Prehospital delay after stroke symptom onset is a primary barrier to eligibility for reperfusion therapies. Decision delay is an understudied contributor to prehospital delay. We aimed to explore ...decision delay as a component of prehospital delay. For this correlational study, 170 Thai acute stroke patients were interviewed to explore their treatment-seeking decision factors: prior stroke knowledge, onset context, and cognitive, emotional, and behavioral factors. Participants’ mean age was 61.2 years, and 46% were women. Median decision delay and prehospital delay times were 120 and 372 minutes. Decision delay represented 49% of prehospital delays. Factors shortening decision delay were atrial fibrillation, prior stroke knowledge, perceived cause of symptoms as stroke, perceived severity of symptoms, and advice from bystanders to seek treatment. In contrast, seeking support from others and self-treatment affected prolonged decision delay. Shortening decision delay, often under the patient or bystander control, can reduce overall prehospital delay.
The clinical work of nurses across the United States was profoundly impacted by the Coronavirus (COVID-19) pandemic. Nurses in both hospital and outpatient settings had to adapt quickly to the ...continuously changing healthcare environment.
To describe nurses’ responses to open-ended questions of their clinical work adaption during the COVID-19 pandemic.
A descriptive, cross-sectional survey with four open-ended questions was completed by practicing HF nurses. Content analysis was used to analyze the written data.
The 127 nurses who provided one to four narrative responses, 55.1% were clinical registered nurses and 44.9% were advance practice nurses. Four categories emerged: changing paths exemplifies work challenges, developing technical skills and resources, asking better questions while listening, and showing resilience through new paths to optimize work.
Understanding perceptions of nurses’ adaptions to clinical work made during the pandemic provides insight into the challenges and opportunities for development in the future.
Context.
The Transiting Exoplanet Survey Satellite (TESS) mission is revolutionizing the blossoming area of asteroseismology, particularly of pulsating white dwarfs and pre-white dwarfs, thus ...continuing the impulse of its predecessor, the
Kepler
mission.
Aims.
In this paper, we present the observations from the extended TESS mission in both 120 s short-cadence and 20 s ultra-short-cadence mode of two pre-white dwarf stars showing hydrogen deficiency. We identify them as two new GW Vir stars, TIC 333432673 and TIC 095332541. We apply the tools of asteroseismology with the aim of deriving their structural parameters and seismological distances.
Methods.
We carried out a spectroscopic analysis and a spectral fitting of TIC 333432673 and TIC 095332541. We also processed and analyzed the high-precision TESS photometric light curves of the two target stars, and derived their oscillation frequencies. We performed an asteroseismological analysis of these stars on the basis of PG 1159 evolutionary models that take into account the complete evolution of the progenitor stars. We searched for patterns of uniform period spacings in order to constrain the stellar mass of the stars. We employed the individual observed periods to search for a representative seismological model.
Results.
The analysis of the TESS light curves of TIC 333432673 and TIC 095332541 reveals the presence of several oscillations with periods ranging from 350 to 500 s associated to typical gravity (
g
)-modes. From follow-up ground-based spectroscopy, we find that both stars have a similar effective temperature (
T
eff
= 120 000 ± 10 000 K) and surface gravity (log
g
= 7.5 ± 0.5), but a different He/C composition of their atmosphere. On the basis of PG 1159 evolutionary tracks, we derived a spectroscopic mass of
M
⋆
= 0.58
−0.08
+0.16
M
⊙
for both stars. Our asteroseismological analysis of TIC 333432673 allowed us to find a constant period spacing compatible with a stellar mass
M
⋆
∼ 0.60 − 0.61
M
⊙
, and an asteroseismological model for this star with a stellar mass
M
⋆
= 0.589 ± 0.020
M
⊙
, as well as a seismological distance of
d
= 459
−156
+188
pc. For this star, we find an excellent agreement between the different methods to infer the stellar mass, and also between the seismological distance and that measured with
Gaia
(
d
Gaia
= 389
−5.2
+5.6
pc). For TIC 095332541, we have found a possible period spacing that suggests a stellar mass of
M
⋆
∼ 0.55 − 0.57
M
⊙
. Unfortunately, we have not been able to find an asteroseismological model for this star.
Conclusions.
Using the high-quality data collected by the TESS space mission and follow-up spectroscopy, we have been able to discover and characterize two new GW Vir stars. The TESS mission is having, and will continue to have, an unprecedented impact on the area of white-dwarf asteroseismology.
ABSTRACT
The Kepler spacecraft observed the hot subdwarf star PHL 417 during its extended K2 mission, and the high-precision photometric light curve reveals the presence of 17 pulsation modes with ...periods between 38 and 105 min. From follow-up ground-based spectroscopy, we find that the object has a relatively high temperature of 35 600 K, a surface gravity of $\log g / {\rm cm\, s^{-2}}\, =\, 5.75$ and a supersolar helium abundance. Remarkably, it also shows strong zirconium lines corresponding to an apparent +3.9 dex overabundance compared with the Sun. These properties clearly identify this object as the third member of the rare group of pulsating heavy-metal stars, the V366-Aquarii pulsators. These stars are intriguing in that the pulsations are inconsistent with the standard models for pulsations in hot subdwarfs, which predicts that they should display short-period pulsations rather than the observed longer periods. We perform a stability analysis of the pulsation modes based on data from two campaigns with K2. The highest amplitude mode is found to be stable with a period drift, $\dot{P}$, of less than 1.1 × 10−9 s s−1. This result rules out pulsations driven during the rapid stages of helium flash ignition.
