Probing non-locality of interactions in a Bose-Einstein condensate using solitons.

We consider a Bose-Einstein condensate (BEC) with non-local inter-particle interactions. The local Gross-Pitaevskii (GP) equation is valid for the gas parameter [Formula: see text], but for [Formula: see text], the BEC is described by a modified GP equation (MGPE). We study the exact solutions of the MGPE describing bright and dark solitons.

On noise induced Poincaré-Andronov-Hopf bifurcation.

It has been numerically seen that noise introduces stable well-defined oscillatory state in a system with unstable limit cycles resulting from subcritical Poincaré-Andronov-Hopf (or simply Hopf) bifurcation. This phenomenon is analogous to the well known stochastic resonance in the sense that it effectively converts noise into useful energy. Herein, we clearly explain how noise induced imperfection in the bifurcation is a generic reason for such a phenomenon to occur and provide explicit analytical calculations in order to explain the typical square-root dependence of the oscillations' amplitude on the noise level below a certain threshold value.

Expression of oxidative stress in metastatic retinoblastoma- a comparative study.

Objective: To compare oxidative stress between primary retinoblastoma and retinoblastoma with distant metastasis.

Patients And Methods: Forty consecutive patients presented with primary retinoblastoma and the same number of patients presented with distant metastasis, attending the outpatient department of our hospital between August 2002 and April 2005. All the patients with retinoblastoma underwent a standard metastasis workup and were subsequently categorized into two groups (without metastasis and with metastasis).

A study of twins--in search of an optimal age for delivery.

The question regarding the optimal age of delivery in twins remains unanswered. A prospective observational study was carried out in the gynaecology and obstetrics department of RG Kar Medical College and Hospital, Kolkata during 2008-2009 to arrive at a logical conclusion to this question. The objective of this study was to evaluate the optimal timing of delivery in twins and compare the perinatal outcome in these babies by dividing them into 3 groups: 34 weeks to 35 weeks 6 days, 36 weeks to 37 weeks 6 days and >38 weeks.

Revisiting the Langer-Ambegaokar-McCumber-Halperin theory of resistive transitions in one-dimensional superconductors with exact solutions.

We present an important correction to the Langer-Ambegaokar-McCumber-Halperin theory for the resistive state of a 1D superconductor. We establish that the identification of the saddle on the free energy surface over which Langer and Ambegaokar had claimed the system to move in order to form thermally excited phase slip centres is wrong. With the help of an exact solution we show that the system has to overcome a similar free energy barrier but can actually have vanishing amplitude of the superconducting phase at a point, unlike the Langer-Ambegaokar solution.

Simple solvation potential for coarse-grained models of proteins.

We formulate a simple solvation potential based on a coarsed-grained representation of amino acids with two spheres modeling the C(alpha) atom and an effective side-chain centroid. The potential relies on a new method for estimating the buried area of residues, based on counting the effective number of burying neighbors in a suitable way. This latter quantity shows a good correlation with the buried area of residues computed from all atom crystallographic structures.

Spirals and targets in reaction-diffusion systems.

The existence of spirals and targets is common in reaction diffusion systems of excitable dynamics. I present a multiple scale perturbation analysis to show the existence of all these patterns near a Hopf bifurcation boundary in a Turing type reaction-diffusion system.