Dec 28, 2013

Genetic Clue to Fighting New Strains of Flu

Researchers at the University of Melbourne have discovered a genetic marker that can accurately predict which patients will experience more severe disease in a new strain of influenza (H7N9) currently found in China.

Published in the journal Proceedings of the National Academy of Sciences, senior author, Associate Professor Katherine Kedzierska from the Department of Microbiology and Immunology said that being able to predict which patients will be more susceptible to the emerging influenza strain, will allow clinicians to better manage an early intervention strategy.

"By using genetic markers to blood and lung samples, we have discovered that there are certain indicators that signal increased susceptibility to this influenza. Higher than normal levels of cytokines, driven by a genetic variant of a protein called IFITM3, tells us that the severe disease is likely," she said.

"We call this a Cytokine Storm and people with the defective genetic variant of the protein IFITM3 are more likely to succumb to severe influenza infection.

Professor Peter Doherty, AC, Laureate Professor and a lead author of the study from the University of Melbourne said predicting how influenza works in individuals has implications for the management of disease and the resources on our health system.

"We are exploring how genetic sequencing and early identification can allow us to intervene in treating patients before they become too unwell. As new cases of influenza emerge in the Northern Hemisphere, we try to keep a season ahead and prepare to protect the most vulnerable in our community," he said.

Read more at Science Daily

Antioxidant Drug Knocks Down Multiple Sclerosis-Like Disease in Mice

Researchers at Oregon Health & Science University have discovered that an antioxidant designed by scientists more than a dozen years ago to fight damage within human cells significantly helps symptoms in mice that have a multiple sclerosis-like disease.

The antioxidant -- called MitoQ -- has shown some promise in fighting neurodegenerative diseases. But this is the first time it has been shown to significantly reverse an MS-like disease in an animal.

The discovery could lead to an entirely new way to treat multiple sclerosis, which affects more than 2.3 million people worldwide.

Multiple sclerosis occurs when the body's immune system attacks the myelin, or the protective sheath, surrounding nerve fibers of the central nervous system. Some underlying nerve fibers are destroyed. Resulting symptoms can include blurred vision and blindness, loss of balance, slurred speech, tremors, numbness and problems with memory and concentration.

The antioxidant research was published in the December edition of Biochimica et Biophysica Acta Molecular Basis of Disease. The research team was led by P. Hemachandra Reddy, Ph.D., an associate scientist in the Division of Neuroscience at OHSU's Oregon National Primate Research Center.

To conduct their study, the researchers induced mice to contract a disease called experimental autoimmune encephalomyelitis, or EAE, which is very similar to MS in humans. They separated mice into four groups: a group with EAE only; a group that was given the EAE, then treated with the MitoQ; a third group that was given the MitoQ first, then given the EAE; and a fourth "control" group of mice without EAE and without any other treatment.

After 14 days, the EAE mice that had been treated with the MitoQ exhibited reduced inflammatory markers and increased neuronal activity in the spinal cord -- an affected brain region in MS -- that showed their EAE symptoms were being improved by the treatment. The mice also showed reduced loss of axons, or nerve fibers and reduced neurological disabilities associated with the EAE. The mice that had been pre-treated with the MitoQ showed the least problems. The mice that had been treated with MitoQ after EAE also showed many fewer problems than mice who were just induced to get the EAE and then given no treatment.

"The MitoQ also significantly reduced inflammation of the neurons and reduced demyelination," Reddy said. "These results are really exciting. This could be a new front in the fight against MS."

Even if the treatment continues to show promise, testing in humans would be years away. The next steps for Reddy's team will be to understand the mechanisms of MitoQ neuroprotection in different regions of the brain, and how MitoQ protects mitochondria within the brain cells of the EAE mice. Mitochondria, components within all human cells, convert energy into forms that are usable by the cell.

There is a built-in advantage with MitoQ. Unlike many new drugs, MitoQ has been tested for safety in numerous clinical trails with humans. Since its development in the late 1990s, researchers have tested MitoQ's ability to decrease oxidative damage in mitochondria.

