The automatic cab signal system shall be arranged so that cab signals will be continuously controlled in accordance with conditions described in Â§ 236.205 that obtain at least stopping distance in advance. Â§ 236.512 Cab signal indication when locomotive enters block where restrictive conditions obtain.
Dissolved oxygen (DO) is a measure of the quantity of free oxygen molecules in water. The concentration of DO is an important indicator of the health of an aquatic ecosystem because oxygen is essential for almost all forms of life. Oxygen is necessary for respiration and for some chemical reactions.
Low Blood Oxygen. The oxygen levels in blood can be measured by two means - first checking the arterial blood gas by resorting to a blood test, and second, by using a pulse oximeter (a device which is clipped on to the finger and to take oxygen readings in the blood).