23,905 research outputs found
Oedipus of many pains: Strategies of contest in Homeric poetry
In this paper we analyse Oedipus’ appearance during Odysseus’ tale in book 11 of Homer’s Odyssey in order to outline and test a methodology for appreciating the poetic and thematic implications of moments when ‘extraneous’ narratives or traditions appear in the Homeric poems. Our analysis, which draws on oral-formulaic theory, is offered partly as a re-evaluation of standard scholarly approaches that tend to over-rely on the assumed pre-eminence of Homeric narratives over other traditions in their original contexts or approaches that reduce such moments to instances of allusions to or parallels with fixed texts. In conjunction with perspectives grounded in orality, we emphasise the agonistic character of Greek poetry to explore the ways in which Odysseus’ articulation of his Oedipus narrative exemplifies an attempt to appropriate and manipulate a rival tradition in the service of a particular narrative’s ends. We focus specifically on the resonance of the phrases algea polla and mega ergon used by Odysseus as a narrator to draw a web of interconnections throughout Homeric and Archaic Greek poetry. Such an approach, in turn, suggests to what extent the Homeric Oedipus passage speaks to the themes and concerns of Homeric poetry rather than some lost Oedipal epic tradition and illustrates the importance of recognizing the deeply competitive nature of Homeric narratives vis-à-vis other narrative traditions
Characterization of surficial units on Mars using Viking orbiter multispectral image and thermal data
Albedo and thermal property correlations of the topography of Mars were conducted with emphases upon the types and origins of materials exposed in the central equatorial region. This area displays a wide variation in color, albedo and thermal properties, and is relatively free of dust and haze. The physical, mineralogical and elemental characteristics of this area are discussed
Transitions in non-conserving models of Self-Organized Criticality
We investigate a random--neighbours version of the two dimensional
non-conserving earthquake model of Olami, Feder and Christensen [Phys. Rev.
Lett. {\bf 68}, 1244 (1992)]. We show both analytically and numerically that
criticality can be expected even in the presence of dissipation. As the
critical level of conservation, , is approached, the cut--off of the
avalanche size distribution scales as . The
transition from non-SOC to SOC behaviour is controlled by the average branching
ratio of an avalanche, which can thus be regarded as an order
parameter of the system. The relevance of the results are discussed in
connection to the nearest-neighbours OFC model (in particular we analyse the
relevance of synchronization in the latter).Comment: 8 pages in latex format; 5 figures available upon reques
Stellar Oscillations Network Group
Stellar Oscillations Network Group (SONG) is an initiative aimed at designing
and building a network of 1m-class telescopes dedicated to asteroseismology and
planet hunting. SONG will have 8 identical telescope nodes each equipped with a
high-resolution spectrograph and an iodine cell for obtaining precision radial
velocities and a CCD camera for guiding and imaging purposes. The main
asteroseismology targets for the network are the brightest (V<6) stars. In
order to improve performance and reduce maintenance costs the instrumentation
will only have very few modes of operation. In this contribution we describe
the motivations for establishing a network, the basic outline of SONG and the
expected performance.Comment: Proc. Vienna Workshop on the Future of Asteroseismology, 20 - 22
September 2006. Comm. in Asteroseismology, Vol. 150, in the pres
Hawking Radiation for Non-minimally Coupled Matter from Generalized 2D Black Hole Models
It is well known that spherically symmetric reduction of General Relativity
(SSG) leads to non-minimally coupled scalar matter. We generalize (and correct)
recent results to Hawking radiation for a class of dilaton models which share
with the Schwarzschild black hole non-minimal coupling of scalar fields and the
basic global structure. An inherent ambiguity of such models (if they differ
from SSG) is discussed. However, for SSG we obtain the rather disquieting
result of a negative Hawking flux at infinity, if the usual recipe for such
calculations is applied.Comment: 8 page
Phytoplankton Community and Algal Toxicity at a Recurring Bloom in Sullivan Bay, Kabetogama Lake, Minnesota, USA
