Introduction. Median sternotomy represents a standard surgical access in cardiac surgery, despite the growing popularity of minimally invasive access. Posternotomy infections are a serious ...complication and are directly related to patients' survival in the short and long term. Despite prevention, their expression is still significant - from 0.5% to 6.8%, and associated hospital mortality rates range from 7% to 35%.
Aims. Analysis of frequency, risk factors, microbiological agents, prevention options and surgical techniques for deep wound infections after open heart surgery for a 17 - year period.
Materials and methods. For the period from October 2002 to June 2019, 146 (1.42% of 10,307 operated) patients were treated at the Cardiac Surgery Clinic at the University Hospital “St. Georgi "diagnosed with deep sternal infection. The study is a retrospective using data from medical records and hospital records. The Center of Disease Control (CDC) criteria were used to define deep sternal infections.
Results. The sex ratio is 2.04: 1 – men: women. The average age for both sexes is 65.4 years. The average stay of patients in the intensive care unit was 5 days (from 0 to 46 days), and the average total hospital stay was 15.6 days (from 5 to 55 days). Early postoperative mortality was 13,7%. The most common risk factors were diabetes mellitus, obesity and emergency surgery.
Conclusion. Cardiac surgery with total midline sternotomy is associated with a risk of developing mediastinitis. Despite the advances in cardiac surgery and the use of mini-invasive techniques, the rate of development of deep wound infections remains relatively high.
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We report the discovery of WTS-2 b, an unusually close-in 1.02-d hot Jupiter (M
P
= 1.12M
J, R
P
= 1.30R
J) orbiting a K2V star, which has a possible gravitationally bound M-dwarf companion at 0.6 ...arcsec separation contributing ∼20 per cent of the total flux in the observed J-band light curve. The planet is only 1.5 times the separation from its host star at which it would be destroyed by Roche lobe overflow, and has a predicted remaining lifetime of just ∼40 Myr, assuming a tidal dissipation quality factor of
.
is a key factor in determining how frictional processes within a host star affect the orbital evolution of its companion giant planets, but it is currently poorly constrained by observations. We calculate that the orbital decay of WTS-2 b would correspond to a shift in its transit arrival time of T
shift ∼ 17 s after 15 yr assuming
. A shift less than this would place a direct observational constraint on the lower limit of
in this system. We also report a correction to the previously published expected T
shift for WASP-18 b, finding that T
shift = 356 s after 10 yr for
, which is much larger than the estimated 28 s quoted in WASP-18 b discovery paper. We attempted to constrain
via a study of the entire population of known transiting hot Jupiters, but our results were inconclusive, requiring a more detailed treatment of transit survey sensitivities at long periods. We conclude that the most informative and straightforward constraints on
will be obtained by direct observational measurements of the shift in transit arrival times in individual hot Jupiter systems. We show that this is achievable across the mass spectrum of exoplanet host stars within a decade, and will directly probe the effects of stellar interior structure on tidal dissipation.
Chylothorax After Cardiac Surgery Vazhev, Z.; Dimitrov, K.; Stoev, H.
Acta medica Bulgarica,
07/2020, Volume:
47, Issue:
2
Journal Article
Peer reviewed
Open access
In the following article we present a case of postoperative chylothorax as rare and severe complication after cardiac surgery. We present a case of 56-year-old man after double-valve replacement ...procedure and aorto-coronary artery bypass grafting, including pedicled left internal mammary artery towards left anterior descending artery. By the tenth postoperative day the total amount of drained milky white fluid from the left pleural cavity reached the colossal volume of 13 040 ml, despite the conservative therapy with intravenous Sandostatin (Octreotide) and parenteral feeding with a solution rich in medium chain triglycerides and amino acids – OliClínomel. The results of the biochemical analysis confirmed the diagnosis chylothorax. On the tenth postoperative day, a revision of the left pleural cavity through left thoracotomy was performed and lesion of the thoracic duct was identified. The lesion was sutured and secured with fibrin tissue glue – Tissucol for definitive treatment of the lymphorrhagia. The combined therapeutic and surgical approach concerning this serious complication turned out to be effective, and the patient was discharged on the thirty-second postoperative day with significant clinical improvement without ultra-sound and x-ray data for left pleural effusion.
