The San Diego Police Department said its officers would be on heightened alert against any potential threats to the Jewish community starting Wednesday, when Yom Kippur begins at sundown. "As always, when it comes to Yom Kippur, or any other significant event, we will conduct extra patrols in the areas where there are places of worship," SDPD spokesman Lt. Travis Easter said Tuesday. Yom Kippur services begin with the Kol Nidre, an ancient prayer that literally means "all vows" or "all promises." Yom Kippur concludes at sundown Thursday, ending the 10-day period on the Jewish calendar known as Days of Teshuvah, which is variously translated as repentance, return and change, and the Days of Awe. Many Jews fast on Yom Kippur and spend much of the time in synagogues.