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Each year in the United States, there are approximately six million pregnancies. This means that at any one time, about 4% of women in the United States are pregnant.
Vampire bats have a natural anticoagulant in their saliva that permits continuous bleeding after they painlessly open a wound with their incisors. This capillary blood does not cause any significant blood loss to their victims.
Since 1988, the CDC has reported a 99% reduction in bacterial meningitis caused by Haemophilus influenzae, due to the introduction of the vaccine against it.
Anesthesia awareness is a potentially disturbing adverse effect wherein patients who have been paralyzed with muscle relaxants may awaken. They may be aware of their surroundings but unable to communicate or move. Neurologic monitoring equipment that helps to more closely check the patient's anesthesia stages is now available to avoid the occurrence of anesthesia awareness.
The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."