Depression is a mental disorder, but at some times is not treated as one. Depression is never to be taken lightly, and should always be taken very seriously.    Some symptoms of depression are:   - Lack of interest in normally enjoyable activities.
IU (international unit): An international unit (IU) is an internationally accepted amount of a substance. This type of measure is used for the fat-soluble vitamins (such as vitamins A, D and E) and certain hormones, enzymes, and biologicals (such as vaccines).The definition of an international unit (IU) is generally arbitrary, technical, and eminently forgettable.For example, an IU of vitamin E is the specific biological activity of 0.671 milligrams of d-alpha-tocopherol. Nonetheless, most IUs are quite handy and helpful in use as a means of standardizing measures.he definition of an international unit (IU) is generally arbitrary, technical, and eminently forgettable. For example, an IU of vitamin E is the specific biological activity of 0.671 milligrams of d-alpha-tocopherol.
The International System of Units (SI) All systems of weights and measures, metric and non-metric, are linked through a network of international agreements supporting the International System of Units. The International System is called the SI, using the first two initials of its French name SystÃ¨me International d'UnitÃ©s. The key agreement is the Treaty of the Meter (Convention du MÃ¨tre), signed in Paris on May 20, 1875. 48 nations have now signed this treaty, including all the major industrialized countries.