10,175 research outputs found
An essay on character portrayal, style, and technique of writing in Maxwell Anderson\u27s biographical plays in verse
The purpose of this chapter is to acquaint the reader with the general scope and trend of Maxwell Anderson\u27s work in order to give a more complete conspectus for the discussion of his plays. By so doing a foundation will be laid for a more intelligible discussion of the specific aspects of the seven plays concerned in the thesis proper, the title of which is, An Essay on Character Portrayal, Style, and Technique of\u27 Writing in Maxwell Anderson\u27s Biographical Plays in Verse
A Cosmic Microwave Background feature consistent with a cosmic texture
The Cosmic Microwave Background provides our most ancient image of the
Universe and our best tool for studying its early evolution. Theories of high
energy physics predict the formation of various types of topological defects in
the very early universe, including cosmic texture which would generate hot and
cold spots in the Cosmic Microwave Background. We show through a Bayesian
statistical analysis that the most prominent, 5 degree radius cold spot
observed in all-sky images, which is otherwise hard to explain, is compatible
with having being caused by a texture. From this model, we constrain the
fundamental symmetry breaking energy scale to be phi_0 ~ 8.7 x 10^(15) GeV. If
confirmed, this detection of a cosmic defect will probe physics at energies
exceeding any conceivable terrestrial experiment.Comment: Accepted by Science. Published electronically via Science Express on
25 October 2007, http://www.sciencemag.org/cgi/content/abstract/114869
Computational science and re-discovery: open-source implementations of ellipsoidal harmonics for problems in potential theory
We present two open-source (BSD) implementations of ellipsoidal harmonic
expansions for solving problems of potential theory using separation of
variables. Ellipsoidal harmonics are used surprisingly infrequently,
considering their substantial value for problems ranging in scale from
molecules to the entire solar system. In this article, we suggest two possible
reasons for the paucity relative to spherical harmonics. The first is
essentially historical---ellipsoidal harmonics developed during the late 19th
century and early 20th, when it was found that only the lowest-order harmonics
are expressible in closed form. Each higher-order term requires the solution of
an eigenvalue problem, and tedious manual computation seems to have discouraged
applications and theoretical studies. The second explanation is practical: even
with modern computers and accurate eigenvalue algorithms, expansions in
ellipsoidal harmonics are significantly more challenging to compute than those
in Cartesian or spherical coordinates. The present implementations reduce the
"barrier to entry" by providing an easy and free way for the community to begin
using ellipsoidal harmonics in actual research. We demonstrate our
implementation using the specific and physiologically crucial problem of how
charged proteins interact with their environment, and ask: what other
analytical tools await re-discovery in an era of inexpensive computation?Comment: 25 pages, 3 figure
Sommerfeld's image method in the calculation of van der Waals forces
We show how the image method can be used together with a recent method
developed by C. Eberlein and R. Zietal to obtain the dispersive van der Waals
interaction between an atom and a perfectly conducting surface of arbitrary
shape. We discuss in detail the case of an atom and a semi- infinite conducting
plane. In order to employ the above procedure to this problem it is necessary
to use the ingenious image method introduced by Sommerfeld more than one
century ago, which is a generalization of the standard procedure. Finally, we
briefly discuss other interesting situations that can also be treated by the
joint use of Sommerfeld's image technique and Eberlein-Zietal method.Comment: To appear in the proceedings of Conference on Quantum Field Theory
under the Influence of External Conditions (QFEXT11
Detection of the ISW effect and corresponding dark energy constraints made with directional spherical wavelets
Using a directional spherical wavelet analysis we detect the integrated
Sachs-Wolfe (ISW) effect, indicated by a positive correlation between the
first-year Wilkinson Microwave Anisotropy Probe (WMAP) and NRAO VLA Sky Survey
(NVSS) data. Detections are made using both a directional extension of the
spherical Mexican hat wavelet and the spherical butterfly wavelet. We examine
the possibility of foreground contamination and systematics in the WMAP data
and conclude that these factors are not responsible for the signal that we
detect. The wavelet analysis inherently enables us to localise on the sky those
regions that contribute most strongly to the correlation. On removing these
localised regions the correlation that we detect is reduced in significance, as
expected, but it is not eliminated, suggesting that these regions are not the
sole source of correlation between the data. This finding is consistent with
predictions made using the ISW effect, where one would expect weak correlations
over the entire sky. In a flat universe the detection of the ISW effect
provides direct and independent evidence for dark energy. We use our detection
to constrain dark energy parameters by deriving a theoretical prediction for
the directional wavelet covariance statistic for a given cosmological model.
Comparing these predictions with the data we place constraints on the
equation-of-state parameter and the vacuum energy density .
We also consider the case of a pure cosmological constant, i.e. . For
this case we rule out a zero cosmological constant at greater than the 99.9%
significance level. All parameter estimates that we obtain are consistent with
the standand cosmological concordance model values.Comment: 16 pages, 13 figures; replaced to match version accepted by MNRA
Observations of Foraging Northern Fulmars (Fulmarus Glacialis) in the Canadian High Arctic
We summarize observations of foraging northern fulmars (Fulmarus glacialis) in the Barrow Strait-Lancaster Sound region of the Northwest Territories from June to September 1984-90 and in Admiralty Inlet, N.W.T., in July 1989. In each year, fulmars scavenged hunter-killed marine mammal remains in the vicinity of Resolute Bay. Large feeding flocks, aggregated primarily along tide lines and at upwelling sites, exploited primarily calanoid copepods by surface seizing and diving. Late-season onshore movement of Arctic cod (Boreogadus saida) resulted in flocks of several thousand fulmars capturing cod by surface and pursuit diving. We determined experimentally that northern fulmars are capable of diving to 3 m to retrieve cod.Key words: northern fulmar, Fulrmarus glacialis, feeding behaviour, diving, Barrow Strait, Lancaster SoundRÉSUMÉ. On résume les observations faites sur des fulmars boréaux (Fulmarus glacialis) en train de se ravitailler dans la région du détroit de Barrow et du détroit de Lancaster dans les Territoires du Nord-Ouest, de juin à septembre 1984 à 1990, et dans l'inlet de l'Amirauté (T.N.-O.) en juillet1989. Chaque année, les fulmars se repaissaient des restes de mammifères marins tués par des chasseurs à proximité de la baie Resolute. De grandes volées s'attroupaient pour se nourrir, surtout le long des laisses de marée et aux sites d'émergence, et pêchaient principalement des calanus,en les saisissant à la surface et en plongée. La migration de fin de saison de la morue polaire (Boreogadus saida) vers le rivage attirait des volées composées de plusieurs milliers de fulmars qui capturaient la morue en piquant à la surface et en la poursuivant sous l'eau. On a déterminé expérimentalement que le fulmar boréal est capable de plonger à 3 m sous la surface pour retrouver la morue.Mots clés: fulmar boréal, Fulrnarus glacialis, comportement alimentaire, plongée, détroit de Barrow, détroit de Lancaste
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