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MicroRNA-Target Binding Structures Mimic MicroRNA Duplex Structures in Humans

MicroRNA-Target Binding Structures Mimic MicroRNA Duplex Structures in Humans | Amazing Science |

MicroRNAs (miRNAs) have emerged as key gene regulators in diverse biological pathways. These small non-coding RNAs bind to target sequences in mRNAs, typically resulting in repressed gene expression. Traditionally, researchers match a microRNA guide strand to mRNA sequences using sequence comparisons to predict its potential target genes. However, many of the predictions can be false positives due to limitations in sequence comparison alone. In a recently published study, scientists consider the association of two related RNA structures that share a common guide strand: the microRNA duplex and the microRNA-target binding structure. They have analyzed thousands of such structure pairs and found many of them share high structural similarity. From this investigation, they conclude that when predicting microRNA target genes, considering just the microRNA guide strand matches to gene sequences may not be sufficient – The microRNA duplex structure formed by the guide strand and its companion passenger strand must also be considered. They have also developed software to translate RNA binding structure into encoded representations, and we have also created novel automatic comparison methods utilizing such encoded representations to determine RNA structure similarity. The presented software and methods can be utilized in the other RNA secondary structure comparisons as well.

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Making predictions about the multiverse

Making predictions about the multiverse | Amazing Science |

A recent conference organized by the Fundamental Questions Institute (FQXi) in Puerto Rico about making predictions in cosmology, especially in the eternally inflating multiverse. Many physicists and cosmologists are thinking with some “confidence” that we live in a multiverse, more specifically one of the many universes in which low-energy physical laws take different forms. For example, these universes have different elementary particles with different properties, possibly different spacetime dimensions, and so on. This idea of the multiverse is not simply a result of random imagination by theorists, but is based on several pieces of observational and theoretical evidence.

Observationally, we have learned more and more that we live in a highly special universe—it seems that the “physical laws” of our universe (summarized in the form of standard models of particle physics and cosmology) takes such a special form that if its structure were varied slightly, then there would be no interesting structure in the universe, let alone intelligent life. It is hard to understand this fact unless there are many universes with varying “physical laws,” and we simply happen to emerge in a universe which allows for intelligent life to develop (which seems to require special conditions). With multiple universes, we can understand the “specialness” of our universe precisely as we understand the “specialness” of our planet Earth (e.g. the ideal distance from the sun), which is only one of the many planets out there.

Perhaps more nontrivial is the fact that our current theory of fundamental physics leads to this picture of the multiverse in a very natural way. Imagine that at some point in the history of the universe, space is exponentially expanding. This expansion—called inflation—occurs when space is filled with a “positive vacuum energy”, which happens quite generally. We knew, already in 80′s, that such inflation is generically eternal. During inflation, various non-inflating regions called bubble universes—of which our own universe could be one—may form, much like bubbles in boiling water. Since ambient space expands exponentially, however, these bubbles do not percolate; rather, the process of creating bubble universes lasts forever in an eternally inflating background. Now, recent progress in string theory suggests that low energy theories describing phyics in these bubble universes (such as the elementary particle content and their properties) may differ bubble by bubble. This is precisely the setup needed to understand the “specialness” of our universe because of the selection effect associated with our own existence, as described above.

This particular version of the multiverse—called the eternally inflating multiverse—is very attractive. It is theoretically motivated and has a potential to explain various features seen in our universe. The eternal nature of inflation, however, causes a serious issue of predictivity. Because the process of creating bubble universes occurs infinitely many times, “In an eternally inflating universe, anything that can happen will happen; in fact, it will happen an infinite number of times,” as phrased in an article by Alan Guth.

The picture presented here does not solve all the problems in eternally inflating cosmology. What is the actual quantum state of the multiverse? What is its “initial conditions”? What is time? How does it emerge? The basic idea is that the state of the multiverse (which may be selected uniquely by the normalizability condition) never changes, and yet time appears as an emergent concept locally in branches as physical correlations among objects (along the lines of an old idea by DeWitt). 

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Redlight Special: Optogenetic Toolkit Goes Multicolor

Redlight Special: Optogenetic Toolkit Goes Multicolor | Amazing Science |
New light-sensitive proteins allow scientists to study how multiple sets of neurons interact with each other.

Optogenetics is a technique that allows scientists to control neurons’ electrical activity with light by engineering them to express light-sensitive proteins. Within the past decade, it has become a very powerful tool for discovering the functions of different types of cells in the brain.

Most of these light-sensitive proteins, known as opsins, respond to light in the blue-green range. Now, a team led by MIT has discovered an opsin that is sensitive to red light, which allows researchers to independently control the activity of two populations of neurons at once, enabling much more complex studies of brain function.

Opsins occur naturally in many algae and bacteria, which use the light-sensitive proteins to help them respond to their environment and generate energy.

To achieve optical control of neurons, scientists genetically modify brain cells of mice to express the gene for an opsin, which transports ions across the cell’s membrane to alter its voltage. Depending on the opsin used, shining light on the cell either lowers the voltage and silences neuron firing, or boosts voltage and provokes the cell to generate an electrical impulse. This effect is nearly instantaneous and easily reversible.

Using this approach, researchers can selectively turn a population of cells on or off and observe what happens in the brain. However, until now, they could activate only one population at a time, because the only opsins that responded to red light also responded to blue light, so they couldn’t be paired with other opsins to control two different cell populations.

To seek additional useful opsins, the MIT researchers worked with Gane Ka-Shu Wong, a professor of medicine and biological sciences at the University of Alberta, the paper’s other senior author. Wong’s team  is sequencing the transcriptomes of 1,000 plants, including some algae. (The transcriptome is similar to the genome but includes only the genes that are expressed by a cell, not the entirety of its genetic material.)

Once the team obtained genetic sequences that appeared to code for opsins, Klapoetke tested their light-responsiveness in mammalian brain tissue, working with Martha Constantine-Paton, an MIT professor of brain and cognitive sciences and of biology, a member of the McGovern Institute, and an author of the paper. The red-light-sensitive opsin, which the researchers named Chrimson, can mediate neural activity in response to light with a 735-nanometer wavelength.

The researchers also discovered a blue-light-driven opsin that has two highly desirable traits: It operates at high speed, and it is sensitive to very dim light. This opsin, called Chronos, can be stimulated with levels of blue light that are too weak to activate Chrimson.

Most optogenetic studies thus far have been done in mice, but Chrimson could be used for optogenetic studies of fruit flies, a commonly used experimental organism. Researchers have had trouble using blue-light-sensitive opsins in fruit flies because the light can get into the flies’ eyes and startle them, interfering with the behavior being studied.

Vivek Jayaraman, a research group leader at Janelia Farms and an author of the paper, was able to show that this startle response does not occur when red light is used to stimulate Chrimson in fruit flies.

Because red light is less damaging to tissue than blue light, Chrimson also holds potential for eventual therapeutic use in humans, Boyden says. Animal studies with other opsins have shown promise in helping to restore vision after the loss of photoreceptor cells in the retina.

The researchers are now trying to modify Chrimson to respond to light in the infrared range. They are also working on making both Chrimson and Chronos faster and more light sensitive.

