Is that a left-handed complement, or are you just happy to see me?
The mysteries of lefthandedness
In pursuing the left-right riddle, scientists are unlocking secrets of the brain, genetics and human diversity.
By Faye Flam
Inquirer Staff Writer
Plato and Aristotle puzzled over lefthanders, as did Charles Darwin. What determines "handedness"? Why are only 10 percent of us lefthanded, and why did the ratio seem to change over the last century? Are lefties somehow different - less healthy, more creative?
With brain scanning and the latest genetic technology, scientists are finally starting to crack the mysteries. Lefthanders really are special, and the ways they differ are yielding insight into human diversity - especially how one person's brain differs from another's.
Searches for a lefthanded gene, meanwhile, are untangling the roles of nature and nurture in shaping our behavior, and revealing ever more subtle ways that DNA can influence but not determine who we are.
"Its a quirky phenomenon of humans, and people ask why it's relevant," says research geneticist Clyde Francks of Oxford University. "But this is taking us into a fundamental feature of the human brain."
"Lefthandedness is connected to a lot of neurodevelopmental disorders," says Daniel Geschwind, a UCLA expert in what is known as neurobehavioral genetics. People with autism and schizophrenia are more likely to be lefthanded, he says. "But with that risk, there is also gain."
Look at MIT professors or musicians or architects, he suggests, and you'll see a slightly higher percentage of lefthanders than in the general population. Neuroscientists are beginning to figure out why.
The brains of lefthanded people develop more freely in utero, they say, allowing the organization to stray more from the standard design.
In most people, experts say, the left hemisphere of the brain specializes in tasks that are performed in sequence, such as reading and speaking; the right does more holistic processing, like that needed for visual perception. Most people have a dominant left hemisphere, and since each hemisphere controls the opposite side of the body, most of the population is righthanded.
For years, many psychologists assumed that lefties' brains were reversed, with language capacity concentrated in the right side of the organ. Subsequent work shows that is sometimes the case - but not always.
A large body of research shows the majority of righthanders follow the typical pattern, using the left hemisphere for language. Lefthanders' brains appear less predictable: About half have language abilities concentrated in the left, 10 percent in the right, and 40 percent make use of various regions on both sides.
Many animals are right- or left-pawed, or -footed or -flippered. Mice, for example, will consistently use either the right or left paw to press a lever. Unlike humans, however, most species are divided 50-50.
"Years ago geneticists tried to breed left- and righthanded mice," says Chris Walsh, a neurologist at Harvard Medical School and the Howard Hughes Medical Institute. The offspring were still evenly divided.
In humans, handedness runs in families, though not in an easily predictable way. Lefthanders are about twice as likely as righties to produce lefthanded children, but most of their offspring will still be righthanded.
In the 1980s, psychologist Marian Annett of the University of Leicester in the U.K. came up with a mechanism by which a single gene could produce such a pattern. Genes often come in two or more forms, called alleles, and she suggested that one form might predispose people to righthandedness while another, less-common, form leaves it up to chance.
Since we get two copies of each gene - one from each parent - Annett calculated that even two of the less-common form would give you no more than a 50-50 chance of coming out lefthanded.
A few years ago, UCLA's Geschwind scanned the brains of identical twins, hoping to understand the connection between handedness, heredity and brain structure. He found that pairs of righthanded twins tended to share a more asymmetrical brain structure than did lefthanded pairs or mixed sets.
The finding backed the idea that genes either drive the developing brain toward righthandedness or leave it to chance.
No single righthandedness gene has turned up despite many efforts to find it. Three months ago, however, a team led by Oxford's Francks discovered one that may at least play a role. They found that lefthanders tend to share a variant of the gene they named LRRTM1, but it appears to influence handedness only if it is inherited from the father. (Genes whose dominance is contingent upon which parent contributes them make up about 1 percent of the total in humans.)
In either form, this gene is active in the developing brain. "It influences the way different regions wire up and find connections," Francks says. Its effect on determining handedness is small, and the geneticist believes several yet-to-be discovered genes are also involved.
Environmental factors - stigma, social pressure, possibly hormones - could nudge people one way or the other as well.
