Each nation gets a blip and a flashing dot on the map whenever they detonate a nuclear weapon, with a running tally kept on the top and bottom bars of the screen. Hashimoto, who began the project in 2003, says that he created it with the goal of showing”the fear and folly of nuclear weapons.” It starts really slow — if you want to see real action, skip ahead to 1962 or so — but the buildup becomes overwhelming.

Researchers at the J. Craig Venter Institute (JCVI) published results today describing the successful construction of the first self-replicating, synthetic bacterial cell. The team synthesised the 1.08 million base pair chromosome of a modified Mycoplasma mycoides genome. The synthetic cell is called Mycoplasma mycoides JCVI-syn1.0 and is the proof of principle that genomes can be designed in the computer, chemically made in the laboratory and transplanted into a recipient cell to produce a new self-replicating cell controlled only by the synthetic genome.

This research will be published by Daniel Gibson et al in the 20th May edition of Science Express and will appear in an upcoming print issue of Science.

‘For nearly 15 years Ham Smith, Clyde Hutchison and the rest of our team have been working toward this publication today – the successful completion of our work to construct a bacterial cell that is fully controlled by a synthetic genome,’ said J. Craig Venter, Ph.D., founder and president, JCVI and senior author on the paper. ‘We have been consumed by this research, but we have also been equally focused on addressing the societal implications of what we believe will be one of the most powerful technologies and industrial drivers for societal good. We look forward to continued review and dialogue about the important applications of this work to ensure that it is used for the benefit of all.’

According to Dr Smith, ‘With this first synthetic bacterial cell and the new tools and technologies we developed to successfully complete this project, we now have the means to dissect the genetic instruction set of a bacterial cell to see and understand how it really works.’

To complete this final stage in the nearly 15 year process to construct and boot up a synthetic cell, JCVI scientists began with the accurate, digitised genome of the bacterium, M. mycoides. The team designed 1,078 specific cassettes of DNA that were 1,080 base pairs long. These cassettes were designed so that the ends of each DNA cassette overlapped each of its neighbours by 80bp. The cassettes were made according to JCVI’s specifications by the DNA synthesis company, Blue Heron Biotechnology.

The JCVI team employed a three stage process using their previously described yeast assembly system to build the genome using the 1,078 cassettes. The first stage involved taking 10 cassettes of DNA at a time to build 110, 10,000 bp segments. In the second stage, these 10,000 bp segments are taken 10 at a time to produce eleven, 100,000 bp segments. In the final step, all 11, 100 kb segments were assembled into the complete synthetic genome in yeast cells and grown as a yeast artificial chromosome.

The complete synthetic M. mycoides genome was isolated from the yeast cell and transplanted into Mycoplasma capricolum recipient cells that have had the genes for its restriction enzyme removed. The synthetic genome DNA was transcribed into messenger RNA, which in turn was translated into new proteins. The M. capricolum genome was either destroyed by M. mycoides restriction enzymes or was lost during cell replication. After two days viable M. mycoides cells, which contained only synthetic DNA, were clearly visible on petri dishes containing bacterial growth medium.

The initial synthesis of the synthetic genome did not result in any viable cells so the JCVI team developed an error correction method to test that each cassette they constructed was biologically functional. They did this by using a combination of 100 kb natural and synthetic segments of DNA to produce semi-synthetic genomes. This approach allowed for the testing of each synthetic segment in combination with 10 natural segments for their capacity to be transplanted and form new cells. Ten out of 11 synthetic fragments resulted in viable cells; therefore the team narrowed the issue down to a single 100 kb cassette. DNA sequencing revealed that a single base pair deletion in an essential gene was responsible for the unsuccessful transplants. Once this one base pair error was corrected, the first viable synthetic cell was produced.

Dr Gibson stated, ‘To produce a synthetic cell, our group had to learn how to sequence, synthesise, and transplant genomes. Many hurdles had to be overcome, but we are now able to combine all of these steps to produce synthetic cells in the laboratory.’ He added, ‘We can now begin working on our ultimate objective of synthesising a minimal cell containing only the genes necessary to sustain life in its simplest form. This will help us better understand how cells work.’

This publication represents the construction of the largest synthetic molecule of a defined structure; the genome is almost double the size of the previous Mycoplasma genitalium synthesis. With this successful proof of principle, the group will now work on creating a minimal genome, which has been a goal since 1995. They will do this by whittling away at the synthetic genome and repeating transplantation experiments until no more genes can be disrupted and the genome is as small as possible. This minimal cell will be a platform for analysing the function of every essential gene in a cell.

According to Dr Hutchison, ‘To me the most remarkable thing about our synthetic cell is that its genome was designed in the computer and brought to life through chemical synthesis, without using any pieces of natural DNA. This involved developing many new and useful methods along the way. We have assembled an amazing group of scientists that have made this possible.’

As in the team’s 2008 publication in which they described the successful synthesis of the M. genitalium genome, they designed and inserted into the genome what they called watermarks. These are specifically designed segments of DNA that use the ‘alphabet’ of genes and proteins that enable the researcher to spell out words and phrases. The watermarks are an essential means to prove that the genome is synthetic and not native, and to identify the laboratory of origin. Encoded in the watermarks is a new DNA code for writing words, sentences and numbers. In addition to the new code there is a web address to send emails to if you can successfully decode the new code, the names of 46 authors and other key contributors and three quotations: ‘TO LIVE, TO ERR, TO FALL, TO TRIUMPH, TO RECREATE LIFE OUT OF LIFE.’ – JAMES JOYCE; ‘SEE THINGS NOT AS THEY ARE, BUT AS THEY MIGHT BE.’ – A quote from the book, ‘American Prometheus’; ‘WHAT I CANNOT BUILD, I CANNOT UNDERSTAND.’ – RICHARD FEYNMAN.

The JCVI scientists envision that the knowledge gained by constructing this first self-replicating synthetic cell, coupled with decreasing costs for DNA synthesis, will give rise to wider use of this powerful technology. This will undoubtedly lead to the development of many important applications and products including biofuels, vaccines, pharmaceuticals, clean water and food products. The group continues to drive and support ethical discussion and review to ensure a positive outcome for society.

Funding for this research came from Synthetic Genomics Inc., a company co-founded by Drs. Venter and Smith.

Bats’ remarkable ability to ‘see’ in the dark uses the echoes from their own calls to decipher the shape of their dark surroundings. This process, known as echolocation, allows bats to perceive their surroundings in great detail, detecting insect prey or identifying threatening predators, and is a skill that engineers are hoping to replicate.

A team of British researchers has worked with six adult Egyptian fruit bats from Tropical World in Leeds to record and recreate their calls. These calls are pairs of ‘clicks’ from the bats’ tongues that they use to fill their surroundings with acoustic energy; the echoes that return allow the bats to form an image of their environment.

New research published today, Tuesday 11 May, in IOP Publishing’s Bioinspiration & Biomimetics, describes how engineers and biologists from the Universities of Strathclyde and Leeds worked with the bats to record their double-click echolocation call, and its returning echoes, using a miniature wireless microphone sensor mounted on the bat whilst in flight.

