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Your search keyword '"Konovalenko, O. O."' showing total 8 results
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8 results on '"Konovalenko, O. O."'

1. Dual-frequency single-pulse study of PSR B0950+08

Author

Bilous, A. V., Griessmeier, J. M., Pennucci, T., Wu, Z., Bondonneau, L., Kondratiev, V., van Leeuwen, J., Maan, Y., Connor, L., Oostrum, L. C., Petroff, E., Verbiest, J. P. W., Vohl, D., McKee, J. W., Shaifullah, G., Theureau, G., Ulyanov, O. M., Cecconi, B., Coolen, A. H., Corbel, S., Damstra, S., Denes, H., Girard, J. N., Hut, B., Ivashina, M., Konovalenko, O. O., Kutkin, A., Loose, G. M., Mulder, H., Ruiter, M., Smits, R., Tokarsky, P. L., Vermaas, N. J., Zakharenko, V. V., Zarka, P., and Ziemke, J.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract

PSR B0950+08 is a bright non-recycled pulsar whose single-pulse fluence variability is reportedly large. Based on observations at two widely separated frequencies, 55 MHz (NenuFAR) and 1.4 GHz (Westerbork Synthesis Radio Telescope), we review the properties of these single pulses. We conclude that they are more similar to ordinary pulses of radio emission than to a special kind of short and bright Giant Pulses, observed from only a handful of pulsars. We argue that temporal variation of properties of interstellar medium along the line of sight to this nearby pulsar, namely the fluctuating size of decorrelation bandwidth of diffractive scintillation makes important contribution to observed single-pulse fluence variability. We further present interesting structures in the low-frequency single-pulse spectra that resemble the "sad trombones" seen in Fast Radio Bursts (FRBs); although for PSR B0950+08 the upward frequency drift is also routinely present. We explain these spectral features with radius-to-frequency mapping, similar to the model developed by Wang et al. (2019) for FRBs. Finally, we speculate that microsecond-scale fluence variability of the general pulsar population remains poorly known, and that its further study may bring important clues about the nature of FRBs., Comment: Accepted by A&A. This version includes a number of minor corrections, including corrected FRB luminosities on the time-luminosity phase-space plot for radio pulses from neutron stars and repeating FRBs

Published
2021
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2. Dual-frequency single-pulse study of PSR B0950+08

Author

Bilous, A. V., primary, Grießmeier, J. M., additional, Pennucci, T., additional, Wu, Z., additional, Bondonneau, L., additional, Kondratiev, V., additional, van Leeuwen, J., additional, Maan, Y., additional, Connor, L., additional, Oostrum, L. C., additional, Petroff, E., additional, Verbiest, J. P. W., additional, Vohl, D., additional, McKee, J. W., additional, Shaifullah, G., additional, Theureau, G., additional, Ulyanov, O. M., additional, Cecconi, B., additional, Coolen, A. H., additional, Corbel, S., additional, Damstra, S., additional, Dénes, H., additional, Girard, J. N., additional, Hut, B., additional, Ivashina, M., additional, Konovalenko, O. O., additional, Kutkin, A., additional, Loose, G. M., additional, Mulder, H., additional, Ruiter, M., additional, Smits, R., additional, Tokarsky, P. L., additional, Vermaas, N. J., additional, Zakharenko, V. V., additional, Zarka, P., additional, and Ziemke, J., additional

Published
2022
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4. DECAMETER PULSARS AND TRANSIENTS SURVEY OF THE NORTHERN SKY. STATUS, FIRST RESULTS, MULTIPARAMETRIC PIPELINE FOR CANDIDATE SELECTION

