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Archive for the ‘Astronomy’ Category

Enter the Trojans

Wednesday, August 18th, 2010

In astronomy, a Trojan is an asteroid or moon that shares an orbit with a larger asteroid or moon, but does not collide with it.  The Trojan orbits within one of the Lagrangian points of stability ahead or behind the main body.

Usually the asteroids which accompany Jupiter around its orbit come to mind when you mention the Trojans.  The Jupiter asteroids were the first discovered, and are believed to be almost as numerous as those in the asteroid belt.  Since the Jupiter Trojans were discovered, scientist have found “Trojans” in the orbits of Mars, Neptune, and Saturn.

Discovered in Jupiter’s orbit in 1906 (588 Achilles was the first one), there have been 4,076 Jupiter Trojans found so far.  There are believed to be over a million Jupiter Trojans larger than 1 km in diameter.  As in the main asteroid belt, the Trojans form asteroid “families”.  Currently, most scientist believe the Trojans are “captured” Kuiper Belt Objects.  Sometimes the “capture” appears to imperfect.  The comet Shoemaker-Levy 9 is believed to have been one such imperfect capture.

Currently there are only four known Mars Trojans, and seven around Neptune.  There may be many more Trojans than those recorded so far; we’re just not in a position to see them yet.  Perhaps when New Horizons passes Neptune…

Martian Trojans, image by Andrew Buck, all rights reserved

There is some speculation that the Trojans are a source for new short-period comets and Centaurs.  Considering the four discovered around Mars, that puts them in our very near back yard.

I have it on good authority my voice makes its cable TV premiere tonight | The Loom

Wednesday, August 18th, 2010

weeds440I have a strange job. A few weeks back I was wandering through the aisles of the local Walmart, searching for bug spray, when my phone rang. A very excited Robert Krulwich was calling. As I drifted past the potato chips and plasma-screen TVs, he declared to me with great excitement that I was going to be on the cable series Weeds.

Now, I’m pretty sure that if I had actually auditioned for the show, I would remember it. Or at least I could find some trace of the experience over on IMDB, searching for my name in the role of Pothead #8. So there I was at the store, getting totally lost trying to figure out what Krulwich was saying.

Gradually, the story emerged: a few months ago, I joined Krulwich and his partner in radio crime, Jad Abumrad to tape a couple segments for their fine show, RadioLab. In one of those segments, I describe the glories of parasites, focusing on one surgically fiendish wasp. Apparently the people at Weeds are RadioLab fans and sometimes work bits of it into their own show. And apparently, they are using my ramblings–at great length, I’m reliably informed–in the season premiere. What deeper meaning that Jad, Robert, and I could bring to their show, I can’t say–in part because I don’t have cable TV, so I’m not a regular viewer.

Suffice to say, it was a very long bug spray run. The new season airs tonight. If anyone sees it, fill me in! And if I can get my mitts on the clip, I’ll post it.

[Update: We've got it]


“..Do Some Research on Kissing!” | The Intersection

Wednesday, August 18th, 2010

Miriam Goldstein was kind enough to alert me of this charming panel up at Comically Vintage entitled, “When scientists meet.” For obvious reasons, it goes straight into the Science of Kissing Gallery!

comic

Submit your original photo or artwork for consideration here.


Astronomers Announce Priorities: Dark Energy, Exoplanets, Cosmic Origins | 80beats

Wednesday, August 18th, 2010

LSSTThere is a lot of space to explore and a limited amount of money to spend. So every ten years the National Research Council’s “Decadal Survey“ recommends which astronomy and astrophysics projects should get first dibs. Last week, the committee released their recommendations for 2012 through 2021. The projects that got the thumbs-up from astronomers would tackle big tasks, like hunting for dark energy and seeking out new exoplanets.

Though funding agencies (like NASA, the National Science Foundation, and the Department of Energy), Congressional committees, and the scientific community often use the survey to select the observatories on which to focus attention and resources, some were skeptical about this report given the 2001 survey’s recommendations and results.

Although these reports have always been influential—policymakers like scientists to rank their needs—only two of the seven major projects that appeared on the wish list in the 2001 survey have been funded, leading astronomers to wonder if the exercise is as useful as they’d like it to be. Previous surveys have also been faulted for providing unrealistic cost estimates, as low as a fifth of what certain missions have ended up costing. As a result, there has been considerable pressure on the committee that authored [Friday's] report to prioritize projects more effectively and estimate costs better. [Science Insider]

This time, the committee hoped to avoid these budget underestimates by evaluating the financial and technical risk of each project.

“I think at the time of the previous decadal survey, people didn’t appreciate the importance of taking a second look at the cost of things and not just taking the word of the people submitting the projects,” says astronomer Claire Max of the University of California in Santa Cruz, a member of the final survey committee. This time around, the panel hired an outside expert to help estimate the funding and technical risk of each project. [Nature News]

Nature News outlines the survey’s funding recommendations for a wide range of projects, but two observatories–one in space and one on the ground–seem most promising to the committee, fitting with the survey’s major three priorities.

The committee highlighted three main areas of science, none of which should be too surprising to those who follow the field: Cosmic Dawn, New Worlds and the Physics of the Universe. Or, how did all of this get here, are there planets like Earth nearby, and what makes up the universe? Projects that are well suited to answer these questions, as well as technologically feasible, were given high recommendations. [Discovery News]

In Space

The survey recommends the most funding for the Wide Field Infrared Survey Telescope (WFIRST), a joint project between NASA and the Department of Energy, which has an estimated cost of $1.6 billion. After an expected launch in 2020, WFIRST will record light from distant supernova among other things, and hopefully provide insights into the universe’s expansion and dark energy. Committee members also believe the telescope may help in the hunt for exoplanets.

“WFIRST not only gets at all the dark energy [priorities], but it also has significant capability in exoplanet science and will do outstanding work in infrared survey science,” Michael Turner, a cosmologist at the University of Chicago and the Kavli Institute for Cosmological Physics told physicsworld.com. Turner, who served on the 23-member committee for the decadal survey, also notes that the survey did not reject the idea of a possible collaboration with the European Space Agency (ESA) to combine its planned Euclid dark-energy mission with WFIRST. [Physics World]

On the Ground

The survey also recommends support for the $463 million Large Synoptic Survey Telescope (pictured above). When completed, the telescope will survey the entire sky every week with a three-billion pixel digital camera to help researchers understand dark matter, dark energy, supernovae, near-Earth asteroids, and Kuiper belt objects.

