What is e and ui in function(e,ui)

What is e and ui in function(e,ui)


Hi!
I'm currently playing with sortable lists. I have two lists that are
connected with each other.
When an item is dragged from one list to the other a want to
manipulate that item but i don't know how.
I've fugired out that i should use the receive option. Then there are
two arguments... e and ui. I don't quite understand what they are and
how i can use them. I need some explenation.
$("#left").sortable({
connectWith:["#right"],
receive:function(e,ui){
}
});
Thanks!