Here is the direct link for the breathing technique:
http://journals.plos.org/plosone/article/asset?unique&id=inf...
replies(3):
http://journals.plos.org/plosone/article/asset?unique&id=inf...
How does this part work? No real music does this so did they make their own for the study? Or do they select songs that change tempo subtley from one to the next?