So normally within several minutes, the voramino valley is closed. And normally within several hours, the ductus arteriosis is also closed. Now, in some situations, in some conditions, however, the fetus can develop a condition known as either the patent ductus arteriosis or the patent for Raymond O'Valley. And in both cases, what the patent means is we have an abnormality in which either one of these two ducts, either one of these two shuts do not actually close off. They remain open for the duration of that individual's lifetime unless it's actually surgically fixed. So let's begin by discussing the patent ductus arteriosis.