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The blood-brain barrier in a live zebrafish embryo visualized

The blood-brain barrier in a live zebrafish embryo visualized | Amazing Science | Scoop.it

Dr. Jennifer Peters’ and Dr. Michael Taylor’s winning image of the blood-brain barrier in a live zebrafish embryo perfectly demonstrates the intersection of art and science that drives the Nikon Small World Competition.

 

The blood-brain barrier plays a critical role in neurological function and disease. Drs. Peters and Taylor, developed a transgenic zebrafish to visualize the development of this structure in a live specimen. By doing so, this model proves that not only can we image the blood-brain barrier, but we can also genetically and chemically dissect the signaling pathways that modulate the blood-brain barrier function and development.

 

To achieve this image, Peters and Taylor used a maximum intensity projection of a series of images acquired in the z plane. The images were first pseudo-colored with a rainbow palette based on depth so that the coloring scheme would be both visually appealing and provide spatial information. In doing so, Peters and Taylor captured an image that Peters says“not only captures the beauty of nature, but is also topical and biomedically relevant.”

 

Both Peters and Taylor have more than ten years of imaging experience. Peters is an imaging scientist in the St. Jude Children’s Research Hospital’s Light Microscopy Core Facility and Taylor is an Assistant Member in the Department of Chemical Biology and Therapeutics at St. Jude Children’s Research.

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Electronic chips heal themselves after destructive laser blast

Electronic chips heal themselves after destructive laser blast | Amazing Science | Scoop.it

It was incredible the first time the system kicked in and healed itself. It felt like we were witnessing the next step in the evolution of integrated circuits," says Ali Hajimiri, professor of electrical engineering at Caltech. "We had literally just blasted half the amplifier and vaporized many of its components, such as transistors, and it was able to recover to nearly its ideal performance."


Imagine if the chips in your phone or computer could fix themselves almost instantly from problems such as battery power loss and transistor failure. 

It might sound like the stuff of science fiction, but a team of engineers at the California Institute of Technology (Caltech), for the first time ever, has developed just such self-healing integrated chips. The team demonstrated this self-healing capability in tiny power amplifiers. The amplifiers are so small that 76 of the chips—including everything they need to self-heal—could fit on a single penny. 

 

In perhaps the most dramatic of their experiments, the team destroyed various parts of their chips by zapping them multiple times with a high-power laser, and then observed as the chips automatically developed a work-around in less than a second.

 

Until now, even a single fault has often rendered an integrated-circuit chip completely useless. The engineers wanted to give integrated-circuit chips a healing ability akin to that of our own immune system—something capable of detecting and quickly responding to any number of possible assaults in order to keep the larger system working optimally.

 

The power amplifier they devised employs a multitude of robust, on-chip sensors that monitor temperature, current, voltage, and power. The information from those sensors feeds into a custom-made application-specific integrated-circuit (ASIC) unit on the same chip, a central processor that acts as the “brain” of the system. The brain analyzes the amplifier’s overall performance and determines if it needs to adjust any of the system’s actuators—the changeable parts of the chip.

 

Interestingly, the chip’s brain does not operate based on algorithms that know how to respond to every possible scenario. Instead, it draws conclusions based on the aggregate response of the sensors.

“You tell the chip the results you want and let it figure out how to produce those results,” says Steven Bowers, a graduate student in Hajimiri’s lab and lead author of the new paper. “The challenge is that there are more than 100,000 transistors on each chip. We don’t know all of the different things that might go wrong, and we don’t need to.

 

World of possibilities: The team chose to demonstrate this self-healing capability first in a power amplifier for millimeter-wave frequencies. Such high-frequency integrated chips are at the cutting edge of research and are useful for next-generation communications, imaging, sensing, and radar applications.

 

By showing that the self-healing capability works well in such an advanced system, the researchers hope to show that the self-healing approach can be extended to virtually any other electronic system.

 

“Bringing this type of electronic immune system to integrated-circuit chips opens up a world of possibilities,” says Hajimiri. “It is truly a shift in the way we view circuits and their ability to operate independently. They can now both diagnose and fix their own problems without any human intervention, moving one step closer to indestructible circuits.”



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Josh C.'s comment, March 13, 2013 9:38 AM
Regenerating technology... we truly are going to have Halo be our future. Which would be awesome!
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Astronomers Discover Extremely Rare Type Ibn Supernova

Astronomers Discover Extremely Rare Type Ibn Supernova | Amazing Science | Scoop.it

An international team of astronomers has announced the discovery of a very rare Type Ibn supernova on the outskirts of a bright elliptical galaxy located about 780 million light-years away. “This supernova is one-of-a-kind. And it’s definitely in the wrong neighborhood,” said Dr. Nathan Sanders of the Harvard-Smithsonian Center for Astrophysics.


Based on the presence of helium and other features, the object, dubbed PS1-12sk, is classified as a very rare Type Ibn supernova – only the sixth such example found out of thousands of supernovae.

 

A new subclass of ‘Type Ibn,’ characterized by intermediate-width He I emission, has emerged since the discovery of the supernova SN 1999cq. Although the origin of these supernovae is unclear, the most likely cause seems to be the explosion of a massive star that previously ejected massive amounts of helium gas. That origin was supported by the fact that the five previous Type Ibn supernovae were all found in galaxies like the Milky Way that are actively forming stars.

 

PS1-12sk is different. The site of the explosion shows no signs of recent star formation, and a supernova from a massive star has never before been seen in a galaxy of this type.

 

“It could be that we simply got very lucky with this discovery. But luck favors the prepared,” said co-author Dr Alicia Soderberg, also of the Harvard-Smithsonian Center for Astrophysics.

 

The finding suggests that the host galaxy might be hiding a star factory, allowing it to form massive stars where none were expected. Alternatively, PS1-12sk might have an entirely different origin such as a collision of two white dwarfs, one of which was helium-rich.

 

“Is this a runaway star from another star formation site? Is it a very local bit of star formation? Is it a different way for such a supernova to occur? None of these seems very likely so we have a real puzzle,” said Dr. John Tonry of the University of Hawaii Institute for Astronomy.


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MIT: Extraterrestrial Life Found? Astrobiologists Find Ancient Fossils in a Sri Lankan Meteorite

MIT: Extraterrestrial Life Found? Astrobiologists Find Ancient Fossils in a Sri Lankan Meteorite | Amazing Science | Scoop.it
Algae-like structures inside a Sri Lankan meteorite are clear evidence of panspermia, the idea that life exists throughout the Universe, say astrobiologists

 

On 29 December 2012, a fireball lit up the early evening skies over the Sri Lankan province of Polonnaruwa. Hot, sparkling fragments of the fireball rained down across the countryside and witnesses reported the strong odour of tar or asphalt. Over the next few days, the local police gathered numerous examples of these stones and sent them to the Sri Lankan Medical Research Institute of the Ministry of Health in Colombo. After noticing curious features inside these stones, officials forwarded the samples to a team of astrobiologists at Cardiff University in the UK for further analysis. The results of these tests, which the Cardiff team reveal today, are extraordinary.  They say the stones contain fossilised biological structures fused into the rock matrix and that their tests clearly rule out the possibility of terrestrial contamination.

 

In total, the Jamie Wallis at Cardiff University and a few buddies received 628 stone fragments collected from rice fields in the region. However, they were able to clearly identify only three as possible meteorites. The general properties of these three stones immediately mark them out as unusual. One stone, for example, had a density of less than 1 gram per cubic centimetre, less than all known carbonaceous meteorites. It had a partially fused crust, good evidence of atmospheric heating, a carbon content of up to 4 per cent and contained an abundance of organic compounds with a high molecular weight, which is not unknown in meteorites. On this evidence, Wallis and co think the fireball was probably a small comet.

