99 research outputs found
Radioastron flight operations
Radioastron is a space-based very-long-baseline interferometry (VLBI) mission to be operational in the mid-90's. The spacecraft and space radio telescope (SRT) will be designed, manufactured, and launched by the Russians. The United States is constructing a DSN subnet to be used in conjunction with a Russian subnet for Radioastron SRT science data acquisition, phase link, and spacecraft and science payload health monitoring. Command and control will be performed from a Russian tracking facility. In addition to the flight element, the network of ground radio telescopes which will be performing co-observations with the space telescope are essential to the mission. Observatories in 39 locations around the world are expected to participate in the mission. Some aspects of the mission that have helped shaped the flight operations concept are: separate radio channels will be provided for spacecraft operations and for phase link and science data acquisition; 80-90 percent of the spacecraft operational time will be spent in an autonomous mode; and, mission scheduling must take into account not only spacecraft and science payload constraints, but tracking station and ground observatory availability as well. This paper will describe the flight operations system design for translating the Radioastron science program into spacecraft executed events. Planning for in-orbit checkout and contingency response will also be discussed
Giant Pulses from PSR B1937+21 with widths <= 15 nanoseconds and T_b >= 5 x 10^39 K, the Highest Brightness Temperature Observed in the Universe
Giant radio pulses of the millisecond pulsar B1937+21 were recorded with the
S2 VLBI system at 1.65 GHz with NASA/JPL's 70-m radio telescope at Tidbinbilla,
Australia. These pulses have been observed as strong as 65000 Jy with widths <=
15 ns, corresponding to a brightness temperature T_b >= 5 x 10^39 K, the
highest observed in the universe. The vast majority of these pulses occur in a
5.8 mcs and 8.2 mcs window at the very trailing edges of the regular main pulse
and interpulse profiles, respectively. Giant pulses occur in general with a
single spike. Only in one case out of 309 was the structure clearly more
complex. The cumulative distribution is fit by a power law with index -1.40 +/-
0.01 with a low-energy but no high-energy cutoff. We estimate that giant pulses
occur frequently but are only rarely detected. When corrected for the
directivity factor, 25 giant pulses are estimated to be generated in one
neutron star revolution alone. The intensities of the giant pulses of the main
pulses and interpulses are not correlated with each other nor with the
intensities or energies of the main pulses and interpulses themselves. Their
radiation energy density can exceed 300 times the plasma energy density at the
surface of the neutron star and can even exceed the magnetic field energy
density at that surface. We therefore do not think that the generation of giant
pulses is linked to the plasma mechanisms in the magnetosphere. Instead we
suggest that it is directly related to discharges in the polar cap region of
the pulsar.Comment: 14 pages, 13 figures, to be published in ApJ, November 2004, v. 616,
also was presented in Russian National Astronomical Conference VAK-2004,
"Horizons of the Universe" held in Moscow State University, Sternberg
Astronomical Institute, June 3-10, 2004, page 19
МУКОЛИТИКИ В ТЕРАПИИ БРОНХОЛЕГОЧНОЙ ДИСПЛАЗИИ
Mucolytic drugs, particularly, direct action mucolytics with acetylcysteine derivatives among them, are included in the complex therapy of the bronchopulmonary dysplasia exacerbations. However, data on application effectiveness and safety of such a therapy with chronic bronchopulmonary diseases in children of 0–2 years of age are few and contradictory. The article contains proprietary clinical functional data on application of acetylcysteine in granules for the syrup preparation in the treatment of children bronchopulmonary dysplasia.В комплексную терапию обострений бронхолегочной дисплазии наряду с ингаляционными кортикостероидами и антибиотиками входят муколитические препараты, в частности муколитики прямого действия, к которым относятся производные ацетилцистеина. Однако, данные об эффективности и безопасности применения такой терапии при хронических бронхолегочных заболеваниях у детей первых двух лет жизни малочисленны и разноречивы. Статья содержит собственные клинико-функциональные данные о применении ацетилцистеина в гранулах для приготовления сиропа при лечении детей с бронхолегочной дисплазией.
