They might be only 140 characters long, but the mood swings captured in those tiny “tweets” can predict the movement of the stock market, says a new study. Measuring Twitter’s “calmness score” can predict how the Dow Jones Industrial Average will change three days later – with 86.7 percent accuracy.

“We were pretty astonished that this actually worked,” Johan Bollen, a social computational scientist from Indiana University, Bloomington, told Wired Magazine.

Bollen and a graduate student stumbled on what Wired calls a “computational crystal ball” while analyzing Twitter feeds for mood data. Bollen’s original goal was to build a nuanced barometer of America’s mood (he found that the West Coast is happier than the East coast, to the surprise of no one).

To that end, the researchers beefed up a standard psychological test called the Profile of Mood States, and applied the test as if Twitter were a patient in a psych ward, analyzing 9.8 million tweets from 2.7 million tweeters between February and December, 2008. The test picks out emotionally-charged words and adds each word’s score to one of six dimensions: calmness, alertness, sureness, activity, kindness and happiness.

The method was working smoothly in test runs. Then, just for kicks, they compared the national mood to the Dow Jones Industrial Average. They found that calmness lined up astonishingly well with the rises and falls of the stock market – but three or four days in advance? No one knows why. Many tweets come from teenagers who are unlikely to play the stock market. Still, factoring in tweeted emotions made a prediction algorithm 13.4 percent more accurate.

But it’s probably too early to drop out of school and invest everything based on Bollen’s test: these results only cover 11 months in 2008. Better finish that degree in economics, just to be safe.

– Emily Goyins

New research from UC Davis shows that particle size is much more important to chemical reactivity than previously thought. Understanding the differences between how large and small particles behave will have a wide array of applications, from cleaning up environmental pollutants and crumbling infrastructure to the biology of bacteria and the origins of life.

The research into particle size was led by Alexandra Navrotsky, professor of ceramic, ?earth and environmental materials chemistry at UC Davis. Navrotsky is also the director of the Nanomaterials in the Environment, Agriculture and Technology program on campus. Navrotsky studied the energy changes involved in oxidation and reduction reactions – a pair of reactions responsible for the transfer of electrons in compounds.

“Oxidation and reduction reactions are the energy source for most chemistry in nature,” she said.

Metals like iron, manganese, cobalt and nickel combine with different numbers of oxygen atoms. The resulting compounds form crystals with different “oxidation states” and thus, different properties. Metals occupy the lowest oxidation states and rock salt oxides occupy the highest.

Navrotsky and her team made very precise measurements of the energy changes resulting from changing from one oxidation state to another, using the data to make two major discoveries on the relationship between particle size and their behavior in oxidation and reduction reactions.

First, the properties of oxidation vary dramatically with particle size. Oxidation and reduction reactions take place under certain conditions of temperature and pressure, with a certain energy cost associated with starting the reaction.

“If you ask in what conditions – temperature, pressure and such – these compounds will oxidize, they will oxidize differently depending on their size,” Navrotsky said.

Second, the research team found that in general very small particles were formed with a lower energy cost for a given metal when the compound was in an intermediate structure called a spinel than compared with other states. Crystals that are in their spinel form have the lowest surface energy, which allows smaller particles to form, Navrotsky said.

Because metal oxides are used so widely in both industry and nature, the findings have a great many applications.

The process of rusting on crumbling infrastructure is also caused by oxidation-reduction reactions. As metal structures like bridges age, they are exposed to oxygen. The oxidation process causes rust and damages the integrity of metal structures. Navrotsky’s findings help to explain how exactly these processes occur and eventually how to help save the structures.

Metal oxides are also very important in biology. Bacteria that grow in anaerobic environments, such as underground, must get the oxygen essential for respiration from the oxidation-reduction reactions of metal oxides, Navrotsky said.

Early life on Earth had very limited access to oxygen as the atmospheric oxygen levels were much lower than they are today, so understanding how the metal oxides react differently depending on their size can help explain how life in different conditions were still able to get energy from the metal oxides around them.

“The authors are to be congratulated on demonstrating that the redox properties of metal oxide nanoparticles are dramatically different than their larger counterparts,” said Israel Wachs, professor of chemical engineering at Lehigh University in Pennsylvania. “This paper is a watershed contribution to metal oxide nanotechnology and is destined to become a classic publication.”

In 2009, Navrotsky was awarded the Mineralogical Society of America (MSA) Roebling Medal. The Roebling Medal is the highest award of the MSA for “outstanding original research in mineralogy.” The award was presented by Nancy Ross, the president of MSA.

“[Navrotsky’s] research is truly interdisciplinary and has successfully bridged many scientific divides, and that has enriched all of them,” she said.

Navrotsky’s co-authors on the study were graduate students Chengcheng Ma, Nancy Birkner and postdoctoral researcher Kristina Lilova. The work was supported by grants from the U.S. Department of Energy.

