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Pedro J. Hdez
Attended University of Manchester
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Pedro J. Hdez

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Un nuevo Sokal de la mala investigación científica en nutrición y su amplificación en los medios.

"My colleagues and I recruited actual human subjects in Germany. We ran an actual clinical trial, with subjects randomly assigned to different diet regimes. And the statistically significant benefits of chocolate that we reported are based on the actual data. It was, in fact, a fairly typical study for the field of diet research. Which is to say: It was terrible science. The results are meaningless, and the health claims that the media blasted out to millions of people around the world are utterly unfounded.

Here’s how we did it.2
“Slim by Chocolate!” the headlines blared. A team of German researchers had found that people on a low-carb diet lost weight 10 percent faster if they ate a chocolate bar every day. It made the front page of Bild, Europe’s largest daily newspaper, just beneath their update about the Germanwings crash. From there, it ricocheted around the internet and beyond, making news in more than 20 countries and half a dozen languages. It was discussed on tel...
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Evolución de la intensidad de CO2 de Alemania, Japón y EEUU comparada. Recordemos que la intensidad de CO2 no es más que las emisiones por unidad de energía generada.
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Compare power generation mix and related CO2 intensity in Germany, Japan and US (2007-13) http://bit.ly/1Af2IqT  
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Why democratic elections are always flawed

"The first is that voters are, quite rationally, rather ignorant about politics. Sensible people vote to express themselves or out of a sense of duty, not because they harbour the illusion that it might be their vote that swings the entire election. Quite sensibly, then, people who devote hours to researching a new phone will not waste time researching which party to support.

The second reason is Nobel laureate Ken Arrow’s “impossibility theorem”, one of the most celebrated and misunderstood results in economics. Arrow’s theorem is often described as showing that there is no voting system that will reflect what society truly prefers. Arrow actually showed something more profound: that it makes little sense to speak of what “society truly prefers”. That very idea is incoherent. And those who expect that a democratic election will ever give society what it “truly prefers” will have to get used to disappointment."
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Can Audi produce fuel from thin air? Sure. There is no question about technical viability. However, they are also not the first to make this claim.

It is important to note that because this process is an energy sink, it could exacerbate carbon dioxide emissions. The reason they are claiming it doesn’t is because they are assuming little to no carbon emissions from the inputs. That’s why the graphic stipulates that the electricity comes “entirely from renewable energy sources.”

So, circling back to the claim that “carbon-neutral diesel is now a reality” — I think most would agree that projections of what a process will look like after it has been scaled up 2 more times don’t constitute reality. They constitute a vision of reality. This claim is no more accurate than if I were to say “Colonies on Mars are now a reality.”
A look at the economics of Audi's new carbon-neutral diesel.
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One of the first general circulation models was developed at Lawrence Livermore National Laboratory by Cecil “Chuck” Leith in the early 1960s. Unlike the NOAA model mentioned above, Leith’s model only simulated the atmosphere. What make Leith’s work so remarkable was that he was the first to produce a computer animation based on the model output.
Columbia University climate scientist Kátia Fernandes appeared on the cover of the 2014 Climate Models wall calendar. The calendar, dreamed up by two science writers at Columbia University, offered a fresh look on the meaning of the term 'climate model.” Read more about the calendar from AGU's ...
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A compelling case for why countries should end subsidies for fossil fuels: It would save millions of lives.

"The arguments for cutting subsidies are not new. But the I.M.F.’s exhaustive research makes the case even stronger and more timely. The fund calculates that by raising taxes on fossil fuels, basically eliminating the subsidies, nations would reduce premature deaths caused by air pollution by 55 percent. That would make a big dent in the 3.7 million premature deaths that the World Health Organization links to all outdoor air pollution for just 2012".
Ending subsidies for fossil fuels would save many lives, a report from the International Monetary Fund makes clear.
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Taimyr wolf and the origins of dog

"There's an ongoing debate about where and when dogs originated. The when part might be closer to an answer now. Genetic drift is used by evolutionary biologist to try to recreate the lineage of species. The discovery of a 35,000-year-old wolf rib bone in the Taimyr peninsula in northern Siberia was the key to this story. The DNA from that bone suggests that it diverged from a common ancestor of present-day wolves and dogs near the beginning of the domestic dog lineage."
 
