Nuclear equation of state at high density and the properties of neutron stars

We discuss the relativistic nuclear equation of state (EOS) using a relativistic transport model in heavy-ion collisions. From the baryon flow for $Au + Au$ systems at SIS to AGS energies and above we find that the strength of the vector potential has to be reduced moderately at high density or at high relative momenta to describe the flow data at 1-10 A GeV. We use the same dynamical model to calculate the nuclear EOS and then employ this to calculate the gross structure of the neutron star considering the core to be composed of neutrons with an admixture of protons, electrons, muons, sigmas and lambdas at zero temperature. We then discuss these gross properties of neutron stars such as maximum mass and radius in contrast to the observational values.Comment: 17 pages, 5 figures, to be published in Phy. Rev.

Evaluation of MegaVoltage Cone Beam CT image quality with an unmodified Elekta Precise Linac and EPID: a feasibility study

In order to increase the accuracy of patient positioning for complex radiotherapy treatments various 3D imaging techniques have been developed. MegaVoltage Cone Beam CT (MVCBCT) can utilise existing hardware to implement a 3D imaging modality to aid patient positioning. MVCBCT has been investigated using an unmodified Elekta Precise linac and 15 iView amorphous silicon electronic portal imaging device (EPID). Two methods of delivery and acquisition have been investigated for imaging an anthropomorphic head phantom and quality assurance phantom. Phantom projections were successfully acquired and CT datasets reconstructed using both acquisition methods. Bone, tissue and air were 20 clearly resolvable in both phantoms even with low dose (22 MU) scans. The feasibility of MegaVoltage Cone beam CT was investigated using a standard linac, amorphous silicon EPID and a combination of a free open source reconstruction toolkit as well as custom in-house software written in Matlab. The resultant image quality has 25 been assessed and presented. Although bone, tissue and air were resolvable 2 in all scans, artifacts are present and scan doses are increased when compared with standard portal imaging. The feasibility of MVCBCT with unmodified Elekta Precise linac and EPID has been considered as well as the identification of possible areas for future development in artifact correction techniques to 30 further improve image quality

Shortcut to Legitimacy : Popularity in Putin’s Russia

Survey evidence suggests that Vladimir Putin’s legitimacy rests on three pillars: domestic order, economic prosperity, and the demonstration of great power status internationally. This is problematic inasmuch as it is based on high degrees of personal popularity which inhibits and contravenes the legal-rational legitimacy of state institutions. This requires continued delivery in all three areas in order to maintain the legitimacy of the regime. This framework allows us better to interpret the 2014 Ukraine crisis as an attempt to shore up support in one ‘pillar’ as performance-based legitimacy recedes

Political Mythmaking and the 2014 Winter Olympics in Sochi : Olympism and the Russian Great Power Myth

The theoretical point of departure of this paper is that the perspective of political myth adds to the understanding of political developments in Russia. The upcoming Olympic Winter Games in Sochi in 2014 are discursively constructed as a manifestation of Russia's return to great power status. In official Russian discourse, there is an encounter between the Russian great power myth and the myth of Olympism, both of which are employed to strengthen the status of Russia and of President Putin personally. Thus, the Olympic values of humanism, internationalism, and progress are merged with Russian great power ideals. But there are also examples where the prevailing myths are turned around to criticise the regime and the Sochi Games. However, the most serious challenge to the Putin regime may stem from the great power myth itself, should the regime prove unable to deliver what it requires