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Why De-Extinction of Birds is a Challenge – The Passenger Pidgeon Case

Why De-Extinction of Birds is a Challenge – The Passenger Pidgeon Case | Amazing Science |

Birds are a huge challenge for de-extinction for two big reasons. The first is because less genomic research has been performed on birds than on mammals (but reptiles, amphibians, fish, invertebrates and plants are even less understood). We don’t know how precisely how the majority of gene pathways in birds work on the cellular levels and up.

Also, birds have no uterus. The reason that the absence of a uterus is a problem for cloning relates to how cloning is done. When you take the nucleus out of an egg cell you kill that cell, it is completely dead. Even after you put a new nucleus in it, the cell is still dead. You have to bring the cell back to life, just like when you shock someone’s heart into beating again. You run electricity through the newly cloned cell to get it to divide. The problem here is that you have to keep stimulating cell division for many generations, up to several hundred and even a few thousand cells before the embryo will develop on its own without assistance. Therefore you cannot take a single cloned cell and implant it into an ovary, oviduct, uterus or any reproductive organ and get it to grow – you have to grow it in the lab and then implant a partially developed embryo. This is okay in a uterus because the embryo implants and develops in a fixed place. In a bird, the embryo is in constant motion within the female’s body – literally tumbling down the oviduct as the oviduct coats the eggshell around the embryo. To implant a cloned embryo one would have to take out the developing embryo from within a developing hard shelled egg within the female’s body and replace it with the cloned embryo – and hope that the embryo integrates into the yolk of the egg and that all the puncturing doesn’t deform the egg or harm the female. So you can see it’s very very tricky.

Are there ways to introduce an extinct bird’s genetics into an embryo without cloning? You can introduce cells into the embryo, which will integrate and create a chimeric bird – a bird that has a patchwork of tissues made of cells of both the original embryo and the cells that were introduced. This can be done after the egg is laid, avoiding tampering with the mother’s internal organ systems. The problem for de-extinction is that adult stem cells (or induced Pluripotent Stem cells, iPCs) cannot contribute to the germ line, only Embryonic stem cells can contribute to the germ line. We can’t easily use embryonic stem cells to recreate the passenger pigeon genome. After as few as seven days in a lab culture, embryonic stem cells have undergone enough cell division to be adult stem cells, and lose the ability to become germ cells. A process to use embryonic stem cells would require introducing a mutation to a band-tailed pigeon embryonic stem cell in less than a matter of a few days, then put it into an embryo and hatch a chimera. This would then require hundreds to even thousands of generations of chimeric birds until we have a passenger pigeon. It would be far more efficient to introduce the thousands of mutations in cell lines, then create a bird. But by the time all the mutations were added, the cells would be adult stem cells. You could make as many chimeras as you want from these “de-extinct” stem cells, but they would never form a breeding line. This does not mean that stem cells cannot become germ cells under experimental conditions, what this means is that they do not naturally become germ cells when placed inside a developing bird embryo. It may be possible in the future to program iPSCs to become germ cells, but currently this is not possible.

Further reading: The Mammoth Cometh (NY Times)

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Quantum engineering pushes quantum absorption refrigerator beyond classical efficiency limits

Quantum engineering pushes quantum absorption refrigerator beyond classical efficiency limits | Amazing Science |

The laws of thermodynamics determine what is possible and impossible in classical systems. Lately, scientists have been working on establishing quantum analogues of these fundamental laws to determine the performance limits of quantum systems. Now in a new study, scientists have established the thermodynamic limits on quantum absorption refrigerators, and then somewhat counterintuitively show how quantum engineering techniques can push the refrigerators beyond these limits, resulting in superefficient cooling.

The findings show how quantum enhancements can allow quantum systems to exceed what is classically achievable, and marks a promising step toward the development of practical quantum cooling technologies. The researchers, Luis A. Correa, et al., from the University of La Laguna in Spain and the University of Nottingham in the UK, have published their paper on quantum-enhanced refrigeration in a recent issue of Nature Scientific Reports.

Whether classical or quantum in nature, refrigerators function by transporting energy from a cold reservoir (the object to be cooled) to a hot reservoir, usually with assistance from a power source or, in the case of an absorption refrigerator, an additional work reservoir.

"First patented by Einstein himself, absorption fridges are really 'cool,'" coauthor Gerardo Adesso at the University of Nottingham told "They refrigerate by absorbing heat from outside, without having to be plugged to a power socket. People use them, e.g., while camping, but these fridges have been traditionally hindered by quite a low cooling power." For any refrigerator, the efficiency of the refrigeration process cannot exceed the Carnot limit, or else it would violate the second law of thermodynamics.

In the new study, the scientists investigated the theoretical maximum efficiency of a quantum refrigerator operating at maximum power. Efficiency at maximum power is of greater practical interest than efficiency in general, since power vanishes at high efficiencies. Here, the scientists proved that the efficiency at maximum power of a quantum refrigerator of any kind is limited by a fraction of the Carnot limit.

"Discovering that all quantum absorption fridges admit a tight model-independent performance limit was indeed surprising," Adesso said. "Establishing these bounds on efficiency at maximum power for heat engines and refrigerators has been a long-standing problem in finite-time thermodynamics."

Although this limit holds for all models of quantum absorption refrigerators, it is not the final answer. In the second part of their paper, the researchers show that quantum refrigerators can boost their performance by exploiting the system's quantum features.

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A detailed map of Jupiter's moon Ganymede, which might be habitable one day

A detailed map of Jupiter's moon Ganymede, which might be habitable one day | Amazing Science |

One day, poor planet Earth will succumb to the centuries of abuse we've dealt her, shrivel up, and cease to support life. Then, if we're not already living in some Elysium-like habitat in space, we'll have to find a new home. Jupiter's moon, Ganymede, might just be it.

Ganymede with its underground ocean and rocky terrain is already being eyed by scientists as one of the solar system's few habitable environments. Until now, though, we haven't known exactly what was on that far away satellite which also happens to be the largest moon in our solar system. Thankfully, a team of Brown scientists and geologists fixed that problem by making this terrifically detailed map of Ganymede using images from NASA's Voyager and Galileo missions.

The map is a little intimidating at first, but once you delve into it, you'll realize that exploring the geography of Ganymede isn't so different from exploring the geography of Earth. Different colors represent the different elements that make up the moon's surface creating an almost marbled look as the minerals run together. Of course, Ganymede would need a little work before we can colonize it. But let's just hope we never have to.

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Microrobotic technique combines 3D printing and tissue engineering

Microrobotic technique combines 3D printing and tissue engineering | Amazing Science |

Researchers at Brigham and Women's Hospital (BWH) and Carnegie Mellon University have introduced a unique micro-robotic technique to assemble the components of complex materials, the foundation of tissue engineering and 3D printing, described in the Jan. 28, 2014, issue of Nature Communications ("Untethered micro-robotic coding of three-dimensional material composition").

