Physics Buzz

Graduate School Burnout Quantified

2012-05-17T16:30:00.000-04:00

For most graduate students in physics, a research focused career ranks more attractive than teaching, government work, or science outreach and writing. Most PhD physicists, however, will never attain a tenure-track position at a university. Upon entering graduate school, many students realize that the odds are against them, but they push forward regardless.

Students may not realize how their career perceptions will evolve throughout graduate school, however. A study published earlier this month has revealed that research careers become less attractive to graduate students as they progress through school.

This image shows the relative attractiveness of different careers for biology, chemistry and physics graduate students. Positive percentages represent the proportion of students who found a career more appealing over time, and negative percentages represent the proportion of students who found a career less attractive over time. Image Courtesy Henry Sauermann/Micheal Roach/PLOS One.

Surveying thousands of graduate students in biology, chemistry and physics, study authors Henry Sauermann and Michael Roach tracked career perceptions for five different levels of graduate students:

Those who have not yet passed a qualifying exam.
Students currently working on dissertation research.
Students working on non-dissertation research (e.g., as a research assistant).
Those who intend to begin actively looking for a job or post-doc position within the next year.
Students who are actively looking for a job or a post-doc position.

Moving from one to five, research careers became increasingly unattractive. In physics, the number of students who rated a research career as either "unattractive" or "extremely unattractive" doubled from 7 percent for early stage students to 14 percent of late stage students. Meanwhile, the percentage of physics students who ranked a research career as high as possible dropped from 60 percent to 53 percent.

A significant portion of graduate students are turned off by an academic career over time. But most students steadfastly pursue research careers despite the dearth of permanent positions. According to the study authors, this may be because advisers rarely counsel students on careers outside of academia.

The percentage of students who felt that their department encouraged or discouraged certain career paths. Image Courtesy Henry Sauermann/Micheal Roach/PLOS One.

Advisers don't actively discourage certain careers much more than others, at least in the minds of students. Instead, they don't discuss "alternative" careers with students, probably leading to the large neutral perception for careers outside of research. This may be because advisers rarely have extensive experience outside of academia; they can't give students reliable advice about these careers.

The authors of the study noted that universities should consider being more upfront about career prospects in research before admitting students. While this may lead to fewer students enrolling in graduate school, it will likely lead to fewer disillusioned students in the future.

Attending graduate school is a huge decision, and students should be well-informed before they take the plunge. We should give the students facts about careers after graduate school, but they ultimately have to make these life decisions themselves.

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Mayans End the World but Egyptians Give Us Data

2012-05-16T17:41:00.001-04:00

The constellation Perseus and Algol, the Bright Star in the Gorgon's headJohannes Hevelius, Uranographia, 1690

As I think everyone must know by this point, the Mayans seem to have predicted the end of the world on December 21st, 2012. Its an interesting thing to think about but there don't seem to be many people convinced enough by the prediction to be running around crossing off everything on their bucket list. Though it might be a good excuse to finally try bull riding. However, another ancient society gave us something more than a doomsday prediction, they gave us an invaluable data point in unraveling the mystery of eclipsing binary stars and how their mass changes over long periods of time.

An eclipsing binary system is made up to two stars that rotate around each other. On earth, it looks like any other star, but it twinkles in a very different, and periodic way. One star in the system is brighter than the other and when the dimmer star is the one in front we see the star as dark. But when the system turns and the brighter star is in front, we see it as brighter. Its possible to measure the period of rotation by watching how the system twinkles. The ancient Egyptians thought this dimming and brightening could predict if the day would be good or bad so they very meticulously recorded its period. Research by Jetsu et al suggests that the Egyptians not only measured the period of one of the most famous eclipsing binary systems, Algol, also called the Demon Star, but found it to be ever so slightly different than the system's period today. This ancient data point is extremely valuable to astronomers who are rarely able to take data on such a time scale.

The ancient Egyptians were amazing astronomers. They charted the movement of a vast number of stars, planets and moons and recorded them in intricate calendars. The best preserved of these is the Cairo Calendar dated to 1271-1163 B.C. Archeologist working with astronomers were able to determine which heavenly bodies' movements were being cataloged. One period was giving them all a bit of trouble. It was clear that something bright and visible to the naked eye was changing with a period of 2.85 days but there was nothing in modern day astronomy that had that as its period. However, Algol came close with a period of 2.867 days. That may not seem like a large difference, but if astronomers today and those of 3000 years ago were indeed measuring the same thing, the period shouldn't differ by even this small amount. The Egyptians had proven themselves to be much better observers than that.

Algol, better known as the Demon Star, appears in the constellation Perseus as the eye of the Medusa's head. Though on earth it looks like a star that gets brighter and dimmer with a period of 2.867 days, it is actually two stars rotating around each other with their orbit affected by a distant third star. The more massive Algol A is about 4.5 times more massive than Algol B and 2 times more massive than the very distant Algol C.

In these type of systems it has been theorized that "mass transfer" may occur. The mass of one star is transferred to the other and consequently the period of rotation is changed. But the mass isn't transferred quickly. Since this system was first measured in 1783 there hasn't been enough mass transfer to measurably change the period. But, over 3000 years the stars' masses may have changed enough to notice a difference. The discrepancy between the Egyptian's data and modern data is just the right amount to be explained by mass transfer. Without this ancient data, it wouldn't be possible to measure this. Though only a difference of 25 min over 3000 years this new period data point, found by archeologists and explained by astronomers adds a new level of understanding to eclipsing binary star systems.

Kodak's Nuclear "Reactor" Explained

2012-05-15T16:35:00.000-04:00

Correction: This blog post originally stated that Kodak's nuclear device was a nuclear reactor as was widely reported. This can be misleading. The device increased the output of neutrons from a radioactive source, but there was not enough material to initiate a chain reaction. The device was used in a very similar way to many research reactors found on university campuses. The post has been edited to reflect this.

This week, the Internet has been buzzing with news that Kodak had a nuclear facility housed in a basement at its Rochester, NY industrial park for over thirty years. Until 2007, Kodak used the device to check for impurities in samples, but the device wasn't widely known until the local Democrat and Chronicle newspaper ran an article late last week. Many have questioned why the company known for its photography products would need a nuclear device, and some alarmist articles have surfaced.

Gizmodo, for instance, began their article with extreme hyperbole while noting Kodak's recent bankruptcy:

"Kodak may be going under, but apparently they could have started their own nuclear war if they wanted, just six years ago."

Actually, Kodak didn't even have enough nuclear fuel to develop a single warhead. Refrigerator-sized nuclear devices like the one found in Kodak's basement have key differences with nuclear reactors found at power plants, and Kodak certainly couldn't have ignited World War III alone. In fact, the device is very similar to research reactors that can be found on several university campuses, and they are operated under strict guidelines without any nefarious intentions.

Researchers working at Kodak wanted to detect very small impurities in chemicals and impurities, and Neutron Activation Analysis (NAA) proved to be one of the best techniques to find these impurities. During NAA, samples are bombarded with neutrons, and elemental isotopes from the sample will absorb a small fraction of these neutrons.

Many of these stable elemental isotopes will become radioactive after gaining a new neutron; consequently, they will emit gamma rays. With the right equipment, researchers can measure the precise energy levels of this radiation and narrow down which elements are in the sample.

"For some elements, this is an exquisitely sensitive test," said Ken Shultis, a nuclear engineer at Kansas State University who works on the university's nuclear research reactor. "To do this [test], you need a source of neutrons."

For Kodak, that source was an isotope of Californium, a radioactive element first synthesized in 1950 with a cyclotron at the University of California Berkeley. Californium-252, the element's most common isotope, was initially used at Kodak as a neutron source by itself.

"Californium-252 is a poor man's reactor," said Shultis.

While a sample of this isotope will shed neutrons by itself, Kodak wanted more neutrons to increase the sensitivity of their analyses. That's where a small nuclear facility could help. The researchers could either collect a larger sample of Californium or use uranium plates to multiply the neutron flow from the source they already had. They opted for the uranium route.

With 3.5 pounds of uranium on-site, Kodak had far less than the roughly 100 pounds needed to develop a weapon. Strict security precautions were still taken, nonetheless.

