Geil Vidal's life was all books and calculations at home in Lima, Peru, where she was studying mechanical engineering and writing a thesis. Here, atop a Connecticut Avenue apartment building, the 23-year-old sits poolside beneath a tabletop umbrella, green iPod nearby, feet donning J. Crew flip-flops. A few miles away, Bulgarian Todor Markov, 29, watches children splash in a pool at the Marriott Wardman Park Hotel. Markov, who immigrated last year with the help of a relative who sponsored his U.S. residency, reclines in the deck chair contemplating when he will attempt the U.S. veterinary exam to make use of the degree he attained back home.