Social and political criticisms
From CNN News | April 22, 2013
Outfront investigators and David Mattingly saw how a pressure cooker bomb works. The shock wave, blast, and sharpnel goes ahead of the sound of the blast, thus you could be dead before you hear it.
The investigators were in a bunker some 1/4 mile away from the bomb and used nuts instead of nails. The effect was devastating. While the blast, very similar to the picture on Boston (with white plume) as only 20 ft across, the shock wave and sharpnel moved farther.
Thus for the first responder they should be wary of the danger posed by the sharpnel right after explosion
The bomb costs less than $100 to make yet is very deadly; it should not inspire local youth to copy this deadly adventure.
If you have weak personality, and you to US, then you become a deadly menace to US society.
I hope Americans do not become xenophobic to migrants (arent they yet?)