In placing the LSST atop its priority list, the report highlighted the telescope’s technical readiness and its “compelling science case and capacity to address so many of the science goals of this survey,” including exploring the fundamental physical makeup of the universe by probing the nature of dark matter and dark energy. [Scientific American]

The DISCOVER blog Cosmic Variance has more on all this: 
The Next 10 Years of Astronomy explains what the Decadal Survey means to astronomers 
The Next Decade of US Space Astronomy
The Next Decade of US Ground Based Astronomy

Image: LSST Corporation


Fake Facebook “Dislike” Button Leads to More Dislike | Discoblog

Wednesday, August 18th, 2010

facebookThey only wanted to show their disapproval. Friends eager to counterbalance all those Facebook “Likes” rushed to “Download the official DISLIKE button now” as received in a message. But, sadly, no dislike button was in store. Instead, installing the application provided users with several surveys and left their profiles vulnerable to spammer control. If there was ever a time to unleash their Dislike, this was it.

Yet, as Graham Cluley of the security firm Sophos told the BBC–mentioning a similar ploy that offered Facebookers the chance to see an anaconda vomiting up a hippo–such “survey scam” applications are nothing new:

“Anyone can write a Facebook app–these scams are constantly springing up.”

Perhaps Facebook should take note: Users were willing to sacrifice their security for the mere power to express negative feedback. Or, at least, the mere power to express negative feedback without typing.

Perhaps a compromise is in order? Unfortunately, a new Meh button application seems to need some tweaking. As in the Atlantic Wire:

Turns out, every time you click the “meh” button it registers your vote—allowing an individual user to “meh” something 10,000 times or more. That’s a lot of indifference.

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Image: Facebook


Genes and culture: OXTR gene influences social behaviour differently in Americans and Koreans | Not Exactly Rocket Science

Wednesday, August 18th, 2010

Korean_american

There are great plays and bad ones, but the playwright’s actual text is only one aspect of a production. The very same words can take on radically different meanings depending on the whims of the director, the abilities of the actors and the setting of the stage. The same is true of our genes and our environments. In cases where genes affect our behaviour, the same stretch of DNA can lead to very different deeds, depending on individual circumstances. Just as a production defines a play, environments and cultures alter the effects of certain genes.

Heejung Kim from the University of California has discovered a great example of this effect by studying a gene called OXTR (or the ‘oxytocin receptor’, in full). The gene creates a docking station for a hormone called oxytocin, which is involved in all sorts of emotions and social behaviours, from trust to sexual arousal to empathy.

Kim looked at a specific version of the OXTR gene, whose carriers are allegedly more social and sensitive. But this link between gene and behaviour depends on culture; it exists among American people, who tend to look for support in troubled times, but not in Korean cultures, where such support is less socially acceptable. Culture sets the stage on which the OXTR gene expresses itself.

OXTR varies from person to person, and the DNA ‘letters’ at particular spots can affect the way we behave. According to previous studies, people with a ‘G’ at one specific site tend to be more sensitive parents, more empathetic and less lonely than those with an ‘A’. But most of these studies have been done with white, Western people who are hardly representative of the world at large – in fact, they’re positively W.E.I.R.D.

To looked outside this “thin and rather unusual slice of humanity”, Kim compared 134 Korean students with 140 American ones, all with comparable splits of age, gender and background. Using a questionnaire, she measured how stressed each volunteer was feeling at that point in their lives, and how they cope with stress. As with previous studies, Kim found that Koreans are less likely than Americans to turn to their social circle for support and they get less out of doing so; they are more concerned about burdening their friends and straining their relationships.

The OXTR gene exerts its influence against the background of these contrasting cultural conventions. Distressed Americans with one or more copies of the G version were more likely to seek emotional support from their friends, compared to those with two copies of the A version. But for the Koreans, the opposite was true – G carriers were less likely to look for support among their peers in times of need (although this particular trend was not statistically significant). In both cases, the G carriers were more sensitive to the social conventions of their own cultures. But the differences between these conventions led to different behaviour.

And in a further example of the influence of the environment, Kim only found this pattern among people who were experiencing a lot of stress. In the low stress group, she found that Americans were indeed more likely to seek emotional support than Koreans, but their OXTR gene had no bearing on their choices.

Of course, Koreans and Americans differ not just in their cultures, but in their genes (including many others beyond OXTR). To account for that, Kim also worked with a small group of 32 Korean-Americans who were born and raised in the US, but were genetically Korean. Kim found that the link between OXTR and emotional support among these volunteers was much closer to the culturally similar Americans than the genetically similar Koreans.

Richard Ebstein, who has worked on OXTR before, says, “Overall, I would say it’s a very interesting finding… These types of studies are needed to help us get a better understanding of how it’s not just nature or nurture but rather the interplay between the two that contributes to how we deal with the social environment.” However, he’s not convinced (and nor am I) that Kim looked at enough people, particularly in the extra experiment with the Korean-Americans. Ebstein wants to see them repeat the results in a much larger group.

Even so, Kim’s results are compelling. They’re also unusual in looking for an interaction between genes and culture. Many studies have looked at how nature and nurture work together but in most cases, the “nurture” bit involves something social that’s either harsh or kind, such as loving or abusive parenting. In one of the most famous examples, people with the ‘low-activity’ version of the MAOA gene tend to be more aggressive than those with the ‘high-activity’ one, but only if they’ve been abused or neglected as children. Kim’s study stands out because it looks as cultural conventions instead, and Ebstein says that it “provides an interesting new avenue for researching gene-environment interactions.”

Kim also hopes that her work will encourage more scientists to investigate the ways in which genes and culture evolve together. She notes that the G version of OXTR is more common among white Americans than Korea. It’s tantalisingly possible that American culture has come to emphasise social support partly because more people have genes that skew them towards social behaviour. So genes constrain culture, while culture creates the stage on which genes exact their influence.

Reference: PNAS http://dx.doi.org/10.1073/pnas.1010830107

More on genes and environment:

If the citation link isn’t working, read why here


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Researchers Use Lasers to Control the Beating of a Heart | 80beats

Wednesday, August 18th, 2010

laser-pacemakerIn early 2010, some scientists offered their predictions for the new decade which this blog covered in the post, “Scientists Predict: The 2010s Will Be Freakin’ Awesome–With Lasers.” In what could be an early sign of that sunny prognostication coming true, researchers have announced that they’ve controlled the beating of an embryonic heart with an infrared laser beam. While the work is in its early stages, researchers say this remarkable advance will help them study heart disease and could one day lead to optical pacemakers.

 

The embryonic hearts in question came from quail eggs. Each quail embryo was only two or three days old so the heart measured just 2 cubic millimeters in volume; at that stage, the heart is essentially a clump of cells that hasn’t yet developed its four-chambered structure. The pulses of infrared light were delivered by an optical fiber that ended 500 micrometres from the embryo.

Before they switched on the laser, the heart beat once every 1.5 seconds, but firing the laser twice a second quickened the heartbeat to match the laser rate as long as the laser fired…. ”It worked beautifully: the heart rate was in lockstep with the laser pulse rate,” says [study coauthor] Duco Jansen of Vanderbilt University in Nashville, Tennessee. [New Scientist]

Several years ago, a different scientific team showed that laser pulses could set the pace of a cluster of heart cells in a petri dish, but the new study, published in Nature Photonics, marks the first time a laser has set the pace of an entire heart. Lead author Michael Jenkins of Case Western Reserve University says the technique will offer a new way to study heart development. 