Tissue engineering and 3D printing have become vitally important to the future of medicine for many reasons. The shortage of available organs for transplantation, for example, leaves many patients on lengthy waiting lists for life-saving treatment. Being able to engineer organs using a patient's own cells can not only alleviate this shortage, but also address issues related to rejection of donated organs. Developing therapies and testing drugs using current preclinical models have limitations in reliability and predictability. Tissue engineering provides a more practical means for researchers to study cell behavior, such as cancer cell resistance to therapy, and test new drugs or combinations of drugs to treat many diseases.

The presented approach uses untethered magnetic micro-robotic coding for precise construction of individual cell-encapsulating hydrogels (such as cell blocks). The micro-robot, which is remotely controlled by magnetic fields, can move one hydrogel at a time to build structures. This is critical in tissue engineering, as human tissue architecture is complex, with different types of cells at various levels and locations. When building these structures, the location of the cells is significant in that it will impact how the structure will ultimately function. "Compared with earlier techniques, this technology enables true control over bottom-up tissue engineering," explains Tasoglu.

Tasoglu and Demirci also demonstrated that micro-robotic construction of cell-encapsulating hydrogels can be performed without affecting cell vitality and proliferation. Further benefits may be realized by using numerous micro-robots together in bioprinting, the creation of a design that can be utilized by a bioprinter to generate tissue and other complex materials in the laboratory environment."

Our work will revolutionize three-dimensional precise assembly of complex and heterogeneous tissue engineering building blocks and serve to improve complexity and understanding of tissue engineering systems," said Metin Sitti, professor of Mechanical Engineering and the Robotics Institute and head of CMU's NanoRobotics Lab.

"We are really just beginning to explore the many possibilities in using this micro-robotic technique to manipulate individual cells or cell-encapsulating building blocks." says Demirci. "This is a very exciting and rapidly evolving field that holds a lot of promise in medicine."

Deborah Verran's curator insight, February 14, 2014 10:07 PM

Another interesting step in the research that is being performed in the tissue engineering sphere. However there is a lot more research required before bioengineered tissues can be used for transplantation into humans

Sieg Holle's curator insight, February 16, 2014 11:23 AM

Towards our age of abundance and self sufficiency and personal choice?

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Lockheed Martin joins the world's largest wave-energy development project

Lockheed Martin joins the world's largest wave-energy development project | Amazing Science |

Lockheed Martin has joined a partnership to develop what it described as “the world’s largest wave energy project” to date, off the Victoria coast in southern Australia. Victorian Wave Partners Ltd. is an Australian special-purpose company owned by Ocean Power Technologies Australasia Pty Ltd., a developer of “wave energy” technology.

OPT’s PowerBuoy system uses a "smart" buoy to convert wave energy into electricity.  The buoy moves up and down with the rising and falling of waves, and the mechanical energy generated by this action drives an electrical generator, which transmits power to shore via an underwater cable.

The system is designed to be electrically tuned on a wave-by-wave basis to maximize the amount of electricity produced. In the Australian development, anticipated peak-power generating capacity is 62.5 megawatts. That would be sufficient to supply 10,000 homes.

The Victorian Wave project is scheduled to be built in three stages, with the first stage producing approximately 2.5 megawatts of peak power.

No starting date has been indicated for the installation.

Lockheed did not reveal the value of its investment.  It will provide overall project management, assist with the design for manufacturing the PowerBuoy systems, lead the production of selected components, and perform system integration of the wave energy converters.

Lockheed Martin’s participation in this project is reminiscent of Boeing’s recent participation in a tidal-energy project, though wave power is distinct from tidal power.

Wave power devices extract energy from the surface motion of ocean waves, which is very predictable and reportedly will generate electricity for more hours in a year than wind and solar sources.

"We are applying our design and system integration expertise to commercialize promising, emerging alternative energy technologies, including ocean power," stated Tim Fuhr, director of ocean energy for Lockheed Martin's Mission Systems and Training business. "This project extends our established relationship with OPT and Australian industry, and enables us to demonstrate a clean, efficient energy source for Australia and the world."

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Predictable Lifespan: Worm Study Suggests that Mitochondrial Activity Determines Aging

Predictable Lifespan: Worm Study Suggests that Mitochondrial Activity Determines Aging | Amazing Science |

Scientists have a crystal ball on their hands: bursts of activity in the energy-producing mitochondria in a worm’s cells accurately predict how long it will live. The findings, published in Nature1, suggest that an organism’s lifespan is, for the most part, predictable in early adulthood. Unlike other biomarkers for aging, which work under limited conditions, these mitochondrial bursts are a stable predictor for a variety of genetic, environmental and developmental histories.

“Mitochondrial flashes have an amazing power to predict the remaining lifespan in animals,” says study lead Meng-Qiu Dong, a geneticist who studies aging in the Caenorhabditis elegans worm at the National Institute of Biological Sciences in Beijing. “There is truth in the mitochondrial theory of aging.”

The mitochondria are organelles that power the cells of plants, animals and other eukaryotic organisms. During energy production, they produce reactive oxygen molecules, such as free radicals, that can cause stress and damage the mitochondria. Although mitochondria break down over time, the mitochondrial theory of aging, first proposed2 in 1972, remains controversial and unproven. For instance, some long-lived organisms, such as naked mole rats, endure with high levels of oxidative damage. Nevertheless, many scientists think that mitochondria remain the primary drivers of aging.

Dong became interested in the 2008 discovery3 that mitochondria produce reactive oxygen molecules in 10-second pulses — ‘mitoflashes’ — every couple minutes. For the first time, scientists could observe individual mitochondria and their rates of activity through the course of an animal’s life. In this study, Dong initially compared mitoflash rates in short-lived C. elegans worms, which live an average of 21 days, to long-lived worms that live an average of 30 days or more. She found that, in all of the animals, there were two moments in life when mitoflashes bunched closely together: one burst during early adulthood and another during senescence.

At first, she expected that the burst later in life would be the important one. “It was a total failure,” she says. Instead, it was the early burst that revealed a correlation between flash frequency and lifespan: worms with an average lifespan of 21 days had more frequent flashes during this burst than their longer-lived brethren. The correlation held across 29 genetic mutants with various lifespans. Mitoflashes also proved to be a powerful record of a worm’s early life experiences. For instance, worms exposed to heat shock or starvation tend to have longer lives, and predictably, their mitoflashes occurred at longer intervals. Even genetically identical worms that had different lifespans due to chance events alone showed the same correlation between mitoflash frequency and longevity. The most striking finding came when Dong treated a long-lived worm to increase its production of reactive oxygen molecules. This shortened the worm’s life and increased the rate of mitoflashes.

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Scientists Say Their Giant Laser Has For The First Time Produced Nuclear Fusion

Scientists Say Their Giant Laser Has For The First Time Produced Nuclear Fusion | Amazing Science |

Researchers at a laboratory in California say they've had a breakthrough in producing fusion power with a giant laser. The success comes after years of struggling to get the laser to work, and is another step in the decades-long quest for fusion energy. Omar Hurricane, a researcher at Lawrence Livermore National Laboratory, says that for the first time, they've produced significant amounts of fusion by zapping a target with their laser. "We've gotten more energy out of the fusion fuel than we put into the fusion fuel," he says.

