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).
Many different medications are used in the treatment of heart failure. They include: 1  Angiotensin-converting enzyme (ACE) inhibitors. 2  Angiotensin-receptor blockers (ARBs). 3  Beta blockers. 4  Diuretics. 5  Aldosterone blockers. 6  Digitalis. 7  Hydralazine and nitrates.ldosterone is a hormone that is critical in controlling the body's balance of salt and water. Excessive levels may play important roles in hypertension and heart failure. Drugs that block aldosterone are prescribed for some patients with symptomatic heart failure.