But the device Kodak had and research reactors at universities don't pose the same safety risks as bigger nuclear reactors at power plants. Power plants produce much more fission products, and they require much more extensive cooling systems, according to Shultis.

"It's inherently much safer. There's no chance of a meltdown in our research reactors," Shultis said.

Radioactive materials used at research reactors still pose potential risks, according to Shultis. Consequently, researchers take great care when dealing with their samples. If samples become too radioactive, for instance, they can be left in the reactor pool until they decay enough to be safe.

Reactors like the one at Kansas State University and the decommissioned instrument at Kodak must meet strict guidelines determined by federal regulators. I wonder if those regulators were surprised when a photography company approached them many years ago with plans to use highly enriched uranium. It certainly caught many people by surprise this week.

Top image of Idaho National Laboratory's Advanced Test Reactor courtesy of Argonne National Laboratory.

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Can NBA Timeouts Decide Games? Scientists Say No

2012-05-14T16:30:00.000-04:00

The NBA playoffs are in full swing, and eight teams have survived the first round of basketball. My home team, the Denver Nuggets, were booted from the playoffs last week after a game seven showdown against the LA Lakers (boo!), prompting faithful Nuggets fans to question what our team could have done differently.

Did we lose too many turnovers? Was there something our coach could have done? Is Kobe simply an unstoppable force?

Although no one can pin down a single reason for NBA game outcomes, physicists have ruled out one explanation: the "momentum changing" timeout.

Image courtesy CT Snow via Flickr.

Serguei Saavedra, a statistical physicist at Northwestern University, and his colleagues collected official scoring and timeout data from the NBA website. Because the NBA provided play-by-play recaps for all of the games, the researchers could compare scoring differentials before and after timeouts were called.

With data from 3,000 NBA games dating back to 2009, Saavedra and his team found no evidence that supposedly critical timeouts could lift trailing teams to victory. In fact, the statistical analysis revealed that teams with big leads racked up even more points after time outs were called.

The team analyzed three seasons for 30 different NBA teams, giving them a sample of 90 individual seasons. They found that 78 of these 90 seasons displayed no statistically significant correlation between timeouts and changes in scoring differential. There's a very good chance that randomly-timed timeouts could have led to the same scores.

To be fair, timeouts may be more important at different times in the game. Towards the end of the game, for instance, coaches will call a number of timeouts to take advantage of every remaining second on the clock. Did these fourth quarter timeouts help decide the winner?

No, say the researchers. Even after accounting for different quarters, there was still no significant correlation between timeouts and score changes. Furthermore, teams with higher payrolls weren't able to capitalized on timeouts any better than teams with lower payrolls.

One factor the team didn't analyze, however, was the relationship between coaches' salary and effective use of timeouts. I wonder if the millions of dollars teams spend on coaches translates into mid-game comebacks. Maybe the old whiteboard dotted with X's and O's -- a coach's go-to timeout tool -- isn't so effective after all.

You can read the research on the arXiv preprint server.
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Simulated Skiers Reveal Mountain Traffic Jams

2012-05-11T15:32:00.000-04:00

Researchers incorporate physics, psychology and computer science in an effort to reduce congestion on ski slopes.

Millions of skiers and snowboarders escape to the mountains every winter, but some everyday stresses -- like traffic jams -- are unavoidable even on the slopes. In plenty of time to prepare for next season, a team of Swiss researchers has combined GPS tracking data and a skier traffic simulation to help reduce collisions between skiers on the mountain.

Modeling skier traffic requires a twofold approach: the team had to replicate not only physical forces, such as gravity and friction, but also "social" forces, such as each skier's tendency to avoid another and the edges of the ski run.

When added together, all of these forces determined the paths that individual skiers took down the mountain. The researchers simulated thousands of skiers traveling down two slopes at a nearby resort to determine average speeds and densities.

"There are so many variables for any given run. Being able to model it is very difficult," said Pete Williams, a senior mountain planner at the design firm SE Group, who was not affiliated with the research.

To test their model, the team left the lab and hit the slopes. Thomas Holleczek, a graduate student in the wearable electronics group at the Swiss Federal Institute of Technology in Zurich and lead author of the research, handed out GPS-enabled phones to skiers at the local resort.

Compared to previous methods to track skier speed with video cameras, this approach was a breeze.
"You needed very expensive algorithms which detect the movement of skiers," Holleczek said. The new research was published this month in the journal Physical Review E.

Holleczek compared the GPS data with his simulation results and found that the computer model replicated behavior on the intermediate level run well. However, the simulation did not fully account for skiers' tendency to periodically stop and rest on the more advanced trail.

Nonetheless, insurance agents in Switzerland liked the idea of having such a model, said Holleczek. He believes that the model could help ski operators identify and fix congested areas, making resorts safer. Holleczek's research revealed unexpected bottlenecks on the two ski runs that could be missed by the untrained eye, and these areas could be widened to reduce congestion.

But not everyone is a believer. These bottlenecks typically arise in poorly planned resorts, and operators can avoid congestion problems during the design process. Furthermore, little research has been devoted to applying traffic models to sports, and ski operators are skeptical of their usefulness. Williams discovered this aversion when he approached his clients with a similar model years ago.
"We asked ski area owners and operators if they were interested," said Williams. "They said, 'Why would I do that? Once it's up and running, there's no need to model it.'"

Consequently, Williams avoids detailed modeling of skier behavior in his analyses. Inconsistent difficulty ratings for ski runs are typically more detrimental to safety than congested trails, he said. Ski operators still want to avoid congestion because it degrades the visitor experience.

Unlike Holleczek’s model, Williams’ analyses can't always account for the randomness of skier behavior that may lead to pulses of higher traffic, he admits. Although models like Holleczek's may start to account for these pulses, Williams added that it's extremely difficult to include every important variable, ranging from weather conditions to psychological tendencies.

Engineers and computer scientists were greeted with similar skepticism when they first developed computer simulations for vehicular traffic in the 1970s. Nowadays, however, urban planners and government agencies have increasingly seen the benefit of these models.

Models can never account for all of the randomness of human behavior, but robust simulations can still be useful, said Ahmed Abdel-Rahim, a civil engineer specializing in traffic modeling at the University of Idaho.

"These models have continuously been improved and validated with data," said Abdel-Rahim.
Increasingly, ski resorts have been tracking the data needed to validate Holleczek's simulations. The ski resort where Holleczek collected his GPS data is developing a mobile application for skiers to track their movements on the slopes. In the U.S., several resorts have incorporated data tracking directly into lift passes.

Holleczek hopes to account for more variables in his simulations in the future. With more data from ski resorts, he hopes to further improve his models and convince resort operators of their usefulness.

Brian Jacobsmeyer, Inside Science News Service

Liquid Levitation

2012-05-10T16:30:00.000-04:00

Splash water on a hot skillet, and it will evaporate very quickly. But if you heat it up a little bit more, you'll start to see some new physics: the water droplets will skitter across the surface without evaporating. Upon contact, a protective vapor forms between the water droplet and the skillet, allowing it to levitate across the surface with very little friction.

Called the Leidenfrost effect, this phenomenon occurs at temperatures much higher than a liquid's individual boiling point. Now, researchers have transferred the Leidenfrost effect from the kitchen to the lab. By controlling liquid oxygen droplets with magnets, scientists have uncovered some of the physics behind these dancing droplets.

Video courtesy of Keyvan Piroird, Baptiste Darbois Texier, Christophe Clanet and David Quéré.

Because oxygen's boiling point is so low (-183 degrees celcius), the team of French researchers were able to observe this effect at room temperature. Also, liquid oxygen is paramagnetic, so it will respond to magnetic fields. When the droplets passed close to magnets, they could slow down, speed up or change their shape depending upon the direction of the magnetic field relative to the droplet's velocity. All of this can be seen in the video above.

For the newer research, Keyvon Piroird, a physicist from ESPCI ParisTech, and his team looked at new ways of manipulating the drops.

For instance, the team was able to slingshot the drops around moving magnets, similar to gravity assists used to shoot spacecraft toward the outer planets of the solar system. When a spacecraft approaches a planet with the right velocity, it can whip around them and accelerate in a new direction. Although the spacecraft's velocity relative to the planet remains the same, its velocity relative to the Sun can change. This allows spacecraft to save fuel for longer journeys.

