38,407 research outputs found
Summary of Working Group I: Hadron Structure
A summary is given on the main aspects which were discussed by the working
group. They include new results on the deep inelastic scattering structure
functions and and their parametrizations, the
measurement of the gluon density, recent theoretical work on the small
behavior of structure functions, theoretical and experimental results on
, the direct photon cross section, and a discussion of the event
rates in the high range at Tevatron and the high range at HERA, as
well as possible interpretations.Comment: 22 pages latex, including 8 figures (ps,eps), to appear in the
Proceedings of the International Conference on Deep Inelastic Scattering,
Chicago, April 1997, AI
Non-axisymmetric oscillations of rapidly rotating relativistic stars by conformal flatness approximation
We present a new numerical code to compute non-axisymmetric eigenmodes of
rapidly rotating relativistic stars by adopting spatially conformally flat
approximation of general relativity. The approximation suppresses the radiative
degree of freedom of relativistic gravity and the field equations are cast into
a set of elliptic equations. The code is tested against the low-order f- and
p-modes of slowly rotating stars for which a good agreement is observed in
frequencies computed by our new code and those computed by the full theory.
Entire sequences of the low order counter-rotating f-modes are computed, which
are susceptible to an instability driven by gravitational radiation.Comment: 3 figures. To appear in Phys.Rev.
Rossby-Haurwitz waves of a slowly and differentially rotating fluid shell
Recent studies have raised doubts about the occurrence of r modes in
Newtonian stars with a large degree of differential rotation. To assess the
validity of this conjecture we have solved the eigenvalue problem for
Rossby-Haurwitz waves (the analogues of r waves on a thin-shell) in the
presence of differential rotation. The results obtained indicate that the
eigenvalue problem is never singular and that, at least for the case of a
thin-shell, the analogues of r modes can be found for arbitrarily large degrees
of differential rotation. This work clarifies the puzzling results obtained in
calculations of differentially rotating axi-symmetric Newtonian stars.Comment: 8pages, 3figures. Submitted to CQ
Recommended from our members
An education and negotiation of differences: the ‘schooling’ experiences of English-speaking Canadian children growing up with polio during the 1940s and 1950s
In this paper we present oral narratives focusing on schooling experiences of Canadians who lived with polio as children between 1940 and 1959. We argue that disabled students with polio received an education about the differences ascribed to them by individuals in authority (teachers, principals), by other young people, and through the dominant negative discourses of polio and normalizing, ableist practices of schooling. Using narrative accounts from participants’ interviews, we analyze their school experiences of difference: inaccessible physical and temporal spaces, bullying at school, exclusion from classes, and negotiating youth culture related to shoes, clothes and friendships. However, participants were not passive and they discussed how, along with families, they negotiated and occasionally defied normalizing processes. This research gives voice to a generation of disabled English-speaking Canadians, whose stories about school have not been heard before
Oscillations of vertically integrated relativistic tori -II. Axisymmetric modes in a Kerr spacetime
This is the second of a series of papers investigating the oscillation
properties of relativistic, non-selfgravitating tori orbiting around black
holes. Extending the work done in a Schwarzschild background, we here consider
the axisymmetric oscillations of vertically integrated tori in a Kerr
spacetime. The tori are modeled with a number of different non-Keplerian
distributions of specific angular momentum and we discuss how the oscillation
properties depend on these and on the rotation of the central black hole. We
first consider a local analysis to highlight the relations between acoustic and
epicyclic oscillations in a Kerr spacetime and subsequently perform a global
eigenmode analysis to compute the axisymmetric p modes. In analogy with what
found in a Schwarzschild background, these modes behave as sound waves that are
modified by rotation and are globally trapped in the torus. For constant
distributions of specific angular momentum, the eigenfrequencies appear in a
sequence 2:3:4:... which is essentially independent of the size of the disc and
of the black hole rotation. For non-constant distributions of angular momentum,
on the other hand, the sequence depends on the properties of the disc and on
the spin of the black hole, becoming harmonic for sufficiently large tori. We
also comment on how p modes could explain the high frequency quasi-periodic
oscillations observed in low-mass X-ray binaries with a black hole candidate
and the properties of an equivalent model in Newtonian physics.Comment: 13 pages, MNRAS, in pres
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