The uncertainty principle asserts a limit to the precision with which position x and momentum p of a particle can be known simultaneously. You may know the probability distributions of x and p individually but the joint distribution makes no physical sense. Yet Wigner exhibited such a joint distribution f(x, p). There was, however, a little trouble with it: some of its values were negative. Nev...

the nosocomial infections, caused by multi-drug resistant bacteria, are the most important cause of mortality throughout the world. one important mechanism against beta-lactam antibiotics is the production of beta-lactamases. enterobacteriaceae and non-fermentative bacteria, like pseudomonas aeruginosa and acinetobacter baumannnii may produce these enzymes. currently, there is no vaccine to pre...