Author: John Timmer

(credit: US Health and Human Services)

Physics researchers have a long history of sharing work they're preparing for publication in order to solicit suggestions and comments from their peers. Like so many things, this behavior migrated to the Internet: Cornell University's arXiv server hosts over 1.1 million documents, many of which later appeared in formal peer-reviewed literature.

The physics and astronomy communities see arXiv as beneficial, and biologists put together their own database called The BioRxiv. Now it appears that chemists are going to get their own equivalent. The American Chemical Society is asking for input from the research and publishing communities about what they'd like to see in a ChemRxiv.

The structure of the service will probably be the same as it is for other fields: manuscripts can be posted and shared prior to submission for peer review. The American Chemical Society's stated goal is to have information get circulated faster, which should accelerate the pace of scientific discovery. For individual researchers, the benefits may include having any errors or misinterpretations caught and fixed before hitting the peer review process.

(credit: Paul Scherrer Institute)

Although tiny, a proton takes up a finite amount of space, enough to fit three quarks, a host of virtual particles, and their associated gluons. The size of a proton's radius is determined by these particles and their interactions, and so is fundamentally tied in to theories like the Standard Model and quantum chromodynamics.

We can measure the radius because the proton's charge is spread across it, which influences the orbit of any electrons that might be circling it. Measurements with electrons produce a value that's easily in agreement with existing theories. But a few years back, researchers put a heavier version of the electron, called a muon, in orbit around a proton. This formed an exotic, heavier version of the hydrogen atom. And here, measuring the proton's radius produced an entirely different value—something that shouldn't have happened.

This “proton radius puzzle” suggests there may be something fundamentally wrong with our physics models. And the researchers who discovered it have now moved on to put a muon in orbit around deuterium, a heavier isotope of hydrogen. They confirm that the problem still exists, and there's no way of solving it with existing theories.

(credit: Avilés lab, UBC)

Spiders are notoriously antisocial, with a number of species known for making a meal out of recent mates. But there are some notable exceptions to that rule, called the social spiders. These can form groups of thousands of spiders, which cooperate to capture prey and build nests that can grow up to six meters long. Their group construction projects allow them to hunt prey that is much larger than any of them could capture individually.

For one species, Anelosimus eximius, however, these big nests appear to come with big risks. Some population surveys indicate that over 20 percent of nests end up going extinct each generation. And, since only mature females that have already mated can successfully start up new nests, this means that most of the spiders in the nest end up dying.

Now, researchers from the University of British Columbia have proposed an explanation for the population busts. It seems that the spiders are a bit too good at sharing, so that even weak and immature colony members are generally able to get something to eat. And, if food ever gets a bit short in the nest, that means that none of the spiders may get enough food to survive.

Reconstruction of a collision inside the CMS detector. (credit: Brookhaven National Lab)

Toward the end of last year, the people behind the Large Hadron Collider announced that they might have found signs of a new particle. Their evidence came from an analysis of the first high-energy data obtained after the LHC's two general-purpose detectors underwent an extensive upgrade. While the possible new particle didn't produce a signal that reached statistical significance, it did show up in both detectors, raising the hope that the LHC was finally on to some new physics.

This week, those hopes have officially been dashed. Physicists used a conference to release their analysis of the flood of data that came out of this year's run. According to their data, the area of the apparent signal is filled by nothing but statistical noise.

The search for new particles in data from the LHC starts with a calculation of the sorts of things we should expect to see at a given energy. The Standard Model, which describes particles and forces, can be used to make predictions of the frequency at which specific particles will pop out of collisions, as well as what those particles will decay into. So, for example, the Standard Model might indicate that two electrons should appear in five percent of the collisions that occur at a specific energy. Looking for new particles involves looking for deviations from those predictions.

(credit: California Stem Cell Agency)

On Thursday, the National Institutes of Health announced that it was revising the rules that govern its funding of stem cell research. The rules focus on cases where human stem cells are introduced into embryonic animals, creating an embryo that's a mixture of human and animal tissues. While the rules would lift a blanket moratorium on funding for this research, they'd also tighten the regulations that were in place prior to the moratorium.

An animal that's a mixture of two different organisms is called a chimaera. While they're named after mythological beasts, creating them is rather run-of-the-mill in modern research, where chimaeras between different mouse strains are an essential part of knocking out genes to study the effects. Human-mouse chimaeras are also quite common, as we inject human tumor cells into mice to study cancer and replace the mouse immune system with a human one in order to study diseases like AIDS.

Some stem cell research would be similar in nature. For example, if you wanted to determine if it is safe and effective to use stem cells to repair cardiac injury in humans, a reasonable first step would be to see what happens when you inject human stem cells into an adult mouse that has a damaged heart.