Strictly speaking, while more energy came from fusion than went into the hydrogen fuel, only about 1 percent of the laser's energy ever reached the fuel. Useful levels of fusion are still a long way off. "They didn't get more fusion power out than they put in with the laser," says Steve Cowley, the head of a huge fusion experiment in the U.K. called the Joint European Torus, or JET.

The laser is known as the National Ignition Facility, or NIF. Constructed at a cost of more than $3 billion, it consists of 192 beams that take up the length of three football fields. For a brief moment, the beams can focus 500 trillion watts of power — more power than is being used in that same time across the entire United States — onto a target about the width of a No. 2 pencil.

The goal is fusion. Fusion is a process where hydrogen atoms are squeezed together to make helium atoms. When that happens, a lot of energy comes out. It could mean the answer to the world's energy problems, but fusion is really, really hard to do. Hurricane says that each time they try, it feels like they're taking a test.

"Of course you want to score real well, you think you've learned the material, but you just have to see how you do," he says.

Over the past few years, NIF has been getting a fat "F." For all its power, it just couldn't get the hydrogen to fuse, and researchers didn't know why. The failures have led NIF's critics to label the facility an enormous waste of taxpayer dollars. In 2012, the government shifted NIF away from its fusion goals to focus on its other mission: simulating the conditions inside nuclear weapons.

But the fusion experiments continued, and Hurricane says researchers now understand why their original strategy wasn't working. In the journal Nature, he and his colleagues report that they've finally figured out how to squeeze the fuel with the lasers. By doing a lot of squeezing right at the start, they were able to keep the fuel from churning and squirting out. The lasers squeezed evenly and the hydrogen turned into helium. The new technique can't reach "ignition," which is the point at which the hydrogen fusion feeds on itself to make more. Even so, JET's Cowley says, this is still a big moment for NIF.

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Truncated guide RNAs drastically improve specificity of CRISPR-Cas nucleases

Truncated guide RNAs drastically improve specificity of CRISPR-Cas nucleases | Amazing Science |
A simple adjustment to a powerful gene-editing tool may be able to improve its specificity. Investigators have found that adjusting the length of the the guide RNA component of the synthetic enzymes called CRISPR-Cas RNA-guided nucleases can substantially reduce the occurrence of off-target DNA mutations.

Clustered, regularly interspaced, short palindromic repeat (CRISPR) RNA-guided nucleases (RGNs) are highly efficient genome editing tools123. CRISPR-associated 9 (Cas9) RGNs are directed to genomic loci by guide RNAs (gRNAs) containing 20 nucleotides that are complementary to a target DNA sequence. However, RGNs can induce mutations at sites that differ by as many as five nucleotides from the intended target456. A research team recently reports that truncated gRNAs, with shorter regions of target complementarity <20 nucleotides in length, can decrease undesired mutagenesis at some off-target sites by 5,000-fold or more without sacrificing on-target genome editing efficiencies. In addition, use of truncated gRNAs can further reduce off-target effects induced by pairs of Cas9 variants that nick DNA (paired nickases). These results delineate a simple, effective strategy to improve the specificities of Cas9 nucleases or paired nickases.

"Simply by shortening the length of the gRNA targeting region, we saw reductions in the frequencies of unwanted mutations at all of the previously known off-target sites we examined," says J. Keith Joung, MD, PhD, associate chief for Research in the MGH Department of Pathology and senior author of the report. "Some sites showed decreases in mutation frequency of 5,000-fold or more, compared with full length gRNAs, and importantly these truncated gRNAs -- which we call tru-gRNAs -- are just as efficient as full-length gRNAs at reaching their intended target DNA segments."

CRISPR-Cas RGNs combine a gene-cutting enzyme called Cas9 with a short RNA segment and are used to induce breaks in a complementary DNA segment in order to introduce genetic changes. Last year Joung's team reported finding that, in human cells, CRISPR-Cas RGNs could also cause mutations in DNA sequences with differences of up to five nucleotides from the target, which could seriously limit the proteins' clinical usefulness. The team followed up those findings by investigating a hypothesis that could seem counterintuitive, that shortening the gRNA segment might reduce off-target mutations.

"Some of our experiments from last year suggested that one could mismatch a few nucleotides at one end of the gRNA complementarity region without affecting the targeting activity," Joung explains. "That led us to wonder whether removing these nucleotides could make the system more sensitive to mismatches in the remaining sequence."

Based on a natural system a species of bacteria uses against other pathogens, the CRISPR-Cas RGNs most widely used by researchers includes a 20-nucleotide targeting region within the gRNA. To test their theory, the MGH team constructed RGNs with progressively shorter gRNAs and found that, while gRNAs with targeting segments of 17 or 18 nucleotides were as or more efficient than full-length gRNAs in reaching their targets, those with 15- or 16-nucleotide targeting segments had reduced or no targeting activity. Subsequent experiments found that 17-nucleotide truncated RGNs efficiently induced the desired mutations in human cells with greatly reduced or undetectable off-target effects, even at sites with only one or two mismatches.

"While we don't fully understand the mechanism by which tru-gRNAs reduce off-target effects, our hypothesis is that the original system might have more energy than it needs, enabling it to cleave even imperfectly matched sites," says Joung, who is an associate professor of Pathology at Harvard Medical School. "By shortening the gRNA, we may reduce the energy to a level just sufficient for on-target activity, making the nuclease less able to cleave off-target sites. But more work is needed to define exactly why tru-gRNAs have reduced off-target effects."

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Wobbly Alien Planet with Wild Seasons Found by NASA Telescope

Wobbly Alien Planet with Wild Seasons Found by NASA Telescope | Amazing Science |

Astronomers have discovered an alien planet that wobbles at such a dizzying rate that its seasons must fluctuate wildly. Throughout all of the planet's fast-changing seasons, however, no forecast would be friendly to humans. The warm planet is a gassy super-Neptune that orbits too close to its two parent stars to be in its system's "habitable zone," the region where temperatures would allow liquid water, and perhaps life as we know it, to exist.

The faraway world, which lies 2,300 light-years away in the constellation Cygnus, was discovered by NASA's planet-hunting Kepler space telescope. Dubbed Kepler-413b, the planet orbits a pair of orange and red dwarf stars every 66 days. [A World of Kepler Planets]

Kepler was designed to detect exoplanets by noticing the dips in brightness caused when these worlds transit, or cross in front of, their parent stars. Normally these transits occur in a regular pattern, but Kepler-413b behaved strangely.

"What we see in the Kepler data over 1,500 days is three transits in the first 180 days (one transit every 66 days), then we had 800 days with no transits at all," study lead investigator Veselin Kostov, of the Space Telescope Science Institute and Johns Hopkins University, said in a statement. "After that, we saw five more transits in a row."

Kostov and colleagues concluded that the planet's wobble must be causing it to move up or down relative to our view, so much so that it sometimes doesn't appear to cross in front of its parent stars. A NASA statement compared the planet's motions to a child's spinning top on the rim of a wobbling bicycle wheel rotating on its side.

