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GRAHAM YELTON

Welcome to the Body Farm

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GRAHAM YELTON

By Rene Ebersole

Beyond the border of an ordinary parking lot lies the most cutting-edge graveyard in the world … and a hands-on lab for cops and forensic anthropologists.

It was Valentine's Day when the gravediggers finished. The crew stood there waiting, their long-sleeved shirts drenched from a mixture of cold rain and sweat. At their feet were the holes—four of them—dug deep into the heavy clay. Nearby, young women and men in rubber gloves and medical gowns prepared to haul the cadavers down the hill.

Picking their way through the barren woodland, they carried 10 bodies to the burial site. Into the first ditch, the widest, they placed six corpses. In the second, they arranged three more. Just one body went into the third grave. The last was left empty. Then the gravediggers picked up their shovels and filled the holes.

Nicknamed “the body farm,” the University of Tennessee’s Forensic Anthropology Center is the oldest and most established of only four such facilities in the country. Since its inception in the early ’80s, its three wooded acres have been rife with corpses: bodies stuffed inside cars, enshrouded in plastic, rotting in shallow graves. Among them, grad students dutifully clock hours combing corpses for insects, while law enforcement agents undergo crime-scene training exercises.

It’s here, using donated cadavers, that scientists have pioneered some of the most innovative techniques in forensic science, particularly practices that help investigators pinpoint time of death—that linchpin of criminal cases that so often determines whether a killer is charged or set free. “The research we do at the facility is predominantly based on decomposition,” says center director Dawnie Steadman, “but we’re expanding that tremendously.” Now, as the bodies rest in those four anonymous graves, the center is primed to undertake a cutting-edge three-year experiment that may help scientists uncover clandestine burial sites in the world’s most dangerous conflict zones. With the help of laser technology, the reach of the body farm is about to grow exponentially, and the findings will shed light on some of history’s most heinous unsolved crimes.

Plotting the Farm

Back in 1969, the director of the Kansas Bureau of Investigation needed some advice. He had a dead cow on his hands and was trying to determine when it had died. At the time, cattle rustling was a local problem. Rustlers killed cows in the field, butchered them on the spot, hung up the meat in refrigerated trucks, and sped off. With thousands of acres to manage, ranchers rarely discovered the carcasses before several weeks had passed. Inevitably, they would call the police. But the cops were powerless—without knowing when the cows had died, there was no way to build a timeline and narrow the suspects.

The investigator figured that if anyone could age a bovine carcass, it was Bill Bass, a 41-year-old forensic anthropology professor at the University of Kansas at Lawrence. Bass sometimes lent a hand identifying skeletal remains for the agency and local law enforcement. He could look at a pile of bones and read clues in them: who the person was, what had happened. Bass’s credentials were impeccable. He’d trained at the University of Pennsylvania under the internationally renowned bone detective Wilton Krogman, known as the “medical Sherlock Holmes.” Krogman had worked on hundreds of criminal cases: everyday homicides, mob victims dug from New Jersey’s Pine Barrens, even the kidnapped Lindbergh baby. One of the major things he’d taught Bass was how teeth can shed light on a murder victim’s age and identity.

But Bass didn’t have much experience studying the remains of large livestock. When he first got the request, he did what any scientist would do. “I looked in the literature,” says Bass, now 85. “There wasn’t much there. So I called him back and said, ‘We really don’t know this. But if you can find a rancher who would give us a cow, I will look at it every day to see what’s happening.’ I put a P.S. on that letter and said, ‘We really need the rancher to give us four cows. One in spring, one in summer, one in fall, and one in winter. Because the major factor in decay is temperature.' Well, nothing ever happened with that.”

A few years later, in the spring of 1971, Bass took a new job teaching at the University of Tennessee. He moved to Knoxville, where the Tennessee medical examiner asked whether he would serve as the state’s forensic anthropologist. Bass accepted and quickly realized he wasn’t in Kansas anymore. In the sparsely populated and relatively arid Midwest, police typically brought him boxes of dry bones. In Tennessee, which had twice as many people and significantly more rainfall, the corpses were “fresher, smellier, and infinitely buggier.” When agents asked how long the bodies had been stewing, Bass could hardly say; there was no scientific basis for an answer.

