Archive for the ‘University of Minnesota’ Category

By Tanya Lewis

Just as humans lament not pursuing a lover or bemoan having eaten that extra slice of chocolate cake, rats may experience feelings of regret, too, new research suggests.

When rats were given the option of visiting rooms that contained different foods, and they skipped a good deal for a worse one, they glanced back at the former room, rushed through eating the snack and were more likely to tolerate longer wait times for what they considered the more desirable food , researchers found.

Furthermore, the rats’ brain activity represented the missed opportunity, suggesting the animals were, in fact, experiencing regret over their choice.

“The rat is representing the counterfactual — the ‘what might have been,'” David Redish, a neuroscientist at the University of Minnesota in Minneapolis, and senior author of the study detailed today (June 8) in the journal Nature Neuroscience.

No other studies have shown convincingly that any animal besides humans experience regret, though some studies hinted it was possible, the researchers said.

How do you define regret? You can’t exactly ask a rat if it feels regret, but even if you could, it wouldn’t be proof, just as it can be difficult to tell if a human feels regret just by asking them.

It’s important to distinguish between regret and disappointment, Redish told Live Science. Regret occurs when you make a mistake, but recognize there’s an alternate action you could have taken that would have resulted in a better outcome, he said. Disappointment happens when “the world’s just not as good as you hoped, but it’s not necessarily your fault,” he said.

To test whether rats could feel regret, Redish and his graduate student Adam Steiner designed a kind of “restaurant row” for the animals — a circular enclosure with pathways leading off it to “restaurants” with different kinds of food, which were dispensed after some delay.

As a rat passed each pathway, it heard a tone that told the animal how long it would have to wait for the food (like being told the wait time at a restaurant). Each rat had its own favorite food, such as banana or chocolate, and would wait longer to get it, Redish said. Each rat was given an hour to explore the enclosure, during which it could only move in one direction between restaurants.

If the rat passed up a good deal — for instance, bypassing a food it liked in favor of a shorter wait time — and encountered a worse deal at the next restaurant, it would glance backward at the one it passed up. Not only that, the rat rushed through eating its chosen food, much like a regretful human would, and was more likely to take a “worse deal” in the future, the researchers said.

But the rats’ behavior was only part of the story. The researchers also made electrical recordings of the rats’ brains during the task, from neurons in the orbitofrontal cortex, the part of the brain that is active in human brain scans when people feel regret. Decoding these signals allowed the researchers to “read the rat’s mind,” Redish said.

Surprisingly, when the rats were looking back at the restaurant they ultimately passed up, their brains showed a representation of entering that restaurant — not of the food they missed. The findings suggest the animals were expressing regret over their actions, rather than just disappointment, the researchers said.

If rats can feel regret, what about other animals? Redish speculates that any mammal might be capable of the feeling, because they have many of the same brain structures as rats and humans.

“Regret is something we think of as very human and very cognitive,” Redish said, but “we’re seeing that the rats are much more cognitive than we thought.”

http://www.livescience.com/46184-rats-experience-regret.html

Severe-Workplace-Clutter

Here’s a toast to the slob in the office, the gal with so much junk on her desk she can’t find her telephone. All that clutter may be part of the reason she is so creative.

For years, we’ve been told that piles of personal rubbish have got to be a liability. Now there’s a flip side to that theorem.

Researchers at the University of Minnesota decided to take a look at a long-established principle of human honesty and productivity — keep your work area clean and you will be more likely to work your tail off, stay honest, be generous with your coworkers, and on and on.

Cleanliness, after all, is next to godliness.

“We were thinking about doing a paper showing how being tidy makes people kind of do the right thing,” psychologist Kathleen Vohs, lead author of a study in the journal Psychological Science, said in a telephone interview. “And then we started challenging ourselves. Is there anything that goes along with a messy environment that could be good?”

So Vohs and her co-workers conducted a series of experiments in Holland and the United States to see if there’s an up-side to untidiness. The finding, she said, surprised even the researchers.

A messy work environment, the research suggested, can bring out a person’s creativity and lead to the birth of bold, new ideas. In other words, a less- than-perfect work environment can make a person more likely to think out of the box, or at least above the horizon of those neat people in the office.

That doesn’t mean you can set a nitwit in front of a cluttered desk and end up with another Einstein, who is said to have muttered these immortal words: “If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?”

Numerous historic photos of Einstein’s office show he was no neat freak.

No amount of clutter is going to make an empty brain creative, but this research indicates that a little clutter may bring out the freshest and most creative side of you.

“The environment doesn’t create something that isn’t already there,” Vohs said. “To the extent that you are creative, it pulls it out of you.”

