    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.
In this construction, all of the crimp is in the warp and stretch in the fill direction is minimized. Polyester (DacronÂ®) Even though it was almost 40 years ago that Dacron replaced cotton as the primary sail material for fore and aft sails, it is a bit difficult to explain all the subtleties of this fabric. Dacron sail fabric has continued to develop since it was introduced in the mid-fifties.