An association football (soccer) match is presided over by a referee, whom the Laws of the Game give full authority to enforce the Laws of the Game in connection with the match to which he has been appointed (Law 5). The referee is oftentimes assisted by two assistant referees, and sometimes by a fourth official.
Barfoed's test. Barfoed's test is a chemical test used for detecting the presence of monosaccharides. It is based on the reduction of copper(II) acetate to copper(I) oxide (Cu2O), which forms a brick-red precipitate.
In another (the Bravo test), the probe is attached to the lower portion of your esophagus during endoscopy. Ambulatory acid tests can help your doctor rule out acid reflux but not bile reflux. Esophageal impedance. This test measures whether gas or liquids reflux into the esophagus. It's helpful for people who regurgitate substances that aren't acidic (such as bile) and can't be detected by an acid probe. As in a standard probe test, esophageal impedance uses a probe that's placed into the esophagus with a catheter.