Not a lot of researchers have taken up the banner of messy desks, so there’s not much to compare this work with, but the research involved a large number of participants, both young and old, and it led to these conclusions:

Sociology’s “broken windows theory” is not entirely accurate. According to Vohs’ study, that theory “posits that minor signs of disorder can cause much bigger consequences, such as delinquency and criminality.” But her research suggested a less-pristine environment can leave persons free to turn to creativity instead of crime.

“Orderly environments would encourage adherence to social convention and overall conservatism, whereas disorderly environments would encourage people to seek novelty and unconventional routes.”

“Our findings imply that varying the environment can be an effective way to shape behavior.”

Those findings resulted from three experiments in which participants were assigned tasks while seated in a neat, orderly office, or in an office that was identical in every way except it was filled with clutter, such as papers on the floor and stacks of files on the desk.

Thirty-four Dutch students were tested to see if the orderliness of the room had any effect on their generosity and sense of needing to do the right thing. At the end of the experiment, for example, the students were asked to contribute to a worthy cause.

Some 82 percent of the students in the orderly room contributed money, compared to only 47 percent in the disorderly room.

As they left the room, they were offered a treat, either an apple or a piece of candy. Participants from the orderly room were more than three times as likely to take the apple. Moral: orderliness brought out a need do the right thing.

In a second experiment, participants were told to come up with new uses for ping-pong balls to help a manufacturer.

“Participants in the disorderly room generated more highly creative ideas than did participants in the orderly room,” the study said.

In the final experiment, 188 American adults were asked to pick from a list of new options to be added to a restaurant’s menu. Participants from the orderly room were far more likely to pick a healthy option than were participants from a disorderly room.

The researchers described the findings as “robust,” meaning there was little question that the environment directly influenced the behavior of the participants.

“Disorderly environments seem to inspire breaking free of tradition, which can produce fresh insights,” the researchers concluded. “Orderly environments, in contrast, encourage convention and playing it safe.”

Something good can come from either setting, Vohs said. A tidy workplace may help people walk a straight line. A messy desk may help them figure out a new way to keep from walking at all.

http://abcnews.go.com/Technology/tidy-messy-environment-impact-decisions-behavior-study/story?id=19909678

foam_copy
A sample of the manure foam that caused an explosion that lifted a hog barn two feet off the ground and blew a man 20 feet away from where he had been standing.

When you hear about foam in the context of food, you might think of the culinary innovations of the Spanish chef Ferran Adrià, who’s famous for dishes like apple caviar with banana foam.

But this post is about a much less appetizing kind of foam. You see, starting in about 2009, in the pits that capture manure under factory-scale hog farms, a gray, bubbly substance began appearing at the surface of the fecal soup. The problem is menacing: As manure breaks down, it emits toxic gases like hydrogen sulfide and flammable ones like methane, and trapping these noxious fumes under a layer of foam can lead to sudden, disastrous releases and even explosions. According to a 2012 report from the University of Minnesota, by September 2011, the foam had “caused about a half-dozen explosions in the upper Midwest…one explosion destroyed a barn on a farm in northern Iowa, killing 1,500 pigs and severely burning the worker involved.”

The foam grows to a thickness of up to four feet, and scientists can’t explain the phenomenon.

Angela Kent, an associate professor in the department of natural resources and environmental sciences at the University of Illinois, reports that “manure foaming” is “still a very serious problem among pork producers in the Midwest.” Scientists have still not been able to finger the cause of it, but “we are in the midst of a large multi-institution investigation focused on finding the cause of this very serious problem.”

Larry Jacobson, a professor and extension engineer at the University of Minnesota, reports that around 25 percent of operations in the hog-intensive regions of Minnesota, Illinois, and Iowa are experiencing foam—and “the number may be higher, because some operators might not know that they have it.”

He added that the practice of feeding hogs distillers grains, the mush leftover from the corn ethanol process, might be one of the triggers. Distillers grains entered hog rations in a major way around the same time that the foam started emerging, and manure from hogs fed distillers grains contains heightened levels of undigested fiber and volatile fatty acids—both of which are emerging as preconditions of foam formation, he said. But he added that distillers grains aren’t likely the sole cause, because on some operations, the foam will emerge in some buildings but not others, even when all the hogs are getting the same feed mix.

A solution seems to be emerging, Jacobson reports: Dump a bit of monensin, an antibiotic widely used to make cows grow faster, directly into the foam-ridden pit. At rather low levels, about 25 pounds of the stuff will treat a typical 500,000 gallon pit—the stuff effectively breaks up the foam, likely by altering the mix of microbes present. No other treatment has been shown to work consistently, Jacobson said.

http://www.motherjones.com/tom-philpott/2013/05/menace-manure-foam-still-haunting-huge-hog-farms

starve

There’s more to malnutrition than poor diet. Two complementary studies suggest that microbes have an important role to play in both the onset and treatment of a poorly understood form of malnutrition called kwashiorkor.

