The history of the modern world is a record of highly varied activity, of incessant change, and of astonishing achievement. The lives of men have, during the last few centuries, increasingly diversified, their powers have greatly multiplied, their powers have greatly multiplied, their horizon been enormously enlarged. New interests have arisen in rich profusion to absorb attention and to provoke exertion. New aspirations and new emotions have come to move the soul of men. Amid all the bewildering phenomena, interest, in particular, has stood out in clear and growing pre-eminence, has expressed itself in a multitude of ways and with an emphasis more and more pronounced, namely, the determination of the race to gain a larger measure of freedom than it has ever known before, freedom in the life of the intellect and spirit, freedom in the realm of government and law, freedom in the sphere of economic and social relationship. A passion that has prevailed so widely, that has transformed the world so greatly, and is still transforming it, is one that surely merits study and abundantly rewards it, its operations constitute the very pith and marrow of modem history.
Not that this passion was unknown to the long ages that proceeded the modern periods. The ancient Hebrews, the ancient Greeks and Roman blazed the was leaving behind them a precious heritage of accomplishments and suggestions and the men who were responsible for the Renaissance of the fifteenth century and the Reformation of the sixteen century contributed their imperishable part to this slow and difficult emancipation of the human race. But it is in modern times the pace and vigour, the scope and sweep of this liberal movement have so increased unquestionably as to dominate the age, particularly the last three centuries that have registered great triumphs of spirit.
In what epochs of modern history have men especially contributed to the emancipation of human race?
On January 3, 1961, nine days after Christmas, Richard Legg, John Byrnes, and Richard McKinley were killed in a remote desert in eastern Idaho. Their deaths occurred when a nuclear reactor exploded at a top-secret base in the National Reactor Testing Station (NRTS). Official reports state that the explosion and subsequent reactor meltdown resulted from the improper retraction of the control rod. When questioned about the events that occurred there, officials were very reticent. The whole affair, in fact, was discussed much, and seemed to disappear with time.
In order to grasp the mysterious nature of the NRTS catastrophe, it help to know a bit about how nuclear reactors work. After all, the generation of nuclear energy may strike many as an esoteric process. However, given its relative simplicity, the way in which the NRTS reactor functions is widely comprehensible. In this particular kind of reactor, a cluster of nine-ton uranium fuel rods are positioned lengthwise around a central control rod. The reaction begins with the slow removal of the control ro, which starts a controlled nuclear reaction and begins to heat the water in the reactor. This heat generates steam, which builds pressure inside the tank. As pressure builds, the steam looks for a place to escape. The only place this steam is able to escape is through the turbine. As it passes through the turbine on its way out of the tank, it turns the giant fan blades and produces energy.
On the morning of January 3, after the machine had been shut down for the holidays, the three men arrived at the station to restart the reactor. The control rod needed to be pulled out only four inches to be reconnected to the automated driver. However, records indicate that Byrnes yanked it out 23 inches, over five times the distance necessary. In milliseconds the reactor exploded. Legg was impaled on the ceiling; he would be discovered last. It took one week and a lead-shielded crane to remove his body. Even in full protective gear, workers were only able to work a minute at a time. The three men are buried in lead-lined coffins under concrete in New York, Michigan, and Arlington Cemetery, Virginia.
The investigation took nearly two years to complete. Did Byrnes have a dark motive? Or was it simply an accident? Did he know how precarious the procedure was? Other operators were questioned as to whether they knew the consequences of pulling the control rod out so far. They responded “Of course! We often talked about what we would do if we were at a radar station and the Russians came.
“We’d yank it out.”
Official reports are oddly ambiguous, but what they do not explain, gossip does. Rumors had it that there was tension between the men because Byrnes suspected the other two of being involved with his young wife. There is little doubt than he, like the other operators, knew exactly what would happen when he yanked the control rod.
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Fleas are perfectly designed by nature to feast on anything containing blood. Like a shark in the water or a wolf in the woods, fleas are ideally equipped to do what they do, making them very difficult to defeat. The bodies of these tiny parasites are extremely hardy and well-suited for their job.
A flea has a very hard exoskeleton, which means the body is covered by a tough, tile-like plate called a sclerite. Because of these plates, fleas are almost impossible to squish. The exoskeletons of fleas are also waterproof of fleas are also waterproof and shock resistant, and therefore fleas are highly resistant to the sprays and chemicals used to kill them.
Little spines are attached to his plate. The spine the flea scurries through an animal’s fur in – search of grooming pet tries to pull a flea off through the hair coat, these spines will extend and stick to the fur like Velcro.
Fleas are some of the best jumpers in the natural world. A flea can jump seven inches, or 150 times its own length, either vertically or horizontally. An equivalent jump for a person would be 555 feet, the height of the Washington Monument. Fleas can jump 30,000 times in a row without stopping, and they are able to accelerate through the air at an incredibly high rate – a rate which is over ten times what humans can withstand in an airplane.
Fleas have very long rear legs with huge thigh muscles and multiple joints. When they get ready to jump. They fold their long legs up and crouch like a runner on a staring block. Several of their joints contain a protein called resilin, which helps catapult fleas into the air as they jump, similar to the way a rubber band provides momentum to a slingshot. Outward facing claws on the bottom of their legs grip anything they touch when they land.
The adult female flea mates after her first blood meal and begins producing eggs in just 1 to 2 days. One flea can lay up to 50 eggs in one day and over 2,000 in her lifetime. Flea eggs can be seen with the naked eye, but they are about the size of a grain of salt. Shortly after being laid, the eggs begin to transform into cocoons. In the cocoon state, fleas are fully developed adults, and will hatch immediately if conditions are favorable. Fleas can detect warmth, movement, and carbon dioxide in exhaled breath, and these three factors stimulate them to emerge as new adults. If the flea does not detect appropriate conditions, it can remain dormant in the cocoon state for extended periods. Under ideal conditions, the entire life cycle may only take 3 weeks, so in no time at all, pets and homes can become infested.
Because of these characteristics, fleas are intimidating opponents. The best way to control fleas, therefore, is to take steps to prevent an infestation from ever occurring.
Using the information in the passage as a guide, it can be concluded that