217,844 research outputs found
Spin effects in hard exclusive electroproduction of mesons
In this talk various spin effects in hard exclusive electroproduction of
mesons are briefly reviewed. The data are discussed in the light of recent
theoretical calculations within the frame work of the handbag approach.Comment: 11 pages, 12 figures, using Latex, talk presented at the conference
in honor of Prof. A. Efremov's 75th birthday held at Trento, July, 200
Gravity-modes in ZZ Ceti Stars. II. Effects of Turbulent Dissipation
We investigate dynamical interactions between turbulent convection and g-mode
pulsations in ZZ Ceti variables (DAVs). Since our understanding of turbulence
is rudimentary, we are compelled to settle for order of magnitude results. A
key feature of these interactions is that convective response times are much
shorter than pulsation periods. Thus the dynamical interactions enforce near
uniform horizontal velocity inside the convection zone. They also give rise to
a narrow shear layer in the region of convective overshoot at the top of the
radiative interior. Turbulent damping inside the convection zone is negligible
for all modes, but that in the region of convective overshoot may be
significant for a few long period modes near the red edge of the instability
strip. These conclusions are in accord with those reached earlier by Brickhill.
Our major new result concerns nonlinear damping arising from the
Kelvin-Helmholtz instability of the aforementioned shear layer. Amplitudes of
overstable modes saturate where dissipation due to this instability balances
excitation by convective driving. This mechanism of amplitude saturation is
most effective for long period modes, and it may play an important role in
defining the red edge of the instability strip.Comment: 7 pages, including 2 figures. Used emulateapj.sty and apjfonts.sty
obtained from http://hea-www.harvard.edu/~alexey/emulateapj
On the boundaries between good and evil: Constructing multiple moralities in China
This essay discusses three contrasting versions of the relationship between good and evil in contemporary China: a spirit medium who maneuvers between them, a charismatic Christian group that forges an identity by defending the border between them, and an official state and religious discourse of banal goodness and universal love that that seeks to annihilate evil. Each defines good and evil differently, but more importantly, each imagines the nature of the boundary itself differently – as permeable and negotiable, clear and defensible, or simply intolerable. These varied conceptions help to shape alternate views of empathy, pluralism, and the problem of how to live with otherness
The Cauchy problem for the Pavlov equation
Commutation of multidimensional vector fields leads to integrable nonlinear
dispersionless PDEs arising in various problems of mathematical physics and
intensively studied in the recent literature. This report is aiming to solve
the scattering and inverse scattering problem for integrable dispersionless
PDEs, recently introduced just at a formal level, concentrating on the
prototypical example of the Pavlov equation, and to justify an existence
theorem for global bounded solutions of the associated Cauchy problem with
small data.Comment: In the new version the analytical technique was essentially revised.
The previous version contained a wrong statement about the solvability of the
inverse problem for large data. This problem remains ope
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