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.
Cyanosis is a bluish color in the skin, lips and nail beds caused by a shortage of oxygen in the blood. Cyanosis occurs because blood with decreased oxygen turns blue or purple. This low-oxygen blood causes a blue-purple tint to the skin. What conditions cause cyanosis? Cyanosis is usually caused by problems of the heart, lungs or blood. Some of the defects or diseases that can cause a child to have cyanosis are: truncus arteriosus. total anomalous pulmonary venous return. transposition of the great arteries. tricuspid atresia. pulmonary atresia. atrioventricular canal defect. pulmonary hypertension.