131 research outputs found
Detection of Giant Pulses from the Pulsar PSR B0031-07
Giant pulses have been detected from the pulsar PSR B0031-07. A pulse with an
intensity higher than the intensity of the average pulse by a factor of 50 or
more is encountered approximately once per 300 observed periods. The peak flux
density of the strongest pulse is 530 Jy, which is a factor of 120 higher than
the peak flux density of the average pulse. The giant pulses are a factor of 20
narrower than the integrated profile and are clustered about its center.Comment: 7 pages, 2 figures, to appear in: Pis'ma v Astronomicheskii Zhurnal,
2004, v.30, No.4, and will be translated as: Astronomy Letters, v.30, No.
Instantaneous Radio Spectra of Giant Pulses from the Crab Pulsar from Decimeter to Decameter Wavelengths
The results of simultaneous multifrequency observations of giant radio pulses
from the Crab pulsar, PSR B0531+21, at 23, 111, and 600 MHz are presented and
analyzed. Giant pulses were detected at a frequency as low as 23 MHz for the
first time. Of the 45 giant pulses detected at 23 MHz, 12 were identified with
counterparts observed simultaneously at 600 MHz. Of the 128 giant pulses
detected at 111 MHz, 21 were identified with counterparts observed
simultaneously at 600 MHz. The spectral indices for the power-law frequency
dependence of the giant-pulse energies are from -3.1 to -1.6. The mean spectral
index is -2.7 +/- 0.1 and is the same for both frequency combinations (600-111
MHz and 600-23 MHz). The large scatter in the spectral indices of the
individual pulses and the large number of unidentified giant pulses suggest
that the spectra of the individual giant pulses do not actually follow a simple
power law. The observed shapes of the giant pulses at all three frequencies are
determined by scattering on interstellar plasma irregularities. The scatter
broadening of the pulses and its frequency dependence were determined as
tau_sc=20*(f/100)^(-3.5 +/- 0.1) ms, where the frequency f is in MHz.Comment: 13 pages, 1 figure, 1 table (originally published in Russian in
Astronomicheskii Zhurnal, 2006, vol. 83, No. 7, pp. 630-637), translated by
Georgii Rudnitski
Difficulties in diagnosing intestinal T-cell lymphoma. Case report
The article describes a rare diagnosis of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), due to its veiled by a number of so-called masks of enteropathies. A detailed analysis of all clinical, morphological and immunohistochemical data made it possible to establish the correct diagnosis. The revealed pathology is extremely rare in practice, even among specialists in hematology. The article demonstrates the main stages of both a complex diagnosis and an attempt at therapy for this aggressive form of intestinal lymphoma
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