science

Engineering the $325,000 Burger

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The idea of creating meat in a laboratory — actual animal tissue, not a substitute made from soybeans or other protein sources — has been around for decades. The arguments in favor of it are many, covering both animal welfare and environmental issues. But now Dr. Mark Post, an engineer in the Netherlands, wants to show the world that meat made in the laboratory may be a reality, thanks to a $325,000 burger his lab finally developed (the unveiling has been delayed):

Dr. Post, one of a handful of researchers in the field, has made strides in developing cultured meat through the use of stem cells — precursor cells that can turn into others that are specific to muscle — and techniques adapted from medical research for growing tissues and organs, a field known as tissue engineering. (Indeed, Dr. Post, a physician, considers himself first and foremost a tissue engineer, and about four-fifths of his time is dedicated to studying how to build blood vessels.)

Yet growing meat in the laboratory has proved difficult and devilishly expensive. Dr. Post, who knows as much about the subject as anybody, has repeatedly postponed the hamburger cook-off, which was originally expected to take place in November. His burger consists of about 20,000 thin strips of cultured muscle tissue. Dr. Post, who has conducted some informal taste tests, said that even without any fat, the tissue “tastes reasonably good.” For the London event he plans to add only salt and pepper.

What kind of cells are used in creating this cultured meat?

In his work on cultured meat, Dr. Post uses a type of stem cell called a myosatellite cell, which the body itself uses to repair injured muscle tissue. The cells, which are found in a certain part of muscle tissue, are removed from the cow neck and put in containers with the growth medium. Through much trial and error, the researchers have learned how best to get the cells to grow and divide, doubling repeatedly over about three weeks.

The cells are then poured onto a small dab of gel in a plastic dish. The nutrients in the growth medium are greatly reduced, essentially starving the cells, which forces them to differentiate into muscle cells. “We use the cell’s natural tendency to differentiate,” Dr. Post said. “We don’t do any magic.”

My guess? We are about ten to fifteen years away where cultured meat becomes mainstream.

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Previously: the quarter million pounder with cheese.

Will Humans Ever Encounter Aliens?

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This is a thought-provoking analysis by Paul Tyma on why the human race will never encounter aliens:

So why else might they [aliens] want to come here? Maybe they want to trade with us. Well, yeah, right. If you’ve gotten this far it’s obvious we have no tech that would interest them. Maybe we’d be able to trade them some local arts and crafts or pottery or something – but other than that, they won’t be interested in our childish technology.

Well, maybe they want to study us? Well, maybe. It seems probable that if they were on a mission to study life forms, we would not be the first planet they would have visited. Chances are, they’ve seen other life forms already. Probably some at least similar to us. Statistically speaking, we might be interesting but not all that interesting.

What do you think?

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(Via Tim O’Reilly)

What Causes Fairy Circles in the Namib Desert?

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A fascinating new paper in Science on the so-called “fairy circles” in the inhospitable Namib Desert in southern Africa:

The sand termite Psammotermes allocerus generates local ecosystems, so-called fairy circles, through removal of short-lived vegetation that appears after rain, leaving circular barren patches. Because of rapid percolation and lack of evapotranspiration, water is retained within the circles. This process results in the formation of rings of perennial vegetation that facilitate termite survival and locally increase biodiversity. This termite-generated ecosystem persists through prolonged droughts lasting many decades.

Ars Technica summarizes:

But now, after a six-year study and more than 40 trips to the Namib Desert, Dr. Norbert Juergens believes he has come to understand the biological underpinnings of this strange phenomenon. According to Juergens, a single species of termites is responsible for creating and maintaining the circles. But the barren circles aren’t just a byproduct of these tiny insects living below the sandy desert surface; they are part of a carefully cultivated landscape that helps the termites—and many other organisms—thrive in an otherwise inhospitable climate.

Juergens hypothesized that if the fairy circles’ cause was biological, the organism would need to co-occur with the circles and would probably not be found elsewhere. Only one species fit the bill:Psammotermes allocerus, the sand termite. Not only was the sand termite the only insect species that lived across the entire range of the fairy circles, but these termites were found to be living beneath nearly every circle sampled. And the harder the termites worked – foraging, burrowing, and dumping their refuse – the more grass died, leading Juergens to conclude that the termites keep the circles barren by burrowing underground and foraging on the roots of germinating grasses.

In summary: the termites are cultivating their own constant sources of water and food by creating and maintaining these circles. It’s a phenomenon known as ecosystem engineering.