Similarly, the water droplets could be accelerated around a moving magnet. The moving magnetic field would shoot the liquid oxygen in a new direction and increase its speed. In the future, the team hopes to investigate how magnets could affect orbiting droplets, possibly causing them to rip apart.

Leidenfrost would be proud.

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I'm a Good Person so I Trust Facts

2012-05-09T20:52:00.001-04:00

Photo courtesy of Wikipedia

NPR is a great way to spend a commute and often they talk about some great, new research. Sometimes it is unpublished or questionable, but still gets you thinking. This morning NPR was talking about how when presented with facts that contradict strongly held opinions most people will hang on to their opinions in the face of solid facts. This has been seen specifically when people are interviewed about the president's ability to control gas prices. A majority of republicans say he can and a majority of democrats say he can't. However, if the peson polled was made to feel good about themselves they were more likely to listen to the facts and possibly changing their opinion. This is pretty impressive and an odd connection. If this is a true phenomenon it would apply to facts outside of just gas prices or politics in general. What would the effect be on controversial politicized science concepts or how we teach science in school? Is the key to teaching counterintuitive material or convincing a school board that intelligent design is not a science making everyone start the day by looking into a mirror and saying "I'm good enough, I'm smart enough, I occasionally don't cut people off in traffic and I am kind to small animals."

As I am sure everyone is aware, in many states there has been a push to "teach the controversy" by including intelligent design in science class. The fact of the matter is that there is no controversy. One idea is based on years of scientific discovery and one is based on the fact that people don't like what the science is saying. There is also the unfortunate use of the word "theory" which is easily misunderstood by the public. So lets say you go to a meeting of your conservative school board and wish to argue your case for removing intelligent design from the curriculum and making sure that evolution is taught exclusively. You could stand there with a long list of facts saying why one is a science and belongs in science class and one should have no place in schools. Will that really work? Hasn't this group dismissed those facts before? But what if the first thing to do when you walk into that room is have everyone talk about a time they felt good about themselves. Brendan Nyhan and Jason Reifler argue that doing so would make them more likely to see your point of view.

When people are presented with facts that oppose their currently held beliefs they experience cognitive dissonance and it doesn't feel so great. This research argues that if people are made to feel good about themselves before you make them feel bad by telling them they're wrong, it will end up balancing out and they will be more likely to listen to contradictory facts. Because science is fundamentally based on facts, this is some powerful stuff for those arguing for science policy to understand.

There is another way to use these interesting techniques, education. It is widely assumed that when someone is presented with facts in an educational setting they will 'see the light' so to speak and change their view. Nyhan and Reifler have seen that facts aren't always convincing enough. Could this idea of self-affirmation also be used in a classroom setting? This is very much outside the scope of the paper, but still an interesting thing to think about. Often times students are presented with ideas that are contrary to their long-held beliefs about the world. A great example of this is falling objects. If told that heavier objects fall at the same rate as lighter ones, students simply won't believe you. It falls to the teacher to create an experiment that successfully dispels this misconception and sometimes students still won't believe you. It can also be extremely difficult and sometimes impossible to come up with good experiments. So maybe, if teachers have their class write about times when they were really good kids before showing them that the world is very different from how they thought it was, they will be more likely to accept what they see.

Disclaimer: This research has not passed the peer review process and has not yet officially been published. However, I thought the ideas presented were interesting and applicable and decided to write about it anyway.

What is Science? Philosophy Has Answers (sort of)

2012-05-08T16:55:00.000-04:00

Homeopathy vs. modern medicine. Astrology vs. Astronomy. Intelligent design vs. evolutionary biology.

Debates between scientists and pseudoscience supporters have increasingly infiltrated the public domain. Intelligent design proponents want the theory to be taught as a science; homeopathy practitioners claim to cure illness with highly diluted ingredients despite contrary scientific findings; and astrologers make constellation-based predictions found in the back page of newspapers worldwide.

Most experts tend to agree on what areas constitute pseudoscience, such as the three listed above. But what criteria should we use to differentiate between science and pseudoscience or the broader category of non-science?

Called the demarcation problem, this question has kept philosophers and scientists busy for over a century. So what is science? What test can we apply to a theory to see if it's scientific? No one has unambiguously answered these questions, but philosophers of science have made some headway in the debate over the last 50 years.

One of the most influential thinkers on this topic was the 20th century philosopher Karl Popper. He thought that the defining characteristic of science was falsifiability -- the ability to generate hypotheses that could be proven false by observations or experiments. So why did Popper chose falsifiability as the distinguishing factor between science and non-science? That answer lies in his thoughts on the theories of two famous 20th century thinkers: Albert Einstein and Sigmund Freud.

Psychoanalysis vs. General Relativity

In Popper's mind, Freudian psychoanalysis was certainly not scientific. Because psychoanalysis tried to explain all of human behavior, Freud's theory never presented claims that could be proven wrong. The primary goal and supposed strength of Freud's enterprise made it unscientific, according to Popper.

Einstein, however, made some "risky" predictions with general relativity. For instance, special relativity predicted that starlight would bend around massive objects, a hypothesis that astronomer Arthur Eddington tested during a 1919 solar eclipse as seen in the image to the left. The observations agreed with the hypothesis, and Einstein's theory passed a test. This is science -- at least to Popper.

Popper certainly didn't think that tests like these proved the truth of a theory, however. Instead, he thought that risky predictions that passed a test, such as Einstein's light bending hypothesis, only corroborated scientific theories. He thought that we could never truly verify a scientific theory, so the aim of science is to constantly try to refute theories with risky tests.

But Popper's thoughts on the topic didn't settle the demarcation problem. For instance, some have argued that astrology can make some falsifiable claims (that turned out to be false), and Popper would have to classify it as a scientific theory, albeit false one.

In fact, his work influenced a great deal of philosophers who later disagreed with him. Perhaps the most famous contributor after Popper was Thomas Kuhn, a philosopher who coined the modern day usage of the word paradigm.

Paradigms and Revolutions

Kuhn was fascinated with scientific revolutions. Einstein's radical transformation of modern physics was one such example of a revolution. But this wasn't what science is all about, according to Kuhn. Instead, it's mostly about day-to-day problem solving.

Einstein disrupted the paradigm of physics, moving from a Newtonian set of assumptions to those set out by his theories of relativity. Now, scientists had a whole new set of tools. After Einstein, many scientists set out on a new cycle of what Kuhn called "normal science."

When conducting normal science, scientists accept a set of shared theoretical beliefs, such as the theories of relativity, and solve all of the remaining puzzles that fall under these beliefs. Scientists solve these puzzles, and pseudoscientists do not.

Kuhn's solution remains controversial, however. Some have argued that conventional pseudoscience, such as astrology, may fall under the broad category of a puzzle solving activity. Other philosophers have built upon Kuhn's and Popper's work, but the demarcation problem remains an open topic of debate in philosophy.

Now What?

Philosophers have tried to find an adequate solution to the demarcation problem for years. They've made a lot of progress, yet they still haven't nailed down definite criteria that can separate science from pseudoscience or non-science. So why bother?

As pseudoscience creeps into many people's everyday lives, being able to distinguish between scientifically-backed results and pseudoscientific claims has become increasingly important. In philosophy of science, there's been definite headway toward articulating this distinction.

When people are afraid or distrustful of science, scientists need to appeal to outside help to convince skeptics of science's usefulness. And that's where philosophers can help. Philosophers are somewhat removed from the science, and they can deliver some perspective on what science truly is.

Falsifiability and problem solving may be two elements that help to define science, but we likely need more criteria. We're part way there, though, and scientists can use the work of these philosophers to convince non-experts why certain theories have much more justification than others.

For a more thorough explanation of the demarcation problem, check out the Stanford Encyclopedia of Philosophy's articles on Kuhn, Popper, and pseudoscience.

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Statistical Analysis Hints at Voter Fraud in Russia

2012-05-07T17:05:00.000-04:00

Today, Vladimir Putin was inaugurated to his third term as the Russian President after a landslide victory in March elections. Putin has bounced between his roles as Prime Minister and President for 12 years, but many have accused Putin and his United Russia party of rigging elections in the past.

