Experiment measures the times that it takes an electron to quantum tunnel in and out of a helium atom and a carbon dioxide molecule — ingenious technique and excellent lay science writing

Citation — to the study

Dror Shafir, Hadas Soifer, Barry D. Bruner, Michal Dagan, Yann Mairesse, Serguei Patchkovskii, Misha Yu. Ivanov, Olga Smirnova, and Nirit Dudovich, Resolving the time when an electron exits a tunnelling barrier, Nature 485(7398): 343–346(17 May 2012) doi:10.1038/nature11025

Citation — to Bob Yirka’s excellent lay explanation of how the study was done

Bob Yirka, Research team devises a means for measuring quantum tunneling time, Phys.org (18 May 2012)

Just about the best explanation of an aspect of quantum physics as I have ever read

It takes a sharp intellect and good writing to clarify difficult phenomena for lay readers.

After you read the following, you might think, “What was so hard about that?”

And that is exactly my point about science writer Bob Yirka’s communication ability:

Quantum tunneling is where particles are able to move through a barrier even though they lack sufficient energy to do so.

It’s also a process that happens at such speed that it’s been almost impossible to measure. Making things even more difficult is the fact that measurement of the speed of tunneling is described differently depending on whether it is inside or outside of its barrier.

Outside, the speed at which a particle moves is described by normal Newtonian physics.

Inside of its barrier however, it’s described by a complex number, which is calculated by combining a real and imaginary number.

Making things even murkier is the fact that particles such as electrons don’t exist in a single state, but rather as a quantum wave, which is described by a wave function.

© 2012 Bob Yirka, Research team devises a means for measuring quantum tunneling time, Phys.org (18 May 2012) (paragraph split)

What the experimenters did to measure the time that it takes a helium electron to tunnel

The barrier in this case was a helium atom’s normal state, in which electrons can’t just fly away and leave the helium atom alone with its positive charge.

Note

You’ll recall from chemistry that a helium nucleus — also called an alpha particle — consists of two protons (positively charged) and two neutrons (neutral).

In its “neutral” configuration, the helium atom has two electrons (each with a minus one charge) that together balance out the nucleus’ 2+ proton charge.

The issue here was to see how long it takes for an electron to tunnel its way out of (or back into) the atom.  In effect, the electron will be tunneling away from (escaping) the attraction imposed by the protons’ attractive positive electrical charge.

Yrika explains how the research team accomplished these measurements.  They used a laser field to slightly lower the energy with which the protons held onto the atom’s electrons.  The electrons were therefore able to “tunnel” their way out.

Then, to get the electrons back into the atom, the team used a slightly less energetic laser to “push” them back.

When the electrons return to the normal atomic state, the atom releases a photon that conveniently has more energy than the initial laser field.  Therefore, it can be distinguished from the background.

By being able to control both ends of the tunneling process (“out” and “in”), the team could measure the time it took electrons to tunnel.

These tunneling times are measured in attoseconds.

Note

An attosecond is 1 x 10-18 second.

According to Wikipedia, this is the time that it takes light to travel the distance represented by three adjacent hydrogen atoms.

Then the researchers repeated the experiment with electrons from different energy levels (orbitals) in a carbon dioxide atom

You’ll also remember from chemistry that electrons are held to complex atoms (or molecules) in probablistically layered orbitals.  Overcoming these requires increasing amounts of energy, the “deeper” toward the nucleus one goes.  In other words, it is easier to strip outer orbital electrons than inner ones.

The research team took advantage of this characteristic by timing the difference in time that it took for outer carbon dioxide (CO2) electrons to tunnel versus those two “layers” deeper.

 Compare how Bob Yrika explained this with what the researchers said in their abstract

The scientists wrote:

Here we study laser-induced tunnelling by using a weak probe field to steer the tunnelled electron in the lateral direction and then monitor the effect on the attosecond light bursts emitted when the liberated electron re-encounters the parent ion.

We show that this approach allows us to measure the time at which the electron exits from the tunnelling barrier.

We demonstrate the high sensitivity of the measurement by detecting subtle delays in ionization times from two orbitals of a carbon dioxide molecule.

© 2012 Dror Shafir, Hadas Soifer, Barry D. Bruner, Michal Dagan, Yann Mairesse, Serguei Patchkovskii, Misha Yu. Ivanov, Olga Smirnova, and Nirit Dudovich, Resolving the time when an electron exits a tunnelling barrier, Nature 485(7398): 343–346(17 May 2012) doi:10.1038/nature11025 (paragraph split)

The team delivered the same information that Bob Yrika did, but less understandably.

This demonstrates the value of excellent science writing to public understanding.

The moral? — There are three loosely related to this one experiment

That we can actually measure attoseconds boggles the mind.

Ingenious science techniques delight the intellect.

Good lay science writing is essential to public comprehension.

