You can now replace Google Now’s quick startup function with Cortana

[cdmagurus.com]

The latest beta update for Cortana has introduced a feature which allows you to have it take over the standard quick launch button for Google Now, which is typically facilitated by a long-press of the home button on most Android phones.

More... (http://phandroid.com/2015/08/10/cortana-quick-launch-command/)