ST/STIS Spectroscopy of the White Dwarfs in the Short-Period Dwarf Novae LL And and EF Peg

We present new HST/STIS observations of the short-period dwarf novae LL And and EF Peg during deep quiescence. We fit stellar models to the UV spectra and use optical and IR observations to determine the physical parameters of the whitedwarfs in the systems, the distances to the binaries, and the properties of thesecondary stars. Both white dwarfs are relatively cool, having T_{eff} near 15000K, and consistent with a mass of 0.6 M-sun. The white dwarf in LL And appears to be of solar abundance or slightly lower while that in EF Peg is near 0.1-0.3 solar. LL And is found to be 760 pc away while EF Peg is closer at 380 pc. EF Peg appears to have an ~M5V secondary star, consistent with that expected for its orbital period, while the secondary object in LL And remains a mystery.Comment: Accepted in Ap

HST Spectra of GW Librae: A Hot Pulsating White Dwarf in a Cataclysmic Variable

We have obtained Hubble Space Telescope UV spectra of the white dwarf in GW Lib, the only known non-radially pulsating white dwarf in a cataclysmic variable, and the first known DAZQ variable. The UV light curve reveals large amplitude (10%) pulsationsin the UV with the same periods (646, 376 and 237 s) as those seen at optical wavelengths, but the mean spectrum fits with an average white dwarf temperature (14,700K for a 0.6M_{odot} white dwarf) that is too hot to be in the normal instability strip for ZZ Ceti stars. A better fit is achieved with a dual temperature model (with 63% of the white dwarf surface at a temperature of 13300K and 37% at 17100K), and a higher mass (0.8M_{odot}) white dwarf with 0.1 solar metal abundance. Since the blue edge of the instability strip moves to higher temperature with increasing mass, the lower temperature of this model is within the instability strip. However, the presence of accretion likely causes abundance and atmospheric temperature differences in GW Lib compared to all known single white dwarf pulsators, and the current models that have been capable of explaining ZZ Ceti stars may not apply.Comment: 13 pages, 4 figure

GALEX and Optical Light Curves of EF Eridanus During a Low State: the Puzzling Source of UV Light

Low state optical photometry of EF Eri during an extended low accretion state combined with GALEX near and far UV time-resolved photometry reveals a source of UV flux that is much larger than the underlying 9500K white dwarf, and that is highly modulated on the orbital period. The near UV and optical light curves can be modeled with a 20,000K spot but no spot model can explain both the large amplitude FUV variations and the SED. The limitations of limb darkening, cyclotron and magnetic white dwarf models in explaining the observations are discussed.Comment: 10 pages, 4 figures to be published in ApJ Letter

Keck IR Spectroscopy of WZ Sge: Detection of Molecular Emission from the Accretion Disk

Time-resolved IR spectroscopy of WZ Sge was obtained using NIRSPEC on Keck II. We detect CO and H$_{\rm 2}$ emission from the accretion disk placing WZ Sge into a rarefied class of astronomical objects including YSOs and high luminosity early-type stars. During the eclipse phase, the molecular emission greatly weakens but no firm evidence for the secondary star is seen allowing new limits on its luminosity to be determined. The detection of molecular emission provides physical properties within the outer disk of T=3000K and N$_H$$>10^{10}$ cm$^{-3}$. Such a cool, dense region, not associated with areas of H I and He I emission, provides the first observational confirmation of predictions made by accretion disk models.Comment: 10 pages, 3 figures. Accepted for publication in ApJ Letter

Influence of Multiple Traumatic Event Types on Mental Health Outcomes: Does Count Matter?

The experience of potentially traumatizing events (PTEs) may be associated with conflicting outcomes: individuals may experience greater psychological distress (dose-response theory), or individuals may become more resilient against repeated PTEs (stress-inoculation theory). With limited empirical data comparing these theories, we examined the relationships between the count of lifetime PTE types and psychological outcomes [posttraumatic stress disorder (PTSD), depression, impaired distress tolerance] using linear and quadratic regressions. A linear relationship would support the dose-response theory, and a quadratic relationship would support the stress-inoculation theory. We also explored whether there was a threshold number of PTE types fostering resiliency before an increase of distressing outcomes. The sample included 123 (68.30% female) treatment-seeking patients at a community mental health center participating in a larger study (Contractor et al. in Psychiatry Research, 252, 252215–252222, 2017). Linear regression results indicated number of PTE types significantly predicted increasing PTSD and depression severity and distress tolerance difficulties. Quadratic regression model results were not significant. ROC analyses indicated exposure to at least 3.5 PTE types predicted PTSD with moderate accuracy. In conclusion, the dose-response theory was supported, with results indicating there may be a threshold count of lifetime PTE types (\u3e 3) influencing traumatic stress outcomes

