Anthropologists are pretty sure that Neandertals and humans interbred — and DNA analysis backs up this idea. But we don't know the date ranges involved — including when the two groups stopped hooking up.

A new study is offering some possible answers, indicating that Upper Paleolithic humans coming out of Africa stopped interbreeding with Neandertals about 47,000 years ago — which may have been before humans started to spread across the rest of Eurasia.

Neandertals reached Eurasia first. Our best estimates suggest that they first emerged in that part of the world roughly 230,000 years ago. Humans, on the other hand, made our first appearance in Africa over 200,000 years ago and we didn't start making our way up into the European continent until about 100,000 years ago.

Scientists are not exactly sure when the interbreeding between the two species first got started, speculating that it may have happened as early as when our mutual ancestors co-mingled in Africa. Genetic analysis, however, suggests otherwise.

Back in 2010, scientists successfully sequenced the Neandertal genome by using DNA from a well-preserved specimen. Analysis revealed that Neandertal DNA comprises anywhere from 1 to 4 percent of modern Eurasian genomes. Africans, on the other hand, don't share this genetic ancestry. Subsequently, the two prevailing theories suggest modern humans and Neandertals started interbreeding in Europe about 100,000 years ago, or that African populations ancestral to both Neandertals and modern humans remained subdivided over a few hundred thousand years, but then started breeding with Neandertals as they made their way into Europe during the Upper Paleolithic era.

To help solve this mystery, Sriram Sankararaman and David Reich measured the length of DNA pieces in the genomes of Europeans that are similar to Neandertals. When egg and sperm cells are formed, the strands of DNA within them form new combinations of genetic material. This process decreases the length of the chunks in each generation, thus allowing the geneticists to determine when the two populations last shared genes.

Based on their analysis, the scientists concluded that Neandertals and modern humans last exchanged genes anywhere between 37,000 and 86,000 years ago (with 47,000 years ago being the most likely). This is well after modern humans appeared outside of Africa, but likely before they spread east into Asia. The study strongly indicates, therefore, that Neandertals did have children with the direct ancestors of non-Africans.

You can read the entire study in PLOS.

Top image. Inset image.

Among the many things that can be said about science fiction, there's no question about its tremendous entertainment value and ability to convey difficult concepts in a clear and compelling manner. Which is why a pair of researchers from the University of Valencia are urging educators to get their act together and start using science fiction as a way to engage their students and motivate interest in science and technology.

An important teaching tool

To get a better sense of science fiction's current place in the classroom, researchers Fanny Petit and Jordi Solbes reviewed over 30 compulsory science and technology textbooks for physics, chemistry, biology, geology, and various technology subjects. They also took a look at teacher books, CD-ROMs, and activity books.

Of these resources, only 30% made any kind of reference to a scifi story or concept — neither through images, comments, texts, activities, or web references.

And of the resources that did, the references were fairly limited in scope, including a photo of Superman in the context of jadarite, a mineral whose chemical formula is similar to kryptonite. Similarly, they found a reference to the starship Enterprise in conjunction with a section on energy and distances, as well as a reference to the spinning space station of 2001: A Space Odyssey as a way to help explain centrifugal gravitational forces.

"Since textbooks make up the bulk of what is taught, this tells us that, along with the scarce number of activities proposed by teaching staff, science fiction is hardly present in the classroom despite it being viewed positively by teachers," noted the researchers through a press release.

Indeed, nearly 40% of teachers admitted that science fiction references improve motivation in students, leading to a greater interest in science and technology subjects. Yet, it remains relatively unused as a teaching tool.

Some science fiction is not helping

Since science fiction especially appeals to the teenage set, the researchers also wanted to get a sense of science fiction knowledge among students. They administered a questionnaire to 173 students at four different state and grant-maintained schools both in rural and urban areas.

In total, the students listed over 578 different titles, the leaders being Stars Wars (90), The Matrix (60), X-Men (41), I Robot (36), Spiderman (32) and The Day after Tomorrow (24).

But they also listed titles that were clearly not of the science fiction realm, a potential indication of their confusion about the genre — or more perniciously, their limited understanding of science. Specifically, the students listed such movies and books as Harry Potter, The Lord of the Rings (those two alone garnered 59 and 50 hits), Neverending Story, and Mission Impossible.

The questionnaire also assessed the students' impression of science fiction. Some 24% of the participants looked at science favorably, while 31% were able to speak about advances in both science and technology. Nearly half of them had a positive outlook when it came to scientists, while 35% had a "distorted" or "exaggerated" impression, while the remaining 12% didn't care for them at all. In terms of the latter two classifications, the students felt that some scientists conform to the "mad scientist" category, that they are "selfish," "they spend their life in the lab," and are "people who want to rule the world".

In terms of an explanation, the researchers noted that scientists very rarely make appearances in the most popular films. And when they do, they're typically portrayed as the supervillans. "In these films, the antagonist is usually the crazy scientist that wants to rule the world or even increase their power after finding a powerful 'weapon'," noted the researchers.

Perhaps the popularization of more positive scientifically-inclined role models would be in order.

Top image. Inset images here and here.

Oh, oh, looks like Curiosity has just stumbled upon a shiny object that NASA scientists believe might be a fallen part of the rover. Or it could be a piece of debris that fell from the landing mechanisms. Or something else? NASA isn't quite sure, so they've temporarily stopped scooping the surface until they get a better sense of what it is.

From NASA's JPL:

Curiosity's first scooping activity appeared to go well on Oct. 7. Subsequently, the rover team decided to refrain from using the rover's robotic arm on Oct. 8 due to the detection of a bright object on the ground that might be a piece from the rover. Instead of arm activities during the 62nd Martian day, or sol, of the mission, Curiosity is acquiring additional imaging of the object to aid the team in identifying the object and assessing possible impact, if any, to sampling activities.

Of course, this was a perfect opportunity for the SarcasticRover (not the real @marscuriosity) to put out a few jabs via Twitter.

Among the many things that computer science pioneer Alan Turing is remembered for was his tremendous contribution to the British war effort in which he is credited with cracking Nazi Germany's Enigma code — a breakthrough that historians widely agree helped to shorten the war in Europe. But now, the Polish government is claiming that Bletchley Park's achievement would have been impossible without the contributions of Polish cryptographers who had been working on the problem since the early 1930s. The time has come, they say, to give credit where credit is due.

And indeed, the Polish government has a strong case.

Back in 1932, Poland assembled the Polish Cipher Bureau in response to what they perceived to be the rising German threat. Among the cryptographers hired, they recruited three young mathematicians, Marian Rejewski, Henryk Zygalski, and Jerzy Różycki. The team was charged with the task of solving the logical structure of the military Enigma, a 3-rotor machine whose security was increased in 1930 by the addition of a plugboard.

