618 research outputs found
Perceptions of gifted education in middle school and the role of principal
The purpose of this study is to determine the extent to which middle school principals are encouraging particular research-based practices relevant to teaching students with high ability in their buildings. In addition, the study will examine principals\u27 and teachers\u27 perceptions of principal practices related to the improvement in the achievement of gifted students in middle school; The study\u27s design will utilize a mixed method using surveys and interviews. Quantitative methodology will be employed to gain and understanding of the perceptions of principals and teachers through the utilization of the survey. The study will also employ qualitative methodology by interviewing a group of principals and teachers. The population for this study will be all Nevada public middle school (grade 6-8) principals. These participants will be both men and women who are employed as principals in a Nevada public middle school. The population will consist of 129 principals. These middle schools are located in rural, suburban, and urban areas of the state; The study supported the conclusion that, in general, principals are knowledgeable of research-based instructional practices relative to teaching students with high ability. However, teachers do not support the perception of principals that they are encouraging the use of these practices in the classrooms of their buildings. Furthermore, the findings of this study suggest discrepancies between principals\u27 perceived knowledge about research-based instructional practices geared towards students with high ability and their actual pedagogical knowledge
Ultraslow Electron Spin Dynamics in GaAs Quantum Wells Probed by Optically Pumped NMR
Optically pumped nuclear magnetic resonance (OPNMR) measurements were
performed in two different electron-doped multiple quantum well samples near
the fractional quantum Hall effect ground state nu=1/3. Below 0.5K, the spectra
provide evidence that spin-reversed charged excitations of the nu=1/3 ground
state are localized over the NMR time scale of ~40 microseconds. Furthermore,
by varying NMR pulse parameters, the electron spin temperature (as measured by
the Knight shift) could be driven above the lattice temperature, which shows
that the value of the electron spin-lattice relaxation time lies between 100
microseconds and 500 milliseconds at nu=1/3.Comment: 6 pages (REVTEX), 6 eps figures embedded in text; published version;
minor changes to match published versio
History, Policy and Nursing Practice Implications of the Plan B® Emergency Contraceptive
Numerous policy changes have expanded access to emergency contraception, such as Plan B®, in recent years. Plan B® is a progesterone‐based medication that prevents pregnancy from occurring up to 120 hours after unprotected intercourse by preventing ovulation and tubal transport. Increased access to Plan B® allows women to make independent decisions regarding reproductive health. Nurses play an important role in providing education as well as comprehensive, compassionate and holistic care.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111254/1/life12186.pd
Self-consistent propagation of flux ropes in realistic coronal simulations
The aim of this paper is to demonstrate the possible use of the new coronal
model COCONUT to compute a detailed representation of a numerical CME at
0.1~AU, after its injection at the solar surface and propagation in a realistic
solar wind, as derived from observed magnetograms. We present the
implementation and propagation of modified Titov-D\'emoulin (TDm) flux ropes in
the COCONUT 3D MHD coronal model. The background solar wind is reconstructed in
order to model two opposite configurations representing a solar activity
maximum and minimum respectively. Both were derived from magnetograms which
were obtained by the Helioseismic and Magnetic Imager (HMI) onboard the Solar
Dynamic Observatory (SDO) satellite. We track the propagation of 24 flux ropes,
which differ only by their initial magnetic flux. We especially investigate the
geometry of the flux rope during the early stages of the propagation as well as
the influence of its initial parameters and solar wind configuration on 1D
profiles derived at 0.1~AU. At the beginning of the propagation, the shape of
the flux ropes varies between simulations during low and high solar activity.
We find dynamics that are consistent with the standard CME model, such as the
pinching of the legs and the appearance of post-flare loops. Despite the
differences in geometry, the synthetic density and magnetic field time profiles
at 0.1~AU are very similar in both solar wind configurations. These profiles
are similar to those observed further in the heliosphere and suggest the
presence of a magnetic ejecta composed of the initially implemented flux rope
and a sheath ahead of it. Finally, we uncover relationships between the
properties of the magnetic ejecta, such as density or speed and the initial
magnetic flux of our flux ropes.Comment: 20 pages, 13 figure
Normalization of drug and therapeutic concepts with Thera-Py
OBJECTIVE: The diversity of nomenclature and naming strategies makes therapeutic terminology difficult to manage and harmonize. As the number and complexity of available therapeutic ontologies continues to increase, the need for harmonized cross-resource mappings is becoming increasingly apparent. This study creates harmonized concept mappings that enable the linking together of like-concepts despite source-dependent differences in data structure or semantic representation.
MATERIALS AND METHODS: For this study, we created Thera-Py, a Python package and web API that constructs searchable concepts for drugs and therapeutic terminologies using 9 public resources and thesauri. By using a directed graph approach, Thera-Py captures commonly used aliases, trade names, annotations, and associations for any given therapeutic and combines them under a single concept record.
