Observations of Ion Density and Temperature around the International Space Station During two Geomagnetic Storms

The International Space Station (ISS) is a low Earth orbit research facility and host to an international crew. Geomagnetic storms cause changes in the Earth’s magnetic field and affect the ion density and temperature in the ionosphere which could pose a hazard to ISS crew. This hazard is measured by the Floating Potential Measurement Unit (FPMU) which measures ion density, ion temperature, and the charge differential of the ISS relative to its surrounding environment. I analyzed data collected by Narrow Sweep Langmuir Probe for two storms in 2015. Ion density and temperature were affected by geomagnetic storms, but the effects were less than those found due to normal orbital conditions

Conceptualising rural-urban dynamics

This paper revisits the work of Richard Cantillon and Francois Quesnay in order to conceptualise the dynamics between rural and urban areas in an economy. Concepts of social surplus and economy as a circular flow are presented in order to highlight the interrelationship between the growth processes in the rural as well as urban areas. The paper concludes by pointing out the significance of the works of Cantillon and Quesnay.Economic growth; Cantillon; Quesnay; Urban; Rural

Economists, listen to Feyerabend

This paper revisits the writings of the philosopher of science, Paul Feyerabend, in order to argue for pluralism in economics education. In particular, the benefits of pluralism, the role of science and the notion of scientific rationality are examined from the perspective of economics.Feyerabend, Economics teaching, Pluralism

On symmetric continuum opinion dynamics

This paper investigates the asymptotic behavior of some common opinion dynamic models in a continuum of agents. We show that as long as the interactions among the agents are symmetric, the distribution of the agents' opinion converges. We also investigate whether convergence occurs in a stronger sense than merely in distribution, namely, whether the opinion of almost every agent converges. We show that while this is not the case in general, it becomes true under plausible assumptions on inter-agent interactions, namely that agents with similar opinions exert a non-negligible pull on each other, or that the interactions are entirely determined by their opinions via a smooth function.Comment: 28 pages, 2 figures, 3 file

Violation of the holographic bulk viscosity bound

Motivated by gauge theory/string theory correspondence, a lower bound on the bulk viscosity of strongly coupled gauge theory plasma was proposed in arXiv:0708.3459. We consider strongly coupled N=4 supersymmetric Yang-Mills plasma compactified on a two-manifold of constant curvature beta. We show that the effective (1+1)-dimensional hydrodynamic description of the system is governed by the bulk viscosity violating the bound of arXiv:0708.3459, once beta<0.Comment: 17 pages, 3 figure

Replica Treatment of the Calogero-Sutherland Model

Employing Forrester-Ha method of Jack polynomials, we derive an integral identity connecting certain N-fold coordinate average of the Calogero-Sutherland model with the n-fold replica integral. Subsequent analytical continuation to non-integer n leads to asymptotic expressions for the (static and dynamic) density-density correlation function of the model as well as the Green's function for an arbitrary coupling constant $\lambda$.Comment: 15 pages, 3 figures, revised version, section 5 corrected, submitted to Nucl.Phys.