“We want to know how congenital heart defects form, and how the heart’s rhythms during development affect it later on,” he says. “Having a noninvasive way to modify the heart rate would be useful.” [ScienceNOW]

At the energy level used the laser pulses didn’t appear to damage the cells, but the researchers intend to thoroughly investigate the safety of the process. They’ll also be looking into other details–like how exactly this mechanism works. At the moment, it’s still unclear.

They suggest that it might create a temperature gradient that can stimulate “action potential in excitable tissues,” as was also proposed in earlier work on clusters of cardiomyocytes. [Scientific American]

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Image: Salma Shaikhouni


Randi and the X-wing | Bad Astronomy

Wednesday, August 18th, 2010

Over on Randi’s site, they just posted this image of His Skepticalness and a familiar spaceship:

Randi_xwing

When I saw it, my first thought was, “I find your lack of faith… refreshing.”

How would you caption this picture?


Where writing is silent | Gene Expression

Wednesday, August 18th, 2010

In my post on Empires of the Word I observed that quite often the written record is silent on many matters which only language or genes tell us must have occurred. The Indo-Aryan character of the dominant language on the island of Sri Lanka seems to be a geographical anomaly in the least, but perhaps most strange of all is the existence of a language and ethnic group of clear Southeast Asian provenance on the island of Madagascar. To my knowledge Arab, Persian and South Asian sources do not record the existence of a prominent Southeast Asian maritime diaspora which spanned the Indian ocean in the years before 1000 A.D., but we know that it did exist. A new paper on the genetics of the island of Comoros fleshes out another piece of the puzzle, Genetic diversity on the Comoros Islands shows early seafaring as major determinant of human biocultural evolution in the Western Indian Ocean:

The Comoros Islands are situated off the coast of East Africa, at the northern entrance of the channel of Mozambique. Contemporary Comoros society displays linguistic, cultural and religious features that are indicators of interactions between African, Middle Eastern and Southeast Asian (SEA) populations. Influences came from the north, brought by the Arab and Persian traders whose maritime routes extended to Madagascar by 700–900 AD. Influences also came from the Far East, with the long-distance colonisation by Austronesian seafarers that reached Madagascar 1500 years ago. Indeed, strong genetic evidence for a SEA, but not a Middle Eastern, contribution has been found on Madagascar, but no genetic trace of either migration has been shown to exist in mainland Africa. Studying genetic diversity on the Comoros Islands could therefore provide new insights into human movement in the Indian Ocean. Here, we describe Y chromosomal and mitochondrial genetic variation in 577 Comorian islanders. We have defined 28 Y chromosomal and 9 mitochondrial lineages. We show the Comoros population to be a genetic mosaic, the result of tripartite gene flow from Africa, the Middle East and Southeast Asia. A distinctive profile of African haplogroups, shared with Madagascar, may be characteristic of coastal sub-Saharan East Africa. Finally, the absence of any maternal contribution from Western Eurasia strongly implicates male-dominated trade and religion as the drivers of gene flow from the North. The Comoros provides a first view of the genetic makeup of coastal East Africa.

In the paper they note that ~6% of the Y chromosomal lineages were Southeast Asian, while ~15% of mtDNA lineages were. That indicates that the Southeast Asian presence on the Indian ocean was a case of folk migration, men, women and children on the move. The data from Madagascar indicate something similar, both male and female lineages show Southeast Asian imprint among the highland Malagasy (I don’t make much of the proportional difference because this is just one sample). In contrast, they show in this paper that there’s a substantial West Eurasian (probably Arab, Indian and Persian) Y chromosomal gene flow into the population of Comoros, but no West Eurasian mtDNA. So in this case you have a clear contrast with that of the Southeast Asian seafarers, the Muslim merchants who settled on the Comoros did not bring their children or womenfolk. It was not a folk migration, but a mercantile network. Because of the nature of the sources, and the cultural influence of the West Asians, we know of their presence from the historical record. In contrast, the arguably more substantial folk migration of Southeast Asian seafarers from Borneo is hidden in the text. They may have been of no concern or beneath mention from the perspective of the Muslim merchant princes, but the fact that they were no longer on the high seas by the time the Portuguese arrive may also indicate that they were driven off by the same Muslim merchant princes in the years after 1000. If the latter is the case the silence may be due to the inclination to forget an unpleasant rivalry.

All this goes to show that history’s reliance on text can mislead and obscure real dynamics. Even social and economic history which attempts to tunnel-down to the level of the populace is still heavily reliant on written records. In the case of seafarers it seems likely that even archaeologists would be unable to detect their movements because of the liminal nature of their settlements. The linguistic and cultural influences in Madagascar and in East Africa indicate a sojourn by Austronesians in that coast, but there is no physical or textual record. There is the “dark history” which we ignore because of current ideological preferences, and then there is the dark history which has fallen outside of our methodological window.

Dienekes has more on this paper.

Can Greasy Fingerprints on Smart Phones Give Away Passcodes? | Discoblog

Wednesday, August 18th, 2010

androidThat grease trail you’ve smeared on your smart phone’s touchscreen could give away more than your lightsaber skills or virtual girlfriend’s whims: Would-be smudge attackers, a recent paper argues, could follow your finger oils as a clue to your passcode.

In the paper “Smudge Attacks on Smartphone Touchscreens,” which we first saw on Gizmodo, a team in the computer science department at the University of Pennsylvania tried to pick out grease patterns from Android phones by photographing the phones and enhancing the patterns with photo-editing software. From the paper’s introduction:

“We believe smudge attacks are a threat for three reasons. First, smudges are surprisingly persistent in time. Second, it is surprisingly difficult to incidentally obscure smudges through wiping or pocketing the device. Third and finally, collecting and analyzing oil residue smudges can be done with readily-available equipment such as a camera and a computer.”

android-passcodeThough the smudge alone can’t confirm the exact passcode, the study’s authors hint that it may help an attacker rule out possibilities. In the paper, the authors describe the three by three number grid of “contact points” that some earlier Android phones employed for entering passcodes. The team assumed three limitations on smudge patterns using this grid: it must have four or more contact points; it cannot use any contact point more than once; and if there is any contact point between two others on a smudge trail, then it must also be a contact point. They calculate that using just the last of these restrictions, an attacker could reduce the number of possible patterns from 1 million to 389,112 patterns–a way to reduce a phone lockout during hacking.

The study also investigated the best conditions for identifying a smudge pattern. A particularly easy partial pattern to find, the researchers say, appeared when the phone was “dirty prior to password entry,” i.e. after the user had just finished chatting, allowing the phone’s screen to soak up some extra face dirt for finger smudge contrast.