Read more at Science Daily

Dec 27, 2013

Building a Better Malaria Vaccine: Mixing the Right Cocktail

A safe and effective malaria vaccine is high on the wish list of most people concerned with global health. Results published on December 26 in PLOS Pathogens suggest how a leading vaccine candidate could be vastly improved.

The study, led by Sheetij Dutta, from the Walter Reed Army Institute of Research, USA, and colleagues, focused on a protein called AMA1 needed by the Plasmodium falciparum parasite to invade blood cells and cause disease. Study results suggest that a cocktail of AMA1 proteins from only a few different strains can overcome major limitations of an earlier designed version of AMA1-based vaccines.

The challenge with the malaria parasite in general and its AMA1 surface protein in particular is that both exist as multiple strains. Using AMA1 in a vaccine readies the human immune system for subsequent encounters with the parasite, but when such a vaccine was previously tested in humans, it was effective mostly against one particular P. falciparum strain. To explore the potential for a more broadly protective vaccine, the scientists tested different cocktails of AMA1 from different parasite strains for their ability to elicit a diverse range of antibodies that are active in parasite inhibition assays. They confirmed that a cocktail of AMA1 proteins from three different parasite strains was better than one or two, and one they call Quadvax, which contained AMA1 proteins derived from four different strains, led to an antibody response that was broader than the sum of strain-specific antibodies elicited by the four individual strains. Moreover, Quadvax-elicited antibodies inhibited a range of parasites, including many strains that were different from those in the Quadvax mix. In different laboratory tests, Quadvax-induced antibodies inhibited the growth of 26 different parasite strains, and the scientists suggest that "the combination of four AMA1 variants in Quadvax may be sufficient to overcome global AMA1 diversity."

Besides varying a lot from strain to strain, AMA1 also contains less variable (conserved) exposed parts (so-called epitopes) on its surface. The researchers found that vaccination with Quadvax yielded not only antibodies against the variable epitopes, but also against more conserved epitopes of the AMA1 protein. Such antibodies were not seen when using individual strains for immunization, but Quadvax appeared to enhance the immunogenicity -- the ability to provoke an antibody response -- of these conserved parts of the protein. Since the epitopes are identical across strains, the resulting antibodies are broadly active rather than strain-specific.

The scientists conclude "we had set out to study broadening of antibody responses achieved by mixing AMA1 proteins and were surprised and delighted to find not only greater variety of strain-specific antibodies but also increased antibodies against conserved epitopes were induced by the Quadvax. Perhaps even more exciting, when mixed, combinations of these antibodies were synergistic in their broad inhibition of many parasite strains. Novel conserved epitopes described here can be targets for further improvement of the vaccine. Most importantly, our data strongly supports continued efforts to develop a blood stage vaccine against malaria."

Read more at Science Daily

‘Pufferfish on Steroids’ Gets as Big as a Truck

If Finding Nemo taught us anything, it’s that we may as well rename the clownfish “that Nemo fish.” Beyond that, it’s a great study in marine ecology: Nemo’s rescue party casts off from the safety of the reef into the perilous open ocean, where one must be fast, inconspicuous or untouchably enormous to survive. Our heroes are none of these, and thus hijinks ensue.

Millions of years ago a small fish embarked on its own Nemo-esque voyage, abandoning reefs in favor of open ocean. Over the millennia it lost its tail and grew absolutely immense; today it can reach more than 10 feet in length and 5,000 pounds, thus putting itself beyond threat of all but the mightiest predators.

The bizarre ocean sunfish is the world’s biggest bony fish. The Germans call it “the swimming head,” the Chinese “the toppled car fish,” and taxonomists Mola mola — which, ironically enough for something that floats, is Latin for “millstone.” And unlike Nemo’s compatriots, it is beautifully adapted to the high seas.

