769 research outputs found
INTEGRAL and XMM-Newton observations of IGR J16418-4532: evidence of accretion regime transitions in a supergiant fast X-ray transient
No full textWe report on combined INTEGRAL and XMM–Newton observations of the supergiant fast X-ray transient (SFXT) IGR J16418-4532. The observations targeted the X-ray eclipse region of IGR J16418-4532's orbit with continuous INTEGRAL observations across ~25 per cent of orbital phase and two quasi-simultaneous XMM–Newton observations of length 20 and 14 ks, occurring during and just after the eclipse, respectively. An enhanced INTEGRAL emission history is provided with 19 previously unreported outbursts identified in the archival 18–60 keV data set. The XMM–Newton eclipse observation showed prominent Fe emission and a flux of 2.8 × 10-13 erg cm-2 s-1 (0.5–10 keV). Through the comparison of the detected eclipse and post-eclipse flux, the supergiant mass-loss rate through the stellar wind was determined as Ṁw = 2.3–3.8 × 10-7 M⊙ yr-1. The post-eclipse XMM–Newton observation showed a dynamic flux evolution with signatures of the X-ray pulsation, a period of flaring activity, structured nH variations and the first ever detection of an X-ray intensity dip, or ‘off-state’, in a pulsating SFXT. Consideration is given to the origin of the X-ray dip, and we conclude that the most applicable of the current theories of X-ray dip generation is that of a transition between Compton-cooling-dominated and radiative-cooling-dominated subsonic accretion regimes within the ‘quasi-spherical’ model of wind accretion. Under this interpretation, which requires additional confirmation, the neutron star in IGR J16418-4532 possesses a magnetic field of ~1014 G, providing tentative observational evidence of a highly magnetized neutron star in a SFXT for the first time. The implications of these results on the nature of IGR J16418-4532 itself and the wider SFXT class are discussed
Correlated X-ray/ultraviolet/optical variability in the very low mass AGN NGC 4395
No full textWe report the results of a 1-yr Swift X-ray/ultraviolet (UV)/optical programme monitoring the dwarf Seyfert nucleus in NGC4395 in 2008-2009. The UV/optical flux from the nucleus was found to vary dramatically over the monitoring period, with a similar pattern of variation in each of the observed UV/optical bands (spanning 1900-5500 Å). In particular, the luminosity of NGC4395 in the 1900 Å band changed by more than a factor of 8 over the monitoring period. The fractional variability was smaller in the UV/optical bands than that seen in the X-rays, with the X-ray/optical ratio increasing with increasing flux. Pseudo-instantaneous flux measurements in the X-ray and each UV/optical band were well correlated, with cross-correlation coefficients of ≥0.7, significant at 99.9per cent confidence. Archival Swift observations from 2006 sample the intra-day X-ray/optical variability on NGC4395. These archival data show a very strong correlation between the X-ray and b bands, with a cross-correlation coefficient of 0.84 (significant at >99per cent confidence). The peak in the cross-correlation function is marginally resolved and asymmetric, suggesting that X-rays lead the b band, but by ≤1h. In response to recent (2011 August) very high X-ray flux levels from NGC4395 we triggered Swift target of opportunity observations, which sample the intra-hour X-ray/UV variability. These observations indicate, albeit with large uncertainties, a lag of the 1900 Å band behind the X-ray flux of ∼400s. The tight correlation between the X-ray and UV/optical lightcurves, together with the constraints we place on the lag time-scale, is consistent with the UV/optical variability of NGC4395 being primarily due to reprocessing of X-ray photons by the accretion disc
Determination of X-ray pulsar geometry with IXPE polarimetry