To help them in their work, the French Military Intelligence provided the Polish bureau with two German documents and two pages of Enigma daily keys. The items had been stolen by a French spy who worked at Germany's Cipher Office in Berlin.

With these clues, Rejewski was able to crack the code using the mathematical theory of permutations and groups — along with a lucky guess that the non-commercial version of the Enigma typewriter featured keys in alphabetical order. Subsequently, the Polish cryptographers were able to construct 'Enigma doubles' to help them transcribe coded messages. In all, they devised three different methods for breaking the encrypted codes produced on the Enigma machine.

However, just prior to the onset of the war, the Germans added another two rotors to the system, increasing the possible wheel orders from 6 to 60. The Poles were still able to read a small minority of messages, but they clearly needed to solve the new rotors.

Time, however, was not on their side. Once the German invasion of Poland became imminent in 1939, the Polish government handed over all their research (including an Enigma machine) to the British in hopes that they would continue their work. Which they most certainly did, resulting in the full cracking of the Enigma code during the early stages of World War II.

And for which Britain has claimed virtually all of the credit.

But now, frustrated with what they see as a terrible injustice and oversight, the Polish government has put forth a motion in parliament to pass a resolution praising Rejewski, Zygalski, and Różycki for their contributions, while also designating them as official heroes of the state. The resolution reads, "In both popular literature and official information the public was told that the breaking of the Enigma codes was due to the work of the British intelligence services to the complete omission of the work of Polish scientists."

And indeed, the head start that Poland gave to Turing and Bletchley Park cannot be overstated. While there's no doubt that British cryptographers still had lots of work to do after coming into the possession of this information, it's fair to say that they might not have solved Enigma without it. As Polish senator Piotr Zientarski has said, "We have a duty to remind people just what the Polish cryptologists did."

Source: Telegraph. Top image via; inset images via.

Paleontologists have discovered beautifully preserved species trapped in amber before — but this one is extraordinary. It features a parasitic wasp that has become ensnared in a spider's web, with the owner bearing down on it for an attack. But just before the spider was about to have its meal, a drop of resin flowed down from above, freezing the moment in time.

Researchers date the scene to the Early Cretaceous between 97 to 110 million years ago in the Hukawng Valley of Myanmar — a time when dinosaurs would have most certainly been in the neighborhood. And in addition to the dramatic scene, the fossil also contains the body of a male spider in the same web — the first evidence of spider social behavior in the paleontological record.

Spider sociality still exists in some species, but it is very rare. Today, most spiders live solitary lives, often resorting to cannibalism — including males who often attack immature species in the same web.

But as for catching unsuspecting prey in a web, that appears to be an evolutionary strategy that has survived the test of time. And in fact, spiders are an ancient invertebrate that first emerged about 200 million years ago. The oldest fossilized record of a spider dates back to 130 million years ago. This recent discovery is considered the first and only fossilized example of a spider attack on prey caught in its web.

The specimen trapped in the resin is an orb-weaver spider, a social species that has now been described by the researchers in their new paper which appears in Historical Biology. As for the wasp, it's closely related to a species that still exists today — one that is known to parasitize spider and insect eggs.

It would seem that the wasp had it coming.

Image: OSU College of Science.

Noah Iliinsky, an expert in data visualization and communications, has put together what he calls a "spoiler-ific timeline" for Looper in which he charts all the various paths taken by the film's characters. But as Iliinsky notes, it also shows how the film defies standard time-travel conventions. Now, the diagram does indeed contain spoilers, so you have been duly warned.

Iliinsky argues that there are basically two kinds of time-travel stories, those that feature an immutable past (where events cannot be altered) and those that feature a malleable history (in which previous events can be altered, thus spawning an entirely new set of timelines).

But Looper, says Iliinsky is a time-travel movie that "keeps us guessing with aspects of both archetypal plotlines." He writes:

Regardless of how we classify it, the key question Looper presents is: Can modifying the past significantly affect the future, or are some outcomes inevitable? While some aspects of the film clearly indicate that we can change our futures by changing our pasts, the open question we're left with is whether Joe really is able to successfully alter a probable future?

Source: UnderWire.

We've known about the effects of climate change for decades now, but the past few years (and even months) have been particularly revealing. This past year, for instance, we've seen arctic sea ice levels reach an historic low, while the United States has experienced its worst wildfire season on record (not to mention all the new temperature records). In these desperate times we may have to call upon desperate measures, including any number of proposed geoengineering projects. But as Gaia Vince of BBC Future recently pointed out, the solution may simply involve the improvement of an existing "carbon capture" technology: The humble tree.

Indeed, plants are nature's way of pulling carbon dioxide from the atmosphere. Subsequently, many ecologists have suggested that we simply plant more trees and other foliage. But as Vince notes, there are limits to such plans, including the high demand for agricultural space.

Instead, Vince points to the work of Klaus Lackner, director of the Lenfest Center for Sustainable Energy at Columbia University, who has designed an artificial tree that absorbs CO2 from the air using "leaves" that are 1,000 times more efficient than the real thing — but at the same time does not require exposure to sunlight.

Vince writes:

The leaves look like sheets of papery plastic and are coated in a resin that contains sodium carbonate, which pulls carbon dioxide out of the air and stores it as a bicarbonate (baking soda) on the leaf. To remove the carbon dioxide, the leaves are rinsed in water vapour and can dry naturally in the wind, soaking up more carbon dioxide.

Lackner calculates that his tree can remove one tonne of carbon dioxide a day. Ten million of these trees could remove 3.6 billion tonnes of carbon dioxide a year – equivalent to about 10% of our global annual carbon dioxide emissions. "Our total emissions could be removed with 100 million trees," he says, "whereas we would need 1,000 times that in real trees to have the same effect."

As for what should be done with the resulting stores of CO2, Lackner suggests that it be converted into liquid fuels to power vehicles. And indeed, carbon dioxide produces carbon monoxide and hydrogen when it reacts with water — a solution known as syngas on account of its ability to be converted into hydrocarbon fuels like methanol or diesel. Again, Vince writes:

We have the technology to suck carbon dioxide out of the air – and keep it out – but whether it is economically viable is a different question. Lackner says his trees would do the job for around $200 per tonne of removed carbon dioxide, dropping to $30 a tonne as the project is scaled up. At that price – which has been criticised as wildly optimistic (the American Physical Society's most optimistic calculations for direct air capture are $600 per tonne of carbon dioxide removed, although the UK's Met Office is more favourable) – it starts to make economic sense for oil companies who would pay in the region of $100 per tonne to use the gas in enhanced oil recovery.

As Vince correctly points out, Lackner's plan is indeed very expensive. But that said, it is a plan — and one that sounds rather elegant. In terms of the costs, that will have to be offset against the prospect of doing nothing.

