Wasp vs. ant

If there’s anything creepier than insects that lay their eggs inside other insects so their larvae can feast on the living flesh of their prey, I’m not sure what it is.  For your Halloween viewing pleasure, José-María Gómez Durán and Cornelis van Achterberg of NCB Naturalis Leiden have managed to film and describe four species of parasitoid wasps in the act of depositing their eggs in ants.  Two of the wasp species are new to science.

As you can see in the video below, the wasps use the strategy of attacking from above and behind the ants.  This technique is highly affective, resulting in an 80% success rate in depositing eggs.  Don’t be fooled by the slow motion in the video.  The entire sequence from landing on an ant to taking off again lasts less than three quarters of a second.

If that wasn’t enough for you, check out videos two, three and four.

By the way, parasitoids differ from other types of parasites in that they always kill their victims.  In other words, the hapless ants in the video are doomed to an extremely unpleasant death.

Amorphous diamond?

Yu Lin and Wendy Mao of Stanford University have succeeded in making what they call ‘an amorphous diamond’.  You may be wondering, as I was, what an amorphous diamond is and why it isn’t a non sequitur.

As you may already know, in addition to being the hardest naturally occurring material, diamonds are a crystalline, or highly ordered, form of pure carbon.  In contrast, amorphous substances have no repeating patterns.  They are by definition non-crystalline. It already doesn’t look good for ‘amorphous diamonds’.

To make their new material, the researchers took tiny beads of amorphous carbon and smashed them with over 400,000 atmospheres of pressure.  As a result, the bonds within the carbon beads shifted, making the resulting material as hard as diamonds (based on further pressure tests).  Yet, the beads did not become crystalline but stayed amorphous. 

The ‘amorphous diamond’ could turn out to be a very useful product.  Like oobleck, it’s only hard under extreme pressure. Once the pressure is released, the material returns to a softer state.  This means that the material may be tunable, responding to the amount of hardness required.  Not a bad feature in a structural component.

That said, in my opinion, ‘amorphous diamond’ is a non sequitur.  I think the authors are using the name ‘diamond’ as shorthand for ‘substance that is harder than anything else on Earth—I mean, this thing is really hard!  You won’t believe how hard it is!’.

Just for Fun: Quantum levitation

Check out this amazing demonstration of a quantum superconductor locked in a magnetic field, presented by Tel-Aviv University at the 2011 Association of Science-Technology Centers Annual Conference.







Wonder how that works?  Here's the explanation.





Hat tip:  Pharyngula.

More than one blow to knock Uranus over

Alessandro Morbidelli from the Observatoire de la Cote d’Azur, Nice led an international team of cosmologists in answering a longstanding question:  How did Uranus get its tilt?  Computer simulations indicate that it took at least two thumps from planet-sized bodies.

Uranus is unusual in that its rotational axis is almost perpendicular to the plane of its orbit around the sun.  In other words, it’s spinning on its side.  Other planets have some degree of tilt, the Earth is tilted by 23 degrees (which accounts for our seasons), but none come close to the 98 degree tilt of Uranus.

Until recently, astronomers thought that a single collision with an object larger than the Earth knocked Uranus onto its side.  However, in that scenario, Uranus’s moons should have remained in the horizontal plane (orbiting around Uranus pole to pole).  Instead, they apparently flipped over when Uranus did and now orbit in the plane of Uranus’s equator.  A single collision could not account for rotating the entire Uranus plus moons system.  In contrast, two or more smaller collisions occurring before the moons were fully formed could have resulted in the system we see today.

The evolution of flight, as performed by robots

How did birds develop flight?  There are two competing theories about this.  First, that birds ran along the ground until, by flapping their progressively more powerful wings, they could finally take off.  Second, that birds glided down from tree branches or other heights, extending their range by flapping their wings.  In each case, smaller less powerful wings would give some advantage even if they didn’t convey actual flight.  So which scenario was more likely?  According to research done by Ron Fearing and his Berkeley students, the second narrative may be the more apt.  And you may be surprised to learn that they draw this conclusion from studying robots.

