89 research outputs found
Cardiac papillary fibroelastomas: A 10-year single-center surgical experience and long-term echocardiographic follow-up study
Aims. Limited contemporary data are available on the clinical and echocardiographic outcomes after surgery for cardiac papillary fibroelastoma (CPF). The aim of this study was to review the clinical manifestations, pathological characteristics, surgical management, and prognoses of patients with histologically verified CPF, who underwent surgery at our cardiac surgery center from 2008 to 2018.
Methods and Results. Twelve patients of median age 62 years (28 to 77 years) were treated. Embolic stroke or transient ischemic attack (five patients, 42%) were the only CPF clinical manifestations. Eleven (92%) tumors were localized on the valves, with the aortic valve being the most common tumor site (seven patients; 58%). Multiple factor analysis revealed no independent predictor of CPF-related embolization. Simple shave tumor excision was sufficient in most patients (10 patients, 83%). No operative or tumor-related late mortality during the median follow-up period of 4.7 years (1.1 to 10.2 years) was recorded. Asymptomatic metachronous valve tumor recurrence (in a location different from that of the original tumor) was revealed in two patients (17%) by transesophageal echocardiography (TEE), not detected by transthoracic echocardiography (TTE). One of these two patients underwent repeated surgery for CPF but later suffered a recurrent embolic stroke, due to another tumor recurrence.
Conclusion. CPF can be safely and effectively treated surgically. TEE is superior to the TTE option in CPF post-operative recurrence detection. There is a clear need for a prospective study to determine criteria for embolization risk stratification and optimum management in patients with CPF.Web of Science1641918
The First Comprehensive Photometric Study of the Algol-type System CL Aurigae
We present the first extensive photometric results of CL Aur from our BVRI
CCD photometry made on 22 nights from 2003 November through 2005 February.
Fifteen new timings of minimum light were obtained. During the past 104 years,
the orbital period has varied due to a periodic oscillation superposed on a
continuous period increase. The period and semi-amplitude of the oscillation
are about 21.6 yrs and 0.0133 d, respectively. This detail is interpreted as a
light-travel-time effect due to a low-luminosity K-type star gravitationally
bound to the CL Aur close system. Our photometric study indicates that CL Aur
is a relatively short-period Algol-type binary with values of q=0.602 and
i=88.2. Mass transfer from the secondary to the primary eclipsing
component is at least partly responsible for the observed secular period change
with a rate of dP/dt = +1.4 d yr. A cool spot model has
been calculated but we think that an alternative hot-spot model resulting from
a gas stream impact on the hot star is more reasonable despite two difficulties
with the explanation. Absolute dimensions of the eclipsing system are deduced
and its present state is compared with tracks for single star and conservative
close binary evolution. Finally, we examine the possible reconciliation of two
different calculations of the luminosity of the hot spot and a
re-interpretation of the secular term of the period variability.Comment: 26 pages, including 5 figures and 9 tables, accepted for publication
in A
Exoplanet Transit Database. Reduction and processing of the photometric data of exoplanet transits
We demonstrate the newly developed resource for exoplanet researchers - The
Exoplanet Transit Database. This database is designed to be a web application
and it is open for any exoplanet observer. It came on-line in September 2008.
