I’m starting out this week by admitting one of my own biases … against bias. And how that can lead to bias. if that sounds confusing, it’s because it’s a difficult issue. Here’s the article that spawned it:
Hominins arrived in China over two million years ago.
A paper by a team from the Chinese Academy of Sciences reports the discovery of stone tools from a site called Shangchen in eastern China, dating back 2.1 million years. That’s an extraordinary number, as the oldest previously known human-line remains outside of Africa are a couple of teeth that date to around 1.8 million years. Pushing back the exodus of human relatives from Africa by 300,000 years doesn’t “upend” or “rewrite” human evolution by any means—no matter how many media reports this week implied that it does. However, it could call for a reordering of the sequence of events when it comes to the dispersal of various human ancestors, and touch on again the idea that some groups of humans have ancestors who developed parallel to modern humans outside of Africa. The findings in this case are a set of stone tools — flaked flint, flint cores, and simple scrapers — that show evidence of being “worked.” There are also animal bones in the location that may indicate butchering activity. There are no human bones.
And here’s my issue with this. I’m very reluctant to believe this article because of two things. Let’s call them “rocks” and “geography.”
Rocks: In theory, worked stone tools should be a very handy indicator of human presence. Departing a little bit (but only a little bit) from the topic, the reason there are so many fossils of trilobites in ancient rocks isn’t just because trilobites were so abundant (though they were), but because they, like arthropods today, molted their hard outer shell multiple times as they grew. So a single trilobite could potentially leave behind many fossils. Humans, inconveniently for paleoanthropologists, don’t do that. We have just one skeleton to leave behind. So when human populations are small, there may not be many bones to go around. Which is why several human occupation sites in Asia and elsewhere are marked by only a bone here, a tooth there. On the other hand, one human could make a lot of stone tools. So tools should be easier to find than bones. Stone tools are the cast off trilobite shells of human fossils! Only … it’s not that easy. Because while it’s easy to identify an exquisitely made fluted arrowhead, or grooved ax, or a distinct Clovis spearpoint, that’s not what we are talking about here. These are rocks whose “working” amounts to not much more than being smacked around a bit. It is very easy to mistake a naturally broken rock for something man, or near-man, made. That’s especially true when it’s being examined by folks who really, really want to find something. And it’s why the history of anthropology and archaeology is replete with “artifacts” that, on close examination … aren’t. So the fact that Shangchen has rocks, but no human bones, no definite proof of deliberate fires, and no clear evidence of butchering … makes me a doubter.
Geography: And now we come to the one where my own bias-bias gets in the way. Whenever anthropologists start suggesting something that might, even with a few twists and turns, lead to the idea that some groups of humans evolved, or at least partially evolved, in Asia, it fires off my auto-dander-up response. That’s because, at least as far back as Darwin suggesting that most apes today are found in Africa and it was very likely that humans also evolved in Africa, people have been suggesting that some groups didn’t originate in that “dark continent.” Instead, they’ve searched for ways to suggest that some groups evolved in Asia. Perhaps groups that eventually became part of a proto-Indian-Iranian migrant group also known as Aryans. In short, I look at every article indicating greater early human presence in Asia as a possible foot-in-the-door to an argument that some groups of humans evolved separately from others. Because “separately from” is a short hop to “better than.”
And that’s where my own prejudice gets tangled in this thing. Because … maybe these guys are right. Maybe early hominins were prowling around China, hacking up the local pig population, hundreds of thousands of years earlier than expected. Maybe my own prejudices against prejudice is making me prejudice. Honestly, I hate to think that my own feelings about a matter of science are being swayed because there’s an outcome I want to see. After all, isn’t that exactly what I’m accusing the always-hunting-Aryan group of doing?
However, I promise that I will eagerly dive into the possible consequences of this dating. But first … they’re going to need better rocks. Or a single tooth. That’s not a lot to ask.
There are a ton of interesting pieces this week. So excuse me for skating over them very quickly. I’m going to just dash through with little more than titles and a very brief summary, and I’m still not going to touch on more than a fraction of what showed up this week.
Biodiversity
Sea birds, rats, and coral.
When we think about human impact on ecosystems, one of the factors most overlooked is how humans have redistributed creatures around the globe. That’s true of both pests we spread on purpose—like goats and pigs—and those we spread unintentionally, but inevitably, like rats. Rats have a huge impact on island ecology, especially when introduced to small islands where there are often no predators and no other mammals. They make short work of ground-nesting birds used to having their eggs, and chicks, safe on the sand. But a group led by James Cook University in Australia shows that the impact of rats doesn’t just affect what goes on above the waves of these tiny islands and atolls. It can even cause devastation of coral reefs by altering the flow of nutrients.
We found that seabird densities and nitrogen deposition rates are 760 and 251 times higher, respectively, on islands where humans have not introduced rats. Consequently, rat-free islands had substantially higher nitrogen stable isotope values in soils and shrubs, reflecting pelagic nutrient sources. These higher values of N were also apparent in macroalgae, filter-feeding sponges, turf algae and fish on adjacent coral reefs. Herbivorous damselfish on reefs adjacent to the rat-free islands grew faster, and fish communities had higher biomass across trophic feeding groups, with 48% greater overall biomass.
