Los que crecen a más de 160 metros de profundidad establecen simbiosis con un alga filamentosa capaz de aprovechar la poca luz que llega.
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One of the most widespread urban legends around the world of public swimming pools is, along with the fact that if you pee a chemical product diluted in the water changes color and gives you away to others, that If you ejaculate in the water, it is possible to get a girl who splashes nearby pregnant.. Don't worry: you can urinate and ejaculate in a public pool without any of those worries (although of course it's better that you don't do it for everyone's sake).
And semen, for those who do not want to get pregnant, It turns out something like a substance contaminated by radioactivity. There are women who can't even tolerate it rubbing against their skin: what if, by mistake, it ends up entering the vagina? What if there are jumping sperm?
To take away some of the fear about semen, well, it is worth knowing how long is a sperm capable of surviving when it leaves our body in the race of life (being very euphemistic).
Sperm do not get along very well with vaginas
Ironically, sperm don't get along very well with vaginas. More than 99 % of sperm in ejaculate They die in the vagina before reaching the fallopian tubes., given the acidic environment of the vagina. Therefore, a man who has less than 20 million sperm per ejaculation is considered infertile.
After entering the woman's body, the sperm usually remains fertile between 48 and 72 hours, but only in ideal conditions, that is, during the days of ovulation, which is when the vaginal pH is above 6, which is the pH during the rest of the days (the degree of acidity of the ideal environment for a sperm is 7-7, 5, and the temperature: between 37 ºC and 37.5 ºC.)
There are other factors that could influence the fate of the sperm. The work carried out by British researchers Robin Baker and Mark A. Bellis, although not yet conclusive, suggest that orgasm offers women a way to control male sperm. If there is an orgasm, more sperm is attracted. If there is not, it is repelled to some extent. If the orgasm occurs under the circumstances of infidelity, then the orgasm produces a greater number of contractions to attract a greater flow of sperm: why else would you run the risk of maintaining an extramarital relationship? Something like the effect of unblockers on drains. The cervix literally sucks.
If we ejaculate outside the vagina, the life expectancy of the sperm is very short. Depending on humidity and temperature, They can last only minutes. How long it takes for the seminal fluid to dry, which is where the sperm can survive.
By the way, spermatozoa were first distinguished in 1679 by Antoni van Leeuwenhoek, inventor of the first powerful microscopes.
More information | The world | Very interesting
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The news
What is the life expectancy of a sperm after ejaculation?
was originally published in
Xataka Science
by
Sergio Parra
.
Pessimism finds great acceptance in all social classes because it feeds our natural tendency to distrust the new, advances of any kind, luddite style mode.
And that prevents us from fully understanding how innovation affects not only our lives, but the effects of the innovation itself. He talks about this and other things the new book of Matt Ridley: Keys to innovation.
Serendipity and context
One of the great sources of scientific discovery is serendipity.: the scientist pursues a goal and, along the way, by pure chance, finds something he did not expect, which ends up becoming his main discovery.
In the same way, scientific discovery is not customizable: it works in waves that cover nations or cultures, waves that are more or less intense and rich depending on political, cultural or ideological issues. Because inventions are nothing more than materialized ideas. And ideas fly from head to head like viruses. And ideas have no owner: ideas are reformulations of other ideas that we borrow.
Keys to innovation (Guesses)
And that's what Ridley talks about, relying not only on encyclopedic documentation, but also narrating it like good storytellers: making us participate in each small advance on the long ladder of innovation.
Innovation is the most important activity of our time: it brings spectacular progress to our standard of living, but also, at times, disturbing changes to society. Matt Ridley understands innovation as a haphazard process that advances from the bottom up and is a direct result of the human habit of exchange, and not as an orderly process that is set in motion from the top according to an established plan. It is always a collective, collaborative phenomenon, which involves trial and error, and is never the creation of a solitary genius. The author draws these and other conclusions from the fascinating history of numerous advances that illustrate what innovation is and what mechanisms drive it.
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The news
Books that inspire us: 'Keys to Innovation' by Matt Ridley
was originally published in
Xataka Science
by
Sergio Parra
.
El estudio de atletas de élite ayuda a identificar las consecuencias de la actividad física intensa.
Los muones y los electrones podrían no experimentar las mismas interacciones fundamentales, en contra de lo que predice el modelo estándar.
Se desconoce todavía el propósito exacto de este rasgo biológico cambiante.
The great leap towards civilization, prosperity, increased life expectancy and other recent milestones is not due, at least not directly, to the scientific revolution of Galileo and Newton, since most of the life-changing innovations of people hardly relied on new scientific knowledge (at least in principle), and few innovators who brought about these changes had scientific training.
