Characterization of recombination and control electrodes for spacecraft nickel- cadmium cells

Characterization of recombination and control electrodes for spacecraft nickel cadmium cell

Correlations, fluctuations and stability of a finite-size network of coupled oscillators

The incoherent state of the Kuramoto model of coupled oscillators exhibits marginal modes in mean field theory. We demonstrate that corrections due to finite size effects render these modes stable in the subcritical case, i.e. when the population is not synchronous. This demonstration is facilitated by the construction of a non-equilibrium statistical field theoretic formulation of a generic model of coupled oscillators. This theory is consistent with previous results. In the all-to-all case, the fluctuations in this theory are due completely to finite size corrections, which can be calculated in an expansion in 1/N, where N is the number of oscillators. The N -> infinity limit of this theory is what is traditionally called mean field theory for the Kuramoto model.Comment: 25 pages (2 column), 12 figures, modifications for resubmissio

Sphaleron Effects Near the Critical Temperature

We discuss one-loop radiative corrections to the sphaleron-induced baryon number-violating transition rate near the electroweak phase transition in the standard model. We emphasize that in the case of a first-order transition a rearrangement of the loop expansion is required close to the transition temperature. The corresponding expansion parameter, the effective 3-dimensional gauge coupling approaches a finite $\lambda$ dependent value at the critical temperature. The $\lambda$ (Higgs mass) dependence of the 1-loop radiative corrections is discussed in the framework of the heat kernel method. Radiative corrections are small compared to the leading sphaleron contribution as long as the Higgs mass is small compared to the W mass. To 1-loop accuracy, there is no Higgs mass range compatible with experimental limits where washing-out of a B+L asymmetry could be avoided for the minimal standard model with one Higgs doublet.Comment: 17 pages, RevTeX, (4 figures in a separate uuencoded file), HD-THEP-93-23re

Mass splittings of nuclear isotopes in chiral soliton approach

The differences of the masses of nuclear isotopes with atomic numbers between \~10 and ~30 can be described within the chiral soliton approach in satisfactory agreement with data. Rescaling of the model is necessary for this purpose - decrease of the Skyrme constant by about 30%, providing the "nuclear variant" of the model. The asymmetric term in Weizsaecker-Bethe- Bacher mass formula for nuclei can be obtained as the isospin dependent quantum correction to the nucleus energy. Some predictions for the binding energies of neutron rich nuclides are made in this way, from, e.g. Be-16 and B-19 to Ne-31 and Na-32. Neutron rich nuclides with high values of isospin are unstable relative to strong interactions. The SK4 (Skyrme) variant of the model, as well as SK6 variant (6-th order term in chiral derivatives in the lagrangian as solitons stabilizer) are considered, and the rational map approximation is used to describe multiskyrmions.Comment: 16 pages, 10 tables, 2 figures. Figures are added and few misprints are removed. Submitted to Phys. Atom. Nucl. (Yad. Fiz.

Semiclassical quantization of SU(3) skyrmions

Semiclassical quantization of the SU(3)-skyrmions is performed by means of the collective coordinate method. The quantization condition known for the SU(2)-solitons quantized with SU(3) collective coordinates is generalized for the SU(3) skyrmions with strangeness content different from zero. Quantization of the dipole-type configuration with large strangeness content found recently is considered as an example, the spectrum and the mass splitting of the quantized states are estimated. The energy and baryon number density of SU(3) skyrmions are presented in the form emphasizing their symmetry in different SU(2) subgroups of SU(3), and the lower boundary for the static energy of SU(3) skyrmions is derived.Comment: 16 pages, 2 figures (available upon request). Submitted to JETP on May 6, 1997; in print. A preliminary short version of this paper is hep-th/960916

A better start to literacy learning: findings from a teacher-implemented intervention in children’s first year at school

CAUL read and publish agreementThis study investigated the feasibility of a teacher implemented intervention to accelerate phonological awareness, letter, and vocabulary knowledge in 141 children (mean age 5 years, 4 months) who entered school with lower levels of oral language ability. The children attended schools in low socioeconomic communities where additional stress was still evident 6 years after the devastating earthquakes in Christchurch, New Zealand in 2011. The teachers implemented the intervention at the class or large group level for 20 h (four 30-min sessions per week for 10 weeks). A stepped wedge research design was used to evaluate intervention effects. Children with lower oral language ability made significantly more progress in both their phonological awareness and targeted vocabulary knowledge when the teachers implemented the intervention compared to progress made when teachers implemented their usual literacy curriculum. Importantly, the intervention accelerated children’s ability to use improved phonological awareness skills when decoding novel words (treatment effect size d = 0.88). Boys responded to the intervention as well as girls and the skills of children who identified as Māori or Pacific Islands (45.5% of the cohort) improved in similar ways to children who identified as New Zealand European. The findings have important implications for designing successful teacher-implemented interventions, within a multi-tier approach, to support children who enter school with known challenges for their literacy learning.fals

Parsimonious continuous time random walk models and kurtosis for diffusion in magnetic resonance of biological tissue

In this paper, we provide a context for the modeling approaches that have been developed to describe non-Gaussian diffusion behavior, which is ubiquitous in diffusion weighted magnetic resonance imaging of water in biological tissue. Subsequently, we focus on the formalism of the continuous time random walk theory to extract properties of subdiffusion and superdiffusionthrough novel simplifications of the Mittag-Leffler function. For the case of time-fractional subdiffusion, we compute the kurtosis for the Mittag-Leffler function, which provides both a connection and physical context to the much-used approach of diffusional kurtosis imaging. We provide Monte Carlo simulations to illustrate the concepts of anomalous diffusion as stochastic processes of the random walk. Finally, we demonstrate the clinical utility of the Mittag-Leffler function as a model to describe tissue microstructure through estimations of subdiffusion and kurtosis with diffusion MRI measurements in the brain of a chronic ischemic stroke patient