Classically a black hole can absorb but not emit energy. We discuss how this T-asymmetric property of black holes arises in the recently proposed (T-symmetric) microscopic models of black holes based on bound states of D-branes. In these string theory based models, the nonvanishing classical absorption is made possible essentially by the exponentially increasing degeneracy of quantum states wit...

The semiclassical Einstein equations are solved to first order in ǫ = h̄/M for the case of an extreme or nearly extreme Reissner-Nordström black hole perturbed by the vacuum stress-energy of quantized free fields. It is shown that, for realistic fields of spin 0, 1/2, or 1, any zero temperature black hole solution to the equations must have an event horizon at rh < |Q|, with Q the charge of the ...

BACKGROUND Sexual signals, such as bright plumage coloration in passerine birds, reflect individual quality, and testosterone (T) may play a critical role in maintaining signal honesty. Manipulations of T during molt have yielded mixed effects on passerine plumage color, in most cases delaying molt or leading to production of drab plumage. However, the majority of these studies have been conduc...

The quantum string emission by Black Holes is computed in the framework of the “string analogue model” (or thermodynamical approach), which is well suited to combine QFT and string theory in curved backgrounds (particulary here, as black holes and strings posses intrinsic thermal features and temperatures). The QFT-Hawking temperature TH is upper bounded by the string temperature TS in the blac...

A simple, rapid and sensitive method for the estimation of gallic acid has been developed. It is based on reduction of V(V) by gallic acid to V(IV) which forms complex with Eriochrome cyanine-R (ECR) in presence of cetyl trimethyl ammonium bromide (CTAB) resulting in a stable violet colored species. This showed maximum absorption at 580 nm. The calibration line was linear for gallic acid concen...

The change in T 1-hypointense lesion ("black hole") volume is an important marker of pathological progression in multiple sclerosis (MS). Black hole boundaries often have low contrast and are difficult to determine accurately and most (semi-)automated segmentation methods first compute the T 2-hyperintense lesions, which are a superset of the black holes and are typically more distinct, to form...

We propose dual thermodynamics corresponding to black hole mechanics with the identifications E → A/4, S → M , and T ′ → T−1 in Planck units. Here A, M and T are the horizon area, mass and Hawking temperature of a black hole and E, S and T ′ are the energy, entropy and temperature of a corresponding dual quantum system. We show that, for a Schwarzschild black hole, the dual variables formally s...

This study evaluated the correlation between the presence of black extrinsic tooth stains and caries in Brazilian schoolchildren. The target population consisted of 263 children aged 6-12 years. Clinical examinations were performed by four dentists calibrated for the World Health Organization criteria for caries diagnosis. The c(2) test was used to compare the prevalence of caries between group...