An artists' rendering of an eclipsed Io, lit by its own volcanic activity. (credit: Image Courtesy of Southwest Research Institute)

Jupiter's innermost large moon, Io, is one of the most dramatic bodies in the Solar System. It's the most volcanically active thing we've ever seen, and its surface is spotted with pools of liquid sulfur and punctuated by some of the largest mountains in the Solar System. The Jovian environment bombards it with intense radiation, and the giant planet's magnetic field sweeps away material from Io and sends it on to other moons.

Now, researchers have found evidence that the moon's thin atmosphere has its own dramatic behavior, condensing and collapsing to the surface whenever deprived of sunlight. In making this discovery, we've probably also learned where the atmosphere originated.

The atmosphere of Io doesn't make it the sort of place you'd want to draw a deep breath. For one, it's incredibly thin, so nothing like a deep breath would even be possible. But the kicker is that its major component is sulfur dioxide, which would react with the water in your lungs to form a strong acid.

A lot of things that try to pass themselves off as science, like homeopathy, clearly aren't scientific. But it might surprise you to know that there's no simple checklist or flow chart that lets you separate the scientific from the nice-try-but-not-quites. It's not for lack of trying; for decades, philosophers worked to figure out how a decidedly human activity could produce such reliable information, but all the big-name thinkers in the field have come up short.

Understanding why they failed is the subject of multiple graduate-level seminar classes. But if you're just interested in a brief overview, Tim Lewens can help you out.

Dr. Lewens is a philosopher of science at Cambridge University (and a Ford driver, as we discover) who's written a book called The Meaning of Science. It's meant for a general audience, yet it tackles hairy issues in the philosophy of science and throws in ruminations on the nature of humanity for free. The Meaning of Science is an odd mix that doesn't quite hang together as a coherent whole, but it's not a bad read for anyone interested in a quick-and-painless introduction to the mystery of why science works.

(credit: M. Garlick/University of Warwick/ESO)

When observing AR Scorpii, researchers noticed that its brightness varied over a 3.5 hour period. So they labelled it a periodic variable and paid it no further attention. Now, however, a large international team of astronomers has gone back and taken a more careful look at the star. The astronomers found that AR Scorpii is much more variable than first thought, with 400 percent changes in brightness occurring within only 30 seconds. The reason for this? AR Scorpii is actually two stars, and one of them is launching relativistic electrons at the other.

The paper describing these results was published this week in Nature.

The researchers were drawn to AR Scorpii because of seven years of archival images that revealed a lot of additional variability layered on top of its well-described 3.5 hour period. Rather than peaking at a similar level each time, the output could vary by as much as a factor of four.

(credit: Delaware.gov)

Soft, juicy, delicious tomatoes were a feature of my childhood and are still available from the plants I grow each summer. However, they've largely vanished from stores. The ripe fruits don't hold up well to shipping, so producers have focused on growing variants where mutations have partially blocked the ripening process. These tomatoes stay firm longer, but it comes at the cost of texture and flavor—as well as a decline in their nutritional value.

Now, researchers seem to have identified an enzyme that specifically helps soften the tomato during the ripening process. By knocking its activity down, they've interfered with softening while leaving other aspects of the ripening process intact. The result is a ripe fruit that can sit at room temperature for two weeks and still remain firm.

In some ways, the surprise of these results isn't that they happened; it's that they took so long. A high-quality tomato genome sequence was first published in 2012, and it allowed researchers to identify more than 50 genes that were likely to encode proteins that could modify the plant cell wall. Four of these genes appeared to be active at high levels in the ripening fruit, and so these genes were targeted through genetic engineering.

Features of how DNA, RNA, and proteins are built and metabolized are common to every living thing we've looked at, suggesting they were inherited through common descent. While life may have arisen more than once, it appears that only one lineage has survived down to the present day.

If you could trace living lineages back far enough, you'd arrive at an organism that's the ancestor to every living thing: the last universal common ancestor, or LUCA. This idea has naturally led to a lot of speculation about what LUCA might have looked like. In the latest effort to offer some informed opinion, scientists have performed a clever genomic analysis to identify some of the genes that were probably in LUCA. Those genes, in turn, allow us to infer something about how LUCA lived and what environments it inhabited.

Building trees

Various analyses have indicated that organisms with complex cells (eukaryotes) are a relatively recent development on Earth—assuming you're willing to call something over two billion years old "recent." Two other lineages, bacteria and archaea, go back much further. LUCA sits at the point where bacteria and archaea started to diverge. So if you can identify genes that have been inherited by both of these lineages, they probably were present in LUCA's genome as well.