Men who have sex with men blood donor controversy not be accepted at any point in the future, thus constituting a de facto ban. Restrictions vary from country to country and in some countries practice of protected sex or periods of abstinence are not considered. The restrictions affect these men and, in some cases, any female sex partners. They do not otherwise affect other women, including women who have sex with women. The United States Food & Drug Administration (FDA) asserts that the one year deferral window is "supported by the best available scientific evidence". Many LGBT organizations view the restrictions on donation as based on homophobia and not
Moving average "S" to "Y" as shown above, though other techniques exist, such as setting "S" to an average of the first 4 or 5 observations. The importance of the "S" initialisations effect on the resultant moving average depends on "α"; smaller "α" values make the choice of "S" relatively more important than larger "α" values, since a higher "α" discounts older observations faster. Whatever is done for "S" it assumes something about values prior to the available data and is necessarily in error. In view of this, the early results should be regarded as unreliable until the iterations have had time