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Can Winograd Schemas Replace Turing Test for Defining Human-Level AI?

Can Winograd Schemas Replace Turing Test for Defining Human-Level AI? | Amazing Science | Scoop.it

Earlier this year, a chatbot called Eugene Goostman "beat" a Turing Test for artificial intelligence as part of a contest organized by a U.K. university. Almost immediately, it became obvious that rather than proving that a piece of software had achieved human-level intelligence, all that this particular competition had shown was that a piece of software had gotten fairly adept at fooling humans into thinking that they were talking to another human, which is very different from a measure of the ability to "think." In fact, some observers didn't think the bot was very clever at all.


Clearly, a better test is needed, and we may have one, in the form of a type of question called a Winograd schema that's easy for a human to answer, but a serious challenge for a computer.


The problem with the Turing Test is that it's not really a test of whether an artificial intelligence program is capable of thinking: it's a test of whether an AI program can fool a human. And humans are really, really dumb. We fall for all kinds of tricks that a well-programmed AI can use to convince us that we're talking to a real person who can think.


For example, the Eugene Goostman chatbot pretends to be a 13-year-old boy, because 13-year-old boys are often erratic idiots (I've been one), and that will excuse many circumstances in which the AI simply fails. So really, the chat bot is not intelligent at all—it's just really good at making you overlook the times when it's stupid, while emphasizing the periodic interactions when its algorithm knows how to answer the questions that you ask it.


Conceptually, the Turing Test is still valid, but we need a better practical process for testing artificial intelligence. A new AI contest, sponsored by Nuance Communications and CommonsenseReasoning.org, is offering a US $25,000 prize to an AI that can successfully answer what are called Winograd schemas, named after Terry Winograd, a professor of computer science at Stanford University.


Via Jocelyn Stoller
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20,000+ FREE Online Science and Technology Lectures from Top Universities

20,000+ FREE Online Science and Technology Lectures from Top Universities | Amazing Science | Scoop.it

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Physicists find a new way to push electrons around

Physicists find a new way to push electrons around | Amazing Science | Scoop.it
Discovery might ultimately lead to new, more energy-efficient transistors and microchips.


When moving through a conductive material in an electric field, electrons tend to follow the path of least resistance — which runs in the direction of that field.


But now physicists at MIT and the University of Manchester have found an unexpectedly different behavior under very specialized conditions — one that might lead to new types of transistors and electronic circuits that could prove highly energy-efficient.


They’ve found that when a sheet of graphene — a two-dimensional array of pure carbon — is placed atop another two-dimensional material, electrons instead move sideways, perpendicular to the electric field. This happens even without the influence of a magnetic field — the only other known way of inducing such a sideways flow.


What’s more, two separate streams of electrons would flow in opposite directions, both crosswise to the field, canceling out each other’s electrical charge to produce a “neutral, chargeless current,” explains Leonid Levitov, an MIT professor of physics and a senior author of a paper describing these findings this week in the journal Science.

The exact angle of this current relative to the electric field can be precisely controlled, Levitov says. He compares it to a sailboat sailing perpendicular to the wind, its angle of motion controlled by adjusting the position of the sail.


Levitov and co-author Andre Geim at Manchester say this flow could be altered by applying a minute voltage on the gate, allowing the material to function as a transistor. Currents in these materials, being neutral, might not waste much of their energy as heat, as occurs in conventional semiconductors — potentially making the new materials a more efficient basis for computer chips.


“It is widely believed that new, unconventional approaches to information processing are key for the future of hardware,” Levitov says. “This belief has been the driving force behind a number of important recent developments, in particular spintronics” — in which the spin of electrons, not their electric charge, carries information.

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Japanese woman is first recipient of next-generation stem cells

Japanese woman is first recipient of next-generation stem cells | Amazing Science | Scoop.it

A Japanese woman in her 70s is the world's first recipient of cells derived from induced pluripotent stem cells, a technology that has created great expectations since it could offer the same advantages as embryo-derived cells but without some of the controversial aspects and safety concerns.


In a two-hour procedure, a team of three eye specialists lead by Yasuo Kurimoto of the Kobe City Medical Center General Hospital, transplanted a 1.3 by 3.0 millimeter sheet of retinal pigment epithelium cells into an eye of the Hyogo prefecture resident, who suffers from age-related macular degeneration.


The procedure took place at the Institute of Biomedical Research and Innovation Hospital, next to the RIKEN Center for Developmental Biology (CDB) where ophthalmologist Masayo Takahashi had developed and tested the epithelium sheets. She derived them from the patient's skin cells, after producing induced pluripotent stem (iPS) cells and then getting them to differentiate into retinal cells. Afterwards, the patient experienced no effusive bleeding or other serious problems, RIKEN has reported.


The patient “took on all the risk that go with the treatment as well as the surgery”, Kurimoto said in a statement released by RIKEN. “I have deep respect for bravery she showed in resolving to go through with it.”

He hit a somber note in thanking Yoshiki Sasai, a CDB researcher who recenty committed suicide. “This project could not have existed without the late Yoshiki Sasai’s research, which led the way to differentiating retinal tissue from stem cells.”


Kurimoto also thanked Shinya Yamanaka, a stem-cell scientist at Kyoto University “without whose discovery of iPS cells, this clinical research would not be possible.” Yamanaka shared the 2012 Nobel Prize in Physiology or Medicine for that work.


Kurimoto performed the procedure a mere four days after a health-ministry committee gave Takahashi clearance for the human trials (see 'Next-generation stem cells cleared for human trial').


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Shattering DNA may have let gibbons evolve into new species

Shattering DNA may have let gibbons evolve into new species | Amazing Science | Scoop.it

Gibbons have such strange, scrambled DNA, it looks like someone has taken a hammer to it. Their genome has been massively reshuffled, and some biologists say that could be how new gibbon species evolved.

Gibbons are apes, and were the first to break away from the line that led to humans. There are around 16 living gibbon species, in four genera. They all have small bodies, long arms and no tails. But it's what gibbons don't share that is most unusual. Each species carries a distinct number of chromosomes in its genome: some species have just 38 pairs, some as many as 52 pairs.


"This 'genome plasticity' has always been a mystery," says Wesley Warrenof Washington University in St Louis, Missouri. It is almost as if the genome exploded and was then pieced back together in the wrong order. To understand why, Warren and his colleagues have now produced the first draft of a gibbon genome. It comes from a female northern white-cheeked gibbon (Nomascus leucogenys) called Asia.

Inside the genome, Warren and his colleagues may have identified one of the players responsible for the reshuffling. It is called LAVA, and it is a piece of DNA called a retrotransposon that inserts itself into the genetic code. Seemingly unique to gibbons, LAVA tends to slip into genes that help control the way chromosomes pair up during cell division. By altering how those genes work, LAVA has made the gibbon genome unstable.

We believe this is the driving force that causes, for want of a better word, the 'scrambling' of the genome," says Warren. However, solving this mystery has created another. Such dramatic genome changes are normally associated with diseases such as cancer, and should be harmful. "It's a complete mystery still how these genomes are able to pass from one generation to the next and not cause any major issues in terms of survival of the species," says Warren. It may be that genomes are much more resilient than anyone expected, saysJames Shapiro at the University of Chicago. "The genome can endure lots of changes and still function."

