General Pharmacology. Beta-blockers are drugs that bind to beta-adrenoceptors and thereby block the binding of norepinephrine and epinephrine to these receptors. This inhibits normal sympathetic effects that act through these receptors. Therefore, beta-blockers are sympatholytic drugs.
Don't know much about the origins of daylight saving time? Maybe it's time to learn about the semi-annual time shift, which goes into effect on Sunday across most of the U.S. and in 69 other countries around the world. Benjamin Franklin is sometimes credited with the invention of daylight saving time.
When it began. Daylight saving time has a rocky past. Established in the United States in 1918, daylight saving time was a contentious matter and was repealed in 1919. The standardized clock changes, however, were re-established nationally early in World War II and observed from Feb. 9, 1942 through Sept. 30, 1945.