Impact of automated response systems on in-class cell phone use.

Cell phones have long been known as a potential distraction from attention intensive activities such as studying and driving. Many, however, are developing the cell phone as a powerful tool to augment some of these same activities. Audience response systems (ARSs) are a type of teaching tool that allows educators to poll audience members in real time. Increasingly, cell phones are being integrated into ARSs to make them more versatile and affordable. As cell phones and other personal electronic devices (tablets, laptops) are becoming more common classroom learning tools, we sought to explore how student cell phone use is impacted by this change. Additionally, we studied how a student's seat location and how the time during a term impacts students' cell phone use. To measure student cell phone use in lecture, we observed introductory biology classes at the University of Washington and recorded when students' cell phones were visible. We found that students sitting in the back of the room showed an increased likelihood of having a cell phone out. However contrary to our expectations, students using personal device (cell phone) based polling technology were no more likely to be using cell phones during lecture than their peers using traditional ARSs. Our results suggest that the downsides to using cell phones as teaching tools may be limited. © 2019 The International Union of Biochemistry and Molecular Biology, 47(5):538-546, 2019.

Dental root size in bats with diets of different hardness.

The relationship between tooth roots and diet is relatively unexplored, although a logical relationship between harder diets and increased root surface area (RSA) is suggested. This study addresses the interaction between tooth morphology, diet, and bite force in small mammals, phyllostomid bats. Using micro computed tomography (microCT), tooth root morphology of two fruit-eating species (Carollia perspicillata and Chiroderma villosum) and two insect-eating species (Mimon bennettii and Macrotus californicus) was compared. These species did not differ in skull or estimated body size. Food hardness, rather than dietary classification, proved to be the strongest grouping factor, with the two insectivores and the seed-processing frugivore (C. villosum) having significantly larger RSAs. Bite force was estimated using skull measurements; bite force significantly correlated with tooth RSA but not with body size. Although the three durophagous species did exhibit larger crowns, the area of the occlusal surface did not vary among the four species. There was a linear relationship between root size and crown size, indicating that the roots were not expanded disproportionately; instead the entire tooth was larger in the hard diet species. MicroCT allows the nondestructive quantification of previously difficult-to-access tooth morphology; this method shows the potential for tooth roots to provide valuable dietary, behavioral, and ecological information in small mammals. J. Morphol. 276:1065-1074, 2015. © 2015 Wiley Periodicals, Inc.

Structural analysis of human rib fracture and implications for forensic interpretation.

Patterns of rib fractures are of significant clinical and forensic interest. Linking patterns of rib fracture with specific physical events provides a foundation for understanding the nature of traumatic events that are associated with rib fracture in forensic contexts. In this study, isolated human ribs (n = 8) were end-loaded to failure to investigate: (i) local deformations (bone strain) prior to and during structural failure, (ii) location of ultimate failure, and (iii) fracture mode. Structural properties of ribs were used to calculate theoretical stresses to determine whether such calculations could be used to predict site of fracture. Ribs fractured on the sternal side of midshaft in all experiments, but mode of failure varied with transverse, buckle, spiral, and "butterfly" fractures observed. Comparison of calculated stress with observed strain values suggest that experimental, rather than theoretical, approaches will be most productive in furthering understanding rib fracture in forensic contexts.