Matter Wave Scattering from Ultracold Atoms in an Optical Lattice

We study matter wave scattering from an ultracold, many body atomic system trapped in an optical lattice. We determine the angular cross section that a matter wave probe sees and show that it is strongly affected by the many body phase, superfluid or Mott insulator, of the target lattice. We determine these cross sections analytically in the first Born approximation, and we examine the variation at intermediate points in the phase transition by numerically diagonalizing the Bose Hubbard Hamiltonian for a small lattice. We show that matter wave scattering offers a convenient method for non-destructively probing the quantum many body phase transition of atoms in an optical lattice.Comment: 4 pages, 2 figure

The Human Frontier: Building an Inclusive Organizational Culture

Is space really the final frontier, as Star Trek asserts? It seems the final frontier we have been exploring since the dawn of time is understanding ourselves and our relationships with each other. Miller and Katz (2002) say: “The creation of cultures that are truly inclusive provide the possibility of a new vision—a new human frontier.” This article uses material from U.S. pop culture from Star Trek to Woodstock and more to explore how ordinary earthlings in the present time can define, measure and build an inclusive organizational culture

Implementing a Career Development Program for Student-Athletes

When synthesized with a fundamental academic support program, a career development program can prove to be a valuable source of information and education. Guidance about careers and academic disciplines, plus the experiential opportunities that link classroom knowledge and practical experience, have been shown to be helpful in focusing the interests and energies of young adults. This article described the Wildcat Career Development Program, which was initiated at the University of Kentucky in the fall of 1991

Wh- questions and individuals with intellectual disability

The purpose of this study was to investigate the comprehension of questions beginning with different wh- question words presented in two referential conditions to individuals with intellectual disability (ID). Thirty-nine school-age participants completed a battery of who, what, where, when, why, and how questions with and without a picture referent. Students generally answered more questions correctly in the no referent condition. Across conditions the rank ordering of correct responses for each question word was: what, who, where, how, why, when. While logistic regression analysis revealed a finding of no overall statistical significance between the probability of answering questions correctly between referential conditions, there were important qualitative differences in the way students answered certain wh- questions based on referential condition. The questions presented were grouped and compared based on conceptual complexity with who, what, where categorized as concrete and when, why, how as abstract. Participants answered 89% of concrete and 56% of abstract questions correctly across both conditions. A statistically significant difference between the probability of answering correctly concrete and abstract questions was found. There was also a statistically significant relationship between receptive vocabulary and the probability of answering all questions correctly. Additionally, logistic regression models revealed that receptive vocabulary ability may be more related to answering abstract questions than concrete questions. Analysis of incorrect answers showed that 85% of errors could be meaningfully categorized. Of these responses, 25% were categorically related to the particular wh- question word that was targeted. Further, 10% would have been correct if a different question word was substituted for the target. Additionally, 27% of the responses were related to the topic of the question and the remaining were either I don't know/No responses, repetitions, or unrelated. The categories were generally the same across conditions. Students did, however, produce more of these incorrect responses that were related to the topic in the picture condition. The results of this study point to the importance of learning more about ways to support question comprehension and answering to help individuals with ID answer all types of questions more effectively

S986 in M67: A Totally-Eclipsing Binary at the Cluster Turnoff

We have discovered that the star S986 in the old open cluster M67 has detectable total eclipses of depth 0.08 mag for the primary eclipse and 0.011 mag for the secondary eclipse (in I only). We confirm the detection of a third star in spectra contributing 11.5% +/- 1.5% of the total light in V band. The radial velocity of the third star indicates that it is a cluster member, but it is unclear whether it is physically associated with the eclipsing binary. Using spectroscopic and photometric data, we deconvolve the photometry of the three stars, and find that the primary star in the eclipsing binary is significantly hotter than the turnoff. The two most likely explanations are that the primary star is in a rapid phase of evolution near core hydrogen exhaustion (associated with the turnoff gap in M67's color-magnitude diagram), or that it is a blue straggler created during a stellar collision earlier in the cluster's history. Our detection of Li in the primary star tightly constrains possible formation mechanisms in the blue straggler explanation. Because S986 is often used to constrain tidal dissipation models, this may imply that the strength of tidal effects is underestimated.Comment: 27 pages, 8 figures, accepted for A

Excitonic effects on coherent phonon dynamics in single wall carbon nanotubes

We discuss how excitons can affect the generation of coherent radial breathing modes in ultrafast spectroscopy of single wall carbon nanotubes. Photoexcited excitons can be localized spatially and give rise to a spatially distributed driving force in real space which involves many phonon wavevectors of the exciton-phonon interaction. The equation of motion for the coherent phonons is modeled phenomenologically by the Klein-Gordon equation, which we solve for the oscillation amplitudes as a function of space and time. By averaging the calculated amplitudes per nanotube length, we obtain time-dependent coherent phonon amplitudes that resemble the homogeneous oscillations that are observed in some pump-probe experiments. We interpret this result to mean that the experiments are only able to see a spatial average of coherent phonon oscillations over the wavelength of light in carbon nanotubes and the microscopic details are averaged out. Our interpretation is justified by calculating the time-dependent absorption spectra resulting from the macroscopic atomic displacements induced by the coherent phonon oscillations. The calculated coherent phonon spectra including excitonic effects show the experimentally observed symmetric peaks at the nanotube transition energies in contrast to the asymmetric peaks that would be obtained if excitonic effects were not included.Comment: submitted to Phys. Rev. B on 7 May 2013, revised on 17 July and 13 August 2013, published 30 August 201

The Flipped Classroom Model as Applied to an Augmentative and Alternative Communication Course

The Flipped Classroom Model (FCM) is an andragogical approach where students complete content-related work outside of the class and engage in activities related to this content during the class period. This approach has garnered recent attention in the field of speech-language pathology, but its implementation has not been studied in an augmentative and alternative communication (AAC) course and there is limited information on student perspectives of the experience. This study presents the results of a qualitative investigation designed to investigate the preferences and experiences of preservice speech-language pathology graduate students in an AAC course utilizing the FCM. Semi-structured interviews with eight students were transcribed and analyzed utilizing a phenomenological framework. The themes that emerged from the data included course design, course delivery, instructor characteristics, student preferences, student characteristics, online versus in-person learning, and career relevance. Recommendations for implementing the FCM in teaching AAC are discussed in light of the results presented

Time-Series Photometry of M67: W UMa Systems, Blue Stragglers, and Related Systems

We present an analysis of over 2200 V images taken on 14 nights at the Mt. Laguna 1 m telescope of the open cluster M67. Our observations overlap but extend beyond the field analyzed by Gilliland et al. (1991), and complement data recently published by van den Berg et al. (2002) and Stassun et al. (2002). We show variability in the light curves of all 4 of the known W UMa variables on timescales ranging from a day to decades (for AH Cnc). We have modeled the light curve of AH Cnc, and the total eclipses allow us to determine q = 0.16 +0.03/-0.02 and i = 86 +4/-8 degrees. The position of this system near the turnoff of M67 makes it useful for constraining the turnoff mass for the cluster. We have also detected two unusual features in the light curve of AH Cnc that may be caused by prominences. We have also monitored cluster blue stragglers for variability, and we present evidence hinting at low level variations in the stragglers S752, S968, and S1263, and we place limits on the variability of a number of other cluster blue stragglers. Finally, we provide photometry of the sub-subgiant branch star S1063 showing variability on timescales similar to the orbital period, while the ``red straggler'' S1040 shows evidence of an unexplained drop in brightness at phases corresponding to the passage of the white dwarf in front of the giant.Comment: 44 pages, 16 figures, AASTeX, accepted for A