 

The most startling claims, however, are based on electron microscope images of structures within the stones (see above). Wallis and co say that one image shows a complex, thick-walled, carbon-rich microfossil about 100 micrometres across that bares similarities with a group of largely extinct marine dinoflagellate algae.

 

They say another image shows well-preserved flagella that are 2 micrometres in diameter and 100 micrometres long. By terrestrial standards, that’s extremely long and thin, which Wallis and co interpret as evidence of formation in a low-gravity, low-pressure environment.

 

Wallis and co also measured the abundance of various elements in the samples to determine their origin. They say that low levels of nitrogen in particular rule out the possibility of contamination by modern organisms which would have a much higher nitrogen content. The fact that these samples are also buried within the rock matrix is further evidence, they say.

 

Wallis and co are convinced that the lines of evidence they have gathered are powerful and persuasive. “This provides clear and convincing evidence that these obviously ancient remains of extinct marine algae found embedded in the Polonnaruwa meteorite are indigenous to the stones and not the result of post-arrival microbial contaminants,” they conclude.

 

There’s no question that a claim of this kind is likely to generate controversy. Critics have already pointed out that the stones could have been formed by lightning strikes on Earth although Wallis and co counter by saying there was no evidence of lightning at the time of the fireball and that in any case, the stones do not bear the usual characteristics of this kind of strike. What’s more, the temperatures generated by lightning would have destroyed any biological content.

 

Nevertheless, extraordinary claims require extraordinary evidence and Wallis and co will need to make their samples and evidence available to the scientific community for further study before the claims will be taken seriously. If the paper is taken at face value, one obvious question that arises is where these samples came from. Wallis and co have their own ideas: “The presence of fossilized biological structures provides compelling evidence in support of the theory of cometary panspermia first proposed over thirty years ago,” they say.

 

This is an idea put forward by Fred Hoyle and Chandra Wickramasinghe, the latter being a member of the team who has carried out this analysis. There are other explanations, of course. One is that the fireball was of terrestrial origin, a remnant of one of the many asteroid impacts in Earth’s history that that have ejected billions of tonnes of rock and water into space, presumably with biological material inside. Another is that the structures are not biological and have a different explanation. 

 

Either way, considerably more work will have to be done before the claims from this team can be broadly accepted. Exciting times ahead!

 

Original paper is here: Ref: http://arxiv.org/abs/1303.1845: The Polonnaruwa Meteorite: Oxygen isotope, Crystalline and Biological Composition

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Astronomers conduct first visualization of an extrasolar planetary system 128 light years away

Astronomers conduct first visualization of an extrasolar planetary system 128 light years away | Amazing Science | Scoop.it

Researchers have conducted a remote reconnaissance of a distant planetary system with a new telescope imaging system that sifts through the blinding light of stars. Using a suite of high-tech instrumentation and software called Project 1640, the scientists collected the first chemical fingerprints, or spectra, of this system's four red exoplanets, which orbit a star 128 light years away from Earth. A detailed description of the planets -- showing how drastically different they are from the known worlds in the universe.

 

"An image is worth a thousand words, but a spectrum is worth a million," said lead author Ben R. Oppenheimer, associate curator and chair of the Astrophysics Department at the American Museum of Natural History.

Oppenheimer is the principal investigator for Project 1640, which uses the Hale telescope at the Palomar Observatory in California. The project involves researchers from the California Institute of Technology, NASA's Jet Propulsion Laboratory, Cambridge University, New York University, and the Space Telescope Science Institute, in addition to Oppenheimer's team at the Museum.

 

The planets surrounding the star of this study, HR 8799, have been imaged in the past. But except for a partial measurement of the outermost planet in the system, the star's bright light overwhelmed previous attempts to study the planets with spectroscopy, a technique that splits the light from an object into its component colors -- as a prism spreads sunlight into a rainbow. Because every chemical, such as carbon dioxide, methane, or water, has a unique light signature in the spectrum, this technique is able to reveal the chemical composition of a planet's atmosphere.

 

"In the 19th century it was thought impossible to know the composition of stars, but the invention of astronomical spectroscopy has revealed detailed information about nearby stars and distant galaxies," said Charles Beichman, executive director of the NASA Exoplanet Science Institute at the California Institute of Technology. "Now, with Project 1640, we are beginning to turn this tool to the investigation of neighboring exoplanets to learn about the composition, temperature, and other characteristics of their atmospheres."

 

With this system, the researchers are the first to determine the spectra of all four planets surrounding HR 8799. "It's fantastic to nab the spectra of four planets in a single observation," said co-author Gautam Vasisht, an astronomer at the Jet Propulsion Laboratory. The results are "quite strange," Oppenheimer said. "These warm, red planets are unlike any other known object in our universe. All four planets have different spectra, and all four are peculiar. The theorists have a lot of work to do now."

 

One of the most striking abnormalities is an apparent chemical imbalance. Basic chemistry predicts that ammonia and methane should naturally coexist in varying quantities unless they are in extremely cold or hot environments. Yet the spectra of the HR 8799 planets, all of which have "lukewarm" temperatures of about 1000 Kelvin (1340 degrees Fahrenheit), either have methane or ammonia, with little or no signs of their chemical partners. Other chemicals such as acetylene, previously undiscovered on any exoplanet, and carbon dioxide may be present as well.

 

"The spectra of these four worlds clearly show that they are far too toxic and hot to sustain life as we know it," said co-author Ian Parry, a senior lecturer at the Institute of Astronomy, Cambridge University. "But the really exciting thing is that one day, the techniques we've developed will give us our first secure evidence of the existence of life on a planet outside our solar system."

 

In addition to revealing unique planets, the research debuts a new capability to observe and rapidly characterize exosolar systems in a routine manner, something that has eluded astronomers until now because the light that stars emit is tens of millions to billions of times brighter than the light given off by planets. This makes directly imaging and analyzing exoplanets extremely difficult: as Oppenheimer says, "It's like taking a single picture of the Empire State Building from an airplane that reveals the height of the building as well as taking a picture of a bump on the sidewalk next to it that is as high as a couple of bacteria."

 

Altogether, the project has produced images of celestial objects 1 million to 10 million times fainter than the star at the center of the image, with only an hour of observations. It is also capable of measuring orbital motion of objects.

"Astronomers are now able to monitor cloudy skies on extrasolar planets, and for the first time, they have made such observations for four planets at once," said Maria Womack, program director for the Division of Astronomical Sciences at the National Science Foundation. "This new ability enables astronomers to now make comparisons as they track the atmospheres, and maybe even weather patterns, on the planets."

 

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The Solar Roadway - A Series of Structurally-Engineered Solar Panels that are Driven Upon

The Solar Roadway - A Series of Structurally-Engineered Solar Panels that are Driven Upon | Amazing Science | Scoop.it

Years ago, when the phrase "Global Warming" began gaining popularity, we started batting around the idea of replacing asphalt and concrete surfaces with solar panels that could be driven upon. We thought of the "black box" on airplanes: We didn't know what material that black box was made of, but it seemed to be able to protect sensitive electronics from the worst of airline crashes.

 

Suppose we made a section of road out of this material and housed solar cells to collect energy, which could pay for the cost of the panel, thereby creating a road that would pay for itself over time. What if we added LEDs to "paint" the road lines from beneath, lighting up the road for safer night time driving? What if we added a heating element in the surface (like the defrosting wire in the rear window of our cars) to prevent snow/ice accumulation in northern climates? The ideas and possibilities just continued to roll in and the Solar Roadway project was born.

