Hives on dark skin. Hives are a skin reaction that causes red or white itchy welts. The welts vary in size and appear and fade repeatedly as the reaction runs its course. Chronic hives are a condition in which the welts last more than six weeks or recur over months or years.Chronic hives usually aren't life-threatening. But the condition can be very uncomfortable and interfere with sleep and daily activities. Often, the cause of chronic hives is not clear.In some cases, chronic hives are a sign of an underlying health problem, such as thyroid disease or lupus. You can try various treatments to relieve your symptoms. For many people, antihistamine and anti-itch medications provide relief from chronic hives.hronic hives are a condition in which the welts last more than six weeks or recur over months or years. Chronic hives usually aren't life-threatening. But the condition can be very uncomfortable and interfere with sleep and daily activities. Often, the cause of chronic hives is not clear.
longitudinal magnetization. 1  of a material or medium in a manner in which the magnetic flux is essentially parallel to the long axis of the influencing field. 2  In magnetic recording, 3  of a material or medium essentially in the same direction as the material or medium is traveling.
Magnetism is a class of physical phenomena that are mediated by magnetic fields. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments.ecause this is a cross product, the force is perpendicular to both the motion of the particle and the magnetic field. It follows that the magnetic force does no work on the particle; it may change the direction of the particle's movement, but it cannot cause it to speed up or slow down.