The variable-r model provides demographers with a way to explore the contributions of demographic components (fertility, mortality, migration) changes in populations’ age structures. However, traditional methods require extremely long mortali

We have simulated the effect of the diversity of the late expressed genes in the genetic pool of population on the phenotypes of individuals in the late ages. Using Penna model based on the Monte Carlo method we have obtained for the oldest fractions of populations lower mortality rates than predicted by the exponential Gompertz function. Such deviations from the expected exponential increase o...

A popular interpretation of recent microlensing studies of the line of sight towards the Large Magellanic Cloud invokes a population of old white dwarf stars in the Galactic halo. Below I review the basic properties of old white dwarf stars and the ongoing efforts to detect this population directly.

We report the results of a coherent study of three chemically anomalous metal-poor ([Fe/H] ∼ –2) stars. These objects exhibit unusually low abundances of Mg, Si, Ca (α-elements) and Sr, Y, and Ba (neutron-capture elements). Our analyses confirm and expand upon earlier reports of atypical abundances in BD+80 245, G4-36, and CS22966-043. We also find that the latter two stars exhibit enhanced abu...

Abstract This article examines the health status of population in Bulgaria at age 65 by gender during period 2006-2014. The is examined some most frequently used demographic indicators, namely life expectancy, based on mortality data and healthy years mortality, expectancy self-perceived health. main results show that despite observed increase it lowest compared to other European countries. sha...