 

Road Surface Layer - translucent and high-strength, it is rough enough to provide great traction, yet still passes sunlight through to the solar collector cells embedded within, along with LEDs and a heating element. It is capable of handling today's heaviest loads under the worst of conditions. Weatherproof, it protects the electronics layer beneath it.

 

Electronics Layer Contains a microprocessor board with support circuitry for sensing loads on the surface and controlling a heating element. No more snow/ice removal and no more school/business closings due to inclement weather. The on-board microprocessor controls lighting, communications, monitoring, etc. With a communications device every 12 feet, the Solar Roadway is an intelligent highway system.

 

Base Plate LayerLayer - While the electronics layer collects energy from the sun, it is the base plate layer that distributes power (collected from the electronics layer) and data signals (phone, TV, internet, etc.) "downline" to all homes and businesses connected to the Solar Roadway. Weatherproof, it protects the electronics layer above it.

 

Imagine a world-wide system where the "lit" half of the world is always powering the "dark" half of the world! Everyone has power. No more power shortages, no more roaming power outages, no more need to burn coal (50% of greenhouse gases). Less need for fossil fuels and less dependency upon foreign oil. Much less pollution. How about this for a long term advantage: an electric road allows all-electric vehicles to recharge anywhere: rest stops, parking lots, etc. They would then have the same range as a gasoline-powered vehicle. Internal combustion engines would become obsolete. Our dependency on oil would come to an abrupt end. 


It's time to upgrade our infrastructure - roads and power grid - to the 21st century.

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Mummies reveal that clogged arteries plagued the ancient world, even hunter gatherers with no food supply

Mummies reveal that clogged arteries plagued the ancient world, even hunter gatherers with no food supply | Amazing Science | Scoop.it

Clogged arteries are seen as the quintessential symptom of an unhealthy modern lifestyle. But the condition was common across the ancient world, even among active hunter–gatherers with no access to junk food, a study of mummies has found.

 

“There’s a belief that if we go back in time, everything’s going to be OK,” says cardiologist Greg Thomas of the University of California, Irvine, a senior member of the study team. “But these mummies still have coronary artery disease.”

 

In atherosclerosis, arteries become narrowed and hardened by plaques — made up of cholesterol and immune cells called macrophages — that build up in their walls. The condition can lead to heart attacks, stroke and other cardiovascular diseases and is the leading cause of death in the developed world.

 

A lack of exercise and a diet high in saturated fat — both of which increase levels of 'bad' cholesterol in the blood — are thought to increase the risk of plaques building up. This has led to the suggestion that to avoid heart disease we should try to live more like our hunter–gatherer ancestors, on a diet of unprocessed foods high in protein and unsaturated fats.

 

To find out if that’s really true, Thomas and his colleagues performed CT scans on 137 mummies from four very different ancient populations: Egyptian, Peruvian, the Ancestral Puebloans of southwest America and the Unangans of the Aleutian Islands in Alaska. The Egyptians were artificially embalmed, whereas the other bodies were  preserved naturally by very dry or very cold conditions. The four groups had different lifestyles — the Ancestral Puebloans were forager–farmers, for example, whereas the Unangan were hunter–gatherers with an exclusively marine diet.

 

The researchers checked the mummies’ scans for calcified plaques in the wall of an artery or along the expected course of an artery. They diagnosed probable or definite atherosclerosis in 47 (34%) of the 137 mummies, and in all four populations, ranging from 25% of the 51 ancient Peruvians to 60% of the five Unangans.

 

The researchers say that they found a level of disease equivalent to that in modern populations — a result Thomas describes as “a shock”. “Now we’ve scanned the common man and woman and they’ve got the same disease,” says Thomas. Rather than excess cholesterol, he suggests that high levels of inflammation — caused by smoke inhalation or chronic infection, for instance — may have triggered the disease in these individuals. But Thomas says that cardiovascular disease should not now be seen as simply a consequence of an unhealthy lifestyle. “We’ve oversold the ability to stop heart disease,” he says. “We can slow it down, but to think we can prevent it is unrealistic.”

 

 

 

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Cassandra Folkerth's curator insight, September 28, 2013 5:16 PM

This is crazy! I guess I shouldnt be too suprised. But the fact that people back in the ancient world had clogged arteries is amazing to me. For some reason  thought since they didnt have processed foods and were most likely eating healthier than we do that they'd have better health. Especially people who were mummified. They were the people with money and still were killed due to poor health. Were not as different as I thought. 

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Mice Learn Faster with Human Glia

Mice Learn Faster with Human Glia | Amazing Science | Scoop.it

Mice that received transplants of human glial progenitor cells learned much more quickly than normal mice, according to a study published today (March 7) in Cell Stem Cell. The findings support the theory that glial cells made a significant contribution to the evolution of our own enhanced cognitive abilities.

 

“This work is very exciting and surprising because it demonstrates that there may be something special about human glial progenitor cells that contribute to the amazing complexity and computational abilities of the human brain,” said Robert Malenka, a neuroscientist at Stanford University who was not involved in the study, in an email to The Scientist.

 

For many years, glia cells, non-neuronal cells present in the same numbers as neurons in the brain, were thought to play only a supporting role, providing structure, insulation, and nutrients for neurons. But in the past 20 years it has become clear that glia also participate in the transmission of electrical signals. Specifically, astrocytes—a type of glial cell with thousands of tendrils that reach and encase synapses—can modulate signals passing between neurons and affect the strength of those connections over time.

Recent studies have also demonstrated that human astrocytes are very different from those found in mouse and rat brains, on which most previous studies of astrocyte physiology were based. Human astrocytes are more numerous, larger, and more complex, and they are capable of far more rapid signaling responses than rodent astrocytes.

 

Together, these results suggest that astrocytes may have been critical to the evolution of enhanced neural processing in humans. Having already transplanted human glial progenitor cells (GPCs) to restore myelination in myelin-deficient mice, Steven Goldman of University of Rochester Medical Center in New York and colleagues realized that they could repeat the trick in normal mice to assess the contribution of human-specific astrocytes to synaptic plasticity and learning.

 

Goldman’s team grafted human GPCs into the brain of baby mice and waited until they became adults, by which time a large proportion of their forebrain glia were replaced by human cells differentiated from the GPCs, including astrocytes with the same structure and functional capabilities as in humans. The researchers then looked at long-term potentiation (LTP)—the strengthening of synaptic connections and a key mechanism underlying learning—in the hippocampus, and found that it was significantly enhanced in mice with human GPCs compared with normal mice and mice engrafted with mouse GPCs. Goldman and colleagues also assessed the performance of the mice on several behavioral tasks that measure leaning and memory—including auditory fear conditioning, a maze test, and object-location memory—and found across the board that mice with human GPCs learned significantly more quickly than normal mice.


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Spymaster Orcasub: The $2 million made-to-order private submarine shown at Harrods

Spymaster Orcasub: The $2 million made-to-order private submarine shown at Harrods | Amazing Science | Scoop.it

It wasn't just £20k bling headphones to be found at the Harrods Technology 2.0 showcase, as Spymaster - best known for its security devices - had something far cooler and far pricier on show: a mock-up of a $2-million private submarine. Yes, you read that right.

 

While many might describe this mini marvel as an overpriced toy, who wouldn't want to go exploring the underwater depths by themselves? It's all very James Bond... or is that more James Cameron?

 

The 22ft-long, 4-tonne Orcasub is built to Lloyd's Register standards and the base model can descend to 1,000ft without a hitch. It's designed to be controlled by joystick and pedals and based on the principles of flight: by using thrust, lift and drag the made-to-order sub can bank, curve and turn much like a private plane.

