APPLICATIONS Horn antennas are widely used as satellite dishes and radio telescopes. Antennas 6 2. PARABOLIC ANTENNAS A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves.
Flu (influenza). Flu is usually infectious a day before symptoms start and remains infectious for about five to six days. Children and people with lowered immune systems may be infectious for a few days longer.
Influenza, commonly called the flu, is caused by viruses that infect the respiratory tract. Flu symptoms include fever, chills, cough, sore throat, headache, muscle aches, and. fatigue. The incubation period for flu is about one to four days. Flu is contagious, and symptoms may last up to seven to 14 days.