do move eloquent namespaces 'using' c++?

when controlling c++ namespaces, move definitely name them, this:

std::cout << "hello, world!\n";

or move using namespace:

using namespace std;
cout << "hello, world!\n";

and if move latter, announce your usings during record duty scope?

personally i move definitely name - it's some-more typing nonetheless controlling reduction namespaces (e.g. std boost) i some-more readable.