During echolocation, some bats are known to use a natural acoustic gain control. This allows them to emit high-intensity calls without deafening themselves, and then to hear the weak echoes returning from surrounding objects. The researchers replicated this system in electronics to allow the sensor to record both the emitted and reflected echolocation signals, providing an insight into the full echolocation process.

The six bats performed up to sixteen flights each along a flight corridor. Each flight was short – lasting only about three seconds – but, with the bats’ clicks only lasting a quarter of a millisecond, a large number of calls were recorded for the scientists to analyse.

Once back into the laboratory, the researchers were able to accurately recreate the echolocation calls using a custom-built ultrasonic loudspeaker. This technique will allow the signals and processes bats use to be applied to human engineering systems such as sonar. Specifically, the researchers are looking to apply these techniques in the positioning of robotic vehicles, used in structural testing applications.

Lead author Simon Whiteley from the Centre for Ultrasonic Engineering at the University of Strathclyde, said, “We aim to understand the echolocation process that bats have evolved over millennia, and employ similar signals and techniques in engineering systems. We are currently looking to apply these methods to positioning of robotic vehicles, which are used for structural testing. This will provide enhanced information on the robots’ locations, and hence the location of any structural flaws they may detect.”

A team of scientists from Columbia University, Arizona State University, the University of Michigan, and the California Institute of Technology (Caltech) have programmed an autonomous molecular “robot” made out of DNA to start, move, turn, and stop while following a DNA track.

The development could ultimately lead to molecular systems that might one day be used for medical therapeutic devices and molecular-scale reconfigurable robots—robots made of many simple units that can reposition or even rebuild themselves to accomplish different tasks.

A paper describing the work appears in the current issue of the journal Nature.

The traditional view of a robot is that it is “a machine that senses its environment, makes a decision, and then does something—it acts,” says Erik Winfree, associate professor of computer science, computation and neural systems, and bioengineering at Caltech.

Milan N. Stojanovic, a faculty member in the Division of Experimental Therapeutics at Columbia University, led the project and teamed up with Winfree and Hao Yan, professor of chemistry and biochemistry at Arizona State University and an expert in DNA nanotechnology, and with Nils G. Walter, professor of chemistry and director of the Single Molecule Analysis in Real-Time (SMART) Center at the University of Michigan in Ann Arbor, for what became a modern-day self-assembly of like-minded scientists with the complementary areas of expertise needed to tackle a tough problem.

Shrinking robots down to the molecular scale would provide, for molecular processes, the same kinds of benefits that classical robotics and automation provide at the macroscopic scale. Molecular robots, in theory, could be programmed to sense their environment (say, the presence of disease markers on a cell), make a decision (that the cell is cancerous and needs to be neutralized), and act on that decision (deliver a cargo of cancer-killing drugs).

Or, like the robots in a modern-day factory, they could be programmed to assemble complex molecular products. The power of robotics lies in the fact that once programmed, the robots can carry out their tasks autonomously, without further human intervention.

With that promise, however, comes a practical problem: how do you program a molecule to perform complex behaviors?

“In normal robotics, the robot itself contains the knowledge about the commands, but with individual molecules, you can’t store that amount of information, so the idea instead is to store information on the commands on the outside,” says Walter. And you do that, says Stojanovic, “by imbuing the molecule’s environment with informational cues.”

“We were able to create such a programmed or ‘prescribed’ environment using DNA origami,” explains Yan. DNA origami, an invention by Caltech Senior Research Associate Paul W. K. Rothemund, is a type of self-assembled structure made from DNA that can be programmed to form nearly limitless shapes and patterns (such as smiley faces or maps of the Western Hemisphere or even electrical diagrams). Exploiting the sequence-recognition properties of DNA base pairing, DNA origami are created from a long single strand of DNA and a mixture of different short synthetic DNA strands that bind to and “staple” the long DNA into the desired shape. The origami used in the Nature study was a rectangle that was 2 nanometers (nm) thick and roughly 100 nm on each side.

The researchers constructed a trail of molecular “bread crumbs” on the DNA origami track by stringing additional single-stranded DNA molecules, or oligonucleotides, off the ends of the staples. These represent the cues that tell the molecular robots what to do—start, walk, turn left, turn right, or stop, for example—akin to the commands given to traditional robots.

The molecular robot the researchers chose to use—dubbed a “spider”—was invented by Stojanovic several years ago, at which time it was shown to be capable of extended, but undirected, random walks on two-dimensional surfaces, eating through a field of bread crumbs.

To build the 4-nm-diameter molecular robot, the researchers started with a common protein called streptavidin, which has four symmetrically placed binding pockets for a chemical moiety called biotin. Each robot leg is a short biotin-labeled strand of DNA, “so this way we can bind up to four legs to the body of our robot,” Walter says. “It’s a four-legged spider,” quips Stojanovic. Three of the legs are made of enzymatic DNA, which is DNA that binds to and cuts a particular sequence of DNA. The spider also is outfitted with a “start strand”—the fourth leg—that tethers the spider to the start site (one particular oligonucleotide on the DNA origami track). “After the robot is released from its start site by a trigger strand, it follows the track by binding to and then cutting the DNA strands extending off of the staple strands on the molecular track,” Stojanovic explains.

“Once it cleaves,” adds Yan, “the product will dissociate, and the leg will start searching for the next substrate.” In this way, the spider is guided down the path laid out by the researchers. Finally, explains Yan, “the robot stops when it encounters a patch of DNA that it can bind to but that it cannot cut,” which acts as a sort of flypaper.

Although other DNA walkers have been developed before, they’ve never ventured farther than about three steps. “This one,” says Yan, “can walk up to about 100 nanometers. That’s roughly 50 steps.”

“This in itself wasn’t a surprise,” adds Winfree, “since Milan’s original work suggested that spiders can take hundreds if not thousands of processive steps. What’s exciting here is that not only can we directly confirm the spiders’ multistep movement, but we can direct the spiders to follow a specific path, and they do it all by themselves—autonomously.”

In fact, using atomic force microscopy and single-molecule fluorescence microscopy, the researchers were able to watch directly spiders crawling over the origami, showing that they were able to guide their molecular robots to follow four different paths.

“Monitoring this at a single molecule level is very challenging,” says Walter. “This is why we have an interdisciplinary, multi-institute operation. We have people constructing the spider, characterizing the basic spider. We have the capability to assemble the track, and analyze the system with single-molecule imaging. That’s the technical challenge.” The scientific challenges for the future, Yan says, “are how to make the spider walk faster and how to make it more programmable, so it can follow many commands on the track and make more decisions, implementing logical behavior.”

“In the current system,” says Stojanovic, “interactions are restricted to the walker and the environment. Our next step is to add a second walker, so the walkers can communicate with each other directly and via the environment. The spiders will work together to accomplish a goal.” Adds Winfree, “The key is how to learn to program higher-level behaviors through lower-level interactions.”

Such collaboration ultimately could be the basis for developing molecular-scale reconfigurable robots—complicated machines that are made of many simple units that can reorganize themselves into any shape—to accomplish different tasks, or fix themselves if they break. For example, it may be possible to use the robots for medical applications. “The idea is to have molecular robots build a structure or repair damaged tissues,” says Stojanovic.

“You could imagine the spider carrying a drug and bonding to a two-dimensional surface like a cell membrane, finding the receptors and, depending on the local environment,” adds Yan, “triggering the activation of this drug.”