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Image: flickr / p_kim


NCBI ROFL: 101 uses for a dead body (mummification optional). | Discoblog

Wednesday, August 18th, 2010

103608130_15a2d20a73_zCadavers and mummies as therapeutic means

“Sickness befallen onto him, man found that plant and animal derivatives invigorated him. Thereafter, he found a therapeutic benefit in using man as a means of self cure and especially, dead man from violent death. The foam of the skull of cadaver was an excellent antiepileptic as well as blood coming out from a freshly decapitated man. By applying on diseased parts of his body, so as to get rid of inflammation or infection, cadaver’s hands were used against tumors of all kinds. Dead human skin were processed into belts and used therein for helping delivery of parturition women. The mummy must be blackish, foul smelling and hard. Those who were whitish, odorless and powder-like, were unfit for use. Mummy powder applied to the nose would stop nose bleeding. Ambroise Paré (1510-1590) was an adversary of those practices.”

mummies_used

Photo: flickr/Michael Scheltgen

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WTF is NCBI ROFL? Read our FAQ!


Happening Now: Spacewalking Astronauts Try to Fix ISS Coolant System | 80beats

Wednesday, August 18th, 2010

spacewalkThis morning, astronauts at the International Space Station are once again venturing outside of the ISS, undertaking the third spacewalk in their attempt to fix the station’s cooling system.

The crew is in no immediate danger, as their backup cooling system is working. However, the ammonia leak in the coolant system caused the astronauts to turn off some experiments and backup systems keep keep the ISS from overheating.

The space station has been working at reduced cooling capacity since the pump first failed on 31 July. The enormous pumps circulate ammonia in heat exchangers outside the station, where water cannot be used because it would freeze [BBC News].

During their first two spacewalks, one of which went on for eight hours, astronauts Douglas Wheelock and Tracy Caldwell Dyson removed the leaking old pump. This morning they managed to free the new one from the platform where spare parts are kept. It should take one more spacewalk after today’s to complete the job.

NASA station managers have said the ammonia pump failure has been one of the most challenging repairs for the International Space Station ever attempted. The cooling system is so critical to station operations that a pump repair is one of 14 major failures for which NASA engineers have prepared emergency plans for in advance, they added. There are four spare ammonia pumps on the space station, one of which will be used for this repair. Each pump weighs 780 pounds (353 kg) and is 5 1/2 feet long (1.6 meters) by 4 feet wide (1.2 meters) [Space.com].

Those of you who stayed up late last week to catch the Perseid meteor shower might be wondering whether all those rocks pose a threat to astronauts floating around outside the ISS. But NASA meteor experts say that even with Earth traveling through this haze of comet leftovers, the threat to astronauts is still less than that posed by the space junk orbiting our planet.

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80beats: Perseid Meteor Shower: When & Where To Catch the Sky Show

Image: NASA (2006 spacewalk)


Disease by coincidence – why we’re caught in the crossfire of a hidden war | Not Exactly Rocket Science

Wednesday, August 18th, 2010

Ecoli_dictyostelium

If you’re trapped in a building, it’s probably not the best time to start setting fire to things. But this is exactly what some bacteria do when they find themselves in a human; they cause diseases that are potentially fatal but not contagious. Without an escape, they risk going down with their host. This seems like a ludicrous strategy but we’re looking at it from the wrong perspective – our own. In truth, humans often have nothing to do with the diseases that plague us; we’re just collateral damage in an invisible war.

Like all living things, bacteria have to defend themselves against predators like amoebas. Some species do so using resistance genes that turn them from passive victims into aggressive fighters. And by coincidence, these same adaptations make them more virulent (good at causing disease) in human bodies. We’re just caught in the crossfire.

The idea that virulent bacteria have adapted to entirely different problems is called the “coincidental evolution hypothesis”. Sandrine Adiba from Pierre and Marie Curie University found evidence to support it by showing that the typically harmless gut bacterium Escherichia coli can cause disease in mice after it’s exposed to the threat of amoebas.

E.coli is mostly harmless, but some strains can cause severe food poisoning. When it’s not colonising the guts of mammals, it’s found in the soil; in both environments, it’s threatened by roving amoebas, which effectively engulf and digest it. Adiba found that one such predator – an amoeba called Dictyostelium discoideumwas very good at munching its way through harmless strains of E.coli, but a disease-causing strain known as 536 was too much to swallow.

Once engulfed, this hardy strain actually managed to reproduce inside the amoeba, weakening and eventually killing it. And if it can do that in a hungry amoeba, it can do that in a mammal cell; from its point of view, the two environments aren’t that different. Adiba confirmed that by pitting 31 different strains of E.coli against Dictyostelium. She found that those which tend to live in harmony with mammals also succumbed to amoebas, while resistant strains tend to cause disease.

The resistant strains had several genes that allowed them to avoid death by digestion. Some shield E.coli from enzymes called lysozymes that break down the outer walls of their cells. Others allow it to find food, by scavenging iron from within the amoeba’s body. These genes help to foil predators, but they’re also “virulence factors” that allow E.coli to successfully infect mammal cells. In fact, 76% of the resistant strains carry these weapons compared to just 16% of the vulnerable strains.

This was a single case study but it probably reflects a very common trend. Some scientists have suggested that for many bacteria, the ability to resist grazing amoebas came before the ability to cause disease in humans and other mammals. The former skill opened up the door to the latter.

There are many other examples that support this idea. Some E.coli strains wield poisons called Shiga toxins that are bad news for their hosts, but that also ward off a predator called Tetrahymena. When Salmonella enterica, another food poisoning germ, is threatened by amoebas, it ends up with more genetic variation at a part of its genome that affects how virulent it is.

Legionella pneumophila, which causes Legionnaires’ disease, might never even have been able to harm humans at all, were it not for amoebas. Legionella specialises in infecting our immune cells, including the macrophages that vacuum up foreign invaders. This ability to outsmart our defenders may again be coincidental; it’s more likely that the bacterium originally evolved to resist the digestive powers of amoebas, which also suck them up in the same way as macrophages.

And so far, we have just considered predators, which form one small part of the life of a bacterium. Competitors also shape their evolution. Earlier this year, I described how the normally harmless nose bacterium Streptococcus pneumonia becomes infectious when it battles against another species called Haemophilius influenzae. This competitor summons white blood cells to do away with Streptococcus, which can defend itself by producing a thicker coat. But this armour also allows Streptococcus to evade our own immune system, resulting in pneumonia, meningitis and other diseases. As I wrote back then, “many human diseases really have nothing to do with us at all.”

Reference: Adiba, S., Nizak, C., van Baalen, M., Denamur, E., & Depaulis, F. (2010). From Grazing Resistance to Pathogenesis: The Coincidental Evolution of Virulence Factors PLoS ONE, 5 (8) DOI: 10.1371/journal.pone.0011882

More on bacteria:

If the citation link isn’t working, read why here


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FOLLOWUP: X-Rayted calendar | Bad Astronomy

Wednesday, August 18th, 2010

eizo-february-small-11244In June, I posted about a pinup calendar where the model was somewhat more naked than naked: in fact, the pictures were all X-rays!

