Viruses cause most cases of pneumonia in preschool-aged children (i.e., four months to five years of age).1, 9, 16, 24 Although most physicians start antibiotic therapy, guidelines allow for withholding treatment if a viral etiology is suspected and close follow-up can be ensured.1, 9, 13, 15, 16, 24 These children usually have associated symptoms of viral infection, such as pharyngitis, rhinorrhea, and diarrhea .1
Backgrounder on Plutonium. Printable Version. Plutonium is a radioactive metallic element with the atomic number 94. It was discovered in 1940 by scientists studying how to split atoms to make atomic bombs. Plutonium is created in a reactor when uranium atoms absorb neutrons.Nearly all plutonium is man-made.rintable Version. Plutonium is a radioactive metallic element with the atomic number 94. It was discovered in 1940 by scientists studying how to split atoms to make atomic bombs. Plutonium is created in a reactor when uranium atoms absorb neutrons. Nearly all plutonium is man-made.
radioactive element, an element subject to spontaneous degeneration of its nucleus accompanied by the emission of alpha particles, beta particles, or gamma rays. All elements with atomic numbers greater than 83 are radioactive.Naturally occurring radioactive elements include radium, thorium, and uranium.Several radioactive elements not found in nature have been produced by the bombardment of stable elements with subatomic particles in a cyclotron. Compare stable element.See also radioactivity.aturally occurring radioactive elements include radium, thorium, and uranium. Several radioactive elements not found in nature have been produced by the bombardment of stable elements with subatomic particles in a cyclotron. Compare stable element. See also radioactivity.