Koala Bears May Be the 'Pickiest' Marsupials Around

Koalas may be the pickiest marsupials around: They evolved to feed almost exclusively on the leaves of Eucalyptus trees, and they are highly selective when it comes to which species and even which individual trees they visit. When the furry leaf-eater settles on a particular tree, it relies on a number of factors, including taste, to make its selection. In a study published in the November issue of Ecology, a journal of the Ecological Society of America (ESA), researchers used koala feeding preferences to design a new method that could help ecologists and conservationists map habitats.

Ben Moore and colleagues from the Australian National University and the Macaulay Land Use Research Institute in Scotland collected and analyzed leaves from all the trees available to koalas in a Eucalyptus woodland using a near-infrared spectroscopic model. To define "palatability" in koala terms, the researchers tested leaves on captive koalas and recorded how much they ate: They found that the koalas ate less foliage when it contained lots of lipid-soluble phenolic chemicals known as formylated phloroglucinol compounds (FPCs). The researchers then tracked koala tree visits in a Eucalyptus woodland to show that tree preferences of wild koalas could be predicted using the taste preferences of the captive koalas. The researchers also determined the chemical composition of the trees' leaves and other factors such as tree size and neighborhood quality, or how attractive each tree's neighbors were to koalas.

Specifically, koalas spend more time in large trees; however, the individual trees they prefer depend on the taste of the leaves and the "neighborhood" in which the tree is growing. Although tree size and taste are most important to the koalas, the researchers found that trees were visited more often if they were surrounded by smaller, less palatable trees or by larger, more palatable trees. Moore and colleagues explained that trees surrounded by smaller, unpalatable trees were probably more attractive by comparison. At the other extreme, trees surrounded by other large, palatable trees were visited more frequently because koalas were attracted to these high-quality areas.

"This method uses a new technique to combine our understanding of animal behavior with the chemical, spatial and physical aspects of the environment to make a map of koala habitat, as koalas see it," said Moore. "Our approach can aid ecologists in tracking and examining the presence or absence of animal populations in different areas -- and it can measure plants' susceptibility to herbivory -- by determining the quality and value of a habitat from the herbivore's point of view."

Shrouded Burst of Stars: Spitzer Reveals a Buried Explosion Sparked by a Galactic Train Wreck

Astronomers using NASA's Spitzer Space Telescope have found a stunning burst of star formation that beams out as much infrared light as an entire galaxy. The collision of two spiral galaxies has triggered this explosion, which is cloaked by dust that renders its stars nearly invisible in other wavelengths of light.
The starburst newly revealed by Spitzer stands as the most luminous ever seen taking place away from the centers, or nuclei, of merging parent galaxies. It blazes ten times brighter than the nearby Universe's previous most famous "off-nuclear starburst" that gleams in another galactic smashup known as the Antennae Galaxy.

The new findings show that galaxy mergers can pack a real star-making wallop far from the respective galactic centers, where star-forming dust and gases typically pool.

"This discovery proves that merging galaxies can generate powerful starbursts outside of the centers of the parent galaxies," says Hanae Inami, first author of a paper detailing the results in the July issue of The Astronomical Journal. Inami is a graduate student at The Graduate University for Advanced Studies in Japan and the Spitzer Science Center at the California Institute of Technology. She adds: "The infrared light emission of the starburst dominates its host galaxy and rivals that of the most luminous galaxies we see that are relatively close to our home, the Milky Way."

"No matter how you slice it, this starburst is one of the most luminous objects in the local Universe," agrees Lee Armus, second author of the paper and a senior research astronomer also at the Spitzer Science Center.

A dazzling galactic dust-up

Inami, Armus and their colleagues spotted the buried starburst with Spitzer in the interacting galaxies known as II Zw 096. This galactic train wreck -- located around 500 million light years away in the constellation Delphinus (the Dolphin) -- will continue to unfold for a few hundred million years. Gravitational forces have already dissolved the once-pinwheel shape of one of II Zw 096's pair of merging galaxies.

The ultra-bright starburst region spans 700 light-years or so -- just a tiny portion of II Zw 096, which streams across some 50,000 to 60,000 light-years -- yet it blasts out 80 percent of the infrared light from this galactic tumult. Based on Spitzer data, researchers estimate the starburst is cranking out stars at the breakneck pace of around 100 solar masses, or masses of our Sun, per year.

The prodigious energy output of this starburst in a decentralized location as revealed in the infrared has surprised the Spitzer researchers. The new observations go to show how the notion of a cosmic object's nature can change tremendously when viewed at different wavelengths of light. In this way, the shapes and dynamics of distant, harder-to-study galactic mergers could turn out to be a good deal more complex than current observations over a narrow range of wavelengths imply.

