Vaccines and alergies

I'm not with those people that blames vaccines for baby autism and all the other health issues in a child. I think that there are many other things that might affect a child, including genetics and psychological issues.

Actually I found vaccines to be useful overall: I still see the effects of polio on people that were not vaccinated. I just wander if we really understand all the possible side effects of the way we are doing vaccination at this moment.

Wild question: is it possible that the vaccines increases the chance of developing various allergies? I'm not talking about the rare allergies immediately after the vaccine shot. I wander if, playing with the immune system, vaccines might also predispose to long time allergic reactions to various substances, like mites, pollen, peanut butter, eggs, etc.


Can a computer (or human) simulate itself?

A virtual machine is a common example of simulation. It can take the description of a (virtual) "computer" state and continue the execution from that point on. You can simulate a huge computer given a computer with more memory than the virtual machine, although it might be way slower. However, such virtual machine does not answer the problem because it normally simulates a computer with less memory.

The question is, can a computer to simulate a virtual computer that has the same capabilities as itself? Before answering this, let's exclude some trivial (forbidden) cases of "simulations":
  1. A calculator will always do exactly what it does, it will be identical with itself, we will not call this a simulation of itself.
  2. Copying the exact state of another identical computer in a "twin brother" will not be considered simulation.
  3. Starting 2 identical computers with the same input will not be considered like one is simulating the other.