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Published:
18 May 2012 – 08:41
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By BrainiYak
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Study suggests that trees sequester less carbon dioxide than climate models expected — by about 3 percent

Citation

William L. Bauerle, Ram Oren, Danielle A. Way, Song S. Qian, Paul C. Stoy, Peter E. Thornton, Joseph D. Bowden, Forrest M. Hoffman, and Robert F. Reynolds, Photoperiodic regulation of the seasonal pattern of photosynthetic capacity and the implications for carbon cycling, Proceedings of the National Academy of Sciences [PNAS], doi: 10.1073/pnas.1119131109 (14 May 2012)

Number of light hours versus the effects of warm temperatures

From the abstract:

We show that photoperiod explains more seasonal variation in photosynthetic activity across 23 tree species than temperature.

Although leaves remain green, photosynthetic capacity peaks just after summer solstice and declines with decreasing photoperiod, before air temperatures peak.

In support of these findings, saplings grown at constant temperature but exposed to an extended photoperiod maintained high photosynthetic capacity, but photosynthetic activity declined in saplings experiencing a naturally shortening photoperiod; leaves remained equally green in both treatments.

© 2012 William L. Bauerle, Ram Oren, Danielle A. Way, Song S. Qian, Paul C. Stoy, Peter E. Thornton, Joseph D. Bowden, Forrest M. Hoffman, and Robert F. Reynolds, Photoperiodic regulation of the seasonal pattern of photosynthetic capacity and the implications for carbon cycling, Proceedings of the National Academy of Sciences [PNAS], doi: 10.1073/pnas.1119131109 (14 May 2012) (paragraph split)

The correction to previous estimates of carbon sequestration is only about 3 percent — and the finding implies that increased warming will not boost forest-based carbon sequestration

Colorado State University’s press release indicates that this finding indicates that estimates for the global sequestration of carbon have to be reduced by only 3.4 percent.

Perhaps more interesting, global warming will not result in a hypothesized boost in forest-based carbon sequestration:

 “Our findings mean that lengthening growing seasons with global warming will not increase photosynthesis, because day length will not change,” [co-author Ram] Oren said.

© 2012 Coleman Cornelius, Study shows trees absorb less carbon than earlier thought; Leaf activity drops during summer, Today @ Colorado State – Colorado State University (14 May 2012)

The moral? — the forest carbon sink’s hoped for counter to warming may not work

Not only does this study take away 3 percent of forests’ indirect counter to warming, it also presumably removes most of the hoped for boost in tree-based photosynthetic sequestration that some had predicted would occur with increasing temperatures.

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Published:
16 May 2012 – 08:22
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By BrainiYak
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NASA’s Interstellar Boundary Explorer (IBEX) shows that the expected bow shock at the outer edge of solar system’s heliosphere is not actually there — and Voyager 1 and 2’s continuing missions demonstrate that the heliopause is shaped differently than expected

Citation

D. J. McComas, D. Alexashov, M. Bzowski, H. Fahr, J. Heerikhuisen, V. Izmodenov, M. A. Lee, E. Möbius, N. Pogorelov, N. A. Schwadron, and G. P. Zank, The Heliosphere’s Interstellar Interaction: No Bow Shock, Science Express, DOI: 10.1126/science.1221054 (10 May 2012)

What is IBEX?

NASA launched the Interstellar Boundary Explorer on 19 October 2008 to investigate what happens when the solar wind, that defines the heliosphere, impacts interstellar space at the edge of the solar system at the heliopause.

The spacecraft measures neutral (non-charged) atoms.

What is the heliopshere and where does it end?

The heliosphere is essentially the bubble of solar wind that flows out from the sun and surrounds the solar system.  The wind travels outward at about 1.6 million kilometers per hour (1 million miles per hour) before it runs out of “oomph” where it runs into the material and radiation that define the rest of the cosmic neighborhood:

The ionized solar wind flows continuously outward at speeds of ~300-800 km s−1, incorporating interstellar neutral atoms that flow into the heliosphere and are ionized to become pickup ions.

Because the solar wind and surrounding local interstellar medium are both magnetized plasmas and cannot penetrate each other, the solar wind inflates a bubble in the local interstellar medium called the heliosphere.

Inside its boundary—the heliopause—there is a termination shock, where the solar wind and pickup ions are compressed and heated.

Because the heliosphere moves with respect to the local interstellar medium, the dynamic pressure plays an important role in shaping the heliosphere, with a compressed “nose” on the upwind side and a downwind “tail”.

© 2012 D. J. McComas, D. Alexashov, M. Bzowski, H. Fahr, J. Heerikhuisen, V. Izmodenov, M. A. Lee, E. Möbius, N. Pogorelov, N. A. Schwadron, and G. P. Zank, The Heliosphere’s Interstellar Interaction: No Bow Shock, Science Express, DOI: 10.1126/science.1221054 (10 May 2012) (paragraph split and acronyms removed)

Facts sometimes trump our expectations

The above team has done calculations that indicate the expected bow shock at the forward terminal end of the heliopause is not actually there.

