News, Science & Research

Science and Research Roundup, Sept. 17

By and
Science and Research Editor and University News Editor
Tuesday, September 17, 2019

Sharks shrug shoulders to swallow, study shows

Without tongues to move food through their mouths, some sharks use their shoulders instead to pull food down their digestive tracts.

A University study published in Proceedings of the Royal Society B used new X-ray technology developed at Brown to capture video footage of bamboo sharks’ muscle and bone movements while they ate. The X-ray videos allowed researchers to see how the sharks quickly swing their shoulder bones to create suction, which moves food back through their mouths.

The study only examined bamboo sharks, but Ariel Camp — the paper’s lead author and a postdoctoral researcher at the University — believes other shark species likely also use their shoulders to help ingest food. This newly documented shoulder function may help researchers understand why some fish evolved shoulders to begin with, Camp said in a University press release.

University study finds more engaging teachers increase student attendance

As middle and high school students begin making their own decisions about whether to attend class, their teachers have a major impact on their attendance rates, according to a recent study from the Annenberg Institute for School Reform. Specifically, some teachers were more effective than others at promoting attendance, suggesting that more engaging teachers can reduce unexcused absences.

The study — conducted by Annenberg Institute Director Susanna Loeb and Jing Liu, a postdoctoral research assistant — attempts to create a new measure for evaluating teachers beyond their impact on test scores. “There are multiple dimensions of good teacher quality,” Loeb said in an interview with Chalkbeat.

Teachers’ effects on students continue beyond attendance. In the study, the same teachers who boosted attendance also increased both students’ likelihood of taking Advanced Placement courses and their likelihood of graduating from high school.

University study dives into volcanic magma chamber’s ideal depth

New research explains why volcanic chambers that store magma lie within a specific range below the surface of the Earth. The underground caverns that hold magma reside at a “sweet spot” that is roughly six to 10 kilometers below the surface. Using computer models, researchers from the Department of Earth, Environmental and Planetary Sciences found that this is the depth at which volcanic pressures are ideal.

The study found that the location of magma storage is defined by the pressure at which magma can be stably maintained and renewed. The pressure present at this depth is usually between 1.5 and 2.5 kilobars. Pressures outside this range can lead to violent eruptions, according to the news release.

“Between 1.5 and 2.5, the systems are happy,” said Christian Huber, the study’s lead author and a professor of earth, environmental and planetary sciences, in the news release. “They can erupt, recharge and keep going.”

This research also helps scientists understand the ratio of magma that is stored under the Earth compared to how much erupts onto the surface. More broadly, understanding this process helps researchers make sense of volcanic activity in general, which has implications for climate science. “Magma supplies (carbon dioxide) and other gases to the atmosphere, which influences the climate. So having a guide to understand what comes out and what stays in is important,” Huber said in the news release.