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March 18, 2015

In Research

A close call of 0.8 light-years

two red suns in the solar system
“Scholz’s star” is likely to have passed through the solar system’s distant cloud of comets, the Oort Cloud, according to a group of astronomers led by Eric Mamajek, associate professor of physics and astronomy. No other star is known to have ever approached as close.

A group of astronomers from the United States, Europe, Chile, and South Africa have determined that a recently discovered dim star is likely to have passed through the solar system’s distant cloud of comets, the Oort Cloud, 70,000 years ago.

In a paper published in Astrophysical Journal Letters, lead author Eric Mamajek, associate professor of physics and astronomy, and his collaborators analyzed the velocity and trajectory of the low-mass star system nicknamed “Scholz’s star.” The star’s trajectory suggests that it was astronomically close—about 0.8 light-years away. No other star is known to have ever approached as close.

Mamajek worked with former Rochester undergraduate Scott Barenfeld (now a graduate student at Caltech) to simulate 10,000 orbits for the star, taking into account the star’s position, distance, and velocity, the Milky Way galaxy’s gravitational field, and the statistical uncertainties in all of those measurements. Of the 10,000 simulations, 98 percent showed the star passing through the outer Oort cloud. Only one of the simulations brought the star within the inner Oort cloud, which could trigger so-called “comet showers.”

While the close flyby of Scholz’s star likely had little impact on the Oort Cloud, Mamajek says “other dynamically important Oort Cloud perturbers may be lurking among nearby stars.” The recently launched European Space Agency Gaia satellite is expected to map the distances and measure the velocities of a billion stars.


Word-of-mouth more important than social media for TV viewing

While social media—especially Twitter—can benefit a television show in real-time, offline word-of-mouth is more influential to get a new viewer to watch a new program, thus increasing a show’s ratings, according to research from the Simon Business School.

“Our research, which included a major data integration effort, shows that television viewing is influenced by all types of communication, whether it’s social media, offline word-of-mouth, or a text message,” says lead researcher Mitchell Lovett, associate professor of marketing at Simon.

The study examined the likelihood a viewer would tune in to a program after receiving a message about the show by word-of-mouth, promotions, social media, or SMS/text message.

Results show that for repeaters—individuals who watch the same program regularly—and infrequents—individuals who do not view the same show regularly—offline word-of-mouth is the strongest form of communication that influences their television viewing. For infrequents, social media communications are more influential than promotions for shows, whereas for repeaters the opposite is true.


Study details burden of C. diff in U.S.

purple stained bacterium
A medical illustration of Clostridium difficile.

A new study led by scientists at the Centers for Disease Control and Prevention, with support and data from researchers at the Medical Center, estimates that Clostridium difficile or C. diff caused almost half a million infections in the United States in 2011.

C. diff, a bacterial infection that can cause life-threatening diarrhea, is most often associated with hospitals. But, the latest analysis estimates that only a quarter of health care–associated cases (cases in which an individual had some interaction with a health care facility) occurred in the hospital, suggesting that the majority arose in other settings, such as nursing homes or following a doctor’s visit.

Study author Ghinwa Dumyati, director of the communicable diseases surveillance and prevention program at the Center for Community Health, says that taking antibiotics is the most important risk factor for developing C. diff. In the process of wiping out disease-causing bacteria, antibiotics also eliminate beneficial bacteria that are normally present in the gut and protect against infection. It gives organisms like C. diff an open playing field to replicate.

“If we are going to prevent this infection, we have to take a broad approach by targeting antibiotic use in the hospital, in long-term care facilities, and in doctor’s offices and other outpatient care settings,” says Dumyati, associate professor of medicine. “Though a vaccine is in development, and fecal transplants are showing some promise in treating C. diff infection, we can’t wait for these to come to fruition; we need to address the problem now, and the best way to do that is by improving the appropriate use of antibiotics.”

