Iodine deficiency in China goitre. This disease causes a swelling in the neck, where the thyroid glands are, leading to impaired cognitive abilities. The child population was about 20% saturated with the disease but continues to decrease with the new initiatives. Another common IDD prevalent in China is Kashin-Beck disease. A particular outbreak in Tibet was recorded as occurring from lack of iodine. Kashin-Beck is a bone deformity endemic. Iodine deficiency, hypothyroidism, and low serum concentrations of thyroxine-binding globulin were significantly related to Kashin–Beck disease. Iodine supplemented irrigation water in combination to iodized salt helps in reducing the neonatal and infant mortality rates. The
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