Modifying the Standard Disk Model for the Ultraviolet Spectral Analysis of Disk-dominated Cataclysmic Variables. I. The Novalikes MV Lyrae, BZ Camelopardalis, and V592 Cassiopeiae.

The standard disk is often inadequate to model disk-dominated cataclysmic variables (CVs) and generates a spectrum that is bluer than the observed UV spectra. X-ray observations of these systems reveal an optically thin boundary layer (BL) expected to appear as an inner hole in the disk. Consequently, we truncate the inner disk. However, instead of removing the inner disk, we impose the no-shear boundary condition at the truncation radius, thereby lowering the disk temperature and generating a spectrum that better fits the UV data. With our modified disk, we analyze the archival UV spectra of three novalikes that cannot be fitted with standard disks. For the VY Scl systems MV Lyr and BZ Cam, we fit a hot inflated white dwarf (WD) with a cold modified disk ( [Formula: see text] ~ a few 10-9M⊙ yr-1). For V592 Cas, the slightly modified disk ( [Formula: see text] ~ 6 × 10-9M⊙ yr-1) completely dominates the UV. These results are consistent with Swift X-ray observations of these systems, revealing BLs merged with ADAF-like flows and/or hot coronae, where the advection of energy is likely launching an outflow and heating the WD, thereby explaining the high WD temperature in VY Scl systems. This is further supported by the fact that the X-ray hardness ratio increases with the shallowness of the UV slope in a small CV sample we examine. Furthermore, for 105 disk-dominated systems, the International Ultraviolet Explorer spectra UV slope decreases in the same order as the ratio of the X-ray flux to optical/UV flux: from SU UMa's, to U Gem's, Z Cam's, UX UMa's, and VY Scl's.

FUSE Spectroscopy of the Accreting Hot Components in Symbiotic Variables.

We have conducted a spectroscopic analysis of the far ultraviolet archival spectra of four symbiotic variables, EG And, AE Ara, CQ Dra and RW Hya. RW Hya and EG And have never had a recorded outburst while CQ Dra and AE Ara have outburst histories. We analyze these systems while they are in quiescence in order to help reveal the physical properties of their hot components via comparisons of the observations with optically thick accretion disk models and NLTE model white dwarf photospheres. We have extended the wavelength coverage down to the Lyman Limit with FUSE spectra. We find that the hot component in RW Hya is a low mass white dwarf with a surface temperature of 160,000K. We re-examine whether or not the symbiotic system CQ Dra is a triple system with a red giant transferring matter to a hot component made up of a cataclysmic variable in which the white dwarf has a surface temperature as low as ∼20,000K. The very small size of the hot component contributing to the shortest wavelengths of the FUSE spectrum of CQ Dra agrees with an optically thick and geometrically thin (∼4% of the WD surface) hot (∼ 120, 000K) boundary layer. Our analysis of EG And reveals that its hot component is a hot, bare, low mass white dwarf with a surface temperature of 80-95,000K, with a surface gravity log(g) = 7.5. For AE Ara, we also find that a low gravity (log(g) ∼ 6) hot (T ∼ 130, 000K) WD accounts for the hot component.

Far Ultraviolet Spectroscopy of Old Novae. II. RR Pic, V533 Her, and DI Lac.

The old novae V533 Her (Nova Her 1963), DI Lac (Nova Lac 1910), and RR Pic (Nova Pic 1891) are in (or near) their quiescent stage, following their nova explosions, and continue to accrete at a high rate in the aftermath of their explosions. They exhibit continua that are steeply rising into the FUV, as well as absorption lines and emission lines of uncertain origin. All three have Far Ultraviolet Spectroscopic Explorer (FUSE) spectra that offer not only higher spectral resolution but also wavelength coverage extending down to the Lyman Limit. For DI Lac, we have matched these FUSE spectra with existing archival International Ultraviolet Explorer spectral coverage to broaden the FUV wavelength coverage. We adopted the newly determined interstellar reddening corrections of Selvelli & Gilmozzi. The dereddened FUV spectra have been modeled with our grids of optically thick accretion disks and hot, NLTE white dwarf (WD) photospheres. The results of our modeling analysis indicate that the hot components in RR Pic and V533 Her are likely to be accretion disks with mass accretion rates of 10-8M⊙ yr-1 and 10-9M⊙ yr-1 respectively. However, the disk cannot produce the observed absorption lines. For the WD to be the source of the absorption lines in these two systems, it must be very hot, with a radius several times its expected size (because the WD in these systems is massive, it has a smaller radius). For DI Lac, we find the best fit to be a disk with M = 10-10M⊙ yr-1 with a 30,000 K WD.