I was fascinated by the implied raciness of the pictures, given that at best all you could see was a hint of curves. The poses themselves were provocative as well, and I wanted to spark a discussion of it.

One thing that should have occurred to me but didn’t was how the pictures themselves were made. Was a model exposed to X-rays? How much were the images enhanced? Were they real at all?

Well, now I know. An article at Radiology Daily gives the lowdown: no models were irradiated in the making of the calendar. The pictures were all CGI, though based on models in Playboy.

The interesting thing about the article, though, is that they do discuss the implied raciness, just as I did:

“Obviously, we didn’t want to expose models to dangerous radiation,” [calendar art director] Schlichte said told Financial Times Deutschland. So the artists consulted a few issues of Playboy to determine “what poses look erotic if you’re not actually seeing anything,” she said. Then they had a computer generate those poses in skeletal form.

As for “not actually seeing anything,” that’s not quite accurate. Schlichte noted, “Anyone taking a close look at Miss April can see two silicon bags floating in front of her thorax.”

Ha! I was thinking of using April in my original article, but decided the more obvious breasts (and the more suggestive pose, truth be told) made it a bit too adult for the blog. I chose February, where they’re a bit less ostentatious.

All in all, I think this was an interesting idea, and it certainly did get the conversation going in the comments!

Tip o’ the lead fedora to Babloggee Eric B.


How Do We Change Public Attitudes and Behavior? | The Intersection

Wednesday, August 18th, 2010

In my recent OpEd with Michael Webber, we discuss the energy embedded in food waste–which accounts for at least 2% of the nation’s energy budget. We point out some ways to waste less such as reducing standard portion sizes and providing the right incentives for businesses, but acknowledge that ultimately, it comes down to consumer choices:

Foremost, the public needs to be better educated about proper storage of foods to keep them edible for longer. Shoppers could be supplied with easy-to-digest, accurate information about the proper shelf life of products, so that they are able to plan meals more carefully and end up with less spoilt food at the end of the week.

Another problem is “use by” dates, which are extremely conservative and can encourage consumers to throw away perfectly edible food. Similarly, “sell by” dates are usually meant as guidelines for retailers to ensure they do not keep stock too long, not as guidance to consumers about when the food will spoil. We need to improve the way we label foods.

Initiatives targeted at consumers could also have ripple-out effects: not only will educating people about food waste reduce pressure on their wallets, it would also lead to fewer trips to the store, saving on gasoline and reducing carbon emissions. Most important, it would help to promote a culture that places a higher value on food, energy, and the way their complex relationship affects us all.

S068.jpgBut tackling this issue will be very tricky. Consider: Everyday bakeries throw out day old goods, catering companies dump excess meals, supermarkets do away with blemished fruits, and that’s just the tip of the iceberg…

I’ve long been a firm believer in the power of personal choice and am curious to hear your ideas. How might we shift public attitudes to be less wasteful and save energy on a massive scale?


Empires of the Word & anti-Babel | Gene Expression

Wednesday, August 18th, 2010

Languages_of_EuropeTo the left you see a map of the distribution of languages and language families in Europe. Language is arguably the most salient cultural feature of our species, as well as one of the most obviously biologically embedded. The trait of language is a human universal, to the point where even those without hearing can create their own gestural languages de novo. But the specific nature of language as it is instantiated from region to region varies greatly. Language in the generality is a straightforward utility with which you communicate with your fellow man. But language also separates you from your fellow man.

European nationalism in the 19th and 20th centuries was in large part rooted in the idea that language defined the boundaries of a nation. During the Reformation era some German-speaking Roman Catholic priests declaimed the value of the bond of language against that of religion, praising those non-Germans who adhered to the Catholic cause against German speaking heretics (in the specific case the priest was defending Spanish tercios brought in by the Holy Roman Emperor to put down the rebellion of Protestant German princes). In the long centuries between the Reformation and the Enlightenment the idea of a Western Christian Commonwealth slowly melted in the face of the rise of vernacular, but even after the shattering of Western Christianity with the explosion of Reformations the accumulated capital of a unified Christian European elite persisted. Hungarian Protestant students at Oxford could make do with Latin even if they were totally innocent of English (see The Reformation). Newer lingua francas, French and later English, lack the deep unifying power of Latin in part because they are also living vernaculars. They may resemble Latin in some particulars of function, but eliding the differences removes far too much from the equation to be of any use. Linguistic diversity is a fact of our universe, but how it plays out matters a great deal, and has mattered a great deal, over the arc of history.

806-8This is the subject of Empires of the Word: A Language History of the World. Nicholas Ostler, the author, tackles an enormous subject here. He acknowledges the Herculean nature of his task in the introduction. And yet he does avoid some of the more intractable controversies within historical linguistics by constraining his subject matter to the period of history. That is, where we have some written records. This means that Ostler does not address the origins of the Indo-European language family, or the more recent expansion of the Bantus. Despite being separated by thousands of years these are both in the domain of pre-history, because we have no written records of proto-Bantu or proto-Indo-European. This does not mean that the book is not ambitious all the same. On the contrary, Empires of the Word takes on the “thicker” and messier tangle which is the association between language and fine-grained historical processes, social, cultural, economic and political. How history has shaped the nature and distribution of languages which we see extant in our world today is a labyrinth with many doors. Ostler doesn’t come close to opening the majority of those doors, but those he selects in Empires of the Word yield a rich number of surprises and insights, though he does not in the end seem to be able to generate a Grand Unified Theory of linguistic diversity and change from the welter of details.

top-20-languagesThere are two parallel threads throughout Ostler’s narrative: description and prediction. The latter is not prediction as a physicist would predict, rather, it is as a historical scientist might. Taking the data and producing models which can plausibly explain the phenomena we describe. Let’s take a look at the top 20 languages in the world. It seems that there are two primary ways that the speakers of a language can become numerous: rice & empire. Such a generalization is a bit glib, as many Mandarin speakers do not live by the “rice bowl,” but the big picture is that some languages gained adherents through “brute force,” pushing inexorably against the Malthusian possibilities of primary production and reproduction and assimilating smaller groups on the wave of advance of the speakers. The Asian languages on this list fall into that category. In contrast, you have the languages which spread with empire, exploration, and colonialism. English and Spanish are the exemplars of this class. Of the hundreds of millions of English and Spanish speakers a majority can not be accounted for simply by demographic expansion of the home countries. Rather, these languages colonized new lands, and acquired new speakers, rather rapidly over the past 500 years. Turkish is almost certainly in this category, though the transition from Greek, Armenian and Kurdish speech in Anatolia is less clearly understood because of thinner textual records of the process.

