  Gau{\ss}-Manin determinant connections associated to irregular connections on
a curve are studied. The determinant of the Fourier transform of an irregular
connection is calculated. The determinant of cohomology of the standard rank 2
Kloosterman sheaf is computed modulo 2 torsion. Periods associated to irregular
connections are studied in the very basic $\exp(f)$ case, and analogies with
the Gau{\ss}-Manin determinant are discussed.
