    Ð°Ð½ Obstetrician is a physician who has successfully completed specialized education and training in the management of pregnancy, labor, and the puerperium (the t â¦ ime-period directly following childbirth).n Obstetrician specializes in the care and treatment of pregnant women during their pregnancy, labor, delivery and the postpartum period.
Animal skins were used as sails for the earliest boats and rafts. The Egyptians and other ancient people wove reeds together in mats to make sails, but the Egyptians were also the first to make cloth sails as early as 3300 B.C. Great sailors of the Mediterranean region like the Phoenicians sailed under cloth sails.
Iron and steel slowly became the materials of choice because they require little repair. The first all-steel windmill and tower was produced by the United States Wind Engine & Pump Co. The first electricity-generating wind turbine was invented in 1888 in Cleveland, Ohio by Charles F. Brush. The turbineâs diameter was 17 meters (50 feet), it had 144 rotor blades made of cedar wood, and it generated about 12 kilowatts (kW) of power.