Implicaciones de la Estearoil CoA Desaturasa en el cáncer

After some months of cold winter, spring had come, so Thoreau in this chapter tried to explain the different changes and transformations that he could observe around him. He described the pond’s thaw and the birth of a new landscape which was beautiful. For Thoreau this chapter was a kind of creation story because all nature began to show signs of new life. Obviously, one stage had finished, and another very different one was beginning.

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ROCÍO CUENCA O.

MAYRA LAZO T. 180

Spring came about the first of April, with little variation of temperature. It began to melt on the north side and in the shallower parts of the pond. During spring time the wind blew and agitated the water of the pond. A thermometer thrust into the middle of Walden stood at 32 º, and in the middle of Flint’s Pond, the same day, at 31 and a half at a dozen rods from the shore in shallow water, and under ice a foot thick, at 36º. That difference of three and a half degrees showed why the ice there broke up so much sooner than in Walden. At this time the ice in the shallowest part was several inches thinner than in the middle.

However, in midwinter the middle had been the warmest and the ice thinnest there. People who waded about the shores of the pond in a summer night knew how much warmer the water was close to the shore.

In spring, the sun reflected from the bottom of the shallow water, which had been the first to freeze in the fall,

warming the ice from both sides and creating a honeycomb effect, in which air bubbles helped to melt the ice. The sun in spring not only exerted an influence through the increased temperature of the air and earth, but its heat passed though ice a foot or more thick. Where there was a rock or a long rising near the surface, the ice over it was much thinner, and it was frequently quite dissolved by that reflected heat.

The phenomena of the year took place every day in the pond on a small scale. Every morning the shallow water was being warmed more rapidly than the deep. Every night it was being cooled more rapidly, until the next morning.

The night was the winter, the morning and evening were the spring and fall, and the noon was the summer. Over that time lapse the cracking and booming of the ice indicated the changes of temperature.

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ROCÍO CUENCA O.

MAYRA LAZO T. 182

One pleasant day after a cold night on Flint’s Pond, Thoreau realized with surprise that when he struck the ice with the head of his axe, it resounded like a gong for many rods around. The pond began to boom about an hour after sunrise, when it felt the influence of the sun’s rays slanting upon it from over the hills. It stretched itself and yawned like a waking man, with a gradually increasing tumult, which was kept up three or four hours. However, in the middle of the day, being full of cracks, and the air being less elastic, it had lost its resonance.

One attraction in coming to live to the woods, was that Thoreau had the opportunity to see the spring come, when the ice in the pond began to be honeycombed. Fogs, rains, and warmer suns were gradually melting the snow. Thoreau was on the alert for the first signs of spring to hear the chance note of some arriving bird or the striped squirrel’s

chirp. On March 13^th, when he had heard a bluebird, a song sparrow, and a red-wing, the ice was a foot thick.

One day, an old man who was a close observer of Nature told a little story to Thoreau. One spring day the man took his guns and his boat and went to catch ducks.

He stayed on the pond where there was still ice, but it was melting. It was a warm day, and he was surprised to see a body of ice remaining. Not seeing the ducks, he hid his boat on the backside of an island in the pond; then he concealed himself in the bushes on the South side, to await them there. Then he heard a distant sound. It seemed to him like the sound of a vast body of owls coming in to settle there.

Immediately he seized his gun and started up in haste. But, to his surprise, he found that the whole body of the ice had started to move while he was waiting and then had drifted in to the shore, and the sound he heard was produced by the edge of the ice grating on the shore.

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MAYRA LAZO T. 184

For Thoreau, every change he observed was very interesting: the ice melting, the green leaves in the trees, the songs of the birds, and the sun shining all the days.

Every detail was wonderful. During spring the pond seemed to be quiet sometimes, but at other times the waves moved as the wind passed by in any direction.

According to Thoreau, Nature was the mother of humanity. The earth was not a mere fragment of dead history. Nature was a place that offered the best things for men. The different vegetation, animals, and seasons of nature could be enjoyed by men. Without a doubt, it offered a different style of life with complete freedom. In the mornings, Thoreau liked to watch the geese swimming in the middle of the pond. After they had rested there, they flew away to the north. The pond appeared to be an artificial one for his amusement.

Finally, Thoreau was a man who enjoyed every day of his life at Walden, and who knew how to appreciate the gifts that nature offered. In this chapter he explained his experience of the birth of a new landscape which had interesting things.

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MAYRA LAZO T. 186