No full textFull list of authors: Doroshenko, Victor; Poutanen, Juri; Tsygankov, Sergey S.; Suleimanov, Valery F.; Bachetti, Matteo; Caiazzo, Ilaria; Costa, Enrico; Di Marco, Alessandro; Heyl, Jeremy; La Monaca, Fabio; Muleri, Fabio; Mushtukov, Alexander A.; Pavlov, George G.; Ramsey, Brian D.; Rankin, John; Santangelo, Andrea; Soffitta, Paolo; Staubert, Rüdiger; Weisskopf, Martin C.; Zane, Silvia; Agudo, Iván; Antonelli, Lucio A.; Baldini, Luca; Baumgartner, Wayne H.; Bellazzini, Ronaldo; Bianchi, Stefano; Bongiorno, Stephen D.; Bonino, Raffaella; Brez, Alessandro; Bucciantini, Niccolò; Capitanio, Fiamma; Castellano, Simone; Cavazzuti, Elisabetta; Ciprini, Stefano; De Rosa, Alessandra; Del Monte, Ettore; Di Gesu, Laura; Di Lalla, Niccolò; Donnarumma, Immacolata; Dovčiak, Michal; Ehlert, Steven R.; Enoto, Teruaki; Evangelista, Yuri; Fabiani, Sergio; Ferrazzoli, Riccardo; Garcia, Javier A.; Gunji, Shuichi; Hayashida, Kiyoshi; Iwakiri, Wataru; Jorstad, Svetlana G.; Karas, Vladimir; Kitaguchi, Takao; Kolodziejczak, Jeffery J.; Krawczynski, Henric; Latronico, Luca; Liodakis, Ioannis; Maldera, Simone; Manfreda, Alberto; Marin, Frédéric; Marinucci, Andrea; Marscher, Alan P.; Marshall, Herman L.; Matt, Giorgio; Mitsuishi, Ikuyuki; Mizuno, Tsunefumi; Ng, Chi-Yung; O'Dell, Stephen L.; Omodei, Nicola; Oppedisano, Chiara; Papitto, Alessandro; Peirson, Abel L.; Perri, Matteo; Pesce-Rollins, Melissa; Pilia, Maura; Possenti, Andrea; Puccetti, Simonetta; Ratheesh, Ajay; Romani, Roger W.; Sgrò, Carmelo; Slane, Patrick; Spandre, Gloria; Sunyaev, Rashid A.; Tamagawa, Toru; Tavecchio, Fabrizio; Taverna, Roberto; Tawara, Yuzuru; Tennant, Allyn F.; Thomas, Nicolas E.; Tombesi, Francesco; Trois, Alessio; Turolla, Roberto; Vink, Jacco; Wu, Kinwah; Xie, Fei.Using observations of X-ray pulsar Hercules X-1 by the Imaging X-ray Polarimetry Explorer we report a highly significant (>17σ) detection of the polarization signal from an accreting neutron star. The observed degree of linear polarization of ~10% is far below theoretical expectations for this object, and stays low throughout the spin cycle of the pulsar. Both the degree and angle of polarization exhibit variability with the pulse phase, allowing us to measure the pulsar spin position angle 57(2) deg and the magnetic obliquity 12(4) deg, which is an essential step towards detailed modelling of the intrinsic emission of X-ray pulsars. Combining our results with the optical polarimetric data, we find that the spin axis of the neutron star and the angular momentum of the binary orbit are misaligned by at least ~20 deg, which is a strong argument in support of the models explaining the stability of the observed superorbital variability with the precession of the neutron star. © 2022, The Author(s), under exclusive licence to Springer Nature Limited.This Article is based on observations made by IXPE, a joint US and Italian mission. This research used data products provided by the IXPE Team (MSFC, SSDC, INAF and INFN) and distributed with additional software tools by the High-Energy Astrophysics Science Archive Research Center (HEASARC), at the NASA Goddard Space Flight Center (GSFC). The US contribution is supported by NASA and led and managed by its Marshall Space Flight Center (MSFC), with industry partner Ball Aerospace (contract number NNM15AA18C). The Italian contribution is supported by the Italian Space Agency (Agenzia Spaziale Italiana, ASI) through contract number ASI-OHBI-2017-12-I.0, agreement numbers ASI-INAF-2017-12-H0 and ASI-INFN-2017.13-H0, and its Space Science Data Center (SSDC) and by the Istituto Nazionale di Astrofisica (INAF) and the Istituto Nazionale di Fisica Nucleare (INFN) in Italy. V.D. and V.F.S. acknowledge support from the German Academic Exchange Service (DAAD) under travel grant number 57525212. J.P. and S.S.T. thank the Russian Science Foundation for support under grant number 20-12-00364 and the Academy of Finland for support under grant numbers 333112, 349144, 349373 and 349906. V.F.S. thanks the German Research Foundation (DFG) for grant number WE 1312/53-1. I.C. is a Sherman Fairchild Fellow at Caltech and thanks the Burke Institute at Caltech for supporting her research. A.A.M. acknowledges support from the Netherlands Organization for Scientific Research Veni Fellowship.info:eu-repo/grantAgreement/MICINN//SEV-2017-0709Peer reviewe
Super spin-glass state in two-dimensional aggregated Fe3 O4 nanoparticles deposited on a plasma-treated polymeric substrate
