Friday, February 26, 2010

Should killer whales be captive?

Photo of orcas in the wild by Paul Chetirkin/Marine Photobank

The tragic death of killer whale trainer Dawn Brancheau in Florida, after a 12,000-pound orca named Tilikum pulled her into a tank, has raised new questions about the confinement of dolphins and whales in theme parks. eScienceCommons discussed the topic with Emory neuroscientist Lori Marino, an expert on the brains of cetaceans, which include porpoises, dolphins and whales.

Q: What are some common misconceptions about killer whales, also known as orcas?

Marino: Killer whales are actually dolphins. They are called whales because they are the largest dolphins, but they are in the same family as the bottlenose dolphin. Although they are top predators, they are not naturally aggressive to people. I have colleagues who research orcas and swim with them in the wild. People will go out in very small boats and paddle among orcas. They could easily reach up and grab you and gobble you up. And yet there is not a single incident of an orca injuring, let alone killing, a person in the wild.

Q: What do we know about killer whale intelligence?

Marino: The orca brain is the most convoluted brain on the planet. These are very, very intelligent animals with major, impressive brains.

I think people would be surprised to know that orcas form cultures in the oceans, and they pass these on through generations. It’s stunning. Different groups of orcas make distinct sounds and we call these dialects. It’s like a Brooklyn accent versus a Manhattan accent.

Orcas have really creative ways of getting prey. In the Arctic, a sea lion may try to escape them by getting on a floating chunk of ice. A group of orcas will form a line and rush forward together to create a wave to make the ice chunk wobbly and throw the sea lion into the water. You see a lot of group cooperation like this among orcas.

Q: Why are you so strongly against keeping killer whales and other cetaceans in theme parks?

Marino: The normal range of an orca is several 100 kilometers per day, and they like to dive really deep. They don’t have room in these tanks to swim as far as they would like to. There is no evidence that they kill each other in the wild, but they have been known to kill each other in captivity. When you take all of that energy and put it into a small tank, a lot of stress builds up and it’s like a perfect storm waiting to happen.

I understand that people want to see these animals up close, but I want people to understand the price that the animals are paying. What happened at SeaWorld is tragic all around, for the trainer who lost her life and for the whale.

What do you think? Should killer whales be kept in theme parks for entertainment?

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Thursday, February 25, 2010

The anger myth: Read this before blowing up

Emory psychologist Scott Lilienfeld, author of "50 Great Myths of Popular Psychology," and his co-authors write in Scientific American Mind about the bewildering mix of fact and fallacy in pop psych lore:

"Popular media assure us that anger is a monster we must tame by 'letting off steam,' 'blowing our top' and 'getting things off our chest.' In the 2003 movie Anger Management, the meek hero (played by Adam Sandler) is falsely accused of 'air rage' on a flight, causing a judge to order him to attend an anger management group run by psychiatrist Buddy Rydell (played by Jack Nicholson). At Rydell’s suggestion, Sandler’s character tosses dodgeballs at schoolchildren and throws golf clubs to purge his anger.

"Rydell’s advice echoes the counsel of many self-help authors. One suggested that rather than 'holding in poisonous anger,' it is better to 'punch a pillow or a punching bag. And while you do it, yell and curse and moan and holler.'

"Yet more than 40 years of research reveals that expressing anger actually amplifies aggression. In one study, people who pounded nails after someone insulted them became more critical of that person than did their counterparts who did not pound nails. Other research shows that playing aggressive sports, such as football, actually boosts self-reported hostility. And a review of 35 studies ... suggests that playing violent video games such as Manhunt, in which participants rate assassinations on a five-point scale, heightens aggression in the laboratory and in everyday social situations."

Read the full article.

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Wednesday, February 24, 2010

Invention lets art sleuth see through walls

Four hundred and fifty years ago, a Leonardo da Vinci mural of clashing soldiers disappeared from the hall where Florence’s political leaders used to meet. Art sleuth Maurizio Seracini has strong clues that the "The Battle of Anghiari" lies hidden behind a brick wall, built during a renovation of the hall. In order to prove it, however, he needs to see through the wall.

Emory physicist Ray DuVarney came up with an idea, based on the fact that paints get colors from different chemical elements. White paint from da Vinci’s time contained lead, for instance, and red paint contained mercury. DuVarney reasoned that shooting a beam of neutrons through the brick wall should induce the paints’ atoms to send back gamma rays, each emitting an energy distinctive to a particular color. These “pixels” of color could then be plotted onto a graph to indicate whether they formed an image akin to the missing mural.

"This is a passion project," DuVarney says. "It's more than a physics problem. It's about finding one of the lost wonders of the world."