The scientists determined that the planet's axial tilt can vary by as much as 30 degrees over 11 years,. For comparison, Earth's tilt has shifted 23.5 degrees over 26,000 years. The researchers say it's amazing that this planet is wobbling, or precessesing, so much on a human time scale, and they say it's possible that there are other planets like Kepler-413b awaiting discovery.

"Presumably there are planets out there like this one that we're not seeing because we're in the unfavorable period," Peter McCullough, a team member from STScI and JHU, said in a statement.

Kostov and colleagues are still investigating what causes the extreme wobble of the gas planet, which has a mass about 65 times that of Earth. They say Kepler-413b's orbit may have been tilted by other planets in the system or by a nearby star exerting gravitational influence.

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New study examines thousands of brains to reveal differences between male and female brain structure

New study examines thousands of brains to reveal differences between male and female brain structure | Amazing Science |

Reviewing over 20 years of neuroscience research into sex differences in brain structure, a Cambridge University team has conducted the first meta-analysis of the evidence, published this week in the prestigious journal Neuroscience and Biobehavioral Reviews

The team, led by doctoral candidate Amber Ruigrok and Professors John Suckling and Simon Baron-Cohen in the Department of Psychiatry, performed a quantitative review of the brain imaging literature testing overall sex differences in total and regional brain volumes. They searched all articles published between 1990 and 2013. A total of 126 articles were included in the study, covering brains from individuals as young as birth to 80 years old.

They found that males on average have larger total brain volumes than women (by 8-13%). On average, males had larger absolute volumes than females in the intracranial space (12%; >14,000 brains), total brain (11%; 2,523 brains), cerebrum (10%; 1,851 brains), grey matter (9%; 7,934 brains), white matter (13%; 7,515 brains), regions filled with cerebrospinal fluid (11.5%; 4,484 brains), and cerebellum (9%; 1,842 brains). Looking more closely, differences in volume between the sexes were located in several regions. These included parts of the limbic system, and the language system.

Specifically, males on average had larger volumes and higher tissue densities in the left amygdala, hippocampus, insular cortex, putamen; higher densities in the right VI lobe of the cerebellum and in the left claustrum; and larger volumes in the bilateral anterior parahippocampal gyri, posterior cingulate gyri, precuneus, temporal poles, and cerebellum, areas in the left posterior and anterior cingulate gyri, and in the right amygdala, hippocampus, and putamen.

By contrast, females on average had higher density in the left frontal pole, and larger volumes in the right frontal pole, inferior and middle frontal gyri, pars triangularis, planum temporale/parietal operculum, anterior cingulate gyrus, insular cortex, and Heschl’s gyrus; bilateral thalami and precuneus; the left parahippocampal gyrus, and lateral occipital cortex.

The results highlight an asymmetric effect of sex on the developing brain. Amber Ruigrok, who carried out the study as part of her PhD, said: “For the first time we can look across the vast literature and confirm that brain size and structure are different in males and females. We should no longer ignore sex in neuroscience research, especially when investigating psychiatric conditions that are more prevalent in either males or females.”

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Bonobos, like humans, keep time to music, study shows

Bonobos, like humans, keep time to music, study shows | Amazing Science |

Some animals, like humans, can sense and respond to a musical beat, a finding that has implications for understanding how the skill evolved, scientists said. A study of bonobos, closely related to chimpanzees, shows they have an innate ability to match tempo and synchronize a beat with human experimenters. For the study, researchers designed a highly resonate, bonobo-friendly drum able to withstand 500 pounds of jumping pressure, chewing, and other ape-like behaviors.

“Bonobos are very attuned to sound. They hear above our range of hearing,” said Patricia Gray, a biomusic program director at University of North Carolina in Greensboro. Experimenters beat a drum at a tempo favored by bonobos – roughly 280 beats per minute, or the cadence that humans speak syllables. The apes picked up the beat and synchronized using the bonobo drum, Gray and psychologist Edward Large, with the University of Connecticut, said at the annual meeting of the American Association for the Advancement of Science.

“It’s not music, but we’re slowing moving in that direction,” Large said. Related research on a rescued sea lion, which has no innate rhythmic ability, shows that with training, it could bob its head in time with music, said comparative psychologist Peter Cook, who began working with Ronan the sea lion while a graduate student at the University of California, Santa Cruz.

Scientists suspect that the musical and rhythmic abilities of humans evolved to strengthen social bonds, “so, one might think that a common ancestor to humans and the bonobo would have some of these capabilities,” Large said. The addition of sea lions to the list suggests that the ability to sense rhythm may be more widespread.

Gray and Large said they would like to conduct a study on whether bonobos in the wild synchronize with other members of their species when they, for example, beat on hollow trees.

“That’s really coordination. Now, you’re talking about a social interaction,” Large said. “If your brain rhythms are literally able to synchronize to someone else’s brain rhythms, that’s what communication is potentially all about.”

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Chaohusaurus Fossil Shows Oldest Live Reptile Birth

Chaohusaurus Fossil Shows Oldest Live Reptile Birth | Amazing Science |

Recent excavations in south Majiashan, Anhui, China, yielded more than 80 new ichthyosaur skeletons. Among the specimens was a partial skeleton that contained embryos. According to Dr. Chen and colleagues, the fossil belongs to the ichthyosaur Chaohusaurus, which is the oldest of Mesozoic marine reptiles. This viviparous creature lived around 248 million years ago. It had a lizard-like appearance and was one of the smallest ichthyosaurs (up to 1.8 m long).

The new fossil was associated with three embryos and neonates: one inside the mother, another exiting the pelvis-with half the body still inside the mother-and the third outside of the mother. The headfirst birth posture of the second embryo indicates that live births in ichthyosaurs may have taken place on land, instead of in the water, as some studies have previously suggested.

“The study reports the oldest vertebrate fossil to capture the ‘moment’ of live-birth, with a baby emerging from the pelvis of its mother. The 248-million-year old fossil of an ichthyosaur suggests that live-bearing evolved on land and not in the sea,” said Dr Ryosuke Motani from the University of California, Davis, the first author of a paper published in the journal PLoS ONE.

The Chaohusaurus fossil may also contain the oldest fossil embryos of Mesozoic marine reptile, about 10 million years older than those indicated on previous records.

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The Ubi Ubiquitous Computer is Here: Talk to Your Wall and Your Wall will Talk Back

The Ubi Ubiquitous Computer is Here: Talk to Your Wall and Your Wall will Talk Back | Amazing Science |

The Ubi is a WiFi-connected, voice-operated computer that plugs into a power outlet and makes the environment around it Internet enabled. Reminiscent of voice controlled computers depicted in science fiction, early uses of the Ubi include Internet search, messaging, and communications without the use of hands or screens. The Ubi also includes sensors that allow for remote monitoring of the environment around it.

Project Ubi Odyssey will allow early adopters of technology to get access to the Ubi, develop connectivity with home automation and Internet services, and create novel human computer interactions. Those interested can register for the program at and selected candidates will be invited to participate in the program. The Beta Ubi cost is $299. The program is currently limited to 5,000 participants and to residents of the United States.

