A short description of Dynamic Eclipse Mapping methodology is given. These tools are designed for mapping the surface patterns of non-radial oscillations on eclipsing binary components, using the ...effective surface sampling of the eclipses. I present two approaches to the problem, an image reconstruction (EM) and a direct model fitting (DF) method, review their capabilities and limitations, then report about the status of their application on real data, with emphasis on the encountered difficulties and caveats.
In this work we report the discovery and analysis of six new compact triply eclipsing triple star systems found with the TESS mission: TICs 37743815, 42565581, 54060695, 178010808, 242132789, and ...456194776. All of these exhibit distinct third body eclipses where the inner eclipsing binary (EB) occults the third (`tertiary') star, or vice versa. We utilized the TESS photometry, archival photometric data, and available archival spectral energy distribution curves (SED) to solve for the properties of all three stars, as well as many of the orbital elements. We describe in detail our SED fits, search of the archival data for the outer orbital period, and the final global photodynamical analyses. From these analyses we find that all six systems are coplanar to within \(0^\circ\) - \(5^\circ\), and are viewed nearly edge on (i.e., within a couple of degrees). The outer orbital periods and eccentricities of the six systems are {\(P_{\rm out}\) (days), \(e\)}: {68.7, 0.36}, {123, 0.16}, {60.7, 0.01}, {69.0, 0.29}, {41.5, 0.01}, {93.9, 0.29}, respectively, in the order the sources are listed above. The masses of all 12 EB stars were in the range of 0.7-1.8 M\(_\odot\) and were situated near the main sequence. By contrast, the masses and radii of the tertiary stars ranged from 1.5-2.3 M\(_\odot\) and 2.9-12 R\(_\odot\), respectively. We use this information to estimate the occurrence rate of compact flat triple systems.
In this work we report the discovery and analysis of three new triply eclipsing triple star systems found with the TESS mission during its observations of the northern skies: TICs 193993801, ...388459317, and 52041148. We utilized the TESS precision photometry of the binary eclipses and third-body eclipsing events, ground-based archival and follow-up photometric data, eclipse timing variations, archival spectral energy distributions, as well as theoretical evolution tracks in a joint photodynamical analysis to deduce the system masses and orbital parameters of both the inner and outer orbits. In one case (TIC 193993801) we also obtained radial velocity measurements of all three stars. This enabled us to `calibrate' our analysis approach with and without `truth' (i.e., RV) data. We find that the masses are good to 1-3% accuracy with RV data and 3-10% without the use of RV data. In all three systems we were able to find the outer orbital period before doing any detailed analysis by searching for a longer-term periodicity in the ASAS-SN archival photometry data -- just a few thousand ASAS-SN points enabled us to find the outer periods of 49.28 d, 89.86 d, and 177.0 d, respectively. From our full photodynamical analysis we find that all three systems are coplanar to within \(1^\circ - 3^\circ\). The outer eccentricities of the three systems are 0.003, 0.10, and 0.62, respectively (i.e., spanning a factor of 200). The masses of the three stars {Aa, Ab, and B} in the three systems are: {1.31, 1.19, 1.34}, {1.82, 1.73, 2.19}, and {1.62, 1.48, 2.74} M\(_\odot\), respectively.
The aim of the present study was to compare the apico-basal distribution of ion currents and the underlying ion channel proteins in canine and human ventricular myocardium.
Ion currents and action ...potentials were recorded in canine cardiomyocytes, isolated from both apical and basal regions of the heart, using whole-cell voltage clamp techniques. Density of channel proteins in canine and human ventricular myocardium was determined by Western blotting.
Action potential duration was shorter and the magnitude of phase-1 repolarization was significantly higher in apical than basal canine myocytes. No differences were observed in other parameters of the action potential or cell capacitance. Amplitude of the transient outward K(+) current (29.6+/-5.7 versus 16.5+/-4.4 pA/pF at +65 mV) and the slow component of the delayed rectifier K(+) current (5.61+/-0.43 versus 2.14+/-0.18 pA/pF at +50 mV) were significantly larger in apical than in basal myocytes. Densities of the inward rectifier K(+) current, rapid delayed rectifier K(+) current, and L-type Ca(2+) current were similar in myocytes of apical and basal origin. Apico-basal differences were found in the expression of only those channel proteins which are involved in mediation of the transient outward K(+) current and the slow delayed rectifier K(+) current: expression of Kv1.4, KChIP2, KvLQT1 and MinK was significantly higher in apical than in basal myocardium in both canine and human hearts.
The results suggest that marked apico-basal electrical inhomogeneity exists in the canine-and probably in the human-ventricular myocardium, which may result in increased dispersion, and therefore, cannot be ignored when interpreting ECG recordings, pathological alterations, or drug effects.
The Type Ia Supernova 2001V in NGC 3987 Vinkó, J.; Bíró, I. B.; Csák, B. ...
