Geology February 2017
Silicified glendonites in the Ediacaran Doushantuo Formation (South China) and their potential paleoclimatic implications
Another guilty confession of geological ignorance, as I had never heard of glendonite or its precursor ikaite. It works like this: in water just above freezing, calcium carbonate will precipitate out as the hexahydrate – CaCO₃ • 6H₂0. Ikaite is a rather spectacular looking mineral in nature, with lots of spikey crystals protruding from a central mass, but you won’t see it in any mineral collection in the world because it almost immediately loses its water and changes to calcite if it’s removed from ice water. However, now and then some other mineral that isn’t metastable will replace ikaite; the result is a “pseudomorph”. In the case discussed here, the pseudomorph mineral is ordinary calcite, and the resulting thing has the shape of an ikaite crystal but the internal crystal structure of calcite and is called glendonite; to make it even more complicated the glendonite has since been replaced by silica, thus resulting in a pseudopseudomorph. At any rate, the authors’ point in all this is that ikaite can only occur in really cold water, and thus the Doushantuo Formation – which is known for things that might be embryonic metazoans or colonial protists or just weird giant bacteria – must have been deposited in really cold water.
An urban collection of modern-day large micrometerorites: Evidence for variations in the extraterrestrial dust flux through the Quaternary
I know we had a thread somewhere about using a magnet to pick micrometeorites out of your downspout flow. The authors of this article note that this idea is popular with amateur astronomers but dismissed by professionals, because the number of supposed micrometeorites decrease with distance from an urban center, implying that they are terrestrial products of combustion rather than cosmic dust. However, they sampled gutters in Oslo and found out of 500 suspect micrometeorites (found by magnetic separation), 48 turned out the be actual micrometeorites as evinced by microscopic analysis (most were olivine rather than iron, but had enough iron for the magnetic separation to work). The authors note that the micrometeorite abundance is consistent with micrometeorites collected from other environments (ocean sediment and glacial ice) but the ratio of barred olivine (parallel plates of olivine surrounded by crystalline olivine) to cryptocrystalline spherules is higher for the Oslo micrometeorites than the other samples. Since the Oslo sample is quite recent (average age estimated a 6 years based on the roof ages) while the other samples are much older (in the 200 ka range) the conclusion is the composition of micrometeorite dust has changes recently.
Natural History February 2017
A Tangled Food Web
Chloroviruses attack green algae. Some algae escape by living inside paramecia. However, if the paramecia are eaten by copepods, the algae are excreted undigested and can then be attacked by the virus. The research provides a reason for previously unexplained cycles in algal abundance in freshwater lakes.
Out of Place
The author was hiking on the Isle of Man when he encountered a pair of wallabies. Apparently wallabies escaped from a nearby wildlife park in the 1970s and have established a breeding colony.
Paleobiology issue 1 2017
Identifying flight parameters of Mesozoic avians through multivariate analysis of forelimb elements in their living relatives
Modern birds have various “flight styles” – continuous flapping, flap and gliding, flap and bounding, thermal soaring and dynamic soaring. A modern bird can be reliably assigned to a flight style using its wing loading and wing aspect ratio; however, these cannot be reliably deduced from fossil specimens. The authors used principal components analysis to identify fossilizable features – forelimb bone dimensions – that could be worked backward to identify flight styles. Mesozoic birds exhibit all the flight styles of modern birds except dynamic soaring.
Science 27 January 2017
Europe to open first body farm
The United States has six body farms, where corpses are left out in the open to study decomposition under natural conditions, for forensic determinations. Now one has been opened in the Netherlands. The short note comments gratuitously that the European body form is located “adjacent to a Kentucky Fried Chicken franchise”.
Tight regs for gene-edited animals
The FDA proposes to regulated gene-edited animals by the same standards used for veterinary drugs. Researchers expressed dismay, noting that this means milk from gene-edited hornless dairy cattle will have to go through the same approval process as a new drug.
