The polariton laser: With 250x lower power consumption, could this be the answer to on-chip optical interconnects? | ExtremeTech

Engineers at the University of Michigan and Intel have succeeded in creating the first practical, room-temperature polariton laser. The polariton laser is of extreme interest because it requires just 0.4% of the current required by normal lasers, making it a prime candidate for use with on-chip optical interconnects. It is also believed that the polariton laser is the first new practical method of producing coherent laser light since the laser diode debuted more than 50 years ago in 1962.

In a normal laser (which is actually an acronym for “light amplification by stimulated emission of radiation”), a large amount of electrical current is applied to a lasing material. In a standard laser diode, the material is usually consists of a sandwich of semiconductor pairs (gallium arsenide and aluminium gallium arsenide are a common pairing). Electricity is pumped into this sandwich until they cross a certain threshold, at which point it emits photons (that’s the stimulated emission part). The problem is, a large amount of current is required to cross that threshold, and up until that point there’s no lasing at all.

Polariton laser diagram. A layer of gallium nitride (the lasing material) sits atop a layer of indium aluminium nitride, which prevents photons from leaking out the bottom.

A polariton laser, however, produces coherent light by stimulating polaritons — and polaritons start producing photons as soon as you pump some electrons into them, rather than being forced to cross a certain bandgap. This means that the lasing threshold is much, much lower — just 169 amperes per square centimeter, or about 250 times less than an ordinary laser. The different method of operation also means that a polariton laser can be turned on and off much faster than a conventional laser. [DOI: - "Room Temperature Electrically Injected Polariton Laser"]. In case you’re wondering, a polariton is a quasiparticle formed by an exciton (an electron and an electron hole) and a photon. The polariton entry on Wikipedia has a lot more info if you’re interested, but be warned that you’ll need a solid grasp of quantum physics to get past the first three words.

“For the past 50 years, we have relied on lasers to make coherent light and now we have something else based on a totally new principle,” says Pallab Bhattacharya, the University of Michigan engineer who led the research.

University of Michigan’s polariton laser (the triangular bit), seen under the microscope

While it’s nice to have another method of producing coherent light, by far most significant part of this discovery is the dramatically reduced power requirement. Computer designers have known for some time now that copper wires, with their high resistance and power consumption, are a significant bottleneck. There is a reason that most high-speed interconnects now use fiber-optics (laser), rather than copper wires. By far the biggest speed gains would be realized by on-chip and inter-chip optical interconnects — but so far, there hasn’t been a laser diode that’s small enough or low-power enough to enable the dream of silicon photonics. [Read: HP bets it all on The Machine, a new computer architecture based on memristors and silicon photonics.]

This polariton laser could change all that — and it’s definitely interesting that one of the paper’s authors is from Intel. Obviously we’re a long way away from integrating polariton lasers with advanced VLSI CMOS chips — IBM is much further along with that — but still, this is a very exciting breakthrough.

Top image: An IBM silicon nanophotonic chip

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Want major new aircraft designs? Wait until 2030 – CNET

Boeing and Airbus are tweaking the tried-and-true instead of going all out for all-new. Here’s why the jet-age pizzazz has been grounded.

Airbus’ A330neo is a new take on an old design. Airbus

FARNBOROUGH, UK — Over the last century, the aviation industry has steadily pushed ahead with bold new designs. But with a shift toward more incremental improvements, the airplanes of tomorrow will look a lot like the airplanes of today.

At the Farnborough International Airshow here last week, top aircraft makers Boeing and Airbus announced new passenger jets. But the difficulties of designing all-new aircraft, combined with strong airline demand, mean the two companies have begun relying more on updates to existing products rather than ground-up redesigns.

The airlines aren’t standing still, but are refitting older craft with new fuel-efficient engines, updated wings, and other improvements.

"You do not need to do a new program to develop these new technologies," Ray Conner, chief executive of Boeing Commercial Airplanes, said in an interview. "You’re able to take the things you create and bring them to other aircraft, to develop a really good airplane that meets the market needs."

The biggest example that emerged at the show was the launch of Airbus’ A330neo, named for the "new engine option" that the France-based company is bringing to the older twin-aisle jet.

"We are are looking for faster incremental improvements. This is one of the best examples we could do," said Airbus CEO Fabrice Brégier.

Also in the limelight were Airbus’ smaller A320neo, Boeing’s 737 Max, and Boeing’s bigger 777X.

Boeing and Airbus announced hundreds of new orders at the show, which is a major event on the aerospace calendar for both civilian and military aircraft.

The trend toward incremental change means that passengers hoping for a significantly better flying experience and aviation buffs excited by the latest technology should probably rein in their hopes.

A rendering of Boeing’s 777X in Emirates livery. Boeing

But shareholders can take heart: incremental improvements are a lower-risk course of action than developing all-new designs like Boeing’s 787 Dreamliner, which was supposed to arrive in 2008 but actually took until 2011.

Even with less reliance on dramatic new designs, Airbus and Boeing have huge numbers of orders to fulfill as Asian airlines boom and all airlines struggle with high fuel prices.

