The evolution of electron density and temperature distributions in the topside ionosphere during magnetic storms

The latitudinal distributions of electron density and temperature during geomagnetic storms in the mid-latitude topside ionosphere are observed to change in a manner than can be related to the evolution of ring current particle populations. The region of auroral precipitation is characterized by correlated increases in electron temperature and density. Equatorwards of this region, there is a broad belt of elevated electron temperatures and depressed electron densities which is usually much broader than any stable auroral red arc distinguishable from the ground, but which is nevertheless the same basic physical phenomenon. The changes of position of this belt can be related to prior bursts of geomagnetic activity and injection of ring current particles into the magnetosphere

Investigation of the effects of a moving acoustic medium on jet noise measurements

Noise from an unheated sonic jet in the presence of an external flow is measured in a free-jet wind tunnel using microphones located both inside and outside the flow. Comparison of the data is made with results of similar studies. The results are also compared with theoretical predictions of the source strength for jet noise in the presence of flow and of the effects of sound propagation through a shear layer

Magnetohydrodynamic Waves

The aim of this paper is to study some special magnetohydrodynamic waves and their connection with the methods of their production, that is, the boundary conditions. Possible wave motions of a fluid form the underlying structure of the mathematical description; hence a knowledge of their behavior leads to a deeper understanding of fluid dynamical problems. Furthermore there is some evidence that these waves can be produced in the laboratory and may occur in nature. These waves occur in a model fluid which is an ordinary gas dynamic fluid endowed with a scalar electrical conductivity σ. In practice there is a fairly direct application to slightly ionized gases and to conducting liquids. However the general method of approach also applies to fully ionized plasmas described by continuum equations

Factorization in hard diffraction

In this talk, I reviewed the role of factorization in diffraction hard scattering.Comment: Talk presented at the Ringberg Workshop on ``New Trends in HERA Physics 2001''. 10 pages, 6 postscript figures. Misprints correcte

The study of parameter optimization in vehicle-borne tracking systems Final technical report

Data smoothing technique for parameter optimization in free flight orbit vehicle-borne tracking system

Theory of Magnetodynamics Induced by Spin Torque in Perpendicularly Magnetized Thin Films

A nonlinear model of spin wave excitation using a point contact in a thin ferromagnetic film is introduced. Large-amplitude magnetic solitary waves are computed, which help explain recent spin-torque experiments. Numerical simulations of the fully nonlinear model predict excitation frequencies in excess of 0.2 THz for contact diameters smaller than 6 nm. Simulations also predict a saturation and red shift of the frequency at currents large enough to invert the magnetization under the point contact. The theory is approximated by a cubic complex Ginzburg-Landau type equation. The mode's nonlinear frequency shift is found by use of perturbation techniques, whose results agree with those of direct numerical simulations.Comment: 5 pages, 4 figures, submitted to PR

Observations of Mariner IV with the Parkes 210-ft Radio Telescope

Radio telescope test results from Mariner IV OBSERVATION

Assessing the Early Impact of School of One: Evidence from Three School-Wide Pilots

For more than 150 years, education has been organized around classrooms in which one teacher attempts to meet the needs of a large group of students who have a wide range of prior experiences, knowledge, and ways of learning. This structure makes it exceedingly difficult to ensure that all students meet the same standards of performance. School of One (SO1) is an innovative, technology-enhanced math program that seeks to "meet students where they are," by creating individual learning plans, offering multiple teaching strategies, and using daily assessments to monitor progress and adapt lessons as needed. This report evaluates SO1's impact on students' state test scores during the first year of school-wide implementation in three New York City middle schools. It also presents exploratory analysis examining whether exposure to more SO1 material, or mastery of SO1 skills, is associated with improved math performance. Given the early stage of the program's development, the authors caution that the evaluation should not be interpreted as a definitive assessment of SO1's effectiveness. Rather, the findings provide a preliminary assessment of SO1's initial impact on students' math achievement and offer insights that may contribute to the program's development and inform future research