"Most of the far-infrared emission in II Zw 096, and hence most of the power, is coming from a region that is not associated with the centers of the merging galaxies," Inami explains. "This suggests that the appearances and interactions of distant, early galaxies during epochs when mergers were much more common than today in the Universe might be more complicated than we think."

A fleeting, perhaps prophetic vista?

In galaxy mergers, individual stars rarely slam into one another because of the vast distances separating them; even in the comparatively crowded central hubs of spiral galaxies, trillions of kilometers still often yawn between the stars.

But giant, diffuse clouds of gas and dust in galaxies do crash together -- passing through each other somewhat like ocean waves -- and in turn spur the gravitational collapse of dense pockets of matter into new stars. These young, hot stars shine intensely in the energetic ultraviolet part of the spectrum. In the case of II Zw 096, however, a thick shroud of gas and dust still surrounds this stellar brood. The blanket of material absorbs the stars' light and re-radiates it in the lower-energy, infrared wavelengths that gleam clear through the dust to Spitzer's camera.

Astronomers were lucky to capture this transient phase in the evolution of the starburst and of the daughter galaxy that will eventually coalesce out of the collision. "Spitzer has allowed us to see the fireworks before all the gas and dust has cleared away, giving us a preview of the exciting new galaxy being built under the blanket," Inami says.

Merging galaxies such as II Zw 096 also offer a sneak peek at the fate of our Milky Way in some 4.5 billion years when it is expected to plow into its nearest large galactic neighbor, the Andromeda Galaxy. Off-nuclear starbursts such as that in II Zw 096 and the Antennae Galaxy could occur in the vicinity of our Solar System, perhaps, which is located about two-thirds of the way out from the Milky Way's glowing, bulging center.

"This kind of dramatic thing happening in II Zw 096 could happen to the Milky Way and Andromeda when they meet in the far future," says Inami.

Crown Suggests Queen Arsinoë II Ruled Ancient Egypt as Female Pharaoh

A unique queen's crown with ancient symbols combined with a new method of studying status in Egyptian reliefs forms the basis for a re-interpretation of historical developments in Egypt in the period following the death of Alexander the Great. A thesis from the University of Gothenburg (Sweden) argues that Queen Arsinoë II ruled ancient Egypt as a female pharaoh, predating Cleopatra by 200 years.

Researchers are largely agreed on Queen Arsinoë II's importance from the day that she was deified. She was put on a level with the ancient goddesses Isis and Hathor, and was still respected and honoured 200 years after her death when her better-known descendant Cleopatra wore the same crown. But the reasons behind Arsinoë's huge influence have been interpreted in many different ways.

Maria Nilsson has studied her historical importance by interpreting her personal crown and its ancient symbols. The crown, which has never been found but is depicted on statues and Egyptian reliefs, was created with the help of the powerful Egyptian priesthood to symbolise the qualities of the queen. The thesis questions the traditional royal line which excludes female regents, and defies some researchers' attempts to minimise Arsinoë's importance while she was still alive.

"My conclusion instead is that Arsinoë was a female pharaoh and high priestess who was equal to and ruled jointly with her brother and husband, and that she was deified during her actual lifetime," says Nilsson. "It was this combination of religion and politics that was behind her long-lived influence."

But it was not only Cleopatra who wanted to re-use Arsinoë's important and symbolic crown. Male descendants -- all named Ptolemy -- used her crown as a template when creating a new crown which they gave to the goddess Hathor to honour the domestic priesthood and so win its support when Egypt was gripped by civil war.

The thesis is clearly structured around the crown and includes its wider context in the reliefs. Nilsson paints an all-round picture of the queen, how she dressed, the gods she was depicted with, the titles she was given, and so on.

The source material comes from Egypt and can be used as a basis for understanding the country's political and religious development. At the same time, Nilsson paves the way for future studies of Egyptian crowns as symbols of power and status, and of the development of art in a more general sense.

"The creation of Queen Arsinoë's crown was just the beginning," she says.

Dream Themes Reach Across Cultures

Afraid to share your dreams with others because you think you are alone? Chances are, if you have dreamed it, others have too. But do you have these dreams regularly?

This is what Calvin Kai-Ching Yu wanted to explore in a new study published in the November issue of Dreaming. He set out to analyze not only what dreams are most common, but what dreams recur regularly.

