Table 2.

Mediator queries in FBIRN.

Information need	Mediator query	Variants	Correct answers (Size)	(Avg) response time (s)
Find all female subjects between the ages of 40 and 50.	Q(source, subjectid):- g_hasAge(source, subjectid, A) ^ g_hasGender(source, subjectid, G) and (40 < A < 50) ^ (G = “F”)	Vary age parameters, and constraints. on other aspects such as handedness, race etc	Yes (20–100 tuples)	2.3
Find all subjects with indications of Alzheimer's	Q(source, subjectid, CDR, MMSE):- g_Assessment(source, subjectid, “CDR,” C) ^ g_Assessment(source, subjectid, “MMSE,” M) ^ C > 3 and M > 10	Vary (subject) conditions being searched for.	Yes (2–35 tuples)	1.9
Find all fMRI scans taken with a 3T scanner	Q(source, subjectid, scan):- g_ExperimentAcquisition() ^ (ST = fMRI) ? (scanner = 3T)	Vary types of scans and/or scanners	Yes (30–35 tuples)	12.1