11,671 research outputs found
An exact master equation for the system-reservoir dynamics under the strong coupling regime and non-Markovian dynamics
In this paper we present a method to derive an exact master equation for a
bosonic system coupled to a set of other bosonic systems, which plays the role
of the reservoir, under the strong coupling regime, i.e., without resorting to
either the rotating-wave or secular approximations. Working with phase-space
distribution functions, we verify that the dynamics are separated in the
evolution of its center, which follows classical mechanics, and its shape,
which becomes distorted. This is the generalization of a result by Glauber, who
stated that coherent states remain coherent under certain circumstances,
specifically when the rotating-wave approximation and a zero-temperature
reservoir are used. We show that the counter-rotating terms generate
fluctuations that distort the vacuum state, much the same as thermal
fluctuations.Finally, we discuss conditions for non-Markovian dynamics
Electrostatic self-force in (2+1)-dimensional cosmological gravity
Point sources in (2+1)-dimensional gravity are conical singularities that
modify the global curvature of the space giving rise to self-interaction
effects on classical fields. In this work we study the electrostatic
self-interaction of a point charge in the presence of point masses in
(2+1)-dimensional gravity with a cosmological constant.Comment: 9 pages, Late
Dilute-phase pneumatic conveying of polystyrene particles: pressure drop curve and particle distribution over the pipe cross-section
During the pneumatic conveying of plastic pellets, it has been observed that materials with similar physical characteristics may develop a substantial difference in pressure drop. In this work, the pressure drop in a particle-laden 2.7 meter long horizontal channel with circular cross-section is presented from an experimental perspective. Experiments are carried out for cylindrical polystyrene beads with an average diameter of 3.2 mm and mass loadings of 0.06 to 0.11 (kg particles/kg gas). The air mass flow rate was studied in the range from 0.085 kg/s to 0.170 kg/s. The pressure drop curve is shown as a function of air velocity and particle load. Response surface methodology showed high statistical significance for air velocity, particle load and their cross-relation.8188Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Teor de nitrogênio em sementes de Araucaria angustifolia.
Edição dos resumos do 18º Congresso Brasileiro de Sementes, 2013, Florianópolis
Resíduo micropulverizado da moagem a seco de milho não afeta biodisponibilidade de zinco em ratos.
Trabalho apresentado no XV Congresso Latinoamericano de Nutricion e XVI Jornadas de la Sociedad Chilena de Nutrición, 2009, Santiago do Chile
Nematic liquid crystal dynamics under applied electric fields
In this paper we investigate the dynamics of liquid crystal textures in a
two-dimensional nematic under applied electric fields, using numerical
simulations performed using a publicly available LIquid CRystal Algorithm
(LICRA) developed by the authors. We consider both positive and negative
dielectric anisotropies and two different possibilities for the orientation of
the electric field (parallel and perpendicular to the two-dimensional lattice).
We determine the effect of an applied electric field pulse on the evolution of
the characteristic length scale and other properties of the liquid crystal
texture network. In particular, we show that different types of defects are
produced after the electric field is switched on, depending on the orientation
of the electric field and the sign of the dielectric anisotropy.Comment: 7 pages, 12 figure
Response of the parasitoid Telenomus podisi to induced volatiles from soybean damaged by stink bug herbivory and oviposition.
Egg parasitoids have a short time frame in which their host eggs are suitable for parasitism, and in several systems these parasitoids respond to plant volatiles induced by oviposition on the plant (either in isolation or in combination with feeding damage) as a means of finding suitable hosts. It is known that the parasitoid of pentatomid eggs Telenomus podisi responds to damage done to soybeans by female Euschistus heros, its preferred host. ln this study our aim was to determine the type of E. heros damage to soybean (herbivory, oviposition or a combination of both) necessary for attraction of T. podisi. ln a Y-tube olfactometer the parasitoid has shown to respond to the undamaged plant over clcan air and herbivory-damaged plants over undamaged plants. However, the parasitoids did not respond to the treatments wherc oviposition occurred, either in isolation or in combination with herbivory. Analysis of volatile blends revealed that herbivory plus oviposition damage to soybean induced a volatile blend different to those induced when herbivory or oviposition occurred separately. These results, along with other results from this system, suggest that T. podisi uses plant volatile cues associated with female E. heros damage in order to be present when E. heros lays its eggs, and thus ensure its resource is optimal for parasitism
The pasta phase within density dependent hadronic models
In the present paper we investigate the onset of the pasta phase with
different parametrisations of the density dependent hadronic model and compare
the results with one of the usual parametrisation of the non-linear Walecka
model. The influence of the scalar-isovector virtual delta meson is shown. At
zero temperature two different methods are used, one based on coexistent phases
and the other on the Thomas-Fermi approximation. At finite temperature only the
coexistence phases method is used. npe matter with fixed proton fractions and
in beta-equilibrium are studied. We compare our results with restrictions
imposed on the the values of the density and pressure at the inner edge of the
crust, obtained from observations of the Vela pulsar and recent isospin
diffusion data from heavy-ion reactions, and with predictions from spinodal
calculations.Comment: 15 pages, 11 figures and 7 table
The self-energy of a charged particle in the presence of a topological defect distribution
In this work we study a charged particle in the presence of both a continuous
distribution of disclinations and a continuous distribution of edge
dislocations in the framework of the geometrical theory of defects. We obtain
the self-energy for a single charge both in the internal and external regions
of either distribution. For both distributions the result outside the defect
distribution is the self-energy that a single charge experiments in the
presence of a single defect.Comment: 12 pages, Revtex4, two figures,to appear in Int. Joun. Mod. Phys.
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