Yu reviews interesting findings from past studies and performs his own study to measure dream prevalence (what percent of people have ever had a dream), dream recurrence (what percent have had the dream more than three times in their life), and dream regularity (what percent have had the dream at least several times a year).

First up: the broad basics of dreams.

Dreams can transcend cultural differences. Past researchers have found that the most common dream themes were the same across different ethnic groups.

The most common? Being chased. Teeth falling out, losing control of a vehicle, flying and not being able to find a toilet make up about half of the most commonly recurring dream themes.

But dreams also have a darker side.

Yu cites a prior study that compared dream themes to psychosis. Traits common in psychotic and schizophrenic patients, such as delusions of grandiosity, persecution and religion, are very common in dreams. In fact, delusions such as "being tracked" and "becoming a celebrity" occurred more prevalently than common dream motifs such as "teeth falling out" and the classic "being nude."

Next, Yu designed his own study on a slightly different aspect of dreams: regularity. What type of dreams do we repeatedly have night after night?

Over 600 participants joined the study, conducted in Hong Kong. They were given a questionnaire which included 78 dream themes. Respondents then answered if they had never dreamed of the subject or if they had dreamed of it only once or twice, three times or more, several times a year or once a month or more.

So what dreams did participants revisit the most often?

The age old school/teacher/studying trope ranked number one. Not only had over 80 percent ever had a dream on that subject, but also over 50 percent said they dreamed about it regularly. Over half of the sample also repeatedly dreamed of "searching for a certain place" and "falling."

Some of the more surprising findings? "Eating delicious foods" was the fifth most regularly dreamed theme, higher ranked than flying or being chased. Perhaps dieters are seeking out their shunned treats in regular nightly escapes.

Most interestingly, the study found that dream prevalence, recurrence and regularity do not always correspond. For example, 68 percent of respondents dreamed "of being a child again," but hardly any have that dream repeatedly.

On the contrary, most had never dreamed of being physically attacked, but those who had were regularly dreaming of it. Likewise, "teeth falling out" rated significantly higher on regularity than on prevalence or recurrence. Ouch.

Back to the delusions. While most people wouldn't want to admit experiencing delusions in their waking lives, delusions in dreams were very common. Yu's study found six of the top 20 regular dream themes were delusions. Erotomania, or believing a famous person is in love with you, was one of the most common. One half of participants had dreamt of having a love affair with a celebrity. Romance trumps sex here, because only 22 percent dreamed of having a sexual relationship with a celebrity.

Glowing Trees To Replace Glowing Lamps

* Gold, sea-urchin-shaped nanoparticles make plant leaves glow.
* Treated trees could replace electric lights to illuminate city streets.
* Tree-lit streets likely years away.

The golden glow of street lights could soon be replaced by the green fluorescence of tree leaves. Scientists from the Academia Sinica and the National Cheng Kung University in Taipei and Tainan have implanted glowing, sea urchin shaped gold nanoparticles, known as bio light emitting diodes, or bio LEDs, inside the leaves of a plant.

The new nanoparticles could replace the electricity powered street light with biologically powered light that removes CO2 from the atmosphere 24 hours a days.

"In the future, bio-LED could be used to make roadside trees luminescent at night," said Yen-Hsun Su in an interview with Chemistry World. "This will save energy and absorb CO2 as the bio-LED luminescence will cause the chloroplast to conduct photosynthesis."

The gold, sea urchin shaped nanoparticles are the key to turning a material that normal absorbs light into one that emits it.

Chlorophyll, the photosynthetic pigment that gives leaves their characteristic green color, is widely known for its ability to absorb certain wavelengths of light. However, under certain circumstances, such as being exposed to violet light, chlorophyll can also produce a light of its own. When exposed to light with a wavelengths of about 400 nanometers the normally green colored chlorophyll glows red.

Violet light is hard to come by though, especially at night, when glowing leaves would be useful to drivers and pedestrians. The scientists needed a source of violet light, and found it in the gold nanoparticles.

When shorter wavelengths of light, invisible to the human eye, hit the gold nanoparticles, they get excited and start to glow violet. That violet light strikes the nearby chlorophyll molecules, excites them, and the chlorophyll then produces the red light.

The scientists, who published their work on bio LEDs in the journal Nanoscale, hope that that trees treated with the gold nanoparticles would produce enough light that they could replace electric or gas street lights.

For now however, the effect is limited to the scientist's test subject, an aquatic plant known as Bacopa caroliniana. Expanding to terrestrial plants, the kind that line streets, should be possible, said Krishanu Ray, a scientist at the University of Maryland, with some additional work.

"They certainly could be used as street lights," said Ray. "But that's a long way away."

