Adrenal fatigue is a collection of signs and symptoms, known as a syndrome, that results when the adrenal glands function below the necessary level. Most commonly associated with intense or prolonged stress, it can also arise during or after acute or chronic infections, especially respiratory infections such as influenza, bronchitis or pneumonia.
Black holes are the strangest objects in the Universe. A black hole does not have a surface, like a planet or star. Instead, it is a region of space where matter has collapsed in on itself.
PK: Point Known, PK Nail PK Nail: A concrete nail made by Parker Kaelon (stamped PK) that marks a survey point; see also Hub and Tack in Surveyors' Slang. POB: Point of beginning, the starting point of a survey PRC: Point of reverse curve, the point in an S-type compound curve where two curves of different polarity meet