1 You have signs of infection, such as: 2  Increased pain, swelling, warmth, or redness around the bite. 3  Red streaks leading from the bite. 4  Pus draining from the bite.  A fever.
A negative index of refraction due to three-dimensional chirality is demonstrated for abilayered metamaterial based on pairs of mutually twisted planar metal patterns in parallel planes, which alsoshows negative electric and magnetic responses and exceptionally strong optical activity and circular dichro-ism.
For a spherically curved mirror in air, the magnitude of the focal length is equal to the radius of curvature of the mirror divided by two. The focal length is positive for a concave mirror, and negative for a convex mirror.In the sign convention used in optical design, a concave mirror has negative radius of curvature, so.he focal length of a lens determines the magnification at which it images distant objects. It is equal to the distance between the image plane and a pinhole that images distant objects the same size as the lens in question.