Kabetogama Lake in Voyageurs National Park, Minnesota, USA suffers from recurring late summer algal blooms that often contain toxin-producing cyanobacteria. Previous research identified the toxin microcystin in blooms, but we wanted to better understand how the algal and cyanobacterial community changed throughout an open water season and how changes in community structure were related to toxin production. Therefore, we sampled one recurring bloom location throughout the entire open water season. The uniqueness of this study is the absence of urban and agricultural nutrient sources, the remote location, and the collection of samples before any visible blooms were present. Through quantitative polymerase chain reaction (qPCR), we discovered that toxin-forming cyanobacteria were present before visible blooms and toxins not previously detected in this region (anatoxin-a and saxitoxin) were present, indicating that sampling for additional toxins and sampling earlier in the season may be necessary to assess ecosystems and human health risk
Boundary effects in a random neighbor model of earthquakes
We introduce spatial inhomogeneities (boundaries) in a random neighbor
version of the Olami, Feder and Christensen model [Phys. Rev. Lett. 68, 1244
(1992)] and study the distributions of avalanches starting both from the bulk
and from the boundaries of the system. Because of their clear geophysical
interpretation, two different boundary conditions have been considered (named
free and open, respectively). In both cases the bulk distribution is described
by the exponent . Boundary distributions are instead
characterized by two different exponents and , for free and open boundary conditions, respectively. These
exponents indicate that the mean-field behavior of this model is correctly
described by a recently proposed inhomogeneous form of critical branching
process.Comment: 6 pages, 2 figures ; to appear on PR
Receiver Architectures for MIMO-OFDM Based on a Combined VMP-SP Algorithm
Iterative information processing, either based on heuristics or analytical
frameworks, has been shown to be a very powerful tool for the design of
efficient, yet feasible, wireless receiver architectures. Within this context,
algorithms performing message-passing on a probabilistic graph, such as the
sum-product (SP) and variational message passing (VMP) algorithms, have become
increasingly popular.
In this contribution, we apply a combined VMP-SP message-passing technique to
the design of receivers for MIMO-ODFM systems. The message-passing equations of
the combined scheme can be obtained from the equations of the stationary points
of a constrained region-based free energy approximation. When applied to a
MIMO-OFDM probabilistic model, we obtain a generic receiver architecture
performing iterative channel weight and noise precision estimation,
equalization and data decoding. We show that this generic scheme can be
particularized to a variety of different receiver structures, ranging from
high-performance iterative structures to low complexity receivers. This allows
for a flexible design of the signal processing specially tailored for the
requirements of each specific application. The numerical assessment of our
solutions, based on Monte Carlo simulations, corroborates the high performance
of the proposed algorithms and their superiority to heuristic approaches
High-precision abundances of elements in Kepler LEGACY stars. Verification of trends with stellar age
HARPS-N spectra with S/N > 250 and MARCS model atmospheres were used to
derive abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, and Y in ten
stars from the Kepler LEGACY sample (including the binary pair 16 Cyg A and B)
selected to have metallicities in the range -0.15 < [Fe/H] < +0.15 and ages
between 1 and 7 Gyr. Stellar gravities were obtained from seismic data and
effective temperatures were determined by comparing non-LTE iron abundances
derived from FeI and FeII lines. Available non-LTE corrections were also
applied when deriving abundances of the other elements. The results support the
[X/Fe]-age relations previously found for solar twins. [Mg/Fe], [Al/Fe], and
[Zn/Fe] decrease by ~0.1 dex over the lifetime of the Galactic thin disk due to
delayed contribution of iron from Type Ia supernovae relative to prompt
production of Mg, Al, and Zn in Type II supernovae. [Y/Mg] and [Y/Al], on the
other hand, increase by ~0.3 dex, which can be explained by an increasing
contribution of s-process elements from low-mass AGB stars as time goes on. The
trends of [C/Fe] and [O/Fe] are more complicated due to variations of the ratio
between refractory and volatile elements among stars of similar age. Two stars
with about the same age as the Sun show very different trends of [X/H] as a
function of elemental condensation temperature Tc and for 16 Cyg, the two
components have an abundance difference, which increases with Tc. These
anomalies may be connected to planet-star interactions.Comment: 13 pages with 7 figures. Accepted for publication in A&
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