Fearing and his team added motorized flapping wings to a small six legged robot called DASH (Dynamic Autonomous Sprawled Hexapod).  The original DASH, developed in 2009, was having some problems negotiating inclines and other obstacles.  DASH+Wings was not only more stable and agile, but also much quicker, nearly doubling in speed. You can watch some of the tests below, slowed to 1/10th speed.

What does this have to do with the evolution of flight?  Even with the impressive doubling of ground speed the robot was not able to get air born.  In fact, computer models suggest that to achieve liftoff, an animal would have to triple its running speed.  If DASH+Wings is a reasonable model of a running animal, this data implies that flight could not have developed from the ground up.  That’s a big if though.  Obviously, this question is not settled yet.  However, it’s interesting to think that the question of how flight evolved might one day be resolved by watching robots.

Easy wake alarm

When I was a kid, my brother and I played a board game called ‘The Inventors’ which featured an ‘E-Z wake alarm’.  This alarm system was essentially a rope tied to a payload precariously placed above the sleeper’s head.  Jemina Sylvia from the Jerusalem College of Engineering led a team in developing a gentler way to wake people up.  They link their alarm clock to the slumberer’s electroencephalography (EEG) waves so that he or she can be awoken during the least jarring part of the sleep cycle.

As people doze, they alternate between rapid eye movement or REM sleep, the stage at which most dreaming occurs, and non-REM sleep.  There are four stages of non-REM sleep, each progressively deeper than the previous stage. The various sleep stages can be distinguished by EEG waves.  As you can see in the hypnogram below, most people follow 90 minute patterns of REM through stage 4, then REM again.

In this study, volunteers were hooked up to EEG monitors as they slept, and the output was sent to their alarm clocks, which were programmed not to awaken them if they were in stage 3 or 4.  Instead, the clock waited until the sleeper was in one of the lighter sleep stages before sounding.

As of now, the device has some drawbacks, not least of which is that the sleeper has to wear scalp electrodes that are wired to a clock—not exactly what the person seeking a more pleasant sleep experience is looking for.  However, the researchers expect that a headband containing wireless electrodes could do the trick.  And of course, there’s the question of whether people will be late for appointments if their clocks wait for a more convenient time to wake them.

Is your roof a good candidate for solar panels?

Thanks to researchers from the University of Gothenburg, there’s a new tool for assessing which roofs would make the best locations for solar panels.  The tool, named Solar Energy from Existing Structures (SEES) determines the amount of sunlight each section of a roof can expect to get throughout the year.

Even in a sunny climate, not all roofs are equal when it comes to collecting solar power.  Trees, other buildings and geographical barriers can affect the amount of sunlight that falls on a section of roof.  The Swedish scientists developed SEES to determine not only whether a particular roof was suitable, but also how to orient solar panels on the selected roofs. 

The scientists use data from geographical information systems to precisely recreate three-dimensional environments, including local landscapes and structures.  They then illuminated their models to simulate different times of day and seasons.  As you can see below, this provides a map of solar efficiency.

Caption: The new SEES tool provides a map of the solar efficiency of individual roofs, based on their surroundings. Warmer colors show where the solar irradiance is highest. The figure shows the old Härlanda jail and its surroundings.

Credit: University of Gothenburg.

So far, SEES has only been used in a pilot program within Gothenburg.  However, the researchers see no reason why the system can’t be adapted for use everywhere.

Bad news for mobile phone users—you don’t want to know

One sixth of the mobile phones tested in Britain are contaminated with fecal bacteria.  This cheery news was presented by scientists from the University of London to commemorate Global Handwashing Day, which was celebrated on October 15^th. 

Overall, 92% of the 390 mobile phones tested had some bacteria on them and 16% were contaminated with E. coli, an intestinal species of bacteria.  Unless people are dipping their phones in raw hamburger, there’s only one place E. coli can come from.  Meanwhile, 95% of people insist that they do wash with soap after visiting the loo.  Clearly, the evidence is against them.