The Ubi relies on powerful server technology that processes natural language to infer requests from the user and then pulls data from various Internet sources. Users can easily build voice-driven interactions and connect devices and services through the Ubi Portal. The device is equipped with temperature, humidity, air pressure and ambient light sensors to provide feedback on the environment around it. Also onboard the Ubi are stereo speakers, two microphones, and bright multi-colored LED indicator lights.

Unified Computer Intelligence Corporation CEO Leor Grebler told me the device will also be able to sense devices that are openly connected to the Internet (eventually, the Nest “learning” thermostat and smart smoke/CO2 alarms), “but we’re not controlling devices outright yet. We will add a way to talk to devices/Internet services as well as for them to talk back to the user.”

Here are the impressive specs: Android OS 4.1, 1.6 GHz Dual-Core ARM Cortex-A9 Processor, 1 GB RAM, 802.11 b/n/g Wifi Enabled (WPA and WPA2 encryption), stereo speakers and dual microphones, Bluetooth-capable, ambient light sensor, cloud-based speech recognition (Google/Android libraries), and natural language understanding.

And you can program its user interface on a computer, or verbally on the Ubi, Grebler said. “We’re slowly releasing apps on,” he said. “We have the first blossoms of an API that will essentially allow any Internet service, such as email, calendar, Twitter, Facebook, etc. ) to have its own voice and be interactive through the Ubi.”

You can register for the program at and selected candidates will be invited to participate in the program. The Beta Ubi cost is $299. The program is currently limited to 5,000 participants and to U.S. residents.

Tamika Garay's curator insight, March 25, 2015 11:24 PM

#4 Most Important Technologies in the next 5-10 years

Voice operated computers


Voice operated computers and operating systems have captured the imaginations of  sci-fi writers for years and have been included in recent works such as :


* Her (Movie, 2013 Director & Writer – Spike Jonze) - a movie about a man who falls in love with his interactive operating system.


* Extant (Series – 2014 Halle Berry) – there is a Siri-like talking computer device in every home and space station


Using voice commands to operate computers would make it more natural for humans to use by allowing the interface between user and computer become invisible. With the popularity of Siri and Google voice recognition, voice operated computers and operating systems will be important in the next 5-10 years.

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Quarks Know Their Left From Their Right

Quarks Know Their Left From Their Right | Amazing Science |

Matter interacts through four fundamental forces: the electromagnetic force that creates light and chemical bonds, the strong nuclear force that binds quarks and nuclei, the weak nuclear force that produces a type of radioactive decay called beta decay, and gravity. There could be other forces – some theorists have speculated that a second version of the weak force may also exist. At one time, physicists assumed that all the forces obeyed a handful of symmetries. So, for example, a physical system should behave exactly like its mirror image, a symmetry known as parity.

In 1957, physicists discovered that parity does not hold in particle interactions mediated by the weak force. For example, suppose you aim right-spinning electrons at nuclei and watch them bounce off. If you look at the tiny shooting gallery in a mirror, you'll see left-spinning electrons bouncing off the target. So if the interaction between electron and nucleus were mirror-symmetric, then the scattering of right- and left-spinning electrons should be the same. And, indeed, that’s exactly what would happen if the negatively charged electrons interacted with the positively charged nuclei only through the electromagnetic force.

But the electrons also interact with the nuclei through the weak force, which violates parity and is not mirror symmetric. As a result, right-spinning and left-spinning electrons ricochet off the target differently, creating a slight asymmetry in their scattering pattern. That effect was seen at SLAC National Accelerator Laboratory in Menlo Park, California, in 1978 in an experiment called E122 that helped cement physicists' then-emerging standard model. A second weak force, if it exists, ought to give similarly lopsided results.

But what about the quarks? Like electrons, they can spin one way or the other as they zip around inside protons and neutrons. And, according to the standard model, the right- and left-spinning quarks should interact slightly differently with an incoming electron, producing an additional asymmetry, or parity violation, when the spin of the incoming electrons is flipped. Now, Xiaochao Zheng, a nuclear physicist at the University of Virginia in Charlottesville, and colleagues have observed that smaller contribution, as they recently reported in Nature.

That was no mean feat. To see the extra asymmetry, the incoming electron must strike the nucleus hard enough to blast out a single quark, setting off a shower of particles, as was done in E122 but not in subsequent experiments. Researchers must take great care to ensure that they alternately shine equally intense beams of right- and left-spinning electrons on the target. Using the electron accelerator at Thomas Jefferson National Accelerator Facility in Newport News, Virginia, the researchers shined 170 billion electrons on a target of liquid deuterium over 2 months in 2009. After crunching the data, they were able to measure the part-in-10,000 scattering asymmetry precisely enough to pull out the contribution from the quarks, albeit with a large uncertainty. The result agrees with the standard model prediction.

"They've measured something fundamental at the quark level that wasn't measured before," says William Marciano, a theorist at Brookhaven National Laboratory in Upton, New York. Maas notes that the result is not as exciting as it could have been, however. "They have not observed any new physics at the level of their precision," he says. The new result does place tighter limits on models that assume a second weak force exists, Maas says.

The measurement is not the end of the road. The 101 members in the experimental team intend to repeat their measurement and hope to improve their precision by at least a factor of 5, Zheng says. That should enable them to test for new forces with far more sensitivity, she says. Marciano agrees that "this is just the first step." He notes that it might be beneficial that the asymmetry from the quarks is so small in the standard model, as that will make any deviation look relatively large.

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Scientists estimate 16,000 tree species in the Amazon

Scientists estimate 16,000 tree species in the Amazon | Amazing Science |
Researchers, taxonomists, and students from The Field Museum and 88 other institutions around the world have provided new answers to two simple but long-standing questions about Amazonian diversity: How many trees are there in the Amazon, and how many tree species occur there?

The vast extent and difficult terrain of the Amazon Basin (including parts of Brazil, Peru, Columbia) and the Guiana Shield (Guyana, Suriname, and French Guiana), which span an area roughly the size of the 48 contiguous North American states, has historically restricted the study of their extraordinarily diverse tree communities to local and regional scales. The lack of basic information about the Amazonian flora on a basin-wide scale has hindered Amazonian science and conservation efforts.

over 100 experts have contributed data from 1,170 forestry surveys in all major forest types in the Amazon to generate the first basin-wide estimates of the abundance, frequency and spatial distribution of thousands of Amazonian trees.

Extrapolations from data compiled over a period of 10 years suggest that greater Amazonia, which includes the Amazon Basin and the Guiana Shield, harbors around 390 billion individual trees, including Brazil nut, chocolate, and açai berry trees.

"We think there are roughly 16,000 tree species in Amazonia, but the data also suggest that half of all the trees in the region belong to just 227 of those species! Thus, the most common species of trees in the Amazon now not only have a number, they also have a name. This is very valuable information for further research and policymaking," says Hans ter Steege, first author on the study and researcher at the Naturalis Biodiversity Center in South Holland, Netherlands.

The authors termed these species "hyperdominants." While the study suggests that hyperdominants -- just 1.4 percent of all Amazonian tree species -- account for roughly half of all carbon and ecosystem services in the Amazon, it also notes that almost none of the 227 hyperdominant species are consistently common across the Amazon. Instead, most dominate a region or forest type, such as swamps or upland forests.