Such applications, while intriguing, are decades or more away. “This may be 100 years in the future,” Stojanovic says. “We’re so far from that right now.”

“But,” Walter adds, “just as researchers self-assemble today to solve a tough problem, molecular nanorobots may do so in the future.”

The other coauthors on the paper, “Molecular robots guided by prescriptive landscapes,” are Kyle Lund and Jeanette Nangreave from Arizona State University; Anthony J. Manzo, Alexander Johnson-Buck, and Nicole Michelotti from the University of Michigan; Nadine Dabby from Caltech; and Steven Taylor and Renjun Pei from Columbia University. The work was supported by the National Science Foundation, the Army Research Office, the Office of Naval Research, the National Institutes of Health, the Department of Energy, the Searle Foundation, the Lymphoma and Leukemia Society, the Juvenile Diabetes Research Foundation, and a Sloan Research Fellowship.

Contact: Kathy Svitil ksvitil@caltech.edu

Image Credit: Courtesy of Paul Michelotti

PETMAN
“PETMAN is an anthropomorphic robot for testing chemical protection clothing used by the US Army. Unlike previous suit testers, which had to be supported mechanically and had a limited repertoire of motion, PETMAN will balance itself and move freely; walking, crawling and doing a variety of suit-stressing calisthenics during exposure to chemical warfare agents. PETMAN will also simulate human physiology within the protective suit by controlling temperature, humidity and sweating when necessary, all to provide realistic test conditions.”

Find out more about PETMAN here.

RiSE: The Amazing Climbing Robot.
“RiSE is a robot that climbs vertical terrain such as walls, trees and fences. RiSE uses feet with micro-claws to climb on textured surfaces. RiSE changes posture to conform to the curvature of the climbing surface and its tail helps RiSE balance on steep ascents.”

Find out more about RiSE here.

BigDog: The Most Advanced Rough-Terrain Robot on Earth
“BigDog is the alpha male of the Boston Dynamics robots. It is a rough-terrain robot that walks, runs, climbs and carries heavy loads. BigDog is powered by an engine that drives a hydraulic actuation system. BigDog has four legs that are articulated like an animal’s, with compliant elements to absorb shock and recycle energy from one step to the next. BigDog is the size of a large dog or small mule; about 3 feet long, 2.5 feet tall and weighs 240 lbs.”

Find out more about BigDog here.

Visit the Boston Dynamics website here.

Two new stud­ies of­fer rare glimpses in­to how chim­panzees deal with the deaths of those clos­est to them, sci­en­tists say.

Chimps’ “aware­ness of death is prob­ably more highly de­vel­oped than is of­ten sug­gested. It may be re­lat­ed to their sense of self-awareness, shown through phe­nom­e­na such as self-recognition and em­pa­thy,” said said James An­der­son of the Uni­vers­ity of Stir­ling in the U.K., who col­la­bo­rat­ed in one of the stud­ies.

In that re­search, An­der­son and col­leagues de­scribed the fi­nal hours and death of an old­er fe­male chimp liv­ing in a small group at a U.K. sa­fa­ri park as cap­tured on vid­e­o. In the oth­er stu­dy, sci­en­tists watched as two chimp moth­ers in the wild car­ried their in­fants’ mum­mi­fied re­mains for weeks af­ter they were lost to an ill­ness.

Re­search­ers have posted vid­e­os from both stud­ies on­line. Both stud­ies are pub­lished in the April 27 is­sue of the jour­nal Cur­rent Bi­ol­o­gy.

Few have wit­nessed chimps’ re­sponse at the mo­ment a mem­ber of their group dies, An­der­son said. Moth­er chimps have been known to car­ry their dead in­fants, he noted, and some ob­servers have seen the com­mo­tion that fol­lows when an adult chimp is lost to some sort of sud­den trau­ma.

“In con­trast to the fren­zied, noisy re­sponses to trau­matic adult deaths, the chim­panzees wit­ness­ing the fe­male’s death in our case were mostly calm,” An­der­son said.

In the days lead­ing up to the old­er chim­p’s death, the group was very qui­et and paid close at­ten­tion to her, the re­search­ers re­port. Right be­fore she died, she re­ceived much groom­ing and ca­ress­ing from the oth­ers, who seemed to test her for signs of life as she died. They left her soon af­ter, but her adult daugh­ter re­turned and re­mained by her moth­er all night, sci­en­tists said. When keep­ers re­moved the moth­er’s body the next day, the chim­panzees re­mained sub­dued and stayed that way for some time. For sev­er­al days they avoided sleep­ing on the plat­form where the fe­male had died, though it was nor­mally a fa­vored sleep­ing spot.

“In gen­er­al, we found sev­er­al si­m­i­lar­i­ties be­tween the chim­panzees’ be­hav­ior to­ward the dy­ing fe­male, and their be­hav­ior af­ter her death, and some re­ac­tions of hu­mans when faced with the de­mise of an eld­erly group mem­ber or rel­a­tive,” An­der­son said.

In the sec­ond stu­dy, Do­ra Bi­ro of the Uni­vers­ity of Ox­ford and her col­leagues wit­nessed the deaths of five mem­bers, in­clud­ing two in­fants, of a sem­i-i­so­lat­ed chimp com­mun­ity that re­search­ers have been stu­dying for over three dec­ades in forests around Bossou, Guin­ea.

“We ob­served the deaths of two young in­fants—both from a flu-like res­pi­ra­to­ry ail­ment,” Bi­ro said. “In each case, our ob­serva­t­ions showed a re­mark­a­ble re­sponse by chim­pan­zee moth­ers to the death of their in­fants: they con­tin­ued to car­ry the corpses for weeks, even months, fol­low­ing death.”

In that time, the corpses mum­mi­fied com­plete­ly, and the moth­ers showed care of the bod­ies rem­i­nis­cent of their treat­ment of live in­fants: they car­ried them ever­ywhere dur­ing their daily ac­ti­vi­ties, groomed them, and took them in­to their day and night nests dur­ing rest times, Bi­ro said. Over this ex­tend­ed pe­ri­od, they al­so be­gan to “let go” of the in­fants grad­u­al­ly, Bi­ro added. They al­lowed oth­er group mem­bers to han­dle them more and more often and tolerat­ed long­er pe­ri­ods of separa­t­ion from them, in­clud­ing in­stances where oth­er in­fants and ju­ve­niles were al­lowed to car­ry off and play with the corpses.

Oth­er group mem­bers showed some in­ter­est in the bod­ies, and al­most none showed any aver­sion to­ward the corpses, ac­cord­ing to Bi­ro and col­leagues. She not­ed that a mem­ber of her team made very si­m­i­lar ob­serva­t­ions fol­low­ing the death of one chim­pan­zee in­fant in Bossou back in 1992.

“Chim­panzees are hu­mans’ clos­est ev­o­lu­tion­ary rel­a­tives, and they have al­ready been shown to re­sem­ble us in many of their cog­ni­tive func­tions: they em­pa­thize with oth­ers, have a sense of fair­ness, and can co­op­er­ate to achieve goals,” Bi­ro said. “How they per­ceive death is a fas­ci­nat­ing ques­tion, and lit­tle da­ta ex­ist so far” con­cern­ing it.