Apart from handling your phone with tongs, what can you do to remedy this situation?  There are ways to clean mobile phones.  You can wipe down most phones with microfiber cloths dampened with alcohol, but check the instruction manual of your own phone first.  And obviously, make sure you wash thoroughly with soap and water after each trip to the toilet.

Good news for mobile phone users—no sign of cancer

A large Danish study finds no increased cancer rates even among people with frequent and long-term mobile phone use.  This isn’t surprising, considering that there is no known mechanism for how the electromagnetic radiation given off by mobile phones could affect either DNA or cells.  Still, it’s good to hear.

The researchers, led by Patrizia Frei of the Danish Cancer Society conducted the largest study of mobile phone users to date.  Thanks to the Danish system of registering all residents, the entire Danish population could be divided into those that do or do not have mobile phone subscriptions.  Starting in 1987, the year mobile handsets arrived in Denmark, phone usage was mapped with socioeconomic status and cancer rates for over 350,000 people.

So what were the results?  Rates of central nervous system cancers (glioma, meningioma) did not increase with increased mobile phone usage. In fact, some types of cancer actually decreased, though the authors suggest that this may have been due to lower rates of smoking amongst early adopters of mobile phones.

As I mentioned, this is not at all surprising.  A mobile phone puts out less than two watts of non-ionizing radiation.  In comparison, your typical microwave requires at least 500 watts to cook your food.  And even if mobile phones did put out a significant amount of radiation, which they don’t, non-ionizing radiation is not known to cause genetic mutations of any kind.  At best, it increases temperature.  How the meager radiation coming from a cell phone could heat one’s brain on the far side of one’s skull enough to affect brain cells has never been explained.  Probably because it can’t and doesn’t.

Just for fun: Slinky Drop

Ever wonder what happens when you drop a stretched out slinky?  Check out these videos to find out.





Got your answer?







Got your prediction?





Hat tip:  Not Exactly Rocket Science.

Writing Braille on an ordinary tablet

Wouldn’t it be great if blind people could jot down notes on their tablet computers without needing elaborate and expensive Braille writing devices?  Thanks to the innovations of a team composed of undergraduate Adam Duran and his mentors Adrian Lew and Sohan Dharmaraja, that may soon be possible.  The team participated in the Army High-Performance Computing Research Center’s summer challenge at Stanford University. 

The original challenge was to use the camera on mobile devices to create Braille readers, but Duran and his mentors decided to make a Braille writer instead. Braille consists of arrangements of raised dots corresponding to letters, numbers, punctuation, and even chemical and mathematical symbols.  Currently, people who wish to write in Braille can modify their laptops with writers that can cost up to $6000.  They can also use dedicated Braille writers (also costing thousands of dollars) that resemble typewriters except for having only eight keys:  six for placing dots and two for carriage return and delete.  Duran’s team set out to replicate the eight-character Braille writer on an ordinary tablet.

Left:  Braille writer attached to laptop.  Photo by Podzemnik, 2/9/2011.

Right:  Stand alone Braille writer. Photo by Matthieu Faure, 10/15/2008.

The obvious challenge was to figure out how a blind person could know where to place his fingers on the smooth panel of a tablet in order to hit the right keys.  That turned out to be no problem at all, thanks to some ingenious software.  The user simply places his eight fingertips on the panel, and the keys automatically orient themselves to those points.  You can see a demonstration below.

Needless to say, this device would be immensely useful.  Blind people could not only take notes during classes or meetings, but by wearing the tablet around their necks, they could also jot down information such as names and phone numbers as they walk along.  The system isn’t yet available for public consumption, but hopefully will be soon.

Worms inherit the Earth

At least, worms may have been among the first animals to recolonize the planet after the Cretaceous-Tertiary (K-T) extinction event.  Karen Chin and her team from the University of Colorado at Boulder have discovered evidence of worm burrows that may have been made within a few thousand years of the asteroid strike that devastated life on Earth 65 million years ago.  The results were presented at the 2011 annual meeting of the Geological Society of America.