In the past, scientists had expected three zones at its forward end: termination shock, heliopause, and bow shock.  Now, it appears that bow shock does not occur because the solar system is traveling more slowly against the interstellar medium than previously thought:

That difference in speed, about 7,000 miles per hour (11,000 kilometers per hour), does not sound like much but it means that there is about 25% less pressure in the region in front of our heliosphere.

What this also means is that there is not the right combination of density, speed, pressure, and magnetism to cause a bow shock to form.

© 2012 David McComas, From Dave McComas, IBEX Principal Investigator, NASA, Southwest Research Institute — IBEX, Interstellar Boundary Explorer (10 May 2012)

Citation — to diagrams of the heliosphere, termination shock, heliopause, and non-existent bow shock

David McComas, From Dave McComas, IBEX Principal Investigator, NASA, Southwest Research Institute — IBEX, Interstellar Boundary Explorer (10 May 2012)

Voyager 1 and 2’s contribution

Last year, I wrote about the continuing utility and longevity of 1977’s two voyager spacecraft, here.  Recently, the two spacecraft sent back data that shows that the heliopause is not as symmetrically shaped as it was expected to be.

Dr. McComas’ above-linked press release contains a diagram that shows the asymmetrically squashed shape that the bubble (now) seems to take. He hypothesizes that this distortion is due to comparatively strong interstellar radiation coming at it from off-axis.

An added tidbit — Dr. McComas’ merry-go-round analogy

I had wondered why, in regard to the asymmetry of the heliopause’s frontal boundary, we had assumed that the solar system would necessarily be moving in the direction of maximal incoming interstellar radiation.

Dr. McComas tossed in an analogy that indirectly explains the complexity of making these calculations:

As our Sun orbits the center of the galaxy every couple hundred million years, it bobs in and out of the disk of the galaxy like a horse on a merry–go–round.

As it does this, it passes through areas of the interstellar medium that are more and less dense, causing the heliosphere to change in shape and size.

Denser areas with larger speeds relative to the Sun can compress the heliosphere more, while slower and less dense regions allow the bubble to expand.

© 2012 David McComas, From Dave McComas, IBEX Principal Investigator, NASA, Southwest Research Institute — IBEX, Interstellar Boundary Explorer (10 May 2012)

The moral? — Our best guesses often don’t harmonize with the facts

Which encourages us to continue our childlike looking around.

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Published:
14 May 2012 – 14:17
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By BrainiYak
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Thinking in 3 dimensions explains why some of BP’s Deepwater Horizon spilled oil did not wind up when and where predicted — the effects of water mounding

Citation

Frederico Falcini, Douglas J. Jerolmack, and Bruno Buongiorno Nardelli, Mississippi River and Sea Surface Height Effects on Oil Slick Migration, PLoS ONE 7(4): e36037, doi: 10.1371/journal.pone.0036037 (27 April 2012)

Contrasting water and oil densities explain how water mounding fended oil away from Louisiana’s Mississippi River Delta shores

From the University of Pennsylvania’s press release:

Using publicly available datasets, their study reveals that the force of the Mississippi River emptying into the Gulf of Mexico created mounds of freshwater which pushed the oil slick off shore.

“The idea is that, if the water surface is tilting a little bit, then maybe the oil will move downhill, sort of like a ball on a plate. If you tilt the plate, the ball will roll one way and then another,” [co-author Douglas] Jerolmack said.

“Surprisingly no one had really investigated the effect that the tilting of the water surface can have on the migration of oil.”

© 2012 Penn News, A Push From the Mississippi Kept Deepwater Horizon Oil Slick Off Shore, Penn Research Shows, University of Pennsylvania (10 May 2012) (paragraph split)

Shared data made this research both possible and necessary

During the Deepwater Horizon oil spill, the National Oceanic and Atmospheric Administration produced aerial images of the oil’s movement in the Gulf of Mexico.  NOAA tried to forecast where the spill would go by using computer models of ocean currents.

These models proved to be unreliable.  The oil’s movements were being affected by more than just oceanic and wind currents.

To find out what was going on, Jerolmack’s group looked at sea-surface levels that had been recorded in real time by the Colorado Center for Astrodynamics Research.  (These are calculated by radar from the Ocean Surface Topography Mission’s Jason-2 satellite.)

The research team had to separate the land surface’s confounding effect from the raw data.  Once done, they recognized that the Gulf of Mexico exhibited water mounds and valleys, where the water surface was higher in some areas and lower between them.

The Delta “bump”

One obvious bump elevated the sea surface at the Mississippi Delta.  This was apparently due to the river’s annual spring flood, which delivers a large volume of fresh water into the Gulf:

This powerful discharge of fresh water mounded on top of the denser salt water of the Gulf.

The resulting bulge, which was approximately 10 centimeters higher than the surrounding ocean and 50-100 kilometers in diameter, was positioned so that oil from the Deepwater Horizon drilling rig ran “downhill” and away from the coast.

