Coherent electronic energy transfer and nonlinear polariton effects in anthracene-doped naphthalene crystals

The nature of electronic energy transfer in strain-free mounted anthracene-doped naphthalene single crystals at frequencies near that of the (0.0) a-exciton in naphthalene was probed using sensitized resonant two-photon fluorescence excitation (TPE) and second harmonic generation (SHG) spectroscopies. The naphthalene-to-anthracene TPE intensity ratios were found to be 1.2 and 1.6, for excitation of the zero-phonon transition at 1.6 K and 20 K, respectively. This result is consistent with coherent exciton-polariton electronic energy transfer at liquid helium temperatures, and incoherent transfer at high temperatures. Energy transfer for the pure and the anthracene-doped naphthalene systems under investigation was determined to be in the capture limited regime, that is, the trapping event occurs on a timescale which is long compared to the migration of the excitation to the trap. The polariton trapping event is discussed in terms of scattering off a trap with subsequent trapping (i.e., capture) and scattering off a trap without subsequent trapping (i.e., trap scattering). The branching ratio for the trap scattering frequency to the capture frequency, (gamma)(,sc)/(gamma)(,tr), was derived and was calculated to be 5 to 1 for the doped system. The branching ratio was used to determine the individual scattering frequencies: (gamma)(,sc) = 2.5 x 10(\u2710) sec(\u27-1) and (gamma)(,tr) = 5 x 10(\u279) sec(\u27-1). A lower bound for the coherent trapping or trap scattering radius was determined to be 100 (ANGSTROM);Thermal broadening and temperature dependences of the TPE and SHG signal intensities for both naphthalene and anthracene are presented and are discussed in terms of the polariton fusion model. The experimental data do not agree with the theoretical predictions; this discrepancy is discussed in terms of the anomalous crystal habit (diamond plates) observed in the present investigation;The first report of a longitudinal exciton in a doped organic molecular system also is reported; *USDOE Report IS-T-1259. This work was performed under contract No. W-7405-Eng-82 with the U.S. Department of Energy

Tales from the Abyss: Unlearning Not to Speak Embodied Expressions of Pain

Produced by The Center on Disability Studies, University of Hawaii at Manoa Honolulu, Hawaii and The School of Social Sciences, The University of Texas at Dallas Richardson, Texas for The Society for Disability Studies

Implementing a Least-Restrictive Environment in a Movement-Education Camp for Children and Youth with Autism/PDD

Produced by The Center on Disability Studies, University of Hawai'i at Manoa, Honolulu, Hawai'i and The School of Social Sciences, The University of Texas at Dallas, Richardson, Texas for The Society for Disability Studies

Cyberbullying: Taking Control through Research-Based Letter Writingdents

According to a 2009 AP-MTV survey of 1,247 people ages 14–24, 50% of those surveyed have experienced cyberbullying (Gatti 1). Victims were twice as likely to need help from a mental health professional and were three times more likely to drop out of school than those surveyed who did not report being cyberbullied (5).Given this alarming social context and in light of the new Common Core State Standards (CCSS) for ELA/Literacy, we—Maureen (a high school English teacher) and Vicky (a teacher educa-tor)—decided to collaborate on a standards-based writing assignment that gives adolescent students strategies to use when they experience bullying in cyberspace and that helps prepare content-area teachers to address this issue. All teachers can use writing to help students examine their role in preventing bullying. This article describes our cyber-bullying lesson, which is discussed in more detail in our book, Getting to the Core of English Language Arts, Grades 6–12: How to Meet the Common Core State Standards with Lessons from the Classroom

Utilizing the Writing Process to Develop Meaningful Arguments

With the advent of the Common Core State Standards (CCSS) (2010), argument writing has assumed a dominant role in writing instruction. Even though most students learn to argue from a young age, as they advance in the middle school grades, they must acquire more structured and sophisticated writing skills that support logical, evidence-based arguments. Many teachers feel overwhelmed with the demands of CCSS implementation and may feel concern regarding how to teach argument writing to make it accessible to students with varying academic abilities and learning styles. Based on our experiences teaching writing instruction on the secondary and college levels and providing staff development to teachers for more than thirty five years combined, we argue that though the task of teaching argument writing is challenging, with varied approaches, teachers and students can succeed. In this article, we provide teachers with instructional strategies for argument writing that align with the model of process writing