At least 15 people have died as a result of a massive electricity outage that has crippled Venezuela, as doctors struggled to assist patients, telecommunications networks were wiped out and the sale of basic goods was paralyzed amid rising political turmoil. Power returned sporadically to parts of the country after electricity first went out on Thursday afternoon. But another massive outage on Saturday plunged the capital, Caracas, back into darkness and sparked at least one looting attempt at a food market. …