Author

Zakharenko, V. V.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Kravtsov, I. P.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Vasylieva, I. Y.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine; Universite Paris Diderot, Mykhailova, S. S.; V. N. Karazin Kharkiv National University, Ulyanov, O. M.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Shevtsova, A. I.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Skoryk, A. O.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Zarka, P.; LESIA, Konovalenko, O. O.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Zakharenko, V. V.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Kravtsov, I. P.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Vasylieva, I. Y.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine; Universite Paris Diderot, Mykhailova, S. S.; V. N. Karazin Kharkiv National University, Ulyanov, O. M.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Shevtsova, A. I.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Skoryk, A. O.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, Zarka, P.; LESIA, and Konovalenko, O. O.; Institute of Radio Astronomy of the National Academy of Sciences of Ukraine

Abstract

We present the results of processing first 20% of Northern sky pulsars and transients survey using UTR-2 radio telescope. Data processing is done by an automatic pipeline that detects and outputs a large number of transient candidates (usually dispersed bursts). We have developed a multivariate pipeline for visual inspection of these candidates. By adjustment of input parameters of the pipeline the observer can substantially increase signal-to-noise ratio of detected signals as well as discriminate them from residual low-intensity interference with high significance. About 450 transient signals have passed the examination by the multivariate pipeline. Their distributions on the Galactic latitude and dispersion measure have been derived. The shape of the distributions suggests that these signals might be associated with cosmic sources of radio emission.

Published
2016

7. [Age-related characteristics of experimental hypothyroidism in rats].

Author

Hromakova IA, Zil'berman STs, and Konovalenko OO

Subjects
Animals, Blood Proteins metabolism, Disease Models, Animal, Liver enzymology, Liver metabolism, Male, Protein Biosynthesis, RNA Polymerase I metabolism, RNA Polymerase II metabolism, Rats, Rats, Wistar, Aging, Hypothyroidism physiopathology
Abstract

The rate of both the synthesis of liver and plasma proteins and RNA-1 and RNA-2 polymerase activities in liver were studied in rats of various ages at experimental hypothyroidism. There has been marked more significant decrease in plasma protein synthesis with age. Both the rate of liver and plasma protein synthesis have been shown to be reduced at experimental hypothyroidism but synthesis of plasma proteins was inhibited to a greater extent. Considerable changes were observed neither in liver and plasma protein synthesis nor in the balance between these two groups of the protein synthesis in old rats. RNA-1 and RNA-2 polymerase activities decreased at hypothyroidism. At all ages the activity of bound enzymes decreased to a larger extent as compared to free forms. The activity of RNA-polymerase 2 was more inhibited than that of RNA-polymerase 1. Reducing protein- and RNA-synthetic processes in the liver with age correlated with the peculiarities of the carbohydrate metabolism: in those young animals with an impaired glucose tolerance the inhibitory effect of hypothyroidism on the intensity of protein and RNA synthesis was more potent as compared to old animals.

Published
2002

8. [State of the endocrine system in rats of various ages under immobilization stress and influence of adaptogenic biomos].

Author

Alesina MIu, Sukachova OO, Zilberman STs, Konovalenko OO, Nesterenko GO, and Beskrovnyĭ OM

Subjects
Animals, Animals, Newborn, Corticosterone blood, Endocrine Glands physiology, Insulin blood, Male, Rats, Rats, Wistar, Restraint, Physical, Thyroxine blood, Triiodothyronine blood, Blood Glucose drug effects, Endocrine Glands drug effects, Humic Substances pharmacology, Plant Extracts pharmacology, Thyroxine drug effects, Triiodothyronine drug effects
Abstract

The effect of administration, of BIOMOS-VJ on the concentration of thyroxine, triiodothyronine, corticosterone, insulin and glucose in the blood serum of the normal state and under conditions of immobilization stress of young and aged Wistar's rats has been studied. The experiments have shown that the administration of preparation prevents the appearance of disturbances in endocrine system of the organism typical of stress such as a decrease in concentration of thyroid hormones and insulin and also a considerable increase in corticosterone and glucose concentration in the blood serum. On the basis of the results indicating the influence of BIOMOS-VJ on the endocrine system of young and aged Wistar's rats it is assumed that this preparation has gero-protected properties.

Published
1993

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