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).
Examples of beta blockers used as heart attack medication include: 1  Atenolol (TenorminÂ®) 2  Metoprolol (LopressorÂ®) 3  Propranolol (InderalÂ®) 4  Metoprolol succinate (Toprol XLÂ®) 5  Carvedilol (CoregÂ®).