Be sure to read all of Gaia Vince's article as she goes over more of the details.

Image via Shutterstock.com/angelo lano. Inset image via.

Back in July we reported on a new theory explaining why both Pioneers 10 and 11 were decelerating at a rate that seemed to defy Newtonian physics. The answer, it seemed, had to do with heat from the electrical subsystems and the decay of plutonium which was pushing back on the craft. But now, a researcher from the University of Missouri says this is wrong — and that our unexpected measurements of the Pioneer probes can be explained by taking the ongoing expansion of the universe into account.

According to Sergei Kopeikin, the previous explanation for the so-called Pioneer anomaly was only able to account for 15 to 20% of the observed deceleration. Kopeikin, on the other hand, devised a new set of calculations which factored in the expansion of the universe — including the way it affects the movement of photons that make up light and radio waves.

In order to measure the speed of the spacecraft, NASA scientists transmitted beams of radio waves to the object, and waited for their return to Earth after bouncing back (what's called Doppler-tracking). The speed of the probes could thus be determined by measuring the time it took for the photons to make a complete round trip. But what Kopeikin observed was that the phontons were moving at a different rate than predicted by Newtonian theory — what gave the impression of deceleration.

In other words, the Pioneer spacecrafts aren't slowing down — they're moving exactly as the physical laws would predict. But because space is expanding, and because the Pioneer probes are so far away, we've been getting the false sense that they're slowing down. Physicists, it now appears, haven't been plugging in all the relevant variables into their calculations.

Consequently, Kopeikin's discovery (and his new calculations) will change the way that physicists measure the speed of objects at extreme distances — including possible interstellar trips made by future humans.

The entire study can be found at Physical Review D.

Top image via lcas-astronomy. Inset image via NASA.

Scientists recently discovered that caffeine consumption can be tied to a reduced risk of Alzheimer's disease and other neurodegenerative disorders. They knew that it was suppressing the rise of amyloid plaques in the brain, but why coffee consumption did the trick remained a mystery. But now, researchers from the University of Illinois believe they have found the answer, and it has to do with caffeine's ability to block inflammation in the brain — a discovery that could lead to new drugs which can prevent — or even reverse — mild cognitive impairment.

Hypoxic mice on caffeine

The study, which appears the Journal of Neuroscience, was conducted by Gregory Freund, a professor at U of I's College of Medicine. To reach his conclusion, Freund conducted an experiment on two groups of mice — one that was administered caffeine, and one that was not. Then, in order to facilitate cognitive impairment, he interrupted the breathing and blood flow of the mice (what's called hypoxia). He gave the mice a chance to recover, and then measured their ability to form new memories.

What Freund discovered was that, of the mice who consumed caffeine, they recovered their ability to form a new memory 33% faster than those mice who did not get the caffeine. This was a particularly pronounced effect — one that matched the anti-inflammatory impact of blocking IL-1 signalling — what has been implicated in the inflammation associated with Alzheimer's disease.

Blocking adenosine receptors

To better understand how caffeine was actually helping to reduce this inflammation, Freund considered the nature of the brain damage itself. What he discovered was that hypoxia kickstarts a complicated chain reaction that ends in cognitive decline. Caffeine, it now appears, minimizes the impacts of this chain reaction.

Hypoxia releases adenosine onto brain cells — and this is not good; adenosine molecules are what makes up ATP — the fuel that powers brain cells. What's essentially happening by virtue of the hypoxia is that this fuel is leaking all over the place — what Freund compares to highly volatile gasoline leaking out of a tank and threatening everything in its immediate surroundings.

This leaked adenosine triggers the activation of the caspase-1 enzyme, which in turn sets off the production of beta cytokine IL-1 — what is known to be a major player in inflammation.

But as Freund's study revealed, this cascade of despair is lessened by caffeine's ability to block adenosine receptors. In turn, this results in the brain's ability to stave of inflammation when confronted with either hypoxic effects or neurodegenerative disorders like Alzheimer's.

The entire study can be read at the Journal of Neuroscience.

Image: NOBUHIRO ASADA/Shutterstock.com.

Public speaking is one of our most common fears, topping flying, financial ruin, sickness, and even death. The fear can get so bad that people become physically ill before getting on stage. But this fear — often called performance anxiety or stage fright — extends beyond the pressure to perform in the moment. It's about the underlying social psychology of exposing oneself to an audience. It's this vulnerability that sets off an entire cascade of physiological processes throughout the body in a defense mechanism that at one time served an important evolutionary purpose.

Understanding the science of stage fright can also help ease the fear.

A common fear

Back in 2007, I gave a talk at a futurist conference in Chicago that featured such speakers as Ray Kurzweil, William Shatner, and Peter Diamandis of XPrize fame. If this wasn't pressure enough, the day before my presentation I learned that one of my longtime heros, cognitive scientist Marvin Minsky, was going to be in the audience. It was at this point that my body started to rebel against me; I broke out into a nasty rash, began vomiting, and contracted a rather unpleasant case of diarrhea. The next day, I stood on the stage and desperately fought back the urge to panic, delivering a presentation that was stilted, awkward, and completely uninspiring.

Sadly, this was typical for me back then. But this experience finally made me snap out of my denial: I have stage fright — and I have it bad. And I am hardly alone.

Celebrities with stage fright include Rod Stewart, Barbara Streisand, Mel Gibson, and Carol Burnett (who reportedly threw-up before many of her performances). Many prominent athletes tend to suffer from it as well, including nervous hockey goalies and boxers who just can't seem to perform when everything's on the line.

Generalized anxiety

Stage fright is an emotional and physical response that is triggered in some people when they need to perform in front of an audience — or even an anticipated or perceived audience (such as standing in front of a camera).

While feelings of stress and anxiety are present during the actual performances themselves, individuals with stage fright often start to experience its effects days or weeks in advance (something that was particularly bad in my case). Consequently, stage fright is more than just a fear that's elicited during a performance — it's also very much about the lead-up. And in fact, for some, the performance itself can be a kind of cathartic release from the tension.

In addition to inducing the emotional effects of generalized anxiety, people with stage fright also exhibit a diverse range of physiological symptoms, including dry mouth, butterflies in the stomach, a pounding heart, shaking of the extremities, sweaty hands, facial ticks, and diarrhea. But this is a partial list; people with stage fright can exhibit any number of symptoms.

Inner chatter

Like most phobias, stage fright is a perfectly normal and even natural response to situations that are perceived to be dangerous or somehow detrimental. Psychologists who work with stage fright patients describe how their inner chatter tends to focus on those things that could go wrong during the performance and in the immediate aftermath of a potential failure. For people who have it quite bad, this can amount to a kind of neuroticism in which fears are exaggerated completely out of context — what psychologists call chronic catastrophizing.

