In addition, there's connecting service from Canada, Europe, South America and the Far East. Commuter service between San Juan, St. Croix and St. Thomas is also available. Commuter airlines can transport you between islands in as little as 17 minutes.n addition, there's connecting service from Canada, Europe, South America and the Far East. Commuter service between San Juan, St. Croix and St. Thomas is also available. Commuter airlines can transport you between islands in as little as 17 minutes.
A rough estimate is that it takes about 14 hours for blood to be broken down within the intestinal lumen; therefore if transit time is less than 14 hours the patient will have hematochezia, and if greater than 14 hours the patient will exhibit melena.
In medicine, melena or melÃ¦na refers to the black tarry feces that are associated with upper gastrointestinal bleeding. The black color is caused by the hemoglobin in the blood being altered by digestive chemicals and intestinal bacteria.