7 research outputs found
Period-luminosity relations of pulsating M giants in the solar neighbourhood and the Magellanic Clouds
We analyse the results of a 5.5-yr photometric campaign that monitored 247
southern, semi-regular variables with relatively precise Hipparcos parallaxes
to demonstrate an unambiguous detection of Red Giant Branch (RGB) pulsations in
the solar neighbourhood. We show that Sequence A' contains a mixture of AGB and
RGB stars, as indicated by a temperature related shift at the TRGB. Large
Magellanic Cloud (LMC) and Galactic sequences are compared in several ways to
show that the P-L sequence zero-points have a negligible metallicity
dependence. We describe a new method to determine absolute magnitudes from
pulsation periods and calibrate the LMC distance modulus using Hipparcos
parallaxes to find \mu (LMC) = 18.54 +- 0.03 mag. Several sources of systematic
error are discussed to explain discrepancies between the MACHO and OGLE
sequences in the LMC. We derive a relative distance modulus of the Small
Magellanic Cloud (SMC) relative to the LMC of \Delta \mu = 0.41 +- 0.02 mag. A
comparison of other pulsation properties, including period-amplitude and
luminosity-amplitude relations, confirms that RGB pulsation properties are
consistent and universal, indicating that the RGB sequences are suitable as
high-precision distance indicators. The M giants with the shortest periods
bridge the gap between G and K giant solar-like oscillations and M-giant
pulsation, revealing a smooth continuity as we ascend the giant branch.Comment: 12 pages, 17 figures, 1 table. Accepted for publication in MNRA
Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles - II. CO line survey of evolved stars: derivation of mass-loss rate formulae
We aim to (1) set up simple and general analytical expressions to estimate
mass-loss rates of evolved stars, and (2) from those calculate estimates for
the mass-loss rates of asymptotic giant branch (AGB), red supergiant (RSG), and
yellow hypergiant stars in our galactic sample. Rotationally excited lines of
CO are a very robust diagnostic in the study of circumstellar envelopes (CSEs).
When sampling different layers of the CSE, observations of these molecular
lines lead to detailed profiles of kinetic temperature, expansion velocity, and
density. A state-of-the-art, nonlocal thermal equilibrium, and co-moving frame
radiative transfer code that predicts CO line intensities in the CSEs of
late-type stars is used in deriving relations between stellar and
molecular-line parameters, on the one hand, and mass-loss rate, on the other.
We present analytical expressions for estimating the mass-loss rates of evolved
stellar objects for 8 rotational transitions of the CO molecule, apply them to
our extensive CO data set covering 47 stars, and compare our results to those
of previous studies. Our expressions account for line saturation and resolving
of the envelope, thereby allowing accurate determination of very high mass-loss
rates. We argue that, for estimates based on a single rotational line, the
CO(2-1) transition provides the most reliable mass-loss rate. The mass-loss
rates calculated for the AGB stars range from 4x10^-8 Msun/yr up to 8x10^-5
Msun/yr. For RSGs they reach values between 2x10^-7 Msun/yr and 3x10^-4
Msun/yr. The estimates for the set of CO transitions allow time variability to
be identified in the mass-loss rate. Possible mass-loss-rate variability is
traced for 7 of the sample stars. We find a clear relation between the
pulsation periods of the AGB stars and their derived mass-loss rates, with a
levelling off at approx. 3x10^-5 Msun/yr for periods exceeding 850 days.Comment: Accepted for publication by Astronomy and Astrophysics, 24 pages + 28
pages appendix, 20 figure
The relationship between surgical intensive care unit nurses' patient safety culture and adverse events
Background: Adverse events are often encountered in surgical intensive care units (ICUs), and most of them occur due to preventable errors. Establishment of a patient safety culture is recommended for preventing and reducing these errors. Aims: This study was performed to investigate the relationship between surgical ICU nurses' patient safety culture and adverse events. Design: This was a cross-sectional descriptive study. Methods: The study was performed in the surgical ICUs of four university hospitals in Izmir province, Turkey and was conducted in accordance with the Declaration of Helsinki and approved by an Ethics Committee. The sample comprised 113 nurses working in the surgical ICUs of the hospitals between November 2018 and February 2019. Data were collected using a questionnaire that comprised a demographic form, adverse events form, and patient safety culture hospital questionnaire. Student's t test, one-way analysis of variance, and logistic regression analyses were used to evaluate the data. P values .05 were considered significant. Results: At the end of the study, nurses' level of patient safety culture was found to be intermediate (65.5%), with the highest average positive response rate (PRR) obtained for teamwork within the units (65.5%) and the lowest average PRR obtained for the frequency of adverse event reporting (25.3%). There was a significant correlation between patient safety culture and adverse events (r = 0.027, P .05). Conclusions: Surgical ICUs nurses' level of patient safety culture was average, and there was a significant correlation between patient safety culture and adverse events. Relevance to clinical practice: Managers should establish a reliable system for reporting adverse events and encourage ICU nurses to report them. It is very important to adopt a non-punitive approach at instances when an adverse event is reported. © 2021 British Association of Critical Care Nurses.We would like to thank to all nurses for their replying our questionnaire
Relationship between self‐compassion and emotional intelligence in nursing students
Nursing focuses on meeting physical, social and emotional health-care needs of individuals, families and society. In health care, nurses directly communicate with patients and try to empathize with them. Nurses give care under emotionally intense conditions where the individual undergoes pain and distress. Research is aimed at analysing the correlation of self-compassion and emotional intelligence of nursing students. The population of the research consisted of all the undergraduate students (571 students) of the 2010-2011 fall semester of the department of nursing. An information form, Self-compassion Scale and Emotional Intelligence Assessment Scale were utilized to obtain data for the research. For the assessment of the findings of research, Statistical Package for Social Sciences 16.0 for Windows was utilized for statistical analysis. Results indicated that there is a correlation between self-compassion and emotional intelligence and that emotional intelligence, which includes the individual perceiving one's emotions and using the knowledge one gained from them to function while directing thoughts, actions and professional applications, has positive contributions to the features of nurses with developed self-compassion
Roles of Perceived Control and Coping Strategies on Depressive and Anxiety Symptoms of Turkish Adolescents
Looking for timing variations in the transits of 16 exoplanets
We update the ephemerides of 16 transiting exoplanets using our ground-based observations, new TESS data, and previously published observations including those of amateur astronomers. All these light curves were modeled by making use of a set of quantitative criteria with the exofast code to obtain mid-transit times. We searched for statistically significant secular and/or periodic trends in the mid-transit times. We found that the timing data are well modeled by a linear ephemeris for all systems except for XO-2 b, for which we detect an orbital decay with the rate of -12.95 ± 1.85 ms/yr that can be confirmed with future observations. We also detect a hint of potential periodic variations in the TTV data of HAT-P-13 b which also requires confirmation with further precise observations