Taimyr wolf and the origins of dog
There's an ongoing debate about where and when dogs originated. The when part might be closer to an answer now. Genetic drift is used by evolutionary biologist to try to recreate the lineage of species. The discovery of a 35,000-year-old wolf rib bone in the Taimyr peninsula in northern Siberia was the key to this story. The DNA from that bone suggests that it diverged from a common ancestor of present-day wolves and dogs near the beginning of the domestic dog lineage. Their technique uses genetic drift of 'regular' DNA and mitochondrial DNA.

► Genetic Drift
There are non-lethal random mutations in DNA that survive to the next generation due to natural selection and sometimes due to 'luck'. Surviving by natural selection makes sense, a mutation affords an advantage so that offspring should excel and survive. Genetic drift is when a mutation doesn't necessarily result in an advantage but is nevertheless passed on 'by chance'. Tracing these mutations help create a lineage for evolutionary biologists.

► Mitochondrial DNA vs. Nuclear DNA
Mitochondria are the energy power plants inside cells. They have a few genes necessary for oxidative phosphorylation, which is a fancy term for making energy. The nucleus of the cell is where the chromosomes are. Nuclear DNA is the DNA that you hear about in the news, for example in forensic science. In the figure below, you can see that mitochondrial DNA is passed on only by the mother while nuclear DNA is passed along by both parents. Genetic drift in mitochondrial DNA is much slower and helps refine the lineage of a species. It is slower because it is only inherited by half of the genetic source, i.e., the mother.

You can read a summary of the article in layman's terms here:
Arctic find confirms ancient origin of dogs
http://news.sciencemag.org/biology/2015/05/arctic-find-confirms-ancient-origin-dogs

Full article and source of the very cool graphical abstract:
Ancient Wolf Genome Reveals an Early Divergence of Domestic Dog Ancestors and Admixture into High-Latitude Breeds
Skoglund et al
Current Biology May 2015
http://www.cell.com/current-biology/abstract/S0960-9822(15)00432-7

Source for the mitochondria DNA figures:
University of California Museum of Paleontology's Understanding Evolution (http://evolution.berkeley.eduhttp://goo.gl/WZgKRV

A bit more reading:
How the wolf became the dog (full article behind paywall)
http://news.sciencemag.org/environment/2015/04/how-wolf-became-dog

Late for #FidoFriday  but always on time for #ScienceEveryday  
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Pedro J. Hdez

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Do We Need To Go Nuclear On Climate Change?

“When renewables are expensive, people want to find ways to bring costs down, [but] when nuclear is expensive, people see cost as a reason to reject the technology,” noted Ken Caldeira, the atmospheric scientist and one of the co-authors of the 2013 open letter arguing for further development of nuclear power. “I would think some combination of innovation and more sensible regulations could bring costs down in the nuclear sector.”

Caldeira also suggested that those hoping wind and solar power alone might deliver the world from runaway greenhouse gas emissions are fooling themselves.

“From the position of physical possibility, sufficient power could be delivered without nuclear,” Caldeira said. “In the real world, with technical, economic, and political constraints, it seems highly unlikely that society can stabilize climate without nuclear power.

“The question is not ‘What is possible?’” he added, “but ‘What is feasible?’ or ‘what is achievable given real world constraints?’”

Via https://www.facebook.com/MichaelMannScientist
"Climate change is the biggest environmental challenge of our time," Yukiya Amano, head of the Vienna-based International Atomic Energy Agency, told French ministers at a meeting in Paris on Wednesday. "As governments around the world prepare to negotiate a legally binding, universal agreement on climate at the United Nations Climate [...]
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Maravilloso ejemplo de cómo a veces la economía es sólo un poco de prestidigitación.

