While survival after acute myocardial infarction has improved substantially, older adults remain at heightened risk for hospital readmissions and death. Evidence for the role of cognitive impairment ...in older myocardial infarction survivors’ risk for these outcomes is limited.
3041 patients aged ≥75 years hospitalized with acute myocardial infarction (mean age 82 ± 5 years, 56% male) recruited from 94 US hospitals. Cognition was assessed using the Telephone Interview for Cognitive Status; scores of <27 and <22 indicated mild and moderate/severe impairment, respectively. Readmissions and death at 6 months post-discharge were ascertained via participant report and medical record review. Associations between cognition and outcomes were evaluated with multivariable-adjusted logistic regression.
Mild and moderate/severe cognitive impairment were present in 11% and 6% of the cohort, respectively. Readmission and death at 6 months occurred in 41% and 9% of participants, respectively. Mild and moderate/severe cognitive impairment were associated with increased risk of readmission (odds ratio OR 1.36; 95% confidence interval CI, 1.08-1.72 and OR 1.58; 95% CI, 1.18-2.12, respectively) and death (OR 2.19; 95% CI, 1.54-3.11 and OR 3.82; 95% CI, 2.63-5.56, respectively) in unadjusted analyses. Significant associations between moderate/severe cognitive impairment and death (OR 1.69; 95% CI, 1.10-2.59) persisted after adjustment for demographics, myocardial infarction characteristics, comorbidity burden, functional status, and depression, but not for readmissions.
Moderate-to-severe cognitive impairment is associated with heightened risk of death in older acute myocardial infarction patients in the months after hospitalization, but not with readmission. Routine cognitive screening may identify older myocardial infarction survivors at risk for poor outcomes who may benefit from closer oversight and support in the post-discharge period.
Context. Stellar mergers are expected to take place in numerous circumstences in the evolution of stellar systems. In particular, they are considered as a plausible origin of stellar eruptions of the ...V838 Mon type. V1309 Sco is the most recent eruption of this type in our Galaxy. The object was discovered in September 2008. Aims. Our aim is to investigate the nature of V1309 Sco. Methods. V1309 Sco has been photometrically observed in course of the OGLE project since August 2001. We analyse these observations in different ways. In particular, periodogram analyses were done to investigate the nature of the observed short-term variability of the progenitor. Results. We find that the progenitor of V1309 Sco was a contact binary with an orbital period of ~1.4 day. This period was decreasing with time. The light curve of the binary was also evolving, indicating that the system evolved towards its merger. The violent phase of the merger, marked by the systematic brightenning of the object, began in March 2008, i.e. half a year before the outburst discovery. We also investigate the observations of V1309 Sco during the outburst and the decline and show that they can be fully accounted for within the merger hypothesis. Conclusions. For the first time in the literature we show from direct observations that contact binaries indeed end up by merging into a single object, as was suggested in numerous theoretical studies of these systems. Our study also shows that stellar mergers indeed result in eruptions of the V838 Mon type.
Context
. Close binary central stars of planetary nebulae (PNe) must have formed through a common envelope evolution during the giant phase experienced by one of the stars. Transfer of the angular ...momentum from the binary system to the envelope leads to the shortening of the binary separations from the radius of red giant to the radius of the order of few tenths of AU. Thus, close binary central stars of planetary nebulae are laboratories to study the common envelope phase of evolution. The close binary fraction in the Galaxy has been measured in various sky surveys, but the close binary fraction is not yet well constrained for the Magellanic Clouds, and our results may help the study of common envelope evolution in low-metallicity environments.
Aims
. This paper presents a continuation of our study of variability in the Magellanic Cloud planetary nebulae on the basis of data from the OGLE survey. Previously, we had analysed the OGLE data in the Small Magellanic Cloud. Here, the study is extended to the Large Magellanic Cloud (LMC). In this paper we search for close binary central stars with the aim to constrain the binary fraction and period distribution in the LMC.
Methods
. We identified 290 counterparts of PNe in the LMC in the
I
-band images from the OGLE-III and OGLE-IV surveys. However, the light curves of ten objects were not accessible in the OGLE database, and thus we analysed the time series photometry of 280 PNe.
Results
. In total, 32 variables were found, but 5 of them turned out to be foreground objects. Another 18 objects show irregular or regular variability that is not attributable to the binarity of their central stars. Their status and the nature of their variability will be verified in the follow-up paper. Nine binary central stars of PNe with periods between 0.24 and 23.6 days were discovered. The obtained fraction for the LMC PNe is 3.3
-1.6
+2.6
% without correcting for incompleteness. This number is significantly lower than the 12–21% derived in the analogous search in the Galactic bulge. We discuss this difference, taking into account observational biases. The lower binary fraction suggests a lower efficiency of the common envelope phase in producing close binaries in the LMC compared to the Galaxy.
