Since the 1980s, contemporary parapsychological research has waned considerably in the United States. Early research was considered inconclusive, and parapsychologists were faced with strong opposition from their academic colleagues. Some effects thought to be paranormal, for example the effects of Kirlian photography (thought by some to represent a human aura), disappeared under more stringent controls, leaving those avenues of research at dead-ends. The bulk of parapsychology research in the US is now confined to private institutions funded by private sources. After 28 years of research, Princeton Engineering Anomalies Research Laboratory (PEAR), which studied psychokinesis, closed in 2007.