They are present in approximately 60 to 80 percent of people diagnosed with RA. Studies have found that, for many people, the antibodies precede the development of clinical symptoms by 5 to 10 years. If you have symptoms consistent with RA and a positive test for the antibody, an RA diagnosis is almost a certainty.Previously, seropositivity was defined in terms of an antibody called rheumatoid factor (RF).f you have symptoms consistent with RA and a positive test for the antibody, an RA diagnosis is almost a certainty. Previously, seropositivity was defined in terms of an antibody called rheumatoid factor (RF).
Clark Leonard Hull (May 24, 1884 â May 10, 1952) was an influential American psychologist who sought to explain learning and motivation by scientific laws of behavior.Hull is known for his debates with Edward C. Tolman.He is also known for his work in drive theory.Hull spent the mature part of his career at Yale University, where he was recruited by the president and former-psychologist, James Rowland Angell.lark Hull found inspiration for his own theory of learning after learning about Ivan Pavlov âs idea of conditional reflexes, and Watson âs system of behaviorism.
According to the theory, the reduction of drives is the primary force behind motivation. Hull was one of the first theorists to attempt creating a grand theory designed to explain all behavior. While the drive-reduction theory of motivation was once a dominant force in psychology, it is largely ignored today.