Background
Most treatments for cancer cause a decline in patients' health‐related quality of life (HRQoL). Limiting this decline is a universal goal for healthcare providers. Using minimally invasive ...instead of open surgical techniques might be one way to achieve this. The aim of this study was to compare postoperative HRQoL after open and laparoscopic liver resection.
Methods
This was a predefined substudy of an RCT comparing open with laparoscopic liver resection. Patients with colorectal liver metastases were assigned randomly to open or laparoscopic parenchyma‐sparing liver resection. HRQoL was assessed with the Short Form 36 questionnaire at baseline, and 1 and 4 months after surgery.
Results
A total of 280 patients were randomized, of whom 273 underwent surgery (129 laparoscopic, 144 open); 682 questionnaires (83.3 per cent) were available for analysis. One month after surgery, patients in the laparoscopic surgery group reported reduced scores in two HRQoL domains (physical functioning and role physical), whereas those in the open surgery group reported reduced scores in five domains (physical functioning, role physical, bodily pain, vitality and social functioning). Four months after surgery, HRQoL scores in the laparoscopic group had returned to preoperative levels, whereas patients in the open group reported reduced scores for two domains (role physical and general health). The between‐group difference was statistically significant in favour of laparoscopy for four domains after 1 month (role physical, bodily pain, vitality and social functioning) and for one domain after 4 months (role physical).
Conclusion
Patients assigned to laparoscopic liver surgery reported better postoperative HRQoL than those assigned to open liver surgery. For role limitations caused by physical health problems, patients in the laparoscopic group reported better scores up to 4 months after surgery. Registration number: NCT01516710 (
http://www.clinicaltrials.gov).
Antecedentes
La mayoría de los tratamientos para el cáncer causan una disminución de la calidad de vida relacionada con la salud (health‐related quality of life, HRQoL) de los pacientes. Limitar este declive es un objetivo universal para los proveedores de atención médica. El uso de técnicas quirúrgicas mínimamente invasivas en lugar de abiertas podría ser una forma de lograrlo. El objetivo de este estudio fue comparar la HRQoL postoperatoria después de la resección hepática abierta y laparoscópica.
Métodos
Se trata de un subestudio predefinido de un ensayo aleatorizado y controlado que comparó la resección hepática abierta con la laparoscópica. Los pacientes con metástasis hepáticas colorrectales se asignaron aleatoriamente al grupo de resección hepática con preservación de parénquima por vía abierta o por vía laparoscópica. La HRQoL se evaluó con el cuestionario abreviado SF‐36 en el momento basal y al cabo de 1 y 4 meses después de la cirugía.
Resultados
Un total de 280 pacientes fueron aleatorizados, de los cuales 273 se sometieron a cirugía (129 = laparoscópica, 144 = abierta) y hubo 682 cuestionarios (83%) disponibles para el análisis. Un mes después de la cirugía, los pacientes del grupo de cirugía laparoscópica presentaron puntuaciones reducidas en dos items de HRQoL (función física y rol físico), mientras que los pacientes del grupo de cirugía abierta presentaron puntuaciones reducidas en cinco items (función física, rol físico, dolor corporal, vitalidad y función social). Cuatro meses después de la cirugía, el grupo de cirugía laparoscópica había vuelto a los niveles preoperatorios de la HRQoL, mientras que los pacientes del grupo de cirugía abierta presentaron puntuaciones reducidas para dos items (función física y salud general). La diferencia entre los grupos fue estadísticamente significativa a favor de la laparoscopia para cuatro items después de un mes de la cirugía (rol físico, dolor corporal, vitalidad y función social) y para un ítem (rol físico) después de cuatro meses.
Conclusión
Los pacientes asignados a cirugía hepática laparoscópica presentaron mejor HRQoL postoperatoria que los pacientes asignados a cirugía hepática abierta. Para las limitaciones de roles causadas por problemas físicos de salud, los pacientes de cirugía laparoscópica presentaron mejores puntuaciones a los cuatro meses tras la intervención quirúrgica.
In this substudy of an RCT, patients assigned to laparoscopic liver surgery reported better postoperative health‐related quality of life than patients assigned to open liver surgery.
Laparoscopic approach improves quality of life
We are entering an era of unprecedented quantities of data from current and planned survey telescopes. To maximize the potential of such surveys, automated data analysis techniques are required. Here ...we implement a new methodology for variable star classification, through the combination of Kohonen Self-Organizing Maps (SOMs, an unsupervised machine learning algorithm) and the more common Random Forest (RF) supervised machine learning technique. We apply this method to data from the K2 mission fields 0–4, finding 154 ab-type RR Lyraes (10 newly discovered), 377 δ Scuti pulsators, 133 γ Doradus pulsators, 183 detached eclipsing binaries, 290 semidetached or contact eclipsing binaries and 9399 other periodic (mostly spot-modulated) sources, once class significance cuts are taken into account. We present light-curve features for all K2 stellar targets, including their three strongest detected frequencies, which can be used to study stellar rotation periods where the observed variability arises from spot modulation. The resulting catalogue of variable stars, classes, and associated data features are made available online. We publish our SOM code in python as part of the open source pymvpa package, which in combination with already available RF modules can be easily used to recreate the method.