"There’s a seven-year backlog without even taking new orders," said Ben Moores, a senior analyst with IHS Jane’s. "You’re going to see a doubling of wide-body production over the next several years."

That’s why the industry is focusing on faster production and updates to existing designs rather than new jets that are costly to design, test, and bring to market.

"Getting a platform certified is an extremely expensive business," Moores said. "There’s not much point in designing a whole new platform when you just want to change a few bibs and bobs."

Updates big and small

Incremental improvements need not be insignificant. For example, the 777X, due in 2020, will acquire innovations that came with the 787 Dreamliner. That includes new composite wings instead of traditional aluminum designs; a tail assembly that uses new, more aerodynamic materials; bigger windows; and a more comfortable, higher interior air pressure.

Much of the 777X will be the same as the current 777, though, and many of the changes coming in future years are less significant.

"The A330 is just an engine change," Conner said. "The 787 Max is an engine change. The A320 is a new engine."

On top of that, Airbus’ attempt to bring a significant new design to market, the A350 XWB (extra-wide body) suffered a blow with one of the three planned models, the 800. At Farnborough, Brégier acknowledged that the A350-800 was effectively a flop even as he boasted that the company expects to sell more than 1,000 A330neo jets. That’s on top of more than 3,000 A320neo orders.

Airbus CEO Fabrice Brégier Stephen Shankland/CNET

Incremental updates don’t guarantee success, said Seth Kaplan, managing partner of Aviation Weekly. Boeing’s 747-8, an update to its iconic but decades-old 747 design, "has been such a slow seller that perhaps Boeing shouldn’t even have bothered," he said.

But flops are less painful with upgrades than with all-new designs such as Airbus’ even bigger rival to the 747, the 550-passenger double-decker A380. The A380 hasn’t done as badly in the marketplace as the 747, "but this is less of a problem for Boeing than the A380 is for Airbus because…the 747-8 was a far lower-risk proposition."

High fuel costs mean new engines

A major incentive for updates is better fuel efficiency — in particular fuel efficiency per passenger. Fuel efficiency is a huge constraint, with oil prices high and not expected to drop, Moores said.

The A330neo is 14 percent more fuel-efficient than the A330ceo (current engine option), mostly because of its new engines but also because it squeezes 10 more seats by reconfiguring lavatories and crew galley areas. The 737 Max 8 gets a 20 percent fuel-efficiency boost through new engines and 11 more seats.

Since Boeing introduced the current 737NG (next generation) in 1997, the company has improved its fuel efficiency by 6 percent. The 737 Max will improve it another 20 percent over that, and each percentage point is worth about $600,000 in savings over the life of the plane, said Randy Tinseth, vice president of marketing for Boeing’s commercial airplane division.

Airbus has its own arguments prepared, though. The new engines, passenger accommodation, and wing aerodynamics on the A330neo mean that "we achieve the equivalent [fuel consumption] of the 787-8," Brégier said. And the A330neo benefits from the A330’s proven reliability, pilot certifications, and other incumbent advantages.

Boeing’s extra-long 787-9 loops over Farnborough (pictures)See full gallery


Next big steps

Innovation is certainly not dead — it will just be a long time before the next big bang arrives beyond the 787 Dreamliner and A350 XWB.

Boeing’s 787-9 takes off at the Farnborough International Airshow. Stephen Shankland/CNET

The cycle time for big redesigns "used to be every 10 years. It takes that kind of time to develop new engines and new airframe technology," Conner said. But now it looks like it will be closer to 20 years, Moores said, when aircraft manufacturers choose to save significant weight by replacing today’s hydraulic controls with electrical controls for plane wings and other control surfaces.

"They’ll start looking at all-electric aircraft in the 2020s for production in the first half of the 2030s," Moores said.

Airbus thinks electric and hybrid-electric aircraft have a future, but absent major improvements in battery technology, that won’t extend to larger aircraft that carry the vast majority of passengers.

The long wait for major conventional jet improvements could give Boeing an advantage because the 787 is a more radical redesign than the A350 XWB. The 787 uses lots of composite materials like carbon fiber for its wings and fuselage, but the A350 sticks with traditional aluminum. "It’s a lot lower risk," Moores said, and it’ll still sell well, but Boeing CEO Jim McNerney said at the show the 787’s new technology gives Boeing a "capability and performance advantage for the next or 20 or 30 years."

At Farnborough, Airbus’ lightest and heaviest planes (pictures)See full gallery


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By 2025, Self-Driving Trucks Will Be Cruising Down Our Highways | Co.Exist | ideas + impact

The truck drivers of the future may not drive much at all.

A new self-driving truck from Daimler takes care of pretty much everything on the highway, so after pulling onto the road and pushing a button, a driver can swivel away from the steering wheel, turn on a tablet, and work on something else.

Not only is the system less stressful and more interesting for the driver–who otherwise might spend 10 or 11 hours on a monotonous journey that demands constant attention–it virtually eliminates the possibility of accidents.

“In the future, accidents caused by human error will therefore be substantially a thing of the past,” Daimler writes in a statement.

“Machines make fewer mistakes than people, their attention never lapses, and they do not react emotionally or depending on mood and fitness level.”