© 2012 Penn News, A Push From the Mississippi Kept Deepwater Horizon Oil Slick Off Shore, Penn Research Shows, University of Pennsylvania (10 May 2012) (paragraph split)

Jerolmack added that mounds can only form when the river discharge is high and the ocean is calm.  When the spring flood ended, the oil spill began moving landward again.

A computer model of 2-layer liquids confirmed the team’s interpretations.

The moral? — Shared data provides unforeseen and useful findings

Which is why the increasing push for proprietary-based restrictions on the movement of scientific data is harmful.  And government research and data collection remain so integral to the nation’s science base.

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Published:
11 May 2012 – 13:14
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By BrainiYak
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Experimental research on rare genetic disease in children reportedly revealed an absolutely critical enzyme (RNAse H2) for surprisingly routine DNA repair — who would have “thunk” it?

Citation

Martin A.M. Reijns, Björn Rabe, Rachel E. Rigby, Pleasantine Mill, Katy R. Astell, Laura A. Lettice, Shelagh Boyle, Andrea Leitch, Margaret Keighren, Fiona Kilanowski, Paul S. Devenney, David Sexton, Graeme Grimes, Ian J. Holt, Robert E. Hill, Martin S. Taylor, Kirstie A. Lawson, Julia R. Dorin, and Andrew P. Jackson, Enzymatic Removal of Ribonucleotides from DNA Is Essential for Mammalian Genome Integrity and Development, Cell, doi: 10.1016/j.cell.2012.04.011 (early online publication, 10 May 2012)

You would think we would know something about a process that occurs more than a million times as a cell divides

A common enzyme appears to fix errors in DNA replication that occur roughly a million times with each cell replication.  Without it, we would mostly all be dead.  Yet, it has taken this long to identify the extent of the enzyme’s reparative function.

What the research team was doing had nothing to do with making this discovery

Researchers at the University of Edinburgh were trying to pin down the causes of the very rare, autosomal recessive (genetic) pediatric disease called Aicardi-Goutières syndrome.

The syndrome is one of a group of white matter brain diseases called leukodystrophies.  The term refers to defects in the development of the insulating myelin sheath that surrounds nerves.

The research team already knew that Aicardi-Goutières was caused by mutations (defects) in what are called RNase H2 genes.

But they wanted to see how these defects caused the disease.  In pursuing their inquiry, they implemented a common genetic technique that experimentally “knocks ” the gene being studied “out” of the genetic code of the animal (or plant) under review in the lab.  These altered critters are then called “knockouts.”

Knockouts are valuable for pinning down exactly what a gene (and its products) do.  Presumably the animal that lacks the gene will demonstrate a loss of function — or a corresponding development of something abnormal — as compared with normal organisms.

So here, the Edinburgh team removed the RNase H2 genes in mice.  That way they could see the full effect of what happens, when the genes are not only mutated, but completely gone.

Findings

The shocker:

They found that without the enzyme, the developing mouse embryos accumulated more than 1,000,000 single embedded bits of RNA in the genome of every cell, resulting in instability of their DNA.

© 2012 Medical Research Council – Institute of Genetics and Molecular Medicine, Enzyme corrects more than one million faults in DNA replication, University of Edinburgh (via Phys.org) (10 May 2012)

Why this matters

Obviously, DNA genetic coding will not work very well, when other substances (like chemically similar RNA) get incorporated into it.  That is analogous to having stray letters wander into the words on a page.  The resulting gobbledygook is going to be difficult to read.

With DNA, if something important cannot be read properly, either a gene product is not made at all or it gets erroneously made.  In both cases, something will not work the way it is supposed to.

What is surprising in the Edinburgh finding is how common these DNA-RNA errors are and how ignorant we were that they were taking place.

Lead author, Dr. Andrew Jackson said:

“The most amazing thing is that by working to understand a rare genetic disease, we’ve uncovered the most common fault in DNA replication by far, which we didn’t even start out looking for!

More surprising still is that a single enzyme is so crucial to repairing over a million faults in the DNA of each cell, to protect the integrity of our entire genetic code.

“We expect our findings to have broad implications in the fields of autoimmunity and cancer in the future, but first we need to find out more about what effect the incorporation of RNA nucleotides is actually having on the genome.”

© 2012 Medical Research Council – Institute of Genetics and Molecular Medicine, Enzyme corrects more than one million faults in DNA replication, University of Edinburgh (via Phys.org) (10 May 2012) (paragraph split)

The moral? — In science, it is often impossible to predict what research is going to find — and that has implications for the budgeting process

At some level, the monetarily tight-fisted need to grudgingly accept that scientific progress requires the funding of “pure” research and even (sometimes) apparently useless projects.

For example, if Wikipedia is correct that only 50 cases of Aicardi-Goutières syndrome have been identified, budget-conscious institutions could certainly have argued that researching the syndrome should have been a very low (read “unfundable”) priority.