Malnutrition, the leading cause of death among children worldwide, remains something of a puzzle. It is unclear, for instance, why some children are especially prone to becoming malnourished when siblings they live with appear to fare better.

Now Jeffrey Gordon at Washington University in St Louis, Missouri, and his colleagues have found that a child’s risk of malnutrition may come down to the microbes in his or her guts.

Working in southern Malawi, the team identified sets of identical and non-identical twins in which one child had kwashiorkor – thought to be caused by a lack of protein – and the other did not, despite the shared genetics and diet. Gordon’s team took faecal samples from three sets of twins and transplanted the samples into the guts of mice, which were then fed a typical nutrient-poor Malawian diet.

Mouse weight lossAll of the mice lost some weight. However, some lost significantly more weight, and more quickly, than others. Further investigation showed that these mice had all received a faecal sample from children with kwashiorkor.

The finding strongly hinted that the mice had picked up a kwashiorkor-like condition from the microbes within the faecal implant, so the researchers studied the rodents’ gut flora. They found higher than normal levels of bacteria associated with illnesses such as inflammatory bowel disease.

The results suggest pathogenic microbes may heighten the problems of malnutrition in some children, says Jeremy Nicholson at Imperial College London, a member of the study team. “There’s a lot of work revolving around obesogenesis – how given a standard diet one set of bugs might make more calories available than another set,” he says. “But the other side of that coin is that maybe particular bugs can restrict calorie availability and exacerbate a poor diet.”

Indi Trehan at Washington University, another member of the research team, agrees. “I think it is correct that there are more factors than simple food insecurity at play in terms of malnutrition,” he says.

Antibiotic aidTrehan is lead author on a second new study, which examines how children with kwashiorkor respond when given nutrient-rich therapeutic diets. Trehan’s team found that the children were significantly less likely to become malnourished once the dietary treatment had ended if they were given a course of antibiotics along with the diet.

Together, the studies help us understand the role that infections might play in malnutrition, says Trehan. This might point towards a future in which microbial concoctions can be tailored to guard against such infections and treat specific conditions, suggests Nicholson.

Alexander Khoruts at the University of Minnesota in Minneapolis has been using faecal transplants to treat resistant Clostridium difficile disease in humans. “It is likely that microbiota are involved in pathogenesis of many other diseases, and it is possible that faecal transplants may be an approach to treat those as well,” he says. But because gut bacteria are so complex, he thinks more research will be needed to develop appropriate microbe-based therapies.

http://www.newscientist.com/article/dn23127-abnormal-gut-bacteria-linked-to-severe-malnutrition.html

As a young theorist in Moscow in 1982, Mikhail Shifman became enthralled with an elegant new theory called supersymmetry that attempted to incorporate the known elementary particles into a more complete inventory of the universe.

“My papers from that time really radiate enthusiasm,” said Shifman, now a 63-year-old professor at the University of Minnesota. Over the decades, he and thousands of other physicists developed the supersymmetry hypothesis, confident that experiments would confirm it. “But nature apparently doesn’t want it,” he said. “At least not in its original simple form.”

With the world’s largest supercollider unable to find any of the particles the theory says must exist, Shifman is joining a growing chorus of researchers urging their peers to change course.

In an essay posted last month on the physics website arXiv.org, Shifman called on his colleagues to abandon the path of “developing contrived baroque-like aesthetically unappealing modifications” of supersymmetry to get around the fact that more straightforward versions of the theory have failed experimental tests. The time has come, he wrote, to “start thinking and developing new ideas.”

But there is little to build on. So far, no hints of “new physics” beyond the Standard Model — the accepted set of equations describing the known elementary particles — have shown up in experiments at the Large Hadron Collider, operated by the European research laboratory CERN outside Geneva, or anywhere else. (The recently discovered Higgs boson was predicted by the Standard Model.) The latest round of proton-smashing experiments, presented earlier this month at the Hadron Collider Physics conference in Kyoto, Japan, ruled out another broad class of supersymmetry models, as well as other theories of “new physics,” by finding nothing unexpected in the rates of several particle decays.

“Of course, it is disappointing,” Shifman said. “We’re not gods. We’re not prophets. In the absence of some guidance from experimental data, how do you guess something about nature?”

Younger particle physicists now face a tough choice: follow the decades-long trail their mentors blazed, adopting ever more contrived versions of supersymmetry, or strike out on their own, without guidance from any intriguing new data.

“It’s a difficult question that most of us are trying not to answer yet,” said Adam Falkowski, a theoretical particle physicist from the University of Paris-South in Orsay, France, who is currently working at CERN. In a blog post about the recent experimental results, Falkowski joked that it was time to start applying for jobs in neuroscience.

“There’s no way you can really call it encouraging,” said Stephen Martin, a high-energy particle physicist at Northern Illinois University who works on supersymmetry, or SUSY for short. “I’m certainly not someone who believes SUSY has to be right; I just can’t think of anything better.”

