Studies on immune responses in afferent and efferent lymph of lymph nodes draining the tissues have contributed to the concept that primary immune responses are generated in the lymph nodes with a delay before antigen-specific effector cells arrive at the affected tissue.
Lightning strikes the ground approximately 25 million times each year in the U.S. According to the NWS, the chance of an individual in the U.S. being killed or injured during a given year is one in 240,000. Assuming an average life-span of 80 years, a person's odds over their lifetime becomes one in 3000.
There is estimated to be around 2,000 lightning storm active around the global at one time creating over 100 strikes per second. These thunderstorms generate a potential difference of 200,000 to 500,000 volts between the Earthâs surface and the ionosphere, with a fair weather current of about 2Ã10-12 amperes/meter2. Data from NASAâs space-based optical sensors revealing the uneven distribution of worldwide lightning strikes.