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Fastest Ever Built Photon Switch of 500 GHz in an Engineered Fiber

Fastest Ever Built Photon Switch of 500 GHz in an Engineered Fiber | Amazing Science | Scoop.it

Researchers at the University of California, San Diego have built the first 500 Gigahertz (GHz) photon switch. “Our switch is more than an order of magnitude faster than any previously published result to date,” said UC San Diego electrical and computer engineering professor Stojan Radic. “That exceeds the speed of the fastest lightwave information channels in use today.” The work took nearly four years to complete and it opens a fundamentally new direction in photonics – with far-reaching potential consequences for the control of photons in optical fiber channels.


According to an article in the journal Science*, switching photons at such high speeds was made possible by advances in the control of a strong optical beam using only a few photons, and by the scientists’ ability to engineer the optical fiber itself with accuracy down to the molecular level.


In the research paper, Radic and his colleagues in the UC San Diego Jacobs School of Engineering argue that ultrafast optical control is critical to applications that must manipulate light beyond the conventional electronic limits. In addition to very fast beam control and fast switching, the latest work opens the way to a new class of sensitive receivers (also capable of operating at very high rates), faster photon sensors, and optical processing devices.


To build the new switch, the UC San Diego team developed a new measurement technique capable of resolving sub-nanometer fluctuations in the fiber core. This was critical because local fiber dispersion varies substantially, even with small core fluctuations, and until recently, control of such small variations was not considered feasible, particularly over long device lengths.


In the experiment, a three-photon input was used to manipulate a Watt-scale beam at a speed exceeding 500 Gigahertz.

In their research, the engineers in the Photonic Systems Laboratory of UC San Diego’s Qualcomm Institute demonstrated that fast control becomes possible in fiber made of silica glass. “Silica fiber represents a nearly ideal physical platform because of very low optical loss, exceptional transparency and kilometer-scale interaction lengths,” noted Radic. “We showed that a silica fiber core can be controlled with sub-nanometer precision and be used for fast, few-photon control.”


Until recently, control of small variations was not considered feasible – particularly over long scales. But once they were able to profile the fluctuation of the actual fiber, it became clear that the silica fiber core could be controlled with sub-nanometer precision – and be used for fast, few-photon control.


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Woman of 24 found to have no cerebellum in her brain

Woman of 24 found to have no cerebellum in her brain | Amazing Science | Scoop.it

A 24-year-old woman has discovered that her cerebellum is completely missing, explaining some of the unusual problems she has had with movement and speech. The case highlights just how adaptable the organ is.


The discovery was made when the woman was admitted to the Chinese PLA General Hospital of Jinan Military Area Command in Shandong Province complaining of dizziness and nausea. She told doctors she'd had problems walking steadily for most of her life, and her mother reported that she hadn't walked until she was 7 and that her speech only became intelligible at the age of 6.

Doctors did a CAT scan and immediately identified the source of the problem – her entire cerebellum was missing (see scan, below left). The space where it should be was empty of tissue. Instead it was filled with cerebrospinal fluid, which cushions the brain and provides defence against disease.


The cerebellum – sometimes known as the "little brain" – is located underneath the two hemispheres. It looks different from the rest of the brain because it consists of much smaller and more compact folds of tissue. It represents about 10 per cent of the brain's total volume but contains 50 per cent of its neurons.


Although it is not unheard of to have part of your brain missing, either congenitally or from surgery, the woman joins an elite club of just nine people who are known to have lived without their entire cerebellum. A detailed description of how the disorder affects a living adult is almost non-existent, say doctors from the Chinese hospital, because most people with the condition die at a young age and the problem is only discovered on autopsy (Brain,doi.org/vh7).


The cerebellum's main job is to control voluntary movements and balance, and it is also thought to be involved in our ability to learn specific motor actions and speak. Problems in the cerebellum can lead to severe mental impairment, movement disorders, epilepsy or a potentially fatal build-up of fluid in the brain. However, in this woman, the missing cerebellum resulted in only mild to moderate motor deficiency, and mild speech problems such as slightly slurred pronunciation. Her doctors describe these effects as "less than would be expected", and say her case highlights the remarkable plasticity of the brain.

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New set of 4 factors (Sall4, Nanog, Esrrb, and Lin28) for reprogramming mice iPSCs generates higher quality cells

New set of 4 factors (Sall4, Nanog, Esrrb, and Lin28) for reprogramming mice iPSCs generates higher quality cells | Amazing Science | Scoop.it

Induced pluripotent stem cells (iPSCs) are commonly generated by transduction of Oct4, Sox2, Klf4, and Myc (OSKM) into cells. Although iPSCs are pluripotent, they frequently exhibit high variation in terms of quality, as measured in mice by chimera contribution and tetraploid complementation. Reliably high-quality iPSCs will be needed for future therapeutic applications. Here, we show that one major determinant of iPSC quality is the combination of reprogramming factors used.


Based on tetraploid complementation, we found that ectopic expression of Sall4, Nanog, Esrrb, and Lin28 (SNEL) in mouse embryonic fibroblasts (MEFs) generated high-quality iPSCs more efficiently than other combinations of factors including OSKM. Although differentially methylated regions, transcript number of master regulators, establishment of specific superenhancers, and global aneuploidy were comparable between high- and low-quality lines, aberrant gene expression, trisomy of chromosome 8, and abnormal H2A.X deposition were distinguishing features that could potentially also be applicable to human.

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Malaria parasites found to hide out in the bone marrow

Malaria parasites found to hide out in the bone marrow | Amazing Science | Scoop.it

Malaria is an infectious disease which claims the lives of more children worldwide than any other; it is caused by parasitic micro-organisms, plasmodiums. These parasites are transmitted to their hosts via mosquito bites, where they induce a range of symptoms, including vomiting, fever, headaches, and, in severe cases, death. Incidence of malaria is prevalent in poverty stricken areas around the equator, with an estimated 207 million cases in 2012.  The most life threatening form of the disease is caused by Plasmodium falciparum


Within humans, P. falciparum undergoes two distinct stages, asexual replication, and differentiation into what are called gametocytes. Asexual replication occurs within red blood cells, with pathological symptoms arising from the inevitable red blood cell rupturing. Released parasites generally invade additional red blood cells for subsequent rounds of asexual replication; however, a small subset of parasites instead differentiate into the male and female forms that are refered to as gametocytes. Once taken up by a female Anopheles mosquito, these gametocytes are able to undergo sexual replication. Thus, the differentiation of P. falciparum into gametocytes represents an attractive target for intervention strategies. However, within the blood only mature gametocytes are found, and until recently, relatively little was known about immature gametocyte sequestration within tissues.


recent study carried out a systematic organ survey of children who died from malaria, successfully identifying sites of immature gametocyte accumulation using a combination of immunohistochemical labelling, and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The study provides strong evidence that gametocyte development occurs within the haematopoietic system present in the bone marrow, where they may form and develop within red blood cell precursors. Furthermore, binding interactions with red blood cell precursors seem to support the retention of developing gametocytes within the bone marrow’s extravascular space, where they are able to avoid immune detection until they are mature enough to be released back into the blood. The observation of gametocytes adopting a specialised niche within the haematopoietic system of the bone marrow is supported by anindependent study, which earlier this year used qRT-PCR to demonstrate that the bone marrow of infected children is enriched for immature gametocytes.


