Vitiligo (pron.: /ˌvɪtɨˈlaɪɡoʊ/) is a condition that causes depigmentation of sections of skin. It occurs when melanocytes, the cells responsible for skin pigmentation, die or are unable to function. The cause of vitiligo is unknown, but research suggests that it may arise from autoimmune, genetic, oxidative stress, neural, or viral causes. The incidence worldwide is less than 1%. The most common form is non-segmental vitiligo, which tends to appear in symmetric patches, sometimes over large areas of the body.
Humans (Homo sapiens) are primates of the family Hominidae, and the only extant species of the genus Homo. Humans are characterized by having a large brain relative to body size, with a particularly well developed neocortex, prefrontal cortex and temporal lobes, making them capable of abstract reasoning, language, introspection, problem solving and culture through social learning. This mental capability, combined with an adaptation to bipedal locomotion that frees the hands for manipulating objects, has allowed humans to make far greater use of tools than any other species. Humans are the only extant species known to build fires and cook their food, as well as the only known species to clothe themselves and create and use numerous other technologies and arts. The scientific study of humans is the discipline of anthropology.
Humans are uniquely adept at utilizing systems of symbolic communication such as language and art for self-expression, the exchange of ideas, and organization. Humans create complex social structures composed of many cooperating and competing groups, from families and kinship networks to states. Social interactions between humans have established an extremely wide variety of values, social norms, and rituals, which together form the basis of human society. Humans are noted for their desire to understand and influence their environment, seeking to explain and manipulate phenomena through science, philosophy, mythology, and religion.
Documentary photography usually refers to a popular form of photography used to chronicle significant and historical events. It is typically covered in professional photojournalism, or real life reportage, but it may also be an amateur, artistic, or academic pursuit. The photographer attempts to produce truthful, objective, and usually candid photography of a particular subject, most often pictures of people.