Oscillating non-singular relativistic spherical model

A particular choice of the time function in the recently presented spherical solution by Dadhich [1] leads to a singularity free cosmological model which oscillates between two regular states. The energy-stress tensor involves anisotropic pressure and a heat flux term but is consistent with the usual energy conditions (strong, weak and dominant). By choosing the parameters suitably one can make the model consistent with observational data. An interesting feature of the model is that it involves blue shifts as in the quasi steady state model [2] but without violating general relativity.Comment: 6 pages, REVTEX versio

Performance based assessment by introducing active learning in second MBBS students in pharmacology

Background: Currently internal assessment by Maharashtra University Health Science, Nashik is being calculated purely on terminal exams performances, in traditional way which does not reflect active performances by participation in seminar, quiz, problem bases learning, research methodology, individualization of therapy etc.Methods: 35% score in internal assessment is required for eligibility to appear in final exam. On the principle of active participation by pupils while undergoing the training in pharmacology, 83 willing participants from different batches were subjected to the study on their performance scores. Passing criteria was arbitrarily ascertained i.e. either 50% or percentile 60. Percentage was calculated from sum of the scores out of total maximum of different heads, whereas percentile was calculated from sum of the scores out of collective maximum scores.Results: We have observed 73 out of 83 passed on percentage criteria and 74 out of 83 had 60 percentile above scores. The remaining students (10 and 9 respectively) could not reach above said passing criteria due to their non-participation in some of the exercises. Simultaneously using this active participation technique the hidden talent of different abilities can be identified in individual student. Similarly weak areas can also be identified which require improvements.Conclusions: The technique can be useful alternative to final exams in case promotion pattern of assessment is to be applied by institution or if approved, by universities

Non-singular black-holes on the brane

We investigate the possibility of obtaining non-singular black-hole solutions in the brane world model by solving the effective field equations for the induced metric on the brane. The Reissner-Nordstrom solution on the brane was obtained by Dadhich etal by imposing the null energy condition on the 3-brane for a bulk having non zero Weyl curvature. In this work, we relax the condition of vanishing scalar curvature $R$, however, retaining the null condition. We have shown that it is possible to obtain class of static non-singular spherically symmetric brane space-times admitting horizon. We obtain one such class of solution which is a regular version of the Reissner-Nordstrom solution in the standard general relativity.Comment: 8 pages, References added, Version to appear in Int. J. Mod. Phys.

Minimally Invasive Right Anterior Mini-Thoracotomy Aortic Valve Replacement

Since the emergence of small skin incision aortic valve surgery in the late 1990s, minimally invasive aortic valve replacement has now become a viable alternative to standard full sternotomy. The spectrum includes (a) upper hemi sternotomy (T or J shaped), (b) lower partial sternotomy, and (c) right anterior mini-thoracotomy. Potential advantages include a cosmetically appealing scar, decreased post-operative pain and bleeding, shorter ventilation time and hospital stay, and early return to active life. The operative challenges include restricted view and access to the operative field, longer aortic cross-clamp time, and cardiopulmonary bypass time. This necessitates detailed pre-operative imaging, correct selection and assessment of patients, and good communication with perfusionists and anesthetists regarding the plan of each surgery, with a solid back-up plan in case conversion to full sternotomy is required intra-operatively. In recent times, the use of suture less valves and rapid deployment bio prosthesis has dramatically reduced operative time. Here, we describe the work-up, selection criteria, key steps, and potential pitfalls of the right anterior mini-thoracotomy approach for aortic valve replacement

Analysis of a Vaccination Model for Carrier Dependent Infectious Diseases with Environmental Effects

We have proposed and analyzed a nonlinear mathematical model for the spread of carrier dependent infectious diseases in a population with variable size structure including the role of vaccination. It is assumed that the susceptibles become infected by direct contact with infectives and/or by the carrier population present in the environment. The density of carrier population is assumed to be governed by a generalized logistic model and is dependent on environmental and human factors which are conducive to the growth of carrier population. The model is analyzed using stability theory of differential equations and numerical simulation. We have found a threshold condition, in terms of vaccine induced reproduction number R(φ) which is, if less than one, the disease dies out in the absence of carriers provided the vaccine efficacy is high enough, and otherwise the infection is maintained in the population. The model also exhibits backward bifurcation at R(φ) = 1. It is also shown that the spread of an infectious disease increases as the carrier population density increases. In addition, the constant immigration of susceptibles makes the disease more endemic