Using Campaign 15 data from theK2mission, we have discovered a triply eclipsing triple star system: EPIC 249432662. The inner eclipsing binary system has a period of 8.23 d, withshallow∼3 per cent ...eclipses. During the entire 80-d campaign, there is also a single eclipse event of a third body in the system that reaches a depth of nearly 50 per cent and has a total duration of 1.7 d, longer than for any previously known third-body eclipse involving unevolved stars. The binary eclipses exhibit clear eclipse timing variations. A combination of photodynamical modeling of the light curve, as well as seven follow-up radial velocity measurements, has led to a prediction of the subsequent eclipses of the third star with a period of 188 d. A campaign of follow-up ground-based photometry was able to capture the subsequent pair of third-body events as well as two further 8-d eclipses. A combined photo-spectro-dynamical analysis then leads to the determination of many of the system parameters. The 8-d binary consists of a pair of M stars, while most of the system light is from a K star around which the pair of M stars orbits.
ABSTRACT
BG Ind is a well-studied, bright, nearby binary consisting of a pair of F stars in a 1.46-d orbit. We have discovered in the TESS light curve for TIC 229804573 (aka BG Ind), a second ...eclipsing binary in the system with a 0.53-d period. Our subsequent analyses of the recent TESS and archival ground-based photometric and radial velocity (RV) data reveal that the two binaries are gravitationally bound in a 721-d period, moderately eccentric orbit. We present the results of a joint spectro-photodynamical analysis of the eclipse timing variation curves of both binaries based on TESS and ground-based archival data, the TESS light curve, archival RV data, and the spectral energy distribution, coupled with the use of PARSEC stellar isochrones. We confirm prior studies of BG Ind that found that the brighter binary A consists of slightly evolved F-type stars with refined masses of 1.32 and 1.43 M⊙, and radii of 1.59 and 2.34R⊙. The previously unknown binary B has two less massive stars of 0.69 and 0.64 M⊙ and radii of 0.64 and 0.61R⊙. Based on a number of different arguments that we discuss, we conclude that the three orbital planes are likely aligned to within 17○.
ABSTRACT
In this work we report the discovery and analysis of three new triply eclipsing triple star systems found with the TESS mission during its observations of the northern skies: TICs 193993801, ...388459317, and 52041148. We utilized the TESS precision photometry of the binary eclipses and third-body eclipsing events, ground-based archival and follow-up photometric data, eclipse timing variations, archival spectral energy distributions, as well as theoretical evolution tracks in a joint photodynamical analysis to deduce the system masses and orbital parameters of both the inner and outer orbits. In one case (TIC 193993801) we also obtained radial velocity measurements of all three stars. This enabled us to ‘calibrate’ our analysis approach with and without ‘truth’ (i.e. RV) data. We find that the masses are good to 1–3 per cent accuracy with RV data and 3–10 per cent without the use of RV data. In all three systems we were able to find the outer orbital period before doing any detailed analysis by searching for a longer-term periodicity in the ASAS-SN archival photometry data – just a few thousand ASAS-SN points enabled us to find the outer periods of 49.28 d, 89.86 d, and 177.0 d, respectively. From our full photodynamical analysis we find that all three systems are coplanar to within 1°−3°. The outer eccentricities of the three systems are 0.003, 0.10, and 0.62, respectively (i.e. spanning a factor of 200). The masses of the three stars {Aa, Ab, and B} in the three systems are: {1.31, 1.19, 1.34}, {1.82, 1.73, 2.19}, and {1.62, 1.48, 2.74} M⊙, respectively.
ABSTRACT
In this work, we report the discovery and analysis of six new compact triply eclipsing triple star systems found with the TESS mission: TICs 37743815, 42565581, 54060695, 178010808, ...242132789, and 456194776. All of these exhibit distinct third-body eclipses where the inner eclipsing binary (EB) occults the third (‘tertiary’) star, or vice versa. We utilized the TESS photometry, archival photometric data, and available archival spectral energy distribution curves (SED) to solve for the properties of all three stars, as well as many of the orbital elements. We describe in detail our SED fits, search of the archival data for the outer orbital period, and the final global photodynamical analyses. From these analyses, we find that all six systems are coplanar to within 0°−5°, and are viewed nearly edge on (i.e. within a couple of degrees). The outer orbital periods and eccentricities of the six systems are {Pout (days), e}: {68.7, 0.36}, {123, 0.16}, {60.7, 0.01}, {69.0, 0.29}, {41.5, 0.01}, {93.9, 0.29}, respectively, in the order the sources are listed above. The masses of all 12 EB stars were in the range of 0.7–1.8 M⊙ and were situated near the main sequence. By contrast, the masses and radii of the tertiary stars ranged from 1.5 to 2.3 M⊙ and 2.9 to 12 R⊙, respectively. We use this information to estimate the occurrence rate of compact flat triple systems..