A network of cameras and sensors around the truck identify lane markings, recognize pedestrians and other vehicles, and can even read traffic signs.

As other self-driving cars and trucks join the road, they’ll be able to communicate automatically back and forth, so traffic flows at the optimum speed–helping ease traffic jams and save a substantial amount of fuel.

In Germany, where Daimler is based, the number of trucks on the road has grown by 80% over the last two decades, and in the EU overall, truck transport may double again by 2050.

The new trucks are designed to help ease the pain of that traffic, and possibly attract more drivers to a job that isn’t currently seen as prestigious.

"Drivers will no longer be ‘truckers,’ but rather ‘transport managers’ in an attractive mobile workplace offering scope for new professional skills," Daimler writes.

The new truck, called Mercedes-Benz Future Truck 2025, was recently tested on a stretch of the Autobahn, disguised in a black-and-white foil wrapper that hid its shape from others on the road.

There are legal and political issues to sort out before it can be in use; if people are afraid of self-driving cars, it’s likely they might be even more resistant to the idea of 80,000 pound trucks barreling down the road with no one at the wheel.

Still, Daimler expects it will be in use in a decade, and on the technical side, it could be ready to go in as little as five years.

"This short time period means this: Truck drivers currently aged around 50 will become familiar with autonomous driving during their professional lives," Daimler writes. "For all younger drivers it will one day become a day-to-day part of professional life."

The truck drivers of the future may not drive much at all.

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What’s behind your blood type? | Ars Technica

After over a century of study, we’re still not entirely sure.

by Carl Zimmer/Mosaic July 15 2014, 8:00am CDT

When my parents informed me that my blood type was A+, I felt a strange sense of pride. If A+ was a top grade in school, then surely A+ must also be the most excellent of blood types—a biological mark of distinction.

It didn’t take long for me recognize just how silly that feeling was, but I didn’t learn much more about what it really meant to have A+. By the time I was an adult, all I really knew was that if I should end up in a hospital in need of blood, the doctors there would need to make sure they transfused me with a suitable type.

And yet there remained some nagging questions. Why do 40 percent of Caucasians have Type A, while only 27 percent of Asians do? Where do different blood types come from, and what do they do?

To get some answers, I went to the experts—to hematologists, geneticists, evolutionary biologists, virologists, and nutrition scientists. In 1900, the Austrian physician Karl Landsteiner first discovered blood types, winning the Nobel Prize for his research in 1930. Since then, scientists have developed ever more powerful tools for probing the biology of blood types. They’ve found some intriguing clues about blood types—tracing their deep ancestry, for example, and detecting influences of blood types on our health. And yet I found that in many ways, blood types remain strangely mysterious. Scientists have yet to come up with a good explanation for their very existence.

“Isn’t it amazing?” says Ajit Varki, a biologist at the University of California at San Diego, “Almost a hundred years after the Nobel Prize was awarded for this discovery, we still don’t know exactly what they’re for."

Much safer transfer of blood than what happened during early experimentation.

American Red Cross Oregon Trail chapter

The first transfusions

My knowledge that I’m Type A comes to me thanks to one of the greatest discoveries in the history of medicine. Because doctors are aware of blood types, they can save lives by transfusing blood into patients. But for most of history, the notion of putting blood from one person into another was a feverish dream.

Renaissance doctors mused about what would happen if they put blood into the veins of their patients. Some thought that it could be a treatment for all manner of ailments, even insanity. Finally, in the 1600s, a few doctors tested out the idea, with disastrous results. A French doctor injected calf’s blood into a madman, who promptly started to sweat and vomit and produce urine the color of chimney soot. After another transfusion, the man died.

Such calamities put transfusions into disrepute for 150 years. Even as recently as the nineteenth century, only a few doctors dared try out the procedure. One of them was a British physician named James Blundell. Like other physicians of his day, he watched many of his female patients die from bleeding during childbirth. After the death of one patient in 1817, he found he couldn’t resign himself to the way things were.

“I could not forbear considering, that the patient might very probably have been saved by transfusion,” he later wrote.

Blundell became convinced that the earlier disasters with blood transfusions came about thanks to one fundamental error: “it transfuses the blood of the brute,” as he put it. Doctors shouldn’t transfer blood between species, he concluded. As he wrote, “The different kinds of blood differ very importantly from each other.”

Human patients should only get human blood, Blundell decided. But no one had ever tried to perform such a transfusion. Blundell set about doing so by designing a system of funnels and syringes and tubes that could channel blood from a donor to an ailing patient. After testing the apparatus out on dogs, Blundell was summoned to the bed of a man who was bleeding to death. “Transfusion alone could give him a chance of life,” Blundell wrote.

Several donors provided Blundell with 14 ounces of blood, which he injected into the man’s arm. After the procedure, the patient told Blundell that he felt better—“less fainty” as he put it—but two days later, he died.

Still, the experience convinced Blundell that blood transfusion would be a huge benefit to mankind, and he continued to pour blood into desperate patients in the years to come. All told, he performed 10 blood transfusions. Only four patients survived.

