Melting of antikaon condensate in protoneutron stars

We study the melting of a $K^-$ condensate in hot and neutrino-trapped protoneutron stars. In this connection, we adopt relativistic field theoretical models to describe the hadronic and condensed phases. It is observed that the critical temperature of antikaon condensation is enhanced as baryon density increases. For a fixed baryon density, the critical temperature of antikaon condensation in a protoneutron star is smaller than that of a neutron star. We also exhibit the phase diagram of a protoneutron star with a $K^-$ condensate.Comment: 17 pages including 7 figure

Low-Mass Dileptons at the CERN-SpS: Evidence for Chiral Restoration?

Using a rather complete description of the in-medium $\rho$ spectral function - being constrained by various independent experimental information - we calculate pertinent dilepton production rates from hot and dense hadronic matter. The strong broadening of the $\rho$ resonance entails a reminiscence to perturbative $q\bar q$ annihilation rates in the vicinity of the phase boundary. The application to dilepton observables in Pb(158AGeV)+Au collisions - incorporating recent information on the hadro-chemical composition at CERN-SpS energies - essentially supports the broadening scenario. Possible implications for the nature of chiral symmetry restoration are outlined.Comment: 6 pages ReVTeX including 5 eps-figure

On Some Discrete Distributions and their Applications with Real Life Data

This article reviews some useful discrete models and compares their performance in terms of the high frequency of zeroes, which is observed in many discrete data (e.g., motor crash, earthquake, strike data, etc.). A simulation study is conducted to determine how commonly used discrete models (such as the binomial, Poisson, negative binomial, zero-inflated and zero-truncated models) behave if excess zeroes are present in the data. Results indicate that the negative binomial model and the ZIP model are better able to capture the effect of excess zeroes. Some real-life environmental data are used to illustrate the performance of the proposed models

Some Ridge Regression Estimators and Their Performances

The estimation of ridge parameter is an important problem in the ridge regression method, which is widely used to solve multicollinearity problem. A comprehensive study on 28 different available estimators and five proposed ridge estimators, KB1, KB2, KB3, KB4, and KB5, is provided. A simulation study was conducted and selected estimators were compared. Some of selected ridge estimators performed well compared to the ordinary least square (OLS) estimator and some existing popular ridge estimators. One of the proposed estimators, KB3, performed the best. Numerical examples were given

A Simulation Study on the Size and Power Properties of Some Ridge Regression Tests

Ridge regression techniques have been extensively used to solve the multicollinearity problem for both linear and non-linear regression models since its inception. This paper studied different ridge regression t-type tests of the individual coefficients of a linear regression model. A simulation study has been conducted to evaluate the performance of the proposed tests with respect to their sizes and powers under different settings of the linear regression model. Our simulation results demonstrated that most of the proposed tests have sizes close to the 5% nominal level and all tests except tAKS, tkM2 and tkM9 have considerable gain in powers over the ordinary OLS t-type test. It is also observed that some of the proposed test statistics are performing better than the HK and HKB tests which are proposed some authors

Minimum Enclosing Circle of a Set of Fixed Points and a Mobile Point

Given a set S of n static points and a mobile point p in ℝ2, we study the variations of the smallest circle that encloses S ∪ {p} when p moves along a straight line ℓ. In this work, a complete characterization of the locus of the center of the minimum enclosing circle (MEC) of S ∪ {p}, for p ∈ ℓ, is presented. The locus is a continuous and piecewise differentiable linear function, and each of its differentiable pieces lies either on the edges of the farthest-point Voronoi diagram of S, or on a line segment parallel to the line ℓ. Moreover, the locus has differentiable pieces, which can be computed in linear time, given the farthest-point Voronoi diagram of S

Testing the Population Coefficient of Variation

The coefficient of variation (CV), which is used in many scientific areas, measures the variability of a population relative to its mean and standard deviation. Several methods exist for testing the population CV. This article compares a proposed bootstrap method to existing methods. A simulation study was conducted under both symmetric and skewed distributions to compare the performance of test statistics with respect to empirical size and power. Results indicate that some of the proposed methods are useful and can be recommended to practitioners

Effect of Cultivars and Season on Grafting Success in Sapota under Paschim Midnapur Conditions of West Bengal

Two sets of experiments were carried out during 2007-08 to assess incompatibility of sapota cultivars to softwood grafting, and to find out the best time for softwood grafting, in a private orchard at Jhargram of Paschim Midnapore, West Bengal. Considerable variation in success of softwood grafting among sapota cultivars was observed. Among ten cultivars studied, CO-2 showed highest compatibility with Khirnee rootstock to softwood grafting, followed by Cricket Ball and DSH-2. There was a total failure in graft-take in cultivars CO-1, DSH-1 and Guthi. Softwood grafting success was highest in sapota when carried out on 1stJuly (72%) followed by 15th August (70%), 5th June (62%) and 15th June (56%)

Nucleosynthesis in Neutron Stars Crust

We address the problem of the origin of heavier and super heavy elements in nature. Believing rapid neutron capture process (r-process) is responsible for synthesis of heavy and super heavy elements in the remnants of supernovae explosions and neutron star crusts under extreme conditions, we developed a computer code in order to understand the formation of elements in extreme astrophysical systems. We carried out Nuclear Statistical equilibrium (NSE) as well as static r-process calculations for a wide range of input parameters