Other scientists are examining how LRRTM1 and other genes might tie lefthandedness loosely with all sorts of characteristics. Various studies have found weak but statistically significant associations between lefthandedness and schizophrenia, autism and even homosexuality.
Psychologist Ronald Yeo of the University of New Mexico thinks the common link is a kind of flexibility known as developmental instability. Roughly, this describes the tendency to get off track during development, he says, freeing some brains to vary from the majority design, with each component in its place.
That may allow for novel ways of arranging the brain. Perhaps only an unusual configuration can produce an artistic and scientific genius like Leonardo da Vinci, who was reportedly both lefthanded and gay.
Lefthandedness studies, Yeo says, "have proven to be an avenue into understanding more general issues in how human beings develop and where variation comes from." In doing that, they sometimes overturn long-held beliefs.
Yeo reanalyzed a study that relied on death records to show that lefthanders died an average of seven years younger than righthanders but found that its conclusions were based on the incorrect assumption that the percentage of lefthanders has remained steady over time.
A few scientists say their colleagues are looking at the mystery of handedness from the wrong perspective.
University of Toledo psychologist Stephen Christman was trying to connect handedness with preference for types of musical instruments when he made an unexpected finding: people who were very strongly right- or lefthanded preferred keyboards and drums, while those who were more ambidextrous gravitated toward strings.
"I realized that maybe what's important is not left or right but strongly one-handed or mixed," he says.
There is some evidence, he says, that mixed-handers have a wider connecting pathway - called the corpus callosum - between the right and left hemispheres. Having a wider connection seems to make it harder to do more than one thing at a time - playing a different rhythm with each hand, for example.
Christman has found that strong right- or lefthanders, on the other hand, are more likely to hold to set beliefs, such as creationism. He speculates that communication between hemispheres helps people revise beliefs.
None of this suggests mixed-, right- or lefthanders have a corner on creativity or genius. Researching an essay on the lefty guitarist Jimi Hendrix, who famously played a righthanded guitar upside down, Christman made a shocking discovery: the much-photographed Hendrix held a pen with his right hand.
It makes sense, says Christman, himself a lefthanded guitarist, if you consider that in "righthanded" guitars, the left-hand job of working the frets has grown increasingly difficult as both styles and design have evolved.
So why not see how it works the other way around?
The article didn’t indicate if researchers were found in a purple haze or if manic depression really is a frustrated mess.
Nothing to see here. Move along.
Arizona nuclear plant sealed off but not in danger
By David Schwartz
PHOENIX (Reuters) - The Palo Verde Nuclear power plant, the largest in the United States, was sealed off on Friday after security guards noticed a suspicious item in a worker's car, said the plant's operator, Arizona Public Service.
"There is no threat to the plant," said Jim McDonald, APS spokesman, who did not say what the item was.
McDonald said the public was not in danger.
The plant, which has three nuclear reactors and is located about 50 miles west of Phoenix, continued to operate, APS said.
The worker was a contract worker, not a regular employee of APS, which operates Palo Verde for its seven owners, said Damon Gross of APS.
Sealing off the plant caused a stir among local media in Arizona, but McDonald said the event "was not a big deal."
Victor Dricks, spokesman for the U.S. Nuclear Regulatory Commission, said the NRC was "monitoring the response of the operator" but did not see any threat of danger to the public.
Two of the three reactors at Palo Verde were not in operation on Friday morning. One is in a refueling outage that will continue until the second half of December, and another was to return to the power grid as early as later today, an APS spokeswoman said. The third reactor is fully operating, she said.
With a combined electricity production capacity of about 3,900 megawatts, the three reactors can make enough electricity to serve between 1.5 million to 2 million homes mainly in Arizona, California, New Mexico, and Texas.
Homer Simpson is everywhere.
Well if they’re not standing or sitting, what’s left?
Scientists Discover New Way To Make Water
ScienceDaily (Nov. 1, 2007) — In a familiar high-school chemistry demonstration, an instructor first uses electricity to split liquid water into its constituent gases, hydrogen and oxygen. Then, by combining the two gases and igniting them with a spark, the instructor changes the gases back into water with a loud pop.
Scientists at the University of Illinois have discovered a new way to make water, and without the pop. Not only can they make water from unlikely starting materials, such as alcohols, their work could also lead to better catalysts and less expensive fuel cells.