Supersymmetry has dominated the particle physics landscape for decades, to the exclusion of all but a few alternative theories of physics beyond the Standard Model.

“It’s hard to overstate just how much particle physicists of the past 20 to 30 years have invested in SUSY as a hypothesis, so the failure of the idea is going to have major implications for the field,” said Peter Woit, a particle theorist and mathematician at Columbia University.

The theory is alluring for three primary reasons: It predicts the existence of particles that could constitute “dark matter,” an invisible substance that permeates the outskirts of galaxies. It unifies three of the fundamental forces at high energies. And — by far the biggest motivation for studying supersymmetry — it solves a conundrum in physics known as the hierarchy problem.

The problem arises from the disparity between gravity and the weak nuclear force, which is about 100 million trillion trillion (10^32) times stronger and acts at much smaller scales to mediate interactions inside atomic nuclei. The particles that carry the weak force, called W and Z bosons, derive their masses from the Higgs field, a field of energy saturating all space. But it is unclear why the energy of the Higgs field, and therefore the masses of the W and Z bosons, isn’t far greater. Because other particles are intertwined with the Higgs field, their energies should spill into it during events known as quantum fluctuations. This should quickly drive up the energy of the Higgs field, making the W and Z bosons much more massive and rendering the weak nuclear force about as weak as gravity.

Supersymmetry solves the hierarchy problem by theorizing the existence of a “superpartner” twin for every elementary particle. According to the theory, fermions, which constitute matter, have superpartners that are bosons, which convey forces, and existing bosons have fermion superpartners. Because particles and their superpartners are of opposite types, their energy contributions to the Higgs field have opposite signs: One dials its energy up, the other dials it down. The pair’s contributions cancel out, resulting in no catastrophic effect on the Higgs field. As a bonus, one of the undiscovered superpartners could make up dark matter.

“Supersymmetry is such a beautiful structure, and in physics, we allow that kind of beauty and aesthetic quality to guide where we think the truth may be,” said Brian Greene, a theoretical physicist at Columbia University.

Over time, as the superpartners failed to materialize, supersymmetry has grown less beautiful. According to mainstream models, to evade detection, superpartner particles would have to be much heavier than their twins, replacing an exact symmetry with something like a carnival mirror. Physicists have put forward a vast range of ideas for how the symmetry might have broken, spawning myriad versions of supersymmetry.

But the breaking of supersymmetry can pose a new problem. “The heavier you have to make some of the superpartners compared to the existing particles, the more that cancellation of their effects doesn’t quite work,” Martin explained.

Most particle physicists in the 1980s thought they would detect superpartners that are only slightly heavier than the known particles. But the Tevatron, the now-retired particle accelerator at Fermilab in Batavia, Ill., found no such evidence. As the Large Hadron Collider probes increasingly higher energies without any sign of supersymmetry particles, some physicists are saying the theory is dead. “I think the LHC was a last gasp,” Woit said.

Today, most of the remaining viable versions of supersymmetry predict superpartners so heavy that they would overpower the effects of their much lighter twins if not for fine-tuned cancellations between the various superpartners. But introducing fine-tuning in order to scale back the damage and solve the hierarchy problem makes some physicists uncomfortable. “This, perhaps, shows that we should take a step back and start thinking anew on the problems for which SUSY-based phenomenology was introduced,” Shifman said.

But some theorists are forging ahead, arguing that, in contrast to the beauty of the original theory, nature could just be an ugly combination of superpartner particles with a soupçon of fine-tuning. “I think it is a mistake to focus on popular versions of supersymmetry,” said Matt Strassler, a particle physicist at Rutgers University. “Popularity contests are not reliable measures of truth.”

In some of the less popular supersymmetry models, the lightest superpartners are not the ones the Large Hadron Collider experiments have looked for. In others, the superpartners are not heavier than existing particles but merely less stable, making them more difficult to detect. These theories will continue to be tested at the Large Hadron Collider after it is upgraded to full operational power in about two years.

If nothing new turns up — an outcome casually referred to as the “nightmare scenario” — physicists will be left with the same holes that riddled their picture of the universe three decades ago, before supersymmetry neatly plugged them. And, without an even higher-energy collider to test alternative ideas, Falkowski says, the field will undergo a slow decay: “The number of jobs in particle physics will steadily decrease, and particle physicists will die out naturally.”

Greene offers a brighter outlook. “Science is this wonderfully self-correcting enterprise,” he said. “Ideas that are wrong get weeded out in time because they are not fruitful or because they are leading us to dead ends. That happens in a wonderfully internal way. People continue to work on what they find fascinating, and science meanders toward truth.”

From Simons Science News (find the original story here)

http://www.scientificamerican.com/article.cfm?id=supersymmetry-fails-test-forcing-physics-seek-new-idea