 This evening's news conference will be closely watched by Democrats who have raised concerns about Biden's ability to win and serve another four-year term. In Arizona, officials say at least three children have died following separate heat-related emergencies. From member station KJZZ, Catherine Davis-Young has more. A 10-year-old boy died last week in Phoenix after a hike on a 113-degree day. A four-month-old girl died Friday after being taken on a boat on Lake Hattie.