ANTIBIOTIC SUSCEPTIBILITY TESTING. Bacteria demonstrate two kinds of resistance to antibiotics, namely intrinsic resistance and acquired resistance. Intrinsic resistance means that the species was resistant to an antibiotic even before its introduction.
Radiation is naturally present in our environment, as it has been since before the birth of this planet. In addition, radiation can be produced artificially, as in medical x-rays and microwaves for cooking. Nonetheless, most people are not aware of all the natural and man-made sources of radiation in our environment.
Alpha, beta and gamma. There are three main types of radiation that can be emitted by radioactive particles. They are called alpha, beta, and gamma. All three types of radiation come from the nucleus of the atom. All three types of radiation will cause ionisation, but they behave slightly differently, because of the way they are made up. The diagram below shows the penetration of alpha, beta and gamma rays.