The ocean sunfish’s streamlined body allows it to slice easily through the water and sneak up on photographers and pretend that it’s the one who’s surprised.
Mola mola is without doubt the planet’s most oddly proportioned fish. In place of a tail is a structure made of migrated dorsal and anal fin rays known as a clavus, which serves as a rudder. “They look like they’d be a silly design,” said marine biologist and National Geographic explorer Tierney Thys, “but they’re actually very efficient, and one of the few examples of an underwater animal that’s actually flying through the water with lift-based design.”

While most fish swing their tails back and forth to swim, Mola mola has a fused and greatly shortened backbone and relies solely on its towering fins for power. With such a conspicuously flat body, it deftly slices through the water, wide-eyed and mouth agape like a perpetually surprised saw blade.

“They just seem like this conundrum,” Thys said. “Why lose your tail and head off into the open sea? Well, that’s all explained by looking at their ancestry. They come from a group of fishes related to pufferfish and porcupine fish. Essentially they’re just a pufferfish on steroids. And if you look at the way pufferfish and porcupine fish live their lives, they’re built for comfort, not for speed.”

This ancestry is betrayed by the ocean sunfish’s tiny larvae, which develop the pufferfish’s characteristic spines before resorbing them as they mature, said Thys. These barbs help reduce predation — with an emphasis on reduce. Thys has found tuna with their stomachs packed full of sunfish larvae.

Again, the open ocean is an exceedingly difficult place to survive, especially for a young ‘un. Save for the occasional drifting clump of vegetation (or, increasingly, rafts of plastic), there isn’t a lick of cover for such larvae. So Mola mola subscribes to the spray-and-pray method of reproduction. It’s the fecundity record-holder, with a 4-footer observed releasing some 300 million eggs. Each egg is the size of a Times New Roman lowercase “o,” making the ocean for a short time read something like “oooooooooooooooooooo.” For a creature that can reach more than two tons, that’s astonishingly tiny. Indeed, the ocean sunfish also holds the record for vertebrate growth. That diminutive egg will grow in size 60 million times, the equivalent of a human child ballooning to the weight of six Titanics by adulthood.

This incredible growth requires incredible feeding, yet the ocean sunfish hunts one of the sea’s more low-calorie offerings: jellyfish. Your average moon jelly, for instance, packs about four calories per 3.5 ounces of mass. This might not seem worth it for the ocean sunfish, especially to those of you who have been stung by jellies. (I may as well take a moment to mention that you shouldn’t apply urine to a sting. That’s a myth started by some guy who’s probably pretty damn proud of himself at this point).

But Mola mola is well equipped for the abuse. “They’ve got really thick lips,” said Thys. “They’ve got very thick skin, like a hide, and they have a lot of mucus that covers their skin.” Its skin is composed of tiny plates with tiny spines, like those of the pufferfish. It is so rough and tough that an ocean sunfish struck by an Australian ship in 1998 wore the paint down to the metal as it stuck to the bow.

An ocean sunfish skeleton next to a descriptive plaque the creature is fond of carrying around in the wild.
The protection against stings continues right into its guts. The ocean sunfish has a very robust intestinal wall. “In Taiwan there’s a specialty dish called dragon intestines, and that’s made from the guts of Mola, because they’re very thick, tube-like intestines,” said Thys.

The ocean sunfish supplements its diet with all manner of other creatures, from squid to small fish to odd creatures called salps. It can dive to more than 3,000 feet in search of food; in the dark depths of the sea, it relies on large eyes connected to a brain that devotes an unusual amount of computational power to the optic nerve.

It’s on the surface, though, where the ocean sunfish puts on a show that gives it its name — the “sunfish” bit, not the “ocean” part. Curiously, it will turn on its side and bask. It’s a measure to remove parasites, of which Mola mola hosts some 40 genera. By laying on its side, the sunfish presents a buffet to seagulls that pick parasites off its skin. “And then whenever you’re in the ocean and you come across anything floating, it attracts little fishes underneath it,” said Thys. “So by casting this shadow it could also attract little cleaner fishes to come up and eat parasites off them.”

