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December 2014 Archives

... and so here are a couple of compilations.

The first is Sciencealert's top 10 animal videos for this year. They include a lone porcupine seeing off a pride of 17 (!) lions; an octopus 'walking' on land (which is really really strange: it must take an awful lot of effort to do this, unsupported by water, & to what end?); and - reminiscent of someone slurping down spaghetti - a giant red leech engulfing an even larger earthworm

Or, if 'cute' is your thing, then try the year's 'top 10 cutest animals in science' from the Washington Post. In a win for video instruction, it seems that marmosets can learn new tricks by watching the instructor on video. I must take a compass with me when walking the dog, so that next time nature calls I can see if he's lining himself up with the earth's magnetic field! But I think the little koala wins on the squee! factor :) (Image credit Reuters/Daniel Munoz)

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Not necessarily. OK, most homeopathy's just water (or sugar pills), but if a non-self-limiting disease goes untreated because someone is relying on homeopathy then, yes, this 'remedy' could be said to have side effects.

Similarly, using powdered rhinoceros horn - prescribed as an oral dose in Traditional Chinese Medicine - is unlikely to have side effects on the dosed individual; after all, we can't digest keratin. Which makes this quote, from a post at, all the more poignant as it focuses attention on the wider impacts of magical thinking:

A common defense of Alternative Medicines is that they are side effect free. While the consumption of a tea made from a small piece of powdered rhinoceros horn may be as harmless and ineffective as biting your own fingernails, the side effects are far reaching and will be obvious for future generations who only know the rhinoceros from plaster molds along side those of dinosaurs in museums.


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In which we encounter - cow-tipping!

This is apparently the focus of both myth & mirth in the US: the idea that cows, asleep on their feet, are regularly tipped over by tipsy youths. Now, apart from the inconvenient little fact that cows tend to sleep lying down & thus are supremely untippable at that point in their daily rhythm, our bovine friends are large and solid and (with a leg at each corner) well-balanced. Nor do I imagine that Daisy would take kindly to a shoulder charge from an inebriated young man.

And indeed, at ModernFarmer, Jake Swearingen dissects this myth & imparts a little physics with along with the humour & the facts. It turns out that back in 2005 a couple of researchers ran the numbers & decided it would be impossible for a single person to overturn poor Daisy, but that two or more tippers could - theoretically - knock her off her feet. Provided that she did not see them coming, or negate their efforts by shifting her weight, that is.

And I loved one of the comments on the Atlantic's coverage of this story:

Lillie and Boechler are clearly unfamiliar with the conventions of this sort of work. As every mathematician or physicist ought to know, thought-experiment cows are universally spherical. And spherical cows are easily tipped, it's just that nobody can tell the difference. Now, if you've got enough drunken frat boys for a full-on game of Sleeping Cow Billiards...

Spoilsports may object that real cows aren't spherical. Neither are they rigid bodies, as is implicitly required by the Lillie-Boechler analysis. Each leg is hinged in two places, and depending on the resistance and range of motion of the joints, cow tipping could on purely physical grounds range from trivially easy to nigh impossible. If someone wants to instrument a live, sleeping cow and measure the muscular response to lateral disturbances, I'll wait. Someplace far away.

I'm sure you could factor this into a physics class somewhere, Marcus!

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Why is it that practically every time there's a new discovery relating to the evolution of our own species, there is a headline saying that this finding 'could rewrite human history'?

Because, bingo! At least one newspaper report1, of a paper published last week in Nature, carried the header: "Homo erectus engraving could re-write human history, and might show art began 300,000 years earlier than we knew." 

Now, the story's really interesting & surely didn't need the overblown headline, even if one of the research team was reported as using the phrase. Certainly the work of a large team of researchers (Joordens et al, 2014) has pushed back the dates for human use of symbols, to around 0.5 million years ago (on the basis of 40Ar/39Ar and luminescence dating), which is far older than the carvings and paintings of Cro-Magnons, and perhaps Neandertals - but doesn't necessitate a total rewrite of our history. And if their attribution of the finds to erectus is correct, then it extends our understanding of cognition in this species. (In fact, headlines like that fall right into the hands of creationists.)

This is a nice piece of detective work, & it also shows how serendipitous some discoveries can be: one of the team, Stephen Munro, noticed the marked mussel shell in photos he'd previously taken of specimens in a museum collection in Leiden, and that sparked a thorough investigation of the provenance and age of the shells. It turns out that the shell assemblage was originally collected at Trinil in Indonesia - the same location, and in fact the same strata (the 'main bone layer') as that of the 'type' specimen for H.erectus, collected in 1891 by Eugene Dubois. This led the team to the conclusion that this marked shell, and what looks like intentional damage to other shells, were the work of Homo erectus.

