Las moléculas, localizadas en la membrana celular, actúan como una suerte de señal que induce la transición de las células embrionarias a células madre hematopoyéticas.
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Los riesgos de salud son mayores para las mujeres y las personas con niños pequeños y bebés.
Let's say it now, from the beginning (especially for the purists of the original authors of the inventors, if there is such a thing): six years before Gray and Bell developed it, the Italian Antonio Meucci already had the invention of the telephone. What he did Alexander Graham Bell, in reality, was to imagine a more organic infrastructure for such an invention.
Be that as it may, in addition to this invention, the photophone is more fascinating: It is actually a kind of light phone.
The light telephone
The photophone consisted of a mirror that reflects sunlight, mounted on a support that vibrates with the voice, so that the reflected light is received by a parabolic mirror and concentrated on a selenium cell that translates the signal into audible sound in a telephone receiver, as explained Santiago Alvarez in his book Of women, men and molecules:
Thus, the inventor of the telephone was also a precursor of the optical transmission of signals, which today we call photonics.
The photophone was patented December 18, 1880, but the quality of communication remained poor and the investigation was not continued by Bell. Still, shortly before his death, he told a reporter that the photophone was "the best invention [I've ever] made, bigger than the telephone."
Later this invention served as the basis for the development of communications using fiber optics and lasers.
Understanding the phenomenon of light reflection is another story. The theory of extromission defended by Euclid and Ptlemy, among others, maintained that light comes from the eyes of the observer. In the opposite sense, the theory of intromission (light enters through the eyes) was defended by Aristotle and rescued by Avicenna in the 10th century.
If you're still a little angry about the fact that Bell is unfairly credited with inventing the telephone (or even the photophone), then you might want to watch the following video, which shows that the idea of Author has something religious or romantic, as well as the idea of Inventor; and, that given the structure of the history of innovation in the world, we should begin to give less romantic importance to inventors or discoverers, and more to the ecosystems where such inventions and discoveries occur:
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The news
Although the telephone is one of Edison's best-known inventions, the photophone was much more fascinating.
was originally published in
Xataka Science
by
Sergio Parra
.
Proxima Centauri is one angry star.
A little more than Nepal's previous measurement and about four meters higher than China's: this is the new agreement about the altitude of Everest: 8,848.86 meters.
In 1856, the Great Trigonometric Survey Project established the first published altitude of Everest, then known as Peak XV, in 8840 meters. China and Nepal reached a consensus last year on jointly announcing the new height of the peak, and it is being made public now.
Everest height conflict
In 2005, China measured the mountain's altitude again and came up with a result of 8,844.43 meters. Thus began a discussion between China and Nepal that lasted five years. China argued that the measurement should be made up to the altitude of the rock, which is 8844 meters, but Nepal objected that it should be made up to the altitude of the snow, which is It is 8848 meters.
In 2010, both nations reached an agreement that the altitude of the mountain is 8,848 meters, and Nepal recognized China's claim that the altitude up to the rock of Everest is 8,844 meters. Now, in 2020, both countries have closed the matter with a commonly recognized height.
However, we should not confuse the highest point on Earth with the highest mountain in the world. This mountain is the Mauna Kea, is the Hawaiian Islands, which is 10,205 meters from its underwater base in the Hawaiian Depression to its summit. Of this total height, 4,205 meters are above sea level.
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The news
The new height of Mount Everest, the highest peak in the world, is 8,848.86 meters: China and Nepal agree
was originally published in
Xataka Science
by
Sergio Parra
.