How Fake Money Saved Brazil

"In the early 1990s, Brazil had suffered almost two decades of crippling inflation. Expectations were that the government was helpless to stop it, and that absolutely nothing could be done. Which meant that, in practice, nothing could be done: every lever that the central bank could reach had been pulled, leaving the government helpless to treat the problem, even by exceptional means. 

So the government abandoned the cruzeiro and adopted the CRV, a unit of "real value." Unfortunately, as any economist will tell you, there is no "unit of real value.*" The only measure of value is what people will pay. But the CRV worked nonetheless.

Here's the catch: the Brazilian government didn't print any CRVs. They just required prices to be printed in CRVs, and posted a CRV-to-cruzeiro exchange rate. And so, when people went to the store, they just paid in cruzeiros. The fundamentals of the economy were just as sound or unsound as they were before, but people saw a number -- a measure of "real value" -- which was stable, month after month.

And so inflation stopped. Not because of some bold, decisive central-bank action or leadership by the government. Because Brazilians were lied to, and everyone lived happily ever after."

See also c http://www.npr.org/sections/money/2010/10/04/130329523/how-fake-money-saved-brazil
 
On the face of it, this is ridiculous: Venezuela's runaway inflation has nothing to do with the United States, Europe, Google, or Mozilla. 

But it's not like this hasn't worked before.

Under normal economic conditions, inflation is driven by both (a) economic fundamentals, and (b) expectations about inflation in the future. You can fix the former problem by removing price controls, selling debt onto the open market and burning the resulting money, or fiddling with your foreign reserves. Under exceptional circumstances, however, inflation is mostly about expectations about inflation: because you believe that your money will be worth less in the future, you'll spend it now, resulting in an escalating bidding war for all goods on the market.

You can fix this by lying. 

In the early 1990s, Brazil had suffered almost two decades of crippling inflation. Expectations were that the government was helpless to stop it, and that absolutely nothing could be done. Which meant that, in practice, nothing could be done: every lever that the central bank could reach had been pulled, leaving the government helpless to treat the problem, even by exceptional means. 

So the government abandoned the cruzeiro and adopted the CRV, a unit of "real value." Unfortunately, as any economist will tell you, there is no "unit of real value.*" The only measure of value is what people will pay. But the CRV worked nonetheless.

Here's the catch: the Brazilian government didn't print any CRVs. They just required prices to be printed in CRVs, and posted a CRV-to-cruzeiro exchange rate. And so, when people went to the store, they just paid in cruzeiros. The fundamentals of the economy were just as sound or unsound as they were before, but people saw a number -- a measure of "real value" -- which was stable, month after month.

And so inflation stopped. Not because of some bold, decisive central-bank action or leadership by the government. Because Brazilians were lied to, and everyone lived happily ever after.

Sure, Venezuela is corrupt and mismanaged and blames foreigners for self-inflicted problems. But all other issues aside, banning truthful information on the state of their currency isn't just a doomed attempt to protect its leaders' political fortunes: it's a doomed attempt to protect its leaders' political fortunes which, if successful, might actually solve the problem.
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Shadow work, el segundo trabajo que no sabes que tienes y su efecto en la economía.

Vía @cienciabolsillo
Technology has knocked the bottom rung out of the employment ladder, which has sent youth unemployment around the globe skyrocketing and presented us with a serious economic dilemma. While many have focused on the poor state of our educational system or the “jobless” recovery, another, overlooked factor behind this trend is the phenomenon...
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De las renovables, sólo la solar fotovoltaica está en la senda de crecimiento necesaria para el objetivo del escenario que limita el aumento de la temperatura media global a 2ºC.
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Renewable power generation by technology (2000-25) - 2° Scenario targets http://bit.ly/1Af2IqT
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The case for nuclear power

This article is part of The Conversation’s worldwide series on the Future of Nuclear. You can read the rest of the series here [https://theconversation.com/au/topics/future-of-nuclear-series], and a counterpoint to the views expressed in this article here [https://theconversation.com/accidents-waste-and-weapons-nuclear-power-isnt-worth-the-risks-41522]
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Education
  • University of Manchester
    MSc, 1992 - 1993
  • ULL
    Física/Astrofísica, 1986 - 1991
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