abstract         in the increasing population of the elderly in iran, so far no prospective health studies have been undertaken.   this study was conducted to identify the risk factors of survival time of the elderly of ages above 60 years. material and methods: individuals above 60 years old were recruited in the primary phase of the tehran lipid and glucose study (tlgs) during 1998-2001. they...

In this paper, we consider series-parallel and parallel-series systems with independent subsystems consisting of dependent homogeneous components whose joint lifetimes are modeled by an Archimedean copula. Then, by considering two such systems with different numbers of components within each subsystem, we establish hazard rate and reversed hazard rate orderings between the two system lifetimes,...

data utilized in this study were 6800 records of lambs’ life longevity, and survival rate from 263 sires and 1839 dams collected from 1989 through 2009, from the lori-bakhtiari flock at shooli station in shahrekord. the data were analyzed, using linear and hazard ratio models along with weibul function. these models included such non genetic factors as year and month of birth, sex of lamb, type...