The recently characterised locations and mechanisms of gametocyte sequestration within the bone marrow, provide novel targets through which malaria transmission could be blocked, advancing both prevention and treatment efforts.

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Estimating the fatality of the 2014 West African Ebola Outbreak

Estimating the fatality of the 2014 West African Ebola Outbreak | Amazing Science | Scoop.it

Case fatality rate" - or CFR - is a term that's been tossed around a lot lately in the context of the 2014 West African Ebola outbreak… But what does it really mean?


The CFR – which is calculated by dividing the number of deaths that have occurred due to a certain condition by the total number of cases – is actually a measure of risk. For infectious disease, CFR is a very important epidemiological measure to estimate because it tells us the probability of dying after infection. If estimated properly in the middle of an outbreak, it can even help us examine the efficacy of interventions as they take place.


Because different outbreaks of the same disease can demonstrate different CFRs, there’s usually a range of possible CFRs for a given disease. In the past, outbreaks caused by Zaire ebolavirus have demonstrated a mean end-of-outbreak CFR of 80% . But based off of the WHO's most recent report, it seems that only about 53% of reported Ebola cases thus far have ended in death since the 2014 outbreak began.


However, if we want to be particular, that 53% isn't really a CFR; it's actually the proportion of fatal cases - or PFC. This is a critical distinction. Because the outbreak in West Africa is still ongoing, we can't calculate end-of-outbreak CFR yet. We don’t know how many people will die from Ebola in the weeks ahead or how many total cases will ultimately accumulate by the end of the outbreak. So, for the time being, we have to make do with the PFC, which is essentially the number of deaths thus far divided by the number of cases to date.


When the WHO releases a report on the current situation in West Africa, it tells us two things: the number of people who've died and the number of reported cases at some specified point in time. For instance, in the most recent report, the WHO cited 4293 total cases and 2296 deaths as of September 8th. Dividing 2296 by 4293 gives us our previously stated PFC of 53%.


At first glance, it might seem then that only 53% of Ebola cases have been dying during this outbreak - a good deal less than the 80% we've seen prior... But what it really means is that only 53% of Ebola cases have died as of September 8th. We have no way of knowing whether all the people who were still hospitalized as of September 8th will survive the disease. Because of this, mid-outbreak PFC - as we've defined it thus far - doesn't tell us much about the likelihood of dying.


Despite Ebola’s frightening reputation, not all Ebola fatalities happen quickly. Without a little fine-tuning, PFC doesn't account for the lag between when a case is reported and when a case dies - approximately 16 days for this outbreak [3]. What this means is that the 2296 deaths reported as of September 8th were all likely reported as cases by August 23rd. Adjusting PFC for this lag-time gives us a much better approximation of CFR well before the outbreak ends.


Below is a chart that shows both unadjusted and lag-adjusted PFC over time for Ebola in West Africa [5]. The lag-adjusted PFC - about 80-85% - is significantly higher than the unadjusted PFC but is consistent with recent fatality estimates by Médecins Sans Frontières.

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Digital mapping uncovers ‘super henge’ that dwarfed Stonehenge

Digital mapping uncovers ‘super henge’ that dwarfed Stonehenge | Amazing Science | Scoop.it

Every summer solstice, tens of thousands of people throng to Stonehenge, creating a festival-like atmosphere at the 4,400-year-old stone monument. For the 2015 solstice, they will have a bit more room to spread out. A just-completed four-year project to map the vicinity of Stonehenge reveals a sprawling complex that includes 17 newly discovered monuments and signs of 1.5 kilometre-round “super henge”.


The digital map — made from high-resolution radar and magnetic and laser scans that accumulated several terabytes of data — shatters the picture of Stonehenge as a desolate and exclusive site that was visited by few, says Vincent Gaffney, an archaeologist at the University of Birmingham, UK, who co-led the effort.


Take the cursus, a 3-kilometer-long, 100-meter-wide ditch north of Stonehenge that was thought to act as barrier. The team’s mapping uncovered gaps in the cursus leading to Stonehenge, as well as several large pits, one of which would have been perfectly aligned with the setting solstice Sun. New magnetic and radar surveys of the Durrington Walls (which had been excavated before) uncovered more than 60 now-buried holes in which stones would have sat, and a few stones still buried.


“They look as they may have been pushed over. That’s a big prehistoric monument which we never knew anything about,” says Gaffney, who calls the structure a ‘super henge.’ His team will discuss the work at the British Science Festival this week, and they plan to present it to the institutions that manage the site. “I’m sure it will guide future excavations,” Gaffney says.

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Novel forms of superconductivity: Two-dimensional electron liquids

Novel forms of superconductivity: Two-dimensional electron liquids | Amazing Science | Scoop.it

Truly two-dimensional objects are rare. Even a thin piece of paper is trillions of atoms thick. When physicists do succeed in producing 2D systems, quantum interactions can lead to new phenomena and Nobel prizes. Two examples: graphene—-single-atom-thick sheets of carbon atoms—-has unique mechanical, electrical, and optical properties; and two-dimensional electron gases (2DEG)—-planar collections of electrons supported at the interface between certain semiconductors such as gallium arsenide—-allow the observation of such emergent behaviors as the quantum Hall effect and the spin Hall effect.


A relatively new frontier for studying 2D matter is provided by planar collections of electrons at the surface of transition-metal-oxide (TMO) materials, in which high electron densities give rise to interactions that are stronger than in semiconductors. Consequently it is more accurate to refer to the TMO electron ensemble as a 2D liquid rather than as a 2D gas. Scientists hope to find exotic emergent phenomena in these high-density, highly-interactive electron environments.


One of the leaders in this effort is James Williams, a new fellow at the Joint Quantum Institute (JQI), where he is also an assistant professor of physics at the University of Maryland. Before he left Stanford University, Williams and his colleagues performed tests on a thin sample of strontium titanate (STO) covered over with an electrolyte gel, a material in which negative and positive ions dissociate (saltwater is a common electrolyte: Na+ and Cl- ions come apart in a water solution). Their results appear in the journal Nature Physics.


Their new experimental results are reported online in the journal Nature Physics on August 31, 2014. The authors speculate that this behavior is consistent with (but not yet proof of) of novel superconductivity, one candidate of which is a p-wave superconductor . More research needs to be done before this speculation is given a strong footing. In conventional, or s-wave superconductivity, the pairs of electrons (Cooper pairs) that constitute a zero-resistance current, are spherical in shape. In p-wave superconductivity, the pairs would look more like miniature dumbbells festooned with additional lobes.


P-wave superconductivity has not been unambiguously seen yet since the anatomy of the electron pairs is difficult to establish. But the search has generated much interest. This is because theorists believe the p-wave materials could support the existence of Majorana particles (named for physicist Ettore Majorana), which are expected to have strange properties, such as being their own antiparticles.

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Rethinking basic science of graphene synthesis shows route to industrial-scale production

Rethinking basic science of graphene synthesis shows route to industrial-scale production | Amazing Science | Scoop.it

A new route to making graphene has been discovered that could make the 21st century's wonder material easier to ramp up to industrial scale. Graphene—a tightly bound single layer of carbon atoms with super strength and the ability to conduct heat and electricity better than any other known material—has potential industrial uses that include flexible electronic displays, high-speed computing, stronger wind-turbine blades, and more-efficient solar cells, to name just a few under development.

