Shearfree Condition and dynamical Instability in f(R,T)f(R,T) gravity

The implications of shearfree condition on instability range of anisotropic fluid in $f(R,T)$ are studied in this manuscript. A viable $f(R, T)$ model is chosen to arrive at stability criterion, where $R$ is Ricci scalar and $T$ is the trace of energy momentum tensor. The evolution of spherical star is explored by employing perturbation scheme on modified field equations and contracted Bianchi identities in $f(R, T)$. The effect of imposed shearfree condition on collapse equation and adiabatic index $\Gamma$ is studied in Newtonian and post-Newtonian regimes.Comment: 16 page

Isothermal Plasma Wave Properties of the Schwarzschild de-Sitter Black Hole in a Veselago Medium

In this paper, we study wave properties of isothermal plasma for the Schwarzschild de-Sitter black hole in a Veselago medium. We use ADM 3+1 formalism to formulate general relativistic magnetohydrodynamical (GRMHD) equations for the Schwarzschild de-Sitter spacetime in Rindler coordinates. Further, Fourier analysis of the linearly perturbed GRMHD equations for the rotating (non-magnetized and magnetized) background is taken whose determinant leads to a dispersion relation. We investigate wave properties by using graphical representation of the wave vector, the refractive index, change in refractive index, phase and group velocities. Also, the modes of wave dispersion are explored. The results indicate the existence of the Veselago medium.Comment: 24 pages, 12 figures, accepted for publication in Astrophys. Space Sci. arXiv admin note: text overlap with arXiv:1101.0884 and arxiv:1007.285

Examining the Credibility of Online Political News and Information in the Millennials in Pakistan

This study observed the influence of the credibility factors on the perception of the credibility of political information among the youth. Credibility can be due to the medium through which the information reaches the people; the source of the information; or the information itself. Each of the three factors: medium, source, and message are analyzed separately as an independent variable to observe its influence on the overall credibility of the political content received, as the dependent variable. The key finding is that the majority of them trust that online political content is produced and run by the trustworthy, intelligent and experts. They also appear to believe that online political content is trustworthy, accurate, fair and respectful towards other's privacy. Moreover, it is found that the credibility of online political content is independent of any other credibility factor such as the source, medium, or the content credibility. The number of likes and shares seems to be the biggest criteria of the credibility and trustworthiness of a political content in the eyes of young university students. The findings of the study would allow the experts to convey political information to millennial effectively

Assessment of potential radiological risks due to natural gamma radiations in some selected rock samples using y-ray spectrometry

Abstract One of the sources of radiation risk in dwellings made of rocks is primordial radionuclides. It is imperative to assess the levels of radioactivity due to gamma rays from these materials and consequently to determine the dose rate from these materials. Fourteen samples of rock were collected from various sites of Aurangabad-India and the level of radioactivity and elemental compositions of samples have been measured utilizing y-ray spectroscopy and EDXRF technique. The findings showed that the mean activity concentrations of the 226Ra, 232Th, and 40K were 6.883, 10.841 and 128.616 Bq/kg, lower than the global average values of 35, 30, and 400 Bq/kg. The obtained results were compared with the worldwide average as well as with similar studies. The ratios among the detected radioisotopes in rocks were computed for the spatial distribution of natural radionuclides in the studied area. The radiological risk parameters were estimated and compared with internationally recommended values. The Pearson correlation was used to determine the relationship between the radionuclide concentration and radioactive variables, as well as with the elemental compositions. EDXRF results indicate that SiO2, Al2O3, K2O, CaO, TiO2, Na2O, MgO, P2O5, MnO, and Fe2O3 are the major oxides present in the samples. Moreover, heavy metals such as V, Cr, Co, Ni, Cu, Zn, As, Ba, Cd, Hg, and Pb with varying concentrations were detected. The radiological assessment indicated that the rocks of the study area are radiologically safe and may be used for construction without causing any threat to human health.</jats:p