By The Associated PressThe government is urging creditors to "remain patient and show compassion" for hundreds of thousands federal workers who remain furloughed without a paycheck. Some agencies are offering employees a cover letter that explains to creditors that the shutdown is "beyond on our employees' control and they will be returned to pay status as soon as possible." But financial impact of the shutdown goes far beyond the federal workforce. Local tourism businesses, for example, are losing millions because some national parks are still closed. And at research centers, some work has stopped. Included in that research: Children's Hospital in Pittsburgh had to suspend a study of how long children with urinary tract infections really needed to take antibiotics. Researchers are turning away calls from emergency rooms and pediatricians seeking to enroll more of their patients in the study, which if it works could mean fewer side effects for kids â¿¿ and possibly decrease antibiotic resistance as well, , said Dr. Alejandro Hoberman, the hospital's vice chairman of research. Why? Furloughed workers at the National Institutes of Health were responsible for some safety oversight. "This is a setback," he said, saying he feels growing frustration with the shutdown's trickle-down impact. "It could take months or longer" to get back on track. Among the other services affected by the shutdown: TRAVEL Federal air traffic controllers remain on the job and airport screeners continue to funnel passengers through security checkpoints. Furloughs of 2,900 Federal Aviation Administration inspectors had put safety oversight of planes, pilots and aircraft repair stations on hold, but the FAA later recalled about 800 employees â¿¿ including some inspectors â¿¿ to work. The State Department continues processing foreign applications for visas and U.S. applications for passports, since fees are collected to finance those services. Embassies and consulates overseas remain open and are providing services for U.S. citizens abroad.