In the decade since Nobel laureates Konstantin Novoselov and Andre Geim proved the remarkable electronic and mechanical properties of graphene, researchers have been hard at work to develop methods of producing pristine samples of the material on a scale with industrial potential. Now, a team of Penn State scientists has discovered a route to making single-layer graphene that has been overlooked for more than 150 years.


"There are lots of layered materials similar to graphene with interesting properties, but until now we didn't know how to chemically pull the solids apart to make single sheets without damaging the layers," said Thomas E. Mallouk, Evan Pugh Professor of Chemistry, Physics, and Biochemistry and Molecular Biology at Penn State. In a paper first published online on Sept. 9 in the journal Nature Chemistry, Mallouk and colleagues at Penn State and the Research Center for Exotic Nanocarbons at Shinshu University, Japan, describe a method called intercalation, in which guest molecules or ions are inserted between the carbon layers of graphite to pull the single sheets apart.


The intercalation of graphite was achieved in 1841, but always with a strong oxidizing or reducing agent that damaged the desirable properties of the material. One of the most widely used methods to intercalate graphite by oxidation was developed in 1999 by Nina Kovtyukhova, a research associate in Mallouk's lab.

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Flies live 30 percent longer when AMPK is activated

Flies live 30 percent longer when AMPK is activated | Amazing Science | Scoop.it

Activating a specific gene in the intestines of a fruit fly made it live 30 percent longer, a team of biologists has reported.


The gene in question, AMPK, detects and reacts to fluctuations in the body to help modulate energy levels. The gene is also found in humans in low levels, leading the UCLA team to postulate in the open source journal Cell Reports that we could use it to learn about potentially delaying the ageing process.


Key to this statement is the fact that in the experiment on the Drosophila melanogaster fruit fly, the ageing process slowed throughout the insect's organs -- not just in the intestine where AMPK was activated.


The team behind the study is taking an approach similar to that ofbiogerontologist and SENS Foundation co-founder Aubrey de Grey, who argues that instead of attempting to modify our cells to combat disease, we must repair the molecular damage that happens as cells degrade. Among the cell death, cell divisions and mitochondria mutations that he cites as being cellular problems to combat, is "molecular garbage", a problem also flagged up by the UCLA team. In the body, we naturally discard of this molecular garbage through a process known as autophagy.


Autophagy allows any cells that are old or degrading to be shed, and AMPK is known to help activate that system. "However, the tissue-specific mechanisms involved are poorly understood," writes the UCLA team in Cell Reports. If we could better understand and harness its capabilities, they argue, we could go some way in slowing the aging process by tackling the molecular garbage problem prevalent in old age. It is molecular garbage and protein buildups that contribute to some of the biggest killer diseases in later years.

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New math explains dynamics of fluid systems that mimic many peculiarities of quantum mechanics

New math explains dynamics of fluid systems that mimic many peculiarities of quantum mechanics | Amazing Science | Scoop.it

In the early days of quantum physics, in an attempt to explain the wavelike behavior of quantum particles, the French physicist Louis de Broglie proposed what he called a “pilot wave” theory. According to de Broglie, moving particles — such as electrons, or the photons in a beam of light — are borne along on waves of some type, like driftwood on a tide.


Physicists’ inability to detect de Broglie’s posited waves led them, for the most part, to abandon pilot-wave theory. Recently, however, a real pilot-wave system has been discovered, in which a drop of fluid bounces across a vibrating fluid bath, propelled by waves produced by its own collisions.


In 2006, Yves Couder and Emmanuel Fort, physicists at Université Paris Diderot, used this system to reproduce one of the most famous experiments in quantum physics: the so-called “double-slit” experiment, in which particles are fired at a screen through a barrier with two holes in it.


In the latest issue of the journal Physical Review E (PRE), a team of MIT researchers, in collaboration with Couder and his colleagues, report that they have produced the fluidic analogue of another classic quantum experiment, in which electrons are confined to a circular “corral” by a ring of ions. In the new experiments, bouncing drops of fluid mimicked the electrons’ statistical behavior with remarkable accuracy.


“This hydrodynamic system is subtle, and extraordinarily rich in terms of mathematical modeling,” says John Bush, a professor of applied mathematics at MIT and corresponding author on the new paper. “It’s the first pilot-wave system discovered and gives insight into how rational quantum dynamics might work, were such a thing to exist.”


John Bush, a professor of applied mathematics at MIT, believes that pilot-wave theory deserves a second look. That’s because Yves Couder, Emmanuel Fort, and colleagues at the University of Paris Diderot have recently discovered a macroscopic pilot-wave system whose statistical behavior, in certain circumstances, recalls that of quantum systems.


Couder and Fort’s system consists of a bath of fluid vibrating at a rate just below the threshold at which waves would start to form on its surface. A droplet of the same fluid is released above the bath; where it strikes the surface, it causes waves to radiate outward. The droplet then begins moving across the bath, propelled by the very waves it creates.


“This system is undoubtedly quantitatively different from quantum mechanics,” Bush says. “It’s also qualitatively different: There are some features of quantum mechanics that we can’t capture, some features of this system that we know aren’t present in quantum mechanics. But are they philosophically distinct?”

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Next-Gen Glaucoma Treatments: Microfluidic Implant And Smart Phone App Monitoring

Next-Gen Glaucoma Treatments: Microfluidic Implant And Smart Phone App Monitoring | Amazing Science | Scoop.it

Stanford Professor of Bioengineering and Applied Physics, Stephen Quake, and Head of the Ophthalmic Science and Engineering Lab at Bar Ilan University Dr. Yossi Mandell teamed up to create a state-of-the-art intraocular implant that will change glaucoma treatment by making intraocular pressure readings frequent, easy and convenient.


Made to fit inside a commonly used intraocular lens prosthetic, and implanted through simple surgery such as for cataracts which many glaucoma patients already receive, the device measures the pressure of the fluid within the eye.  A smart phone app or a wearable device such as Google Glass allows the wearer to take “snapshots” of the device that reports back the pressure.


The lens device holds a tiny tube, capped at one end and opened on the other, filled with gas. As the fluid pressure pushes against the gas, a marked scale permits reading of the intraocular pressure.  The implant does not interfere with vision, as proven in an Air Force-approved vision test, and in one reported study the implant was responsible for changes to treatment for glaucoma in nearly 80 percent of the wearers.


Nearly 2.2 million Americans battle the eye disease glaucoma.  Patients endure weekly visits to the ophthalmologist to have the disease monitored and treated. The disease is characterized by increasing pressure inside the eye, which results in a continuous loss of a specific type of retinal cell accompanied by degradation of the optic nerve fiber.  The mechanism that links pressure to damage is not clear but there is correlation between the intensity of pressure readings and level of damage.