On the other hand, advocates could argue back that diseases with simple genetic correlations are exactly the ones that are most cost effective to pursue.  Their relative simplicity means that they are easier and, therefore, cheaper to untangle.  And the solution might have subsequently wider implications.

However, if the Edinburgh findings are accurate, it is unlikely that anyone would have predicted the breadth of applicability of this team’s result.

That is one of the joys of the scientific process.

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Published:
10 May 2012 – 15:25
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By BrainiYak
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Smallest fossil mammoth found on island of Crete helps to confirm the dwarfing effect of island isolation on large mammals — but the taxonomic reclassification of a dwarf Cretan elephant into a mammoth is likely to continue to be disputed

Citation

Victoria L. Herridge and Adrian M. Lister, Extreme insular dwarfism evolved in a mammoth, Proceedings of the Royal Society B [Biological Sciences], doi: 10.1098/rspb.2012.0671 (published online before print, 09 May 2012)

What is the evolutionary effect described as the “island rule”?

The authors explain the evolutionary effect of island confinement as having (i) a dwarfing effect on large mammals and (ii) an enlarging effect on small mammals.

The dwarfing effect appears to be due to the absence of competing large predators and an equally limited food supply.

Did the Cretan elephant dwarfs evolve from just one ancient elephant species, or were there mammoths there, too?

Originally, it had been assumed that dwarf Mediterranean island elephants had evolutionarily descended from the straight-tusked mainland elephant, Palaeoloxodon antiquus.

However, a 2006 DNA study controversially reclassified another local elephant species (Palaeoloxodon creticus) into being a mammoth (thereby becoming, Mammuthus creticus).

If true, this would create two dwarf Cretan lineages — one from elephants and the other from mammoths.

What the study did

The authors tried to clarify the dispute on taxonomic grounds.  They compared molars from the DNA-alleged mammoth to:

(a) the previously presumed source of Cretan elephants,

Palaeoloxodon antiquus (middle Pleistocene)

(b) as well as to three mammoth lineages:

Mammuthus rumanus (late Pliocene),

Mammuthus meridionalis (early Pleistocene — and supposedly the ancestor for Palaeoloxodon creticus),

Mammuthus trogontherii (middle Pleistocene — the same age as the elephant, P. antiquus).

Findings

According to the molar comparisons, the DNA-alleged mammoth is indeed a mammoth and evolved from either M. ramanus (late Pliocene) or M. meridionalis (early Pleistocene, and extinct in Europe between 800 and 700 years ago).

This means that the M. creticus may have arrived on Crete anywhere between 3.5 million years and 700,000 years ago.

Mammuthus creticus is similar in size to the smallest dwarf elephant species, P. falconeri, and smaller than all other known mammoth species.

Our taxonomic reassessment and morphological comparisons show that extreme insular dwarfism occurred in Mammuthus, not just in Palaeoloxodon, and that M. creticus is the smallest mammoth ever to have evolved.

© 2012 Victoria L. Herridge and Adrian M. Lister, Extreme insular dwarfism evolved in a mammoth, Proceedings of the Royal Society B [Biological Sciences], doi: 10.1098/rspb.2012.0671 (published online before print, 09 May 2012)

Caveat

I am suspicious of the replicability of studies that involve such limited materials (just a few molars) and, similarly, that educated guesses take into consideration the possibility that dwarfism (potentially) significantly alters the look of allegedly identical body structures.

I am also doubt the evolutionary reliability of purely morphological classifications.  I see no reason why different species could not evolve similar looking answers to fitness questions.  And I am not persuaded that we can reject the possibility that random mutations, statistical certain to be present in one or more of our samples, have not misled us into making possibly erroneous classifications.

BUT — this may simply be my ignorance talking.

The moral? — Maybe a weak study, but one whose findings seem (nevertheless) reasonable

This is a good example of a study in which we are dependent upon arcane and expert identifications of remnant materials.

Unlike biomedical research, where post-study statistical analyses and re-interpretations of the alleged data are possible, this fossil tooth study depends exclusively on the acuity of experts to distinguish teeth that probably look pretty much identical to everyone else.

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Published:
9 May 2012 – 08:41
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By BrainiYak
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A small neuroimaging study showed structural brain abnormalities in antisocial criminals with simultaneous psychopathy — but not in antisocial offenders without psychopathy

Citation

Sarah Gregory, Dominic ffytche, Andrew Simmons, Veena Kumari, Matthew Howard, Sheilagh Hodgins, and Nigel Blackwood, The Antisocial Brain: Psychopathy Matters, A Structural MRI Investigation of Antisocial Male Violent Offenders, Archives of General Psychiatry, doi:10.1001/archgenpsychiatry.2012.222 (early online publication, 07 May 2012)

Study’s objective

The investigators wanted to find out whether they could detect structural gray matter differences between two groups of violent criminals:

The first group of 17 men psychiatrically demonstrated a combination of antisocial personality disorder and psychopathy.