In the opinion of the specialist in economic history Deirdre McCloskey, which has given most of us a better life It is due to "innovationism". Sliced bread is a good example of this.
Precedents of science
According to McCloskey, innovationism would be the tendency or habit to apply new ideas to raise the standard of living. And many innovations preceded the science on which they were based (Newcomen, inventor of the steam engine, or Arkwright, promoter of the textile revolution, or Stepehenson, father of the railroad, were men with little academic training and humble origins).
![[Libros que nos inspiran] 'El optimista racional' de Matt Ridley: ¿tiene límites la capacidad de progreso de la especie humana?](https://i.blogs.es/933b0c/portada-optimista-racional_med/375_142.jpg)
Later, science would contribute to the increasing pace of invention, and the line between discovery and invention would become more blurred, but deductive thinking hardly had any impact in the early years of the industrial revolution, a time when philosophers of science were scarce. nature.
He bread is an interesting example in that sense: a way to cut bread automatically to make standardized sandwiches. This breakthrough took place in 1928, and in a small American town, Chillicothe, in Missouri, as explained Matt Ridley in his book The keys to innovation:
Many people tried to invent a machine to cut and package bread into slices, but it worked poorly or the bread became stale because it was not packaged well.
He got it Otto Frederick Rohwedder for one crucial detail: he had to invent both the electric bread slicing machine and automatic bread packaging to prevent the slices from becoming hard. The rest was a stroke of luck. Chance, in innovation, is crucial, but that type of chance only occurs in certain ecosystems.
Innovation arises when there is freedom to think, experiment and speculate. It happens when there is freedom to trade. It appears when people enjoy a certain prosperity and are not desperate. It's somewhat contagious. It needs investment. It usually occurs in cities.
A good series to understand all the implications about innovation, and also those who resist them, whether they are Luddites, postmoderns or Malthusians, is the manga and anime Dr.Stone: a whole hymn to the virtues of Illustration. One of the characters, in fact, is a shaman fond of magic who will finally discover that science is much more powerful, but that innovation is what really makes the world worthwhile because it helps heal the wounded, allows see the short-sighted or help... make cotton candy or a cola drink. You can see more about this series in the following video:
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The news
Sliced bread and "innovationism", not science, is what allows us to prosper as a civilization
was originally published in
Xataka Science
by
Sergio Parra
.
At the University of Cambridge, more than 80 % of more than 1,500 employees voted in favor of a motion to replace a university policy that requires 'respect' for beliefs.
This puts us on the track that academics in the social sciences and humanities (SSH) in the United States, Canada and Great Britain also have an orientation towards freedom of expression stronger than many conservatives or moderate observers assume.
Under some assumptions
Most academics in the United States, Britain and Canada do not support firing academics who are politically incorrect, according to a new report from the Center for the Study of Partisanship and Ideology (CSPI).
The database of cancellations from the National Association of Academics records 65 campaigns against academics in 2020, a sharp increase from the 12-13 reported during 2018 and 2019. How much support is there for such actions among academics?
To find out, academics and doctoral students were asked on four hypothetical scenarios. These included one academic whose work found that 'greater ethnic diversity leads to greater social tension and worse social outcomes', a second where the researcher claimed that 'the British empire did more good than harm', a third in which ' children do better when they have two biological parents than single or adoptive parents', and a quarter where 'a higher proportion of women and ethnic minorities in organizations correlates with lower performance'.
Finally, subjects were asked whether a staff member who favored less immigration should be encouraged to find another job.
The results of 706 American SSH scholars are shown in the first table. This data shows that in most cases, only 7-8 percent of academics supported cancellation. Only in the case of the performance question was there a higher proportion, but even here it only reached 18 percent. British and Canadian findings were almost identical.
More broadly, when asked whether they prioritize social justice or academic freedom, 56 percent of American SSH scholars answered academic freedom and only 28 percent said social justice, with the rest unsure. The Canadian results were similar. However, among doctoral students surveyed in a primarily American sample, 40 percent supported social justice versus 34 percent in favor of academic freedom.
Therefore, while most academics do not support cancel culture, many do not oppose it either.
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The news
The majority of academics do not support cancel culture even if the researcher is politically incorrect (with nuances)
was originally published in
Xataka Science
by
Sergio Parra
.
Estudios con gemelos demuestran que la educación autoritaria y severa fomenta la conducta antisocial en la descendencia.
En el tejido cerebral post-mortem, astrocitos y microglía incrementan su actividad, mientras las neuronas se degradan.