In medical studies, treatments are tested within a group of study participants. You will be given a sentence of a study report in which your task is to list the phrases that give information about the participants of the study. You should list the phrases in the same order that they appear in the text, separated by commas. If no information about the participants is mentioned, just output "not found". Relevant information about participants include: gender, medical conditions, location, number of people participating. Do not contain participant mentions without relevant information.

Q: Previous analyses that focused on health care underestimated this economic burden , particularly for school systems .

A: not found
****
Q: Participants were 236 heavy drinking smokers in a randomized clinical trial testing the efficacy of incorporating brief alcohol intervention into smoking cessation treatment .

A: 236 heavy drinking smokers
****
Q: The origin of the gastric phasic activity patterns is unknown , but they may be related to electrical control activity .

A:
not found
****