change regular/staccato/staccatissimo midi duration 2.19.80

[Gianmaria Lari]

This code generate some 'regular', staccato and staccatissimo notes:

\version "2.19.80"

\score {

  \fixed c' {c8 d e-. f-. g-! a-! r4}

  \midi{}

  \layout {}

}

Is there any way to change the default duration of 'regular', staccato and staccatissimo notes?

Thank you, g.

P.S. For instance, with the articulate script I could change the staccato in this way: 

#(define ac:staccatoFactor '(1 . 6))