Reacción clásica a novedades científicas


La respuesta de los “conservadores” […] parece reflejar el esquema clásico de reacción inducido por las novedades científicas: no es cierto (primera fase); aunque sea cierto, es una cuestión secundaria (segunda fase); es cierto, pero yo ya lo había dicho (tercera fase).

Telmo PievaniRepensar a Darwin, Investigación y Ciencia, enero 2016

Power supply de una fuente de alimentación ATX de PC

Para trabajar con todo tipo de “inventos” es muy útil tener una fuente de alimentación. Las fuentes de ordenador de sobremesa se pueden adaptar de forma muy fácil para esto, y suministran (sin necesidad de hacer nada) diferentes voltajes:

  • +3.3 V
  • +5 V
  • +12 V
  • -12 V

(Combinando los anteriores podemos obtener otros voltajes, naturalmente).

Hay inifinidad de tutoriales por internet en el que explican cómo hacer esto, aunque relamente no hace falta un tutorial porque es cortar cables y listo.

Como puntos a destacar, para que arranque la fuente es necesario puentear el cable verde a cualquier cable tierra (negro). Y en función de lo antigua que sea la fuente será necesario añadir una resistencia o no; en mi caso no fue necesario.

Para hacer los agujeros en la cargasa recomiendo empezar con pequeños taladros y luego hacerlos más grandes.

Compré unos conectores como estos y estos los que realmente compré ya no los veo, pero hay miles)

Y para la próxima que me haga, las conexiones las voy a hacer con estas horquillas, que facilitará mucho la vida.

No hice muchas fotos durante el montaje, pero es que es muy básico todo…




Where are they?


Evolution has no destination. Each time you push the “go” button, you end up someplace different. Start things over on Earth (or another Earth-like planet) and not only would there be different species with perceptions and intelligences that vary wildly from our own, the very chemistry of life would be altered as well!

That’s conjecture – but it’s pretty safe conjecture. To see why, let’s do a quick back-of-the-envelope calculation.

Among other things, our DNA contains instructions for building proteins out of sequences of amino acids. For simplicity, let’s assume that life always evolves that same basic molecular machinery. There are 500 or so known amino acids, of which life on Earth uses only 23. Sticking with our KISS (keep it simple, stupid) approach, let’s assume all life uses those same 23.

The average protein in an eukaryotic (nucleus-containing) cell on Earth is about 450 amino acids long. There are therefore 23^450 (=10^613) different proteins of that length that the machinery of our DNA might construct. That’s a huge number! Not surprisingly, terrestrial life has stumbled upon uses for only a small fraction of those possible proteins – about 10 million.

So now let’s take those 10^613 possible proteins and split them into planet-proportioned groups of 10 million each. With no overlap at all, there would be 10^606 of those piles! There are no more than about 10^23 habitable planets in the entire observable universe. You could spread those stacks of proteins over the planets in 10^583 similar universes without having to duplicate a single protein on any two planets!

The takeaway is this: The likelihood that any two life-bearing planets in the universe share even remotely compatible biochemistry is effectively zero.


Jeff Hester. Astronomy Magazine, September 2016

Elon Musk digging tunnels to save the world’s congestion problem?

I don’t know if you follow Elon Musk (Tesla, SpaceX…) on Twitter. I do. A few weeks ago he twitted on his way to work -on a Tesla, I suppose- that he was exasperated with Los Angeles traffic, and wondered about boring a tunnel. A moment later he twitted again that he would do it.

It seems now that he’s taken seriously the idea, and this past weekend workers started excavating a test trench at SpaceX headquarters.

I’m somewhat confused about this: being Elon Musk the visionaire and entrepeneur he is in so many different areas (PayPal, Tesla, SpaceX, Hyperloop…) this shouldn’t surprise anyone. But this is civil engineering (tunnel boring) he’s talking now, and he even claims he wants to improve tunneling speed by 500 or even 1,000 percent! Although he did say: “We have no idea what we’re doing – I want to be clear about that” (!!!!???!!!)

What do you think? Is Elon Musk out of his depth this time? Will this new idea fail? Or if it works (I don’t know what innovative technology he wants to try out), will it work on all types of soils/rocks? Something deep in my cartesian/engineer mind tells me that it’s very difficult for someone with no previous (civil) engineering knowledge to suddenly come up with an idea that thousands of engineers and contractors all over the world are struggling with everyday. Or is it?

This is Elon Musk we’re talking about. They said the same things about him and the electric car or about launching rockets and landing them back again… And he proved them wrong. And what about the Hyperloop…? We’ll soon see.

Maybe he will fail in this new tunnel adventure, maybe he wont. But in any case this is exactly what the civil engineering world requires: out-of-the-(cartesian)-box thinking and people like Elon Musk with enough ingenuity -and money- to propose and experiment on new, world-changing ideas.

Let’s keep a close eye on Elon Musk’s latest idea, because it would indeed change our profession and the world!

More info:

Inside the ‘Tunnel’ Elon Musk Is Already Digging Under Los Angeles

Cita de Charles Babbage


On two occasions I have been asked (by members of Parliament!), “Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?” I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.

Charles Babbage (1791-1871), diseñador de la máquina analítica, precursora del ordenador.

Inventors and Inventions, Volume 1. Marshall Cavendish, 2007