A-V Valves Open; Semilunar Valves Closed. This is the first phase of the cardiac cycle. It is initiated by the P wave of the electrocardiogram (ECG), which represents electrical depolarization of the atria. Atrial depolarization initiates contraction of the atrial musculature.
Community Q&A. You can calculate age on Excel for a many applications by combining an undocumented function and the date format for cells. Microsoft Excel internally stores dates as serial numbers, which is the number of days a date is from Jan. 1, 1900.
Excel NOW Function. One of Excel's best known date functions is the NOW function and it can be used to quickly add the current date and/or time to a worksheet, as shown in the examples in rows two and three in the image above. returning the current minute - row eight above. NOW Function Syntax and Arguments.