Archive for the 'General Science' Category

Jun 21 2018

Iceman Update

Published by under General Science

In 1991 the mummified remains of a 5,300 year old man were found in the Alps on the border of Italy and Austria. The Iceman, also referred to by the nickname, Ötzi (because he was found in the Ötzal mountains) has been the subject of endless study ever since. He represents our best single window into copper-age society.

Scientists continue to learn more and more about Ötzi, what he ate, how he died, what he was doing in the hours before his death, and about the tools he had with him. Recently scientists have published a detailed report looking at the lifecycle of Ötzi’s tools, providing yet more insight.

Before we get to the new info – here is a quick summary of some basic facts about Ötzi. We know that he was shot in the back by an arrow. The arrowhead remains, in fact, in his back as smoking-gun evidence of the cause of death. Amazingly, the presence of the arrowhead was missed on X-rays of Ötzi for years – a great example of inattentional blindness.

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Jun 14 2018

New Review of Antarctic Ice

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A new review of the past few decades of satellite data published in the most recent edition of Nature tells the story of what is happening to ice on Antarctica. The result is probably exactly what you think – the ice is melting, at an accelerating rate. But the details are interesting.

First, we should note that Antarctica is a continent. There is land under all that ice, unlike the Arctic which is floating ice without any land. This makes a huge difference. While Arctic ice melts, the water fits exactly into the space previously displaced by the ice, so does not result in any sea-level rise. There are other effects to be concerned about, such as the effect on ecosystems and the effects of all that fresh water melting into the North Atlantic.

When ice sitting on top of land melts, however, that is new water finding its way to the sea, resulting in direct sea-level rise. As water gets warmer, it also expands, which further causes sea level rise. Also, the weight of all that ice pushes down the land, and when the mass of that ice decreases the land actually lifts up a bit.

The Antarctic ice system is also more complex than the Arctic. There are different glacier systems, which terminate at the ocean, and then there is the surrounding sea ice. There are several ways to estimate the extent of ice also, not just land coverage. Scientists need to also measure the thickness of the ice, the relationship between land and sea ice, the weight of the ice (the gravity it produces), and look at the under side of the glaciers that can erode away from warm sea water.

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Jun 08 2018

Séralini Fails Replication

Published by under General Science

Gilles-Éric Séralini is a French researcher who came to fame from publishing a study in 2012 claiming that herbicide-tolerant GMO corn, with or without combination with glyphosate herbicide, increased tumor risk in rats. He used this study to call into question the safety of GMOs generally, and to call for long term feeding studies. His results were embraced by the anti-GMO crowd, and to this day are cited as evidence GMOs are not safe.

One small problem, however, is that Séralini’s study was terrible. It immediately came under intense criticism. Specifically, the study had small sample size, and used a strain of rats known to have a high background rate of tumors. The data, therefore, was full of noise and was essentially uninterpretable. This is probably the reason for the lack of statistical analysis – because there were no significant findings. For these reasons in 2013 the study was retracted. In 2014 the paper was republished in a new open-access journal,  Environmental Sciences Europe, without additional peer-review.

It is pretty clear that Séralini is anti-GMO, and this likely biased his research. But regardless, the study methodology is terrible and the results worthless. But it did serve its (what I believe to be its true) purpose – to stoke fears about GMOs and to provide published “scientific” evidence to support the claims of anti-GMO activists.

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Feb 08 2018

Did a Comet Kill the Mammoths

Published by under General Science

Between 12,800 to 11,500 bp (before present) there was a cold period in North America called the Younger Dryas – named after the dryas flower whose pollen is a good marker for such cold periods. During this time the megafauna of North America, including the Mammoth, largely died out. Along with them went the Clovis culture – a big game hunting culture with distinctive stone points.

What caused this period of climate change and mass extinction?

This is a genuine scientific controversy. One group of scientists believe that the melting glaciers dumped fresh water into the northern Atlantic, temporarily shutting down the ocean currents that bring warm water to North America. Another group think that a comet impact is to blame.

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Jan 30 2018

Gattaca

Published by under General Science

The Human Genome Project was started in 1990 and completed in 2003. It took 13 years, multiple labs around the world, and hundreds of millions of dollars to sequence the human genome – this was more than two years ahead of schedule and millions of dollars under budget.

The reason for exceeding expectations is that the technology for sequence the genome was not static – it progressed throughout the project. DNA contains a code of four letters, the nucleotides indicated by the letters G, T, A, and C. This four-letter alphabet creates 64 different three-letter words, which code for different amino acids or operations that control the conversion of the code into proteins. Sequencing the genome essentially consists of discovering the order of these four letters in the string of a DNA molecule.

In 1997 the movie Gattaca, right in the middle of the genome project, portrayed the near future in which a cheek swab would rapidly yield an individual’s genome. It turns out this is not far fetched at all – we are almost living in Gattaca’s near future, at least in terms of sequencing technology. Scientists have just published a report of the nanopore device, which is a hand-held device capable of sequencing an individual’s genome.

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Jan 29 2018

Shameless Organic Fearmongering

Published by under General Science

I and others have long pointed out that anti-GMO fearmongering was largely created by the organic food lobby as a way of smearing their competitors. The strategy is simple – scare people way from genetically modified organisms (GMOs) and offer organic products as a non-GMO alternative. This is nothing new in advertising, create a fear and then offer your product as a safe haven.

