尚活 can still work without 着? Can this two hanzi alone "尚活" support the meaning "still alive" without this last one "着"? 

And if yes, what does "着" add to the general sense? 
I mean, what's the difference between "活着" and "活"? I've seen both used in similar situations, and I found this "尚活着" written poem without a real grammatic context, so I wandered if "活" alone can't stand the meaning "alive" in an abstract text.
see grammar,dictionaries,bkrs：活：to live
alive living （work workmanship）动
（生存; 有生命） live:
吃为了活，不要活为了吃。 Eat to live， but do not live to eat.
他们将永远活在我们心中。形
（在活的状态下） alive; living:
活老虎 a live tiger
活捉 capture alive
活字典 a walking dictionary

着 durative aspectual particle,动态（时态）助词，表示动作还在持续,

活着 I
[live] 度过生活
我只为科学而活着, 也只关心科学
II
(1) [alive; living]∶有生命; 非死状态
他站在死去的和活着的人们之间
(2) [surviving]∶仍然有生命, 仍然没死
我青年时期一个仍然活着的朋友
it might seem therefore that 尚活 could mean "still alive, living" cf. 尚病,年岁尚小,尚未死，but in fact 尚活 always seems to be followed by 着, web shows exceptions LOFALi爱尚活的微博_微博,尚活族