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.
Too much calcium and iron can also lead to constipation. Calcium supplements, especially if taken with another supplement or medication that binds the stool, may also cause problems. Talk with your doctor if you have concerns.astor oil is a powerful laxative. But like other laxatives, it should not be used long-term. Overusing laxatives can hurt your body's ability to absorb nutrients and some medications. Castor oil can damage the bowel muscles, nerves, and tissue if overused -- all of which can cause constipation.