“Our ob­serva­t­ions con­firm the ex­istence of an ex­tremely pow­er­ful bond be­tween moth­ers and their off­spring which can per­sist, re­mark­ably, even af­ter the death of the in­fant, and they fur­ther call for ef­forts to elu­ci­date the ex­tent to which chim­panzees un­der­stand and are af­fect­ed by the death of a close rel­a­tive or group-mate. This would both have im­plica­t­ions for our un­der­standing of the ev­o­lu­tion­ary ori­gins of hu­man per­cep­tions of death and pro­vide in­sights in­to the way chim­panzees in­ter­pret the world around them.”

Shooting lasers at the sky can make the germ of a raincloud, a new study shows. In an experiment that smacks of science fiction, scientists used a high-powered laser to squeeze water from air, both indoors and out.

Although the technique is unlikely to be an instant rainmaker anytime soon, it could plant the seeds for more eco-friendly cloud manipulation.

“This is the first time that a laser was used to condense water from both laboratory experiments and from the atmosphere,” says Jérôme Kasparian of the University of Geneva, a coauthor of the study. The work appeared in the May 2 Nature Photonics.

Atmospheric scientists have been trying to build artificial clouds since the 1940s, with mixed success. The most popular method, shooting particles of silver iodide into the sky, relied on the fact that raindrops need something to condense around.

“It’s just like when you take a shower with hot water — it’s very humid in your bathroom, but it’s not raining,” Kasparian says. Water droplets need a surface to condense on, like a mirror in a bathroom or a speck of dust or pollen in the atmosphere.

Previous experimenters hoped droplets would form around flakes of silver, salt or other materials just like on a bathroom mirror. “The idea is, you provide more condensation nuclei, you get more condensation,” Kasparian says. “It seems obvious, but in practice no one could really prove that it works.”

Kasparian and colleagues took inspiration from a mist-making apparatus that was invented in 1911 to detect cosmic rays, highly energetic subatomic particles that come from deep space. A physicist named Charles Wilson noticed that when cosmic rays strike a sealed container filled with water vapor, they leave a visible trail of water droplets behind them. This works because the cosmic rays knock electrons off the water molecules, leaving behind charged particles that act like specks of dust for water to congeal around.

“Our idea was to mimic what happens in a Wilson chamber,” Kasparian says. “If you get some condensation with cosmic rays, we should get even more condensation with a laser.”

Kasparian and his colleagues tested this idea by shooting a high-powered infrared laser into a cloud chamber. The laser shot extremely short pulses of intense light, which each carrying several terawatts — or a trillion watts — of energy.

The view fogged up immediately. Droplets about 50 micrometers in diameter formed first, and grew to about 80 micrometers in diameter over the next three seconds. “The effect in the cloud chamber was very spectacular and visible by bare eye,” Kasparian says. “We expected an effect, definitely. But that magnitude was pretty much a surprise.”

Next, the researchers took the laser out in the backyard to try it on the sky. They rolled the laser, called “Teramobile” for its terawatt power and its mobility, onto the lawn behind the physics building at the Free University of Berlin on several nights in the fall of 2008. The clouds, if they formed, would be too distant to see with the naked eye, so the team used a second laser to confirm the cloudy view.

“It also worked quite well in the free atmosphere,” Kasparian says. “That was quite surprising, and a very good surprise.”

Kasparian thinks lasers could provide a more reliable and environmentally friendly way to build clouds. “If you can seed clouds and get some control or at least modulation on the weather, the implications are huge for agriculture, many other economic sectors, many aspects of human life,” Kasparian says. “There are potentially huge consequences.”

“It is a clever technique,” says John Latham of the National Center for Atmospheric Research in Boulder, Colo. But he’s skeptical that laser-built clouds could actually make it rain on demand. “Rainfall production requires many conditions to be met,” he cautions.

Image Credit: Jean-Pierre Wolf / University of Geneva

Imagine if your fear of spiders, heights or flying could be cured with a simple injection. Research published in BioMed Central’s open access journal, Behavioural and Brain Functions suggests that one day this could be a reality.

The cerebellum, an area of the brain thought to be involved with the development of our fears, was studied in goldfish by researchers at the University of Hiroshima in Japan. Using classical conditioning, Masayuki Yoshida and Ruriko Hirano taught their fish to become afraid of a light flashed in their eyes. By administering a low voltage electric shock every time a light was shone, the fish were taught to associate the light with being shocked, which slowed their hearts – the typical fish reaction to a fright. Yoshida explains, ‘As you would expect, the goldfish we used in our study soon became afraid of the flash of light because, whether or not we actually gave them a shock, they had quickly learned to expect one. Fear was demonstrated by their heart beats decreasing, in a similar way to how our heart rate increases when someone gives us a fright.’

Humans can also be ‘trained’ to become afraid, and in fact, simple classical conditioning rooted in our childhood and early development can explain many of our behaviours. In this study however, the team discovered that fish that had first been injected in the cerebellum with lidocaine had stable heart rates and showed no fear when the light was shone – they were unable to learn to become afraid.

Since the brains of goldfish show many similarities with those of mammals, including humans, it is hoped that with further study it may soon be possible to understand more about the biological and chemical processes that cause us to become afraid. For the goldfish, the effect of lidocaine is only temporary – fearless fish return to being frightened fish as soon as the anaesthetic has worn off. Nevertheless, one day, our irrational phobias could become a thing of the past.

Combining observations from the CoRoT satellite and the ESO HARPS instrument, astronomers have discovered the first “normal” exoplanet that can be studied in great detail. Designated Corot-9b, the planet regularly passes in front of a star similar to the Sun located 1500 light-years away from Earth towards the constellation of Serpens (the Snake).

“This is a normal, temperate exoplanet just like dozens we already know, but this is the first whose properties we can study in depth,” says Claire Moutou, who is part of the international team of 60 astronomers that made the discovery. “It is bound to become a Rosetta stone in exoplanet research.”

“Corot-9b is the first exoplanet that really does resemble planets in our solar system,” adds lead author Hans Deeg. “It has the size of Jupiter and an orbit similar to that of Mercury.”

“Like our own giant planets, Jupiter and Saturn, the planet is mostly made of hydrogen and helium,” says team member Tristan Guillot, “and it may contain up to 20 Earth masses of other elements, including water and rock at high temperatures and pressures.”

Corot-9b passes in front of its host star every 95 days, as seen from Earth. This “transit” lasts for about 8 hours, and provides astronomers with much additional information on the planet. This is fortunate as the gas giant shares many features with the majority of exoplanets discovered so far.

“Our analysis has provided more information on Corot-9b than for other exoplanets of the same type,” says co-author Didier Queloz. “It may open up a new field of research to understand the atmospheres of moderate- and low-temperature planets, and in particular a completely new window in our understanding of low-temperature chemistry.”

More than 400 exoplanets have been discovered so far, 70 of them through the transit method. Corot-9b is special in that its distance from its host star is about ten times larger than that of any planet previously discovered by this method. And unlike all such exoplanets, the planet has a temperate climate. The temperature of its gaseous surface is expected to be between 160 degrees and minus twenty degrees Celsius, with minimal variations between day and night. The exact value depends on the possible presence of a layer of highly reflective clouds.