AMY STEWART can be reached at science@theaggie.org.

A few years ago, science writer Jonah Lehrer stood in a grocery store cereal aisle, paralyzed. There were too many options: honey-nut Cheerios, regular Cheerios, multigrain Cheerios. The decision-making process was overwhelming – so Lehrer wrote a book about it.

Lehrer is the author of How We Decide, a book about neuroscience and decision-making. He will be speaking at the Mondavi Center tonight at 8 p.m.

In an interview with The Aggie, Lehrer said he wrote How We Decide because he is a pathologically indecisive person.

“I would have mild panic-attacks trying to buy toothpaste,” he said

In a season of multiple-choice midterms, the stress of decision-making is a familiar feeling for students. Lehrer explained that the problem comes from the actual structure of our brains.

The human brain has an extremely evolved prefrontal cortex. The prefrontal cortex is the area of the brain credited for giving humans rational thought. It’s the reason we make lists of pros and cons. It’s also the reason our skulls look different from chimpanzees’.

“When monkeys looks at humans they’re like ‘Man, they’ve got really weird foreheads,'” Lehrer said.

To make a decision, the prefrontal cortex fires away, trying to control the more emotional, fearful part of the brain. The conflict between reason and emotions is why decisions are so agonizing. When you get on an airplane, your rational brain will remind you of the statistically low risk of a crash, but your pesky emotional brain flash back to the plane-crash scene in “Lost.”

“Plato compared [emotions] to wild horses inside the mind,” Lehrer said.

Traditionally, psychologists like Freud wanted patients to control their emotions. But Lehrer said that opinion has changed over time. “Research strongly suggests that we should actually trust our emotions,” he said.

The emotional brain flashes back to past events and gives guidance for the future. If you survived the last plane flight, your emotional brain will be happier about flying next time. Gaining experience in a field helps the entire brain make sturdier decisions.

“When you compare a chess grand-master to a chess novice, the grand-master is actually thinking less,” said Lehrer. “His emotions do all his work for him.”

While experience plays a big part in decision-making, anatomical changes in brain function are important, too. Thanks to aging, a college student’s brain and a college professor’s brain might come to very different conclusions.

Lehrer said the prefrontal cortex (rational brain) is the last area to fully develop. While teenagers wait for their prefrontal cortexes to kick-in, hormones race through their limbic systems, the parts of the brain that control emotions and behavior.

“They don’t have the rational muscle, so to speak, to keep these emotions in check,” Lehrer said.

Hence the college freshman who decides to go car-surfing.

But mature adults aren’t perfect either.

“Sadly, as we age, the prefrontal cortex is the first brain area to sort of fade away,” said Lehrer. “It loses density starting about age 55.”

When it comes to picking a new box of Cheerios, Lehrer calls himself a “work in progress,” but he does have advice for other indecisive folks: chill out.

“Thinking too much is a real problem,” he said.

MADELINE McCURRY-SCHMIDT can be reached at science @theaggie.org.

We nod our heads and promise to be healthy and safe but on the inside, we laugh at the silliness of the advice the doctor is reciting to us off his little clipboard. Exiting the cold, sterile world of the doctor’s office and re-entering the world of stressful academics, fast food, fist bumps and keg stands is a sure way to wipe any memory of the advice that boring doctor gave you.

Whenever I’m at the doctor’s office, I’m rushed through some quick coughs and head turns, and then rushed out after being reminded about my co-pay.

While I was writing a news article last week about men’s health at UC Davis, it dawned on me that the reason why I didn’t like doctors wasn’t because of the dreary atmosphere, but because my doctor has absolutely no idea who I am. Sure, he remembers my name, remembers what I looked like five years ago, remembers to ask how school is going and chuckles when I tell him I don’t blaze that often. Besides the rehearsed banter, I am just a series of statistics, charts and dosages.

What we need are doctors who know who we are; doctors who know about our lives, what sports we play, family histories, our social lifestyles, etc. This kind of care will not only help doctors make better decisions about how to treat current conditions, but will also help doctors spot potential future problems, and plan for them now.

Obviously experts have thought of this predicament as well. And, like a deus ex machina, the Men’s Health Program was born into the UC Davis Health System. According to their press release, they specialize in nearly everything I believed my primary care physician lacked. Every patient in the new program undergoes a thorough medical history and lifestyle questionnaire to improve the level of care he is receiving. Not only do the doctors here want medical history, they also want to know how you live your life: do you play sports?  Which ones?  Do you drink? Do you smoke?  Weed?  Casual sexual encounters?  With strippers? In Europe?

They want to know everything. Every detail you tell them is just one more weapon in the arsenal of knowledge the doctors will unleash upon your maladies.

Since nearly all men’s health programs I have heard of cater to older men, I figured the same for this one.

