985 research outputs found
On the detection of point sources in Planck LFI 70 GHz CMB maps based on cleaned K-map
We use the Planck LFI 70GHz data to further probe point source detection
technique in the sky maps of the cosmic microwave background (CMB) radiation.
The method developed by Tegmark et al. for foreground reduced maps and the
Kolmogorov parameter as the descriptor are adopted for the analysis of Planck
satellite CMB temperature data. Most of the detected points coincide with point
sources already revealed by other methods. However, we have also found 9 source
candidates for which still no counterparts are known.Comment: 11 pages, 3 figures, Accepted for publication in Modern Physics
Letters A. arXiv admin note: substantial text overlap with arXiv:1206.712
Almost Euclidean sections of the N-dimensional cross-polytope using O(N) random bits
It is well known that R^N has subspaces of dimension proportional to N on
which the \ell_1 norm is equivalent to the \ell_2 norm; however, no explicit
constructions are known. Extending earlier work by Artstein--Avidan and Milman,
we prove that such a subspace can be generated using O(N) random bits.Comment: 16 pages; minor changes in the introduction to make it more
accessible to both Math and CS reader
Boundary Energies and the Geometry of Phase Separation in Double--Exchange Magnets
We calculate the energy of a boundary between ferro- and antiferromagnetic
regions in a phase separated double-exchange magnet in two and three
dimensions. The orientation dependence of this energy can significantly affect
the geometry of the phase-separated state in two dimensions, changing the
droplet shape and possibly stabilizing a striped arrangement within a certain
range of the model parameters. A similar effect, albeit weaker, is also present
in three dimensions. As a result, a phase-separated system near the percolation
threshold is expected to possess intrinsic hysteretic transport properties,
relevant in the context of recent experimental findings.Comment: 6 pages, including 4 figures; expanded versio
Pilot Test of a Quality Rating and Improvement System in Early Education Programs in Magadan, Russian Federation and in Minnesota, United States of America
This study examined two questions: (1) What quality rating and improvement System (QRIS) will be useful for improving early childhood education programs in Magadan Region, RU and in Minnesota, USA? and (2) What is the agreement among raters in the US and in Russia, using scores on a QRIS for early childhood education programs in Magadan Region, RU and in Minnesota, USA? The study included translation of the Global Guidelines Assessment (GGA) (ACEI, 2008) into Russian. One quality review was completed for one early education program in each country. Completed reviews by eleven reviewers were delivered to Minnesota State University, Mankato for data entry and analysis. The report includes: (1) descriptive data for reviewers and for early education programs and (2) inter-rater agreement (consistency among assessors). This study concluded that there was excellent inter-rater agreement among reviewers in Russia and in the US. As a result of this investigation, this study concluded that the Global Guidelines Assessment will be useful for comparing early childhood education programs in Magadan, Russian Federation and in Minnesota, USA because the GGA is easy, affordable, and reliable to use for quality improvement of early education throughout the world. Now the GGA may be used in Russia as well
Social network analysis of manga: similarities to real-world social networks and trends over decades
Manga, Japanese comics, has been popular on a global scale. Social networks
among characters, which are often called character networks, may be a
significant contributor to their popularity. We collected data from 162 popular
manga that span over 70 years and analyzed their character networks. First, we
found that many of static and temporal properties of the character networks are
similar to those of real human social networks. Second, the character networks
of most manga are protagonist-centered such that a single protagonist interacts
with the majority of other characters. Third, the character networks for manga
mainly targeting boys have shifted to denser and less protagonist-centered
networks and with fewer characters over decades. Manga mainly targeting girls
showed the opposite trend except for the downward trend in the number of
characters. The present study, which relies on manga data sampled on an
unprecedented scale, paves the way for further population studies of character
networks and other aspects of comics.Comment: 17 pages, 9 figures, 1 tabl
On the absence of conduction electrons in the antiferromagnetic part of the phase-separated states in magnetic semiconductors
We have calculated the energies of the phase-separated states for degenerate
antiferromagnetic semiconductors including the possibility of the existence of
conduction electrons in the antiferromagnetic part of the phase-separated
states. It is demonstrated that, at T=0, the minimum energy corresponds to a
droplet phase with absence of electrons in the antiferromagnetic part.Comment: 13 pages, 4 figure
To the center of cold spot with Planck
The structure of the cold spot, of a non-Gaussian anomaly in the cosmic
microwave background (CMB) sky first detected by Vielva et al. is studied using
the data by Planck satellite. The obtained map of the degree of stochasticity
(K-map) of CMB for the cold spot, reveals, most clearly in 100 GHz band, a
shell-type structure with a center coinciding with the minima of the
temperature distribution. The shell structure is non-Gaussian at a 4\sigma
confidence level. Such behavior of the K-map supports the void nature of the
cold spot. The applied method can be used for tracing voids that have no
signatures in redshift surveys.Comment: A & A (in press), 4 pages, 5 figures; to match the published versio
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