With some exceptions, an Employee is covered by the HCSO if the Employee works for an Employer covered by the HCSO and: 1  Is entitled to be paid the minimum wage; 2  Has been employed by the Employer for at least 90 calendar days; and. 3  Works at least 8 hours per week in San Francisco.
Vortex ring. Spark photography image of a vortex ring in flight. A vortex ring, also called a toroidal vortex, is a torus-shaped vortex in a fluid or gas; that is, a region where the fluid mostly spins around an imaginary axis line that forms a closed loop. The dominant flow in a vortex ring is said to be toroidal, more precisely poloidal.
What is the polar vortex? The polar vortex is an area of low pressure and cold air that swirls around both of the Earth's poles like a wheel. Sometimes the polar vortex wobbles and a lobe surges south, blanketing portions of North America with bitter temperatures. The chilly mass circulates around the North (and South) Pole all year long. In the winter, it weakens, sending cold air south with the jet stream.