what is the first care unit of patient 31141 since 1 year ago?
select transfers.careunit from transfers where transfers.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 31141 ) and transfers.careunit is not null and datetime(transfers.intime) >= datetime(current_time,'-1 year') order by transfers.intime asc limit 1