The thyroid hormone receptor (TR) and the retinoic acid receptor (RAR) induce gene expression in the presence of specific ligand and repress transcription in the absence of hormone. This repression is mediated by an active silencing mechanism rather then by interference with DNA binding activators. V-erbA, a variant form of TR which is unable to bind hormone, represents a constitutive repressor...

in this paper, we study different methods of solving joint redundancy-availability optimization for series-parallel systems with multi-state components. we analyzed various effective factors on system availability in order to determine the optimum number and version of components in each sub-system and consider the effects of improving failure rates of each component in each sub-system and impr...