Chin and her team found the burrows traveling horizontally through the sediment just inches above the K-T boundary layer.  This provided strong evidence that worms were present in abundance, despite the lack of fossilized tissue.  As much of the plant life on Earth would have been obliterated by the nuclear winter caused by the asteroid crash, some researchers speculate that many surviving animals subsisted on decomposing organic materials rather than on living plants and animals.  This may have been an ideal substrate for worms, which in turn would have been welcome fair for other animals.

By the way, geologists now frown on using the term ‘Tertiary’ for this boundary.  For that reason, you may see this event abbreviated as ‘K-Pg’ for ‘Cretaceous-Paleogene’.  As to why Cretaceous is abbreviated with a ‘K’, you can thank the Germans for calling that time period ‘Kreidezeit’ after the word ‘kreide’ meaning ‘chalk’.

Zeroing in on the genetic causes of autism

Two groups have created new mouse models of autism spectrum disorder (ASD) diseases by adding or subtracting specific genes or chromosome regions. 

ASD clearly has a very strong genetic component.  Several genes and groups of genes have been implicated in the development of autism, both by identifying genetic changes in people and by replicating those changes in mice.  In particular, copy number (the number of times the same gene is repeated throughout the genome) of some genes seems to be critical for proper brain development.

Researchers from Cold Spring Harbor Laboratory, Stanford, Wharton University and the Hospital for Sick Children, Toronto have been studying a region of chromosome 16 that is often deleted in humans with ASD.  They bred mice with comparable deletions and found that the mice exhibited many behaviors consistent with autism.

Another group from Harvard increased the copy number of a gene (Ube3a) found on chromosome 15.  People with more than the usual number of Ube3a genes display symptoms of ASD.  Mice bred with triple the dosage of this gene exhibited autistic traits, such as repetitive behavior.

Clearly, there is no single cause of ASD. Many genes have been implicated in this disorder, including genes on chromosomes 15, 16 and X.  However, as we study mouse models for the disease, we may be closer to finding treatments.

Bilingualism staves off Alzheimer’s symptoms

University of Toronto researchers led by Tom Schweizer have found that Alzheimer’s disease (AD) has to progress twice as far in bilingual patients as in monolingual people before symptoms become apparent.  In other words, multilingual people can sustain much more brain damage before they become noticeably symptomatic.

The researchers ran CT scans of matched patients who had been diagnosed with probable AD.  Half the patients were fluent in two languages, the other half spoke only one language.  Although both groups performed equally well in all cognitive tests, the bilingual subjects displayed twice as much brain atrophy as the monolingual subjects.  This data corroborates previous observations that bilingual patients develop AD up to five years later than their monolingual cohorts. 

It’s not yet established whether there’s something specific about language or if it’s simply the act of using our brains (and alternating smoothly between two languages in both thought and speech does require an enormous amount of computing power) that is so protective.  If speaking two languages is critical, it may not be necessary to have spoken both languages from early childhood.  

To be clear, whatever mechanism is at work merely postpones the diagnosis of AD, it doesn't cure or prevent the disease.  Still, five extra years of being one's self is nothing to scoff at.

Food allergies begone

Food allergies affect millions of Americans, some so severely that the merest trace of the offending food can be lethal.  Sufferers have to watch not only everything they eat, but everything people around them are eating as well.  The need for that type of hyper-vigilance may be at thing of the past.  Northwestern researchers led by Stephen Miller and Paul Bryce may have found a way to circumvent the immune response to normally harmless food items.

The researchers attached peanut allergens to mouse leukocytes (white blood cells) and injected the cells into mice that had been bred to have life-threatening peanut allergies.  Once attached to the mouse blood cells, the immune systems of the mice accepted the peanut proteins as benign.  Later, when these same mice were fed peanut extracts, they did not go into anaphylactic shock like their untreated cohorts. A second test attaching egg-white protein to leukocytes was equally successful. 

Food allergies aren’t the only illnesses caused by overly enthusiastic immune systems. Miller and his team have previously used this technique to halt the progression of autoimmune diseases such as type 1 diabetes, though only in animal models thus far.  They suggest that this method can also be used to treat multiple allergies at once.