I called Alan Shindel, a urologist in the UC Davis Health System, and asked him some questions about the program, jokingly asking how far into their AARP membership men should be before signing up for the program. His answer surprised me.

“No man is not a candidate,” he said. “Men live shorter lives than women. Good medical advice early on can keep you healthy and sexually active into old age.”  

Well, hot damn! Where do I sign up?

One of Shindel’s co-workers, James Kiley, an internal medicine physician, summed up the predicament.

“Men tend to ignore health problems until it’s too late,” he said. Getting good medical care can help men live the lives they want to live.”  

My suspicions about private care physicians giving their patients very little time were confirmed when Shindel informed me that the average visit time with a private care physician is only about 15 minutes.

“There is little or no time for preventative maintenance,” he said.

That is exactly the kind of problem that the Men’s Health Program seeks to remedy. Right from the start, the program is intended to make you at ease.

“The program has been designed to create a place where men can feel comfortable, where they can discuss issues about their health that can potentially have long-term ramifications for their longevity and quality of life,” said Shindel. “The goal is for them to be able to stay active and healthy well into old age.”

This program sounds pretty amazing, and it’s all happening right here at UC Davis. You don’t even need to be a current UC Davis patient to sign up, and even better, visits are covered by most insurance plans.

So, if you ever want to shed some unwanted poundage before beach season, they can help with that. If you have a hernia from lifting your girlfriend’s five suitcases in and out of the car for a two-day vacation, the doctors can help with that, too. And if you ever have impaired memory and a strange rash from that steamy night at the Best Western with a goddess named Strawberry Daiquiri, they can probably help with that as well.

You can make appointments through their website, ucdmc.ucdavis.edu/menshealth or call (800) 4-UCDAVIS (482-3248).

HUDSON LOFCHIE can be reached at science@theaggie.org.

A new study by Stephen Kowalczykowski, a professor of microbiology at UC Davis, shows how DNA is separated like a magician’s trick with interlocking rings. On a daily basis radiation, chemicals and normal cellular processes constantly damage DNA. When chromosomes repair themselves they become interlocked.

Kowalczykowski worked with yeast in a test tube, studying the DNA repair system. He found that a complex of proteins called Sgs1, Top3 and Rmi1 open the double-stranded DNA of one chromosome to allow the other one to pass through.

“This protein complex does what magicians do,” Kowalczykowski said of the process.

When damaged DNA goes unrepaired, the damage can lead to cancer or birth defects. The so-called “breast cancer gene” BRCA2 can increase the risk of cancer as a result of a mutation that prevents proper DNA repair.

When damage only affects one strand out of a double-stranded chromosome, the other strand can simply serve as a template for repair. The process becomes more complicated when the damage affects both strands of a chromosome. In that case, one strand is stripped back so that the matching chromosome can attach itself to the section that is damaged. The matching chromosome is partially unwound, and each strand can now serve as a template: one for its own chromosome, the other for its matching damaged pair.

The chromosomes are now both intact but still attached at two points called “Holliday junctions.” In order to separate, one ring has to pass through the other like the magician’s rings.

Kowalczykowski showed how the Sgs1/Top3/Rmi1 complex of proteins attaches to the Holliday junctions and unwinds the section of DNA of one chromosome. The other chromosome can now pass through the gap and the two are cleanly separated.

Kowalczykowski’s recent research also showed that the Sgs1/Top3/Rmi1 complex of proteins also cleans the damaged section in order to leave a single strand of DNA. This is the first step of DNA repair, essential in order for the damaged DNA to attach to an intact length of DNA on another chromosome.

Properly repairing damaged DNA is what keeps cells from becoming diseased or even cancerous. The protein Sgs1 appears to be the yeast equivalent of the human protein tied to an illness called Bloom’s syndrome, Kowalczykowski said.

According to The Bloom’s Syndrome Foundation, patients diagnosed with Bloom’s syndrome have high risks of cancer, sun sensitive lesions to the face, chronic ear and lung infections and a form of diabetes similar to adult onset diabetes but arising much earlier in life. Patients have a defective form of the protein that keeps their DNA from being unwound and properly repaired after damage occurs.

Though they have been hypothesized to be present for 26 years, Holliday junctions have only been definitively shown to exist in mitotically dividing cells – cells that make exact copies of themselves – a few months ago by Neil Hunter, associate professor of microbiology at UC Davis and senior author of a paper on Holliday junctions in the April 8 issue of Nature.

Crossovers and Holliday junctions happen frequently in the process of meiosis, the process during which a cell divides to create four daughter cells which each have half of the DNA of the original. However, Holliday junctions are fairly rare in cell division.

“It makes sense that the double-Holliday junction pathway is a minor pathway of break repair in mitotically dividing cells because it is more likely to result in a crossover, and crossovers can cause the types of genetic changes that lead to cancer,” Hunter said.

AMY STEWART can be reached at science@theaggie.org