Anomalous cooling of the massive white dwarf in U Geminorum following a narrow dwarf nova outburst

We obtained Hubble GHRS medium resolution (G160M grating) phase-resolved spectroscopic observations of the prototype dwarf nova U Geminorum during dwarf nova quiescence, 13 days and 61 days following the end of a narrow outburst. The spectral wavelength ranges were centered upon three different line regions: N V (1238\AA, 1242\AA), Si III (1300\AA) and He II (1640\AA). All of the quiescent spectra at both epochs are dominated by absorption lines and show no emission features. The Si III and He II absorption line velocities versus orbital phase trace the orbital motion of the white dwarf but the N~V absorption velocities appear to deviate from the white dwarf motion. We confirm our previously reported low white dwarf rotational velocity, V sin i= 100 km/s. We obtain a white dwarf orbital velocity semi-amplitude K1=107 km/s. Using the gamma-velocity of Wade (1981) we obtain an Einstein redshift of 80.4 km/s and hence a carbon core white dwarf mass of ~1.1 Msun. We report the first subsolar chemical abundances of C and Si for U Gem with C down by 0.05 with respect to the Sun, almost certainly a result of C depletion due to thermonuclear processing. This C-depletion is discussed within the framework of a weak TNR, contamination of the secondary during the common envelope phase, and mixing of C-depleted white dwarf gas with C-depleted matter deposited during a dwarf nova event. Remarkably the Teff of the white dwarf 13 days after outburst is only 32,000K, anomalously cooler than previous early post-outburst measurements. Extensive cooling during an extraordinarily long (210 days) quiescence followed by accretion onto an out-of-equilibrium cooled degenerate could explain the lower Teff.Comment: 16 pages AAS-Latex, 4 Figures, accepted for publication in Ap

Test–retest reliability of multidimensional dyspnea profile recall ratings in the emergency department: a prospective, longitudinal study

BACKGROUND: Dyspnea is among the most common reasons for emergency department (ED) visits by patients with cardiopulmonary disease who are commonly asked to recall the symptoms that prompted them to come to the ED. The reliability of recalled dyspnea has not been systematically investigated in ED patients. METHODS: Patients with chronic or acute cardiopulmonary conditions who came to the ED with dyspnea (N = 154) completed the Multidimensional Dyspnea Profile (MDP) several times during the visit and in a follow-up visit 4 to 6 weeks later (n = 68). The MDP has 12 items with numerical ratings of intensity, unpleasantness, sensory qualities, and emotions associated with how breathing felt when participants decided to come to the ED (recall MDP) or at the time of administration (“now” MDP). The recall MDP was administered twice in the ED and once during the follow-up visit. Principal components analysis (PCA) with varimax rotation was used to assess domain structure of the recall MDP. Internal consistency reliability was assessed with Cronbach’s alpha. Test–retest reliability was assessed with intraclass correlation coefficients (ICCs) for absolute agreement for individual items and domains. RESULTS: PCA of the recall MDP was consistent with two domains (Immediate Perception, 7 items, Cronbach’s alpha = .89 to .94; Emotional Response, 5 items; Cronbach’s alpha = .81 to .85). Test–retest ICCs for the recall MDP during the ED visit ranged from .70 to .87 for individual items and were .93 and .94 for the Immediate Perception and Emotional Response domains. ICCs were much lower for the interval between the ED visit and follow-up, both for individual items (.28 to .66) and for the Immediate Perception and Emotional Response domains (.72 and .78, respectively). CONCLUSIONS: During an ED visit, recall MDP ratings of dyspnea at the time participants decided to seek care in the ED are reliable and sufficiently stable, both for individual items and the two domains, that a time lag between arrival and questionnaire administration does not critically affect recall of perceptual and emotional characteristics immediately prior to the visit. However, test–retest reliability of recall over a 4- to 6-week interval is poor for individual items and significantly attenuated for the two domains