194 research outputs found
Phantom Mimicry on the Normal Branch of a DGP-inspired Braneworld Scenario with Curvature Effect
It has been shown recently that phantom-like effect can be realized on the
normal branch of the DGP setup without introduction of any phantom matter
neither in the bulk nor on the brane and therefore without violation of the
null energy condition. It has been shown also that inclusion of the
Gauss-Bonnet term in the bulk action modifies this picture via curvature
effects. Here, based on the Lue-Starkman conjecture on the dynamical screening
of the brane cosmological constant in the DGP setup, we extend this proposal to
a general DGP-inspired model that stringy effects in the
ultra-violet sector of the theory are taken into account by inclusion of the
Gauss-Bonnet term in the bulk action. We study cosmological dynamics of this
setup, especially its phantom-like behavior and possible crossing of the
phantom divide line especially with a non-minimally coupled quintessence field
on the brane. In this setup, scalar field and curvature quintessence are
treated in a unified framework.Comment: 25 Figures, To appear in MPL
Crossing of the Phantom Divided Barrier with Lorentz Invariance Violating Fields
We study possible crossing of the phantom divided barrier in a Lorentz
invariance violating dark energy model. Lorentz invariance violation which is
achieved by introducing a vector field in the action, incorporates directly in
the dynamics of the scalar field and equation of state. This interesting
feature allows us to study phantom divided barrier crossing in the context of
Lorentz invariance violation. We show that for suitable choice of parameter
space, equation of state can cross phantom divided barrier just by one scalar
field and Lorentz violating vector field controls this crossing.Comment: 14 pages, 4 figures, Revised and References added, Accepted for
Publication in Europhysics Letter
Bandgap Narrowing in Quantum Wires
In this paper we consider two different geometry of quasi one-dimensional
semiconductors and calculate their exchange-correlation induced bandgap
renormalization (BGR) as a function of the electron-hole plasma density and
quantum wire width. Based on different fabrication scheme, we define suitable
external confinement potential and then leading-order GW dynamical screening
approximation is used in the calculation by treating electron-electron Coulomb
interaction and electron-optical phonon interaction. Using a numerical scheme,
screened Coulomb potential, probability of different states, profile of charge
density and the values of the renormalized gap energy are calculated and the
effects of variation of confinement potential width and temperature are
studied.Comment: 17 Pages, 4 Figure
On characterisations of the input to state stability properties for conformable fractional order bilinear systems
This paper proposes for the first time the theoretical requirements that a fractional-order bilinear system with conformable derivative has to fulfil in order to satisfy different input-to-state stability (ISS) properties. Variants of ISS, namely ISS itself, integral ISS, exponential integral ISS, small-gain ISS, and strong integral ISS for the general class of conformable fractional-order bilinear systems are investigated providing a set of necessary and sufficient conditions for their existence and then compared. Finally, the correctness of the obtained theoretical results is verified by numerical example
Effects of fish meal replacement by silkworm pupae on growth, survival and body chemical composition of rainbow trout (Oncorhynchus mykiss)
Silkworm pupae meal is a non-conventional animal protein feedstuff. It is the by-product after the silk thread has been wound off from the cocoon. To investigate the effects of animal protein on growth and survival of rainbow trout (Oncorhynchus mykiss), a sixty-day feeding experiment was conducted. Four replacement levels (0, 5, 10 and 15 percent) of silkworm pupae meal were compared using a completely random design. We used 360 juvenile rainbow trout (average weight 55±3.42g) divided into 4 groups and 3 replications, each containing 30 trout for 60 days. Sampling for nutritional effects was carried out every 10 days and at the end of the experiment, weight gain, feed conversion ratio, specific growth rate, protein and efficiency ratio were compared which showed no significant differences (P>0.05) among the treatments. Total length and survival rate were not significantly affected in the treatment groups. The highest percentage of carcass protein and the lowest percentage of carcass fat belonged to the control treatment. Our findings showed that silkworm pupae meal could replace 15% of fish meal diet in rainbow trout culture
Curvature corrections in DGP brane cosmology
We consider a DGP inspired brane scenario where the action on the brane is
augmented by a function of the Ricci scalar, . The cosmological
implications that such a scenario entails are examined for and shown to
be consistent with a universe expanding with power-law acceleration. It is
shown that two classes of solutions exist for the usual FRW metric and small
Hubble radii. When the Hubble radius becomes larger, we either have a
transition to a fully 5D regime or to a self-inflationary solution which
produces a late accelerated expansion such that the radius becomes a function
of .Comment: 11 pages, 2 figure
Deformed phase space in a two dimensional minisuperspace model
We study the effects of noncommutativity and deformed Heisenberg algebra on
the evolution of a two dimensional minisuperspace cosmological model in
classical and quantum regimes. The phase space variables turn out to correspond
to the scale factor of a flat FRW model with a positive cosmological constant
and a dilatonic field with which the action of the model is augmented. The
exact classical and quantum solutions in commutative and noncommutative cases
are presented. We also obtain some approximate analytical solutions for the
corresponding classical and quantum cosmology in the presence of the deformed
Heisenberg relations between the phase space variables, in the limit where the
minisuperspace variables are small. These results are compared with the
standard commutative and noncommutative cases and similarities and differences
of these solutions are discussed.Comment: 20 pages, 7 figures + 4 contourplots, to appear in CQ
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