Seracini has tested the technology successfully, and is now building a portable machine to scan the actual wall in Florence. The mystery of one of the world’s greatest missing masterpieces may be solved by the end of this year. If it works, it will open a new era in art sleuthing. As Seracini told Scholastic’s Free Library: “Once we have built this portable unit, we will use this technology to search for hundreds of murals hidden everywhere on the planet.”

Physicist sheds light on da Vinci mystery

Tuesday, February 23, 2010

Tiny aphids hold big surprises in genome

Pea aphids, expert survivors of the insect world, appear to lack major biological defenses, according to the first genetic analysis of their immune system.

“It’s surprising,” says Emory biologist Nicole Gerardo, who led the study, published this week in Genome Biology. "Aphids have some components of an immune system, but they are missing the genes that we thought were critical to insect immunity."

Pea aphids are major agricultural pests and also important biological models for studies of insect-plant interactions, symbiosis, virus vectoring and genetic plasticity. These resilient insects thrive despite a host of enemies, including parasitic wasps, lady bugs, fungal pathogens and frustrated farmers and gardeners the world over.

The immune-system analysis is among a group of findings generated by the International Aphid Genomics Consortium, which just published the full sequence of the pea aphid genome, and sponsored dozens of in-depth analyses of different areas of the sequence.

"This is the first look at the genome of a whole group of insects we know little about," says Gerardo, an evolutionary biologist who focuses on host-parasite interactions.

All insects previously sequenced belong to a group that undergoes metamorphosis. Pea aphids, however, belong to an insect group known as basel hemimetablous – meaning they are born looking like tiny adults.
"We went into this expecting to find the same set of immune-system genes that we've seen in the genomes of flies, mosquitoes and bees," Gerardo says. “Given these missing genes, it seems that aphids have a weak immune system. Our next step is to figure out how they protect themselves.” One hypothesis is that aphids may compensate for their lack of immune defenses by focusing on reproduction. From birth, a female aphid contains embryos that also contain embryos.

“She is born carrying her granddaughters,” Gerardo says. “In a lab, a female aphid can produce up to 20 copies of herself per day. About 10 days later, those babies will start producing their own offspring.”

Over 50 million years, aphids have evolved complex relationships with beneficial bacteria that supply them with nutrients or protect them from predators and pathogens. It’s possible that the weak immune response in aphids developed as a way to keep from killing off these beneficial microbes, Gerardo says. “A key question is whether these microbes could have changed the aphid genome, or changed how the aphid uses its genes.”

Further study of how the aphid immune system interacts with microbes could yield better methods for controlling them in agriculture.

Aphids are not just pests, Gerardo says. They are also potential resources for questions related to human health.

"Humans need beneficial bacteria for proper digestion in the gut and to protect against cavities in the teeth," she says. "Some people feel sick when they take antibiotics because the drug kills off all the beneficial bacteria. If we can study the process of how to keep beneficial bacteria while clearing out harmful bacteria across several organisms, including aphids, we might be able to understand it better."

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Monday, February 22, 2010

Bad science in films bugs physicist

The next time you see a sci-fi film with people battling insects as big as houses, consider this: An insect scaled up to that size would collapse under its own weight, according to physicist Sidney Perkowitz.

From the Guardian in London:

"Science fiction movies should be allowed only one major transgression of the laws of physics, according to a US professor who has won backing from a number of his peers after creating a set of guidelines for Hollywood.

"The guidelines are by Sidney ­Perkowitz, a professor of physics at Emory University and a member of the Science and Entertainment Exchange, an advisory body run by the US National Academy of Sciences.

"The Science and Entertainment Exchange is backed by Dustin Hoffman, Harvard psychologist Steven Pinker and Lawrence Kasdan, who wrote the screenplays for The Empire Strikes Back and Raiders of the Lost Ark. Perkowitz said: 'The hope is that it will get better science into films while still making them interesting.'"

Read the full article.

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Friday, February 19, 2010

Biology may not be so complex after all

By Carol Clark

Centuries ago, scientists began reducing the physics of the universe into a few, key laws described by a handful of parameters. Such simple descriptions have remained elusive for complex biological systems – until now.

Emory biophysicist Ilya Nemenman has identified parameters for several biochemical networks that distill the entire behavior of these systems into simple equivalent dynamics. The discovery may hold the potential to streamline the development of drugs and diagnostic tools, by simplifying the research models.

The resulting paper, now available online, will be published in the March issue of Physical Biology.