And in fact, studies have shown that these fears can be driven by any number of personality traits, including perfectionism, an ongoing desire for personal control, fear of failure and success, and an intense anxiety about not being able to perform properly when the time comes (which can often serve as a self-fulfilling prophecy). Psychologists have also observed that people with stage fright tend to place a high value on being liked and regarded with high esteem.

Moreover, during the performance itself, individuals with stage fright tend to form a mental representation of their external appearance and behavior as they presume it's being seen by the audience. Consequently, they turn their focus onto themselves and interpret the audience's attention as a perceived threat.

In turn, this perceived threat creates fear; people with performance anxiety start to think pessimistic thoughts and assume that others are naturally critical and that a negative evaluation is likely (again, these ideations can happen either prior to or during the performance).

And once the fear sets in, that's when individuals with stage fright begin their downward spiral during which they're perpetually on the lookout for anything that would reinforce their fears. For example, though most of the audience may in fact be enjoying the presentation or performance, the performer will only notice negative cues, such as audience members yawning, frowning, chuckling, and so on.

Evolutionary biologists believe there may be a good reason for stage fright to exist. In the past, these sorts of cues could have signaled the loss of status or access to resources. In turn, the situation would trigger the fear response, what is also known as fight-or-flight.

Fight-or-flight

And indeed, stage fright is an evolutionary throwback — one that can be directly tied to our more primal neurological heritage.

The fear that is elicited by stage fright ignites the body's fight-or-flight response, which is what brings about its various physiological manifestations. Essentially, it's the perceived sense of danger that sets off the sympathetic nervous system, which mobilizes the body's nervous system in preparation for something that arguably never comes.

Specifically, catecholamine hormones, like adrenaline or noradrenaline, prime the body for violent physical action. This includes accelerated breathing and heart rates, the halting of digestive processes, constriction of blood vessels, releasing fat and glucose to fuel muscles, and tunnel vision (to focus attention away from the peripheries).

Of course, the response is completely disproportionate, and can be seen as a kind of false alarm. And needless to say, the psychological experience of all this, including the initial fear-response itself, is extremely unpleasant. Stage fright, it's fair to say, is not fun.

Longer term effects include diminished sexual response (including an inability for males to get an erection), constipation, anorexia, and difficulty urinating. It also compromises the body's immune system, making it vulnerable to infections and other problems.

Treatments

Thankfully, there are a number of things that can be done about it.

For me, one of the best ways to deal with my stage fright has been to get on stage as much as possible — regardless of the discomfort. I find that the more public speaking I do, the less anxiety I feel. And indeed, the longer I go between talks, the worse the stage fright becomes.

Now that said, this may not be an option for people who suffer from debilitating performance anxiety. In some cases, there are safer and friendlier opportunities to perform publicly, including Toastmaster classes. Most cities offer similar courses and opportunities to help dancers and musicians.

Another option is medication. Beta blockers are renowned for their ability to counter the effects of the fight-or-flight response. The exact mechanism of action is largely unknown, but beta blockers like propranolol have been used by performers for decades (some surgeons even use it to reduce hand tremors during surgery).

In fact, surveys have shown that upwards of 27% of symphony orchestra musicians use beta blockers to help alleviate the symptoms of stage fright. They're also used in sports, though they have banned by the IOC and are considered a performance enhancing drug.

There's also cognitive behaviour therapy to consider. Unlike beta blockers, CBT gets people to tackle the psychological and emotional underpinnings of their stage fright to help them counter much of the negative internal talk that's associated with the condition. Specific techniques include recognizing irrational and unfounded beliefs, avoiding the revisitation of an "activating event" (i.e. a recent negative experience), and learning how not to obsess over the fear of negative consequences. And just simply talking it out with a therapist has also been shown to be effective.

Other treatment options include hypnosis, meditation, and visualization. Visualization techniques can be particularly effective (especially for athletes), as it creates an identifiable, positive image in a person's mind about the desired outcome. Mentally projecting oneself after the performance does much to alleviate feelings of anxiety. I've used visualization techniques before, and I find them quite helpful — including visualizations of everything that could possibly go wrong, which I then come to accept as possibilities (sounds unintuitive, but it works for me).

Now all this said, it's important to acknowledge a couple of things.

First, people with stage fright shouldn't feel that they have to get over it and force themselves into situations that make them feel exceedingly uncomfortable. Every person with performance anxiety needs to consider just how important it is to them to deal with the effects of stage fright. Sometimes it's just simply not worth it.

And second, stage fright is not really something that anyone can truly "get over." For me, it will always be there lingering in the background — I'm just getting better at managing it.

Sources: Schultz & Heimberg 2007, Conroy and Metzler 2004, Hewitt et al 1995, Rapee & Heimberg 1997, Trower & Gilbert 1989, Fridlund et al 2003, Osborne & Franklin 2010, Steptoe & Fidler 1987.

Top image: Clover/Shutterstock.com. Inset images: 1 | 2: Jose Gil/shutterstock | 3 | 4

Back in 2003, Oxford professor Nick Bostrom suggested that we may be living in a computer simulation. In his paper, Bostrom offered very little science to support his hypothesis — though he did calculate the computational requirements needed to pull of such a feat. And indeed, a philosophical claim is one thing, actually proving it is quite another. But now, a team of physicists say proof might be possible, and that it's a matter of finding a cosmological signature that would serve as the proverbial Red Pill from the Matrix. And they think they know what it is.

According to Silas Beane and his team at the University of Bonn in Germany, a simulation of the universe should still have constraints, no matter how powerful. These limitations, they argue, would be observed by the people within the simulation as a kind of constraint on physical processes.

So, how could we ever hope to identify these constraints? Easy: We just need build our own simulation of the universe and find out. And in fact, this is fairly close to what the physicists are actually trying to do. To that end, they've created an ultra-small version of the universe that's down to the femto-scale (which is even smaller than the nano-scale).

And to help isolate the sought-after signature, the physicists are simulating quantum chromodynamics (QCD), which is the fundamental force in nature that gives rise to the strong nuclear force among protons and neutrons, and to nuclei and their interactions. To replace the space-time continuum, they are computing tiny, tightly spaced cubic "lattices." They call this "lattice gauge theory" and it is subsequently providing new insights into the nature of matter itself.

Interestingly, the researchers consider their simulation to be a forerunner to more powerful versions in which molecules, cells, and even humans themselves might someday be generated. But for now, they're interested in creating accurate models of cosmological processes — and finding out which ones might represent hard limits for simulations.

To that end, they have investigated the Greisen–Zatsepin–Kuzmin limit (or GZK cut-off) as a candidate — a cut-off in the spectrum of high energy particles. The GZK cut-off is particularly promising because it behaves quite interestingly within the QCD model.

