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$^\circ$.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$\times10^{-7}$ d yr$^{-1}$. 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 $V$ and $R$ 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 $q=0.518$ and the orbital inclination of $i=89.^{\circ}86$ 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