News in depth
Metallic hydrogen created in diamond vise
High-pressure physicists at Harvard claim to have created metallic hydrogen in a diamond anvil vise, at a pressure of 495Gpa. Others are skeptical, noting that it’s possible the hydrogen reacted with the gasket material in the anvil. There is some speculation that metallic hydrogen may be metastable; the researchers want to do more measurements before the release it from the anvil and find out.
Regulators drop controversial biospecimen consent proposal
Back in 2015 the DHHS proposed a revision to the rule on consent for human subjects. Previously, once a subject had provided consent – to do research on a blood sample, say – the consent applied to subsequent research as well. Under the proposed rule, written consent would have to be obtained again for any subsequent research. The proposed rule was dropped on January 18 2017.
Challenges in researching terrorism from the field
Academics note that the US response to terrorism has generally treated it as a military or criminal activity. For example, the military approach often involves “cost imposition” strategies; it’s noted these are unlikely to deter a suicide bomber. Similarly, treating terrorism as a criminal activity ignores the fact that most criminal activity does not involve low-probability high-impact events, deliberate targeting of anonymous civilians, and support from the noncriminal population. While criminologists have developed checklists to profile various types of crime (the article cites securities fraud and serial killing), these don’t seem to work for terrorists. However, it’s noted that rules designed to protect human research subjects make very little sense when applied to terrorists. For example, a captured terrorist suspect cannot be interviewed under academic research standards for human subjects; a domestic criminal can be interviewed if there is a representative on the university’s review board, but US law does not allow this for terrorism suspects. It’s noted the success of ISIS is due in part to its own field research on how to recruit subjects.
Gender stereotypes about intellectual ability emerge early and influence children’s interests
The researchers studied children with various games and tests, using the “child-friendly” term “really, really smart”: for example, they were shown pictures of men and women matched for dress and other attributes and asked to guess which one was “really, really smart”. By age 6, girls were more likely to identify the male in the couple as “really, really smart”. The girls were alos more likely to avoid playing games if they were told they were for “really, really smart” children (the control group was told the game was for children that “worked really, really hard”).
Nature 26 January 2017
News in focus
Boost for CRISPR challenger
A Danish company has purchased rights to a gene editing tool, NgAgo, developed at a Chinese university. NgAgo was originally described as more efficient and versatile than CRISPR. However, enthusiasm for NgAgo as diminished as other researchers were unable to duplicate results, and the publisher of the original NgAgo paper (Nature Biotechnology) published an “expression of concern”.
Reform predictive policing
We’ve had some threads on “predictive policing”: using software to predict where crimes might occur. Critics argue that the proprietary algorithms are biased against minorities and the Nature article provides some evidence to support this. It’s noted that the software could be applied “in reverse” – for example to identify officers who exhibit racial bias in arrest patterns.
News & Views
Earth’s building blocks
The isotopic nature of the Earth’s accreting material through time
Ruthenium isotopic evidence for an inner Solar System origin of the late veneer
It’s been assumed that meteorites represent the material the Earth came from, particularly the carbonaceous chondrite class of meteors. It turns out the isotopic and chemical composition of carbonaceous chondrites doesn’t work. When the core differentiated from the mantle, it should have selectively removed iron-soluble metals from the mantle. However, the mantle is much less depleted (compared to meteorites) than expected. The explanation for this is that more material was added after the core differentiated (the “late veneer”); most likely by the class of meteorites know as enstatite chondrites. The trouble with this is although the isotopic composition of enstatite chondrites matches well with the composition of the Earth the bulk chemical composition is very different from accessible rocks (crust and upper mantle). That would imply that the deep Earth interior most have a very different composition that upper layers. Note and two articles.
Observation of the 1S-2S transition in trapped antihydrogen
One of the puzzles about matter is why there is so much of it; most theories of the Big Bang imply there should be equal amounts of antimatter and matter. There are various explanations why this might be so; on is that there is some subtle physical difference between matter and antimatter. The authors tested this by “trapping” antihydrogen atoms (positron and antiproton) and lasering them so they would emit light; the result is the spectrum of antihydrogen agrees with the spectrum of hydrogen to one part in 10**-10.
