24,496 research outputs found
A New Day for Youth: Creating Sustainable Quality in Out-of-School Time
Reviews research on best practices and examines the elements needed to create and sustain high-quality afterschool and summer programs. Recommends a framework for improving staff capacity and training, support structures and leadership, and activities
Interrelation between radio and X-ray signatures of drifting subpulses in pulsars
We examined a model of partially screened gap region above the polar cap, in
which the electron-positron plasma generated by sparking discharges coexists
with thermionic flow ejected by the bombardment of the surface beneath these
sparks. Our special interest was the polar cap heating rate and the subpulse
drifting rate, both phenomena presumably associated with sparks operating at
the polar cap. We investigated correlation between the intrinsic drift rate and
polar cap heating rate and found that they are coupled to each other in such a
way that the thermal X-ray luminosity from heated polar cap depends only
on the observational tertiary subpulse drift periodicity (polar cap
carousel time). Within our model of partially screened gap we derived the
simple formula relating and , and showed that it holds for
PSRs B094310 and B1133+16, which are the only two pulsars in which both
and are presently known.Comment: 4 page
The Parallelometer: a mechanical device to study curvature
A simple mechanical device is introduced, the parallelometer, that can be
used to measure curvatures of surfaces. The device can be used as a practical
illustration of parallel transport of a vector and to study Berry phase shift
when it is carried along a loop on the surface. Its connection to the Foucault
pendulum is discussed. The experimental results can be successfully compared
with the theoretical expectations. The experiment is inexpensive and
conceptually easy to perform and understand for a beginner
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