Iodine deficiency French, the term "crétin des Alpes" also became current, since the condition was observed in remote valleys of the Alps in particular. The word "cretin" appeared in English in 1779. While reporting recent progress towards overcoming iodine-deficiency disorders worldwide, "The Lancet" noted: "According to World Health Organization, in 2007, nearly 2 billion individuals had insufficient iodine intake, a third being of school age." A conclusion was made that the single most preventable cause of intellectual disability is that of iodine deficiency. There is preliminary evidence that iodine deficiency enhances the sensitivity of breast tissue to estrogen. In rats treated with
Trace field of a representation of formula_4 (see for example in ). The "invariant trace field" is equal to the trace field of the subgroup formula_7 generated by all squares of elements of formula_4 (a finite-index subgroup of formula_4). The invariant trace field of Fuchsian groups is stable under taking commensurable groups. This is not the case for the trace field; in particular the trace field is in general different from the invariant trace field. Let formula_4 be a Fuchsian group and formula_11 its trace field. Let formula_12 be the formula_11-subalgebra of the matrix algebra formula_14 generated by the preimages of elements of formula_4. The