The ETD consists of three individual sections. One serves for predictions of
the transits, the second one for processing and uploading new data from the
observers. We use a simple analytical model of the transit to calculate the
central time of transit, its duration and the depth of the transit. These
values are then plotted into the observed - computed diagrams (O-C), that
represent the last part of the application.Comment: Accepted to NewAstronom
The quest for companions to post-common envelope binaries: III. A reexamination of HW Virginis
We report new mid-eclipse times of the short-period sdB/dM binary HW Vir,
which differ substantially from the times predicted by a previous model. The
proposed orbits of the two planets in that model are found to be unstable. We
present a new secularly stable solution, which involves two companions orbiting
HW VIr with periods of 12.7 yr and 55 +/-15 yr. For orbits coplanar with the
binary, the inner companion is a giant planet with mass M_3 sin i_3 = 14 M_Jup
and the outer one a brown dwarf or low-mass star with a mass of M_4 sin i_4 =
30-120 M_Jup. Using the mercury6 code, we find that such a system would be
stable over more than 10^7 yr, in spite of the sizeable interaction. Our model
fits the observed eclipse-time variations by the light-travel time effect
alone, without invoking any additional process, thereby providing support for
the planetary hypothesis of the eclipse-time variations in close binaries. The
signature of non-Keplerian orbits may be visible in the data.Comment: accepted by A&
Automatický měřící systém pro měření izolačních parametrů a odporů cívek elektromagnetů
Bakalářská práce se zabývá stavbou automatizovaného pracoviště pro měření kvality
elektromagnetických cívek. Naměřené údaje se ukládají a statisticky vyhodnocují pro optimalizaci
výrobního procesu a oceňování pracovníků. Měřící proces musí být plně automatizován z důvodu
eliminace chyb způsobených lidským faktorem a zvýšení bezpečnosti pracovníka. Pro měření jsou
požadovány odolnostní testy na vysoké napětí střídavého i stejnosměrného průběhu. Test na kvalitu
spoje zemnícího kolíku s kovovým pláštěm cívky. A velmi přesné měření odporu vinutí cívek. Mým
úkolem bylo vytvořit uživatelské a řídící rozhraní pro celé pracoviště
Client-server search engine for optimal public transport routes
Bakalářská práce se zabývá návrhem programu s architekturou klient-server pro hledání cesty v sítích městské hromadné dopravy. V rámci teoretického úvodu je popsán problém obchodního cestujícího a jsou zmíněny metody jeho řešení. Následuje teoretický návrh samotného programu. Další kapitola se věnuje konkrétně vybraným technologiím pro realizaci práce. Poslední pak už pojednává o samotné realizaci práce. Dosažené výsledky jsou pak hodnoceny v závěru.This bachelor thesis deals with the design and implementation of a client-server based program for finding the optimal path in public transport networks. Theoretical basics describe the Traveling salesman problem and mention some methods for finding its solution. This chapter is followed by a theoretical design of the application itself. Next chapter describes chosen technologies to be used. The last chapter describes the realization of the application itself. Reached goals are described in the conclusion.
Použití kombinace chirurgických a endovaskulárních technik v léčbě rozsáhlých onemocnění hrudní aorty
Lékařská fakulta v Hradci Králov
Spectroscopic and Photometric Study of the Contact Binary BO CVn
We present the results of the study of the contact binary system BO CVn. We
have obtained physical parameters of the components based on combined analysis
of new, multi-color light curves and spectroscopic mass ratio. This is the
first time the latter has been determined for this object. We derived the
contact configuration for the system with a very high filling factor of about
88 percent. We were able to reproduce the observed light curve, namely the flat
bottom of the secondary minimum, only if a third light has been added into the
list of free parameters. The resulting third light contribution is significant,
about 20-24 percent, while the absolute parameters of components are: M1=1.16,
M2=0.39, R1=1.62 and R2=1.00 (in solar units). The O-C diagram shows an upward
parabola which, under the conservative mass transfer assumption, would
correspond to a mass transfer rate of dM/dt = 6.3 \times 10-8M\odot/yr, matter
being transferred from the less massive component to the more massive one. No
cyclic, short-period variations have been found in the O-C diagram (but
longer-term variations remain a possibility)Comment: 16 pages, 5 figures, 5 tables, accepted for publication by New
Astronom
First photometric study of the eclipsing binary PS Persei
The CCD photometric observations of the eclipsing binary PS Persei (PS Per)
were obtained on two consecutive days in 2009. The 2003 version Wilson-Devinney
code was used to analyze the first complete light curves in and bands.
It is found that PS Per is a short-period Algol-type binary with the less
massive component accurately filling its inner critical Roche lobe. The mass
ratio of and the orbital inclination of are
obtained. On the other hand, based on all available times of primary light
minimum including two new ones, the orbital period has been improved.Comment: 7 pages, 4 figure
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