UV rays also could be frying the parasites, said Thys. This may have the added bonus of thermally recharging the fish, which has been tracked during a dive experiencing temperatures falling from 68 degrees Fahrenheit to just 35 degrees. So, yes, the ocean sunfish gets its tan on. And yes, in case you were wondering, accordingly it’s fond of the Jersey Shore.

Read more at Wired Science

Bald Eagle Spotting: Top Spots

Forty years ago, the Endangered Species Act was signed into law by President Richard Nixon. The act’s authors sought to protect animals, plants and other wildlife from extinction caused by “economic growth and development untempered by adequate concern and conservation,” in the words of the Act.

One symbol of the United States, the bald eagle, provides an example of how a change to the economy saved an icon of North America.

DDT, or dichloro-diphenyl-trichloroethane, weakened eagle and other bird egg shells so much that the eggs would collapse under the mother. The chemical was introduced in the 1940s and already had decimated bird populations by the early 1960s.

In 1972, the U.S. Environmental Protection Agency banned the pesticide. The removal of DDT from the market allowed eagle eggs to regain their strength, and the raptors began a recovery.

Bald eagles soared off of the Endangered Species List in 2007. Although off the list, the birds are still protected by the Bald and Golden Eagle Protection Act, Migratory Bird Treaty Act and the Lacey Act, according to the U.S. Fish and Wildlife Service.

An eagle-watching trip could be a thrilling way to celebrate the 40th anniversary of the Endangered Species Act and the success of bald eagles.

From coast to coast, National Wildlife Refuges offer winter-long opportunities to observe the raptors, along with special events.

The USFWS presents a cross-country list of these eagle adventures in Maryland, Virginia, Illinois, Tennessee, Missouri, Oklahoma, Utah, California, Oregon and Washington. Here are a few highlights:

Maryland: Blackwater National Wildlife Refuge Eagle Festival March 15, 2014, from 9 a.m. to 4 p.m. The festival is a free way to see more than 200 eagles overwintering in the refuge, the largest population on the East Coast, north of Florida.

Read more at Discovery News

Nearby Failed Star Binary May Hide Alien World

Astronomers have spotted signs of a possible exoplanet in a nearby system of twin failed stars. If confirmed, the alien world would be one of the closest to our sun ever found.

Scientists only discovered the pair of failed stars, known as brown dwarfs, last year. At just 6.6 light-years from Earth, the pair is the third closest system to our sun. It's actually so close that "television transmissions from 2006 are now arriving there," Kevin Luhman, of Penn State's Center for Exoplanets and Habitable Worlds, noted when their discovery was first announced in June.

The brown dwarf system, which has been dubbed Luhman 16AB and is officially classified as WISE J104915.57-531906, is slightly more distant than Barnard's star, a red dwarf 6 light-years away that was first seen in 1916. Even closer to our sun is Alpha Centauri, whose two main stars form a binary pair about 4.4 light-years away. The alien planet Alpha Centauri Bb is known to orbit one of the stars in the Alpha Centauri system, and currently holds the title of closest exoplanet to our solar system.

The brown dwarfs were spotted in data from NASA's Wide-field Infrared Survey Explorer (WISE) spacecraft, which took about 1.8 million images of asteroids, stars and galaxies during its ambitious 13-month mission to scan the entire sky. Brown dwarfs are sometimes called failed stars because they are bigger than planets but don't enough mass to kick-off nuclear fusion at their core.

Henri Boffin of the European Southern Observatory (ESO) led a team of astronomers seeking to learn more about our newfound dim neighbors. The group used the very sensitive FORS2 instrument on ESO's Very Large Telescope at Paranal in Chile to take astrometric measurements of the objects during a two-month observation campaign from April to June 2013. (Astrometry involves tracking the precise motions of a star in the sky.)

"We have been able to measure the positions of these two objects with a precision of a few milli-arcseconds," Boffin said in a statement. "That is like a person in Paris being able to measure the position of someone in New York with a precision of 10 centimeters."

