Extrapolation of noble gas partitioning studies to the plight of women in science

See my previous post for the context of this discussion, and links to both papers.

There are two chief explanations for why the representation of women in senior scientific research roles is lower than would be statistically predicted.

The “Harvard hypothesis” suggests that women are intrinsically worse at doing science.

The “feminist hypothesis” suggests that women are discriminated against in one or more direct or indirect ways.

This comparison of recent noble gas diffusion papers provides data with which one can compare these competing hypotheses.

With regards to the Harvard hypothesis, Veronika’s paper is clearly better science than Bruce’s. Thus this hypothesis is contradicted, not supported, by comparing these two research reports.

Whether or not the feminist theory is supported or refuted is hard to tell. Clearly, Bruce got a poorer quality paper into a higher profile journal, but whether gender played a role in his ability to do so is unclear. Bruce is a senior, well-respected professor, while Veronica is a (relatively) early career researcher. So Bruce’s ability to get his paper into the higher profile journal could be a result of seniority, experience at the publication game, networking, or his previous track record. I will leave it to the reader to speculate whether gender impacts on any of these things, but I will say this: The editorial board of Nature does not seem to have neutralized any of these potentially biasing factors.

Experimentally determined D values for noble gasses

Thermochronic recently blogged about a high profile paper that recently suggested that the partitioning coefficients for argon between mantle minerals and melts is greater than one (Watson et al. 2007). As it turns out, Heber et al. 2007, published earlier this year, suggests that the D values are actually between 10^-3 and 10^-4 for all noble gasses. The Heber et al. 2007 paper describes a very well-thought out and executed research program, reads like a detective novel, and is generally everything that a scientific paper should be.

They perform a standard partitioning coefficient experiment- slowly cool a melt to grow crystals, quench it, and measure the concentration of the trace element of choice in both melt and crystal to determine the ratio. The brilliant thing about this study is the depth of self-critizism and examination which they perform to identify and eliminate potential contaminants or non-equilibrium effects. This stands in stark contrast to the Watson et al. paper, where they pretty much assume that their results are right, and arrive at a value 10,000 to 10 million times higher than the Heber et al. paper.

I don’t want to ruin a gripping read, but the things that Heber et al. overcome include (but are not limited to): Room temperature diffusion of He out of the glass between experiment completion and analysis time, bubble formation, melt inclusions, very low concentrations. The interpretations of the paper are well supported by the data, but do include an explanation of how these numbers can explain “primordial” OIB noble gas ratios.

Although the noble gas partition coefficients are low (on the order of 10^-4), they are still 2 orders of magnitude higher than the partitioning coefficients of K, Th, and U, which are on the order of 10^-6 in a hartzburgitic system. Thus, although noble gasses are incompatable, they are not as incompatable as the radioactive sources for ⁴He and ⁴⁰Ar. So old depleted mantle will have a high primordial/radiogenic gas signature.

The fact that the Heber et al. and Watson et al. partition coefficients for argon differ by up to 8 orders of magnitude is striking. But I find the Heber et al. result more compelling, because the authors present, and then test, a dizzying array of potential complications in a rigorous manner. In contrast, Watson et al. make statements like,

“More generally, we believe that the inconsistency of our results and those of Broadhurst et al. with other experimental studies is due to the different experimental protocols used.”

While I have great respect for Professor Watson and his impressive research record, I am not interested in his beliefs, unless they are backed up by experimental evidence. And he makes no attempt to reconcile his results with previous work, much less try to disprove his own experiments. So a paper that dissects the potential causes of research discrepancies and addresses them is more convincing to me than one that relies on untested dismissals. As a final note, Watson et al. do not reference Heber et al. Heber et al. 2007 was published on 15 February, and available online since December 2006, while Watson et al. was not submitted until the beginning of May 2007.

References:
Veronika S. Heber, Richard A. Brooker, Simon P. Kelley, Bernard J. Wood. 2007 Crystal-melt partitioning of noble gases (helium, neon, argon, krypton, and xenon) for olivine and clinopyroxene. Geochimica et Cosmochimica Acta 71 1041-1061.

E. Bruce Watson, Jay B. Thomas, Daniele J. Cherniak 2007 40Ar retention in the terrestrial planets. Nature 449 299-304.

update: sociological speculations on these papers is here.

Feminist sulfates

I have been learning all sorts of new and interesting geology in my new life as an exploration geologist, but one of the things I recently read surprised even me. Economic geology tends to be a conservative, observation-based branch of the discipline. Ideology and activism are very seldom seen. So you can imagine my astonishment when I found papers and reports where barium sulfate suddenly started to self-identify as “Baryte”. Needless to say, I was somewhat taken aback. BaSO4 is an insoluble, highly stable mineral, with a solidly orthorhombic space group of Pbmm. It is not one to subject itself to trendy postmodern spelling fads.

