It can cause nausea and diarrhea, especially in high doses or after long-term use. It might also pose a risk of ulcers in high doses. As a topical treatment, it can cause skin irritation. Caution is advised when turmeric is taken by people known to have gallstones; consult your health care provider first.
Gain is the ratio between the magnitude of output and input signals. Gain controls on an amplifier are basically just small potentiometers (variable resistors) or volume controls, that allow you to adjust the incoming signal to the amplifier.
A good antenna front-to-back ratio is normally 20 dB. An antenna can have a gain of 21 dBi, a front-to-back ratio of 20 dB or a front-to-side ratio of 15 dB. This means the gain in the backward direction is 1 dBi, and gain off the side is 6 dBi.