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Future of Oceanography: Crowdsourcing the Collection of Oceanographic Data

Future of Oceanography: Crowdsourcing the Collection of Oceanographic Data | Amazing Science | Scoop.it

We live on a vast, underexplored planet that is largely ocean. Despite modern technology, Global Positioning System (GPS) navigation, and advanced engineering of ocean vessels, the ocean is unforgiving, especially in rough weather. Coastal ocean navigation, with risks of running aground and inconsistent weather and sea patterns, can also be challenging and hazardous. In 2012, more than 100 international incidents of ships sinking, foundering, grounding, or being lost at sea were reported (http://en.wikipedia.org/wiki/List_of_shipwrecks_in_2012). Even a modern jetliner can disappear in the ocean with little or no trace[1], and the current costs and uncertainty associated with search and rescue make the prospects of finding an object in the middle of the ocean daunting [2].


Notwithstanding satellite constellations, autonomous vehicles, and more than 300 research vessels worldwide (www.wikipedia.org/wiki/List_of_research_vessels_by_country), we lack fundamental data relating to our oceans. These missing data hamper our ability to make basic predictions about ocean weather, narrow the trajectories of floating objects, or estimate the impact of ocean acidification and other physical, biological, and chemical characteristics of the world's oceans. To cope with this problem, scientists make probabilistic inferences by synthesizing models with incomplete data. Probabilistic modeling works well for certain questions of interest to the scientific community, but it is difficult to extract unambiguous policy recommendations from this approach. The models can answer important questions about trends and tendencies among large numbers of events but often cannot offer much insight into specific events. For example, probabilistic models can tell us with some precision the extent to which storm activity will be intensified by global climate change but cannot yet attribute the severity of a particular storm to climate change. Probabilistic modeling can provide important insights into the global traffic patterns of floating debris but is not of much help to search-and-rescue personnel struggling to learn the likely trajectory of a particular piece of debris left by a wreck.


Oceanographic data are incomplete because it is financially and logistically impractical to sample everywhere. Scientists typically sample over time, floating with the currents and observing their temporal evolution (the Langrangian approach), or they sample across space to cover a gradient of conditions—such as temperature or nutrients (the Eulerian approach). These observational paradigms have various strengths and weaknesses, but their fundamental weakness is cost. A modern ocean research vessel typically costs more than US$30,000 per day to operate—excluding the full cost of scientists, engineers, and the cost of the research itself. Even an aggressive expansion of oceanographic research budgets would not do much to improve the precision of our probabilistic models, let alone to quickly and more accurately locate missing objects in the huge, moving, three-dimensional seascape. Emerging autonomous technologies such as underwater gliders and in situ biological samplers (e.g., environmental sample processors) help fill gaps but are cost prohibitive to scale up. Similarly, drifters (e.g., the highly successful Argo floats program) have proven very useful for better defining currents, but unless retrieved after their operational lifetime, they become floating trash, adding to a growing problem.


Long-term sampling efforts such as the continuous plankton recorder in the North Sea and North Atlantic [3] provide valuable data on decadal trends and leveraged English Channel ferries to accomplish much of the sampling. Modernizing and expanding this approach is a goal of citizen science initiatives.

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Option topic: Marine environmental change and management

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Starting march 2015, the general public will be able to vote names for already discovered exoplanets

Starting march 2015, the general public will be able to vote names for already discovered exoplanets | Amazing Science | Scoop.it

What will be named?

  1. Exoplanets belonging to a list of 305 well-characterised exoplanets, discovered prior to 31 December 2008, and their host stars. The date refers to the date of submission to a refereed journal. Many exoplanets discovered after this date require confirmation or are incompletely characterised.
  2. These exoplanets belong to 260 exoplanetary systems comprising one to five members.
  3. These systems have been selected for naming by the IAU Working Group Exoplanets for the Public, and are published on the www.NameExoWorlds.org website.
  4. This master list will be referred to as the ExoWorlds list and forms the basis of the NameExoWorlds campaign led by the IAU’s Public Naming of Planets and Planetary Satellites Working Group.
  5. The exoplanetary systems in the ExoWorlds list can be named and recognised by the IAU only via the NameExoWorlds campaign.
  6. A vote will be organised among registered organisations (see next Section) to select the top 20-30 most popular exoplanetary systems in the ExoWorlds list for naming.
  7. During the first NameExoWorlds campaign, proposals for names for members of the selected 20-30 ExoWorlds (host stars and their exoplanets) shall be submitted towww.NameExoWorlds.org only by the registered organisations.


Who can submit names?

  1. Only public astronomical organisations (such as Planetariums, Science Centres, Amateur Astronomy Clubs, Online Astronomy platforms) or non-profit astronomy-interested organisations (such as High schools, Cultural clubs) with a proven interest in astronomy, (hereafter "organisations" for short) based in any country, shall be allowed to propose names.
  2. To suggest names, these organisations must first register on the IAU Directory for World Astronomy website providing their website URL, the organisation’s registration number/certificate/document number testifying its status, and the full name, e-mail and postal address of a contact person.
  3. The website of the organisation shall demonstrate its activity or interest in astronomy, and a verifiable non-profit status.


How can names be submitted?

  1. Registered organisations may send only one proposal, concerning only one of the 20-30 ExoWorlds selected, independently of the number of exoplanets belonging to the system of their choice.
  2. These organisations may not gather suggestions for names by means of sales, donations or other financial transactions. Organisations may not sell their right to suggest names to other entities or try to gain any other non-commercial or commercial benefit from their right to suggest names to the IAU.
  3. Organisations shall send their naming proposals to www.NameExoWorlds.org along with a detailed justification of the host star and exoplanet names (of a single ExoWorld) in English (max. 250 words).
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Scientists reset human stem cells to earliest developmental state equivalent to 7-9 days old embryo

Scientists reset human stem cells to earliest developmental state equivalent to 7-9 days old embryo | Amazing Science | Scoop.it

Scientists have successfully ‘reset’ human pluripotent stem cells to the earliest developmental state – equivalent to cells found in an embryo before it implants in the womb (7-9 days old). These ‘pristine’ stem cells may mark the true starting point for human development, but have until now been impossible to replicate in the lab. fThe discovery, published in Cell, will lead to a better understanding of human development and could in future allow the production of safe and more reproducible starting materials for a wide range of applications including cell therapies.

Human pluripotent stem cells, which have the potential to become any of the cells and tissues in the body, can be made in the lab either from cells extracted from a very early stage embryo or from adult cells that have been induced into a pluripotent state.

However, scientists have struggled to generate human pluripotent stem cells that are truly pristine (also known as naïve). Instead, researchers have only been able to derive cells which have advanced slightly further down the developmental pathway. These bear some of the early hallmarks of differentiation into distinct cell types – they’re not a truly ‘blank slate’. This may explain why existing human pluripotent stem cell lines often exhibit a bias towards producing certain tissue types in the laboratory.

Now researchers led by the Wellcome Trust-Medical Research Council (MRC) Cambridge Stem Cell Institute at the University of Cambridge, have managed to induce a ground state by rewiring the genetic circuitry in human embryonic and induced pluripotent stem cells. Their ‘reset cells’ share many of the characteristics of authentic naïve embryonic stem cells isolated from mice, suggesting that they represent the earliest stage of development.

“Capturing embryonic stem cells is like stopping the developmental clock at the precise moment before they begin to turn into distinct cells and tissues,” explains Professor Austin Smith, Director of the Stem Cell Institute, who co-authored the paper. “Scientists have perfected a reliable way of doing this with mouse cells, but human cells have proved more difficult to arrest and show subtle differences between the individual cells. It’s as if the developmental clock has not stopped at the same time and some cells are a few minutes ahead of others.”

