I am looking into getting back to school to get a PhD in Mathematics or Computer Science (I hold MA in Math). I am wondering what new areas of research in Math and CS are promising in a sense that they have or will have extensive applications in real life? I understand that this question may sound too general, but I really need a perspective on this as I have been away from academia for quite some years. I worked in investments so one direction could be stochastic equations but this seems to be a beat-up path. I have heard of systems science, self-adaptive systems, which I feel like I could become interested. So I guess my question more specifically is this: what promising extensive real life applications are for Math and CS researchers beyond finance and military areas?