Total linear polarization in the OH maser W75N: VLBA polarization structure
W75N is a star-forming region containing various ultracompact HII regions and
OH, water, and methanol maser emission. Our VLBA map shows that the OH masers
are located in a thin disk rotating around an O-star which is the exciting star
of the ultracompact HII region VLA1. A separate set of maser spots is connected
with the ultracompact HII region VLA2. The radial velocity of OH maser spots
varies across the disk from 3.7 km/s to 10.9 km/s. The diameter of the disk is
4000 A.U. All maser spots are strongly polarized. This are the first OH masers
showing nearly 100 per cent linear polarization in several spots. Two maser
spots seem to be Zeeman pairs corresponding to a magnetic field of 5.2 mgauss
and 7.7 mgauss, and in one case we tentatively found a Zeeman pair consisting
of two linearly polarized components. The linearly polarized maser spots are
shown to be sigma-components which is the case of the magnetic field being
perpendicular to the line of sight. The direction of the magnetic field as
determined from linearly polarized spots is perpendicular to the plane of the
disk, although the galactic Faraday rotation may significantly affect this
conclusion.Comment: 14 figures, 1 table, 27 pages. accepted for publication in ApJ,
scheduled for v.564, N1, 200
Space-VLBI observations of OH maser OH34.26+0.15: low interstellar scattering
We report on the first space-VLBI observations of the OH34.26+0.15 maser in
two main line OH transitions at 1665 and 1667 MHz. The observations involved
the space radiotelescope on board the Japanese satellite HALCA and an array of
ground radio telescopes. The map of the maser region and images of individual
maser spots were produced with an angular resolution of 1 milliarcsec which is
several times higher than the angular resolution available on the ground. The
maser spots were only partly resolved and a lower limit to the brightness
temperature 6x10^{12} K was obtained. The maser seems to be located in the
direction of low interstellar scattering, an order of magnitude lower than the
scattering of a nearby extragalactic source and pulsar.Comment: 8 pages, 2 tables, 9 figures, accepted for publication in MNRA
Pulsar microstructure and its quasi-periodicities with the S2 VLBI system at a resolution of 62.5 nanoseconds
We report on a study of microstructure and its quasi-periodicities of three
pulsars at 1.65 GHz with the S2 VLBI system at a resolution of 62.5 ns, by far
the highest for any such statistical study yet. For PSR B1929+10 we found in
the average cross-correlation function (CCF) broad microstructure with a
characteristic timescale of 95+-10 mcs and confirmed microstructure with
characteristic timescales between 100 and 450 mcs for PSRs B0950+08 and
B1133+16. On a finer scale PSRs B0950+08, B1133+16 (component II) and B1929+10
show narrow microstructure with a characteristic timescale in the CCFs of ~10
mcs, the shortest found in the average CCF or autocorrelation function (ACF)
for any pulsar, apart perhaps for the Crab pulsar. Histograms of microstructure
widths are skewed heavily toward shorter timescales but display a sharp cutoff.
The shortest micropulses have widths between 2 and 7 mcs. No nanopulses or
unresolved pulse spikes were detected. Cross-power spectra of single pulses
show a large range of complexity with single spectral features representing
classic quasi-periodicities and broad and overlapping features with essentially
no periodicities at all. Significant differences were found for the two
components of PSR B1133+16 in every aspect of our statistical analysis of
micropulses and their quasi-periodicities. Asymmetries in the magnetosphere and
the hollow cone of emission above the polar cap of the neutron star may be
responsible for these differences.Comment: 18 pages, 11 figures, 3 tables, A&A, 2001, accepte
ИММУНОПРОФИЛАКТИКА ТЯЖЕЛОГО ТЕЧЕНИЯ РЕСПИРАТОРНО-СИНЦИТИАЛЬНОЙ ВИРУСНОЙ ИНФЕКЦИИ У ДЕТЕЙ С БРОНХОЛЕГОЧНОЙ ДИСПЛАЗИЕЙ: РЕЗУЛЬТАТЫ ЧЕТЫРЕХ ЭПИДЕМИЧЕСКИХ СЕЗОНОВ
Children with bronchopulmonary dysplasia belong to the risk group of severe respiratory-syncytial viral infection (RSV). World experience and authors' own clinical data show that seasonal immunoprophylaxis of RSV infection's severe course by palivizumab in these patients allows reducing frequency of hospitalizations, CPR conduct and fatal outcomes. The article gives data of clinical instrumental evaluation of efficacy and safety of palivizumab use in the 3 past and the 4th (current) epidemic seasons.Дети с бронхолегочной дисплазией относятся к группе риска тяжелого течения респираторно-синцитиальной вирусной (РСВ) инфекции. Мировой опыт и собственные клинические данные показывают, что сезонная иммунопрофилактика тяжелого течения РСВ инфекции паливизумабом у этих больных позволяет уменьшить частоту госпитализаций, проведения реанимационных мероприятий и летальных исходов. В статье представлены данные клинико-инструментальной оценки эффективности и безопасности применения препарата паливизумаб в течение трех прошедших и четвертого текущего эпидемических сезонов.