Hubble COS Spectroscopy of the Dwarf Nova CW Mon: The White Dwarf in Quiescence?

We present a synthetic spectral analysis of the HST COS spectrum of the U Geminorum-type dwarf nova CW Mon, taken during quiescence as part of our COS survey of accreting white dwarfs in Cataclysmic Variables. We use synthetic photosphere and optically thick accretion disk spectra to model the COS spectrum as well as archival IUE spectra obtained decades ago when the system was in an even deeper quiescent state. Assuming a reddening of E(B-V)=0.06, an inclination of 60° (CW Mon has eclipses of the accretion disk, and a white dwarf mass of 0.8M⊙, our results indicate the presence of a 22-27,000 K white dwarf and a low mass accretion rate [Formula: see text], for a derived distance o ~200 to ~300 pc.

Far Ultraviolet Spectroscopy of Old Novae I. V603 Aquila.

We present the results of a synthetic spectral analysis of the far ultraviolet archival IUE, HST and FUSE observations of the fast old nova V603 Aql, obtained some 90 years after its 1918 nova outburst. Our analysis utilizes the new Hubble FGS parallax distance for this nearly face-on old nova, a high white dwarf mass and a low reddening. Our analysis includes non-truncated optically thick accretion disks since V603 Aql is neither a polar nor an intermediate polar. Our synthetic spectral modeling of the FUSE and HST spectra analyzed separately indicate a mass transfer rate [Formula: see text] for the FUSE and HST spectra respectively, assuming a WD mass of 1.2M⊙. The mass accretion rate also depends on the assumed WD mass, and increases by a factor of two for a WD mass of 0.8M⊙. Combining the FUSE and HST spectra together lead to the same results. Potential implications are discussed.

White Dwarfs in Cataclysmic Variables: An Update.

In this review, we summarize what is currently known about the surface temperatures of accreting white dwarfs in non-magnetic and magnetic cataclysmic variables (CVs) based upon synthetic spectral analyses of far ultraviolet data. We focus only on white dwarf surface temperatures, since in the area of chemical abundances, rotation rates, WD masses and accretion rates, relatively little has changed since our last review, pending the results of a large HST GO program involving 48 CVs of different CV types. The surface temperature of the white dwarf in SS Cygni is re-examined in the light of its revised distance. We also discuss new HST spectra of the recurrent nova T Pyxidis as it transitioned into quiescence following its April 2011 nova outburst.

HUBBLE SPACE TELESCOPE FAR ULTRAVIOLET SPECTROSCOPY OF THE RECURRENT NOVA T PYXIDIS.

With six recorded nova outbursts, the prototypical recurrent nova T Pyxidis (T Pyx) is the ideal cataclysmic variable system to assess the net change of the white dwarf mass within a nova cycle. Recent estimates of the mass ejected in the 2011 outburst ranged from a few ~10-5M⊙ to 3.3 × 10-4M⊙, and assuming a mass accretion rate of 10-8-10-7M⊙ yr-1 for 44 yr, it has been concluded that the white dwarf in T Pyx is actually losing mass. Using NLTE disk modeling spectra to fit our recently obtained Hubble Space Telescope COS and STIS spectra, we find a mass accretion rate of up to two orders of magnitude larger than previously estimated. Our larger mass accretion rate is due mainly to the newly derived distance of T Pyx (4.8 kpc, larger than the previous 3.5 kpc estimate), our derived reddening of E(B - V) = 0.35 (based on combined IUE and GALEX spectra), and NLTE disk modeling (compared to blackbody and raw flux estimates in earlier works). We find that for most values of the reddening (0.25 ≤ E(B-V) ≤ 0.50) and white dwarf mass (0.70 M⊙ ≤ Mwd ≤ 1.35 M⊙) the accreted mass is larger than the ejected mass. Only for a low reddening (~0.25 and smaller) combined with a large white dwarf mass (0.9 M⊙ and larger) is the ejected mass larger than the accreted one. However, the best results are obtained for a larger value of reddening.

