Skin discoloration can be due to changes in melanin. Melanin is a skin pigment that gives color to the skin. Changes in melanin can also cause skin to be patchy. Treatment for skin discoloration includes using topical treatments.
Winglets increase an aircraft's operating efficiency by reducing what is called induced drag at the tips of the wings. An aircraft's wing is shaped to generate negative pressure on the upper surface and positive pressure on the lower surface as the aircraft moves forward.
Some points to note are: 1  Winglets and other wingtip devices reduce the intensity of the vortices, not eliminate them. ' 2 Closing' the wing or wing tip does not eliminate the trailing vortex wake or induced drag.