According to the Physics arXiv blog, this cut-off is well known and comes about when high energy particles interact with the cosmic microwave background, thus losing energy as they travel long distances. The researchers have calculated that the lattice spacing imposes some additional features on the spectrum, namely that the angular distribution of the highest energy components should exhibit cubic symmetry in the rest of the lattice (causing it to deviate significantly from isotropy).

"In other words," write the arXiv bloggers, "the cosmic rays would travel preferentially along the axes of the lattice, so we wouldn't see them equally in all directions."

And that would be the kind of reveal the physicists are looking for — an indication that there is indeed a man hiding behind the curtain.

And what's particularly fascinating about this is that we can make this measurement now with our current level of technology. As the researchers point out, finding this effect would be the same as 'seeing' the orientation of the lattice on which our own universe is simulated.

That said, the researchers caution that future computer models may utilize completely different paradigms, ones that are outside of our comprehension. Moreover, this will only work if the lattice cut-off remains consistent with what we see in nature.

At any rate, it's a remarkable suggestion — one that could serve as an important forerunner to further research and insights into this fasinating possibility.

The entire study can be found at Physics arXiv.

Top image via. Inset image courtesy Silas Beane.

There's little doubt that graphene is set to be the next big thing in materials technology. At a mere one atom thick, it is incredibly flexible, eternally stretchy, conductive, and self-cooling. And as time passes, we are truly getting a better sense of the possibilities, including such things as video screens as thin and flexible as paper, super-thin cybernetic devices that can be grafted onto living tissue, and electrically conductive transmitters that can repair damaged spinal columns.

In this new ChemMatters video, you'll see how graphene is constructed, how it works — and how something so incredibly thin can be 100 times stronger than steel.

As a future terraforming species, we take it for granted that Mars will be our first megaproject. But while transforming the Red Planet into something more hospitable for life seems the most logical — if not easiest — first step towards colonizing the solar system, it may actually make more sense to tackle our sister planet first. Because some scientists warn of a runaway greenhouse effect here on Earth, it may be prudent for us to terraform Venus first — a planet that has already undergone a carbon dioxide-induced apocalypse. And by doing so, we may learn how to prevent or reverse a similar catastrophe here on Earth.

Runaway greenhouse

One of the more frightening scenarios presented by climate scientists is the problem of a runaway greenhouse effect.

Should carbon emissions continue to increase at the current rate, they warn, we may hit a critical tipping point after which a positive feedback loop will be created between the surface of the Earth and the increasingly thick and opaque atmosphere above it. Hypothetically, the effect would instigate a rapid and progressively escalating rise in temperature that would eventually result in the extermination of all life on the planet and the evaporation of the oceans.

No one knows for sure if this will be the ultimate climax of human-caused global warming, but it's a possibility that clearly needs to be taken seriously. It's a genuine existential risk.

And disturbingly, there is precedent for this right here in our solar system. Scientists are quite certain that Venus went through a runaway greenhouse effect when it was young and when it still had oceans. In those early days, and as the sun got brighter, Venus's oceans began to boil and evaporate into the atmosphere, where it eventually leaked out into space. Today, and as a consequence, Venus has an absolutely massive amount of carbon dioxide in its atmosphere, the result of poor carbon recycling (which is facilitated by the presence of liquid water).

A veritable hell

As a result, Venus has essentially turned into hell. It features an average temperature of 467°C (872°F) — a temperature that's hot enough to melt lead. And its thick layer of carbon dioxide (CO2) bears down on the planet at a level 90 times greater than what we experience here on Earth.

To say that Venus has a lot of CO2 in its atmosphere would be a gross understatement. Over 96% of its atmosphere consists of CO2, which it displays prominently through its thick layer of clouds that float 50-70 km above the surface. Above that, is has clouds and mist that are comprised of concentrated sulphuric acid and gaseous sulfur dioxide (which is derived from the sulphuric acid).

Making matters worse, Venus gets about twice the sunlight than Earth, and it features a day that's 224 Earth days long (making its day longer than its year). Oh, and it doesn't have a magnetosphere to protect it against solar radiation.

After considering all this, it's fairly safe to suggest that the terraforming of Venus would pose a set of problems far greater than what would await us on Mars. But that isn't necessarily a valid reason to terraform Mars first. As already noted, the insights we would glean from a Venus terraforming project could serve us well given our climate change problems here on Earth. It's even fair to say that the simple exercise of thinking about it — the brainstorming of ideas — may help us deal with — and even acknowledge — our current climate crisis.

But Venus poses other advantages as well. It's closer than Mars, making it easier and quicker to travel back and forth. And like the Earth, it resides within the solar system's habitable zone. We also know it can hold an atmosphere (obviously), and it has nearly the same mass and size as Earth. Mars, on the other hand, is considerably smaller, and would pose serious health risks to humans (reduced muscle mass and bone density) on account of its low gravity.

Getting rid of the CO2

Should we decide to terraform Venus, or any planet for that matter, we need to accept the fact that a project of that magnitude would take a considerable amount of time. It would be a long term, generational project that would have to be rolled out over a series of phases. Thankfully, a number of visionareis have given us a head start in thinking about how we could do this.

The first step, it's fairly obvious to say, is that we'll need to get rid of the excess CO2.

Fifty years ago, Carl Sagan suggested that we use atmospheric-based GMO algae to convert the CO2 into something more benign or useful. It's not the greatest idea in the world, but give him credit — he was the first person to seriously suggest that we terraform Venus.

More recently, NASA engineer James Oberg proposed that all the CO2 could be blown out into space. Writing in his 1981 book, New Earths, he wrote:

If we wish to remove 98% of the mass of the Venusian atmosphere in a reasonable time, say, 100 years, we must haul up a mass 10 quintillion tons, or 300,000 tons per second. Compare that to the flow along the Amazon river...10,000 tons per second. The largest machines built which handle flowing water...handle 400 tons per second.

Or look at it from an energy requirement: hauling the mass of gas 100 km high, and then accelerating it by 20 km per second requires about 1025 ergs over a 100-year period. That's all the sunlight falling over the same period on an area of 10,000 square km assuming 100% efficiency...Throw in a factor of 10 for engineering reality, and the air scoopers must have an area of...three times the total area of Venus.

And in the 1990s, Paul Birch proposed a plan that would see Venus flooded with over 4x10¹⁹ kg of hydrogen. This would cause a reaction with the CO2, which would in turn produce graphite and water — a lot of water. His estimates predicted that about 80% of the surface area of Venus would eventually be covered in water (compared to Earth's 70%).

