What type of feed does Nature Magazine use?

I tried to parse nature magazine's feed using php and several different rss/atom reader yet I can't find a proper way of reading them.

Their feed structure is bizzare to me its not RSS for sure but by the help of atom readers I couldn't get any proper answer too.

example : http://feeds.nature.com/nphys/rss/current

Anyone knows what is their feed type and how to parse them?