Azimuthal Anisotropy in High Energy Nuclear Collision - An Approach based on Complex Network Analysis

Recently, a complex network based method of Visibility Graph has been applied to confirm the scale-freeness and presence of fractal properties in the process of multiplicity fluctuation. Analysis of data obtained from experiments on hadron-nucleus and nucleus-nucleus interactions results in values of Power-of-Scale-freeness-of-Visibility-Graph-(PSVG) parameter extracted from the visibility graphs. Here, the relativistic nucleus-nucleus interaction data have been analysed to detect azimuthal-anisotropy by extending the Visibility Graph method and extracting the average clustering coefficient, one of the important topological parameters, from the graph. Azimuthal-distributions corresponding to different pseudorapidity-regions around the central-pseudorapidity value are analysed utilising the parameter. Here we attempt to correlate the conventional physical significance of this coefficient with respect to complex-network systems, with some basic notions of particle production phenomenology, like clustering and correlation. Earlier methods for detecting anisotropy in azimuthal distribution, were mostly based on the analysis of statistical fluctuation. In this work, we have attempted to find deterministic information on the anisotropy in azimuthal distribution by means of precise determination of topological parameter from a complex network perspective

Nonstationarity and Nonlinearity in the US Unemployment Rate: A Re-examination

Conventional econometric tests cannot distinguish nonstationarity from nonlinearity because of the joint modeling of unit roots with threshold effects. Caner–Hansen (CH, 2001) provides a new test which for the first time can simultaneously test for both (without any prior assumption of stationarity). Their threshold unit root tests are more powerful than conventional Augmented Dickey-Fuller tests, especially when the true process is nonlinear. They look at unemployment among adult males, and find contrary to many previous studies, that it is a “stationary nonlinear threshold process”. This paper attempts to re-examine and reconfirm the CH methodology by using unemployment in the civilian labor force. We extend the data up to December 2004, to see if the results hold up to the recent turbulent times, when unemployment changed dramatically from 3.9 % (1999) to 6.2 % (2003). Our results support the premise that US unemployment is a stationary threshold autoregressive process.

Instability in a Market Economy and the Harrod Growth Model

What is very often overlooked in the literature is that the Harrod’s Post- Keynesian growth model is more to do with the problem of instability in a market economy which is caused by the role of expectations of the investors. The neoclassical model of growth due to Solow achieves stability not due to its assumption of smooth twice differentiable production function but assuming away the role of uncertainty

Post-Keynesian Models of Economic Growth: Open Systems

The closed systems nature of neoclassical models of economic growth – guaranteeing automatic equality between planned savings and investment which, in turn, ensures stability of such models – is achieved by assuming away the existence of uncertainty inherent in economic systems. Once the role of Keynesian uncertainty is acknowledged, the assumption of automatic equality between ex-post savings and ex-ante investment becomes untenable. This paper attempts to show that once this possibility of planned savings and investment inequality is incorporated in an otherwise essentially neoclassical model of economic growth, its closed system nature disappears and the model metamorphoses itself into an open system

Comparative Multi Fractal De-trended Fluctuation Analysis of heavy ion interactions at a few GeV to a few hundred GeV

We have studied the multifractality of pion emission process in 16O-AgBr interactions at 2.1AGeV & 60AGeV, 12CAgBr &24Mg-AgBr interactions at 4.5AGeV and 32S-AgBr interactions at 200AGeV using Multifractal Detrended Fluctuation Analysis (MFDFA) method which is capable of extracting the actual multifractal property filtering out the average trend of fluctuation. The analysis revels that the pseudo rapidity distribution of the shower particles is multifractal in nature for all the interactions i.e. pion production mechanism has in built multi-scale self-similarity property. We have employed MFDFA method for randomly generated events for 32S-AgBr interactions at 200 AGeV. Comparison of expt. results with those obtained from randomly generated data set reveals that the source of multifractality in our data is the presence of long range correlation. Comparing the results obtained from different interactions, it may be concluded that strength of multifractality decreases with projectile mass for same projectile energy and for a particular projectile it increases with energy. The values of ordinary Hurst exponent suggest that there is long range correlation present in our data for all the interactions