Perturbations of the Kerr black hole in the class of axisymmetric artificial black holes. Abstract Artificial black holes (called also acoustic or optical black holes) are the black holes for the linear wave equaion describing the wave propagation in a moving medium. They attracted a considerable interest of physicists who study them to better understand the black holes in general relativity. W...

Perturbations of the Kerr black hole in the class of axisymmetric artificial black holes. Abstract Artificial black holes (called also acoustic or optical black holes) are the black holes for the linear wave equation describing the wave propagation in a moving medium. They attracted a considerable interest of physicists who study them to better understand the black holes in general relativity. ...

Black holes pose a serious problem in the cyclic or oscillating cosmology. It is speculated that, in the cyclic universe with phantom turnarounds, black holes will be torn apart by the phantom energy before turnaround before they can create any problems. In this paper, using the mechanism of the phantom accretion onto black holes, we find that black holes do not disappear before the phantom tur...

We study rotating black holes in Einstein-Yang-Mills-Higgs theory. These black holes emerge from static black holes with monopole hair when a finite horizon angular velocity is imposed. At critical values of the horizon angular velocity and the horizon radius, they bifurcate with embedded Kerr-Newman black holes. The non-Abelian black holes possess an electric dipole moment, but no electric cha...

*Corresponding author and reprint requests Ophthalmology Department, Grampian University Hospitals-NHS Trust, Aberdeen, AB25 2ZN, UK. Phone: 00-44-1224-553217, FAX: 00-44-1224-559231; Email: [email protected] Health Services Research Unit, University of Aberdeen, Aberdeen, AB25 2ZD, UK. Robertson Centre for Biostatistics, University of Glasgow, Glasgow, G12 8QQ, UK. Health Economics Research Un...

Innovative systems and infrastructures such as smart grids, the internet of things, cities, or highways require generally accepted common compatibility standards to enable components of such systems to interoperate. In some cases, various standards are developed by competing standards organizations, often resulting in standards battles. This paper focuses on factors that affect the outcome of t...

Throughout the world, social cause organizations and independent media organizations work together, despite their differences and competition with each other for resources, toward creating civil society. This paper assesses the network dynamics of a system of cooperative competitors in Croatia. The research is framed from the theoretical perspectives of resource dependency, cooperation competit...

Stationary black holes in 5-dimensional Einstein-Maxwell-Chern-Simons theory possess surprising properties. When considering the Chern-Simons coefficient λ as a parameter, two critical values of λ appear: the supergravity value λSG = 1, and the value λ = 2. At λ = 1, supersymmetric black holes with vanishing horizon angular velocity, but finite angular momentum exist. As λ increases beyond λSG ...

We determine the spin of a supermassive black hole in the context of discseismology by comparing newly detected quasi-periodic oscillations (QPOs) of radio emission in the Galactic centre, Sagittarius A* (Sgr A*), as well as infrared and X-ray emissions with those of the Galactic black holes. We find that the spin parameters of black holes in Sgr A* and in Galactic X-ray sources have a unique v...

PURPOSE To better understand hypodense regions (holes) that appear in the retinal nerve fiber layer (RNFL) of frequency-domain optical coherence tomography (fdOCT) scans of patients with glaucoma and glaucoma suspects. METHODS Peripapillary circle (1.7-mm radius) and cube optic disc fdOCT scans were obtained on 208 eyes from 110 patients (57.4 ± 13.2 years) with glaucomatous optic neuropathy ...