A periodontist is a dentist who specializes in the prevention, diagnosis, and treatment of periodontal disease, and in the placement of dental implants. Periodontists are also experts in the treatment of oral inflammation.
Ground speed. Ground speed is the horizontal speed of an aircraft relative to the ground. An aircraft heading vertically would have a ground speed of zero. Information displayed to passengers through the entertainment system often gives the aircraft ground speed rather than airspeed.
Tennis Court surfaces and their speeds is a topic that often confuses people, there's a ton of conflicting information and a lot of speculation about whether a surface is playing fast or slow. But is there a way to end all that and simple say for example Indian Wells is played on X and it plays at X speed.