1,360 research outputs found
In the border's shadow: Reimagining urban spaces in Strasbourg, 1918-39
Copyright @ The Author(s) 2013. This is the author's final version of the article. The final publication is available from the link below.This article explores controversies over festivities and monument construction in interwar Strasbourg. After the return of Alsace to France in 1918, these battles became emblematic of broader debates about the region’s place in France and relationship with Germany, as different groups and individuals in Paris and Strasbourg used them to promote their views of the reintegration of Alsace into France. In these debates, the dominant understanding of Strasbourg treated the city as the limits of French territory, and a frontier with Germany. But this idea was challenged by ideas of the city as the heart of a transnational, cross border community, or a regional capital. These ideas co-existed, but were contested and were not articulated simultaneously. Through a discussion of the use of these ideas in debates over urban spaces in Strasbourg, this article traces how attitudes towards borders change over time, and vary according to the political context.British Academ
Tolkien\u27s Allusive Backstory: Immortality and Belief in the Fantasy Frame
Mortality and immortality underlie the “emotional truth” (95) of Tolkien’s backstory, a truth which draws us as readers into a world in which longing and loss, death and deathlessness, are the foundation of a sub-created world that we as readers desire. The fantasy frame in Tolkien’s legendarium is extremely deep, and has been highly influential on other creators
Links between different analytic descriptions of constant mean curvature surfaces
Transformations between different analytic descriptions of constant mean
curvature (CMC) surfaces are established. In particular, it is demonstrated
that the system descriptive of CMC surfaces within the
framework of the generalized Weierstrass representation, decouples into a
direct sum of the elliptic Sh-Gordon and Laplace equations. Connections of this
system with the sigma model equations are established. It is pointed out, that
the instanton solutions correspond to different Weierstrass parametrizations of
the standard sphere
Zeldovich flow on cosmic vacuum background: new exact nonlinear analytical solution
A new exact nonlinear Newtonian solution for a plane matter flow superimposed
on the isotropic Hubble expansion is reported. The dynamical effect of cosmic
vacuum is taken into account. The solution describes the evolution of nonlinear
perturbations via gravitational instability of matter and the termination of
the perturbation growth by anti-gravity of vacuum at the epoch of transition
from matter domination to vacuum domination. On this basis, an `approximate' 3D
solution is suggested as an analog of the Zeldovich ansatz.Comment: 9 pages, 1 figure
Could the Pioneer anomaly have a gravitational origin?
If the Pioneer anomaly has a gravitational origin, it would, according to the
equivalence principle, distort the motions of the planets in the Solar System.
Since no anomalous motion of the planets has been detected, it is generally
believed that the Pioneer anomaly can not originate from a gravitational source
in the Solar System. However, this conclusion becomes less obvious when
considering models that either imply modifications to gravity at long range or
gravitational sources localized to the outer Solar System, given the
uncertainty in the orbital parameters of the outer planets. Following the
general assumption that the Pioneer spacecraft move geodesically in a
spherically symmetric spacetime metric, we derive the metric disturbance that
is needed in order to account for the Pioneer anomaly. We then analyze the
residual effects on the astronomical observables of the three outer planets
that would arise from this metric disturbance, given an arbitrary metric theory
of gravity. Providing a method for comparing the computed residuals with actual
residuals, our results imply that the presence of a perturbation to the
gravitational field necessary to induce the Pioneer anomaly is in conflict with
available data for the planets Uranus and Pluto, but not for Neptune. We
therefore conclude that the motion of the Pioneer spacecraft must be
non-geodesic. Since our results are model independent within the class of
metric theories of gravity, they can be applied to rule out any model of the
Pioneer anomaly that implies that the Pioneer spacecraft move geodesically in a
perturbed spacetime metric, regardless of the origin of this metric
disturbance.Comment: 16 pages, 6 figures. Rev. 3: Major revision. Accepted for publication
in Phys. Rev. D. Rev. 4: Added two reference
Determining the correct intervention based on intial fluency: A comparison of explicit timing and cover, copy, compare.
There has been an increase of students falling below proficient on mathematics assessments. This increases the demand for high quality interventions to address these issues. Previous research by Codding et al. (2007), has suggested that intervention selection could be made based upon a student's pattern of responding. The current study attempted to replicate that study and validate those findings. The instructional hierarchy model was used to inform the progression of student's skill mastery. It was assumed that all students had already achieved the first step in the instructional hierarchy and the focus was placed upon the second step, fluency. Students were randomly assigned to one of two treatment conditions: Cover, Copy and Compare or Explicit Timing. The findings of the current study did not provide sufficient evidence to support the claim made by Codding et al. (2007)
Self Interacting Dark Matter in the Solar System
Weakly coupled, almost massless, spin 0 particles have been predicted by many
extensions of the standard model of particle physics. Recently, the PVLAS group
observed a rotation of polarization of electromagnetic waves in vacuum in the
presence of transverse magnetic field. This phenomenon is best explained by the
existence of a weakly coupled light pseudoscalar particle. However, the
coupling required by this experiment is much larger than the conventional
astrophysical limits. Here we consider a hypothetical self-interacting
pseudoscalar particle which couples weakly with visible matter.
Assuming that these pseudoscalars pervade the galaxy, we show that the solar
limits on the pseudoscalar-photon coupling can be evaded.Comment: 17 pages, 2 figure
Phemeranthus rugospermus (Holz.) Kiger
https://thekeep.eiu.edu/herbarium_specimens_byname/20844/thumbnail.jp
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