The CoRoT satellite, operated by the French space agency CNES, identified the planet after 145 days of observations during the summer of 2008. Observations with the very successful ESO exoplanet hunter — the HARPS instrument attached to the 3.6-metre ESO telescope at La Silla in Chile — allowed the astronomers to measure its mass, confirming that Corot-9b is indeed an exoplanet, with a mass about 80% the mass of Jupiter.

This finding is being published in this week’s edition of the journal Nature.

For the first time, a woman has given birth to two children after her fertility was restored using transplants of ovarian tissue that had been removed and frozen during her cancer treatment and then restored once she was cured.

Following her ovarian transplant, Mrs Stinne Holm Bergholdt gave birth to a girl in February 2007 after receiving fertility treatment to help her become pregnant. But then, in 2008, she discovered she had conceived a second child naturally and gave birth to another girl in September 2008.

Her doctor, Professor Claus Yding Andersen, reports her case in Europe’s leading reproductive medicine journal Human Reproduction. “This is the first time in the world that a woman has had two children from separate pregnancies as a result of transplanting frozen/thawed ovarian tissue,” he said. “These results support cryopreservation of ovarian tissue as a valid method of fertility preservation and should encourage the development of this technique as a clinical procedure for girls and young women facing treatment that could damage their ovaries.”

So far, nine children have been born worldwide as a result of transplanting frozen/thawed ovarian tissue (including Mrs Bergholdt’s two). Three have been born in Denmark after treatment carried out by Prof Andersen, who is Professor of Human Reproductive Physiology at the University Hospital of Copenhagen (Denmark). “Mrs Bergholdt gave birth to the first and the third babies and another woman delivered the second baby. This is the highest number of children born from one ovarian cryopreservation programme worldwide. It is interesting to note that nearly all of the nine pregnancies have occurred in Europe and so Europe is in the absolute forefront with this technology,” he said.

Mrs Bergholdt, from Odense, Denmark, who is also one of the authors of the paper, was diagnosed with Ewing’s sarcoma when she was 27 in 2004. Before she began chemotherapy, part of her right ovary was removed and frozen (her left ovary had been removed some years before because of a dermoid cyst, a type of benign ovarian tumour). Her cancer treatment was successful but, as expected, the drugs caused a menopause. In December 2005 six thin strips of ovarian tissue were transplanted back on to what remained of her right ovary. Her ovary began to function normally again and, after mild ovarian stimulation, she became pregnant and gave birth to her first daughter, Aviaja, in February 2007.

She breast-fed Aviaja until October 2007 and in January 2008 she returned to Prof Andersen’s fertility clinic for additional IVF treatment so that she could conceive again. However, a pregnancy test revealed she was already pregnant naturally, and in September she gave birth to a healthy girl, Lucca.

Prof Andersen said: “This showed that the original transplanted ovarian strips had continued to work for more than four years and that Mrs Bergholdt still has the capacity to conceive and give birth to healthy children. It is an amazing fact that these ovarian strips have been working for so long and it provides information on how powerful this technique can be. She continues to have natural menstrual cycles and, at present, is using pregnancy-preventing measures to avoid becoming pregnant again.
“She has seven more ovarian strips in the liquid nitrogen tank and may return, if she wishes so, to have more tissue transplanted in order to maintain her ovarian function once the current strips stop working. So, in total, by having around one third of an ovary removed she has the possibility of maintaining her ovarian function for many years. As long as the tissue remains properly stored in liquid nitrogen, it could remain functional for as long as 40 years. However, we do not know this for certain at present.”

Mrs Bergholdt, who is now 32, said: “When I found out I was pregnant for the first time I was of course very happy and excited – but also very afraid and sceptical since I found it very hard to believe that my body was really working again. My cancer had been diagnosed very late because the doctors didn’t take my complaints seriously at that time and kept on telling me that nothing was wrong, so I also wondered if it was really true that I was completely recovered from it. But eventually I started to believe that the pregnancy was really happening and began to enjoy every aspect of it.

“The second time it was quite a surprise to find out I was pregnant since we hadn’t been working on it – we thought we needed assistance like the first time. We had an appointment at the fertility outpatient clinic to talk about the possibility of a second baby, but it turned out that I was already pregnant – naturally. It was a very nice surprise to find out that my body was now functioning normally and that we were having a baby without having to go through the fertility treatment. It was indeed a miracle!”

Mrs Bergholdt said she and her husband had not decided yet whether they wanted more children. “The girls are still so small and need a lot of attention, but maybe in a couple of years we might think about it again.”

Will 2010 be the warmest year on record? How do the recent U.S. “Snowmageddon” winter storms and record low temperatures in Europe fit into the bigger picture of long-term global warming?

NASA has launched a new web page to help people better understand the causes and effects of Earth’s changing climate.

The new “A Warming World” page hosts a series of new articles, videos, data visualizations, space-based imagery and interactive visuals that provide unique NASA perspectives on this topic of global importance.

The page includes feature articles that explore the recent Arctic winter weather that has gripped the United States, Europe and Asia, and how El Nino and other longer-term ocean-atmosphere phenomena may affect global temperatures this year and in the future. A new video, “Piecing Together the Temperature Puzzle,” illustrates how NASA satellites monitor climate change and help scientists better understand how our complex planet works.

The new web page is available on NASA’s Global Climate Change Web site
at:
http://climate.nasa.gov/warmingworld

For more information about NASA and agency programs, visit:
http://www.nasa.gov

Giant plankton-eating fishes roamed the prehistoric seas for over 100 million years before they were wiped out in the same event that killed off the dinosaurs, new fossil evidence has shown.

An international team describe how new fossils from Asia, Europe and the US reveal a previously unknown dynasty of giant plankton-eating bony fishes that filled the seas of the Jurassic and Cretaceous periods, between 66-172 million years ago.

The team report their findings in this week’s Science.

‘Today’s giant plankton-feeders – such as baleen whales, basking sharks and manta rays – include the largest living vertebrate animals, so the fact that creatures of this kind were missing from the fossil record for hundreds of millions of years was always a mystery,’ said Dr Matt Friedman of Oxford University’s Department of Earth Sciences, an author of the report. ‘We used to think that the seas were free of big filter feeders during the age of dinosaurs, but our discoveries reveal that a dynasty of giant fishes filled this ecological role in the ancient oceans for more than 100 million years.’

Several of the most important new fossils came from deposits in Kansas in the USA, with other remains from as far afield as Dorset and Kent in the UK, and Japan. Some members of this filter-feeding fish group are estimated to have been up to 9 metres long, a similar size to modern plankton-eating giants such as the basking shark.

‘One of the reasons these big fishes were overlooked or misidentified lies in their anatomy,’ said Dr Friedman. ‘Over their evolutionary history, these fishes reduced the amount of bone in their skeletons, probably to save weight, with the consequence that most of their hard parts were easily scattered after death. As it turns out, the only parts you routinely find in the fossil record are their well-developed forefins.’

With few clues to go on, palaeontologists had argued that the owner of these isolated fins looked something like the modern-day swordfish. This changed when some of Dr Friedman’s colleagues began cleaning a fossil that preserved skull bones along with the fins.