"We found that unconventional metal hydrides can be used for a chemical process called oxygen reduction, which is an essential part of the process of making water," said Zachariah Heiden, a doctoral student and lead author of a paper accepted for publication in the Journal of the American Chemical Society, and posted on its Web site.
A water molecule (formally known as dihydrogen monoxide) is composed of two hydrogen atoms and one oxygen atom. But you can't simply take two hydrogen atoms and stick them onto an oxygen atom. The actual reaction to make water is a bit more complicated: 2H2 + O2 = 2H2O + Energy.
In English, the equation says: To produce two molecules of water (H2O), two molecules of diatomic hydrogen (H2) must be combined with one molecule of diatomic oxygen (O2). Energy will be released in the process.
"This reaction (2H2 + O2 = 2H2O + Energy) has been known for two centuries, but until now no one has made it work in a homogeneous solution," said Thomas Rauchfuss, a U. of I. professor of chemistry and the paper's corresponding author.
The well-known reaction also describes what happens inside a hydrogen fuel cell.
In a typical fuel cell, the diatomic hydrogen gas enters one side of the cell, diatomic oxygen gas enters the other side. The hydrogen molecules lose their electrons and become positively charged through a process called oxidation, while the oxygen molecules gain four electrons and become negatively charged through a process called reduction. The negatively charged oxygen ions combine with positively charged hydrogen ions to form water and release electrical energy.
The "difficult side" of the fuel cell is the oxygen reduction reaction, not the hydrogen oxidation reaction, Rauchfuss said. "We found, however, that new catalysts for oxygen reduction could also lead to new chemical means for hydrogen oxidation."
Rauchfuss and Heiden recently investigated a relatively new generation of transfer hydrogenation catalysts for use as unconventional metal hydrides for oxygen reduction.
In their JACS paper, the researchers focus exclusively on the oxidative reactivity of iridium-based transfer hydogenation catalysts in a homogenous, non-aqueous solution. They found the iridium complex effects both the oxidation of alcohols, and the reduction of the oxygen.
"Most compounds react with either hydrogen or oxygen, but this catalyst reacts with both," Heiden said. "It reacts with hydrogen to form a hydride, and then reacts with oxygen to make water; and it does this in a homogeneous, non-aqueous solvent."
The new catalysts could lead to eventual development of more efficient hydrogen fuel cells, substantially lowering their cost, Heiden said.
The work was funded by the U.S. Department of Energy.
Headline of the day
Disco-dancing dentist sued for drilling disaster
This just in—depressed people don’t feel like doing much.
Looking Into The Future: Can Your Perspective Influence Your Motivation?
ScienceDaily (Nov. 1, 2007) — Students, athletes and performing artists are often advised to imagine themselves performing successfully. That strategy is believed to motivate them for future exams, games, and shows. But is that motivation influenced by what perspective they take when imagining their performance?
The three studies explored in the article looked at two ways to visualize future performances -- first person (watching oneself through one's own eyes) and third person (watching oneself from the perspective of another person).
The authors, Noelia A. Vasquez, at York University (Canada) and Roger Buehler, at Wilfrid Laurier University (Canada), found that the third person perspective resulted in greater motivation to succeed at the task, especially when people imagined themselves performing well. The increased third person perspective appears to assign greater meaning to the task.
"Mental imagery is commonly used as a preparation strategy in a wide range of performance domains (school, sports, performing arts, public speaking, licensure exams -- as well less 'institutionalized' future performances, such as bringing up a difficult issue with a boss, or resisting temptations such as food or cigarettes)," commented the authors. "These studies suggest that if someone needs a motivational boost to prepare, they may be well advised to envision themselves from the perspective of their audience."
The article, "Seeing Future Success: Does Imagery Perspective Influence Achievement Motivation?" was recently published in the October issue of Personality and Social Psychology Bulletin, an official publication of The Society for Personality and Social Psychology.
"if someone needs a motivational boost to prepare, they may be well advised to envision themselves from the perspective of their audience." Really. How about if they are convinced their audience wants them to fail? And has wanted them to fail, just like everyone else, ever since 5th grade...but that's another story.
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