The study also offers insights into the rarest tree species in the Amazon. According to the mathematical model used in the study, roughly 6,000 tree species in the Amazon have populations of fewer than 1,000 individuals, which automatically qualifies them for inclusion in the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. The problem, say the authors, is that these species are so rare that scientists may never find them.

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Out of this world first light images emerge as the Gemini Planet Imager in Chile goes online

Out of this world first light images emerge as the Gemini Planet Imager in Chile goes online | Amazing Science |

After nearly a decade of development, construction and testing, the world's most advanced instrument for directly imaging and analyzing planets orbiting around other stars is pointing skyward and collecting light from distant worlds. 

"Even these early first-light images are almost a factor of 10 better than the previous generation of instruments. In one minute, we were seeing planets that used to take us an hour to detect," says Bruce Macintosh of Lawrence Livermore National Laboratory, who led the team who built the instrument. 

For the past decade, Lawrence Livermore has been leading a multi-institutional team in the design, engineering, building and optimization of the instrument, called the Gemini Planet Imager (GPI), which will be used for high-contrast imaging to better study faint planets or dusty disks next to bright stars. Astronomers -- including a team at LLNL-- have made direct images of a handful of extrasolar planets by adapting astronomical cameras built for other purposes. GPI is the first fully optimized planet imager, designed from the ground up for exoplanet imaging deployed on one of the world's biggest telescopes, the 8-meter Gemini South telescope in Chile.

Gemini Planet Imager's first light image (see picture) of the light scattered by a disk of dust orbiting the young star HR4796A. This narrow ring is thought to be dust from asteroids or comets left behind by planet formation; some scientists have theorized that the sharp edge of the ring is defined by an unseen planet. The left image shows normal light, including both the dust ring and the residual light from the central star scattered by turbulence in the Earth's atmosphere. The right image shows only polarized light. Leftover starlight is unpolarized and hence removed from this image. The light from the back edge of the disk is strongly polarized as it scatters towards us.

Gemini's website:

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Mechanical Overlords: AI Robots are Infiltrating Insect, Fish and Bird Communities and Take Control

Mechanical Overlords: AI Robots are Infiltrating Insect, Fish and Bird Communities and Take Control | Amazing Science |

Several years ago, a group of American cockroaches discovered four strangers in their midst. A brief investigation revealed that the interlopers smelled like cockroaches, and so they were welcomed into the cockroach community. The newcomers weren’t content to just sit on the sidelines, however. Instead, they began to actively shape the group’s behavior. Nocturnal creatures, cockroaches normally avoid light. But when the intruders headed for a brighter shelter, the rest of the roaches followed.

What the cockroaches didn’t seem to realize was that their new, light-loving leaders weren’t fellow insects at all. They were tiny mobile robots, doused in cockroach pheromones and programmed to trick the living critters into following their lead. The demonstration, dubbed the LEURRE project and conducted by a team of European researchers, validated a radical idea—that robots and animals could be merged into a “biohybrid” society, with biological and technological organisms forming a cohesive unit.

A handful of scientists have now built robots that can socially integrate into animal communities. Their goal is to create machines that not only infiltrate animal groups but also influence them, changing how fish swim, birds fly, and bees care for their young. If the research reaches the real world, we may one day use robots to manage livestock, control pests, and protect and preserve wildlife. So, dear furry and feathered friends, creepy and crawly creatures of the world: Prepare for a robo-takeover.

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Atomic circuits move a step closer – Memory effect seen for the first time in a cloud of ultracold atoms

Atomic circuits move a step closer – Memory effect seen for the first time in a cloud of ultracold atoms | Amazing Science |

A memory effect that is crucial in electronics has been seen for the first time in a cloud of ultracold atoms. The phenomenon represents a milestone in the emerging field of ‘atomtronics’, which seeks to create a whole new class of devices that use the flow of atoms, rather than electrons, in a circuit.

In atomtronics, clouds of atoms are super-cooled to form a collective quantum state known as a Bose-Einstein condensate (BEC). So far, physicists have used these atoms in analogues of basic electrical components such as transistors1and capacitors2. Such condensates can also become a superfluid — meaning atoms can flow past obstacles without friction — and be set in motion, circulating inside a ring-shaped trap.

Atomtronics has so far been largely theoretical, but it holds potential for developing entirely new quantum devices, says Gretchen Campbell, a physicist at the University of Maryland in College Park. Publishing in Nature3, her team is the first to directly see an effect known as hysteresis in an atomtronic circuit. Hysteresis is the dependence of a system not just on its current state, but also on its history.

A thermostat, for example, might turn a heating system off as the temperature rises to 21 °C, but will not turn it on again until it falls below 18 °C. This prevents small disturbances from causing big changes.

Magnetic hard drives, which store data in 0s and 1s, also exploit hysteresis: turning on a magnetic field can turn a 0 into a 1, but you need to do more than just remove the field to reverse the effect. “We don’t yet know exactly what these atomtronic devices would be,” Campbell says. “But in any real circuit you need hysteresis — something that acts like a memory or a filter."

"This work is really interesting, because it puts all the components of atomtronics together, studying collective behaviour of atoms and memory effects," says Shan-Wen Tsai, a physicist at the University of California, Riverside.

Atomtronics will not directly replace electronics, because atomic circuits are slower and bigger than their zippy electron counterparts. "You wouldn’t put a billion atomtronics components on a chip," Tsai adds.

But the atomtronic circuit could be useful in applications such as rotation sensors, playing the part that gyroscopes have in spacecraft and aeroplane navigation. The devices could also some day perform rudimentary quantum computations, says Ludwig Mathey, a theoretical physicist at the University of Hamburg in Germany, who works on simulating ultracold atom systems. Future 'quantum computers' promise to perform certain tasks exponentially faster than any traditional computer ever could. “ BECs have the advantage of being more robust than other kinds of quantum computer,” he says.

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The milk revolution: A single genetic mutation first let ancient Europeans drink milk

The milk revolution: A single genetic mutation first let ancient Europeans drink milk | Amazing Science |

When a single genetic mutation first let ancient Europeans drink milk, it set the stage for a continental upheaval. During the most recent ice age, milk was essentially a toxin to adults because — unlike children — they could not produce the lactase enzyme required to break down lactose, the main sugar in milk. But as farming started to replace hunting and gathering in the Middle East around 11,000 years ago, cattle herders learned how to reduce lactose in dairy products to tolerable levels by fermenting milk to make cheese or yogurt. Several thousand years later, a genetic mutation spread through Europe that gave people the ability to produce lactase — and drink milk — throughout their lives.

Young children almost universally produce lactase and can digest the lactose in their mother's milk. But as they mature, most switch off the lactase gene. Only 35% of the human population can digest lactose beyond the age of about seven or eight (2). “If you're lactose intolerant and you drink half a pint of milk, you're going to be really ill.

