2,889 research outputs found
Enhancing Learning Outcomes in an Intervention Based Orthopedic Course
This capstone project was completed through a collaboration with Belmont University’s School of Occupational Therapy in Nashville, Tennessee. The project focused on reviewing, creating, and implementing supplemental educational material to enhance learning outcomes in first year OTD students in the occupational performance I course (OPI). OPI is the first intervention-based course in the curriculum, focusing on the orthopedic and acute care settings. The educational material created includes five video demonstrations, three comprehensive case studies and videos of the evaluation and treatment sessions that coincide, four review sessions of important topics covered in lecture, and multiple fabricated orthotics. A pre and posttest Likert scale gauging student confidence in their knowledge and performance of the topic was administered for each review session. Statistical analysis of the data using a paired two sample t-test was completed and suggest there is a significant improvement in student knowledge and performance after each review session
Gap Anisotropy and de Haas-van Alphen Effect in Type-II Superconductors
We present a theoretical study on the de Haas-van Alphen (dHvA) oscillation
in the vortex state of type-II superconductors, with a special focus on the
connection between the gap anisotropy and the oscillation damping. Numerical
calculations for three different gap structures clearly indicate that the
average gap along extremal orbits is relevant for the magnitude of the extra
damping, thereby providing a support for experimental efforts to probe gap
anisotropy through the dHvA signal. We also derive an analytic formula for the
extra damping which gives a good fit to the numerical results.Comment: 5 pages, 1 figure, changes in Introductio
Properties of Nambu-Goldstone Bosons in a Single-Component Bose-Einstein Condensate
We theoretically study the properties of Nambu-Goldstone bosons in an
interacting single-component Bose-Einstein condensate (BEC). We first point out
that the proofs of Goldstone's theorem by Goldstone, et al. [Phys. Rev. {\bf
127} (1962) 965] may be relevant to distinct massless modes of the BEC: whereas
the first proof deals with the poles of the single-particle Green's function
, the second one concerns those of the two-particle Green's function.
Thus, there may be multiple Nambu-Goldstone bosons even in the single-component
BEC with broken U(1) symmetry. The second mode turns out to have an infinite
lifetime in the long-wavelength limit in agreement with the conventional
viewpoint. In contrast, the first mode from , i.e., the Bogoliubov
mode in the weak-coupling regime, is shown to be a "bubbling" mode fluctuating
temporally out of and back into the condensate. The substantial lifetime
originates from an "improper" structure of the self-energy inherent in the BEC,
which has been overlooked so far and will be elucidated here, and removes
various infrared divergences pointed out previously.Comment: 9 pages, 6 gigure
Oxygen-isotope and trace element constraints on the origins of silica-rich melts in the subarc mantle
Peridotitic xenoliths in basaltic andesites from Batan island in the Luzon arc contain silica-rich (broadly dacitic) hydrous melt inclusions that were likely trapped when these rocks were within the upper mantle wedge underlying the arc. These melt inclusions have been previously interpreted to be slab-derived melts. We tested this hypothesis by analyzing the oxygen isotope compositions of these inclusions with an ion microprobe. The melt inclusions from Batan xenoliths have δ 18OVSMOW values of 6.45 ± 0.51‰. These values are consistent with the melts having been in oxygen isotope exchange equilibrium with average mantle peridotite at temperatures of ≥875°C. We suggest the δ 18O values of Batan inclusions, as well as their major and trace element compositions, can be explained if they are low-degree melts (or differentiation products of such melts) of peridotites in the mantle wedge that had previously undergone extensive melt extraction followed by metasomatism by small amounts (several percent or less) of slab-derived components. A model based on the trace element contents of Batan inclusions suggests that this metasomatic agent was an aqueous fluid extracted from subducted basalts and had many characteristics similar to slab-derived components of the sources of arc-related basalts at Batan and elsewhere. Batan inclusions bear similarities to “adakites,” a class of arc-related lava widely considered to be slab-derived melts. Our results suggest the alternative interpretation that at least some adakite-like liquids might be generated from low-degree melting of metasomatized peridotites
Spatially resolved electronic structure of an isovalent nitrogen center in GaAs
Small numbers of nitrogen dopants dramatically modify the electronic
properties of GaAs, generating very large shifts in the conduction-band
energies with nonlinear concentration dependence, and impurity-associated
spatially-localized resonant states within the conduction band. Cross-sectional
scanning tunneling microscopy provides the local electronic structure of single
nitrogen dopants at the (110) GaAs surface, yielding highly anisotropic spatial
shapes when the empty states are imaged. Measurements of the resonant states
relative to the GaAs surface states and their spatial extent allow an
unambiguous assignment of specific features to nitrogen atoms at different
depths below the cleaved (110) surface. Multiband tight binding calculations
around the resonance energy of nitrogen in the conduction band match the imaged
features. The spatial anisotropy is attributed to the tetrahedral symmetry of
the bulk lattice. Additionally, the voltage dependence of the electronic
contrast for two features in the filled state imaging suggest these features
could be related to a locally modified surface state
Reactivity difference between protolytic forms of some macrocyclic chromium(III) complexes in ligand substitution and electron transfer processes
The review provides insight into the mechanism of ligand substitution and electron transfer (from chromium( III) to iron(III)) by comparison of the reactivity of some tetraazamacrocyclic chromium(III) complexes in the conjugate acid-base forms. Use of two geometrical isomers made possible to estimate the influence of geometry and protolytic reactions in trans and cis position towards the leaving group on the rate enhancement. Studies on the reaction rates in different media demonstrated the role played by outer sphere interactions in a monodentate ligand substitution
Self-Consistent Approximations for Superconductivity beyond the Bardeen-Cooper-Schrieffer Theory
We develop a concise self-consistent perturbation expansion for
superconductivity where all the pair processes are naturally incorporated
without drawing "anomalous" Feynman diagrams. This simplification results from
introducing an interaction vertex that is symmetric in the particle-hole
indices besides the ordinary space-spin coordinates. The formalism
automatically satisfies conservation laws, includes the Luttinger-Ward theory
as the normal-state limit, and reproduces the Bardeen-Cooper-Schrieffer theory
as the lowest-order approximation. It enables us to study the thermodynamic,
single-particle, two-particle, and dynamical properties of superconductors with
competing fluctuations based on a single functional of Green's
function in the Nambu space. Specifically, we derive closed equations
in the FLEX-S approximation, i.e., the fluctuation exchange approximation for
superconductivity with all the pair processes, which contains extra terms
besides those in the standard FLEX approximation.Comment: 14 pages, 6 figure
Exact results on the two-particle Green's function of a Bose-Einstein condensate
Starting from the Dyson-Beliaev and generalized Gross-Pitaevskii equations
with an extra nonlocal potential, we derive an exact expression of the
two-particle Green's function K for an interacting Bose-Einstein condensate in
terms of unambiguously defined self-energies and vertices. The formula can be a
convenient basis for approximate calculations of K. It also tells us that poles
of K are not shared with (i.e. shifted from) those of the single-particle
Green's function, contrary to the conclusion of previous studies.Comment: 5 pages, 2 figures, to appear in Phys. Rev.
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