On Rigidity of 3d Asymptotic Symmetry Algebras

We study rigidity and stability of infinite dimensional algebras which are not subject to the Hochschild-Serre factorization theorem. In particular, we consider algebras appearing as asymptotic symmetries of three dimensional spacetimes, the BMS3, u(1) Kac-Moody and Virasoro algebras. We construct and classify the family of algebras which appear as deformations of BMS3, u(1) Kac-Moody and their central extensions by direct computations and also by cohomological analysis. The Virasoro algebra appears as a specific member in this family of rigid algebras; for this case stabilization procedure is inverse of the In\"on\"u-Wigner contraction relating Virasoro to BMS3 algebra. We comment on the physical meaning of deformation and stabilization of these algebras and relevance of the family of rigid algebras we obtainComment: 50 pages, one figure and two tables; v2: minor improvements, references adde

Evaluating the effects of climate on weathering processes of rocks based on Peltier models in Kermanshah province

Weathering is a result of physical, chemical and biological factors, all of which affect the rocks but do not cause Material Handling. The existence of pores and crevices and cracks in the rocks expose the rocks to physical and chemical attack, gradual wracking and being weathered. This study has been based on Louis Peltier’s models in which two mean annual temperature and precipitation variables are used. Peltier identified seven models using these two variables which can describe different types of weathering phenomena. Among these models, two models related to weathering regimes and morphogenetic regimes were evaluated in case of Kermanshah province and the regimes related to each station were determined from the related diagrams. Climate data such as mean annual temperature and precipitation and eight synoptic stations which had appropriate data and statistical length were taken from meteorological organization and then were recorded in a database in GIS environment for studying and zoning of the weathering status and geomorphological regions in Kermanshah. Then, the regimes relating to each station were determined from Peltier models after evaluation of temperature and precipitation processes in the study area which were recorded in the database after giving weighted value to them and then the related maps were generated in ARC map environment. The obtained results showed that most parts of Kermanshah province are semi-arid regions. Chemical weathering along with glacial action to moderate chemical weathering take place in in Kermanshah province in terms of weathering status.Keywords: Weathering regimes, Peltier model, morphogenetic regions, Kermanshah

Statistics of the Number of Zero Crossings : from Random Polynomials to Diffusion Equation

We consider a class of real random polynomials, indexed by an integer d, of large degree n and focus on the number of real roots of such random polynomials. The probability that such polynomials have no real root in the interval [0,1] decays as a power law n^{-\theta(d)} where \theta(d)>0 is the exponent associated to the decay of the persistence probability for the diffusion equation with random initial conditions in space dimension d. For n even, the probability that such polynomials have no root on the full real axis decays as n^{-2(\theta(d) + \theta(2))}. For d=1, this connection allows for a physical realization of real random polynomials. We further show that the probability that such polynomials have exactly k real roots in [0,1] has an unusual scaling form given by n^{-\tilde \phi(k/\log n)} where \tilde \phi(x) is a universal large deviation function.Comment: 4 pages, 3 figures. Minor changes. Accepted version in Phys. Rev. Let

Accelerating Universe in Terms of Hankel Function Index

In this paper, $F(\nu)$ cosmology is proposed for the accelerating universe with asymptotic de Sitter expansion in terms of Hankel function index $\nu$. To some extent, both the initial expansion during early inflation and the current accelerated expansion can be studied with a vacuum cosmic fluid i.e. $\Lambda$ in the pure de Sitter phase. Observational data further support the notion of a quasi-vacuum fluid, rather than a pure vacuum, contributing to the quasi-de Sitter acceleration in both the early and late universe. By examining the asymptotic expansion of the Henkel function as an approximate solution of the Mukhanov-Sasaki equation, we seek a more detailed study of quasi-de Sitter solutions in cosmology containing vacuum-like fluid.Comment: 11 pages, 2 table

Species identification reveals mislabeling of important fish products in Iran by DNA barcoding

This study reports on the molecular identification of fish species from processed products which had a priori been classified as belonging to 5 important species in Iran for human consumption. DNA barcoding using direct sequencing of an approximately 650bp of mitochondrial Cytochrome oxidase subunit I (COI) gene revealed incorrect labeling of Narrow-barred Spanish mackerel samples. High occurrence of fraudulent fishery products, if left unchecked, can pose a negative impact on the economy. This investigation adds further concern on the trading of processed fish products in Iran from both health and conservation points of view