The study, which was published in the New England Journal of Medicine, is the largest U.S. population–based survey of C. diff infections to date. The CDC collected data from 10 geographic locations in the United States, including Rochester.

Prevention remains a national priority, and over the next five years the CDC, in collaboration with partners in health care, public health, academia, and others, will work to combat C. diff and antibiotic resistance as part of the National Strategy to Combat Antibiotic Resistant Bacteria.


Teacher candidates lack clear understanding of new performance assessment

According to a recent study by Warner School researchers, teaching candidates in Washington and New York—the first two states that have required completion of the edTPA process for teacher certification—felt unprepared during the first year of the assessment’s implementation in 2014.

The study, conducted by Kevin Meuwissen, assistant professor of teaching and curriculum, and Jeffrey Choppin, associate professor of teaching and curriculum, represents one of the first attempts to document teaching candidates’ perspectives of and experiences with edTPA. The study indicates that half of those surveyed who had completed the edTPA test had a good understanding of the assessment, its criteria, and its aims during its initial year of high-stakes use in these two states.

Developed by Stanford University and the American Association of Colleges for Teacher Education, the edTPA assessment aims to improve student outcomes by quantifying the success of teacher preparation programs. The edTPA centerpiece is a portfolio submitted by teacher candidates that addresses planning, instruction, assessment, and includes lesson plans, student work samples, videos of candidates teaching, teacher feedback, and commentaries explaining and contextualizing their submissions.

“Many of the candidates’ concerns about edTPA were not necessarily linked to components of the assessment, but rather the rapid implementation process, which created stress and confusion,” says Meuwissen. “In New York, especially, the concerns of the candidates participating in the study also reflected some of the antagonism between the state education department and their teacher education institutions. It is important that relationships are strengthened across different levels of policy and practice in order to make this beneficial for students preparing for successful teaching careers.”

The researchers also suggest that states using edTPA for certification consider a rollout model that looks more like Washington’s than New York’s in order to help strengthen these networks and foster an understanding of edTPA.


Curious monkeys share humans’ thirst for knowledge

A study by researchers at Rochester and Columbia University shows that rhesus macaques have such robust curiosity that they are willing to give up a surprisingly large portion of a potential prize in order to quickly find out if they selected the winning option at a game of chance.

Monkeys are notoriously curious, and new research has quantified just how eager they are to gain new information, even if there are not immediate benefits. The findings offer insights into how a certain part of the brain shared by monkeys and humans plays a role in decision making, and perhaps even in some disorders and addictions in humans.

The study, by researchers at Rochester and Columbia University, shows that rhesus macaques have such robust curiosity that they are willing to give up a surprisingly large portion of a potential prize in order to quickly find out if they selected the winning option at a game of chance.

“It’s like buying a lottery ticket that you can scratch off and find out if you win immediately, or you can buy one that has a drawing after the evening news,” says Benjamin Hayden, co-senior author of the study and assistant professor of brain and cognitive sciences at Rochester. “Regardless, you won’t get the money any more quickly, or in the case of the monkeys, they won’t get the squirt of water any sooner. They will just find out if they selected the winning option.”

The researchers say the study, which was published in Neuron, helps to build a broader understanding for how curiosity—information seeking—is processed and rewarded in the brain.

Like monkeys, when curious we evaluate what we’d be willing to pay—or give up—to satisfy our curiosity, Hayden says. And in the case of gambling, there is also the potential of a prize to factor in. So when we make a choice, it depends on the sum of those two things: the gamble (the money you might win), and the value of finding out. And those two things need to be combined in order to make decisions about that gamble.

“One of the reasons this research is important,” Hayden says, “is because this basic desire for information turns out to be something that’s really corrupted in people with anxiety, depression, obsessive-compulsive disorder, and addiction, for example.”

“We think that by understanding these basic circuits in monkeys we may gain insights that 10 to15 years down the road may lead to new treatments for these psychiatric diseases,” he says.


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