So he resolved to fill the void. “In 1980, I went to the dean and said ‘I need some land to put dead bodies on,’” he recalls. “Everybody says, ‘Well, what’d he say?’" Bass continues. “He didn’t say anything. He picked up the phone and called the man on the agriculture campus who handles land, and I went over to see him.” There were a couple of wasted acres behind the University of Tennessee Medical Center where the facility used to burn its trash, the ag man said. Bass could use those.

CSI: Farm

On his newly staked plot, Bass spearheaded the first organized effort to determine what happens when a body rots. He and his students re-created crime scenes, placing bodies in shallow graves and putting them in abandoned cars. The initial investigations were fairly basic: How long until the arms fall off? When does the skull start showing through? How long before all the flesh is gone?

They weren’t surprised to find that temperature figures heavily in the rate of decomposition. A body decays faster in summer than in the winter—therefore more quickly in Florida than in Wisconsin. Is the body in the sun or shade? What was the person wearing? Bodies rot faster in wool than in cotton because wool preserves heat. Gradually, the team developed timelines and statistical formulas that could help estimate, with incredible accuracy, how long a person had been dead based on atmospheric conditions.

There are also the bugs. One of Bass’s graduate students tracked the insects that feed on corpses. Blowflies are first on the scene, and they’re crucial in helping determine time of death. As soon as the flies land, they begin laying eggs in a body’s damp orifices (eyes, mouth, nose, open wounds), and the life cycle of the insects marks the hours since death occurred. The method proved highly accurate when atmospheric conditions were taken into account, and it put entomology at the forefront of forensic science.

As the anthropology program expanded to offer a Ph.D. degree, Bass started running field courses for cops and FBI agents. He became a star member of investigative teams working on tough criminal cases, from serial murders to celebrity plane crashes. Although he’s now retired, he still consults on tough cases. “The smell turns a lot of people off,” Bass says. “But I never see a forensic case as a dead body. I see it as a challenge to figure out who that individual is and what happened to them.”

In the three decades since the body farm began, it has schooled hundreds of graduate students, law enforcement agents, and scientists. “It is impressive,” says Frank McCauley, who has worked for 25 years as an agent with the Tennessee Bureau of Investigation. McCauley was a student under Bass, and he regularly attends a recurring week-long course for law enforcement covering the basics of forensic evidence collection. “It arms you with enough knowledge and enough resources to recognize and know what you may have,” he says. “I consider Dr. Bass a national treasure.”

Graham Yelton

With hundreds of people signing up every year to donate their remains to the body farm, the center continues to grow. And recently, it acquired a new piece of land that promises to take forensic research to a whole new level. In 2007, a Vancouver-based forensic anthropologist named Amy Mundorff was rock climbing in Squamish, British Columbia. Mundorff, who carries a Prada key chain emblazoned with a skull and crossbones, was a veteran of the New York medical examiner’s office. She’d been injured as a first responder at the World Trade Center on 9/11 and then spent years identifying the remains of victims before relocating to the West Coast. With her on the cliffs was an old friend, Michael Medler, a geographer at Western Washington University.

As the two scientists scaled the face of granite masiffs, they chatted about their research. Mundorff wanted to use her experience in New York to tackle global human rights issues, but she knew about the field’s frustrations. While attempting to recover a victim of the 1995 genocide in Bosnia, one of her colleagues had followed a tip and dug around the suspected grave site, only to come up empty-handed. All the known graves in Bosnia had been excavated, Mundorff told Medler, yet more than 7000 people were still missing. Where could they be? Without better technology, the mystery might never be solved. Forensic scientists working with human rights groups were trying to use satellite imaging and aerial photography, but those methods weren’t effective at finding unknown burial sites.

