Annual deaths from tornadoes, earthquakes and floods together total fewer than 200. The most deadly heat wave in recent years occurred in Chicago over a week in July 1995, when temperatures hovered around 100 degrees.
Cardiac Cycle: 1st Systole Phase. During the systole phase, the right ventricle receives impulses from the Purkinje fibers and contracts. The atrioventricular valves close and the semilunar valves open. The de-oxygenated blood is pumped into the pulmonary artery.
Hybrid contacts are large-diameter lenses that have a rigid gas permeable central zone, surrounded by a peripheral zone made of soft or silicone hydrogel material. The purpose of this design is to provide the visual clarity of GP lenses, combined with wearing comfort that is comparable to soft lenses.