1,621 research outputs found
New and Developing Research on Disparities in Discipline
This briefing paper describes the results of new research in the area of disciplinary disparities, and identifies remaining gaps in the literature that can guide researchers and funders of research. The brief is organized into two sections:1) What Have we Learned? Key New Research Findings describes research from leading scholars across the nation commissioned by The Center for Civil Rights Remedies at UCLA's Civil Rights Project with the support of the Collaborative, findings from projects supported by the Collaborative Funded Research Grant Program, and other new research on disproportionality in school discipline in the peer-reviewed literature.2) Future Research Needs describes gaps that remain in the research base. Although there has been considerable new knowledge generated in recent years, significant gaps remain, especially in identifying and evaluating intervention strategies that reduce inequity in discipline for all students
Overhauser effect in individual InP/GaInP dots
Sizable nuclear spin polarization is pumped in individual InP/GaInP dots in a
wide range of external magnetic fields B_ext=0-5T by circularly polarized
optical excitation. We observe nuclear polarization of up to ~40% at Bext=1.5T
and corresponding to an Overhauser field of ~1.2T. We find a strong feedback of
the nuclear spin on the spin pumping efficiency. This feedback, produced by the
Overhauser field, leads to nuclear spin bi-stability at low magnetic fields of
Bext=0.5-1.5T. We find that the exciton Zeeman energy increases markedly, when
the Overhauser field cancels the external field. This counter-intuitive result
is shown to arise from the opposite contribution of the electron and hole
Zeeman splittings to the total exciton Zeeman energy
Voltage controlled nuclear polarization switching in a single InGaAs quantum dot
Sharp threshold-like transitions between two stable nuclear spin
polarizations are observed in optically pumped individual InGaAs self-assembled
quantum dots embedded in a Schottky diode when the bias applied to the diode is
tuned. The abrupt transitions lead to the switching of the Overhauser field in
the dot by up to 3 Tesla. The bias-dependent photoluminescence measurements
reveal the importance of the electron-tunneling-assisted nuclear spin pumping.
We also find evidence for the resonant LO-phonon-mediated electron
co-tunneling, the effect controlled by the applied bias and leading to the
reduction of the nuclear spin pumping rate.Comment: 5 pages, 2 figures, submitted to Phys Rev
Overhauser effect in individual InP/GaInP dots
Sizable nuclear spin polarization is pumped in individual InP/GaInP dots in a
wide range of external magnetic fields B_ext=0-5T by circularly polarized
optical excitation. We observe nuclear polarization of up to ~40% at Bext=1.5T
and corresponding to an Overhauser field of ~1.2T. We find a strong feedback of
the nuclear spin on the spin pumping efficiency. This feedback, produced by the
Overhauser field, leads to nuclear spin bi-stability at low magnetic fields of
Bext=0.5-1.5T. We find that the exciton Zeeman energy increases markedly, when
the Overhauser field cancels the external field. This counter-intuitive result
is shown to arise from the opposite contribution of the electron and hole
Zeeman splittings to the total exciton Zeeman energy
Summary of updates to the 2021 European Society of Cardiology Guidelines for the diagnosis and treatment of acute and chronic heart failure
The article provides a summary of the 2021 European Society of Cardiology (ESC) Guidelines for the diagnosis and treatment of acute and chronic heart failure (CHF). The most significant changes for general practitioners, internists and primary care cardiologists, from our point of view, regards etiology, terminology, as well as algorithms for diagnosing and treating CHF in accordance with phenotypes, new indications to a number of drugs, in particular sodium-glucose cotransporter type 2 inhibitors (dapagliflozin and empagliflozin) with assignment of class I recommended therapy and vericiguat. The article discusses the diagnostic criteria for different heart failure phenotypes, the potential of treating patients with heart failure mildly reduced and preserved ejection fraction
Suppression of nuclear spin diffusion at a GaAs/AlGaAs interface measured with a single quantum dot nano-probe
Nuclear spin polarization dynamics are measured in optically pumped
individual GaAs/AlGaAs interface quantum dots by detecting the time-dependence
of the Overhauser shift in photoluminescence (PL) spectra. Long nuclear
polarization decay times of ~ 1 minute have been found indicating inefficient
nuclear spin diffusion from the GaAs dot into the surrounding AlGaAs matrix in
externally applied magnetic field. A spin diffusion coefficient two orders
lower than that previously found in bulk GaAs is deduced.Comment: 5 pages, 3 figures, submitted to Phys Rev
A Systematic Approach to Confinement in N=1 Supersymmetric Gauge Theories
We give necessary criteria for N=1 supersymmetric theories to be in a
smoothly confining phase without chiral symmetry breaking and with a
dynamically generated superpotential. Using our general arguments we find all
such confining SU and Sp theories with a single gauge group and no tree level
superpotential.Comment: 8 pages, LaTe
Superembedding methods for 4d N=1 SCFTs
We extend SO(4,2) covariant lightcone embedding methods of four-dimensional
CFTs to N=1 superconformal field theory (SCFT). Manifest superconformal
SU(2,2|1) invariance is achieved by realizing 4D superconformal space as a
surface embedded in the projective superspace spanned by certain complex chiral
supermatrices. Because SU(2,2|1) acts linearly on the ambient space, the
constraints on correlators implied by superconformal Ward identities are
automatically solved in this formalism. Applications include new, compact
expressions for correlation functions containing one anti-chiral superfield and
arbitrary chiral superfield insertions, and manifestly invariant expressions
for the superconformal cross-ratios that parametrize the four-point function of
two chiral and two anti-chiral fields. Superconformal expressions for the
leading singularities in the OPE of chiral and anti-chiral operators are also
given. Because of covariance, our expressions are valid in any superconformally
flat background, e.g., AdS_4 or R times S^3.Comment: 33 pages, clarification of constraints, version to appear in PR
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