The process of generating stem cells in the lab is much easier to control in mouse cells, which can be frozen in a state of naïve pluripotency using a protein called LIF. Human cells are not as responsive to LIF, so they must be controlled in a different way that involves switching key genes on and off. For this reason scientists have been unable to generate human pluripotent cells that are as primitive or as consistent as mouse embryonic stem cells.

The researchers overcame this problem by introducing two genes – NANOG and KLF2 – causing the network of genes that control the cell to reboot and induce the naïve pluripotent state. Importantly, the introduced genes only need to be present for a short time. Then, like other stem cells, reset cells can self-renew indefinitely to produce large numbers, are stable and can differentiate into other cell types, including nerve and heart cells.

By studying the reset cells, scientists will be able to learn more about how normal embryo development progresses and also how it can go wrong, leading to miscarriage and developmental disorders. The naïve state of the reset stem cells may also make it easier and more reliable to grow and manipulate them in the laboratory and may allow them to serve as a blank canvas for creating specialised cells and tissues for use in regenerative medicine.

Professor Smith adds: “Our findings suggest that it is possible to rewind the clock to achieve true ground state pluripotency in human cells. These cells may represent the real starting point for formation of tissues in the human embryo. We hope that in time they will allow us to unlock the fundamental biology of early development, which is impossible to study directly in people.” - See more at: http://www.cam.ac.uk/research/news/scientists-reset-human-stem-cells-to-earliest-developmental-state#sthash.4gxh2MI9.dpuf

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Electric Prism Separates Ortho and Para Nuclear Spin States of Water for the First Time

Electric Prism Separates Ortho and Para Nuclear Spin States of Water for the First Time | Amazing Science | Scoop.it

At first glance, water seems to be a simple molecule in which a single oxygen atom is bound to two hydrogen atoms. However, it is more complex when taking into account hydrogen’s nuclear spin – a property reminiscent of a rotation of its nucleus about its own axis. The spin of a single hydrogen can assume two different orientations, symbolized as up and down. Thus, the spins of water’s two hydrogen atoms can either add up, called ortho water, or cancel out, called para water. Ortho and para states are also said to be symmetric and antisymmetric, respectively.


Fundamental symmetry rules prohibit para water from turning into ortho water and vice versa – at least theoretically. “If you had a magic bottle with isolated paraand ortho molecules, they would remain in their spin states at all times,” says DESY scientist Jochen Küpper who led the recent study. “In principle, they are different molecular species, different types of water.” However, in the real world, water molecules are not isolated and frequently collide with other molecules or surfaces in their vicinity, causing nuclear spin orientations to change. “Through these interactions, para and ortho water can actually transform easily into one another,” explains Küpper who is also a professor at the University of Hamburg and a member of the Hamburg Centre for Ultrafast Imaging (CUI). “Therefore, it is very challenging to separate them and produce water that is not a mixture of both.”


Yet, the CFEL researchers have now demonstrated a way of isolating para and ortho water in the lab. To start, the scientists placed a drop of water in a compartment, which they pressurized with neon or argon gas. This mixture was released into vacuum through a pulsed valve. “Due to the large pressure difference, the gas expands quickly into the vacuum when the valve is opened, dragging along water molecules and, at the same time, cooling them down,” says Daniel Horke, the first author of the study.


This expansion produces a narrow beam of ultracold water molecules, which propagate at supersonic speed and are so dilute that individual molecules no longer collide with each other, thereby suppressing the conversion between para and ortho spin states.


The molecular beam then travels through a strong electric field, which deflects the water molecules from their original flight path and acts like a prism for nuclear spin states. “Para andortho water interact with the electric field differently,” Horke explains. “Thus, they also get deflected differently, allowing us to separate them in space and obtain pure para and orthosamples.” Spectroscopy showed that the purity of the para and ortho water was 74 per cent and over 97 per cent, respectively. Especially for para water the purity can be greatly enhanced in the future, as Horke says. Storing the separated water species was not an aim of the study.


The new method could benefit studies of a wide range of phenomena. In astrophysics, for example, it is commonly assumed that the relative amounts of para and ortho species can be linked to the temperature of interstellar ice. This theory is based on the temperature dependence of hydrogen’s ortho-to-para ratio, which is three to one at room temperature and drops with decreasing temperatures. “In fact, certain regions of the universe exhibit ratios that are quite different from what you would expect,” Horke says. “Yet, the specific reasons are unknown and lab-based experiments could provide new insights.”


Back on Earth, the study may also help determine the structures of proteins – biomolecules that are essential to all life. A method known as nuclear magnetic resonance (NMR) spectroscopy reconstructs protein structures from the relative orientation of the nuclear spins of hydrogen and other atoms. “Para hydrogen has successfully been used to enhance the sensitivity of the NMR method,” says Horke. “Thus, enriching para water in a protein’s water shell could become an interesting approach to improve NMR spectroscopy of these biological systems due to an almost natural environment.”

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Hubble Finds Companion Star Hidden for 21 Years in a Supernova's Glare

Hubble Finds Companion Star Hidden for 21 Years in a Supernova's Glare | Amazing Science | Scoop.it

Astronomers using NASA's Hubble Space Telescope have discovered a companion star to a rare type of supernova. This observation confirms the theory that the explosion originated in a double-star system where one star fueled the mass-loss from the aging primary star.


This detection is the first time astronomers have been able to put constraints on the properties of the companion star in an unusual class of supernova called Type IIb. They were able to estimate the surviving star's luminosity and mass, which provide insight into the conditions that preceded the explosion.


"A binary system is likely required to lose the majority of the primary star's hydrogen envelope prior to the explosion. The problem is that, to date, direct observations of the predicted binary companion star have been difficult to obtain since it is so faint relative to the supernova itself," said lead researcher Ori Fox of the University of California (UC) at Berkeley.


Astronomers estimate that a supernova goes off once every second somewhere in the universe. Yet they don't fully understand how stars explode. Finding a "smoking gun" companion star provides important new clues to the variety of supernovae in the universe. "This is like a crime scene, and we finally identified the robber," quipped team member Alex Filippenko, professor of astronomy at UC Berkeley. "The companion star stole a bunch of hydrogen before the primary star exploded."


The explosion happened in the galaxy M81, which is about 11 million light-years away from Earth in the direction of the constellation Ursa Major (the Great Bear). Light from the supernova was first detected in 1993, and the object was designated SN 1993J. It was the nearest known example of this type of supernova, called a Type IIb, due to the specific characteristics of the explosion. For the past two decades astronomers have been searching for the suspected companion, thought to be lost in the glare of the residual glow from the explosion.


Observations made in 2004 at the W.M. Keck Observatory on Mauna Kea, Hawaii, showed circumstantial evidence for spectral absorption features that would come from a suspected companion. But the field of view is so crowded that astronomers could not be certain if the spectral absorption lines were from a companion object or from other stars along the line of sight to SN 1993J. "Until now, nobody was ever able to directly detect the glow of the star, called continuum emission," Fox said.