 

The battery-powered Orcasub comes with 80 hours of life support in each of its two 360-degree open-view pods, has multi-beam collision-avoidance sonar so you know what's going on around you, a digital long-range underwater communication system to keep in contact with the world above and a 60,000 lumen Nuytco NewtSun ultra-LED lighting system to light up the surrounding water.

 

Although we doubt that the muddied waters of Margate will be all too appealing to prospective buyers, the Orcasub sure does sound like the ultimate gadget - if it can even be called that - for those beautiful, clear waters of the world. You know, the kind of places where the rich own their own private islands and, in the not too distant future, their own private submarines too.

 

If 2,000ft isn't deep enough for your likes then prepare to delve deeper into the abyss of those apparently bottomless pockets: varying depth-capable productions are available to order, maxing out at the $9.32-million version that can descend to 6,000ft.

 

Spymaster will throw in five day's training into the price which, given the multimillion-dollar cost price, seems, we suppose, fairly reasonable.

Now all we just need is for Spymaster to team up with Lotus to make that ultimate fantasy car-meets-sub a reality so the mega rich can play out theirJames Bond dreams like never before.

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Bees on caffeine remember better and coffee and citrus plants exploit this effect for pollination

Bees on caffeine remember better and coffee and citrus plants exploit this effect for pollination | Amazing Science | Scoop.it
Coffee and citrus plants use caffeine to manipulate the memory of honeybees, a new study says.

 

A cup of coffee doesn't just provide a jolt for people in the morning. Bees may crave a buzz too. Scientists have found that some plants, like the coffee plant (Coffea), use caffeine to manipulate the memory of bees. The nectar in their flowers holds low levels of caffeine that pollinators find highly rewarding.


Bitter-tasting caffeine primarily arose in plants as a toxic defense against herbivores like garden slugs. At high doses, caffeine can be toxic and repellent to pollinators.

 

However, at low concentrations, caffeine appears to have a secondary advantage, attracting honeybees and enhancing their long-term memory, said lead author Geraldine Wright, a neuroscientist at Newcastle University in England, whose study was published online March 7 in the journal Science.


"We show that caffeine—a compound whose ecological role is mainly to deter and poison herbivores—actually acts like a drug in an ecologically relevant context," Wright said. "The plant is secretly drugging the pollinator. It may help the bee, but the plant cares more about having a pollinator with high fidelity!"


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Human Peptide Hormone Hypocretin-1 (Orexin) Linked to Happiness and Anti-Depression

Human Peptide Hormone Hypocretin-1 (Orexin) Linked to Happiness and Anti-Depression | Amazing Science | Scoop.it
An international team of scientists has found that levels of a peptide called hypocretin increase when humans are happy but decrease when they are sad.

 

The neurochemical changes underlying human emotions and social behaviour are largely unknown. A team of scientists now reports on the changes in the levels of two hypothalamic neuropeptides,hypocretin-1 and melanin-concentrating hormone (MCH), measured in the human amygdala. The team shows that hypocretin-1 levels are maximal during positive emotion, social interaction and anger, behaviors that induce cataplexy in human narcoleptics.


In contrast, MCH levels are minimal during social interaction, but are increased after eating. Both peptides are at minimal levels during periods of postoperative pain despite high levels of arousal. Melanin-concentrating hormone levels increase at sleep onset, consistent with a role in sleep induction, whereas hypocretin-1 levels increase at wake onset, consistent with a role in wake induction. Levels of these two peptides in humans are not simply linked to arousal, but rather to specific emotions and state transitions. Other arousal systems may be similarly emotionally specialized.


“The current findings explain the sleepiness of narcolepsy, as well as the depression that frequently accompanies this disorder,” said senior author Prof Jerome Siegel of the University of California Los Angeles’ Semel Institute for Neuroscience and Human Behavior. “The findings also suggest that hypocretin deficiency may underlie depression from other causes.”

 

“Depression is the leading cause of psychiatric disability in the U.S,” Prof Siegel said. “More than 6 percent of the population is affected each year, with lifetime prevalence exceeding 15 percent. Yet the use of antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), has not been based on evidence of a deficiency, or excess, of any neurotransmitter. Several recent studies have questioned whether SSRIs, as well as other depression-fighting drugs, are any more effective than placebos.”


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Out Of Nothing: Dynamical Casimir effect in metamaterial converts vacuum fluctuations into real photons

Out Of Nothing: Dynamical Casimir effect in metamaterial converts vacuum fluctuations into real photons | Amazing Science | Scoop.it

In the strange world of quantum mechanics, the vacuum state (sometimes referred to as the quantum vacuum, simply as the vacuum) is a quantum system's lowest possible energy state. While not containing physical particles, neither is it an empty void: Rather, the quantum vacuum contains fluctuating electromagnetic waves and so-called virtual particles, the latter being known to transition into and out of existence. In addition, the vacuum state has zero-point energy – the lowest quantized energy level of a quantum mechanical system – that manifests itself as the static Casimir effect, an attractive interaction between the opposite walls of an electromagnetic cavity. Recently, scientists at Aalto University in Finland and VTT Technical Research Centre of Finland demonstrated the dynamical Casimir effect using a Josephson metamaterial embedded in a microwave cavity. They showed that under certain conditions, real photons are generated in pairs, and concluded that their creation was consistent with quantum field theory predictions.


Researcher Pasi Lähteenmäki discussed the challenges he and his colleagues – G. S. Paraoanu, Juha Hassel and Pertti J. Hakonen – encountered in their study. Regarding their demonstration of the dynamical Casimir effect using a Josephson metamaterial embedded in a microwave cavity at 5.4 GHz, Lähteenmäki tells Phys.org that the main challenge in general is to get high-quality samples. In addition, Lähteenmäki adds, they had to ensure that the origin of the noise is quantum and not some unaccounted source of excess noise, such as thermal imbalance between the environment and the sample, or possibly leakage of external noise.

 

Modulating the effective length of the cavity by flux-biasing the SQUID (superconducting quantum interference device) metamaterial had its challenges as well. "The pump signal needs to be rather strong, yet at the same time one wants to be sure that no excess noise enters the system through the pump line, Lähteenmäki notes, "and good filtering means high attenuation, which is a requirement contradictory to a strong signal. Also," Lähteenmäki continues, "at 10.8 GHz the pump frequency is rather high – and at that frequency range both the sample and the setup is rather prone to electrical resonances which can limit the usable frequencies." In short, the flux profile needs to be such that the pumping doesn't counteract itself. In addition, trapping flux in SQUID loops can also become a problem, limiting the range of optimal operating points and causing excess loss.

 

The researchers also showed that photons at frequencies symmetric with respect to half the modulation frequency of the cavity are generated in pairs. "In general, with frequency locked signal analyzers today the extraction of this correlation is not particularly problematic – especially since the low noise amplifier noise is not correlated at different frequencies," Lähteenmäki explains. That said, issues related to data collection and averaging include amplifier gain drift and phase randomization of the pump signal (relative to the detection phase) if the state of the generator is changed. "The noise temperature of the low noise amplifier sets some limits to the amount of data that needs to be collected, especially in the case where one is operating in the regime of low parametric gain."

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New evidence that red wine component resveratrol activates SIRT1 pathway and prolongs life

New evidence that red wine component resveratrol activates SIRT1 pathway and prolongs life | Amazing Science | Scoop.it

A new study demonstrates what researchers consider conclusive evidence that the red wine compound resveratrol directly activates a protein that promotes health and longevity in animal models. What’s more, the researchers have uncovered the molecular mechanism for this interaction, and show that a class of more potent drugs currently in clinical trials act in a similar fashion. Pharmaceutical compounds similar to resveratrol may potentially treat and prevent diseases related to aging in people, the authors contend.

