What You May See and Hear During Echocardiography. As the doctor or sonographer moves the transducer around, different views of your heart can be seen on the screen of the echo machine. The structures of the heart will appear as white objects, while any fluid or blood will appear black on the screen.
Ostracoderms (shell-skinned) refers to the armored jawless fishes of the Paleozoic. The term does not often appear in classifications today because it is paraphyletic or polyphyletic, and has no phylogenetic meaning.he microscopic layers of that shield appear to evolutionary biologists, like they are composed of little tooth-like structures.. Neil Shubin writes: Cut the bone of the [ostracoderm] skull openâ¦pop it under a microscope andâ¦you find virtually the same structure as in our teeth.
Osmium (from Greek á½ÏÎ¼Î® osme, smell) is a chemical element with symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with a density of 7004225900000000000â 22.59 g/cm3. Its alloys with platinum, iridium, and other platinum-group metals are employed in fountain pen nibs, electrical contacts, and other applications where extreme durability and hardness are needed.