Transfer Standards To briefly review, a frequency calibration compares the device under test (DUT)to a reference. The DUT is usually a quartz, rubidium, or cesium oscillator. Thereference is an oscillator of higher performance than the DUT or a transfer standardthat receives a radio signal.13).Calibration MethodsTo review, frequency standards are normally calibrated by comparing them to atraceable reference frequency. In this section, weâll discuss how this comparison ismade. To begin with, letâs look at the electrical signal produced by a frequencystandard.
Further information: Factitious diarrhea. The most common cause of melanosis coli is the extended use of laxatives, and commonly anthraquinone containing laxatives such as Senna, Aloe Vera and other plant glycosides. The anthranoid laxatives pass through the gastrointestinal tract unabsorbed until they reach the large intestine, where they are changed into their active forms.
Laxative (purgatives, aperients) are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation. Laxatives vary based on how they work and the side effects they have. Certain stimulant, lubricant and saline laxatives are used to evacuate the colon for rectal and bowel examinations, and may be supplemented by enemas under certain circumstances. Sufficiently high doses of laxatives may cause diarrhea.