Ensign Gabrielli was a Human man, a Starfleet officer in the 24th century. He was the tactical officer of the USS Anansi.
In 2375, Gabrielli prepared Ezri Dax for her mission to the Pandora facility to stop Axael Krinn. In the ship's armory, Gabrielli modified Ezri's commbadge (to boost the signal when she was in the facility, although the modification meant Ezri could only communicate with the USS Anansi and they could not contact her) and provided her with a small phaser, just the size of Ezri's little finger. (DS9 - Prophecy and Change short story: "Chiaroscuro")