So what can we tell from these results? Well, it looks as if erectus enjoyed a good feed of seafood from time to time. The evidence for this lies in shells with holes in them - holes that lie over the position of the adductor muscle that holds the shell closed. Around 1/3 of the shells from this particular site had these holes, & overall the shell assembly contained "only large adult-sized specimens (about 80-120mm in length), while under normal conditions mussel populations contain all size classes" (Joordens et al, 2014): this strongly suggests that the molluscs were deliberately collected.

As for the holes themselves - the research team ruled out the possibility of damage by non-human predators, but noted that comparable holes were made in gastropod shells by pre-Hispanic modern humans living in the Caribbean. They went on to experiment on modern mussels and found that someone could use a tool such as a shark's tooth to drill a hole in the animal's shell over the adductor muscle; piercing the adductor caused the bivalve's shell to open. This speaks both to erectus' ability to conceive of and use rather smaller tools than we usually associate with them, and to their knowledge of shellfish anatomy. (You'd certainly find molluscs opened this way much easier to eat than if you had to bash them with a rock!) Another shell appears to have been retouched using a flaker, presumably for use as a scraper or other tool. 

The team then looked at the geometric lines found on the outer surface of one shell & determined that they were highly unlikely to be due to the shell knocking around with other shells & stones, but were probably produced using a shark's tooth or something similar. The lines were most likely laid down while the shell was fresh & so covered with the coloured periostracum common to mussels, "which would have produced a striking pattern of white lines on a dark 'canvas' " (ibid.) The lines are quite deep, would have required a fair bit of force and also good manual control to make, and Joordens & her colleagues concluded that "a single individual made the whole pattern in a single session with the same tool" (ibid.).

So, we've got evidence of what may be the earliest known use of a shell as a tool; evidence of Homo erectus including seafood in their diet; and evidence of someone consciously & deliberately scoring lines in a fresh mussel shell. But was it 'art'? And does it really necessitate the rewriting of our entire evolutionary history?


1 I'm not sure why the Independent reporter correctly identified the engraved lines as being on a shell & then went on to talk about them being on 'a rock'. Poor subbing?


J.C.A.Joordens, F.d'Errico, R.P.Wesselingh, S.Munro, Vos, J.Wallinga, C.Ankjaergaard, T.Reimann, J.R.Wijbrans, K.F.Kuiper, H.J.Mucher, H.Coqueugniot, V.Prie, I.Joosten, B.van Os, A.S.Schulp, M.Panuel, V.van der Haas, W.Lustenhouwer, J.J.G.Reijmer & W.Roebroeks (2014) Homo erectus at Trinil on Java used shells for tool production and engraving. Nature  doi: 10.1038/nature13962, published on-line 3 December 2014

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Is it a peacock? Is it a turkey?

Another in the occasional series of gorgeous creatures: the ocellated turkey :)

Image credit:

Over on Tetrapod Zoology, Darren Naish provides the detailed story of this species' biology & evolution.

Apparently they are difficult creatures to keep in captivity, so they won't be appearing on the Christmas menu any time soon. They're native to an area of about 130,000 square km across northern Belize, northern Guatemala, and the Yucatan peninsula.

When I first saw an image of this stunning bird (on FB, as one might expect) I thought I was looking at the male of a strongly dimorphic species. However, it turns out that both sexes share this spectacular colour pattern, although the colours may be somewhat muted in females. They're easier to distinguish in the breeding season, because the red & yellow lumps, or nodules, that dot the head & neck swell in males & become even more brightly coloured.

Sadly, as Matt Milner notes on the Cool Green Science blog

Most conservationists consider it near-threatened, with deforestation making the birds easier to kill by local subsistence hunters, a major factor in the species’ decline. 

The North American wild turkey got pushed close to the brink of extinction in New York state & has since bounced back due to careful management of the population and it's habitat, so there's hope for its gorgeous cousin if suitable conservation mechanisms can be identified & put in place.


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I loved playing with kaleideoscopes when I was (much) younger, but the images they produce have nothing on what Victorian microscopists achieved using diatoms.

Diatoms are single-celled photosynthetic organisms, and one of the things that really makes them stand out it the variety & beauty of their cell walls, which contain a very high proportion of silica: as the Tree of Life site says, they basically live in glass boxes. Collectively the diatoms make up one of the largest taxa on earth, one with considerable ecological significance: at about 40% of marine primary production, they produce >20% of our oxygen.

