250 research outputs found
Radial excitations of Q-balls, and their D-term
We study the structure of the energy-momentum tensor of radial excitations of
Q-balls in scalar field theories with U(1) symmetry. The obtained numerical
results for the excitations allow us to study in detail
patterns how the solutions behave with N. We show that although the fields and
energy-momentum tensor densities exhibit a remarkable degree of complexity, the
properties of the solutions scale with N with great regularity. This is to best
of our knowledge the first study of the D-term d1 for excited states, and we
demonstrate that it is negative --- in agreement with results from literature
on the d1 of ground state particles.Comment: 11 pages, 12 figure
Chukchis
This chapter is about the 'Chukchis' the indigenous people of the far northeast of Russia. Historically engaged in reindeer herding and sea mammal hunting.
Published in the "Supplement to the Modern Encyclopedia of Russian, Soviet and Eurasian History" published by Academic International Pres
The Chukchis and Siberian Yupiks of the Russian Far East.
The Chukotka Autonomous Region of the Russian Federation is inhabited by several Native and non-Native peoples. The Chukchis and Siberian Yupiks constitute the two most numerous Native groups in the region, while ethnic Russians and Ukrainians dominate among the non-Native population. According to the last census of 1989, there were approx. 15,000 Chukchis and 1,700 Yupiks living within Russia. More than 90% of the Yupiks and most of the Chukchis live within the borders of the Chukotka Autonomous Okrug. Some Chukchis also live in the Sakha Republic to the west and in the Magadan Province to the south.
Historically, significant cultural differences developed between the coastal Chukchis and Yupiks in eastern Chukotka (on the Chukchi Peninsula, roughly coinciding with Providenskii and Chukotskii districts) and the tundra or reindeer Chukchi of western Chukotka. Thus, the similarities among coastal Chukchis and Yupiks were often more pronounced than among coastal and reindeer Chukchis. Commensurate with the ethnographic expertise of the authors, our account will focus on the Yupiks and Chukchis of the Chukchi Peninsula and the Chukchis of the Anadyr River Basin (Anadyrskii District)
The Chukchis and Siberian Yupiks of the Russian Far East.
The Chukotka Autonomous Region of the Russian Federation is inhabited by several Native and non-Native peoples. The Chukchis and Siberian Yupiks constitute the two most numerous Native groups in the region, while ethnic Russians and Ukrainians dominate among the non-Native population. According to the last census of 1989, there were approx. 15,000 Chukchis and 1,700 Yupiks living within Russia. More than 90% of the Yupiks and most of the Chukchis live within the borders of the Chukotka Autonomous Okrug. Some Chukchis also live in the Sakha Republic to the west and in the Magadan Province to the south.
Historically, significant cultural differences developed between the coastal Chukchis and Yupiks in eastern Chukotka (on the Chukchi Peninsula, roughly coinciding with Providenskii and Chukotskii districts) and the tundra or reindeer Chukchi of western Chukotka. Thus, the similarities among coastal Chukchis and Yupiks were often more pronounced than among coastal and reindeer Chukchis. Commensurate with the ethnographic expertise of the authors, our account will focus on the Yupiks and Chukchis of the Chukchi Peninsula and the Chukchis of the Anadyr River Basin (Anadyrskii District)
Parallel Implementation of the PHOENIX Generalized Stellar Atmosphere Program
We describe the parallel implementation of our generalized stellar atmosphere
and NLTE radiative transfer computer program PHOENIX. We discuss the parallel
algorithms we have developed for radiative transfer, spectral line opacity, and
NLTE opacity and rate calculations. Our implementation uses a MIMD design based
on a relatively small number of MPI library calls. We report the results of
test calculations on a number of different parallel computers and discuss the
results of scalability tests.Comment: To appear in ApJ, 1997, vol 483. LaTeX, 34 pages, 3 Figures, uses
AASTeX macros and styles natbib.sty, and psfig.st
Who owns Siberian ethnography? A critical assessment of a re-internationalized field.