On the other hand, the alkali earths are on the far left fringes of the periodic table, second only to the erotic alkali. So perhaps the insidious nature of political correctness has corrupted their vacant electron shells. And old Europe’s IMA has evidently endorsed the feminist spelling, despite the fact that no self-respecting red blooded American mineralogist would consider typing it.

Of course, being French, they can’t even be consistent with themselves. Despite listing “Baryte” as the correct spelling, the IMA still officially calls the nitrate salt “Nitro-barite”. And nowhere do they use the name “Baryum” for element 56. So forget the fact that the ancient Greeks spelled it with a y thousands of years before they knew what an element was, this is a matter of principle. Just like sphene. I’m with webminerals.com and American Mineralogist on this one. So barite it is, and those left-wing euro-trash crystalogists should consider themselves lucky that I don’t call hydrated calcium sulfate “gipsum.”

p.s. Microsoft Word doesn’t recognize “baryte”, so I must be right.

DIY Periodic Table

There are about a zillion periodic tables of the elements available in various formats and locations on and off the internet, but they never seem to actually have the info that one wants to see. Fortunately, Mr. Ash Norris, the electron probe technician at the Australian National University, has come up with a solution to this problem. He has a program that allows the user to print out a customized periodic table, containing whatever information one wishes to see. Check it out here.

World's fair meme

Here are five google search requests where this blog gets lucky:

sessile, omnivorous primates

thermodynamics of hot chicks

pseudoscience gender representation

hafnium is for lovers

Naked Mongols Always Slide Past Scantily Clad Argonauts

Full details here.

A380 take-off

Thanks to a weather delay, I was still at Sydney airport when the Singapore Airlines A380 took off for the return flight of the maiden commercial flight of the very big plane. It was fun to watch, but the really cool thing was the people watching.

Pilots coming off shift called home, saying they'd be late for dinner because they wanted to see the plane. All the guys on the tarmac who were supposed to be driving trucks or loading luggage all stopped, and positioned themselves for an ideal view. As for the plane itself, it was definitely bigger than a 747 (A british Air flight took off immediately afterwards), but it only looked really huge next to a 737 or other narrow body plane. It left the runway remarkably early for a plane of its size, but the climb angle was incredibly shallow- it took a very, very long time for it to disappear into the cloud deck.


There isn't a lot of old-fashioned, 20th century style bigger, faster, stronger engineering going on anymore these days, so it was cool to see a bit of it in action, in the form of the biggest passenger plane to enter service in 38 years.

Australia is supposed to get the first commercial dreamliner flights as well, but I doubt they will look as formidable. That's a 21st century plane.

I have pictures, but no way to post them at present...

Solar car race

Taking my fieldie to the airport this morning, we passed several cars racing in the World Solar Challenge. They were going slowly enough that they held up traffic- not surprising at 8:30 in the morning. Looking at the vehicles, we both thought the same thing- those cockpits must get HOT in the middle of the day. I doubt they have much in the way of air con. It turns out that the WSC has a blog. They might have pictures too- since I was behind the wheel, it wasn't practical for me to snap any.

Deadly Evapotranspiration

So, I seem to have missed the boat on this volume of the geologic carnival, as it has been published and lithified over at Shear Sensibility. But I’ll post anyway, as a philosophical exercise.

There are two endmember philosophies used to look at geologic processes, particularly those related to geomorphology. One is catastrophism, the idea that sudden, discontinuous, dramatic events are the driving force in shaping Earth history. The opposite is uniformitarianism. This school of thought suggests that the processes we can observe happening regularly today can explain all the geological events worth investigating. The dramatic nature of the current accretionary theme lends itself to catastrophism, so I will try to shift the balance by describing a process that is common, widespread, and deadly.

Evaporation, and its biological buddy, transpiration, are the basis for the hydrologic cycle. Without evaporation, we would have no rain, snow, rivers, glaciers, or humidity, and the earth would be a cold, dry, and barren place to live. But too much of anything can kill, and transpiration is no exception.



The playas shown above are an instance where persistent evaporation can become unhealthy. Here, on the northern edge of the Simpson Desert, evaporation reigns supreme, and there is little or no available surface water for most of the year. In such a climate, a person will transpire readily. However, without a source of water to rehydrate, this transpiration can rapidly turn fatal.

There are two ways transpiration can kill. The first is heat stroke. As the body loses water, it becomes more difficult to maintain a constant body temperature in hot conditions. If the body starts to overheat, and there is no available water for evaporative cooling, death can come quickly, as the brain starts to sustain permanent damage at temperatures much over 40 C.

Even if temperatures aren’t so hot, dehydration caused by transpiration can still cause death. Loss of fluids thickens the blood, and puts strain on a number of bodily organs, particularly the kidneys. Left untreated, it can cause organ failure and death.

I’m off for the final field campaign of the season (I hope). Working in the middle of a stable craton with very subtle relief, it is unlikely that volcanoes, earthquakes, mass wasting, or other catastrophic events will kill me. But every summer people in Australia are killed by the toasty end of the hydrologic cycle. I’ll try to make sure my crew doesn’t suffer that fate.

Later, y’all.