You can do this through an indirect method:
[ul][li]Use the RelateObjects module to relate the nuclei as children and the foci as parents. This is the opposite of what is normally done but the key is to associate the nuclei measurements with the foci, not the other way around.[/li]
[li]Also in RelateObjects, check the “Calculate per-parent means…” box. If you have measured the nuclei intensity beforehand, the mean nuclei intensity is the same as the nuclei intensity itself, since there’s just one nuclei per foci.[/li]
[li]Use the CalculateMath module to subtract two foci object measurements in this order: [list]The foci MeanIntensity[/li][li]The mean nuclei MeanIntensity with 1.3 as the multiplication factor[/li][/ul]The result of this is a new foci measurement that will be positive where the foci mean intensity > 1.3nuclei mean intensity and negative otherwise.[/*:m]
[li]Use FilterObjects to filter the foci using Limits as the filtering method, the new Math measurement as the measure to filter by, leaving the minimum measurement value box checked and maximum measurement value unchecked, and the minimum value as 0.[/li][/list:u]
I believe this procedure should give you the results you want.