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).
A beta blocker is often used to treat high blood pressure or an irregular heart beat. This medicine can also be used to treat congestive heart failure, but people with severe heart failure may not be able to take a beta blocker. A beta blocker reduces the risk of another heart attack for people who have already had one.