The group discovered that both brown dwarfs in the system have a mass 30 to 50 times the mass of Jupiter. (By comparison, our sun's mass is about 1,000 Jupiter masses.) Because their mass is so low, they take about 20 years to complete one orbit around each other, the astronomers said.

Boffin's team also discovered slight disturbances in the orbits of these objects during their two-month observation period. They believe the tug of a third object, perhaps a planet around one of the two brown dwarfs, could be behind these slight variations.

"Further observations are required to confirm the existence of a planet," Boffin aid in a statement. "But it may well turn out that the closest brown dwarf binary system to the sun turns out to be a triple system!"

Read more at Discovery News

Dec 24, 2013

Happy Holidays

I wanted to take the time to wish all of you readers of A Magical Journey, happy holidays. Take this time and spenty it with family and loved ones even if you're an atheist. You don't have to be a theist to spend time with those you love or give gifts. Don't do anything stupid is my advice.

Happy Holidays
Danny at A magical Journey

Dec 23, 2013

Thousand-Year-Old Vineyards Discovered in Alava, Spain

Zaballa (Iruña de Oca) was a medieval settlement abandoned in the 15th century. The building of a manor monastery at the heart of it undermined the organisation of the village in the 10th century with the creation of a highly significant rent-seeking system; it was later turned into a veritable factory, a specialised estate in the hands of local lords who, under the auspices of the economic boom in towns like Vitoria-Gasteiz, tried to obtain the maximum profits possible. In the end, the "flight" of its settlers towards the towns caused it to be abandoned.

Today, it is archaeologists from the UPV/EHU-University of the Basque Country who are endeavouring to reconstruct and salvage our rural heritage by studying deserted settlements like Zaballa.

Zaballa is one of the more than 300 deserted settlements known in Alava-Araba; they are rural spaces abandoned in historical times but now being studied by the UPV/EHU's Cultural Heritage and Landscapes Research Group. Its director, Juan Antonio Quirós-Castillo, highlights the importance of Zaballa and Alavese sites in general, as they are part of one of the most importance archaeological records of the mediaeval era throughout northern Iberia, and on a par with few sites in Europe. "The important thing is not just their number, but that in the decade that we have been working on this project, extensive work has been done on nearly half a dozen of them, and work at other levels has been done on nearly a hundred."

A major site

Zaballa is also the first deserted settlement in Spain that has its own publication and is a major site. The most recent discoveries made there have been published in a special issue of the journal Quaternary International; among the discoveries, the authors stress that the terraced fields built in the 10th century -- still perfectly visible in the landscape -- were devoted to the intensive cultivation of vines. "Archaeo-botanical studies of seed remains found in the excavations and pollen studies have provided material evidence of the existence of vine cultivation in a relatively early period like the 10th century," explained Quirós. This evidence is also supported by the metal tools discovered and which had been destined for this very use, and the study of the agrarian spaces, "which owing to the nature of the crop spaces built and the agrarian practices developed, they are not compatible with cereal crops but they are with vines," he added.

This publication covers the geo-archaeological work conducted at Zaballa and Zornotegi (Salvatierra), another abandoned settlement in Alava, which became deserted in the 15th century and where the terraced fields were devoted to the cultivation of cereals.

These discoveries have been made possible by the use of archaeological excavation protocols, and geo-archaeological sampling and analysis, which are new in Spain and which have allowed the cultivated fields to be dated and the agrarian cycle to be studied. "It is not so much about excavating a site, but about excavating landscapes," explained Quirós. In other words, it is about abandoning the traditional concept of the site, understood as a monumental or monumentalised place, in order to get to know the context in which these places are located."

In comparison with Zaballa, "Zornoztegi has a completely different history," he pointed out. "Even though it was founded at more or less the same time, it is a much more egalitarian social community in which such significant social differences are not observed, and nor is the action of manorial powers which, in some way, undermined the balance of the community."

In Quirós' view, these microhistories constitute small windows into the past that allow one to analyse relatively complex historical processes directly, bottom upwards, "in other words, to see how the peasant community itself gradually adapts to the political and economic changes that take place in the medieval era and later."