Of course the distinction between the two is somewhat artificial. The expansion of Mandarin, let alone the Chinese dialects, was almost certainly a synthesis of demographic expansion & migration, and linguistic assimilation of “barbarians.” Han Chinese are a genetically far less homogeneous than the Koreans or Japanese, in large part because the expansion of Han identity occurred over a diverse group of populations which were resident within China proper 2,000 years ago. Similarly, it seems implausible that the Vietnamese ethnically cleansed all the Malay and Khmer speaking populations along the Annamese coast as they pushed toward the Mekong delta. The genetic data in fact hint to a large scale assimilation of Malay Chams by the Vietnamese. Inversely, the rise of English was partially accompanied by the demographic explosion of British peoples, while Spaniards contributed a great deal genetically to the mestizo populations of the New World. So it is not rice or empire, but rice and empire. Albeit with different weights on a case-by-case basis.

“Rice” really refers to social, cultural and economic forces which bubble up from below and swallow up the numerous islands of linguistic diversity. “Empire” connotes the political and military structure which allows for the trickle down from above of imperial values and mores. But the two are also intimately connected. The Chinese state under the Ching Dynasty saw a rapid rise in population, and that rise was enabled in large part due to political stability. That stability fostered long term projects which increased the land under cultivation as well as public works infrastructure which could distribute grain so as to dampen the effect of local shocks. The Greek historian Polybius attributed the resiliency and strength of the Roman state in to its assimilative capacity, turning barbarians into citizens. The military and political resiliency of the Roman Empire through the Crisis of the Third Century was probably conditioned on the expansion of Romanitas from the the Atlantic to the Black Sea (the military core of the revival drew from the Latin speaking regions south of the Danube in the Balkans).

Just as the Roman Catholic Church is sometimes referred to as “the ghost of the deceased Roman Empire,” so the distribution of modern languages are tells of political, social and economic events of the past. Social and economic forces almost certainly loom large in language family explosions which Ostler did not cover, that of the Bantus, the Polynesians and Indo-Europeans. In the first case it seems that the Bantu peoples brought with them a new mode of production to east and south Africa. This was then a rice expansion, along with some genetic assimilation. The case of the Polynesians is more difficult, but the existence of a similar group in Madagascar, attests to the power of long distance seafaring techniques in scattering obscure peoples. Without the existence of Malagasy, both their genetic and linguistic uniqueness, the written record would not clue us in to the existence of an organized community of long distance seafaring Southeast Asians across the Indian ocean basin. Finally, the Indo-European expansion is more mysterious because it is so much further back in time, but it is also the most significant as nearly half the world’s population speaks an Indo-European language. David Anthony in The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World makes the case that a shift toward nomadic pastoralism enabled by the horse is the critical catalyst for the sweep of this language group from the Atlantic to the Bay of Bengal.

Though the Indo-European case is likely an ancient one Empires of the Word actually begins its story earlier. Ostler’s in depth knowledge of ancient Near Eastern linguistic history is frankly mind-blowing, and is arguably the most insightful and novel spin on the topic I’ve ever encountered. The extent of detailed and subtle grasp of the facts is awe inspiring. I did not know, for example, that the Elamites of southwest Iran once had their own writing system, which they eventually abandoned for Akkadian cuneiform. Ostler recounts the life-after-death which Sumerian experienced for over 1,000 years because of the nature of cuneiform itself, which was fitted to the Sumerian language, a linguistic isolate with no known relatives. For the last thousand years of cuneiform it was written in Akkadian, the first great Semitic language in the world, later to be succeeded by Aramaic, Punic, Hebrew, and Arabic. Parallel to the waxing and waning of these antique Semitic languages was the ebb and flow of ancient Egyptian, with its own peculiar form of writing.

One aspect of these ancient societies and their languages is the almost cold-blooded torpidity with which change occurred. Sumerian persisted as a liturgical language in what became Babylonia down to the Roman and Parthian period, 3,000 years of written history. The social-political entity which we term ancient Egypt arguably spanned 2,500 years, up until the final Persian conquest. Egyptian culture in a sense that the Pharaohs would recognize persisted for another 1,000 years, until the closure of the Temple of Philae under the orders of the Christian Emperor Justinian in the 6th century. This cut the last link with the literature and religion of ancient Egypt. Consider that the time between our own era and that of Jesus Christ is equivalent to that between the rise of the Egyptian polity and its decline in the late Bronze Age. Though there are certainly similarities between Paul of Tarsus and a modern Western man, a great many disruptions have broken chains of cultural continuity.

There may be one exception to this, and that is another language which arose just as Egypt went into decline, and that is Chinese. Classical Chinese in its written form remained relatively static between the ancient period of the first dynasties, and the early 20th century. This continuity is telling insofar as Western scholars never had to “discover” the history of the Chinese, they had always remembered it. The continuity of language, culture values, and political and ethnic identity, dovetailed together so that despite the reality that the architecture of China is ephemeral, its stories are not. In contrast, much of the literary corpus of the ancient Western world comes down to us only because of three intense periods of copying: the Carolingian Renaissance, 10th century translations in the Byzantine Empire, and the Abbasid translation project in the 9th century. The history of the societies before Greece was perceived only obliquely through the Bible and the classical authors. Modern archaeology and linguistics eventually unlocked the secrets of both hieroglyphics and cuneiform, but the reality that we did not know of the significance of the Hittites in the ancient world attests to the poverty of knowledge which lack of cultural continuity imposes (the great disruption between the Indus civilization and pre-Maurya India means that the script of the former remains lost to us).

The distribution and continuity of dead languages also is a signpost for that other aspect of human culture which is very powerful and ubiquitous: religion. Today most of the Latin spoken is “Church Latin,” and that is because of the languages sacred role within the Roman Catholic Church. Though Hebrew is the spoken language of the secular state of Israel thanks to a modern revival, for nearly 2,500 years it was a language of religion only, as the Jews adopted the languages of the people amongst whom they lived, Aramaic, Greek, Persian, Arabic, Latin, German, etc. The ancient languages of the Near East, Coptic from ancient Egyptian, and Syriac from Aramaic, persist as liturgical languages. It seems that so long as the gods do not die in the minds of believers the tongues of the ancients persist down the ages. So next to the language of rice and empire, you have languages of the gods.

As I indicated above Empires of the Word is rather thin on robust generalizations. But one point which the author mentions repeatedly is that the rise and fall of languages of great expanse and utility is the norm, not the exception. In particular, Nicholas Ostler takes time out to emphasize that languages which spread via trade often do not have long term staying power. Portuguese, Aramaic, Punic and Sogdian would fall into this category (the later success of Portuguese was a matter of rice and empire in Brazil). It seems that mercantile communities are too ephemeral, that successive historical shocks inevitably result in their decline when there isn’t a peasant demographic reservoir or imperial power which imposes it by fiat. Even those languages which eventually spread beyond traders and gain cultural and political cachet may fall from grace. Greek is the best case of this. It was the dominant language of the Roman East, and spoken as far as modern Pakistan, and studied in Dark Age Ireland. By the early modern period it was a strange and foreign language in the West, and with the rise of Islam in the east it lost its cultural glamor, and even those Christians in Arab lands who were Melkite, Greek Orthodox who adhered to the theological position of Constantinople, became Arab in speech and identity (in greater Syria the Greek Orthodox have been instrumental in the formulation of Arab nationalism).