Abstract
We report on the discovery of four ultra-short-period (P ≤ 0.18 d) eclipsing M-dwarf binaries in the Wide-Field Camera (WFCAM) Transit Survey. Their orbital periods are significantly shorter ...than that of any other known main-sequence binary system, and are all significantly below the sharp period cut-off at P ∼ 0.22 d as seen in binaries of earlier-type stars. The shortest-period binary consists of two M4-type stars in a P = 0.112 d orbit. The binaries are discovered as part of an extensive search for short-period eclipsing systems in over 260 000 stellar light curves, including over 10 000 M-dwarfs down to J = 18 mag, yielding 25 binaries with P ≤ 0.23 d. In a popular paradigm, the evolution of short-period binaries of cool main-sequence stars is driven by the loss of angular momentum through magnetized winds. In this scheme, the observed P ∼ 0.22 d period cut-off is explained as being due to time-scales that are too long for lower-mass binaries to decay into tighter orbits. Our discovery of low-mass binaries with significantly shorter orbits implies that either these time-scales have been overestimated for M-dwarfs, e.g. due to a higher effective magnetic activity, or the mechanism for forming these tight M-dwarf binaries is different from that of earlier-type main-sequence stars.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope (UKIRT) in 2007 August. Light ...curves comprising almost 1200 epochs with a photometric precision of better than 1per cent to J 16 were constructed for 60000 stars and searched for periodic transit signals. For one of the most promising transiting candidates, high-resolution spectra taken at the Hobby-Eberly Telescope (HET) allowed us to estimate the spectroscopic parameters of the host star, a late-F main-sequence dwarf (V = 16.13) with possibly slightly subsolar metallicity, and to measure its radial velocity variations. The combined analysis of the light curves and spectroscopic data resulted in an orbital period of the substellar companion of 3.35d, a planetary mass of 4.01 ± 0.35MJ and a planetary radius of RJ. WTS-1b has one of the largest radius anomalies among the known hot Jupiters in the mass range 3-5MJ. The high irradiation from the host star ranks the planet in the pM class. PUBLICATION ABSTRACT
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Abstract
We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope (UKIRT) in 2007 ...August. Light curves comprising almost 1200 epochs with a photometric precision of better than 1 per cent to J ∼ 16 were constructed for ∼60 000 stars and searched for periodic transit signals. For one of the most promising transiting candidates, high-resolution spectra taken at the Hobby-Eberly Telescope (HET) allowed us to estimate the spectroscopic parameters of the host star, a late-F main-sequence dwarf (V = 16.13) with possibly slightly subsolar metallicity, and to measure its radial velocity variations. The combined analysis of the light curves and spectroscopic data resulted in an orbital period of the substellar companion of 3.35 d, a planetary mass of 4.01 ± 0.35 M
J and a planetary radius of
R
J. WTS-1b has one of the largest radius anomalies among the known hot Jupiters in the mass range 3-5 M
J. The high irradiation from the host star ranks the planet in the pM class.
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Context.
Stellar ages are key to improving our understanding of different astrophysical phenomena. However, many techniques to estimate stellar ages are highly model-dependent. The lithium depletion ...boundary (LDB), based on the presence or absence of lithium in low-mass stars, can be used to derive ages in stellar associations of between 20 and 500 Ma.
Aims.
The purpose of this work is to revise former LDB ages in stellar associations in a consistent way, taking advantage of the homogeneous
Gaia
parallaxes as well as bolometric luminosity estimations that do not rely on monochromatic bolometric corrections.
Methods.
We studied nine open clusters and three moving groups characterised by a previous determination of the LDB age. We gathered all the available information from our data and the literature: membership, distances, photometric data, reddening, metallicity, and surface gravity. We re-assigned membership and calculated bolometric luminosities and effective temperatures using distances derived from
Gaia
DR2 and multi-wavelength photometry for individual objects around the former LDB. We located the LDB using a homogeneous method for all the stellar associations. Finally, we estimated the age by comparing it with different evolutionary models.
Results.
We located the LDB for the twelve stellar associations and derived their ages using several theoretical evolutionary models. We compared the LDB ages among them, along with data obtained with other techniques, such as isochrone fitting, ultimately finding some discrepancies among the various approaches. Finally, we remark that the 32 Ori MG is likely to be composed of at least two populations of different ages.
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The GAPS Programme at TNG Fossati, L.; Guilluy, G.; Shaikhislamov, I. F. ...
Astronomy and astrophysics (Berlin),
2/2022, Volume:
658
Journal Article
Peer reviewed
Context.
Because of its proximity to an active K-type star, the hot Jupiter WASP-80b has been identified as a possible excellent target for detecting and measuring He
I
absorption in the upper ...atmosphere.
Aims.
Our aim was to look for, and eventually measure and model, metastable He
I
atmospheric absorption.
Methods.
We observed four primary transits of WASP-80b in the optical and near-infrared using the HARPS-N and GIANO-B high-resolution spectrographs attached to the Telescopio Nazionale
Galileo
telescope, focusing the analysis on the He
I
triplet. We further employed a three-dimensional hydrodynamic aeronomy model to understand the observational results.
Results.
We did not find any signature of planetary absorption at the position of the He
I
triplet with an upper limit of 0.7% (i.e. 1.11 planetary radii; 95% confidence level). We re-estimated the high-energy stellar emission, which we combined with a stellar photospheric model, to generate the input for the hydrodynamic modelling. We determined that, assuming a solar He to H abundance ratio, He
I
absorption should have been detected. Considering a stellar wind 25 times weaker than solar, we could reproduce the non-detection only by assuming a He to H abundance ratio about 16 times smaller than solar. Instead, considering a stellar wind ten times stronger than solar, we could reproduce the non-detection only with a He to H abundance ratio about ten times smaller than solar. We attempted to understand this result by collecting all past He
I
measurements and looking for correlations with high-energy stellar emission and planetary gravity, but without success.
Conclusions.
WASP-80b is not the only planet with an estimated sub-solar He to H abundance ratio, which suggests the presence of efficient physical mechanisms (e.g. phase separation, magnetic fields) capable of significantly modifying the He to H content in the upper atmosphere of hot Jupiters. The planetary macroscopic properties and the shape of the stellar spectral energy distribution are not sufficient for predicting the presence or absence of detectable metastable He in a planetary atmosphere, since the He abundance also appears to play a major role.
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