Dr Friedman said: ‘Instead of finding a head with a long sword-like snout and jaws lined with predatory fangs, they found something completely different: long, toothless jaws supporting a gaping mouth, and long, rod-like bones that contributed to the huge gill arches needed to filter out enormous quantities of tiny plankton.’ The team named this fish Bonnerichthys, honouring the Kansas family who discovered the fossil.

Remains of similar giant plankton-eating fishes had been known from much older rocks, but they were thought to be a short-lived and unsuccessful evolutionary experiment. ‘As soon as we recognised that these animals had a longer history than anyone thought, I started examining museum collections and found more examples that had been overlooked or misidentified,’ explained Dr Friedman. Revisiting previously collected fossils netted the team evidence that these fishes thrived for millions of years and colonised many parts of the globe.

Intriguingly the ancestors of large modern filter-feeders such as baleen whales and whale sharks only appeared after the extinction of Bonnerichthys and its relatives, suggesting that today’s filter-feeders evolved to fill the ecological niche left behind by these plankton-eating contemporaries of the dinosaurs.

The research team consisted of scientists from Oxford University (UK), DePaul University, Chicago (US), Fort Hays State University, Kansas (US), University of Kansas (US), University of Glasgow (UK), and Triebold Paleontology Inc & Rocky Mountain Dinosaur Resource Centre, Colorado (US).

For more information contact Dr Matt Friedman on +44 (0)1865 272035 or email matt.friedman@earth.ox.ac.uk

Why do we find some people more attractive than others? What makes men look masculine and women look feminine? What can these facial distinctions tell us about our evolution? By drawing on examples from humans, apes and other primates, Dr Eleanor Weston discusses the differences between male and female faces, and the evolution of attractiveness.

Further Information
Dr Eleanor Weston is a mammalian palaeontologist based in the newly opened Darwin Centre at the Natural History Museum, London.
www.eleanorweston.net/sexual_dimorphism.html
www.nhm.ac.uk/visit-us/darwin-centre-visitors/marmontcentre/index.html

People who are usually happy, enthusiastic and content are less likely to develop heart disease than those who tend not to be happy, according to a major new study published today (Thursday 18 February).
The authors believe that the study, published in the Europe’s leading cardiology journal, the European Heart Journal, is the first to show such an independent relationship between positive emotions and coronary heart disease.

Dr Karina Davidson, who led the research, said that although this was an observational study, her study did suggest that it might be possible to help prevent heart disease by enhancing people’s positive emotions. However, she cautioned that it would be premature to make clinical recommendations without clinical trials to investigate the findings further.

“We desperately need rigorous clinical trials in this area. If the trials support our findings, then these results will be incredibly important in describing specifically what clinicians and/or patients could do to improve health,” said Dr Davidson, who is the Herbert Irving Associate Professor of Medicine & Psychiatry and Director of the Center for Behavioral Cardiovascular Health at Columbia University Medical Center (New York, USA).
Over a period of ten years, Dr Davidson and her colleagues followed 1,739 healthy adults (862 men and 877 women) who were participating in the 1995 Nova Scotia Health Survey. At the start of the study, trained nurses assessed the participants’ risk of heart disease and, with both self-reporting and clinical assessment, they measured symptoms of depression, hostility, anxiety and the degree of expression of positive emotions, which is known as “positive affect”.

Positive affect is defined as the experience of pleasurable emotions such as joy, happiness, excitement, enthusiasm and contentment. These feelings can be transient, but they are usually stable and trait-like, particularly in adulthood. Positive affect is largely independent of negative affect, so that someone who is generally a happy, contented person can also be occasionally anxious, angry or depressed.
After taking account of age, sex, cardiovascular risk factors and negative emotions, the researchers found that, over the ten-year period, increased positive affect predicted less risk of heart disease by 22% per point on a five-point scale measuring levels of positive affect expression (ranging from “none” to “extreme”).
Dr Davidson said: “Participants with no positive affect were at a 22% higher risk of ischaemic heart disease (heart attack or angina) than those with a little positive affect, who were themselves at 22% higher risk than those with moderate positive affect.

“We also found that if someone, who was usually positive, had some depressive symptoms at the time of the survey, this did not affect their overall lower risk of heart disease.
“As far as we know, this is the first prospective study to examine the relationship between clinically-
assessed positive affect and heart disease.”

The researchers speculate about what could be the possible mechanisms by which positive emotions might be responsible for conferring long-term protection from heart disease. These include influence on heart rates, sleeping patterns and smoking cessation.

“We have several possible explanations,” said Dr Davidson. “First, those with positive affect may have longer periods of rest or relaxation physiologically. Baroreflex and parasympathetic regulation may, therefore, by superior in these persons, compared to those with little positive affect. Second, those with positive affect may recover more quickly from stressors, and may not spend as much time ‘re-living’ them, which in turn seems to cause physiological damage. This is speculative, as we are just beginning to explore why positive emotions and happiness have positive health benefits.”

She said that most successful interventions for depression include increasing positive affect as well as decreasing negative affect. If clinical trials supported the findings of this study, then it would be relatively easy to assess positive affect in patients and suggest interventions to improve it to help prevent heart disease. In the meantime, people reading about this research could take some simple steps to increase their positive affect.
“Like the observational finding that moderate wine consumption is healthy (and enjoyable), at this point ordinary people can ensure they have some pleasurable activities in their daily lives,” she said. “Some people wait for their two weeks of vacation to have fun, and that would be analogous to binge drinking (moderation and consistency, not deprivation and binging, is what is needed). If you enjoy reading novels, but never get around to it, commit to getting 15 minutes or so of reading in. If walking or listening to music improves your mood, get those activities in your schedule. Essentially, spending some few minutes each day truly relaxed and enjoying yourself is certainly good for your mental health, and may improve your physical health as well (although this is, as yet, not confirmed).”

In an accompanying editorial by Bertram Pitt, Professor of Internal Medicine, and Patricia Deldin, Associate Professor of Psychology and Psychiatry, both at the University of Michigan School of Medicine (Michigan, USA), the authors pointed out that, currently, no-one knew whether positive affect had a direct or indirect causal role in heart disease, or whether there was a third, underlying factor at work, common to both conditions. Nor was it known for certain whether it was possible to modify and improve positive affect, and to what extent.

“Randomised controlled trials of interventions to increase positive affect in patients with cardiovascular disease are now underway and will help determine the effectiveness of increasing positive affect on cardiovascular outcome and will provide insight into the nature of the relationship between positive affect and cardiovascular disease,” they wrote.

“The ‘vicious cycle’ linking cardiovascular disease to major depression and depression to cardiovascular disease deserves greater attention from both the cardiovascular and psychiatric investigators……..These new treatments [to increase positive affect] could open an exciting potential new approach for treating patients with known cardiovascular disease who develop depression. If Davidson et al.’s observations and hypotheses stimulate further investigation regarding the effect of increased positive affect on physiological abnormalities associated with cardiovascular risk, perhaps it will be time for all of us to smile.”

