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Duke Research - April 2011

Mark Kruse

April 26, 2011

Super Physics

It was a rainy Friday evening on campus. There was no free beer and no free t-shirts. And yet, a large and curious crowd braved the weather to hear Physics professor Mark Kruse explain the origins of the universe.

As it turns out, it’s been 14 billion years since the Big Bang and we still don’t know what went down.

“All the really interesting stuff happened less than a billionth of a second after the Big Bang,” Kruse said. The observable universe was 100 million km across (one thousand-trillionth its current size), with a toasty temperature of almost a million trillion degrees C.

“There were a lot of remarkable events going on during that first billionth of a second that we don’t fully understand and, without which, we wouldn’t be here,” Kruse said. That’s where the Large Hadron Collider comes in.

The Large Hadron Collider (LHC) near Geneva, Switzerland, is the world’s largest particle accelerator. In operation since early 2010, it uses electric fields to fling opposing beams of protons around a circular track until they reach 99.999999% the speed of light. When two protons collide (40 million times each second), a detector records the resulting debris of particles. These high-energy collisions approximate conditions found just after the Big Bang.

TestParticle tracks as seen by the ATLAS detector.

“If particles have more energy, then when you collide them, more things can happen,” Kruse said. “It’s like colliding two marbles together and getting two bowling balls. The energy of the collision is so great that it can create particles much more massive than the original particles.”

 

When these particles interact with a detector, they leave a little bit of energy behind. This energy acts like a signature, because different types of particles leave energy in different ways. According to Kruse, it’s like rolling various objects in the sand: you can identify an item by its tracks. A tennis ball doesn’t leave the same mark as a tennis shoe, and it’s the same for particles. Who knew?

Duke’s High Energy Physics Group is involved with the ATLAS detector, a 5-story-tall piece of machinery that weighs 7,000 tons (14 million pounds). Some of its components were built right here at Duke. 

3,000 kilometers of cable connect the detector’s components to computers that analyze data from particle collisions. The detector produces several petabytes of data each year. For comparison, one petabyte equals 20 million four-drawer filing cabinets filled with text, or nearly all the photos on Facebook. Computer algorithms help scientists sort through this tremendous stack of data, but it’s still a lengthy process.

“For analysis of rare processes, we must find the signal events -- sometimes only produced every trillion or so collisions -- that decay instantly into a cascade of other particles and which look like several other processes that are produced orders of magnitude more frequently.” In other words, it’s difficult. New discoveries come only after all other possibilities have been excluded. However, “we’re really preparing ourselves to discover something new,” Kruse said.

Duke’s ATLAS team hopes to answer some of the weightiest question in science: What is the origin of mass? What is dark matter, and how can we detect it? Does the Higgs-boson particle exist? Most importantly, why are we here?

“You and everyone around you are intimately related to the questions we’re trying to answer at the Large Hadron Collider,” Kruse said. “If you’re trying to look at your ancestry and figure out where you came from... this is it. In some ways, the LHC is the ultimate ancestry.com.”

To learn more, see this TED Talk by Brian Cox.

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ring-tails

April 22, 2011

Sir Richard's Possible Folly

Moving animals, like the ring-tailed lemur, from one continent to another to save the species hasn't been done often and typically isn’t successful.

But that hasn't deterred businessman and adventure tycoon Sir Richard Branson from announcing plans to import 30 ring-tailed lemurs from global zoos to his private island of Moskito, located in the Caribbean.

Branson's island lies 8,000 miles from lemurs' native home of Madagascar, where the animals have experienced more than 60 million years of independent evolution. Madagascar was great for them for most of that time, but lately lemurs are facing habitat decimation by human-induced logging, mining and political chaos.

These pressures are causing lemurs to disappear so quickly that they have become emblematic of the world's accelerating biodiversity crisis, says Anne Yoder, director of Duke University's Lemur Center, the world's largest facility for the conservation and study of these prosimian (non-ape or monkey) primates.

Yoder says that Branson's scheme to move ring-tailed lemurs, and possibly other types, to Moskito is "well intentioned," but, the plan is also " alarmingly misguided," specifically in terms of the lemurs' health and prospects for survival.

"We fear that if lemurs are released into Caribbean island habitats without proper oversight, they will perish," she says.

Yoder, along with other past and present Duke Lemur Center scientists, has spent more than 30 years monitoring lemur health and adaptation to exotic habitats, namely the center's free-range, 80-acre facility in a North Carolina forest. She says that though the lemurs can roam at the Durham-based center, each animal is examined each day to prevent and treat illnesses and to ensure survival.

While she and other lemur experts realize that "desperate times call for desperate measures," Yoder says Branson and others eager to help the lemurs should not ignore ways to protect and replenish the animal's native habitats in Madagascar.

Working with Malagasy partners and global experts in lemur conservation "is the best and only sustainable solution for assuring the survival of lemurs.  We urge Sir Richard to reach out to such partners," Yoder says.
 

Posted by ay37. 2 comments

Tags: biology, research, science communication & education

Vansh Muttreja

April 20, 2011

Vansh at TEDx

We're so proud!

Duke Research blogger Vansh Muttreja, class of 2012, presented his research at the Duke TEDx conference. When he isn't reporting and writing here, he works with Duke engineering professor Romit Roy Choudhury on gesture-based communications using smart phones. He told us about it with this post in December. ...but does he tell us he's giving a TED talk?

What the Systems Networking Research Group has come up with is a "virtual whiteboard" that allows you to write on somebody else's screen, even if you're not in the same room!

"I don't know about you guys, but I think this is magic," says Vansh.

