Does information entropy play a role in the expansion and acceleration of the Universe?

We propose an interpretation of the expansion and acceleration of the Universe from an information theoretic viewpoint. We obtain the time evolution of the configuration entropy of the mass distribution in a static Universe and show that the process of gravitational instability leads to a rapid dissipation of configuration entropy during the growth of the density fluctuations making such a Universe entropically unfavourable. We find that in an expanding Universe, the configuration entropy rate is governed by the expansion rate of the Universe and the growth rate of density fluctuations. The configuration entropy rate becomes smaller but still remains negative in a matter dominated Universe and eventually becomes zero at some future time in a $\Lambda$ dominated Universe. The configuration entropy may have a connection to the dark energy and possibly plays a driving role in the current accelerating expansion of the Universe leading the Universe to its maximum entropy configuration.Comment: 4 pages, no figures, minor revision, Accepted for publication in MNRAS Letter

Neutron Stars in X-ray Binaries and their Environments

Neutron stars in X-ray binary systems are fascinating objects that display a wide range of timing and spectral phenomena in the X-rays. Not only parameters of the neutron stars, like magnetic field strength and spin period evolve in their active binary phase, the neutron stars also affect the binary systems and their immediate surroundings in many ways. Here we discuss some aspects of the interactions of the neutron stars with their environments that are revelaed from their X-ray emission. We discuss some recent developments involving the process of accretion onto high magnetic field neutron stars: accretion stream structure and formation, shape of pulse profile and its changes with accretion torque. Various recent studies of reprocessing of X-rays in the accretion disk surface, vertical structures of the accretion disk and wind of companion star are also discussed here. The X-ray pulsars among the binary neutron stars provide excellent handle to make accurate measurement of the orbital parameters and thus also evolution of the binray orbits that take place over time scale of a fraction of a million years to tens of millions of years. The orbital period evolution of X-ray binaries have shown them to be rather complex systems. Orbital evolution of X-ray binaries can also be carried out from timing of the X-ray eclipses and there have been some surprising results in that direction, including orbital period glitches in two X-ray binaries and possible detection of the most massive circum-binary planet around a Low Mass X-ray Binary.Comment: Has appeared in Journal of Astrophysics and Astronomy special issue on 'Physics of Neutron Stars and Related Objects', celebrating the 75th birth-year of G. Srinivasa

The Future of the World Trade Organization

The continued difficulties of the World Trade Organization to achieve further multilateral trade liberalization in the Doha Round negotiations have raised questions about its continued relevance. This paper firstly identifies and assesses the key developments in the Doha Round that have contributed to the present stalemate. Secondly, it presents several options that the organization could consider for defining its future work program, given the new realities of global economic engagement, especially the emergence of global production networks. Most importantly, the paper assesses the possibility of including new disciplines covering areas that can help the growth of these drivers of global economic integration. Such an initiative could include three sets of issue: trade facilitation measures, an equitable investment regime, and effective disciplines for curbing non-tariff barriers