The latest edition should always be the term in that taxonomy with the highest term_id, right? Query get_terms and find the latest edition, then use that term to build the rest of your query…
$edition = get_terms('edition','orderby=none&order=DESC&number=1');
$latest_edition = $edition[0]->slug;
Then you can either modify the current query, if that’s what you want to do:
global $wp_query;
$wp_query->set('edition',$latest_edition);
Or use it to build new queries:
$studiesposts = get_posts('category_name=Studies&edition='.$latest_edition);
If you have your permalink structure set up, it should also work to build urls for new links, like this:
http://yourdomain.com/edition/34/category/studies