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Search Results: 1 - 10 of 401502 matches for " Czerny M "
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Die endovaskul re Behandlung des thorakoabdominellen Aortenaneurysmas mit fenestrierten und verzweigten Stent-Grafts
Funovics M,Czerny M
Zeitschrift für Gef??medizin , 2012,
Abstract: Durch die Entwicklung fenestrierter und verzweigter Stent-Grafts kann das thorakoabdominelle Aortenaneurysma heute endovaskul r behandelt werden. Je nach dem Durchmesser der Aorta am Abgang der jeweiligen Viszeralarterie kann entweder eine Fenestrierung unmittelbar an das Ostium gelegt werden, oder, wenn die Arterie aus dem Aneurysma abgeht, ein kurzer Seitenast der Endoprothese oberhalb des Arterienostiums platziert werden. Durch sekund re Sondierung der Endoprothese und der jeweiligen Fenestrierung bzw. des jeweiligen Zweiges wird ein dünner Verbindungs-Stent- Graft zur jeweiligen Viszeralarterie gelegt. Der Zugang erfolgt über eine chirurgische Freilegung der Femoralarterie bzw. der A. brachialis. Die Methode weist Erfolgsraten von 95 98 % und hervorragende mittelfristige Ergebnisse auf. Die 30-Tages-Mortalit t (um 6 %) und die Rate spinaler Isch mien (um 5 %) an Patienten, die für die offene Operation ungeeignet eingestuft wurden, ist vergleichbar mit den Ergebnissen der weltweit besten Zentren für die offene thorakoabdominelle Aortenchirurgie.
Mass of black holes: The State of the Art
B. Czerny,M. Nikolajuk
Physics , 2009,
Abstract: In this small review we present the actual state the knowledge about weighting black holes. Black holes can be found in stellar binary systems in our Galaxy and in other nearby galaxies, in globular clusters, which we can see in our and nearby galaxies, and in centres of all well-developed galaxies. Range of values of their masses is wide and cover about ten orders of magnitude (not taking into account the hypothetic primordial black holes). Establishing the presence of black holes, and in particular the measurement of their mass is one on the key issues for many branches of astronomy, from stellar evolution to cosmology.
Cloud model of the mean quasar spectrum
B. Czerny,A. -M. Dumont
Physics , 1998,
Abstract: We assume a distribution of clouds optically thick for electron scattering (OTCM) which are moderately optically thin for absorption and we consider them as a model of the mean quasar spectrum of Laor et al. (1997). We show that the model is particularly sensitive to the value of the ionization parameter $\xi$ and that for $\xi \sim 500$ the model well reproduces the optical/UV/X-ray mean quasar spectrum, in agreement with the estimates of the ionization parameter based on the energy of the iron $K_{\alpha}$ line. We cannot definitively reject synchrotron emission as a source of primary radiation but we favor the model in which the hard X-ray emission is produced by Compton scattering of soft photons in a central hot medium surrounded by cool clouds. In such a model clouds are located typically at the distance of $\sim 12 R_{Schw}$, with the covering factor about 0.88 and the radius of hot plasma is $\sim 9 R_{Schw}$. The model explains optical/UV emission as predominantly due to the dark sides of the clouds and the soft X-ray emission as due to the reflection by the irradiated sides of the clouds. Therefore, atomic features are expected in these bands although they are hardly present in the observational data. The kinematical effects connected with the cloud motion affect those features but do not remove them. The level of the primary emission required to model the mean quasar spectrum is too low to reproduce the equivalent width of the iron K$_{\alpha}$ line correctly but more detailed computations may resolve this problem.
MIDCAB Operationen in Wien - die ersten Erfahrungen
Czerny M,Grimm M,Wolner E
Journal für Kardiologie , 1999,
Abstract: Die sogenannte MIDCAB (minimal invasive direct coronary artery bypass) Operation wurde als chirurgische Therapie der koronaren Eingef erkrankung in letzter Zeit kontroversiell diskutiert. Ihr klinischer Stellenwert ist weiterhin unklar. Im Zeitraum von April 1996 bis Mai 1998 wurde die MIDCAB-Operation an 57 Patienten an der Abteilung für Herz-Thorax Chirurgie, Universit t Wien durchgeführt. Zielgef e für eine chirurgische Revaskularisierung waren die LAD (n = 52) und die RCA (n = 5). Als arterieller Graft dienten die linke Art. mammaria interna (LAD-Bypass) bzw. die Art. gastroepiploica dextra (RCA-Bypass). Als Zug nge wurden limitierte Schnittführungen gew hlt, in 91% der F lle die anterolaterale Thorakotomie und in 9% der subxyphoidale Zugang, die Anastomosierungen erfolgten am schlagenden Herzen ohne Herzlungenmaschine. In 52 F llen wurde die LIMA (Left internal mammary artery) mit der LAD anastomosiert. Bei 3 von 52 Patienten mu te wegen einer intramyokardialen LAD zu einer konventionellen Operation gewechselt werden, in 4 F llen war eine Revision notwendig. In allen F llen gab es keinen Todesfall und keinen perioperativen Infarkt. Bei 36 Patienten wurde eine postoperative Kontrollangiographie durchgeführt, es ergab sich eine prim re Offenheitsrate von 96%. In 5 F llen wurde eine Anastomose zwischen GEA und RCA hergestellt. Es gab keine Konversion, keinen Todesfall und keinen Myokardinfarkt. Drei dieser Patienten wurden postoperativ nachangiographiert, die Byp sse waren gut durchg ngig. Zum derzeitigen Zeitpunkt sind alle 57 Patienten klinisch symptomfrei. Nach überwindung von anf nglichen technischen Schwierigkeiten sind die Ergebnisse mit der MIDCAB-Operation sehr gut. Als potentielles Patientenkollektiv für die Zukunft scheinen sich vor allem Patienten nach multiplen kardiologischen Interventionen an der LAD bzw. der RCA anzubieten.