The impact of space weather events on satellite-based technologies (e.g. satellite navigation and precise positioning) is typically quantified on the basis of the total electron content (TEC) and ...temporal fluctuations associated with it. GNSS (global navigation satellite systems) TEC measurements are integrated over a long distance and thus may include contributions from different regions of the ionised atmosphere which may prevent the resolution of the mechanisms ultimately responsible for given observations. The purpose of the experiment presented here was to compare TEC estimates from EISCAT and GPS measurements. The EISCAT measurements were obtained along the same line of sight of a given GPS satellite observed from Tromsø. The present analyses focussed on the comparison of temporal fluctuations in the TEC between aligned GPS and EISCAT measurements. A reasonably good agreement was found between temporal fluctuations in TEC observed by EISCAT and those observed by a co-located GPS ionospheric monitor along the same line of sight, indicating a contribution from structures at E and F altitudes mainly to the total TEC in the presence of ionisation enhancements possibly caused by particle precipitation in the nighttime sector. The experiment suggests the great potential in the measurements to be performed by the future EISCAT_3D system, limited only in the localised geographic region to be covered.
ABSTRACT
HD 4539 (alias PG 0044 + 097 or EPIC 220641886) is a bright (V = 10.2) long-period V1093 Her-type subdwarf B (sdB) pulsating star that was observed by the Kepler spacecraft in its secondary ...(K2) mission. We use the K2 light curve (78.7 d) to extract 169 pulsation frequencies, 124 with a robust detection. Most of these frequencies are found in the low-frequency region typical of gravity (g-)modes, but some higher frequencies corresponding to pressure (p-)modes are also detected. Therefore HD 4539 is a hybrid pulsator and both the deep and surface layers of the star can potentially be probed through asteroseismology. The lack of any frequency splitting in its amplitude spectrum suggests that HD 4539 has a rotation period longer than the K2 run and/or that it is seen pole-on. From asymptotic period spacing we see many high-degree modes, up to l = 12, in the spectrum of HD 4539, with amplitudes as low as a few ppm. A large fraction of these modes can be identified and for ∼29 per cent of them we obtain a unique and robust identification corresponding to l ≤ 8. Our study includes also a new determination of the atmospheric parameters of the star. From low-resolution spectroscopy we obtain Teff = 22 800 ± 160 K, log g = 5.20 ± 0.02, and log(N(He)/N(H)) = −2.34 ± 0.05. By fitting the SED we obtain Teff = 23 470$^{+650}_{-210}$ K, R⋆ = 0.26 ± 0.01 R⊙, and M⋆ = 0.40 ± 0.08 M⊙. Moreover, from 11 high-resolution spectra we see the radial velocity variations caused by the stellar pulsations, with amplitudes of ≈150 m s−1 for the main modes, and we can exclude the presence of a companion with a minimum mass higher than a few Jupiter masses for orbital periods below ∼300 d.
We report the discovery of planetary companions orbiting four low-luminosity giant stars with
M
⋆
between 1.04 and 1.39
M
⊙
. All four host stars have been independently observed by the EXoPlanets ...aRound Evolved StarS (EXPRESS) program and the Pan-Pacific Planet Search (PPPS). The companion signals were revealed by multi-epoch precision radial velocities obtained in nearly a decade. The planetary companions exhibit orbital periods between ~1.2 and 7.1 yr, minimum masses of
m
p
sin
i
~ 1.8–3.7
M
J
, and eccentricities between 0.08 and 0.42. With these four new systems, we have detected planetary companions to 11 out of the 37 giant stars that are common targets in the EXPRESS and PPPS. After excluding four compact binaries from the common sample, we obtained a fraction of giant planets (
m
p
≳ 1– 2
M
J
) orbiting within 5 AU from their parent star of
f
= 33.3
−7.1
+9.0
%. This fraction is slightly higher than but consistent at the 1
σ
level with previous results obtained by different radial velocity surveys. Finally, this value is substantially higher than the fraction predicted by planet formation models of gas giants around stars more massive than the Sun.
Abstract
AQ Col (EC 05217-3914) is one of the first detected pulsating subdwarf B (sdB) stars and has been considered to be a single star. Photometric monitoring of AQ Col reveals a pulsation timing ...variation with a period of 486 days, interpreted as time delay due to reflex motion in a wide binary formed with an unseen companion with expected mass larger than 1.05
M
⊙
. The optical spectra and color–magnitude diagram of the system suggested that the companion is not a main-sequence star but a white dwarf or neutron star. The pulsation timing variation also shows that the system has an eccentricity of 0.424, which is much larger than any known sdB long period binary system. That might be due to the existence of another short period companion to the sdB star. Two optical spectra obtained on 1996 December 5 show a radial velocity change of 49.1 km s
−1
in 46.1 minutes, which suggests the hot subdwarf in the wide binary is itself a close binary formed with another unseen white dwarf or neutron star companion; if further observations show this interpretation to be correct, AQ Col is an interesting triple system worthy of further study.
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