4,751 research outputs found
African American English And Urban Literature: Creating Culturally Caring Classrooms
Language and literacy are a means of delivering care through consideration of students’ home culture; however, a cultural mismatch between the predominantly white, female educator population and the diverse urban student population is reflected in language and literacy instruction. Urban curricula often fail to incorporate culturally relevant literature, in part due to a dearth of texts that reflect student experiences. Dialectal differences between African American English (AAE) and Mainstream American English (MAE) and a history of racism have attached a reformatory stigma to AAE and its speakers. The authors assert that language and literacy instruction that validates children’s lived experience mediates this hegemony, leads to empathetic relationships between teachers and students of different cultural backgrounds, and promotes academic success. This paper seeks to 1) dissect the relationship between academic achievement and affirmation of student culture through language and literacy instruction, 2) enumerate classroom strategies that empower students and foster the development of self-efficacy 3) identify ways teachers might weave value for diversity in language and literacy into a pedagogy of care for urban classrooms
A conservative approach to parallelizing the Sharks World simulation
Parallelizing a benchmark problem for parallel simulation, the Sharks World, is described. The described solution is conservative, in the sense that no state information is saved, and no 'rollbacks' occur. The used approach illustrates both the principal advantage and principal disadvantage of conservative parallel simulation. The advantage is that by exploiting lookahead an approach was found that dramatically improves the serial execution time, and also achieves excellent speedups. The disadvantage is that if the model rules are changed in such a way that the lookahead is destroyed, it is difficult to modify the solution to accommodate the changes
Magneto-optical conductivity in graphene including electron-phonon coupling
We show how coupling to an Einstein phonon affects the absorption
peaks seen in the optical conductivity of graphene under a magnetic field .
The energies and widths of the various lines are shifted, and additional peaks
arise in the spectrum. Some of these peaks are Holstein sidebands, resulting
from the transfer of spectral weight in each Landau level (LL) into
phonon-assisted peaks in the spectral function. Other additional absorption
peaks result from transitions involving split LLs, which occur when a LL falls
sufficiently close to a peak in the self-energy. We establish the selection
rules for the additional transitions and characterize the additional absorption
peaks. For finite chemical potential, spectral weight is asymmetrically
distributed about the Dirac point; we discuss how this causes an asymmetry in
the transitions due to left- and right-handed circularly polarized light and
therefore oscillatory behavior in the imaginary part of the off-diagonal Hall
conductivity. We also find that the semiclassical cyclotron resonance region is
renormalized by an effective-mass factor but is not directly affected by the
additional transitions. Last, we discuss how the additional transitions can
manifest in broadened, rather than split, absorption peaks due to large
scattering rates seen in experiment.Comment: 24 pages, 21 figure
Phonon structures in the electronic density of states of graphene in magnetic field
Unlike in ordinary metals, in graphene, phonon structure can be seen in the
quasiparticle electronic density of states, because the latter varies on the
scale of the phonon energy. In a magnetic field, quantization into Landau
levels creates even more significant variations. We calculate the density of
states incorporating electron-phonon coupling in this case and find that the
coupling has pronounced new effects: shifting and broadening of Landau levels,
creation of new peaks, and splitting of any Landau levels falling near one of
the new peaks. Comparing our calculations with a recent experiment, we find
evidence for a phonon with energy similar to but somewhat greater than the
optical mode and a coupling corresponding to a mass enhancement
parameter .Comment: 6 pages, 4 figures, final version to be published in EP
Ultrasonic attenuation in clean d-wave superconductors
We consider the attenuation of longitudinal ultrasonic waves in a clean
two-dimensional d-wave superconductor. We show that the attenuation coefficient
is linear in temperature at low temperatures for all in-plane directions of the
propagation of the ultrasound, and that the coefficient of the linear term can
be used to determine the parameters crucial for the low temperature transport
in these compounds.Comment: 4 pages, very minor changes, published versio
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