Signals for Lorentz Violation in Electrodynamics

An investigation is performed of the Lorentz-violating electrodynamics extracted from the renormalizable sector of the general Lorentz- and CPT-violating standard-model extension. Among the unconventional properties of radiation arising from Lorentz violation is birefringence of the vacuum. Limits on the dispersion of light produced by galactic and extragalactic objects provide bounds of 3 x 10^{-16} on certain coefficients for Lorentz violation in the photon sector. The comparative spectral polarimetry of light from cosmologically distant sources yields stringent constraints of 2 x 10^{-32}. All remaining coefficients in the photon sector are measurable in high-sensitivity tests involving cavity-stabilized oscillators. Experimental configurations in Earth- and space-based laboratories are considered that involve optical or microwave cavities and that could be implemented using existing technology.Comment: 23 pages REVTe

Linking domain and situated motivation for writing with writing performance and experiences

Writing motivation, in terms of students' attitudes, values, beliefs, and goals, has a significant influence on writing achievement. However, much remains to be discovered about how this relationship unfolds over time, is affected by writing experiences, and is differentiated by general and context specific motivation measures. This presentation will report findings from a study conducted with nearly 750 students in grades 4 through 12 in two states that was designed to examine the connections between general and contextualised writing motivation, frequency and types of writing experiences, and writing performance reported by teachers and measured independently through trait scoring