The companion star is so hot that the so-called continuum glow is largely in ultraviolet (UV) light, which can only be detected above Earth's absorbing atmosphere. "We were able to get that UV spectrum with Hubble. This conclusively shows that we have an excess of continuum emission in the UV, even after the light from other stars has been subtracted," said team member Azalee Bostroem of the Space Telescope Science Institute (STScI), in Baltimore, Maryland.

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Flashes of light in particularly sensitive quantum states can be transmitted through the atmosphere

Flashes of light in particularly sensitive quantum states can be transmitted through the atmosphere | Amazing Science | Scoop.it

New prospects for secure data traffic: Flashes of light in particularly sensitive quantum states can be transmitted through the atmosphere. Erlangen-based physicists have sent bright pulses in sensitive quantum states through the window of a technical services room on the roof of the Max Planck Institute for the Science of Light to a building of the University Erlangen-Nürnberg.


It could be difficult for the NSA to hack encrypted messages in the future – at least if a technology being investigated by scientists at the Max Planck Institute for the Science of Light in Erlangen and the University Erlangen-Nürnberg will be successful: quantum cryptography. The physicists are now laying the foundation to make this technique, which can already be used for the generation of secret keys, available for a wider range of applications. They are the first scientists to send a pulse of bright light in a particularly sensitive quantum state through 1.6 kilometers of air from the Max Planck Institute to a University building. This quantum state, which they call squeezed, was maintained, which is something many physicists thought to be impossible. Using flashes of bright light for quantum communication through the atmosphere would have several advantages compared to the technique usually used today: it allows the photon packets to be transmitted in sunlight, something that is challenging with individual photons. Moreover, the receivers required for this are already presently in use for optical telecommunication via fibre optics and also via satellite.


Eavesdropping on a message protected by quantum cryptography cannot be done without being noticed. This is because quantum physics prevents a spy from reading a key which is encoded by specific quantum states without influencing these states. This can be exploited in a clever procedure for exchanging the key with which the data is encrypted, so that an unwelcome listener is not only detected, but is also prevented from accessing the information.


The quantum-protected communication is a fragile thing, however, and easily disturbed. All the more remarkable is the work of the Erlangen-based scientists working with Gerd Leuchs, Director at the Max Planck Institute for the Science of Light and professor at the University Erlangen-Nürnberg: "We have now succeeded in transmitting a flash of light, namely a pulse which contains many photons, through the atmosphere in a particularly sensitive quantum state," says Christian Peuntinger, who played an important role in the project. He and his colleagues sent a photon packet in a straight line from the roof of the Max Planck Institute in Nuremberg to the building of the University Erlangen-Nürnberg some 1.6 kilometers away. "This even works in broad daylight," says Christian Peuntinger.

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Nerve impulses can collide and but still continue unaffected

Nerve impulses can collide and but still continue unaffected | Amazing Science | Scoop.it

According to the traditional theory of nerves, two nerve impulses sent from opposite ends of a nerve annihilate when they collide. New research from the Niels Bohr Institute now shows that two colliding nerve impulses simply pass through each other and continue unaffected. This supports the theory that nerves function as sound pulses. The results are published in the scientific journal Physical Review X.

Nerve signals control the communication between the billions of cells in an organism and enable them to work together in neural networks. But how do nerve signals work?

In 1952, Hodgkin and Huxley introduced a model in which nerve signals were described as an electric current along the nerve produced by the flow of ions. The mechanism is produced by layers of electrically charged particles (ions of sodium and potassium) on either side of the nerve membrane that change places when stimulated. This change in charge creates an electric current.


This model has enjoyed general acceptance. For more than 60 years, all medical and biology textbooks have said that nerves function is due to an electric current along the nerve pathway. However, this model cannot explain a number of phenomena that are known about nerve functionResearchers at the Niels Bohr Institute at the University of Copenhagen have now conducted experiments that raise doubts about this well-established model of electrical impulses along the nerve pathway.

"According to the theory of this ion mechanism, the electrical signal leaves an inactive region in its wake, and the nerve can only support new signals after a short recovery period of inactivity. Therefore, two electrical impulses sent from opposite ends of the nerve should be stopped after colliding and running into these inactive regions," explains Thomas Heimburg, Professor and head of the Membrane Biophysics Group at the Niels Bohr Institute at the University of Copenhagen.


Thomas Heimburg and his research group conducted experiment in the laboratory using nerves from earthworms and lobsters. The nerves were removed and used in an experiment in which allowed the researchers to stimulate the nerve fibres with electrodes on both ends. Then they measured the signals en route.


"Our study showed that the signals passed through each other completely unhindered and unaltered. That's how sound waves work. A sound wave doesn't stop when it meets another sound wave. Both waves continue on unimpeded. The nerve impulse can therefore be explained by the fact that the pulse is a mechanical wave in the form of a sound pulse, a soliton, that moves along the nerve membrane," explains Thomas Heimburg. When the sound pulse moves through the nerve pathway, the membrane changes locally from a liquid to a more solid form. The membrane is compressed slightly, and this change leads to an electrical pulse as a consequence of the piezoelectric effect. "The electrical signal is thus not based on an electric current but is caused by a mechanical force," points out Thomas Heimburg.

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'Solid' light could compute previously unsolvable problems

'Solid' light could compute previously unsolvable problems | Amazing Science | Scoop.it
Researchers at Princeton University have begun crystallizing light as part of an effort to answer fundamental questions about the physics of matter.


The researchers are not shining light through crystal – they are transforming light into crystal. As part of an effort to develop exotic materials such as room-temperature superconductors, the researchers have locked together photons, the basic element of light, so that they become fixed in place.


"It's something that we have never seen before," said Andrew Houck, an associate professor of electrical engineering and one of the researchers. "This is a new behavior for light."


The results raise intriguing possibilities for a variety of future materials. But the researchers also intend to use the method to address questions about the fundamental study of matter, a field called condensed matter physics.

"We are interested in exploring – and ultimately controlling and directing – the flow of energy at the atomic level," said Hakan Türeci, an assistant professor of electrical engineering and a member of the research team. "The goal is to better understand current materials and processes and to evaluate materials that we cannot yet create."


The team's findings, reported online on Sept. 8 in the journal Physical Review X, are part of an effort to answer fundamental questions about atomic behavior by creating a device that can simulate the behavior of subatomic particles. Such a tool could be an invaluable method for answering questions about atoms and molecules that are not answerable even with today's most advanced computers.


In part, that is because current computers operate under the rules of classical mechanics, which is a system that describes the everyday world containing things like bowling balls and planets. But the world of atoms and photons obeys the rules of quantum mechanics, which include a number of strange and very counterintuitive features. One of these odd properties is called "entanglement" in which multiple particles become linked and can affect each other over long distances.

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Interactive dark matter could explain Milky Way’s missing satellite galaxies

Interactive dark matter could explain Milky Way’s missing satellite galaxies | Amazing Science | Scoop.it

Scientists believe they have found a way to explain why there are not as many galaxies orbiting the Milky Way as expected. Computer simulations of the formation of our galaxy suggest that there should be many more small galaxies around the Milky Way than are observed through telescopes. This has thrown doubt on the generally accepted theory of cold dark matter, an invisible and mysterious substance that scientists predict should allow for more galaxy formation around the Milky Way than is seen.


