160 research outputs found
Electron heating and acceleration for the nonlinear kinetic equation
Time evolution of the isotropic electron distribution function while heating for the nonlinear kinetic equation with the Landau-Fokker-Planck collisional integral is studied. The considered heating sources are mono kinetic distribution, hot ions, and a quasi-linear diffusion operator. The investigation is mainly concentrated on the formation of the distribution function and tail acceleration. The time-dependent solutions allowing the solutions in self-similar variables are examined. Also presented are analytical asymptotic solutions and comparison them with numerical results
Optical morphology of distant RATAN-600 radio galaxies from subarcsecond resolution NOT images
We present direct imaging data of 22 ultra steep spectrum radio sources
obtained at (or near) a subarcsecond seeing. The basic sample of 40 double
radio sources was selected from the RATAN-600 catalogue. The FRII-structure has
been confirmed with VLA and preliminary optical identifications which come from
the 6 m-telescope. As the RATAN-600 flux limit at 3.9 GHz ( 10mJy) is
fainter than that of major surveys, the sample may have high- contents. This
is also suggested by the faint magnitudes in the Hubble diagram. The final aim
is to create a homogeneous sample of high- radio galaxies in a well defined
strip around the sky, with faint radio limit and subarcsecond morphology down
to .
We could confirm 16 identifications down to 24. Most of the
extended objects have multicomponent structures as expected from other surveys
of high-redshift radio galaxies. We found five unresolved objects even with a
subarcsecond seeing. Of the remaining six objects, three are extremely faint
and the other three have such a complex environment that further observations
are needed to confirm the optical identification.Comment: A&AS in pres
Experimental Limit on the Cosmic Diffuse Ultra-high Energy Neutrino Flux
We report results from 120 hours of livetime with the Goldstone Lunar
Ultra-high energy neutrino Experiment (GLUE). The experiment searches for <10
ns microwave pulses from the lunar regolith, appearing in coincidence at two
large radio telescopes separated by 22 km and linked by optical fiber. Such
pulses would arise from subsurface electromagnetic cascades induced by
interactions of >= 100 EeV neutrinos in the lunar regolith. No candidates are
yet seen, and the implied limits constrain several current models for
ultra-high energy neutrino fluxes.Comment: 4 pages, 4 figures, revtex4 style. New intro section, Fig. 2, Fig 4;
in final PRL revie
MAIN MEASURES TO PREVENT «ATYPICAL PNEUMONIA» IMPORTATION AND DISSEMINATION AT IRKUTSKAYA PROVINCE TERRITORY
Organizing, preventive and anti-epidemic measures performed at the territory of Irkutskaya Province at the period of acute severe respiratory syndrome outbreak in the world are analyzed. The current experience will be used for improvement of the epidemiological surveillance to polish tactics of the preventive and anti-epidemic measures in case of a suspected «atypical pneumonia» patient detection
Dust-particle transport in tokamak edge plasmas
Dust particulates in the size range of 10nm-100{micro}m are found in all fusion devices. Such dust can be generated during tokamak operation due to strong plasma/material-surface interactions. Some recent experiments and theoretical estimates indicate that dust particles can provide an important source of impurities in the tokamak plasma. Moreover, dust can be a serious threat to the safety of next-step fusion devices. In this paper, recent experimental observations on dust in fusion devices are reviewed. A physical model for dust transport simulation, and a newly developed code DUSTT, are discussed. The DUSTT code incorporates both dust dynamics due to comprehensive dust-plasma interactions as well as the effects of dust heating, charging, and evaporation. The code tracks test dust particles in realistic plasma backgrounds as provided by edge-plasma transport codes. Results are presented for dust transport in current and next-step tokamaks. The effect of dust on divertor plasma profiles and core plasma contamination is examined
NCBI GEO: archive for high-throughput functional genomic data
The Gene Expression Omnibus (GEO) at the National Center for Biotechnology Information (NCBI) is the largest public repository for high-throughput gene expression data. Additionally, GEO hosts other categories of high-throughput functional genomic data, including those that examine genome copy number variations, chromatin structure, methylation status and transcription factor binding. These data are generated by the research community using high-throughput technologies like microarrays and, more recently, next-generation sequencing. The database has a flexible infrastructure that can capture fully annotated raw and processed data, enabling compliance with major community-derived scientific reporting standards such as ‘Minimum Information About a Microarray Experiment’ (MIAME). In addition to serving as a centralized data storage hub, GEO offers many tools and features that allow users to effectively explore, analyze and download expression data from both gene-centric and experiment-centric perspectives. This article summarizes the GEO repository structure, content and operating procedures, as well as recently introduced data mining features. GEO is freely accessible at http://www.ncbi.nlm.nih.gov/geo/
RC J0311+0507: A Candidate for Superpowerful Radio Galaxies in the Early Universe at Redshift z=4.514
A strong emission line at 6703A has been detected in the optical spectrum for
the host galaxy (R=23.1) of the radio source RC J0311+0507 (4C+04.11). This
radio galaxy, with a spectral index of 1.31 in the frequency range 365-4850
MHz, is one of the ultrasteep spectrum objects from the deep survey of a sky
strip conducted with RATAN-600 in 1980-1981. We present arguments in favor of
the identification of this line with Ly\alpha at redshift z=4.514. In this
case, the object belongs to the group of extremely distant radio galaxies of
ultrahigh radio luminosity (P_{1400}=1.3 x 10^{29}W Hz^{-1}). Such power can be
provided only by a fairly massive black hole (~10^9M_\sun}) that formed in a
time less than the age of the Universe at the observed z(1.3 Gyr) or had a
primordial origin.Comment: 8 pages, 3 figure
NCBI GEO: archive for functional genomics data sets—10 years on
A decade ago, the Gene Expression Omnibus (GEO) database was established at the National Center for Biotechnology Information (NCBI). The original objective of GEO was to serve as a public repository for high-throughput gene expression data generated mostly by microarray technology. However, the research community quickly applied microarrays to non-gene-expression studies, including examination of genome copy number variation and genome-wide profiling of DNA-binding proteins. Because the GEO database was designed with a flexible structure, it was possible to quickly adapt the repository to store these data types. More recently, as the microarray community switches to next-generation sequencing technologies, GEO has again adapted to host these data sets. Today, GEO stores over 20 000 microarray- and sequence-based functional genomics studies, and continues to handle the majority of direct high-throughput data submissions from the research community. Multiple mechanisms are provided to help users effectively search, browse, download and visualize the data at the level of individual genes or entire studies. This paper describes recent database enhancements, including new search and data representation tools, as well as a brief review of how the community uses GEO data. GEO is freely accessible at http://www.ncbi.nlm.nih.gov/geo/
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