4,968 research outputs found
Ring diagram analysis of near-surface flows in the Sun
Ring diagram analysis of solar oscillation power spectra obtained from MDI
data is carried out to study the velocity fields in the outer part of the solar
convection zone. The three dimensional power spectra are fitted to a model
which has a Lorentzian profile in frequency and which includes the advection of
the wave front by horizontal flows, to obtain the two components of the
sub-surface flows as a function of the horizontal wave number and radial order
of the oscillation modes. This information is then inverted using OLA and RLS
methods to infer the variation in horizontal flow velocity with depth. The
average rotation velocity at different latitudes obtained by this technique
agrees reasonably with helioseismic estimates made using frequency splitting
data. The shear layer just below the solar surface appears to consist of two
parts with the outer part up to a depth of 4 Mm, where the velocity gradient
does not show any reversal up to a latitude of 60 degrees. In the deeper part
the velocity gradient shows reversal in sign around a latitude of 55 degrees.
The zonal flow velocities inferred in the outermost layers appears to be
similar to those obtained by other measurements. A meridional flow from equator
polewards is found. It has a maximum amplitude of about 30 m/s near the surface
and the amplitude is nearly constant in the outer shear layer.Comment: aastex, 12 figures, to appear in Ap.
Born-Infeld Chern-Simons Theory: Hamiltonian Embedding, Duality and Bosonization
In this paper we study in detail the equivalence of the recently introduced
Born-Infeld self dual model to the Abelian Born-Infeld-Chern-Simons model in
2+1 dimensions. We first apply the improved Batalin, Fradkin and Tyutin scheme,
to embed the Born-Infeld Self dual model to a gauge system and show that the
embedded model is equivalent to Abelian Born-Infeld-Chern-Simons theory. Next,
using Buscher's duality procedure, we demonstrate this equivalence in a
covariant Lagrangian formulation and also derive the mapping between the
n-point correlators of the (dual) field strength in Born-Infeld Chern-Simons
theory and of basic field in Born-Infeld Self dual model. Using this
equivalence, the bosonization of a massive Dirac theory with a non-polynomial
Thirring type current-current coupling, to leading order in (inverse) fermion
mass is also discussed. We also re-derive it using a master Lagrangian.
Finally, the operator equivalence between the fermionic current and (dual)
field strength of Born-Infeld Chern-Simons theory is deduced at the level of
correlators and using this the current-current commutators are obtained.Comment: 27 pages, One reference added, minor changes in presentation and
typos corrected. To appear in Nucl. Phys.
Seismic investigation of the solar structure using GONG frequencies
Using the recently obtained GONG frequencies, we investigate the properties
of the solar interior by constructing solar models with various input physics
like opacities, equation of state, nuclear reaction rates etc. The differential
asymptotic inversion technique is then used to infer the relative difference in
sound speed between the Sun and solar models. Here we apply these results to
test equation of state and different formulation for calculating the convective
flux.Comment: Latex, 2 pages, 3 figures, To appear in the IAU Symp. # 181:
"Sounding solar and stellar interiors", eds. F.X. Schmider & J. Provos
Azimuthal correlations of D-mesons in + and +Pb collisions at LHC energies
We study the correlations of D mesons produced in + and +Pb
collisions. These are found to be sensitive to the effects of the cold nuclear
medium and the transverse momentum () regions we are looking into. In
order to put this on a quantitative footing, as a first step we analyse the
azimuthal correlations of D meson-charged hadron(Dh), and then predict the same
for D meson -anti D meson () pairs in + and +Pb
collisions with strong coupling at leading order ()
and next to leading order () which includes space-time
evolution (in both systems), as well cold nuclear matter effects (in +Pb).
This also sets the stage and baseline for the identification and study of
medium modification of azimuthal correlations in relativistic collision of
heavy nuclei at the Large Hadron Collider.Comment: 12 pages, 4 figure
Building Quality Teamwork to Achieve Excellence in Business Organizations
Business organizations are continuously and rapidly expanding. Gone are the days when only individual\u27s talent and abilities that were counted upon. Business organizations today have found out that the key factor of achieving more and better results at work is when individuals of diverse abilities are formed into a team. This ability to work as part of a team is one of the most imperative skills today. Business organizations are looking for individuals who can not only furnish their own ideas but also who would like to create and develop projects and plans with equally talented people. This paper emphasizes the need and importance of working in a team based organizational setting and also focuses on the five stages of development o a team in the organization
Two site self consistent method for front propagation in reaction-diffusion system
We study front propagation in the reaction diffusion process
on one dimensional lattice with hard core interaction
between the particles. We propose a two site self consistent method (TSSCM) to
make analytic estimates for the front velocity and are in excellent agreement
with the simulation results for all parameter regimes. We expect that the
simplicity of the method will allow one to use this technique for estimating
the front velocity in other reaction diffusion processes as well.Comment: 6 figure
Economic value of water in agriculture: comparative analysis of a water-scarce and water-rich region in India
Water productivityEconomic evaluationCrop productionIrrigated farmingWater costsWellsLivestockMilk production
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