Photo Credit: Photograph by Lennart Nilsson

Going about their day-to-day business, bees have no need to be able to recognise human faces. Yet in 2005, when Adrian Dyer from Monash University trained the fascinating insects to associate pictures of human faces with tasty sugar snacks, they seemed to be able to do just that. But Martin Giurfa from the Universite de Toulouse, France, suspected that that the bees weren’t learning to recognise people. ‘Because the insects were rewarded with a drop of sugar when they chose human photographs, what they really saw were strange flowers. The important question was what strategy do they use to discriminate between faces,’ explains Giurfa. Wondering whether the insects might be learning the relative arrangement (configuration) of features on a face, Giurfa contacted Dyer and suggested that they go about systematically testing which features a bee learned to recognise to keep them returning to Dyer’s face photos. The team publish their discovery that bees can learn to recognise the arrangement of human facial features on 29 January 2010 in the Journal of Experimental Biology at http://jeb.biologists.org.

Teaming up with Aurore Avargues-Weber, the team first tested whether the bees could learn to distinguish between simple face-like images. Using faces that were made up of two dots for eyes, a short vertical dash for a nose and a longer horizontal line for a mouth, Avargues-Weber trained individual bees to distinguish between a face where the features were cramped together and another where the features were set apart. Having trained the bee to visit one of the two faces by rewarding it with a weak sugar solution, she tested whether it recognised the pattern by taking away the sugar reward and waiting to see if the bee returned to the correct face. It did.

So the bees could learn to distinguish patterns that were organised like faces, but could they learn to ‘categorise’ faces? Could the insects be trained to classify patterns as face-like versus non-face like, and could they decide that an image that they had not seen before belonged to one class or the other? To answer these questions, Avargues-Weber trained the bees by showing them five pairs of different images, where one image was always a face and the other a pattern of dots and dashes. Bees were always rewarded with sugar when they visited the face while nothing was offered by the non-face pattern. Having trained the bees that ‘face-like’ images gave them a reward, she showed the bees a completely fresh pair of images that they had not seen before to see if the bees could pick out the face-like picture. Remarkably they did. The bees were able to learn the face images, not because they know what a face is but because they had learned the relative arrangement and order of the features.

But how robust was the bees’ ability to process the ‘face’s’ visual information? How would the bees cope with more complex faces? This time the team embedded the stick and dot faces in face-shaped photographs. Would the bees be able to learn the arrangements of the features against the backgrounds yet recognise the same stick and dot face when the face photo was removed? Amazingly the insects did, and when the team tried scrambling real faces by moving the relative positions of the eyes, nose and mouth, the bees no longer recognised the images as faces and treated them like unknown patterns.

So bees do seem to be able to recognise face-like patterns, but this does not mean that they can learn to recognise individual humans. They learn the relative arrangements of features that happen to make up a face-like pattern and they may use this strategy to learn about and recognise different objects in their environment.

What is really amazing is that an insect with a microdot-sized brain can handle this type of image analysis when we have entire regions of brain dedicated to the problem. Giurfa explains that if we want to design automatic facial recognition systems, we could learn a lot by using the bees’ approach to face recognition.

Article Credit: Science Centric

Autopsies remain the best way of finding out why someone died, but it’s not always the way it’s shown on TV. In this interactive event, you’ll have a chance to watch a virtual autopsy and talk to the people who perform the procedure. Come and find out how autopsies help doctors understand more about disease and provide information that benefits future generations.

Supported by The Royal College of Pathologists

Further Information

This event is being run by the Royal College of Pathologists. Pathologist John du Parcq, Mario Di Maggio and Ruth Semple from the Royal College of Pathologists will be running this event.

Feedback from this event in the past:
“This was an excellent event – very interesting and enjoyable.”
“I loved how interactive it was.”
“Thank you for an amazing Saturday.”

Related websites:
www.rcpath.org
www.nationalpathologyweek.org

View image here.

ESO has just released a stunning new image of the vast cloud known as the Cat’s Paw Nebula or NGC 6334. This complex region of gas and dust, where numerous massive stars are born, lies near the heart of the Milky Way galaxy, and is heavily obscured by intervening dust clouds.

Few objects in the sky have been as well named as the Cat’s Paw Nebula, a glowing gas cloud resembling the gigantic pawprint of a celestial cat out on an errand across the Universe. British astronomer John Herschel first recorded NGC 6334 in 1837 during his stay in South Africa. Despite using one of the largest telescopes in the world at the time, Herschel seems to have only noted the brightest part of the cloud, seen here towards the lower left.

NGC 6334 lies about 5500 light-years away in the direction of the constellation Scorpius (the Scorpion) and covers an area on the sky slightly larger than the full Moon. The whole gas cloud is about 50 light-years across. The nebula appears red because its blue and green light are scattered and absorbed more efficiently by material between the nebula and Earth. The red light comes predominantly from hydrogen gas glowing under the intense glare of hot young stars.

NGC 6334 is one of the most active nurseries of massive stars in our galaxy and has been extensively studied by astronomers. The nebula conceals freshly minted brilliant blue stars — each nearly ten times the mass of our Sun and born in the last few million years. The region is also home to many baby stars that are buried deep in the dust, making them difficult to study. In total, the Cat’s Paw Nebula could contain several tens of thousands of stars.

Particularly striking is the red, intricate bubble in the lower right part of the image. This is most likely either a star expelling large amount of matter at high speed as it nears the end of its life or the remnant of a star that already has exploded.

This new portrait of the Cat’s Paw Nebula was created from images taken with the Wide Field Imager (WFI) instrument at the 2.2-metre MPG/ESO telescope at the La Silla Observatory in Chile, combining images taken through blue, green and red filters, as well as a special filter designed to let through the light of glowing hydrogen.

A team of researchers including scientists from the University of Florida has shown insect colonies follow some of the same biological “rules” as individuals, a finding that suggests insect societies operate like a single “superorganism” in terms of their physiology and life cycle.

For more than a century, biologists have marveled at the highly cooperative nature of ants, bees and other social insects that work together to determine the survival and growth of a colony.

The social interactions are much like cells working together in a single body, hence the term “superorganism” — an organism comprised of many organisms, according to James Gillooly, an assistant professor in the department of biology at UF’s College of Liberal Arts and Sciences.

Now, researchers from UF, the University of Oklahoma and the Albert Einstein College of Medicine have taken the same mathematical models that predict lifespan, growth and reproduction in individual organisms and used them to predict these features in whole colonies.

By analyzing data from 168 different social insect species including ants, termites, bees and wasps, the authors found that the lifespan, growth rates and rates of reproduction of whole colonies when considered as superorganisms were nearly indistinguishable from individual organisms.

The findings will be published online this week in the Proceedings of the National Academy of Sciences.

“This PNAS paper regarding the energetic basis of colonial living in social insects is notable for its originality and also for its importance,” said Edward O. Wilson, a professor of biology at Harvard University and co-author of the book “The Super-Organism,” who was not involved in the research. “The research certainly adds a new perspective to our study of how insect societies are organized and to what degree they are organized.”

The study may also help scientists understand how social systems have arisen through natural selection — the process by which evolution occurs. The evolution of social systems of insects in particular, where sterile workers live only to help the queen reproduce, has long been a mystery, Gillooly said.