What is more, the analytical study of these places of production allows one to abandon those more traditional points of view of history which "conceptualize the high medieval periods as a time of technical simplification, as a meagre period in economic terms, since they point to considerable social and economic complexity. Specifically, it has been possible in these studies to see that there are various important moments in the Basque Country, 5th to 6th centuries and 10th to 11th centuries, which were decisive in the construction of our landscapes."

Read more at Science Daily

Solitons in a Crystal: New Light Source Could Serve in Geo-Navigation, Search for Earth-Like Planets

Soliton water waves can travel several kilometers without any significant change in their shape or amplitude, as opposed to normal waves, which widen as they travel, and eventually disappear. Discovered over 150 years ago in water canals, solitons represent a surprising phenomenon of wave propagation and have been observed in natural phenomena including moving sand dunes and space plasmas. A unique aspect of solitons is that they can retain their shape because of non-linear and dispersive effects that stabilize the wave. Solitons can even occur as pulses of light that can propagate through a suitable transparent medium, e.g. an optical telecommunication fiber.

Publishing in Nature Photonics, EPFL scientists collaborating with the Russian Quantum Center and the M.V. Lomonosov Moscow State University have now discovered that so-called optical dissipative solitons can also exist in small millimeter-size optical resonators.

The optical resonators are crystals shaped to form a resonator that can guide a soliton light pulse on an endless circular path. When such a soliton light pulse circulates inside the resonator, a small fraction of it can be extracted every time the pulse completes one roundtrip.

The scientists at EPFL's Laboratory for Photonics and Quantum Measurement analyzed the extracted light pulses from the resonator and found them to be surprisingly short in duration; much shorter in fact than one millionth of one millionth of a second. Due to the small size of the optical resonator, the time between two extracted pulses is extremely short and the pulse rate very high.

Read more at Science Daily

Clues to How Plants Evolved to Cope With Cold

Researchers have found new clues to how plants evolved to withstand wintry weather. In a study to appear in the December 22 issue of the journal Nature, the team constructed an evolutionary tree of more than 32,000 species of flowering plants -- the largest time-scaled evolutionary tree to date. By combining their tree with freezing exposure records and leaf and stem data for thousands of species, the researchers were able to reconstruct how plants evolved to cope with cold as they spread across the globe. The results suggest that many plants acquired characteristics that helped them thrive in colder climates -- such as dying back to the roots in winter -- long before they first encountered freezing.

Fossil evidence and reconstructions of past climatic conditions suggest that early flowering plants lived in warm tropical environments, explained co-author Jeremy Beaulieu at the National Institute for Mathematical & Biological Synthesis (NIMBioS) at the University of Tennessee.

As plants spread to higher latitudes and elevations, they evolved in ways that helped them deal with cold conditions. Plants that live in the tundra, such as Arctic cinquefoil and three-toothed saxifrage, can withstand winter temperatures below minus 15 degrees Celsius.

Unlike animals, most plants can't move to escape the cold or generate heat to keep them warm. It's not so much the cold but the ice that poses problems for plants. For instance, freezing and thawing cause air bubbles to form in the plant's internal water transport system.

"Think about the air bubbles you see suspended in the ice cubes," said co-author Amy Zanne of the George Washington University. "If enough of these air bubbles come together as water thaws they can block the flow of water from the roots to the leaves and kill the plant."

The researchers identified three traits that help plants get around these problems.

Some plants, such as hickories and oaks, avoid freezing damage by dropping their leaves before the winter chill sets in -- effectively shutting off the flow of water between roots and leaves -- and growing new leaves and water transport cells when warmer weather returns.

Other plants, such as birches and poplars, also protect themselves by having narrower water transport cells, which makes the parts of the plant that deliver water less susceptible to blockage during freezing and thawing.

Still others die back to the ground in winter and re-sprout from their roots, or start growing as new plants from seeds when conditions are right.