Secret Insignias From the ‘Black Ops’ World

Whatever impulse drives soldiers, sailors, airmen and marines to commemorate their units with insanely random, over-the-top, or awesomely bad patches, we say: Cultivate it.

Trevor Paglen, a bi-coastal artist and author based in Oakland and New York City, brought bad military patches to new heights of glory with his 2007 book I Could Tell You But Then You Would Have to Be Destroyed by Me. It's a collection of more than 100 insignias from the most secret of military units. The following are some of the best patches from a new edition of his book coming out.

Paglen's first book got coverage in a lot of newspapers and on The Colbert Report. So, any satellite operator or drone pilot wanting to immortalize their units would send along a patch for the next edition.

That didn't always thrill higher-ups. "I heard that one commander started a little witch hunt to find out who'd leaked a space-related patch to me," Paglen says. "None of these patches are 'classified' per se, but some were produced with an informal understanding that they wouldn’t be made public. I hope nobody got into trouble."

Paglen knows about some white-whale patches that he hasn't gotten his hands on yet. Know anything about Ibis Dawn, Scarecrow, Sundowner, or something that says Invisus cum libertas et iustitia omnibus? "If you have one of these," Paglen says, "I'd love to trade something cool for it, or even get a nice scan." Until he puts out yet another edition, these 10 designs have to stand as a high-water mark in awesomely bad military patches.

Above:
Like a Space-Phoenix From Hell

The Latin phrase below the Phoenix translates to "The Devil You Know." That's the rationale behind the spy-satellite operators at the National Reconnaissance Office, who peer into the workings of foreign military arsenals from hundreds of miles into space.

This patch, from National Reconnaissance Office Launch 49, puts a bold face on a failure: the Future Imagery Architecture, a $10-billion disaster in the guise of a satellite able to peer through heavy cloud cover. The end of Future Imagery Architecture meant that NRO had to continue with its KH "Keyhole" satellite family, many of which the United States uses to spy on Russian nukes. Launch 49 of the KH-11 series supposedly used spare parts from Future Imagery Architecture -- hence the Phoenix design.

Image: Courtesy Trevor Paglen




Special Projects Flight Test Squadron

No one patch may cobble together as many symbols as this one does. "Rat 55" is the call sign for pilots flying the T-43A, a radar testbed ("Rat," get it?) with an Air Force serial number ending in 55.

The rat's holding a pair of radar devices, one stretched outward and one near its butt, "both of which recall the radome configuration" of the plane. Other flight-test operators for classified aircraft wear patches with wizardy features, so presumably that's what's up with the rat's hat.



Confirmed: The Air Force Totally Hides Aliens From Us

You don't know how many Freedom of Information Act requests we've filed in the hope of finding the Alien Technology Exploitation Division, the intrepid souls who'll soon announce a sources-sought contract to develop the Hyperspace Blaster. Alas, they don't exist.

A former officer at Air Force Space Command tells Paglen that he and his friends had the patches made at their own expense after getting endlessly ribbed for working in a secure vault "where they kept the alien bodies." They wore them on their flight suits for months before a one-star general asked where he could get one of his own.


Special Projects Flight-Test Squadron

Welcome to Area 51.

Out in the Nevada desert, in a place called Groom Lake, the Air Force's most secretive organization tests its advanced prototypes. Supposedly, Lockheed's F-117A Nighthawk stealth plane went through Groom Lake's test facilities -- one of many flown by the Special Projects Flight Test Squadron, whose patch this is.

The diamond shape in the center of the undated patch "may refer to early designs of stealth aircraft," Paglen writes. Those planes are parked next to the dismembered Martians.



Space Spies Are Ready to Breach Your Borders

Paglen won't be able to find the origins of every patch he comes across. But rarely is a mystery more appropriate than in the case of the Sensor Hunters, whoever they are. Illustrated by one of MAD Magazine's spies, their brief(cases) include spying on the entire world, with swaggering disregard for nations' claims to control their own internal affairs.

The twinkling stars probably suggest these guys have something to do with space, but all Paglen writes is that they "devoted to reconnaissance and intelligence operations."



I Want to Believe (in the Navy's Communications Network)

The Navy uses a system of Boeing-designed space satellites to keep mariners connected with each other and home base while they're out at sea. The system is known as the Ultra-High Frequency Follow-On program.

If you squint enough, that kinda-sorta-maybe abbreviates to UFO. Naturally, some wise-cracking sailor -- Paglen doesn't specify whom -- had the idea to make this X-Files-inspired patch.


