4,104 research outputs found
Assessing the language of chat for teamwork dialogue
In technology enhanced language learning, many pedagogical activities involve students in online discussion such as synchronous chat, in order to help them practice their language skills. Besides developing the language competency of students, it is also crucial to nurture their teamwork competencies for today's global and complex environment. Language communication is an important glue of teamwork. In order to assess the language of chat for teamwork dimensions, several text mining methods are pos sible. However, difficulties arise such as pre-processing being a black box and classification approaches and algorithms being dependent on the context. To address these issues, the study will evaluate and explain preprocessing and classification methods used to analyze teamwork dialogue from a dataset of chat data. Analytics methods evaluated in this study provide a direction for assessing the language of chat for teamwork dialogue and can help extend the work of technology enhanced language learning to n ot only focus on academic competency, but on the communication aspect too
Effects of electronic correlation on X-Ray absorption and dichroic spectra at L edge
We present a new theoretical approach to describe X-Ray absorption and
Magnetic Circular Dichroism spectra in the presence of e-e correlation. Our
approach provides an unified picture to include correlations in both charged
and neutral excitations, namely in direct / inversion photoemission where
electrons are removed/added, and photo absorption where electrons are promoted
from core levels to empty states. We apply this approach to the prototypical
case of L edge of 3 transition metals and we show that the inclusion
of many body effects in the core level excitations is essential to reproduce,
together with satellite structures in core level photoemission, the observed
asymmetric line shapes in X-ray absorption and dichroic spectra.Comment: 3 figures, 5 pages, submitted to Phys. Rev.
High-gain nonlinear observer for simple genetic regulation process
High-gain nonlinear observers occur in the nonlinear automatic control theory
and are in standard usage in chemical engineering processes. We apply such a
type of analysis in the context of a very simple one-gene regulation circuit.
In general, an observer combines an analytical differential-equation-based
model with partial measurement of the system in order to estimate the
non-measured state variables. We use one of the simplest observers, that of
Gauthier et al., which is a copy of the original system plus a correction term
which is easy to calculate. For the illustration of this procedure, we employ a
biological model, recently adapted from Goodwin's old book by De Jong, in which
one plays with the dynamics of the concentrations of the messenger RNA coding
for a given protein, the protein itself, and a single metabolite. Using the
observer instead of the metabolite, it is possible to rebuild the non-measured
concentrations of the mRNA and the proteinComment: 9 pages, one figur
Visible-Light-Driven Photocatalytic Activity of SnO2-ZnO Quantum Dots Anchored on g-C3N4 Nanosheets for Photocatalytic Pollutant Degradation and H-2 Production
A zero-dimensional/two-dimensional heterostructure consists of binary SnO2-ZnO quantum dots (QDs) deposited on the surface of graphitic carbon nitride (g-C3N4) nanosheets. The so-called SnO2-ZnO QDs/g-C3N4 hybrid was successfully synthesized via an in situ co-pyrolysis approach to achieve efficient photoactivity for the degradation of pollutants and production of hydrogen (H-2) under visible-light irradiation. High-resolution transmission electron microscopy images show the close contacts between SnO2-ZnO QDs with the g-C3N4 in the ternary SnO2-ZnO QDs/g-C3N4 hybrid. The optimized hybrid shows excellent photocatalytic efficiency, achieving 99% rhodamine B dye degradation in 60 min under visible-light irradiation. The enriched charge-carrier separation and transportation in the SnO2-ZnO QDs/g-C3N4 hybrid was determined based on electrochemical impedance and photocurrent analyses. This remarkable photoactivity is ascribed to the "smart" heterostructure, which yields numerous benefits, such as visible-light-driven fast electron and hole transfer, due to the strong interaction between the SnO2-ZnO QDs with the g-C3N4 matrix. In addition, the SnO2-ZnO QDs/g-C3N4 hybrid demonstrated a high rate of hydrogen production (13 673.61 mu mol g(-1)), which is 1.06 and 2.27 times higher than that of the binary ZnO/g-C3N4 hybrid (12 785.54 mu mol g(-1)) and pristine g-C3N4 photocatalyst (6017.72 mu mol g(-1)). The synergistic effect of increased visible absorption and diminished recombination results in enhanced performance of the as-synthesized tin oxide-and zinc oxide-modified g-C3N4. We conclude that the present ternary SnO2-ZnO QDs/g-C3N4 hybrid is a promising electrode material for H-2 production and photoelectrochemical cells
Spin-Orbit Interactions in Bilayer Exciton-Condensate Ferromagnets
Bilayer electron-hole systems with unequal electron and hole densities are
expected to have exciton condensate ground states with spontaneous
spin-polarization in both conduction and valence bands. In the absence of
spin-orbit and electron-hole exchange interactions there is no coupling between
the spin-orientations in the two quantum wells. In this article we show that
Rashba spin-orbit interactions lead to unconventional magnetic anisotropies,
whose strength we estimate, and to ordered states with unusual quasiparticle
spectra.Comment: 36 pages, 12 figure
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