Loreta on a Mac ?

It is possible but: read what a commentator said about it. The virtual window systems that allow you to run Windows XP etc in a window on a Mac tend to use only one CPU or processor at a time. They also impose some significant additional penalties on access to memory, filesystems, etc. If you want to run Windows on systems ordinarily running OS/X, then you should consider setting up Apple's BootCamp (free software) that allows you to choose to run either OS/X or Windows (but not both at the same time) whenever you boot your machine - providing full access to CPUs / processors, memory, filesystems, etc - without any virtualization for the best possible performance. On the other hand, if you want to use Mac specific tools while running LORETA you might consider using Parallels or VMware - though your raw compute power will suffer - and you may need more memory if your application is memory intensive - as are most 3D volume imaging packages.