No full textThe assembly consisting of Fe3O4 nanoparticles deposited on a plasma-treated polypropylene substrate was structurally characterized and its static and dynamic magnetic properties were investigated. The Fe3O4 nanoparticles of the nominal size of 10 nm create agglomerates of the size ranging from nominally 10 to 400 nm which were deposited on the polypropylene substrate using the grafting technique. The behavior of zero field cooled and field cooled susceptibility was found to be consistent with the onset of the super spin-glass state with glassy temperature Tg=211K. The formation of the super spin-glass state was also supported by the relative shift of maximum in alternating susceptibility Γ ≈ 0.06 and zɛ=8.6 obtained from critical slowing down analysis as well as by the study of memory and aging effects. Significant renormalization of Tg and zυ for obtaining universal behavior in dynamic scaling of alternating susceptibility is tentatively ascribed to deviation toward two-dimensional magnetic behavior. The obtained results suggest that the studied assembly may be appropriate for the realization of unique two-dimensional super spin glass with dominant dipolar interaction
Extracellular DNA impedes the transport of vancomycin in Staphylococcus epidermidis biofilms pre-exposed to sub-inhibitory concentrations of vancomycin
No full textStaphylococcus epidermidis biofilm formation is responsible for the persistence of orthopaedic implant infections. Previous studies have shown that exposure of S. epidermidis biofilms to sub-minimum inhibitory concentrations (sub-MIC) of antibiotics induced an increased level of biofilm persistence. BODIPY FL-vancomycin (a fluorescent vancomycin conjugate) and confocal microscopy were used to show that the penetration of vancomycin through sub-MIC vancomycin treated S. epidermidis biofilms was impeded, when compared to control, untreated biofilms. Further experiments showed an increase in the eDNA concentration in biofilms pre-exposed to sub-MIC vancomycin, suggesting a potential role for eDNA in the hindrance of vancomycin activity. Exogenously added, S. epidermidis DNA increased planktonic vancomycin MIC and protected biofilm cells from lethal vancomycin concentrations. Finally, isothermal titration calorimetry (iTC) revealed that the binding constant of DNA and vancomycin was 100-fold higher, than the previously reported, binding constant of vancomycin and its intended cellular D-Ala-D-Ala peptide target. This study provides an explanation of the eDNA-based mechanism of antibiotic tolerance in sub-MIC vancomycin treated S. epidermidis biofilms, which might be an important factor for the persistence of biofilm infections
Якість життя за EQ-5D-5L та особливості її динаміки в пацієнтів ортопедичного профілю амбулаторної програми фізичної терапії
No full textQuality of life using the EQ-5D-5L and the features of its dynamics among the orthopedic profile patients in outpatient program of physical therapy / S. М. Fedorenko, V. V. Vitomskyi, O. B. Lazarіeva, E. Yu. Doroshenko, M. V. Vitomska, I. V. Onopriienko // Zaporozhye medical journal. - 2020. - Vol. 22. - № 3. - P. 315-322.Мета роботи – визначити рівень якості життя в амбулаторних пацієнтів із порушеннями ортопедичного профілю та дослідити її динаміку за курс фізичної терапії залежно від локалізації порушення та психотипу.
Матеріали та методи. У досліджені взяли участь 113 пацієнтів, котрі надходили на курс фізичної терапії в медичному
центрі «ФЕСКО» впродовж 2013–2015 рр. Пацієнтів групували за локалізацією порушення та психотипом ставлення до
хвороби. Якість життя оцінювали за опитувальником EQ-5D-5L. Курс фізичної терапії складався з 12–15 занять (40–60 хв;
терапевтичні фізичні вправи та механотерапія за комплексом, що призначений лікарем), фізіопроцедур (магнітотерапія,
електроміостимуляція за призначенням лікаря) та масажу (7–8 процедур). Тривалість курсу – 5–6 тижнів.
Результати. Виявили статистично гірші початкові результати в пацієнтів із порушеннями в попереку, поясі нижньої кінцівки
та самої вільної кінцівки у шкалах «мобільність», «біль/дискомфорт» і ВАШ порівняно з пацієнтами з порушеннями у верхній
частині тіла. Під час поділу пацієнтів залежно від психотипу отримали відмінності у шкалах «тривога/депресія» та ВАШ.
У пацієнтів із раціональним ставленням до хвороби аналіз показав кращу динаміку та остаточні результати за шкалою
«тривога/депресія» порівняно з групою нераціональних психотипів. У динаміці за іншими шкалами також спостерігали
перевагу в пацієнтів із раціональним ставленням до хвороби, але вони не були вірогідними.
