Well, this has certainly been a tumultuous month in terms of politics. In terms of science, though it started out a bit slow, plenty of interesting stuff came out in the past couple of weeks.
- Over the long term and on a global scale, probably the biggest harm the Trump presidency could cause is in rolling back measures to tackle climate change. Fortunately the latest news is that there seems to have been a recent pause in the growth rate of atmospheric carbon dioxide. The upshot is that human industry is emitting more of the stuff than ever before, but it seems that carbon sinks have also been absorbing more of it than expected. It isn’t at all clear what is happening but the leading theory is that plants seem to be increasing their absorption of carbon dioxide in response to higher concentrations of the gas and higher temperatures.
- Also due to the recent elections, Facebook has been in the news due to its dissemination of fake news. This article covers a study in Denmark which shows that quitting Facebook seems to make people happier. Previous papers of this nature have been published before but this one involves a randomized controlled trial of more than a thousand participants recruited via Facebook itself in which half of them were randomly instructed not to use the social network for a week and the other half were instructed to continue their usual browsing habits. The effect was small but those who changed their habits did indeed seem to become happier.
- The most important science article however must be this New York Times feature arguing that growing usage of genetically modified crops seems to not have led to increased yields, nor to reduced usage of pesticides. They came to this conclusion by studying aggregate data about crop yields and pesticide usage in the United States and Canada, where genetically modified crops are common to Europe, where they are generally banned. Many commentators have since pointed out that this isn’t comparing like to like since, as you might expect, agricultural conditions within just the United States itself, vary considerably from place to place. Furthermore, decisions on what to grow come from farmers themselves and there must be good reasons why farmers, when given the choice in North America, tend to choose genetically modified crops even though those seeds are more expensive. Nonetheless, regardless of which side you take, this is an important piece of a conversation that is still ongoing.
- Moving on to better news, here’s one about the discovery that rates of dementia in the United States seem to be falling despite the fact that some of the risk factors associated with the disease, such as diabetes, are increasing. Researchers have no idea why dementia rates are falling and can only speculate that it might be linked to more education or higher cognitive demands being placed on the brain. Some commentators have instantly named this as another kind of Flynn effect.
- The most exciting news of course is the one about the EM drive. I’ve talked about it before, but to recap, it’s a reactionless space drive that requires no propellant and so seemingly violates Newton’s Third Law. A NASA team has just published a peer reviewed paper confirming that they’ve managed to detect the device generating net thrust in a vacuum. This is huge but most commentators are still skeptical and this Reddit discussion thread provides a decent summary of some of the objections. On balance, it’s still likely that this is due to experimental error but if this checks out, quite a bit of known physics will need to be redone.
- Finally, here’s a paper with a very politically incorrect conclusion. Please note that this is a non-peer reviewed paper that has been released for discussion only. It examines upward mobility of Asian Americans, showing that the group suffered plenty of discrimination, both institutional and otherwise, and yet by the 1970s or 1980s had caught up to white Americans in terms of income. The argument is that market forces subverted the discrimination as the wages of Asian Americans, despite work performance at similar levels as white Americans, were artificially depressed by the discrimination so that whichever company hired them would gain a competitive advantage. Over time, this eroded the discrimination itself. The corollary then is that black Americans did not experience similar convergence of income levels because their skills and abilities in the workplace truly aren’t, for whatever reason, as valuable, hence in their case the discrimination is exacerbated by market forces.
A little early this month due to some kinks in my posting schedule but as I have a full roster of these articles already, so why not.
- Let’s start with this discovery of a new plant species in Japan. Named Gastrodia kuroshimensis, this highly unusual plant does not use photosynthesis at all. Instead it gets all of its nutrition from the fungi that it hosts. At the same time, it produces flowers but they never bloom. Instead through a process called cleistogamy, the flowers self-fertilize within the closed buds. Perhaps the most surprising bit about this announcement is that such a strange plant can still be discovered for the first time in an area of a developed country that has already been thoroughly investigated, reminding us that new scientific findings can pop up in the most unexpected of places.
- Next is an article in a field that isn’t often featured here: chemistry! It’s about scientists discovering a new process that turns carbon dioxide into ethanol in a single step. There isn’t a lot of detail about it except that the reaction takes place in some fancifully engineered nano-structures but the claim is that the process takes little energy, low enough that it occurs at room temperature. Needless to say, if this checks out and can be scaled up, the impact would be immense as we would be turning a common pollutant into a source of energy.
- These days I often browse FiveThirtyEight for its politics coverage, but here’s a science article on the site. It talks about a statistical analysis of breast cancer data and finds that regular mammograms appears to be of little effectiveness. The study found that as mammograms became more frequent, the rate of finding small tumors increased, which is to be expected. However the incidence of larger tumors decreased by a much smaller amount, suggesting that finding tumors early does little to prevent them from growing. Most importantly the incidence of metastatic cancer was flat, meaning that early screening didn’t seem to reduce it at all. In the meantime, mortality rates from breast cancer has indeed fallen but this seems attributable to better treatment and not early screening. This result falls in line with a recent change in thinking that early screening for cancer mainly finds small tumors that would have disappeared on their own anyway and don’t need to be treated.