The second group of 27 men was also violently criminal, but it displayed only antisocial personality disorder.

A third group of 22 non-criminal, non-violent subjects served as a control group.

Method

The brain structures of these 66 subjects were calculated with a combination of magnetic resonance imaging (MRI) and Voxel-based morphometry.  The latter technique assesses brain structure by neuroimaging, essentially onto a statistically-derived template.

Results

The psychopathic group displayed reduced gray matter volumes in (i) the anterior rostral prefrontal cortex and (ii) both temporal poles — as compared to both other groups.  These areas have to do with executive function, impulse control, empathy, rule-following, and so on.

The reduced volumes of gray matter could not be attributed to substance abuse.

Note

 Severe alcoholism, for example, can result in reduced amounts of gray matter in the prefrontal cortex.  Alcoholics whose brains atrophy in this region simply reduce what comparatively little control over alcohol they had beforehand.

The violent, but purely antisocial subset exhibited gray matter structure and volumes similar those in the non-violent control group.

Why this small study’s finding about psychopaths may have implications

The team concluded that:

Reduced GM [gray matter] volume within areas implicated in empathic processing, moral reasoning, and processing of prosocial emotions such as guilt and embarrassment may contribute to the profound abnormalities of social behavior observed in psychopathy.

Evidence of robust structural brain differences between persistently violent men with and without psychopathy adds to the evidence that psychopathy represents a distinct phenotype.

© 2012 Sarah Gregory, Dominic ffytche, Andrew Simmons, Veena Kumari, Matthew Howard, Sheilagh Hodgins, and Nigel Blackwood, The Antisocial Brain: Psychopathy Matters, A Structural MRI Investigation of Antisocial Male Violent Offenders, Archives of General Psychiatry, doi:10.1001/archgenpsychiatry.2012.222 (early online publication, 07 May 2012) (at “Conclusions” in the abstract)

The moral? — Though freedom of will is an arguably necessary social construct for most of us, the concept may be misguided, when it comes to a small but significant subset of the population

If someone’s brain makes them violently uncontrollable, it is nonsensical to assume they have a significantly achievable chance at making more peaceful and socially integrative choices.

Brain findings of this kind have implications for an ethically defensible administration of criminal justice.

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Published:
7 May 2012 – 18:16
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By BrainiYak
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Supermoon (perigee-syzygy) — the media’s difficulty in providing decent explanations of this 412-day repeating phenomenon

Introduction — why bother with the media’s supermoon coverage?

My wife’s haziness about the details of the “supermoon” last night encouraged me to pay some attention to how the popular media had covered this ordinary happening.  (I wondered just how much my science background predisposed me to understanding something that other people would not.)

I discovered that obtaining a short explanation of the simple mechanics underlying the supermoon perception was more difficult than I had anticipated.  In other words, the media seemed to perplex-i-fy something reasonable simple.

Diagrams and details were almost universally lacking in the reports that I saw.  And no one that I could find, except Space.com, bothered to tell the public when the dim opposite of May 2012’s supermoon would take place.

The best explanations came from scientifically friendly sources: NASA, astronomer Steve Owens, and Wikipedia.

However, with those three sources so easily available, I was a little perplexed that the media had done such a scientifically uninformative job of explaining last night’s bright full moon.

Background — a diagram of moon stages

MoonConnection.com, Understanding the Moon Phases (2012)

What is a supermoon?

The “supermoon” — more accurately called a “perigee-syzygy” moon — occurs approximately once every 412 days, as the full moon stage coincides with its closest approach to earth (perigee).

Weather equal, the full moon looks larger and, therefore, brighter than normal at this point.

Naturally, the brightest of perigee moons occur when the full moon stage coincides almost exactly with the lunar orbit’s point of perigee.  NASA calls these “super perigee moons.”

NASA’s supermoon explanation

From Tony Phillips:

The scientific term for the phenomenon is “perigee moon.”

Full Moons vary in size because of the oval shape of the Moon’s orbit. The Moon follows an elliptical path around Earth with one side (“perigee”) about 50,000 km closer than the other (“apogee”). Full Moons that occur on the perigee side of the Moon’s orbit seem extra big and bright.

Such is the case on May 5th at 11:34 pm Eastern Daylight Time1 when the Moon reaches perigee.

Super perigee Moons are actually fairly common.  The Moon becomes full within a few hours of its closest approach to Earth about once a year on average.   The last such coincidence occurred on March 19th, 2011, producing a full Moon that was almost 400 km closer than this one.

© 2012 Tony Phillips, Perigee “Super Moon” On May 5-6, NASA (02 May 2012) (paragraph split)

NASA went on to explain that perigee moons do raise the encroachment of tides, but only by a few centimeters.  Even when geography assists, the water rise is only about 15 centimeters (6 inches).  Hardly something to become alarmed about.