Invisible Gorillas in Medicine

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You may be familiar with the Invisible Gorilla phenomenon, a case for “inattentional blindness” when we are focusing on something intently and miss something else entirely. The most famous version is this video in which the narrator asks the viewer to count the number of basketball passes made, while a gorilla walks by in the background…

Now, a new study from psychological scientists at Brigham and Women’s Hospital in Boston showed that 83 percent of radiologists failed to spot the animal in a CT scan, even though they went past it four times on average:

Three psychological scientists at Brigham and Women’s Hospital in Boston—Trafton Drew, Melissa Vo and Jeremy Wolfe—wondered if expert observers are also subject to this perceptual blindness. The subjects in the classic study were “naïve”—untrained in any particular domain of expertise and performing a task nobody does in real life. But what about highly trained professionals who make their living doing specialized kinds of observations? The scientists set out to explore this, and in an area of great importance to many people—cancer diagnosis.

Radiologists are physicians with special advanced training in reading various pictures of the body—not just the one-shot X-rays of the past but complex MRI, CT and PET scans as well. In looking for signs of lung cancer, for example, radiologists examine hundreds of ultra-thin CT images of a single patient’s lungs, looking for tiny white nodules that warn of cancer. It’s these expert observers that the Brigham and Women’s scientists chose to study.

They recruited 24 experienced and credentialed radiologists—and a comparable group of naïve volunteers. They tracked their eye movements as they examined five patients’ CT scans, each made up of hundreds of images of lung tissue. Each case had about ten nodules hiding somewhere in the scans, and the radiologists were instructed to click on these nodules with a mouse. On the final case, the scientists inserted a tiny image of a gorilla (an homage to the original work) into the lung. They wanted to see if the radiologists, focused on the telltale nodules, would be blind to the easily detectable and highly anomalous gorilla.

The gorilla was miniscule, but huge compared to the nodules. It was about the size of a box of matches—or 48 times the size of a typical nodule. It faded in and out—becoming more, then less opaque—over a sequence of five images.  There was no mistaking the gorilla: If someone pointed it out on the lung scan and asked, What is that? – everyone would answer: That’s a gorilla.

The gorilla seems hard to miss (photo here).  I think the idea behind this experiment was to determine whether being highly trained made people less susceptible to the phenomenon of change blindness. Doesn’t seem to be the case based on the results of this study.

Largest Prime Number Discovered

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Back when I was in college, I participated in the great GIMPS Project, searching for what is known for a Mersenne prime number (Mersenne primes are of the form (2^X)-1, with the first primes being 3, 7, 31, and 127 corresponding to X = 2, 3, 5, and 7, respectively). My computer would use its extraneous resources to help in the search, and while nothing ever came of it, it’s pretty cool to know that I made a modest contribution to the project. So it was great to learn today that the GIMPS Project found the largest prime number ever as of January 2013. The largest (known) prime number now is 2^57,885,161-1, and its discovery is noted on this post:

The new prime number is a member of a special class of extremely rare prime numbers known as Mersenne primes. It is only the 48th known Mersenne prime ever discovered, each increasingly difficult to find. Mersenne primes were named for the French monk Marin Mersenne, who studied these numbers more than 350 years ago. GIMPS, founded in 1996, has discovered all 14 of the largest known Mersenne primes. Volunteers download a free program to search for these primes with a cash award offered to anyone lucky enough to compute a new prime. Chris Caldwell maintains an authoritative web site on the largest known primes as well as the history of Mersenne primes.

To prove there were no errors in the prime discovery process, the new prime was independently verified using different programs running on different hardware. Serge Batalov ran Ernst Mayer’s MLucas software on a 32-core server in 6 days (resource donated by Novartis[2] IT group) to verify the new prime. Jerry Hallett verified the prime using the CUDALucas software running on a NVidia GPU in 3.6 days. Finally, Dr. Jeff Gilchrist verified the find using the GIMPS software on an Intel i7 CPU in 4.5 days and the CUDALucas program on a NVidia GTX 560 Ti in 7.7 days.

This largest prime number contains 17,425,170 digits. If you have a fast Internet connection, you can see how huge this number is (with all of its digits written out one by one) by clicking here. Pretty cool.

Quantum Gas Dips Below Absolute Zero

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I’ve always been taught that it’s impossible for a system to drop in temperature below absolute zero, but I guess I’ve been taught wrong:

Wolfgang Ketterle, a physicist and Nobel laureate at the Massachusetts Institute of Technology in Cambridge, who has previously demonstrated negative absolute temperatures in a magnetic system, calls the latest work an “experimental tour de force”. Exotic high-energy states that are hard to generate in the laboratory at positive temperatures become stable at negative absolute temperatures — “as though you can stand a pyramid on its head and not worry about it toppling over,” he notes — and so such techniques can allow these states to be studied in detail. “This may be a way to create new forms of matter in the laboratory,” Ketterle adds.

If built, such systems would behave in strange ways, says Achim Rosch, a theoretical physicist at the University of Cologne in Germany, who proposed the technique used by Schneider and his team. For instance, Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity.

