Iodine deficiency Iodine deficiency Iodine deficiency is a lack of the trace element iodine, an essential nutrient in the diet. It may result in a goiter, sometimes as an endemic goiter as well as cretinism due to untreated congenital hypothyroidism, which results in developmental delays and other health problems. Iodine deficiency is an important public health issue as it is a preventable cause of intellectual disability. Iodine is an essential dietary mineral; the thyroid hormones thyroxine and triiodothyronine contain iodine. In areas where there is little iodine in the diet, typically remote inland areas where no marine foods are eaten, iodine deficiency
Trace field of a representation Trace field of a representation In mathematics, the trace field of a linear group is the field generated by the traces of its elements. It is mostly studied for Kleinian and Fuchsian groups, though related objects are used in the theory of lattices in Lie groups, often under the name "field of definition". Fuchsian groups are discrete subgroups of formula_1. The trace of an element in formula_1 is well-defined up to sign (by taking the trace of an arbitrary preimage in formula_3) and the "trace field" of formula_4 is the field generated over formula_5 by the traces of all elements