While voter fraud can be hard to detect, a group of researchers has carefully analyzed the official election data for clues and posted their analysis on the arXiv preprint server. The researchers found several questionable anomalies in the data that always seemed to support Putin and his party, casting doubt on the integrity of the recent elections.

Dmitry Kobak, an engineering graduate student at Imperial College in London, lead the team's analysis of government provided election data. The team found several major aberrations in data for the Presidential election held in March and the parliamentary election held late last year.

High Correlation Between Turnout and Results

In most fair elections, there is a slight correlation between turnout at polling stations and the percentage of voters who chose the winner. Russia's two recent elections, however, exhibited a distinct cluster of polling stations with voter turnout exceeding 95% and extremely high support for Putin and his politcal party's leaders.

Data for Putin's competitors, on the other hand, did not show this same correlation.

Fig. A United Russia's election result on the y-axis and voter turnout on the x-axis with red indicating high numbers of votes for UR. The graph shows a cluster of precincts with extremely high turnout (95 percent and up) and high support for Putin's party. Fig. E shows the same result for Putin's Presidential election. Both images courtesy Kobak et al. via arXiv.org.

Kobak and his colleagues traced the results to nine regions within Russia that yielded approximately 3.5 million votes for Putin. But aggregating data from a wide range of urban and rural areas with differing socio-economic statuses could have introduced this anomaly in the data.

To account for this potential explanation, the researchers broke the data down more narrowly, looking at the results for urban and rural areas separately. Independently, rural and urban areas had the same high correlation, and further analysis revealed that this cluster was an endemic feature of certain constituencies. These constituencies may have produced artificial election results, according to Kobak's group.

Votes Hovering around Round Numbers

In addition to the aforementioned correlation, the data reveal spikes in polling places that had round number percentages of votes in favor of Putin and his party. For instance, many constituencies reported that 65, 70, 75, or 80 percent of the vote favored Putin and United Russia. Non-round numbers, like 72 or 67, did not show similar spikes. Furthermore, Putin's competitors did not have similar spikes in support.

Most notably, a large number of votes came from precincts with 99.5 percent of the voters supporting United Russia. The authors of the research suggested that these factors may indicate votes were rigged to yield a previously determined threshold of votes. In other words, election officials wanted to win by a certain amount, and they may have fixed the vote to an acceptable winning percentage.

The amount of votes for United Russia and competing parties as a function of the percentage of voters supporting them. Notice the spikes in support around round numbers like 65, 70 and 75. Image courtesy Kobak et al. via arXiv.org.

Other Key Anomalies

The first two factors definitely hint at some sort of wrongdoing, but there's even more revealing messages hidden in the data, according to Kobak's team. There were significant differences between paper-based results and electronic results. Furthermore, several regions exhibited strangely uniform results across many of their polling stations.

Although this analysis does not conclusively prove the election was fair or not, it certainly raises several questions about the results. Russia has a long history of stifling dissent, and Putin's opponents have frequently accused him of unfair elections. Now, his opponents have one more piece of ammunition: statistics.

From left to right, the top two images are courtesy of www.kremlin.ru and Bogomolov.pl via Wikimedia Commons.

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Scientists on trial in Italy . . . again.

2012-05-04T15:44:00.000-04:00

Italian officials have put a group of seismologists on trial for failing to adequately warn the people of L’Aquila of a magnitude 6.3 earthquake that struck on April 6, 2009.

Seismologists who failed to warn of an earthquake that struck the town of L'Aquila, Italy on 6 April 2009 are on trial for manslaughter.Credit: RaBoe/Wikipedia

There is no question that the L’Aquila earthquake was a horrific event. It resulted in massive destruction and the deaths of 308 people. I completely understand the urge to find someone to blame for the tragic outcome of this terrible act of nature. But under no circumstances should scientists be prosecuted for holding or expressing scientific opinions, no matter how wrong they turn out to be.

There are, of course, complicating factors to consider in the trial. For one thing, the spokesperson for the group of seismologists, Bernardo De Bernardinis (deputy head of the Department of Civil Protection), is apparently completely unqualified when it comes to seismology. Shortly before the quake, De Bernardinis reassured the press by saying, “The scientific community tells me there is no danger because there is an ongoing discharge of energy.” Presumably, he meant that the series of small quakes that had been troubling the area actually reduced the risk of a really big event happening. The statement is at best gibberish that virtually no professional seismologist would agree with, but it apparently it was an attempt to convey the message that the risk of a dangerous quake was small.

A small chance is not the same and none, unfortunately, and the deadly quake hit L’Aquila one week after Bernardinis made his nonsensical attempt to reassure the citizenry.

Now, I know nothing about seismology. Nor do I really know much about the case against the seismologists. It's possible, for instance, that they realized the risk of a major earthquake was large, but decided to lie for some nefarious reason. (That would be both evil and amazing, considering that no one has ever predicted an earthquake with any real precision.) My main problem is with one particular witness for the prosecution: Lalliana Mualchin.

Mualchin claims that the Italian seismologists are using the wrong model to assess earthquake risk. And he may be right. But lots of scientists are wrong about lots of things. That's the very nature of science. We propose models, test them, discard the bad ones, and refine the good ones. Even the decent ones (think Newtonian mechanics and Lamarckian injeritance) are often found to be lacking and are improved or replaced with better ones (like Relativity and natural selection).

If there's some sort of Jaws scenario going on, with politicos and bureaucrats (and even crooked scientists), misusing or misrepresenting science for any reason whatsoever, then those people should be charged.

Mualchin's claims, however, are not that the seismologists lied. He's saying that their model isn't as good as his. This would be like putting Newton on trial because his theories fail to explain how a nuclear bomb works. That is, even if Mualchin's models are better, scientists using generally accepted science are not doing anything improper.

I suppose that if there's anywhere that scientists can be prosecuted for doing science, it's Italy. After all, that's where Galileo was when he was put under house arrest for suggesting the Earth isn't the center of the universe. I'm just glad the Italians only pull this sort of thing every 400 years or so.

May The 4th Be With You

2012-05-04T15:00:00.002-04:00

So today is apparently International Star Wars Day (May the 4th, "May the force...," get it?). It's an amazing work of science fiction that draws on science fact, myth and good old fashioned storytelling. Or at least the first two and half movies did. Because the Dark Lord himself, George Lucas, is master of all copyrights we can't really show you anything from the films without incurring the wrath of his dark forces. So instead, here's a picture of something in science that LOOKS like something in Star Wars; Saturn's moon Mimas totally looks like the Death Star.

"That's no space station, that a moon!"

Physics of the Hit: Football Concussions

2012-05-03T16:30:00.000-04:00

Earlier this week, Junior Seau, a former star linebacker for the San Diego Chargers, died of an apparent suicide. Some have speculated that a career of hard hits may have contributed to a string of high-profile suicides by former NFL athletes including Seau. Today, 100 former NFL players have filed a lawsuit against the NFL for failing "to take reasonable steps necessary to protect players from devastating head injuries."

For years, teams of researchers have tried to connect the various forces behind a tackle with the extent of head injuries. This research has led to a better understanding of what kinds of hits cause the most damage -- and what can be done to prevent brain injuries.

Image courtesy Keith Allison via Flickr.

"Traumatic brain injury [research] has been underappreciated for decades," D. Kacy Cullen, a biomedical engineer specializing in the biomechanics of neural injuries at the University of Pennsylvania, told Physics Central.

Recent publicity of head injuries in sports and the military has led to a greater appreciation of this field of research, Cullen added.

Cullen's lab has coupled analysis of sports impacts with animal models to better understand the health effects of repetitive minor injuries such as those accumulated throughout an NFL career. Repetitive hits may not lead to obvious signs of structural change in the brain, but they may affect how cells in the brain communicate.

"We're gaining a greater appreciation of some of the very subtle changes that are associated with minor injuries," said Cullen.

Direct hits to the head can cause serious injuries, and modern helmets have generally done a good job of absorbing impact forces that can fracture skulls. Repeated concussions throughout a career, however, may often stem from a different kind of impact.

Certain angles of impact can lead to abrupt rotational forces in the head. The resulting rotation of the head is one of the primary causes of closed head traumatic brain injury, according to Cullen. Rotations around different planes can lead to different biomechanical parameters and injuries varying in severity.

