Q:

How to show "New" if the node author is registered within 4 weeks. 

I would like to print "New" if the node author is registered within 4 weeks in a field of "node View" by using custom php with Views Custom Field. I tried the code below but didn't work. Am I missing something?     
   <?php
      $four_weeks_ago = time() - (28 * 24 * 60 * 60);

      $user_created_time=$user->created;

    if ( $user_created_time >= $four_weeks_ago) {
        $this_user_is_new="new";
        print $this_user_is_new;
      }
    ?>

A:

What if you edit Vikas code with:
$node_author = user_load($node->uid);
$author_created_time = $node_author->created;

