Background: Total bone mass acquired during childhood is known to be the most important determinant and base of lifelong skeletal health. The present study investigated the prevalence of low bone mass for chronological age (LBM) in lumbar and femoral areas of leukemic children in the south of Iran and evaluated the association of anthropometric, clinical and laboratory data of these children ...

BACKGROUND The density of breast tissue on a mammogram is a strong predictor of breast cancer risk and may reflect cumulative estrogen effect on breast tissue. Endogenous and exogenous estrogen exposure increases the risk of estrogen receptor (ER)-positive breast cancer. We determined if mammographic density is associated more strongly with ER-positive breast cancer than with ER-negative breast...

We propose a 4-dimensional Kaluza-Klein approach to general relativity in the (2,2)-splitting of space-time using the double null gauge. The associated Lagrangian density, implemented with the auxiliary equations associated with the double null gauge, is equivalent to the Einstein-Hilbert Lagrangian density, since it yields the same field equations as the E-H Lagrangian density does. It is desc...

Dark matter modeled as a classical scalar field that interacts only with gravity and with itself by a potential that is close to quartic at large field values and approaches a quadratic form when the field is small would be gravitationally produced by inflation and, at the present epoch, could act like an ideal fluid with pressure that is a function only of the mass density. This could have obs...

We derive via diagrammatic perturbation theory the scaling behavior of the condensate and superfluid mass density of a dilute Bose gas just below the condensation temperature, T(c). Sufficiently below T(c) particle excitations are described by mean field (Bogoliubov). Near T(c), however, mean field fails, and the system undergoes a second order phase transition, rather than first order as predi...

We study the cosmological gravitino production in gauge mediated supersymmetry breaking models, while properly taking into account the existence of the messenger mass scale. It is found that for sizable parameter range of the model the messenger sector contribution leads to more stringent upper bound on the reheat temperature obtained from the condition that the universe should not be overclose...

In this paper we use the semi-analytical approach to analyze gravitational lensing of remote objects (quasars) by dark halos in various cosmologies in order to determine the sensitivity of the predictions for probabilities of splitting-angles of multiple images to the input assumptions regarding halo properties and cosmological model. All models are variants of the cold dark matter scenario and...

I demonstrate that, under certain circumstances, regions of negative energy density can undergo gravitational collapse into a black hole. The resultant exterior black hole spacetimes necessarily have negative mass and non-trivial topology. A full theory of quantum gravity, in which topologychanging processes take place, could give rise to such spacetimes. 2 Internet: [email protected] Th...