Good news/bad news about coral reefs

First, the bad news.  Thanks to climate change, coral reefs around the world are in trouble.  Increased carbon dioxide is making the oceans more acidic, which interferes with the corals’ ability to build their exoskeletons.  In addition, the warmer temperatures themselves result in ‘coral bleaching’ or the loss of symbiotic algae from within the coral bodies.  As corals get most of their nutrients from the photosynthetic efforts of these algae, bleached corals do not survive for long. 

Many experts predict that coral reefs, which support a quarter of all marine life, will go extinct unless we can drastically reduce carbon levels.   In other words, it won’t be enough to immediately reduce emissions.  To protect corals, we would need to actively suck carbon dioxide out of the atmosphere. 

Now a bit of good news.  Researchers led by Arnaud Brayard of the Université de Bourgogne have found that coral colonies can recover much more quickly than previously thought.  During the Permian/Triassic extinction event of 252 million years ago, 90% of all species went extinct, including many types of coral.  Previously, paleontologists assumed that it took about five million years for coral reefs to recover, but new evidence suggests that it only took…wait for it… about 1.5 million years.

Okay, that’s not really all that good.  Still, it does give some hope for the distant future.  And if we can cut emissions now, we may be able to avoid having to wait 1.5 million years for corals to recover.

Just for fun: Beautiful proteins

Mike Tyka works on protein folding at the University of Washington.  In his blog Beautiful Proteins, he collects examples of 'aesthetically pleasing' protein folds, and provides full descriptions.  Here's one example:


Molybdenum cofactor biosynthesis protein MoaC.

Hat tip:  Not Exactly Rocket Science.

Fish use tools

The list of animals that use tools, an ability once thought to be the sole province of human beings, is steadily expanding.  First great apes, then other primates, mammals, birds, and now fish have been found manipulating their environments for specific purposes.  Here, Giacomo Bernardi of the University of California Santa Cruz documents an example of a fish using an anvil.

The orange-dotted tuskfish (Choerodon anchorago) shown in the video is a member of a very large family of marine fishes known as wrasse.  The fish first collects a specimen by fanning sand away from it and then searches for a suitable rock on which to smash it.  As you can see in the clip, this takes quite a bit of searching and several attempts.  Although it's usually a mistake to anthropomorphize animals, this fish certainly looks like it has a clear intent.

Interestingly, three other species of wrasse have been observed (but not documented) engaging in the same behavior.  Because the family of wrasse is so large and diverse, these four species are not closely related to one another evolutionarily.  This suggests that all wrasse may be capable of using anvils in this manner, or even that other types of fish are as well.

Where did Earth’s water come from?

It is commonly accepted that soon after formation, the Earth was a dry planet.  The water that now makes up about 70% of its surface came later via collisions with water-bearing space objects.  Those objects were thought to be have almost exclusively been asteroids, but new research suggests that some of them may have been comets.

It’s no surprise that comets contain vast amounts of water.  They are, after all, mainly dirty snowballs of ice, gases and organic compounds.  However, upon closer examination, the amount of heavy hydrogen (deuterium) present on some comets has not matched the ratio found in our oceans, indicating that those comets could not have made significant contributions to our oceans.

More recently, an international team of astronomers examined the comet Hartley 2 and found that its deuterium/hydrogen ratio does match that of Earth’s oceans.  Hartley 2 may have little in common with the previously studied comets, having most likely come from the Kuiper belt and not the Oort cloud like the rest of the comets. 

While there’s no doubt that much of our water was delivered via asteroid, this data suggests some of it may have come from comets as well.

Image of Hartley 2 comet.

How fish move on land

Movement across land requires significant evolutionary changes compared to movement through a liquid medium.  Or so biologists thought.  Alice Gibb of Northern Arizona University and her colleagues from that school, Wake Forest Universtiy and Vassar College have found that some fully aquatic fish can move across terrestrial environments quite successfully with no obvious modifications of body plan at all.  In fact, they use some of the same strategies to escape predators on land as they do in the water.

For their studies, the researchers used killifishes, a group of teleost fish similar to guppies, that tend to live at the water’s edge.  Killifishes often find themselves temporarily stranded on land, either intentionally or by accident.  Once there, they employ the same technique that gives them a fast start escape in the water, namely a tail flip.  In the water, a rapid snap of the tail gives the fish a burst of speed whereas on land it causes the fish to spring several body lengths away.