Влияние ферментозаместительной терапии на обструкцию верхних дыхательных путей у детей с мукополисахаридозами: ретроспективное когортное исследование
Background. Data on the efficacy of enzyme replacement therapy (ERT) in relation to the pathology of ENT organs and respiratory performance in sleep in children with mucopolysaccharidosis (MPS) is poorly presented in the literature. Our aim was to assess the effect of ERT on the upper respiratory tract in children with MPS. Methods. According to the case histories, we studied treatment results of children with MPS type I and II who received ERT in the Research Center of Children’s Health from January 2007 to November 2016. The severity of upper airway obstruction and its change during ERT was assessed according to indices of apnea-hypopnea and desaturation (SpO2), average/minimal SpO2, duration of SpO2 episodes < 90%, and hypertrophy degree of palatine tonsils and adenoids. Results. The severity of the obstructive sleep apnea syndrome did not progress in children (n = 15) with MPS against the background of ERT with a median duration of 38 (23; 48) months: initially, the apnea-hypopnea index was 3 (1.3; 7.7), while the repeated study — 2.6 (0.9; 13.5) (p = 0.507). There was also no statistically significant change in cardiorespiratory monitoring values. Conclusion. Long-term ERT in children with MPS type I and II interferes with the progression of airway obstruction.Обоснование. Данные об эффективности ферментозаместительной терапии (ФЗТ) в отношении патологии ЛОР- органов и показателей дыхания во сне у детей с мукополисахаридозом (МПС) в литературе представлены скудно.Цель исследования — оценить влияние ФЗТ на состояние верхних дыхательных путей у детей с МПС.Методы. По историям болезни изучали результаты лечения детей с МПС I и II типов, получавших ФЗТ в Научном центре здоровья детей (ныне ФГАУ «НМИЦ здоровья детей» Минздрава России) с января 2007 по ноябрь 2016 г. Выраженность обструкции верхних дыхательных путей и ее изменение на фоне ФЗТ оценивали по индексам апноэ-гипопноэ и десатурации (SpO2), средней/минимальной SpO2, продолжительности эпизодов SpO2< 90% и степени гипертрофии небных миндалин и аденоидов.Результаты. У детей (n=15) с МПС на фоне ФЗТ продолжительностью (медиана) 38 (23; 48) мес тяжесть синдрома обструктивного апноэ сна не прогрессировала: исходно индекс апноэ-гипопноэ составил 3 (1,3; 7,7), при повторном исследовании — 2,6 (0,9; 13,5) (р=0,507). Также не установлено статистически значимого изменения показателей кардиореспираторного мониторинга.Заключение. Длительная ФЗТ у детей с МПС I и II типов препятствует прогрессированию обструкции дыхательных путей.КОНФЛИКТ ИНТЕРЕСОВ Л.С. Намазова-Баранова — получение исследовательских грантов от фармацевтических компаний Пьер Фабр, Genzyme Europe B. V., ООО «Астра зенека Фармасьютикалз», Gilead / PRA «Фармасьютикал Рисерч Ассошиэйтс СиАйЭс», Bionorica, Teva Branded Pharmaceutical products R&D, Inc / ООО «ППД Девелопмент (Смоленск)», «Сталлержен С. А.» / «Квинтайлс ГезмбХ» (Австрия). Л.М. Кузенкова, А.К. Геворкян, Т.В. Подклетнова, Н.Д. Вашакмадзе читают лекции для компаний «Санофи Джензайм», «Шайер», «Биомарин». Остальные авторы подтвердили отсутствие конфликта интересов, о котором необходимо сообщить
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