Ginger Gibson 3-4 minutes - Source: Reuters LOS ANGELES (Reuters) - Miles from where seven Democratic presidential hopefuls will take the debate stage on Thursday night in Los Angeles, Julian Castro on Wednesday walked the city’s Skid Row, the largest encampment of homeless people in the United States Democratic presidential candidate Julian Castro speaks with Chris Smith, a homeless man who lives in the nation's largest encampment of homeless people on Skid Row in Los Angeles, California, U.S. December 18, 2019. REUTERS/Ginger Gibson Castro, a former U.S. housing secretary, is among a handful of presidential candidates trying to find ways to stay in the conversation, after failing to meet the polling and donor requirements needed to qualify for Thursday night’s televised event. U.S. Senator Cory Booker, among the 15 Democrats vying to win the right to take on Republican President Donald Trump in November 2020, is launching a new television ad on