Background & Importance: Disc herniation is defined as the prolapsed of material disc into the spinal canal. If the disc fragment is free in spinal canal, it is called sequestration disc fragment. Occasionally, alteration in sequestration disc fragment makes the diagnosis of the disc herniation, challenging. Case Presentation: We reviewed a rare case of the cervical sequestrated disc...

We investigate the nucleosynthesis of heavy elements in the winds ejected by accretion discs formed in neutron star mergers. We compute the element formation in disc outflows from hypermassive neutron star (HMNS) remnants of variable lifetime, including the effect of angular momentum transport in the disc evolution. We employ long-term axisymmetric hydrodynamic disc simulations to model the eje...

We present a critical analysis of the usual interpretation of the multicolour disc model parameters for black hole candidates in terms of the inner radius and temperature of the accretion disc. Using a self-consistent model for the radiative transfer and the vertical temperature structure in a Shakura-Sunyaev disc, we simulate the observed disc spectra, taking into account doppler blurring and ...

We study the effect of corotation resonance on the inertial-acoustic oscillations (pmodes) of black-hole accretion discs. Previous works have shown that for barotropic flows (where the pressure depends only on the density), wave absorption at the corotation resonance can lead to mode growth when the disc vortensity, ζ = κ/(2ΩΣ) (where Ω, κ, Σ are the rotation rate, radial epicyclic frequency an...

We have used narrow emission line data from the new 7C Redshift Survey to investigate correlations between the narrow-line luminosities and the radio properties of radio galaxies and steep-spectrum quasars. The 7C Redshift Survey is a lowfrequency (151 MHz) selected sample with a flux-density limit about 25-times fainter than the 3CRR sample. By combining these samples, we can for the first tim...

We study the efficiency and dynamics of supermassive black hole binary mergers driven by angular momentum loss to small-scale gas discs. Such binaries form after major galaxy mergers, but their fate is unclear since hardening through stellar scattering becomes very inefficient at sub-parsec distances. Gas discs may dominate binary dynamics on these scales, and promote mergers. Using numerical s...

The brakes must be strong enough to stop the vehicle within a minimum distance in an emergency. The driver must have proper control over the vehicle during emergency braking and vehicle must not skid. The brakes must have good antedate characteristics their effectiveness should not decrease with prolonged application and thus it demand that the cooling of the brakes should be very efficient. Fo...

I show that there is a physical limit to the mass of a black hole, above which it cannot grow through luminous accretion of gas, and so cannot appear as a quasar or active galactic nucleus (AGN). The limit is Mmax 5× 1010 M for typical parameters, but can reach Mmax 2.7× 1011 M in extreme cases (e.g. maximal prograde spin). The largest black hole masses so far found are close to but below the l...

Matter accreting onto black holes has long been known to have standing or oscillating shock waves. The post-shock matter puffs up in the form of a torus, which intercepts soft photons from the outer Keplerian disc and inverse Comptonizes to produce hard photons. The post-shock region also produces jets. We study the interaction of both hard photons and soft photons, with onaxis electron-positro...

background & importance: disc herniation is defined as the prolapsed of material disc into the spinal canal. if the disc fragment is free in spinal canal, it is called sequestration disc fragment. occasionally, alteration in sequestration disc fragment makes the diagnosis of the disc herniation, challenging. case presentation: we reviewed a rare case of the cervical sequestrated disc herniation...