expected because we are no longer dealing with a conformal field theory. Notice that the AdS$_{5}$ geometry is recovered in the limit of large energies ($|a|\to\infty$) and in the limit of massless matter $m_{i}\to 0$. Expanding the probe action in this background, we find that the pure scalar terms read

$${\eqalign{S={T_{3}\over 2}\int\Big(&\Big[\tau_{2cl}-
{3\tau_{2cl} \over 2\pi}m_{1}m_{2}m_{3}m_{4}\Big(
{q\over a^4}+{\bar{q}\over \bar{a}^4}\Big)\Big]
\partial_{m}a\partial^{m}\bar{a}\cr
+&\Big[{2N\pi\over (a\bar{a})^{2}}+
{\alpha Nm_{1}m_{2}m_{3}m_{4}(\tau_{2cl})^{2}\over4(a\bar{a})^{2}}
\Big({q\over a^{4}}+{\bar{q}\over\bar{a}^{4}}\Big)\Big]
\partial_{n}a\partial^{n}a
\partial_{m}\bar{a}\partial^{m}\bar{a}
\Big).}}$$

Notice that the correction to the four derivative terms has the structure of the one instanton corrections computed using field theory. We have not been able to fix $\alpha$ with our asymptotic analysis, so that the coefficient of this correction could not be checked. As reviewed above, instanton effects explicitly break the conformal symmetry of the field theory. The breaking of the $SO(2,4)$ conformal symmetry in the field theory is reflected in the corrections to the AdS$_{5}$ geometry, which break the $SO(2,4)$ isometry of the AdS$_{5}$ space. Note that the coupling runs with a power law. Solutions of type-0 string theories with a power law running for the coupling have been studied in . Power law running of the coupling has also played a prominent role in gauge-coupling unification in theories with 