The More Secretive the Drone, the More Psychedelic the Patch

Groom Lake doesn't just house cutting-edge piloted planes. It's also home to the Desert Prowler, a Lockheed-designed drone shrouded in mystery since its 2005 launch -- and, perhaps, related to a different secret drone, the RQ-170 Sentinel aloft over Kandahar.

And since its remote pilots and crew can't exactly flaunt their involvement with the program, their patches will have to suffice. The Roman numerals for 9 and 11 partially bound the badge -- subtle! -- and the rainbow-emanating eye has a lightning bolt through it, suggesting that the drone is armed and ready to rain vengeance for 9/11 on presumed Kandahari insurgents. Wild guess: The lightning-bolted Omega in the thought balloon indicates the drone is dreaming of a violent end to its targets.

Astronomers Find 'Rosetta Stone' for T-Dwarf Stars

An international team of astronomers have discovered a unique and exotic star system with a very cool methane-rich (or T-) dwarf star and a 'dying' white dwarf stellar remnant in orbit around each other. The system is a 'Rosetta Stone' for T-dwarf stars, giving scientists the first good handle on their mass and age.
The team, led by Dr Avril Day-Jones of the Universidad de Chile and including Dr David Pinfield of the University of Hertfordshire as well as astronomers from the University of Montreal, publish their results in the journal Monthly Notices of the Royal Astronomical Society.

The system is the first of its type to be found. The two stars are low in mass and have a weak mutual gravitational attraction as they are separated by about a quarter of a light year or 2.5 trillion km (to put this in context Neptune is only 4.5 billion km from the Sun). Despite the frailty of the system it has stayed together for billions of years, but its stars are cooling down to a dark demise.

Methane dwarfs are on the star / planet boundary and are about the size of the giant planet Jupiter. They have temperatures of less than 1000 degrees Celsius (in comparison the Sun's surface is at 5500 degrees Celsius). Methane is a fragile molecule destroyed at warmer temperatures, so is only seen in very cool stars and objects like Jupiter. Neither giant planets nor T-dwarf stars are hot enough for the hydrogen fusion that powers the Sun to take place, meaning that they simply cool and fade over time.

White dwarfs are the end state of stars similar to and including the Sun. Once such stars have exhausted the available nuclear fuel in their cores, they expel most of their outer layers into space forming a remnant planetary nebula and leaving behind a hot, but cooling core or white dwarf about the size of the Earth. For our Sun this process will begin about 5 billion years in the future.

In the newly-discovered binary, the remnant nebula has long since dissipated and all that is left is the cooling white dwarf and methane dwarf pair.

Dr Day-Jones puts this in context, commenting, "In about 6 billion years' time, when our Sun 'dies' and becomes a white dwarf itself, the stars in the newly-discovered system will have changed dramatically. The methane dwarf will have cooled to around room temperature, and the white dwarf will have cooled to 2700 Celsius or the temperature of the methane dwarf at the start of its life."

This binary is providing a crucial test of the physics of ultra-cool (temperatures less than 1000 degrees Celsius) stellar atmospheres because the white dwarf lets us establish the age of both objects. It calibrates properties of the methane dwarf such as its mass, making it a kind of 'Rosetta Stone' for similar stars with complex, hazy ultra-cool atmospheres.

The methane dwarf was identified in the UKIRT Infrared Deep Sky Survey (UKIDSS) as part of a project to identify the coolest objects in the galaxy. Its temperature and spectrum were measured by the Gemini North Telescope in Hawaii.

The team then found that the methane dwarf shares its motion across the sky with a nearby blue object catalogued as LSPM 1459+0857. They studied the blue object using the world's largest optical telescope, the European Southern Observatory's Very Large Telescope (VLT) in Chile. The new VLT observations revealed the blue object to be a cool white dwarf and companion to the methane dwarf. The objects were thus re-christened LSPM 1459+0857 A and B.

The two stars are today separated by at least 2.5 trillion km, but would have been closer in the past before the white dwarf was formed. Once the star that formed the white dwarf reached the end of its life and expelled its outer layers, the loss of mass weakened the gravitational pull between the stars, causing the methane dwarf to spiral outwards to create the gravitationally fragile system that we see today. But the current age of the white dwarf indicates that this system has survived for several billion years. So the new discovery shows that despite their fragility, such binaries are able to remain united even as they move through the maelstrom of the disc of our Galaxy.

"Binary systems like this provide vital information and allow us to better understand ultra-cool atmospheres and the very low-mass dwarfs and planets they enshroud" says Dr Pinfield. "The fact that these binaries survive intact for billions of years means that we could find many more lurking out there in the future."