Aims. We study the star-formation history of the Galactic bulge, as derived from the age distribution of the central stars of planetary nebulae that belong to this stellar population. Methods. The ...high resolution imaging and spectroscopic observations of 31 compact planetary nebulae are used to derive their central star masses. We use the Blöcker post asymptotic giant branch (post-AGB) evolutionary models, which are accelerated by a factor of three in this case to better fit the white dwarf mass distribution and asteroseismological masses. Initial-final mass relations (IFMR) are derived using white dwarfs in clusters. These are applied to determine original stellar masses and ages. The age distribution is corrected for observational bias as a function of stellar mass. We predict that there are about 2000 planetary nebulae in the bulge. Results. The planetary nebula population points at a young bulge population with an extended star-formation history. The Blöcker tracks with the cluster IFMR result in ages, which are unexpectedly young. We find that the Blöcker post-AGB tracks need to be accelerated by a factor of three to fit the local white dwarf masses. This acceleration extends the age distribution. We adjust the IFMR as a free parameter to map the central star ages on the full age range of bulge stellar populations. This fit requires a steeper IFMR than the cluster relation. We find a star-formation rate in the Galactic bulge, which is approximately constant between 3 and 10 Gyr ago. The result indicates that planetary nebulae are mainly associated with the younger and more metal-rich bulge populations. Conclusions. The constant rate of star-formation between 3 and 10 Gyr agrees with suggestions that the metal-rich component of the bulge is formed during an extended process, such as a bar interaction.
The study aimed to estimate the prevalence of depression and anxiety among university students during the peak of COVID‑19 pandemic in the Slovak Republic in December 2020. The secondary goal was to ...compare results with a study from 2018 at the same university.
A web-based cross-sectional study was administered at the Comenius University in Bratislava. The final sample consisted of 1,786 participants (approx. 80 % females) with the mean age and standard deviation of M=21.15 and SD=3.53. An online battery of self-report measures of depression, anxiety, perceived stress, loneliness, and resilience was administered.
The prevalence rates of moderately severe to‑severe depression and anxiety were 34.3 % and 20.1 %, respectively. Depression and anxiety were associated with younger age, higher perception of stress, higher loneliness, and lower resilience. In comparison with 2018, we found a two-fold increase in depression and anxiety. The increase was present across most of the depression and anxiety symptoms.
The result of the study revealed elevated rates of depression and anxiety during the second wave of COVID-19 pandemic in Slovakia. Various demographic and psychological factors were associated with more severe depression and anxiety among university students. Some subgroups of students are at the higher risk of mental health problems (Tab. 4, Ref. 26).
We selected a sample of post-AGB candidates in the Magellanic Clouds on the basis of their near- and mid-infrared colour characteristics. Fifteen of the most optically bright post-AGB candidates were ...observed with the South African Large Telescope in order to determine their stellar parameters and thus to validate or discriminate their nature as post-AGB objects in the Magellanic Clouds. The spectral types of absorption-line objects were estimated according to the MK classification, and effective temperatures were obtained by means of stellar atmosphere modelling. Emission-line objects were classified on the basis of the fluxes of the emission lines and the presence of the continuum. Out of 15 observed objects, only 4 appear to be genuine post-AGB stars (27%). In the SMC, 1 out of 4 is post-AGB, and in the LMC, 3 out 11 are post-AGB objects. Thus, we can conclude that the selected region in the colour-colour diagram, while selecting the genuine post-AGB objects, overlaps severely with other types of objects, in particular young stellar objects and planetary nebulae. Additional classification criteria are required to distinguish between post-AGB stars and other types of objects. In particular, photometry at far-IR wavelengths would greatly assist in distinguishing young stellar objects from evolved ones. On the other hand, we showed that the low-resolution optical spectra appear to be sufficient to determine whether the candidates are post-AGB objects.
Aims. The evolution of central stars of planetary nebulae was so far documented in just a few cases. However, spectra collected a few decades ago may provide a good reference for studying the ...evolution of central stars using the emission line fluxes of their nebulae. We investigated evolutionary changes of the O iii 5007 Å line flux in the spectra of planetary nebulae. Methods. We compared nebular fluxes collected during a decade or longer. We used literature data and newly obtained spectra. A grid of cloudy models was computed using existing evolutionary models, and the models were compared with the observations. Results. An increase of the O iii 5007 Å line flux is frequently observed in young planetary nebulae hosting H-rich central stars. The increasing nebular excitation is the response to the increasing temperature and hardening radiation of the central stars. We did not observe any changes in the nebular fluxes in the planetary nebulae hosting late-type Wolf-Rayet (WR) central stars. This may indicate a slower temperature evolution (which may stem from a different evolutionary status) of late-WR stars. Conclusions. In young planetary nebulae with H-rich central stars, the evolution can be followed using optical spectra collected during a decade or longer. The observed evolution of H-rich central stars is consistent with the predictions of the evolutionary models provided in the literature. Late-WR stars possibly follow a different evolutionary path.
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