NASA’s visualization — a video

Science Casts – ScienceAtNASA, The Super Moon of May 2012, NASA (09 March 2012) (including diagrams of the moon’s orbit around the earth and an animated overlap of perceived moon size differences)

And Marco Langbroek’s excellent juxtaposition of still photographs

Marco Langbroek, Supermoon comparison, Wikipedia (19 March 2011) (top right photo, title and author evident after clicking on it, showing supermoon of 19 March 2011, as compared to the “average” moon of 20 December 2012)

Space.com’s contribution to understanding the connection of orbital periodicity to full moon brightness

Anticipating a precocious child’s question:

This month’s [May] full moon is due to be about 16 percent brighter than average.

In contrast, later this year on Nov. 28, the full moon will coincide with apogee, the moon’s farthest approach, offering a particularly small and dim full moon.

© 2012 Staff, ‘Supermoon’ Alert: Biggest Full Moon of 2012 Occurs This Week, Space.com (30 April 2012)

How much perigee-ness is required for a supermoon?

Absent specialized equipment and technique, it is not really possible to perceptually discern differences in size and brightness between full moons occurring at (a) absolute perigee or (b) just-before or just-after pergiee.

Perigee-syzygy — why is that term more informative than “supermoon”?

“Supermoon” certainly has a sensationalizing popular twang, but it says nothing about the mechanical causation of the phenomenon.

The term, syzygy, refers to state where a gravitational system’s astronomical objects have “fallen” into a straight line.  Therefore, the sun-earth-moon system achieves syzygy at our earth-bound perception of new and full moon stages.

When we combine perigee and syzygy, we recognize that we have specified the alignment that causes our perception of the “supermoon” phenomenon.   The scientific term, consequently, is much more phenomenologically descriptive than the popular one.

The best easily discovered explanation of perigee-syzygy timing — comes from astronomer Steve Owens

Astronomer and science communicator, Steve Owens (at Dark Sky Diary) calculated when perigee moons best correspond with syzygy:

[T]he Moon is full every 29.530 days.

The Moon’s orbit is elliptical . . . and so you would expect a perigee once every 27.321 days.

However the elliptical path around which the Moon orbits the Earth precesses (that is it is not fixed with the perigee occuring at the same part of each orbit; the place where perigee occurs moves, or pressesses) with a period of 8.8504 years, so that perigee doesn’t occur once every 27.321 days but rather once every 27.554 days (called the anomalistic period).

[Y]ou find that a full Moon will occur at perigee once every 411.776 days . . . or just less than once per year.

 All the articles that cite this as the closest full Moon in 18.6 years are wrong; there was a full Moon at perigee 411.784 days ago, on Feb 28th 2010 when the full Moon occurred at 1700 UT [universal time] and perigee occurred just 19 hours before at 2200 UT on Feb 27th 2010.

 The next so-called Supermoon will occur on May 6th 2012, when the full Moon will occur at 0400 UT, with perigee at the same time.

© 2012 Steve Owens, Supermoon Nonsense, Dark Sky Diary (09 March 2012)

The moral? — Our media often misses opportunities to better educate us about science

That is particularly distressing because easily witnessed natural phenomena present such effective opportunities to begin advancing the public’s scientific literacy.

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Published:
6 May 2012 – 11:48
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By BrainiYak
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Science article about dam building on the Yangtze/Jinsha River surveys evidence for increased earthquake risk

Citation

Jane Qiu, Trouble on the Yangtze, Science 336(6079): 288-291 (20 April 2012)

China’s emphasis on hydropower

The Chinese government has set a goal of achieving 15 percent non-fossil energy production by 2020.  Author Jane Qiu says that most of this will come from hydropower.  And much of that from what the Chinese call the Jinsha River.

Three dams are already under construction and five more are planned:

At a combined height of 2 kilometers, the dams will convert the rapidly flowing Jinsha River into a series of stepped lakes with few free-flowing sections,” says Liao Wngeng . . .

Also tagged for development are . . . tributaries such as the Yalong, Min, and Dahu rivers.

© 2012 Jane Qiu, Trouble on the Yangtze, Science 336(6079): 288-291 (20 April 2012) (at pages 288-289)

And the enhanced risk for severe earthquakes in geologically active regions

Among the obvious threats to river fish and habitat is the risk for earthquakes.  Much of the planned reservoir route is underlain by active faults.

Ordinarily one might shrug, but in this case computer modeling evidence seems to exist that the 7.9 magnitude Wenchuan quake that killed 80,000 people in 2008 was caused, hastened, or aggravated by water behind the Zipingpu Dam.

According to writer Jane Qiu, most involved Chinese scientists agree that the quake’s epicenter lay directly under the reservoir.  They disagree about its depth, and therefore the ability of the water itself, or its weight, to affect the fault zone:

Despite the controversies, many Chinese geophysicists now agree that the reservoir may be connected to the Wenchuan earthquake.