Other plans describe the capture of carbonates, direct liquefaction and sequestration, advanced nanotechnology, a megascale quicklime process, or a combination of some or all of these.

Temperature, rotation, and the magnetosphere

Once the CO2 problem is resolved, the next phases of Venus's transformation would likely involve addressing ongoing temperature problems, irregular planetary rotation, and the lack of a magnetosphere.

It's safe to assume that, by virtue of the elimination of the excess CO2, the temperature would start to get more reasonable. But it's still likely that Venus would experience temperatures much greater than what life can withstand.

Meteorologist Paul Crutzen, winner of the 1995 Nobel Prize in Chemistry, suggested a number of years ago that it would be possible to artificially release massive quantities of sulfur dioxide at an altitude of 20 kilometers in order to cool down surface temperatures and offset the growing greenhouse effect. This would be similar to the effect of volcanic eruption here on Earth.

Another possible solution proposed by Birch would be to place space-based mirrors at the lagrange point between Venus and the sun. Angled correctly, the mirrors would reflect the excess sunlight away from the planet, while simultaneously serving as solar power generators.

Alternately, the reflectors could be placed in the atmosphere or on the surface of Venus. Nanotechnology expert J. Storrs Hall has devised a weather machine for Earth that could essentially perform this task. There's no reason to believe that such a system couldn't also work for Venus. And given the planet's proximity to the sun, along with its agonizingly slow rotation, a long term technological solution will likely be mandatory.

And indeed, we might also want to readjust the spin of Venus to give it a rate more comparable to Earth's. Now this would truly be an epic task, requiring an absolutely tremendous amount of energy. In all likelihood, the only way to do it would be to introduce large celestial bodies around Venus in order to accelerate its rotation up from once every 224 Earth days. And in fact, it might just be simpler to arrange a series of massive mirrors to redirect sunlight to the dark side of the planet.

Finally, there's the problem of the magnetosphere — a complete deal breaker for the onset of life. It's possible that the slow rotation of Venus is to blame for this. Perhaps future technologists will devise a plan to create a virtual magnetosphere — one that can shield the planet from solar radiation and devastating solar storms.

A valuable thought experiment

It's clear that the terraforming of Venus will be hard. We may never get it to the point where life will be able to flourish — but it will be interesting to see the extent to which we could make it habitable for human occupation, along with synthetic life that could live under harsh conditions.

Perhaps the first step in the process, aside from taking the possibility seriously and conjuring novel ways to fix the planet, would be to create simulations of all these proposals to determine which ones would work best.

Moreover, these simulations would compliment similar models of what might happen to Earth given a similar set of circumstances. The quest to make Venus habitable for life, it would seem, just might ensure that Earth can continue to do the same.

Images: 1:NASA | 2 | 3 | 4 | 5: J. Storrs Hall

We're still very much in the early stages of introducing wearable technology to our wardrobes — but a newly developed medical device called the First Warning System is showcasing its incredible potential. Worn like a sports bra, and equipped with sensors, AI, and pattern recognition software, the device can reportedly detect angiogenic activity — cell temperature changes that are associated with breast cancer.

People have been trying to create a bra that detects breast cancer since the 1970s, when NASA Administrator James C. Fletcher and friends filed a patent for one. Now at last, it appears that this dream could become a reality.

From the company's website:

The system is a non-invasive breast physiology screening system, much more sensitive and much more cost effective than mammography. The platform has applications for both OB/GYN and primary care in-office use, as well as potential use as an over-the-counter (OTC) diagnostic system.

Three preliminary clinical studies in more than 650 women have been completed yielding compelling results, demonstrating an average accuracy of 92.1% (percentage of correct classification), an average sensitivity of 94.7% (true positive cases), and an average specificity of 91.1% (true negative cases). In comparison, the specificity and sensitivity of the gold standard mammogram averages 70% and the accuracy of interpretation is completely subject to the skill and ability of the reading radiologist.

Given that one in eight women will develop breast cancer in their lifetime, this "smart bra" is definitely a good idea — and an excellent indication of where wearable technology is headed.

H/t Medgadget.

Biotechnology is getting into some pretty interesting territory these days. The latest breakthrough comes from Kyoto University where research scientists have, for the first time, created a mouse by using eggs and sperm produced by stem cells alone. The achievement once again shows the remarkable possibilities presented by regenerative technologies like stem cells — but also the unsettling potential for human births in which parents might not be required.

Back in 2011, the same scientists, a team led by Mitinori Saitou, produced healthy mouse pups by using sperm derived from mouse stem cells. But if that wasn't remarkable enough, they have now shown that it's also possible to produce viable eggs with stem cells, too. And if just to prove a point, they used their stem cell-derived sperm to fertilize the stem cell-derived eggs to create baby mice.

Making eggs

To do so, they used mouse embryonic stem cells (ES) and induced pluripotent stem cells (iPS). These cells are undifferentiated — they are simply waiting for an indication as to what type of functional cell they should transform into. Prior to this breakthrough, however, scientists had a hard time creating germ cells (an embryonic cell with the potential of developing into a gamete). This has to do with the way that germ cells divide, namely through meiosis in which cells contain a single copy of each chromosome.

To overcome this problem, Saitou took the ES and iPS cells and cultured them into a mix of proteins to produce primordial germ cells, what they hoped would eventually turn into an oocyte. Following that, they mixed the proto-oocytes (what the researchers call primordial germ cell-like cells (PGCLCs)) with fetal ovarian cells, and scaffolded the structure by grafting them onto the natural ovaries within live mice.

A month later, the proto-oocytes had turned into proper oocytes, which were in turn fertilized in a petri dish with the stem cell-derived mouse sperm. The embryos were then implanted into a surrogate mother. The resulting pups turned out to be healthy — and in fact, they grew up to be fertile themselves.

Making human eggs

Moving forward, Saitou's group is trying to make the primordial cells from human tissue. It's thought that creating human sperm and eggs from embryonic stem cells will help scientists to better understand the reproductive process.

It's also thought that the technique could help both men and women who experience fertility problems. This could offer a way for prospective parents to have biological children that are derived from their own stem cells. It could also allow women to have babies later in life, or for women who cannot get pregnant due to cancer treatments.

More conceptually, the breakthrough suggests that human babies might someday be born from tissue samples and cell lines alone — with no direct parent involved. There are clearly a host of ethical implications that need to be addressed before any of this can be allowed to happen.

The entire study can be read in Science.

Other sources: Nature, BBC, ScienceNOW, Medical News Today.

Image: Kannanimages/shutterstock.com.

Black silicon solar cells are a relatively new technological advance that allows for the absorption of light in the infrared spectrum — about 25% of incoming sunlight. These cells are capable of pulling in an incredible 99.7% of the light that hits their surfaces, compared to traditional cells which absorb 95%. And now, owing to a breakthrough by German scientists, these cells have had their efficiency doubled.

