of 174 respondents and acceptance of males in the nursing profession by multiple regression analysis has indicated that only two of the variables, namely, respondents' educational level and sex, significantly predict the attitudes toward male nurses (Laroche and Livneh, 1983).
I have always used by end of business which normally means by 5pm. I think that it depends on who you are sending the email to. If it is a superior you might want to reconsider and define an exact time deadline. If it is to a subordinate giving a general time frame like end of today or end of the day would be fine. share|improve this answer.
For perspective's sake, closing delays have become so common with so many little things that can go wrong that agents often view closing dates only as a light at the end of a tunnel rather than a firm sign-off date. Even so, it would be wise to resolve and meet all contingencies with due speed, given the market.