public function GetNotificationsSince($UserID, $LastActivityID, $FilterToActivityTypeIDs = '', $Limit = '5') {
      $this->ActivityQuery();
      $this->FireEvent('BeforeGetNotificationsSince');
		if (is_array($FilterToActivityTypeIDs))
			$this->SQL->WhereIn('a.ActivityTypeID', $FilterToActivityTypeIDs);
      else
         $this->SQL->Where('t.Notify', '1');
		
      $Result = $this->SQL
         ->Where('RegardingUserID', $UserID)
         ->Where('a.ActivityID >', $LastActivityID)
         ->Limit($Limit, 0)
         ->OrderBy('a.ActivityID', 'desc')
         ->Get();

      return $Result;
   }