Pseudo-code written down somewhere is protected by copyright, even if the article containing it doesn't say anything about the pseudo-code contained in it (i.e. doesn't mention "this too is copyrighted"). For example, let us assume that the following isn't actual compileable / executable code in some extant programming language:
procedure bubbleSort( A : list of sortable items )
n = length(A)
swapped = false
for i = 1 to n-1 inclusive do
/* if this pair is out of order */
if A[i-1] > A[i] then
/* swap them and remember something changed */
swap( A[i-1], A[i] )
swapped = true
until not swapped
It does nevertheless constitute an expression of an abstract algorithm. If it can be copied and pasted, it is an expression. If you run this through a filter to create executable code in some language, you will have created a derivative work (and possibly one with no copyright protection, if the conversion is totally automatic). If you read the lines and say "Ah, I know what that would be in Pascal", that has the modicum of creativity required to make your conversion protected, but you've still infringed the underlying work.
On the other hand, a logical flow chart, which is a picture of the abstract idea of what to do, is copyright-protected only as a graphic object. If you look at it and it inspires you to write pseudo-code or actual code, you are not copying the flow chart.