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Radiation hormesis is the conjecture that a low level of ionizing radiation (i.e., near the level of Earth's natural background radiation) helps "immunize" cells against DNA damage from other causes (such as free radicals or larger doses of ionizing radiation), and decreases the risk of cancer. The theory proposes that such low levels activate ...
An example of a fully natural ecosystem might be a meadow or old-growth forest affected by fallout from a nuclear accident such as Chernobyl or Fukushima, while a semi-natural ecosystem might be a secondary forest, farm, reservoir, or fishery that is at risk of infection from some source of radionuclides.
For example, alpha radiation has low penetration and is not a hazard outside the body, but emitters are carcinogenic when inhaled or ingested. For example, Thorotrast , a (incidentally radioactive) suspension previously used as a contrast medium in x-ray diagnostics, is a potent human carcinogen known because of its retention within various ...
The radiation captured by the sensor is corrected for atmospheric disturbance and radiation noise to compute the brightness temperature of the ocean surface. With a correct estimation of the emissivity of sea water (~0.99) the grey body temperature of the ocean surface can be deduced, also referred to as the Sea Surface Temperature (SST).
Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic , and epigenetic levels and abnormal cell division .
High radiation dose gives rise to deterministic effects which reliably occur above a threshold, and their severity increases with dose. Deterministic effects are not necessarily more or less serious than stochastic effects; either can ultimately lead to a temporary nuisance or a fatality. Examples of deterministic effects are:
Evidence for hormetic effects was reviewed, with emphasis on material published since the 1990 BEIR V study on the health effects of exposure to low levels of ionizing radiation. Although examples of apparent stimulatory or protective effects can be found in cellular and animal biology, the preponderance of available experimental information ...
Biological oceanography is the study of how organisms affect and are affected by the physics, chemistry, and geology of the oceanographic system.Biological oceanography may also be referred to as ocean ecology, in which the root word of ecology is Oikos (oικoσ), meaning ‘house’ or ‘habitat’ in Greek.