 

For the last decade, the science of aging has increasingly focused onsirtuins, a group of genes that are believed to protect many organisms, including mammals, against diseases of aging. Mounting evidence has demonstrated that resveratrol, a compound found in the skin of grapes as well as in peanuts and berries, increases the activity of a specific sirtuin, SIRT1, that protects the body from diseases by revving up the mitochondria, a kind of cellular battery that slowly runs down as we age. By recharging the batteries, SIRT1 can have profound effects on health.

 

Mice on resveratrol have twice the endurance and are relatively immune from effects of obesity and aging. In experiments with yeast, nematodes, bees, flies and mice, lifespan has been extended.

 

“In the history of pharmaceuticals, there has never been a drug that binds to a protein to make it run faster in the way that resveratrol activates SIRT1,” said David Sinclair, Harvard Medical School professor of genetics. “Almost all drugs either slow or block them.”

 

In 2006, Sinclair’s group published a study showing that resveratrol could extend the lifespan of mice, and the company Sirtris Pharmaceuticals, which was started by HMS researchers, was founded to make drugs more potent than resveratrol. Sinclair is a co-founder of Sirtris, a GlaxoSmithKline company, and remains a scientific advisor. Sirtris currently has a number of sirtuin-activating compounds in clinical trials.

 

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Tony Barnes's curator insight, March 9, 2013 12:00 PM

I remember  in the 1970s there was talk of tocopherols having something this kind of health effect.  My chemistry's now rusty. Maybe resveratrol is a tocoperol. Anyway, it's very interesting.

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Nanoscale Device Makes Light Travel Infinitely Fast

Nanoscale Device Makes Light Travel Infinitely Fast | Amazing Science | Scoop.it

Within a nanometer-scale device, visible light travels infinitely fast—by one measure—a team of physicists and engineers reports. The gizmo won't lead to instantaneous communication—the famous speed limit of Albert Einstein's theory of relativity remains in force—but it could have a variety of uses, including serving as an element in a type of optical circuitry.

 

"The demonstration of such a thing is definitely very interesting and possibly useful," says Wenshan Cai, an electrical engineer at the Georgia Institute of Technology in Atlanta, who was not involved in the work.

 

In empty space, light always travels at 300,000,000 meters per second. In a material such as glass, it travels slower. The ratio of light's speed in the vacuum to its speed in a material defines the material's "index of refraction," which is typically greater than one. However, scientists have begun to manipulate the interactions of light and matter to tune the index of refraction in weird ways, such as making it negative, which leads to an unusual bending of light.

 

Now, Albert Polman, a physicist at the FOM Institute for Atomic and Molecular Physics in Amsterdam; Nader Engheta, an electrical engineer at the University of Pennsylvania; and colleagues have pulled off a particularly odd feat. They've developed a tiny device in which the index of refraction for visible light is zero—so that light waves of a particular wavelength move infinitely fast.

 

The device consists of a rectangular bar of insulating silicon dioxide 85 nanometers thick and 2000 nanometers long surrounded by conducing silver, which light generally doesn't penetrate. The result is a light-conveying chamber called a waveguide. Researchers fashioned different devices in which the width of the silicon dioxide ranged from 120 to 400 nanometers.

 

Light behaves differently in such a waveguide, because the electromagnetic fields must obey certain "boundary conditions" on the sides of the device. Short-wavelength light bounces back and forth between the ends of the guide, and the peaks and troughs of the counter-propagating light waves overlap to create a pattern of bright and dark bands much like the pressure patterns with a ringing organ pipe. Above a "cutoff" wavelength, light doesn't flow at all.

 

Right at the cutoff wavelength, things get interesting. Instead of producing a banded pattern, the whole waveguide lights up. That means that instead of acting as waves with equally spaced peaks, or "phase fronts," the wave behaves as if its peaks are moving infinitely fast and are everywhere at once. So the light oscillates in synchrony along the length of the waveguide.

Engheta and company had previously created an index of refraction of zero for longer-wavelength radiation called microwaves. Repeating the feat for visible light was harder, as the new widget is too small to contain a light source. Instead, the researchers shot in a beam of electrons to generate light of all wavelengths within the waveguide and measured the light leaking out of it. The amount of light shining out at a particular wavelength depends on whether the electron beam enters at a point where there should be a dark or a bright spot for that wavelength. So by scanning the beam along the waveguide and monitoring the output, researchers traced the light pattern at each wavelength. "It is nanofabrication and characterization at its best," says Che Ting Chan, a physicist at the Hong Kong University of Science and Technology.

 

So how does an everywhere-at-once light wave not violate relativity? Light has two speeds, Engheta explains. The "phase velocity" describes how fast waves of a given wavelength move, and the "group velocity" describes how fast the light conveys energy or information. Only the group velocity must stay below the speed of light in a vacuum, Engheta says, and inside the waveguide, it does.

The device could hav

e various uses, Engheta says. Because the light leaking out of the waveguide is all in synch, the waveguide might be bent to form an antenna that emits light wave with sculpted phase fronts, he says. It might also make a conduit for a hoped-for type of nanoscale optical circuitry, he says.

 

An array of such waveguides might even make a bulk material with zero index of refraction. But fabricating that array would be very challenging, Cai says: "In theory it's easy; experimentally it's very hard."

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Josh C.'s curator insight, March 13, 2013 9:33 AM

I keep myslef hopeful of the future of this world. This is one of the ways that I can keep track of that. The new things we can do are amazing compared to just one decade ago!

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Mouse cloning record broken – generation 25 from a single mouse!

Mouse cloning record broken – generation 25 from a single mouse! | Amazing Science | Scoop.it

After cloning 25 generations from a single mouse, the next step for a Japanese lab is to attempt to make clones from mouse fur, stuffed bodies and mouse cells in excrement.

 

Teruhiko Wakayama at the RIKEN Center for Developmental Biology in Kobe, Japan, who carried out the work, says the technique could help in producing high-quality animals for farms and conservation purposes. "If a 'super cow' that could produce a lot of milk or Kobe beef could be cloned at low cost, then not only consumers but also farmers would be happy," he says.

 

Twenty-five generations of clones have come from the mouse, and all 580 of them were healthy, lived normal lifespans and could have healthy pups through normal mating.

 

In 2008, Wakayama's team produced clones from dead mice that had been frozen for 16 years. "My lab is now trying to make cloned mice from fur, stuffed bodies, and excrement," says Wakayama. 

 

Enthusiasm for therapeutic cloning, as the technique that led to Dolly the sheep is known, waned in the mid-2000s following scientific fraud scandals in South Korea and the difficulty of producing animals without abnormalities. Researchers struggled to produce cloned cattle, pigs, cats and dogs beyond two or three generations.

 

Now Wakayama's team has emphatically broken through this barrier thanks to a chemical which more faithfully resets the cell nucleus to be cloned back to an embryonic state.

 

First, the team emptied a mouse egg cell of its nucleus. Then they inserted a nucleus from the adult mouse to be cloned before putting this cell into a bath of an enzyme blocker called trichostatin. The resulting embryos – all females – had fewer abnormalities in their histones, the packing materials for chromosomes.

 

Previous studies had identified faulty histones in cloned embryos as a possible reason for the poor success rate of cloning, as well as clone abnormalities. A possible explanation for the previous limit on the number of "reclones" is a build up of such abnormalities over successive generations.