- Finally here’s an article from The Economist about sexual cannibalism in spiders. Most of us already know about how female black widows eats their male partners after eating, but how many of you know about the dark fishing spider, who males spontaneously die after mating and so ensure that they will be eaten? Even more strangely, the offspring of females who ate their male partners in this way were larger and more numerous even than those from females who were given a cricket of comparable size to eat rather than their male partners. This suggests that there is something especially nutritious in the bodies of the male spiders that helps the offspring and that this is the result of evolution.
I’ve long wanted to take a course about electricity since it’s one of the most mysterious parts of physics to me despite it being essential to everyday life. There doesn’t seem to be anything available on it on Coursera. I’ve been aware of the competing edX platform for a while now but hadn’t taken the time to explore it. So when I saw that it does indeed have a course on this topic, I immediately made an account.
This one is taught by Jason Hafner of Rice University and consists of five weeks worth of material. Being part one of a two part course, the coverage only stretches from the concept of charge to circuits, so don’t expect to be fiddling with complex electronics here. I consider the course to be quite difficult, especially because of the mathematics involved. There is plenty of calculus in the later weeks. Due to this, I could only follow along so far and eventually just settled on watching the lecture videos as I had no hope of completing the weekly exercises, let alone the final exam.
Continue reading Electricity and Magnetism, Part 1
Here’s my annual round-up of the Nobel Prizes awarded for the sciences just because I feel that there isn’t enough coverage of them.
Let’s start with what is probably the coolest of technologies being acknowledged. Nanotechnology is one of those fields that is always talked about but no one can quite point to an actual existing nano-machine. Every application of it so far are merely nano-scale structures which have interesting properties but aren’t machines. This year’s prize in Chemistry goes to the researchers who are starting to make this possible. Jean-Pierre Sauvage created the first simple basis for a nano-structure made up of multiple molecules by realizing that a copper ion could be used to weld molecules together. Fraser Stoddard went one step further and made molecules that could move along an axle and control that movement. Finally Ben Feringa found a way to have the molecules rotate around the axle in a chosen direction, thus creating the first simple molecular motor. No actual nano-robots have yet been made but these three scientists have effectively created the tools and parts that should one day make them possible.
Next, the prize for medicine goes to Yoshinori Ohsumi for his work on understanding the mechanism of autophagy. This is the process whereby parts of a cell is sequestered and digested by the cell itself, allowing for non-essential or damaged parts of a cell to be recycled. Beginning with yeast culture, he narrowed down the genes responsible for the mechanism and moved on to mammalian analogues of those genes. It turns out that the mechanism is far more important than previously thought and sheds light into all manner of diseases and possible avenues to treat them.
As usual the physics prize, awarded to David Thouless, Duncan Haldane and Michael Kosterlitz, is the most esoteric and difficult to explain of them all. All three scientists did work on the exotic phase transitions of matter. We’re familiar with phases like solids, liquids and gases but under extreme conditions, more exotic phases can exist. Thouless and Kosterlitz studied such transitions on flat topologies while Haldane studied them on topologies so thin and narrow that they are essentially one-dimensional strings. They showed that matter under such conditions possess unusual properties, such as the quantum Hall effect. The hope is that such research will eventually lead to new types of electronics and superconductors.
Finally the economics prize goes to Oliver Hart and Bengt Holmström for their work in contract theory. This is a broad field as it can be applied to many types of agreements between parties the most obvious being how to properly design an employment contract that provides the proper incentives to workers. Other types of contracts include insurance policies, incomplete contracts in which not all of the terms can be completely specified in advance, and financial contracts between a manager and investors.
Another good mix of articles for this month, and for the first time, one is a video instead of an article.
- Two of these articles about antibiotics and one of them is from a home-grown source. This article discusses how a Malaysian PhD student in Australia is a key contributor to the development of a nano-engineered protein molecule that is meant to rip apart bacteria. The molecule is made of peptide polymers is supposed to be able to destroy the cell walls of bacteria without harming healthy tissue, which would make it a valuable tool against antibiotic-resistant bacteria.
- This video from Harvard Medical School nicely lets you visualize exactly how quickly bacteria can evolve resistance to antibiotics. Even after they up the dosage of the antibiotics to insane levels, the bacteria still manages to find a way to thrive.
- Next up is a study that tries to estimate the health effects of the annual haze in Southeast Asia caused by fires in Indonesia. The study covers only the health effects on adults and limits itself to damage caused fine particulate matter, widely known as PM2.5. Even so its averaged result is there will be approximately a hundred thousand premature deaths due to these fires, of which around ninety percent will be in Indonesia itself. Studies like this are based on statistical analysis of models so they’re always dicey. But they’re still useful as a starting point to quantify the effects and therefore the economic damage caused by the fires, giving governments better ammunition to counter the positive economic effects of allowing these land clearing fires in the first place.