While some other doctors experimented in blood transfusion in the 1800s, their success rates were also dismal. Various approaches were tried, including attempts in the 1870s to use milk for transfusion (which were, unsurprisingly, fruitless and dangerous).

Listing image by Flickr user: Chris Gladis

Finding your type

Blundell was correct in believing that humans should only get human blood. But he didn’t know another crucial fact about blood: that humans should only get blood from certain other humans. It’s likely that Blundell’s ignorance of this simple fact led to the deaths of some of his patients. What makes those deaths all the more tragic is the discovery of blood types a few decades later and that determining blood types is a fairly simple procedure.

The first clues to why the transfusions of the early nineteenth century had failed were clumps of blood. When scientists in the late 1800s mixed blood from different people in test tubes, they noticed that sometimes the red blood cells stuck together. Because the blood generally came from sick patients, scientists dismissed the clumping as some sort of pathology not worth investigating. Nobody bothered to see if the blood of healthy people clumped until Karl Landsteiner wondered what would happen. Immediately, he could see that mixtures of healthy blood sometime clumped, too.


The Nobel Foundation
Landsteiner set out to map the clumping pattern, collecting blood from members of his lab, including himself. He separated each sample into red blood cells and plasma, and then he combined plasma from one person with cells from another.

Landsteiner found that the clumping occurred only if he mixed certain people’s blood together. By working through all the combinations, he sorted his subjects into three groups. He gave them the entirely arbitrary names of A, B, and C. (Later on C was renamed O, and a few years later, other researchers discovered the AB group. In the mid-1900s, the American researcher Philip Levine discovered another way to categorize blood based on whether it had the Rhesus blood factor. The plus sign at the end of Landsteiner’s letters indicates whether a person has the factor or not.)

When Landsteiner mixed the blood from different people together, he discovered it followed certain rules. If he mixed the plasma from group A with red blood cells from someone else in group A, the plasma and cells remained a liquid. The same rule applied to the plasma and red blood cells from group B. But if Landsteiner mixed plasma from group A with red blood cells from B, the cells clumped (and vice versa).

The blood from people in group O was different. When Landsteiner mixed either A and B red blood cells with O plasma, the cells clumped. But he could add A or B plasma to O red blood cells without any clumping.

It’s this clumping that makes blood transfusions so potentially dangerous. If a doctor accidentally injected type B blood into my arm, my body would become loaded with tiny clots. They would disrupt my circulation, causing me to start bleeding massively, struggle for breath, and potentially die. But if I received either type A or type O blood, I would be fine.

Landsteiner didn’t know what precisely distinguished one blood type from another. Later generations of scientists discovered that the red blood cells in each type are decorated with different molecules on their surface. In my type A blood, for example, the cells build these molecules in two stages, like two floors of a house. The first floor is called an H antigen. On top of the first floor, the cells build a second, called the A antigen.

People with type B blood, on the other hand, build a second floor to the house that has a different shape. And people with type O build a single-story ranch house: they only build the H antigen and go no further.

Each person’s immune system becomes familiar with his or her own blood type. If people receive a transfusion with the wrong blood type, however, their immune system responds with a furious attack, as if the blood was an invader. The exception to this rule is Type O blood. It only has H antigens, which are present in the other blood types. To a person with type A or type B, it seems familiar. That familiarity makes people with type O blood universal donors, and their blood especially valuable to blood centers.

Landsteinerreported his experiment in a short, terse paper in 1900. “It might be mentioned that the reported observations may assist in the explanation of various consequences of therapeutic blood transfusions,” he concluded with exquisite understatement. Within a few years, Landsteiner’s discovery opened the way to safe, large-scale blood transfusions. And even today, blood banks use Landsteiner’s basic method of clumping blood cells as a quick, reliable test for blood types.

But even as Landsteiner answered an old question, he raised new ones. What, if anything, were blood types for? Why should red blood cells bother with building their molecular houses? And why do people have different houses?

Solid scientific answers to these questions have been hard to come by. And in the meantime, some unscientific explanations have gained huge popularity. “It’s just been ridiculous,” sighs Connie Westhoff, the Director of Immunohematology and Genomics at the New York Blood Center. For Westhoff and many experts on blood types, there’s nothing more ridiculous than the hugely popular “Blood Type Diet."

V is for vegetable, which is good for A?

Flickr user: Sonny Abesamis

Popular pseudoscience

In 1996, a naturopath named Peter D’Adamo published a book called Eat Right 4 Your Blood Type. D’Adamo argued that we must eat according to our blood type in order to harmonize with our evolutionary heritage.

Blood types, he claimed, “appear to have arrived at critical junctures of human development.” According to D’Adamo, Type O arose in our hunter-gatherer ancestors in Africa, Type A blood at the dawn of agriculture, and Type B developed between 10,000 and 15,000 years ago in the Himalayan highlands. Type AB, he argued, is a modern blending of A and B.