Astronomy and astrophysics (Berlin),
01/2003, Letnik:
397, Številka:
1
Journal Article
Recenzirano
Odprti dostop
CCD photometry is presented of the type Ia SN 2001V occurred in the edge-on spiral galaxy NGC 3987. The observations made through Johnson-Cousins BVRI filters were collected from Feb. 24 ($t = - 8$ ...days, with respect to B-maximum), up to May 5 ($t = +62$ days). The light curves are analyzed with the revised Multi-Colour Light Curve Shape (MLCS) method (CITE) by fitting template vectors to the observed light curves simultaneously. The reddening of SN 2001V is estimated to be $E(B-V)=0.05$ mag, while the galactic component is $E(B-V) = 0.02$ mag (Schlegel et al. CITE), suggesting that part of the reddening may be due to the ISM in the host galaxy. The Δ parameter in MLCS converged to -0.47 mag, indicating that this SN was overluminous relative to the majority of Type Ia SNe. The inferred distance to its host galaxy, NGC 3987, is $74.5 \pm 5$ Mpc, which is in good agreement with recently determined kinematic distances, based on radial velocity corrected for Virgo-infall and Hubble constant $H_0 = 65$ km s-1Mpc-1.
Results of a new light-curve analysis and period variation study of the eclipsing binary IM Aur are presented. Four solutions are given according to the different spectral types of the primary, ...available in the literature. Multicolour photometry and the period analysis both indicate a close (≈ $ 0\farcs1$) third physical member. If it is considered as a main-sequence star, then its spectral type is A2V–A8V, with a mass of $m_3\approx1.7{-}2.5~M_\odot$. The light-time effect is modelled by the authors' simultaneous secular and periodic terms fitting code. Clear evidence of a secular period change is also revealed. The detailed effects of the perturbations by a third member of a close binary system are extensively studied, using one of the authors' latest numerical integrator code. Although the amplitudes of the expected O-C changes are too small and also the data set is far undersampled for clear confirmation of the theoretical expectation of the third body-perturbed eclipsing binary O-C curve, some typical patterns are shown for their possible identification amongst the O-C curves of other closer systems (like Algol, λ Tau) in the near future.
Abstract
Aim
Various components of metabolic syndrome associate with cardiac intracellular calcium (
) mishandling, a precipitating factor in the development of heart failure. We aimed to provide a ...thorough description of early stage
‐cycling alterations in the fructose‐fed rat, an experimental model of the disorder, where insulin resistance, hypertension and dyslipidaemia act cooperatively on the heart.
Method
Rats were fed with fructose‐rich chow. After 6 weeks, echocardiography was performed, which was followed by measurements of myocardial
transients recorded by
I
ndo‐1 surface fluorometry in isolated perfused hearts. Sarcoplasmic reticulum (
SR
)
C
a
2+
‐
ATP
ase (
SERCA
2a) activity was assessed by administration of its inhibitor cyclopiazonic acid (
CPA
). Mathematical model analysis of
transients was used to estimate kinetic properties of
SR C
a
2+
transporters. Protein levels of key
C
a
2+
handling proteins were also measured.
Results
Echocardiography showed signs of cardiac hypertrophy, but
in vivo
and
ex vivo
haemodynamic performance of fructose‐fed rat hearts were unaltered. However, a decline in
C
a
2+
sequestration capacity (
and decay time of
transients) was observed. Model estimation showed decreased affinity for
C
a
2+
(higher
K
m
) and elevated
V
max
for
SERCA
2a. Diseased hearts were more vulnerable to
CPA
application. Fructose feeding caused elevation in
SERCA
2a and phosphorylated phospholamban (
PLB
) expression, while total
PLB
level remained unchanged.
Conclusion
In early stage, metabolic syndrome primarily disturbs
SERCA
2a function in the heart, but consequential haemodynamic dysfunction is prevented by upregulation of
SERCA
2a protein level and phosphorylation pathways regulating
PLB
. However, this compensated state is very vulnerable to a further decline in
SERCA
2a function.
Context. Despite the fact that VW Cephei is one of the well-studied contact binaries in the literature, there is no fully consistent model available that can explain every observed property of this ...system. Aims. Our motivation is to obtain new spectra along with photometric measurements, to analyze what kind of changes may have happened in the system in the past two decades, and to propose new ideas for explaining them. Methods. For the period analysis we determined 10 new times of minima from our light curves, and constructed a new O\(-\)C diagram of the system. Radial velocities of the components were determined using the cross-correlation technique. The light curves and radial velocities were modelled simultaneously with the PHOEBE code. All observed spectra were compared to synthetic spectra and equivalent widths of the H\(\alpha\) line were measured on their differences. Results. We have re-determined the physical parameters of the system according to our new light curve and spectral models. We confirm that the primary component is more active than the secondary, and there is a correlation between spottedness and the chromospheric activity. We propose that flip-flop phenomenon occurring on the primary component could be a possible explanation of the observed nature of the activity. To explain the period variation of VW Cep, we test two previously suggested scenarios: presence of a fourth body in the system, and the Applegate-mechanism caused by periodic magnetic activity. We conclude that although none of these mechanisms can be ruled out entirely, the available data suggest that mass transfer with a slowly decreasing rate gives the most likely explanation for the period variation of VW Cep.
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