A vassal or feudatory is a person who has entered into a mutual obligation to a lord or monarch in the context of the feudal system in medieval Europe. The obligations often included military support and mutual protection, in exchange for certain privileges, usually including the grant of land held as a fiefdom. The term can be applied to similar arrangements in other feudal societies. In contrast, a fidelity, or fidelitas, was a sworn loyalty, subject to the king.
In fully developed vassalage, the lord and the vassal would take part in a commendation ceremony composed of two parts, the homage and the fealty, including the use of Christian sacraments to show its sacred importance. According to Eginhard's brief description, the commendatio made to Pippin the Younger in 757 by Tassillo, Duke of Bavaria, involved the relics of Saints Denis, Rusticus, Éleuthère, Martin, and Germain – apparently assembled at Compiègne for the event. Such refinements were not included from the outset when it was time of crisis, war, hunger, etc.. Under feudalism, those who were weakest needed the protection of the knights who owned the weapons and knew how to fight.
Feudal society was increasingly based on the concept of "lordship" (French seigneur), which was one of the distinguishing features of the Early Middle Ages and had evolved from times of Late Antiquity.
.hiv is a generic top-level domain (gTLD) proposed by the Berlin-based nonprofit dotHIV and owned by Uniregistry as of September 2014. It is the first open charitable gTLD and its ICANN designation states that the domain's operator is precluded from making a profit. Funds raised from .hiv domain sales will initially benefit projects to increase access to HIV/AIDS treatment in Rwanda, South Africa, Turkey, and the United States.
The top-level domain (TLD) was inspired by the anti-HIV/AIDS campaign by thjnk, a German advertising agency. thjnk's co-owner Michael Trautmann established dotHIV gemeinnütziger e.V. as a nonprofit and applied for the .hiv TLD. Despite the global relevance of HIV/AIDS, dotHIV was the only applicant for the .hiv TLD. The company signed a registration contract with ICANN in March 2014. Domains were made available for select companies and individuals during the July "sunrise" period, becoming generally available in August 2014. hiv became the first open charitable TLD and, according to one press release, "opens up a dedicated namespace that brings website owners together behind one goal: The end of AIDS".
HIV infects vital cells in the human immune system such as helper T cells (specifically CD4+ T cells), macrophages, and dendritic cells. HIV infection leads to low levels of CD4+ T cells through a number of mechanisms, including pyroptosis of abortively infected T cells,apoptosis of uninfected bystander cells, direct viral killing of infected cells, and killing of infected CD4+ T cells by CD8 cytotoxic lymphocytes that recognize infected cells. When CD4+ T cell numbers decline below a critical level, cell-mediated immunity is lost, and the body becomes progressively more susceptible to opportunistic infections.