Endemic goitre by significant compression of nearby structures. Endemic goitre Endemic goiter is a type of goitre that is associated with dietary iodine deficiency. Some inland areas where soil and water lacks in iodine compounds and consumption of marine foods is low are known for higher incidence of goitre. In such areas goitre is said to be "endemic". This type of goiter is easily preventable. In most developed countries regulations have been put into force by health policy institutions requiring salt, flour or water to be fortified with iodine. Treatment of endemic goiter is medical with iodine and thyroxine preparations. Surgery is
Trace field of a representation algebra formula_12 is then as simple as possible, more precisely: The algebra formula_12 is called the quaternion algebra of formula_4. The quaternion algebra of formula_7 is called the "invariant quaternion algebra" of formula_4, denoted by formula_24. As for trace fields, the former is not the same for all groups in the same commensurability class but the latter is. If formula_4 is an arithmetic Fuchsian group then formula_26 and formula_24 together are a number field and quaternion algebra from which a group commensurable to formula_4 may be derived. The theory for Kleinian groups (discrete subgroups of formula_29) is mostly similar as