And yet to some extent one must be cautious about over-reading the recession of Greek in the face of Arabic after the rise of Islam. Ostler repeats the conventional wisdom that the predominant vernacular in the Roman East was never Greek, but rather Semitic dialects descended from Aramaic. This is manifest in the fact that the Oriental Orthodox churches do not use Greek in their liturgy, but forms of Syriac. Their root is in an alternative intellectual tradition from that of the Greek Church. The transition to Arabic was then predominantly from a closely related Semitic language, not from Greek. One of the theses to explain the spread of Arabic across North Africa, but not into Persia, is that Arabic found it easier to replace other members of the Afro-Asiatic language family. I can accept that people can intuitively perceive differences of language family without a deep knowledge of said languages. In Sons of the Conquerors: The Rise of the Turkic World it is recounted that an ambassador to the court of the Hapsburg Emperor in Vienna communicated to the Sultan that apparently the locals spoke a dialect of Persian! Persian and German are of course both Indo-European languages, and set next to Turkish they may sound vaguely similar.

This thesis is plausible to me, and I have long held to it in regards to Arabic’s replacement of Aramaic. I have been told by a friend who is familiar with both languages (in addition to Hebrew) that they are rather close, and if not intelligible close enough to make language acquisition much easier. But Ostler extends the argument much further, suggesting that genetic affinity also explains the replacement of Egyptian and Berber dialects in North Africa. These are Afro-Asiatic languages, but they are not Semitic. I assume linguists do perceive similarities of character which can connect these languages, but what features span the Afro-Asiatic languages which would make language acquisition easier even at this remove of relationship? The Afro-Asiatic theory for the spread of Arabic is somewhat convenient in that it does explain the data well: Arabic has spread widely only in regions of other Afro-Asiatic languages, the exception being in Spain. And in Spain the Mozarab dialect had a stabilized existence with the Romance language of the rural areas, which eventually came back in the form of Castilian, Portuguese, etc. What Nicholas Ostler seems to be proposing is that the world of language acquisition is not flat. This is clearly true for closely related languages, but I think the thesis needs to be explored for distantly related languages from the same family. Does a native speaker of Marathi have a leg up on a Hungarian when it comes to learning Gaelic? I remain skeptical of the affirmative in that case.

So Empires of the Word outlines some broad generalizations of how languages grow, which seem born out by the record of history, and offers some more speculative theories about the importance of the cultural terrain upon which languages can flow and spread. But the narrative also lingers long on the future of the current lingua franca of our age, English. Nicholas Ostler does nothing to dismiss the omnipresence of English at the commanding heights of international culture. He reports for example that in 1994 50% of international telephone calls were between English speakers. 45% were between English speakers and those who were not English speakers! That means only 5% of international calls in 1994 were cases where people neither spoke English as their native language. I suspect that the numbers have changed a bit since then, but if that study is correct then it points to the awesome international spread of the English language. But Nicholas Ostler does not think that it will last, and his rationale seems to be the record of history, where such universal languages always fall. His next book, The Last Lingua Franca: English Until the Return of Babel outlines his thesis in detail.

And yet contra Ostler I have to suggest that perhaps this time it’s different. I do not believe that English in a unified form will dominate all. Already there has been considerable dialect drift. But the past 200 years are qualitatively different from what has come before, and there is already a revolution in communication technology. It may be that in the future languages do not crystallize as a function of geography, but perhaps more as a function of class and occupation. It does seem historically that trade lingua francas have been ephemeral in impact, and English, the language of McWorld, is the language of capital. But the modern world is much more dependent on flows of capital and commerce than the pre-modern world, the Sogdians and Portuguese were primarily vectors for high value luxury goods. Pre-modern capitalism had the air of a parlor game between the high and mighty, and was quite often in bad odor among rentier elites themselves. It is with reason that I observed above that the pace of cultural change in the past was less than what it is today. Positive feedback loops may be much more powerful than they once were, so that a “Globish” derived from English may quickly sweep away all comers, before it diversifies again.

But really I should wait for Ostler’s new book. The arguments I make here may be addressed, or I may misunderstood what I gleaned from Empires of the Word. It is as I said a story with rich and vibrant detail, much of which I glossed over, or did not address. For that Ostler’s tale is worth the time it takes to complete it. But there is I must say a lack of theoretical punch and heft. Perhaps this is just a function of the subject domain, which has too much complexity to distill down to any model of elegance or tractability. But I suspect a more rigorous analytical framework could squeeze some juice out of the enormous pile of detail which Nicholas Ostler has at his disposal. Perhaps he should read Replicated Typo.

Image Credit: Wikimedia, Ethnologue

Open Thread – August 16th, 2010 | Gene Expression

Wednesday, August 18th, 2010

The usual. If it’s off topic, etc., leave it here.

China is #2 | Gene Expression

Wednesday, August 18th, 2010

China Passes Japan as Second-Largest Economy:

After three decades of spectacular growth, China passed Japan in the second quarter to become the world’s second-largest economy behind the United States, according to government figures released early Monday.

The milestone, though anticipated for some time, is the most striking evidence yet that China’s ascendance is for real and that the rest of the world will have to reckon with a new economic superpower.

The recognition came early Monday, when Tokyo said that Japan’s economy was valued at about $1.28 trillion in the second quarter, slightly below China’s $1.33 trillion. Japan’s economy grew 0.4 percent in the quarter, Tokyo said, substantially less than forecast. That weakness suggests that China’s economy will race past Japan’s for the full year.

Lots of prose. Here’s another way to explore relationships, via Google Data Explorer.

Amplifying Our Brain Power Through Better Interactive Holographics | Science Not Fiction

Wednesday, August 18th, 2010

iron_man_2_holographics5Think of the most complicated thing you’ve written. Maybe it was a report for your employer, or an essay while in college. It could even be a computer program. Whatever it was, think of all the stuff you packed into it. Now, pause for a moment to imagine creating all that without using a word processor or a paper and pen, or really anything at all to externalize thought to something outside of your head. It seems impossible. What we get with this technology–ancient as it is–is an amplification of our brain power. Besides their gorgeous techy looks, do interactive holographics like that shown in Iron Man 2, reminiscent of interfaces shown in Minority Report, offer up some of the same brain amping?

While I was still a doctoral student, I had the opportunity work with a relative of interactive holographics, 3D virtual reality data CAVEs. This particular one, at the National Center for Supercomputing Applications (NCSA) in Urbana Illinois (the birthplace of HAL) circa 1999, was a cube with back projection on five of the six walls. You wore a headset that tracked your head position and orientation, and goggles that were LCD screens that blocked images to your right eye when the projectors were rendering images for your left eye, and vice versa when the projector was displaying images for your right eye. As you walk through space or move your head, what you see in the virtual space changes as you would expect it to.

