The world's second nuclear explosion was achieved with uranium-235. This isotope is unstable and fissions when struck by a neutron. It is, however, found in natural uranium at a concentration of only 0.7 percent. To be useful in nuclear weapons, the concentration must be increased.
Introduction. Influenza, or flu, is a caused by a virus infecting the respiratory system, meaning your nose, throat, bronchial tubes, and lungs. Flu symptoms are usually more severe than those of the common cold and are more likely to affect other parts of your body.
Test for Influenza. Influenza is a viral respiratory infection. It tends to be seasonal, and causes headaches, chills, blocked nose, muscle pains, cough, and sore throat. Influenza symptoms are more intense and tend to last longer than the regular flu or cold.