Archive for the 'General Science' Category

Oct 05 2018

Neanderthal Healthcare

Published by under General Science

Neanderthals were our close cousins. They are the closest species to modern humans that we know of. There is also the Denisovans, which are currently classified as a subspecies of Homo sapiens, but may eventually be classified as their own species.

Neanderthals lived from 400,000 to 40,000 years ago. They spread out of Africa, and throughout Europe and Asia. When modern humans arrived later, there was some clear interbreeding going on – Europeans and Asians have about 2% Neanderthal DNA. In fact a recent study suggests that modern humans specifically retained Neanderthal genes that conveyed improved resistance to European viruses.

The first fossil specimen of Neanderthal was discovered in 1829, although this was not recognized until later. The first recognized specimen was collected in 1856 in the Neander valley in Germany. This was the first early hominid specimen found. Perhaps because of the time it was discovered, our image of Neanderthal is still colored by the notions of the day. “Primitive” was synonymous with brutish and animalistic.

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Sep 25 2018

Fighting Back Against GMO Pseudoscience

Published by under General Science

The organic food lobby has been successfully demonizing safe and effective biotechnology for the last two decades. Part of their strategy is to create a false dichotomy between GMO (genetically modified organisms) and non-GMO. In reality there is a continuum of methods used to alter the genetics of crops that we have been using for centuries. There are real differences among these various techniques, but they do not divide cleanly into two categories (more on this below).

The Non-GMO Project is part of this strategy. You have probably seen the labels, with the appealing butterfly reassuring consumers about the wholesomeness of products. Even when there are no GMO options for a food type, you can get the label. This scam makes money for the Non-GMO Project and is good for marketing. The goal is to eradicate any technology this non-expert and private group decides is GMO.

Now, the Information Technology and Innovation Foundation is hitting back. They are a non-profit science think tank whose purpose is to provide non-partisan science information to inform policy. They have submitted a petition to the FDA:

The Non-GMO Project food label deliberately deceives and misleads consumers in violation of the Federal Food, Drug and Cosmetic Act. ITIF petitions FDA to prohibit such labels. The “Non-GMO” Project butterfly logo and label on consumer foods and goods misleads and deceives consumers through false and misleading claims about foods, food ingredients and their characteristics related to health and safety, thus constituting misbranding under the law. ITIF therefore requests, in a Citizen’s Petition submitted to the Commissioner of Food and Drugs, that FDA issue a regulation to prohibit the use of the term “Non-GMO” on consumer foods and goods, and to require distributors of foods and goods to revise their labeling to omit any “Non-GMO” term, symbol, or claims.

This is essentially correct – one could argue that the purpose of the Non-GMO label is to confuse and misinform consumers, in order to extract more money out of them for equivalent or even inferior products.

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Sep 13 2018

Hurricane Pseudoscience

Hurricane Florence is about to hit the Carolinas, extending as far south as Georgia and north as Virginia. The storm peaked at a Category 4, but now as it approaches land has been downgraded to a Category 2 hurricane. Hurricanes generally gain power over the ocean, from the energy of water evaporating off the surface, and then lose power when they hit land.

But this weakening does not mean that the storm is not dangerous. The category refers only to wind speeds, but there are other factors to consider. First, this is a very large storm. Also, it is slowing down, so may stall over the Carolinas. This means it can just sit there, dumping large amounts of water. The two dangers are storm surges and flooding. A storm surge is the rise in sea level above the normal high tide, caused by the wind. This can rapidly flood coastlines.

Flooding occurs when rivers overflow their banks and there is simply too much water too fast to be absorbed into the ground or flow back to the ocean. Flooding and storm surges actually cause most of the damage and deaths during large storms, not the wind itself.

Dramatic storms like Florence always seem to prompt fresh discussion about the effects of global warming and what we should be doing about it.

Here is a good summary by the Geophysical Fluid Dynamics Laboratory of the effects of AGW on tropical storms. Warming does not increase the number of storms, but it does increase the average intensity of storms and the amount of water they drop. Therefore, statistically we should be, and are, seeing more intense storms and more flooding.