Even if the hypocenter [the depth of the first rupture] lies 19 kilometers below the surface, Liu says, as his calculation shows, this doesn’t exclude the possibility that Zipingpu hastened the quake because “small incremental stress changes due to the reservoir could rupture critically stressed faults—even without water reaching them.”

Jane Qiu, Evidence Mounts for Dam-Quake Link, Science 336(6079): 291 (20 April 2012) (paragraph split) (at page 291)

If there really is a connection, this is not a risk that most sensible people would ignore.  Even in authoritarian China, 80,000 dead is not a trivial event.

China’s plutocrats and government agencies operate pretty much like ours

Critics of China’s dam building are upset by the government’s willingness to ignore threats to the environment.

As in the United States (think of the Deepwater Horizon oil spill), government agencies are heavily influenced by the people who benefit from the projects that are ostensibly being regulated:

By law, dams cannot be constructed in nature reserves or their buffer zones. But the government is all too willing to redraw the boundaries to accommodate hydropower projects, some say. The Xiaonanhai Dam in particular, Guo says, is “yet another example of the country’s disregard for the environment.”

Critics say EIA [environmental impact assessment] committee members are often paid for their services by dam projects and deliver favorable assessments in order to be invited back.

“The EIA is just about friends evaluating each other’s projects,” says Wang Mingna, a hydrologist at the Chinese Institute of Water Resources and Hydropower Research in Beijing.

Scientists’ warnings “often fall on deaf ears,” adds ecologist Yang Junxing of CAS’s Kunming Institute of Zoology.

© 2012 Jane Qiu, Trouble on the Yangtze, Science 336(6079): 288-291 (20 April 2012) (at page 291)

The moral? — Dam building may have effects beyond the obvious and plutocrats respond to these the way they do everything else

The first is scientifically interesting and the second disheartening.

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Published:
4 May 2012 – 18:16
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By BrainiYak
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University of California-Berkeley researchers are going to core roughly 130,000 years of sediments in Clear Lake to investigate patterns of climate change in the region — and a parable about cumulative science

Citation

Robert Sanders, Scientists core into Clear Lake to explore past climate change, University of California-Berkeley News Center (03 May 2012)

Where Clear Lake is and why it is unique

Clear Lake sits on a more or less West to East line that connects Ukiah and Yuba City California.

It is the largest freshwater lake entirely within California and is relatively unique in having escaped the Ice Age glacial scouring.  Water depths reportedly vary from 8.2 to 18.3 meters (27 to 60 feet).

The United States Geological Survey previously cored the lake bottom in 1973 and 1980.  A sample taken from near the proposed Berkeley drilling site went back 130,000 years, and other lake sediments go back 500,000 years.  The USGS only sampled their cores at 1 meter intervals, which was not precise enough for the Berkeley teams’ current climate mapping purpose.

The scientific goal

The idea is to collect precise data regarding past climate change and its effects on the biosphere, so as to improve today’s climate change computer modeling in this California region.

How the coring project will work

According to Robert Sanders, Berkeley hired a non-profit drilling team — DOSECC, which stands for “Drilling, Observation and Sampling of the Earths Continental Crust” — to get two 120 meter (roughly 395 feet) cores.

Each will be 8 centimeters (3 inches) in diameter.  The cores will be split into 3-meter-long segments.

The cores will be cold-stored at the University of Minnesota’s National Lacustrine Core Facility (“LaCore”), where Looy’s team can split each longitudinally.  The team will leave one of the halves in storage and bring the other back to Berkeley for examination.

At Berkeley, the team will dissect and date 1 centimeter intervals along their halves, looking for pollen and other signs of plant and animal communities.  Presumably they will use previously established bio and geomarkers to calculate temperature, oxygen and nutrient levels, as well as to estimate past rainfall amounts and lake water levels.

One key idea is to look for a period in the past that approximates the warming rate we are experiencing today

Professor Looy told Robert Sanders:

“Rates of global warming almost as fast as what we see today last happened during the shift from the last glacial to the current interglacial roughly 12,000 years ago, so that is one time interval we will focus on.”

© 2012 Robert Sanders, Scientists core into Clear Lake to explore past climate change, University of California-Berkeley News Center (03 May 2012)

A subtle moral — Science stands on our predecessors’ shoulders

One prominent theme in science is that investigation is cumulative.  We stand on our antecedents’ shoulders.

Here, Professor Looy credited the USGS with work well done.  Their 1973 and 1980 investigations gave today’s Berkeley team valuable information regarding where in the coming lake cores they will need to focus.

On a human note, it is highly unlikely that the USGS teams could foresee what their sediment cores would be used to investigate decades afterward.  Their effort preceded most of the world’s concern about rapid climate change.  I would bet that most of these scientists are now retired.

Science builds on itself.  That’s why it is important to build each step properly.  And why it is perspective-granting to acknowledge other people’s contributions.

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Published:
3 May 2012 – 18:20
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By BrainiYak
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