“In life, two of the major evolutionary innovations have been how cells came together to function as a single organism, and how individuals joined together to function as a society,” said Gillooly, who is a member of the UF Genetics Institute. “Relatively speaking, we understand a considerable amount about how the size of multicellular organisms affects the life cycle of individuals based on metabolic theory, but now we are showing this same theoretical framework helps predict the life cycle of whole societies of organisms.”

Researchers note that insect societies make up a large fraction of the total biomass on Earth, and say the finding may have implications for human societies.

“Certainly one of the reasons folks have been interested in social insects and the consequences of living in groups is that it tells us about our own species,” said study co-author Michael Kaspari, a presidential professor of zoology, ecology and evolutionary biology at the University of Oklahoma and the Smithsonian Tropical Research Institute. “There is currently a vigorous debate on how sociality evolved. We suggest that any theory of sociality be consistent with the amazing convergence in the way nonsocial and social organisms use energy.”

In addition to Gillooly and Kaspari, Chen Hou from the Albert Einstein College of Medicine, and Hannah B. Vander Zanden of the University of Florida participated in the study.

Professor Russell Foster explains how our internal body clock controls all aspects of our physiology and behaviour – from our sleep patterns, to our blood pressure, and even our physical strength. But what happens if we ignore our natural rhythms, and what are the effects of our increasingly 24/7 society? Come along to find out all you need to know about your biological clock.

Apologies about sound quality

Further Information

Professor Russell Foster is Professor of Circadian Neuroscience at the Nuffield Laboratory of Opthamology, University of Oxford. His is co-author of the two popular science books, ‘Rhythms of Life. The Biological Clocks that Control the Daily Lives of Every Living Thing’, and ‘Seasons of Life. The Biological Rhythms that Enable Living Things to Thrive and Survive’.
www.neuroscience.ox.ac.uk/directory/russell-foster

In the new block­bust­er film Av­a­tar, hu­mans vis­it the hab­it­a­ble—and in­hab­it­ed—al­ien moon Pan­do­ra. Life-bearing moons like Pan­do­ra or the Star Wars for­est moon of En­dor are a sta­ple of sci­ence fic­tion.

But hab­it­a­ble moons may soon be­come sci­ence fact, and could per­haps even ex­ist around the same star that il­lu­mi­nates the fic­tional Pan­do­ra, as­tro­no­mers say.

“If Pan­do­ra ex­isted, we po­ten­tially could de­tect it and study its at­mos­phere in the next decade,” said Li­sa Kal­te­neg­ger of the Har­vard-Smith­son­ian Cen­ter for As­t­ro­phys­ics in Cam­bridge, Mass.

A new pa­per by Kal­te­neg­ger ar­gues that NASA’s new James Webb Space Tel­e­scope, to be launched in 2014, will be able to study their at­mos­pheres and de­tect key gas­es like car­bon di­ox­ide, ox­y­gen, and wa­ter va­por.

So far, plan­et searches have spot­ted hun­dreds of Ju­pi­ter-sized ob­jects in a range of or­bits. Such gi­ant gas plan­ets, while eas­i­er to de­tect, could not serve as homes for life as we know it. How­ev­er, sci­en­tists have spec­u­lat­ed wheth­er a rocky moon or­bit­ing a gas gi­ant could be life-friendly, if that plan­et or­bited with­in the star’s hab­it­a­ble zone, the re­gion warm enough for liq­uid wa­ter to ex­ist.

“All of the gas gi­ant plan­ets in our so­lar sys­tem have rocky and icy moons,” said Kal­te­neg­ger. “That raises the pos­si­bil­ity that al­ien Ju­pi­ters will al­so have moons. Some of those may be Earth-sized and able to hold on­to an at­mos­phere.”

NASA’s space-based Kep­ler tel­e­scope looks for plan­ets that cross in front of their host stars, which cre­ates a mini-eclipse and dims the star by a small but de­tecta­ble amount. Such a trans­it lasts only hours and re­quires ex­act align­ment of star and plan­et along our line of sight.

Once they have found an al­ien Ju­pi­ter, as­tro­no­mers can look for or­bit­ing moons. A moon’s gra­vity would tug on the plan­et and ei­ther speed or slow its trans­it, de­pend­ing on wheth­er the moon leads or trails the plan­et. The re­sult­ing trans­it dura­t­ion varia­t­ions would in­di­cate the moon’s ex­istence.

Once a moon is found, the next ob­vi­ous ques­tion would be: Does it have an at­mos­phere? If it does, those gas­es will ab­sorb a frac­tion of the star’s light dur­ing the trans­it, leav­ing a ti­ny, tell­tale fin­ger­print to the at­mos­phere’s com­po­si­tion.

The sig­nal is strongest for large worlds with hot, puffy at­mos­pheres, but an Earth-sized moon could be stud­ied if con­di­tions are just right. For ex­am­ple, the separa­t­ion of moon and plan­et needs to be large enough that we could catch just the moon in trans­it, while its plan­et is off to one side of the star.

Kal­te­neg­ger cal­cu­lat­ed what con­di­tions are best for ex­am­in­ing the at­mos­pheres of al­ien moons. She found that Al­pha Cen­tau­ri A, the sys­tem fea­tured in Av­a­tar, would be an ex­cel­lent tar­get.

“Al­pha Cen­tau­ri A is a bright, near­by star very si­m­i­lar to our Sun, so it gives us a strong sig­nal,” Kalteneg­ger ex­plained. “You would only need a hand­ful of trans­its to find wa­ter, ox­y­gen, car­bon di­ox­ide, and meth­ane on an Earth-like moon such as Pan­do­ra.”

While Al­pha Cen­tau­ri A of­fers tan­ta­liz­ing pos­si­bil­i­ties, small, dim, red dwarf stars are bet­ter tar­gets in the hunt for hab­it­a­ble plan­ets or moons, she added. The hab­it­a­ble zone for a red dwarf is clos­er to the star, which in­creases the prob­a­bil­ity of a trans­it.

As­tro­no­mers have de­bat­ed wheth­er tid­al lock­ing could be a prob­lem for red dwarfs. A plan­et close enough to be in the hab­it­a­ble zone would al­so be close enough for the star’s gra­vity to slow it un­til one side al­ways faces the star. (The same pro­cess keeps one side of the Moon al­ways fac­ing Earth.) One side of the plan­et then would be baked in con­stant sun­light, while the oth­er side would freeze in con­stant dark­ness.

An moon in the hab­it­a­ble zone would­n’t face this di­lem­ma. The moon would be tid­ally locked to its plan­et, not to the star, and there­fore would have reg­u­lar day-night cy­cles just like Earth. Its at­mos­phere would mod­er­ate tem­per­a­tures, and plant life would have a source of en­er­gy moon-wide.

“Alien moons or­bit­ing gas gi­ant plan­ets may be more likely to be hab­it­a­ble than tid­ally locked Earth-sized plan­ets or super-Earths,” said Kal­te­neg­ger. “We should cer­tainly keep them in mind as we work to­ward the ul­ti­mate goal of find­ing al­ien life.”

Scott Fleming of the University of Florida has also argued that a single habitable-zone gas giant could serve as a “signpost” for perhaps several habitable moons.

Kalteneg­ger’s pa­per is posted on­line at the arXiv database of Cor­nell Un­ivers­ity in New York.

Image Credit: Da­vid A. Aguilar, CfA