"It appears that the details of the complexity of these biological systems don't matter, as long as some aggregate property, which we've calculated, remains the same," says Nemenman, associate professor of physics and biology. He conducted the analysis with Golan Bel and Brian Munsky of the Los Alamos National Laboratory.

The simplicity of the discovery makes it “a beautiful result,” Nemenman says. “We hope that this theoretical finding will also have practical applications.”

He cites the air molecules moving about his office: “All of the crazy interactions of these molecules hitting each other boils down to a simple behavior: An ideal gas law. You could take the painstaking route of studying the dynamics of every molecule, or you could simply measure the temperature, volume and pressure of the air in the room. The second method is clearly easier, and it gives you just as much information.”

Nemenman wanted to find similar parameters for the incredibly complex dynamics of cellular networks, involving hundreds, or even thousands, of variables among different interacting molecules. Among the key questions: What determines which features in these networks are relevant? And if they have simple equivalent dynamics, did nature choose to make them so complex in order to fulfill a specific biological function? Or is the unnecessary complexity a “fossil record” of the evolutionary heritage?

For the Physical Biology paper, Nemenman and co-authors investigated these questions in the context of a kinetic proofreading (KPR) scheme.

KPR is the mechanism a cell uses for optimal quality control as it makes protein. KPR was predicted during the 1970s and it applies to most cellular assembly processes. It involves hundreds of steps, and each step may have different parameters.

Nemenman and his colleagues wondered if the KPR scheme could be described more simply. "Our calculations confirmed that there is, in fact, a key aggregate rate," he says. "The whole behavior of the system boils down to just one parameter."

That means that, instead of painstakingly testing or measuring every rate in the process, you can predict the error and completion rate of a system by looking at a single aggregate parameter.

Charted on a graph, the aggregate behavior appears as a straight line amid a tangle of curving ones. “The larger and more complex the system gets, the more the aggregate behavior is visible,” Nemenman says. “The completion time gets simpler and simpler as the system size goes up.”

Nemenman is now collaborating with Emory theoretical biologist Rustom Antia, to see if the discovery can shed light on the processes of immune cells. In particular, they are interested in the malfunction of certain immune receptors involved in most allergic reactions.

"We may be able to simplify the model for these immune receptors from about 3,000 steps to three steps," Nemenman says. "You wouldn't need a supercomputer to test different chemical compounds on the receptors, because you don't need to simulate every single step, just the aggregate."

Just as the discovery of an ideal gas law led to the creation of engines and automobiles, Nemenman believes that such simple biochemical aggregates could drive advancements in health.

Biochemical cell signals quantified for first time

Thursday, February 18, 2010

What's in a dolphin's tool kit?

Dolphins have been seen using sponges, perhaps to protect their mouths from coral. And some bottlenose dolphins create rings of mud with their tails to trap fish.

"You don't need hands to create tools, you just need a clever mind," says Emory neuroscientist Lori Marino, an expert in dolphin neuroanatomy. Marino is speaking at the American Association for the Advancement of Science annual meeting on Sunday, Feb. Feb. 21, about how the high intelligence of dolphins calls for us to rethink how we treat them.

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Read more about Marino's work in the Washington Post.

Photo by Brenda McCowan shows bottlenose dolphins playing with a bubble ring they created.

Wednesday, February 17, 2010

Breathe in, breathe out, be happy

Drawing by Erica Endicott shows Tibetan script for parts of the atom. The words were created for the Tibetan language by the Emory-Tibet Science Initiative.

Nascent Buddhist April Bogle writes in Emory Magazine:

"I want to be happy. Coming to the end of a terrible decade that has included two debilitating divorces, a wrenching child custody battle, and my beloved father’s diagnosis of Alzheimer’s disease, I’ve decided it’s time to figure out this happiness thing. ...

"The journey took me to Washington, D.C., where Buddhist monk and author Matthieu Ricard, actor Richard Gere, and Daniel Goleman, author of "Emotional Intelligence" and several other books on the science of the mind, were coming together to help raise money for the Emory-Tibet Science Initiative. A joint project of the University and the Tibetan monastic academic system, the initiative is perhaps the boldest and most challenging program in the Emory-Tibet Partnership."

Read more in Emory Magazine about Bogle's first-hand experience with how Emory is applying modern Western science to ancient Eastern tradition -- and why Richard Gere thinks it will change the world.


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Tuesday, February 16, 2010

Galileo's view of the sky

NASA photo of Halley Comet from 1986.

Emory celebrated Galileo’s birthday Feb. 15 with a talk by Vatican astronomer Brother Guy Consolmagno.

“Because of light pollution, I suspect many of the undergraduates in this room have never seen the Milky Way, which is a real tragedy,” he said.