The Random Transiter – EPIC 249706694/HD 139139 Rappaport, S.; Vanderburg, A.; Omohundro, M.R. ...
Monthly notices of the Royal Astronomical Society,
09/2019, Letnik:
488, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We have identified a star, EPIC 249706694 (HD 139139), that was observed during K2 Campaign 15 with the Kepler extended mission that appears to exhibit 28 transit-like events over the course of the ...87-day observation. The unusual aspect of these dips, all but two of which have depths of 200 ± 80 ppm, is that they exhibit no periodicity, and their arrival times could just as well have been produced by a random number generator. We show that no more than four of the events can be part of a periodic sequence. We have done a number of data quality tests to ascertain that these dips are of astrophysical origin, and while we cannot be absolutely certain that this is so, they have all the hallmarks of astrophysical variability on one of two possible host stars (a likely bound pair) in the photometric aperture. We explore a number of ideas for the origin of these dips, including actual planet transits due to multiple or dust emitting planets, anomalously large TTVs, S- and P-type transits in binary systems, a collection of dust-emitting asteroids, ‘dipper-star’ activity, and short-lived starspots. All transit scenarios that we have been able to conjure up appear to fail, while the intrinsic stellar variability hypothesis would be novel and untested.
Abstract
We present a strongly interacting quadruple system associated with the K2 target EPIC 220204960. The K2 target itself is a Kp = 12.7-mag star at Teff ≃ 6100 K, which we designate as ‘B-N’ ...(blue northerly image). The host of the quadruple system, however, is a Kp ≃ 17-mag star with a composite M-star spectrum, which we designate as ‘R-S’ (red southerly image). With a 3.2-arcsec separation and similar radial velocities and photometric distances, ‘B-N’ is likely physically associated with ‘R-S’, making this a quintuple system, but that is incidental to our main claim of a strongly interacting quadruple system in ‘R-S’. The two binaries in ‘R-S’ have orbital periods of 13.27 and 14.41 d, respectively, and each has an inclination angle of ≳89°. From our analysis of radial-velocity (RV) measurements, and of the photometric light curve, we conclude that all four stars are very similar with masses close to 0.4 M⊙. Both of the binaries exhibit significant eclipse-timing variations where those of the primary and secondary eclipses ‘diverge’ by 0.05 d over the course of the 80-d observations. Via a systematic set of numerical simulations of quadruple systems consisting of two interacting binaries, we conclude that the outer orbital period is very likely to be between 300 and 500 d. If sufficient time is devoted to RV studies of this faint target, the outer orbit should be measurable within a year.
ABSTRACT
We report the discovery with the Transiting Exoplanet Survey Satellite (TESS) of a third set of eclipses from V994 Herculis (V994 Her, TIC 424508303), previously only known as a doubly ...eclipsing system. The key implication of this discovery and our analyses is that V994 Her is the second fully characterized (2+2) + 2 sextuple system, in which all three binaries eclipse. In this work, we use a combination of ground-based observations and TESS data to analyse the eclipses of binaries A and B in order to update the parameters of the inner quadruple’s orbit (with a derived period of 1062 ± 2 d). The eclipses of binary C that were detected in the TESS data were also found in older ground-based observations, as well as in more recently obtained observations. The eclipse timing variations of all three pairs were studied in order to detect the mutual perturbations of their constituent stars, as well as those of the inner pairs in the (2 + 2) core. At the longest periods they arise from apsidal motion, which may help constraining parameters of the component stars’ internal structure. We also discuss the relative proximity of the periods of binaries A and B to a 3:2 mean motion resonance. This work represents a step forward in the development of techniques to better understand and characterize multiple star systems, especially those with multiple eclipsing components.
Abstract
We have discovered a young M star of mass 0.16 M⊙ and radius 0.63 R⊙, likely in the Upper Sco Association, that exhibits only a single 80 per cent deep occultation of 1-d duration. The star ...has frequent flares and a low-amplitude rotational modulation, but is otherwise quiet over 160 d of cumulative observation during K2 campaigns C2 and C15. We discuss how such a deep eclipse is not possible by one star crossing another in any binary or higher order stellar system in which no mass transfer has occurred. The two possible explanations we are left with are (1) orbiting dust or small particles (e.g. a disc bound to a smaller orbiting body, or unbound dust that emanates from such a body); or (2) a transient accretion event of dusty material near the corotation radius of the star. In either case, the time between such occultation events must be longer than ∼80 d. We model a possible orbiting occulter both as a uniform elliptically shaped surface (e.g. an inclined circular disc) and as a ‘dust sheet’ with a gradient of optical depth behind its leading edge. The required masses in such dust features are then ≳3 × 1019 g and ≳1019 g, for the two cases, respectively.
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