COVID-19 caused by SARS-CoV-2 have become a global pandemic with serious rate of fatalities. SARS-CoV and MERS-CoV have also caused serious outbreak previously but the intensity was much lower than the ongoing SARS-CoV-2. The main infectivity factor of all the three viruses is the spike glycoprotein. In this study we have examined the intrinsic dynamics of the prefusion, lying state of trimeric S protein of these viruses through Normal Mode Analysis using Anisotropic Network Model. The dynamic modes of the S proteins of the aforementioned viruses were compared by root mean square inner product (RMSIP), spectral overlap and cosine correlation matrix. S proteins show homogenous correlated or anticorrelated motions among their domains but direction of C α atom among the spike proteins show less similarity. SARS-CoV-2 spike shows high vertically upward motion of the receptor binding motif implying its propensity for binding with the receptor even in the lying state. MERS-CoV spike shows unique dynamical motion compared to the other two S protein indicated by low RMSIP, spectral overlap and cosine correlation value. This study will guide in developing common potential inhibitor molecules against closed state of spike protein of these viruses to prevent conformational switching from lying to standing state.

Entropy production from scalar decay in the era of low temperatures after neutrino decoupling will change the ratio of the relic neutrino temperature to the CMB temperature, and, hence, the value of N ef f , the effective number of neutrino species. Such scalar decay is relevant to reheating after thermal inflation, proposed to dilute massive particles, like the moduli and the gravitino, featuring in supersymmetric and string theories. The effect of such entropy production on the relic neutrino temperature ratio is calculated in a semi-analytic manner, and a recent lower bound on this ratio, obtained from the WMAP satellite and 2dF galaxy data, is used to set a lower bound of ∼ 1.5 × 10 −23 Gev on the scalar decay constant, corresponding to a reheating temperature of about 3.3 Mev.

We investigate the effect of B+L−violating anomalous generation of massive right-handed neutrinos on their decoupling, when the righthanded neutrino mass is considerably greater than the right-handed gauge boson masses. Considering normal annihilation channels, the Lee-Weinberg type of calculation, in this case, gives an upper bound of about 700 Gev, which casts doubt on the existence of such a right-handed neutrino mass greater than right-handed gauge boson masses. We examine the possibility that a consideration of anomalous effects related to the SU (2)R gauge group may turn this into a lower bound ∼ 10 2 Tev. PACS number(s) : 18.80.-k, 14.60.St, 11.10.Wx. I. INTRODUCTIONNeutrino oscillation interpretation of recent observations of solar and atmospheric neutrino fluxes, although presenting some inconsistencies, may be taken to strengthen the idea of non-zero neutrino masses. In this situation, in addition to the standard model left-handed neutrinos, the existence and masses of right-handed neutrinos assume topical interest.The contribution of massive neutrinos to the mass-density of the universe 1 allows the setting of a lower bound to such a neutrino mass from the usual cosmological constraints on the age and mass-density of the universe [1,2,3]. The standard calculations consider a neutrino mass less than gauge boson masses.In the present paper, working in a L-R symmetric extension of the standard model [4,5,6], we investigate how the nature of the bound is altered when the right-handed neutrino mass is greater than gauge boson masses.In these L-R symmetric models, the breaking of SU (2) R gauge symmetry is associated with a critical temperature. This may, typically, be of the order of 1-10 Tev [7,8,9], and right-handed electron neutrino masses ≈ 10 Tev have been considered, yielding a left-handed electron neutrino mass ≈ 10 −10 Gev, by a see-saw mechanism [9]. Now, B+L is not conserved in standard electroweak theory due to an anomaly involving the SU (2)

We examine the calculation of density perturbation at large scales in the inflationary scenario. The formula for its magnitude is reviewed from first principles and applied to the original model of extended inflation. Our estimate is an order of magnitude bigger than the earlier ones due to the difference in the time at which the primordial fluctuation is evaluated and to the inclusion of terms neglected earlier in the standard formula for density perturbation.

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