Most people who retain the ability to digest milk can trace their ancestry to Europe, where the trait seems to be linked to a single nucleotide in which the DNA base cytosine changed to thymine in a genomic region not far from the lactase gene. There are other pockets of lactase persistence in West Africa (see Nature 444994996; 2006), the Middle East and south Asia that seem to be linked to separate mutations3 (so called 'Lactase hotspots').

The single-nucleotide switch in Europe happened relatively recently. Thomas and his colleagues estimated the timing by looking at genetic variations in modern populations and running computer simulations of how the related genetic mutation might have spread through ancient populations4. They proposed that the trait of lactase persistence, dubbed the LP allele, emerged about 7,500 years ago in the broad, fertile plains of Hungary.

AckerbauHalle's curator insight, February 13, 2014 1:55 AM

Woher kommt die Fähigkeit zur Verdauung von Laktase? Neue genetische Studien bringen hier Licht ins Dunkel.

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Permian extinction happened within 60,000 years—much faster than previously thought

Permian extinction happened within 60,000 years—much faster than previously thought | Amazing Science |

The largest mass extinction in the history of animal life occurred some 252 million years ago, wiping out more than 96 percent of marine species and 70 percent of life on land—including the largest insects known to have inhabited the Earth. Multiple theories have aimed to explain the cause of what's now known as the end-Permian extinction, including an asteroid impact, massive volcanic eruptions, or a cataclysmic cascade of environmental events. But pinpointing the cause of the extinction requires better measurements of how long the extinction period lasted.

Now researchers at MIT have determined that the end-Permian extinction occurred over 60,000 years, give or take 48,000 years—practically instantaneous, from a geologic perspective. The new timescale is based on more precise dating techniques, and indicates that the most severe extinction in history may have happened more than 10 times faster than scientists had previously thought.

"We've got the extinction nailed in absolute time and duration," says Sam Bowring, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. "How do you kill 96 percent of everything that lived in the oceans in tens of thousands of years? It could be that an exceptional extinction requires an exceptional explanation."

In addition to establishing the extinction's duration, Bowring, graduate student Seth Burgess, and a colleague from the Nanjing Institute of Geology and Paleontology also found that, 10,000 years before the die-off, the oceans experienced a pulse of light carbon, which likely reflects a massive addition of carbon dioxide to the atmosphere. This dramatic change may have led to widespread ocean acidification and increased sea temperatures by 10 degrees Celsius or more, killing the majority of sea life.

But what originally triggered the spike in carbon dioxide? The leading theory among geologists and paleontologists has to do with widespread, long-lasting volcanic eruptions from the Siberian Traps, a region of Russia whose steplike hills are a result of repeated eruptions of magma. To determine whether eruptions from the Siberian Traps triggered a massive increase in oceanic carbon dioxide, Burgess and Bowring are using similar dating techniques to establish a timescale for the Permian period's volcanic eruptions that are estimated to have covered over five million cubic kilometers.

The new timeline adds weight to the theory that the extinction was triggered by massive volcanic eruptions from the Siberian Traps that released volatile chemicals, including carbon dioxide, into the atmosphere and oceans. With such a short extinction timeline, Bowring says it is possible that a single, catastrophic pulse of magmatic activity triggered an almost instantaneous collapse of all global ecosystems.

To confirm whether the Siberian Traps are indeed the extinction's smoking gun, Burgess and Bowring plan to determine an equally precise timeline for the Siberian Traps eruptions, and will compare it to the new extinction timeline to see where the two events overlap. The researchers will investigate additional areas in China to see if the duration of the extinction can be even more precisely determined.

ALFREDO ARIZMENDI's curator insight, February 11, 2015 4:07 AM

En un parpadeo geológico casi toda la vida sobre la faz de la Tierra puede verse barrida. Y mucho espacio adaptativo para los seres que permanecen queda abierto. La evolucion y el tiempo llenan estos espacios de nueva vida, hasta la siguiente extincion. Una rueda inexorable

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Germany: Former war bunker transformed into green energy power plant

Germany: Former war bunker transformed into green energy power plant | Amazing Science |

Energy and utilities company Hamburg Energie has joined forces with IBA Hamburg to transform a former Nazi anti-aircraft flak bunker into a green energy power plant. The Hamburg-based "Energy Bunker" has already begun producing energy for the local community, but once running at full capacity will provide up to 3,000 homes with heating, and another 1,000 homes with electricity.

Originally constructed in 1943 to serve as an anti-aircraft bunker, complete with gun turrets, the 42 m (137 ft) -high building also sheltered local people from Allied bombing raids during WWII. Though the British Army made an attempt to demolish the building on the war's close, blowing up its massively thick walls was deemed too dangerous to nearby buildings. The British ultimately settled on destroying much of the interior, and the bunker remained in this neglected state for over 60 years.

The Energy Bunker is outfitted with several sustainable technologies. The main feature is a 2 million liter (528,000 US gallon) water reservoir that acts as a large heat store and plugs into the existing Reiherstieg district heating network. The reservoir itself is heated by several methods: a biomass power plant and wood chip burning unit which feed into a large boiler, a solar thermal array installed on the roof of the bunker, and waste heat produced by a nearby industrial plant.

A large photovoltaic system is installed on the south-facing facade of the building to produce electricity, and the wood chip burning unit is also used to produce electricity. A peak-load boiler and large battery array ensure that the energy output is kept steady at all times.

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Clever technology decodes more information from single photons

Clever technology decodes more information from single photons | Amazing Science |

It's not quite Star Trek communications—yet. But long-distance communications in space may be easier now that researchers at the National Institute of Standards and Technology (NIST) and Jet Propulsion Laboratory (JPL) have designed a clever detector array that can extract more information than usual from single particles of light.

Described in a new paper, the NIST/JPL array-on-a-chip easily identifies the position of the exact detector in a multi-detector system that absorbs an incoming infrared light particle, or photon. That's the norm for digital photography cameras, of course, but a significant improvement in these astonishingly sensitive detectors that can register a single photon. The new device also records the signal timing, as these particular single-photon detectors have always done.

The technology could be useful in optical communications in space. Lasers can transmit only very low light levels across vast distances, so signals need to contain as much information as possible.

One solution is "pulse position modulation" in which a photon is transmitted at different times and positions to encode more than the usual one bit of information. If a light source transmitted photons slightly to the left/right and up/down, for instance, then the new NIST/JPL detector array circuit could decipher the two bits of information encoded in the spatial position of the photon. Additional bits of information could be encoded by using the arrival time of the photon.

The same NIST/JPL collaboration recently produced detector arrays for the first demonstration of two-way laser communications outside Earth's orbit using the timing version of pulse position modulation. The new NIST/JPL paper shows how to make an even larger array of detectors for future communications systems.

The new technology uses superconducting nanowire single-photon detectors. The current design can count tens of millions of photons per second but the researchers say it could be scaled up to a system capable of counting of nearly a billion photons per second with low dark (false) counts. The key innovation enabling the latest device was NIST's 2011 introduction of a new detector material, tungsten-silicide, which boosted efficiency, the ability to generate an electrical signal for each arriving photon. Detector efficiency now exceeds 90 percent. Other materials are less efficient and would be more difficult to incorporate into complex circuits.

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