Of course you cannot blame any single storm on AGW – it is a statistical effect.

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Aug 23 2018

The Superconductivity Hubbub

A recent paper, published to arXiv, claims to have a method for making a superconducting material at ambient temperatures and pressures. The authors, Dev Kumar Thapa, Anshu Pandey, are from the Indian Institute of Science, and have garnered a lot of attention for their paper. However, recently there was published another paper on arXiv by Brian Skinner from MIT. Skinner noticed a suspicious pattern of repeating noise in two sets of data from the Thapa-Pandey paper. This could be a signature of fabricated data.

Scientific American has a good summary of the whole story, but that’s the quickie version. Skinner did not make any accusations, just published his analysis with a question to the original authors to explain the repeating pattern. Thapa and Pandey have responded only to say their results are being replicated. The rest of the physics community is not satisfied with this response, and are calling for them to send their material to outside labs for completely independent testing.

Another wrinkle to the story is that Pratap Raychaudhuri, a physicist at the Tata Institute of Fundamental Research in India, floated a hypothesis that perhaps the noise is not noise, but a signal resulting from “the natural rotation of particles within a magnetic field.” If that’s the case, then the pattern should replicate. So we are still left with the need to independently replicate the experiments.

The stakes here are high because so-called room temperature superconductivity is one of the holy grails of material science. Superconductivity means that electricity can flow through the medium without resistance, and therefore with no loss of power. A room temperature superconductor could therefore transform electronics, the power grid, and anything using super powerful magnets (like MagLev trains and MRI scans).

The current dominant theory as to how superconductivity works in certain materials two electron can come together to form what’s called a Cooper pair. This pair of electrons can then travel long distances in the material without resistance. However, Cooper pains can only exist at very low temperatures. So the quest has been to find materials that will allow Cooper pairs to exist at higher and higher temperatures.

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Aug 09 2018

The Climate Tipping Point

Published by under General Science

It’s now pretty clear that as we increase global CO2 levels in the atmosphere, mainly by burning stuff, global average temperatures have been increasing as well. This is predicted based upon the greenhouse effect of CO2 and other gases like methane, amplified by reactive gases like water vapor. The amount of warming that results from a given CO2 increase is called climate sensitivity (specifically the rise in average global temperature averaged over 20 years resulting from a doubling of atmospheric CO2), and there is some debate about exactly what the climate sensitivity is.

Without any feedback effects, from just the primary greenhouse effect of CO2 itself, climate sensitivity is about 1 degree C. However, there are feedback effects, meaning that rising temperatures affect the climate in such a way that more warming results. For example, if the polar icecaps reduce in size, they reflect less light back into space, which results in more warming. Current estimates of climate sensitivity are between 2 and 4.5 degrees C.

However, a new paper published in PNAS argues that climate sensitivity is not the only issue when it comes to predicting future climate change due to increased CO2. Those feedback loops do not only affect climate sensitivity – they also affect climate homeostasis. In other words, at any given amount of CO2 in the atmosphere, taking into consideration all the feedbacks in the climate, an equilibrium will be achieved. There are climate cycles around that equilibrium, but that equilibrium determines long term global average temperatures.

So – what we really need to do is determine where the new equilibrium will settle for any given amount of CO2. This requires predicting not only the effect of feedback loops on the climate, but their effect on each other. The authors argue that several feedback mechanisms can act like a domino effect – on feedback will increase temperatures enough to set off another feedback which increases temperature enough to set off yet another feedback. This whole chain has to work itself out before a new equilibrium is reached.

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Aug 07 2018

How Much Arable Land Is There?

Published by under General Science

This question comes up frequently in discussions of farming practices – how much arable land is there on the Earth, and how much are we currently using? It is a deceptively difficult question to answer. It’s an important question, because as the population grows, we need to grow more food. We can do this my increasing the amount of food each acre of land can produce, by farming more acres of land, or by producing food without land. But if we expand farming acres, where would those more acres come from?

