While most of the campus community was on vacation for the winter term, plenty of researchers at this university were busy publishing the results of their scientific studies. These are the ones you should know about:

MTV shows such as Teen Mom help decrease rate of teenage birth rates

In a study that examined the social effects of shows such as 16 and Pregnant and Teen Mom on U.S. teen birth rates, a university economist found that the MTV shows led to a 5.7 percent drop in teen births in the year and a half after they premiered in 2009.

University economist Melissa Kearney, along with Wellesley College co-author and economics professor Phillip Levine, found that, beginning in 2009, the rate at which teenage births were dropping made a significant jump.

“Teen births had been falling steadily — about 2.5 percent per year,” Kearney said. “But we noticed a 7.5 percent drop starting in 2009.”

The study was not the first to examine the effect of such media on society, but it was one of the first to separate causation from correlation, Kearney said. The research showed that locations with higher viewership of the two shows experienced a more drastic drop in teenage child-bearing, Kearney said, while areas with lower viewership experienced little change outside the norm.

“Studies have shown that teens who view programs with sexual content are more likely to be sexually active,” she said. “But that doesn’t rule out the possibility that teens who are more interested in sex just watch programs with sex because they’re interested. This is the first study that we know about that can demonstrate a causal relationship.”

The researchers looked at Twitter data and Google search data as well and found that searches such as “how to get birth control” and “how to get an abortion” increased in numbers in the 24 hours after the show aired.

While there are no plans for continued research, Kearney said she is interested in whether there are similar effects on European teens.

Forty percent of U.S. males arrested by age 23

Criminology professor Ray Paternoster and other researchers discovered a trend after combing through survey data from 1997 to 2008: Forty-nine percent of black males, 44 percent of Hispanic males and 38 percent of white males in this country had been arrested by the time they turned 23.

Published in the academic journal Crime & Delinquency, the study examined self-reported arrest histories from the National Longitudinal Survey of Youth 1997. Paternoster and his colleagues then categorized the statistics by race and sex.

The researchers analyzed the same data for females and found less variance, with 20 percent of white females, 18 percent of Hispanic females and 16 percent of black females arrested by age 23.

Paternoster said the results were almost on par with the researchers’ expectations.

“I knew the arrest rates for males would be pretty high,” he said. “The results are probably a little higher, but no, I’m not surprised.”

The last time a similar study was conducted was in 1967, when 34 percent of all American men had been arrested by 23, Paternoster said. This study found the number had increased to 40 percent — a fairly small increase, given the jump in arrests made for crimes such as marijuana possession, he said.

But considering that arrest records are so accessible by way of the Internet, these arrest statistics could pose a problem in job searches for new adults with criminal histories, Paternoster said.

“Arrests are fairly common, and yet they’re still an obstacle to overcome,” he said. “Employers have such easy access to arrest records.”

Racism matures black men at an accelerated rate

A research study led by a scientist at this university found that effects of racism include a more rapid aging process at the cellular level.

The study, led by epidemiology professor David Chae, discovered a pattern of shortened telomeres — the protective end-caps on chromosomes that keep genetic information intact — in individuals who perceived a more negative impact from racism.

Because telomeres gradually wear away over time, they have been linked to age determination in humans.

“This is the first study to explicitly look at racism and how it affects [us] at the cellular level,” Chae said.

The research included a sample size of 92 black men aged 30 to 50 in the San Francisco Bay Area. The subjects were asked to answer questions about their experiences with racism and how they viewed their race.

Those who reported more negative experiences or demonstrated damaged self-concept were found to have shorter telomeres. From a biological standpoint, they were found to be older than their less-affected counterparts, Chae said.

“When we feel people are treating us poorly, we feel a physiological change,” he said. “Our blood pressure goes up; our faces get flushed. Racial discrimination is qualitatively different because it attacks our identity. Imagine that happening on a day-to-day basis.”

While the findings in the study were conclusive of the trend, Chae said there is room for improvement.

In future research, he said he plans to increase the sample size, take subjects from a larger geographic area and follow them for a longer period.