Now cosmologists and particle physicists at theInstitute for Computational Cosmology and the Institute for Particle Physics Phenomenology, at Durham University, working with colleagues at LAPTh College & University in France, think they have found a potential solution to the problem.


Writing in the journal Monthly Notices of the Royal Astronomical Society, the scientists suggest that dark matter particles, as well as feeling the force of gravity, could have interacted with photons and neutrinos in the young Universe, causing the dark matter to scatter.


Scientists think clumps of dark matter – or haloes – that emerged from the early Universe, trapped the intergalactic gas needed to form stars and galaxies. Scattering the dark matter particles wipes out the structures that can trap gas, stopping more galaxies from forming around the Milky Way and reducing the number that should exist.


Lead author Dr Celine Boehm, in the Institute for Particle Physics Phenomenology at Durham University, said: "We don’t know how strong these interactions should be, so this is where our simulations come in."


"By tuning the strength of the scattering of particles, we change the number of small galaxies, which lets us learn more about the physics of dark matter and how it might interact with other particles in the Universe."


"This is an example of how a cosmological measurement, in this case the number of galaxies orbiting the Milky Way, is affected by the microscopic scales of particle physics."


There are several theories about why there are not more galaxies orbiting the Milky Way, which include the idea that heat from the Universe’s first stars sterilised the gas needed to form stars. The researchers say their current findings offer an alternative theory and could provide a novel technique to probe interactions between other particles and cold dark matter.


Co-author Professor Carlton Baugh said: "Astronomers have long since reached the conclusion that most of the matter in the Universe consists of elementary particles known as dark matter." "This model can explain how most of the Universe looks, except in our own backyard where it fails miserably."


"The model predicts that there should be many more small satellite galaxies around our Milky Way than we can observe." "However, by using computer simulations to allow the dark matter to become a little more interactive with the rest of the material in the Universe, such as photons, we can give our cosmic neighbourhood a makeover and we see a remarkable reduction in the number of galaxies around us compared with what we originally thought."


The calculations were carried out using the COSMA supercomputer at Durham University, which is part of the UK-wide DiRAC super-computing framework.

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New study revisits Miller-Urey experiment at the quantum level with the aid of computers

New study revisits Miller-Urey experiment at the quantum level with the aid of computers | Amazing Science | Scoop.it
For the first time, researchers have reproduced the results of the Miller-Urey experiment in a computer simulation, yielding new insight into the effect of electricity on the formation of life's building blocks at the quantum level.


In 1953, American chemist Stanley Miller had famously electrified a mixture of simple gas and water to simulate lightning and the atmosphere of early Earth. The revolutionary experiment—which yielded a brownish soup of amino acids—offered a simple potential scenario for the origin of life's building blocks. Miller's work gave birth to modern research on pre-biotic chemistry and the origins of life.


For the past 60 years, scientists have investigated other possible energy sources for the formation of life's building blocks, including ultra violet light, meteorite impacts, and deep sea hydrothermal vents.


In this new study, Antonino Marco Saitta, of the Université Pierre et Marie Curie, Sorbonne, in Paris, France and his colleagues wanted to revisit Miller's result with electric fields, but from a quantum perspective.


Saitta and study co-author Franz Saija, two theoretical physicists, had recently applied a new quantum model to study the effects of electric fields on water, which had never been done before. After coming across a documentary on Miller's work, they wondered whether the quantum approach might work for the famous spark-discharge experiment.


The method would also allow them to follow individual atoms and molecules through space and time—and perhaps yield new insight into the role of electricity in Miller's work.


"The spirit of our work was to show that the electric field is part of it," Saitta said, "without necessarily involving lightning or a spark."  Another key insight from their study is that the formation of some of life's building blocks may have occurred on mineral surfaces, since most have strong natural electric fields.


"The electric field of mineral surfaces can be easily 10 or 20 times stronger than the one in our study," Saitta said. "The problem is that it only acts on a very short range. So to feel the effects, molecules would have to be very close to the surface." "I think that this work is of great significance," said François Guyot, a geochemist at the French Museum of Natural History.


"Regarding the mineral surfaces, strong electric fields undoubtedly exist at their immediate proximity. And because of their strong role on the reactivity of organic molecules, they might enhance the formation of more complex molecules by a mechanism distinct from the geometrical concentration of reactive species, a mechanisms often proposed when mineral surfaces are invoked for explaining the formation of the first biomolecules."


One of the leading hypotheses in the field of life's origin suggests that important prebiotic reactions may have occurred on mineral surfaces. But so far scientists don't fully understand the mechanism behind it.

"Nobody has really looked at electric fields on mineral surfaces," Saitta said. "My feeling is that there's probably something to explore there."

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Oxytricha trifallax breaks its own DNA into a quarter-million pieces and rapidly reassemble those for mating

Oxytricha trifallax breaks its own DNA into a quarter-million pieces and rapidly reassemble those for mating | Amazing Science | Scoop.it

Life can be so intricate and novel that even a single cell can pack a few surprises, according to a study led by Princeton University researchers. The pond-dwelling, single-celled organism Oxytricha trifallax has the remarkable ability to break its own DNA into nearly a quarter-million pieces and rapidly reassemble those pieces when it's time to mate, the researchers report in the journal Cell.


The organism internally stores its genome as thousands of scrambled, encrypted gene pieces. Upon mating with another of its kind, the organism rummages through these jumbled genes and DNA segments to piece together more than 225,000 tiny strands of DNA. This all happens in about 60 hours.


The organism's ability to take apart and quickly reassemble its own genes is unusually elaborate for any form of life, explained senior author Laura Landweber, a Princeton professor of ecology and evolutionary biology. That such intricacy exists in a seemingly simple organism accentuates the "true diversity of life on our planet," she said.


"It's one of nature's early attempts to become more complex despite staying small in the sense of being unicellular," Landweber said. "There are other examples of genomic jigsaw puzzles, but this one is a leader in terms of complexity. People might think that pond-dwelling organisms would be simple, but this shows how complex life can be, that it can reassemble all the building blocks of chromosomes."


From a practical standpoint, Oxytricha is a model organism that could provide a template for understanding how chromosomes in more complex animals such as humans break apart and reassemble, as can happen during the onset of cancer, Landweber said. While chromosome dynamics in cancer cells can be unpredictable and chaotic, Oxytricha presents an orderly step-by-step model of chromosome reconstruction, she said.


"It's basically bad when human chromosomes break apart and reassemble in a different order," Landweber said. "The process in Oxytricha recruits some of the same biological mechanisms that normally protect chromosomes from falling apart and uses them to do something creative and constructive instead."


Gertraud Burger, a professor of biochemistry at the University of Montreal, said that the "rampant and diligently orchestrated genome rearrangements that take place in this organism" demonstrate a unique layer of complexity for scientists to consider when it comes to studying an organism's genetics.


"This work illustrates in an impressive way that the genetic information of an organism can undergo substantial change before it is actually used for building the components of a living cell," said Burger, who is familiar with the work but had no role in it.


"Therefore, inferring an organism's make-up from the genome sequence alone can be a daunting task and maybe even impossible in certain instances," Burger said. "A few cases of minor rearrangements have been described in earlier work, but these are dilettantes compared to [this] system."

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