75 research outputs found
Factors for Acute Kidney Injury Following Total Arch Replacement and Association with Temperature Management During Cardiopulmonary Bypass: A Single-center Retrospective Observational Study
Many patients develop acute kidney injury (AKI) after vascular surgery. In this retrospective observational study, we investigated the risk factors for AKI defined using the Kidney Disease Improving Global Outcomes criteria after total arch replacement (TAR). Additionally, we investigated the influence of temperature manage-ment during cardiopulmonary bypass (CPB) on postoperative renal function by propensity score-matched anal-ysis. We retrospectively analyzed 161 consecutive patients who underwent TAR between 2016 and 2019. Postoperative AKI occurred in 48.7% of the patients. In the multivariate analysis, male sex (odds ratio [OR] 3.95, 95% confidence interval [95%CI] 1.56-8.27, p = 0.002), ACE inhibitors/ARB medication (OR 3.19, 95%CI 1.49-6.82, p = 0.003), preoperative chronic kidney disease (OR 2.47, 95%CI 1.17-5.23, p = 0.02), pro-longed CPB time (OR 2.36, 95%CI 1.05-5.34, p = 0.04), and lower body ischemic time during CPB (OR 2.20, 95%CI 1.05-4.46, p = 0.04) were identified as independent risk factors for AKI. Propensity score-matched anal-ysis showed no significant difference in the risk of AKI following TAR between mild hypothermia or normo-thermia and moderate hypothermia (37.2% vs. 41.9%, p = 0.83). In conclusion, modifiable risk factors for AKI included prolonged CPB time and lower body ischemic time. Temperature management during CPB had no clear effect on outcomes
Scalar polarization window in gravitational-wave signals
Scalar polarization modes of gravitational waves, which are often introduced
in the context of the viable extension of gravity, have been actively searched.
However, couplings of the scalar modes to the matter are strongly constrained
by the fifth-force experiments. Thus, the amplitude of scalar polarization in
the observed gravitational-wave signal must be significantly suppressed
compared to that of the tensor modes. Here, we discuss the implications of the
experiments in the solar system on the detectability of scalar modes in
gravitational waves from compact binary coalescences, taking into account the
whole processes from the generation to the observation of gravitational waves.
We first claim that the energy carried by the scalar modes at the generation
is, at most, that of the tensor modes from the observed phase evolution of the
inspiral gravitational waves. Next, we formulate general gravitational-wave
propagation and point out that the energy flux hardly changes through
propagation as long as the background changes slowly compared to the wavelength
of the propagating waves. Finally, we show that the possible magnitude of
scalar polarization modes detected by the ground-based gravitational-wave
telescopes is already severely constrained by the existing gravity tests in the
solar system.Comment: 18 page
Detection of planet candidates around K giants, HD 40956, HD 111591, and HD 113996
Aims. The purpose of this paper is to detect and investigate the nature of
long-term radial velocity (RV) variations of K-type giants and to confirm
planetary companions around the stars.
Methods. We have conducted two planet search programs by precise RV
measurement using the 1.8 m telescope at Bohyunsan Optical Astronomy
Observatory (BOAO) and the 1.88 m telescope at Okayama Astrophysical
Observatory (OAO). The BOAO program searches for planets around 55 early K
giants. The OAO program is looking for 190 G-K type giants.
Results. In this paper, we report the detection of long-period RV variations
of three K giant stars, HD 40956, HD 111591, and HD 113996. We investigated the
cause of the observed RV variations and conclude the substellar companions are
most likely the cause of the RV variations. The orbital analyses yield P =
578.6 3.3 d, sin = 2.7 0.6 , = 1.4
0.1 AU for HD 40956; P = 1056.4 14.3 d, sin = 4.4 0.4
, = 2.5 0.1 AU for HD 111591; P = 610.2 3.8 d,
sin = 6.3 1.0 , = 1.6 0.1 AU for HD 113996.Comment: 10 pages, 12 figures. Accepted for publication in Astronomy &
Astrophysic
Substellar Companions to Seven Evolved Intermediate-Mass Stars
We report the detections of substellar companions orbiting around seven
evolved intermediate-mass stars from precise Doppler measurements at Okayama
Astrophysical Observatory. o UMa (G4 II-III) is a giant with a mass of 3.1
M_sun and hosts a planet with minimum mass of m_2sini=4.1 M_J in an orbit with
a period P=1630 d and an eccentricity e=0.13. This is the first planet
candidate (< 13 M_J) ever discovered around stars more massive than 3 M_sun. o
CrB (K0 III) is a 2.1 M_sun giant and has a planet of m_2sini=1.5 M_J in a
187.8 d orbit with e=0.19. This is one of the least massive planets ever
discovered around ~2 M_sun stars. HD 5608 (K0 IV) is an 1.6 M_sun subgiant
hosting a planet of m_2sini=1.4 M_J in a 793 d orbit with e=0.19. The star also
exhibits a linear velocity trend suggesting the existence of an outer, more
massive companion. 75 Cet (G3 III:) is a 2.5 M_sun giant hosting a planet of
m_2sini=3.0 M_J in a 692 d orbit with e=0.12. The star also shows possible
additional periodicity of about 200 d and 1880 d with velocity amplitude of
~7--10 m/s, although these are not significant at this stage. nu Oph (K0 III)
is a 3.0 M_sun giant and has two brown-dwarf companions of m_2sini= 24 M_J and
27 M_J, in orbits with P=530.3 d and 3190 d, and e=0.126 and 0.17,
respectively, which were independently announced by Quirrenbach et al. (2011).
The ratio of the periods is close to 1:6, suggesting that the companions are in
mean motion resonance. We also independently confirmed planets around k CrB (K0
III-IV) and HD 210702 (K1 IV), which had been announced by Johnson et al.
(2008) and Johnson et al. (2007a), respectively. All of the orbital parameters
we obtained are consistent with the previous results.Comment: 21 pages, 14 figures, accepted for publication in PAS
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