Add rats … and you get sick coral reefs. That is not an obvious change. But it’s a very good example of interconnections.
Genetics
High quality genome maps detail differences among our closest relatives.
The idea that humans are very closely related to other members of the Great Apes gets tossed around in terms of percentages — 4 percent different from this, 6 percent different from that — but new genome maps provide a finely detailed model of just what separates us from a Gibbon, and an Orangutan from a Chimpanzee. And it’s interesting that the original map of Apes … used humans for the template.
Because of these difficulties, the first great-ape genome projects used the human genome as a scaffold to help assemble genomic regions that are structurally similar to those of humans — that is, in which corresponding stretches of DNA lie in the same order and are present in a similar number of copies. This strategy enabled better assembly in such regions. But in regions where genome structure has evolved very differently in humans and other great apes, the great-ape draft assemblies tended to be more fragmented, and the resulting variation in assembly quality effectively constituted a bias towards the human genome. These assemblies provided many evolutionary insights, but there has nonetheless been a deficit in our understanding of the genomic elements that make humans unique.
In Jurassic Park terms, we were that frog that the scientists improbably used to fill in all the gaps on the dinosaurs. And no, I still don’t know why a frog.
Potato. Pompeo. No, wait … it is a potato.
Why was Kim Jong Un so ready to pass up talking to Secretary of State Mike Pompeo to visit a potato farm? Maybe he knew the secret: Potatoes have big genes. Or at least, that’s been the common theory. But a letter this week from researchers at Oxford says otherwise.
In a recent issue of PNAS, Hardigan et al. state that the genetic diversity of the potato is much greater than that of other major crops, based on 68.9 million SNPs identified from the resequencing of 67 accessions of wild and cultivated potatoes. We questioned this conclusion based on our own original analysis of wild and cultivated potato species and estimates of genomic SNPs in other major crops by next-generation resequencing with a few to 15 million SNPs. Examples include soybean, pigeon pea, cotton, tomato, and potato.
So show up at your meetings, Kim! And now I need a British person to explain to me what a “pigeon pea” is.
Sociology
Do poor white people in the United States have declining mental health.
The idea that poor people of any color are suffering increased levels of depression is certainly upsetting. It’s also impossible to read about without trying to draw some connection to Trump voters. Only … it’s hard to tell which direction the arrow between “declining mental health” and “voted for Trump” should be directed. In any case, Andrew Cherlin from Johns Hopkins University, looked again at the idea of non-Hispanic whites in decline.
Much attention has been paid of late to drug abuse and mortality among less-educated whites. This group, often referred to as the “white working class,” is typically defined as non-Hispanic whites who do not have Bachelor of Arts or Bachelor of Science college degrees. Mortality rates have risen for members of the white working class in midlife, mainly due to increases in drug overdoses, suicides, and alcohol-related liver mortality. In contrast, mortality rates for African Americans and Hispanics have continued to decline. These findings have contributed to a popular narrative of rising malaise among the white working class, leading to a surge in “deaths of despair” and to support for Donald Trump in the 2016 Presidential election.
And the answer seems to be … yes, working class white people, as defined by the limits of the studies involved, appear to have declining mental health as measured on some indexes.
In black neighborhoods where police are often ineffective … people call the police more.
A study of African American neighborhoods where crime rates were above average and police actions were judged ineffective generates a result that may not seem immediately obvious — people are more likely to call 911 and report crimes. According to researchers from Northwestern and UC Davis, the rate of 911 calls goes up in neighborhoods that are experiencing higher rates of negative interaction with authorities — such as high levels of incarceration and foreclosures.
And why would that be? Pretty much what you might expect. Residents in racially-isolated, low income communities are more likely to have a negative encounter with authority. Also also more like to have very limited options.
The implication is that in the absence of alternatives, and despite past and continuing perceived police ineffectiveness, residents in racially isolated and disadvantaged neighborhoods will continue to call 911, seeking crime prevention and protection by police.
While it may sometimes seem like the goal is to make police so hostile to calls from black residents that they will just stop calling, we’re not quite there. Yet. But there’s more to it. Residents of racially isolated black neighborhoods call 911 more often than residents of more diverse neighborhoods, for the same levels of crime.
Cynicism about lawlessness and police crime prevention and protection efforts is often high in predominately African-American neighborhoods, but residents persist in calling 911 and requesting police assistance.
Why Einstein is Einstein. And Fermi is Fermi. But Marie Curie is always Marie Curie.
Across eight studies combining archival and experimental methods, we report evidence for a gender bias in how people speak about professionals. Men and women were, on average across studies, more than twice as likely to describe a male (vs. female) professional by surname in domains, such as science, literature, and politics. We find that this simple difference in reference affects judgments of eminence, with participants judging those professionals described by surname as more eminent and 14% more deserving of a career award. This gender bias may contribute to the gender gap in perceived eminence as well as in actual recognition and may partially explain the persistent state of women’s underrepresentation in high-status fields, including science, technology, engineering, and math.
