Word: occurence
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Dates: during 1950-1959
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...live vaccines must be made with viruses that have no power to cause disease. A few occur that way in nature. Most are formerly virulent strains that have been "attenuated" by growing them in animals (or eggs) that are not their natural prey. These must then be tested to make sure that after being allowed to grow in the human digestive system they do not revert to virulent form. No such reversion to type has been detected in tests that have now covered more than a million subjects...
...scientists have known for some time that flares generally occur where there is a large concentration of sunspots, thought by Menzel to be "islands of intense calm floating in the otherwise turbulent sea of the Sun's atmosphere." Accordingly, the staff at Sacramento Peak had been watching a large cluster of sunspots covering over three billion square miles of the Sun's surface. Before the giant flare was seen, seven smaller flares had been observed, like rumblings before a storm. When a flare breaks out it spews a large number of electrically charged particles out into space; the bombardment...
...illustrated by these four lines. The top two plots show the acceleration of two earth satellites due to varying atmospheric density, over a period from April to December, 1958. The third graph is the intensity of solar radiation during the same period, and shows how peaks and troughs occur together on the three lines. The lower plot measures the angular position of the low point of the orbit and indicates a general trend...
...going to utilize the whole courtyard," Rinzler emphasized. "Even the roof of the Master's house is a stage." Action will occur on all sides of the audience, seated in the courtyard's center...
...children, the skin frequently shows wheals if stroked repeatedly in the same spot, but this sensitivity usually wears off. Among adults, dermographia may occur in either sex and show up as redness and swelling around the belt or girdle line, or under shoulder straps or suspenders. Antihistamines are generally effective in controlling the reaction, say the Little Rock doctors...