8,736 research outputs found
Role of Dream in Kui-Culture
The dream is a state of mind while asleep. It is
a reflection of one's thought, imagination and
intuition. Everybody, even a blind can have
dreams. Dreams have influenced the lives of
people since the beginning across civilisations
in myriad ways.
It is now part of the legend that Queen
Mayadevi of King Sudhodan had a dream that
an elephant is entering her body. To explain
the dream the wise men of the royal court were
consulted. The opinion was the queen would
beget a son who has qualities of a superman,
who can become a "chakravarti" or an ascetic.
The Child became the Buddha, the enlightened
one. Similarly, the Queen of Julius Caesar had
a dram that the statue of Caesar in the market
place is bleeding and she apprehended a
danger to the life of her husband. It was for the
dream; she pleaded Caesar not to go to the party
by his friends in which Caesar was ultimately
stabbed to death. In both the instances, the
dreams were indicative of the coming events
Dynamics of Magnetized Bulk Viscous Strings in Brans-Dicke Gravity
We explore locally rotationally symmetric Bianchi I universe in Brans-Dicke
gravity with self-interacting potential by using charged viscous cosmological
string fluid. We use a relationship between the shear and expansion scalars and
also take the power law for scalar field as well as self-interacting potential.
It is found that the resulting universe model maintains its anisotropic nature
at all times due to the proportionality relationship between expansion and
shear scalars. The physical implications of this model are discussed by using
different parameters and their graphs. We conclude that this model corresponds
to an accelerated expanding universe for particular values of the parameters.Comment: 17 pages, 6 figure
Highly Excited Core Resonances in Photoionization of Fe XVII : Implications for Plasma Opacities
A comprehensive study of high-accuracy photoionization cross sections is
carried out using the relativistic Breit-Pauli R-matrix (BPRM) method for (hnu
+ Fe XVII --> Fe XVIII + e). Owing to its importance in high-temperature
plasmas the calculations cover a large energy range, particularly the myriad
photoexciation-of-core (PEC) resonances including the n = 3 levels not
heretofore considered. The calculations employ a close coupling wave function
expansion of 60 levels of the core ion Fe XVIII ranging over a wide energy
range of nearly 900 eV between the n = 2 and n = 3 levels. Strong coupling
effects due to dipole transition arrays 2p^5 --> 2p^4 (3s,3d) manifest
themselves as large PEC resonances throughout this range, and enhance the
effective photoionization cross sections orders of magnitude above the
background. Comparisons with the erstwhile Opacity Project (OP) and other
previous calculations shows that the currently available cross sections
considerably underestimate the bound-free cross sections. A
level-identification scheme is used for spectroscopic designation of the 454
bound fine structure levels of Fe XVII. Level-specific photoionization cross
sections are computed for all levels. In addition, partial cross sections for
leaving the core ion Fe XVII in the ground state are also obtained. These
results should be relevant to modeling of astrophysical and laboratory plasma
sources requiring (i) photoionization rates, (ii) extensive
non-local-thermodynamic-equilibrium models, (iii) total unified electron-ion
recombination rates including radiative and dielectronic recombination, and
(iv) plasma opacities. We particularly examine PEC and non-PEC resonance
strengths and emphasize their expanded role to incorporate inner-shell
excitations for improved opacities, as shown by the computed monochromatic
opacity of Fe XVII.Comment: 12 pages, 5 figures, Physical Review A (in press
Higher Dimensional Dust Cosmological Implications of a Decay Law for Term : Expressions for Some Observable Quantities
In this paper we have considered the multidimensional cosmological
implications of a decay law for term that is proportional to , where is a constant and is the scale factor
of RW-space time. We discuss the cosmological consequences of a model for the
vanishing pressure for the case . It has been observed that such models
are compatible with the result of recent observations and cosmological term
gradually reduces as the universe expands. In this model
varies as the inverse square of time, which matches its natural units. The
proper distance, the luminosity distance-redshift, the angular diameter
distance-redshift, and look back time-redshift for the model are presented in
the frame work of higher dimensional space time. The model of the Freese {\it
et al.} ({\it Nucl. Phys. B} {\bf 287}, 797 (1987)) for is retrieved for
the particular choice of and also Einstein-de Sitter model is obtained
for . This work has thus generalized to higher dimensions the
well-know result in four dimensional space time. It is found that there may be
significant difference in principle at least, from the analogous situation in
four dimensional space time.Comment: 10 pages, no figure, to be appear in IJMP
Bianchi Type-II String Cosmological Models in Normal Gauge for Lyra's Manifold with Constant Deceleration Parameter
The present study deals with a spatially homogeneous and anisotropic
Bianchi-II cosmological models representing massive strings in normal gauge for
Lyra's manifold by applying the variation law for generalized Hubble's
parameter that yields a constant value of deceleration parameter. The variation
law for Hubble's parameter generates two types of solutions for the average
scale factor, one is of power-law type and other is of the exponential form.
Using these two forms, Einstein's modified field equations are solved
separately that correspond to expanding singular and non-singular models of the
universe respectively. The energy-momentum tensor for such string as formulated
by Letelier (1983) is used to construct massive string cosmological models for
which we assume that the expansion () in the model is proportional to
the component of the shear tensor . This
condition leads to , where A, B and C are the metric coefficients
and m is proportionality constant. Our models are in accelerating phase which
is consistent to the recent observations. It has been found that the
displacement vector behaves like cosmological term in the
normal gauge treatment and the solutions are consistent with recent
observations of SNe Ia. It has been found that massive strings dominate in the
decelerating universe whereas strings dominate in the accelerating universe.
Some physical and geometric behaviour of these models are also discussed.Comment: 24 pages, 10 figure
X-ray He-like ions diagnostics: New Computations for Photoionized Plasmas: I. preliminary considerations
Using the new version of the photoionization code Titan designed for
plane-parallel photoionized thick hot media, which is unprecedented from the
point of view of line transfer, we have undertaken a study of the influence of
different parameters on the He-like and H-like emission of a medium
photoionized by an X-ray source. We explain why in modelling the emitting
medium it is important to solve in a self-consistent way the thermal and
ionization equilibria and to take into account the interconnection between the
different ions. We give the equivalent widths of the sum of the He-like
triplets and the triplet intensity ratios and , for the most important
He-like ions, for a range of density, column density, and ionization parameter,
in the case of constant density media. We show that the line intensities from a
given ion can be accounted for, either by small values of both the column
density and of the ionization parameter, or by large values of both quantities,
and it is necessary to take into account several ions to disentangle these
possibilities. We show also that a "pure recombination spectrum" almost never
exists in a photoionized medium: either it is thin, and resonance lines are
formed by radiative excitation, or it is thick, and free-bound absorption
destroys the resonance photons as they undergo resonant diffusion.Comment: 19 pages, 14 figures, accepted in A &
Bianchi Type I Magnetofluid Cosmological Models with Variable Cosmological Constant Revisited
The behaviour of magnetic field in anisotropic Bianchi type I cosmological
model for bulk viscous distribution is investigated. The distribution consists
of an electrically neutral viscous fluid with an infinite electrical
conductivity. It is assumed that the component of shear tensor
is proportional to expansion () and the coefficient of
bulk viscosity is assumed to be a power function of mass density. Some physical
and geometrical aspects of the models are also discussed in presence and also
in absence of the magnetic field.Comment: 13 page
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