 

"So far, nobody has been able to explain the reason for this," says Wakayama. "We thought that this limitation was caused by the accumulation of genetic or epigenetic abnormalities."

 

"This is very impressive work. If this translates to other mammalian species – including humans – it could be a major game changer," says Robert Lanza, chief medical officer at Advanced Cell Technology, a company based in Marlborough, Massachusetts, that is developing treatments based on stem cells.

 

Wakayama says he doesn't know if his technique will make it easier to clone primates, let alone humans, and has no plans to try. "I am a mouse researcher and have no experience with other species. I will not even attempt to use rats, because male rats are extremely difficult to clone." One application of cloning is to preserve endangered species, as advocated late last year by Brazil. The ability to make clones from fur, specimens preserved in museums and excrement would potentially allow the "resurrection" of extinct animals.

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Aidan Skelley's curator insight, March 14, 2013 6:23 AM

Slightly Creepy but could get us ahead in life

 

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NASA Rover Finds Conditions Once Suited for Ancient Life on Mars

NASA Rover Finds Conditions Once Suited for Ancient Life on Mars | Amazing Science | Scoop.it
An analysis of a rock sample collected by NASA's Curiosity rover shows ancient Mars could have supported living microbes.

 

Scientists identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon -- some of the key chemical ingredients for life -- in the powder Curiosity drilled out of a sedimentary rock near an ancient stream bed in Gale Crater on the Red Planet last month. 

"A fundamental question for this mission is whether Mars could have supported a habitable environment," said Michael Meyer, lead scientist for NASA's Mars Exploration Program at the agency's headquarters in Washington. "From what we know now, the answer is yes." 

Clues to this habitable environment come from data returned by the rover's Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments. The data indicate the Yellowknife Bay area the rover is exploring was the end of an ancient river system or an intermittently wet lake bed that could have provided chemical energy and other favorable conditions for microbes. The rock is made up of a fine-grained mudstone containing clay minerals, sulfate minerals and other chemicals. This ancient wet environment, unlike some others on Mars, was not harshly oxidizing, acidic or extremely salty. 

The patch of bedrock where Curiosity drilled for its first sample lies in an ancient network of stream channels descending from the rim of Gale Crater. The bedrock also is fine-grained mudstone and shows evidence of multiple periods of wet conditions, including nodules and veins. 

Curiosity's drill collected the sample at a site just a few hundred yards away from where the rover earlier found an ancient streambed in September 2012. 

"Clay minerals make up at least 20 percent of the composition of this sample," said David Blake, principal investigator for the CheMin instrument at NASA's Ames Research Center in Moffett Field, Calif. 

These clay minerals are a product of the reaction of relatively fresh water with igneous minerals, such as olivine, also present in the sediment. The reaction could have taken place within the sedimentary deposit, during transport of the sediment, or in the source region of the sediment. The presence of calcium sulfate along with the clay suggests the soil is neutral or mildly alkaline. 

Scientists were surprised to find a mixture of oxidized, less-oxidized, and even non-oxidized chemicals, providing an energy gradient of the sort many microbes on Earth exploit to live. This partial oxidation was first hinted at when the drill cuttings were revealed to be gray rather than red. 

"The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms," said Paul Mahaffy, principal investigator of the SAM suite of instruments at NASA's Goddard Space Flight Center in Greenbelt, Md.

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Designing interlocking building blocks to create complex biological tissues

Designing interlocking building blocks to create complex biological tissues | Amazing Science | Scoop.it

Researchers at Columbia Engineering have developed a new "plug-and-play" method to assemble complex cell microenvironments that is a scalable, highly precise way to fabricate tissues with any spatial organization or interest -- such as those found in the heart or skeleton or vasculature. The study reveals new ways to better mimic the enormous complexity of tissue development, regeneration, and disease.


"George Eng, an MD/PhD student in my lab who just received his doctoral degree, designed a lock-and-key technique to build cellular assemblies using a variety of shapes that lock into templates much the way you would use LEGO building blocks," says Gordana Vunjak-Novakovic, who led the study and is the Mikati Foundation Professor of Biomedical Engineering at Columbia Engineering and professor of medical sciences. "What is really important about this technique is that these shapes are tiny -- just a fraction of millimeter, the thickness of a human hair -- and that their precise arrangements are made using cell-friendly hydrogels."


Tissue cells in the human body form specific architectures that are critical for the function of each tissue. Cardiac cells, for example, are aligned to create maximum force acting in one direction. Cells without specific spatial organization may never become fully functional if they do not recapitulate their intrinsic organization found in the body. The Columbia Engineering technique enables researchers to construct unique and controlled cell patterns that allow precise studies of cell function, so that, Vunjak-Novakovic adds, "we can now ask some of the more complex questions about how the cells respond to the entire context of their environment. This will help us explore cellular behavior during the progression of disease and test the effects of drugs, stem cells, and various other therapeutic measures."


"We used a LEGO-like lock-and-key docking system to spatially localize different cell populations with high specificity and precision," Eng explains. "And, since each shape is docking independent of each other, large tissues can be organized simultaneously, instead of having to create a sequential, brick-by-brick type of organization. With this method, we can design and create better tissues for potential organ replacement."

 

"The beauty of this method is that complex configurations of living cellular material -- many different types of cells, molecules, and extracellular materials -- emerge in the lab in precise three-dimensional geometries in a way that can be used by anyone, as no special equipment is involved," Vunjak-Novakovic adds.

 

Eng is excited about leveraging the microtechnologies used to make computer chips with biomedical engineering techniques to make cells to fabricate new organs. "We develop new ideas and methods to try and alleviate disease by assembling tiny subunits of cells into larger, more functional organs," he says. "It's really like a scene from science fiction! To be on the frontier of scientific discovery, developing new methods and products that we hope will have therapeutic benefit for people is quite fulfilling and motivating. And there's such an exciting element of discovery in designing new cellular microenvironments, studying the rules that define cell communication and organization."

 

Next steps in the application of this new technique include fabrication of different types of functional tissues, such as well-organized cardiac muscle, a tissue whose function critically depends on its architecture and cell alignment, incorporating blood vessel networks along with organized cardiac cells. The method will also be extended to the design of pathological microenvironments of interest, such as tumor models.

 

"Our lab has worked for many years in building 'human-on-a-chip' systems that will allow us to see cellular responses representative of those of whole body physiology," says Vunjak-Novakovic. "We're also very interested in developing technologies that can advance biological experimentation and allow us to ask more complex questions. This study, which was conducted over the last four years, is contributing to both of these areas and helping us advance our methods for screening of therapeutic cells and factors."


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Lake Hillier: The Pink lake in Australia

Lake Hillier: The Pink lake in Australia | Amazing Science | Scoop.it

There are many bizarre things in Australia, but few go even close to the pink lake Hillier.


Lake Hillier is a pink-coloured lake on Middle Island in Western Australia – the largest island from the Recherche Archipelago, a group of about 105 islands. A narrow strip of land composed of sand dunes covered by vegetation separates it from the ocean. The tiny lake only spans 600 meters wide, but the pink color is just unmistakable – and downright weird. What you’re seeing around it is a ime of white salt and a dense woodland of Paperbark and Eucalypt trees. The first reported sighting dates back to the journals of Matthew Flinders, a British navigator and hydrographer in 1802. Nobody knows exactly why it’s pink! The flamboyant rose pink color does not alter when you take the water and put it into a container, and many biologists believe this is all caused by a combination of low nutrient concentrations and bacteria (Dunaliella salina & Halobacterium, to be more precise).