Let’s start with the easy question – right now we are using 11% of all the land on Earth for farming (1.5 billion ha out of a total of 13.4 billion). What percentage of the remaining 89% could be used for farming? The answer is – that depends on your definition of arable land. We can take the upper limit of the estimate of remaining arable land, and then explain why use of that land is problematic.

First, “arable” is a continuum, not a dichotomy. Some land can only be used for a very limited number of potential crops. Other land is highly suitable for many different crops. We won’t count land that is not suitable for farming, even though theoretically it could be used with extreme measures. You can grow corn in the desert, if you import all the water.

If we count all potentially arable land, it is estimated that we are currently using 36% of that land for farming. That means that 64%, or 2.7 billion ha, remain. At first this may seem encouraging, that we have lots of farmable land left. But that figure is very deceptive. Let’s dive into that 64%. The fact is we have already “picked the low hanging fruit.” We have used the best farming land for farming. What remains is largely on the low end of the continuum of suitability. If, for example, land can be used only for olive groves, that is considered arable by the above calculation.

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Jul 09 2018

USDA Tries to Implement Terrible GMO Labeling Law

Published by under General Science

The USDA just ended their public comment period on their proposed execution of the terrible Federal GMO labeling law passed in 2016. The public comments reflect the mess this law is, and why it is a bad idea.

The law simply states that the USDA will develop rules for mandatory labeling of bioengineered food. Here is the relevant definition in the law:

‘‘In this subtitle:
‘‘(1) BIOENGINEERING.—The term ‘bioengineering’, and any similar term, as determined by the Secretary, with respect to a food, refers to a food—
‘‘(A) that contains genetic material that has been modified through in vitro recombinant deoxyribonucleic acid (DNA) techniques; and
‘‘(B) for which the modification could not otherwise be obtained through conventional breeding or found in nature.

The first criterion – in vitro recombinant DNA techniques – is at least fairly specific. However, it does not distinguish cisgenic (from a closely related species) from transgenic (from a distant species). This does not technically include gene silencing, because no new material is being sliced in. Therefore by this definition “GMO” cultivars produced through gene silencing do not need to be labeled ad BE (bioengineered).

Perhaps because this first criterion is not specific to transgenic alterations, the second criterion was added – not obtained through breeding or found in nature. The “found in nature”, however, is very problematic. This is because transgenic gene transfer does occur in nature, – so called horizontal gene transfer. In fact, recently a sweet potato variety was found to have a naturally-occurring transgene from a soil bacteria.

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Jul 06 2018

Land Use and Climate Change

Published by under General Science

There is a strong scientific consensus that the primary driver of climate change is the release of previously sequestered carbon locked away in fossil fuels into the environment. But a new study reminds us that there is another contributor that must be accounted for in climate models – changes in land use.

The core claim of climate change is actually quite simple, and has not been successfully refuted by climate change deniers. So-called “greenhouse gases” in the atmosphere warm the planet because they reflect more infrared radiation back down to the surface, so that less of it escapes the Earth. Without this effect the Earth would be a snowball.

It is irrefutable at this point that adding more greenhouse gases to the atmosphere will increase this effect, resulting in more warming. The only real question is – how much warming? This is where things become ridiculously complex. Climate scientists use models to predict what will happen as more CO2 is released into the atmosphere, but it is very difficult to model a complex system. This is why there are large error bars on projections of future warming.

As a quick aside, carbon dioxide (CO2) is not the only greenhouse gas, but it is the major one. Methane is a more potent greenhouse gas (GHG) than CO2, but it does not last as long in the atmosphere. Within the first 20 years after its release, methane is 84 times as potent a GHG than CO2, but only 34 times if you consider its effects over 100 years. Much less methane is released into the atmosphere than CO2, but it is not negligible and needs to be considered in climate models.

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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

Published by under General Science

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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