From these suppositions, D’Adamo then claimed that our blood type determines what food we should eat. With my agriculture-based Type A blood, for example, I should be a vegetarian. People with the ancient hunter Type O should have a meat-rich diet and avoid grains and dairy. Foods that weren’t suited to our blood type contained antigens that could cause all sorts of illness. D’Adamo recommended his diet as a way to reduce infections, lose weight, fight cancer and diabetes, and slow the aging process.

D’Adamo’s book has sold seven million copies and has been translated into 60 languages. It’s been followed by a string of other blood-type diet books; D’Adamo also sells a line of blood-type-tailored diet supplements on his website. As a result, doctors often get asked by their patients if blood-type diets actually work.

The best way to answer that question is to run an experiment. In Eat Right 4 Your Blood Type, D’Adamo wrote that he was in the eighth year of a decade-long trial of blood-type diets on women with cancer. But 18 years later, there’s no trace of such a trial in the published scientific literature.

Recently, researchers at the Red Cross in Belgium decided to see if there was any other evidence in its favor. They hunted through the scientific literature for experiments that measured the benefits of diets based on blood types. Although they examined more than 1,000 studies, their efforts were futile. “There is no direct evidence supporting the health effects of the ABO blood type diet,” says Emmy DeBuck of the Belgian Red Cross-Flanders.

After DeBuck and her colleagues published their review in the American Journal of Clinical Nutrition, D’Adamo responded on his blog. He waved away the importance of trials, instead asserting that basic biological research shows that his blood-type diet is right. “There is good science behind the blood type diets, just like there was good science behind Einstein’s mathmatical [sic] calculations that led to the Theory of Relativity,” he wrote.

Comparisons to Einstein notwithstanding, the scientists who actually do research on blood types categorically reject such a claim. “The promotion of these diets is wrong,” a group of researchers flatly declared in Transfusion Medicine Review.

Although, some people who follow the Blood Type Diet see positive results, according to Ahmed El-Sohemy, a nutrition scientist at the University of Toronto, that’s no reason to think that blood types have anything to do with the diet’s success.

El-Sohemy is an expert in the emerging field of nutrigenomics. He and his colleagues have brought together 1,500 volunteers to track the foods they eat and their health. They are analyzing the DNA of their subjects to see how their genes may influence how food affects them. Two people may respond very differently to the same diet based on their genes.

“Almost every time I give talks about this, someone at the end asks me, ‘Oh, is this like the blood type diet?’” El-Sohemy says. As a scientist, El-Sohemy found Eat Right 4 Your Blood Type lacking. “None of the stuff in the book is backed by science,” he said. But El-Sohemy realized that, since he knew the blood type of his 1,500 volunteers, he could see if the Blood Type Diet actually did people any good.

El-Sohemy and his colleagues divided up their subjects by their diets. Some ate meat-based diets D’Adamo recommended for Type O, some ate a mostly vegetarian diet recommended for Type A, and so on. The scientists gave each person in the study a score for how well they adhered to each Blood Type diet.

The researchers did find, in fact, that some of the diets could do people some good. People who stuck to the Type A diet, for example, had a lower body-to-mass index, smaller waists, and lower blood pressure. People on the Type O diet had lower triglycerides. The Type B diet—rich in dairy products—provided no benefits.

“The catch,” says El-Sohemy, “is that it has nothing to do with people’s blood type.” In other words, if you have Type O blood, you can still benefit from a so-called Type A diet just as much as someone with Type A blood—probably because the benefits of a mostly vegetarian diet can be enjoyed by anyone. Anyone on a Type O diet cuts out lots of carbohydrates, with the attending benefits for virtually everyone. Likewise, a diet rich in dairy products isn’t healthy for anyone—no matter their blood type.

Enlarge Another animal with A and B variants? Did you guess gibbons?
Flickr user: Tambako

My type of gibbon

One of the appeals of the Blood Type Diet is that it comes with an origins story that explains how we got our different blood types. But that story bears little resemblance to the evidence that scientists have gathered about their evolution.

After Landsteiner’s discovery of human blood types in 1900, other scientists wondered if the blood of other animals came in different types, too. It turned out that some primate species had blood that mixed nicely with certain human blood types. But for a long time it was hard to know what to make of the findings. The fact that a monkey’s blood doesn’t clump with my type A blood doesn’t necessarily mean that the monkey inherited the same type A gene that I carry from a common ancestor we share. Type A blood might have evolved more than once.

The uncertainty slowly began to dissolve starting in the 1990s, as scientists deciphered the molecular biology of blood types. They found that a single gene, called ABO, is responsible for building the second floor of the blood type house. The A version of the gene differs by a few key mutations from B. People with type O blood have mutations in the ABO gene that prevent them from making the enzyme that would build either the A or B antigen.

Scientists could then begin comparing the ABO gene from humans to other species.

Laure Segurel of the National Center for Scientific Research in Paris and her colleagues have led the most ambitious survey of ABO genes in primates to date. And they’ve found that our blood types are profoundly old. Gibbons and humans both have variants for both A and B blood types, and those variants come from a common ancestor that lived 20 million years ago.