Akute thorakale Aortendissektion - Altbekanntes und Neues
Sodeck GH,Czerny M,Domanovits H
Zeitschrift für Gef??medizin , 2008,
Abstract: Der frühzeitige klinische Verdacht ist der Schlüsselfaktor für die Diagnose der akuten thorakalen Aortendissektion, einer seltenen, aber lebensbedrohlichen Erkrankung. Die Best tigung des klinischen Verdachts die Diagnose erfolgt mit geeigneter Bildgebung: Computertomographie/Echokardiographie/MRT. Ein negativer D-Dimer-Test kann das Vorhandensein dieser akuten Aortenpathologiemit hoher Sicherheit ausschlie en.
Spectral properties of the Narrow-Line Seyfert 1 Quasar PG1211+143
Agnieszka Janiuk,Bozena Czerny,Grzegorz M. Madejski
Physics , 2001,
Abstract: We propose a theoretical model to explain the spectrum of the quasar PG1211+143 emitted in the Optical/X-ray bands. In particular, we suggest that the inner accretion disk may develop a warm, optically thick skin, which produces a profound emission feature observed in the soft X-ray band. This is well modelled with the Comptonized black body emission. The same warm, mildly ionized medium may also be responsible for the hard X-ray reflection and the presence of the iron $K_{\alpha}$ line. However, in our model it still remains an open question, whether the seed photons for Comptonization come from the cold accretion disc or from the hotter plasma. High resolution spectroscopy available through the Chandra and XMM data may provide now an independent test of the physical conditions in the Comptonizing and reflecting warm skin.
The Nature of the Emission Components in the Quasar/NLS1 PG1211+143
A. Janiuk,B. Czerny,G. M. Madejski
Physics , 2001, DOI: 10.1086/321617
Abstract: We present the study of the emission properties of the quasar PG1211+143, which belongs to the class of Narrow Line Seyfert 1 galaxies. On the basis of observational data analyzed by us and collected from the literature, we study the temporal and spectral variability of the source in the optical/UV/X-ray bands and we propose a model that explains the spectrum emitted in this broad energy range. In this model, the intrinsic emission originating in the warm skin of the accretion disk is responsible for the spectral component that is dominant in the softest X-ray range. The shape of reflected spectrum as well as Fe K line detected in hard X-rays require the reflecting medium to be mildly ionized (xi~500). We identify this reflector with the warm skin of the disk and we show that the heating of the skin is consistent with the classical alpha P_{tot} prescription, while alpha P_{gas} option is at least two orders of magnitude too low to provide the required heating. We find that the mass of the central black hole is relatively small (M_BH~10^7- 10^8 Msun, which is consistent with the Broad Line Region mapping results and characteristic for NLS1 class.
Variability of accretion flow in the core of the Seyfert galaxy NGC 4151
B. Czerny,V. T. Doroshenko,M. Nikolajuk,A. Schwarzenberg-Czerny,Z. Loska,G. Madejski
Physics , 2001, DOI: 10.1046/j.1365-8711.2003.06623.x
Abstract: We analyze observations of the Seyfert galaxy NGC 4151 covering 90 years in the optical band and 27 years in the 2-10 keV X-ray band. We compute the Normalized Power Spectrum Density (NPSD), the Structure Function (SF) and the Autocorrelation Function (ACF) for these data. The results show that the optical and X-ray variability properties are significantly different. X-ray variations are predominantly in the timescale range of 5 - 1000 days. The optical variations have also a short timescale component which may be related to X-ray variability but the dominant effect is the long timescale variability, with timescales longer than $\sim$ 10 years. We compare our results with observations of NGC 5548 and Cyg X-1. We conclude that the long timescale variability may be caused by radiation pressure instability in the accretion disk, although the observed timescale in NGC 4151 is by a factor of few longer than expected. X-ray variability of this source is very similar to what is observed in Cyg X-1 but scaled with the mass of the black hole, which suggests that the radiation pressure instability does not affect considerably the X-ray production.
Towards equation of state of dark energy from quasar monitoring: Reverberation strategy
B. Czerny,K. Hryniewicz,I. Maity,A. Schwarzenberg-Czerny,P. T. Zycki,M. Bilicki
Physics , 2012, DOI: 10.1051/0004-6361/201220832
Abstract: High redshift quasars can be used to deduce the distribution of dark energy in the Universe, as a complementary tool to SN Ia. The method is based on determination of the size of the Broad Line Region from the emission line delay, determination of the absolute monochromatic luminosity either from the observed statistical relation or from a model of the formation of the Broad Line Region, and determination of the observed monochromatic flux from photometry. This allows to obtain the luminosity distance to a quasar independently from its redshift. The accuracy of the measurements is however, a key issue. We model the expected accuracy of the measurements by creating artificial quasar monochromatic lightcurves and responses from the Broad Line Region under various assumptions about the variability of a quasar, Broad Line Region extension, distribution of the measurements in time, accuracy of the measurements and the intrinsic line variability. We show that the five year monitoring based on Mg II line should give the accuracy of 0.06 - 0.32 magnitude in the distance modulus which allows to put interesting constraints on the cosmological models. Monitoring of higher redshift quasars based on CIV lines is problematic due to much higher level of the intrinsic variability of CIV in comparison with Mg II.
Indikationen zur Herztransplantation
Zimpfer D,Czerny M,Grimm M,Hülsmann M
Journal für Kardiologie , 2004,
Abstract:
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