“Has anyone tried lidar?” Medler asked. Lidar is a remote sensing laser technology that analyzes light reflections to detect subtle changes in the topography of the land. Medler had been introduced to it while studying the effects of forest fires. Unlike satellite scans, lidar penetrates the tree canopy, making it possible to see where the ground has been disturbed. Mundorff and Medler realized that maybe they had found a solution. Excited by the possibilities, they wanted to team up on a study immediately, but lidar was expensive. To do real experiments they’d need funding and the support of a research facility. They looked for open grants but were unsuccessful.

Finally, in 2009, Mundorff took a job as a professor at the University of Tennessee’s anthropology department and moved to Knoxville. Now she had the resources, the land, and the support of an internationally renowned institution. She called Medler and told him that they were going to test their theory. Medler was thrilled; he would consult from afar.

As soon as Mundorff arrived in Tennessee, she began doing the spadework for the lidar project while also working on a study examining the DNA in skeletal remains. Six months in, she got an email from a prospective graduate student named Katie Corcoran who had been using lidar on archaeological sites; Corcoran wanted to apply the same technology to finding mass grave sites. “I was blown away because she literally pitched our idea right back at me,” Mundorff says.

To begin the study, Mundorff would need a fresh piece of land. The center had recently acquired an adjacent property, which was quickly designated for the project. Ten bodies were ready, gifts from donors who wanted to help advance forensic science. There was just one hurdle: The new property needed fences—one for privacy and a barbed-wire one for security. This didn’t prove so easy. For three years, approvals sat snagged in university red tape. Mundorff was frustrated. At last, in February 2013, the fences went up, and by Valentine’s Day, the burial site was ready to receive the bodies.

Mundorff and her team were primarily looking at how decomposition changes the chemical content of the soil and nearby vegetation. This is the reason it had been important to secure new land, away from where other cadavers had decayed. If the extra nitrogen emitting from the corpses went into the soil, theoretically it would fertilize plants, resulting in subtle cues over the burial site—the plants would be greener and taller than the surrounding vegetation because they’d thrive in the aerated nitrogen-rich soil. That fine contrast—potentially not discernible by people traveling through a jungle on foot—might be detectable with lidar.

Mundorff and her team have another theory they’re testing using thermal imaging technology. Because decomposition creates a lot of thermal energy, imaging equipment can help identify areas where “something warm is going on,” Mundorff says. Last fall, a partnering colleague from Oak Ridge National Laboratory set up $150,000 worth of thermal equipment on the property. With temperature probes in the ground, a giant camera took pictures at five-minute intervals, allowing researchers to see the changes in temperature overnight. On the first night, Mundorff and Corcoran camped out at the center, their sleeping bags spread out on desks. They didn’t want anything to happen to the equipment. (What if it rained?) They ordered takeout Mexican and set an alarm to go off every hour so they could stumble through the dark woods to check on the camera. “Katie carried the spider stick,” says Mundorff. “She has no fears.”

The Future of Forensic Science

Today, data from the experiment is just beginning to accumulate. But what Mundorff and Corcoran suspect—and hope the experiment confirms—is that graves with multiple bodies emit more heat than those with fewer. (The empty grave is the control, representing a place where there might be a hole but no bodies.) “There are hidden graves all over the world, and a good number of them are in areas that are still dangerous,” says Mundorff. “Being able to detect them remotely is a first step in recovering the bodies and returning them to the families—and in collecting evidence if there are going to be criminal prosecutions.”

Over the next three years, about a dozen researchers and graduate students will continue monitoring the four graves. If things go as planned, the project will assist countries trying to recover from the losses of hundreds, thousands, sometimes millions of people. Human rights investigators are searching for genocide victims in Argentina, Cyprus, Bolivia, Guatemala, Uganda, Libya, Sudan, Syria, and beyond. Steadman hopes the center can play a role in helping families find their loved ones. Bass, for his part, intends to remain part of the effort by donating his own remains to the body farm. “I’ve always enjoyed teaching, and I don’t see why I should stop when I die. If the students can learn something from my skeleton, well that’s OK with me.” He’s not alone in this hope. Nearly 3300 people from all 50 states and six different countries have registered to join him.

This story originally appeared in an issue of mental_floss magazine. Subscribe here.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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May 23, 2017
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