Regular (nonsingular) space-times are given that describe the formation of a (locally defined) black hole from an initial vacuum region, its quiescence as a static region, and its subsequent evaporation to a vacuum region. The static region is Bardeen-like, supported by finite density and pressures, vanishing rapidly at large radius and behaving as a cosmological constant at small radius. The d...

We present the Hamiltonian, quasilocal energy, and angular momentum for a spacetime region spatially bounded by two timelike surfaces. The results are appplied to the particular case of a spacetime representing an eternal black hole. It is shown that in the case when the boundaries are located in two different wedges of the Kruskal diagram, the Hamiltonian is of the form H = H+−H−, where H+ and...

This paper describes some biodegradation processes originating from the activity of microorganisms in the black crusts of historic buildings. The crusts are mainly composed of gypsum, carbonaceous particles, and polycyclic aromatic hydrocarbons. The slowly dissolving gypsum from black crusts represents a continuous source of sulphur for microbial growth. The sulphate-bonding capacity of the she...

INTRODUCTION Green pigmentation on the palms and soles in patients with hyperbilirubinemia is a rare entity. Eccrine chromhidrosis is an unusual form of green acral pigmentation characterized by the secretion of colored sweat from the eccrine glands. Rarely, eccrine chromhidrosis can mimic an eczematous process leading to misdiagnosis. We report a case of a patient with hyperbilirubinemia who p...

_________________________________ Repulsive interactions between neutrons in compact stellar cores cause luminosity and a steady outflow of hydrogen from stellar surfaces. Neutron repulsion in more massive compact objects made by gravitational collapse produces violent, energetic, cosmological events (quasars, gamma ray bursts, and active galactic centers) that had been attributed to black hole...

Powdery mildew (Sphaerotheca mors-uvae) severely infects young shoots and leaves of black currants (Ribes nigrum) and red currants (R. rubrum) in the Pacific northwestern U.S. Environmentally sound control measures are being sought as alternatives to sulfur or demethylation-inhibiting fungicides. This study examined the effect of mineral oil spray on powdery mildew infection in susceptible blac...

The fluctuating brightness of cosmic X-ray sources, particularly accreting black holes and neutron star systems, has enabled enormous progress in understanding the physics of turbulent accretion flows, the behaviour of matter on the surfaces of neutron stars and improving the evidence for black holes. Most of this progress has been made by analysing and modelling time series data in terms of th...

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. We compute the contribution to the conductivity from holographic Fermi surfaces obtained from probe fermions in an ...

With the help of a generalized Raychaudhuri equation non-expanding null surfaces are studied in an arbitrary dimensional case. The definition and basic properties of non-expanding and isolated horizons known in the literature in the fourand three-dimensional cases are generalized. A local description of the horizon’s geometry is provided. The zeroth law of black-hole thermodynamics is derived. ...

X-ray reflection spectra are an important component in the X-ray spectra of many active galactic nuclei and Galactic black hole candidates. It is likely that reflection takes place from highly ionized surfaces of the accretion disc in some cases. This can lead to strong Comptonization of the emergent iron, and other, absorption and emission features. We present such reflection spectra here, com...