Although Siberian ethnography was an open and international field at the turn of the 20th century, from about 1930 until the late 1980s Siberia was for the most part closed to foreigners and therefore to Western ethnographers. This allowed Soviet ethnographers to establish a virtual monopoly on Siberian field sites. Soviet and Western anthropology developed during that period in relative isolation from one another, allowing methodologies and theoretical approaches to diverge. During glasnost’ and after the collapse of the Soviet Union, the Siberian field was reopened and field studies were conducted by several Western ethnographers. The resulting encounter between Western and former Soviet ethnographers in the 1980s and 1990s produced a degree of cultural shock as well new challenges and opportunities on both sides. This is an experiential account of the mood of these newly reunited colleagues at the turn of the 21st century
Antisense sequencing improves the accuracy and precision of A-to-I editing measurements using the peak height ratio method
<p>Abstract</p> <p>Background</p> <p>A-to-I RNA editing is found in all phyla of animals and contributes to transcript diversity that may have profound impacts on behavior and physiology. Many transcripts of genes involved in axonal conductance, synaptic transmission and modulation are the targets of A-to-I RNA editing. There are a number of methods to measure the extent of A-to-I RNA editing, but they are generally costly and time consuming. One way to determine the frequency of A-to-I RNA editing is the peak height ratio method, which compares the size of peaks on electropherograms that represent unedited and edited sites.</p> <p>Findings</p> <p>Sequencing of 4 editing sites of the <it>Dα6 </it>nicotinic acetylcholine receptor subunit with an antisense primer (which uses T/C peaks to measure unedited and edited sites, respectively) showed very accurate and precise measurements of A-to-I RNA editing. The accuracy and precision were excellent for all editing sites, including those edited with high or low frequencies. The frequency of A-to-I RNA editing was comparable to the editing frequency as measured by clone counting from the same sample. Sequencing these same sites with the sense primer (which uses A/G peaks) yielded inaccurate and imprecise measurements.</p> <p>Conclusions</p> <p>We have validated and improved the accuracy and precision of the peak height ratio method to measure the frequency of A-to-I RNA editing, and shown that results are primer specific. Thus, the correct sequencing primer must be utilized for the most dependable data. When compared to other methods used to measure the frequency of A-to-I RNA editing, the major benefits of the peak height ratio are that this method is inexpensive, fast, non-labor intensive and easily adaptable to many laboratory and field settings.</p
Analysis of Keck HIRES spectra of early L-type dwarfs
We present analyses of high resolution and medium resolution spectra of early
L dwarfs. We used our latest set of model atmospheres to reproduce and analyze
the observed features. We can model the optical flux and the atomic line
profiles with the best accuracy to date. The models used to reproduce the
observations include dust condensation and dust opacities. Compared to previous
studies using older models we find that our dust treatment is much improved.
The derived parameters for the objects are well in the expected range for old
very low mass objects. This is also supported by the absence of Li in most of
the objects. For the objects showing Li we can be almost certain that those are
brown dwarfs. However, a spectral analysis in general, and this one in
particular can only very roughly determine mass and age.Comment: AASTeX5.0. 26 pages, including all figures, Accepted for Ap
Spectral Properties of Brown Dwarfs and Hot Jupiters
Brown dwarfs bridge the gap between the stellar and planetary mass regimes.
Evolving from conditions very similar to the lowest-mass stars, the atmospheres
of older brown dwarfs closely resemble those expected in close-in extrasolar
giant planets, and with cooler BDs still being discovered, more and more
approach the properties of gas giants at wider separation. Interpreting the
spectra of BDs is therefore a crucial step towards understanding and predicting
the spectral and thermal properties of EGPs.
Essential properties of substellar atmospheres are massive molecular
line-blanketing and the condensation of species with decreasing Teff, changing
the chemical equilibrium composition and causing absorption from dust grains.
More complex details involve the distribution of dust clouds over the surface
giving rise to temporal variability, and possible deviations from chemical
equilibrium conditions. In the case of close-in EGPs and some BDs in binary
systems, the effect of irradiation from the primary significantly affects the
spectral properties and thermal evolution.Comment: 12 pages, 6 figures, Review to be published in "High Resolution
Infrared Spectroscopy in Astronomy", Proceedings of the ESO Workshop Held in
Garching, Germany, 18-21 Nov., 2003, eds. H.U. Kaeufl, R. Siebenmorgen, & A.
Moorwood, ESO Astrophysics Symposia
http://www.eso.org/gen-fac/meetings/ekstasy2003
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