The significance of this finding is that it suggests that many more types of aquatic organisms may have made forays onto the land than previously thought.

You can see some video clips of the leaping fish here.  No fish were harmed during the making of these videos.

Smell templates in the brain

According to new research by Christina Zelano and Jay Gottfried of Northwestern University and Aprajita Mohanty of Stony Brook University, our brains may be pre-wired to recognize specific scents.  As we anticipate smelling something, be it a rose or a rotten fish, our brains prepare to compare that odor to a preexisting template.  Once the odor actually hits our nostrils, there’s a strong and immediate match.

The researchers tested this assertion by giving subjects distinctive odors (watermelon and/or Playdoh) while they were in an MRI machine.  The volunteers were first primed to identify one of these two smells, and then given a countdown before the smell was administered. The subjects were told to press a button when they identified the target scent, if present.  If the target smell matched the expectation (they were told to prepare for a watermelon scent and watermelon smell was indeed presented), pre-smell and post-smell scans of the olfactory center of the brain showed greater correlation.  In other words, the subjects’ brains were primed to receive a specific odor.

What could be the advantage of having these ready-to-go scent templates?  The scientists suggest that predictive scent templates can reduce processing time.  They may also allow us to identify smells in smaller concentrations.  Zelano gives the example of being able to quickly determine whether milk is spoiled.

You can see an explanation below:

Sniffing Out the Brain's Predictive Power from Northwestern News on Vimeo.

This study raises some interesting questions that I hope will be addressed.  For one thing, just how many of these templates do we have, and how permanent are they?  Presumably, all the test subjects were already familiar with the scents of watermelon and of Playdoh.  What if they’d been presented with something completely foreign to them?  Or what if the subjects hadn’t known ahead of time what to expect?

Transposons gave us pregnancy

Placental mammals nurture their embryos within their uteri.  This gives the offspring extra protection compared to animals that leave their eggs in nests.  But how did this reproductive strategy arise in the first place?  According to Yale University researchers led by Vincent Lynch, we can thank transposable elements for the ability to sustain a pregnancy.

A transposon is a snippet of DNA that can insert itself into the longer DNA sequence that makes up an organism’s genome.  Once inserted, the cell’s DNA replication machinery can’t distinguish the transposon from any other part of the genome.  Consequently, it gets copied and passed on to all subsequent daughter cells.  Often the insertion is completely benign, but once in a while it either disrupts something important, or, as in this case, adds something important.

The researchers found that a group of transposable elements called MER20 were responsible for controlling the gene expression of more than an eighth of the genes involved in endometrial expression in placental mammals.  In other words, once these transposons inserted into the DNA of some distant mammalian ancestor over 100 million years ago, they went about reorganizing the function of the endometrial cells so that the creatures could now maintain a prolonged pregnancy.  Mammals without the coordinating efforts of MER20 can remain pregnant for only a fraction of the time their embryos require to fully develop.  We know these animals as ‘marsupials’. 

So, if you’re in the mood to thank your mother for giving you life, you can also thank her MER20 transposons for not requiring you to hatch out of an egg or a pouch.

And your 2011 Nobel Prize winners are….

Each year on December 10^th, the Nobel Prize Committee awards prizes for achievement in a variety of fields.  The day commemorates the death of Alfred Nobel, the Swedish inventor of dynamite.  This year, five prizes will be awarded, and the following people will be heading to Stockholm to be honored:

In physics, the prize is going to Americans Saul Perlmutter and Adam Reiss, and to Australian Brian Schimidt.  Ever hear of dark matter dark energy?  You can thank these guys.  They proved that the universe is not only expanding, but that this expansion is accelerating in a way that can’t be accounted for with known factors like regular matter and energy.

The chemistry prize goes to Israeli Daniel Schectman for his discovery of quasicrystals.  Crystals have regularly repeating patterns.  Quasicrystals have patterns too, but they don’t repeat.  This could have implications in material science.

