Keel (bird anatomy) keel; and ratites (from "ratis", "raft" — referring to the flatness of the sternum), having a subtle keel structure or lacking one entirely. However, this classification has fallen into disuse as evolutionary studies have shown that many flightless birds have evolved from flighted birds. The current definition of Carinatae now includes all extant birds. Keel (bird anatomy) A keel or carina (plural carinae) in bird anatomy is an extension of the sternum (breastbone) which runs axially along the midline of the sternum and extends outward, perpendicular to the plane of the ribs. The keel provides an anchor to which a
Society for the Scientific Study of Sexuality Society for the Scientific Study of Sexuality The Society for the Scientific Study of Sexuality (SSSS, or "quad-S"), formed in 1957, is a non-profit, international professional membership organization, based in the United States, that says it is "the oldest professional society dedicated to the advancement of knowledge about sexuality." It reports to have more than 1,000 members and has a quarterly newsletter, "Sexual Science". It produces two other publications: According to its website, SSSS was established in 1957 by psychologist Albert Ellis to encourage the rigorous, systematic study of sexuality. In 1980, organizer Robert Francoeur invited Philadelphia biologist Timothy Perper