are alien and blade runner connected

I don't know if they specifically are part of the same world but I think Alien takes place further into the future.  In the director's commentary Ridley Scott said he conceived of a world run by corporations for Alien.  Weyland Utani want the alien for their own interests so they put Ash aboard the Nostromo.  Further, Blade Runner depicts a society ruled by corporations, a metropolis filled with advertisements and logos that pollute the mind's eye and blind Deckard so much he can't see past it or the absurdity of his job as a replicant sent to hunt other replicants, until he confronts the replicant they've branded as the greatest threat who ends up saving his life on the ledge and he finally sees through it all and is no longer living in fear.  He discovers his soul and the outside world is no longer separate, the lights no longer blinding, no difference between him and a replicant, or one of Sebastian's mechanical toys.

They are connected and have some similar ideas, and they might as well take place in the same world.