- Finally, because I can never get enough of cool findings about dog cognition, here is an article that talks about how dogs can capable of understanding both vocabulary and intonation in human speech. The researchers used an fMRI to observe the brains of dogs as they listened to human speech and they found that similar areas of their brains light up as in humans, showing that they are capable of recognizing individual words. They are also similar to humans that a separate part of their brains process the intonation of the speech, allowing them to gain an understanding that encompasses both the meaning of the spoken words and the intonation with which they were spoken.
A good variety of stuff for this month:
- I would be remiss if I didn’t include the biggest scientific news of the month but honestly, there’s so little information here that it’s barely worth getting excited about. This refers to the announcement that astronomers have found a planet within the habitable zone of Proxima Centauri, which being 4.2 light years away, is the closest star to our own system. Here’s a decent article about it. The most important thing to remember is that the planet being in the habitable zone doesn’t actually mean that it’s habitable. It just means that it’s right distance away from its star such that water can exist there in its liquid state. In particular, because Proxima Centauri is such a cool star, the newly discovered star orbits really close to it, which means that it must be bathing in radiation and any potential life on the planet must be subject to a host of other similarly hostile conditions.
- This CBC article talks about how the common wisdom that turtles are the longest lived animals may be wrong. A recent study found that the Greenland shark may have a lifespan of 400 years. This determination was difficult to make as obviously this far exceeds the duration of any scientific study and the scientists must use estimates based on dating how old the animals are. In this case, they used radiocarbon dating techniques on the lenses of the sharks’ eyes and found that their average ages are well over 200 years. It is also thought that they only reach sexual maturity between the ages of 130 and 170.
- Next, there’s this report about Japan about how a woman was successfully diagnosed that she is suffering from a rare form of leukemia using IBM’s famous Watson system. The patient was initially diagnosed by doctors of having a different form of the disease but the doctors were stumped when she failed to respond as expected to the treatment. The AI however was able to sift through much more data than human doctors can handle to point the doctors in the correct direction. This comes on the heels of many other recent announcements of AI being used in unconventional ways, including recommending sentences for criminal uses to judges and helping teachers to create customized learning plans for individual students.
- Finally The Economist covers an intriguing discovery that men may be better than women at making up after a conflict. The study focuses on athletes. Competitors in many sports are expected to make peaceful physical contact after an event, shaking hands for example or embracing. The scientists found that such making up activities seemed more genuine in men than in women. The men would grasp hands for longer, even pat shoulders or touch arms after the initial contact. Women on the other hand seemed to do the minimum that was required by convention and no more. The speculation is that men may be better conditioned than women to regard conflicts as being nothing personal and not to hold grudges after a winner has been determined.
Not many articles this month and most of them are about medicine. I didn’t realize that until I sat down to write this post.
- Starting with the non-medical science article first, this is piece about how each distinct community of sperm whales may have their own unique culture. The researchers studied groups of the whales in the Carribean, using microphones to record the sounds they make and track their interactions. They found that each clan has their own dialect that family members explicitly teach to new calves but there are also codas, or words, that they share in common with sperm whales of other clans.
- This next article talks about the medical mystery of how incidences of major diseases in many wealthy countries seem to be dramatically dropping for no discernible reason. These include colon cancer, heart disease, dementia, hip fractures and so forth, each seemingly unconnected with another. One obvious cause is that better technology and practices should result in better diagnosis and treatment but the researchers found that the rates are still down after controlling for these factors. No one knows what other explanation there could be but I guess people are just in general living more healthily now in rich countries, contrary to the popular impression that humans are becoming ever more unhealthy.
- Readers of this blog should probably already know that mitochondrial DNA, which comes only from the mother, is different from nuclear DNA, which comes from both parents. Nevertheless it is thought that they have co-evolved together through generations and therefore DNA from the same lineage should work better together. Current cloning technology however mixes mitochondrial DNA with nuclear DNA of two different and presumably distantly related donors. The surprise is, as this article explains, that the resulting organisms seem to live longer rather than shorter as you might expect. The current guess is that some small amount of adversity, in this case caused by the two types of DNA being not completely compatible, is sometimes beneficial to the organism, and how true this is remains yet unknown.
- Usually when we see advertisements or click-bait headlines like oil companies don’t want you to know this energy-saving secret it’s either a scam or crazy conspiracy bullshit. So this bit of news about how mainstream dentists are hindering the widespread adoption of a treatment for cavities that doesn’t require any drilling looks suspect. Except that this comes from a reputable source and the treatment, an antimicrobial fluid called silver diamine fluoride, has already been cleared as being safe by the FDA in the US and has been used for decades in Japan. The fluid can’t save teeth that has already been too damaged but it can prevent cavities from becoming worse and prevent new ones from occurring. The only downside is that it may blacken portions of teeth that have already been damaged by cavities. The upside however is that its cheap, quick to apply and requires no surgery.