is peter petrelli still alive?

As with most superheroes, there always seems to be a weakness...as with Highlander, when the head is seperated from the body, it's over.

I strongly believe he is still alive. Nathan too. Yes, Peter has claire's powers. That makes him imortal. I.E He cannot die. He can only be made inmobile. I.e placing an object in his head or taking out his heart or something like that... Hmm.. thinking about it, since he has the power to regenerate, I wonder, if his heart is taken out, would he regenerate a new one or will he die??.. Whatever it is, as is Claire, Peter can not be disintegrated. Thus, cannot die.