/** Possible actions for calling a participant: call, comments */
 function participant_call_actions($participant_id, $experiment_id, $weeks_ahead = WEEKS_AHEAD)
 {
     $CI =& get_instance();
     $pp = $CI->participantModel->get_participant_by_id($participant_id);
     $call_link = img_call_p($pp, $experiment_id, $weeks_ahead);
     $nr_comments = count($CI->commentModel->get_comments_by_participant($participant_id));
     $com_link = $nr_comments > 0 ? anchor('comment/participant/' . $participant_id, img_comments($nr_comments)) : img_comments();
     return implode(' ', array($call_link, $com_link));
 }
 /** Possible actions for a participation: prioritize and delete */
 function participation_callback_actions($participation_id)
 {
     $CI =& get_instance();
     $participation = $CI->participationModel->get_participation_by_id($participation_id);
     $participant = $CI->participationModel->get_participant_by_participation($participation_id);
     $call_link = img_call_p($participant, $participation->experiment_id);
     $actions = array($call_link);
     return implode(' ', $actions);
 }