Posted by klb25. 3 comments

Tags: engineering, lecture, students, Visualization

skydivers

April 20, 2011

Low testosterone makes men and women frisky with money

Women may no longer be able to blame men’s impulse buys on testosterone. Individuals, both women and men, with low levels of the sex hormone took just as many financial risks as those with high levels, and both groups took more gambles than individuals with average levels, a new study finds.

The results break down the stereotype that men make bigger gambles, specifically with their money, because they have more testosterone, said Steven Stanton, a post-doc in Duke’s Department of Psychology and Neuroscience and lead author of the study.

Stanton and his colleagues tested the testosterone levels of 298 people while they made choices between fixed cash rewards or gambles with chances at earning higher payouts or nothing. The participants were generally risk averse, preferring the fixed cash reward to the uncertain gamble, even though the gamble was often a better offer on average.

gamble v. fixed rewardPeople with very high or very low testosterone, compared with the average levels for their gender, took the most gambles and thus the highest risks, the team reports online in Psychological Science.

“This finding is counter-intuitive,” said Scott Huettel, the senior author of the study and an associate professor in the Department of Psychology and Neuroscience. It shows the effects of testosterone within a gender are larger than the differences between men and women and argues against the idea that testosterone levels are a primary driver of men’s risk-seeking economic choices.

The study also shows that financial risk is partially independent of testosterone, the hormone that everyone associates with other risk-seeking behaviors. There’s not just one risk-seeking phenotype—a sky-diver can be fiscally conservative, while a financial risk-taker may never go sky-diving, he said.

Huettel and Stanton think that low and high testosterone risk seekers, who made nearly identical decisions in the study, may be making their decisions via different pathways. For instance, high testosterone individuals might naturally take on risk in all settings. Low testosterone individuals, however, might have focused on taking risks only during the experiment to maximize their financial gains.

The researchers will do more studies to understand exactly what those pathways to risk-taking are and how they might be different for high and low testosterone individuals, Stanton said.

 

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Tags: behavior/psychology, research

April 12, 2011

A Global Epidemic Nobody Talks About

Worldwide, suicide is the third leading cause of death among young people aged 15 to 30. 

Young women in Nepal are now more likely to die from suicide than from child-birth. 

While maternal death is an important global health priority, “it strikes me as a little odd that we should not address avoidable premature death, such as suicide,” said Dr. Vikram Patel, a psychiatrist in India.

“Why is it that one form of suffering creates more compassion than other forms of suffering?” Patel, asked during an April 7 lecture that marked the culmination of Global Health Week at Duke.

Patel showed pictures of patients who had been abused, restrained or “locked away” by mental health institutions, denied even basic human dignity. 

“Imagine for just a moment that one of these pictures was a person with HIV/AIDS experiencing just half of the indignity that you’re seeing -- there would be global outrage,” Patel said. “Embarrassingly... there’s been no word."

He lamented the lack of attention to what he considers a global crisis. Patel blamed it on the fact that people worldwide are still uncomfortable with mental illness, either because of superstition, karma or the belief that illness occurs as a result of bad choices or behavior.

Mental disorders inflict a terrible burden on developing countries, and, because of social stigma and low access to treatment, many sufferers end up poor, no matter where they started on the economic ladder.

So what works? According to Patel, off-patent psychotropic drugs, brief psychological treatments and social interventions can treat mental illness as cost-effectively as treatments for other diseases, such as HIV/AIDS. However, treatment delivery is the real trick.

“Even when people do receive care, the kind of care they receive is terrible,” Patel said.  He asked the audience to consider two patients with chest pain -- one with schizophrenia and one without. They likely won’t receive the same treatment, he said, one reason why people with schizophrenia have lower life expectancies.&

Access to specialists is another problem. In the U.S., there are 300 million people and 50,000 psychiatrists. By comparison, India has 1.2 billion people and only 3,000 psychiatrists.

Fortunately, he said trained lay people can help close the gap by providing safe and effective interpersonal therapy for illnesses such as depression, post-natal  depression, schizophrenia, dementia and anxiety disorders.

SEE Patel's Entire Lecture on YouTube. (1 hour, 18 minutes)

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Tags: behavior/psychology, global health, lecture

particle collisions

April 12, 2011

Suspicious bump sparks new physics debate

An anomalous bump in data from the Fermi lab’s particle-smashing Tevatron could be the first hint of completely unexpected physics found in more than 50 years.

The validity of the discovery is still unclear, but the bump drew the attention of the LA Times, New York Times and several other media outlets and is now undergoing even more intense scrutiny in the physics community.

Physicists announced the result on April 7 and posted a paper to arxiv.org, a physics Web site, the night before.

They argue the bump is real and that it represents a possible new elementary particle or even a new force of nature. They also notes that there’s only about a one in a thousand chance that the result is an error in the analysis.

“I have no doubt the effect is real,” says Duke physicist Mark Kruse, who is one of several hundred co-authors on the paper but did not directly analyze the data. “The probability is small that the result is a ‘fluke’ or a statistical fluctuation, but that’s not really the main issue.”

The main issue is instead the interpretation of the bump. “I think the bump in the data is due to mis-modeling of the background particle interactions and not new physics,” Kruse says, adding that other scientists felt so strongly that the result needed more analysis that they removed their names from the new paper.

“No one can say for sure that the data currently show new physics or they don’t. The physicists have checked the anomaly against other hypotheses and the bump seems to persist,” Kruse says. “There may be something more subtle going on there, but it’s going to take a few more months to figure out.”
 

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Tags: physics

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