Network protocols that use aggressive retransmissions to compensate for packet loss due to congestion can increase congestion, even after the initial load has been reduced to a level that would not normally have induced network congestion. Such networks exhibit two stable states under the same level of load.
Beta blocker. Beta blocker, also written Î²-blocker, is a class of medications that are particularly used to manage cardiac arrhythmias, and to protect the heart from a second heart attack (myocardial infarction) after a first heart attack (secondary prevention).
Medications can slow down a heartbeat that is too fast. They can also be used to even out or stabilize an abnormal heart rhythm. Classes of drugs used to treat arrhythmias include beta blockers, anticoagulants, calcium channel blockers, and anti-arrhythmic drugs.