Female black bears may give birth to 1 to 6 cubs (twins are most common) in January or February. Black bear cubs may be 1/250th the size of the mother bear, and are the smallest newborns, compared to their mothers, of any placental mammal.
A left ventricular assist device, or LVAD, is a mechanical pump that is implanted inside a person's chest to help a weakened heart pump blood. Unlike a total artificial heart, the LVAD doesn't replace the heart. It just helps it do its job. This can mean the difference between life and death for a person whose heart needs a rest after open-heart surgery or for people waiting for a heart transplant.
An arteriovenous fistula, or DAVF, is an abnormal connection of vessels in the tissues around the brain or spinal cord in which one or more arteries are directly connected to one or more veins or venous spaces called sinuses.