Subhra Bhattacharya

Numerical solution of a singular integro-differential equation

This paper presents a method based on polynomial approximation using Bernstein polynomial basis to obtain approximate numerical solution of a singular integro-differential equation with Cauchy kernel. The numerical results obtained by the present method compares favorably with those obtained by various Galerkin methods earlier in the literature. Also the convergence of the method is established rigorously for the studied integro-differential equation.

An analytic model for interacting dark energy and its observational constraints

The paper deals with a theoretical model for interacting dark energy. The interaction between the cold dark matter (dust) and the dark energy has been assumed to be non-gravitational in nature. Exact analytic cosmological solutions are obtained both for constant and variable equation of state for dark energy. It is found that, for very small value of the coupling parameter (in the interaction term), the model asymptotically extends up to

A Time Since Recovery Model with Varying Rates of Loss of Immunity

\Lambda

f(R) gravity solutions for evolving wormholes

CDM, while the model can enter into the phantom domain asymptotically, if the coupling parameter is not so small. Both the solutions are then analyzed with 194 Supernovae Type Ia data. The best fit parameters are shown with 1

A model of the emergent Universe in inhomogeneous spacetime

\sigma

Evolving cosmic scenario in modified Chaplygin gas with adiabatic matter creation

and 2

A new interacting two-fluid model and its consequences

\sigma

NUMERICAL SOLUTION OF AN INTEGRAL EQUATION ARISING IN THE PROBLEM OF A CRUCIFORM CRACK

confidence intervals. Finally, we have discussed the cosmographic parameters for both the cases.

Cosmic evolution with a general Gaussian type scale factor

For many infectious diseases, immunity wanes over time. The majority of SIRS models assume that this loss of immunity takes place at a constant rate. We study temporary immunity within a SIRS model structure if the rate of loss of immunity can depend on the time since recovery from disease. We determine the conditions under which the endemic steady state becomes unstable and periodic oscillations set in, showing that a fairly rapid change between slow and rapid immunity loss is necessary to produce oscillations.

Numerical Solution of Some Classes of Logarithmically Singular Integral Equations

The scalar–tensor f(R) theory of gravity is considered in the framework of a simple inhomogeneous space-time model. In this research we use the reconstruction technique to look for possible evolving wormhole solutions within viable f(R) gravity formalism. These f(R) models are then constrained so that they are consistent with existing experimental data. Energy conditions related to the matter threading the wormhole are analyzed graphically and are in general found to obey the null energy conditions (NEC) in regions around the throat, while in the limit