Symbiotic stars as possible progenitors of SNe Ia: binary parameters and overall outlook

Symbiotic stars are interacting binaries in which the first-formed white dwarf accretes and burns material from a red giant companion. This paper aims at presenting physical characteristics of these objects and discussing their possible link with progenitors of type Ia supernovae.Comment: 4 pages. Invited rewiev at "Binary Paths to Type Ia Supernovae", IAU Symposium No. 281, R. Di Stefano & M. Orio, eds., Cambridge University Pres

Symbiotic stars: Observations confront theory

In this paper, I present and discuss some recent observational results which may have important implications for our understanding of late phases of binary evolution.Comment: 8 pages, 3 figures; to appear in the proceedings of the Asiago Workshop on Symbiotic Stars, A. Siviero and U. Munari eds., Baltic Astronomy special issu

Mm/submm observations of symbiotic binary stars: implications for the mass loss and mass exchange

We discuss mm/submm spectra of a sample of symbiotic binary systems, and compare them with popular models proposed to account for their radio emission. We find that radio emission from quiescent S-type systems originates from a conical region of the red giant wind ionized by the hot companion (the STB model), whereas more complicated models involving winds from both components and their interaction are required to account for radio emission of active systems. We also find that the giant mass-loss rates derived from our observations are systematically higher than those for single cool giants. This result is in agreement with conclusions derived from IRAS observations and with requirements of models for the hot component.Comment: 7 pages, 8 figures. Paper presented at COSPAR 2000 "New results in FIR and Submm Astronomy", to be published in Advances in Space Researc

The secondary minimum in YY Her: Evidence for a tidally distorted giant

We present and analyze quiescent UBVRI light curves of the classical symbiotic binary YY Her. We show that the secondary minimum, which is clearly visible only in the quiescent VRI light curves, is due to ellipsoidal variability of the red giant component. Our simple light curve analysis, by fitting of the Fourier cosine series, resulted in a self-consistent phenomenological model of YY Her, in which the periodic changes can be described by a combination of the ellipsoidal changes and a sinusoidal changes of the nebular continuum and line emission.Comment: 5 pages, 2 figures, to appear in Astronomy & Astrophysic

First spatial resolution of the stellar components of the interacting binary CH Cygni

We report the first resolved bispectrum speckle interferometry of the symbiotic binary CH Cyg. The measured component separation, $\rho=42 \pm 2$ mas, is consistent with the one derived from the known spectroscopic orbit and distance. In particular, our result implies a total mass of the binary of M_{\rm t}=M_{\rm g}+M_{\rm wd}=3.7^{+3.5}_{-1.7} \rm M_{\sun}, which is in good agreement with the value M_{\rm t}=2.7^{+1.2}_{-0.6} \rm M_{\sun} derived from the spectroscopic orbit solution for the red giant and evolutionary contraints. We also show that the radio jets and the bipolar outflow are not orthogonal to the orbital plane of the binary system.Comment: 5 pages, 4 figures, submitted to MNRA

Factors influencing use of assistive technology in post-stroke patients – preliminary findings

Background. Assistive technology (AT) is regarded as one of the most important factors influencing functional recovery and independence in patients after stroke. There is still a need for research on predictors and early identification of AT requirements in order to shape and maximize its positive influence on the recovery process. Objective. To identify and evaluate relationship between selected factors (age, sex, time after cerebrovascular accident) and AT use. Results. Among 140 patients involved in the study, the use of AT was as follows: the most common AT equipment were wheelchairs (used by 40.81% of patients), canes (15.71%) and husks (15%). Up to 5 % patients used more than one AT device. Sex, age, time after cerebrovascular accident, and post-stroke complications were important factors influencing AT use in stroke-survivors. Conclusions. Study outcomes confirm important clinical information extending existing studies, especially co-occurrence of AT devices use.Wprowadzenie. Technologia wspomagająca jest uważana za jeden z najważniejszych czynników wpływa-jących na funkcjonalny powrót do zdrowia i samodzielność pacjentów po udarze. Wciąż jednak potrzebne są badania w zakresie czynników predykcyjnych i wczesnej identyfi-kacji potrzeb w zakresie technologii wspomagającej, aby kształtować i maksymalizować pozytywny wpływ tej grupy rozwiązań technicznych na proces powrotu do zdrowia. Cel . Identyfikacja i ocena związków pomiędzy wybranymi czynnikami (wiekiem, płcią, czasem po udarze) a wykorzystaniem technologii wspomagającej. Wyniki. Pośród 140 pacjentów biorących udział w badaniu najczęściej spotykanymi przedmiotem należącymi do technologii wspomagającej były wózki dla osób niepełnosprawnych (używane przez 40,81% badanych), laski (15,71%) i łuski (15%). Do 5% pacjentów wykorzystywało więcej niż jeden przedmiot należący do technologii wspomagających. Płeć, wiek, czas od udaru oraz zmiany wtórne po udarze stanowiły istotne czynniki wpływające na wykorzystanie technologii wspomagającej u pacjentów po udarze.   Wnioski. Badanie potwierdza ważne klinicznie dane rozszerzając dotychczasowe badania, szczególnie w obszarze jednoczesnego wykorzystywania różnych przedmiotów należących do technologii wspomagającej