RESULTS: We highlight the creation of 16 069 unique merged therapeutic concepts from 9 distinct sources using Thera-Py and observe an increase in overlap of therapeutic concepts in 2 or more knowledge bases after harmonization using Thera-Py (9.8%-41.8%).
CONCLUSION: We observe that Thera-Py tends to normalize therapeutic concepts to their underlying active ingredients (excluding nondrug therapeutics, eg, radiation therapy, biologics), and unifies all available descriptors regardless of ontological origin
Spectroscopic Evidence for the Localization of Skyrmions near Nu=1 as T->0
Optically pumped nuclear magnetic resonance measurements of Ga-71 spectra
were carried out in an n-doped GaAs/Al0.1Ga0.9As multiple quantum well sample
near the integer quantum Hall ground state Nu=1. As the temperature is lowered
(down to T~0.3 K), a ``tilted plateau'' emerges in the Knight shift data, which
is a novel experimental signature of quasiparticle localization. The dependence
of the spectra on both T and Nu suggests that the localization is a collective
process. The frozen limit spectra appear to rule out a 2D lattice of
conventional skyrmions.Comment: 4 pages (REVTEX), 5 eps figures embedded in text, published versio
Fast Matrix Multiplication via Compiler-only Layered Data Reorganization and Intrinsic Lowering
The resurgence of machine learning has increased the demand for
high-performance basic linear algebra subroutines (BLAS), which have long
depended on libraries to achieve peak performance on commodity hardware.
High-performance BLAS implementations rely on a layered approach that consists
of tiling and packing layers, for data (re)organization, and micro kernels that
perform the actual computations. The creation of high-performance micro kernels
requires significant development effort to write tailored assembly code for
each architecture. This hand optimization task is complicated by the recent
introduction of matrix engines by IBM's POWER10 MMA, Intel AMX, and Arm ME to
deliver high-performance matrix operations. This paper presents a compiler-only
alternative to the use of high-performance libraries by incorporating, to the
best of our knowledge and for the first time, the automatic generation of the
layered approach into LLVM, a production compiler. Modular design of the
algorithm, such as the use of LLVM's matrix-multiply intrinsic for a clear
interface between the tiling and packing layers and the micro kernel, makes it
easy to retarget the code generation to multiple accelerators. The use of
intrinsics enables a comprehensive performance study. In processors without
hardware matrix engines, the tiling and packing delivers performance up to 22x
(Intel), for small matrices, and more than 6x (POWER9), for large matrices,
faster than PLuTo, a widely used polyhedral optimizer. The performance also
approaches high-performance libraries and is only 34% slower than OpenBLAS and
on-par with Eigen for large matrices. With MMA in POWER10 this solution is, for
large matrices, over 2.6x faster than the vector-extension solution, matches
Eigen performance, and achieves up to 96% of BLAS peak performance
Observation of a new phase transition between fully and partially polarized quantum Hall states with charge and spin gaps at
The average electron spin-polarization of two-dimensional electron
gas confined in multiple quantum-wells was measured by
nuclear magnetic resonance (NMR) near the fractional quantum Hall state with
filling factor . Above this filling factor (), a strong depolarization is observed corresponding to two spin flips per
additional flux quantum. The most remarkable behavior of the polarization is
observed at , where a quantum phase transition from a partially
polarized () to a fully polarized ()
state can be driven by increasing the ratio between the Zeeman and the Coulomb
energy above a critical value .Comment: 4 pages including 4 figure
NMR Determination of 2D Electron Spin Polarization at
Using a `standard' NMR spin-echo technique we determined the spin
polarization of two-dimensional electrons, confined to GaAs quantum wells, from
the hyperfine shift of Ga nuclei in the wells. Concentrating on the temperature
and magnetic field dependencies of spin polarization at Landau level filling
factor , we find that the results are described well by a simple
model of non-interacting composite fermions, although some inconsistencies
remain when the two-dimensional electron system is tilted in the magnetic
field.Comment: 4 pages (REVTEX) AND 4 figures (PS
Tunneling into Ferromagnetic Quantum Hall States: Observation of a Spin Bottleneck
We explore the characteristics of equilibrium tunneling of electrons from a
3D electrode into a high mobility 2D electron system. For most 2D Landau level
filling factors, we find that tunneling can be characterized by a single,
well-defined tunneling rate. However, for spin-polarized quantum Hall states
(nu = 1, 3 and 1/3) tunneling occurs at two distinct rates that differ by up to
2 orders of magnitude. The dependence of the two rates on temperature and
tunnel barrier thickness suggests that slow in-plane spin relaxation creates a
bottleneck for tunneling of electrons.Comment: 5 pages, 4 figures, submitted to PR
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