The “single name” market is seen as a sign of importance in many areas of entertainment and politics. The same is true in science. The fact that people feel comfortable tossing off a “Heisenberg,” but rarely deliver a “Fossey” without “Dian” suggests that sexual bias exists in handing out that mono-moniker, even among non-scientists when considering scientific achievements.
Energy
Does a falling percentage of power production by nuclear mean the US is upping its carbon footprint.
A group led by researchers from Carnegie Mellon University questions the decline of electrical production by nuclear in the US and how it will impact the environment.
Nuclear power holds the potential to make a significant contribution to decarbonizing the US energy system. Whether it could do so in its current form is a critical question: Existing large light water reactors in the United States are under economic pressure from low natural gas prices, and some have already closed. Moreover, because of their great cost and complexity, it appears most unlikely that any new large plants will be built over the next several decades. While advanced reactor designs are sometimes held up as a potential solution to nuclear power’s challenges, our assessment of the advanced fission enterprise suggests that no US design will be commercialized before midcentury. That leaves factory-manufactured, light water small modular reactors (SMRs) as the only option that might be deployed at significant scale in the climate-critical period of the next several decades.
The majority of this work concerns developing a market for, and managing the deployment of, these SMR plants. These small nuclear plants aren’t a new idea. The industry has been pushing for them for decades, and a number of “intrinsically safe” designs have been put forward. But they are simply not there. Not only are they unlikely to appear overnight, differentiating these plants in the public eye from their larger kin, or securing broad political support for their deployment, is a task that seems to have barely begun.
Barring some serious change in the energy marketplace — and serious changes do happen, just ask the coal industry — it seems unlikely that a new commercial nuclear power plant will go online in the United States at any time in the next two decades. That could change if someone important, say like Khloe Kardashian, got behind the idea. But … I’d be willing to put up at least $20 that we’re more likely to see a nuclear fusion plant in the US before we see another nuclear fission plant.
Medicine
A pathway to oral insulin.
Insulin injections are painful and annoying, inconvenient and even life threatening. But when the body isn’t making enough insulin, an injection or pump is generally the only alternative. Oral insulin sounds simple enough, only insulin is broken down in the digestive tract, and doesn’t enter the bloodstream where it is needed intact. But may groups have looked at ways to address that issue. This team from US Santa Barbara has an intriguing solution (and you can take that literally).
We have developed a safe and highly effective ionic liquid-based oral insulin formulation that significantly enhanced oral insulin absorption by efficiently circumventing the gastrointestinal barriers. Besides, the formulation demonstrated good stability at room temperature and under refrigeration. Evidence from cell and animal studies supports a promising prospect of development of the formulation into a clinical product.
The idea of a take-by-mouth insulin that can packed along for days on a hike or a maybe even sold in a can at a store would be extremely freeing for a large number of diabetics. And no one would miss those damn needles.
The formulation exhibited high biocompatibility and was stable for 2 months at room temperature and for at least 4 months under refrigeration. Taken together, the results indicate that CAGE is a promising oral delivery vehicle and should be further explored for oral delivery of insulin and other biologics that are currently marketed as injectables.
Note that the testing these folks are doing is still at the “in rats” level. One the one hand, that’s a groan-generator, because it puts this at a very early stage. On the other hand, this sort of trial of a new delivery mechanism is likely to move much more quickly than one introducing a new agent. So … keep watch. This won’t be on the shelves tomorrow, but it could be in the news very soon.
How does sickle cell anemia protect against malaria?
It’s one of those examples that appears in a thousand textbooks — humans who have the genes that cause sickle cell anemia suffer all the ill effects of that disease. And yet, they may actually be at a genetic advantage when it comes to passing along those genes in some regions, because those with sickle cell are less likely to develop severe cases of malaria. So … why? Some Harvard researchers believe they’ve nailed the mechanism behind this.
We demonstrate that polymerization of sickle hemoglobin (HbS) is responsible for this growth arrest of intraerythrocytic P. falciparum parasites, with normal hemoglobin digestion and growth restored in the presence of carbon monoxide, a gaseous antisickling agent. Modeling of growth inhibition and sequestration revealed that HbS polymerization-induced growth inhibition following cytoadherence is the critical driver of the reduced parasite densities observed in malaria infections of individuals with AS. We conclude that the protective effect of AS derives largely from effective sequestration of infected RBCs into the hypoxic microcirculation.
Yeah, that’s clear as … blood. To clear it up a bit, Plasmodium falciparum is the primary organism behind malaria in humans. It seems that because the hemoglobin of cells with the sickle cell varient carry a lower level of oxygen, it causes p. falciparum to essentially stall out in the middle of replication.
Image
This week’s image is from Andy Brunning and Compound Interest. As usual, visit his site to see a larger, easier to read version and check out his library of infographics.