Our blood types might be even older, but it’s hard to know how old. Scientists have yet to analyze the genes of all primates, and so they can’t see how widespread our own versions are among other species. But the evidence that scientists have gathered so far already reveals a turbulent history to blood types. In some lineages, mutations have shut down one blood type or another. Chimpanzees, our closest living relatives, only have type A and type O blood. Gorillas, on the other hand, only have B. In some cases, mutations have altered the ABO gene, turning type A blood into type B.

Even in humans, scientists are finding mutations have repeatedly arisen that prevent the ABO protein from building a second story on the blood type house. These mutations have turned blood types from A or B to O. “There are hundreds of ways of being type O,” says Westhoff.

Unexpected benefits

Being Type A is not a legacy of my proto-farmer ancestors, in other words. It’s a legacy of my monkey-like ancestors. Surely, if my blood type has endured for millions of years, it must be providing me with some obvious biological benefit. Otherwise, why do my blood cells bother building such complicated molecular structures?

Yet scientists have struggled to identify what benefit the ABO gene provides. “There is no good and definite explanation for ABO,” says Antoine Blancher of the University of Toulouse, “although many answers have been given.”

The most striking demonstration of our ignorance about the benefit of blood types came to light in Bombay in 1952. Doctors discovered that a handful of patients had no ABO blood type at all—not A, not B, not AB, not O. If A and B are two-story buildings, and O is a one-story ranch house, then these Bombay patients had only an empty lot.

Since its discovery, this condition—called the Bombay phenotype—has turned up in other people, although it remains exceedingly rare. And as far as scientists can tell, there’s no harm that comes from the Bombay phenotype. The only known medical risk it presents comes when it’s time for a blood transfusion. They can only accept blood from other people with the same conditions. Even blood type O, supposedly the universal blood type, can kill them.

The Bombay phenotype proves that there’s no immediate life-or-death advantage to having ABO blood types. Some scientists think that the explanation for blood types may lie in their variation. That’s because different blood types may protect us from different diseases.

Doctors first began to notice a link between blood types and specific diseases in the mid-1900s, and the list has continued to grow. “There are still many associations being found between blood groups and infections, cancers, and a range of diseases,” Pamela Greenwell of the University of Westminster told me.

From Greenwell, I learned to my displeasure that blood type A puts me at a higher risk of several types of cancer, such as some forms of pancreatic cancer and leukemia. I’m also more prone to smallpox infections, heart disease, and severe malaria. On the other hand, people with other blood types have to face increased risks of other disorders. People with Type O, for example, are more likely to get ulcers and ruptured Achilles tendons.

These links from blood types to diseases have a mysterious arbitrariness about them, and scientists have only begun to work out the reasons behind some of them. For example, Kevin Kain of the University of Toronto and his colleagues have been investigating why people with Type O are better protected against severe malaria than other blood types. His studies indicate that immune cells have an easier job of recognizing infected blood cells if they’re Type O than other blood types.

More puzzling are the links between blood type and diseases that have nothing to do with the blood. Take norovirus. This nasty pathogen is the bane of cruise ships, because it can rage through hundreds of passengers, causing violent vomiting and diarrhea. It does so by invading cells lining the intestines, leaving blood cells untouched. Nevertheless, people’s blood type influences the risk that they will be infected by a particular strain of norovirus.

The solution to this particular mystery can be found in the fact that blood cells are not the only cells to produce blood type antigens. They are also produced by cells in blood vessel walls, the airway, skin, and hair. Many people even secrete blood type antigens in their saliva. Noroviruses make us sick by grabbing on to the blood type antigens produced by cells in the gut.

Yet a norovirus can only grab firmly onto a cell if its proteins fit snugly onto a blood type antigen. So it’s possible that each strain of norovirus has proteins that are adapted to attach tightly to certain blood type antigens, but not others. That would explain why our blood type can influence which norovirus strains can make us sick.

It may also be a clue as to why a variety of blood types have endured for millions of years. Our primate ancestors were locked in a never-ending cage match with countless pathogens, including viruses, bacteria, and other enemies. Some of those pathogens may have adapted to exploit different kinds of blood type antigens. The pathogens that were best suited to the most common blood type would have fared best, because they had the most hosts to infect. But, gradually, they may have destroyed that advantage by killing off their hosts. Meanwhile, primates with rarer blood types would have thrived, thanks to their protection against some of their enemies.

As I contemplate this possibility, my Type A blood remains as puzzling to me as when I was a boy. But it’s a deeper state of puzzlement that brings some pleasure—I realize that the reason for my blood type may ultimately have nothing to do with blood at all.

This article originally appeared at Mosaic.

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Long Tail Feathers Adorned Four-Winged Dinosaur

A raptor dinosaur from China sported four wings and a long tail, researchers report.

A fossil of a four-winged raptor helps us understand how dinosaurs evolved to take advantage of feathers in the era of the earliest birds.

Photograph by Luis Chiappe

Dan Vergano

National Geographic

Published July 15, 2014

In the process of adapting to flight, feathered dinosaurs also evolved a way to land safely, suggests a 125-million-year-old four-winged flier from China. A surprisingly long feathered tail on the ancient creature, scientists reported on Tuesday, served as a landing brake.