Despite research indicating the importance of these rotation, modern helmets don't absorb rotation well. Helmet standards aren't designed to dampen the blow of forces that cause rotation, and a breakthrough in helmets could come if they accounted for these forces, said Cullen.

Although there is room for improvement, researchers attempting to prevent injury have had difficulty adapting to changing playing styles. As more players lead with their helmet during a tackle, for instance, they become more vulnerable to injury.

"There's an arms race between better protection and evolving techniques," said Cullen.

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To keep up with Hyperspace, AKA Brian, you can follow him on Twitter.

Physics: The Greatest Show on Earth

2012-05-02T23:21:00.002-04:00

This past weekend PhysicsCentral, along with the American Association of Physics Teachers (AAPT), the Society of Physics Students (SPS), The Optical Society (OSA), the Acoustical Society of America (ASA) and the University of Maryland MRSEC teamed up to present 'Big Top Physics' at the second USA Science and Engineering Festival (USASEF, tired of the acronyms yet? So are we). Held Saturday and Sunday with a preview day on Friday, this event attracted over 100,000 people to the Washington DC convention center to interact with exhibits from every branch of science. This is the second time PhysicsCentral has participated in the event and we had a second amazing showing.

Last year in honor of LaserFest we created a 'Laser Haunted House' that drew such a crowed there was a 45 min wait to go through our exhibit. This year we wanted to again make it a themed booth and what better than the physics of the circus. There were stilts to demonstrate balance:

Photo by: Matt Payne

A tightrope of course:

Photo by: Matt Payne

Spinning Plates to show off the joys of angular momentum:

Photo by: Mike Lucibella

An amusing way for kids to play circus music:

Photo by: Mike Lucibella

And of course, the ever popular bed of nails:

The event went off with out a hitch in spite of the huge crowds and questionably stable tents. Hopefully next year will be even bigger and better. Time to start planning!

Is Philosophy Relevant to Physics?

2012-05-01T16:30:00.000-04:00

Over the past few months, a controversy has erupted between members of the fields of physics and philosophy. It all started in January when Lawrence Krauss, a well-known cosmologist and science writer, published his book titled A Universe from Nothing: Why There is Something Rather than Nothing. Krauss' book attempts to show how the universe could have come from "nothing," as implied by quantum field theory.

Significant hype accompanied the book. In the afterword for the book, noted atheist and biologist Richard Dawkins compares the book to Charles Darwin's most famous work:

"If On the Origin of Species was biology’s deadliest blow to supernaturalism, we may come to see A Universe from Nothing as the equivalent from cosmology. The title means exactly what it says. And what it says is devastating."

Several months after the book's publication, David Albert, a philosopher of science at Columbia University, wrote a scathing critique in the New York Times.

Quickly, the debate degenerated into personal attacks. In an interview with The Atlantic several weeks later, Krauss derided the "moronic philosophers that have written about my book."

He also said, "Philosophy is a field that, unfortunately, reminds me of that old Woody Allen joke, 'those that can't do, teach, and those that can't teach, teach gym.' And the worst part of philosophy is the philosophy of science."

He's wrong, and several famous physicists would agree that philosophy can play an important role in understanding scientific results.

In particular, Albert Einstein weighed in on the topic back in 1944 in response to a young physicist who was trying to incorporate philosophy into his modern physics course:

"I fully agree with you about the significance and educational value of methodology as well as history and philosophy of science. So many people today—and even professional scientists—seem to me like somebody who has seen thousands of trees but has never seen a forest. A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is—in my opinion—the mark of distinction between a mere artisan or specialist and a real seeker after truth."

Einstein sincerely believed that his interest in philosophy made him a better scientist. Using his philosophical background, Einstein took a step back, realized what was wrong with the current scientific paradigm, and built a revolutionary new theory of relativity.

Throughout the rest of the 20th century, there were several other notable physicist-philosophers. Niels Bohr and Werner Heisenberg, for instance, were credited with formulating what is now known as the Copenhagen interpretation of quantum mechanics. This interpretation has sparked much debate and added to the discussion of quantum mechanics' implications.

Having a background in philosophy -- or at least engaging in philosophical questions -- has helped past physicists advance their scientific work. It's important to note that many philosophers of physics have strong backgrounds in science, and many have doctorate degrees in physics. So Krauss' argument that most philosophical contributions have been made by physicists is somewhat misleading. Physicists made these contributions, but they did so as philosophers of science.

These icons were addressing questions that physics alone could not fully answer. Furthermore, several philosophers of science have made contributions that go beyond the realm of science. Thomas Kuhn, for instance, coined the contemporary usage of the word "paradigm" while discussing scientific revolutions.

In the future, I hope to share some of the big ideas in philosophy of science and their subsequent impact on the blog, so stay tuned!

For a thorough and thoughtful look at the specific argument between Krauss and Albert, see this post by Sean Carroll over at Cosmic Variance.

Podcasts and the Physics of Plant Roots

2012-04-30T09:40:00.003-04:00

This month on the Physics Buzz podcast I'm talking to two physicists who are both studying plant roots.

Last week on the podcast I talked to Cornell physics graduate student Jesse Silverberg about his work studying the way plant roots curl as they make their way through layers of soil. With the booming population of humans consuming more and more food, while taking up more and more space, we're going to need to understand how plants survive (or why they don't) in unusual environments.

Look out in the next week or two for the next podcast in this series, where I'll talk with Dr. Dawn Wendell, who is taking a lesson from plant roots and applying it to robots. Many plants live in granular materials, which can include sandy or rocky soils. Plant roots wind their way through these odd locations, looking for the path of least resistance, rather than trying to force their way straight down. Wendell says that robots and mechanical diggers that incorporate this principle of flexibility can save energy and go further than those that are rigid. These diggers might be trying to make their way through rubble at disaster areas, snow after an avalanche, or the sandy soil at the bottom of the ocean.

[Image courtesy of Jesse Silverberg and the other members of the Cornell team: Roslyn D. Noar, Michael S. Packer, Maria J. Harrison, Chris L. Henley, Itai Cohen, and Sharon J. Gerbode.]

Wettest Parts of Earth Getting Wetter, Driest Parts Drier

2012-04-27T16:00:00.000-04:00

Climate-driven changes in ocean salinity over last 50 years could bring floods and droughts.

Lined with bottles triggered at different levels of the ocean, this conductivity, temperature and depth profiler bearing a suite of sampling bottles is a mainstay of oceanography. Credit: (CSIRO)

The warming climate is altering the saltiness of the world's oceans, and the computer models scientists have been using to measure the effects are underestimating changes to the global water cycle, a group of Australian scientists have found.

The water cycle is the worldwide phenomenon of rainwater falling to the surface, evaporating back into the air and falling again as rain.

The wetter parts of the world are getting wetter and the drier parts drier. The researchers know this because the saltier parts of the ocean are getting saltier and the fresher parts, fresher.
Records showed that the saltier parts of the ocean increased salinity -- or their salt content -- by 4 percent in the 50 years between 1950 and 2000. If the climate warms by an additional 2 or 3 degrees, the researchers project that the water cycle will turn over more quickly, intensifying by almost 25 percent.

Reporting in Science magazine, the researchers said the results of the change in climate would affect agriculture and the ability of drier areas to capture and use fresh water from rain, creating serious problems, including droughts and floods. But they had to look offshore to find their data.

"The oceans are really where the action is happening," said Paul Durack, the lead author.
The study uses 50 years of data -- from 1950-2000 -- gathered by instruments, some adrift on the ocean currents, some tethered in place. Some of the instruments are tiers of bottles that open at various depths as they are lowered into the sea, and they take measurements as far down as 9,000 feet.

Durack, who received his Ph.D. from the University of Tasmania, and is now in a post-doctoral fellowship at Lawrence Livermore Laboratory in California, said that "salinity shifts in the ocean confirm climate and the global water cycle have changed."

The oceans cover 71 percent of the Earth's surface. They contain 97 percent of the world's water; receive 80 percent of the rainfall, and have absorbed 90 percent of the energy produced by global warming.

The relationship between salinity in the sea and the water cycle is well documented, the scientists wrote. Changes in salinity could also affect water currents because saltwater is denser than fresh water and sinks.

