We study quantum aspects of the Einstein gravity with one time-like and one space-like Killing vector commuting with each other. The theory is formulated as a SL(2,R)/U(1) nonlinear σ-model coupled to gravity. The quantum analysis of the nonlinear σ-model part, which includes all the dynamical degrees of freedom, can be carried out in a parallel way to ordinary nonlinear σ-models in spite of th...

For estimating reliable exposure-response relations it is necessary that random variation in both the response and the exposure variables be sufficiently small. Variability in cumulative exposures can arise from uncertainties in self-reported work histories from interviews. In most epidemiologic surveys, the information gathered from questionnaires is used without knowing the validity or reprod...

As part of the Periodic X-ray Scheme of the National Coal Board (NCB), a comparison is made between the previous and new films of all miners who were face-workers on the former occasion, five years earlier. This assessment is made by distributing the films randomly to all the NCB readers. This paper compares the rank of coal mined in each colliery with each colliery's percentage prevalence of p...

The stimulated emission of massless bosons by a relativistic and the CGHS black hole are studied for real and complex scalar fields. The radiations induced by one-particle and thermal states are considered and their thermal properties investigated near the horizon. These exhibit both thermal and non-thermal properties for the two black-hole models.

We study the thermodynamics and the small fluctuations of a linear dilaton black hole, in an S-dual version of the near-horizon limit of type IIB NS5 branes. The thermodynamical analysis shows that the black hole is in a Hagedorn phase, with marginal stability. The dynamical analysis confirms that the speed of sound of the dual theory vanishes and that there are no evident instabilities at the ...

The black phosphorus (black-P) crystal is formed of covalently bound layers of phosphorene stacked together by weak van der Waals interactions. An experimental measurement of the exfoliation energy of black-P is not available presently, making theoretical studies the most important source of information for the optimization of phosphorene production. Here, we provide an accurate estimate of the...

In Colombia, coal miner pneumoconiosis is considered a public health problem due to its irreversibility, high cost on diagnosis, and lack of data related to its prevalence in the country. Therefore, a cross-sectional study was carried out in order to determine the prevalence of pneumoconiosis in underground coal mining workers in two regions of Colombia. The results showed a 35.9% prevalence of...

......................................................................................................................................... 3 Acknowledgements ....................................................................................................................... 5

We obtain the BTZ black hole (AdS 3 ×S 3) as a non-dilatonic solution from type 0B string theory. Analyzing the s-wave perturbation around this black hole background, we show that the tachyon is not a propagating mode.

Radiographic changes in 342 Quebec asbestos miners exposed to low levels of asbestos dust for an average period of 20 years were studied. Their estimated cumulative exposure ranged from 7 fibres per cubic centimeter X years (f-y/cc) to 300 f-y/cc. Of these workers, 2.1% showed a small opacity score of 1/0 or more and 2.7% showed pleural changes. No linear relationship could be established betwe...