A solution to the single-question crowd wisdom problem
The authors note the “wisdom of crowds” has itself become a piece of crowd wisdom, and that it works quite well for a variety of questions. However, democratic choice ignores specialized knowledge that is not widely shared. The propose an adjustment to crowd voting to correct for this: the SP (for “surprisingly popular”) algorithm. Instead of asking people to vote directly on the answer to a question, the crowd is asked to vote on how popular they thought various answers would be and their confidence in their answer. The “surprisingly popular” answer) – the one more popular than predicted – is most likely to be correct. As an example, for the question “Is Philadelphia the capital of Pennsylvania” most voters answer “Yes” (presumably assuming Philadelphia is the capital) but voters who answer “No” (presumably because they know Harrisburg is the capital) have more confidence in their answer; thus “No” is surprisingly popular and the correct answer.
Science 13 January 2017
Starshot has ESO telescope time
The Breakthrough Starshot project, which is supposed to send a fleet of tiny laser-launched spacecraft to Alpha Centauri, has just bought telescope time and paid for improvements on the European Southern Observatory Very Large Telescope in Chile.
News in Depth
Life-saving diphtheria drug is running out
There might be more of this going on now that vaccines have become politically incorrect. Diphtheria is caused by a bacterial endotoxin. Before vaccination, the treatment was an antitoxin. You make this by injecting a horse with a small amount of the toxin; the horse makes antitoxin; you separate it out of the horse blood and give it to the diphtheria patient. On March 17 a 3-year girl died in hospital in Antwerp. The girl was from Chechnya and had never been vaccinated. There was no antitoxin in Belgium; a call was sent out all over Europe and eventually some was found in the Netherlands. Unfortunately it arrived too late for the little girl. Diphtheria has been so rare that there was no profit in it, and PETA has called for the elimination of the use of horses as “living factories” (To be fair to PETA, they are funding research to make the antitoxin in cell culture).
A matter of tree longevity
Trees are supposed to be one of the cures for carbon dioxide. This article notes there’s no long term gain; trees use carbon dioxide as they grow but an equal or near equal amount is released when the tree dies or is harvested. Thus trees do not ”sequester” carbon in usual sense of the world but merely store it temporarily.
Nature 17 November 2016 (slipped down in the stack somehow)
News in Focus
Why the polls missed Trump
The simple answer is Trump voters were more enthusiastic than Clinton voters about turnout and less enthusiastic than Clinton voters about responding to polls. The Pew Research Center found it amazing that many polls with different methodologies all had errors in the same direction. It was noted that this election had a record low number of people who would admit who they were voting for to pollsters.
Tidal evolution of the Moon from a high-obliquity, high-angular momentum Earth
The Late Giant Impact hypothesis is the current leader among contestants for forming the Moon, but we have a couple of threads on problems with it. One is that past models don’t have a good way of getting rid of the angular momentum such an event would produce. This paper models an impact that leaves a rapidly spinning Earth with high obliquity (i.e., the axis of rotation is tilted out of the plane of the ecliptic much more than it is now), noting that tidal effects would quickly (50Ma) change an initial obliquity of 60-70° and a 2 hour rotation period to stable conditions.
Nature 10 November 2016
UK pollution case
The environmental law activist group Client Earth successfully sued the UK government for using an “over-optimistic” model for nitrogen dioxide.
The European Commission announced plants and plant products created using conventional breeding methods (i.e., not GMOs) are not patentable. This is contrary to the position of the European Patent Office, which says they are.
News in Focus
Tracker flags failures to report trial results
Computer searches of the ClinicalTrials.gov database showed 45.2% of 26000 clinical trials produced no publishable results. The trails were matched with results published in PubMed. The computer tool authors note that their program might miss trials published in journals not indexed by PubMed. News item and longer note.