To compile the plant trait data for their study, the researchers spent hundreds of hours scouring and merging multiple large plant databases containing tens of thousands of species, largely with the support of the National Evolutionary Synthesis Center in North Carolina and Macquarie University in Australia.

When they mapped their collected leaf and stem data onto their evolutionary tree for flowering plants, they found that many plants were well equipped for icy climates even before cold conditions hit.

Plants that die back to the ground in winter, for example, acquired the ability to die and come back when conditions improve long before they first experienced freezing. Similarly, species with narrow water transport cells acquired a finer circulatory system well before they confronted cold climates.

"This suggests that some other environmental pressure -- possibly drought -- caused these plants to evolve this way, and it happened to work really well for freezing tolerance too," said Zanne.

Read more at Science Daily

Night-Shining Clouds Come Early Over South Pole

Night-shining clouds started glowing high above Antarctica earlier than usual this year, observations from a NASA satellite show.

These rare types of wispy blue-white clouds are called noctilucent clouds, or NLCs. They form when water molecules freeze around "meteor smoke" close to the edge of space, typically about 50 to 53 miles (80 and 85 kilometers) above Earth's surface — so high that they can reflect light after the sun sets.

The phenomenon looks spectacular from the ground, but scientists also have watched these night-shining clouds from above with NASA's AIM (Aeronomy of Ice in the Mesosphere) satellite since 2007. Data from AIM indicate that noctilucent clouds started forming around the South Pole on Nov. 20 this year as a tiny spot of electric blue that quickly expanded to cover the entire frozen continent, as this NASA video shows.

AIM's observations over the past few years helped scientists discover a key ingredient in night-shining clouds: "smoke" from meteoroids that bombard Earth's atmosphere. The falling space rocks leave behind a cloud of tiny particles that hovers about 43 to 62 miles (70 to 100 kilometers) above the ground.

Summer is primetime for noctilucent clouds. Because of global wind and humidity patterns, more water molecules are lifted up from the atmosphere during summer. It's also the season when the upper atmosphere is coldest, meaning more water vapor condenses into tiny ice crystals that latch onto the dust particles of disintegrated meteoroids, according to NASA. Accordingly, noctilucent clouds typically flare up over the South Pole from November to February (summer in the Southern Hemisphere), and then shift to the North Pole from May to August.

In all the years that AIM has been observing the clouds, only the 2009 noctilucent season got off to an earlier start in the South Pole, according to NASA. The 2013 season above the North Pole also started quite early (around May 13).

Read more at Discovery News

Dec 22, 2013

Researchers Grow Liquid Crystal 'Flowers' That Can Be Used as Lenses

A team of material scientists, chemical engineers and physicists from the University of Pennsylvania has made another advance in their effort to use liquid crystals as a medium for assembling structures.

In their earlier studies, the team produced patterns of "defects," useful disruptions in the repeating patterns found in liquid crystals, in nanoscale grids and rings. The new study adds a more complex pattern out of an even simpler template: a three-dimensional array in the shape of a flower.

And because the petals of this "flower" are made of transparent liquid crystal and radiate out in a circle from a central point, the ensemble resembles a compound eye and can thus be used as a lens.

The team consists of Randall Kamien, professor in the School of Arts and Sciences' Department of Physics and Astronomy; Kathleen Stebe, the School of Engineering and Applied Science's deputy dean for research and professor in Chemical and Biomolecular Engineering and Shu Yang, professor in Engineering's departments of Materials Science and Engineering and Chemical and Biomolecular Engineering. Members of their labs also contributed to the new study, including lead author Daniel Beller, Mohamed Gharbi and Apiradee Honglawan.

Their work was published in Physical Review X.

The researchers' ongoing work with liquid crystals is an example of a growing field of nanotechnology known as "directed assembly," in which scientists and engineers aim to manufacture structures on the smallest scales without having to individually manipulate each component. Rather, they set out precisely defined starting conditions and let the physics and chemistry that govern those components do the rest.

