By Colleen Howe and Muyu Xu BEIJING/SINGAPORE (Reuters) -Oil prices reclaimed some ground on Thursday after tumbling to a six-month-low in the previous session, but investors remained concerned about sluggish demand and economic slowdowns in the U.S. and China. Brent crude futures rose 38 cents, or 0.5%, to $74.68 a barrel by 0409 GMT. U.S. West Texas Intermediate crude futures rose 42 cents, or 0.6%, to $69.80 a barrel. “Oil markets may have been oversold,” which could mean the recovery is a “short-term rebound,” said Tina Teng, a markets analyst with CMC Markets, in a note. In the previous s…