Black silicon was developed back in the 1980s. It's a semiconductor material in which traditional silicon has been modified to have extremely low reflectivity (hence its deep black coloring), enabling it to absorb both visible and infrared light. It has many potential applications, including photodetecting for various imaging and night vision technologies.

But it can also be used for high-efficiency solar cells. Unlike traditional solar cells, black silicon is capable of pulling in sunlight on cloudy days, while also being able to draw energy from the sun at extreme angles (i.e. early and late in the day). The end result is a black panel that can produce twice the amount of electricity of regular PV panels.

And it now appears that the potential for black silicon cells has been given an extra boost. Stefan Kontermann of Fraunhofer Institute for Telecommunications has devised a new technique in which he has doubled the efficiency of these cells.

He did so by changing the manufacturing process of black silicon. Normally, infrared light lacks the energy needed to raise the electrons in the so-called 'conduction band.' But by introducing sulphur into the process, he was able to create an intermediary step in which the electrons were able to jump at the required levels, after which they can be converted into electricity. The energy levels of the sulphur was modified through the use of a laser pulse, which is used to irradiate the silicon.

The next step for the researchers are to create algorithms that will help them optimize the process and maximize efficiency.

H/t: CleanTechnica. Top image via Fraunhofer Institute for Telecommunications.

Check out this breathtaking new panoramic image that was stitched together by Stuart Atkinson from photos received by NASA just yesterday. The images were taken by the Curiosity rover which is currently romping around the Gale Crater on Mars. The misty hills in the background are unlike anything we've ever seen before — placing us right there with Curiosity on the Red Planet. Click here for the full panoramic image.

The image above was compiled by Emily Lakdawalla, who notes that the composite was put together from pictures taken by Curiosity nearly two weeks ago. It's a mosaic of three Mastcam-100 images taken on sol 51 facing southeast.

Because Curiosity is in a crater, the hills in the background are very likely the outer rim. The murkiness of the panoramas give them a kind of added realism and a total sense of presence. Thanks to Atkinson and Lakdawalla for putting these together — now we know what it's like to stand in a crater on Mars.

Images: NASA / JPL / MSSS / Stuart Atkinson & NASA / JPL / MSSS / Emily Lakdawalla.

Back in 2006, Chinese scientists released a panda named Xiang Xiang into the wild as part of their effort to increase population levels. Unfortunately, Xiang Xiang was killed a year later when he got into a fight with wild pandas. Hoping to avoid a similar setback, scientists have now released a second panda into the wild — but this time they prepared the two-year-old by putting him through a special survival school.

Named Tao Tao, the artificially bred panda was raised by his mother who fed him and taught him some basic skills (like climbing). But looking to harden the young panda and prepare him for the wild, scientists at the Wolong Nature Reserve came up with a supplemental survival training schedule.

As part of this regimen, Tao Tao's handlers wore panda suits to prevent him from getting too familiar with humans. They then exposed the panda to semi-wild conditions, including mud-rock flows, snow disasters, and rainstorms. Tao Tao also learned to fear humans and hide from them. And lastly, he was trained to recognize enemies and his own kind.

"As opposed to Xiang Xiang's captive-bred environment, Tao Tao has lived and grown in semi-wild conditions since being very little. This means that his fighting capability and survival skills both improved significantly," said project director Zhang Hemin when speaking to the Xinhua news agency.

But as the scientists admit, Tao Tao still has his work cut out for him. In addition to belligerant pandas looking to protect their food and territory, the young panda will also have to look out for bears, leopards, and wolves.

"Even though we have used new training methods, Taotao is only the second such panda released to nature, and we remain at the experimental stage," said Zhang.

Images via Reuters.

In some ways, we've become a spoiled, high-tech civilization that overlooks many of its most remarkable innovations — especially those that were developed more than 30 years ago. So, to remind us just how unappreciative we really are, here are 10 powerful technologies developed last century that are still changing the world, even though we didn't expect them to.

1. The Haber-Bosch process

Back in the early part of the 20th century, the German chemist Fritz Haber was alarmed by the growing number of mouths to feed — and the inability of farmers to keep up with the demand. Subsequently, Haber became the first person to figure out that ammonia could be created from nitrogen and hydrogen. In turn, this ammonia could be used to produce fertilizer. A lot of fertilizer. It's now estimated that Haber's insight is responsible for sustaining one-third of the Earth's population, and that half of the protein within human beings is made from the nitrogen that has become a regular part of this process. Though few people talk about it anymore, it is the most important industrial innovation developed in the 20th century. Any innovation that allows for billions of people to be adequately fed is world-changing.

2. Vaccines

Nationwide, 85,000 cases of vaccine-preventable diseases are reported every year. The recently debunked claim that there is a link between vaccines and autism hasn't helped. Globally, over 3 million people die each year mostly on account of insufficient access to vaccines. More to the point, though, it's easy to forget what it is, exactly, that we're being protected against on account of their profound effectiveness; vaccines stave off such blights as polio, diphtheria, whooping cough, measles, mumps, rubella, chickenpox, hepatitis A and B, shingles, and many other diseases. It's estimated that 3 million people are saved each year by vaccines. And just as importantly, antibiotics, which were first implemented in 1945, have likewise prevented a countless number of deaths.

3. The birth control pill

Like the use of vaccines and antibiotics, the birth control pill has become such a regular facet of modern life that we now rarely give it a second thought. But the fact of the matter is that the development of the pill in 1960 marked a major biological and sociological turning point. For the first time in our species' history, women were actually able to temporarily turn off their fertility. Moreover, its presence has irrevocably altered the social and economic landscape in those countries where it has become available. Subsequently, its impact cannot be overstated. As Claudia Goldin and others have noted, the pill is directly responsible for forging a new role for women in the economy and academia by prolonging the age at which women can choose to have children. By allowing them to invest in education and their career, it has proven to be a complete game changer.

4. Fiber Optics

The sheer ubiquity of fiber optics in our communications infrastructure, along with its presence tucked away in the background, has most certainly led to its status as an underrated technology. Though initially developed in the late 19th century, it wasn't until the 1970s that long distance attenuation could be achieved. These cables, which transmit information using bursts of light, have made them superior to conventional cables in a host of ways, including immunity to electromagnetic interference, data security, non-conductivity, no spark hazards, ease of installation, and of course, high bandwidth over long distances — including 100 terabits per second in some cases. It largely allowed the internet revolution to happen.