But back to their cell walls. Apparently, Victorian scientists were big on arranging these little organisms in complex patterns that derived much of their beauty from the cell walls found in different species. While the actual details of what they did weren't recorded, Neatorama describes the work of Klaus Kemp, who has rediscovered their art & generated some stunning images of his own.

Images like this: 

(Image credit: Klaus Kemp)

And watch the video here. This is wonderfully skilful work, & so beautiful, and I'll share it with my students in next year's classes.

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When I was a kid - & we're talking a looong time ago now! - we had a gorgeous Advent calendar that was designed to look like a renaissance-era painting. At least, that's how I remember it. And there was certainly none of this new-fangled stuff involving chocolate behind the little doors!

But Advent calendars have come a long way since then, & now you can view them on-line. And thus it was that, after an enjoyable sojourn on the animated happiness of the Wellington city version, behold! I came at last to the 2014 Chemistry Advent Calendar. And I found it to be good, and learned about carotoxin (&, by trotting off down one of the internet's distracting sidepaths, about liquorice rot. Which affects carrots, not liquorice). However, unlike the traditonal version, you can't cheat by secretly prying open a 'future' door to see what's concealed within - you'll just have to go back every day :)

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This is a really difficult post to write. The word 'cancer' evokes any number of fears & unpleasant images, and I can't imagine something worse than discovering that a child has cancer. (Nor can I be certain of my own reaction, if I should find myself in that position.) But that doesn't excuse credulous reporting on the issue, most recently exemplified in this story (in the 'Life & Style' section) in the NZ Herald.

The story is about the use of plant-based compounds, called salvestrols, for children who've been diagnosed with a range of cancers. Now, a search for 'salvestrols' brings up a rather large number of websites making all sorts of claims for their efficacy, but a search for 'scholarly articles' narrows things down a bit. The first such paper to come up appears to be the one used to support the claims made by the Herald piece, & was published in the Journal of Orthomolecular Medicine in 2007. (It's worth noting that this particular field of study is not widely supported by science-based medicine and that the journal itself isn't indexed by Medline. I was intrigued to see that the editor of JOM has compared it to Medical Hypotheses, because really, that's not a good advertisement.)

Those claims include the hypothesis that salvestrols are used by our bodies to destroy cancer cells (referencing an earlier study by the same authors) and that modern practices around food-growing & preparation reduce the amount of salvestrols in our diet (with little evidence for this cited in support). Unfortunately the Herald's reporter simply presented these ideas as if they are widely-accepted facts: 

they trigger a process in the body allowing it to kill diseased cells. But they have been depleted from food through modern farming and production techniques which have drastically altered diets.

The paper itself discusses case studies ie there are no controlled trials; while the case studies may suggest routes for future research they should be viewed as tentative, at best. Further, it makes the following claim:

First, it is not harmful. The toxins produced through the metabolism of Salvestrols by CYP1B1 are confined to the cancer cells and are exhausted through the destruction of the cell.

And yet GSK stopped a trial of a salvestrol (reservatrol) in cancer patients because not only was there no evidence of efficacy, there was evidence of harm (kidney damage). Hardly suprising as compounds such as reservatrol appear to have an effect on quite a range of metabolic pathways in our bodies. 

Now, that information was fairly easy to find, so it was really, really disappointing to see the Herald's reporter referencing the JOM - and the British Naturopathic Journal - as being the best source of information on this subject.

It's also important to note that the people identified in the Herald story as successfully using salvestrols as a cancer treatment have also had surgery & in some cases chemotherapy as well. It's entirely possible that the medical treatments alone have resulted in patients being in remission - and without properly-designed clinical trials there's no way to identify any impact of the plant compounds. Nor is it enough to say that it's "common sense" that they work; as a colleague's said to me, blood-letting was also seen as a common-sense treatment for pretty much everything that ailed you.

This isn't the first time that we've seen such poor reporting around such a serious issue; sadly, I suspect it won't be the last. 


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Actually, that's a bit of a fib as the zombies & the lego don't actually meet in these videos :) But both have a science focus.

Lego is the focus of a clip called 'Building Curiosity', which is something of an ode to science; I rather enjoyed it.

And the zombies? Well, you're likely to encounter the animated undead on a place like the Discworld, where they tend to have an issue with bits falling off at inopportune moments. But the flesh-eating urge? Just might be possible...


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