A recent video posted by Stonyfield Organic makes the connection between anti-GMO fearmongering and buying organic explicit, as the screen capture shows.

There are many problems with this short video, not the least of which is that they use young girls to parrot their anti-science. Clearly not aiming for subtlety, the first girl declares that GMOs are “monstrous.” To apparently explain what she means, the second girl says that, “They take a gene from a fish and put it into a tomato.”

No, “they” don’t.

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Jan 18 2018

The Dangers of Celebrity Culture

Zooey Deschanel has a Facebook page where she gives advice on complex scientific topics. I love Deschanel as an actress and enjoy much of her work (particularly the otherwise mediocre movie version of the Hitchhiker’s Guide), but that does not mean I want to take advice from her on which foods I should eat.

Celebrity culture, in one form or another, has always been part of human society. Even chimpanzees will follow a charismatic leader, and it seems likely that humans are wired also to follow those we admire, and elevate them perhaps a bit too much. There is even research that shows that when we listen to a charismatic speaker the executive function part of our frontal lobes shuts down. We literally turn off our critical thinking when basking in the glow of our glorious leader.

Recognizing that this is part of the human condition is important. First, we need to be vigilant about surrendering our thinking to others. It’s also important to remind ourselves that everyone is a flawed human, and so constantly give those pedestals a reality check.

But that does not meant we should not admire and respect those who deserve it, or even look up to them for wisdom (as long as we maintain our critical eye). It does mean we need to choose carefully those we respect and follow.

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Dec 22 2017

Science in 2017

Published by under General Science

Science continues to kick ass in 2017, despite the fact that it often feels as if our species can’t get out of our own way. Obviously we need to keep our eye on important social and political issues, but it is reassuring to realize that there are many scientists quietly working away in their labs, clinics, observatories, or wherever to nudge our collective knowledge forward.

Here are some of the science news stories from 2017 that I think deserve notice and give us a good indication of what is to come.

The Age of Genetic Engineering

Genetic engineering is nothing new, but we seem to be on the upswing of an exponential curve with this technology. In recent years CRISPR has provided cheap and fast genetic manipulation, resulting in an explosion of research and potential applications. The technology borrows a system from bacteria used in their immune defense against viruses. It allows for the specific targeting of sequences of DNA which can then be clipped out and even replaced.

CRISPR technology continues to advance on two main fronts – improving the technology itself, and finding applications for it. This year researchers discovered how to adjust the specificity of CRISPR targeting – making it slower but more precise as desired. As powerful as this tech is, we are still on the steep part of the curve and it continues to improve. Continue Reading »

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Dec 14 2017

Antarctic Ice

Published by under General Science

Perhaps one of the most underrated science stories of 2017 was the separation of a massive iceberg the size of Delaware from the Larsen C Ice Shelf in Antarctica. That is because this is not an isolated event, but just a dramatic part of a larger story – the melting of Antarctica.

Antarctica contains most of the ice on Earth (90%). Much of that ice sits on top of land, unlike Arctic ice which is floating. When floating ice melts it just fills the space that it had displaced. There is a little bit a sea rise due to rising temperatures – water expands as it warms. But this amount of sea rise is small overall. When ice that was sitting on land flows into the ocean, it raises the sea level more significantly.

Antarctica is comprised of glaciers sitting on top of the continent, which itself is mostly below sea level. These glaciers are as thick as three miles. They are divided into a western glacier system and an eastern glacier system. West Antarctica, which is melting faster, contains enough ice to raise the sea level by 14 feet. East Antarctica is more stable but still showing some early signs of melting. All the ice here could raise the sea level by 175 feet.

As the glaciers melt during the warmer months they follow channels out to the ocean. These channels, however, are blocked by ice shelves, which act like a cork, keeping back the ice and helping to maintain the stability of the glaciers.

The ice shelves themselves have a certain structure – they rest on the sea floor but as they extend out from the continent eventually the ice lifts off the sea floor (called the grounding point) and as the ice extends out further it is floating on top of the water. The breakup of these ice shelves is a concern, because that would essentially remove the stopper and greatly accelerate the rate at which glacier melt finds its way to the ocean.

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Dec 05 2017

Plastic Waste

Published by under General Science

I know, there are already so many things to worry about. It’s almost painful to hear about one more way in which we may be harming the world. Such reports are also often couched in emotional and dramatic terms.

However, it’s important to sift through the rhetoric and evaluate what the science says about what is actually going on. There is increasing reporting about the coming plastic apocalypse. We are dumping massive amounts of plastic into the environment, and some of that plastic is winding up in the world’s oceans. The world produced 343 million tons of plastic in 2014. Only 10% of that plastic was recycled. In total we have produced 8.3 billion metric tons of plastic, which does not biodegrade for hundreds of years.

The fact is, human civilization is big enough that we have to think about the effects of our massive industry. Producing that much plastic will likely have an impact on the environment. The biggest impact may be the percentage that winds up in the oceans – about 10%. Once there is just breaks down into smaller and smaller bits. Many animals accidentally eat the plastic, which can be fatal.

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