Warmer air can absorb more water than cooler air, so as the climate warms, more water can evaporate into the air. The amount evaporated increases 7 percent for every degree Celsius the temperature increases, the scientists reported.

That intensifies the water cycle on both ends of the spectrum. In places where rainfall exceeds evaporation, the rain is increasing; in the places where evaporation rates are higher than rainfall, it gets drier.

Some of the change is directly caused by warmer temperatures. For instance, the ocean waters around Antarctica are getting less salty because the waters are being refreshed by the melting ice cap.

Arid areas that require rainfall to provide water for irrigation, for drinking and industry, will see less rainfall, he said. That is a more significant threat than just an increase in temperature.

"Changes in the global water cycle and the corresponding redistribution of rainfall will affect food availability, stability, access, and utilization," Durack said. "I come from Perth, in dry western Australia, and you can see the change."

Most computer models depend on land-based observation, which accounts for the difference, but Durack and his collaborators, Susan E. Wijffels and Richard J. Matea, think measuring the oceans gives a more accurate picture, what they called an "identifiable fingerprint." Their work covers 71 percent of the world's water cycle.

"The most important part of the research is the basic observation that the 50-year trend in salinization is indeed that the fresh water is getting fresher and the saltwater saltier," said Dean Roemmich, a professor of oceanography at the Scripps Institution of Oceanography. "It is a fundamental change."

Joel Shurkin, Inside Science News Service

Joel Shurkin is a freelance writer based in Baltimore. He is the author of nine books on science and the history of science, and has taught science journalism at Stanford University, UC Santa Cruz and the University of Alaska Fairbanks

Six Flags Physics

2012-04-26T16:30:00.000-04:00

Ever year, members of the Physics Central team descend on Six Flags America theme park to test the laws of physics and strength of our stomachs (some fared better than others). Meanwhile, thousands of physics students enjoyed roller coaster thrills while learning some physics at our stations around the park.

This year, we came armed with accelerometers, an egg drop demo, and several other physics goodies. So strap in, and enjoy the ride.

The Batwing roller coaster at Six Flags America. Students on the ride wore special vests to measure their accleration on this and other rides. Image courtesy SPS.

At most of the major rides at the park, we had accelerometer booths set up, allowing students to see their accelerations throughout the ride. The devices measured accelerations in all directions in addition to altitude, allowing us to match each coaster's major drops with the resulting accelerations.

Acceleration data from 2011 for the Superman roller coaster courtesy Buzz contributor Echo Romeo. Click on the image for a better view. The top graph tracks the y-axis acceleration over time, and the bottom graph displays altitude over time.

Students who chose to ride with the acceleromters got to wear some stylish blue vests. And if that wasn't enough to convince them to explore the physics of the rides, they got to jump to the front of the line as well.

Yours truly handing out those stylish vests. Image Credit: Mike Lucibella.

In addition to the accelerometers, we also had several demos set up throughout the park. Perhaps the most popular demo was the egg drop from atop a crane. Students were allowed to spend up to $15 on supplies to build an egg holder that would save the egg from concrete catastrophe. Prizes were awarded for teams with surviving eggs and the most innovative designs.

The egg drop contest pits student-designed egg containers against a long fall from atop a crane. Image Credit: Mike Lucibella.

The American Physical Society, the Society of Physics Students, and the American Association of Physics Teachers have been hosting this event for years, and we'll be holding another one next spring. So if you'll be in the Washington, DC area next spring, keep your eyes peeled for Six Flags Physics Day 2013.

It's National Physics Day!

2012-04-24T16:30:00.000-04:00

Physics fans, rejoice! April 24th is National Physics Day, and physics enthusiasts across the country are celebrating with fun physics demonstrations, public lectures, and other science events.

But National Physics Day isn't new; revelers have celebrated physics on or around April 24th for the past 18 years, starting in 1995 at the University of Virginia. One year later, the National Science Foundation incorporated National Physics Day into their now defunct Science and Technology Week. Despite that program's end, National Physics Day has endured.

"It's always been focused on getting young children interested, and they're a fantastic audience," said Craig Dukes, a University of Virginia physicist who helped organize some of the first National Physics Days.

And how do you get the kids excited?

"The kids always like something that goes boom," said Dukes.

So in honor of National Physics Day, here's some awesome physics demonstrations to help you celebrate (including a couple that go boom!):

Imploding Train Car

This is a super-sized version of the imploding barrel demonstration you may see in a freshman physics class. The demonstrators boiled water in the tanker and then sealed off the tanker so that no gas could escape.

Before the tanker was sealed, the water vapor pushed all of the air out. Consequently, when the tanker was capped, the water vapor cooled back into a liquid and the pressure in the tanker plummeted. The difference between the low pressure in the tanker and the relatively high atmospheric pressure outside caused the tanker to implode with a bang.

Liquid Nitrogen Cannon

As liquid nitrogen expands into a gas, you can use it to propel projectiles.

Bubbles in Space

And here's one demo that's out of this world, literally!

Imploding drums, demos on beds of nails, and exploding balloons have been a hit at the University of Virginia's celebrations in past years, said Steve Thornton, a University of Virginia physicist who organized the first National Physics Day. Thornton has worked on National Physics Day since the beginning, and he has just started to hand the reins over to his colleagues.

So have some fun with physics this year, but remember to stay safe. Many physics demos, including the ones above, involve some risk, and kids should always be supervised by an adult.

The Solar System in the Palm of Your Hand

2012-04-23T16:30:00.000-04:00

Video games have often been targeted by critics as time wasters that distract students from their education. Although video games don't always pair well with educational material, sometimes this pairing can be fantastic.

One such example is The Solar System: Explore Your Backyard -- a forthcoming PC/iPad/iphone application that gives you the freedom to explore our solar system in all of its glory. You can travel from planet to planet, get detailed information about planets' moons and orbit, and even visualize many of the sky's constellations.

A virtual tour of the solar system application courtesy of Christopher Albeluhn.

Christopher Albeluhn, the creator of the forthcoming app, started the project as a way to update his portfolio after losing his job in video game development, according to his site. After his friend posted a video of his work, he gained a huge following and placed his project on indiegogo.com, a website dedicated to crowd-funded ideas.

Albeluhn built the app on the Unreal Engine from Epic Games, a video game studio best known for the Gears of War franchise. Instead of fending off alien hordes, the user of this app can jump from one alien world to another and learn something along the way.

Albeluhn assures his readers that all of the orbital data has been verified multiple times to ensure accuracy, and everything should be to scale. In the video above, it might look like Jupiter is larger than the sun, but that's simply because Albeluhn changed the relative scaling for a better view of the gas giant.

Here's some of the cooler features that appear in the trailer above:

Detailed orbits for all of the planets and their moons with the ability to watch them move at different speeds.
A graph of the gravitational pull for every celestial body. The graph attempts to visualize the bending of spacetime due to gravity.
Internal views of every planet with the most detailed view reserved for our Earth.
Constellations overlaid with artistic impressions (e.g. A lion will appear for the constellation Leo.

Now that Albluhn has achieved his funding goal of $8,000, he plans to move forward with publishing the application for PCs, ipads, and iphones in the coming months. With more funding, he hopes to donate his app to a local science center.

The app looks great, and it appears to give the user more freedom than many other applications on the market. To see for yourself, here's a brief list of some of the alternatives available today:

Eyes on the Universe - A free online app from NASA's Jet Propulstion Laboratory.
Brian Cox's Wonders of the Universe - A paid app for the ipad/iphone.
Worldwide Telescope - A free web app from Microsoft.

Based on the video that Albluhn has released, however, his app looks more refined and engaging. We'll see if this app lives up to the hype once it's released in the coming months.

Scientists Link Gap in Rock Record to Explosion of Life

2012-04-20T16:30:00.000-04:00

More than 500 million years ago, during a time known as the Cambrian explosion, novel categories of multicellular life forms appeared in a carnival of biological innovation unmatched in our planet's history. New research ties together this burst with an ancient mystery called the Great Unconformity.

In the Grand Canyon, sandstone lies on top of igneous and metamorphic rock, leaving as much

as a one billion year gap in the record of the Earth's history. Credit: brewbooks via flickr

The Great Unconformity refers to the huge gaps left in the planet's rock record where relatively young sedimentary rocks -- still a few hundred million years old -- sit atop much older igneous and metamorphic rocks. For example, in the Grand Canyon, 1.7-billion-year-old metamorphic rock is topped by a layer of sandstone that's about 500 million years old. Similar unconformities exist throughout much of the world, leaving a limited record precisely when life was advancing so quickly.