Discovery of the feathered dinosaur, dubbed Changyuraptor yangi ("great feather" in Chinese), adds to the roster of feathered raptor dinosaurs with hind wings found in northeastern China in the past two decades. It is the biggest one found so far, and the fifth such species. (Related: "Dinosaur-Era Fossil Shows Birds’ Feathers Evolved Before Flight.")

The finds add to our understanding of how dinosaurs evolved to take advantage of feathers in the era of the earliest birds. Weighing about nine pounds (four kilograms) and measuring four feet (1.2 meters) long, Changyuraptor (JHONG-YU-rapp-tor) likely swooped down on early birds and mammals, researchers report in the journal Nature Communications.

"An animal that size that came down flying has to slow down or else crash," says study co-author Luis Chiappe of the Natural History Museum of Los Angeles County. "They could adjust the tail to change their pitch as they landed."

Fabled Fossils

The fossil was originally collected by farmers in China’s Liaoning Province, famous for its preservation of dinosaur, insect, and early mammal remains from more than a hundred million years ago. Its most striking feature is the imprint of long feathers that once covered the bird. The dinosaur’s tail feathers were a foot long, one-fourth the size of the creature overall. Proportionally, that is far longer than tail feathers on modern birds, Chiappe says.

By highlighting the extremes of early feathered dinosaur anatomy, Changyuraptor helps scholars better understand the origin and early evolution of flight in dinosaurs, says ancient feather expert Ashley Heers of the University of London. An aerodynamic analysis in the study shows that Changyuraptor should have been able to brake in flight by altering the pitch of the tail as it plummeted earthward.

The ability to control airborne trajectories determines the success of flying predators today, Heers notes by email, "and likely played an important role during the origins of flight as well."

Before the piece was purchased for study by Chinese researchers at Bohai University, in Jinzhou, someone had attempted to artificially reconstruct the neck of the almost complete fossil. "None of the rest of the fossil has any alteration," Chiappe says.

Winged Victory

Changyuraptor likely swooped down upon small birds, fish, or early mammals living in the forests of the era. But whether the four-winged dinosaurs were true wing-flapping fliers or merely gliders remains an open question, Chiappe says. "I think they could fly myself," he says. (Related: "A Velociraptor Without Feathers Isn’t a Velociraptor.")

Paleontologist Gareth Dyke of the United Kingdom’s University of Southampton sees the creature as more of a glider. "Feathers had a lot more uses than flying, we know from lots of feathered dinosaurs."

Follow Dan Vergano on Twitter.

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The Brilliant Machine That Could Finally Fix Airport Security | Autopia | WIRED

Fans at a World Cup game at Arena de Baixada stadium in Curitiba, Brazil use the Qylatron to go through security. Qylur

Australian fans pumped to see their team take on Spain during the first round of the World Cup were intrigued by the honeycomb-like machine that had replaced the standard manual search process at Arena de Baixada stadium in Curitiba, Brazil. They were less thrilled when the machine spotted the toy kangaroos they were trying to sneak into the match.

That machine is the Qylatron Entry Experience Solution, and it could soon replace a crappy experience of going through security checks at airports and other venues with one that’s faster and less invasive. Instead of having a human poke around in your bag, the machine scans it for a variety of threats in just a few seconds. Searching those Aussies and other soccer fans may prove to be a watershed moment for the system, a successful test of how well it can spot trouble and move people through security, efficiently and with their dignity intact.

The system is the work of Silicon Valley-based Qylur Security Systems, and it consists of five pods that sit around a central sensor. The process is a much closer to being pleasant than having your stuff searched by hand at a stadium or going through the mundane horrors of TSA security. You don’t have to open your bag or let any else touch it. And with five people moving through at once, you’re through security before you have time to really get annoyed.

The whole process is simple. You hold your ticket up to the machine, and it assigns you a pod, in which you place your bag in. Each pod is about the size of a big microwave, so will fit most bags, but maybe not the biggest carry-ons you can take on a plane (though Qylur presumably could tweak the size). Close the door and walk around to the other side. In the time it takes you to get over there, the machine scans the bag for a range of threats. Qylur isn’t keen on explaining how the technology works, but we know it has radiation and chemical sensors to pick out explosives. With a multi-view X-ray, it matches the shapes of objects it sees against a large, pre-programmed library of images to pick out prohibited items like guns and knives. If it sees a threat, it alerts a security officer, and the door of the pod turns red. If not, the door turns green, and you unlock it with your ticket. Take your bag and go.

Before Qylur can lock down contracts to move into airports and other venues, it has to prove the system works. So it went to Brazil, where it was hired by an event operations company running some World Cup games. Qylur was given responsibility for one entrance to Arena de Baixada stadium, for four games.

The system is made to look for guns and bombs, but the World Cup presented an unusual challenge. FIFA is really picky about what fans can bring into the stadium. On top of weapons, the banned item list covers long umbrellas, flagpoles, banners or flags bigger than 2 meters by 1.5 meters, megaphones, vuvuzelas (great call), computers, and a list of of otherwise mundane things, including those kangaroos the Aussies love, and large quantities of flour.

