1,262 research outputs found
Alienating Aliens: Equal Protection Violations in the Structures of State Public-Benefit Schemes
Rockets: Physical science teacher's guide with activities
This guide begins with background information sections on the history of rocketry, scientific principles, and practical rocketry. The sections on scientific principles and practical rocketry are based on Isaac Newton's three laws of motion. These laws explain why rockets work and how to make them more efficient. The background sections are followed with a series of physical science activities that demonstrate the basic science of rocketry. Each activity is designed to be simple and take advantage of inexpensive materials. Construction diagrams, materials and tools lists, and instructions are included. A brief discussion elaborates on the concepts covered in the activities and is followed with teaching notes and discussion questions. The guide concludes with a glossary of terms, suggested reading list, NASA educational resources, and an evaluation questionnaire with a mailer
A PREVIOUSLY VALIDATED PERIPHERAL BLOOD GENE EXPRESSION SCORE IS PRIMARILY INFLUENCED BY PLAQUE BURDEN, RATHER THAN ISCHEMIA, IN 371 PATIENTS FROM THE COMPASS MULTI-CENTER STUDY
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An Empirical Study of Dynamic Scheduling on Rings of Processors
The authors empirically analyze and compare two distributed low-overhead policies for scheduling dynamic tree-structured computations on rings of identical PEs. The experiments show that both policies give significant parallel speedup on large classes of computations, and that one yields almost optimal speedup on moderate size rings. They believe that the methodology of experiment design and analysis will prove useful in other such studies
Microgravity: Teacher's guide with activities for physical science
This guide is an educational tool for teachers of grades 5 through 12. It is an introduction to microgravity and its application to spaceborne laboratory experiments. Specific payloads and missions are mentioned with limited detail, including Spacelab, the International Microgravity Laboratory, and the United States Microgravity Laboratory. Activities for students demonstrate chemistry, mathematics, and physics applications of microgravity. Activity objectives include: modeling how satellites orbit Earth; demonstrating that free fall eliminates the local effects of gravity; measuring the acceleration environments created by different motions; using a plasma sheet to observe acceleration forces that are experienced on board a space vehicle; demonstrating how mass can be measured in microgravity; feeling how inertia affects acceleration; observing the gravity-driven fluid flow that is caused by differences in solution density; studying surface tension and the fluid flows caused by differences in surface tension; illustrating the effects of gravity on the burning rate of candles; observing candle flame properties in free fall; measuring the contact angle of a fluid; illustrating the effects of gravity and surface tension on fiber pulling; observing crystal growth phenomena in a 1-g environment; investigating temperature effects on crystal growth; and observing crystal nucleation and growth rate during directional solidification. Each activity includes a background section, procedure, and follow-up questions
Modeling of gyrosynchrotron radio emission pulsations produced by MHD loop oscillations in solar flares
A quantitative study of the observable radio signatures of the sausage, kink,
and torsional MHD oscillation modes in flaring coronal loops is performed.
Considering first non-zero order effect of these various MHD oscillation modes
on the radio source parameters such as magnetic field, line of sight, plasma
density and temperature, electron distribution function, and the source
dimensions, we compute time dependent radio emission (spectra and light
curves). The radio light curves (of both flux density and degree of
polarization) at all considered radio frequencies are than quantified in both
time domain (via computation of the full modulation amplitude as a function of
frequency) and in Fourier domain (oscillation spectra, phases, and partial
modulation amplitude) to form the signatures specific to a particular
oscillation mode and/or source parameter regime. We found that the parameter
regime and the involved MHD mode can indeed be distinguished using the
quantitative measures derived in the modeling. We apply the developed approach
to analyze radio burst recorded by Owens Valley Solar Array and report possible
detection of the sausage mode oscillation in one (partly occulted) flare and
kink or torsional oscillations in another flare.Comment: ApJ, accepte
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