The Nobel for medicine was split three ways by researchers who had jointly worked out how key components of our immune systems work.  The prize went to Jules Hoffmann, born in Luxembourg but living in France, and Bruce Beutler, born in the U.S. and living in the U.S. and Ralph Steinman, born in Canada but not currently living.  Normally, the Nobel cannot be given posthumously, however, because the committee selected Steinman before hearing of his death, his estate will receive the prize.

There is also a literature prize that went to Swedish poet Tomas Trantromer.

Finally, the peace prize that was shared by three women who led non-violent campaigns to advance women’s rights and world peace:  Liberian President Ellen Johnson Sirleaf, Leymah Gbowee, also from Liberia, and Tawakkul Karman from Yemen.

Hat tip:  Skeptics’ Guide to the Universe.

Just for fun: Quirkology

Richard Wiseman, a psychologist from the University of Hertfordshire, may be best known for his books and videos about illusion and self-deception, and what he calls ‘Quirkology’.

Here are a couple of samples.

Use fullscreen for this one:

To find an assortment of science tricks to amaze your friends, check out his books or YouTube page.

Redefining standard units

An international team of researchers is in the process of redefining two international standard units to be more in line with the constants of nature.  If the rest of the scientific community accepts their results, we may have new standards for the measurement of mass and of electrical current.

The Système Internationale d'unités (SI) includes seven definitions of measurement that are used to calibrate everything else.  However, some of those definitions rely on factors are not as immutable as we might hope.  For example, mass is measured in kilograms, which are currently defined as the mass of a specific block of platinum-iridium alloy.  That means that everything in the universe weighs some number of these nuggets of alloy.  What if the ‘International Prototype Kilogram’ got damaged?  Much better to have that measurement defined by an unchanging constant. 

To that end, scientists led by T.J.B.M. Janssen of the National Physical Laboratory at Teddington are studying the quantum Hall effect in graphene.  This effect relates electrical resistance to the Planck constant and to the electron charge.  If the quantum Hall effect turns out to be universal, it will allow researchers to redefine the kilogram in terms of the Planck constant and amperes (measurements of current) in terms of electron charge.

You can watch Janssen’s description below.

By the way, the other SI units are the meter for distance, the second for time, the Kelvin for temperature, the candela for brightness and the mole for amount.

Florida has the most invasive reptiles

Invasive species are a problem in many regions of the world.  Just ask the Australians what they think of the rabbit or the cane toad.  However, according to a new study, the world record for introduced reptiles belongs to the state of Florida.

Invasive species are species that have been introduced into a new ecosystem, often inadvertently by human activity.  For example, a deadly tree parasite known as the emerald ash borer spreads from region to region in firewood.  Alternatively, some species are released on purpose when people grow tired of their exotic pets and dump them outside.  This is the leading cause for Florida’s invasive reptile community.  Thanks to irresponsible pet buyers, there are now more than three times as many non-native reptile species thriving in Florida as native ones.

There are no easy solutions to this problem.  Pubic awareness may decrease the number of non-native species deliberately released into an area, but short of setting up decontamination zones, there’s little that can be done to curtail the accidental seeding of new areas with introduced species. Once there, these non-native species can create tremendous havoc on local ecosystems.  Introduced species may have no natural enemies or may be quicker growing or more aggressive than their native counterparts.

Superfast muscles

Some types of muscles, somewhat unimaginatively dubbed ‘superfast muscles’, can contract with amazing speed.  According to research led by Coen Elemans of the University of Denmark, the mammalian speed champion is a muscle bats use in echolocation.

Just before bats catch an insect in flight, they let loose a burst of sound to pinpoint the insect’s exact location in space.  That burst, known as the terminal buzz, is composed of over 190 separate calls per second.  The vocal apparatus needed to produce sound that quickly requires the fastest muscles yet found in mammals.  In contrast, human leg muscles are 100 times slower. The fastest muscles in the human body are used to slam our eyes shut, but even they take about a quarter of a second to function.