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Vaccine hope for Tasmanian devil tumor disease

Vaccine hope for Tasmanian devil tumor disease | Amazing Science | Scoop.it
Researchers discover how transmissible facial cancer hides from the immune system.

 

Tasmanian devils are dying of a contagious cancer called devil facial tumor disease, which spreads between animals when they tussle over food. Now, a team of scientists has discovered how the disease infects new hosts by sneaking past the devil's immune system. The work could help in developing a vaccine that might prevent healthy devils from catching the cancer.

 

“It’s probably the most promising lead we’ve had for a vaccine since the initial characterization of the disease,” says immunogeneticist Hannah Siddle of the University of Cambridge, UK. Devil facial tumor disease emerged in 1996 and has slashed the Tasmanian devil population by 60%. If left unchecked, it could drive the species to extinction in 20–30 years.


Researchers had assumed that the disease spread easily between animals because of the devil's low genetic diversity, particularly in the genes of the major histocompatibility complex (MHC), which produce proteins that sit on the surface of cells and help the immune system to detect threats such as viruses or tumors. Once the disease emerged in one devil, presumably dodging its immune system by producing these proteins, it was thought that it would be able to fool the immune defences of the whole population.


But rather than producing the same MHC molecules found across all devils, Siddle and her colleagues found that the cancerous cells do not produce MHC molecules at all. “That was a big surprise,” she says. More surprising still was that the MHC genes in tumor cells had not been disabled by mutations. Instead, the genes responsible for the production of three proteins — β2-microglobulin, TAP1 and TAP2 — had been largely switched off. These proteins are necessary for transporting MHC to a cell’s membrane. Siddle even managed to reverse this problem using interferon-γ — a molecule that is known to encourage the production of MHC proteins. “The fact that it worked was wonderful and made perfect sense,” says Jim Kaufman, who was lead investigator on the study.


It is unclear if devil facial tumor disease will also evolve to be less aggressive with time, but with the Tasmanian devil facing extinction, Kaufman is not waiting to find out. He and his team are now working with Australian colleagues to develop a vaccine. Their plan is to prime healthy devils by giving them cancerous cells that already bear MHC proteins. Their immune systems should then recognize either tiny amounts of MHC on the surface of a cancer cell, or other proteins released as the tumors grow. “We’d start enough of an immune response to tip the balance in favour of the devil,” says Kaufman. “We’ve got some way to go, but we feel quite hopeful that we’ll come up with something.”


Although the priority is to save the Tasmanian devil from extinction, Kaufman also thinks that such research is important should a contagious cancer ever evolve to spread between humans. “Every once in a while, a new disease comes out of nowhere,” he says. “It’s useful to know what might hit people or other animals in the future.”


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NASA: Amplified Greenhouse Effect Shifts North's Growing Seasons

NASA: Amplified Greenhouse Effect Shifts North's Growing Seasons | Amazing Science | Scoop.it
Vegetation growth at Earth's northern latitudes increasingly resembles lusher latitudes to the south, according to a NASA-funded study.

 

Vegetation growth at Earth's northern latitudes increasingly resembles lusher latitudes to the south, according to a NASA-funded study based on a 30-year record of land surface and newly improved satellite data sets. Of the 10 million square miles (26 million square kilometers) of northern vegetated lands, 34 to 41 percent showed increases in plant growth (green and blue), 3 to 5 percent showed decreases in plant growth (orange and red), and 51 to 62 percent showed no changes (yellow) over the past 30 years. Satellite data in this visualization are from the AVHRR and MODIS instruments, which contribute to a vegetation index that allows researchers to track changes in plant growth over large areas.

An international team of university and NASA scientists examined the relationship between changes in surface temperature and vegetation growth from 45 degrees north latitude to the Arctic Ocean. Results show temperature and vegetation growth at northern latitudes now resemble those found 4 degrees to 6 degrees of latitude farther south as recently as 1982.

"Higher northern latitudes are getting warmer, Arctic sea ice and the duration of snow cover are diminishing, the growing season is getting longer and plants are growing more," said Ranga Myneni of Boston University's Department of Earth and Environment. "In the north's Arctic and boreal areas, the characteristics of the seasons are changing, leading to great disruptions for plants and related ecosystems."

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Sticky Feet: Ants have incredibly sticky feet, they can hang onto ceilings carrying 100 times their body weight

But if they are stuck down so successfully - how do they ever get them unstuck? Chris Clemente is studying the mechanisms that ants and other insects (especially cockroaches) use to stick and unstick, and also to walk down as well as up walls. He also considers the applications that this might one day help to develop a 'supersuper glue' and to improve the movement of robots.

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Sandy Honess's curator insight, March 14, 2013 9:24 AM

This is amazing.  Asian weaver ant.   Fluid filled ant feet makes them stick.  This guy would make a great speaker at pest management events. I wish he was here in the States.  

 

 

Sandy Honess's curator insight, March 14, 2013 9:40 AM

This is amazing.  I have never viewed a breakdown of how ants and roaches travel and can hold on to smooth surfaces, upside down, like this expert has demonstrated.    

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Irreversible Evolution? Dust Mites Show Parasites Can Violate Dollo’s Law

Irreversible Evolution? Dust Mites Show Parasites Can Violate Dollo’s Law | Amazing Science | Scoop.it

Our world is quite literally lousy with parasites. We are hosts to hundreds of them, and they are so common that in some ecosystems, the total mass of them can outweigh top predators by 20 fold. Even parasites have parasites. It’s such a good strategy that over 40% of all known species are parasitic. They steal genes from their hosts, take over other animals’ bodies, and generally screw with their hosts’ heads. But there’s one thing that we believed they couldn’t do: stop being parasites. Once the genetic machinery set the lifestyle choice in motion, there’s supposed to be no going back to living freely. Once a parasite, always a parasite - unless you’re a mite.

 

In evolutionary biology, the notion of irreversibility is known as Dollo’s Law after the Belgian paleontologist that first hypothesized it in 1893. He stated that once a lineage had lost or modified organs or structures, that they couldn’t turn back the clock and un-evolve those changes. Or, as he put it, “an organism is unable to return, even partially, to a previous stage already realized in the ranks of its ancestors.”

 

While some animals seem to challenge Dollo’s Law, it has long been a deeply held belief in the field of parasitology. Parasitism is, in general, a process of reduction. Adjusting to survival on or in another animal is a severe evolutionary undertaking, and many parasites lose entire organs or even body systems, becoming entirely dependent on their hosts to perform biological tasks like breaking down food or locomotion. Parasitology textbooks often talk about the irreversibility of becoming a parasite in very finite terms. “Parasites as a whole are worthy examples of the inexorable march of evolution into blind alleys” says Noble & Noble’s 1976 Parasitology: the Biology of Animal Parasites.

 

Robert Poulin is even more direct: “Once they are dependent on the host there is no going back. In other words, early specialisation for a parasitic life commits a lineage forever.” Now, parasites are proving that not only can they evade immune systems, trick other animals, and use their hosts’ bodies in hundreds of nefarious ways, some can go back to living on their own. This is exactly what scientists now believed happened in the Pyroglyphidae — the dust mites.

 

Mites, as a whole, are a frighteningly successful but often overlooked group of organisms. More than 48,000 species have been described. These minuscule relatives of spiders can be found worldwide in just about every habitat you can imagine. Many are free-living, but there are also a number of parasitic species, including all-too-familiar pests like Sarcoptes scabiei, the mite which causes scabies. Exactly how the different groups of mites are related to each other, however, has been a hot topic of debate amongst mite biologists. Though the closest relatives of dust mites are the Psoroptidia, a large and diverse parasitic group of mites, many have argued that dust mites came from free-living ancestors — ‘living fossils’ of a sort, the only surviving line of ancestral free-living mites that later gave rise to parasites. In fact, Pavel Klimov and Barry O’Connor from the University of Michigan were able to find 62 different hypothesis as to how the free-living the dust mites fit into the mite family tree. Sixty-two, the team decided, was simply too many. So, they turned to the mites’ genes.