Consolmagno told of his own “soul-shaking experience” of seeing his first comet. He described the 1618 comet controversy, when Galileo asserted that comets were an optical illusion, and how he ridiculed a more accurate theory by Jesuit mathematician Orazio Grassi. The controversy was among the circumstances contributing to Galileo being put on trial by the Catholic Church, for championing the idea of a sun-centered solar system. He ended his life under house arrest.

“Both Galileo and Grassi reacted with deep passion to this comet, and both were guilty of seeing more of what they wanted to see than what was actually there,” Consolmagno said.

“Galileo was brilliant. He got so many things right that the things he got wrong stick out like sore thumbs,” he added. “Scientific truth is at best always incomplete. No one who wants to study comets today bothers to read Grassi or Galileo, because our understanding has come so much further. And a textbook on comets in 2410 will make our work today look pretty obsolete. At least, I hope so.”

Check out this hilarious video of Consolmagno's appearance on "The Colbert Report."
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Thursday, February 11, 2010

How to make your Valentine last forever

Are you seeking sustainable love?

Then don't toss all your Valentine's Day boxes after you eat the chocolates. In the video above, Emory paleontologist Tony Martin shows how to scientifically recycle them as fossil containers. You, too, can change a perishable sentiment into something to last for millennia.

If you don't receive any Valentines, you may want to read up on the research of Larry Young, Emory's "love doctor." He's studying brain chemicals linked to the ability to form lasting bonds of affection.

What is the chemical basis of love?

Wednesday, February 10, 2010

'Avatar' theme can make you blue

Avatar: An incarnation of a Hindu god; an embodiment of a view of life; a personification of a computer user; and, now, a science fiction movie.

Emory biologist Alexander Escobar interprets "Avatar" the movie this way: “The perspective that the natives have and the perspective that the miners have is very different. The technological perspective is that you can take something apart, and you can put new parts into it, just like any machine. It’s pretty much the dominant reality we have in the western world. In the movie, the natives see (mining) as taking apart their mother. And if you think about something that is a system, a whole, that works together, you can’t go in and start taking pieces out. It begins to fall apart. I think part of the reason that this movie has become so popular is that this sort of clash between these two world views is playing itself out in our world. “

Escobar is the author of a new book, “Mythology for the New World: A Synthesis of Science and Religion.”

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Tuesday, February 9, 2010

Scenes from our wild campus

Foxes, deer, otters and ... beavers? Keep your eyes peeled. You never know what you'll see strolling about Emory's woodsy campus. But please don't pet the wildlife.

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Monday, February 8, 2010

A brainy time traveler

By Carol Clark

Anthropologist James Rilling, founder of Emory's Laboratory for Darwinian Neuroscience, is mapping the evolution of our minds.

"It's like the space program," he explains. "We believe that we should be trying to understand the universe around us. I feel the same way about exploring the brain to learn who we are and how we got here."

The Milwaukee native came to Emory as a graduate student, drawn by the anthropology department's emphasis on human biology. "It's a definite strength," says Rilling, citing the department's access to the Yerkes National Primate Research Center and the quality of the faculty.

For his dissertation, Rilling used fMRI to compare the neuroanatomy of humans and 10 other primate species at Yerkes. The 1998 study was the first in-depth look at whether the human brain is merely a scaled-up version of the brains of other primates.

“We found that human temporal lobes are larger than you would expect for a primate of our brain size,” Rilling says. “We’ve done subsequent work that shows this larger size is likely due to the evolution of language pathways in humans.”

The Laboratory for Darwinian Neuroscience is a leader in the use of non-invasive imaging technology to compare the neuroanatomy of living primates.

Much previous work has focused on the gray matter of brains. Rilling's group is the only one in the world using diffusion tensor imaging (DTI) to compare the white matter connections of monkeys, humans and our closest relative, chimpanzees. White matter contains the fiber tracts that connect and "wire" the brain.

“We’ve discovered a difference in both the size and the trajectory of the fiber tract that runs between Wernicke’s area in the left temporal lobe and Broca’s area in the left inferior frontal cortex,” Rilling says. Broca’s area is involved in speech production and Wernicke’s in understanding language. In humans, the pathway that connects the two areas is much more massive, and projects beyond Wernicke’s area down to the ventral part of the temporal lobe.

“There’s something special going on in the human brain with that pathway,” Rilling says. “It’s organized differently than in other primates.”

The lab is also exploring the neural basis of human cognition and behavior. One of its studies showed that reciprocation in humans is tied to activation of a reward pathway in the brain. “The magnitude of that reaction correlated to how likely the person was to cooperate in the future,” Rilling says.

