The following is from a knowledgable source: As far the numbering convention is concerned, the 11, 21, etc. is usually either based on the “go” of the day OR the the flight within a “go”. To explain, a “go” may usally consist of 12 jets. Of those 12, there may be three formations. Therefore, we normally assign the numbers of those formations as a sequence, . 11-14, 21-24, and 31-34. Where there are multiple flying squadrons at a base, they assign each squadron a series of 3 numbers, 0-8. Therefore, the same number suffix should not be flying with more than one formation at a time. This is also helps controls and pilots recognize their callsigns on the radio, especially if the radio transmission is clipped. For example, if all that is understood was “(radio static) 71, descend and maintain 3 thousand”, one would still know that the message was for callsign 71 and not callsign 51. The “91” callsign suffix is usually reserved for “checkride” sorties.
The collective results from the intravenous thrombolytic trials show a clear and consistent pattern. Patients treated with moderate-dose intravenous thrombolysis within 3 hours after the onset of stroke symptoms benefit substantially from therapy, despite a modest increase in the rate of symptomatic hemorrhage. Patients treated in the 3- to -hour window show a modest, but still clinically worthwhile, therapeutic yield. Beyond hours after onset, no net benefit of therapy has been demonstrated. Current US and international consensus guidelines accordingly recommend intravenous thrombolysis when treatment can be initiated within 3 hours from stroke onset, the most well-established treatment timeframe. [ 21 , 24 ]