(AP) — Advocates for closing the Guantanamo Bay detention center were hopeful when President Joe Biden took office. And they were relieved this summer as the U.S. released a prisoner. Many are now increasingly impatient. In the months since that release, there have been few signs of progress in closing the notorious offshore prison on the U.S. base in Cuba. That has led to growing skepticism about Biden’s intentions as the administration nears the end of its first year and the detention center reaches a milestone on Tuesday — the 20th anniversary of the day the first prisoners arrived.