation function
(ldf) of the time-integrated injected power in several one-dimensional
dissipative systems of classical spins. The dynamics are T=0 Glauber dynamics
supplemented by an injection mechanism, which is taken as a Poissonian flipping
of one particular spin. We discuss the physical content of the results,
specifically the influence of the rate of the Poisson process on the properties
of the ldf.Comment: 18 pages, 8 figure
Steady state properties of a mean field model of driven inelastic mixtures
We investigate a Maxwell model of inelastic granular mixture under the
influence of a stochastic driving and obtain its steady state properties in the
context of classical kinetic theory. The model is studied analytically by
computing the moments up to the eighth order and approximating the
distributions by means of a Sonine polynomial expansion method. The main
findings concern the existence of two different granular temperatures, one for
each species, and the characterization of the distribution functions, whose
tails are in general more populated than those of an elastic system. These
analytical results are tested against Monte Carlo numerical simulations of the
model and are in general in good agreement. The simulations, however, reveal
the presence of pronounced non-gaussian tails in the case of an infinite
temperature bath, which are not well reproduced by the Sonine method.Comment: 23 pages, 10 figures, submitted for publicatio
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