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Bhattacharyya S.,Acharya Prafulla Chandra College
Journal of Physics: Conference Series

Helium-like ions of carbon, aluminum and argon surrounded by strongly coupled plasma have been studied in the framework of ion-sphere potential. A methodology for evaluating two-electron correlated integrals in finite domain have been developed for this purpose. © Published under licence by IOP Publishing Ltd. Source

Das A.,Acharya Prafulla Chandra College
Environmental Modeling and Assessment

Copula functions are useful in constructing multivariate distributions using various marginal distributions and non-linear dependence structures. This paper uses copula functions to construct multivariate distributions with one-sided marginal distributions and copula-based regression to estimate the arsenic exposure in urine using arsenic intake through water and diet as potential covariates in a study in West Bengal, India. As arsenic concentration in urine, water, and diet takes only positive values and negative amount of arsenic concentration in urine, water, and diet are impossibility, one-sided distribution with positive real line support is assumed for these characteristics. Gaussian and Farlie-Gumbel-Morgenstern (FGM) families of copula are considered to capture the non-linear association among these variables. The maximum likelihood method is applied to estimate the parameters of the models. The estimation result suggests that the covariates significantly affect the urinary arsenic exposure, and arsenic intake through diet was a potential contributor of urinary arsenic exposure even when arsenic intake through water was reduced significantly in this arsenic-affected region of West Bengal. © 2014, Springer International Publishing Switzerland. Source

pada Das K.,Indian Statistical Institute | Kundu K.,Acharya Prafulla Chandra College | Chattopadhyay J.,Indian Statistical Institute
Ecological Complexity

A prey-predator model with disease in both the population is proposed and analyzed. Local stability analysis of biologically feasible equilibrium points is worked out with help of ecological as well as disease basic reproduction numbers. We also explain the community composition of ecosystem by basic reproduction numbers. It is shown that the system is globally stable around the interior equilibrium point under certain parametric conditions. Moreover, the system is persistent under some feasible parametric conditions. Our analysis reveals that force of infection and predation rate are the key parameters on the dynamics of the system. Extensive numerical experiments with hypothetical set of parameters are carried out to substantiate our analytical findings. The oscillatory coexistence of the species which is very common in nature is observed for predator disease free system. The introduction of disease in the predator population enhances the extinction of predator population. We also observe that the system will be disease free and all population will persist through proper predational strategies. © 2010 Elsevier B.V. Source

Bhattacharyya S.,Auburn University | Bhattacharyya S.,Acharya Prafulla Chandra College | Saha J.K.,Narula Institute of Technology | Mukherjee P.K.,Ramakrishna Mission Vivekananda University | Mukherjee T.K.,Narula Institute of Technology
Physica Scripta

The effect of spherical confinement on the ground state of helium-like ions (Z = 1-5) and the first four (1Se) excited states for Z = 2-5 have been analyzed in detail by using correlated Hylleraas basis sets within the variational framework. The correlated wave functions used here are consistent with the finite boundary conditions due to spherical confinement. The present energy values and the thermodynamic pressure generated for the confined ions as well as the critical values of the confining radii close to the fragmentation limit can be set as a benchmark for future references. © 2013 The Royal Swedish Academy of Sciences. Source

Saha J.K.,Narula Institute of Technology | Bhattacharyya S.,Acharya Prafulla Chandra College | Mukherjee P.K.,Visva Bharati | Mukherjee P.K.,Ramakrishna Mission Vivekananda University | Mukherjee T.K.,Narula Institute of Technology
Chemical Physics Letters

It is shown for the first time that the analytic form of the wavefunction reveals the real reason behind the dominance of fluorescence decay over autoionization for some doubly excited states of helium without entering into detailed calculation of transition rates. It is remarkable that the angular part of the wavefunction for fluorescence active autoionizing states are same as that of the bound states of that particular symmetry. Subsequently, a criteria has been set up to diagnose the fluorescence active doubly excited states of helium. © 2011 Elsevier B.V. All rights reserved. Source

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