Why are some people more cooperative than others? How does the brain change with age? What promotes social bonding and attachment? These are just a few of the many research questions the lab is tackling.

"We want to start to understand individual human differences in social behavior, at both the genetic and neurological levels," Rilling says.

He's particularly interested in understanding why some men are more nurturing as fathers than others. “It’s important to have someone besides the mother involved in a child’s care. I think one way that we could improve childhood development is to have more committed dads,” says Rilling, who is married to a psychiatrist and hopes to one day become a father.

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Friday, February 5, 2010

Economists do it with models

Heard any good economist jokes lately? The recent Economics Convention in Atlanta was full of them, as the so-called "dismal science" celebrated the fact that sex and humor sell, even during a recession.

PBS NewsHour covered the event, including a presentation by Emory's Hugo Mialon on the economics of faking ecstasy in lovemaking.

"This paper was suggested to me by my lovely wife and colleague, Sue Mialon," he says.

Listen to the full report by PBS. Believe it or not, there is even a knock-knock joke.

Who's more likely to fake it?

Thursday, February 4, 2010

Grounded cognition gives your mind a hand

Before you read this, pour yourself a cup of hot tea.

Now, sit up straight. Smile. Hold that warm cup in your hand. Research is showing that these kinds of actions can positively influence what you think about a piece of writing.

"All the states of your body affect how you think. So does the environment," says Lawrence Barsalou, an Emory psychologist and a leading researcher of grounded cognition -- the idea that thought is shaped by bodily states. And vice-versa.

For instance, you may feel anxious about an upcoming presentation. Just thinking about forgetting your speech can produce the same physical stress reactions that occur when you actually are standing in front of a group of people and draw a blank.

"We're just barely beginning to understand the mechanisms, at a detailed and specific level, that operate to produce these experiences," Barsalou says.

We are entering a new era in psychology research, says Barsalou, who is especially interested in how meditation might be used to alleviate stress reactions.

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Monday, February 1, 2010

Putting teeth into Barker hypothesis

Teeth from a site near Cuzco, Peru, show grooves of enamel damage. Source: Valerie Andrushko.

By Carol Clark

Ancient human teeth are telling secrets that may relate to modern-day health: Some stressful events that occurred early in development are linked to shorter life spans.

"Prehistoric remains are providing strong, physical evidence that people who acquired tooth enamel defects while in the womb or early childhood tended to die earlier, even if they survived to adulthood," says Emory anthropologist George Armelagos.

Armelagos led a systematic review of defects in teeth enamel and early mortality recently published in Evolutionary Anthropology. The paper is the first summary of prehistoric evidence for the Barker hypothesis – the idea that many adult diseases originate during fetal development and early childhood.

"Teeth are like a snapshot into the past," Armelagos says. "Since the chronology of enamel development is well known, it's possible to determine the age at which a physiological disruption occurred. The evidence is there, and it's indisputable." 

The Barker hypothesis is named after epidemiologist David Barker, who during the 1980s began studying links between early infant health and later adult health. The theory, also known as the Developmental Origins of Health and Disease Hypothesis (DOHaD), has expanded into wide acceptance.

As one of the founders of the field of bioarcheology, Armelagos studies skeletal remains to understand how diet and disease affected populations. Tooth enamel can give a particularly telling portrait of physiological events, since the enamel is secreted in a regular, ring-like fashion, starting from the second trimester of fetal development. Disruptions in the formation of the enamel, which can be caused by disease, poor diet or psychological stress, show up as grooves on the tooth surface.

Armelagos and other bioarcheologists have noted the connection between dental enamel and early mortality for years. For the Evolutionary Biology paper, Armelagos led a review of the evidence from eight published studies, applying the lens of the Barker hypothesis to remains dating back as far as 1 million years.

One study of a group of Australopithecines from the South African Pleistocence showed a nearly 12-year decrease in mean life expectancy associated with early enamel defects. In another striking example, remains from Dickson Mounds, Illinois, showed that individuals with teeth marked by early life stress lived 15.4 years less than those without the defects.

"During prehistory, the stresses of infectious disease, poor nutrition and psychological trauma were likely extreme. The teeth show the impact," Armelagos says.

Until now, teeth have not been analyzed using the Barker hypothesis, which has mainly been supported by a correlation between birth weight in modern-day, high-income populations and ailments like diabetes and heart disease.

"The prehistoric data suggests that this type of dental evidence could be applied in modern populations, to give new insights into the scope of the Barker hypothesis," Armelagos says. "Bioarcheology is yielding lessons that are still relevant today in the many parts of the world in which infectious diseases and under-nutrition are major killers."

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