Athlete's heart or hypertrophic cardiomyopathy: usefulness of N-terminal pro-brain natriuretic peptide.

BACKGROUND: Distinguishing physiological hypertrophy from hypertrophic cardiomyopathy in athletes remains difficult, but vital in view of the risk of sudden death under effort. NT-proBNP was previously reported to be usually normal in healthy athletes, but often elevated in case of hypertrophic cardiomyopathy. OBJECTIVES: To assess the interest of NT-proBNP in differential diagnosis of left ventricular hypertrophy in athletes. METHODS: NT-proBNP levels were measured at rest and after effort in trained athletes referred for suspectedly abnormal (>or=13 mm) left ventricular hypertrophy. RESULTS: 17 patients were included, 10 of whom were diagnosed with hypertrophic cardiomyopathy (group I) while the other 7 presented typical signs of athlete's heart (group II). NT-proBNP levels did not significantly differ between groups, whether at rest or after effort. NT-proBNP levels were, however, significantly elevated in 3 subjects in group I, while being consistently normal in group II. CONCLUSIONS: In active athletes presenting with ambiguous left ventricular hypertrophy, abnormal NT-proBNP levels indicate hypertrophic cardiomyopathy, whereas normal values are inconclusive.

Cardiovascular disease in patients with spondyloarthropathies.

Spondyloarthropathies are associated with a greater cardiovascular risk than expected based on the cardiac lesions known to occur in these diseases. The prevalence of several conventional risk factors is high in spondyloarthropathy patients, and chronic inflammation also contributes to premature plaque formation. In addition, susceptibility genes for spondyloarthropathies may be associated with an increased risk of cardiovascular disease. Finally, several drugs used to treat spondyloarthropathies may contribute to the occurrence of cardiovascular events. A careful evaluation of the cardiovascular risk profile is a key component of the management of patients with spondyloarthropathies.

Significance of serum troponin I elevation in patients with acute aortic dissection of the ascending aorta.

OBJECTIVE: This study evaluated the prevalence of increased cardiac troponin I (cTnI) in patients with acute aortic dissection of the ascending aorta (type A). METHODS AND RESULTS: In 119 consecutive patients with type A acute aortic dissection, serum cardiac troponin I was measured along with clinical, haemodynamic, electrocardiographic and echocardiographic variables obtained on admission. Cardiac troponin I was positive in 28 patients (23.5%; mean +/- SD: 6.1 +/- 14.7 ng/ml) and above the myocardial infarction threshold (1.5 ng/ml) in 12 (10%). Catecholamine infusion (17.9% vs. 4.4%; p = 0.03) and higher value of creatinine (35.7% vs. 15.4%; p = 0.03) were more frequent in patients with elevated troponin. Total mortality was 29.7% (n = 35) and surgical mortality was 16.8% (n = 17). An increased troponin was discriminatory with respect to mortality (OR: 4.1 (1.6-9.9); p = 0.002) in univariate analysis. However, this association was lost when other markers of death (age, stroke, ST-segment elevation, tamponade, catecholamine infusion, renal failure) were added in a multivariate model (OR: 2.2 (0.7-7.4); p = 0.19) indicating that the myocardial loss associated with troponin increase is not in itself a factor of mortality. CONCLUSIONS: Cardiac troponin I elevation is frequent in patients with type A aortic dissection. It might reflect a higher haemodynamic stress but does not necessarily reflect a negative prognosis.

[Recurrent septicaemia following incomplete removal of pacemaker leads]. / Septicémie récidivante après extraction incomplète de sondes de stimulateur cardiaque.

INTRODUCTION: Septicaemia on endocardial pacemaker leads is very rare but the presentation is insidious and the prognosis very bad if all the implanted materiel is not completely removed. OBSERVATION: A 55 year-old woman presented three episodes of Staphylococcus epidermidis septicaemia in three years, after incomplete removal of the pacing system. Permanent cure was finally obtained after complete removal of the pacemaker material. COMMENT: Emphasis must be placed on the difficulty in diagnosing and treating such affections, their severity and also the interest of a certain number of prophylactic measures.