  We derive the spectral indices and their runnings of local form $f_{NL}$ and
$g_{NL}$ from a DBI isocurvature field and we find that the indices are
suppressed by the sound speed $c_s$. This effect can be interpreted by the
Lorentz boost from the viewpoint in the frame where brane is moving.

Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Phenomenology;High Energy Physics - Theory