The total force opposing LV con-. traction (i.e., the afterload) is the product of the LV. pressure and the internal surface area of the LV. cavity. In hypertensive subjects, of course, the arterial and. LV pressures are abnormally high during systole and, therefore, the LV afterload tends to be high.
Sincerely, Dick Montgomery A Most of the North American Hummingbirds migrate. The ones that go the farthest are the Rufous and the Ruby-throat. They may make trips to destinations which are as far as 2000 miles away.The hummingbird you have in northern Wisconsin is the Ruby-throated.n spring the birds probably follow the same route to come back north. A Ruby-throated Hummingbird flies at about 27 miles per hour if there is no tail wind or head wind. This would mean that long 500 mile flight across the Gulf of Mexico would take about 18 1/2 hours.
hummingbird migration-ruby-throated. Migration of the ruby-throated hummingbird has been an inspiration and a wonder and a scientific puzzle for years. Shrimp fishermen and workmen on oil rigs reported that they found ruby-throated hummingbirds far out in the Gulf of Mexico (100 and 200 miles) where they did not belong.nother study of ruby-throated hummingbirds has reported that when they gain 2 grams of fat, they have enough fuel to cross 600 miles of water without tailwinds. 8 So they eat in excess and wait for cold fronts to carry them on their way.