Sulfur exists in two allotropic forms. Allotropes are forms of an element with different physical and chemical properties. The two forms of sulfur are known as Î±-form and Î²-form (the Greek letters alpha and beta, respectively).
National Organizations American Psychological Association (APA) The American Psychological Association (APA) is located in Washington, D.C., and is the largest scientific and professional organization representing psychology in the United States. APA was founded at the turn of the 20th century, and is the world's largest association of psychologists. APA - Division 16 - Division of School Psychology
International Psychogeriatrics is the official journal of the International Psychogeriatric Association. Many fellowships in geriatric psychiatry exist. The American Journal of Geriatric Psychiatry is the official journal of the American Association for Geriatric Psychiatry. The American Board of Psychiatry and Neurology and the American Osteopathic Board of Neurology and Psychiatry both issue a board certification in geriatric psychiatry.