5. Factory farming

Also called industrial agriculture, factory farming is the technological innovation that everyone loves to hate — yet its impacts on modern society (for better or worse) are hard to dismiss. It has largely allowed human civilization to transform itself from primarily agrarian-based to city-based. As of 2007, and for the first time in our species' history, more people now live in cities than in rural areas. Because of its highly efficient, mechanized, and super-dense agricultural processes, it not longer takes legions of farmers to feed large populations. Moreover, it has resulted in more affordable food, a greater availability of labor, profitable large scale agricultural operations, and a viable export market. At the same time, however, given its toll on the environment, livestock, and human health, some consider it to be among the worst innovations of the 20th century.

6. Reflection seismology

The fact that we have technology that allows us to see what is under our feet is nothing short of remarkable. Also called seismic testing, reflection seismology is a technique that helps us determine the various characteristics and composition of underground areas by using reflected seismic waves. It essentially allows us to know what is underground before we start digging — which is a big deal to say the least. Imagine what the price of gas would be today if geologists weren't able to probe for hidden petroleum reserves. Or the precariousness of skyscrapers if contractors couldn't conduct land surveys to determine the best spot? In addition to these commercial applications, seismic testing has also proved invaluable to scientists and researchers scanning the bottom of the sea.

7. Supply chain management

Supply chain management is to the commercial sector what factory farming was to agriculture. Perfected by Wal-Mart, modern supply chain management practices have revolutionized the way companies do business — an innovation that has resulted in lower costs to consumers, and store shelves continually stocked with products. Wal-Mart was particularly effective at integrating its retail and information systems strategies to create a model that is now copied virtually everywhere. Specific strategies include the way the products are cross-docked in warehouses, and the use of sophisticated databases to record, store, and disseminate store-level information to suppliers.

8. Shipping containers

Though it might seem obvious now, the humble shipping container revolutionized the transportation industry. It's why New York and London ceased to be important ports, and why Oakland and other ports replaced them. The first batch of 58 standardized and stackable 8x8x10 boxes of corrugated metal made their way from Newark to Houston in 1956 after years of negotiations and large sums of money required to make the transition work. The idea quickly took off, resulting in the so-called containerization of the shipping industry; its introduction has since resulted in a dramatic decrease in shipping costs, an increase in efficiency, and the advent of a viable global trade market.

9. Plastic

Though Dustin Hoffman may beg to differ, a world without plastic would be a very strange and different place, indeed. Plastics are used virtually everywhere, including aeronautics, construction, electronics, packaging, and transportation. They are cheap, strong, and very light. Plastics have dramatically decreased our reliance on wood (which is not quickly renewable) and other resources, and when recycled properly, they can be reconstituted several times over. Unfortunately, however, they often end up in landfills and they are not agreeable to quick biodegradation. Today, however, we're having to deal with plastic's intense popularity — from the gigantic plastic island floating in the Pacific (which may actually be a myth), to the toxic effects of bisphenol-A.

10. Operations research and linear programming

Ops research and linear programming are two techniques that essentially allow us to make better decision and optimize systems. Operations research was developed during the Second World War to help the Allies develop such things as the convoy system to reduce shipping losses, and to provide the best strategies for fighting off German bombers. Today it's used for such things as floorplanning, scheduling, and transportation routing. Its kid brother, linear programming, is the tool that allows it to work. Itis a mathematical technique that's used to calculate the best possible solutions when allocating limited resources, whether it be energy, machines, materials, money, personnel, space, time, and so on. It's essentially used to achieve the maximum efficiency of a system or process — and at minimum costs. Put another way, it's a form of mathematically driven optimization. LP was developed in the very early parts of the 20th century by such thinkers as Leonid Kantorovich, C. Koopmans, and Andrei Nikolaevich Kolmogorov. Today it's used in such industries as planning, production, transportation, and technological development.

Images: banner: asharkyu/shutterstock, 2) Capifrutta/shutterstock, 3) Barbara J. Johnson/shutterstock, 4) Steve Collender/shutterstock, 5) Larry Rana, 6) SINC/ICM, 7) abovetopsecret, 8) QY Luong, 9) Evgenia Bolyukh/shutterstock, 10) Library and Archives Canada.

A couple of years ago, scientists working at Wake Forest Baptist confirmed that mammalian bladders are capable of a rather unique trick. Unlike other organs, the bladder can completely regenerate itself after experiencing significant tissue loss. In fact, studies on rats showed that a bladder with as much as 75% of its mass removed could repair itself after a mere eight weeks.

As amazing as this observation was, however, the scientists were confused as to how this was possible. But now, the same team of researchers think they know what's going on — and their insights could lead to organ regeneration therapies in humans similar to how amphibians and fish regenerate missing limbs.

Organ and limb regeneration is not something that's typically associated with mammals. Instead, it's the kind of thing that tends to be seen in such organisms as salamanders, starfish, and zebrafish — animals that are capable of regrowing body parts that have been lost to injury.

It's also known that mammalian livers can also repair themselves after experiencing significant tissue loss — but it's a completely different process than what's seen in limb regeneration. When a liver has its lobes removed, it undergoes a process called ‘compensatory hyperplasia' in which the remaining tissue grows to compensate for its lost size. It's more cellular regrowth than true regeneration in which a missing limb or damaged organ has its size, form, and function completely restored.

But the bladder, say the researchers, is a special organ in that it is the only one that's capable of this same kind of regeneration. And in fact, the researchers, a team led by George Christ at WFB's Institute for Regenerative Medicine, suggest that bladder regeneration in mammals has the hallmarks of both the cellular regeneration seen in the liver (robust and sequential proliferation of cell types) and that seen in limb regeneration (via blastema formation).

In the new study, which was published in PLOS ONE, the researchers showed that the rats' bodies responded to the bladder removal by increasing the rate at which certain cells divided and grew. The most significant response happened in the urothelium, the layer of tissue that lines the bladder. Then, as this activity in the bladder waned, it continued elsewhere, including the fibrous band (lamina propria) that separates the bladder lining from the bladder muscles and in the bladder muscle itself.

In other words, unlike liver "regeneration," actual functional components of the bladder were being systematically rebuilt.

The challenge for the researchers, of course, was to explain the biological mechanisms that are enabling this remarkable process to happen. One theory is that the cells in the bladder lining undergo a transformation and become a type of stem cell that works to regenerate certain parts of the bladder. Another theory is that cells in the bladder lining signal other cells to replicate, and that injury prompts stem cells to arrive through the bloodstream to repair the bladder damage.

These insights are particularly exciting in that they could yield future therapies in which other organs can be coaxed into repairing themselves in the same way — including intestines, the spinal cord — and even the heart.

Moving forward, the researchers will continue to work on identifying the exact regenerative processes by taking a look at mice. Specifically, they will breed mice who lack specific genes, allowing the researchers to explore how genes and proteins work to affect the regenerative process.

Image: vetpathologist/shutterstock.com. Inset images via Wake Forest Baptist.