In the Hornbostel-Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a shell and struck, either directly with the player's hands, or with a drum stick, to produce sound.
Heat production can be calculated from a measurement of VO 2 and/or CO 2. Doubly-Labeled Water Doubly-labeled water contains isotopes of oxygen and of hydrogen. The technique involves the consumption by the patient of the doubly-labeled water then the measurement of the amount of isotope in the person after a washout period of 7- 14 days. Most of the hydrogen and oxygen isotopes are lost through excretion and evaporation, but some of the oxygen isotope equilibrates with carbon dioxide and is expired in air.
Coliform Testing. Testing for bacteria is the only reliable way to know if your water is safe. You cannot tell by the look, taste, or smell of the water if disease-causing organisms are in it. The New York State Department of Health recommends that well owners test their water for coliform bacteria at least once a year.