No abstract

Elementary, middle-level, and high school science teachers commonly find their students have misconceptions about heat and temperature. Unfortunately, student misconceptions are difficult to modify or change and can prevent students from learning the accurate scientific explanation. In order to improve our students' understanding of heat and temperature, we created a three-part instructional activity designed to engage them in the development of kinetic particle models. First, the students use household materials-food coloring and water-to investigate and create particle models depicting motion at the molecular level. Second, the students complete a similar activity designed to help them visualize the connections between heat and particle motion. Third, the students build a thermometer, observe it in action, and create particle models explaining how the thermometer works. By the end of the series of activities, the students are able develop their own definitions for heat and temperature. Through this hands-on and minds-on series of activities, students learn to define and differentiate the concepts of heat and temperature.

The biological concept of bilateral symmetry as a marker of developmental stability and good health is well established. Although most individuals deviate slightly from perfect symmetry, humans are essentially considered bilaterally symmetrical. Consequently, increased fluctuating asymmetry of paired structures could be an indicator of disease. There are several published studies linking bilateral breast size asymmetry with increased breast cancer risk. These studies were based on radiologists' manual measurements of breast size from mammographic images. We aim to develop a computerized technique to assess fluctuating breast volume asymmetry in screening mammograms and investigate whether it correlates with the presence of breast cancer. Using a large database of screening mammograms with known ground truth we applied automated breast region segmentation and automated breast size measurements in CC and MLO views using three well established methods. All three methods confirmed that indeed patients with breast cancer have statistically significantly higher fluctuating asymmetry of their breast volumes. However, statistically significant difference between patients with cancer and benign lesions was observed only for the MLO views. The study suggests that automated assessment of global bilateral asymmetry could serve as a breast cancer risk biomarker for women undergoing mammographic screening. Such biomarker could be used to alert radiologists or computer-assisted detection (CAD) systems to exercise increased vigilance if higher than normal cancer risk is suspected.