Interestingly, all superfast muscles appear to be involved in the production of sound.  For example, many birds use this sort of rapid firing to produce their varied songs. The fastest vertebrate muscles belong to the toadfish, which produces sound by vibrating the muscles in its swim bladder 200 times/second. 

Possible test for Alzheimer's disease

Alzheimer's disease (AD) affects more than 26 million people worldwide.  Although some of the symptoms can be temporarily alleviated, there is still no cure for this degenerative and ultimately fatal illness.  There may, however, be a way to predict who will succumb to AD, according to a new study.

The researchers examined the blood work of 86 people, half of whom went on to develop AD.  Among the differences were elevated levels of pregnancy zone protein (a protein normally found only in trace amounts in men or non-pregnant women) in women who went on to develop AD.  These women were over 60 years old and definitely not pregnant.  Intriguingly, pregnancy zone protein was produced in senile plaques within the brains of AD sufferers up to four years before the onset of symptoms.

Why is it so important to diagnose a disease for which there is no cure?  As I mentioned there are ways to postpone the end result and to temporarily keep symptoms to a minimum.  Early diagnosis is critical for this kind of treatment.  And who knows?  Perhaps for some people dementia can be staved off until a cure is found.

Clothes make the race

Although great strides have been made over the past decades to combat racism, prejudices still exist.  For example, Jonathan Freeman from Tufts University and his colleagues from the University of California, Irvine and from Stanford University have found that clothing really does make the man.

The researchers asked volunteers to categorize a series of computerized male faces as either black or white.  Participants were more likely to think images associated with business attire were white and images associated with janitor clothing were black.  In fact, mouse-tracking software indicated that even when subjects ultimately decided that an image associated with business attire was black, they tended to hesitate as if they were going to choose white.  The reverse was true for white faces in conjunction with working class clothing.  Participants seemed to be attracted to the ‘black’ option, even though they chose ‘white’.

 

Caption: Perception of race is altered by cues as simple as the clothes worn. Researchers at Tufts University, Stanford and University of California, Irvine found that computerized faces accompanied by business attire were more likely to be seen as white, whereas faces with blue-collar attire were more likely to be seen as black.

The work was published in PLoS ONE on Sept. 26, 2011.

Credit: Courtesy Tufts University

I should point out that of the 56 undergraduates participating in this study, 42 self-identified as white, and only three self-identified as black.  I would definitely like to see these experiments repeated with more minority students.  That said, it’s probably not a bad thing to be more aware of how contextual clues may be influencing our race perceptions.

Controlling hibernation

Tulasi Jinka, Øivind Tøien, and Kelly L. Drew of the University of Alaska Fairbanks were able to induce torpor in arctic ground squirrels, but only during their normal hibernation cycles.  They were also able to bring animals out of hibernation at will.

Hibernation involves lowering the metabolism to a nearly deathlike state, a condition known as torpor.  A hibernating animal might have a core body temperature barely above freezing, and use as little as one percent of the amount of oxygen it would require while active. 

One of the molecules known to regulate torpor is adenosine.  When this nucleotide binds to specific receptors, it inhibits the central nervous system.  In humans, this results in the drowsy feeling that tells us it’s time for bed.  In arctic ground squirrels, the binding of adenosine to its receptor induces hibernation.  Receptors like the one to which adenosine attaches can be bound by other molecules as well.  Agonists and antagonists also park at the receptor’s binding site, the former inducing the normal activity and the latter blocking it.  Caffeine is an example of an adenosine antagonist.

The researchers gave six ground squirrels adenosine agonists and antagonists at three different stages of their yearly cycles:  during the summer, at the very start of the hibernation period, and midway through hibernation.  During the last time period, squirrels were first woken up so that they could be put back to sleep.  The agonists induced torpor during the normal hibernation periods (and did so especially well in the squirrels awoken while already hibernating) but not all during the summer.  In contrast, an adenosine antagonist was able to reverse spontaneous entry into torpor. 

Besides generating a pack of extremely grouchy ground squirrels, this research might one day lead to more precise control of hibernation.  If so, perhaps humans, who after all also have adenosine receptors, could be brought into a state of torpor for medical or intergalactic travel purposes.