The starting conditions in the researchers previous experiments were templates consisting of tiny posts. In one of their studies, they showed that changing the size, shape or spacing of these posts would result in corresponding changes in the patterns of defects on the surface of the liquid crystal resting on top of them. In another experiment, they showed they could make a "hula hoop" of defects around individual posts, which would then act as a second template for a ring of defects at the surface.

In their latest work, the researchers used a much simpler cue.

"Before we were growing these liquid crystals on something like a trellis, a template with precisely ordered features," Kamien said. "Here, we're just planting a seed."

The seed, in this case, were silica beads -- essentially, polished grains of sand. Planted at the top of a pool of liquid crystal flower-like patterns of defects grow around each bead.

The key difference between the template in this experiment and ones in the research team's earlier work was the shape of the interface between the template and the liquid crystal.

In their experiment that generated grid patterns of defects, those patterns stemmed from cues generated by the templates' microposts. Domains of elastic energy originated on the flat tops and edges of these posts and travelled up the liquid crystal's layers, culminating in defects. Using a bead instead of a post, as the researchers did in their latest experiment, makes it so that the interface is no longer flat.

"Not only is the interface at an angle, it's an angle that keeps changing," Kamien said. "The way the liquid crystal responds to that is that it makes these petal-like shapes at smaller and smaller sizes, trying to match the angle of the bead until everything is flat."

Surface tension on the bead also makes it so these petals are arranged in a tiered, convex fashion. And because the liquid crystal can interact with light, the entire assembly can function as a lens, focusing light to a point underneath the bead.

Read more at Science Daily

Ancient Spider Rock Art Sparks Archaeological Mystery

Archaeologists have discovered a panel containing the only known example of spider rock art in Egypt and, it appears, the entire Old World.

The rock panel, now in two pieces, was found on the west wall of a shallow sandstone wadi, or valley, in the Kharga Oasis, located in Egypt's western desert about 108 miles (175 kilometers) west of Luxor. Facing east, and illuminated by the morning sun, the panel is a "very unusual" find, said Egyptologist Salima Ikram, a professor at the American University in Cairo who co-directs the North Kharga Oasis Survey Project.

The identification of the creatures as spiders is tentative and the date of it uncertain, Ikram told LiveScience in an email. Even so, based on other activity in the area, the rock art may date to about 4000 B.C. or earlier, which would put it well into prehistoric times, before Egypt was unified, noted Ikram, who detailed the finding in the most recent edition of the journal Sahara.

The main panel shows what appear to be a few spiders, with a "star" that's possibly meant to depict a web next to the spider on the far left. There are also comblike drawings that are more enigmatic; Ikram said they could be insects being trapped by the spiders, plants or even silken tubes spun by the spiders.

A piece of rock that appears to have been broken off the main panel depicts creatures drawn in a different style, their limbs not flexed, but ratherhave a flat appearance. This could be an attempt to portray a harvestman, an insect that looks like a spider.

The discovery leaves archaeologists with a mystery — why did people in the Kharga Oasis create rock art showing spiders, especially when no other examples are known to exist elsewhere in Egypt or, it appears, the entire Old World?

Why spiders?

There is little evidence the ancient Egyptians had much interest in drawing spiders. The only spider hieroglyphs that Ikram knows of are rare examples from "religious texts dealing with the so-called 'Opening of the Mouth' ritual, a rite that was performed on the mummy or a statue to restore its senses for use in the Hereafter."

The secret to solving the mystery may lie more in the western desert itself. Ikram consulted with Hisham El-Hennawy, an arachnologist who mentioned spiders called Argiope lobata living in the western and eastern deserts may have attracted the interest of ancient people. These spiders can be found "shaded and surviving, in the middle of their orb web under the burning sun at Noon," Ikram writes.

The idea of spiders bathing in the sun may hold religious significance to ancient people in the area. "This would combine the force of the sun and the ability of this solar creature to survive its heat successfully, and thus be worthy of reverence or totemic allegiance," she writes in the Sahara article.

Read more at Discovery News