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.
Type C has been found in humans, pigs, and dogs and causes either a very mild illness, or has no symptoms at all. It does not cause epidemics and does not have the severe public health impact that influenza types A and B do. The typical incubation period for influenza is 1 to 4 days, with an average of 2 days.Adults can be infectious from the day before symptoms begin through approximately 5 days after illness onset.Children can be infectious for. The incubation period of swine flu is one to 7 days. 2  People may be contagious from one day before they develop symptoms to up to 7 days after they get sick. 3  There are two influenza antiviral medications that are currently effective against H1N1 flu.