  The three-nucleon system is studied at energies a few hundred keV above the
N-d threshold. Measurements of the tensor analyzing powers $T_{20}$ and
$T_{21}$ for p-d elastic scattering at $E_{c.m.}=432$ keV are presented
together with the corresponding theoretical predictions. The calculations are
extended to very low energies since they are useful for extracting the p-d
scattering lengths from the experimental data. The interaction considered here
is the Argonne V18 potential plus the Urbana three-nucleon potential. The
calculation of the asymptotic D- to S-state ratio for $^3$H and $^3$He, for
which recent experimental results are available, is also presented.
