1,843 research outputs found
Interpreting feedback: a discourse analysis of teacher feedback and student identity
Feedback has typically been studied as a means of improving academic performance. Few studies inquire into the processes by which feedback shapes student identity. The authors carry out a discourse analysis of written comments to explore how feedback is discursively constructed by both teachers and students. Analysis of written feedback, think-aloud protocols, and semi-structured interviews work to arrive at an understanding of how feedback is interpreted by both teachers and students, paying special attention to how such interpretations contribute to a student’s identity. The following themes emerged as likely interpretations: feedback as a discourse of correction, feedback as a set of ontological metaphors, and feedback as a process of rhetorical listening. The discourse analysis reveals that while teachers tend to interpret feedback as a means of correcting a student’s text, students’ interpretations of feedback contribute to the construction of their selves. Reflecting on these results, the authors suggest teachers construct feedback as a personal conversation that remains sensitive to the immediate personal effects on students
Using APOGEE Wide Binaries to Test Chemical Tagging with Dwarf Stars
Stars of a common origin are thought to have similar, if not nearly
identical, chemistry. Chemical tagging seeks to exploit this fact to identify
Milky Way subpopulations through their unique chemical fingerprints. In this
work, we compare the chemical abundances of dwarf stars in wide binaries to
test the abundance consistency of stars of a common origin. Our sample of 31
wide binaries is identified from a catalog produced by cross-matching APOGEE
stars with UCAC5 astrometry, and we confirm the fidelity of this sample with
precision parallaxes from Gaia DR2. For as many as 14 separate elements, we
compare the abundances between components of our wide binaries, finding they
have very similar chemistry (typically within 0.1 dex). This level of
consistency is more similar than can be expected from stars with different
origins (which show typical abundance differences of 0.3-0.4 dex within our
sample). For the best measured elements, Fe, Si, K, Ca, Mn, and Ni, these
differences are reduced to 0.05-0.08 dex when selecting pairs of dwarf stars
with similar temperatures. Our results suggest that APOGEE dwarf stars may
currently be used for chemical tagging at the level of 0.1 dex or at the
level of 0.05 dex when restricting for the best-measured elements in
stars of similar temperatures. Larger wide binary catalogs may provide
calibration sets, in complement to open cluster samples, for on-going
spectroscopic surveys.Comment: 21 pages, 14 figures, accepted for publication in Ap
A model for two-proton emission induced by electron scattering
A model to study two-proton emission processes induced by electron scattering
is developed. The process is induced by one-body electromagnetic operators
acting together with short-range correlations, and by two-body
currents. The model includes all the diagrams containing a single correlation
function. A test of the sensitivity of the model to the various theoretical
inputs is done. An investigation of the relevance of the currents is
done by changing the final state angular momentum, excitation energy and
momentum transfer. The sensitivity of the cross section to the details of the
correlation function is studied by using realistic and schematic correlations.
Results for C, O and Ca nuclei are presented.Comment: 30 pages, 18 figures, 3 table
Accounting for preemption and migration costs in the calculation of hard real-time cyclic executives for MPSoCs
This work introduces a methodology to consider preemption and migration overhead in hard real-time cyclic executives on multicore architectures. The approach performs two iterative stages. The first stage takes a cyclic executive, from which the number and timing of all preemptions and migrations for every task is known. Then, it includes this overhead by updating the worst-case execution time (WCET) of the tasks. The second stage calculates a new cyclic executive considering the new WCET of tasks. The stages iterate until the preemption and migration overhead keeps constant. © 2016 IEEE
Superscaling in electroweak excitation of nuclei
Superscaling properties of 12C, 16O and 40Ca nuclear responses, induced by
electron and neutrino scattering, are studied for momentum transfer values
between 300 and 700 MeV/c. We have defined two indexes to have quantitative
estimates of the scaling quality. We have analyzed experimental responses to
get the empirical values of the two indexes. We have then investigated the
effects of finite dimensions, collective excitations, meson exchange currents,
short-range correlations and final state interactions. These effects strongly
modify the relativistic Fermi gas scaling functions, but they conserve the
scaling properties. We used the scaling functions to predict electron and
neutrino cross sections and we tested their validity by comparing them with the
cross sections obtained with a full calculation. For electron scattering we
also made a comparison with data. We have calculated the total charge-exchange
neutrino cross sections for neutrino energies up to 300 MeV.Comment: 19 pages, 12 figures, 1 table; to be published in Physical Review
Magnetic excitations in nuclei with neutron excess
The excitation of the , and modes in O, O,
O, O, Ca, Ca, Ca and Ca nuclei is
studied with self-consistent random phase approximation calculations.
Finite-range interactions of Gogny type, containing also tensor-isospin terms,
are used. We analyze the evolution of the magnetic resonances with the
increasing number of neutrons, the relevance of collective effects, the need of
a correct treatment of the continuum and the role of the tensor force.Comment: 18 pages, 12 figures, 2 tables, accepted for publication in Physical
Review
Multiple shape coexistence in the nucleus Zr
We study the low-lying energy spectrum of the rp-process waiting point
nucleus 80Zr with state-of-the-art beyond mean field methods with the Gogny D1S
interaction. Symmetry restoration and configuration mixing of axial and
triaxial shapes are included in the calculations. Five 0+ states corresponding
to different nuclear shapes are obtained below 2.25 MeV and several rotational
and {\gamma}- bands built upon them are identified. Nevertheless, these states
do not modify the {\beta}-decay half-life having a negligible effect in the
rp-process. A good agreement with the available experimental data is obtained.Comment: 6 pages, 3 figures, submitted to Physics Letters
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