The problem that had pushed me to use this system was trying to analyze 3D motion data of a fish that I was conducting research on. I’d developed a motion capture system for the fish, which gave fantastic 3D data of the fish moving while it was attacking its prey, but looking at this 3D data on 2D computer monitors turned out to be quite difficult. Even replaying the motion from several different views didn’t quite do the trick. So Stuart Levy at NCSA put my data set into a system called “Virtual Director” and I was able to playback the data in the cave. It was something of an unbelievable experience the first time I tried it – suddenly I could walk around the animal as it engaged in its behavior, manipulate it to get any view, rotate the wand I held to wind the behavior forward or back at different speeds. Visitors particularly enjoyed my “Book of Jonah” demo where I positioned them so that they ended going into the mouth of the fish during a capture sequence.

For my technical problem, the VR CAVE was appropriate technology: 3D display and interaction for an inherently 3D data set. It helped me see patterns in the data that I had not clearly seen before, which were incorporated into some of my subsequent publications that analyzed the movement data. It was worth the effort, and the physicality of it was fine since I didn’t need to spend multiple days working through the data.

Other uses of these kinds of “direct manipulation” interfaces that mix 3D data and real world interaction have not found such a receptive audience, as people complain that it seems tiring to make sweeping (if dramatic) gestures to go through photos that would just as well be navigated through with an arrow key. As someone who still uses “vi” to edit my text with, I can relate to criticisms of interfaces that offer more than is needed.

The important question, for any given interface, is whether simplifies difficult problems of control or analysis, or gets in the way. My former colleague Don Norman at Northwestern University has contributed a great deal to our understanding of this question, in books like The Design of Everyday Things. One of my favorite examples from that book considers two different interfaces to manipulating the position of a car seat. In one interface, on a luxury American car, there is a panel of knobs and buttons almost hidden below the left side of the dashboard. To go from a state of discomfort to a new chair position requires translating your discomfort into a series of knob pulls and twists on a console of many controls with tiny labels below each. In contrast, a German luxury car had a small version of the driver’s chair in the dashboard. To move the back of your chair down, you manipulated the chair in the dashboard accordingly; to move it forward, you would move it in the direction the chair was facing, and so on. One interface placed a large cognitive load on the user to solve the discomfort problem, while the other placed minimal demands.

Another favorite example is the “speed bug” – a tab that a plane pilot puts on the edge of an airspeed indicator to mark the velocities for critical changes to shape of the wing. Were it not for those bugs, the pilot would have to remember the velocity to do the wing adjustments – and that’s not easy, because it changes with things like the weight of the plane.

The virtual fish, miniature car seat adjuster, and speed bug are all examples of interfaces that make problems easier, and in this sense, amplify our brain power. Interactive holographic interfaces can do the same for problems where space is a convenient or needed basis for navigating the information. This isn’t always apparent in sci-fi depictions of these interfaces, but their use speaks to our hope that such 3D holographic wizardry will help us cope with the flood of data we contend with on a daily basis.


Pocket science – swordfish and flatfish are close kin, and ancient death-grip scars | Not Exactly Rocket Science

Tuesday, August 17th, 2010

Marlin_turbot

Flatfish are the closest living relatives to swordfish and marlins

At first glance, a swordfish and a flounder couldn’t seem more different. One is a fast, streamlined hunter with a pointy nose, and the other is an oddly shaped bottom-dweller with one distorted eye on the opposite side of its face. Their bodies are worlds apart, but their genes tell a different story.

Alex Little from Queen’s University, Canada, has found that billfishes, like swordfish and marlin, are some of the closest living relatives to the flatfishes, like plaice, sole, flounder and halibut. This result was completely unexpected; Little was originally trying to clarify the relationship between billfishes and their supposed closest relatives – the tunas. That connection seems to make more sense. Both tunas and billfishes are among a handful of fish that are partially warm-blooded. They can heat specific body parts, such as eyes and swimming muscles, to continuously swim after their prey at extremely fast speeds with keen eyesight.

But it turns out that these similarities are superficial. Little sequenced DNA from three species of billfishes and three tunas, focusing on three parts of their main genome and nine parts of their mitochondrial one (a small accessory genome that all animal cells have). By comparing these sequences to those of other fish, Little found that the billfishes’ closest kin are the flatfish and jacks. Indeed, if you look past the most distinctive features like the long bills and bizarre eyes, the skeletons of these groups share features that tunas lack. Indeed, billfish and tuna proved to be only distant relatives. Their ability to heat themselves must have evolved independently and indeed, their bodies product and retain heat in quite different ways.

Little’s work is testament to the power of natural selection. Even closely related species, like marlins are flounders, can end up looking vastly different if they adapt to diverse lifestyles. And distantly related species like tuna and swordfish can end up looking incredibly similar because they’ve adapted to similar challenges – pursuing fast-swimming prey. This shouldn’t come as a surprise – a few months ago, a French team found that prehistoric predatory sea reptiles were probably also warm-blooded.

Reference: Molecular Phylogenetics and Evolution: http://dx.doi.org/10.1016/j.ympev.2010.04.022; images by Luc Viatour and NAOA

Ant_scars

Ancient death-grip scars caused by fungus-controlled ants

Forty-eight million years ago, some ants marched up to a leaf and gripped it tight in their jaws. It would be the last thing they would ever do. Their bodies had already been corrupted by a fungus that, over the next few days, fatally erupted from their heads. The fungus produced a long stalk tipped with spores, which eventually blew away, presumably to infect more ants. In time, all that was left of this grisly scene were the scars left by the ants’ death-grip. Today, David Hughes from Harvard University has found such scars in a fossilised leaf from Germany.

Today, hundreds of species of Cordyceps fungi infect a wide variety of insects, including ants. Like many parasites, they can manipulate the way their hosts behave. One species, Cordyceps unilateralis, changes the brains of its ant hosts so that they find and bite into leaves, some 25cm above the forest floor. The temperature and humidity in this zone are just right for the fungus to develop its spore capsules. In its dying act, the ant leaves a distinctive bite mark that’s always on one of the leaf’s veins on its underside. And that’s exactly what Hughes saw in his fossil leaf.

Hughes originally thought that the marks were made by an insect cutting the veins of the leaf to drain away any potential poisons, something that modern insects also do. But these marks look very different – those on the fossil leaf bear a much closer resemblance to those of Cordyceps-infected ants. This is the first fossil trace of a parasite manipulating its host, but it’s not the oldest evidence for such a relationship. In 2008, another American group found a 105-million-year-old piece of amber containing a scale insect, with two Cordyceps stalks sticking out of its head. The war between insects and their Cordyceps nemeses is an ancient one indeed.

Reference: Biology Letters http://dx.doi.org/10.1098/rsbl.2010.0521
If the citation link isn’t working, read why here


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