Scholars debate the exact dates of the Sothic periods in relation to ancient Egyptian calendrical reforms.

Researchers tracked hormone levels across multiple ovulatory periods to better understand fertility patterns.

Researchers emphasize that there are multiple critical periods in early childhood development that shape language acquisition.

Most companies set probationary periods to evaluate new employees' performance.

The historian compared artifacts from different periods of time to understand cultural changes.

Historians often compare different time periods to understand social change.

Many museums have closed periods during renovations, so check the schedule before visiting.

On Fridays, a few students choose to enroll in zero periods to get ahead on credits.

Employees should be aware that different departments may have different notice periods.

Many people experience mood swings and cramps before and during their menstrual periods.