The production of photons at large transverse momentum can be used as a direct probe of quark and gluon subprocesses at short distances. We calculate the cross section for high-pT photons produced in pp collisions from lowest-order quantum-chromodynamics (QCD) and higher-order constituent-interchange-model (CIM) processes. We find that CIM terms dominate both y and .n spectra until very high pT-although there are regions of s and pT where the CIM contributions dominate the y spectrum but the n spectrum already shows the scaling behavior of lowest-order QCD, and also vice versa. We emphasize that in some processes (e.g., gluon + quark-photon + quark), the photon is produced without accompanying toward-side hadrons.
We present a qualitative study designed to examine how students construct an understanding of the human eye and vision from their knowledge of light and optics. As would be expected, vast differences are shown to exist between pre-and post-instruction students in terms of not only resource use, but also willingness to transfer their existing knowledge. However, we have found that appropriate scaffolding can facilitate resource activation and guide students to construct an understanding of vision and vision defects.
A great deal of literature exists surrounding the misconceptions that students have regarding the moon, specifically how the moon phases and eclipses occur. These studies provide teachers with information regarding what misconceptions their students may come to the classroom with as well as some ideas as to how to approach and correct them. However, these methods are not always validated with classroom-based research, and much of the research that has been done is in the high school and college setting. As such, we have undertaken a study to investigate what a group of middle school students know about the moon pre-instruction, and how hands-on activities and computer simulations affect student learning and understanding of these topics. The results of this project show that neither supplementation was distinguishably more effective in improving student test scores, as measured by normalized gains; this may be an artifact of high pre-test scores, as described herein.
Resonance is typically studied in the context of either a pendulum or a mass on a spring. We have developed an apparatus that enables beginning students to investigate resonant behavior of changing magnetic fields, in addition to the properties of the magnetic field due to a wire and the superposition of magnetic fields. In this resonant system, a compass oscillates at a frequency determined by the compass's physical properties and an external magnetic field. While the analysis is mathematically similar to that of the pendulum, this apparatus has an advantage that the magnetic field is easily controlled, while it is difficult to control the strength of gravity. This apparatus has been incorporated into a teaching module on magnetic resonance imaging.
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