Another peculiarity of the sub-absolute-zero gas is that it mimics ‘dark energy’, the mysterious force that pushes the Universe to expand at an ever-faster rate against the inward pull of gravity. Schneider notes that the attractive atoms in the gas produced by the team also want to collapse inwards, but do not because the negative absolute temperature stabilises them. “It’s interesting that this weird feature pops up in the Universe and also in the lab,” he says. “This may be something that cosmologists should look at more closely.”

Fascinating.

The Hum that Helps Hunt Crime

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From BBC News, an interesting piece on how forensic scientists are using a digital hum to authenticate audio recordings:

Any digital recording made anywhere near an electrical power source, be it plug socket, light or pylon, will pick up this noise and it will be embedded throughout the audio.

This buzz is an annoyance for sound engineers trying to make the highest quality recordings. But for forensic experts, it has turned out to be an invaluable tool in the fight against crime.

While the frequency of the electricity supplied by the national grid is about 50Hz, if you look at it over time, you can see minute fluctuations.

The process is known as Electric Network Frequency analysis. How this research came to be:

A decade ago, a Romanian audio specialist Dr Catalan Grigoras, now director of the National Center for Media Forensics at the University of Colorado, Denver, made a discovery: that the pattern of these random changes in frequency is unique over time.

By itself, this might be an interesting electrical curiosity. But when you take into account that most digital recordings are also embedded with this hum, it becomes a game changer.

Comparing the unique pattern of the frequencies on an audio recording with a database that has been logging these changes for 24 hours a day, 365 days a year provides a digital watermark: a date and time stamp on the recording.
It’s less clear if this technique can be used in parts of the world with multiple grids (as opposed to the U.K., which has one grid).

Theresa Christy, Elevator Guru

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The Wall Street Journal profiles Theresa Christy, who’s spent the majority of her life working with elevators and their design.

The major problem to solve:

Another problem: How many people fit in an elevator? In Asia, more people will board a car than in Europe or New York, Ms. Christy says; Westerners prefer more personal space. When she programs an elevator system she uses different weights for the average person by region. The average American is 22 pounds heavier than the average Chinese.

And an interesting bit for elevators in the Middle East:

The challenges she deals with depend on the place. At a hotel in the holy city of Mecca in Saudi Arabia, she has to make sure that the elevators can clear a building quickly enough to get most people out five times a day for prayer.

Very interesting.

The world’s fastest elevator is currently located inside Taipei 101. Here’s a list of the ten fastest elevators in the world.

The Girl That Doesn’t Feel Pain

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Justin Heckert, writing for New York Times Magazine, spent some time with Ashlyn Blocker and her parents, Tara and John. Ashlyn suffers from a rare condition called congenital insensitivity to pain in which she doesn’t feel pain:

Tara and John weren’t completely comfortable leaving Ashlyn alone in the kitchen, but it was something they felt they had to do, a concession to her growing independence. They made a point of telling stories about how responsible she is, but every one came with a companion anecdote that was painful to hear. There was the time she burned the flesh off the palms of her hands when she was 2. John was using a pressure-washer in the driveway and left its motor running; in the moments that they took their eyes off her, Ashlyn walked over and put her hands on the muffler. When she lifted them up the skin was seared away. There was the one about the fire ants that swarmed her in the backyard, biting her over a hundred times while she looked at them and yelled: “Bugs! Bugs!” There was the time she broke her ankle and ran around on it for two days before her parents realized something was wrong…

The article goes a bit into the genetic reason for Ashlyn’s insensitivity to pain, namely a mutated SCN9A gene. Interestingly, SCN9A.com lists an older NYT article about the gene.

Science Has Just Made Jurassic Park Impossible

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If you’ve ever wondered whether Jurassic Park can ever become a reality, rest assured: it can’t. According to a new study, the half-life of DNA is less than a thousand years old, so finding a perfectly preserved DNA sample that’s millions of years old is, by probabilistic measures, quite negligible.

Palaeogeneticists led by Morten Allentoft at the University of Copenhagen and Michael Bunce at Murdoch University in Perth, Australia, examined 158 DNA-containing leg bones belonging to three species of extinct giant birds called moa. The bones, which were between 600 and 8,000 years old, had been recovered from three sites within 5 kilometres of each other, with nearly identical preservation conditions including a temperature of 13.1 ºC. The findings are published in Proceedings of the Royal Society B.

By comparing the specimens’ ages and degrees of DNA degradation, the researchers calculated that DNA has a half-life of 521 years. That means that after 521 years, half of the bonds between nucleotides in the backbone of a sample would have broken; after another 521 years half of the remaining bonds would have gone; and so on.

You can read more here.