 

To test which of the hypotheses had the most merit, Klimov and O’Conner conscripted a team of 64 biologists in 19 countries to obtain over 700 mite specimens, which they then used to construct a mite family tree. They sequenced five nuclear genes from each species, then applied statistical analyses to construct a tree of relationships called a phylogeny. And that’s when they saw it: deeply nested inside a large group of parasites were our everyday, non-parasitic, allergy-causing dust mites.

 

“This result was so surprising that we decided to contact our colleagues to obtain their feedback prior to sending these data for publication,” said lead author Pavel Klimov. “Parasites can quickly evolve highly sophisticated mechanisms for host exploitation and can lose their ability to function away from the host body,” he explained. “Many researchers in the field perceive such specialization as evolutionarily irreversible.” But, their data were clear. “All our analyses conclusively demonstrated that house dust mites have abandoned a parasitic lifestyle, secondarily becoming free-living.”

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Red alga borrows genes from bacteria to enable it to thrive in toxic environment containing high acidity and toxic metals

Red alga borrows genes from bacteria to enable it to thrive in toxic environment containing high acidity and toxic metals | Amazing Science | Scoop.it

In hot springs of Yellowstone National Park, lives an "extremophile" red alga, Galdieria sulphuraria. Galdieria uses energy from the sun to produce sugars through photosynthesis. In the darkness of old mineshafts in drainage as caustic as battery acid, it feeds on bacteria and survives high concentrations of arsenic and heavy metals.

 

How has a one-celled alga acquired such flexibility and resilience? To answer this question, an international research team led by Gerald Schoenknecht of Oklahoma State University and Andreas Weber and Martin Lercher of Heinrich-Heine-Universitat (Heinrich-Heine University) in Dusseldorf, Germany, decoded genetic information in Galdieria. The scientists made an unexpected discovery: Galdieria's genome shows clear signs of borrowing genes from its neighbors. Many genes that contribute to Galdieria's adaptations were not inherited from its ancestor red algae, but were acquired from bacteria or archaebacteria.

 

This "horizontal gene transfer" is typical for the evolution of bacteria, researchers say. However, Galdieria is the first known organism with a nucleus (called a eukaryote) that has adapted to extreme environments based on horizontal gene transfer.

 

"The age of comparative genome sequencing began only slightly more than a decade ago, and revealed a new mechanism of evolution--horizontal gene transfer--that would not have been discovered any other way," says Matt Kane, program director in the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research.

"This finding extends our understanding of the role that this mechanism plays in evolution to eukaryotic microorganisms." The alga owes its ability to survive the toxic effects of such elements as mercury and arsenic to transport proteins and enzymes that originated in genes it swiped from bacteria.

 

It also copied genes offering tolerance to high salt concentrations, and an ability to make use of a wide variety of food sources. The genes were copied from bacteria that live in the same extreme environment as Galdieria.

"Why reinvent the wheel if you can copy it from your neighbor?" asks Lercher.

 

"It's usually assumed that organisms with a nucleus cannot copy genes from different species--that's why eukaryotes depend on sex to recombine their genomes. "How has Galdieria managed to overcome this limitation? It's an exciting question."

 

What Galdieria did is "a dream come true for biotechnology," says Weber.

"Galdieria has acquired genes with interesting properties from different organisms, integrated them into a functional network and developed unique properties and adaptations." In the future, genetic engineering may allow other algae to make use of the proteins that offer stress tolerance to Galdieria. Such a development would be relevant to biofuel production, says Schoenknecht, as oil-producing algae don't yet have the ability to withstand the same extreme conditions as Galdieria.

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NIST's prototype solid-state refrigerator uses quantum physics for extreme cooling to less than 1 Kelvin

NIST's prototype solid-state refrigerator uses quantum physics for extreme cooling to less than 1 Kelvin | Amazing Science | Scoop.it

Researchers at the National Institute of Standards and Technology (NIST) have demonstrated a solid-state refrigerator that uses quantum physics in micro- and nanostructures to cool a much larger object to extremely low temperatures.


What's more, the prototype NIST refrigerator, which measures a few inches in outer dimensions, enables researchers to place any suitable object in the cooling zone and later remove and replace it, similar to an all-purpose kitchen refrigerator. The cooling power is the equivalent of a window-mounted air conditioner cooling a building the size of the Lincoln Memorial in Washington, D.C.

 

"It's one of the most flabbergasting results I've seen," project leader Joel Ullom says. "We used quantum mechanics in a nanostructure to cool a block of copper. The copper is about a million times heavier than the refrigerating elements. This is a rare example of a nano- or microelectromechanical machine that can manipulate the macroscopic world."

 

The technology may offer a compact, convenient means of chilling advanced sensors below standard cryogenic temperatures—300 milliKelvin (mK), typically achieved by use of liquid helium—to enhance their performance in quantum information systems, telescope cameras, and searches for mysterious dark matter and dark energy.


The NIST refrigerator's cooling elements, consisting of 48 tiny sandwiches of specific materials, chilled a plate of copper, 2.5 centimeters on a side and 3 millimeters thick, from 290 mK to 256 mK. The cooling process took about 18 hours. NIST researchers expect that minor improvements will enable faster and further cooling to about 100 mK.

 

The cooling elements are sandwiches of a normal metal, a 1-nanometer-thick insulating layer, and a superconducting metal. When a voltage is applied, the hottest electrons "tunnel" from the normal metal through the insulator to the superconductor. The temperature in the normal metal drops dramatically and drains electronic and vibrational energy from the object being cooled.

 

NIST researchers previously demonstrated this basic cooling method** but are now able to cool larger objects that can be easily attached and removed. Researchers developed a micromachining process to attach the cooling elements to the copper plate, which is designed to be a stage on which other objects can be attached and cooled. Additional advances include better thermal isolation of the stage, which is suspended by strong, cold-tolerant cords.

 

Cooling to temperatures below 300 mK currently requires complex, large and costly apparatus. NIST researchers want to build simple, compact alternatives to make it easier to cool NIST's advanced sensors. Researchers plan to boost the cooling power of the prototype refrigerator by adding more and higher-efficiency superconducting junctions and building a more rigid support structure.


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Starry frog rediscovered after thought extinct for 160 years (photos)

Starry frog rediscovered after thought extinct for 160 years (photos) | Amazing Science | Scoop.it

In 1853 Edward Frederick Kelaart, a physician and naturalist, collected a strange frog on the island of Sri Lanka then a British colony known as Ceylon. The specimen was a large shrub frog (about 2 inches or 5.5 centimeters long) with black-outlined white specks on lime-green skin. He dubbed it "starry" after its pale specks, but that was last anyone heard of it. Even the holotype—the body of the amphibian collected by Kelaart—went missing. Fast forward nearly 160 years—two world wars, Sri Lanka's independence, and a man on the moon—when a recent expedition into Sri Lanka's Peak Wilderness rediscovered a beguiling frog with pinkish specks.

"These quite stunning frogs were observed perched on leaves in the canopy. They were slow moving, we collected samples which we thought were new species. But after reviewing past work, especially extinct species, it was evident that this was Pseudophilautus stellatus," L.J. Mendis Wickramasinghe told mongabay. Kelaart's starry shrub frog, or Pseudophilautus stellatus, had been re-discovered!

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