Висновки. Результати свідчать: не тільки локалізація, але й особливості ставлення до хвороби впливають на якість
життя та результативність фізичної терапії. Перспективи дальших досліджень полягають у визначенні шляхів покращення динаміки шляхом впровадження нових засобів фізичної терапії та методик їхнього використання, методів
управління процесом фізичної терапії
The awakening of BL Lacertae: observations by Fermi, Swift and the GASP-WEBT
No full textSince the launch of the Fermi satellite, BL Lacertae has been moderately active at ?-rays and optical frequencies until 2011 May, when the source started a series of strong flares. The exceptional optical sampling achieved by the GLAST–AGILE Support Program of the Whole Earth Blazar Telescope in collaboration with the Steward Observatory allows us to perform a detailed comparison with the daily γ-ray observations by Fermi. Discrete correlation analysis between the optical and γ-ray emission reveals correlation with a time lag of 0 ± 1 d, which suggests cospatiality of the corresponding jet emitting regions. A better definition of the time lag is hindered by the daily gaps in the sampling of the extremely fast flux variations. In general, optical flares present more structure and develop on longer time-scales than corresponding γ-ray flares. Observations at X-rays and at millimetre wavelengths reveal a common trend, which suggests that the region producing the mm and X-ray radiation is located downstream from the optical and γ-ray-emitting zone in the jet. The mean optical degree of polarization slightly decreases over the considered period and in general it is higher when the flux is lower. The optical electric vector polarization angle (EVPA) shows a preferred orientation of about 15°, nearly aligned with the radio core EVPA and mean jet direction. Oscillations around it increase during the 2011–2012 outburst. We investigate the effects of a geometrical interpretation of the long-term flux variability on the polarization. A helical magnetic field model predicts an evolution of the mean polarization that is in reasonable agreement with the observations. These can be fully explained by introducing slight variations in the compression factor in a transverse shock waves model
Long-term optical and X-ray variability of the Seyfert galaxy Markarian 79
No full textWe present the results of concurrent X-ray and optical monitoring of the Seyfert 1 galaxy Mrk 79 over a period of more than 5 yr. We find that on short to medium time-scales (days to a few tens of days) the 2–10 keV X-ray and optical u- and V-band fluxes are significantly correlated, with a delay between the bands consistent with 0 d. We show that most of these variations may be well reproduced by a model where the short-term optical variations originate from reprocessing of X-rays by an optically thick accretion disc. The optical light curves, however, also display long time-scale variations over thousands of days, which are not present in the X-ray light curve. These optical variations must originate from an independent variability mechanism and we show that they can be produced by variations in the (geometrically) thin disc accretion rate as well as by varying reprocessed fractions through changes in the location of the X-ray corona
Parameters of Physical Performance of Qualified Football Players in the Preparatory Period of Training
No full textThe purpose of the work: to determine the level of physical fitness of qualified football players in the preparatory period of the annual macrocycle based on test indicators for the formation of rational programs for their preparation for competitive activities.
Material & methods. Contingent: 25 qualified football players of MFC “Metalurg” (Zaporizhzhya): 15 athletes – application form «A» and 10 athletes – application form “B” of the second stage of the “Champion” group VBET UA 2022-2023 season of Professional Football League of Ukraine. Methods: Analysis and systematization of data from scientific and methodical literature and the electronic resource of global information network «Internet»; pedagogical observations; pedagogical testing: PWC170 (Physical Working Capacity); Harvard Step-Test; pedagogical experiment of controlling orientation; methods of mathematical statistics.
Results. During the educational and training meetings, the test indicators had statistically significant differences in the direction of decreasing values of special physical capacity, from retractable microcycle to percussive microcycle (p<0,05): аPWC170 – 1469,33 ± 50,11 and 1377,67 ± 49,11 (kg•m•min-1), rPWC170 – 20,87 ± 0,69 and 20,71 ± 0,71 (kgm•min-1•kg-1), aVO2 max – 4002,23 ± 115,23 and 3857,54 ± 117,34 (ml•min-1), rVO2 max – 61,57 ± 1,51 and 54,37 ± 1,67 (ml•min-1•kg-1), in accordance. Also, during the educational and training meetings, the test indicators had statistically significant differences in the direction of increment values of special physical capacity: from percussive microcycle to submersible microcycle (p<0,05): аPWC170 – 1377,67 ± 49,11 and 1494,34 ± 51,78 (kg•m•min-1), rPWC170 – 20,71 ± 0,71 and 21,37 ± 0,85 (kgm•min-1•kg-1), aVO2 max – 3857,54 ± 117,34 and 3997,09 ± 114,89 (ml•min-1), rVO2 max – 54,37 ± 1,67 and 63,67 ± 1,71 (ml•min-1•kg-1), in accordance.
Conclusion. The way to solve this problem is the proposed methodical approach, which allows, on the one hand, to comprehensively approach the solution of the issue of the complex orientation of the training process of qualified football players in the preparatory period of training, on the other hand, it provides for the differentiation of the team composition into typological groups of athletes, which allows to have a targeted influence on indicators of special physical capacity and technical and tactical potential of qualified football players
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