When summer heat comes to the Arara neighborhood in northern Rio, it lingers, baking the red brick and concrete that make up many of the buildings long after the sun has gone down. Luis Cassiano, who's lived here more than 30 years, says he's getting worried as heat waves become more frequent and fierce. In poor areas such as Arara, those who can afford air conditioning — Cassiano is one — can't always count on it because of frequent power outages on an overloaded system.

Tryptophan, found in food, is an important ingredient in the neurotransmitter serotonin. But is that enough to support it as a possible mood booster? The research is decidedly mixed.

Life span and outcome of dental inserts pivot fundamentally on post-technique care and continuous support. Furnished with savvy tips and practices,