Many scientists, including Charles Darwin, considered gaps left in the geologic record a significant obstacle to understanding the Earth's history. But researchers now say that the process that formed this break is crucial to understanding what happened during the explosion of life.

An article in the April 19 issue of the journal Nature links changes in ancient ocean chemistry to the transformation of life. One significant change was the advent of biomineralization, when organisms first began using minerals such as calcium carbonate to build structures, including shells and skeletons.

"This is a unifying hypothesis that ties everything together into a single mechanism," said Shanan Peters, a geologist at the University of Wisconsin-Madison. "I think a lot of geologists are going to slap their heads and say, 'Of course!'"

The research links the appearance of biomineralization to the Great Unconformity. Peters and his colleague, Robert Gaines from Pomona College in Claremont, Calif., used a massive database of over 20,000 rock samples collected from across North America, to bring together many clues in what Peters called a "detective story."

The researchers hypothesize that when erosion exposed and wore down the ancient rocks that now lay below the Great Unconformity, the rocks reacted with air and water to change seawater chemistry, making key ingredients for the formation of biominerals more available.

The formation of the Great Unconformity "may have been an environmental trigger for the evolution of biomineralization and the 'Cambrian Explosion,'" the researchers wrote.

High concentrations of calcium and other elements might have made it less costly to animals to make the effort to begin incorporating minerals, said Peters.

It's not that animals noticed the availability of calcium and decided to make shells and skeletons out of the mineral, but once they began taking in and transforming minerals, natural selection may have led to the spread of the most useful structures.

"[The Cambrian explosion] was so major that it used to be thought of as the origin of life itself," said Matthew Powell, a paleontologist at Juniata College in Huntingdon, Penn., who did not work on the study. "It looked like the origin of life because that's when things acquired skeletons and could be found as fossils."

Other research has linked the Cambrian explosion to the evolution of certain genes or changes in oxygen concentration. Peters admitted that more than one factor may have enabled the event. He said that before this research, no one had linked together so many pieces in a quantifiable, cohesive fashion, nor suggested that chemistry was such a key issue.

"This is really synthesizing a lot of different ideas into a new hypothesis," said Powell. "I wouldn't characterize this as closing the debate, but it opened it very strongly."

Chris Gorski is a writer and editor for Inside Science News Service.

Visualizing Word Usage (in Science!)

2012-04-19T16:30:00.000-04:00

Uncovering historical trends can be a bit of a dark art. But in recent years, engineers and researchers have made it easy for the general public to quickly search through enormous sets of data. Google's Ngram viewer, for instance, allows users to compare word usage since 1800 in its massive digital library of books.

Ngram is pretty simple: input some words or phrases that you want to compare (e.g. "the Beatles," "Albert Einstein," and "Elvis Presley,"), pick a time range and press enter. Google then outputs a nice looking graph of the relative popularity of these terms in books throughout a given time period. If you haven't already, give it a try!

While the Ngram Viewer has been around for over a year, a similar project that tracks trends in scientific papers was recently unveiled. Called bookworm arXiv, this new tool works just like Ngram, but it searches through preprints of academic papers that scientists have posted on arXiv.org. Now it's much easier for anyone to search for the hottest research trends with a few keystrokes and mouse clicks.

Researchers at Harvard's Cultural Observatory developed the bookworm application, and they've added a few more features than Google's Ngram Viewer:

You can graph terms within physics subfields such as astrophysics or particle physics. For instance, you can graph how frequently "supernova" appears within the field of astronomy and compare this to the frequency of "graphene" in condensed matter physics.
You can compare how frequently certain universities or institutions publish to the arXiv. Now different universities can fight for the bragging rights of having the most influential arXiv authors.
You can graph papers by email domain, allowing you to focus your results to a certain country or language.

Not only can you use all of these features individually, but you can also mix and match as much as you please, leading to a highly targeted search for science trends. Below are a few examples of what you can do.

The LHC vs. Fermilab's Tevatron

The percentage of high energy physics papers that mention the Large Hadron Collider (blue) and Fermilab's Tevatron accelerator (red). More than half of these papers mentioned the LHC by 2011.

Graphene, Supernovae and Neutrinos

The appearance of graphene (blue), supernova (red), and neutrino (green) in all articles on the arXiv.

Ice Cream Battle: Chocolate vs. Vanilla

Physicists clearly prefer vanilla. Case closed.

Although arXiv papers, such as the traffic ticket paper we covered last week, aren't peer reviewed, this tool can still give you a fascinating glimpse into physics research. Submitted papers must come from a respected university or institution, so most of the articles detail legitimate research. Now go out and uncover the next trend in physics research!

Links:

Google's NGram Viewer

Bookworm arXiv

Update: Updated the top image with capitalized names because Ngram is case-sensitive.

The Sweet Spot for Positive Splits

2012-04-18T16:32:00.000-04:00

As Olympic fever has started to build for the 2012 Summer Games in London, a physicist has analyzed a peculiar aspect of 400 meter and 800 meter track races. For the vast majority of world records in these races, the runner runs the first half of the race faster than the second -- a positive split.

These consistent positive splits don't happen for shorter races (the runners tend to run faster during the second half) or for longer races (world records don't seem to favor either positive or negative splits). So Jim Reardon, a physicist at the University of Wisconsin Madison and a track coach, decided to uncover the reason using physics.

The end of a women's 100m race. Image Courtesy Beat via Wikimedia Commons.

If you take a look at the table of track world records below, there's an interesting pattern. The sample of world records in the shorter events, namely the 100 m and 200 m, have been set exclusively with negative splits, meaning that the runners end the race faster than they start.

On the other hand, the middle distances -- the 400 m (one lap) and 800 m (two lap) races -- have world records set almost exclusively with positive splits. For the longer races, it's a wash.

"There was a puzzle in the data," said Reardon. "All the good runners go out faster than they can sustain," for the 400 m and 800 m races.

To uncover the reason behind this phenomenon, Reardon developed a computer model and used differential equations to describe its behavior. In fact, the model may look familiar to students who have taken a differential equations class: Reardon modeled a runner's leg as if it were a tank that is simultaneously being filled with a fluid and drained of that fluid.

After creating the model, Reardon crafted his differential equations so that they would accurately predict the optimal pacing observed in the world record data above. With optimized equations, Reardon could look back at the model to see how it matched up with the actual biology of a runner's leg.

The X Factor

With this simple model predicting the world records seen in these medium distance races, a few questions naturally arose: what could the fluid in the leg "container" represent, and how does it affect racing performance?

To answer that question, Reardon looked through some of the physiological literature to see what the fluid in his model -- which he coined as the "X-factor" -- might be. Some physiologists think that when positive hydrogen ions build up inside of our legs, they cease to function and "burn out." Others disagree, arguing that the buildup of certain chemicals may lead to the legs ceasing to function during the races.

Regardless, something builds up in the runner's legs after extreme exertion, causing the legs to stop working effectively. Regardless of what this x-factor may be, the legs need to properly diffuse the x-factor to continue working, according to Reardon.

Just like a drop of food coloring diffuses throughout a glass of clear water, muscles in the leg rid themselves of this x-factor diffusively, said Reardon. Here, Reardon's modeling of the leg as a container becomes more clear. More and more x-factor "fluid" builds up during the course of the race, and the leg has to efficiently drain it to maintain performance.

According to Reardon's research, this process plays an important role in the medium races but not the other races. First, the short races don't last long enough for the leg muscles to wear out, so the x-factor doesn't become an issue. For the longer races, the body equilibrates over a long enough period of time, and other variables, such as VO2 max, become more important for determining pacing.

"In the middle, there's this range where it matters," said Reardon.

There are certain strength training exercises that will likely make the legs more efficient at diffusing the X-factor, according to Reardon. He doesn't anticipate big changes in his training regimen in light of this research, however.

Instead, Reardon hopes that this research may inspire educators to include coursework problems that touch on this model. Differential equations students cover the same mixing problems over and over, and Reardon hopes to break the monotony.