Teaching the Qylatron to spot those things the way it sees guns and knives would have involved adding images of them to the machine’s database. Instead, the team worked in what CEO Dr. Lisa Dolev calls collaboration mode. The machine scans for conventional threats like weapons on its own, and a human operator in a remote room scans the images to pick out those illicit flags, bags of flour, and yes, toy kangaroos. The operator watches the images from all five of the machine’s pods at once, which Dolev says isn’t a problem (no word on if she’s hired Rain Man). He alerts an employee at the machine if he spots something suspicious. Man and machine “ended up stopping an awful lot of bags,” Dolev says, but the fans seemed to like the process anyway.

The company plans to deploy its technology at a few more venues this year. It will soon shift to more permanent setups, Dolev says, though she won’t reveal specific spots just yet. We assume TSA isn’t on the list of clients—getting the agency to change its ways takes a lot of work—but hopefully Qylur can find its way into our airports sometime soon.

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Do People Only Use 10 Percent of Their Brains? – Scientific American

What’s the matter with only exploiting a portion of our gray matter?
Feb 7, 2008 By Robynne Boyd

Oleg Prikhodko/iStockPhoto

The human brain is complex. Along with performing millions of mundane acts, it composes concertos, issues manifestos and comes up with elegant solutions to equations. It’s the wellspring of all human feelings, behaviors, experiences as well as the repository of memory and self-awareness. So it’s no surprise that the brain remains a mystery unto itself.

Adding to that mystery is the contention that humans "only" employ 10 percent of their brain. If only regular folk could tap that other 90 percent, they too could become savants who remember π to the twenty-thousandth decimal place or perhaps even have telekinetic powers.

Though an alluring idea, the "10 percent myth" is so wrong it is almost laughable, says neurologist Barry Gordon at Johns Hopkins School of Medicine in Baltimore. Although there’s no definitive culprit to pin the blame on for starting this legend, the notion has been linked to the American psychologist and author William James, who argued in The Energies of Men that "We are making use of only a small part of our possible mental and physical resources." It’s also been associated with Albert Einstein, who supposedly used it to explain his cosmic towering intellect.

The myth’s durability, Gordon says, stems from people’s conceptions about their own brains: they see their own shortcomings as evidence of the existence of untapped gray matter. This is a false assumption. What is correct, however, is that at certain moments in anyone’s life, such as when we are simply at rest and thinking, we may be using only 10 percent of our brains.

"It turns out though, that we use virtually every part of the brain, and that [most of] the brain is active almost all the time," Gordon adds. "Let’s put it this way: the brain represents three percent of the body’s weight and uses 20 percent of the body’s energy."

The average human brain weighs about three pounds and comprises the hefty cerebrum, which is the largest portion and performs all higher cognitive functions; the cerebellum, responsible for motor functions, such as the coordination of movement and balance; and the brain stem, dedicated to involuntary functions like breathing. The majority of the energy consumed by the brain powers the rapid firing of millions of neurons communicating with each other. Scientists think it is such neuronal firing and connecting that gives rise to all of the brain’s higher functions. The rest of its energy is used for controlling other activities—both unconscious activities, such as heart rate, and conscious ones, such as driving a car.

Although it’s true that at any given moment all of the brain’s regions are not concurrently firing, brain researchers using imaging technology have shown that, like the body’s muscles, most are continually active over a 24-hour period. "Evidence would show over a day you use 100 percent of the brain," says John Henley, a neurologist at the Mayo Clinic in Rochester, Minn. Even in sleep, areas such as the frontal cortex, which controls things like higher level thinking and self-awareness, or the somatosensory areas, which help people sense their surroundings, are active, Henley explains.

Take the simple act of pouring coffee in the morning: In walking toward the coffeepot, reaching for it, pouring the brew into the mug, even leaving extra room for cream, the occipital and parietal lobes, motor sensory and sensory motor cortices, basal ganglia, cerebellum and frontal lobes all activate. A lightning storm of neuronal activity occurs almost across the entire brain in the time span of a few seconds.

"This isn’t to say that if the brain were damaged that you wouldn’t be able to perform daily duties," Henley continues. "There are people who have injured their brains or had parts of it removed who still live fairly normal lives, but that is because the brain has a way of compensating and making sure that what’s left takes over the activity."

Being able to map the brain’s various regions and functions is part and parcel of understanding the possible side effects should a given region begin to fail. Experts know that neurons that perform similar functions tend to cluster together. For example, neurons that control the thumb’s movement are arranged next to those that control the forefinger. Thus, when undertaking brain surgery, neurosurgeons carefully avoid neural clusters related to vision, hearing and movement, enabling the brain to retain as many of its functions as possible.

What’s not understood is how clusters of neurons from the diverse regions of the brain collaborate to form consciousness. So far, there’s no evidence that there is one site for consciousness, which leads experts to believe that it is truly a collective neural effort. Another mystery hidden within our crinkled cortices is that out of all the brain’s cells, only 10 percent are neurons; the other 90 percent are glial cells, which encapsulate and support neurons, but whose function remains largely unknown. Ultimately, it’s not that we use 10 percent of our brains, merely that we only understand about 10 percent of how it functions.

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