JQuery :: Adding Selectors To $(this)?

Writing a sortable list function. My <li> elements contain several items (headings, paragraphs etc) and I want to add a class to the headings when they've been sorted. I have this code in my sortable init:

receive: function(event, ui) {
$(ui.item).addClass('editable');
},

This adds class="editable" to my newly-sorted <li> element - cool. What I want, though, is to add this class to the <h3> within my <li>. I tried:

receive: function(event, ui) {
$(ui.item + ' h3').addClass('editable');
},

but this just gave a syntax error.