"There's a new problem and the math isn't at a higher level," said Reardon. "And it leads to some results that may be relevant in the real world."

Reardon's research paper has been submitted to the American Journal of Physics and is currently being reviewed. You can see his paper currently on the arXiv.

Discovery's Last Flight

2012-04-18T09:13:00.002-04:00

Space shuttle Discovery, mounted atop a NASA 747 Shuttle Carrier Aircraft (SCA), makes its way past Ronald Reagan Washington National Airport on April 17 in Arlington, Va. Photo credit: NASA/Bill Ingalls.

Yesterday the shuttle 'Discovery' flew from Florida to DC where it will be put on permanent display at the Air and Space Museum. No, you will not be able to crawl through it and pretend you are an astronaut, but yes you will be able to see an amazing piece of US space flight history. Members of the Physics Buzz team were lucky enough to watch the flight at the NASA Goddard Space Center. Views may have been better downtown, but seeing the fly-over with a huge crowd of NASA scientists and their space-enthusiat family and friends was quite an experience. One employee's children even brought their stuffed shuttles. Here is a video of this great event.

There are many other videos from varying places around DC, but I have to say that watching it from a NASA facility was very much a highlight. Hundreds of people of all ages gathered for the show. One of the most interesting things is that as it flew over, no one seemed to know whether to cheer or mourn. It was a sea of mixed emotions. To me, space flight was defined by these shuttles. My whole life the image of the black and white, flag adorned space ships was the definition of human space exploration. I was of the group that was mourning.

Discovery over D.C.

2012-04-16T16:35:00.000-04:00

It's a bird. It's a plane. It's...Space Shuttle Discovery. Tomorrow morning (Tuesday) between 10 a.m. and 11 a.m. Eastern Time, the retired Discovery Space Shuttle will fly low over Washington, D.C. en route to Dulles International Airport in Virginia. Onlookers will be able to see the spacecraft from the ground at several D.C. landmarks.

Discovery won't make the journey from Florida to D.C. alone, however: the spacecraft will piggyback on NASA's 747 Shuttle Carrier Aircraft. Discovery's journey kicks off a week-long celebration of NASA's transfer of the spacecraft to the Smithsonian Air and Space Museum for public display.

Shuttle Endeavor on top of NASA's Shuttle Carrier Aircraft. Image Courtesy NASA.

Since the retirement of the Space Shuttle program last summer, NASA has been working with museums and science centers to relocate the shuttle orbiters for public display. Many locations competed to house the four coveted orbiters, and NASA's eventual decisions last year were met with controversy.

Nevertheless, NASA hopes to deliver all of the shuttles to their final homes by the end of the year, starting with Discovery this week. Here's a list of the other shuttles and their respective display locations:

Discovery: Smithsonian Air and Space Museum's Udvar-Hazy Center, Chantilly, Virginia
Enterprise: Intrepid Sea-Air-Space Museum, New York City, New York
Atlantis: Kennedy Space Center, Merritt Island, Florida
Endeavour: California Science Center, Los Angeles, California

For the best locations to see Discovery's flyby tomorrow, take a look at this map provided by the Smithsonian Air and Space Museum.

The best locations in and around Washington, D.C. to see the shuttle's approach to Dulles International Airport. Great views can also be seen from the Udvar-Hazy Center in Chantilly Virginia.

Discovery certainly has already made a lasting impact on the history of manned spaceflight. Since its first flight in 1984, the spacecraft has traveled almost 150 million miles, deployed 31 satellites, and docked with the International Space Station 13 times. For more facts about Discovery and its sister shuttles, take a look at this NASA webpage.

Will 3-D Printing Launch A New Industrial Revolution?

2012-04-13T16:02:00.000-04:00

Peter Schmitt, an MIT doctoral student, printed a clock in 2009. He didn't print an image of a clock on a piece of paper. He printed a three-dimensional clock -- an eight-inch diameter plastic timekeeping device with moving gears, hands and counterweights. When he put it up on a wall and pushed the counterweight, it went ticktock.

Credit: bre pettis via flickr

"It wasn't very accurate, but it was a functioning clock," Schmitt said.

MIT scientists also would like you to be able to print your own robot. Their vision: Decide what you want it to do, download the design from the Internet, use software to make whatever changes you want and hit "print."

Scientists around the world are working on a technology that could go well beyond robots and clocks and turn the world's economy upside-down. It goes by the name of 3-D printing, and some proclaim that it will trigger a new Industrial Revolution. The Atlantic Council, an industry consulting firm based in Washington, D.C., says the technology is "transformational."

Those working in the field call it "additive manufacturing."

Much of modern manufacturing is by reduction. Manufacturers take blocks of plastic, wood, or metal, and grind and machine away until they get the item they want. All the plastic, wood, or metal that doesn't make it into the item is thrown away, maybe as much as 90 percent wasted.
3-D printing puts down layers of metal powders or plastics as directed by software, just as ink is laid down on paper directed by printer drivers. After each layer is completed, the tray holding the item is lowered a fraction of a millimeter and the next layer is added. Printing continues until the piece is complete.

Molten metal is allowed to cool and harden; plastics or metal powders are hardened by heat or ultraviolet light. The ingredients aren't limited to those substances; almost anything that flows can be accommodated, even chocolate.

There is little waste, and it is possible to change the object by simply working with the software that drives the printer the way text is changed in a word processor.

The end products may be better or possibly more beautiful than current products, the council wrote in a research report. 3-D printing allows designs impossible to make with conventional manufacturing techniques.

The first 3-D printer was invented by the American Charles Hull in 1984. The first machines were huge, slow, very expensive, and had limited use.

In 2004, Adrian Bowyer, a lecturer at Bath University in England, invented a machine that manufactured 50 percent of its own parts and in 2008, the machine printed itself. There was no real profit to be made in a self-replicating machine so Bowyer put the RepRap in the public domain, "open source" in the lexicon. Anyone could buy this desktop printer for under $400 and adapt it at will to print more copies of itself, or other items.

The design keeps improving as people think of better ways to do things, a form of crowd-sourcing, and users share designs online, often for free.

Additive manufacturing, meanwhile, became a huge and growing industry. According to Wohler Associates, a Colorado consulting firm, the industry has sustained an annual growth rate of 26.2 percent for more than 20 years and revenues will reach $3 billion by 2016.

Every year the technique turns out more complex artifacts, faster and cheaper. The technology is now used to print aircraft landing gears, dresses, car parts, individualized tooth crowns, artificial hips and knees, and more.

Scientists are experimenting with human cells to print organs. An Airbus contractor is working on printing an entire aircraft wing using titanium powder. Parts of the fuselage of Boeing's 787 Dreamliner were printed.

Printing a robot is far more complicated than building a clock, but researchers at MIT, the University of Pennsylvania and Harvard think the result will "transform manufacturing and … democratize access to robots," according to MIT's Daniela Rus, leader of the project.

You could identify a need -- say cleaning up the kitchen floor after a kid spilled lunch -- and design a robot specifically for tasks like that. You would download a design from the Internet, adjust to customize it for your kitchen, and print out exactly the robot you designed, moving parts and all.

The researchers already have printed two robots, including one designed to go into contaminated areas and one with a gripper that would help people with disabilities.

The technology introduces serious issues for the world economy.

Most finished products now are the result of many parts manufactured in various places around the world, coming together for assembling into one product. They are then shipped to customers around the world. With 3-D printing, in theory, the entire product would be made at one site, at one time, in one machine, anywhere. Economies of scale would be irrelevant.

"Printing a few thousand iPhones on demand (and with instant updates or different versions for each phone) at a local facility that can manufacture many other products may be far more cost-effective than manufacturing ten million identical iPhones in China and shipping them to 180 countries around the world," the Atlantic Council wrote in a report.

Clearly, not everyone would share the advantages. Manufacturing centers like China could lose millions of jobs in that sector, and their economies could be destabilized. The industries that transport the supply line and distribute the finished product would also be hit, the council wrote. Warehouses full of parts and products could be replaced by machines that print on demand.

The council predicts a renaissance in American manufacturing. But that concept has issues too: most of the machines require no human assistance once the printing starts. You turn it on before you leave the factory and when you come back in the morning, your widget is there.

Joel Shurkin, Inside Science News Service